Some Protection Aspects in the Planning of New Radiotherapy Departments

Abstract

The problems of radiation protection within radiotherapy departments have increased appreciably in complexity during recent years due to two major developments, namely, the introduction of new techniques which involve high energy radiation sources and unsealed radioactive materials, and increased knowledge of the long term biological effects of low doses of ionizing radiations. In consequence, radiation protection is no longer confined to the provision of an adequately shielded room to house an X-ray unit operating at about 250 kV and of protecting a few workers handling radium. Instead, it requires the provision of massive structures to house equipment operating at several MV, or containing 1,000 or more curies of a high energy γ-ray emitter such as 60Co; and of protection in laboratories, counting and dispensing rooms where smaller sources of radioactive materials are employed, and in wards and theatres where patients containing these materials are treated. Furthermore, whereas in the past the permissible levels of exposure were considered applicable to all personnel and, therefore, provided those directly employing ionizing radiations were not overexposed, the exposure of other hospital staff could be disregarded; the current recommendations give different permissible levels for various categories of worker and for the general population. It is now necessary, therefore, to consider, in addition to radiation workers, the exposure of large numbers of other hospital staff, patients other than those receiving radiation treatment, visitors and groups of the population living or working in the vicinity of the hospital.