Kubota H, Ozaki Y, Matsumoto M, Kanamori H
Information Processing Center, Shiga University, Japan.
Med Phys. 1993 Jul-Aug;20(4):1023-8. doi: 10.1118/1.596999.
This paper proposes a radiographic sensitivity attenuation curve for screen-films systems. This curve expresses the relative inverse value of mAs value needed to give the same photographic density. This curve decreases more slowly with increasing object thickness than the exposure attenuation curve generally used hitherto. By using the radiographic sensitivity attenuation curve and the exposure attenuation curve, the voltage-ripple dependence of mAs values and patient dose for the same photographic density was obtained. As predicted theoretically in a previous paper [Med. Phys. 18, 921 (1991)], it was verified quantitatively the reverse order that larger ripple values resulted in lower patient dose and lower mAs value for the unsaturating current mode at large ripple. This reverse order clearly appeared in two-pulse units. These phenomena were experimentally verified. As a result it was found that in radiographing with a two-pulse unit, larger mA value results in lower patient dose.
本文提出了一种针对增感屏 - 胶片系统的射线照相灵敏度衰减曲线。该曲线表示产生相同照相密度所需的mAs值的相对倒数。与迄今普遍使用的曝光衰减曲线相比，随着物体厚度增加，此曲线下降得更缓慢。通过使用射线照相灵敏度衰减曲线和曝光衰减曲线，得出了相同照相密度下mAs值和患者剂量对电压纹波的依赖性。正如在先前一篇论文[《医学物理》18, 921 (1991)]中理论预测的那样，定量验证了在大纹波下不饱和电流模式中更大纹波值导致更低患者剂量和更低mAs值的相反顺序。这种相反顺序在双脉冲单元中清晰出现。这些现象得到了实验验证。结果发现，在用双脉冲单元进行射线照相时，更大的mA值会导致更低的患者剂量。
