Room: Track 4
Purpose: Targeting small, breast lesions with high accuracy is critical for early stage diagnosis, treatment planning, and improving patient prognosis. Current anatomical image-guided biopsy methods are limited in sensitivity and targeting accuracy, especially for women with dense breasts. We propose a positron emission mammography (PEM) ultrasound (US)-guided biopsy workflow, to combine functional-based target localization with real-time anatomical detail to improve guidance for tumour sampling. This work presents the development and validation a mechatronic needle-tracking system for PEM and US-guided breast biopsy.
Methods: A mechatronic needle-tracking system was developed to operate with an advanced PEM and US imaging system. The system features a manually operated, mechatronic guidance arm with ability to access the breast between PEM detector plates. The end-effector is a biopsy device containing an integrated US transducer and biopsy gun with its needle focused on a remote-center-of-motion. Custom software modules were developed to track, display, and guide the biopsy device. Guiding the needle to calibration fiducials on a simulated PEM detector plate registered the coordinate systems using landmark-based registration. Validation was performed with fiducials at various locations within the targeting volume of a breast between detector plates, simulating PEM detected lesions. Fiducial Registration Error (FRE) and Target Registration Error (TRE) were quantified to evaluate accuracy. Within 95% confidence intervals, 3D principal component analysis assessed directional trends.
Results: Registration and validation resulted in an FRE of 0.23±0.20mm (N=8) and TRE of 0.70±0.20mm (N=72). A 3D prediction ellipsoid, centered on the mean targeting error, demonstrates the ability to successfully target within a spherical region <2mm in diameter with 95% confidence.
Conclusions: We demonstrate accurate, dynamic needle-tracking with sub-millimeter guidance error within the 3D targeting region of a breast between simulated PEM detector plates. Our mechatronic system demonstrates potential to improve targeting accuracy as a novel means toward image-guided breast biopsy.
Funding Support, Disclosures, and Conflict of Interest: Funding supported by the Ontario Institute for Cancer Research (OICR) and the Canadian Institutes of Health Research (CIHR). C Park is supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, and the Translational Breast Cancer Research Unit funded by the Breast Cancer Society of Canada.