@conference {Poulin2017, title = {Validation Of MRI To US Registration For Focal Hdr Prostate Brachytherapy Treatment}, booktitle = {Annual Scientific Meeting of the American Brachytherapy Society}, volume = {16}, number = {3}, year = {2017}, pages = {S56-S57}, publisher = {Elsevier}, organization = {Elsevier}, address = {Boston, MA, USA}, keywords = {Brachytherapy, contour propagation, MRI, Ultrasound}, issn = {1538-4721}, doi = {http://dx.doi.org/10.1016/j.brachy.2017.04.093}, url = {http://www.brachyjournal.com/article/S1538-4721(17)30154-X/fulltext}, author = {Eric Poulin}, editor = {Karim Boudam and Csaba Pinter and Samuel Kadoury and Andras Lasso and Gabor Fichtinger and Cynthia Menard} } @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} } @conference {Dehghan2016, title = {CT AND MRI FUSION FOR POSTIMPLANT PROSTATE BRACHYTHERAPY EVALUATION}, booktitle = {IEEE Int. Symp on Biomedical Imaging}, year = {2016}, month = {04/2016}, pages = {625-628}, abstract = {

Postoperative evaluation of prostate brachytherapy is typically
performed using CT, which does not have sufficient
soft tissue contrast for accurate anatomy delineation. MR-CT
fusion enables more accurate localization of both anatomy
and implanted radioactive seeds, and hence, improves the
accuracy of postoperative dosimetry. We propose a method
for automatic registration of MR and CT images without a
need for manual initialization. Our registration method employs
a point-to-volume registration scheme during which
localized seeds in the CT images, produced by commercial
treatment planning systems as part of the standard of care,
are rigidly registered to preprocessed MRI images. We tested
our algorithm on ten patient data sets and achieved an overall
registration error of 1.6 {\textpm} 0.8mm with a running time of less
than 20s. With high registration accuracy and computational
speed, and no need for manual intervention, our method has
the potential to be employed in clinical applications.

}, keywords = {Brachytherapy, Prostate}, author = {Ehsan Dehghan and Yi Le and Junghoon Lee and Danny Y Song and Gabor Fichtinger and Jerry L. Prince} } @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} } @article {MPeikari2012, title = {Characterization of ultrasound elevation beamwidth artifacts for prostate brachytherapy needle insertion}, journal = {Medical Physics}, volume = {39}, year = {2012}, month = {01/2012}, pages = {246-256}, abstract = {

Purpose: Ultrasound elevation beamwidth leads to image artefacts and uncertainties in localizing objects (such as a surgical needle) in ultrasound images. We examined the clinical significance of errors caused by elevation beamwidth artefacts and imaging parameters in needle insertion procedures. Method: Beveled prostate brachytherapy needles were inserted through all holes of a grid template under real-time transrectal ultrasound (TRUS) guidance. The needle tip position as indicated by the TRUS image was compared to their observed physical location. A new device was developed to measure the ultrasound elevation beamwidth. Result: Imaging parameters of the TRUS scanner have direct impact on the localization error ranging from 0.5 mm upto 4 mm. The smallest localization error was observed laterally close to the center of the grid template, and axially within the beam{\textquoteright}s focal zone. Largest localization error occurs laterally around both sides of the grid template, and axially within the beam{\textquoteright}s far field. we also found that the localization errors vary with both lateral and elevation offsets. Conclusion: We found properly adjusting the TRUS imaging settings to lower the ultrasound gain and power effectively minimized the appearance of elevation beamwidth artefacts and in turn reduced the localization errors of the needle tip.

}, keywords = {Brachytherapy, localization error, main lobe, side lobe, ultrasound imaging}, issn = {0094-2405}, doi = {10.1118/1.3669488}, url = {http://online.medphys.org/resource/1/mphya6/v39/i1/p246_s1}, author = {Mohammad Peikari and Thomas K. Chen and Andras Lasso and Tamas Heffter and E. Clif Burdette and Gabor Fichtinger} } @article {Tokuda2012, title = {Preclinical evaluation of an MRI-compatible pneumatic robot for angulated needle placement in transperineal prostate interventions}, journal = {International Journal of Computer Assisted Radiology and Surgery (IJCARS)}, year = {2012}, abstract = {

