Stacked Positron Emission Tomography Sensors

Positron emission tomography (PET) is a functional imaging technique that is used to observe metabolic processes in the body through nuclear imaging of the decay processes of radioactive isotopes injected into patients as biologically-active tracer molecules. PET systems detect pairs of gamma rays emitted indirectly by positron-emitting radionuclide tracer molecules. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis.
PET scanners are conventionally constructed by arranging large arrays of scintillator crystals in a ring around a patient. The scintillators stop the gamma rays converting them into flashes of blue wavelength visible light which can then be detected by ultra-sensitive optical detectors such as photomultiplier tubes (PMTs). In recent years, there is a drive to replace PMTs with a solid-state technology such as silicon photomultipliers (SiPMs) based on arrays of SPAD detectors. This move is motivated by the desire to reduce cost and size of these scanners as well as to render them compatible with the intense magnetic fields of MRI which disturb vacuum-tube technologies such as PMTs.
The University of Edinburgh has been engaged in the latest evolution of solid-state PET scanners (http://www.spadnet.eu) which is to develop smart digital SiPMs (dSiPMs) based on CMOS technology. This PhD project will propose and integrate new architectures of smart dSiPM in the latest 3D stacked CMOS manufacturing technologies accessed through the ENIAC-POLIS project (http://polis.minalogic.net/index.php). The student will build on developments within the CMOS Sensors and Systems group of the world’s fastest time-to-digital converter (“FlashTDC”) and embed these within triggering and counting systems for realisation of a tileable PET scanner module. The sensors will be electro-optically tested within our laboratories and where possible in collaboration within the nuclear testing facilities of our SPADnet partners. The project can benefit from our research collaboration agreement from STMicroelectronics and support from the Quantum Hub in Quantum Enhanced Imaging (http://quantic.ac.uk).

This is a four-year PhD that will be undertaken within the Centre for Doctoral Training in Intelligent Sensing and Measurement. See http://www.cdt-ism.org for programme details and information on how to apply.