Agriculture importance Essay

Those of us who preach the gospel of agriculture with evangelical zeal find the text compelling and convincing. We are regularly possessed by the spirit only to look around and see out colleagues, in other sectors, in country management, or even our senior management doubting, yawning or subtly edging towards the door. We face the implicit query, â€Å"If agriculture can do such great things, why have they not yet happened? †1 The past decade has been one of agro-pessimism. The promises that agricultural development seem to hold did not materialise. This pessimism seemed to coincide with pessimism about Sub-Saharan Africa. Especially for Sub-Saharan Africa the hope was that economic development would be brought about by agricultural development. After the success of the green revolution in Asia, the hope was that a similar agricultural miracle would transform African economies. But this hope never materialised, agricultural productivity did not increase much in SSA (figure 1), and worse, the negative effects of the green revolution in Asia became more apparent, such as pesticide overuse and subsequent pollution. Also in Asia the yield increases tapered off. The sceptics put forward several arguments why agriculture is no longer an engine of growth2. For instance, the liberalisation of the 1990s and greater openness to trade has lead to a reduction in the economic potential of the rural sector: cheap imported Chinese plastic buckets out compete the locally produced pottery. On the other hand, it does mean cheaper (imported) supplies. With rapid global technical change and increasingly integrated markets, prices fall faster than yields rise. So, rural incomes fall despite increased productivity if they are net producers3. The integration of rural with urban areas means that healthy young people move out of agriculture, head to town, leaving behind the old, the sick and the dependent. It is often also the men who move to urban areas, leaving women in charge of the farm. This has resulted in the increased sophistication of agricultural markets (and value chains) which excludes traditional smallholders, who are poorly equipped to meet the demanding product specifications and timeliness of delivery required by expanding supermarkets. The natural resource base on which agriculture depends is poor and deteriorating. Productivity growth is therefore increasingly more difficult to achieve. Finally, multiplier effects occur when a change in spending causes a disproportionate change in aggregate demand. Thus an increase in spending produces an increase in national income and consumption greater than the initial amount spent. But as GDP rises and the share of agriculture typically decreases, the question is how important these multiplier effects are, especially when significant levels of poverty remain in rural areas, which is the case in middleincome countries4. The disappointment with agriculture led many donor organisations to turn away from agriculture, looking instead to areas that would increase the well-being of poor people, such as health and education. Those organisations that still focused on agriculture, such as the CGIAR, were put under pressure to focus more on reducing poverty, besides increasing agricultural productivity. However, since the beginning of the new century, there seems to be a renewed interest in agriculture. A review of major policy documents5, including the well-publicised Sachs report and the Kofi Annan report, show that agriculture is back on the agenda again. The most influential report, however, has been the World Development Report 2008 of the World Bank6. This report argues that growth in the agricultural sector 1 contributes proportionally more to poverty reduction than growth in any other economic sector and that therefore alone, the focus should be on the agricultural sector when achieving to reach MDG 1. A reassessment of the role of agriculture in development seems to be required. This policy paper addresses several timely though complex questions: †¢ First, how can or does agriculture contribute to economic development, and in particular how does it relate to poverty? †¢ Second, the agricultural sector has changed considerably in the past decades: what are the main drivers of this change? †¢ Third, what is the relationship between economic or agricultural growth and pro-poor development? †¢ Fourth, how does agriculture relate to other sectors in the economy? †¢ Fifth, who is included and who is excluded in agricultural development, specifically focusing on small farms? †¢ And finally, if agricultural development is indeed important to economic development, then why, despite all the efforts and investments, has this not led to more successes? 2. Agriculture and economic growth This section presents a number of factual observations describing how the agricultural sector changed in terms of productivity, contribution to economic growth, and indicating the relevance of the agricultural sector for poverty alleviation in different regions. Background: some facts In the discussion of the role of agriculture in economic development, a leading question is how agriculture contributes to economic growth, and especially to pro-poor growth. There seems to be a paradox in the role of agriculture in economic development. The share of agriculture contributing to GDP is declining over the years (see figure 1). At the same time, the productivity of for instance cereal yields has been increasing (see figure 2). It seems that as agriculture becomes more successful, its importance declines in the overall economy. Of course, other sectors in the economy can be even more successful, such as the Asian Tigers.

Swot for Marriott Copenhagen

Internal/ External: SWOT analysis Strength * Famous brand of Marriott hotel chain in 67 countries,focus on B2C and B2B market * Staff(130 full-time employees) and staffs turnover is only 5%- high retention level, but during summer time number of employees increases (full-time and part-time) * Advantage of location according to the centre of Copenhagen and water view * Discounts packages for customers (family discounts, free transportation before/ after cruise) and the points system * Company’s culture is orientated to the statement â€Å"How Marriott never forgets a guest. – high attention to the customer* Core product is experience for customers and also additional services * Green key hotel and Environmental Committee * A lot of rooms (383) and 11 conference rooms, which are big in European standards; * Mergers with Tivoli and transportation company Weaknesses * Customer satisfaction: 81. 2 % in 2009, 18. 8% of customers can influence negatively on reputation, becaus e of mouth-to-ear information distribution * High prices in 5* hotel (food and beverage, rooms), extra expenses (Wi-Fi); Opportunities To have more facilities: like swimming pool or water center, boat trips * Eco- food will support the idea of the â€Å"environmental fight† Threats * Monopolistic competition, 65 competitors: 3-5 star hotels in Copenhagen; * Financial situation: crisis, inflation influences on customer decisions[ 1 ]. http://marketingteacher. com/Lessons/lesson_swot. htm[ 2 ]. http://www. marriott. com/corporateinfo/glance. mi[ 3 ]. Asking receptionist[ 4 ]. http://www. marriott. com/hotels/hotel-deals/cphdk-copenhagen-marriott-hotel/? offerInfo=364544[ 5 ]. http://www. marriott. com/search/redeemRewardsPoints. mi[ 6 ]. http://www. dengroennenoegle. dk/English/Cases. aspx[ 7 ]. http://www. dengroennenoegle. dk/English/Cases. aspx[ 8 ]. http://www. marriott. com/hotels/hotel-rooms/cphdk-copenhagen-marriott-hotel/[ 9 ]. http://www. marriottdevelopment. com/index . html#brands/mhr/ performance

TSCA and REACH Essay Example | Topics and Well Written Essays - 250 words

TSCA and REACH - Essay Example However, the Congress has received two bills addressing TSCA reform and will deliberate on them soon. Here, TSCA is compared to chemical regulations in other nations, and arguments for and against its reform are presented. Chemical safety in the United States has garnered bipartisan support. Currently, there are two pieces of legislation introduced to Congress that address TSCA reform: the Alan Reinstein and Trevor Schaefer Toxic Chemical Protection Act, drafted by Senators Barbara Boxer and Edward Markey, and the Frank R Lautenberg Chemical Safety for the 21st Century Act, drafted by Senators David Udall and Tom Vitter. Each bill distributes the priorities of the EPA in different ways. The Boxer and Markey legislation prioritized public health, required the EPA to review chemicals more quickly, and ensured that the EPA’s chemical assessments were aligned with the recommendations of the National Academy of Sciences. Boxer and Markey’s bill would also preserve the states’ authority to restrict chemical use and enforce federal restrictions under state law. On the other hand, the language of the Vitter and Udall bill appears to favor industry, allowing the EPA up to seven years to re view each substance (Chemical Watch 2015). Although the future of chemical reform in the United States is uncertain, these two bills addressing the need for TSCA reform are certainly a step in the right direction. In the early 1970’s, there was increasing concern about industrial compounds and their potential adverse effects on the environment and human health. Research on industrial substances and potential harmful effects, such as fluorocarbons found in aerosols and their effects on the earth’s stratosphere were well underway (Markell 2010). Bischloromethylether (BCME), polybrominated biphenyls (PBBs), as well as polychlorinated biphenyls (PCBs) was ubiquitously

