Main Approaches to Enhance Radiosensitization in Cancer Cells by Nanoparticles: A Systematic Review.

In recent years, high atomic number nanoparticles (NPs) have emerged as promising radio-enhancer agents for cancer radiation therapy due to their unique properties. Multi-disciplinary studies have demonstrated the potential of NPs-based radio-sensitizers to improve cancer therapy and tumor control at cellular and molecular levels. However, studies have shown that the dose enhancement effect of the NPs depends on the beam energy, NPs type, NPs size, NPs concentration, cell lines, and NPs delivery system. It has been believed that radiation dose enhancement of NPs is due to the three main mechanisms, but the results of some simulation studies failed to comply well with the experimental findings. Thus, this study aimed to quantitatively evaluate the physical, chemical, and biological factors of the NPs. An organized search of PubMed/Medline, Embase, ProQuest, Scopus, Cochrane and Google Scholar was performed. In total, 77 articles were thoroughly reviewed and analyzed. The studies investigated 44 different cell lines through 70 in-vitro and 4 in-vivo studies. A total of 32 different types of single or core-shell NPs in different sizes and concentrations have been used in the studies.

Comparison of non-electrophoresis grade with electrophoresis grade BIS in NIPAM polymer gel preparation.

INTRODUCTION: The main objective of this study was to investigate the possibility of replacing electrophoresis cross-linker with non-electrophoresis N, N'-methylenebisacrylamide (BIS) in N-isopropyl acrylamide (NIPAM) polymer gel and its possible effect on dose response. METHODS: NIPAM polymer gel was prepared from non-electrophoresis grade BIS and the relaxation rate (R2) was measured by MR imaging after exposing the gel to gamma radiation from Co-60 source. To compare the response of this gel with the one that contains electrophoresis grade BIS, two sets of NIPAM gel were prepared using electrophoresis and non-electrophoresis BIS and irradiated to different gamma doses. RESULTS: It was found that the dose-response of NIPAM gel made from the non-electrophoresis grade BIS is coincident with that of electrophoresis grade BIS. CONCLUSION: Taken all, it can be concluded that the non-electrophoresis grade BIS not only is a suitable alternative for the electrophoresis grade BIS but also reduces the cost of gel due to its lower price.

Dosimetric properties of N-isopropylacrylamide polymer gel using nonelectrophoresis grade BIS in preparation.

INTRODUCTION: Unlike availability of the different grades of N, N'-methylenebisacrylamide (BIS), electrophoresis is recommended in literature as a crosslinking agent in gel preparation. As the cost of non-electrophoresis grade BIS is much less than that of electrophoresis, the dosimetric characteristics of the of the polymer gel using non-electrophoresis BIS is evaluated in terms of photon energy and dose rate. MATERIALS AND METHODS: To compare the response of this gel with the one that contains electrophoresis grade BIS, two sets of N-isopropylacrylamide (NIPAM) gel were prepared using electrophoresis and non-electrophoresis BIS and irradiated to different gamma doses. RESULTS: It was shown that the dose-response of NIPAM gel made from non-electrophoresis grade BIS is coincident to that of electrophoresis grade BIS. The study of dose response of NIPAM with non-electrophoresis grade BIS as a function of beam energy revealed no dependence on radiation energies of 1.25 MV from 60 Co and 6 MV and 18MV from linear accelerator. It was found that dose rate has no influence on dose response of NIPAM gel with non-electrophoresis BIS. CONCLUSION: Substitution non-electrophoresis grade BIS not only reduces the cost of gel preparation without any adverse effect on its dose response, but also its lower background increases the dynamic range of dose linearity.

Role of gel dosimeters in boron neutron capture therapy.

Gel dosimeters have acquired a unique status in radiotherapy, especially with the advent of the new techniques in which there is a need for three-dimensional dose measurement with high spatial resolution. One of the techniques in which the use of gel dosimeters has drawn the attention of the researchers is the boron neutron capture therapy. Exploring the history of gel dosimeters, this paper sets out to study their role in the boron neutron capture therapy dosimetric process.