METHOD

Feasibility of using 6 MV photon beams in contrast-enhanced radiotherapy

Vorobyeva ES1, Lipengolts AA1,2,3, Cherepanov AA2, Grigorieva EYu2, Nechkina IN2, Kalygina NS2, Sokovikov AV4, Kulakov VN1, Sheino IN1
About authors

1 Laboratory of radiotherapy methods and technologies, Department of Medical Radiation Technologies,
A. I. Burnazyan Federal Medical Biophysical Center, Moscow, Russia

2 Laboratory of radionuclide and radiation technologies in experimental oncology, Research Institute of Clinical and Experimental Radiology,
N. N. Blokhin National Medical Research Center of Oncology, Moscow, Russia

3 National Research Nuclear University MEPhI, Moscow

4 MedService Ltd., Moscow, Russia

Correspondence should be addressed: Alexey A. Lipengolts
Kashirskoe shosse, d. 24, Moscow, Russia, 115478; ur.liam@stlognepil

About paper

All authors' contribution to this work is equal: selection and analysis of literature, research planning, data collection, analysis, and interpretation, drafting of a manuscript, editing.

Received: 2017-08-25 Accepted: 2017-08-30 Published online: 2017-10-31
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Contrast-enhanced radiotherapy (CERT) is a type of radiation therapy used to enhance the radiation dose absorbed by the tumor while sparing surrounding healthy tissues. The present study aims to assess feasibility of using 6 MV photons to increase radiation absorption in CERT. The dose absorbed by iodinated water was directly measured by ferrosulphate dosimetry. Concentrations of iodine (a dose-enhancing agent) ranged from 2.5 to 50 mg/ml. Solutions were exposed to 5 Gy radiation generated by the clinical linear accelerator SL75-5MT (Russia). The radiation dose applied did not account for increased absorbance due to the presence of iodine atoms. No reliable increase in the absorbed dose was observed for iodine concentrations ranging from 2.5 to 20 mg/ml. For 50 mg/ml concentrations the absorbed dose increased by 13% ± 5 % (p < 0.05). Normally, dose-enhancing concentrations observed in CERT studies range from 2.5 to 15 mg/ml, therefore, as demonstrated by our findings, employing 6 MV photon energy spectra in order to reach a therapeutically significant effect is unreasonable.

Keywords: contrast-enhanced radiotherapy, ferrosulphate dosimetry, megavolts radiation, dose enhancement factor

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