Barreloid Deformation Correction in Planar Imaging

Unbalanced amount of the accumulated charge on the anodic grid of a Photomultiplier Tube combined with Center of Gravity position reconstruction algorithms produces systematically shifts towards the center of the image, reducing the effective Field of View and causing deformation effects at the edges of the image. The main purpose of this study is to detect the origin of this kind of image deformation, mainly known as barreloid distortion, and in addition to propose appropriate algorithmic approaches for the correction of these effects on planar imaging. Various analyses with simulated and real data are presented and the success of the method is discussed with different phantom geometries measured with a small field γ-Camera system.