|Table of Contents|

Scatter and heterogeneity effects on dose distribution of high dose rate 192Ir brachytherapy by Monte Carlo simulation

Journal Of Modern Oncology[ISSN:1672-4992/CN:61-1415/R]

Issue:
2024 03
Page:
508-513
Research Field:
Publishing date:

Info

Title:
Scatter and heterogeneity effects on dose distribution of high dose rate 192Ir brachytherapy by Monte Carlo simulation
Author(s):
LI Lei1; CHEN Bin1; CHEN Renjin1; YANG Bo1; 2
1.Department of Oncology,the Affiliated Hospital of Southwest Medical University,Sichuan Luzhou 646000,China;2.Medicine & Engineering & Informatics Fusion and Transformation Key Laboratory of Luzhou City,Sichuan Luzhou 646000,China.
Keywords:
192Ir; brachytherapy; Monte Carlo; dosimetry
PACS:
R730.55
DOI:
10.3969/j.issn.1672-4992.2024.03.021
Abstract:
Objective:To investigate the effects of scatter and heterogeneity on dose distribution of high dose rate 192Ir brachytherapy.Methods:To simulate the TG-43 dosimetry parameters of Flexisource HDR 192Ir radioactive source by MCNP5 Monte Carlo code,which include dose rate constant Λ,radial dose function g(r) and anisotropy function F(r,θ).Simplified models of body circumference difference,tumor on side of body,superficial radiotherapy,tissue component difference,lung implantation and luminal implantation were modeled based on clinic.The radial dose distribution of radioactive sources was calculated respectively.The effects of scatter and heterogeneity on dose distribution were evaluated by comparing the deviations of doseat the same point as the standard model.Results:The deviation between MC values of TG-43 dosimetry parameters and TPS datas was less than 1%.Insufficient scattering:TPS would overestimate real dose at 2 cm,5 cm and 10 cm about 4%,14.8% and 16.4%.Cortical bone:TPS would overestimate real dose at 2 cm,5 cm and 10 cm about 0.7%,1.14% and 10%.Tumor tissue:TPS would overestimate real dose by an average of 1.1%.Lung:TPS would overestimate real dose of 0.5 cm to 6 cm by an average of 1.8%,and underestimate real dose of 6 cm to 15 cm by an average of 7.77%.Lung implantation:TPS would overestimate real dose of 0.5 cm to 8 cm by an average of 4%,and underestimate real dose of 8 cm to 15 cm by an average of 7.8%.Luminal implantation:for 1 mm,4 mm and 8 mm radius air cavity,TPS underestimated real dose about 0.75%,1.30% and 2.48% on average.Conclusion:Ignoring scatter and heterogeneity can lead to significant errors in dose delivered to patients.It is necessary to correct the real dose delivered to patients in clinic.

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四川省科技计划项目（编号:2020JDTD0036）;医工医信融合与转化医学泸州市重点实验室项目（编号:XGY202105）;四川省医学科研课题计划（编号:S19007）
Last Update: 2023-12-29