Progress in the development of a tomographic SPECT system for online dosimetry in BNCT

D.M. MINSKY; A. VALDA; A.J. KREINER; A.A. BURLON; S. GREEN; C. WOJNECKI; Z. GHANI

Santiago, Chile

Congreso; VIII Latin American Symposium on Nuclear Physics and Applications; 2009

Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile

Artículo completo enviado y en proceso de evaluación - In boron neutron capture therapy (BNCT) the delivered dose to the patient depends both on the neutron beam characteristics and on the 10B body distribution which, in turn, is governed by the tumor specificity of the 10B drug-carrier. BNCT dosimetry is a complex matter due to the several interactions that neutrons can undergo with the different nuclei present in tissue. However the boron capture reaction 10B(n,?)7Li accounts for about 80 % of the total dose in a tumor with 40 ppm in 10B concentration. Present dosimetric methods are indirect, based on drug biodistribution statistical data and subjected to inter- and intra-patient variability. In order to overcome the consequences of the concomitant high dosimetric uncertainties, we propose a SPECT (Single Photon Emission Tomography) approach based on the detection of the prompt gamma-ray (478 keV) emitted in 94 % of cases from 7Li. For this purpose we designed, built and tested a prototype based on LaBr3(Ce) scintillators. Measurements on a head and tumor phantom were performed in the accelerator-based BNCT facility of the University of Birmingham (UK). They result in the first tomographic image of the 10B capture distribution obtained in a BNCT facility. We are working in improvements toward a clinical system.