Comparison of Methods for Computing a Target Point for Aspirations and Biopsies

Abstract

The aim of this study was to compare three methods for computing a target point for use in autonomous or semi-autonomous aspirations and biopsies. Given a 3D binary image of the object of interest, the procedures computed the target point. The following approaches were tested: the method #1 - center of mass, the method #2 - largest projection area + largest empty circle and the method #3 - largest empty circle + largest empty circle. Each procedure was tested on four cases obtained from Magnetic Resonance Imaging scans used to diagnose Baker’s cysts. The methods were analyzed and compared in terms of their safety and computation time. In terms of safety, the best results were obtained with the third procedure, which used the largest empty circle + largest empty circle combination. The second method - the largest projection area + largest empty circle - offered good compromise between safety and computation time. It can be used to estimate target points for medical tool path planning in aspiration or biopsy.