Purpose. To support transperineal prostate biopsies in a closed-bore magnetic resonance imaging (MRI) scanner, we developed a small profile MRI-compatible pneumatic needle placement robot that can angulate a needle insertion path into a large accessible target volume. We performed a preclinical evaluation of the robot{\textquoteright}s targeting accuracy with angulated needle insertion in a 3 Tesla clinical MRI. Methods. Angulation of the needle insertion path is achieved by a four degrees-of-freedom (4-DOF) mechanism with two parallel triangular structures. The robot is integrated with navigation software that allows an operator to plan angulated needle insertion by selecting a target and an entry point. The targeting error was evaluated while the angle between the needle insertion path and the static magnetic field was between -5.7{\textdegree} and 5.7{\textdegree} horizontally and between -5.7{\textdegree} and 4.3{\textdegree} vertically in the MRI scanner after sterilizing and draping the device. Results. The needle placement robot successfully positioned the needle with angulated insertion as specified on the navigation software. The overall targeting error was 0.8 {\textpm} 0.5 mm along the horizontal axis and 0.8 {\textpm} 0.8 mm along the vertical axis. The two-dimensional root-mean-square targeting error on the axial slices as containing the targets was 1.4 mm. Conclusions. Our preclinical evaluation demonstrated that the MRI-compatible pneumatic needle placement robot with the 4-DOF parallel kinematic structure with the capability to angulate the needle insertion path provides sufficient targeting accuracy for clinical MRI-guided prostate interventions.

}, keywords = {Biopsy, Brachytherapy, medical robotics, MRI-guided therapy, prostate cancer}, doi = {10.1007/s11548-012-0750-1}, url = {http://www.springerlink.com/content/tl77lrh211608j70/}, author = {Junichi Tokuda and Sam Sang-Eun Song and Gregory Fischer and Iulian Iordachita and Reza Seifabadi and Nathan Bongjoon Cho and Kemal Tuncali and Gabor Fichtinger and Clare M Tempany and Nobuhiko Hata} } @article {Dehghan2011a, title = {Brachytherapy Seed Reconstruction with Joint-Encoded C-Arm Single-Axis Rotation and Motion Compensation}, journal = {Medical Image Analysis}, volume = {15}, year = {2011}, month = {10/2011}, pages = {760 {\textendash} 771}, keywords = {Brachytherapy, C-arm Motion compensation, prostate cancer, Seed reconstruction}, doi = {10.1016/j.media.2011.05.017}, author = {Ehsan Dehghan and Ameet K. Jain and Mehdi Moradi and Xu Wen and William J. Morris and Septimiu E. Salcudean and Gabor Fichtinger} } @article {Pompeu-Robinson2011, title = {Immobilization and Catheter Guidance for Breast Brachytherapy}, journal = {International Journal of Computer Assisted Radiology and Surgery}, volume = {Online First}, year = {2011}, month = {05/2011}, abstract = {

Purpose: Brachytherapy is an important mode of breast cancer treatment; however, improvements in both treatment planning and delivery are needed. In order to meet these specific needs, integration of pre-operative imaging, supplemented by computerized surgical planning and mathematical optimization were used to develop and test an intra-operative immobilization and catheter guidance system. Method: A custom template specific to each patient with optimally placed guide holes for catheter insertion was designed and fabricated. Creation of the template is based on a virtual reality reconstruction of the patient{\textquoteright}s anatomy from computed tomography imaging. The template fits on the patient{\textquoteright}s breast, immobilizing the soft tissue, and provides pre-planned catheter insertion holes for guidance to the tumor site. Agar-based phantom and target models were used for quantitative validation of the template by ascertaining the precision and accuracy of the templates. Results: Tests were performed on agar-based tissue models using computed tomography imaging for template planning and validation. Planned catheter tracks were compared to post-insertion image data and distance measurements from target location were used to create an error measure. Initial results yielded an average error of 4.5 mm. Once the workflow and template design were improved, an average error of 2.6 mm was observed, bringing the error close to a clinically acceptable range. Conclusion: Use of a patient-specific template for breast brachytherapy is feasible and may improve the procedure accuracy and outcome.

