Electromagnetic Navigation System for CT-Guided Biopsy of Small Lesions

OBJECTIVE. The purpose of this study was to evaluate an electromagnetic navigation system for CT-guided biopsy of small lesions.MATERIALS AND METHODS. Standardized CT anthropomorphic phantoms were biopsied by two attending radiologists. CT scans of the phantom and surface electromagnetic fiducial markers were imported into the memory of the 3D electromagnetic navigation system. Each radiologist assessed the accuracy of biopsy using electromagnetic navigation alone by targeting sets of nine lesions (size range, 8–14 mm; skin to target distance, 5.7–12.8 cm) under eight different conditions of detector field strength and orientation (n = 117). As a control, each radiologist also biopsied two sets of five targets using conventional CT-guided technique. Biopsy accuracy, number of needle passes, procedure time, and radiation dose were compared.RESULTS. Under optimal conditions (phantom perpendicular to the electromagnetic receiver at highest possible field strength), phantom accuracy to the center of the lesio...