The high level of corruption in central and eastern Europe Essay

The high level of corruption in central and eastern Europe - Essay Example In relation, this essay will try to explain the high level of corruption in Central and Eastern Europe. The discussion will tackle the reasons of the social problem. It will also include the methods that to be adopted in dealing with corruption. Corruption is indeed a social and legal problem. It is a social problem since the society as a whole is the one primarily affected of its effects. In almost all sectors, traces of corruption are eminent. It is also a legal problem since it is punishable under the laws of the community. The nations of the world have created their own laws against corruption. Nevertheless, corruption is still a pressing problem. Only a few corrupt individuals are successfully convicted and punished. Thus, there is a need to devise strategies that would effectively curb the acts of the corruption especially in the developing world. In connection, the majority of the countries making up the Central and Eastern part of Europe are actually considered developing sta tes. Benjamin Olken describes corruption like a tax. It adds to the expenses of conducting businesses and providing public services. In countries where corruption is imminent, public services are often poor and inadequate. Corruption lessens the budget needed to effectively and efficiently serve the people in a community. On the side of the business sector, putting up and maintaining a business would be harder than ever due to corruption. As cited by Nathaniel Heller, corruption presents a great barrier to the development and progress of any nation.7 This statement is quite logical. Anyone can in fact understand the rationale behind such contention. In a country, if corruption is present, the budget for the delivery of basic services would be low, unproportioned, and insufficient. For instance, there would only be low budget for education and health. If this is the case, one could expect that teachers will have low salary and educational resources for students would be scarce. In another aspect, medical centers will not have enough supply of medicines and equipments to cure the minor diseases of the people. The ultimate problem about corruption is that it makes the rich people become richer while the poor becomes poorer. It is a fact that only rich persons can thrive in a system which is full of corruption. The poor citizens on the other hand bear the costs of corruption. There is a negative impact in this sense.8 Cor ruption per se destroys the very foundation of a society. It undermines the faith in government and unwinds a lot of links between citizens and governmental institutions.9 Stated otherwise, corruption is the reason why there are people who do not believe in the establishment of governments. They believe that a government does not bring them any good except poverty and injustices. This should not be the case. Corruption in CEE In Central and Eastern Europe, there have been numerous cases of official corruption ranging from top level positions to local levels and across governmental

Discussion on rolls of translators in localiczation and translation Term Paper

Discussion on rolls of translators in localiczation and translation memory environment - Term Paper Example Like the rest of the ‘knowledge sector,’ translators are obliged to work on computer screens and do their research using the web. Unlike their colleagues however, they have been propagating this new work environment and fomenting change precisely by their role in translating it. The most significant tool used until now by translators in the digital work environment is Translation Memory software, or TM. By putting the developments of the last 20 years in historical perspective and with particular attention to events over the last two, this article argues that TM is reaching its use-by date. It also examines the strong re-emergence of Machine Translation (MT) in response to TM's inability to cope with the increasing translating needs of today’s digital age. (p. ... For example physicians, public servants, theologians, writers and poets translated the work of their respective fields. (p. 200) The grooming of translation as a profession is based on a century’s time period but shaping translation into a new form of business is a story of recent times, as this paper looks at the work of some of the modern authors, Brian Mossop (2006) is no exception. According to him, â€Å"most changes over the past 20 years have been changes in translation as a business†. (p. 788) Further more, he has written that now days, there are now translations companies provide services internationally and deal with remotely located translators worldwide. He also gave his point of view on localization and wrote: Translation is starting to become a big business, increasingly integrating as suppliers the traditional cottage industry of freelances. The activity known as ‘localization’ has been added to existing translation business sectors, and it i s also one of several sectors where practitioners are in the process of acquiring distinct professional status (along with court and community interpreters). That said, it nay be noted in passing that ‘localization’ of Web page textual content is often just a new label for an old activity, namely free translation / adaptation. (p.788-789) According to Brian Mossop (2006), â€Å"some of the changes under way in the world of translation are not related to information technology at all†. He has used English translation as a global auxiliary language example. He also regarded this development as a new chapter in the history of lingua francas. (p. 788-792) As this paper looks into the work of modern writers and authors, one can not ignore Anthony Pym’s work on globalization and contribution to translation as

Family Folklore Tradition Essay Example | Topics and Well Written Essays - 1250 words

Family Folklore Tradition - Essay Example Instead, my father’s side of the family is expansive. He grew up with five brothers and two sisters, the collection of which is spread throughout the greater United States, in a variety of jobs and socioeconomic states. With some slight humor, our family reunions always occur at the home of my richest uncle – Pat. Our most recent family reunion occurred approximately two years ago. During this reunion all of my father’s sisters and brothers agreed to meet at my Uncle Pat’s home in Minnesota. Uncle Pat’s home is the obvious choice as it is an expansive estate on the water. During our first family reunion when I was a child I was struck by the size and amenities the estate contained, as I had never seen or experienced a home so large. My Uncle Pat was a highly successful stockbroker and his home reflects this affluence. In addition to living on the water, one of Pat’s neighbors is rumored to be the musician Prince – although we have neve r seen him. During the last family reunion the families arrived in Minnesota on the same day. Not unlike an episode from MTV’s Jersey Shore, or the Real World, the family that arrives first has the first choice of which room to take. As my Uncle’s home is fairly large, there are enough rooms for everyone to stay. Still, one of my uncles decided to stay at a hotel. Even as the families come together under the guise of friendship and shared background, there is always backstories and infighting that occurs among certain people. After the families have all arrived and settled into their rooms a wide variety of events take place. On the first full day of the reunion a large barbeque occurred in the backyard of the house. In addition to the families that arrived for the reunion, generally outside friends and neighbors are invited for the festivities. During the day things such as hot dogs and hamburgers are served and a variety of classic American amenities. While some peop le are eating others are engaging in discussions, or the children are playing video games or swimming in the pool. After everyone has eaten there is traditionally a large-scale volleyball game that occurs. This game is not very competitive, instead it functions to bring everyone together in a cooperative spirit, with children as young as five years old playing alongside forty year old men. The next day is generally reserved specifically for the family. While there is not a singular traditional event that occurs in this day, there are specific events that have been highly significant in my family tradition. For instance, during my last visit we visited the home that my father and his siblings grew up in. While I was initially resistant to the excursion, I soon came to greatly appreciate the experience. The home had long since been bought by another family, but they were selling it and agreed to let out family tour the home. While I envisioned the experience being boring, upon touring the home my father and his siblings began relaying stories that had occurred during their youth. For instance, my father talked about getting stuck in the laundry chute. My uncle showed us all how he would sneak in and out of the house without his parents finding out. While the experience was amusing, it also imbued me with great appreciation for the era and circumstances that my father and his family grew up in. This allowed me greater insight and perspective into his life. Towards the end of the week the family

