@article {Brastianos2017a, title = {Electromagnetic Reconstruction of Catheter Paths in Mult-Catheter Interstitial Brachytherapy: A Phantom Model.}, year = {In Press}, author = {Harry Brastianos and Thomas Vaughan and Andras Lasso and Mary Westerland and James Gooding and Gabor Fichtinger and Conrad Falkson} } @article {Gauvin2019, title = {Real-time electromagnetic navigation for breast-conserving surgery using NaviKnife technology: A matched case-control study}, journal = {The Breast Journal}, volume = {26}, number = {3}, year = {2020}, month = {09/2019}, pages = {399-405}, doi = {10.1111/tbj.13480}, author = {Gabrielle Gauvin and Yeo, Caitlin T and Tamas Ungi and Shaila Merchant and Andras Lasso and Doris Jabs and Thomas Vaughan and John Rudan and Ross Walker and Gabor Fichtinger and C. Jay Engel} } @conference {Lund2019a, title = {Controlling virtual views in navigated breast conserving surgery}, booktitle = {SPIE Medical Imaging 2019}, year = {2019}, abstract = {

PURPOSE: Lumpectomy is the resection of a tumor in the breast while retaining as much healthy tissue as possible.
Navigated lumpectomy seeks to improve on the traditional technique by employing computer guidance to achieve the
complete excision of the cancer with optimal retention of healthy tissue. Setting up navigation in the OR relies on the
manual interactions of a trained technician to align three-dimensional virtual views to the patient{\textquoteright}s physical position
and maintain their alignment throughout surgery. This work develops automatic alignment tools to improve the
operability of navigation software for lumpectomies.
METHODS: Preset view buttons were developed to refine view setup to a single interaction. These buttons were
tested by measuring the reduction in setup time and the number of manual interactions avoided through their use. An
auto-center feature was created to ensure that three-dimensional models of anatomy and instruments were in the center
of view throughout surgery. Recorded data from 32 lumpectomy cases were replayed and the number of auto-center
view shifts was counted from the first cautery incision until the completion of the excision of cancerous tissue.
RESULTS: View setup can now be performed in a single interaction compared to an average of 13 interactions
(taking 83 seconds) when performed manually. The auto-center feature was activated an average of 33 times in the
cases studied (n=32).
CONCLUSION: The auto-center feature enhances the operability of the surgical navigation system, reducing the
number of manual interactions required by a technician during the surgery. This feature along with preset camera view
options are instrumental in the shift towards a completely surgeon-operable navigated lumpectomy system.

}, author = {Shaun Lund and Thomas Vaughan and Tamas Ungi and Andras Lasso and Mark Asselin and Caitlin Yeo and C. Jay Engel and Gabor Fichtinger} } @conference {Connolly2019a, title = {Mechanically-Controlled Spectroscopic Imaging for Tissue Classification}, booktitle = {SPIE Medical Imaging 2019: Image-Guided Procedures, Robotic Interventions, and Modeling}, volume = {10951}, year = {2019}, month = {03/2019}, address = {San Diego, California}, doi = {https://doi.org/10.1117/12.2512481}, author = {Laura Connolly and Tamas Ungi and Andras Lasso and Thomas Vaughan and Mark Asselin and Parvin Mousavi and Scott Yam and Gabor Fichtinger} } @article {Vaughan2019a, title = {Needle Navigation and Catheter Reconstruction for Breast Brachytherapy Using Open Source Software}, journal = {Acta Polytechnica Hungarica}, volume = {16}, number = {8}, year = {2019}, month = {09/2019}, pages = {99-118}, abstract = {

Abstract: Interstitial breast brachytherapy is a method to deliver radiation therapy directly to the site of cancer. It is a challenging procedure because of issues in localizing the seroma, needles, and catheters within the soft tissue. In this paper we present two open-source technologies based on electromagnetic tracking: a navigation system to help target needles using a tracked needle guide, and software for electromagnetic reconstruction of catheter paths. These technologies were validated phantom studies. We found that the navigation system helped a radiation oncologist to target needles more accurately than under ultrasound guidance (60 needles under each condition, 3.8 vs 3.3 mm placement error, p = 0.04) and that reconstructed catheter paths were accurate within 0.6 mm to those determined on CT scans (144 catheters were compared to the 1.2 mm voxel size of CT scans, p \< 0.001). We conclude that these technologies accurately localize anatomy and instruments in our study.

