PET (positron emission tomography) is used to preoperatively identify lymph node metastasis. However it is difficult to locate those lymph node metastasis during surgery. Intraoperative PET-laparoscope system consisting of an external fixed detector array and a movable detector which can be inserted into a patient’s stomach has been proposed to identify lymph node metastasis during gastric cancer surgery. This study presents the development of prototype detectors for PET-laparoscope system. A 7 × 7 array of 10 × 10 × 20 mm GAGG crystals coupled with SiPMs (Silicon photomultipliers) was used in the fixed detector. The movable detector used a single 10 × 10 × 5 mm GAGG crystal coupled with an SiPM for achieving the required spatial resolution around 10 mm. An optical tracking system was used to track the movable detector. SiPM outputs were read out by time-over-threshold (TOT) ASICs for converting the charge to digital pulses. An FPGA based DAQ system was used to determine the arrival time, pulse width carrying the energy information and channel number of each TOT output. During the first stage image reconstruction experiments the detector prototype could reconstruct images of a Na-22 point source with better than 10 mm spatial resolution in coronal and longitudinal directions although the resolution in sagittal (depth) direction was limited due to inadequate projections. The prototype detector performance with position tracking system will be presented at the conference.