Branding Research Proposal Example | Topics and Well Written Essays - 2000 words

Branding - Research Proposal Example With a clear level of branding architecture, an organization can decide on the level of branding that will receive the greatest support and emphasis. In addition, the organisation can also establish and define the relations between the various brands in the organisation. Branding has moved into the daily lives of individuals in the Western societies affecting more sectors than ever before as the competition for audiences among companies intensifies (Owen, 1993). Branding is no longer a concept limited to companies, as there has been a rise of the practice in universities and other institutions. However, as branding becomes a mainstream practice and concept, it risks being misinterpreted and misunderstood. This is because branding is not only creating a logo and graphics to represent a company, person, or country (Healey, 2008). Branding is encompassed by the perceptions of the reputation as well as the tangible look and feel of the company, service, product, individual, or country (H estad, 2013). It relates to the behaviour of the company as well as the customer experience. Therefore, the concept of branding, applies to aspects that are within and outside the organisation. Consumers usually generalize their attitudes and perceptions across services and products based on two key factors (Hansen & Christensen, 2004). These factors are the impression they form on product attributes and the credibility of the country of origin of a brand or product (Hansen & Christensen, 2004). The product attributes include value of money and product quality while the credibility of the country of origin of a product is based on the individual’s familiarity of the country of origin of the product. These two factors are responsible for the creation of a favourable perception in a consumer that influences them to purchase and use a particular product or brand. The challenge, however, is the formation of stereotypes that are responsible for influencing individuals’

Intrusion detection systems Essay Example | Topics and Well Written Essays - 2000 words

Intrusion detection systems - Essay Example IDS is the short form for the Intrusion Detection Systems. These systems basically find out the manner in which unwanted signals towards the systems are manipulated. In fact there are a host of different kinds that come under the IDS heading. Moreover, coming to the point of these manipulations which occur in the first place, we discern that these are the usual attacks that are carried out by the hackers who are skilled and quite adept at their work and even at times, script kiddies do play these tricks whereby they make use of the automated scripts to achieve their objectives. IDS thus looks at the malicious data traffic that is taking place in computer networks as well as tries its best at finding out the spots where the firewall would not play its active part and thus seize the chance of finding the loopholes that might exist within a computer and indeed the whole of the network under question. Thus what is left unattended and undiscovered by the computer firewall is usually caugh t by the IDS which makes its functions look all the more imperative in the related scheme of computer networking and security issues that arise every now and then.Thus vulnerable services are saved from the attacks and applications are saved as a result of the precaution which has been applied.The components which make up the IDS include the sensors, a console and a central engine. They are briefly highlighted here. Sensors play their active part in the generation of events related with security issues.

Presentation Assignment Example | Topics and Well Written Essays - 250 words - 1

Presentation - Assignment Example Our strategy is to become the clear market leader in internet sales. This strategy of choice will ensure that we give our customers the best services that is worth their money. This strategy also makes it easier for our company to focus on the intended objectives and ensure that our customers are left with the urge of getting even more. At Fingent, we are set to settle for nothing but the best in the market, seeing to it that we produce quality products and service delivery. In essence, we settle for nothing less than excellence. This will also set confidence in our company among our esteemed customers who will not think that we are just but making a buck whichever way we possibly can. To start with, our company has identified its target customers which is also the target market. Having this in place, we are going to be as unique as we possibly can to be able to outdo our competitors out there. We have also embarked on effective and efficient networking which will ensure that we widen our scope and network in the market. Hart, Ted, James M. Greenfield, and Michael W. Johnston.  Nonprofit Internet Strategies: Best Practices for Marketing, Communications, and Fundraising Success. Hoboken, N.J: Wiley, 2005. Internet

ALS (amyotrophic lateral sclerosis) Term Paper Example | Topics and Well Written Essays - 1500 words

ALS (amyotrophic lateral sclerosis) - Term Paper Example This may cause paralysis at the later stages of the disease. If a muscle is affected by death of its motor neurons, this means that it does not get nourishment. Therefore, the muscle wastes away (atrophy) leading to hardening of the muscle (sclerosis). The main characteristic of this disorder is the destruction and death of the motor neurons in the brain and spinal cord in which before their destruction they develop inclusions in their structures-the axon and cell bodies that are rich in protein. The proteins are believed to be as a result of a problem in the degeneration of protein and these inclusions have a substance called ubiquitin and this combines with one of the proteins associated with ALS for example TAR DNA binding protein. (Murray, 2006) As the motor neurons get destroyed in the lateral and anterior parts of the spinal cord, the neurons are replaced by astrocytes that cause sclerosis. The degeneration of the upper motor neurons that is located in the cortex of the brain results in paralysis, increased reflexes and stiffness of the affected muscles. The degeneration of the motor neurons that is located in the in stem and the horn-like part at the anterior of the spinal cord results in flaccid paralysis, weakness of muscles and atrophy of the muscles, decreased reflexes and decrease in the muscle tone. The initial symptoms of this disorder are generally, muscle weakness affecting mostly those of the arms and legs, cramping, difficulty in swallowing, problems in speech and breathing and stiffness of the muscle that has been affected. (Murray, 2006) When the clinical manifestation is first noticed in the arms and legs, it is referred to as limb-onset ALS whereas if the symptoms affect the speech first it is called bulbar-onset ALS. The bulbar symptoms include difficulty in speech, difficulty in swallowing, drooling, atrophy and fasciculation of the tongue. When the upper motor neurons are affected, the disorder is

Linguistic anthropology Essay Example for Free

Linguistic anthropology Essay Linguistic anthropology is defined as ‘an interdisciplinary field dedicated to the study of language as a cultural resource and speaking as a cultural practice’ (Duranti, 2001) or ‘investigate the relationship between communication and culture’ (Sociology and Anthropology Website, 2010). It is also ‘the study the role language plays in culturally patterned behavior’ (Stanton, 2000). This branch of anthropology utilizes ‘detailed documentation’ of people’s communicative interaction with each other in any social activity. It also focuses on subjective research through oral interviews, recorded transcription and active participation of the subjects. It has garnered interest from the academic field as more studies had been made with credible sources and maintaining the emphasis on systematic and empirical research. Language and culture are the key factors in the linguistic anthropology; it was often pointed out with linguists that children learn the language along with their society’s culture at the same time. Grammar, syntax, accent, dialects often arrived with surprising results. This branch of study often concludes the identity of the speakers; how they speak, why certain accents are received with prejudice or acceptance, etc. Having a linguist working with me, specializing in Political Science would be a very interesting and intellectual camaraderie. Culture is one of the significant factors in the Political Science field; its study is usually of game play of power and how to apply such influence on people. Linguistic anthropology’s methodology is also similar to that of Political Science. Interaction is necessary to achieve favor from the public masses whether for political campaigns or public relations within the government. Understanding different kinds of languages, even dialects, actually helped tremendously in comprehending the other parties’ identity in Society. Political Science is a study of power play and therefore must utilize soft power as much as possible to avoid damages in one’s society. Positive reinforcement to the different kinds of people, whether they are natives or foreigners, elite or poor, and men or women, would be impossible without understanding the language structure of the said subjects (Duranti, 2001). References: Duranti, A. (2001) Linguistic Anthropology. Retrieved on 5 May 2010 from, http://www. sscnet. ucla. edu/anthro/faculty/duranti/reprints/02ling_anth. pdf Stanton, W. (2000). Linguistic Anthropology of Education. Retrieved on 5 May 2010 from, http://www. gse. upenn. edu/~stantonw/pdf/lae. pdf Sociology and Anthropology Website. (2010). What is Linguistic Anthropology? Retrieved on 5 May 2010 from, http://www. mystfx. ca/academic/sociology/anthropology/LinguisticAnthropology. html

