Accorsi Roberto, Metzler Scott D
Department of Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
IEEE Trans Med Imaging. 2005 Dec;24(12):1637-46. doi: 10.1109/TMI.2005.857229.
The effects of penetration are included in the formulas for the prediction of the resolution of pinhole collimators through the use of effective diameters. Expressions of the resolution-effective diameter for pinholes with a double-knife-edge (DKE) profile are available in the literature. In this paper the expressions applicable to asymmetric-knife-edge (AKE) profiles, which include the important case of the single-knife-edge (SKE), are presented. Results indicate that the simplest methods that are still accurate in the calculation of DKE effective diameters do not produce in general formulas with similar accuracy for AKE profiles, due to increased susceptibility to penetration. Especially at high energy (365 keV), for the SKE case more advanced formulas are necessary and were, therefore, derived.
穿透效应通过有效直径纳入针孔准直器分辨率预测公式中。文献中可获取双刃边（DKE）轮廓针孔的分辨率-有效直径表达式。本文给出了适用于不对称刃边（AKE）轮廓的表达式，其中包括单刃边（SKE）这一重要情况。结果表明，在计算DKE有效直径时仍准确的最简单方法，通常无法产生对AKE轮廓具有类似精度的通用公式，因为对穿透更敏感。特别是在高能（365 keV）时，对于SKE情况，需要更先进的公式，因此已推导得出。
