| Tumor motion limits the accuracy of radiation therapy. Positron emission tracking (PeTrack) is a technique that can track tumors through detecting annihilation gammas from implanted positron emission markers. This thesis focuses on detector development for PeTrack. Due to the intense scattered x rays from a Linac, scintillator (BGO) afterglow and detector gating, i.e. turning off the detector during the intense x-ray pulse, need to be addressed. The evaluation of BGO showed very low afterglow. A gating circuit was designed, optimized and tested. Energy resolution of the detector is better than 25% (FWHM) with optimal gating parameters. A data acquisition system for PeTrack was set up and calibrated successfully. The first PeTrack prototype was developed and evaluated. The prototype was able to localize two positron emitting markers with an average precision of 0.16-0.21 mm, and an average accuracy of 0.6 mm on distance between the two markers. |
