Resolution of a Gamma camera: Analytical vs Experimental methods

Davide Poggiali, University of Padova

It is well known that resolution varies as a function of distance, scatter and the gamma camera's characteristics. Manufacturers frequently provide only a few pre-calculated resolution values however that are typically not obtained in situations resembling a clinical setting. From a diagnostic point of view, it is useful to know which is the expected resolution of a gamma camera at a given distance from the collimator surface for a particular setting in order to decide whether it is worth scanning patients with small lesion. When dealing with absolute quantification it is also mandatory to know precisely the expected resolution and its uncertainty in order to make appropriate corrections. Three mathematical methods for calculating FWHM from a planar scintigraphy were tested and compared. An open package Resolution Calculator was created to obtain the theoretical resolution of a gamma camera at different distances (analytical resolution) and compare it with real data obtained from the acquisition of a line source located at different distances from the collimator (experimental resolution).