Feasibility and potential advantages using VMAT in SRS metastasis treatments

Fecha de publicación: 25/02/2021 Fecha Ahead of Print: 25/02/2021

Autores de IIS La Fe

• María José Pérez Calatayud

  Autor

• Antonio Menéndez López

  Autor

• Francisco Javier Celada Álvarez

  Autor

• Antonio Conde Moreno

  Autor

• Maria Bernisz

  Autor

• Françoise Lliso Valverde

  Autor

• Vicente Carmona Meseguer

  Autor

• José Gimeno Olmos

  Autor

• Carlos Botella Asuncion

  Autor

• José Pérez Calatayud

  Autor

Grupos

• Investigación Clínica y Traslacional en Cáncer

  

  Leader

  José Gómez Codina

• Unidad Mixta de Investigación en Radiofísica e Instrumentación nuclear en medicina

  Leader

  Facundo Ballester Pallares

Abstract

Background: Utilization of stereotactic radiosurgery (SRS) for brain metastases (BM) has become the technique of choice as opposed to whole brain radiation therapy (WBRT). The aim of this work is to evaluate the feasibility and potential benefits in terms of normal tissue (NT) and dose escalation of volumetric modulated arc therapy (VMAT) in SRS metastasis treatment. A VMAT optimization procedure has therefore been developed for internal dose scaling which minimizes planner dependence. Materials and methods: Five patient-plans incorporating treatment with frame-based SRS with dynamic conformal arc technique (DA) were re-planned for VMAT. The lesions selected were between 4-6 cm(3). The same geometry used in the DA plans was maintained for the VMAT cases. A VMAT planning procedure was performed attempting to scale the dose in inner auxiliary volumes, and to explore the potential for dose scaling with this technique. Comparison of dose-volume histogram (DVH) parameters were obtained. Results: VMAT allows a superior NT sparing plus conformity and dose scaling using the auxiliary volumes. The VMAT results were significantly superior in NT sparing, improving both the V-10 and V-12 values in all cases, with a 2-3 cm(3) saving. In addition, VMAT improves the dose coverage D-95 by about 05 Gy. The objective of dose escalation was achieved with VMAT with an increment of the Dmean and the Dmedian of about 2 Gy. Conclusions: This work shows a benefit of VMAT in SRS treatment with significant NT sparing. AVMAT optimization procedure, based on auxiliary inner volumes, has been developed, enabling internal dose escalation.

Keywords

• SRS; VMAT; metastasis; clinical dosimetry; radiotherapy