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.

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.

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Designing and testing new equipment can be an expensive and time consuming process or the desired performance characteristics may preclude its construction due to technological shortcomings. Cost may also prevent other types of scenario being tested. An alternative is to use Monte Carlo simulations to make the investigations. This paper exemplifies how Monte Carlo code calculations can be used to fill the gap by describing two investigations: (1) the possible self-attenuation of homogeneously distributed natural uranium in a lung phantom; and (2) the effect of activity deposited in the ribs on the activity estimate from a lung count.