Radioprotection 2024 , 59 ( 1 ), 19 – 25 © SFRP , 2024 https :// doi . org / 10.1051 / radiopro / 2023040
Available online at : www . radioprotection . org ARTICLE
Rapid assessment of dose for large-scale individual : a feasibility study
Z . Mehrabankhoo 1 , M . Behmadi 1 , 2 ,* and K . Karimi-Shahri 3 ,*
1 Medical Physics Department , Faculty of Medicine , Semnan University of Medical Sciences , Semnan , Iran . 2 Cancer Research Center , Semnan University of Medical Sciences , Semnan , Iran . 3 Physics Department , Faculty of Sciences , University of Birjand , Birjand , Iran .
Received : 27 August 2023 / Accepted : 20 November 2023
Abstract – In certain situations , it is crucial to quickly estimate the dose for radiation workers across different weight percentiles . This study sets out to create weight percentiles above 50 by adding proper adipose and muscle layers around the revised ORNL hermaphrodite phantom torso . Neutron fluence-toorgan absorbed and effective dose conversion coefficients were calculated to different weight percentiles . Simulations were performed in the energy range 10 �9 to 20 MeV , under Six different source irradiation geometries : anterior – posterior ( AP ), posterior – anterior ( PA ), right-lateral ( RLAT ), left-lateral ( LLAT ), Rotation ( ROT ), and Isotropic ( ISO ) by MCNPX code . The maximum relative differences observed between the 50 th and other percentiles ranged from 11 % to 28 %. Comparative analysis of the fluence-toabsorbed and effective dose conversion coefficients between the 95 th percentile and VIPMAN indicated that approximately 58 % and 57 % of the data had a relative difference below 15 %, respectively overall neutron energies and irradiation geometries . Our finding demonstrate that this straightforward method is reliable , especially when the whole body is irradiated in the energies above 1 MeV .
Keywords : Neutron conversion coefficients / ORNL revised phantom / weight percentiles / extra adipose and muscle layers
1 Introduction
Body shape has been recognized as a crucial factor in dosimetry , especially in radiology and radiotherapy , where accurate organ dose estimates are essential both within and outside the primary beam ( Geyer et al ., 2014 ; Johnson et al ., 2009 ; Li et al ., 2014 ). Therefore , the body shape and weigh percentiles should be closely specified . Most of these studies have focused on photon beams and the impact of body shape on neutron irradiation is not well known for external exposures . In the case of large-scale radiation incidents , such as reactor accidents and weapons detonations , there is a pressing need to estimate organ absorbed doses for a diverse range of individuals . There are various uncertainties in complex situation of nuclear accidents . However , according to the emphasis of the ICRP ( ICRP , 2020 ), every effort should be made to reduce these uncertainties . The weight percentiles can be regarded as one of the factors to consider in this regard .
* Corresponding authors : behmadim @ semums . ac . ir ; Behmadim881 . mph @ gmail . com ; k . karimi @ birjand . ac . ir ;
Monte Carlo simulations and computational human phantoms have been utilized to estimate organ absorbed doses ( Xu and Eckerman , 2010 ; Miri-Hakimabad et al ., 2009 ). However , constructing individual-specific phantoms for each exposed person belonging to various weight percentiles is impractical and time-consuming . In such situations , there is a demand for a quick a straightforward method to estimate organ absorbed doses or whole-body doses . Developing an efficient and rapid dosimetry approach is crucial to effectively assess the radiation doses received by individuals in a timely manner . This can aid in the prompt implementation of appropriate medical interventions and support the overall management of radiation accidents .
So far , researchers have made efforts to develop a simple method for constructing anthropomorphic phantoms representing different weight percentiles from existing phantoms . First , Kim et al . ( 2003 ) demonstrated that the effective dose decreased when adding a layer of soft tissue around the torso of a phantom . Their study focused on photon sources with energies of 0.08 , 0.3 , and 1 MeV . Building upon this idea , Fisher et al . ( 2014 ) constructed a 90 th percentile physical phantom based on the existing 50 th percentile model . They add