Economic Booms of China and India Essay Example for Free

Economic Booms of China and India Essay It has been well known that China and India are having an economic boom whilst the west is in a recession. The question is whether China and India are going to slip into a recession as their rate of growth is thought to be â€Å"unhealthy†, this would put the western countries back into recession which is a very worrying prospect for a slowly recovering western world. China’s GDP (growth domestic product) is now over $4,211 billion a growth from $53 billion in 1978. China is between a LEDC and a MEDC and is growing at a extremely fast rate which is thought to be â€Å"unhealthy†. China’s main port (which there are 200 of) are growing at a huge rate which cannot be sustainable the Port of Shenzhen is growing at over 25% annually to provide the world which China made products. The port is home to 39 shipping companies who have launched 131 international container routes. There are 560 ships on call at Shenzhen port on a monthly basis and also 21 feeder routes to other ports in the Pearl River Delta region. China just had a deceleration in growth which worried the whole world. The slowdown can be blamed on a variety of factors. Chinas government was aiming for a slight deceleration, as it tried to tame its real estate boom and rapid inflation. While the rate still is allot faster than the growth in the United Kingdom, it marks an uncomfortable soft patch for China. Over the last three decades, the country has barrelled ahead at an average of about 10% a year. This shows that the â€Å"unhealthy† growth of China of an average of 10% will eventually slow down and bring the whole world into a very bad recession. The economy of India is the eleventh largest in the world by nominal GDP and the third largest by purchasing power parity (PPP). The country is one of the G-20 major economies and a member of BRICS. On a per capita income basis, India ranked 140th by nominal GDP and 129th by GDP (PPP) in 2011, according to the IMF. However India’s economic growth is also much higher than it is in the western world but I believe their growth is much healthier than the growth in China. India’s industry only accounts for 28% of its GDP whereas in China that number is much higher. China and India share many similarities as they are both growing at a huge rate but China’s growth is mainly in industry which is much less sustainable. China is also relying on  the fact communism remains strong and doesn’t crash because if it does wages will rise and put western countries in recession. India designs much more unique high quality products which is much more sustainable than China’s large scale low quality batch production which is much less sustainable and that is the reason I believe that China is the biggest threat to the western world. I believe that China is the biggest threat to the western countries and would put the whole world into recession. Therefore I believe the countries should stop relying on China so heavily because China controls the whole world. If China did not believe in something a county did it could stop the exports to that country which would hugely affect that country. Therefore I believe that it is a threat to the west. I do not believe that India is YET such a threat as China but in less than 10 years I belive it may be just as much of a problem as china.

