@conference {Wiercigroch2020a,
	title = {Force and torque feedback in endoscopic vessel harvesting},
	booktitle = {Medical Imaging 2020: Image-Guided Procedures, Robotic Inverventions and Modeling},
	volume = {11315},
	year = {2020},
	month = {2020},
	publisher = {SPIE},
	organization = {SPIE},
	address = {Houston, Texas, United States},
	doi = {https://doi.org/10.1117/12.2550160},
	author = {Julia Wiercigroch and Keyvan Hashtrudi-Zaad and Tamas Ungi and Gianluigi Bisleri and Gabor Fichtinger}
}
@conference {doi:10.1117/12.2217189,
	title = {Investigation of permanent magnets in low-cost position tracking},
	booktitle = {Proc. SPIE},
	year = {2016},
	pages = {97862F-97862F-9},
	abstract = {<p>PURPOSE: Low cost portable ultrasound systems could see improved utility if similarly low cost portable trackers were developed. Permanent magnet based tracking systems potentially offer adequate tracking accuracy in a small workspace suitable for ultrasound image reconstruction. In this study the use of simple permanent magnet tracking techniques is investigated to determine feasibility for use in an ultrasound tracking system. METHODS: Permanent magnet tracking requires finding a position input into a field model which minimizes the error between the measured field, and the field expected from the model. A simulator was developed in MATLAB to determine the effect of sources of error in permanent magnet tracking systems. Insights from the simulations were used to develop a calibration and tracking experiment to determine the accuracy of a simple and low cost permanent magnet tracking system. RESULTS: Simulation and experimental results show permanent magnet based tracking to be highly sensitive to errors in sensor measurements, calibration and experimental setup. The reduction in field strength of permanent magnets lowers with the cube of distance, which leads to very poor signal-to-noise ratios at distances above 20 cm. Small errors in experimental setup also led to high tracking error. CONCLUSION: Permanent magnet tracking was found to be less accurate than is clinically useful, and highly sensitive to errors in sensors and experimental setup. Sensor and calibration limitations make simple permanent magnet tracking systems a poor choice given the present state of sensor technology.</p>
},
	doi = {10.1117/12.2217189},
	url = {http://dx.doi.org/10.1117/12.2217189},
	author = {Anderson, Ryan and Andras Lasso and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@article {Sadjadi2015b,
	title = {Simultaneous electromagnetic tracking and calibration for dynamic field distortion compensation},
	journal = {IEEE Transactions on Biomedical Engineering (TBME)},
	year = {2015},
	month = {11/2015},
	doi = {10.1109/TBME.2015.2502138},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@article {Sadjadi2015a,
	title = {Simultaneous Localization and Calibration for Electromagnetic Tracking Systems},
	journal = {The International Journal of Medical Robotics and Computer Assisted Surgery (IJMRCAS)},
	year = {2015},
	doi = {10.1002/rcs},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@article {Sadjadi2014a,
	title = {Development and Evaluation of a Needle Deflection Estimation Method},
	year = {2014},
	month = {03/2014},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@conference {Sadjadi2014c,
	title = {Electromagnetic tracking performance analysis and optimization},
	booktitle = {International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)},
	year = {2014},
	month = {09/2014},
	author = {Yu Qi and Hossein Sadjadi and Yeo, Caitlin T and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@article {Sadjadi2014b,
	title = {Needle Deflection Estimation: Prostate Brachytherapy Phantom Experiments},
	journal = {International Journal of Computer Assisted Radiology and Surgery (IJCARS)},
	year = {2014},
	month = {03/2014},
	doi = {10.1007/s11548-014-0985-0},
	url = {http://dx.doi.org/10.1007/s11548-014-0985-0},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@article {Anderson2014,
	title = {Proposed Feasibility Analysis of Low Cost Inertial Freehand Ultrasound Position Tracking},
	year = {2014},
	address = {Toronto, Ontario},
	author = {Anderson, Ryan and Andras Lasso and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@conference {Sadjadi2013b,
	title = {Experimental evaluation of needle deflection estimation for brachytherapy},
	booktitle = {Computer Assisted Radiology and Surgery (CARS 2013)},
	year = {2013},
	month = {03/2013},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Xu, Helen and Gabor Fichtinger}
}
@article {Sadjadi2013a,
	title = {Fusion of Electromagnetic Trackers to Improve Needle Deflection Estimation: Simulation Study},
	journal = {IEEE Transactions on Biomedical Engineering},
	volume = {60},
	year = {2013},
	month = {10/2013},
	pages = {2706 - 2715},
	issn = {0018-9294},
	doi = {10.1109/TBME.2013.2262658},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
@conference {Sadjadi2012,
	title = {Needle Deflection Estimation using Fusion of Electromagnetic Trackers},
	booktitle = {34th Annual International Conference of the IEEE EMBS (EMBC 2012)},
	year = {2012},
	month = {08/28/2012},
	pages = {952-955},
	address = {San Diego, California USA},
	abstract = {<p>We present a needle deflection estimation method to compensate for needle bending during insertion into deformable tissue. We combine a kinematic needle deflection estimation model, electromagnetic (EM) trackers, and a Kalman filter (KF). We reduce the impact of error from the needle deflection estimation model by using the fusion of two EM trackers to report the approximate needle tip position in real-time. One reliable EM tracker is installed on the needle base, and estimates the needle tip position using the kinematic needle deflection model. A smaller but much less reliable EM tracker is installed on the needle tip, and estimates the needle tip position through direct noisy measurements. Using a KF, the sensory information from both EM trackers is fused to provide a reliable estimate of the needle tip position with much reduced variance in the estimation error. We then implement this method to compensate for needle deflection during simulated prostate cancer brachytherapy needle insertion. At a typical maximum insertion depth of 15 cm, needle tip mean estimation error was reduced from 2.39 mm to 0.31 mm, which demonstrates the effectiveness of our method, offering a clinically practical solution.</p>
},
	author = {Hossein Sadjadi and Keyvan Hashtrudi-Zaad and Gabor Fichtinger}
}
