Breast Radiation Therapy Using a Breast Cup: Moving the Target, Not the Patient.

PURPOSE: To compare whole-breast radiation therapy dose distributions with and without the use of breast cups to reposition the breast itself. METHODS AND MATERIALS: A fitted plastic breast cup repositions the breast on the anterior chest wall, reducing the lateral fall and ptosis of the breast. Eighteen patients requiring breast cups were identified on an initial simulation computed tomography scan (without breast cup); subsequently, a second scan with the breast cup fitted was performed. An optimal treatment plan was then created on both scans with the differences in radiation dose to underlying organs compared. In vivo measurements were performed to assess any possible bolusing effect on skin dose owing to the breast cup. RESULTS: Breast cups significantly reduce dose to both lung and heart for all left-sided cases. All lung dose metrics decreased for all right-sided cases. Right-sided heart dose metrics did not significantly decrease with the use of breast cups; however, heart mean dose for these cases was all under 100 cGy. A 16% increase in skin surface dose was observed in an anthropomorphic phantom when using a breast cup. CONCLUSIONS: Use of the breast cup in breast radiation therapy decreases dose to underlying organs at risk and is cost-effective. It can be easily integrated with deep inspiration breath hold, intensity modulated radiation therapy, and volumetric-modulated arc therapy techniques. With use of the device, a supine patient position can be maintained, meaning nodal regions can be treated mono-isocentrically.

A comparison between radiation therapists and medical specialists in the use of kilovoltage cone-beam computed tomography scans for potential lung cancer radiotherapy target verification and adaptation.

Target volume matching using cone-beam computed tomography (CBCT) is the preferred treatment verification method for lung cancer in many centers. However, radiation therapists (RTs) are trained in bony matching and not soft tissue matching. The purpose of this study was to determine whether RTs were equivalent to radiation oncologists (ROs) and radiologists (RDs) in alignment of the treatment CBCT with the gross tumor volume (GTV) defined at planning and in delineating the GTV on the treatment CBCT, as may be necessary for adaptive radiotherapy. In this study, 10 RTs, 1 RO, and 1 RD performed a manual tumor alignment and correction of the planning GTV to a treatment CBCT to generate an isocenter correction distance for 15 patient data sets. Participants also contoured the GTV on the same data sets. The isocenter correction distance and the contoured GTVs from the RTs were compared with the RD and RO. The mean difference in isocenter correction distances was 0.40cm between the RO and RD, 0.51cm between the RTs, and RO and 0.42cm between the RTs and RD. The 95% CIs were smaller than the equivalence limit of 0.5cm, indicating that the RTs were equivalent to the RO and RD. For GTV delineation comparisons, the RTs were not found to be equivalent to the RD or RO. The alignment of the planning defined GTV and treatment CBCT using soft tissue matching by the RTs has been shown to be equivalent to those by the RO and RD. However, tumor delineation by the RTs on the treatment CBCT was not equivalent to that of the RO and RD. Thus, it may be appropriate for RTs to undertake soft tissue alignment based on CBCT; however, further investigation may be necessary before RTs undertake delineation for adaptive radiotherapy purposes.