Review of Related Literature
The review of related literature in this chapter is composed of principles and discussions of facts about the side effects of radiation therapy to the cancer patients. The chapter begins with a brief history about radiology as a medical science, and radiation therapy as a form of medical treatment of diseases. Lastly it enumerates the side effects of radiation therapy and the risks associated with it. Brief History and Definitions of Radiology as a Medical Science In 1895 Roentgen began experiments at the University of Würzburg with an electric current flow in a partially evacuated glass tube known as a cathode-ray tube. He noticed that, whenever the tube was in operation, a piece of barium platino cyanide in line with it gave off light. According to Roentgen “the interaction of electrons striking the tube's glass wall formed an unknown radiation that caused the fluorescence”. He called the mysterious phenomenon X radiation, or X rays. Further experiments revealed that X radiation produces an image on photographic plates and penetrates many materials such as paper, wood, certain metals, and living tissue. For the first time physicians had a nonsurgical tool to see inside the body. (Source: http://www.northhertsradiologygroup.co.uk/history.html) Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. It is the performance of medical procedures with the guidance of imaging technologies. According to Medilexicon's medical dictionary, “Radiology is the science of high energy radiation and of the sources and the chemical, physical and biologic effects of such radiation”
The acquisition of medical imaging is usually carried out by the radiographer or radiologic technologist. Radiographers are responsible for using complex and highly sophisticated equipment such as X-ray radiography, ultrasound, computed tomography (CT), nuclear medicine, positron emission tomography (PET) and magnetic resonance imaging (MRI) to produce image that are used by radiologists to diagnose the extent of disease or injury. They take roentgen photographs of the body's internal structures and treat abnormalities with radiation. These images may be displayed on X-ray film, movie film, videotape, television monitors or computer read-outs for the well-being of patients during their investigation or treatment. The radiologist are specialized medical practitioners, who diagnose and treat diseases using radiant energies such as X-rays, ultrasound, gamma rays and radio waves and interprets or reads the images and produces a report of their findings or impressions and diagnosis. This report is then transmitted to the ordering physician, either routinely or emergently. Radiation Therapy as a Form of Medical Treatment of Diseases
Radiation therapy is a type of cancer treatment that uses beams of intense energy to kill cancer cells. Radiation therapy most often gets its power from X-rays, but the power can also come from protons or other types of energy. The term "radiation therapy" most often refers to external beam radiation therapy. During this type of radiation, the high-energy beams come from a machine outside of your body that aims the beams at a precise point on your body. During a different type of radiation treatment, radiation is placed inside your body. Radiation therapy commonly applied to the cancerous tumor by destroying the genetic material that controls how cells grow and divide. The radiation fields may also include the draining lymph nodes if they are clinically or radiologically involved with tumor, or if there is thought to be a risk of subclinical malignant spread. It is necessary to include a margin of normal tissue around the tumor to allow for uncertainties in daily set-up and internal tumor motion. These uncertainties can be caused by internal movement and movement of external skin marks relative to the tumor...