Design and Experimental Setup of a Robotic Medical Instrument for Brachytherapy in Non-Resectable Liver Tumors

This paper presents a study regarding the design and the experimental setup of a medical robotic system for brachytherapy using tribology analysis. The robotic system is composed of a collaborative robotic arm and a multi-needle brachytherapy instrument controlled using a unified control system embedding a haptic device and force-feedback. This work is oriented towards identifying the technical characteristics of the system components to determine the accuracy of the procedure, as well as using different scenarios for needle insertion in ex vivo porcine liver tissue in order to determine the forces required for insertion and extraction of the needle and the friction coefficient that accompanies the previously mentioned forces. Subsequent to the computation of the friction forces, the normal forces and the wear during the needle insertion are determined with the scope of predicting the lifecycle of some components of the medical device.

Surgical Navigation System for Low-Dose-Rate Brachytherapy Based on Mixed Reality

This article presents a personalized mixed reality (MR) surgical assistance system for brachytherapy. Using a novel, modified multi-information fusion method, the fusion of virtual organs and a preoperative plan for an actual patient and the real-time tracking of surgical tools were achieved. Using the quaternion-based iterative closest point (QICP) algorithm and a hand-eye calibration method, the preoperative plan can be fused into individual patients. Using the electromagnetic (EM) tracker, users can track the surgery tools in real time, without multiple CT scans, and doctors can immediately perform the surgery. We performed a series of experiments, including phantom and animal experiments, to test the accuracy and efficiency of the system. In the phantom experiment, the average needle location error was 0.957 mm. Based on the results of animal experiments, the needle insertion error was 2.416 mm. All experimental results indicated that the procedure could be applied in further clinical studies.

Design and validation of a surgical navigation system for brachytherapy based on mixed reality

PURPOSE

An accurate position of the needle is vitally important in low-dose-rate seed implantation brachytherapy. Our paper aims to implement a mixed reality navigation system to assist with the placement of the I¹²⁵ seed implantation thoracoabdominal tumor brachytherapy needle and to validate the accuracy and quality of this type of method.

METHODS

With the surgical navigation system, based on mixed reality through a novel modified multi-information fusion method, the fusion of virtual organs and a preoperative plan for a real patient and the tracking of surgical tools in real time were achieved. Personalized image recognition and pose estimation were used to track needle punctures in real time and to perform registration processes. After a one-time registration with a hexagonal prism tracker that used an iterative closest point algorithm, all information, including medical images and volume renderings of organs, needles, and seeds, was precisely merged with the patient. Doctors were able to observe the tumor target and to visualize the preoperative plan. This system was validated in both phantom and animal experiments. The accuracy of this system was validated by calculating the positional and rotational error of each needle insertion. The accuracy of implantation of each seed was determined in an animal experiment to test the accuracy in low-dose-rate brachytherapy. The efficiency of this system was also validated through time consumption assessments.

RESULTS

In the phantom experiment, the average error of the needle locations was 0.664 mm and the angle error was 4.74°, average time consumption was 16.1 min with six needles inserted. Based on the results of the animal experiment, the accuracy of the needle insertion was 1.617 mm, while the angle error was 5.574° and the average error of the seed positions was 1.925 mm.

CONCLUSIONS

This paper describes the design and experimental validation of a novel surgical navigation system based on mixed reality for I¹²⁵ seed brachytherapy for thoracoabdominal tumors. This system was validated through a series of experiments, including phantom experiments and animal experiments. Compared with the traditional image-guided system, the procedure presented here is convenient, displays clinically acceptable accuracy and reduces the number of CT scans, allowing doctors to perform surgery based on a visualized plan. All the experimental results indicated that the procedure is ready to be applied in further clinical studies.