scispace - formally typeset
Search or ask a question
Author

Attila Tanacs

Bio: Attila Tanacs is an academic researcher from University of Szeged. The author has contributed to research in topics: Image registration & Image processing. The author has an hindex of 10, co-authored 33 publications receiving 793 citations. Previous affiliations of Attila Tanacs include Johns Hopkins University & General Electric.

Papers
More filters
Journal ArticleDOI
TL;DR: Results of preliminary experiments indicate that this robotic system may be suitable for transperineal needle placement into the prostate and shows potential in a variety of other percutaneous clinical applications.

196 citations

Patent
22 Apr 2003
TL;DR: In this article, a real-time imager is used to guide the insertion of a needle carrier into a natural or artificial cavity, guided by a real time imager, in a medical device or needle carrier.
Abstract: The end-effector (150) includes a sheath (152) and a medical device or needle carrier (154) that is disposed within the interior compartment (160) of the sheath. Aperture (162) is located in a portion of the sheath proximal a distal end of the sheath that is inserted into a natural or artificial cavity. This device is guided by a real-time imager.

120 citations

Journal ArticleDOI
TL;DR: The lack of correlation between the efficacy of therapy and occupancy of DAT may raise the question as to whether other mechanisms are involved in the effect of bupropion, and in good agreement with other PET studies.

90 citations

Journal ArticleDOI
TL;DR: The use of a transrectal system that enables precise magnetic resonance (MR) image guidance and monitoring of prostate interventions and provides a flexible platform for a variety of minimally invasive MR image-guided therapeutic and diagnostic prostate interventions is demonstrated.
Abstract: The purpose of this study was to demonstrate the use of a transrectal system that enables precise magnetic resonance (MR) image guidance and monitoring of prostate interventions. The system used a closed-bore 1.5-T MR imaging unit and enables one to take advantage of the higher signal-to-noise ratio achieved with traditional magnet designs, which is crucial for accurate targeting and 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 and around the prostate, thereby confirming that solution had been delivered to the desired tissue and also detecting faulty injections. In the final study, accurate placement and MR imaging of brachytherapy seeds in the prostate were demonstrated. The described system provides a flexible...

89 citations

Journal ArticleDOI
TL;DR: The concept and technical viability of robot-assisted brachytherapy were demonstrated in phantoms, and the kinematically decoupled robotic assistant device is inherently safe.

87 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A survey of the current state of research on needle insertion in soft tissue is presented, e.g. modeling needle insertion forces, modeling tissue deformation and needle deflection during insertion, robot-assisted needle insertion, and the effect of different trajectories on tissueDeformation.

658 citations

Journal ArticleDOI
TL;DR: Prostate cancer localized on magnetic resonance Imaging may be targeted using this novel magnetic resonance imaging/ultrasound fusion guided biopsy platform, and to determine which patients may benefit.

