Performance comparison of two dual‐head coincidence cameras of the first and latest generation

Abstract

This study compares the performance and image quality of two gamma camera based PET systems of the first and latest generation. We investigated two dual head coincidence gamma cameras (PRISM 2000XP and AXIS, manufactured in 1997 and 2001 by Picker/Philips) predominantly in accordance with the NEMA NU2-1994 and NU2-2001 protocols. All performance parameters except for spatial resolution and image quality were determined after measuring a standard cylinder over several half-life periods. Scatter and random fractions were evaluated with the sinogram technique. In order to determine spatial resolution and image quality we used phantoms as described in the NEMA NU2-2001 protocol. The efficiency of the new system was found to be increased. True count rate at activity levels used in clinical conditions is improved and scatter fraction is decreased substantially. Accordingly, improved spatial resolution and image quality were observed with the new system. Altogether, the AXIS represents a further approach to the performance of dedicated positron emission tomographs.

A Monte Carlo simulation of coincidence detection and imaging of gamma-ray cascades with a scintillation camera

“…One approach that was pursued in the past involved modifications of the gamma camera energy range combined with coincidence electronics, serving as an alternative to dedicated PET systems (Miyaoka et al 1995, Patton and Turkington 1999, Sossi et al 2003. While the performance of these dual-head coincidence cameras were lower compared to dedicated PET systems, they served as a cost-effective approach to both nuclear medicine and PET imaging (Nellemann et al 1995, Kunze et al 2000, Schelper et al 2006. These scanners have since fallen out of favor, and thus the modern generation of gamma cameras possess neither the coincidence circuitry nor the timing electronics required for coincidence imaging.…”