适用于非参考条件的兆伏级光子束剂量学审核。

Dosimetry audit for megavoltage photon beams applied in non-reference conditions.

机构信息

Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Diagnostic Imaging and Radiotherapy Program, Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia.

Department of Radiology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.

出版信息

Phys Med. 2022 Aug;100:99-104. doi: 10.1016/j.ejmp.2022.06.011. Epub 2022 Jun 29.

DOI:10.1016/j.ejmp.2022.06.011

PMID:35779357

Abstract

PURPOSE

We have conducted for the first time a Malaysian postal dosimetry audit of external beam under non-reference conditions by evaluating the output performance while screening for systematic errors within the dosimetry chain. The potential use from the choice of detector were investigated along with the search for other sources of discrepancies.

METHODS

Ten radiotherapy centres were audited, encompassing 16 megavoltage photon beam arrangements, adopting the IAEA postal dosimetry protocol for non-reference conditions, with a holder modified to accommodate three TLD types: Ge-doped cylindrical silica fibres (CF), Ge-doped flat silica fibres (FF), and TLD-100 powder.

RESULTS

Eight of the centres operated within ± 5% of stated dose, one other exceeding tolerance for all measured points, and one did not return any dosimeters for analysis after failing the initial irradiations. Post remedial measures, the mean relative response for CF, FF, and TLD-100 was 1.00, 0.99, and 0.98 respectively, with associated coefficients of variation 6.87%, 6.45%, and 5.06%.

CONCLUSION

High quality radiotherapy clinical practice postal dosimetry audits that are based on sensitive TLDs are seen to be particularly effective in identifying and resolving dose delivery discrepancies.

摘要

目的

我们首次在非参考条件下对马来西亚的外束放射治疗进行了邮政剂量学审核，通过评估剂量链内的系统误差筛选来评估输出性能。同时还研究了探测器选择的潜在用途以及寻找其他差异来源。

方法

对 10 个放射治疗中心进行了审核，其中包括 16 种兆伏光子束布置，采用 IAEA 针对非参考条件的邮政剂量学协议，并对一个固定器进行了修改，以适应三种 TLD 类型：掺锗圆柱形二氧化硅纤维（CF）、掺锗扁平二氧化硅纤维（FF）和 TLD-100 粉末。

结果

其中 8 个中心的剂量在规定值的±5%以内，另外一个中心在所有测量点都超过了公差，还有一个中心在初始照射失败后没有返回任何剂量计进行分析。在采取补救措施后，CF、FF 和 TLD-100 的平均相对响应分别为 1.00、0.99 和 0.98，相应的变异系数分别为 6.87%、6.45%和 5.06%。