IMRT SX1

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 or the irregular surface compensator has to be employed to deliver a homogenous dose distribution to the target.  In this case AP/PA beams were placed visually on screen using the beams eye view to create a tangent style technique encompassing the target which was drawn to the skin surface with a uniform depth of 4mm.  Once verifying the isocenter was placed inside the tissue to be treated, and a 5mm bolus was created over the target and linked to the plan.  Then, the inverse planning optimizer was started and simple optimization objectives were created as follows:

PTV: 100%  55.3Gy p140; 0% 56.3Gy p110;

Body: 0% 57Gy p250

NTO: auto p50

Finally, after optimization the skin flash tool was employed on both beams to create 2-3cm of fluence extension into air laterally from the patient’s skin surface.

If a forward planed workflow is the preference, the irregular surface compensator tool can be used to create a homogeneous dose at depth.  Then manual edits to the ideal fluence can be emplyoyed, as needed,  to achive desired result.

_{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.}