}, keywords = {Brachytherapy, Breast cancer, Guidance, Immobilization, Radiotherapy}, doi = {DOI 10.1007/s11548-011-0600-6}, author = {Alexandra M. Pompeu-Robinson and M. Kunz and Conrad Falkson and John Schreiner and C.P. Joshi and Gabor Fichtinger} } @article {Dehghan2011c, title = {Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis}, journal = {Medical Physics}, volume = {38}, number = {10}, year = {2011}, month = {10/2011}, pages = {5290 {\textendash} 5302}, keywords = {Brachytherapy, C-arm, motion compensation, Seed reconstruction, tomosynthesis}, author = {Ehsan Dehghan and Mehdi Moradi and Xu Wen and Danny French and Julio R. Lobo and William J. Morris and Septimiu E. Salcudean and Gabor Fichtinger} } @article {Lee2008a, title = {Prostate brachytherapy seed localization with Gaussian blurring and camera self-calibration}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {11}, number = {Pt 2}, year = {2008}, pages = {636{\textendash}643}, publisher = {Department of Electrical, Computer Engineering, Johns Hopkins University, Baltimore, MD, USA}, abstract = {

A tomosynthesis-based prostate brachytherapy seed localization method is described Gaussian-blurred images are computed from a limited number of X-ray images, and a 3-D volume is reconstructed by backprojection Candidate seed locations are extracted from the reconstructed volume, false positive seeds are removed by optimizing a local cost function In case where the estimated pose error is large, a self-calibration process corrects the estimation error of the intrinsic camera parameters, the translation of the pose in order to improve the reconstruction Simulation, phantom experiment results imply that the implanted seed locations can be estimated from four or five images depending on the number of seeds The algorithm was also validated using patient data, successfully localizing the implanted seeds

}, keywords = {Artifacts, Brachytherapy, Calibration, Computer-Assisted, Humans, instrumentation/methods/standards, Male, methods, methods/standards, Normal Distribution, Prostatic Neoplasms, Radiographic Image Interpretation, radiography/radiotherapy, Radiotherapy, Tomography, X-Ray Computed}, author = {Junghoon Lee and Xiaofeng Liu and Jerry L. Prince and Gabor Fichtinger} } @article {Hefny2008, title = {Quantification of edematic effects in prostate brachytherapy interventions}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {11}, number = {Pt 2}, year = {2008}, pages = {493{\textendash}500}, publisher = {School of Computing, Queen{\textquoteright}s University, Kingston, Ontario, Canada}, abstract = {

We present a quantitative model to analyze the detrimental effects of for edema on the quality of prostate brachytherapy implants We account for both tissue expansion, implant migration by mapping intra-operative ultrasound, post-implant CT We pre-process the ultrasound with a phase congruency filter, and map it to the volume CT using a B-spline deformable mutual information similarity metric To test the method, we implanted a standard training phantom with 48 seeds, imaged the phantom with ultrasound, CT, registered the two for ground truth Edema was simulated by distorting the CT volume by known transformations The objective was to match the distorted implant to the intra-operative ultrasound Performance was measured relative to ground truth We successfully mapped 100\% of deformed seeds to ground truth under edematic expansion up to 40\% of volume growth Seed matching performance was 98\% with random seed migration of 3mm superimposed on 10\% edematic volume growth This method promises to be clinically applicable as the first quantitative analysis tool to measure edematic implant deformations occurring between the operating room, post-operative CT imaging

}, keywords = {adverse effects, adverse effects/instrumentation, Algorithms, Automated, Brachytherapy, complications/radiotherapy, Computer-Assisted, Edema, etiology/radiography, Humans, Male, methods, Pattern Recognition, Prostatic Diseases, Prostatic Neoplasms, Prosthesis Implantation, Radiographic Image Enhancement, Radiographic Image Interpretation, Reproducibility of Results, Sensitivity, Specificity, Tomography, Treatment Outcome, X-Ray Computed}, author = {Mohamed Hefny and Purang Abolmaesumi and Zahra Karim-Aghaloo and David Gobbi and Randy Ellis and Gabor Fichtinger} } @article {Fichtinger2008b, title = {Robotic assistance for ultrasound-guided prostate brachytherapy}, journal = {Medical Image Analysis}, volume = {12}, number = {5}, year = {2008}, month = {06/2008}, pages = {535}, publisher = {Queen{\textquoteright}s University; 25 Union Street;725 Goodwin Hall; Kingston; ON; Canada gabor@cs queensu ca}, abstract = {

