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Sample records for image guided radio

  1. In vivo intracardiac OCT imaging through percutaneous access: towards image guided radio-frequency ablation

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Kang, Wei; Carrigan, Thomas; Bishop, Austin; Rosenthal, Noah; Arruda, Mauricio; Rollins, Andrew M.

    2012-01-01

    BACKGROUND Complete catheter-tissue contact and permanent tissue destruction are essential for efficient radio-frequency ablation (RFA) during cardiac arrhythmia treatment. Current methods of monitoring lesion formation are indirect and unreliable. We aim to develop optical coherence tomography (OCT) as an imaging guidance for RFA. OBJECTIVES The purpose of this study is to evaluate the feasibility of using OCT catheter to image endocardia wall in active beating hearts through percutaneous access. This is a critical step toward image guided RFA in a clinic setting. METHODS A cone-scanning forward-viewing OCT catheter was advanced into active beating hearts through percutaneous access in four swine. The OCT catheter was steered by an introducer to touch the endocardia wall. The images were then acquired at 10 frames per second at an axial resolution and lateral resolution of 15 μm. RESULTS We report the first in vivo intracardiac OCT imaging through percutaneous access with a thin and flexible OCT catheter. We are able to acquire high quality OCT images in active beating hearts, observe the polarization-related artifacts induced by the birefringence of myocardium and readily evaluate catheter-tissue contact. CONCLUSIONS It is feasible to acquire OCT images in beating hearts through percutaneous access. The observations indicate that OCT could be a promising technique for in vivo guidance of RFA.

  2. In vivo intracardiac optical coherence tomography imaging through percutaneous access: toward image-guided radio-frequency ablation

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Kang, Wei; Carrigan, Thomas; Bishop, Austin; Rosenthal, Noah; Arruda, Mauricio; Rollins, Andrew M.

    2011-11-01

    Complete catheter-tissue contact and permanent tissue destruction are essential for efficient radio-frequency ablation (RFA) during cardiac arrhythmia treatment. Current methods of monitoring lesion formation are indirect and unreliable. The purpose of this study is to evaluate the feasibility of using optical coherence tomography (OCT) catheter to image endocardial wall in actively beating hearts through percutaneous access. We reported the first in vivo intracardiac OCT imaging through percutaneous access with a thin and flexible OCT catheter. This is a critical step toward image-guided RFA in a clinical setting. A cone-scanning forward-viewing OCT catheter was advanced into beating hearts through percutaneous access in four swine. The OCT catheter was steered by an introducer to touch the endocardial wall. We are able to acquire high quality OCT images in beating hearts, observe the polarization-related artifacts induced by the birefringence of myocardium, and readily evaluate catheter-tissue contact. The observations indicate that OCT could be a promising technique for in vivo guidance of RFA.

  3. Radionuclide (131)I labeled reduced graphene oxide for nuclear imaging guided combined radio- and photothermal therapy of cancer.

    PubMed

    Chen, Lei; Zhong, Xiaoyan; Yi, Xuan; Huang, Min; Ning, Ping; Liu, Teng; Ge, Cuicui; Chai, Zhifang; Liu, Zhuang; Yang, Kai

    2015-10-01

    Nano-graphene and its derivatives have attracted great attention in biomedicine, including their applications in cancer theranostics. In this work, we develop 131I labeled, polyethylene glycol (PEG) coated reduced nano-graphene oxide (RGO), obtaining 131I-RGO-PEG for nuclear imaging guided combined radiotherapy and photothermal therapy of cancer. Compared with free 131I, 131IRGO- PEG exhibits enhanced cellular uptake and thus improved radio-therapeutic efficacy against cancer cells. As revealed by gamma imaging, efficient tumor accumulation of 131I-RGO-PEG is observed after its intravenous injection. While RGO exhibits strong near-infrared (NIR) absorbance and could induce effective photothermal heating of tumor under NIR light irradiation, 131I is able to emit high-energy X-ray to induce cancer killing as the result of radio ionization effect. By utilizing the combined photothermal therapy and radiotherapy, both of which are delivered by a single agent 131IRGO- PEG, effective elimination of tumors is achieved in our animal tumor model experiments. Toxicology studies further indicate that 131I-RGO-PEG induces no appreciable toxicity to mice at the treatment dose. Our work demonstrates the great promise of combing nuclear medicine and photothermal therapy as a novel therapeutic strategy to realize synergistic efficacy in cancer treatment.

  4. Radiosensitizer-eluting nanocoatings on gold fiducials for biological in-situ image-guided radio therapy (BIS-IGRT)

    NASA Astrophysics Data System (ADS)

    Nagesha, D. K.; Tada, D. B.; Stambaugh, C. K. K.; Gultepe, E.; Jost, E.; Levy, C. O.; Cormack, R.; Makrigiorgos, G. M.; Sridhar, S.

    2010-10-01

    Image-guided radiation treatments (IGRT) routinely utilize radio-opaque implantable devices, such as fiducials or brachytherapy spacers, for improved spatial accuracy. The therapeutic efficiency of IGRT can be further enhanced by biological in situ dose painting (BIS-IGRT) of radiosensitizers through localized delivery within the tumor using gold fiducial markers that have been coated with nanoporous polymer matrices loaded with nanoparticles (NPs). In this work, two approaches were studied: (i) a free drug release system consisting of Doxorubicin (Dox), a hydrophilic drug, loaded into a non-degradable polymer poly(methyl methacrylate) (PMMA) coating and (ii) poly(d,l-lactic-co-glycolic acid) (PLGA) NPs loaded with fluorescent Coumarin-6, serving as a model for a hydrophobic drug, in a biodegradable chitosan matrix. Temporal release kinetics measurements in buffer were carried out using fluorescence spectroscopy. In the first case of free Dox release, an initial release within the first few hours was followed by a sustained release over the course of the next 3 months. In the second platform, release of NPs and the free drug was controlled by the degradation rate of the chitosan matrix and PLGA. The results show that dosage and rate of release of these radiosensitizers coated on gold fiducials for IGRT can be precisely tailored to achieve the desired release profile for radiation therapy of cancer.

