Dosimetric evaluation of ABS, PLA and NR boluses for electron radiotherapy

Huda Haddad; Huda Haddad

doi:10.3934/biophy.2026001

AIMS Biophysics

2026, Volume 13, Issue 1: 1-20. doi: 10.3934/biophy.2026001

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Research article

Dosimetric evaluation of ABS, PLA and NR boluses for electron radiotherapy

Huda Haddad ^,

Department of Applied Physics, Tafila Technical University, Tafila, 66110, Jordan

Received: 06 November 2025 Revised: 05 January 2026 Accepted: 08 January 2026 Published: 14 January 2026

Purpose
This study aims to compare the dosimetric characteristics of 3D-printed bolus materials acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) with recently introduced natural rubber (NR) bolus.
Materials and Methods
We employed Monte Carlo simulation to evaluate ABS, PLA, and NR boluses of thicknesses 0.5, 1.0, and 1.5 cm under 6, 9, and 16 MeV electron beam irradiation. Percentage depth dose (PDD) data was analyzed to evaluate dosimetry parameters. Dosimetric stability under varying air-gap conditions was assessed by analyzing PDD curves under air-gap sizes of (0, 1, 3, 5 mm).
Results
NR and ABS showed similar dosimetric profiles, whereas PLA showed enhanced deeper-tissue protection and provided 0.7–10.2% higher surface dose (SD). PLA also exhibited the highest stability, with SD and R₉₀ deviations limited to 1% and 1.2%, respectively, under varying air-gap sizes. At 6 and 9 MeV, a 0.5 cm bolus failed to provide a single dose of 90% of maximum dose for nearly all tested materials.
Conclusion
NR demonstrated comparable dosimetric performance to ABS, serving as a viable substitute. PLA was optimal for maximizing SD and distal tissue sparing while exhibiting the lowest air-gap sensitivity. For tumors located several centimeters deep from the surface, 16 MeV electron beams were suitable. Furthermore, Dual hotspots were identified a substantial risk of localized normal tissue toxicity.
- ABS,
- bolus,
- electron bolus,
- electron radiotherapy,
- Monte Carlo simulation,
- natural rubber,
- PLA
Citation: Huda Haddad. Dosimetric evaluation of ABS, PLA and NR boluses for electron radiotherapy[J]. AIMS Biophysics, 2026, 13(1): 1-20. doi: 10.3934/biophy.2026001

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Abstract

Purpose

This study aims to compare the dosimetric characteristics of 3D-printed bolus materials acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) with recently introduced natural rubber (NR) bolus.

Materials and Methods

We employed Monte Carlo simulation to evaluate ABS, PLA, and NR boluses of thicknesses 0.5, 1.0, and 1.5 cm under 6, 9, and 16 MeV electron beam irradiation. Percentage depth dose (PDD) data was analyzed to evaluate dosimetry parameters. Dosimetric stability under varying air-gap conditions was assessed by analyzing PDD curves under air-gap sizes of (0, 1, 3, 5 mm).

Results

NR and ABS showed similar dosimetric profiles, whereas PLA showed enhanced deeper-tissue protection and provided 0.7–10.2% higher surface dose (SD). PLA also exhibited the highest stability, with SD and R₉₀ deviations limited to 1% and 1.2%, respectively, under varying air-gap sizes. At 6 and 9 MeV, a 0.5 cm bolus failed to provide a single dose of 90% of maximum dose for nearly all tested materials.

Conclusion

NR demonstrated comparable dosimetric performance to ABS, serving as a viable substitute. PLA was optimal for maximizing SD and distal tissue sparing while exhibiting the lowest air-gap sensitivity. For tumors located several centimeters deep from the surface, 16 MeV electron beams were suitable. Furthermore, Dual hotspots were identified a substantial risk of localized normal tissue toxicity.

Conflict of interest

The author declares no conflict of interest.

Author contributions

The author is solely responsible for all aspects of this research, including the study's conception, design, methodology, data acquisition, analysis, interpretation, and the writing of the manuscript.

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