Abstract ID: 16889 Title: Feasibility study of using Multi-Pixel Photon Counter (MPPC) as energy resolved photon counting detector
Purpose: Energy resolved x-ray photon counting detector is an enable technique for energy
resolved CT system. A popular choice is Cd-Te or CZT direct conversion x-ray detector. But
this kind of detector suffers low counting rate and therefore is unsuitable in clinical imaging.
Multi-Pixel Photon Counter (MPPC) is a new device that potentially can achieve much higher
photon counting rate. In this study, we investigated the feasibility of using MPPC as x-ray
photon counting detector.
Method and Materials: We designed and assembled a MPPC photon counting module with a
Hamamatsu MPPC coupled with a LYSO scintillator. The photon pulses were recorded by a
GHz digital oscilloscope and stored in a computer. We developed a signal pulse model which
can be used to determine the instance and height of each pulse. To further increase the counting
rate, a signal processing algorithm was used to discern multiple partially overlapped pulses.
Results: Based on the position and height of the MPPC pulses, the time and energy of an x-ray
photon event can obtain by fitting the model with measured signal. The developed signal
processing algorithm can further differentiate x-ray photons that are piled up together. A higher
than 20 Mcounts/s can easily achieve by MPPC counters.
Conclusion: MPPC photon counter coupled with LYSO scintillator can achieve a much faster
photon counting rate than Cd-Te or CZT detector. It is a promising x-ray photon counter that
potentially can reduce energy resolved CT scanning time to a clinically acceptable range.