Radiation protection in medicine

Abstract

Ionizing radiation is a powerful tool in many branches of medicine, both as an aid to diagnosis and a means of therapy (treatment). The most familiar application is the diagnostic X-ray, which is used in a wide variety of examinations. Radiation can induce cancer and yet, curiously, it can also cure the disease in some cases. This is because cells which are dividing rapidly are particularly sensitive to radiation and since cancers are groups of cells dividing in an uncontrolled manner, it follows that they are often more sensitive to radiation than normal cells. There are various other conditions which can be treated by radiation but, because of the hazard involved, other methods are usually tried first. The most common method of treatment is by X-rays, but γ-rays from sealed radium, cobalt-60 or caesium-137 sources are often used. Comparatively small sealed sources may be surgically implanted in the region requiring treatment. Sealed β-ray sources such as strontium/yttrium-90 are sometimes used to irradiate the skin or eyes. Some large specialist hospitals use equipment such as cyclotrons, Van de Graaff machines or linear accelerators to produce beams of electrons or neutrons for specialized investigations and treatments.