HI Shahin,

There are have been a couple of papers on this topic published.  

Evaluation of Elekta VMAT for Stereotactic Body Radiotherapy (SBRT): Comparison with Helical TomoTherapy (HT), BrainLAB Dynamic Conformal Arc Therapy (DCAT), and Fixed Field Therapy

International Journal of Radiation Oncology*Biology*Physics, Volume 78, Issue 3, Supplement, 1 November 2010, Pages S835-S836

X. Qi, A. Hu, W. Dzingle, K. Stuhr, H. Rice, Q. Diot, F. Newman

A planning comparison of 3-dimensional conformal multiple static field, conformal arc, and volumetric modulated arc therapy for the delivery of stereotactic body radiotherapy for early stage lung cancerOriginal Research Article

Medical Dosimetry, Volume 40, Issue 4, Winter 2015, Pages 347-351

Mike Dickey, Wilson Roa, Suzanne Drodge, Sunita Ghosh, Brad Murray, Rufus Scrimger, Zsolt Gabos

Implementation and evaluation of modified dynamic conformal arc (MDCA) technique for lung SBRT patients following RTOG protocolsOriginal Research Article

Medical Dosimetry, Volume 38, Issue 3, Autumn 2013, Pages 287-290

Chengyu Shi, Adam Tazi, Deborah Xiangdong Fang, Christopher Iannuzzi

 I am currently completing a Masters by research degree on treatment planning for lung SBRT and have found that VMAT is a suitable choice, especially for those tumours close to OAR or overlapping the chest wall.  I haven't had too much experience with DCAT but my understanding is that arc length will be similar to that of VMAT so the low dose wash will be similar, but then high and intermediate dose wash will be a lot steeper with VMAT.  VMAT is always going to look better dosimetrically on paper as it is inversely planned, however the lengthier treatment times and risk of interplay effect are eliminated with DCAT. More than happy to help you with any lung SBRT related topics.

Hi Rhys,

Thanks for your reply. I am currently supervising an MSc student whose work is about dosimetric comparison between DCAT and VMAT lung SBRT. His preliminary plans seem to show slight advantage of DCAT for low dose splashing into the lung but that seems to be more so for centrally located tumors.

Hello Shahin,

   My Msc thesis was also about comparing DCAT and VMAT techniques according to RTOG 0915 protocol.  I worked with 20 patients and I observed V20Gy lung percentage. According to my data avarage V20Gy for VMAT %3.88 for DCAT %4.02 also VMAT has statistical significance  to DCAT. (p=0,001).

   On the other hand I agree with Mr. Fitzgeralds undertsandings. Treatment time depends on MU and DCAT has way  more lower MU than  VMAT.  DCAT reduceses interplay effect but VMAT has sharp high and intermediate dose gradients.

Best regards