ABSTRACT
Ring dosimeters for personal dosimetry are calibrated in accredited laboratories following ISO 4037-3 guidelines. The simultaneous irradiation of multiple dosimeters would save time, but has to be carefully studied, since the scattering conditions could change and influence the absorbed dose in nearby dosimeters. Monte Carlo simulations using PENELOPE-2014 were performed to explore the need to increase the uncertainty ofHp0.07in the simultaneous irradiation of three and five DXT-RAD 707H-2 (Thermo Scientific) ring dosimeters with beam qualities: N-30, N-80 and N-300. Results show that the absorbed dose in each dosimeter is compatible with each of the others and with the reference simulation (a single dosimeter), with a coverage probability of 95% (k= 2). Comparison with experimental data yielded consistent results with the same coverage probability. Therefore, five ring dosimeters can be simultaneously irradiated with beam qualities ranging, at least, between N-30 and N-300 with a negligible impact on the uncertainty ofHp0.07.
Subject(s)
Radiation Dosimeters , Radiometry , Calibration , Computer Simulation , Monte Carlo MethodABSTRACT
Measurements of eye lens dose using over apron dosimeters with a geometric correction factor is an international accepted practice. However, further knowledge regarding geometric correction factors in different contexts is required. The authors studied the correlation between eye lens dose and over apron dosimetry for different medical specialties in eleven hospitals, using a standardized protocol, two independent over apron dosimeters (worn at chest and at neck levels) and a dedicated calibration procedure. The results show good correlation between subjects working on the same medical specialty for 5 specialties: Interventional Radiology, Vascular Surgery, Vascular Radiology, Hemodynamics and Neuroradiology. The geometric correction factors resulting from this study could be used to estimate eye lens dose using over apron dosimeters, which are more comfortable than eye lens dosimeters, as reported by the study subjects, as long as the increased uncertainty of the over apron dosimetry compared to the dedicated eye lens dosimetry is acceptable.
Subject(s)
Lens, Crystalline , Occupational Exposure , Radiation Protection , Humans , Occupational Exposure/analysis , Protective Clothing , Radiation Dosage , Radiology, InterventionalABSTRACT
OBJECTIVE: Re-evaluate the effective dose (E) of typical nuclear medicine procedures using the new ICRP-103 weighting factors and the latest dosimetry data and relate E with Background Equivalent Radiation Time (BERT). MATERIAL AND METHODS: Effective dose associated with radiopharmaceuticals and nuclear medicine procedures has been calculated for the following ages: adult, 15, 10, 5 and 1 year. Dosimetry data have been extracted from ICRP-106, ICRP-80, ICRP-53 and/or manufacturer's brochure. RESULTS: The relationship of the data of effective dose associated with radiopharmaceuticals and explorations is shown. The new tissue weighting factors result in a decreased value of the effective dose, except in cases that particularly affect the breast, in which it increases. The effective dose associated with nuclear medicine procedures is in the range 0.1-60 mSv. BERT ranges from a few days to 20 years. The effective dose associated to tests in children is generally higher than the effective dose for an adult. CONCLUSIONS: The results shown in this paper are an updated collection of effective dose values for commonly used radiopharmaceuticals in nuclear medicine. Expressing the effective dose equivalent time in units of natural radiation helps to explain issues associated with radiation exposure to patients and healthcare personnel.
