ESTRO 2024 - Abstract Book

S4321

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

The mean (range) time between two subsequent parameter sets broadcasted to DoseTracker was 306.3ms ([13.0;364.1]ms) for prostate and 343.3ms ([14.0;364.3]ms) for LN. DoseTracker finished the dose calculation before arrival of the next parameter set in all but one case for both target volumes, demonstrating sufficient calculation speed for real-time dose reconstruction for high-risk prostate cancer radiotherapy. DoseTracker’s calculations agreed well with the TPS with a root-mean-square error in prostate CTV ΔD 99.5% of 1.1%-points (range: [-1.1;1.9]%-points) and in LN CTV ΔD 98% of 0.3%-points (range: [-4.6;1.2]%-points).

Conclusion:

This study presents the first dose reconstruction accounting for the differential 6DoF prostate and LN motion. Notable dose distortions were found for single fractions, which tended to average out after all imaged fractions. The applied dose reconstruction software, DoseTracker, was shown to be sufficiently fast for real-time application and its dose calculation accuracy was for the first time benchmarked against a clinical TPS for a cohort of high-risk prostate cancer patients.

Keywords: prostate cancer, 6DoF motion, dose reconstruction,

References:

[1] Martin NE, D'Amico AV. Progress and controversies: Radiation therapy for prostate cancer: Radiation for Prostate Cancer. CA A Cancer Journal for Clinicians. 2014;64:389-407.

[2] Ravkilde T, Skouboe S, Hansen R, Worm E, Poulsen PR. First online real ‐ time evaluation of motion ‐ induced 4D dose errors during radiotherapy delivery. Med Phys. 2018;45:3893-903.

[3] Poulsen PR, Cho B, Keall PJ. Real-time prostate trajectory estimation with a single imager in arc radiotherapy: a simulation study. Physics in Medicine and Biology. 2009;54:4019-35.