@article {Krieger2007a, title = {Design and preliminary accuracy studies of an MRI-guided transrectal prostate intervention system}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {59{\textendash}67}, publisher = {Department of Mechanical Engineering, Johns Hopkins University, Baltimore, USA}, abstract = {

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration, subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders, mechanical scales Targeting accuracy of the system is evaluated in prostate phantom experiments Achieved targeting accuracy, procedure times were found to compare favorably with existing systems using passive, active tracking methods Moreover, the portable design of the system using only standard MRI image sequences, minimal custom scanner interfacing allows the system to be easily used on different MRI scanners

}, keywords = {Algorithms, Artificial Intelligence, Automated, Biopsy, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, Interventional, Magnetic Resonance Imaging, Male, methods, Needle, pathology/surgery, Pattern Recognition, Pilot Projects, Prostatectomy, Prostatic Neoplasms, Rectum, Reproducibility of Results, Robotics, Sensitivity, Specificity, Three-Dimensional, User-Computer Interface}, author = {Axel Krieger and Csaba Csoma and Iulian Iordachita and Peter Guion and Anurag K. Singh and Gabor Fichtinger and Whitcomb, Louis L.} } @article {Chowning2006, title = {A preliminary analysis and model of prostate injection distributions}, journal = {The Prostate}, volume = {66}, number = {4}, year = {2006}, month = {Mar}, pages = {344{\textendash}357}, publisher = {Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA schowning@mri jhu edu}, abstract = {

PURPOSE: Understanding the internal dynamics of prostate injections, particularly injection pattern distribution is a key step to developing new therapies for prostate disease that may be best served with a direct injection approach Due to excellent properties involving liquid contrast agents, MRI can be used for targeting, monitoring of injections into organs, tissues MATERIALS AND METHODS: Eleven intraprostatic injections were performed in vivo with canines using a custom transrectal guiding, imaging system for use in a standard 1 5 T MR scanner In addition, 25 injections were performed on excised cadaveric human prostates, using a MedRad Spectris injector system MRI was used to guide the injections, monitor intraparenchymal injection distribution RESULTS: T1, T2-weighted MR images were correlated with histology to produce three-dimensional data sets that can be used to analyze trends in injection patterns This analysis was used to develop strategies for injection prediction such as gadolinium pre-injections, diffusion-weighted imaging guidance In addition, a rough model of prostate injections is described, and a preliminary injection guide is developed that takes into account the individual clinician{\textquoteright}s goals for therapy CONCLUSIONS: MR visualization of injected therapeutic agents allows for prediction, monitoring of drug distributions, possibly improving efficacy, reducing side effects Injection analysis, modeling may be used to assist in optimizing clinical treatments that require or would benefit from focal parenchymal injections into the prostate

}, keywords = {Animals, Antineoplastic Agents, Dogs, drug therapy, Forecasting, Magnetic Resonance Imaging, Male, Models, pharmacokinetics/pharmacology, Prostate, Prostatic Neoplasms, Rectum, Theoretical}, doi = {10 1002/pros 20298}, url = {http://dx doi org/10 1002/pros 20298}, author = {Scott Chowning and Robert Susil and Axel Krieger and Gabor Fichtinger and Whitcomb, Louis L. and Ergin Atalar} } @article {Fichtinger2006, title = {Robotically assisted prostate brachytherapy with transrectal ultrasound guidance{\textendash}Phantom experiments}, journal = {Brachytherapy}, volume = {5}, number = {1}, year = {2006}, pages = {14{\textendash}26}, publisher = {Engineering Research Center, The Johns Hopkins University, Baltimore, MD 21218-2682, USA gabor@cs jhu edu}, abstract = {

PURPOSE: To report the preliminary experimental results obtained with a robot-assisted transrectal ultrasound (TRUS)-guided prostate brachytherapy system METHODS AND MATERIALS: The system consists of a TRUS unit, a spatially coregistered needle insertion robot, and an FDA-approved treatment planning, image-registered implant system The robot receives each entry/target coordinate pair of the implant plan, inserts a preloaded needle, and then the seeds are deposited The needles/sources are tracked in TRUS, thus allowing the plan to be updated as the procedure progresses RESULTS: The first insertion attempt was recorded for each needle, without adjustment All clinically relevant locations were reached in a prostate phantom Nonparallel, parallel needle trajectories were demonstrated Based on TRUS, the average transverse placement error was 2 mm (worst case 2 5 mm, 80\% less than 2 mm), and the average sagittal error was 2 5 mm (worst case 5 0 mm, 70\% less than 2 5 mm) CONCLUSIONS: The concept, technical viability of robot-assisted brachytherapy were demonstrated in phantoms The kinematically decoupled robotic assistant device is inherently safe Overall performance was promising, but further optimization is necessary to prove the possibility of improved dosimetry

}, keywords = {Anatomic, Brachytherapy, Endosonography, Equipment Design, Humans, instrumentation, Male, methods, Models, Prostatic Neoplasms, radiotherapy/ultrasonography, Rectum, Robotics}, doi = {10 1016/j brachy 2005 10 003}, url = {http://dx doi org/10 1016/j brachy 2005 10 003}, author = {Gabor Fichtinger and E. Clif Burdette and Attila Tanacs and Alexandru Patriciu and Dumitru Mazilu and Whitcomb, Louis L. and Dan Stoianovici} } @article {Susil2006, title = {Transrectal prostate biopsy and fiducial marker placement in a standard 1 5T magnetic resonance imaging scanner}, journal = {The Journal of Urology}, volume = {175}, number = {1}, year = {2006}, month = {Jan}, pages = {113{\textendash}120}, publisher = {Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA}, abstract = {