  5. Toward modeling of radio-frequency ablation lesions for image-guided left atrial fibrillation therapy: model formulation and preliminary evaluation.

    PubMed

    Linte, Cristian A; Camp, Jon J; Holmes, David R; Rettmann, Maryam E; Packer, Douglas L; Robb, Richard A

    2013-01-01

    In the context of image-guided left atrial fibrillation therapy, relatively very little work has been done to consider the changes that occur in the tissue during ablation in order to monitor therapy delivery. Here we describe a technique to predict the lesion progression and monitor the radio-frequency energy delivery via a thermal ablation model that uses heat transfer principles to estimate the tissue temperature distribution and resulting lesion. A preliminary evaluation of the model was conducted in ex vivo skeletal beef muscle tissue while emulating a clinically relevant tissue ablation protocol. The predicted temperature distribution within the tissue was assessed against that measured directly using fiberoptic temperature probes and showed agreement within 5°C between the model-predicted and experimentally measured tissue temperatures at prescribed locations. We believe this technique is capable of providing reasonably accurate representations of the tissue response to radio-frequency energy delivery.

  6. Guy's Guide to Body Image

    MedlinePlus

    ... Healthy Breakfasts Shyness A Guy's Guide to Body Image KidsHealth > For Teens > A Guy's Guide to Body ... image can be a problem. Why Is Body Image Important? Body image is a person's opinions, thoughts, ...

  7. Radio and optical interferometric imaging

    NASA Technical Reports Server (NTRS)

    Cornwell, Tim J.

    1992-01-01

    Since diffraction-limited imaging with a single aperture yields angular resolution approx. lambda/D, the attainment of high angular resolution with single apertures requires the construction of correspondingly large monolithic apertures, the whole surface of which must be figured to much less than a wavelength. At the longer wavelengths, it is impossible to build a sufficiently large single aperture: for example, at lambda 21 cm, arcsec resolution requires an aperture of diameter approx. 50 km. At the shorter wavelengths, the atmosphere imposes a natural limit in resolution of about one arcsec. However, another route is possible; that is, using synthetic apertures to image the sky. Synthetic apertures are now in use in many fields, e.g., radio interferometry, radar imaging, and magnetic-resonance imaging. Radio-interferometric techniques developed in radio astronomy over the past 40 years are now being applied to optical and IR astronomical imaging by a number of groups. Furthermore, the problem of figuring synthetic apertures is considerably simpler, and can be implemented in a computer: new 'self-calibration' techniques allow imaging even in the presence of phase errors due to the atmosphere.

  8. Radio and optical interferometric imaging

    NASA Astrophysics Data System (ADS)

    Cornwell, Tim J.

    1992-11-01

    Since diffraction-limited imaging with a single aperture yields angular resolution approx. lambda/D, the attainment of high angular resolution with single apertures requires the construction of correspondingly large monolithic apertures, the whole surface of which must be figured to much less than a wavelength. At the longer wavelengths, it is impossible to build a sufficiently large single aperture: for example, at lambda 21 cm, arcsec resolution requires an aperture of diameter approx. 50 km. At the shorter wavelengths, the atmosphere imposes a natural limit in resolution of about one arcsec. However, another route is possible; that is, using synthetic apertures to image the sky. Synthetic apertures are now in use in many fields, e.g., radio interferometry, radar imaging, and magnetic-resonance imaging. Radio-interferometric techniques developed in radio astronomy over the past 40 years are now being applied to optical and IR astronomical imaging by a number of groups. Furthermore, the problem of figuring synthetic apertures is considerably simpler, and can be implemented in a computer: new 'self-calibration' techniques allow imaging even in the presence of phase errors due to the atmosphere.

  9. An overview and guide: planning instructional radio.

    PubMed

    Imhoof, M

    1984-03-01

    Successful instructional radio projects require both comprehensive and complex planning. The instructional radio planning team needs to have knowledge and capabilities in several technical, social, and educational areas. Among other skills, the team must understand radio, curriculum design, the subject matter being taught, research and evaluation, and the environment in which the project operates. Once a basic approach to educational planning has been selected and broad educational goals set, radio may be selected as a cost effective means of achieving some of the goals. Assuming radio is a wise choice, there are still several factors which must be analyzed by a team member who is a radio specialist. The most obvious consideration is the inventory and evaluation of the facilities: studios; broadcast, recording, and transmission equipment; classroom radios; and so on. Capabilities of broadcast personnel are another consideration. Initial radio lessons need to teach the learners how to listen to the radio if they have no previous experience with institutional radio broadcasts. A captive, inschool audience ready to listen to radio instructions requires a different use of the medium than a noncaptive audience. With the noncaptive audience, the educational broadcaster must compete with entertaining choices from other media and popular activities and pastimes of the community. The most complex knowledge and analysis required in planning instructional radio concerns the relationship of the content to the medium. Environmental factors are important in planning educational programs. The physical environment may present several constraints on the learning experience and the use of radio. The most obvious is the effect of climate and terrain on the quality of radio reception. The physical environment is easily studied through experience in the target area, but this knowledge plays a significant role in designing effective learning materials for specific learners. Social

