Gamma-spectrometer for dose measurement in Neutron Capture Therapy

SiPM compactness and good radiation hardness to neutron radiation make this photodetector a promising device for Neutron Capture Therapy (NCT) of cancer.

Measurement of the dose received by the patient during the NCT with high accuracy dominates the success of this technique. Today there is no reliable method of dose measurement in the case of thermal neutron irradiation of cancer formations, where neutron capture agent-pharmaceuticals containing 157Gd or 10B are introduced. These nuclei have a very large thermal neutron absorption cross section of about 105 barns. The accumulation of these substances in carcinoma in the body of a patient depends on many parameters (speed of their removal from the body, carcinoma volume, etc.). As a rule, it is not possible to estimate accurately the concentration of pharmaceuticals introduced in carcinoma. The proposed researches allow us to develop a new method for measurement of the concentration of these substances and the dose rate at NCT by spectrometric measurements of gamma radiation, accompanying the capture of thermal neutrons by 157Gd or 10B. To implement this method, it is necessary to devise gamma spectrometers, that allow registration of gamma-lines arising from the interaction of neutrons with nuclei 157Gd or 10B. The gamma spectrometer will consist of a LaCl3 crystal read out by SiPMs with energy resolution of about 3%.

A method for measuring received dosages in biological objects will be developed and tested at the MEPhI nuclear reactor. The Russian Research Cancer Center will be involved in these studies.