Dr.Le:Regarding bolus, the IMRT approach often uses several beams that are tangential, resulting in greater skin dose. At our institution, further skin bolus is used only if there is frank skin involvement by tumor. As before, it would be placed on the patient’s skin prior to the planning CT.
Dr. Eisbruch: I would say that the indications for skin bolus with IMRT probably would be similar to those with conventional therapy. In practice, if the PTV (planning target volume) is determined to extend to the surface, then the skin becomes a target and is planned to receive full-dose therapy. Notwithstanding the dosimetric uncertainties at the surface, I have not seen recurrences in the skin and we usually do not introduce bolus before planning.