  10. Radio-guided localization of clinically occult breast lesions: current modalities and future directions.

    PubMed

    Aydogan, Fatih; Velidedeoglu, Mehmet; Kilic, Fahrettin; Yilmaz, Halit

    2014-01-01

    The extensive availability of breast cancer screening programs and improvement in diagnostic imaging have led to more frequent detection of suspicious and clinically occult breast lesions. Early detection of tumor is important for breast-conserving treatment. Incomplete excision is a major risk factor for local recurrence. Following precise localization and removing the entire lesion while achieving adequate clear margins is the key factor for successful management of non-palpable breast lesions. For this purpose, several techniques such as wire-guided localization, intra-operative ultrasound guided resection, radio-guided occult lesion localization and radioactive seed localization have been described and applied. In this article, we overview the two commonly used localization techniques, radio-guided occult lesion localization and wire-guided localization, particularly describing their advantages and drawbacks.

  11. Radio Spectroscopic Imaging of Electron Beams in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Bastian, Timothy S.; Chen, B.

    2012-05-01

    The recently upgraded Jansky Very Large Array was used to observe the radio emission from a C class solar flare. Observations were performed from 1-2 GHz with a spectral resolution of 1 MHz and time resolution of 100 ms. A number of fast-drift, type-III-like radio bursts was observed, the result of nonthermal electron beams propagating from the flare site, guided by the coronal magnetic field. Using these dynamic, imaging, spectroscopic observations, the electron beam trajectories are deduced.Implications are briefly discussed.

  12. Radio imaging of launch vehicles and payloads

    NASA Astrophysics Data System (ADS)

    Rowe, Harrison E.

    1988-01-01

    The detection and tracing of rockets and payloads by microwave or millimeter-wave passive radio temperature measurements is analytically studied using radio astronomical techniques. Radio image reconstruction is performed by spatial filtering of multiple, simultaneous, equally-spaced radio brightness measurements. Both Wiener filtering for complex images and matched filtering for separated, point targets are considered. Output SNR is found to improve as receiver integration time increases, but blurring due to image motion places a limit on receiver integration time with fixed spatial filters. Little difference is found between an antenna with tapered illumination and low sidelobes and a maximum gain antenna with high sidelobes for interpolation. Several numerical examples are presented in order to give a preliminary indication of the magnitudes of system parameters.

  13. Teacher's Guide to the German/American Heritage Radio Series.

    ERIC Educational Resources Information Center

    Hasselriis, Peter

    The guide suggests teaching methods and learning activities related to German Americans and their heritage in Missouri. Intended for upper elementary and secondary ethnic studies or history courses, the material outlines and supports 13 radio programs. The objective is to increase awareness and understanding of the various facets of the German…

  14. Guide to Professional Radio & TV Newscasting.

    ERIC Educational Resources Information Center

    Siller, Robert C.

    Written for those who want to get started in the field of broadcast journalism, this practical self-study guide discusses all the basic elements needed and shows how the professionals on both local and network levels prepare for a newscast. The content encompasses how a newsman writes his copy, how he "plays" his story, and how writing style is…

  15. [Image-guided radiotherapy].

    PubMed

    de Crevoisier, R; Chauvet, B; Barillot, I; Lafond, C; Mahé, M; Delpon, G

    2016-09-01

    The IGRT is described in its various equipment and implementation. IGRT can be based either on ionizing radiation generating 2D imaging (MV or kV) or 3D imaging (CBCT or MV-CT) or on non-ionizing radiation (ultrasound, optical imaging, MRI or radiofrequency). Adaptive radiation therapy is then presented in its principles of implementation. The function of the technicians for IGRT is then presented and the possible dose delivered by the on-board imaging is discussed. The quality control of IGRT devices is finally described.

  16. Image-guided endobronchial ultrasound

    NASA Astrophysics Data System (ADS)

    Higgins, William E.; Zang, Xiaonan; Cheirsilp, Ronnarit; Byrnes, Patrick; Kuhlengel, Trevor; Bascom, Rebecca; Toth, Jennifer

    2016-03-01

    Endobronchial ultrasound (EBUS) is now recommended as a standard procedure for in vivo verification of extraluminal diagnostic sites during cancer-staging bronchoscopy. Yet, physicians vary considerably in their skills at using EBUS effectively. Regarding existing bronchoscopy guidance systems, studies have shown their effectiveness in the lung-cancer management process. With such a system, a patient's X-ray computed tomography (CT) scan is used to plan a procedure to regions of interest (ROIs). This plan is then used during follow-on guided bronchoscopy. Recent clinical guidelines for lung cancer, however, also dictate using positron emission tomography (PET) imaging for identifying suspicious ROIs and aiding in the cancer-staging process. While researchers have attempted to use guided bronchoscopy systems in tandem with PET imaging and EBUS, no true EBUS-centric guidance system exists. We now propose a full multimodal image-based methodology for guiding EBUS. The complete methodology involves two components: 1) a procedure planning protocol that gives bronchoscope movements appropriate for live EBUS positioning; and 2) a guidance strategy and associated system graphical user interface (GUI) designed for image-guided EBUS. We present results demonstrating the operation of the system.

  17. Wide field imaging problems in radio astronomy

    NASA Astrophysics Data System (ADS)

    Cornwell, T. J.; Golap, K.; Bhatnagar, S.

