ESTRO meets Asia 2024 - Abstract Book

S384

RTT – Treatment planning, OAR and target definitions

ESTRO meets Asia 2024

15

Digital Poster

A Novel Technique for Planning and Treating Dupuytren's Disease with VMAT

Gerald B. Fogarty 1,2,3 , Yunfei Hu 1 , Aaron Pritchard 1

1 Gosford, Icon Cancer Centre, Gosford NSW, Australia. 2 Faculty of Science, University of Technology, Sydney NSW, Australia. 3 Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton VIC, Australia

Purpose/Objective:

Dupuytren’s Disease (DD) is a prevalent condition characterized by the contracture of the palmar aponeurosis (PA), a fibrous layer in the palm [1]. In the early stages of DD, radiotherapy (RT) is commonly employed, with orthovoltage [2] and megavoltage electron (MeV) therapy [3] as established modalities. Despite its potential for superior dose distribution and plan robustness, Volumetric Modulated Arc Therapy (VMAT) remains unexplored in the context of RT for DD. This study elucidates our innovative technique utilizing VMAT to effectively treat the entire PA in cases of DD.

Material/Methods:

Within the authors' department, DD is systematically addressed with VMAT, delivered by a Varian Halcyon linear accelerator featuring a 6MV flattening-filter-free (FFF) photon beam. This comprehensive study delineates the entire DD treatment process employing VMAT, encompassing prescription, simulation, contouring, treatment planning, quality assurance, and treatment delivery. Furthermore, a plan comparison between the 6MV FFF photon beam and the MeV beam is undertaken to elucidate potential dosimetric advantages associated with utilizing VMAT for DD treatment.

Results:

In the author's department, the standard prescription for DD treatment involves a regimen of 30 Gy delivered in 10 fractions. Plan comparisons conducted under this dosage paradigm reveal that, by using optimization structures such as skin, ring structures, and flash bolus, VMAT can provide a dosimetric distribution equivalent to, if not superior to, MeV therapy. Furthermore, in-vivo dosimetry validates the precision of surface dose calculations by the Treatment Planning System (TPS). Offline image reviews indicate that the treatment setup, facilitated by the use of Moldcare cushion and mask, is notably straightforward and robust.

Conclusion:

This study has described the authors' experience in treating DD using VMAT on a Varian Halcyon linac. The application of VMAT, together with appropriate optimization structures, patient immobilization devices, and pre treatment imaging verification capacity, has the potential to improve dose conformity, calculation accuracy, and setup reproducibility in the treatment of DD.

Keywords: Dupuytren Contracture, Fibromatosis, VMAT