Speaker
Dr
Alexander Zaboronok
(University of Tsukuba)
Description
The main treatment effect of boron neutron capture therapy (BNCT) depends on the release of alpha-particles inside tumor cells, and direct measurement of the absorbed dose becomes impossible. To solve the problem of absorbed dose evaluation, measurement of gamma-rays produced by golden foils that are placed close to the irradiated samples and activated by neutrons is typically used. Accumulation of radioactive 198Au isotope with the 2.7-day half-life releasing 411 keV gamma-rays provides with the data for absorbed dose calculation. We propose using both boron and gold compounds together for direct absorbed dose evaluation in tumor cells.
T98G (human glioma) cells were incubated with gold nanoparticles (GNPs, 50 ppm) and boron-phenylalanine (BPA) at B-10 concentrations of 0, 10, 20, 40 ppm over 24 hours, placed in plastic vials in the acryl phantom, irradiated with neutrons at the accelerator during 2-3 hours with 2.0 MeV proton energy and 2-3 mA proton current, analyzed by a gamma spectrometer, and seeded for colony-forming assay. Complex boron-gold compounds design was also introduced.
BNCT effect was shown by decrease in cell colony formation with increase in boron concentrations. 411 keV gamma-rays released from activated gold-containing samples were measured, and the following formula for absorbed dose calculation was proposed: D=(k*N*n)/m, where D is the boron dose in GyE, N is the number of activated gold atoms, n is the boron concentration in ppm, m is the mass of gold in grams, and k is the coefficient dependent on the depth (cm) to the sample in the acryl phantom. Thus, cells with 129.8±7.3 µg of gold obtained 12.98 GyE of radiation. We are the first to introduce absorbed dose estimation method using gold and boron compounds, and we believe that such method can be further modified into isotope scanning to provide data on absorbed dose during BNCT.
The work was supported by the Russian Foundation for Basic Research (project 18-29-01007) and the University of Tsukuba Research Foundation Support Program of 2019 (Type A).
Primary author
Dr
Alexander Zaboronok
(University of Tsukuba)
Co-authors
Ms
Liudmila Mechetina
(Institute of Molecular and Cell Biology)
Ms
Olga Volkova
(Institute of Molecular and Cell Biology)
Prof.
Sergey Taskaev
(Budker Institute of Nuclear Physics)
Dr
Vladimir Kanygin
(Novosibirsk State University)
