Program Information
Dose Enhancement in Nanoparticle-Aided Electron Skin Therapy: A Monte Carlo Study
X Zheng1 , J Chow2*, (1) Ryerson University, Toronto, ON, (2) Princess Margaret Cancer Centre, Toronto, ON
Presentations
TU-C2-GePD-T-2 (Tuesday, August 1, 2017) 10:00 AM - 10:30 AM Room: Therapy ePoster Lounge
Purpose: This study evaluated the dose enhancement due to adding nanoparticles in electron skin therapy. Different types and concentrations of nanoparticles were investigated using the 4 and 6 MeV electron beams.
Methods: Nanoparticles (Au, Pt, I, Ag and Fe₂O₃) were added to heterogeneous phantoms with skin target layers (thicknesses = 0.5–5 mm) in different concentrations (3–40 mg/ml). The phantoms were irradiated by the 4 and 6 MeV electron beams produced by a Varian 21 EX linear accelerator. The 10×10 cm² applicator and cutout were used with source-to-surface distance equal to 100 cm. Monte Carlo simulations (the EGSnrc-based code) were used to calculate doses at target layers with and without nanoparticles. The dose enhancement ratio (DER), defined as the ratio of dose at the target layer with added nanoparticles to the dose at the layer without nanoparticles, were calculated for different types and concentrations of nanoparticles in target layers.
Results: For all nanoparticles in this study, the Au nanoparticles were found to have the highest DER (1.01–1.08) using the 4 MeV electron beams. However, it is found that the variation of DER was affected by the depth of maximum dose of the electron beam and target thickness. For nanoparticles with lower atomic numbers than Au, the DERs were determined in the range of 0.99–1.02 using the 4 and 6 MeV electron beams. The DERs calculated in this study were lower than those in our previous work using the 105 and 220 kVp photon beams in which DERs in the range of 5.2–6.3 were determined.
Conclusion: Nanoparticle addition can produce dose enhancement in electron skin therapy, though the DER is found much lower than using the kV photon beams. Variation of DER is affected by the depth of maximum dose of the electron beam and target thickness.
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