This work provides the results of a collaboration between the Human Monitoring Laboratory (HML) and the Centre Hospitalier de l'Université de Montréal (CHUM) in which CHUM provided CT lung image sets from 166 patients for the analysis of linear dimensions and lung volume. This work has shown that a large amount of data exists in the medical community that can be of value to the health physics community. The intent of this study was to determine the range of linear dimensional parameters that could be used for torso phantom development for males and females; understand and characterize the variability of linear lung dimensions for males and females; replace the brief table in ICRP 23 with more modern data for males and females; identify an empirical formula that would predict linear dimensions of human lungs from age, height and/or weight for males and females; characterize the left, right, and total lung volumes of males and females in this data set; and compare the lung volumes of males and females to published equations for determining lung volumes. It was found that linear dimensions of lungs are essentially independent of age, height, and weight, so predictive equations cannot be formulated; however, the ranges of those parameters have now been established for the population studied herein. The data presented here are more modern than the brief table that appeared in ICRP 23, and the average values could be used as future guidelines. Whole lung volumes have been determined from the voxel lung phantoms, and empirical formulae have been developed for males and females in this data set; these compare favorably with the published values in ICRP 66.
A joint project between the Human Monitoring Laboratory (HML) and the Ottawa Hospital has measured the retention of 131I in patients who have received the radioiodine diagnostically. Thirty-nine subjects with intact thyroid glands and nine athyreotic subjects were measured in the HML's whole-body/thyroid counter to determine the retention of 131I following its medical administration. The average biological half-life of 131I in 26 euthyroid subjects was found to be 66.1+/-6.3 days which may he statistically significantly lower than the ICRP recommended value of 80 days. Nine hyperthyroid patients had a mean biological half-life of 38.2+/-8.6 days and in three hypothyroid patients the corresponding value was 29.3+/-8.8 days. Thyroid 131I uptake was measured in a conventional clinical fashion at the Ottawa Hospital Civic campus 24 h after oral administration of the radioiodine using a collimated thick sodium iodide detector placed over the neck anteriorly. Measured values were 10.144+/-0.009, 0.314+/-0.035 and 0.045+/-0.010 of the administered dose in euthyroid, hyperthyroid and hypothyroid patients respectively. The euthyroid range at the hospital is 0.06 - 0.22. Uptake was significantly lower for the euthyroid group than the ICRP value of 0.3. The radioiodine retention in athyreotic subjects followed a two compartment model with biological half-lives of 1.0+/-1.2 days and 18.4+/-1.1 days.
The Human Monitoring Laboratory (HML) has used the International Commission on Radiological Protection's Report on Reference Man and Canadian anthropomorphic data as guidance to design and construct a family of phantoms corresponding to Reference Man (PM), Reference Woman (PF), Reference Ten-Year-Old (P10), Reference Four-Year-Old (P4), Ninety-five Percentile Man (PM95), and Five Percentile Man (PM5). The PM series also has an accessory chest section (PMacc) to better simulate lung depositions. The phantoms are constructed from high-density polyethylene and fitted with end-recessed filling caps to minimize leakage problems. This paper describes the methodology of construction and presents data so that the phantoms can be reproduced. The phantoms have been used in Canada's National in-vivo Intercomparison Program, and results show that all Canadian in-vivo counting facilities have size-dependent calibrations. Selected data are presented to exemplify this dependence.
Monte Carlo simulation has been used to model the Human Monitoring Laboratory's scanning detector whole body counter. This paper has also shown that a scanning detector counting system can be satisfactorily simulated by putting the detector in different places relative to the phantom and averaging the results. This technique was verified by experimental work that obtained an agreement of 96% between scanning and averaging. The BOMAB phantom family in use at the Human Monitoring Laboratory was also modeled so that both counting efficiency and size correction factors could be estimated. It was found that the size correction factors lie in the region of 2.4 to 0.66 depending on phantom size and photon energy. The efficiency results from the MCNP scanning simulations were 97% of the measured scanning efficiency. A single function that fits counting efficiency, size, and photon energy was also developed. The function gives predicted efficiencies that are in the range of +10% to -8% of the true value.
Following a radiation emergency, the affected public and the first responders may need to be quickly assessed for internal contamination by the radionuclides involved. Urine bioassay is one of the most commonly used methods for assessing radionuclide intake and radiation dose. This paper attempts to derive the sensitivity requirements (from inhalation exposure) for the urine bioassay techniques for the top 10 high-risk radionuclides that might be used in a terrorist attack. The requirements are based on a proposed reference dose to adults of 0.1 Sv (CED, committed effective dose). In addition, requirements related to sample turnaround time and field deployability of the assay techniques are also discussed. A review of currently available assay techniques summarized in this paper reveals that method development for ²⁴¹Am, ²²⁶Ra, ²³⁸Pu, and ⁹⁰Sr urine bioassay is needed.
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