ESTRO 2023 - Abstract Book

S638

Monday 15 May 2023

ESTRO 2023

Conclusion The results of the experiments carried out supported the development of a multi-thickness microdosimeter. The novel detector will allow an accurate characterisation of the beam quality along the whole depth-dose profile, using the optimal detector thickness for each region of the curve. Further, the detector will allow to carry out the first experimental study on the influence of the sensitive volume on the microdosimetric measurement. The characterisation of the detector by means of IBIC analysis, and experiments in clinical proton and carbon beams are planned soon.

OC-0772 Development of a gamma-ray detector for dose monitoring in BNCT A. Caracciolo 1 , D. Di Vita 1 , T. Ferri 2 , M. Carminati 2 , N. Protti 3 , S. Altieri 4 , F. Camera 5 , C. Fiorini 2

1 Politecnico di Milano , Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy; 2 Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milan, Italy; 3 Università di Pavia, Dipartimento di Fisica, Pavia, Italy; 4 Università di Pavia, Dipartimento di Fisica , Pavia, Italy; 5 Università degli Studi di Milano Statale, Dipartimento di Fisica, Milan, Italy Purpose or Objective We report the experimental validation of a gamma ray detection prototype as a basic element for a SPECT system for dose monitoring in Boron Neutron Capture Therapy (BNCT). BNCT is a targeted radiotherapy technique where tumor cells are loaded with 10B-enriched molecules and then irradiated with thermal neutrons. Reactions following neutron capture by 10B produce damage limited to the diameter of the single tumoral cell. A fundamental issue to fully exploit this excellent targeting capability is the in-vivo and real time measurements of 10B captures. This can be achieved by detecting the 478 keV prompt gamma rays that are emitted in 94% of the 10B(n, α )7Li reactions. The intensity of the 478 keV gamma rays is proportional to the boron local dose, thus a SPECT system can be used to monitor the 3D treatment effect in real time. However, the detection of these gamma rays is very challenging because of the high intensity neutron sources required in BNCT, that leads to a sever background of neutrons and secondary gamma rays. We propose the development of a SPECT apparatus consisting of multiple LaBr3 scintillator crystal detectors. We report the results achieved with a first prototype detector. Materials and Methods The proposed detection module is based on a 2 inches cylindrical LaBr3(Ce+Sr) scintillator crystal, coupled with a matrix of 8x8 Silicon Photomultipliers (SiPMs), read by 4 custom ASICs. To validate the spectroscopic capabilities of the detector