Many of us are aware of the widespread use of radiation in the medical community. It can be used for diagnosis as well as therapy for a number of diseases.
In diagnostic treatments, x-rays can provide images for identifying abnormal changes in body organs and tissues. With advanced imaging and computing technologies, a three dimensional picture or animation can be generated to facilitate the diagnostic treatment if radioisotopes are injected or ingested into the patient. The most widely used diagnostic radioisotope is technetium-99m which has a half-life of six hours and releases g rays during radioactive decay. While giving the patient a very low radiation dose, technetium-99m allows sufficient time for the diagnosis process.
In therapy treatments, a radioisotope of iodine, iodine-131, is used to treat thyroid cancer. For some cancers, g rays from cobalt-60 sources are used to destroy cancer cells. Irradiating a tumour with ionizing radiation has proved to be effective in inhibiting the tumour's growth or even destroying it.
Nowadays, many medical utensils are sterilized by g rays from cobalt-60 sources. This technique is much cheaper and more effective than steam sterilization. Disposable syringe, cotton wool and surgical consumable are good examples. Since it is not a high temperature treatment process, it can be used to sterilize a range of heat-sensitive items such as plastics. In addition, as g rays have very high penetrating power, the sterilization process can be done after the item is packaged. This ensures that the item is free from bacteria before being used.
Since the discovery of anthrax-laden mail in US in October 2001, US Government uses x-rays in the same manner as in medical usage to sterilize suspected items sent through mail to avoid panic in the country.
Different types of radioactive medical instruments
(Source:Hong Kong Baptist Hospital )