Investigation of the gold nanoparticles effects on the prostate dose distribution in brachytherapy: gel dosimetry and Monte Carlo method

Abstract

PurposeIn this work, gold nanoparticles (GNPs) were embedded in the MAGIC-f polymer gel irradiated with the 192Ir brachytherapy sources.Material and methodsAt the first plexiglas phantom was made as the human pelvis. The GNPs were synthesized with 15 nm in diameter and 0.1 mM (0.0197 mg/ml) in concentration by using a chemical reduction method. Then, the MAGIC-f gel was synthesized. The fabricated gel was poured into the tubes located at the prostate (with and without the GNPs) locations of the phantom. The phantom was irradiated with 192Ir brachytherapy sources for prostate cancer. After 24 hours, the irradiated gels was read by using Siemens 1.5 Tesla MRI scanner. Following the brachytherapy practices, the absolute doses at the reference points and isodose curves were extracted and compared by experimental measurements and Monte Carlo (MC) simulations.ResultsThe mean absorbed doses in the presence of the GNPs in prostate were 14% higher than the corresponding values without the GNPs in the brachytherapy. The gamma index analysis (between gel and MC) using 7%/7 mm was also applied to the data and a high pass rate achieved (91.7% and 86.4% for analysis with/without GNPs, respectively).ConclusionsThe real three-dimensional analysis shows the comparison of the dose-volume histograms measured for planning volumes and the expected one from the MC calculation. The results indicate that the polymer gel dosimetry method, which developed and used in this study, could be recommended as a reliable method for investigating the dose enhancement factor of GNPs in brachytherapy.

Radiosensitization of breast cancer cells using AS1411 aptamer-conjugated gold nanoparticles

“…For electron beams at MeV energies, there are controversies between theoretical and experimental works. Considering the previous observations, regardless of the physical mechanisms of the effect of GNPs, studies have agreed on the radiosensitizing effect of GNPs in MeV energies (43,(47)(48)(49).…”

“…In recent years, many studies have been done on the radiosensitizing and dose enhancement effect of GNPs. The main mechanisms of GNP-induced radiosensitization are likely dependent on multiple variables including nanoparticle size and the shape of nanoparticle (41,42), and its surface coating (31) ; radiation dose and the applied energy (8,29,43) . Most of the studies have emphasized on the radiosensitizing effect of GNPs and the dose enhancement of GNPs at kilo voltage (KV) energies of photon beams because of the dominance of photoelectric effect and its' consequences at such energies (32,(44)(45)(46).…”

Radiosensitization of breast cancer cells using AS1411 aptamer-conjugated gold nanoparticles

“…For electron beams at MeV energies, there are controversies between theoretical and experimental works. Considering the previous observations, regardless of the physical mechanisms of the effect of GNPs, studies have agreed on the radiosensitizing effect of GNPs in MeV energies (50,52,54) while dose enhancement for electron beams is negligible based on the physical characteristics. In vitro studies (33) have shown the speci c radiosensitization in MDA-MB-231 cells, comparable with sensitizer enhancement ratio at kV and MeV energies.…”

“…In recent years, many studies have been done on the radiosensitizing and dose enhancement effect of GNPs. GNP-induced radiosensitization is likely dependent on multiple variables including nanoparticles size and the shape (13,48,49) and its surface coating; radiation dose and the applied energy (7,33,50). Most of the studies have emphasized on the radiosensitizing effect of GNPs and the dose enhancement of GNPs at kilo voltage (KV) energies of photon beams because of the dominance of photoelectric effect and its consequences at such energies (36,(51)(52)(53).…”

Gold Nanoparticles in Radiotherapy and Recent Progress in Nanobrachytherapy

“…In an effort to overcome the challenge of bridging the gap between simulation models and experimental data, Khosravi et al performed dose measurements on a system made of GNPs embedded in a polymeric gel (MAGIC‐f), irradiated with high‐dose‐rate brachytherapy sources ( 192 Ir) . The effect of GNPs on dose distributions in the prostate was assessed by experimental measurements, which were compared to a Monte Carlo simulation.…”