ESTRO 2024 - Abstract Book

S3533

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2024

MC. The dose underneath the metal implants was sorted in descending order as follows: NoExNoOv > NoExOv > ExNoOv in Precision and NoExNoOv > NoExOv ~ ExNoOv in MC. The behaviour of metals between three techniques using MC calculation is generally comparable to Precision TPS calculation and it matches with other research performed in AAA algorithm.

Conclusion:

From the MC calculation in our phantom study, both ExNoOv and NoExOv treatment planning technique methods are proven to have similar behaviour in calculating the dose of tissues underneath metal along the beam path with measured dose. In clinical situation, it affects the target and nearby OARs dose when the entry beam path is blocked by metal implants. Using NoExOv technique one should be aware of the composition and geometry of metallic implant as the target dose underneath the metal interface can be underestimated if one accidentally contoured an exaggerated bulked metal. Using ExNoOv technique can be another option in this case without the need of contouring metallic implant. This study only studies the effect of small metallic regular rods. Other shapes like mesh, sheet, or bulk metallic implants are subjected to further investigation.

Keywords: Monte Carlo, metallic implant, Radixact®

References:

Gnanasambandam, Amirtharaj. "Effects of metal implants and validation of four treatment planning methods used for radiotherapy dose calculation." reports of practical Oncology and radiotherapy 27.5 (2022): 821-831.

Mullins, John P., et al. "Treatment planning for metals using an extended CT number scale." Journal of applied clinical medical physics 17.6 (2016): 179-188.

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Poster Discussion