Neutron and gamma-ray imaging for real-time range verification and image guidance in particle therapy

Project summary

Particle therapy (PT) is an emerging radiation therapy modality offering highly conformal treatment plans as compared to conventional radiation therapy, contributing to spare healthy tissue during treatment. This is mainly due to the finite range of particles in tissue and the steep dose gradient toward the end of their range. An important challenge associated with PT is the considerable uncertainties in the particle ranges in tissue predicted by treatment planning systems in addition to those resulting from tissue heterogeneities, anatomical changes as well as inter- and intra-fractional organ motion. These uncertainties result in increased distal treatment margins in clinical protocols. Thus, it has not yet been possible to exploit the full potential of the finite range of protons in tissue, especially when tumors are located near organs at risk. There is therefore a consensus that it is of great importance to monitor the range of particles during treatment with high precision (~1-2mm). Range verification techniques will also allow on-line monitoring of the delivered dose to patient.

We propose, for the first time, the development of a compact, high-efficiency single volume scatter camera (SVSC) based on optically segmented arrays of organic scintillators. The SVSC will be utilized for the detection and subsequent imaging of secondary neutrons and prompt gamma-rays (PGs) produced in nuclear interactions. The SVSC will be the first of its kind in PT offering "unification" of neutron and PG imaging in a single device with potentially revolutionizing improvements in achievable counting statistics to allow range and dose verification on a spot-by-spot basis, including weaker spots. To achieve the objective of the NOVO project, we will (1) perform a model-based design evaluation of the SVSC, (2) develop methods for optimal particle discrimination and (3) perform tests in clinically realistic conditions with a first functional prototype SVSC.