Development of the X’tal Cube PET Detector With Segments of (0.77 mm)3

The depth-of-interaction detector which can identify gamma-ray detection position along the depth direction is essential for a PET scanner to reduce parallax error. The X'tal cube we have developed is composed of a scintillation crystal block segmented into cubes. Six arrays of multipixel photon counters (MPPCs) cover six surfaces of the crystal block. We developed the new X'tal cube consisting of 0.77 mm cubic segments. A (13.1 mm)
³
LYSO crystal block had 3-D segmentation in a 17 × 17 × 17 array fabricated by the laser engraving technique. 4 × 4 MPPC arrays with a size of (13 mm)
²
were used. Active area of each MPPC was (3.0 mm)
²
. To evaluate segment identification performance, we irradiated with gamma-rays from a
²²
Na source and obtained a 3-D position histogram made by the 3-D Anger-type calculation with all MPPC signals. The histogram showed 17 segments in a row can be identified clearly. Further, to measure its intrinsic spatial resolution with incident angles of 0° and 45°, gamma-rays in a fan-beam were irradiated and scanned onto the X'tal cube. Spatial resolutions of 0.74 ± 0.10 mm and 0.89 ± 0.10 mm were obtained by both scan experiments, respectively.