Language Select
Varian Logo

VARIAN MEDICAL AFFAIRS

Engaging with clinicians around the world to exchange meaningful information and advance clinical research.

IMRT1A

Rx: 30Gy/10fx

 

1:05 AP PA 2 field treatment delivery time

Beams
DVH
Technical Plan Comments

Due to the unflattened nature of the 6MV beam, traditional “2D” treatment techniques cannot be employed on most normal sized targets.

The inverse planning optimizer can be employed to deliver a homogenous dose distribution to the target, which requires a target volume.  In this case the vertebra contours were drawn on just a few CT slices including the desired most superior and inferior slices and the rest of the CTV was created using interpolation.  Then a small uniform expansion was created to make a PTV subtracting a (3mm) margin from the skin surface.  Each plan was then optimized using only the PTV and Normal Tissue Objective (NTO).  Optimization constraints used were as follows:

AP PA: PTV 100%  30.3Gy p140; PTV 0% 35Gy p110; NTO man p100 DTB1.0cm SD105% ED60% FO.05

Alternatively, the irregular surface compensator tool can be used to create a homogeneous dose at depth.  This method would likely involve manual edits to the ideal fluence prior to plan approval thereby maintaining a completely forward planned workflow.

Physician Comments

40Gy is too hot for the heterogeneity of this plan.  I would favor more weighting on PA beam to decrease dose to the anterior structures which are not the target lesion.  Coverage of the target lesion is good.  I usually keep cord <35Gy and it appears that it may be >33Gy based on the isodose lines.
 

Links

Review 3rd party software generated full treatment plan report

PDF

                               

Download full DICOM CT, struct, plan and dose file        

ZIP        

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.

FOR EDUCATIONAL AND SCIENTIFIC EXCHANGE ONLY – NOT FOR SALES OR PROMOTIONAL USE.

 

  • Follow Us

Production of any of the material contained herein in any format or media without the express written permission of Varian Medical Systems is prohibited.

Varian Logo