@article {Pinter2012a, title = {SlicerRT {\textendash} Radiotherapy toolkit for 3D Slicer}, year = {2012}, month = {02/2012}, address = {Toronto, ON, Canada}, keywords = {Radiotherapy}, author = {Csaba Pinter and Andras Lasso and An Wang 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 {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 {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} } @conference {Karim-Aghaloo2008, title = {Towards detecting surgical clips in 3D ultrasound for target localization in radiation therapy: a study on tissue phantoms}, booktitle = {International Conference of the IEEE Engineering in Medicine and Biology Society}, volume = {2008}, year = {2008}, pages = {5282{\textendash}5285}, publisher = {Department of Electrical, Computer Engineering, Queens University, Kingston, ON K7L3N6, Canada}, organization = {Department of Electrical, Computer Engineering, Queens University, Kingston, ON K7L3N6, Canada}, abstract = {

A study is performed to measure the visibility of small surgical clips in 3D ultrasound volumes of a phantom as the first step towards using such clips as fiducial markers in radiation therapy Visibility is calculated as the contrast to noise ratio of the echo from the clip to the background The appearance of a resonance tail is also calculated using a moment analysis Contrast is found to be high, mostly independent of material, size of the clip All clips are visible, but the length of the tail is found to be dependent on clip orientation to the ultrasound beam The consistent visibility of the clips suggests they are suitable as fiducial markers in ultrasound, the dependency of the resonance tail on orientation provides an opportunity to distinguish clips from other specular reflectors

}, keywords = {Computer-Assisted, Equipment Design, Equipment Failure Analysis, Humans, Image Enhancement, Imaging, instrumentation, instrumentation/methods, methods, Phantoms, Radiotherapy, Reproducibility of Results, Sensitivity, Specificity, Surgical Instruments, Three-Dimensional, Ultrasonography}, doi = {10 1109/IEMBS 2008 4650406}, url = {http://dx doi org/10 1109/IEMBS 2008 4650406}, author = {Zahra Karim-Aghaloo and Prasad Shrawane and Purang Abolmaesumi and Gabor Fichtinger and Robert Rohling} } @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 {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 {Singh2007b, title = {Simultaneous integrated boost of biopsy proven and MRI defined dominant intra-prostatic lesions to 95 Gray with IMRT: early results of a phase I NCI study}, journal = {Radiation Oncology}, volume = {2}, year = {2007}, pages = {36}, publisher = {Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, USA singhanu@yahoo com}, abstract = {

BACKGROUND: To assess the feasibility, early toxicity of selective, IMRT-based dose escalation (simultaneous integrated boost) to biopsy proven dominant intra-prostatic lesions visible on MRI METHODS: Patients with localized prostate cancer, an abnormality within the prostate on endorectal coil MRI were eligible All patients underwent a MRI-guided transrectal biopsy at the location of the MRI abnormality Gold fiducial markers were also placed Several days later patients underwent another MRI scan for fusion with the treatment planning CT scan This fused MRI scan was used to delineate the region of the biopsy proven intra-prostatic lesion A 3 mm expansion was performed on the intra-prostatic lesions, defined as a separate volume within the prostate The lesion + 3 mm, the remainder of the prostate + 7 mm received 94 5/75 6 Gray (Gy) respectively in 42 fractions Daily seed position was verified to be within 3 mm RESULTS: Three patients were treated Follow-up was 18, 6, and 3 months respectively Two patients had a single intra-prostatic lesion One patient had 2 intra-prostatic lesions All four intra-prostatic lesions, with margin, were successfully targeted, treated to 94 5 Gy Two patients experienced acute RTOG grade 2 genitourinary (GU) toxicity One had grade 1 gastrointestinal (GI) toxicity All symptoms completely resolved by 3 months One patient had no acute toxicity CONCLUSION: These early results demonstrate the feasibility of using IMRT for simultaneous integrated boost to biopsy proven dominant intra-prostatic lesions visible on MRI The treatment was well tolerated

}, keywords = {adverse effects/methods, Biopsy, epidemiology, epidemiology/radiotherapy, Follow-Up Studies, Humans, Intensity-Modulated, Magnetic Resonance Imaging, Male, National Cancer Institute (U S ), Patient Selection, Prostatic Neoplasms, Questionnaires, Radiotherapy, Radiotherapy Dosage, United States}, doi = {10 1186/1748-717X-2-36}, url = {http://dx doi org/10 1186/1748-717X-2-36}, author = {Anurag K. Singh and Peter Guion and Nancy Sears-Crouse and Karen Ullman and Sharon Smith and Paul Albert and Gabor Fichtinger and Peter Choyke and Sheng Xu and Jochen Kruecker and Bradford Wood and Axel Krieger and Holly Ning} } @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 {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} }