Development of beta imaging probe in endoscopy

Positron imaging for cancers in endoscope inspection is promising to detect overlooked small or unclear carcinomas since it enables double inspection of structure by optical image and function by radio image. There have been researches about positron probes with scintillation detector. We have investigated, designed and fabricated Si based positron detectors, which has an advantage in its high energy resolution and sensitivity. Simulation with EGS is executed to determine the optimal detector, detector thickness and available condition in human body. The optimal thickness of Si detectors is 1.0 mm and the thickness of obstruction should be less than 0.6 mm. We also fabricated a Si detector with diameter of 2.2 mm and thickness of 1 mm with a cable. Fabricated Si detectors is confirmed to successfully detect the emitted positrons. We are now in the stage to implement Si detector inside the endoscope.