Ludlow J B, Platin E
Diagnostic Sciences Department, University of North Carolina School of Dentistry, Chapel Hill, USA.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1995 Jan;79(1):105-13. doi: 10.1016/s1079-2104(05)80084-8.
This study compared film speed, contrast, exposure latitude, and resolution of Ultra-speed, Ektaspeed, and Ektaspeed Plus films (Eastman Kodak Co., Rochester, N.Y.). Densitometric curves were generated for each film type under processing conditions of fresh and used chemistry to observe their effect on factors associated with diagnostic quality. Ektaspeed Plus film displayed the least variability due to processing condition of any film; it also demonstrated the fastest speed and was twice as fast as Ultra-speed film. Ektaspeed exhibited the greatest relative exposure latitude followed by Ektaspeed Plus and Ultra-speed. Average gradient over a clinically useful range of densities was greatest for Ultra-speed in fresh processing solutions, but greatest for Ektaspeed Plus in used processing solutions. All film types were able to resolve more than 16.6 line pairs per millimeter regardless of processing conditions. The results of this study suggest that dental practitioners who have refrained from using E-speed film because of the sensitivity of this film to variations in processing may now consider providing this dose-reducing technology for their patients with the expectation of obtaining consistent image quality.
本研究比较了超高速胶片、柯达超感速胶片和柯达超感速增强型胶片(伊士曼柯达公司,纽约州罗切斯特)的胶片速度、对比度、曝光宽容度和分辨率。在新鲜显影液和使用过的显影液的冲洗条件下,为每种胶片类型生成密度曲线,以观察其对与诊断质量相关因素的影响。在所有胶片中,柯达超感速增强型胶片因冲洗条件导致的变化最小;它还显示出最快的速度,是超高速胶片速度的两倍。柯达超感速胶片的相对曝光宽容度最大,其次是柯达超感速增强型胶片和超高速胶片。在新鲜冲洗液中,超高速胶片在临床上有用的密度范围内的平均梯度最大,但在使用过的冲洗液中,柯达超感速增强型胶片的平均梯度最大。无论冲洗条件如何,所有胶片类型都能够分辨每毫米超过16.6线对。本研究结果表明,那些因E速胶片对冲洗变化敏感而一直未使用该胶片的牙科医生,现在可能会考虑为患者提供这种减少剂量的技术,以期获得一致的图像质量。