Kimme-Smith C, Rothschild P A, Bassett L W, Gold R H, Moler C
Department of Radiological Sciences, Iris Cantor Mammography Screening Center, UCLA School of Medicine 90024-1721.
AJR Am J Roentgenol. 1989 Jan;152(1):35-40. doi: 10.2214/ajr.152.1.35.
Six different combinations of film-processor temperature (33.3 degrees C, 35 degrees C), development time (22 sec, 44 sec), and chemistry (Du Pont medium contrast developer [MCD] and Kodak rapid process [RP] developer) were each evaluated by separate analyses with Hurter and Driffield curves, test images of plastic step wedges, noise variance analysis, and phantom images; each combination also was evaluated clinically. Du Pont MCD chemistry produced greater contrast than did Kodak RP chemistry. A change in temperature from 33.3 degrees C (92 degrees F) to 35 degrees C (95 degrees F) had the least effect on dose and image contrast. Temperatures of 36.7 degrees C (98 degrees F) and 38.3 degrees C (101 degrees F) also were tested with extended processing. The speed increased for 36.7 degrees C but decreased at 38.3 degrees C. Base plus fog increased, but contrast decreased for these higher temperatures. Increasing development time had the greatest effect on decreasing the dose required for equivalent film darkening when imaging BR12 breast equivalent test objects; ion chamber measurements showed a 32% reduction in dose when the development time was increased from 22 to 44 sec. Although noise variance doubled in images processed with the extended development time, diagnostic capability was not compromised. Extending the processing time for mammographic films was an effective method of dose reduction, whereas varying the processing temperature and chemicals had less effect on contrast and dose.
对胶片冲洗机温度（33.3摄氏度、35摄氏度）、显影时间（22秒、44秒）和化学药剂（杜邦中对比度显影剂[MCD]和柯达快速冲洗[RP]显影剂）的六种不同组合，分别通过赫特和德里菲尔德曲线分析、塑料阶梯楔测试图像、噪声方差分析和体模图像进行评估；每种组合也进行了临床评估。杜邦MCD化学药剂产生的对比度比柯达RP化学药剂更高。温度从33.3摄氏度（92华氏度）变为35摄氏度（95华氏度）对剂量和图像对比度的影响最小。还对36.7摄氏度（98华氏度）和38.3摄氏度（101华氏度）的温度进行了延长冲洗测试。36.7摄氏度时速度增加，但38.3摄氏度时速度降低。对于这些较高温度，片基加灰雾增加，但对比度降低。在对BR12乳腺等效测试物体成像时，增加显影时间对降低等效胶片黑化所需剂量的影响最大；电离室测量显示，当显影时间从22秒增加到44秒时，剂量降低了32%。尽管延长显影时间处理的图像中噪声方差增加了一倍，但诊断能力并未受到影响。延长乳腺摄影胶片的冲洗时间是一种有效的剂量降低方法，而改变冲洗温度和化学药剂对对比度和剂量的影响较小。
