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Nontoxic electron collimators
Dylan Yamabe Breitkreutz1, Lawrie Skinner1, Stephanie Lo1
1Department of Radiation Oncology, Stanford University, Stanford, California, USA.
Journal of Applied Clinical Medical Physics
|September 4, 2021
Summary
Nontoxic electron collimation technologies, including tungsten-silicone and 3D printed cutouts, show promise for clinical use. These novel methods offer improved dose uniformity and are dosimetrically equivalent to current standards.
Area of Science:
- Medical Physics
- Radiation Oncology
- Materials Science
Background:
- Clinical electron therapy requires precise dose shaping and shielding.
- Current collimation technologies, such as cerrobend, have limitations in terms of toxicity and flexibility.
- Development of advanced, nontoxic electron collimation is crucial for improving patient treatment and safety.
Purpose of the Study:
- To develop and evaluate novel, nontoxic electron collimation technologies for clinical applications.
- To assess the dosimetric properties and clinical feasibility of tungsten-silicone composite and 3D printed electron cutouts.
Main Methods:
- Investigated tungsten-silicone composite for transmission, dose uniformity, and profile analysis.
- Evaluated 3D printed electron cutouts against standard cerrobend cutouts for surface dose, output, and field size.
- Developed quality assurance tests for 3D printed cutouts, including mass, imaging, and drop testing.
Main Results:
- Tungsten-silicone shields demonstrated sharper dose profiles (2-3 mm penumbra) compared to cerrobend (7-8 mm).
- 3D printed cutouts showed dosimetric equivalence to cerrobend, with maximum differences in output, surface dose, and FWHM below 2%.
- Tungsten-silicone provided significant electron intensity reduction (~90%) at clinically relevant energies and thicknesses.
Conclusions:
- Both tungsten-silicone and 3D printed cutouts are feasible for clinical electron therapy.
- Tungsten-silicone exhibits adequate density, flexibility, and uniformity for skin shielding.
- 3D printed cutouts are dosimetrically equivalent and robust for clinical handling, offering a viable alternative to cerrobend.
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