A Monte-Carlo simulation study for design of brain dedicated TOF-PET

Brain positron emission tomography (PET) has several advantages, including improved sensitivity and spatial resolution compared to whole-body PET, which provides a more accurate diagnosis and observation of metabolic activity in the brain. However, the small diameter and design parameter result in a high parallax error and a random count rate, leading to a deteriorated imaging performance. We designed and evaluated brain PET with various design parameters and applied time-of-flight (TOF) technology to overcome the above problems. The aim of the study was to design an optimal structure of the brain dedicated TOF-PET that provides excellent image quality. This study investigated effects of ring diameter, crystal length, and TOF capability on the performance of brain TOF-PET using a Monte-Carlo simulation. Two brain PET were designed and evaluated, consisting of a commercially available brain PET ring diameter (357 mm) and a smaller ring diameter (257 mm) to verify the effect of ring diameter on the performance of the brain PET. Three brain TOF-PET with different crystal thicknesses (10 mm, 15 mm, and 20 mm) and TOF capacities (180 ps, 220 ps, and 260 ps) were assessed and their performances were compared. An optimization study was also performed to design the optimal structure based on the two simulation results. This study determined the optimal structure of brain-dedicated TOF-PET based on trade-offs and performance differences depending on the parameters of brain PET. As a result, we propose a brain-dedicated TOF-PET with a 15 mm crystal length and 257 mm diameter as the optimal structure. The results of this paper could be used to design PET systems for the brain and other specific organs.