Mechanically-Flexible Actively-(Location)-tracked Interstitial Brachytherapy Radiation Delivery Stylet

Value Proposition

• Unique Flexibility and Active Tracking – currently the only stylet in existence that offers both flexibility and real-time active tracking, enhancing precision and safety in radiation delivery.
• Versatile Clinical Applications – suitable for various clinical uses, including radiation oncology, interventional radiology, and interventional cardiology. 
• Unique Market Position – the technology occupies a unique niche in medical devices, as actively tracked needles are currently non-existent in interventional radiology and cardiology.

 Technology Description

• The disclosed technology describes an actively tracked, flexible brachytherapy needle designed to enhance the delivery of interstitial brachytherapy. This form of radiotherapy involves placing radioactive sources (seeds) directly into or near the tumor to deliver high doses of radiation.
• There are several important new attributes to the disclosed technology:
  • The concentric tube design, made of super-elastic nitinol, allows for large deflections within a small distance, ensuring safe use within the applicator.
  • The metallic device can accommodate various tracking sensors at the distal end, in addition to MR-Tracking micro-coils. Current validated examples include EM tracking and Fiber Bragg Grating (FBG) Tracking together with ULS, X-ray, CT, or PET imaging.
  • There exist both manual and motorized versions of the technology. The motorized version, which is able to both rotate and advance (insert) the tracked stylets using pneumatic or piezo electric motors, includes a set-up into which the stylet is inserted that holds the stylet’s handle and has motors for manipulating the stylet, as well as slip rings that allow for the smooth transfer of electrical signals when they pass through a rotating connection between the device handle and the metallic tracked stylet. In the motorized unit, via use of a beveled tip together with a controlled entry speed, it is possible to change the insertion direction and deflect the tip in a desired direction.
  • The active-tracking allows correcting the path of the stylet during insertion into the body, using a surgical workstation that shows the spontaneous location of the device, which is acquired at a high frame rate, on the background of an image-set that shows the relevant anatomy and/or pathology, such as one of a number of existing MRI or ULS inter-tissue contrasts. This feature allows correcting the path of the stylet either manually or using a motor, if the path deviates from the planned insertion path. In the motorized version, the rotation direction of the beveled tip and the speed of insertion are used to perform this operation, either with complete human activation or with various degrees of autonomous robotic operation. The attached workstation also computes and displays the stylet path projection, which connects its prior locations and the present location. Based on the projection, it is possible to perform real-time estimates of the dose which can be delivered from each stylet. The dosimetry calculation provide an estimate of the addition motion required of a stylet, as well as calculating the possible need for adding additional stylets along additional optimized paths in order to better meet the therapeutic needs.  

 Unmet Need

• Interstitial Brachytherapy (brachy) is a well-established method for delivering high doses of radiation directly to tumors using needle-shaped devices inserted through the skin, fat, and muscle tissue. However, current brachytherapy devices lack flexibility and provide limited information on probe positioning. Therefore, there is a significant need for new medical devices that offer enhanced flexibility, improved visualization, and precise probe positioning relative to the tumor. 
• Similar devices can be used in interventional radiology, interventional cardiology and interventional neurosurgery to perform accurate image-guided insertion of needles, biopsy devices, cannulas, etc.

 Stage of Development

• Multiple prototypes have been built and tested in simulator applicators, including the Elekta Venezia applicator, showing promising preliminary results.
• Patient protection modules have been constructed and installed between the stylets and the MRI scanner, so that use of the MR-Tracked system can be performed in a manner that is MRI-safe.
• Software for real-time tracking using the MR-Tracked versions has been developed that works on Siemens MRI scanners operating on multiple software versions. Real-time connectivity between the stylet and external workstations based on the Siemens Access-I protocol have been developed and tested in phantoms and patients.
• Quality assurance protocols for MR-Tracking have been developed and tested in phantoms and patients.
• Software that computes the stylet path and dosimetry in real-time has been developed. The stylet path works on an open source 3D Slicer and both the path and dosimetry work on an Elekta Oncentra workstation.
• 1.5 Tesla MR-Tracked prototypes have been used in treating cervical cancer patients at JHU under an approved IRB.
• Current efforts are focused on constructing multiple devices, including those that can be used at multiple MRI field strengths, for clinical use at JHU, MD Anderson and Medical College of Wisconsin Radiation Oncology departments to validate preliminary results. 

 Data Availability

• Data available upon request.

 Publication

N/A