    2005-03-01

    The new generation of synthesis radio telescopes now being proposed, designed, and constructed face substantial problems in making images over wide fields of view. Such observations are required either to achieve the full sensitivity limit in crowded fields or for surveys. The Square Kilometre Array (SKA Consortium, Tech. Rep., 2004), now being developed by an international consortium of 15 countries, will require advances well beyond the current state of the art. We review the theory of synthesis radio telescopes for large fields of view. We describe a new algorithm, W projection, for correcting the non-coplanar baselines aberration. This algorithm has improved performance over those previously used (typically an order of magnitude in speed). Despite the advent of W projection, the computing hardware required for SKA wide field imaging is estimated to cost up to $500M (2015 dollars). This is about half the target cost of the SKA. Reconfigurable computing is one way in which the costs can be decreased dramatically.

  18. Image-guided tissue engineering

    PubMed Central

    Ballyns, Jeffrey J; Bonassar, Lawrence J

    2009-01-01

    Replication of anatomic shape is a significant challenge in developing implants for regenerative medicine. This has lead to significant interest in using medical imaging techniques such as magnetic resonance imaging and computed tomography to design tissue engineered constructs. Implementation of medical imaging and computer aided design in combination with technologies for rapid prototyping of living implants enables the generation of highly reproducible constructs with spatial resolution up to 25 μm. In this paper, we review the medical imaging modalities available and a paradigm for choosing a particular imaging technique. We also present fabrication techniques and methodologies for producing cellular engineered constructs. Finally, we comment on future challenges involved with image guided tissue engineering and efforts to generate engineered constructs ready for implantation. PMID:19583811

  19. Imaging Radio Galaxies with Adaptive Optics

    NASA Astrophysics Data System (ADS)

    de Vries, W. H.; van Breugel, W. J. M.; Quirrenbach, A.; Roberts, J.; Fidkowski, K.

    2000-12-01

    We present 42 milli-arcsecond resolution Adaptive Optics near-infrared images of 3C 452 and 3C 294, two powerful radio galaxies at z=0.081 and z=1.79 respectively, obtained with the NIRSPEC/SCAM+AO instrument on the Keck telescope. The observations provide unprecedented morphological detail of radio galaxy components like nuclear dust-lanes, off-centered or binary nuclei, and merger induced starforming structures; all of which are key features in understanding galaxy formation and the onset of powerful radio emission. Complementary optical HST imaging data are used to construct high resolution color images, which, for the first time, have matching optical and near-IR resolutions. Based on these maps, the extra-nuclear structural morphologies and compositions of both galaxies are discussed. Furthermore, detailed brightness profile analysis of 3C 452 allows a direct comparison to a large literature sample of nearby ellipticals, all of which have been observed in the optical and near-IR by HST. Both the imaging data and the profile information on 3C 452 are consistent with it being a relative diminutive and well-evolved elliptical, in stark contrast to 3C 294 which seems to be in its initial formation throes with an active AGN off-centered from the main body of the galaxy. These results are discussed further within the framework of radio galaxy triggering and the formation of massive ellipticals. The work of WdV and WvB was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. The work at UCSD has been supported by the NSF Science and Technology Center for Adaptive Optics, under agreement No. AST-98-76783.

  20. Magnetic resonance image guided brachytherapy.

    PubMed

    Tanderup, Kari; Viswanathan, Akila N; Kirisits, Christian; Frank, Steven J

    2014-07-01

    The application of magnetic resonance image (MRI)-guided brachytherapy has demonstrated significant growth during the past 2 decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and resulted in mounting evidence of improved clinical outcome regarding local control, overall survival as well as morbidity. MRI-guided prostate high-dose-rate and low-dose-rate brachytherapies have improved the accuracy of target and organs-at-risk delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high-quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education.

  1. Interactive image-guided neurosurgery.

    PubMed

    Galloway, R L; Maciunas, R J; Edwards, C A

    1992-12-01

    Interactive image-guided (IIG) surgery involves the synchronal display of the tip of a surgical device on preoperative scans. This display allows the surgeon to locate the present surgical position relative to the final site of surgical interest. We have developed a technique for IIG surgery device based on a six-degree-of-freedom articulated arm. Design accuracy for the arm is less than 0.1 mm and the present implementation has a submillimetric accuracy. The display can show the surgical position on any tomographic image set with simultaneous display on up to three image sets. Laboratory results and clinical applications are discussed.

  2. Radio Plasma Imager Simulations and Measurements

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Benson, R. F.; Fung, S. F.; Taylor, W. W. L.; Boardsen, S. A.; Reinisch, B. W.; Haines, D. M.; Bibl, K.; Cheney, G.; Galkin, I. A.

    1999-01-01

    The Radio Plasma Imager (RPI) will be the first-of-its kind instrument designed to use radio wave sounding techniques to perform repetitive remote sensing measurements of electron number density (N(sub e)) structures and the dynamics of the magnetosphere and plasmasphere. RPI will fly on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission to be launched early in the year 2000. The design of the RPI is based on recent advances in radio transmitter and receiver design and modern digital processing techniques perfected for ground-based ionospheric sounding over the last two decades. Free-space electromagnetic waves transmitted by the RPI located in the low density magnetospheric cavity will be reflected at distant plasma cutoffs. The location and characteristics of the plasma at those remote reflection points can then be derived from measurements of the echo amplitude, phase, delay time, frequency, polarization, Doppler shift, and echo direction. The 500 m tip-to-tip X and Y (spin plane) antennas and 20 m boom Z axis antenna on RPI will be used to measures echoes coming from distances of several R(sub E).

