ESTRO 2024 - Abstract Book

S4195

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

ESTRO 2024

Significant dose deterioration was observed in individual fractions, with mean ± SD values of CTV HI% of 7.1% ± 2.1%(Fig2, boxes). After averaging over 4-8 fractions, this improved to 3.9% ± 1.1%, across all patients (Fig2, blue dots). For comparison the planned HI was 3.3% ± 1.2% (Fig2, green stars). Minimal dose variation was observed between different CT scans (Fig2).

Conclusion:

The internal tumor motion was estimated and the actually delivered fraction dose was reconstructed for clinical PBS proton therapy treatments.

Inter-fractional anatomical changes had a minimal impact on the dose distribution. However, intra-fractional motion affected the fraction doses due to interplay effects, which were smeared out when averaged over 4-8 fractions.

Keywords: Respiratory gating, proton therapy, liver

References:

[1] Cheng JC, Wu JK, Lee PC, Liu HS, Jian JJ, Lin YM, Sung JL, Jan GJ. Biologic susceptibility of hepatocellular carcinoma patients treated with radiotherapy to radiation-induced liver disease. International Journal of Radiation Oncology* Biology* Physics. 2004 Dec 1;60(5):1502-9.

[2] Kobeissi JM, Hilal L, Simone 2nd CB, Lin H, Crane CH, Hajj C. Proton therapy in the management of hepatocellular carcinoma. Cancers. 2022 Jun 12;14(12):2900.