Basic evaluation of a C-shaped breast PET scanner

Abstract

For diagnosis of very small lesions of breast cancer on very early stage, a dedicated breast positron emission tomography (PET) scanner consisting of four-layer depth of interaction (DOI) detectors is now under development. We are aiming for the spatial resolution of less than 1 mm across a large effective field of view (FOV), and acquisition time of less than 5 minutes for each breast and 10 minutes in total. The C shape of this scanner allows it to be positioned closely around the breast, effectively increasing both resolution and sensitivity. The C-shaped design of the scanner accommodates a variety of patient physiques, ensuring inclusion of the entire breast into the effective FOV. The detector consists of four-layer of a 32 × 32 Lu 1.8 Gd 0.2 SiO 5 (LGSO) crystal array, a light guide and a 64ch position-sensitive photomultiplier tube (H8500). The size of crystal element is 1.44 mm × 1.44 mm × 4.5 mm. The detector ring consists of 24 detector modules arranged in a 2-ring configuration with a diameter of 228 mm and an axial extent of 105 mm. We developed a prototype equipment of C-shaped breast PET scanner, and also developed a full-ring PET scanner for comparison. We report basic evaluation of each prototype, such as, sensitivity, count rate, resolution, and image quality of phantoms.