Impact of the X’tal cube detector with isotropic resolution on PET image resolution

Objectives The X’tal cube is our new PET detector, which is being developed to achieve isotropic 3D positioning detectability. The X’tal cube is based on a segmented 3D crystal block for which all surfaces are covered with photo-detectors. We have shown that the X’tal cube can achieve isotropic intrinsic resolution with the Anger-type calculation even at the block edges. In this work, we developed a new one pair prototype system to simulate a ring-type scanner, and evaluated imaging performance of the X’tal cube detector.

Methods The developed system consisted of two X’tal cube detectors, two rotating stages, and a 192-channel data acquisition system. The X’tal cube consisted of the LYSO cubic crystal block of (18 mm)³ in which the 3D grids of 2 mm pitch were fabricated by the internal laser processing. 4 x 4 arrays of multi pixel photon counters (MPPCs) were optically coupled to each surface of the crystal block. The detector positions were automatically controlled to simulate a ring-type PET of 14.6 cm in diameter. Data were collected for assumed all detector positions and then a sinogram was obtained. The data were reconstructed using the filtered backprojection.

Results We successfully obtained uniform spatial resolution less than 2 mm over the FOV.

Conclusions We developed a one pair prototype system for the X’tal cube detector, and we confirmed its potential for high-resolution imaging.

Research Support This research was supported by a fund from Japan Science and Technology Agency (JST), Development of Systems and Technology for Advanced Measurement and Analysis