Murray J G, Dowsett D J, Laird O, Ennis J T
Eccles Street Breast Screening Centre, Mater Misericordiae Hospital, Dublin, Ireland.
Br J Radiol. 1992 Dec;65(780):1097-101. doi: 10.1259/0007-1285-65-780-1097.
In contrast to the majority of mammographic breast screening programmes, film processing at this centre occurs on site in both hospital and mobile trailer units. Initial (1989) quality control (QC) sensitometric tests revealed a large variation in film processor performance in the mobile unit. The clinical significance of these variations was assessed and acceptance limits for processor performance determined. Abnormal mammograms were used as reference material and copied using high definition 35 mm film over a range of exposure settings. The copies were than matched with QC film density variation from the mobile unit. All films were subsequently ranked for spatial and contrast resolution. Optimal values for processing time of 2 min (equivalent to film transit time 3 min and developer time 46 s) and temperature of 36 degrees C were obtained. The widespread anomaly of reporting film transit time as processing time is highlighted. Use of mammogram copies as a means of measuring the influence of film processor variation is advocated. Careful monitoring of the mobile unit film processor performance has produced stable quality comparable with the hospital based unit. The advantages of on site film processing are outlined. The addition of a sensitometric step wedge to all mammography film stock as a means of assessing image quality is recommended.
与大多数乳腺钼靶筛查项目不同的是，该中心的胶片冲洗在医院和移动拖车单元均在现场进行。最初（1989年）的质量控制（QC）感光测定测试显示，移动单元中胶片冲洗机的性能存在很大差异。评估了这些差异的临床意义，并确定了冲洗机性能的验收限度。将异常的乳房X光片用作参考材料，并在一系列曝光设置下使用高清晰度35毫米胶片进行复制。然后将这些复制品与移动单元的QC胶片密度变化进行匹配。随后对所有胶片的空间分辨率和对比度分辨率进行排序。得出冲洗时间的最佳值为2分钟（相当于胶片传输时间3分钟和显影时间46秒），温度为36摄氏度。强调了将胶片传输时间误报为冲洗时间的普遍异常情况。提倡使用乳房X光片复制品来衡量胶片冲洗机变化的影响。对移动单元胶片冲洗机性能的仔细监测产生了与医院单元相当的稳定质量。概述了现场胶片冲洗的优点。建议在所有乳腺钼靶胶片库存中添加一个感光阶梯楔形块，作为评估图像质量的一种方法。
