Laboratory reconstruction of personal doses in interventional radiology and cardiology

People working in interventional cardiology represent one of the most occupationally exposed groups. As recommended by the ICRP, these workers should be equipped with two personal dosemeters, one of them worn on the neck outside the protective collar and the second one on the trunk under the protective apron. It is proved that this double dosimetry method provides more precise estimate of effective dose. In connection with the new lower limit of the eye lens dose, the demands on the eye lens dose estimate increase. The aim of our experiment was to examine the relation between eye lens dose and the quantities Hp(10),Hp(3) or Hp(0.07) measured with conventional personal dosemeters worn on neck and chest. Irradiation conditions imitating the common operation of interventional radiology were created in the laboratory. The patient's body was substituted for a slab PMMA phantom (30 cm x 30 cm x 15 cm). An anthropomorphic Random phantom representing a physician was clothed in a protective apron and a collar, with equivalent of 0.5 mm Pb for both. Three personal multicomponent whole-body thermoluminescent dosemeters (TLD), which allow to measure personal dose equivalents Hp(10),Hp(3) and Hp(0.07), were fixed the Random phantom, one on the collar on the neck and two on the chest over and under the apron. The use of the third dosemeter outside the apron, beyond the recommended double dosimetry, was motivated by the fact that the double dosimetry is not preferred in the Czech Republic yet. Moreover, a special TLD called EYE-D, measuring Hp(3), was employed to determine eye lens dose. It was placed on the Random phantom's temple in the proximity of the eye closer to the radiation source. The utilized PMMA slab phantom was irradiated with X-ray source with the quality RQR5 in four typical irradiation geometries, i.e. radiation beam entered the patient from the front, back, left and right side, which was simulated by the respective arrangement of both the phantoms towards the X-ray tube. The applied air kerma value at the slab phantom's surface was 50 mGy. (authors)