We present a robotically assisted prostate brachytherapy system, test results in training phantoms, Phase-I clinical trials The system consists of a transrectal ultrasound (TRUS), a spatially co-registered robot,fully integrated with an FDA-approved commercial treatment planning system The salient feature of the system is a small parallel robot affixed to the mounting posts of the template The robot replaces the template interchangeably,using the same coordinate system Established clinical hardware,workflow, calibration remain intact In all phantom experiments,we recorded the first insertion attempt without adjustment All clinically relevant locations in the prostate were reached Non-parallel needle trajectories were achieved The pre-insertion transverse, rotational errors (measured with a Polaris optical tracker relative to the template{\textquoteright}s coordinate frame) were 0 25 mm (STD=0 17 mm), 0 75 degrees (STD=0 37 degrees) In phantoms,needle tip placement errors measured in TRUS were 1 04 mm (STD=0 50mm) A Phase-I clinical feasibility, safety trial has been successfully completed with the system We encountered needle tip positioning errors of a magnitude greater than 4mm in only 2 of 179 robotically guided needles,in contrast to manual template guidance where errors of this magnitude are much more common Further clinical trials are necessary to determine whether the apparent benefits of the robotic assistant will lead to improvements in clinical efficacy, outcomes

}, keywords = {Brachytherapy, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, instrumentation, instrumentation/methods, Interventional, Male, Prostatic Neoplasms, Radiotherapy, radiotherapy/ultrasonography, Robotics, Ultrasonography}, doi = {10 1016/j media 2008 06 002}, url = {http://dx doi org/10 1016/j media 2008 06 002}, author = {Gabor Fichtinger and Jonathan Fiene and Christopher Kennedy and Gernot Kronreif and Iulian Iordachita and Danny Y Song and E. Clif Burdette and Peter Kazanzides} } @article {Tokuda2008, title = {Software strategy for robotic transperineal prostate therapy in closed-bore MRI}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {11}, number = {Pt 2}, year = {2008}, pages = {701{\textendash}709}, publisher = {Department of Radiology, Brigham, Women{\textquoteright}s Hospital, Harvard Medical School, 75 Francis St , Boston, MA 02115, USA tokuda@bwh harvard edu}, abstract = {

A software strategy to provide intuitive navigation for MRI-guided robotic transperineal prostate therapy is presented In the system, the robot control unit, the MRI scanner, and open-source navigation software are connected to one another via Ethernet to exchange commands, coordinates, and images Six states of the system called "workphases" are defined based on the clinical scenario to synchronize behaviors of all components The wizard-style user interface allows easy following of the clinical workflow On top of this framework, the software provides features for intuitive needle guidance: interactive target planning; 3D image visualization with current needle position; treatment monitoring through real-time MRI These features are supported by calibration of robot, image coordinates by the fiducial-based registration The performance test shows that the registration error of the system was 2 6 mm in the prostate area, and it displayed real-time 2D image 1 7 s after the completion of image acquisition

}, keywords = {Brachytherapy, Computer-Assisted, Humans, Image Interpretation, Interventional, Magnetic Resonance Imaging, Male, methods, Needles, pathology/radiotherapy, Prostatic Neoplasms, Radiotherapy, Robotics, Software, Software Design}, author = {Junichi Tokuda and Gregory Fischer and Csaba Csoma and Simon DiMaio and David Gobbi and Gabor Fichtinger and Clare M Tempany and Nobuhiko Hata} } @article {Jain2007, title = {Intra-operative 3D guidance in prostate brachytherapy using a non-isocentric C-arm}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {9{\textendash}17}, publisher = {Johns Hopkins University, USA}, abstract = {

