In-Vivo Dosimetry for Photon Radiotherapy Based on Pair Production

Research output: Contribution to journalResearch articleContributedpeer-review



Experience during percutaneous ion beam therapy at Gesellschaft für Schwerionenforschung showed that the treatment can be improved by in-vivo dose monitoring that is independent of the irradiation device and based on positron emission tomography. It has been studied whether a similar technique can be implemented for high energy photon therapy. Simulation shows that the dose is closely related to the distribution of the annihilation points of positrons emerging from pair production. Design parameters of a detector system have been assessed which is capable of registering annihilation radiation during treatment. A test system has been assembled which can be operated with various scintillator crystals and avalanche photodiodes. A custom digital signal processing system has been implemented. Phantom experiments at a clinical linear accelerator disclosed a severe background that does not solely stem from scattered primary photons but from radiation directly emitted from the treatment head. It was not possible to shield the detectors sufficiently and thus there was no success in identifying annihilation radiation.


Original languageEnglish
Article number5485093
Pages (from-to)1125-1131
Number of pages7
JournalIEEE transactions on nuclear science
Issue number3
Publication statusPublished - 1 Jun 2010

External IDs

Scopus 77953716907
ORCID /0000-0001-9023-3606/work/142252749



  • Medical treatment, Radiation detectors, Ion beams, Monitoring, Positron emission tomography, Production, System testing, Assembly systems, Photonic crystals, Avalanche photodiodes