Performance comparison of two commercial small animal PET scanners: ClearPETT and rPET-1T

Abstract

Abstract-It is usually difficult to compare different designs of Positron Emission Tomography (PET) small-animal scanners because of the disparity of measurements protocols. In this work we compare two commercial PET scanners installed at ClEMAT (Madrid, Spain): the ClearPET and the rPET-I, using an assessment procedure that fulfilled the recommendations of the new NEMA NU 4-2008 standard to evaluate small animal PET systems, including spatial resolution, sensitivity, scatter fraction and count losses studies. The scanners evaluated have significant geometrical differences, like the axial field of view (110 mm on ClearPET versus 45.6 mm on rPET-l), the configuration of the detectors (one pair of planar blocks on rPET-I, versus whole ring detectors on ClearPET) and the use of an axial shift between ClearPET module detectors. Our experiments showed a FWHM (FOV center, averaged over the three axes) of 1.98 mm for the rPET-1 and 2.15 rom for the ClearPET, with a small variation across the transverse axis on both scanners «1 rom). The absolute sensitivity was 1.0% per detector pair for rPET-I and 4.70/0 for ClearPET. Regarding count losses studies, the obtained peak NEC rate is 73.4 kcps at 0.51 MBq/ml for the ClearPET and 29.2 kcps at 1.35 MBq/ml for the rPET-1, considering a NEMA mouse-like phantom.

Design and performance evaluation of a coplanar multimodality scanner for rodent imaging

“…The PET component of this scanner is based on a partial ring PET tomograph called rPET, previously developed at our institution (Vaquero et al 2005). This system consisted of four detector heads arranged as two orthogonal pairs of diagonally opposed detectors, providing a field of view (FOV) of approximately 45 × 45 × 45 mm 3 and an absolute sensitivity of 1% per detector pair (Cañadas et al 2008). The development of the VrPET/CT was motivated by the idea of integrating the rPET system with a micro-CT, simultaneously improving some functional and technological features.…”

Validation of a small-animal PET simulation using GAMOS: a GEANT4-based framework

“…Resolution at the same transaxial points was also evaluated at 1 4 axial FOV. Although acquisition at 0 mm is not included in the NEMA document, results at this location have been presented in previous characterizations of the system (Canadas et al 2008, Roldan et al 2007. More than 10 5 prompt counts were acquired per measurement, and analytic image reconstruction algorithms with no-smoothing filters were applied: a 3D filtered back projection algorithm (the FBP3DRP algorithm from the STIR package) with an image pixel size of 0.38 mm × 0.38 mm and a slice thickness of 1.15 mm.…”

“…In both cases it is not possible to resolve the smaller rods. Nevertheless, it is important to remark that better images can be obtained in the ClearPET with longer acquisitions (Canadas et al 2008); for these studies we were only interested on comparing the acquired image against the simulation under the same number of coincidences. A 2 min acquisition was carried out on the system to collect 3 million coincidences from the mini-Derenzo phantom.…”

Accurate Monte Carlo modeling and performance assessment of the X‐PET™ subsystem of the FLEX Triumph™ preclinical PET/CT scanner

“…9 Since then, some publications reported on the measurement of performance parameters of various preclinical PET systems using this standard. 4,[10][11][12][13][14][15][16][17] Monte Carlo ͑MC͒ techniques are widely used for the simulation of medical imaging systems including small animal PET scanners. 18 Up to now, Monte Carlo-based performance assessment of the X-PET ™ relied on a rough and simple model of the detector geometry owing to its complexity, which might lead to errors in the obtained results.…”