Speaker
Description
Author: Vladimir Skorkin
Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia
Corresponding Author: skorkin@inr.ru
Contrast-enhanced radiotherapy allows to enhance the radiation dose absorbed by the tumor when using the hard elements (I, Gd, Au, Bi, etc.) for a photon absorption [1]. The dose-enhancing agents have a better absorption capacity, than biological tissues and thus sparing the surrounding healthy cells. In [2], an increase dose absorbed by iodinated water (for 50 mg/ml iodine concentrations) was obtained at using bremsstrahlung photons generated by the clinical linear electron accelerator SL75-5MT. Normally, dose-enhancing agent concentrations employ up to 15 mg/ml.
In our work, we investigated the possibility of using metal-organic composites containing dose-increasing agents to increase the absorption of SL75-5MT bremsstrahlung photons. The present study aims to assess feasibility of using of the metal-organic composites SL75-5MT bremsstrahlung photons to increase radiation absorbed by [3]. The linear accelerator 0.5-4.5 MeV photons (80% of total flux and 2 Gray/min absorbed dose) created secondary X-rays and electrons in the dose-enhancing metallic agents of the metal-organic composites. This is enhanced the radiation dose absorbed by the tumor. The dose absorbed by tissue-equivalent phantom with metallic agents (Cd, Au, W, Bi, Pb) was measured by PTW MULTIDOS dosimetry with clinical ionization chambers. In addition, a gamma radiation from the phantom were measured using BDMG-08R gamma detectors. For Au, Bi, Pb dose-enhancing agents the absorbed dose increased by 10-20%. The significant increase in the absorbed dose (> 50%) was observed from d(γ,n)p reaction when using deuterated water instead of tissue-equivalent phantom. Therefore, it is possible to employing deuterated water for photon energy spectra of SL75-5MT clinical accelerator in order to reach a therapeutically significant effect.
References:
1. Koryakin S.N. at al, Rossiyskiy biotherapevticheskiy jurnal. 15, 52 (2016).
2. Vorobyeva E.S. at al, Bulletin of RSMU. 4, 57 (2017).
3. Burmistrov Yu.M. at al, J. Surface Investigat. 13, 195 (2019).
