The experience of using portable Russian neutron generator for gamma-neutron therapy of domestic animals with malignant tumors

The previously obtained data on the synergetic effects of two beams of different quality allowed us approbate the complex gamma and neutron irradiation scheme in vivo trials. The portable pulse neutron generator (PNG-031) used as the neutron source. The energy of neutron is 14.1 MeV, neutron flux up to 6×109 n/s and neutron pulse duration is 1 µs. The combined schemes using neutron and gamma beams were tested (individual clinical cases) on the 18 small pets (14 dogs and 4 cats in the age from 4 to 18 years) with spontaneous malignant tumors. Pets were irradiated twice per week with 4-6 sessions in course. Each irradiation sessions consist of gamma-irradiation followed by neutrons within 15 min. Single focal dose was 5-8 Gy for gamma and 1.0-1.4 Gy for neutron. The contribution of neutron dose to the total focal dose using 2.5 RBE value was 25-40%. The total dose varied within range from 10.5 to 48 Gy-Eq. The results obtained after full course show that 58% of pets had complete tumor regression and 16% partial tumor regression. We observe the tumor size suppression in 1.5-3 times already after 3-4 irradiation sessions which was coupled with the increasing of general health status of the pets. The normal adjacent tissues reaction for animals with complete and partial tumor regression was minor. The obtained primary results shown a promising possibility to develop the clinically significant technology for combined gamma-neutron therapy using portable neutron generators and prospects of its implementation in clinical practice.