Comparative study of physiological FDG uptake in small structures between silicon photomultiplier-based PET and conventional PET.

Objective: Silicon photomultiplier-based positron emission tomography/computed tomography (SiPM-PET/CT) has the superior spatial resolution to conventional PET/CT (cPET/CT). This head-to-head comparison study compared the images of physiological F-fluorodeoxyglucose (FDG) accumulation in small-volume structures between SiPM-PET/CT and cPET/CT in patients scanned with both modalities, and we investigated whether the thresholds that are reported to be useful for differentiating physiological accumulations from malignant lesions can also be applied to SiPM-PET/CT.

Methods: We enrolled 21 consecutive patients with head and neck malignancies who underwent whole-body FDG-PET/CT for initial staging or a follow-up evaluation (October 2020 to March 2022).

Halo artifacts of indwelling urinary catheter by inaccurate scatter correction in F-FDG PET/CT imaging: incidence, mechanism, and solutions.

Background: Halo artifacts from urinary catheters can occur due to inaccurate scatter correction, and the artifacts affect the tumor visibility in F-FDG PET/CT images. We investigated the incidence rate and the mechanisms of halo-artifact generation and explored several scatter correction techniques to prevent artifacts.

Methods: We conducted patient and phantom studies.

PET/CT scanning with 3D acquisition is feasible for quantifying myocardial blood flow when diagnosing coronary artery disease.

Background: The quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR) are useful approaches for evaluating the functional severity of coronary artery disease (CAD). O-water positron emission tomography (PET) is considered the gold standard method for MBF quantification. However, MBF measurements in O-water PET with three-dimensional (3D) data acquisition, attenuation correction using computed tomography (CT), and time of flight have not been investigated in detail or validated.

An improved MR sequence for attenuation correction in PET/MR hybrid imaging.

The aim of this study was to investigate the effects of MR parameters on tissue segmentation and determine the optimal MR sequence for attenuation correction in PET/MR hybrid imaging. Eight healthy volunteers were examined using a PET/MR hybrid scanner with six three-dimensional turbo-field-echo sequences for attenuation correction by modifying the echo time, k-space trajectory in the phase-encoding direction, and image contrast. MR images for attenuation correction were obtained from six MR sequences in each session; each volunteer underwent four sessions.