Title :
Resolution-effective diameters for asymmetric-knife-edge pinhole collimators
Author :
Accorsi, Roberto ; Metzler, Scott D.
Author_Institution :
Dept. of Radiol., Children´´s Hosp. of Philadelphia, PA, USA
Abstract :
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.
Keywords :
collimators; image resolution; single photon emission computed tomography; 365 keV; asymmetric-knife-edge pinhole collimators; asymmetric-knife-edge profile; double-knife-edge profile; image resolution; resolution-effective diameters; single-knife-edge profile; Animal structures; Apertures; Geometry; High-resolution imaging; Humans; Image resolution; Optical collimators; Radiology; Single photon emission computed tomography; Slabs; Collimator; SPECT; image resolution; photon penetration; pinhole; single photon emission computed tomography; small-animal imaging; Animals; Computer Simulation; Equipment Failure Analysis; Image Enhancement; Image Interpretation, Computer-Assisted; Models, Biological; Reproducibility of Results; Sensitivity and Specificity; Tomography, Emission-Computed, Single-Photon;
Journal_Title :
Medical Imaging, IEEE Transactions on
DOI :
10.1109/TMI.2005.857229
