Haus A G, Dickerson R E
Health Sciences Division, Eastman Kodak Company, Rochester, New York 14650.
Med Phys. 1990 Jul-Aug;17(4):691-5. doi: 10.1118/1.596468.
Over the past ten years the evolution of medical x-ray films has been toward films with reduced intensifying-screen light crossover in order to reduce blur and obtain higher spatial resolution. For films with very low crossover, misleading and incorrect sensitometric data may be obtained for film contrast evaluation and processor control if a simulated light sensitometer with a single-sided, light-exposing device is used. Screen light exposures were made using an inverse square, intensity-scale sensitometer. Simulated light exposures were made using a widely used single-sided, simulated-light sensitometer commonly used for film processor quality control, and a new simulated-light sensitometer capable of producing either single- or double-sided sensitometric exposures. The films used included one single-emulsion film and three double-emulsion medical x-ray films with light-crossover values ranging from approximately 3% to 30%. Sensitometric data showed a significant distortion (bump) in the characteristic curve for the 3% light-crossover film exposed with the single-sided, simulated-light sensitometer.
在过去十年中，医用X射线胶片的发展趋势是采用减少增感屏光交叉的胶片，以减少模糊并获得更高的空间分辨率。对于交叉率极低的胶片，如果使用具有单面曝光装置的模拟光密度计来评估胶片对比度和控制冲洗机，可能会获得误导性和不正确的感光测定数据。使用反平方强度刻度密度计进行屏光曝光。使用一种广泛用于胶片冲洗机质量控制的常用单面模拟光密度计，以及一种能够进行单面或双面感光测定曝光的新型模拟光密度计进行模拟光曝光。所使用的胶片包括一张单乳剂胶片和三张双乳剂医用X射线胶片，其光交叉值范围约为3%至30%。感光测定数据显示，用单面模拟光密度计曝光的3%光交叉胶片的特性曲线出现了明显的失真（凸起）。
