The Effects of Collimator Malpositioning in Seven Pinhole Tomography

Abstract

We tested the effect of seven pinhole collimator positioning on circumferential count profiles during thallium-201 myocardial imaging by imaging a left ventricular phantom at various angles. The seven pinhole raw data images and profiles were identifiable as malpositioned when the collimator was malpositioned by 10° or more. The phantom’s “cold” spot was shown to propagate into adjacent planes and also into other regions of the heart as a function of collimator positioning. We then developed a method for systematically positioning the collimator correctly, which should aid in preventing similar artifacts in clinical studies.