Tumor Bed Delineation for Partial Breast and Breast Boost Radiotherapy Planned in the Prone Position: What Does MRI Add to X-ray CT Localization of Titanium Clips Placed in the Excision Cavity Wall?

Addition of MR to CT/clip data generated TB volumes that were discordant with those based on CT/clips alone. However, clinically satisfactory coverage of CTVMRCT by CTVCT-based tangential PBI fields provides support for CT/clip-based TB delineation remaining the method of choice for PBI/breast boost radiotherapy planned using tangential fields.