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IMRT1

Rx: 46Gy/23fx Initial plan to PTV46 with a 14Gy/7fx sequential boost to PTV2 (60Gy total)

RTOG 0825

1:48 initial IMRT treatment field delivery time

 

Beams
DVH
Metrics

Name (ID): GBM Patient 4SKT, (GBM80876)
Plan or PlanSum ID: Plan Sum

Structure IDStructure CodePatient StructureDVH ObjectiveEvaluatorVariationPriorityMetAchieved
PTV2PTV60V60.0Gy[%]>=9590Goal95.07 %
PTV2PTV60V54.0Gy[%]>=9997Goal99.79 %
PTV2PTV60D0.03cc[Gy]<=66Goal65.647 Gy
PTV1PTV46V46.0Gy[%]>=9590Goal100.00 %
PTV1PTV46V41.4Gy[%]>=9997Goal100.00 %
PTV1PTV46D0.03cc[Gy]<=66Goal65.647 Gy
Rt LensRt LensD0.03cc[Gy]<7Goal5.671 Gy
Lt LensLt LensD0.03cc[Gy]<7Goal5.572 Gy
Rt EyeRt EyeD0.03cc[Gy]<50Goal18.203 Gy
Lt EyeLt EyeD0.03cc[Gy]<50Goal12.231 Gy
Rt Optic NerveRt Optic NerveD0.03cc[Gy]<55Goal51.409 Gy
Lt Optic NerveLt Optic NerveD0.03cc[Gy]<55Goal33.903 Gy
Optic ChiasmOptic ChiasmD0.03cc[Gy]<56Goal54.553 Gy
Brain StemBrain StemD0.03cc[Gy]<60Goal59.264 Gy
Technical Plan Comments

Brain GBM treated sequentially following RTOG 0825.  Initial seven (7) field IMRT plan created with custom gantry positions to mimic the flat edges on the PTV1 target shape on the transverse planes.  Also, consideration was given to place beam edges so that a sharp gradient could be achieved against the highest value OARs (brainstem, optic nerve).  Further plan quality improvements would have been achieved, if from a beam's eye view, unique collimator rotations were selected per field to match the general angle of the target volume.

For the sequential boost, due to the round nature of the boost volume, VMAT technique was chosen and 3 almost complete arcs were used.  All target constraints were assessed separately in the boost plan. 

A plan sum was created to evaluate organs at risk and all the constraints were eventually met.  The challenge was achieving target coverage goals and max target dose limit while not exceeding maximum dose allowed to the optic nerve, chiasm and brainstem.  To achieve all goals in the initial plan and boost plan, both plans had to be re-optimized after an evaluation of the plan sum.  Finally, plan normalization of each separate plan was adjusted until the plan sum was satisfactory.

Physician Comments

This large field GBM treatment with a low dose area and a sequential boost has all OARs within tight limits. Homogeneity is excellent. The optic nerve limits are on the higher side, but the achieved gradients are fine. This is a clinically acceptable plan.

Links

Review 3rd party software generated full treatment plan report

PDF

                              

Download full DICOM CT, struct, plan and dose file         

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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.

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