A positron emission tomography apparatus based on liquid xenon with time of flight applications

ended

This project presents a new technology for detectors used in positron emission tomography (PET), based on liquid xenon instead of current scintillator crystals. The basic element is a liquid xenon scintillating cell, with its size optimized to maximize the number of gammas that interact in the cell. Silicon photomultipliers read out by low power, low noise customized integrated circuits for time of flight applications will be used as sensors. Xenon is a noble gas which scintillates as response to ionizing radiation. Scintillation is very fast and intense, which results in the possibility of building a PET of good energy and spatial resolution and excellent time resolution. This, in turn, makes possible the measurement of the time-of-flight (TOF), which increases the sensitivity of the detector. Recently, the PI has published a Monte Carlo study of the coincidence resolving time that can be achieved by the PETALO technology, obtaining the promising result of less than 100 ps FWHM, which would be a break-through in the PET scanner field. The low cost of liquid xenon compared to conventional scintillating crystals opens two possible applications: one one hand, a full body PET reducing the cost and with an already better performance than the current technology; on the other hand, a smaller brain scanner, optimized to maximize the improvement in the performance with TOF measurements. This project will demonstrate the technological and commercial feasibility of the proposed technology. For this purpose, first a set of prototypes with two cells will be built to evaluate the resulting performance of the PETALO technology using different kinds of photosensors (UV light sensitive SiPMs versus conventional ones coated with a wavelength shifter). In a second phase, a full ring of the dimensions of a brain scanner will be built, using the technology that has performed better according to the results of this first phase.