Project Acronym: UTOFPET

Full title: Ultra-Time-Of-Flight Positron Emission Tomography with multi-channel digital Silicon photomultipliers and photonic crystals

Project duration: 45 months
Coordinator: Nicola Belcari (Department of Physics “E. Fermi”, University of Pisa)

Project website address: www.utofpet.com

Executive summary

Multi-parametric molecular imaging (MMI) is an imaging modality largely based on clinical PET that allowed many of the recent discoveries on new molecular probes and the associated models. MMI is a fundamental pillar of the so-called personalised medicine that is expected to allow the delivery of “the right treatment to the right patient at the right time”. There is a general consensus on the necessity of increasing MMI sensitivity by at least a factor of ten in order to exploit its full potential. This project aims at providing a new type of time-of-flight (TOF) PET demonstrator that is expected to drive such a big leap in sensitivity. It can be demonstrated that TOF can introduce a gain in the PET sensitivity that is approximately proportional to the inverse of the resolving time of its photon detectors. Therefore, one way to increase sensitivity is by improving the TOF resolution.

This project includes developments on both TOF-PET hardware and software aimed at improving the TOF resolution beyond the level achievable today. A PET prototype will be constructed based on best performing silicon photomultipliers, the latest scintillating materials and photonic crystals technologies. A scalable data acquisition system based on dedicated ASICs will be developed to handle the high data rate produced by each detector and to fully exploit the sensor performance.

The system will provide timing performances beyond the state of the art, below 200 ps, which will translate into higher imaging sensitivity, higher contrast, lower noise, faster convergence and improved robustness with respect to state of the art TOF-PET alternatives.

Final project summary

Multi-parametric molecular imaging (MMI) is an imaging modality that allowed many of the recent discoveries on new molecular probes and the associated models. MMI is a fundamental pillar of the so-called personalised medicine that is expected to allow the delivery of “the right treatment to the right patient at the right time”. However, there is a necessity of increasing MMI sensitivity by at least a factor of ten in order to exploit its full potential. This project aims at providing a new type of time-of-flight (TOF) PET demonstrator that is expected to drive such a big leap in sensitivity. It can be demonstrated that TOF can introduce a gain in the PET sensitivity that is proportional to the inverse of the resolving time. Therefore, one way to increase sensitivity is by improving the TOF resolution.

This project included developments on both TOF-PET hardware and software aimed at improving the TOF resolution beyond the level achievable today. A PET prototype has been constructed based on best performing silicon photomultipliers, the latest scintillating materials and the potential use of photonic crystals technologies has been explored. A scalable data acquisition system based on dedicated ASICs has been developed to handle the high data rate produced by each detector. In order to work in parallel, event processing (e.g., timestamping and positioning) and data storage are done on the module itself. To balance computational power and cost, a multi-FPGA readout approach has been adopted.

The system has demonstrated to provide timing performances beyond the state of the art, below 200 ps and a spatial resolution below 1 mm, which will translate into higher imaging sensitivity, higher contrast, lower noise, faster convergence and improved robustness with respect to state of the art TOF-PET alternatives. To achieve these results the detector features a continuous scintillator read out by a matrix of 256 SiPMs and data are processed with artificial intelligence.