Development of CT Scans for Cancer Studies

Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute, Development of CT Scans for Cancer Studies Development of CT Scans for Cancer Studies According to the statistics presented by the World Health Organization (WHO), with around 7.4 million deaths (around 13% of the total death) in 2004, cancer is the leading cause of death throughout the world (WHO, 2009). These levels are expected to rise further in future, with an estimated 12 million death in 2030 (WHO, 2009). There are more than 100 different types of cancer (Crosta, n.d.), among them the Lung cancer, stomach cancer, colorectal cancer, liver cancer and the breast cancer are the most common types. Tobacco is the most important risk factor for cancer, with nearly 1.3 million deaths per year just due to lung cancer alone (WHO, 2009). Cancer At the primary level, human body consists of large number building blocks, called the cells. Under normal circumstances, new cells are formed by the body depending on the body requirement, in order to replace the dead cells. But sometimes, under abnormal conditions, there is an exponential (uncontrolled) increase in the formation and growth of new cells. The accumulation of these extra cells forms mass or lumps of tissues, called the tumor (National Cancer Institute, 2010). Most of the cancers, in general form tumors, but there are certain exceptions, like leukemia, that do not form tumors (in leukemia or blood cancer, the cancer cells hinder the normal blood functions due to abnormal cell disintegration in the blood stream (Crosta, n.d.)). The tumors can be of two types; benign tumor and malignant tumor. The benign tumors do not propagate to other sections of the body and have restrained growth (Crosta, n.d.), whereas the malignant tumor cells have the ability to invade into the sur rounding tissues. Also the malignant tumor cells can escape from their initial location and spread to other sections of the body through blood or lymph. Only the malignant tumors are cancerous in nature. Therefore, the cancer has three distinctive properties that distinguish malignant tumors from benign tumors: Uncontrolled growth Invasive nature Metastasis (ability to spread to other sections of the body) These disorders in cells are the result of the interaction between the genetic factors and external agents (which are called carcinogens) (WHO, 2009). The carcinogens can be categorized as (WHO, 2009): Biological carcinogens, like certain bacteria, viruses or parasites. Physical carcinogens, which includes the high energy radiations (ionizing radiations). Chemical carcinogens, these include substances like tobacco smoke, arsenic (water contaminant), aflatoxin (food contaminant), asbestos etc. Another factor essential in the development of cancer is the age. According to the studies conducted by the Cancer Research UK, the risk increase predominantly with increasing age, with nearly 74% of the cases of cancer diagnosed in people aged 60 and above (Cancer Research UK, 2009). Cancer Treatment Principle In case of normal cells there is specific pattern of growth, division and death (orderly destruction of cells is called apoptosis) (Crosta, n.d.). It is known that the cancer is the result of the uncontrolled growth of cells which do not die (Crosta, n.d.), that is, the apoptosis process fails in the cancer cells. The cancer cells thus do not die and rather continue to grow, resulting in the formation of tumors. As the problem in the cancer cells lies in the DNA, therefore a possible treatment of cancer is the destruction of the DNA in cancer cells, leading to a self initiated destruction of the cells. There are various methods used for the treatment of cancer depending upon the type of cancer. The most common types of treatment are (Fayed, 2009): Surgery Chemotherapy Radiation therapy or Radiotherapy Biologic or Targeted Therapy Radiotherapy Radiotherapy, also referred to as radiation therapy, is one of the most common types of treatments used for cancer. It is the utilization of higher energy radiations like x-rays, gamma rays in order to kill cancer cells, treatment of thyroid disorder and even some blood disorders, in a particular section (effected part) of the body (Nordqvist, 2009). The high energy ionizing radiations can be produced using a number of radioactive substrates like Cobalt (60Co), Radium (228Ra), Iodine (131I), Radon (221Rn), Cesium (137Cs), Phosphorus (32P), Gold (198Au), Iridium (192Ir), and Yttrium (90Y) (Howington, 2006). The cancer cells have the ability to multiply faster than other body cells. The high energy ionizing radiations are more destructive towards the faster growing cells, and thus they damage the cancer cell more than the other body cells (Mason, 2008). These high energy radiations like gamma rays and x-rays; especially damage the DNA inside these cancer cells (or tumor cells) thereby annihilating the ability of the cells to reproduce or grow. Apart from treatment of cancer, radiation therapy is also used to shrink a tumor before being surgically removed (Mason, 2008). Depending upon the method of irradiation, the process of radiation therapy is categorized into two forms (Mason, 2008): External Radiotherapy In this method (more common), the infected part of the body (tumor) is irradiated by high energy x-rays from outside the body. Internal Radiotherapy For this method, a radioactive substance are injected (or taken orally) into the body (close to the tumor) in the form of fluids. These substances, taken up by the cancer cells, radiate the tumor through internal beam radiation (or interstitial radiation) (Mason, 2008). Radiotherapy Planning A careful planning is essentially required for radiation therapy, as over exposure can be critically dangerous to healthy tissues in the body. The ionizing radiations have side effects, therefore once the full dose of radiations is decided; the patient is given these radiations in the form of small doses in a series of therapy sessions (Cancer Research UK, 2009). Each small dose of radiation is called a fraction. The gap between sessions provides the recovery time for the body, which may depend on the type of cancer and patients health condition. The area of the body that is radiated during the treatment is called the radiotherapy field and the section inside the body that experiences the maximum exposure dose is called the target volume (Cancer Research UK, 2009). The doctors decide the marginal area around the tumor that should be radiated to encapsulate any movement of the cancer cells. In order to accurately determine the position of tumor (or target volume), body scans are done. Computed Tomography (CT) scans are done as a planning procedure, this provides vital information regarding the location of the tumor as well as the kind of treatment required by the patient (Cancer Research UK, 2009). The radiotherapy treatment planning process can be divided into 6 major steps . Computer Tomography (CT) Scan The invention of Computer Tomography (CT) scanned is credited to Sir Godfrey Hounsfield in early 1970s, for which he along with Allen Cormack, was awarded the Nobel Prize in 1979 (Smith, n.d.). A CT scanner, also known as the Computed Axial Tomography (CAT) scanner uses X-rays to produce cross sectional images (or slices) of the body like a slice in a loaf of bread (FDA, 2010). The word tomography suggests the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram) (Nordqvist, 2009). These cross-sectional slides render an accurate picture of the size and location of the tumor along with the position of major organs in the body (Cancer Research UK, 2009). This would be essentially useful during the radiotherapy process, where these can be used to lower the dose of radiations on the organs. It is known that in case of radiation therapy treatment, the doses are given in fractions over a certain period of time (to prevent major side effects), which may vary from few weeks to months. Thus, before each fraction of radiation dose, computed tomography (CT) scan of the patients is done to determine the exact location of the tumor or cancer cells. So in case the full dose has been divided into 30 fractions, then the patient has to undergo 30 CT scans, each before a fractional therapy. The machine used for the radiation therapy planning is known as the simulator (Cancer Research UK, 2009). The simulator identifies the position of the tumor and marks the position of radiation on the body with the help of light rays. The radiographer uses ink markers on the body before the actual radiotherapy is begun. These linear ink marks are used by the radiographer for positioning the machine for radiotherapy (Cancer Research UK, 2009). Simulators take the pictures (CT scans) in the form of X-rays, which locates the accurate tumor position for the radiographer to carry out the treatment. During a CT scan, it is essential that the person remains completely still so that the measurements are accurate. In order to insure the correct position supports like neck rest, chest board or arm pole are used (Cancer Research UK, 2009). In case of children it is ensured by giving proper sedatives. Sometimes, under critical condition, extra measures are taken in order to prevent essential organs from being radiated during the therapy. These measures include injecting fluids or dyes which mark the position of vital human organs in the CT scan (Cancer Research UK, 2009). These markers may be given orally, through injections or rectally depending upon the requirement. Using this vital information from the CT scans, a treatment plan for radiation therapy is prepared. This plan indicates the position and direction of the radiations during the therapy, so as to minimize the exposure of healthy cells and organs. The scans generated by a CT scanner are in the form of 2 dimensional (2-D) slides, but by the used of digital geometry processing they can be used to generate a 3 dimensional (3-D) images of the body (Nordqvist, 2009). This can be achieved by integrating all the slides (along the same axis) together using a computer system. The CT scan can be understood as a technically advanced format of X-rays machines. The x-rays images are produced by the projection of a broad beam of x-rays on a film after passing through the body (Medindia, 2010). It provides a 2-dimentional projection of the body, where much of the information is lost. In case of CT scan, a thin beam of x-rays is absorbed by the detector after passing though the patients body (Medindia, 