Advanced Photon Detection (Not only) for Clinical and Preclinical Imaging

por Christoph W. Lerche (Oncology Solutions, Philips Research)

jueves 19 jun. 2014 10:00 → 11:00 Europe/Madrid

Seminar Room 1.1.1 (IFIC)

A fully digital implementation of the Silicon Photomultiplier (SiPM) has been developed in order to overcome the deficiencies and limitations of the so far only analog SiPMs. The Digital Photon Counter (DPC) from Philips Digital Photon Counting is based on arrays of single photon avalanche diodes (SPADs) integrated in a standard CMOS process. Photons are detected directly by sensing the voltage at the SPAD anode using a dedicated cell electronics block next to each diode. This block also contains active quenching and recharge circuits as well as a one bit memory for the selective inhibit of detector cells. A balanced trigger network is used to propagate the trigger signal from all cells to the integrated time-to-digital converter. In consequence, photons are detected and counted as digital signals, thus making the sensor less susceptible to temperature variations and electronic noise. The integration with CMOS logic provides the added benefit of low power consumption and possible integration of data post-processing directly in the sensor. In this overview presentation, the sensor architecture and its characteristics are discussed.
As example of application, a fully digital, Magnetic Resonance Imaging (MRI)-hard and MRI-silent preclinical Positron Emission Tomography (PET) insert for the Clinical Achieva 3T MRI scanner from Philips Healthcare is presented and discussed. The usage of SiPM arrays for preclinical PET requires a revision of the algorithms for position and energy determination for high performance position sensitive scintillation detectors and a Maximum Likelihood based algorithm is presented. Both, Maximum Likelihood parameter extraction algorithms and Digital Photon Counter sensors are by no means limited in its application to clinical and preclinical imaging but may also enable alternative design and analysis concepts in particle physics.