Preoperative radioactive seed localization of nonpalpable soft tissue masses: an established localization technique with a new application.

OBJECTIVE: To describe the technique of iodine125 (I125 ) seed deployment into nonpalpable soft tissue masses under direct ultrasound (US) or CT guidance for intraoperative localization.

MATERIALS AND METHODS: Patients considered candidates for radioactive seed localization (RSL) based on advanced imaging findings underwent an ultrasound examination of the area of concern to verify sonographic visualization of the targeted mass. If the mass was not visible sonographically, CT was used for guidance. Patients were scheduled for surgery 1-4 days after seed implantation. Intraoperative frozen section pathological analysis was performed on all patients. Operative time, specimen volume, intraoperative margin status, and final margin status were recorded. Following the surgery, patients and surgeons completed satisfaction surveys.

RESULTS: Ten patients underwent seed placement between 1 and 4 days prior to surgery. All patients had successful surgical resection of the targeted mass with removal of all implanted radioactive seed(s). There was no seed migration. Intraoperative frozen-section margins were negative (>2 mm) in 6/10 patients. Final surgical margins were negative in 9/10 patients. The patient with a positive margin at final pathology did not undergo further resection due to the benign nature of the mass. Patient and surgeon satisfaction survey results were highly positive. All four surgeons reported a strong preference for seed localization over wire localization.

CONCLUSIONS: RSL is an effective, reliable, and safe technique for preoperative localization of nonpalpable soft tissue masses and yields high patient and surgeon satisfaction.