2010). Like the x-ray process, the CT scanning is a painless process for the patients but has been known to be accompanied with some side effects. These side effects may vary from the patient to patient depending upon the amount of radiation dose and health of the patient. The detailed discussion on the health effects of CT scanning has been discussed in the later sections of the project. Theory In order to understand the working of a computed tomography (CT) scanner it is essential to understand the properties of ionizing radiations (X-rays) used in the scanning process. The electromagnetic radiations are the arrangement of electric-field and magnetic-field vectors perpendicular to each other and also perpendicular to the propagation direction of the wave (Resnick et al., 2009). These Electromagnetic radiations have penetrating powers, which are directly dependent on the energy (or frequency) of these radiations. So that radiations with higher frequency have higher penetration powers. Therefore, on the basic the energy, the electromagnetic radiations are categorized as Non-ionizing radiations and Ionizing radiations. Non-Ionizing radiations refer to the electromagnetic radiations which have energy lower than that required for an atomic ionization (MIT, 2001). The non-ionizing radiations include radio waves, micro waves, visible light etc. These radiations have lower penetration powers. Alternatively the Ionizing radiations are the high frequency radiations which have enough energy to knockout an electron from an atom and thus causing ionization (MIT, 2001). The Gamma rays and X-rays are the common type of ionizing radiations. Even the alpha particles and beta particles emitted in a nuclear reaction are ionizing radiations (MIT, 2001). Due to the higher energy they have higher penetration power than the non-ionizing radiations. Principle of CT Scanning The most important section of a Computed Tomography (CT) scanning is the interaction of the ionizing X-ray radiations with the living tissues in the body. When the ionizing radiations (X-rays) interact with the living tissues in the body, they break up atoms and molecules from the living tissues and disrupt chemical reactions within the body (Zamanian Hardiman, 2005). The intensity of absorption of the x-ray radiations by the body varies depending upon the tissue coming in interaction. Different body tissues have different absorption power, where some are permeable to x-rays others are impermeable (Medindia, 2010). It is due to this difference in the absorption ability of different sections of the body, which results in the generation of a graded pattern in the scans. High density tissues like the bones appear white in the scan while the soft tissues (like brain and kidneys) appear dark. The cavities (like the lungs) are seen as black sections in the scan (Medindia, 2010). Therefore, this gradation in the pattern can be used as method to distinguish different body organs depending upon their absorption capacity. This forms the basic principle behind the working of an X-ray scanning. Radon (1917) was the first to develop the principles of computed tomography (CT) mathematically (Bushberg et al., 2002). According to Radon, with the help of infinite number of projections through an object, it could be possible to produce an image of an unknown object. In case of film imaging (as in conventional X-rays), a two-dimensional (2-D) projection of the body is generated on the film. Due to this, details in the dimension of the body along the direction parallel to the x-ray beam are lost. In order to overcome this drawback (only up to a certain level) projections can be taken along two directions; posteroanterior (PA) projection and lateral projection (Bushberg et al., 2002) (as shown in Figure 4). Increasing the number of scans improves the amount of information but in critical and complex cases where much more details are required. For these critical cases, CT scan is done. The CT scan provides the tomographical image, which is the picture of patients body in the sections or slabs. The thickness of these uniform slabs may vary from 1 millimeter to 10 millimeter (Bushberg et al., 2002), according to the program, depending upon the requirement. Each CT image consists of an array of large number of pixels forming a two dimensional (2-D) image, which corresponds to the same number of three dimensional thin rectangular slabs called the voxel. The voxels are the volume element whereas the pixels are the picture element (Bushberg et al., 2002). Every ray from the X-ray source passes (transmits) through the patient before the transmission measurement is done by the detector. Intensity of the un-attenuated x-ray radiation emitted by the source is Io whereas the intensity of the attenuated radiation after transmitting through the patient is given as It. The intensities Io and It are related by the equation (Bushberg et al., 2002):   Ã‚  Ã‚  Ã‚  Ã‚  It=Ioe-ÃŽ ¼t   Ã‚  Where;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚ µ is the total linear attenuation coefficient of the tissue (Smith, n.d.).   Ã‚  Ã‚  Ã‚  Ã‚  t is the distance travelled by the radiation in the tissue i.e. the tissue thickness. The coefficient  µ is dependent on the atomic number and electron density of the tissues (Smith, n.d.). Higher the atomic number and electron density of the tissues, higher would be the attenuation coefficient (Smith, n.d.). This form the basic principle of CT scanning, that different tissues have different level of attenuation properties depending upon their atomic number and electron density. For every measurement, the overall attenuation coefficient is calculated using the above equation. During a complete 360o ­ scan, various transmission measurements for the intensity of X-ray photon are done. Using these intensity measurements specific attenuation values are allotted to every voxel (volume element). These attenuation numbers are directly proportional to the linear attenuation coefficient. The average of these attenuation values is called the CT number (Smith, n.d.). These values can be arranged on a linear scale, the units of which are called the Hounsfield units (HU). The scale for modern CT scanners varies from approximately -1,000 to 3,000 HU. The attenuation scale is based on binary system and therefore the exact values range from -1,024 to +3,071, with a total of 4,096 (or 212) attenuation numbers. Here, the lower represent the black section while the higher values represent the white section of the CT image. On this scale the attenuation value of water is zero HU and that of air is -1,000 HU (Smith, n.d.). Both of these values act as the reference points. Construction of a CT scanner CT scanner is a complex machine, but the basic structure is simple. A common CT scanner has been shown in Figure 2. Two most important parts of a CT scanner are the X-ray source and detector. The source and detector are placed in a circular structure, which has a shape similar to a doughnut. This doughnut shaped circular opening is called the gantry (RadiologyInfo, 2009), with an inner (opening) diameter varying from 60 cms to 70 cms. The X-ray source and detector are placed exactly (diagonally) opposite each other, so that the radiations emitted by the source pass through the body and the transmitted radiations are measured by the detector. The x-ray source and detector system in the gantry is motorized to rotate around the patient for measurements in different projection angles. The rational speed of the system is adjusted according to the detectors ability to measure and convert the x-ray beam into electronic signal. Cobalt (60Co) is generally used as the source of x-rays in the CT scanners. The detector used in CT scanner consists of an array of detectors in a slightly curved shape (like a banana). This curved shape is especially useful in fan-shaped beam projects. Two types of detectors are generally utilized in the CT scans; solid state or scintillation detector and Xenon gas detector (Reddinger, 1997). But the solid state detectors with scintillators like Cadmium Tungstate (CdWO4), yttrium, gadolinium ceramics etc are commonly used (Bushberg et al., 2002). The principle of the scintillation detector is that, when it is struck by a x-ray photon, it produces light. This light signal is then transformed to electrical signal with the help of photodiode. The Depending upon their structure, the detectors are categorized into two categories; single detector array and multiple detector array. Another essential part of a CT scanner is the motorized examination table. The table is controlled to move in and out of the gantry during the scanning process. As the position of the x-ray source and detector is fixed therefore the section being scanned is controlled by the movement of the examination table. For a better scan it is necessary that the patient remains completely still. To insure this table is equipped with neck rest, chest board and arm pole (Cancer Research UK, 2009). The detector measures the intensity of the radiation and converts them into electrical signals. These raw signals are analyzed and manipulated by the computer to convert them into images which can be understood by the radiologists and the technicians. Multiple computers are required in a CT scanner. The main computer that controls the operation of the entire system is called the host computer (Imaginis, n.d.). The computers and controls are located in a room adjoining the scanning room. This prevents the technicians and the radiographer from exposure to x-rays. Scanning Procedure in a CT scanner Initially the patient is positioned on the examination (or scanning) table in a flat upright posture (face towards the roof). In order to insure the correct and stationary position, straps and pillows may be used along the body. Once the patient is correctly positioned on the scanning table, the motorized table moves the patient into the circular opening of the CT scanner (FDA, 2010), which the x-ray radiations are projected on the patient from the scanning. For a particular position of the x-ray source and detector, the rays from the source pass through a region called the projection or view. There are two different types of projection geometries that are used in CT scanning; parallel beam geometry and fan beam geometry. In the parallel beam geometry, the rays projected on the patient are parallel to each other whereas in fan beam geometry, the rays diverge from the source in the shape of a fan (Bushberg et al., 2002) as