  3. Characterization of a detector for β^{{-}}_{} radio-guided surgery

    NASA Astrophysics Data System (ADS)

    Russomando, A.; Bellini, F.; Bocci, V.; Collamati, F.; De Lucia, E.; Faccini, R.; Marafini, M.; Mattei, I.; Morganti, S.; Paramatti, R.; Patera, V.; Piersanti, L.; Pinci, D.; Recchia, L.; Sarti, A.; Sciubba, A.; Senzacqua, M.; Solfaroli Camillocci, E.; Voena, C.

    2016-01-01

    This paper reports a new device for the radio-guided surgery technique exploiting β^{{-}}_{} emitters. A specific intraoperative β^{{-}}_{} detecting probe based on a low-density organic crystal, the diphenylbutadiene-doped para-therphenyl, coupled by optical fibres to a photomultiplier, was developed. A portable readout electronics was designed to provide the surgeons with multi real-time feedback. The aspects related to the applicability of the device, in particular the perception of the spatial resolution of the probe and the comprehension time necessary to the operator to interpret the system response were investigated. Preliminary promising results support the possibility of using this innovative probe in cancer surgery.

  4. Radio-guided occult lesion localisation using iodine 125 Seeds “ROLLIS” to guide surgical removal of an impalpable posterior chest wall melanoma metastasis

    SciTech Connect

    Dissanayake, Shashini; Dissanayake, Deepthi; Taylor, Donna B

    2015-09-15

    Cancer screening and surveillance programmes and the use of sophisticated imaging tools such as positron emission tomography-computed tomography (PET-CT) have increased the detection of impalpable lesions requiring imaging guidance for excision. A new technique involves intra-lesional insertion of a low-activity iodine-125 ({sup 125}I) seed and detection of the radioactive signal in theatre using a hand-held gamma probe to guide surgery. Whilst several studies describe using this method to guide the removal of impalpable breast lesions, only a handful of publications report its use to guide excision of lesions outside the breast. We describe a case in which radio-guided occult lesion localisation using an iodine 125 seed was used to guide excision of an impalpable posterior chest wall metastasis detected on PET-CT.

  5. Image-Guided Renal Intervention.

    PubMed

    Frey, Gregory T; Sella, David M; Atwell, Thomas D

    2015-09-01

    The role of interventional radiology in the management of renal malignancy has expanded in the past 2 decades, largely because of the efficacy of image-guided ablation in treating renal cell carcinoma (RCC). Clinical guidelines now incorporate ablation into standardized RCC management algorithms. Importantly, both radiofrequency ablation and cryoablation have shown long-term durability in the definitive treatment of RCC, and early outcomes following microwave ablation are equally promising. While selective renal artery embolization has a role in the palliation of select patients with RCC, it can also be used to minimize complications in the ablation of larger renal masses.

  6. The Radio Plasma Imager Investigation on the IMAGE Spacecraft

    NASA Technical Reports Server (NTRS)

    Reinisch, Bodo W.; Haines, D. M.; Bibl, K.; Cheney, G.; Galkin, I. A.; Huang, X.; Myers, S. H.; Sales, G. S.; Benson, R. F.; Fung, S. F.

    1999-01-01

    Radio plasma imaging uses total reflection of electromagnetic waves from plasmas whose plasma frequencies equal the radio sounding frequency and whose electron density gradients are parallel to the wave normals. The Radio Plasma Imager (RPI) has two orthogonal 500-m long dipole antennas in the spin plane for near omni-directional transmission. The third antenna is a 20-m dipole. Echoes from the magnetopause, plasmasphere and cusp will be received with three orthogonal antennas, allowing the determination of their angle-of-arrival. Thus it will be possible to create image fragments of the reflecting density structures. The instrument can execute a large variety of programmable measuring programs operating at frequencies between 3 kHz and 3 MHz. Tuning of the transmit antennas provides optimum power transfer from the 10 W transmitter to the antennas. The instrument can operate in three active sounding modes: (1) remote sounding to probe magnetospheric boundaries, (2) local (relaxation) sounding to probe the local plasma, and (3) whistler stimulation sounding. In addition, there is a passive mode to record natural emissions, and to determine the local electron density and temperature by using a thermal noise spectroscopy technique.

  7. Appliance Repair; Radio and Television. Trade and Industrial Education Trade Preparatory Training Guide.

    ERIC Educational Resources Information Center

    Nebraska State Dept. of Education, Lincoln. Div. of Vocational Education.

    One of a series of curriculum guides prepared for the electricity/electronics occupations cluster, this guide identifies the essentials of the appliance repair and radio and television trade as recommended by successful servicemen. An instructional program based upon the implementation of the guide is expected to prepare a student to adequately…

  8. Amateur Radio in Space: A Teacher's Guide with Activities in Science, Mathematics, and Technology.

    ERIC Educational Resources Information Center

    Peck, Sandy; White, Rosalie

    This educator's guide contains background information on the Space Amateur Radio EXperiment (SAREX) designed to facilitate communication between astronauts in orbit and students on the ground. Through SAREX, astronauts make scheduled and unscheduled amateur radio contacts from the Shuttle orbiter with schools selected through a proposal process…

  9. Multiscale image fusion through guided filtering

    NASA Astrophysics Data System (ADS)

    Toet, Alexander; Hogervorst, Maarten A.