Intra-operative guidance in Transrectal Ultrasound (TRUS) guided prostate brachytherapy requires localization of inserted radioactive seeds relative to the prostate Seeds were reconstructed using a typical C-arm, and exported to a commercial brachytherapy system for dosimetry analysis Technical obstacles for 3D reconstruction on a non-isocentric C-arm included pose-dependent C-arm calibration; distortion correction; pose estimation of C-arm images; seed reconstruction;, C-arm to TRUS registration In precision-machined hard phantoms with 40-100 seeds, we correctly reconstructed 99 8\% seeds with a mean 3D accuracy of 0 68 mm In soft tissue phantoms with 45-87 seeds, clinically realistic 15 degrees C-arm motion, we correctly reconstructed 100\% seeds with an accuracy of 1 3 mm The reconstructed 3D seed positions were then registered to the prostate segmented from TRUS In a Phase-1 clinical trial, so far on 4 patients with 66-84 seeds, we achieved intra-operative monitoring of seed distribution, dosimetry We optimized the 100\% prescribed iso-dose contour by inserting an average of 3 75 additional seeds, making intra-operative dosimetry possible on a typical C-arm, at negligible additional cost to the existing clinical installation

}, keywords = {Algorithms, Brachytherapy, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, Imaging, instrumentation/methods, Interventional, Intraoperative Care, Male, methods, Prostatic Neoplasms, Prosthesis Implantation, Radiographic Image Enhancement, Radiographic Image Interpretation, Radiography, radiography/radiotherapy, Radiotherapy, Reproducibility of Results, Sensitivity, Specificity, Three-Dimensional, Tomography, X-Ray Computed}, author = {Ameet K. Jain and Anton Degeut and Iulian Iordachita and Gouthami Chintalapani and Jack Blevins and Le Yi and Elwood Armour and E. Clif Burdette and Danny Y Song and Gabor Fichtinger} } @article {Liu2007, title = {Prostate implant reconstruction with discrete tomography}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 1}, year = {2007}, pages = {734{\textendash}742}, publisher = {Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA}, abstract = {

We developed a discrete tomography method for prostate implant reconstructions using only a limited number of X-ray projection images A 3D voxel volume is reconstructed by back-projection, using distance maps generated from the projection images The true seed locations are extracted from the voxel volume while false positive seeds are eliminated using a novel optimal geometry coverage model The attractive feature of our method is that it does not require exact seed segmentation of the X-ray images, it yields near 100\% correct reconstruction from only six images with an average reconstruction accuracy of 0 86 mm (std = 0 46mm)

}, keywords = {Brachytherapy, Computer-Assisted, Humans, Imaging, instrumentation/methods, Male, methods, Prostatic Neoplasms, Prosthesis Implantation, Radiographic Image Enhancement, Radiographic Image Interpretation, radiography/radiotherapy, Three-Dimensional}, author = {Xiaofeng Liu and Ameet K. Jain and Gabor Fichtinger} } @article {Fichtinger2007c, title = {Robotic assistance for ultrasound guided prostate brachytherapy}, journal = {Medical Image Computing and Computer-Assisted Intervention (MICCAI)}, volume = {4791}, year = {2007}, pages = {119{\textendash}127}, publisher = {The Johns Hopkins University, Baltimore, Maryland, USA gabor@cs jhu edu}, abstract = {

We present a robotically assisted prostate brachytherapy system, test results in training phantoms The system consists of a transrectal ultrasound (TRUS), a spatially co-registered robot integrated with an FDA-approved commercial treatment planning system The salient feature of the system is a small parallel robot affixed to the mounting posts of the template The robot replaces the template interchangeably, uses the same coordinate system Established clinical hardware, workflow, calibration are left intact In these experiments, we recorded the first insertion attempt without adjustment All clinically relevant locations were reached Non-parallel needle trajectories were achieved The pre-insertion transverse, rotational errors (measured with Polaris optical tracker relative to the template{\textquoteright}s coordinate frame) were 0 25mm (STD = 0 17mm), 0 75 degrees (STD = 0 37 degrees) The needle tip placement errors measured in TRUS were 1 04mm (STD = 0 50mm) The system is in Phase-I clinical feasibility, safety trials, under Institutional Review Board approval