shown in Figure 7. The fan beam projections are the most commonly in used x-ray projections in the CT scanners. The X-ray tube is attached with a collimator which controls the thickness of the fan beam. This thickness (of the fan beam projection) determines the width of the tissue slide in the scanning process. It is through the collimator that the slice thickness is varied between 1mm to 10mm (Smith, n.d.). The x-ray source and detector rotate around the patient (for imaging) in a circular motion such that they always remain exactly (diametrically) opposite to each other (as shown in Figure 7). During the rotation the source keeps emitting x-rays which are attenuated after passing through the patient. For a single projection (or slice), the x-ray source and detector make a complete 360o rotation around the patient. During the rotation the detector takes a large number of snapshots of the absorbed X-ray beam at different projection angles. A single image may involve approximately 800 rays and there can be up to 1,000 different projection angles (Bushberg et al., 2002). Therefore for a single projection (one slice), the detector does nearly 800,000 transmission measurements (Bushberg et al., 2002). The scanning of a single projection generally takes around 1 sec (for axial CT scanners) (FDA, 2010). Once all the transmission measurements (complete 360o) for a projection (or slice) are completed, the motorized table moves along the axis of the gantry so that the next slice of tissues forms the projection view. The process is continued till the complete required section of the body has been scanned. In the traditional CT scanners, the table moved on to the next projection (slice) only when the scanning of the previous was completed. Such conventional type of scanning is called the axial scanning. But in modern CT scanners, called the helical or spiral CT scanners, the rotation of the x-ray source and detector is accompanied with the uniform movement of the examination table, thus producing a helical projection. The helical CT scanning has been shown in Figure 9. These modern helical CT scanners are much faster than the traditional scanners due to continuous scanning process. They have been reported to take nearly half the time for scanning as compared to the traditional CT scanner s. In order to analyze and study the cardiac structure which is under constant motion, even helical CT is ineffective. For such applications a special CT scanner with an exposure time of 50ms and a maximum exposure rate of 17 images per second are used (Smith, n.d.). These scanners, called the cine CT, freeze the cardiac motion due to extremely low exposure time resulting in a sharp image (Smith, n.d.). These scanners use electron beam to generate x-rays, thus are also known as Electron Beam Computed Tomography (EBCT). In the CT scanning process large volume of data and operations are required to be processed, which is achieved with the help of multiple computers. The detector converts the intensity measurements of the attenuated x-rays in to electrical signals. The main computer, called the hub computer processes these signals and converts them into an image. These images can then be analyzed for radiotherapy planning. Result Computed Tomography (CT) has become an invaluable medical tool. It provides detailed 3-D images of various sections of the body like pelvis, soft tissues, lungs brain, blood vessels and bones (Nordqvist, 2009). Generally, CT scanning is the preferred method of diagnosing different types of cancers like liver, lungs and pancreatic cancers (Nordqvist, 2009). The tomographic images produced by the CT scan provide specific location and size of the tumor along with the details of affected tissues in the proximity of the tumor. This is especially advantageous in planning, guiding, and monitoring therapies like radiotherapy (FDA, 2010). CT scanning has various benefits over other traditional diagnostic techniques; some of the benefits are (RadiologyInfo, 2009): It is non-invasive, painless and extremely accurate. A major advantage is the ability to identify and distinguish bones, soft tissues and blood vessels in the same image. It also provides real time images which cannot be done in conventional X-rays. This technique is fast and simple; and is extensively used to locate internal injuries after accidents. It is less sensitive towards patient movement as compared to MRI. CT scanning can be used on patients with medical implants unlike the MRI. For an effective radiation therapy treatment, it is necessary that only the tumor is irradiated while minimum damage occurs to the surrounding health (normal) body tissues (Badcock, 1982). This is achieved with the help of CT imaging technique. In a study by Badcock (1982), 186 patients with various malignancies were studied and it was found that in nearly 39% of the treatment cases CT scanning was valuable in the assessment of the radiationdose calculation (Badcock, 1982). According to his study, CT scanner resulted in an alternation in target dose by more than 5%, (as compared to the traditional methods) in 27% of the patients (Badcock, 1982). The result has been shown in the table below. The mean alternation was 6.5% of the target dose and usually resulted in reduction of dose per fraction by factors upto 35% (Badcock, 1982). Even with these advantages, the adverse affect of the ionizing x-ray radiations cannot be neglected. Various experiments and researches have consolidated the fact that ionizing radiations like x-rays, gamma rays etc have adverse effect on living tissues. Zamanian Hardiman (2005) have explained that when high energy ionizing radiations interact with living tissues they strip-off atoms and molecules from them. This disrupts the chemical reaction within the body and failure in organ functioning (Zamanian Hardiman, 2005). The adverse effects of ionizing radiations were seen shortly after its discovery in 1890s, with a scientist involved in the study of radioactivity were reported with skin cancer in 1902. But is was not until 1944, that the role of radiations in causing leukemia in human was first documented, mainly in radiologists and physicists (Zamanian Hardiman, 2005). In recent years the use of x-rays has extensviely increased in medical field for diagonostic and treatment application. According to the U.S. Environmental Protection Agency, X-ray deveices are the largest source of man-made radiation exposure (US_EPA, 2007). According to NCRP Report No. 160 (2006), the average annual effective dose per individual in the US population, from all sources has increase from 1.7mSv in 1980s to 6.2mSv in 2006. This increase is mainly attributed to the striking growth of high dose medical imaging procedures that utilize x-rays and radionuclides (NCRP, 2008). Such man-made devices include X-ray machines, CT scans etc. CT scans, especially result in high dose x-ray exposure, with nealy 100 times the exposure dose as compared to standard x-ray equipments (Coach, 2008). Some of the major risks associated with CT scanning are: It is well documented that ionizing radiaitons like x-rays have the ability to cause cancer on exposure. Therefore, the CT dose in radiotherapy increase the probabilty of cancer in the future. Even though only 4% of the total x-ray examinations are CT scans, they account for more than 20% of the radiation dose to the population by medical x-rays (King Saud University, 2004). In general, the effective dose in a CT scan procedure ranges from 2 mSv to 10mSv, which is nearly equivalent to the amount of radiation that a person receive from the background exposures in three to five years (RadiologyInfo, 2009). A CT scan during preganacy make cause serious illness or even birth defects in the unborn baby (FDA, 2010). Children are more sensitive and vulnerable to x-ray exposures than the adults, therefore their CT scanning should be done only under extremely essential and necessary conditions. Women have higher risk of developing cancer in the lifetime, as compared to men under same levels of exposure (FDA, 2009). In some rare situation of high-dose prolonged radiation exposure, the x-rays can cause adverse effects like skin reddening (erythema), skin tissue injury, hair loss, cataracts etc (FDA, 2010). In a study, Sawyer et al (2009) estimated the effective dose resulting from a cone beam CT scanning for planning of radiation therapy using thermoluminescent dosemeters (TLDs) for organ dose and using International Commission on Radiological Protection (ICRP) 60 tissue weighing factor (Sawyer et al., 2009). The results obtained for effective dose from TLD measurements and ICRP 60 weighting factor, for breast, pelvis and head simulation have been shown in the table below. The scanning process results in the exposure of the normal tissues outside the treatment volume (Waddington McKenzie, 2004). It is thus important to analyze the effect that the irradiation caused by the CT scanning process has on the patients body. In a study, Waddington McKenzie (2004) analyzed the propability of developing cancer from the irradiations caused by the extended field portal imaging techniques, the results of which are given in the table below (Waddington McKenzie, 2004). In order to illustrate a real life situation, the calulations in the study were done for an average man with a height of 170 cms and weight of 70 kgs (Waddington McKenzie, 2004). Therefore, these values may change depending upon the height, weight and tumor size of the patient. Discussion Various studies have been done to statistically evaluate the effect of the ionizing radiations on the human health. These risks have severely amplified due to the rapid increase in the number of CT scans for diagnostic applications. CT scans form nearly 5% of all procedures used in diagnostic radiology in the developed countries (Wrixon et al., 2004). In U.S., nearly 70 million CT scans were done in 2007 as compared to just 3 million done in 1980 (Steenhuysen, 2009), this includes more than 4 million children in 2006 (Brenner Hall, 2007). Thus, according to the NCRP Report no. 160, the average radiation dose per person has increased from 3.6 mSv in early 1980s to 6.2 mSv in 2006 (NCRP, 2008). Steenhuysen (2009) has reported that the radiations from CT scans done in 2007 will cause 29,000 cancers and kill nearly 15,000 people in America (Steenhuysen, 2009). These stats explain the level of exposure caused by the CT scans. According to estimates by Amy Berrington de Gonzalez of the National Cancer Institute,

