Development of a homogeneous thick-walled graphite cylindrical ionization chamber for determination of source strength of HDR 60Co brachytherapy sources

IF 1.8 3区物理与天体物理 Q2 NUCLEAR SCIENCE & TECHNOLOGY

Radiation Measurements Pub Date : 2025-12-01 Epub Date: 2025-10-07 DOI:10.1016/j.radmeas.2025.107535

Sudhir Kumar , Rahul Kumar Chaudhary , S.D. Sharma , B.K. Sapra

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引用次数: 0

Abstract

Purpose

The source strength of brachytherapy sources should be verified prior to their clinical use. To fulfil the requirement for the standardization of high-dose rate (HDR) ⁶⁰Co brachytherapy sources, a homogeneous thick-walled graphite cylindrical ionization chamber of nominal sensitive volume 223.5 cm³ was designed, developed and established as a reference standard.

Methods

Experimental measurements were conducted with HDR ⁶⁰Co brachytherapy sources at different radiotherapy centres across India to determine the basic characteristics of this ionization chamber. The reference air-kerma rate,

{\overset{\cdot}{K}}_{R}

, of the HDR ⁶⁰Co sources was determined from the measured signal using the air-kerma calibration coefficient formalism developed earlier analytically based on Burlin general cavity theory and large cavity theory and validated with Monte-Carlo calculations.

Results

The basic characteristics of this chamber were in conformity with requirements specified in IAEA TRS-374 report. The

{\overset{\cdot}{K}}_{R}

of HDR ⁶⁰Co sources determined experimentally using this chamber was within 3 % of the

{\overset{\cdot}{K}}_{R}

value quoted by the supplier, which is traceable to PTB, Germany. The standardized HDR ⁶⁰Co sources were used for calibrating the eight well-type ionization chambers of different radiotherapy centres and the values of air-kerma calibration coefficient

N_{{\overset{\cdot}{K}}_{R}}

so obtained agreed within 3 % of the vendor-quoted values.

Conclusion

The performance of the newly developed chamber was found to be satisfactory and it qualifies to be designated as a reference standard for the measurement of

{\overset{\cdot}{K}}_{R}

of HDR ⁶⁰Co sources and for calibration of the well-type chambers of radiotherapy centres.

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一种均匀厚壁石墨圆柱形电离室的研制，用于测定HDR 60Co近距离治疗源的强度

目的近距离放射治疗源的强度在临床使用前应进行验证。为满足高剂量率（HDR） 60Co近距离放射治疗源标准化要求，设计、研制并建立了标称敏感体积为223.5 cm3的均匀厚壁石墨圆柱形电离室作为参考标准。方法利用印度不同放射治疗中心的HDR 60Co近距离放射治疗源进行实验测量，确定该电离室的基本特性。HDR 60Co源的参考空气-克尔玛率K·R由测量信号确定，采用先前基于Burlin一般腔理论和大腔理论解析开发的空气-克尔玛校准系数公式，并通过蒙特卡罗计算进行验证。结果该试验箱的基本特性符合IAEA TRS-374报告的要求。使用该实验箱实验测定的HDR 60Co源的K·R与供应商报价的K·R值相差3%以内，该供应商可追溯到德国PTB。标准化的HDR 60Co源用于校准不同放射治疗中心的8个井型电离室，由此获得的空气-克尔曼校准系数NK·R值在供应商报价的3%以内一致。结论所研制的腔体性能良好，可作为HDR 60Co源K·R测量和放疗中心井型腔体标定的参考标准。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Radiation Measurements 工程技术-核科学技术

CiteScore

4.10

自引率

20.00%

发文量

116

审稿时长

48 days

期刊介绍： The journal seeks to publish papers that present advances in the following areas: spontaneous and stimulated luminescence (including scintillating materials, thermoluminescence, and optically stimulated luminescence); electron spin resonance of natural and synthetic materials; the physics, design and performance of radiation measurements (including computational modelling such as electronic transport simulations); the novel basic aspects of radiation measurement in medical physics. Studies of energy-transfer phenomena, track physics and microdosimetry are also of interest to the journal. Applications relevant to the journal, particularly where they present novel detection techniques, novel analytical approaches or novel materials, include: personal dosimetry (including dosimetric quantities, active/electronic and passive monitoring techniques for photon, neutron and charged-particle exposures); environmental dosimetry (including methodological advances and predictive models related to radon, but generally excluding local survey results of radon where the main aim is to establish the radiation risk to populations); cosmic and high-energy radiation measurements (including dosimetry, space radiation effects, and single event upsets); dosimetry-based archaeological and Quaternary dating; dosimetry-based approaches to thermochronometry; accident and retrospective dosimetry (including activation detectors), and dosimetry and measurements related to medical applications.