Uses Of Radioactivity In Medicine Essay Research

Uses Of Radioactivity In Medicine Essay, Research Paper

Uses of radioactivity in medicine

Introduction

Radiation is a potent cause of cancer. Radiation causes changes in DNA, including breaks in the chromosomes (the tiny structures in cells that contain DNA) and chromosome transpositions the exchange of chromosomal material between two chromosomes. Radiation causes a normal cell to slowly become cancerous over a period of years. During this period, the cell may be more susceptible to other cancer-causing factors. The most common sources of radiation include the ultraviolet B rays of the sun, which cause over 90 percent of all skin cancers, and radon gas, which is emitted from the earth and seeps into buildings sometimes collecting in high levels. Breathing high levels of radon gas for long periods of time may cause lung cancer. However, when used correctly, radiation can help to remove or reduce the effects of existing cancers.

Treatment

Radiation therapy uses powerful x-rays (produced when a beam of electrons strikes a heavy-metal target) or gamma rays (emitted by radioactive decay) to destroy cancerous tissue. Tumors easily reached with a source of radiation either a beam of radiation or through tiny radioactive implants may be cured by radiation therapy.

Radiation therapy is useful when a tumor is located where it cannot be surgically removed because surgery would damage vital adjacent tissue or because a tumor has begun to grow in adjacent tissues or organs that cannot be removed. Radiation therapy is also used to reduce the effects of cancer, especially of metastatic tumors.

Radiation can also be used before surgery to sterilize tumor cells and prevent them from spreading to other parts of the body during surgery. Radiation may shrink the tumor and make surgery easier, or shrink an inoperable tumor to an operable size. For other tumors radiation may be used following surgery. New techniques in radiation therapy now allow tumors to be precisely targeted by a beam of radiation, eliminating damage to healthy surrounding tissues. These techniques are known as conformal radiotherapy because the radiation beam conforms to the shape of the tumor.

Radiology

In medicine, radiology is the discipline of medical science that uses electromagnetic radiation and ultrasonics for the diagnosis and treatment of injury and disease.

Radiology originated with the discovery of X rays by German physicist Wilhelm Conrad Roentgen in 1895. Roentgen was awarded the first Nobel Prize in physics (1901) for his work.

Diagnostic Radiology

Diagnostic radiology, or diagnostic imaging, is the medical evaluation of body tissues and functions both normal anatomy and physiology and abnormalities caused by disease or injury by means of static (still) or dynamic (moving) radiologic images.

In the century since Roentgen s discovery, electromagnetic radiation in the form of ionizing radiation (alpha, beta, gamma, and X rays) has been the predominant energy source for diagnostic radiology.

The use of ionizing radiation in diagnostic radiology involves passing a localized beam of X rays through the part of the body being examined. This produces a static image on film. The image, called a radiograph, or X-ray picture, can take several forms. It may be a plain radiograph, such as the common chest X ray; a mammogram, an X-ray image of the female breast used to scan for cancerous tumors; a tomograph, which produces an image of the entire depth of an anatomical structure with a series of X rays; or a computerized axial tomography (CT or CAT) scan, a computer analysis of a cross-sectional image of the body.

Many organs, organ systems, and certain muscular and skeletal structures are not visible with routine radiographic techniques. They become visible with the ingestion, injection, or inhalation of substances called contrast media, which are opaque to radiation. Diagnostic techniques involving contrast media include the upper gastrointestinal (GI) series, barium enema (colon examination), arthrogram (injection of contrast into a joint), myelogram (injection of contrast into the spinal canal), and angiogram (injection of contrast into an artery, vein, or lymph vessel).

Dynamic images, which record movement of organs or organ systems such as the intestinal tract or the flow of contrast material through blood vessels or the spinal canal, may be obtained by fluoroscopy (recording the radiographic image on a movable, radiation-sensitive screen) or cineradiography (recording the image on film or videotape). Both film and videotape are permanent recording media. The fluoroscopic image, analogous to a television image, is transient. Permanent radiographic images (spot films) can, however, be made at any time during a fluoroscopic examination. Another type of diagnostic imaging that identifies biochemical activity in addition to structural tissues is positron emission tomography (PET). In this method, a patient is injected with glucose treated with radioactive tracers. As the body metabolizes the glucose, the PET scan monitors the radioactive particles emitted by the tracers in the glucose. Images are produced that show metabolic reactions, making this method useful to diagnose brain tumors and strokes.

The use of ionizing radiation in the evaluation of disease is similar to the

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