Amount of elemental calcium in calcium solutions

There is an awareness of radiation as a possible occupational hazard and radiological investigations are frequently performed outside the main hospital radiology suite. When performing mobile X-ray examinations, all personnel should wear appropriate shielding and, whenever patient safety permits, distance themselves as far as possible from the source of radiation. The levels of scattered radiation from different mobile X-ray units have been shown to differ and the intensity of scatter of some types of beam does not decrease as rapidly as with others [1]. Exposure of groups of health care workers, e.g. orthopaedic surgeons [2] and anaesthetists [3], has been studied but the degree of exposure of nursing staff on an adult intensive care unit (ICU) is not known. Nursing staff working in an intensive care environment are repeatedly exposed to scattered radiation, chiefly from frequent diagnostic chest X-rays. It is generally assumed that the doses are very low, and consequently intensive care nurses are not included in radiation protection personnel monitoring services. In a prospective study, we monitored nursing staff on an eight-bedded general adult ICU to determine occupational exposure to radiation. Five film badge dosimeters were placed in circulation over a continuous 8-week period. The film badge employs a small piece of photographic film as the radiation detector, which becomes blackened when exposed to radiation. They have a minimum detectable dose of 0.05 mSv. The badges were worn by the nursing staff at all times, and at the end of each shift they were transferred over to the next shift nurses. The usual precautions were taken to avoid exposure from scattered radiation, which, in our unit, largely comprises ensuring a minimum `safe' distance of 2 m. It was possible to show that the period of study was typical as regards the use of X-rays. The badges indicated negligible cumulative exposure over the 8-week period. Three badges were below detectable limits; the other two badges recorded 0.05 mSv. With current working patterns of intensive care nurses and the fact that the badges were exchanged between nurses throughout three shifts per day, this can be extrapolated to indicate negligible exposure for any individual nurse over the 8-week period. Over the course of a year, an intensive care nurse would not exceed the recommended maximum whole body dose limits set by the Ionizing Radiation Regulations of 20 mSv.yr for a nonclassified radiation worker [4]. Radiographers typically receive an effective whole body dose of about 0.3 mSv.yr. For comparison, the typical patient dose from a chest X-ray is 0.02 mSv. Adherence to standard protective measures precludes most exposure to machineproduced radiation. The minimal exposures reported do not justify the regular use of dosimeters. The intensive care unit is believed to use more X-rays than other wards, so exposure elsewhere should also be undetectable. We conclude that ICU nurses can provide quality care to their patients without concerns over the detrimental effects of radiation exposure, provided that the basic principles of radiation protection are followed.