Behnaz Babaye Abdollahi
1,2,3 
, Reza Malekzadeh
2, Fatemeh Pournaghi Azar
4 , Fatemeh Salehnia
5, Ali Reza Naseri
6, Marjan Ghorbani
7 , Hamed Hamishehkar
1 , Ali Reza Farajollahi
1,2,6* 1 Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
2 Department of Medical Physics, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
3 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.
4 Department of Operative Density, Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
5 Research Center for Evidence Based Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
6 Imam Reza Educational Hospital, Radiotherapy Department, Tabriz University of Medical Sciences, Tabriz, Iran.
7 Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
*Corresponding Author: Imam Reza Educational Hospital, Radiotherapy Department, Tabriz University of Medical Sciences, Tabriz, Iran. Email farajollahia@tbzmed.ac.ir
Abstract
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.