@conference {Monfaredi2013a,
	title = {Design of a Decoupled MRI-compatible Force Sensor using Fiber Bragg Grating Sensors for Robot-assisted Prostate Interventions},
	booktitle = {SPIE},
	volume = {8671},
	year = {2013},
	month = {03/2013},
	address = {Orlando, Floirda},
	abstract = {<p>{During prostate needle insertion, the gland rotates and displaces resulting in needle placement inaccuracy. To compensate for this error, we proposed master-slave needle steering under real-time MRI in a previous study. For MRI-compatibility and accurate motion control, the master (and the slave) robot uses piezo actuators. These actuators however, are non-backdrivable. To cope with this issue, force sensor is required. Force sensor is also required at the slave side to reflect the insertion force to clinician{\textquoteright}s hand through the master robot. Currently, there is no MRI-compatible force sensor commercially available. In order to generate a combination of linear and rotary motions for needle steering, this study is seeking to develop a MRI-compatible 2 Degrees of Freedom (DOF) force/torque sensor. Fiber Brag Grating (FBG) strain measuring sensors which are proven to be MRI-compatible are used. The active element is made of phosphor-bronze and other parts are made of brass. The force and torque measurements are designed to be entirely decoupled. The sensor measures -20 to 20 N axial force with 0.1 N resolution, and -200 to 200 Nmm axial torque with 1 Nmm resolution. Analytical and Finite Element (FE) analyses are performed to ensure the strains are within the measurable range of the FBG sensors. The sensor is designed to be compact (diameter =15 mm</p>
},
	keywords = {FBG, force sensor, MRI -compatible},
	doi = {0.1117/12.2008160},
	author = {Monfaredi, R and Reza Seifabadi and Gabor Fichtinger and Iulian Iordachita}
}
@article {Seifabadi2011,
	title = {Robotic System for MRI-guided Prostate Biopsy: Feasibility of Teleoperated Needle Insertion and ex vivo Phantom Study},
	journal = {International Journal of Computer Aided Radiology and Surgery (IJCARS)},
	year = {2011},
	abstract = {<p>"Purpose": Magnetic Resonance Imaging (MRI) combined with robotic assistance has the potential to improve on clinical outcomes of biopsy and local treatment of prostate cancer. "Methods": We report the workspace optimization and phantom evaluation of a five Degree of Freedom (DOF) parallel pneumatically actuated modular robot for MRI-guided prostate biopsy. To shorten procedure time and consequently increase patient comfort and system accuracy, a prototype of a MRI-compatible master-slave needle driver module using piezo motors was also added to the base robot. "Results": Variable size workspace was achieved using appropriate link length, compared to the previous design. The 5-DOF targeting accuracy demonstrated an average error of 2.5 mm (STD=1.37 mm) in a realistic phantom inside a 3T magnet with a bevel-tip 18G needle. The average position tracking error of the master-slave needle driver was always below 0.1 mm. "Conclusion": Phantom experiments showed sufficient accuracy for manual prostate biopsy. Also, the implementation of teleoperated needle insertion was feasible and accurate. These two together suggest feasibility of accurate fully actuated needle placement into prostate while keeping the clinician supervision over the task.</p>
},
	keywords = {accuracy evaluation, MRI -compatible, phantom study, Pneumatic Robot, Teleoperation, Transperineal prostate biopsy},
	doi = {10.1007/s11548-011-0598-9},
	url = {http://www.springerlink.com/content/h53329764x605415/fulltext.pdf},
	author = {Reza Seifabadi and Sam Sang-Eun Song and Axel Krieger and Nathan Bongjoon Cho and Junichi Tokuda and Gabor Fichtinger and Iulian Iordachita}
}