435 citations

Journal ArticleDOI
TL;DR: The charge of Task Group 186 (TG-186) is to provide guidance for early adopters of model-based dose calculation algorithms (MBDCAs) for brachytherapy (BT) dose calculations to ensure practice uniformity, with explicit recommendations based on the current state of knowledge.
Abstract: The charge of Task Group 186 (TG-186) is to provide guidance for early adopters of model-based dose calculation algorithms (MBDCAs) for brachytherapy (BT) dose calculations to ensure practice uniformity. Contrary to external beam radiotherapy, heterogeneity correction algorithms have only recently been made available to the BT community. Yet, BT dose calculation accuracy is highly dependent on scatter conditions and photoelectric effect cross-sections relative to water. In specific situations, differences between the current water-based BT dose calculation formalism (TG-43) and MBDCAs can lead to differences in calculated doses exceeding a factor of 10. MBDCAs raise three major issues that are not addressed by current guidance documents: (1) MBDCA calculated doses are sensitive to the dose specification medium, resulting in energy-dependent differences between dose calculated to water in a homogeneous water geometry (TG-43), dose calculated to the local medium in the heterogeneous medium, and the intermediate scenario of dose calculated to a small volume of water in the heterogeneous medium. (2) MBDCA doses are sensitive to voxel-by-voxel interaction cross sections. Neither conventional single-energy CT nor ICRU∕ICRP tissue composition compilations provide useful guidance for the task of assigning interaction cross sections to each voxel. (3) Since each patient-source-applicator combination is unique, having reference data for each possible combination to benchmark MBDCAs is an impractical strategy. Hence, a new commissioning process is required. TG-186 addresses in detail the above issues through the literature review and provides explicit recommendations based on the current state of knowledge. TG-43-based dose prescription and dose calculation remain in effect, with MBDCA dose reporting performed in parallel when available. In using MBDCAs, it is recommended that the radiation transport should be performed in the heterogeneous medium and, at minimum, the dose to the local medium be reported along with the TG-43 calculated doses. Assignments of voxel-by-voxel cross sections represent a particular challenge. Electron density information is readily extracted from CT imaging, but cannot be used to distinguish between different materials having the same density. Therefore, a recommendation is made to use a number of standardized materials to maintain uniformity across institutions. Sensitivity analysis shows that this recommendation offers increased accuracy over TG-43. MBDCA commissioning will share commonalities with current TG-43-based systems, but in addition there will be algorithm-specific tasks. Two levels of commissioning are recommended: reproducing TG-43 dose parameters and testing the advanced capabilities of MBDCAs. For validation of heterogeneity and scatter conditions, MBDCAs should mimic the 3D dose distributions from reference virtual geometries. Potential changes in BT dose prescriptions and MBDCA limitations are discussed. When data required for full MBDCA implementation are insufficient, interim recommendations are made and potential areas of research are identified. Application of TG-186 guidance should retain practice uniformity in transitioning from the TG-43 to the MBDCA approach.

418 citations

Journal ArticleDOI
TL;DR: There is evidence to suggest that antidepressants that enhance noradrenergic and dopaminergic activity may afford a therapeutic advantage over serotonergic antidepressants in the treatment of symptoms associated with a reduction in positive affect.
Abstract: Despite significant advances in pharmacologic therapy of depression over the past two decades, a substantial proportion of patients fail to respond or experience only partial response to serotonin re-uptake inhibitor antidepressants, resulting in chronic functional impairment. There appears to be a pattern of symptoms that are inadequately addressed by serotonergic antidepressants - loss of pleasure, loss of interest, fatigue and loss of energy. These symptoms are key to the maintenance of drive and motivation. Although these symptoms are variously defined, they are consistent with the concept of ;decreased positive affect'. Positive affect subsumes a broad range of positive mood states, including feelings of happiness (joy), interest, energy, enthusiasm, alertness and self-confidence. Although preliminary, there is evidence to suggest that antidepressants that enhance noradrenergic and dopaminergic activity may afford a therapeutic advantage over serotonergic antidepressants in the treatment of symptoms associated with a reduction in positive affect. Dopaminergic and noradrenergic agents, including the dual acting norepinephrine and dopamine re-uptake inhibitors, have demonstrated antidepressant activity in the absence of serotonergic function, showing similar efficacy to both tricyclic and serotonin re-uptake inhibitor antidepressants. Moreover, the norepinephrine and dopamine re-uptake inhibitor bupropion has been shown to significantly improve symptoms of energy, pleasure and interest in patients with depression with predominant baseline symptoms of decreased pleasure, interest and energy. Focusing treatment on the predominant or driving symptomatology for an individual patient with major depression could potentially improve rates of response and remission.

365 citations

Journal ArticleDOI
TL;DR: A system that fuses real-time transrectal ultrasound images with previously acquired endorectal coil MRI images for prostate biopsy guidance is presented here and retrospective clinical evaluation suggests that clinically acceptable spatial accuracy can be achieved.
Abstract: Targeted prostate biopsy is challenging because no currently established imaging modality is both accurate for prostate cancer diagnosis and cost-effective for real-time procedure guidance. A system that fuses real-time transrectal ultrasound images with previously acquired endorectal coil MRI images for prostate biopsy guidance is presented here. The system uses electromagnetic tracking and intraoperative image registration to superimpose the MRI data on the ultrasound image. Prostate motion is tracked and compensated for without the need for fiducial markers. The accuracy of the system in phantom studies was shown to be 2.4 ± 1.2 mm. The fusion system has been used in more than 20 patients to guide biopsies with almost no modification of the conventional protocol. Retrospective clinical evaluation suggests that clinically acceptable spatial accuracy can be achieved.

303 citations