Performance evaluation of the Ingenuity TF PET/CT scanner with a focus on high count-rate conditions

Abstract

This study evaluated the positron emission tomography (PET) imaging performance of the Ingenuity TF 128 PET/computed tomography (CT) scanner which has a PET component that was designed to support a wider radioactivity range than is possible with those of Gemini TF PET/CT and Ingenuity TF PET/MR. Spatial resolution, sensitivity, count rate characteristics and image quality were evaluated according to the NEMA NU 2–2007 standard and ACR phantom accreditation procedures; these were supplemented by additional measurements intended to characterize the system under conditions that would be encountered during quantitative cardiac imaging with 82Rb. Image quality was evaluated using a hot spheres phantom, and various contrast recovery and noise measurements were made from replicated images. Timing and energy resolution, dead time, and the linearity of the image activity concentration, were all measured over a wide range of count rates. Spatial resolution (4.8– 5.1 mm FWHM), sensitivity (7.3 cps kBq−1), peak noise-equivalent count rate (124 kcps), and peak trues rate (365 kcps)were similar to those of the Gemini TF PET/CT. Contrast recovery was higher with a 2 mm, body-detail reconstruction than with a 4 mm, body reconstruction, although the precision was reduced. The noise equivalent count rate peak was broad (within 10% of peak from 241–609 MBq). The activity measured in phantom images was within 10% of the true activity for count rates up to those observed in 82Rb cardiac PET studies.

Improving the Detection of Small Lesions Using a State-of-the-Art Time-of-Flight PET/CT System and Small-Voxel Reconstructions

“…The CRC measurements in our phantom study for both standard-and small-voxel reconstructions are consistent with the results of Kolthammer et al (16). Furthermore, the improvement of CRCs for small-voxel reconstructions implies an improved image resolution, which has a direct impact on the interpretation of clinical SUV measurements of small lesions.…”

“…In current practice, the image voxel size for whole-body 18 F-FDG PET scans is typically around 4 · 4 · 4 mm (7,16). Conti (7) suggested that in combination with new high sensitive TOF PET/CT cameras, the use of reconstructions with smaller voxels might further improve the detection of small lesions.…”

Advances in time-of-flight PET

“…Currently all three major PET vendors have at least one version of a TOF PET/CT system available, with Siemens using LSO, while Philips and GE use LYSO or another lutetium-based scintillator, respectively. The timing resolution for all of these systems (Philips Ingenuity, Siemens mCT, and GE Discovery 690) is in the range of 500–550 ps using 20–25 mm long crystals [26–28]. In addition to these three major PET vendors, Toshiba has recently introduced the Celesteion PET/CT system, which achieves a system timing resolution of ~400 ps while also using LYSO crystals [29].…”

Noninvasive Quantification of Myocardial 11C-Meta-Hydroxyephedrine Kinetics

“…Images were reconstructed into 36 frames, with all appropriate corrections applied, using either the standard 3-dimensional row-action maximum-likelihood algorithm (3DR) reconstruction protocol as implemented on the Gemini scanner or the latest version of the time-offlight (TF) reconstruction protocol, which comes with Monte Carlo (19)-based scatter correction and will be implemented in the current generation of Philips scanners (Ingenuity TF) (20).…”