An extended bore length solid-state digital-BGO PET/CT system: design, preliminary experience, and performance characteristics.

PURPOSE: A solid-state PET/CT system uses bismuth germanium oxide (BGO) scintillating crystals coupled to silicon photomultipliers over an extended 32 cm axial field-of-view (FOV) to provide high spatial resolution and very high sensitivity. Performance characteristics were determined for this digital-BGO system, including NEMA and EARL standards. METHODS: Spatial resolution, scatter fraction (SF), noise equivalent count rate (NECR), sensitivity, count rate accuracy, and image quality (IQ) were evaluated for the digital-BGO system as per NEMA NU 2-2018, at 2 sites of first clinical install. System energy resolution was measured. Bayesian penalized-likelihood reconstruction (BPL) was used for IQ. EARL Standards 2 studies were reconstructed by BPL combined with a contrast-enhancing deep learning algorithm. An Esser PET phantom was evaluated. Three patient examples were obtained with low-dose radiotracer activity: 2 MBq/kg of [18F]FDG ([18F]-2-fluoro-2-deoxy-D-glucose), 2.3 MBq/kg [68Ga]Ga-DOTA-TATE ([dodecane tetra-acetic acid,Tyr3]-octreotate), and 14.5 MBq/kg [82Rb]RbCl ([82Rb]-rubidium-chloride). Total scan times were ≤ 8 min. RESULTS: NEMA sensitivity was 47.6 cps/kBq at the axial center. Spatial resolution at 1 cm from the center axis was ≤4.5 mm (filtered back projection) and ≤3.8 mm (ordered subset expectation maximization). SF was 35.6%, count rate accuracy was 2.16%, and peak NECR was 485.2 kcps at 16.9 kBq/mL. Contrast for IQ was 61.1 to 90.7% (smallest to largest sphere) with background variations from 7.6 to 2.1%, and a "lung" error of 4.7%. The average detector energy resolution was 9.67%. Image quality for patient scans was good. EARL Standards 2 criteria were robustly met and Esser phantom features ≥4.8 mm were resolved at 2 min per bed position. CONCLUSION: A solid-state 32 cm axial FOV digital-BGO PET/CT system provides good spatial and energy resolution, high count rates, and superior NEMA sensitivity in its class, enabling fast clinical acquisitions with low-dose radiotracer activity.

[18F-FDG-PET/CT AS A TOOL FOR DIAGNOSIS AND FOLLOW-UP OF INFLAMMATORY DISEASES OF LARGE BLOOD VESSELS].

INTRODUCTION: Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) / Computed Tomography (FDG-PET/CT) is a well-established functional-anatomical imaging technique mostly used in oncology. In addition, it was found to have an important role in the diagnosis and follow-up of large vessel vasculitis mainly when combined with computed tomography angiography. Large vessel vasculitis is a disease mainly affecting large blood vessels and has two major groups: Takayasu arteritis (TA) and Giant cell arteritis (GCA). GCA is usually accompanied by polymyalgia rheumatica (PMR).

[IS MYOCARDIAL PERFUSION IMAGING INTERPRETATION HARDER WITH X-RAY BEAM HARDENING ARTIFACT?]

INTRODUCTION: Myocardial perfusion imaging (MPI) is a well-established imaging modality for the diagnosis of coronary artery disease and for prognostication. In recent years, the management of heart failure has developed tremendously including implantation of defibrillators for prevention of malignant tachyarrhythmias and resynchronizing therapy for the improvement of clinical symptoms and left ventricular function. Cardiac magnetic resonance and computed tomography are imaging modalities that are negatively affected by the presence of metallic devices. MPI is a hybrid study combining computed tomography for attenuation correction and nuclear imaging. This case shows that a metal device has no effect on the interpretation of MPI.