Initial experience with a SiPM-based PET/CT scanner: influence of acquisition time on image quality

Abstract

BackgroundA newly introduced PET/CT scanner (Discovery Meaningful Insights—DMI, GE Healthcare) includes the silicon photomultiplier (SiPM) with time-of-flight (TOF) technology first used in the GE SIGNA PET/MRI. In this study, we investigated the impact of various acquisition times on image quality using this SiPM-based PET/CT.MethodsWe reviewed data from 58 participants with cancer who were scanned using the DMI PET/CT scanner. The administered dosages ranged 295.3–429.9 MBq (mean ± SD 356.3 ± 37.4) and imaging started at 71–142 min (mean ± SD 101.41 ± 17.52) after administration of the radiopharmaceutical. The patients’ BMI ranged 19.79–46.16 (mean ± SD 26.55 ± 5.53). We retrospectively reconstructed the raw TOF data at 30, 60, 90, and 120 s/bed and at the standard image acquisition time per clinical protocol (180 or 210 s/bed depending on BMI). Each reconstruction was reviewed blindly by two nuclear medicine physicians and scored 1–5 (1—poor, 5—excellent quality). The liver signal-to-noise ratio (SNR) was used as a quantitative measure of image quality.ResultsThe average scores ± SD of the readers were 2.61 ± 0.83, 3.70 ± 0.92, 4.36 ± 0.82, 4.82 ± 0.39, and 4.91 ± 0.91 for the 30, 60, 90, and 120 s/bed and at standard acquisition time, respectively. Inter-reader agreement on image quality assessment was good, with a weighted kappa of 0.80 (95% CI 0.72–0.81). In the evaluation of the effects of time per bed acquisition on semi-quantitative measurements, we found that the only time point significantly different from the standard time were 30 and 60 s (both with P < 0.001). The effects of dose and BMI were not statistically significant (P = 0.195 and 0.098, respectively). There was a significant positive effect of time on SNR (P < 0.001), as well as a significant negative effect of weight (P < 0.001).ConclusionsOur results suggest that despite significant delays from injection to imaging (due to comparison with standard PET/CT) compared to standard clinical operations and even in a population with average BMI > 25, images can be acquired as fast as 90 s/bed using the SiPM PET/CT and still result in very good image quality (average score > 4).

Evaluation of 18F-FDG PET/CT Images Acquired with a Reduced Scan Time Duration in Lymphoma Patients using the Digital Biograph Vision

“…As expected, a reduction of emission time led to an increase in image noise, which is in line with prior studies by van Sluis et al [11] and Sonni et al [23]. An in-depth overview of image noise across all employed reconstruction algorithms is provided in Fig.…”

Increased 18F-FDG signal recovery from small physiological structures in digital PET/CT and application to the pituitary gland

“…It is well known that, the 18 F-FDG uptake of small structures in PET is underestimated due to the important partial-volume-effects (PVE), affecting the emission signal recovery from these structures [6][7][8] . Spatial resolution, system sensitivity and image contrast in PET/CT have improved due to recently introduced solid-state digital PET/CT (dPET) [9][10][11] . A recent study has shown that Siemens Biograph Vision dPET has a 3.7 mm spatial resolution (vs 4.3 mm for Biograph mCT Flow cPET), and a 70.3% increased sensitivity compared to precedent Biograph mCT Flow cPET 11 .…”

The Impact of Patient’s Body Habitus on PET Image Quality in Digital and Analogic PET/CT

“…[ 18 F]FDG PET image quality decreases with weight and enlarging body habitus on digital and analogic PET/CT imposing further optimization and harmonization also in digital PET/CT. This is important for clinical routine, but also (multicentric) research and development of arti cial intelligence software.…”

“…However little has been described about the necessity and modalities of these compensatory techniques in dPET/CT. Positive in uence of acquisition time on PET IQ in dPET/CT has been reported in 58 oncologic patients [18] Our primary goal was characterizing on digital PET/CT the relation between patient's body mass index (BMI), weight, fatty mass (FM) and [ 18 F]FDG PET image quality, as an important rst step towards optimizing and harmonizing imaging protocols in digital PET/CT.…”