Premium
Poster — Thur Eve — 63: Dosimetric impact of breathing motion in lung SBRT: Dual vs single volumetric modulated arc therapy
Author(s) -
ElSherif O,
Xhaferllari I,
Johnson C,
Chen J,
Gaede S
Publication year - 2012
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4740171
Subject(s) - nuclear medicine , medicine , dosimetry , radiation therapy , lung cancer , dose volume histogram , arc (geometry) , lung , radiation treatment planning , radiology , mathematics , oncology , geometry
Volumetric modulated arc therapy (VMAT) is a time efficient treatment delivery platform capable of producing highly conformal dose distributions with a single 360° arc. However, additional arcs can be used to further improve the conformal dose distribution. For these reasons, VMAT is often used for stereotactic body radiation therapy (SBRT) in which the treatment deliveries are hypofractionated. The dosimetric impact of tumour motion, especially in lung SBRT where tumour motion is most significant and treatments are hypofractionated, has always been a clinical concern. Through the use of 4‐dimensional computed tomography (4D‐CT), 4D dose distributions can be calculated that account for dosimetric errors due to motion and temporal variation in lung density that are not accounted for in clinical treatment plans. The purpose of this study was to quantify the dosimetric differences that arise due to tumour motion and variations in lung density between single and dual VMAT SBRT treatment plans. Six patients previously treated for stage I/II non‐small‐cell lung cancer with SBRT were included in this retrospective study. 3D and 4D dose distributions were calculated for both single and dual arc plans for each of the six patients. Dose‐volume histogram metrics are reported for the target and critical structures. The results show significant differences (p ≤ 0.05) between the 3D and 4D dose distributions for the ratio of the prescription isodose volume to the primary target volume (PTV). This result was consistent for both single and dual arc VMAT plans.