IMRT SX1

Due to the unflattened nature of the 6MV beam, traditional “2D” treatment techniques cannot be employed on most normal sized targets (small targets could be treated with minimal beam modulation (aka "Field in Field)).  The inverse planning optimizer or irregular surface compensator was employed to deliver a homogenous dose distribution to the target.  In this case, the glottic larynx was contoured and a non-uniform margin was used to generate a PTV which included cropping the skin-03mm.   The PTV was used in the optimizer and simple optimization objectives were created as follows:

PTV: 100%  50.2Gy p140; 0% 51.2Gy p110;

Body: 0% 52Gy p200

NTO: auto p50

Finally, after the <1min optimization, the skin flash tool was employed on both beams to create 2-3cm of fluence extension into air anterior to the patient’s larynx.

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.

This is a simple glottis case. The plan is pretty homogeneous. Coverage is adequate. No significant hotspots. This is an acceptable plan.

_{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.}