Assessing an accelerator design for treating different tumor targets with AB-BNCT

M.S. HERRERA; S. GONZÁLEZ; D.M. MINSKY; N. MOJSIEJCZUK

Hsinchu, Taiwan

Congreso; 6th Young Researcher Boron Neutron Capture Meeting; 2011

National Tsing Hua University

PurposeBoron Neutron Capture Therapy (BNCT) has been used clinically in several countries to treat patients with different pathologies, for example, high-grade gliomas, metastatic and cutaneous melanoma, head and neck tumors, mesothelioma. Considerable effort is going into the development of an accelerator-based neutron source in Argentina. The machine under construction will upgrade the treatment facilities of the A. H. Roffo Oncology Institute. It is expected that this implementation will be used for many different BNCT treatments and experimental purposes. In this work an evaluation of the actual accelerator- based BNCT design is considered to test the scope of such a therapy in general tumor targets.MethodologyIn previous work we have studied the treatment planning capability of different accelerator designs for a real patient with glioblastoma multiforme and it was shown that all designs lead to feasible clinical treatments. In this work we considered one of those configurations to study the possibility of treating different BNCT tumor targets considering a range of tumor sizes and locations. The performance of an actual AB-BNCT design was assessed using imaging studies of real patients through treatment planning and Monte Carlo simulations. Neutron transport was simulated from the accelerator lithium target for the 7Li(p,n)7Be nuclear reaction. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. We have also considered, when necessary, the presence of a bolus between the accelerator exit port and the patient, modifying the depth dose in the tissues. The evaluation of the results obtained from the simulations was made using several figures of merit that include both 3D dose distributions for normal and tumor tissues, the irradiation time, normal tissue complication probability models (NTCP), among others.Results and ConclusionThe results showed that the proposed accelerator is suitable for treating different targets in BNCT. In particular, for the cutaneous melanoma cases analyzed in this work, irradiation times and delivered tumor doses were similar to those achieved in the melanoma patients treated in the RA-6 experimental reactor in Argentina. Regarding studied brain cancer cases, the derived NTCPs for skin and mean brain doses were substantially reduced compared to previous results with the addition of a cone at the exit port of the accelerator design, thus improving the general performance of the treatments.