Imprimir Resumo


Teste
Abstract: 135-1

135-1

DoseCV - a program to convert the absorbed dose of MRCP phantoms into simulations carried out in MCNP

Authors:
Válter José Coutinho Júnior (PPGEB/FEELT/UFU - Programa de Pós-graduação em Engenharia Biomédica, Faculdade de Engenharia Elétrica, Universidade Federal de Uberlândia, INFIS/UFU - Instituto de Física - Universidade Federal de Uberlândia) ; Willian Kenji Silva Nakano (INFIS/UFU - Instituto de Física - Universidade Federal de Uberlândia) ; Ana Paula Perini (PPGEB/FEELT/UFU - Programa de Pós-graduação em Engenharia Biomédica, Faculdade de Engenharia Elétrica, Universidade Federal de Uberlândia, INFIS/UFU - Instituto de Física - Universidade Federal de Uberlândia) ; Lucio Pereira Neves (PPGEB/FEELT/UFU - Programa de Pós-graduação em Engenharia Biomédica, Faculdade de Engenharia Elétrica, Universidade Federal de Uberlândia, INFIS/UFU - Instituto de Física - Universidade Federal de Uberlândia)

Abstract:

The resolution of computer phantoms has increased over the years, thereby more reliably reproducing the human body. The ICRP Publication 145 mesh reference computational phantoms (MRCPs) are an evolution of the ICRP Publication 110 phantoms, and are now available in polygon meshes [1]. Analyzing MCNP simulation results using these phantoms can be time consuming and error prone owing to the amount of data and various calculations that need to be performed to obtain the dose coefficient (DC) for a given organ. It is necessary to combine the tally values to obtain the dose absorbed by a given organ considering the weight of each tissue. Next, it is necessary to consider variables such as the area of the radiation beam and perform unit conversion. The calculation of DCs for the remaining tissues and skeletal target tissues presents peculiarities. Both the male and female phantoms feature 119 structures that represent organs and tissues. This article proposes the creation of a software called DoseCV to help process the output data from MCNP simulations. POLY2TET software was used to tetrahedralize the phantoms and create a standard simulation scenario equivalent to those in Publications 116 and 145 [2]. The use of POLY2TET was validated by obtaining dose-equivalent data to that in the presentation article. For a photon and electron beam with 10 MeV energy, Han et al. obtained DCs values of 22.30 and 56.1 (pGy.cm²) in the liver, respectively [2]. The results obtained by DoseCV were 22.90 and 58.78 (pGy.cm²) respectively. The difference between the two results must be associated with the history cuttof (nps) defined for each simulation in the MCNP. The DCs values found for MRCPs in Publication 145 were similar or even equal to those found in Publication 116 for most tissues [3]. As Publication 145 presents the DCs values in graphs, we compared the numerical data obtained in the simulations with those in Publication 116. Comparing the DCs values (pGy.cm²) of Publication 116 for the target tissues of the MRCP-Adult Female phantom exposed to a 10 MeV photon monoenergetic beam and the values obtained by DoseCV, we obtained the greatest difference in the urinary bladder (8.04%), with 20.00 and 21.75 (pGy.cm²), respectively. The smallest difference was in the stomach (0.13%), presenting a dose coefficient of 22.7 and 22.73 (pGy.cm²). In its first version, DoseCV converts tally data into DCs, allowing the simulation to be validated by comparing it with Publications 116 and 145. DoseCV proved to be an effective tool for processing data from MCNP simulations.

Acknowledgments

The authors would like to thank the Brazilian agencies CNPq (Grants 312160/2023-2 (L.P.N), 312124/2021-0 (A.P.P), 309675/2021-9 (W.S.S) and 406303/2022-3) and FAPEMIG (Grants APQ-04215-22, APQ-01254-23 and APQ-04348-23).

Keywords:
 MCNP, MRCP, numeric dosimetry, phyton