The possibility of generation of secondary ionizing radiation on tantalum oxide nanoparticles in radiation therapy of malignant tumors

The administration of radiation sensitizer into a tumor succeeded by ray treatment leads to the additional secondary radiation inside the neoplasm that improves the effect of the ray treatment. Methods. Measuring the dose of ionizing radiation was conducted by using the phantom (WP 600). The 2.5 % suspension of nanoparticles (NPs) of tantalum oxide (Ta₂O₅) or control solution (0.9 % NaCl solution) were placed into a spherical sample. Dimensions of NPs were determined with the tool Zetasizer NanoZS and constituted 71±1 nm (А) и 81±1 nm (В). Со⁶⁰ was used as a source of radiation. The measuring was carried out with the ionization chamber FC65-P, which recorded the total intensity of Y-radiation. The measuring was carried out at the open gate, the passage of Y-camera under the test specimen at a distance of 0.5 cm. Data were processed in Wolfram Mathematica 9.0. Results. The total radiation for samples containing NPs Ta₂O₅ was higher than those obtained in the measurement of ionizing radiation by a 0.9 % solution of NaCl. The increase for particles with a size of 65 nm was 5.5 % for particles with a size of 71 nm - 5.2 %, for a particle with a size of 81 nm - 7 %. The reason for increase in the emission intensity when passing hard Y-radiation through the low Ta₂O₅ is the generation of the secondary low-energy ionizing radiation. Conclusions. NPs Ta₂O₅ is a promising medicine for the treatment of local radio modification malignancies.

ray treatment, radio modification, gamma-quantum, Compton Effect

1. Работа выполнена при финансовой поддержке программы «Дальний Восток» (грант 14-NSC-006)

2. Apanasevich V., Avramenko V., Lukyanov P. [et al.]. Enhance the absorption of gamma-ray energy inside the tumor using gold nanoparticles and iodine particles // Cancer and Oncology Research. 2014. Vol. 2, No. 2. P. 17-20.

3. Bonnet C., Toth E. Smart contrast agents for magnetic resonance imaging // CHIMIA International Journal for Chemistry. 2016. Vol. 70, No. 1, P. 102-108.

4. Chelkowski S., Bandrauk A.D., Corkum P.B. Photon momentum sharing between an electron and an ion in photoionization: from one-photon (photoelectric effect) to multiphoton absorption // Phys. Rev. Lett. 2014. Vol. 113, No. 26. P. 263005.

5. Gambini D.J. Basic concepts of radiology physics // J. Radiol. 2010. Vol. 91, No. 11 ( Pt 2). P. 1186-1188.

6. Jain S., Hirst D. G., O'Sullivan J.M. Gold nanoparticles as novel agents for cancer therapy // Br. J. Radiol. 2012. Vol. 85, No. 1010. P. 101-113.

7. Mitchell J., Knight R.T., Kimlin K. Effects of iodinated contrast media on radiation therapy dosimetry for pathologies within the thorax // The Radiographer. 2006. Vol.53, No. 2. P. 30-34.