Dynamic conformal arcs for lung stereotactic body radiation therapy: a comparison with volumetric modulated arc therapy

TL;DR

This study compares dynamic conformal arc therapy to volumetric modulated arc therapy for lung SBRT, showing DCA as a simpler, effective alternative with comparable dosimetric quality, especially in cases with less complex tumor geometries.

Contribution

It demonstrates that dynamic conformal arc therapy, particularly segment-weight optimized DCA, can match VMAT's dosimetric quality for lung SBRT with reduced complexity.

Findings

DCA provides near-equivalent dosimetric quality to VMAT.

Segment-weight optimized DCA yields similar dose distributions to VMAT.

DCA is advantageous in reducing interplay errors from respiratory motion.

Abstract

This study evaluates dynamic conformal arc (DCA) therapy as an alternative to volumetric modulated arc therapy (VMAT) for stereotactic body radiation therapy (SBRT) of lung cancer. The rationale for DCA is lower geometric complexity and hence reduced risk for interplay errors induced by respiratory motion. Forward planned DCA and inverse planned DCA based on segment-weight optimization were compared to VMAT for single arc treatments of three lung patients. Analysis of dose-volume histograms and clinical goal fulfillment revealed that DCA can generate satisfactory and near equivalent dosimetric quality to VMAT, except for complex tumor geometries. Segment-weight optimized DCA provided spatial dose distributions qualitatively similar to those for VMAT. Our results show that DCA, and particularly segment-weight optimized DCA, is an attractive alternative to VMAT for lung SBRT treatments, where errors from intrafraction motion cannot be expected to average out over the course of the treatment.