First Results of the 4D-PET Brain System

Positron Emission Tomography (PET) imaging is the molecular technique of choice for studying many illnesses, including the ones related to the brain. Nevertheless, the use of PET scanners in neurology is limited by several factors, such as their limited availability for brain imaging due to the high oncology demand for PET and the low sensitivity and poor spatial resolution in the brain of the standard PET scanners. To expand the PET application in neurology, brain-specific systems with increased clinical and physical sensitivities and higher spatial resolution are required. The present work reports on the design and development process of a compact dedicated PET scanner suitable for human brain imaging. This paper includes the description and experimental validation of the detector components and their implementation in a full-size system called 4D-PET. The detector has been designed to simultaneously provide photon DOI and TOF information. It is based on the semi-monolithic LYSO modules optically coupled to SiPMs and connected to a multiplexing readout. The analog output signals are fed to the PETsys TOFPET2 ASIC circuits enabling scalability of the readout. The evaluation of the 4D-PET modules resulted in average detector resolutions of 2.111.0 mm, 3.411.8 mm, and 38619 ps for the y-(transaxial direction), DOI-, and CTR TOF, respectively. The preliminary 4D-PET imaging performance is reported through simulations and, for the first time, through the real reconstructed images (collected in the La Fe Hospital, Valencia).