診療用放射線による患者被ばく

All medical exposures should be justified (more benefit than risk). This requires not only knowledge of medicine but also of the radiation risks. The magnitude of risk from radiation is dose-related with higher amounts of radiation being associated with higher risks. The aim of managing radiation exposure is to minimise the putative risk without sacrificing, or unduly limiting, the obvious benefits in the prevention, diagnosis and also in effective cure of diseases (optimization). Various diagnostic radiology procedures cover a wide dose range based upon the procedure. There may be a wide variation in the dose given for the same procedure on a specific individual when performed at different facilities. This variation may be up to a factor of ten and is often due to differences in the technical factors for the procedure. Interventional Radiology is increasingly used by practitioners in many specialties to reduce morbidity and mortality. However, there is a growing literature on serious skin injuries to patients from IVR procedures. The frequency of CT examinations is also increasing rapidly. The absorbed dose to tissues from CT can often approach or exceed the levels known to increase the probability of cancer as shown in epidemiological studies. Especially both the fetus and children are thought to be more radiosensitive than adults. Diagnostic radiology is extremely unlikely to result in doses that cause malformations or a decrease in intellectual function. The main issue following in-utero or childhood exposure at typical diagnostic levels (<50 mGy) is cancer induction. Now diagnostic reference levels can be used to help manage the radiation dose to patients so that the dose is commensurate with the clinical purpose. Appropriate equipment and training are needed to minimize this risk. Patient counseling should be undertaken routinely, and follow up when appropriate.