ESTRO 2024 - Abstract Book

S3456

Physics - Dose calculation algorithms

ESTRO 2024

An algorithm was designed to aid the decision-making process at CT-simulation on which motion-management strategy was the most appropriate for the patient (figure 1). The pre-treatment Radiation Therapist assesses the patient-based on their ability to breath-hold and selects the relevant scanning protocol and planning technique required for the liver SABR treatments. Reproducibility of liver position using breath-hold is highly consistent is the favoured approach if the patient can successfully achieve a suitable breath-hold. Image guidance is of paramount importance and a combination of CBCT, marker match and fiducial tracking are utilised to assess for inter and intrafraction motion. The use of implanted fiducial markers for live tracking of the liver target in combination with breath-hold may be associated with trends for improved local control. (1) Align RT surface-guidance is also used passively during delivery.

Conclusion:

Liver SABR is feasible using the workflow we have identified. A one size fits all solution is suboptimal due to patient and tumour-specific issues. This scenario-based algorithm encompassing several motion management and IGRT strategies provides a framework for accurate delivery while minimising the treated volume. We believe the success of motion-management strategies for liver SABR delivery is dependent on the appropriate technique and strategy selected at the pre-treatment stage.

Keywords: Liver SABR, motion management

References:

1. Mathew AS, Atenafu EG, Owen D, Maurino C, Brade A, Brierley J, et al. Long term outcomes of stereotactic body radiation therapy for hepatocellular carcinoma without macrovascular invasion. European Journal of Cancer. 2020;134:41-51.