醫療輻射曝露診斷參考水平的建立與使用

Establishment and Application of Diagnostic Reference Levels of Medical Radiation Exposures

在放射診斷的領域中，醫療輻射曝露診斷參考水平是在檢查條件最佳化過程中的重要工具。醫療輻射曝露診斷參考水平可分為國家診斷參考水平及機構診斷參考水平，其中國家診斷參考水平是在大規模調查中針對標準體型受檢者而建立，是啓動最佳化的第一步；而機構診斷參考水平則能藉由每年定期審視檢查劑量，更有效率地改善檢查方式。若是機構的劑量經定期審視發現其高於診斷參考水平，則應檢視其檢查流程，檢討造成劑量偏高的原因，並採取修正措施。本報告之主要目的為彙整國際現況，並對建立與使用國家與機構診斷參考水平提出建議。在方法上，主要參考英國醫學物理與工程學會第88 號報告，並依據國內實際應用之情況，針對乳房攝影及電腦斷層設備作較詳盡之闡述。此外，本報告並提供國內醫療輻射曝露診斷參考水平應用之範例，包含建立乳房攝影國家診斷參考水平，以及範例醫院之電腦斷層掃描機構參考劑量水平。

Diagnostic reference level (DRL) of medical radiation exposure is one of the most important tools for the optimization of imaging protocols in diagnostic radiology. DRL of medical radiation exposure can be categorized into the national DRL (NDRL) and the local DRL (LDRL). NDRL is established based on average-sized patient data derived from large scale surveys and triggers the first step in the optimization process, whereas LDRL may improves the imaging exams more efficiently by reviewing the corresponding dose levels annually. Based on periodic audits, if the patient doses are higher than the established DRLs, the institution shall review the examination procedures, investigate the causes, and take corrective actions. This task group report aimed to summarize the current international status, and to provide recommendations of establishments and applications of the NDRL and the LDRL. The methodology in this report largely referenced the report No. 88 of Institute to Physics and Engineering in Medicine (IPEM), UK, with more details added specifically for mammography and computed tomography (CT) according to the current situations in Taiwan. In addition, this report provided practical examples on applications of DRLs in Taiwan, including establishing NDRL for mammography and the use of LDRL in a sample hospital.