Optical Force Sensor With Enhanced Resolution for MRI Guided Biopsy

A novel fiber optic force sensor design with enhanced resolution through titanium coating is fabricated using Fabry-Pérot Interferometry (FPI) method and integrated into an 18 gauge MRI compatible biopsy needle, to be used in MRI guided interventional biopsy operations. The force sensor range and resolution are defined, and also needle insertion detection, deflection detection, tissue characterization and differentiation capabilities are tested via benchtop experiments. Overall system performance is tested via in vitro experiments under MRI using a commercial prostate phantom with representative leisons and it was shown that high resolution force sensing can help user to make sure that biopsy specimens are taken from the correct location. The fabricated sensor can measure forces up to 20 N with 0.1 N resolution and Ti coating enhances the sensor resolution to 0.03 N. Using biopsy needles with force measurement capability can improve the accuracy and safety of MRI guided minimally invasive biopsy procedures such as prostate biopsy. Biopsy needles incorporating high resolution force sensor can be used as a promising tool for cancer diagnosis thru stiffness detection of benign and malignant tissues instead of collecting biopsy specimens.