Dose enhancement in radiotherapy by novel application of gadolinium based MRI contrast agent nanomagnetic particles in gel dosimetry
N. Riyahi alam
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© 2015 Hydrogen Energy Publications, LLC. The ultimate goal of radiotherapy is to eradicate tumors while preserving normal tissues. One of the novel ways to achieve this goal is increasing tumor injuries by accumulating high atomic number (z) elements preferentially in tumor cells during irradiation. Recently, there has been a growing interest in increasing the performance of radiation therapy using radiocontrast nanoagents. Gadolinium based nanoparticles are a promising and more feasible candidate for multimodal dose enhancement studies. Gadolinium is not only a conventional MRI contrast agent but also behaves as radiosensitizer, making it an attractive alternative to other high-z elements used in image guided radiotherapy and targeted therapies. Herein, dose enhancement in the presence of 0.2 mM gadolinium nanoparticles ( < 40 nm) in MAGIC-F gel filled phantoms was investigated. We also quantified the effects of energies and distances from the source on the dose enhancement factor. Irradiation was carried out by an Iridium-192 radioactive source (0.38 MV) and a 6 MV linear accelerator. Results showed dose enhancement of approximately 15% ± 0.01 at 1 cm from the Iridium-192, to 22% ± 0.02 at 2 cm, whereas this amount is 3.8% ± 0.002 per Gy for external beam radiotherapy with 6 MV photon beams. Our study approved the radiosensitization property of gadolinium based nanoparticles in brachytherapy and external beam radiotherapy.