An Optimized Method for Evaluating the Potential Gd-Nanoparticle Dose Enhancement Produced by Electronic...

Area of Science:

• Medical Physics
• Nanotechnology
• Radiation Oncology

Background:

• Electronic brachytherapy utilizes low-energy X-rays for targeted radiation delivery.
• Gadolinium nanoparticles (Gd-NPs) are investigated as radiosensitizers to enhance radiation dose deposition.
• Understanding dose enhancement from Gd-NPs is crucial for optimizing treatment efficacy.

Purpose of the Study:

• To develop and validate an experimental method for quantifying Gd-NP dose enhancement in electronic brachytherapy.
• To determine optimal Gd-NP concentrations for maximizing dose enhancement at specific beam energies (50 kVp and 70 kVp).
• To differentiate between dose enhancement and attenuation effects.

Main Methods:

• Utilized delaminated radiochromic films and a Poly(methyl methacrylate) (PMMA) phantom.
• Employed thin Mylar filters (2.5 μm and 12 μm) to separate Gd suspension from the radiosensitive film.
• Evaluated dose enhancement across varying Gd-NP concentrations (10, 20, 30 mg/mL) and beam qualities (50 kVp, 70 kVp).

Main Results:

• At 70 kVp, dose increments of 6±6%, 22±7%, and 9±7% were observed at 10, 20, and 30 mg/mL Gd-NP concentrations, respectively.
• No dose increase was recorded at 50 kVp, suggesting K-edge interaction is key for enhancement.
• Using a 12 μm Mylar filter, K-edge dose enhancement reached 29±7% and 34±7% at 20 and 30 mg/mL, respectively.

Conclusions:

• An optimized method for quantifying Gd-NP dose enhancement in electronic brachytherapy was established.
• Gd-NP concentration significantly influences dose enhancement, with K-edge interactions playing a critical role at lower energies.
• Results indicate a dose enhancement proportional to Gd concentration, offering potential for improved radiotherapy outcomes.