    2016-10-01

    We introduce a multiscale image fusion scheme based on guided filtering. Guided filtering can effectively reduce noise while preserving detail boundaries. When applied in an iterative mode, guided filtering selectively eliminates small scale details while restoring larger scale edges. The proposed multi-scale image fusion scheme achieves optimal spatial consistency by using guided filtering both at the decomposition and at the recombination stage of the multiscale fusion process. First, size-selective iterative guided filtering is applied to decompose the source images into base and detail layers at multiple levels of resolution. Then, frequency-tuned filtering is used to compute saliency maps at successive levels of resolution. Next, at each resolution level a binary weighting map is obtained as the pixelwise maximum of corresponding source saliency maps. Guided filtering of the binary weighting maps with their corresponding source images as guidance images serves to reduce noise and to restore spatial consistency. The final fused image is obtained as the weighted recombination of the individual detail layers and the mean of the lowest resolution base layers. Application to multiband visual (intensified) and thermal infrared imagery demonstrates that the proposed method obtains state-ofthe- art performance for the fusion of multispectral nightvision images. The method has a simple implementation and is computationally efficient.

  10. Improving Performance During Image-Guided Procedures

    PubMed Central

    Duncan, James R.; Tabriz, David

    2015-01-01

    Objective Image-guided procedures have become a mainstay of modern health care. This article reviews how human operators process imaging data and use it to plan procedures and make intraprocedural decisions. Methods A series of models from human factors research, communication theory, and organizational learning were applied to the human-machine interface that occupies the center stage during image-guided procedures. Results Together, these models suggest several opportunities for improving performance as follows: 1. Performance will depend not only on the operator’s skill but also on the knowledge embedded in the imaging technology, available tools, and existing protocols. 2. Voluntary movements consist of planning and execution phases. Performance subscores should be developed that assess quality and efficiency during each phase. For procedures involving ionizing radiation (fluoroscopy and computed tomography), radiation metrics can be used to assess performance. 3. At a basic level, these procedures consist of advancing a tool to a specific location within a patient and using the tool. Paradigms from mapping and navigation should be applied to image-guided procedures. 4. Recording the content of the imaging system allows one to reconstruct the stimulus/response cycles that occur during image-guided procedures. Conclusions When compared with traditional “open” procedures, the technology used during image-guided procedures places an imaging system and long thin tools between the operator and the patient. Taking a step back and reexamining how information flows through an imaging system and how actions are conveyed through human-machine interfaces suggest that much can be learned from studying system failures. In the same way that flight data recorders revolutionized accident investigations in aviation, much could be learned from recording video data during image-guided procedures. PMID:24921628

  11. An MF/HF radio array for radio and radar imaging of the ionosphere

    NASA Astrophysics Data System (ADS)

    Isham, Brett; Gustavsson, Bjorn; Belyey, Vasyl; Bullett, Terrence

    2016-07-01

    The Aguadilla Radio Array will be installed at the Interamerican University Aguadilla Campus, located in northwestern Puerto Rico. The array is intended for broad-band medium and high-frequency (MF/HF, roughly 2 to 25 MHz) radio and bistatic radar observations of the ionosphere. The main array consists of 20 antenna elements, arranged in a semi-random pattern providing a good distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. A relocatable 6-element array is also being developed, in which each element consists of a crossed pair of active electric dipoles and all associated electronics for phase-coherent radio measurements. A primary scientific goal of the array is to create images of the region of ionospheric radio emissions stimulated by the new Arecibo Observatory high-power high-frequency radio transmitter. A second primary goal is the study of ionospheric structure and dynamics via coherent radar imaging of the ionosphere in collaboration with the University of Colorado / NOAA Versatile Interferometric Pulsed Ionospheric Radar (VIPIR), located at the USGS San Juan Observatory in Cayey, Puerto Rico. In addition to ionospheric research in collaboration with the Cayey and Arecibo Observatories, the goals of the project include the development of radio sounding, polarization, interferometry, and imaging techniques, and training of students at the university and high school levels.

  12. Image-Guided Adrenal and Renal Biopsy

    PubMed Central

    Sharma, Karun V.; Venkatesan, Aradhana M.; Swerdlow, Daniel; DaSilva, Daniel; Beck, Avi; Jain, Nidhi; Wood, Bradford J.

    2010-01-01

    Image-guided biopsy is a safe and well-established technique that is familiar to most interventional radiologists (IRs). Improvements in image-guidance, biopsy tools and biopsy techniques now routinely allow for safe biopsy of renal and adrenal lesions which traditionally were considered difficult to reach or technically challenging. Image-guided biopsy is used to establish the definitive tissue diagnosis in adrenal mass lesions that can not be fully characterized with imaging or laboratory tests alone. It is also used to establish definitive diagnosis in some cases of renal parenchymal disease and has an expanding role in diagnosis and characterization of renal masses prior to treatment. Although basic principles and techniques for image-guided needle biopsy are similar regardless of organ, this paper will highlight some technical considerations, indications and complications which are unique to the adrenal gland and kidney because of their anatomic location and physiologic features. PMID:20540919

  13. Guy's Guide to Body Image

    MedlinePlus

    ... for Parents for Kids for Teens Teens Home Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Q&A School & Jobs Drugs & Alcohol Staying Safe Recipes En Español Making a Change – Your ... KidsHealth > For Teens > A Guy's Guide to ...

  14. Adaptive dispersion compensation for guided wave imaging

    NASA Astrophysics Data System (ADS)

    Hall, James S.; Michaels, Jennifer E.

