Rx:52Gy/26fx to Pancreas and 46.8Gy to PTV

2012 AAMD / ROR Plan Challenge


2:38 VMAT treatment arc delivery time

Simple DVH Metrics

Name (ID): Z002442-ABD, AAPM (AAPM Z002442-ABD)
Plan or PlanSum ID: 4arcAID

Structure ID Structure Code Patient Structure DVH Objective Evaluator Variation Priority Met Achieved
PTV_5200   PTV_5200 V52.0Gy[%] >=95 93   Goal 96.46 %
PTV_5200   PTV_5200 V49.4Gy[%] >=99 97   Goal 100.00 %
PTV_5200   PTV_5200 D0.03cc[Gy] <=53 56   Variation 54.409 Gy
CTV_5200   CTV_5200 V52.0Gy[%] >=99 97   Goal 99.99 %
PTV4680-PTV5200   PTV4680-PTV5200 V46.8Gy[%] >=95 93   Variation 94.37 %
PTV4680-PTV5200   PTV4680-PTV5200 V44.66Gy[%] >=99 97   Goal 99.50 %
CORD   CORD D0.03cc[Gy] <45     Goal 32.780 Gy
RT KIDNEY   RT KIDNEY V18.0Gy[%] <=10 50   Variation 19.56 %
LT KIDNEY   LT KIDNEY V18.0Gy[%] <=0 30   Variation 0.81 %
BOWEL   BOWEL V45.0Gy[cc] <=175 250   Goal 142.95 cc
LIVER   LIVER Mean[Gy] <=5 10   Variation 5.437 Gy
STOMACH   STOMACH D25%[Gy] <=10 30   Variation 12.526 Gy
PERIPHERAL_RING   PERIPHERAL_RING V23Gy[cc] <=20 100   Goal 19.86 cc
Scorecard Metrics
Technical Plan Comments

The VMAT technique was chosen and 4 almost complete arcs were used.  Each arc used a different start and stop angle (offset by 1 degree) to stagger the available control points throughout each arc rotation.  Unique collimator rotations were selected per arc and ordered for fastest treatment delivery (330, 0, 30, 90).  Zero degree collimator arc rotations make sense on this machine due to the reduced interleaf leakage of the two-stage, stacked and staggered MLC design.  At first, VMAT would seem like the ideal technique to meet the challenging metric of no 50% of Rx dose (more than 3cm from the target anteriorly and 3cm from the skin surface elsewhere -- enforced by a “peripheral ring” metric in the scoring criteria).  However, all efforts to improve upon the static field IMRT plan (utilizing VMAT technique) failed and this VMAT plan scored lower than the IMRT attempt, took slightly longer to deliver and took longer to optimize.  From the CMD perspective the IMRT plan is the clear choice for this case.

Physician Comments

Both pancreas RT plans were acceptable. The IMRT plan is slightly better. In both cases, the OARs, specifically the bowel. The homogeneity requirements are pretty tight and a priority in this case. These are achieved with good sparing of bowel and kidneys.

Comparative Plan

3rd party software plan report


Dosimetric Scorecard


 DICOM patient export       


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