@article {Sciubba2010, title = {Percutaneous computed tomography fluoroscopy-guided conformal ultrasonic ablation of vertebral tumors in a rabbit tumor model. Laboratory investigation.}, journal = {J Neurosurg Spine}, volume = {13}, number = {6}, year = {2010}, month = {Dec}, pages = {773{\textendash}779}, publisher = {Department of Neurosurgery, Johns Hopkins University, Baltimore, Maryland 21287, USA. dsciubb1@jhmi.edu}, abstract = {

Radiofrequency ablation (RFA) has proven to be effective for treatment of malignant and benign tumors in numerous anatomical sites outside the spine. The major challenge of using RFA for spinal tumors is difficulty protecting the spinal cord and nerves from damage. However, conforming ultrasound energy to match the exact anatomy of the tumor may provide successful ablation in such sensitive locations. In a rabbit model of vertebral body tumor, the authors have successfully ablated tumors using an acoustic ablator placed percutaneously via computed tomography fluoroscopic (CTF) guidance.Using CTF guidance, 12 adult male New Zealand White rabbits were injected with VX2 carcinoma cells in the lowest lumbar vertebral body. At 21 days, a bone biopsy needle was placed into the geographical center of the lesion, down which an acoustic ablator was inserted. Three multisensor thermocouple arrays were placed around the lesion to provide measurement of tissue temperature during ablation, at thermal doses ranging from 100 to 1,000,000 TEM (thermal equivalent minutes at 43{\textdegree}C), and tumor volumes were given a tumoricidal dose of acoustic energy. Animals were monitored for 24 hours and then sacrificed. Pathological specimens were obtained to determine the extent of tumor death and surrounding tissue damage. Measured temperature distributions were used to reconstruct volumetric doses of energy delivered to tumor tissue, and such data were correlated with pathological findings.All rabbits were successfully implanted with VX2 cells, leading to a grossly apparent spinal and paraspinal tissue mass. The CTF guidance provided accurate placement of the acoustic ablator in all tumors, as corroborated through gross and microscopic histology. Significant tumor death was noted in all specimens without collateral damage to nearby nerve tissue. Tissue destruction just beyond the margin of the tumor was noted in some but not all specimens. No neurological deficits occurred in response to ablation. Reconstruction of measured temperature data allowed accurate assessment of volumetric dose delivered to tissues.Using a rabbit intravertebral tumor model, the authors have successfully delivered tumoricidal doses of acoustic energy via a therapeutic ultrasound ablation probe placed percutaneously with CTF guidance. The authors have thus established the first technical and preclinical feasibility study of controlled ultrasound ablation of spinal tumors in vivo.

}, keywords = {Animals, Carcinoma, Catheter Ablation, Fluoroscopy, instrumentation/methods, Lumbar Vertebrae, Male, Neoplasm Transplantation, Rabbits, Spinal Neoplasms, therapy, Tomography, X-Ray Computed}, doi = {10.3171/2010.5.SPINE09266}, url = {http://dx.doi.org/10.3171/2010.5.SPINE09266}, author = {Daniel M Sciubba and E. Clif Burdette and Jennifer J Cheng and William A Pennant and Joseph C Noggle and Rory J Petteys and Christopher Alix and Chris J Diederich and Gabor Fichtinger and Ziya L Gokaslan and Kieran P Murphy} } @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 {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 {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} }