Development of PIMAL: Mathematical Phantom with Moving Arms and Legs

Technical Report · Tue May 01 04:00:00 EDT 2007

DOI:https://doi.org/10.2172/1339944· OSTI ID:1339944

Akkurt, Hatice ^[1]; Eckerman, Keith F. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The computational model of the human anatomy (phantom) has gone through many revisions since its initial development in the 1970s. The computational phantom model currently used by the Nuclear Regulatory Commission (NRC) is based on a model published in 1974. Hence, the phantom model used by the NRC staff was missing some organs (e.g., neck, esophagus) and tissues. Further, locations of some organs were inappropriate (e.g., thyroid).Moreover, all the computational phantoms were assumed to be in the vertical-upright position. However, many occupational radiation exposures occur with the worker in other positions. In the first phase of this work, updates on the computational phantom models were reviewed and a revised phantom model, which includes the updates for the relevant organs and compositions, was identified. This revised model was adopted as the starting point for this development work, and hence a series of radiation transport computations, using the Monte Carlo code MCNP5, was performed. The computational results were compared against values reported by the International Commission on Radiation Protection (ICRP) in Publication 74. For some of the organs (e.g., thyroid), there were discrepancies between the computed values and the results reported in ICRP-74. The reasons behind these discrepancies have been investigated and are discussed in this report.Additionally, sensitivity computations were performed to determine the sensitivity of the organ doses for certain parameters, including composition and cross sections used in the simulations. To assess the dose for more realistic exposure configurations, the phantom model was revised to enable flexible positioning of the arms and legs. Furthermore, to reduce the user time for analyses, a graphical user interface (GUI) was developed. The GUI can be used to visualize the positioning of the arms and legs as desired posture is achieved to generate the input file, invoke the computations, and extract the organ dose values from the MCNP5 output file. In this report, the main features of the phantom model with moving arms and legs and user interface are described.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; Nuclear Regulatory Commission (NRC) (United States). Office of Nuclear Regulatory Research
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1339944
• Report Number(s): ORNL/TM--2007/14
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING