Medical Navigation System Using Shape-Sensing Fiber
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Solution Overview
Problem
Conventional navigation systems for medical procedures, such as biopsies, face challenges in accurately guiding medical devices through complex and dynamic environments like the lungs due to limitations in tracking technologies and exposure to radiation.
Innovation Solution
A medical navigation system employing optical shape-sensing fiber technology to determine the position and orientation of a shape-sensing device within a flexible medical instrument, generating real-time 3D volumes and calculating errors to guide the device through natural and off-road paths within organs, minimizing radiation exposure and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional tracking technologies (EM, X-ray, CT) are used to determine device position, then real-time tracking capability is achieved, but measurement precision deteriorates due to respiratory and cardiac motion causing large deformations
Solution Approach 1:
The patent divides the tracking function into two parts: a single-point tracker (EM or optical) provides real-time position data, while a separate shape-sensing fiber embedded in the device shaft measures the actual 3D configuration of the device. By segmenting the tracking system this way, the patent achieves both real-time tracking and high precision, as the shape-sensing fiber is insensitive to respiratory and cardiac motion that affect single-point tracking.
Solution Approach 2:
The shape-sensing fiber acts as an intermediary between the device shaft and the tracking system. Instead of directly tracking the device tip position (which is affected by motion), the fiber measures the shaft's configuration as an intermediate parameter. This intermediary measurement allows reconstruction of the device pose with high precision even when the tip moves due to respiratory and cardiac motion.
2Loss of information
If X-ray and CT tracking systems are used to visualize device position, then imaging capability is improved, but harmful radiation exposure increases for patients and clinicians
Solution Approach 1:
The patent replaces the mechanical/radiation-based tracking systems (X-ray, CT) with an optical sensing system. The shape-sensing fiber uses optical principles (light transmission through the fiber) to measure device configuration, eliminating the need for ionizing radiation. This substitution maintains imaging capability while removing the harmful radiation exposure to patients and clinicians.
3Ease of operation
If conventional bronchoscopes are used for peripheral lung lesion biopsy, then access to airways is achieved, but device size becomes too large to fit through small airways
Solution Approach 1:
The patent employs a flexible device shaft with an embedded shape-sensing fiber that can be made very thin to fit through small peripheral airways. The flexible shaft, rather than a rigid conventional bronchoscope, can navigate tortuous airway paths while the embedded fiber maintains shape measurement capability. This allows access to peripheral lung lesions through airways too small for conventional bronchoscopes.
4Device complexity
If single-point-based tracking technologies are used to locate device tip, then tracking simplicity is maintained, but accuracy deteriorates due to large deformations from respiratory and cardiac motion
Solution Approach 1:
The patent transitions from tracking in one dimension (tip position coordinates) to tracking in multiple dimensions by adding shape-sensing fiber measurements. The fiber provides distributed shape data along the device shaft, adding dimensional information about the device configuration. This multi-dimensional approach allows accurate reconstruction of tip position even when the shaft deforms due to respiratory and cardiac motion, maintaining simplicity while improving precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy and safety of medical procedures by providing real-time guidance through complex tissues while reducing patient and clinician exposure to radiation.
Implementation Method 1
A shape-sensing device (SSD) which senses position and orientation along its length and generates corresponding SSD information (SSDI)
Data Source
AI summary
A medical navigation system including a controller configured to: generate a three-dimensional (3D) volume based upon acquired image information of a region of interest (ROI), determine a reference path (RP) to an object-of-interest (OOI) situated within the ROI, the RP defining an on-road path (ONP) through at least one natural pathway of an organ subject to cyclical motion and an adjacent off-road path (ORP) through tissue of the organ leading to the OOI, and an exit point situated between the ONP and the ORP, query an SSD within the at least one natural pathway to obtain SSDI, determine a shape and a pose of one or more portions of the SSD in accordance with the SSDI, calculate an error between the RP and the determined shape and pose of the SSD, and/or determine when or where to exit a wall of the natural pathway and begin the ORP based upon the calculated error.