An environmental radiation survey at the medical imaging department of a general hospital in Malta.

Abstract

Objectives The objectives of this study were to carry out an environmental radiation area survey within the medical imaging department in a general hospital in Malta, to examine whether operational radiation protection measures are adequate for workers and the general public, to measure area doses and access whether these are compatible with area designations. Methodology Evaluation of operational radiation protection measurements was achieved by using an observational checklist specifically designed for the study and based on recommendations found in 96/29/EURA TOM, the Medical and Dental Guidance Notes (Institute of Physics and Engineering in Medicine, 2002) and Facilities for Diagnostic Imaging and Interventional Radiology (NHS Estates, 2001 ). Measurement of scatter radiation from fluoroscopy was achieved by using a BICRON Ion Chamber Survey Meter which gave a reading equivalent to Instantaneous Dose Rate (IDR). From these readings, values of the Time - Averaged Dose Rate (TADR) were then calculated. Based on the IDR readings obtained and the calculated T ADR values, areas were then classified as being supervised or unsupervised. Areas where IDR readings were more than 7.5 ) μSv/h and TADR calculations were more than 0.5 μSv/h, were classified as being supervised areas. Results The observational data for the evaluation of operational radiation protection measures in the hospital under study allowed for the identification of sources of ionizing radiation, evaluation of the general facility design and additional features specific to the various types of x-ray rooms, designation of controlled/supervised areas, area monitoring, availability of personal protective apparel, personal monitoring, public radiation protection and local rules, all of which indicate that radiation protection measures are adequate. The measured IDR readings and the calculated TADR values allowed for the designation of the area behind the operating booth, the patients' changing room, the public corridor and behind the staff entry door of the fluoroscopy room under study as being non supervised areas and the bathroom in the room in question as being supervised. Dose measurements indicate that areas are appropriately designated. Conclusion It is suggested that the scope of the study be extended to other areas of the hospital concerned where ionising radiation is used.