Analysis Of Sir Gawains Character Essay -- Arthurian Legends English

Analysis Of Sir Gawain's Character In Sir Gawain and the Green Knight, the character of Sir Gawain, nephew of the famed Arthur of the Round Table, is seen as the most noble of knights who is the epitome of chivalry, yet he is also susceptible to mistakes. His courtesy, honor, honesty, and courage are subjected to various tests, posed by the wicked Morgan le Fay. Some tests prove his character and the chivalrous code true and faultless, like the time he answers a challenge although it might mean his death, or remains courteous to a lady despite temptation. Other tests prove his character and the chivalrous code faulty such as the time he breaks his promise to his host, and when he flinches from a harmless blow. The first test to his courage, courtesy, humility and loyalty toward his king, Arthur, occurs when the Green Knight suddenly appears at Camelot’s New Year's feast. He offers the Round Table a challenge: the game is for a man to strike him with his axe, and twelve months and a day later, the Green Knight will return the blow. When Arthur accepts the challenge, Gawain interferes and asks Arthur with humility and courtesy to â€Å"grant him the grace to stand by him† (SGGK l. 343-344). He confesses that â€Å"he is the weakest, and of wit feeblest, and the loss of his life would not be a great tragedy at all because his body, but for Arthur’s blood, is not worth much" (SGGK l. 354-357). He asks to be granted the privilege to claim the Green Knight's challenge because it does not befit a king. Proof of Gawain’s character is substantiated by his noble acceptance of the Green Knight’s beheading game in order to â€Å"release the king outright from his obligation†(SGGK l. 365). It shows courage and loyalty that even among famed knights suc... ...love for his life. Thus Gawain deserves less blame for his misdemeanor minor transgression. Although Gawain, like most us, is prone to evil thoughts of selfishness and dishonesty, and takes a cowardly action, "men still hold him dear" in Bercilak's castle as well as in Arthur's Camelot (SGGK l. 2465). His friends are not as disappointed with him as he is disappointed with himself. He holds himself in contempt, "rages in his heart and grieves" for the shame in his actions and the green belt that he must bear (SGGK l.251-252). He wears the girdle as a badge to remind him of his faults and to lower his pride when it becomes inflated. But he has learned from his mistakes and becomes an even better knight. Sir Gawain and the Green Knight in The Norton Anthology of English Literature 7th ed. vol.1. Abrams, M. H et al. New York: W. W. Norton & Company, 2000. 157-210.

Online Education Essay example -- School Learning Technology Computers

Online Education There is little doubt that a more extensive on-line education system would benefit extremely overcrowded campuses like Cal State Northridge. Although short-term costs may deter colleges from implementing distance learning programs initially, many colleges could save money in the long run. With the technology available, universities should make more efforts to offer more on-line classes. Distance learning is becoming more and more prevalent across campuses and is likely to continue to grow. In this paper, I will address recent criticism of the distance learning process and present material in support of this increasing phenomenon. Distance learning is taught in several ways. Originally, distance, or â€Å"Independent learning, a descendant of correspondence study, used printed materials and mail-in assignments to provide access to geographically isolated individuals† (Miller). This, however, has been replaced by on-line classes with the advent of the Internet. Mathew Mariani describes the most common approach in an article comparing an on-line course with a traditional in-classroom lecture. The material for the course is the same but it is presented via streaming video. For the on-line course, the lecture was recorded with a digital camera and downloaded by students from their personal computers. As Mariani states, â€Å"The video plays in a small window, and a slide show recreating classroom visual aids displays in a larger window. The slides advance in sync with the video lecture.† According to a study reported by Scott Dellana on performance factors, â€Å". . .courses with the on-line option have been found to be as effective as the traditional course.† Today, there are an ever-increasing number of colleges usin... ...l of General Education. Vol. 49, Issue 1: 2000. Dellana, Scott A., William H. Collins, and David West. â€Å"On-line Education in a Management Science Course-Effectiveness and Performance Factors.† Journal of Education for Business. Vol. 76, Sept 2000. Lesniak, Robert J., and Carol L. Hodes. â€Å"Social Relationships: Learner Perceptions of Interactions in Distance Learning.† Journal of General Education. Vol. 49, Issue 1: 2000. Mariani, Mathew. â€Å"Distance Learning in Post-secondary Education: Learning Whenever, Wherever.† Occupational Outlook Quarterly. Vol. 45, Issue 2: 2001. Miller, Gary E. â€Å"General Education and Distance Education: Two Channels in the New Mainstream.† Journal of General Education. Vol. 49, Issue 1: 2000. Paulson, Karen. â€Å"Reconfiguring Faculty Roles for Virtual Settings.† Journal of Higher Education. Vol. 73, Issue 1: 2002. Online Education Essay example -- School Learning Technology Computers Online Education There is little doubt that a more extensive on-line education system would benefit extremely overcrowded campuses like Cal State Northridge. Although short-term costs may deter colleges from implementing distance learning programs initially, many colleges could save money in the long run. With the technology available, universities should make more efforts to offer more on-line classes. Distance learning is becoming more and more prevalent across campuses and is likely to continue to grow. In this paper, I will address recent criticism of the distance learning process and present material in support of this increasing phenomenon. Distance learning is taught in several ways. Originally, distance, or â€Å"Independent learning, a descendant of correspondence study, used printed materials and mail-in assignments to provide access to geographically isolated individuals† (Miller). This, however, has been replaced by on-line classes with the advent of the Internet. Mathew Mariani describes the most common approach in an article comparing an on-line course with a traditional in-classroom lecture. The material for the course is the same but it is presented via streaming video. For the on-line course, the lecture was recorded with a digital camera and downloaded by students from their personal computers. As Mariani states, â€Å"The video plays in a small window, and a slide show recreating classroom visual aids displays in a larger window. The slides advance in sync with the video lecture.† According to a study reported by Scott Dellana on performance factors, â€Å". . .courses with the on-line option have been found to be as effective as the traditional course.† Today, there are an ever-increasing number of colleges usin... ...l of General Education. Vol. 49, Issue 1: 2000. Dellana, Scott A., William H. Collins, and David West. â€Å"On-line Education in a Management Science Course-Effectiveness and Performance Factors.† Journal of Education for Business. Vol. 76, Sept 2000. Lesniak, Robert J., and Carol L. Hodes. â€Å"Social Relationships: Learner Perceptions of Interactions in Distance Learning.† Journal of General Education. Vol. 49, Issue 1: 2000. Mariani, Mathew. â€Å"Distance Learning in Post-secondary Education: Learning Whenever, Wherever.† Occupational Outlook Quarterly. Vol. 45, Issue 2: 2001. Miller, Gary E. â€Å"General Education and Distance Education: Two Channels in the New Mainstream.† Journal of General Education. Vol. 49, Issue 1: 2000. Paulson, Karen. â€Å"Reconfiguring Faculty Roles for Virtual Settings.† Journal of Higher Education. Vol. 73, Issue 1: 2002.