Implementing a Phase II Quality Control Protocol for a High Precision 137 Cs Dosimetry Calibration Irradiator.

IF 1 4区 医学 Q4 ENVIRONMENTAL SCIENCES
Health physics Pub Date : 2025-01-01 Epub Date: 2024-09-27 DOI:10.1097/HP.0000000000001885
Jordan D Noey, Colin J Stewart, Kimberlee J Kearfott
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引用次数: 0

Abstract

Abstract: In medical physics, rigorous quality assurance and quality control protocols are vital for precise dose delivery applications. In many health physics applications, the allowable uncertainty for various processes is often greater than that of medical physics due to looser safety ties. This results in less demand for quality control and uncertainty analyses, since these may not be needed. However, certain applications can benefit from a comprehensive quality control program, as it may yield important insights, such as air kerma monitoring in dosimetry calibrations for environmental and low-dose applications. By implementing a thorough quality control program tailored to specific contexts and needs, uncertainties associated with dose measurements can be quantified with greater accuracy and reliability. This proactive approach not only ensures the integrity of data collected but also enhances understanding of the measured doses. For these reasons, a comprehensive quality control initiative was implemented following documented failures in a 137 Cs dosimetry calibration irradiator. This involved systematic charge collection using NIST-traceable ion chambers to observe long-term changes. A Phase I quality control protocol was previously implemented, which employed Shewhart control charts and Nelson's rules to analyze various datasets subgrouped under different conditions. This study addresses the development of a Phase II protocol, which focuses more on uncertainty quantification of systematic errors and irradiator changes, and air kerma precision for dosimetry calibrations. A designed experiment was performed to identify how much systematic errors influence the air kerma. Emphasis was placed on stricter quality assurance protocols, continuous data collection, and additional control charts to monitor short-term changes, such as exponentially weighted moving average control charts. A pre-irradiation control process was implemented to verify that the total air kerma met the measurement quality objective and to show how various uncertainties were applied before calibration. This study indicates how uncertainty is applied given observed air kerma measurements from the irradiator. Ongoing efforts aim to streamline the quality control procedure, ensure consistent data collection, and assess its impact on dosimetry applications.

为高精度 137Cs 剂量测定校准辐照装置实施第二阶段质量控制规程。
摘要:在医学物理学中,严格的质量保证和质量控制规程对于精确的剂量输送应用至关重要。在许多健康物理学应用中,由于安全约束较松,各种过程的允许不确定性往往大于医学物理学。这导致对质量控制和不确定性分析的需求减少,因为可能不需要这些分析。不过,某些应用可以从全面的质量控制计划中获益,因为它可能会产生重要的见解,例如在环境和低剂量应用的剂量测定校准中进行空气热玛监测。通过针对具体情况和需求实施全面的质量控制计划,可以更准确、更可靠地量化与剂量测量相关的不确定性。这种积极主动的方法不仅能确保所收集数据的完整性,还能加深对测量剂量的理解。因此,在 137Cs 剂量测定校准辐照装置出现有记录的故障后,实施了一项全面的质量控制措施。这包括使用 NIST 可追溯离子室系统地收集电荷,以观察长期变化。之前实施的第一阶段质量控制规程采用了 Shewhart 控制图和 Nelson 规则来分析在不同条件下分组的各种数据集。本研究旨在制定第二阶段方案,该方案更侧重于系统误差和辐照装置变化的不确定性量化,以及剂量测定校准的空气开玛精度。通过设计实验来确定系统误差对空气压模的影响程度。重点放在更严格的质量保证协议、连续的数据收集和监测短期变化的附加控制图上,如指数加权移动平均控制图。实施了辐照前控制流程,以验证总空气热辐射符合测量质量目标,并显示校准前如何应用各种不确定性。这项研究表明,在观测到辐照装置的空气热尔马测量结果时,是如何应用不确定性的。目前正在努力简化质量控制程序,确保数据收集的一致性,并评估其对剂量测定应用的影响。
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
Health physics
Health physics 医学-公共卫生、环境卫生与职业卫生
CiteScore
4.20
自引率
0.00%
发文量
324
审稿时长
3-8 weeks
期刊介绍: Health Physics, first published in 1958, provides the latest research to a wide variety of radiation safety professionals including health physicists, nuclear chemists, medical physicists, and radiation safety officers with interests in nuclear and radiation science. The Journal allows professionals in these and other disciplines in science and engineering to stay on the cutting edge of scientific and technological advances in the field of radiation safety. The Journal publishes original papers, technical notes, articles on advances in practical applications, editorials, and correspondence. Journal articles report on the latest findings in theoretical, practical, and applied disciplines of epidemiology and radiation effects, radiation biology and radiation science, radiation ecology, and related fields.
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