MR Thermometry-Guided Robotic System for Precise Applicator Insertion in Interstitial Thermal Therapy

Precise placement of thermal applicators is crucial for effective tissue ablation in Interstitial Thermal Therapy (ITT). Accurately localizing these applicators, which are often encapsulated within needles, poses a challenge because the thermal applicators are usually indistinct from the needles in MR (Magnetic Resonance) images. This difficulty necessitates a common clinical strategy of using low-power activation with MR Thermometry to confirm the position of the heating center. We developed and validated an MR thermometry-guided robotic system to enhance applicator insertion accuracy in ITT. The system integrates an MR-conditional robot, iterative MR scanning plane refinement, and live thermal map feedback to localize the heating applicator and improve insertion precision. Automated localization is achieved within 30 seconds of scanning, with the system autonomously adjusting applicator positioning based on localization results. Experimental validation demonstrated substantial improvements in targeting accuracy, achieving a 0.8 mm average and 2 mm maximum error after insertion compensation. The thermal effects were negligible, with the 6-degree rise isotherm limited to a 3.4 mm radius. This system enhances ITT by improving the precision of thermal energy delivery, minimizing damage to healthy tissues, and offering the potential to streamline clinical adoption while providing safer and more effective treatment options.