PURPOSE: We investigated the accuracy, feasibility of a system that provides transrectal needle access to the prostate concurrent with 1 5 Tesla MRI which previously has not been possible MATERIALS AND METHODS: In 5 patients with previously diagnosed prostate cancer, MRI guided intraprostatic placement of gold fiducial markers (4 procedures),/or prostate biopsy (3 procedures) was performed using local anesthesia RESULTS: Mean procedure duration was 76 minutes, all patients tolerated the intervention well Procedure related adverse events included self-limited hematuria, hematochezia following 3 of 8 procedures (all resolved in less than 1 week) Mean needle placement accuracy was 1 9 mm for the fiducial marker placement studies, 1 8 mm for the biopsy procedures Mean fiducial marker placement accuracy was 4 8 mm, the mean fiducial marker placement accuracy transverse to the needle direction was 2 6 mm All patients who underwent the procedure were able to complete their course of radiotherapy without delay or complication CONCLUSIONS: While studies of clinical usefulness are warranted, transrectal 1 5 T MRI guided prostate biopsy, fiducial marker placement is feasible using this system, providing new opportunities for image guided diagnostic, therapeutic prostate interventions

}, keywords = {Biopsy, Equipment Design, Feasibility Studies, Humans, instrumentation, instrumentation/methods, Magnetic Resonance Imaging, Male, Needle, pathology, Prostate, Prostatic Neoplasms}, doi = {10 1016/S0022-5347(05)00065-0}, url = {http://dx doi org/10 1016/S0022-5347(05)00065-0}, author = {Robert Susil and Cynthia Menard and Axel Krieger and Jonathan Coleman and Kevin Camphausen and Peter Choyke and Gabor Fichtinger and Whitcomb, Louis L. and Norman Coleman and Ergin Atalar} } @article {Krieger2005a, title = {Design of a novel MRI compatible manipulator for image guided prostate interventions}, journal = {IEEE Transactions on Biomedical Engineering}, volume = {52}, number = {2}, year = {2005}, month = {Feb}, pages = {306{\textendash}313}, abstract = {

This paper reports a novel remotely actuated manipulator for access to prostate tissue under magnetic resonance imaging guidance (APT-MRI) device, designed for use in a standard high-field MRI scanner The device provides three-dimensional MRI guided needle placement with millimeter accuracy under physician control Procedures enabled by this device include MRI guided needle biopsy, fiducial marker placements, and therapy delivery Its compact size allows for use in both standard cylindrical, open configuration MRI scanners Preliminary in vivo canine experiments, first clinical trials are reported

}, keywords = {Animals, Biopsy, Computer-Assisted, Dogs, Equipment Design, Equipment Failure Analysis, Feasibility Studies, Imaging, instrumentation/methods, Magnetic Resonance Imaging, Male, Micromanipulation, Needle, pathology/surgery, Prostate, Reproducibility of Results, Robotics, Sensitivity, Specificity, Surgery, Three-Dimensional}, doi = {10 1109/TBME 2004 840497}, url = {http://dx doi org/10 1109/TBME 2004 840497}, author = {Axel Krieger and Robert Susil and Cynthia Menard and Jonathan Coleman and Gabor Fichtinger and Ergin Atalar and Whitcomb, Louis L.} } @article {Susil2003, title = {System for MR image-guided prostate interventions: canine study}, journal = {Radiology}, volume = {228}, number = {3}, year = {2003}, month = {Sep}, pages = {886{\textendash}894}, abstract = {

The purpose of this study was to demonstrate the use of a transrectal system that enables precise magnetic resonance (MR) image guidance, monitoring of prostate interventions The system used a closed-bore 1 5-T MR imaging unit, enables one to take advantage of the higher signal-to-noise ratio achieved with traditional magnet designs, which is crucial for accurate targeting, monitoring of prostate interventions In the first of the four canine studies, reliable needle placement, with all needles placed within 2 mm of the desired target site, was achieved In two other studies, MR imaging was used to monitor distribution of injected contrast agent solution (gadopentetate dimeglumine mixed with trypan blue dye) in, around the prostate, thereby confirming that solution had been delivered to the desired tissue, also detecting faulty injections In the final study, accurate placement, MR imaging of brachytherapy seeds in the prostate were demonstrated The described system provides a flexible platform for a variety of minimally invasive MR image-guided therapeutic, diagnostic prostate interventions

}, keywords = {administration /\&/ dosage, administration /\&/ dosage/diagnostic use, Animals, Brachytherapy, Contrast Media, Dogs, Gadolinium DTPA, Injections, Intralesional, Magnetic Resonance Imaging, Male, methods, Prostate, Prostatic Neoplasms, Radiography, Radiotherapy, Trypan Blue}, doi = {10 1148/radiol 2283020911}, url = {http://dx doi org/10 1148/radiol 2283020911}, author = {Robert Susil and Axel Krieger and Andrew Derbyshire and Attila Tanacs and Whitcomb, Louis L. and Gabor Fichtinger and Ergin Atalar} }