Development of novel PET detectors based on Geigermode Avalanche Photodiodes (G-APDs) for Molecular Imaging Applications

• Applicant: Professor Dr. Bernd Pichler
• Subject Area: Medical Physics, Biomedical Technology
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 101518311

This grant focuses on the development of advanced detectors for positron emission tomographs (PET) based on novel semiconductor photodiodes and fast readout electronics. Conventional PET detectors are based on an array of scintillation crystals - which convert the gamma rays into weak light flashes - and highly sensitive, low noise and fast photomultiplier tubes (PMT), which detect the scintillation light. These photodetectors are bulky and relatively cost-intensive and are not suited for multimodality medical imaging devices such as PET/MRI. As alternative to PMTs serve currently avalanche photodiodes (APDs), which are semiconductor-based and very compact but provide about 10³ lower electronic gain and worse timing resolution than PMTs. This impacts the PET image quality and quantification accuracy. Recently, high energy physics research groups focussed on the development of so-called Geiger-mode APDs (G-APDs) which provide all the advantages of standard APDs but have a gain comparable to that of PMTs, resolve single photoelectrons, operate at much lower voltage and have an exceptional timing resolution. Also, the future costs for these GAPDs detectors should be much lower than for APDs or PMTs because of the standard CMOS production technology. The work suggested in this proposal focus on the investigation of G-APDs for their suitability to be used in high resolution PET applications. We will develop a novel detector which works in high magnetic fields for combined PET/MRI and provides depth of interaction information for best achievable spatial resolution. Furthermore, fast readout electronics, specifically for G-APDs, will be developed.

• DFG Programme: Research Grants