    2012-05-01

    Ultrasonic guided waves offer the promise of fast and reliable methods for interrogating large, plate-like structures. Distributed arrays of permanently attached, inexpensive piezoelectric transducers have thus been proposed as a cost-effective means to excite and measure ultrasonic guided waves for structural health monitoring (SHM) applications. Guided wave data recorded from a distributed array of transducers are often analyzed and interpreted through the use of guided wave imaging algorithms, such as conventional delay-and-sum imaging or the more recently applied minimum variance imaging. Both imaging algorithms perform reasonably well using signal envelopes, but can exhibit significant performance improvements when phase information is used. However, the use of phase information inherently requires knowledge of the dispersion relations, which are often not known to a sufficient degree of accuracy for high quality imaging since they are very sensitive to environmental conditions such as temperature, pressure, and loading. This work seeks to perform improved imaging with phase information by leveraging adaptive dispersion estimates obtained from in situ measurements. Experimentally obtained data from a distributed array is used to validate the proposed approach.

  15. Guide to Magellan image interpretation

    NASA Technical Reports Server (NTRS)

    Ford, John P.; Plaut, Jeffrey J.; Weitz, Catherine M.; Farr, Tom G.; Senske, David A.; Stofan, Ellen R.; Michaels, Gregory; Parker, Timothy J.; Fulton, D. (Editor)

    1993-01-01

    An overview of Magellan Mission requirements, radar system characteristics, and methods of data collection is followed by a description of the image data, mosaic formats, areal coverage, resolution, and pixel DN-to-dB conversion. The availability and sources of image data are outlined. Applications of the altimeter data to estimate relief, Fresnel reflectivity, and surface slope, and the radiometer data to derive microwave emissivity are summarized and illustrated in conjunction with corresponding SAR image data. Same-side and opposite-side stereo images provide examples of parallax differences from which to measure relief with a lateral resolution many times greater than that of the altimeter. Basic radar interactions with geologic surfaces are discussed with respect to radar-imaging geometry, surface roughness, backscatter modeling, and dielectric constant. Techniques are described for interpreting the geomorphology and surface properties of surficial features, impact craters, tectonically deformed terrain, and volcanic landforms. The morphologic characteristics that distinguish impact craters from volcanic craters are defined. Criteria for discriminating extensional and compressional origins of tectonic features are discussed. Volcanic edifices, constructs, and lava channels are readily identified from their radar outlines in images. Geologic map units are identified on the basis of surface texture, image brightness, pattern, and morphology. Superposition, cross-cutting relations, and areal distribution of the units serve to elucidate the geologic history.

  16. Image quality (IQ) guided multispectral image compression

    NASA Astrophysics Data System (ADS)

    Zheng, Yufeng; Chen, Genshe; Wang, Zhonghai; Blasch, Erik

    2016-05-01

    Image compression is necessary for data transportation, which saves both transferring time and storage space. In this paper, we focus on our discussion on lossy compression. There are many standard image formats and corresponding compression algorithms, for examples, JPEG (DCT -- discrete cosine transform), JPEG 2000 (DWT -- discrete wavelet transform), BPG (better portable graphics) and TIFF (LZW -- Lempel-Ziv-Welch). The image quality (IQ) of decompressed image will be measured by numerical metrics such as root mean square error (RMSE), peak signal-to-noise ratio (PSNR), and structural Similarity (SSIM) Index. Given an image and a specified IQ, we will investigate how to select a compression method and its parameters to achieve an expected compression. Our scenario consists of 3 steps. The first step is to compress a set of interested images by varying parameters and compute their IQs for each compression method. The second step is to create several regression models per compression method after analyzing the IQ-measurement versus compression-parameter from a number of compressed images. The third step is to compress the given image with the specified IQ using the selected compression method (JPEG, JPEG2000, BPG, or TIFF) according to the regressed models. The IQ may be specified by a compression ratio (e.g., 100), then we will select the compression method of the highest IQ (SSIM, or PSNR). Or the IQ may be specified by a IQ metric (e.g., SSIM = 0.8, or PSNR = 50), then we will select the compression method of the highest compression ratio. Our experiments tested on thermal (long-wave infrared) images (in gray scales) showed very promising results.

  17. Green channel guiding denoising on bayer image.

    PubMed

    Tan, Xin; Lai, Shiming; Liu, Yu; Zhang, Maojun

    2014-01-01

    Denoising is an indispensable function for digital cameras. In respect that noise is diffused during the demosaicking, the denoising ought to work directly on bayer data. The difficulty of denoising on bayer image is the interlaced mosaic pattern of red, green, and blue. Guided filter is a novel time efficient explicit filter kernel which can incorporate additional information from the guidance image, but it is still not applied for bayer image. In this work, we observe that the green channel of bayer mode is higher in both sampling rate and Signal-to-Noise Ratio (SNR) than the red and blue ones. Therefore the green channel can be used to guide denoising. This kind of guidance integrates the different color channels together. Experiments on both actual and simulated bayer images indicate that green channel acts well as the guidance signal, and the proposed method is competitive with other popular filter kernel denoising methods.

  18. RESOLVE: A new algorithm for aperture synthesis imaging of extended emission in radio astronomy

    NASA Astrophysics Data System (ADS)

    Junklewitz, H.; Bell, M. R.; Selig, M.; Enßlin, T. A.

