Circumferential or sectored beam arrangements for stereotactic body radiation therapy (SBRT) of primary lung tumors: effect on target and normal-structure dose-volume metrics.

Med Dosim
Authors
Keywords
Abstract

To compare 2 beam arrangements, sectored (beam entry over ipsilateral hemithorax) vs circumferential (beam entry over both ipsilateral and contralateral lungs), for static-gantry intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) delivery techniques with respect to target and organs-at-risk (OAR) dose-volume metrics, as well as treatment delivery efficiency. Data from 60 consecutive patients treated using stereotactic body radiation therapy (SBRT) for primary non-small-cell lung cancer (NSCLC) formed the basis of this study. Four treatment plans were generated per data set: IMRT/VMAT plans using sectored (-s) and circumferential (-c) configurations. The prescribed dose (PD) was 60Gy in 5 fractions to 95% of the planning target volume (PTV) (maximum PTV dose ~ 150% PD) for a 6-MV photon beam. Plan conformality, R50 (ratio of volume circumscribed by the 50% isodose line and the PTV), and D2cm (Dmax at a distance ≥2cm beyond the PTV) were evaluated. For lungs, mean doses (mean lung dose [MLD]) and percent V30/V20/V10/V5Gy were assessed. Spinal cord and esophagus Dmax and D5/D50 were computed. Chest wall (CW) Dmax and absolute V30/V20/V10/V5Gy were reported. Sectored SBRT planning resulted in significant decrease in contralateral MLD and V10/V5Gy, as well as contralateral CW Dmax and V10/V5Gy (all p

Year of Publication
2013
Journal
Med Dosim
Volume
38
Issue
4
Pages
407-12
Date Published
2013 Winter
ISSN
1873-4022
URL
DOI
10.1016/j.meddos.2013.05.002
PubMed ID
23810414
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