A dosimetric comparison between volumetric-modulated arc therapy and dynamic conformal arc therapy in SBRT

Sotirios Stathakis, Ganesh Narayanasamy, Anna Laura Licon, Pamela Myers, Ying Li, Richard Crownover, Niko Papanikolaou

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Purpose: The purpose of this study was to investigate the dosimetric equivalency of dynamic conformal arc therapy (DCAT) against volumetric modulated arc therapy (VMAT) plans in stereotactic body radiation therapy (SBRT) of lung and liver lesions and to examine if efficiency can be increased. Methods: Nineteen patients previously treated for lung and liver cancer lesions with SBRT were included. Organs at risk (OAR) and targets were contoured by a single radiation oncologist. All plans were optimized by the same dosimetrist using ELEKTA Monaco treatment planning system version 5.0 for 6MV flattening filter free (FFF) photon beam in a VersaHD (ELEKTA, Crawley, UK). A VMAT and DCAT plan was optimized using the same objectives using coplanar arcs of 225° arc span. Results: All plans have achieved the target and OAR planning objectives. The target dose conformity was comparable (mean VMAT PTVr=1.3 and DCAT PTVr=1.4), and the low dose spillage were similar (mean VMAT R50=4.5 and DCAT R50=4.6). However, monitor units (MU) for DCAT plans were lower by 2.5 times on average than VMAT plans. It was observed that in 75% of cases where OARs overlapped with the PTV, maximum doses to OAR were higher in VMAT than DCAT plans, but the difference was not significant. Patient specific quality assurance (QA) plans were measured using the Scandidos Delta4 phantom and gamma analysis performed using 2mm distance to agreement (DTA) and 2% dose difference yielded more than 95% passing rates on both VMAT and DCAT plans. Conclusions: DCAT delivery for lung and liver SBRT is a dosimetrically equivalent and an efficient alternative to VMAT plans.

Original languageEnglish (US)
Pages (from-to)838-843
Number of pages6
JournalJournal of B.U.ON.
Issue number2
StatePublished - Mar 2019


  • DCAT
  • Lower MUs
  • OAR sparing
  • SBRT
  • VMAT

ASJC Scopus subject areas

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


Dive into the research topics of 'A dosimetric comparison between volumetric-modulated arc therapy and dynamic conformal arc therapy in SBRT'. Together they form a unique fingerprint.

Cite this