Dual Modality Surgical Guidance for Non-palpable Breast Lesions

Abstract

Currently, the majority of lumpectomy and excisional biopsy procedures are performed using the wire localization (WL) technique; however, this technique suffers from several drawbacks including inaccuracy in placement of the wire, possible displacement of the wire prior to surgery, and ambiguity of the lesion’s location along the wire. We propose dual modality surgical guidance (DMSG) as a means to overcome many of the problems associated with WL. The approach uses a dual modality (digital mammography and breast scintigraphy) breast imaging system developed in our lab to place a small radioactive marker (a radiomarker), directly into the lesion. Here we present the results of measurements of the localization and injection accuracy of our system. The localization accuracy, evaluated by determining the difference between the known and measured inter-well separations, were within 0.76 mm (standard deviation of 0.46 mm) of the true distances for x-ray imaging and within 0.66 mm (standard deviation of 0.43) for gamma imaging. Our maximum error in injection accuracy in any of the three Cartesian coordinates was 1.8 mm. On average, the errors were 0.6, 0.4, and 0.9 mm for x, y, and z respectively. The results of these phantom tests provide encouragement that our upright digital mammography unit can accurately a) locate a lesion in three dimensions, b) inject a radiomarker into the lesion, and c) assess the offset between the lesion and radiomarker centers.