}, keywords = {Brachytherapy, Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, instrumentation/methods, Interventional, Male, Prostatic Neoplasms, Radiotherapy, Radiotherapy Planning, radiotherapy/ultrasonography, Robotics, Ultrasonography}, author = {Gabor Fichtinger and Jonathan Fiene and Christopher Kennedy and Gernot Kronreif and Iulian Iordachita and Danny Y Song and E. Clif Burdette and Peter Kazanzides} } @article {Labat2007, title = {Toward optimal matching for 3D reconstruction of brachytherapy seeds}, journal = {Medical image computing and computer-assisted intervention (MICCAI)}, volume = {10}, number = {Pt 2}, year = {2007}, pages = {701{\textendash}709}, publisher = {Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA}, abstract = {

X-ray C-arm fluoroscopy is a natural choice for intra-operative seed localization in prostate brachytherapy Resolving the correspondence of seeds in the projection images can be modeled as an assignment problem that is NP-hard Our approach rests on the practical observation that the optimal solution has almost zero cost if the pose of the C-arm is known accurately This allowed us to to derive an equivalent problem of reduced dimensionality that, with linear programming, can be solved efficiently in polynomial time Additionally, our method demonstrates significantly increased robustness to C-arm pose errors when compared to the prior art Because under actual clinical circumstances it is exceedingly difficult to track the C-arm, easing on this constraint has additional practical utility

}, keywords = {Algorithms, Artificial Intelligence, Automated, Brachytherapy, Computer-Assisted, Image Enhancement, Image Interpretation, Imaging, instrumentation/methods, methods, Pattern Recognition, Phantoms, Prosthesis Implantation, Radiotherapy, Reproducibility of Results, Sensitivity, Specificity, Three-Dimensional, Tomography, X-Ray Computed}, author = {Christian Labat and Ameet K. Jain and Gabor Fichtinger and Jerry L. Prince} } @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 {Jain2005e, title = {Matching and reconstruction of brachytherapy seeds using the Hungarian algorithm (MARSHAL)}, journal = {Journal of Medical Physics}, volume = {32}, number = {11}, year = {2005}, month = {Nov}, pages = {3475{\textendash}3492}, abstract = {

Intraoperative dosimetric quality assurance in prostate brachytherapy critically depends on discerning the three-dimensional (3D) locations of implanted seeds The ability to reconstruct the implanted seeds intraoperatively will allow us to make immediate provisions for dosimetric deviations from the optimal implant plan A method for seed reconstruction from segmented C-arm fluoroscopy images is proposed The 3D coordinates of the implanted seeds can be calculated upon resolving the correspondence of seeds in multiple x-ray images We formalize seed-matching as a combinatorial optimization problem, which has salient features: (a) extensively studied solutions by the computer science community; (b) proof for the nonexistence of any polynomial time exact algorithm;, (c) a practical pseudo-polynomial algorithm that mostly runs in O(N3) time using any number of images We prove that two images are insufficient to correctly match the seeds, while a third image renders the matching problem to be of nonpolynomial complexity We utilize the special structure of the problem, propose a pseudopolynomial time algorithm Using three presegmented images, matching, reconstruction of brachytherapy seeds using the Hungarian algorithm achieved complete matching in simulation experiments;, 98 5\% in phantom experiments 3D reconstruction error for correctly matched seeds has a mean of 0 63 mm, and 0 9 mm for incorrectly matched seeds The maximum seed reconstruction error in each implant was typically around 1 32 mm Both on synthetic data, in phantom experiments, matching rate, reconstruction error achieved using presegmented images was found to be sufficient for prostate brachytherapy The algorithm is extendable to deal with arbitrary number of images without any loss in speed or accuracy The algorithm is sufficiently generic to provide a practical solution to any correspondence problem, across different imaging modalities, features

}, keywords = {Algorithms, Automated, Brachytherapy, Calibration, Computer Simulation, Computer-Assisted, Humans, Image Interpretation, Imaging, Male, methods, Models, Numerical Analysis, Pattern Recognition, Phantoms, Prostatic Neoplasms, Radiographic Image Enhancement, Radiographic Image Interpretation, Radiometry, Radiotherapy, Radiotherapy Dosage, Radiotherapy Planning, Reproducibility of Results, Statistical, Theoretical, Three-Dimensional, Time Factors, Ultrasonography}, author = {Ameet K. Jain and Yu Zhou and Tabish Mustufa and E. Clif Burdette and Gregory Chirikjian and Gabor Fichtinger} } @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} }