Department of Radiology, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada.
J Digit Imaging. 2012 Feb;25(1):189-95. doi: 10.1007/s10278-011-9390-1.
Optimization and standardization of radiographic procedures in a health region minimizes patient exposure while producing diagnostic images. This report highlights the dose variation in common computed radiography (CR) examinations throughout a large health region. The RadChex cassette was used to measure the radiation exposure at the table or wall bucky in 20 CR rooms, in seven hospitals, using CR technology from two vendors. Exposures were made to simulate patient exposure (21 cm polymethyl methacrylate) under standard conditions for each bucky: 81 kVp at 100 cm for anteroposterior abdomen table bucky exposures (180 cm for posteroanterior chest wall bucky exposures), using the left, the right, or the center automatic exposure control (AEC) cells. Protocol settings were recorded. An average of 37% variation was found between AEC chambers, with a range between 4% and 137%. A 60% difference in dose was discovered between manufacturers, which was the result of the manufacture's image processing algorithm and subsequently corrected via software updates. Finally, standardizing AEC cell selection during common chest examinations could reduce patient dose by up to 30%. In a large health region, variation in exam protocols can occur, leading to unnecessary patient dose from the same type of examination. Quality control programs must monitor exam protocols and AEC chamber calibration in CR to ensure consistent, minimal, patient dose, regardless of hospital or CR vendor. Furthermore, this report highlights the need for communication between radiologists, technologists, medical physicist, service engineers, and manufacturers required to optimize CR protocols.
在医疗区域优化和标准化放射程序可最大限度地降低患者的辐射暴露，同时生成诊断图像。本报告重点介绍了在一个大型医疗区域内，常见计算机放射摄影（CR）检查中的剂量变化。使用 RadChex 盒在七个医院的 20 个 CR 室中，在表或墙壁滤线栅上测量辐射暴露，使用来自两个供应商的 CR 技术。在标准条件下，对每个滤线栅进行模拟患者暴露（21cm 聚甲基丙烯酸甲酯）的曝光：81kVp 为 100cm（前后腹部表滤线栅曝光），180cm（前后胸部壁滤线栅曝光），使用左、右或中心自动曝光控制（AEC）单元。记录协议设置。在 AEC 室之间发现平均有 37%的变化，范围在 4%到 137%之间。制造商之间发现剂量差异高达 60%，这是由于制造商的图像处理算法造成的，随后通过软件更新进行了校正。最后，在常见的胸部检查中标准化 AEC 单元选择，可以将患者剂量降低多达 30%。在一个大型医疗区域中，检查方案可能存在差异，导致相同类型的检查产生不必要的患者剂量。质量控制计划必须监测 CR 中的检查方案和 AEC 室校准，以确保无论医院或 CR 供应商如何，都能保持一致的、最小的、患者剂量。此外，本报告强调了需要放射科医生、技术人员、医学物理学家、服务工程师和制造商之间进行沟通，以优化 CR 协议。
