Four-layer DOI detector with a relative offset in animal PET system

In order to build an animal PET system with high sensitivity and resolution, we propose a four-layer PET system which provides the DOI (depth of interaction) information. Each crystal layer has a relative offset of half the crystal pitch with each other and uses an identical type of crystals simplifying readout electronics. The proposed system PET system consists of four LYSO (Lu
₁₈
Y
_0.2
SiO
₅
:Ce) or L
_0.9
GSO (Lu
_1.8
Gd
_0.2
Si
_0.4
:Ce) crystal layers with a crystal dimension of 1.5times1.5times5.0 mm
³
. The animal PET system has a diameter of 84 mm with one Hamamatsu H9500 flat panel PMT ring, and can be upgraded to two PMT ring configuration. An estimated efficiency using GATE simulation is ~15% at the center of one detector ring system. We present flood images obtained with a
²²
Na radiation source to verify the concepts of the proposed system, and obtained promising results.