}, author = {Thomas Vaughan and H Brastianos and Tamas Ungi and Andras Lasso and Conrad Falkson and Gabor Fichtinger} } @article {Lia2019a, title = {Usability and accuracy of an electromagnetically tracked partial nephrectomy navigation system}, year = {2019}, month = {03/2019}, author = {H. Lia and Zachary M C Baum and Thomas Vaughan and Tamas Ungi and McGregor, T. and Gabor Fichtinger} } @article {Harish2017b, title = {An application of redundant sensors for intraoperative electromagnetic tracking error monitoring}, year = {2017}, address = {London, ON, Canada}, author = {Vinyas Harish and E Bibic and Andras Lasso and M. Holden and Thomas Vaughan and Zachary M C Baum and Tamas Ungi and Gabor Fichtinger} } @article {Brastianos2016c, title = {Demonstration of Catheter Insertion Using Electromagnetic Guidance in Breast Brachytherapy}, volume = {Radiother Oncol 123}, year = {2017}, month = {05/2017}, pages = {S91}, author = {Harry Brastianos and Thomas Vaughan and Andras Lasso and Mary Westerland and James Gooding and Tamas Ungi and Gabor Fichtinger and Conrad Falkson} } @article {Vaughan2017b, title = {Electromagnetically-generated catheter paths for breast brachytherapy}, year = {2017}, author = {Thomas Vaughan and Harry Brastianos and Andras Lasso and Tamas Ungi and Conrad Falkson and Gabor Fichtinger} } @conference {Harish2017a, title = {Monitoring electromagnetic tracking error using redundant sensors}, booktitle = {SPIE Medical Imaging 2017}, year = {2017}, publisher = {SPIE Society for Optics and Photonics}, organization = {SPIE Society for Optics and Photonics}, address = {Orlando, FL, USA}, abstract = {

PURPOSE: The intraoperative measurement of tracking error is crucial to ensure the reliability of electromagnetically navigated procedures. For intraoperative use, methods need to be quick to set up, easy to interpret, and not interfere with the ongoing procedure. Our goal was to evaluate the feasibility of using redundant electromagnetic sensors to alert users to tracking error in a navigated intervention setup. METHODS: Electromagnetic sensors were fixed to a rigid frame around a region of interest and on surgical tools. A software module was designed to detect tracking error by comparing real-time measurements of the differences between inter-sensor distances and angles to baseline measurements. Once these measurements were collected, a linear support vector machine-based classifier was used to predict tracking errors from redundant sensor readings. RESULTS: Measuring the deviation in the reported inter-sensor distance and angle between the needle and cautery served as a valid indicator for electromagnetic tracking error. The highest classification accuracy, 86\%, was achieved based on readings from the cautery when the two sensors on the cautery were close together. The specificity of this classifier was 93\% and the sensitivity was 82\%. CONCLUSION: Placing redundant electromagnetic sensors in a workspace seems to be feasible for the intraoperative detection of electromagnetic tracking error in controlled environments. Further testing should be performed to optimize the measurement error threshold used for classification in the support vector machine, and improve the sensitivity of our method before application in real procedures.\ 

}, author = {Vinyas Harish and Eden Bibic and Andras Lasso and M. Holden and Thomas Vaughan and Zachary M C Baum and Tamas Ungi and Gabor Fichtinger} } @article {Brastianos2017b, title = {Real Time Electomagnetic Reconstruction of Catheter Paths in Multi-Catheter Interstitial Brachytherapy: A Phantom Model}, volume = {Int J Radiat Oncol Biol Phys 99}, year = {2017}, month = {10/2017}, pages = {E642}, author = {Harry Brastianos and Thomas Vaughan and Andras Lasso and Mary Westerland and James Gooding and Gabor Fichtinger and Conrad Falkson} } @article {Vaughan2017a, title = {Virtual views controlled by surgical tools for computer assisted interventions}, year = {2017}, author = {Thomas Vaughan and Tamas Ungi and Andras Lasso and Gabrielle Gauvin and C. Jay Engel and John Rudan and Gabor Fichtinger} } @conference {Heffernan2016, title = {Accuracy of lesion boundary tracking in navigated breast tumor excision}, booktitle = {SPIE Medical Imaging 2016}, volume = {9786}, year = {2016}, month = {03/2016}, pages = {97860Y-1-6}, address = {San Diego, CA, USA}, doi = {10.1117/12.2217017}, url = {http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2505913\&resultClick=1}, author = {Emily Heffernan and Tamas Ungi and Thomas Vaughan and Padina Pezeshki and Andras Lasso and Gabrielle Gauvin and John Rudan and C. Jay Engel and Evelyn Morin and Gabor Fichtinger} } @article {Vaughan2016a, title = {Catheter targeting under electromagnetic guidance in breast brachytherapy {\textendash} a demonstration of concept}, volume = {Int J CARS}, number = {Suppl 1}, year = {2016}, month = {05/2016}, pages = {S60-62}, keywords = {Brachytherapy, breast}, author = {Thomas Vaughan and Harry Brastianos and Andras Lasso and Mary Westerland and Tamas Ungi and Conrad Falkson and Gabor Fichtinger} } @article {Brastianos2016a, title = {Electromagnetic tracking for catheter insertion guidance for HDR breast brachytherapy: demonstration of concept in phantoms}, volume = {Radiother Oncol 120}, year = {2016}, month = {09/2016}, pages = {S73-S74}, address = {Banff, AB, Canada}, author = {H Brastianos and Thomas Vaughan and Andras Lasso and M Westerland and James Gooding and Gabor Fichtinger and Conrad Falkson} } @article {Brastianos2016b, title = {Electromagnetic tracking for catheter insertion guidance for HDR breast brachytherapy: a phantom experiment}, volume = {Int J Radiat Oncol Biol Phys 96}, year = {2016}, month = {09/2016}, pages = {E643}, address = {Boston, MA, USA}, author = {H Brastianos and Thomas Vaughan and Andras Lasso and M Westerland and James Gooding and Gabor Fichtinger and Conrad Falkson} } @article {Vaughan2016b, title = {Electromagnetically-guided catheter insertions in breast phantoms for brachytherapy}, year = {2016}, month = {Submitted}, keywords = {Brachytherapy, breast}, author = {Thomas Vaughan and Harry Brastianos and Andras Lasso and Mary Westerland and Tamas Ungi and Conrad Falkson and Gabor Fichtinger} } @conference {Ungi2016c, title = {Intraoperative user interface for navigated breast tumor surgery}, booktitle = {Computer Assisted Radiology and Surgery, 30th International Congress}, volume = {11}, year = {2016}, month = {05/2016}, pages = {S108-9}, publisher = {Springer}, organization = {Springer}, address = {Heidelberg, Germany}, doi = {10.1007/s11548-016-1412-5}, author = {Tamas Ungi and Thomas Vaughan and Gabrielle Gauvin and Padina Pezeshki and Andras Lasso and C. Jay Engel and John Rudan and Gabor Fichtinger} } @conference {Carter2016a, title = {Visual feedback mounted on surgical tool: proof of concept}, booktitle = {SPIE Medical Imaging 2016}, volume = {9786}, year = {2016}, month = {In Press}, address = {San Diego, CA, USA}, author = {Kaci Carter and Thomas Vaughan and M. Holden and Gabrielle Gauvin and Padina Pezeshki and Andras Lasso and Tamas Ungi and Evelyn Morin and John Rudan and C. Jay Engel and Gabor Fichtinger} } @article {Vaughan2015, title = {Hole filling with oriented sticks in ultrasound volume reconstruction}, journal = {J. Med. Imag.}, volume = {2}, number = {3}, year = {2015}, author = {Thomas Vaughan and Andras Lasso and Tamas Ungi and Gabor Fichtinger} } @article {Ungi2015b, title = {Navigated breast tumor excision using electromagnetically tracked ultrasound and surgical instruments}, journal = {IEEE Transactions on Biomedical Engineering}, year = {2015}, month = {08/2015 }, abstract = {

