Imaging findings after breast brachytherapy.
OBJECTIVE: The purpose of this study was to determine whether there are imaging changes specific to partial breast radiation therapy with interstitial catheters or a single balloon. MATERIALS AND METHODS: The records of 43 of 83 patients treated with partial breast irradiation at our institution from June 1996 to October 2003 were retrospectively reviewed. The images of 27 patients who had received radiation by interstitial catheters and 16 who had received radiation by a single balloon were reviewed. Patients were examined for the presence of skin thickening, diffuse and focal increased density, mass, lucency, and calcifications. Fifteen initial sonograms were ordered to evaluate pain or focal findings on mammograms. In addition, two patients underwent one and one patient underwent three follow-up sonographic examinations. RESULTS: Mild to moderate skin thickening was present in 26 (60%) and no skin thickening in 17 (40%) of the 43 patients. Forty-one (95%) of the 43 patients had focal increased density. Diffuse increased density was seen in only one (2%) of the patients. There was no change in overall density in 2 (5%) of the patients. Fifteen (35%) of the 43 patients had mass or seroma at the first follow-up examination. Central lucency was present in 35 (81%) of 43 patients on at least one follow-up study. Calcification was present in 8 (19%) of 43 cases. CONCLUSION: Imaging findings after breast brachytherapy include the spectrum of findings seen with external beam radiation but are more focal. The focal findings may be alarming both clinically and radiographically, but biopsy can be avoided in most instances if information from the history is correlated with findings from continued follow-up of the patient's case.