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


Simple DVH Metrics

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

Structure ID Structure Code Patient Structure DVH Objective Evaluator Variation Priority Met Achieved
PTV2   PTV60 V60.0Gy[%] >=95 90   Goal 95.07 %
PTV2   PTV60 V54.0Gy[%] >=99 97   Goal 99.79 %
PTV2   PTV60 D0.03cc[Gy] <=66     Goal 65.647 Gy
PTV1   PTV46 V46.0Gy[%] >=95 90   Goal 100.00 %
PTV1   PTV46 V41.4Gy[%] >=99 97   Goal 100.00 %
PTV1   PTV46 D0.03cc[Gy] <=66     Goal 65.647 Gy
Rt Lens   Rt Lens D0.03cc[Gy] <7     Goal 5.671 Gy
Lt Lens   Lt Lens D0.03cc[Gy] <7     Goal 5.572 Gy
Rt Eye   Rt Eye D0.03cc[Gy] <50     Goal 18.203 Gy
Lt Eye   Lt Eye D0.03cc[Gy] <50     Goal 12.231 Gy
Rt Optic Nerve   Rt Optic Nerve D0.03cc[Gy] <55     Goal 51.409 Gy
Lt Optic Nerve   Lt Optic Nerve D0.03cc[Gy] <55     Goal 33.903 Gy
Optic Chiasm   Optic Chiasm D0.03cc[Gy] <56     Goal 54.553 Gy
Brain Stem   Brain Stem D0.03cc[Gy] <60     Goal 59.264 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.


3rd party software plan report


    Dosimetric ScoreCard


DICOM patient export       


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