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Title: WE-G-17A-05: Real-Time Catheter Localization Using An Active MR Tracker for Interstitial Brachytherapy

Purpose: To develop a novel active MR-tracking system which can provide accurate and rapid localization of brachytherapy catheters, and assess its reliability and spatial accuracy in comparison to standard catheter digitization using MR images. Methods: An active MR tracker for brachytherapy was constructed by adding three printed-circuit micro-coils to the shaft of a commercial metallic stylet. A gel phantom with an embedded framework was built, into which fifteen 14-Gauge catheters were placed, following either with parallel or crossed paths. The tracker was inserted sequentially into each catheter, with MR-tracking running continuously. Tracking was also performed during the tracker's removal from each catheter. Catheter trajectories measured from the insertion and the removal procedures using the same micro-coil were compared, as well as trajectories obtained using different micro-coils. A 3D high-resolution MR image dataset of the phantom was acquired and imported into a treatment planning system (TPS) for catheter digitization. A comparison between MR-tracked positions and positions digitized from MR images by TPS was performed. Results: The MR tracking shows good consistency for varying catheter paths and for all micro-coils (mean difference ∼1.1 mm). The average distance between the MR-tracking trajectory and catheter digitization from the MR images was 1.1 mm. Ambiguitymore » in catheter assignment from images due to crossed paths was resolved by active tracking. When tracking was interleaved with imaging, real-time images were continuously acquired at the instantaneous tip positions and displayed on an external workstation. Conclusion: The active MR tracker may be used to provide an independent measurement of catheter location in the MR environment, potentially eliminating the need for subsequent CT. It may also be used to control realtime imaging of catheter placement. This will enable MR-based brachytherapy planning of interstitial implants without ionizing radiation, with the potential to enable dosimetric guidance of catheter placement. We gratefully acknowledge support from the American Heart Association SDG 10SDG2610139, NIH 1R21CA158987-01A1, U41-RR019703, and R21 CA 167800, as well as a BWH Department of Radiation Oncology post-doctoral fellowship support. Li Pan and Wesley Gilson are employees of Siemens Corporation, Corporate Technology. Ravi Seethamraju is an employee of Siemens Healthcare.« less
Authors:
; ; ;  [1] ;  [2] ; ;  [3] ; ;  [4] ;  [5]
  1. Dana Farber Cancer Institute / Brigham and Women's Hospital, Boston, MA (United States)
  2. (United States)
  3. Brigham and Women's Hospital, Boston, MA (United States)
  4. Siemens Corporation, Corporate Technology, Baltimore, MD (United States)
  5. Siemens Healthcare, Boston, MA (United States)
Publication Date:
OSTI Identifier:
22409762
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; ACCURACY; BRACHYTHERAPY; IONIZING RADIATIONS; NMR IMAGING; PARTICLE TRACKS; PHANTOMS; PLANNING