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Author Ouyang, Z. ♦ Ngwa, W. ♦ Liu, B. ♦ Sajo, E. ♦ Yasmin-Karim, S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword APPLIED LIFE SCIENCES ♦ RADIATION PROTECTION AND DOSIMETRY ♦ BEAMS ♦ BIOLOGICAL MATERIALS ♦ BIOMEDICAL RADIOGRAPHY ♦ COMPUTERIZED SIMULATION ♦ CONCENTRATION RATIO ♦ DAMAGE ♦ IN VITRO ♦ MONTE CARLO METHOD ♦ NANOPARTICLES ♦ NEOPLASMS ♦ POSITRON COMPUTED TOMOGRAPHY ♦ RADIOTHERAPY ♦ TITANIUM OXIDES ♦ TUMOR CELLS
Abstract Purpose: This study investigates the feasibility of exploiting the Cerenkov radiation (CR) present during external beam radiotherapy (EBRT) for significant therapeutic gain, using titanium dioxide nanoparticles (titania) delivered via a new design of radiotherapy biomaterials. Methods: Recently published work has shown that CR generated by radionuclides during PET imaging could substantially enhance damage to cancer cells in the presence of 0.625 µg/g titania. We hypothesize that equal or greater damage can be achieved during EBRT. To test this hypothesis, Monte Carlo simulation was done using GEANT4 in order to get the total CR yield inside a tumor volume during EBRT compared to that of the radionuclides. We considered a novel approach where a sufficiently potent concentration of the titania was delivered directly into the tumor using radiotherapy biomaterials (e.g. fiducials) loaded with the titania. The intra-tumor distribution/diffusion of titania released from the fiducials was calculated. An in-vitro MTS assay experiment was also carried out to establish the relative non-toxicity of titania for concentrations of up to 1 µg/g. Results: For a radiotherapy biomaterial loaded with 15 µg/g of 2-nm titania, at least 0.625 µg/g could be delivered through out a tumor sub-volume of 2-cm diameter after 14 days. This concentration level could inflict substantial damage to tumor cells during EBRT. The Monte Carlo results showed the CR yield in tumor by 6 MV radiation was higher than the radionuclides and hence potentially greater damage may be obtained during EBRT. No significant cell viability change was observed for 1 µg/g titania. Conclusion: Altogether, these preliminary findings demonstrate a potential new approach that can be used to take advantage of the CR present during megavoltage EBRT to boost damage to tumor cells. The results provide significant impetus for further experimental studies towards development of nanoparticle-aided EBRT powered by the Cerenkov effect.
ISSN 00942405
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-15
Publisher Place United States
Journal Medical Physics
Volume Number 43
Issue Number 6


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