Rx: 60Gy/3fx

2014 AAPM / ROR Plan Challenge

8:12 VMAT treatment arc delivery time

Simple DVH Metrics

Name (ID): AAPM2014 SBRT LUNG, (ROQS-24)
Plan or PlanSum ID: 4arcIDt4a

Structure ID Structure Code Patient Structure DVH Objective Evaluator Variation Priority Met Achieved
PTV   PTV V60.0Gy[%] >=95 90   Goal 96.50 %
PTV   PTV V54.0Gy[%] >=100 99   Goal 100.00 %
PTV   PTV D0.03cc[Gy] >=66.666 100   Goal 75.164 Gy
ITV   ITV V60.0Gy[%] >=100 99   Goal 100.00 %
2CM GRADIENT   2CM GRADIENT D0.03cc[Gy] <=30.1 35   Goal 27.776 Gy
LUNG_TOTAL   LUNG_TOTAL V20.0Gy[%] <=5 10   Goal 4.03 %
LUNG_R   LUNG_R V5.0Gy[%] <=1 5   Variation 1.79 %
SPINAL_CORD   SPINAL_CORD D0.03cc[Gy] <18     Goal 13.944 Gy
ESOPHAGUS   ESOPHAGUS D0.03cc[Gy] <=10 15   Goal 8.677 Gy
HEART   HEART D0.03cc[Gy] <=15 20   Variation 15.034 Gy
SKIN   SKIN D0.03cc[Gy] <=15 20   Goal 14.050 Gy
RIB   RIB D0.03cc[Gy] <=32 40   Variation 32.254 Gy
AIRWAY   AIRWAY D0.03cc[Gy] <=15 25   Variation 15.129 Gy
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 (315, 0, 45, 90).  Zero degree collimator arc rotations make sense on this machine due to the significantly reduced interleaf leakage of the two-stage stacked and staggered MLC design.  This VMAT SBRT lung plan was limited to a coplanar arc arrangement, which therefore limited comformality of the 50% Rx dose.  This plan challenge was designed with the assumption of a noncoplaner arrangement.  However, with a large portion the optimization cost focused on this metric, the 50% RX dose volume was still able to be controlled to a relativly reasonable volume and the plan scored above the mean score of plans submitted to this challenge.

Physician Comments

Simple early stage lung Ca treated with SBRT. An aggressive dose of 60 Gy in 3 fractions is used. All OARs are within reasonable limits. The conformality index is somewhat borderline, but the plan is clinically acceptable.

Comparative Plan Quality

3rd party software plan report


   Dosimetric ScoreCard


 DICOM  patient export    


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