VMAT SX1

Name (ID): SBRT, PROSTATE (AAMD_RSS2016PS)
Plan or PlanSum ID: ETiSX1hID

For the Halcyon machine, with its 6X FFF energy which results in higher dose to the skin surface, VMAT proved to be the best technique for this plan.  The low dose at the skin’s surface needs to be spread out as much as possible due to the way the scoring metric was designed (penalty for any 10Gy in patient’s skin).  The remaining challenges came in achieving a high conformation number and carving the urethra and neurovascular bundles out of the PTV.  This VMAT SBRT prostate plan was probably held back from scoring higher due to the ratio of MLC leaf size versus extremely small abutting/overlapping OARs.  Using four (4) arcs, each with a unique collimator rotation, reduced the effect of the 1cm leaves and resulted in a plan that still scored above the median and average scores of the 420 participants in the 2016 AAMD RSS ProKnow Plan Study.  Plan quality would likely have been futher enhanced withl six (6) total arcs with unique colimator rotations rather than the four (4) arc employed in this plan.

This prostate SBRT plan shows nice dose gradients. Hot spots are successfully off the urethra. Bowel/rectum constraints are all met. This is a clinically acceptable plan.

_{Any reference to a "plan study" are simply what the organizers call each case and may not be a "study" in the FDA sense as they may not have been published in a peer reviewed journal.
Varian does not provide medical advice and these are illustrative examples only.
Leading plans by expert planner. Your results may vary.}