OBJECTIVE:

Lumpectomy, breast conserving tumor excision, is the standard surgical treatment in early stage breast cancer. A common problem with lumpectomy is that the tumor may not be completely excised, and additional surgery becomes necessary. We investigated if a surgical navigation system using intraoperative ultrasound improves the outcomes of lumpectomy, and if such a system can be implemented in the clinical environment.

METHODS:

Position sensors were applied on the tumor localization needle, the ultrasound probe, and the cautery, and three-dimensional navigation views were generated using real time tracking information. The system was tested against standard wire-localization procedures on phantom breast models by eight surgical residents. Clinical safety and feasibility was tested in six palpable tumor patients undergoing lumpectomy by two experienced surgical oncologists.

RESULTS:

Navigation resulted in significantly less tissue excised compared to control procedures (10.3 {\textpm} 4.4 vs. 18.6 {\textpm} 8.7 g, p = 0.01) and lower number of tumorpositive margins (1/8 vs. 4/8) in the phantom experiments. Excision-tumor distance was also more consistently outside the tumor margins with navigation in phantoms. The navigation system has been successfully integrated in an operating room, and user experience was rated positively by surgical oncologists.

CONCLUSION:

Electromagnetic navigation may improve the outcomes of lumpectomy by making the tumor excision more accurate.

SIGNIFICANCE:

Breast cancer is the most common cancer in women, and lumpectomy is its first choice treatment. Therefore, improvement of lumpectomy outcomes have a significant impact on a large patient population.

}, issn = {0018-9294}, doi = {10.1109/TBME.2015.2466591}, url = {http://www.ncbi.nlm.nih.gov/pubmed/26302503}, author = {Tamas Ungi and Gabrielle Gauvin and Andras Lasso and Yeo, Caitlin T and Padina Pezeshki and Thomas Vaughan and Kaci Carter and John Rudan and C. Jay Engel and Gabor Fichtinger} } @mastersthesis {Vaughan2014a, title = {Generating Patient-Specific 3D Models using a Pointing Device}, year = {2014}, month = {08/2014}, school = {Queen{\textquoteright}s University}, type = {masters}, address = {Kingston, Ontario}, url = {https://qspace.library.queensu.ca/handle/1974/12400}, author = {Thomas Vaughan} } @article {Vaughan2012, title = {Ultrasound Volume Reconstruction: Open-Source Implementation with Hole Filling Functionality}, year = {2012}, month = {09/2012}, address = {Boston, MA}, author = {Thomas Vaughan and Andras Lasso and Gabor Fichtinger} }