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Session Item

Saturday
May 08
14:15 - 15:30
Brachytherapy physics 2030 – Adaptive dose delivery and planning
In this session the latest developments and advancements on adaptive dose planning and delivery are discussed. The first presentation will highlight the potential and limitations of image registration in treatment planning, in particular for gynaecological brachytherapy, with special attention for the challenges associated with deformable image registration in contouring and dose accumulation. Next, the role of automation in the treatment planning and delivery process will be handled. Automation is increasingly finding its way into clinical practice in terms of applicator digitization, plan optimization, quality assurance and plan documentation. This will affect the role of physicists in treatment planning as well as the interaction with physicians, coming with a change in practice. Finally, an introduction will be given on artificial intelligence, machine learning and big data, and the potential role it can directly play in brachytherapy applications such as contouring and dosimetric planning.
Symposium
00:00 - 00:00
Treatment Planning Study for STereotactic Arrhythmia Radioablation (STAR) of Ventricular Tachycardia
PO-1489

Abstract

Treatment Planning Study for STereotactic Arrhythmia Radioablation (STAR) of Ventricular Tachycardia
Authors: Bonaparte|, Ilaria(1);Gregucci|, Fabiana(1);SURGO|, Alessia(1)*[surgo.alessia@gmail.com];Carbonara|, Roberta(1);Vitulano|, Nicola(2);Quadrini|, Federico(2);Grimaldi|, Massimo(2);Di Monaco|, Antonio(2);Fiorentino|, Alba(1);
(1)Miulli General Regional Hospital, Radiation Oncology, Acquaviva delle Fonti-Bari, Italy;(2)Miulli General Regional Hospital, Cardiology, Acquaviva delle Fonti-Bari, Italy;
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Purpose or Objective

STereotactic Arrhythmia Radioablation (STAR) was recently introduced for ventricular tachycardia (VT). With precise high-dose of radiation to a well define target, STAR could become more than an option in the next future. The first STAR treatment based on linear accelerator (Linac) in our department was delivered in September 2019, thus the present analysis reported the differences of treatment plans in terms of efficiency and efficacy.

Material and Methods

The anatomy and target volume of the first treated patient were used for this study. A dose of 25 Gy in one fraction was prescribed to the planning target volume (PTV). Treatment plans were generated on Varian TrueBeamTM and 6-MV flattening filter free (FFF) beam (Eclipse planning system, V.15). Firstly, several plans (Plans #1-4) prescribed to the 75.0% isidose line were generated and compared to chose the best one. The 4 plans differed in terms of number, length arcs and couch rotations. Secondly, from the best plan, other treatment plans were generated: one with 10FFF beams, and the other 3 plans were optimized to have a prescription isodose line between 63% to 75% (corresponding to dose heterogeneity of 150% and 130%). All plans were optimized to be conformal to the PTV and meet dose constraints on the organs at risk (AAPM Task Group 101). The plans were compared by prescription isodose line, plan conformity index, as well as dose to the healthy heart. To assess the delivery efficiency, planned monitor units (MU) and estimated treatment time were evaluated.

Results

For Plans #1-4, the PTV coverage ranged from 96- to 98.5%; with a mean cardiac dose from 4.9-5.2Gy; MUs ranged from 7300 to 8541 for an beam-delivery-time (BDT) of 5.5, 5; 6 and 7 minutes, respectively. For the second part of the analysis, from the best geometrical conformation Plan, other 4 plans (Plans #5-8) with 10FFF approach and plans prescribed to 70, 72 and 63 isodose lines, were optimized. The PTV coverage ranged from 96- to 98.6%; with a mean cardiac dose from 4.9-5.2Gy, and MU from 6269 to 9394. CI ranged from 0.96-0.98. The BDT was ranged from 3 (for plans with 10MV-FFF beams) to 7 minutes.

Conclusion

Clinically acceptable plans were generated with Linac-based STAR approach. All plans were considerably more efficient in terms of MU and delivery time. The 10FFF approach was faster but it was not considered for all patients, due to the presence of cardiac device such as ICD.