VMAT breast leakage

[GRES Anthony]

Hi everybody,

 

We just begin VMAT techniques for breast cancer and I have some questions.

We try to make a virtual bolus (density=0.12) of 1cm for first calculation to make an virtual leak (for uncertainties) then we optimize on this volume minus 5mm.

Could you tell me if you use this bolus or not, and if so with what density and what size?

After what we compute again beam without vitual bolus (and without optimisation only computation) for check if result on patient is ok.

If you have some hot spot after removing this bolus do you have some solutions to remove this hot spots?

We use the bolus only for breast but we ask ourselvelves questions : do you think that we have to create virtual bolus for axillary volume, for internal mammary chain, supraclavicular?

Also we’ve saw that it’s difficult to obtain good coverage of PTV internal mammary chain that’s why we check coverage of this organ minus air.

Do you have any idea or experience on this case?

We use Pinnacle Evolution 16.4.2.

 

Many thanks

 

Anthony