How do you define your partial breast volumes when doing partial breast irradiation?

I think this depends on technique (3D-CRT), motion management, and image guidance.

For standard 3DCRT APBI, you can use B39 volumes or IMPORT LOW. I rarely do this as these volumes are quite large.

However, if you are going to use motion management (4DCT, DIBH) you can create an ITV or limit your expa...