ext beam irradiation for porsate a and femurs as OAR

[RayAb]

I like to use a technique whereby the lateral fields go through the Head of femurs so as to absolutely reduce the DVH given to the rectal circumference. This allows a very low rectal toxicity - which seems lower than that conventionally reported with the usual OAR constraint of for the rectum of V 30 < 70Gy.
However, it will increase the dose to the femoral heads. I have not yet seen a femoral neck fracture in these patients (unlike the Gynaes). However, I may have been lucky. I have seen people refer to a V50 < 50 Gy fo r the femoral neck. Are there any comments on femur neck toxicity in patients after prostate irradiation and the use of other dose constraints on the DVH.
Raymond