    2016-02-01

    We present resolve, a new algorithm for radio aperture synthesis imaging of extended and diffuse emission in total intensity. The algorithm is derived using Bayesian statistical inference techniques, estimating the surface brightness in the sky assuming a priori log-normal statistics. resolve estimates the measured sky brightness in total intensity, and the spatial correlation structure in the sky, which is used to guide the algorithm to an optimal reconstruction of extended and diffuse sources. During this process, the algorithm succeeds in deconvolving the effects of the radio interferometric point spread function. Additionally, resolve provides a map with an uncertainty estimate of the reconstructed surface brightness. Furthermore, with resolve we introduce a new, optimal visibility weighting scheme that can be viewed as an extension to robust weighting. In tests using simulated observations, the algorithm shows improved performance against two standard imaging approaches for extended sources, Multiscale-CLEAN and the Maximum Entropy Method.

  19. Transverse mode imaging of guided matter waves

    SciTech Connect

    Dall, R. G.; Hodgman, S. S.; Johnsson, M. T.; Baldwin, K. G. H.; Truscott, A. G.

    2010-01-15

    Ultracold atoms whose de Broglie wavelength is of the same order as an extended confining potential can experience waveguiding along the potential. When the transverse kinetic energy of the atoms is sufficiently low, they can be guided in the lowest order mode of the confining potential by analogy with light guided by a single mode optical fiber. We have obtained the first images of the transverse mode structure of guided matter waves in a confining potential with up to 65% of atoms in the lowest order mode. The coherence of the guided atomic de Broglie waves is demonstrated by the diffraction pattern produced when incident upon a two dimensional periodic structure. Such coherent waveguides will be important atom optic components in devices with applications such as atom holography and atom interferometry.

  20. Alignments of radio galaxies in deep radio imaging of ELAIS N1

    NASA Astrophysics Data System (ADS)

    Taylor, A. R.; Jagannathan, P.

    2016-06-01

    We present a study of the distribution of radio jet position angles of radio galaxies over an area of 1 square degree in the ELAIS N1 field. ELAIS N1 was observed with the Giant Metrewave Radio Telescope at 612 MHz to an rms noise level of 10 μJy and angular resolution of 6 arcsec × 5 arcsec. The image contains 65 resolved radio galaxy jets. The spatial distribution reveals a prominent alignment of jet position angles along a `filament' of about 1°. We examine the possibility that the apparent alignment arises from an underlying random distribution and find that the probability of chance alignment is less than 0.1 per cent. An angular covariance analysis of the data indicates the presence of spatially coherence in position angles on scales >0 .^{circ}5. This angular scales translates to a comoving scale of >20 Mpc at a redshift of 1. The implied alignment of the spin axes of massive black holes that give rise to the radio jets suggest the presence of large-scale spatial coherence in angular momentum. Our results reinforce prior evidence for large-scale spatial alignments of quasar optical polarization position angles.

  1. A high-resolution radio image of a young supernova

    NASA Technical Reports Server (NTRS)

    Bartel, N.; Rupen, M. P.; Shapiro, I. I.; Preston, R. A.; Rius, A.

    1991-01-01

    A VLBI radio images of the bright supernova 1986J, which occurred in the galaxy NGC891 at a distance of about 12 Mpc, is presented. No detailed image of any supernova or remnant has been obtained before so soon after the explosion. The image shows a shell of emission with jetlike protrusions. Analysis of the images should advance understanding of the dynamics of the expanding debris, the dissipation of energy into the surrounding circumstellar medium, and the evolution of the supernova into the remnant.

  2. Astronomers Make First Images With Space Radio Telescope

    NASA Astrophysics Data System (ADS)

    1997-07-01

    Marking an important new milestone in radio astronomy history, scientists at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, have made the first images using a radio telescope antenna in space. The images, more than a million times more detailed than those produced by the human eye, used the new Japanese HALCA satellite, working in conjunction with the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and Very Large Array (VLA) ground-based radio telescopes. The landmark images are the result of a long-term NRAO effort supported by the National Aeronautics and Space Administration (NASA). "This success means that our ability to make detailed radio images of objects in the universe is no longer limited by the size of the Earth," said NRAO Director Paul Vanden Bout. "Astronomy's vision has just become much sharper." HALCA, launched on Feb. 11 by Japan's Institute of Space and Astronautical Science (ISAS), is the first satellite designed for radio astronomy imaging. It is part of an international collaboration led by ISAS and backed by NRAO; Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL); the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. On May 22, HALCA observed a distant active galaxy called PKS 1519-273, while the VLBA and VLA also observed it. Data from the satellite was received by a tracking station at the NRAO facility in Green Bank, West Virginia. Tape-recorded data from the satellite and from the radio telescopes on the ground were sent to NRAO's Array Operations Center (AOC) in Socorro, NM. In Socorro, astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope. This dedicated machine, the VLBA Correlator, built as

  3. Image analysis: a consumer's guide.

    PubMed

    Meyer, F

    1983-01-01

    The last years have seen an explosion of systems in image analysis. It is hard for the pathologist or the cytologist to make the right choice of equipment. All machines are stupid, and the only valuable thing is the human work put into it. So make your benefit of the work other people have done for you. Chose a method largely used on many systems and which has proved fertile in many domains and not only for your specific to day's application: Mathematical Morphology, to which are to be added the linear convolutions present on all machines is a strong candidate for becoming such a method. The paper illustrates a working day of an ideal system: research and diagnostic directed work during the working hours, automatic screening of cervical (or other) smears during night.

  4. Comprehensive approach to image-guided surgery

    NASA Astrophysics Data System (ADS)

    Peters, Terence M.; Comeau, Roch M.; Kasrai, Reza; St. Jean, Philippe; Clonda, Diego; Sinasac, M.; Audette, Michel A.; Fenster, Aaron

    1998-06-01

    Image-guided surgery has evolved over the past 15 years from stereotactic planning, where the surgeon planned approaches to intracranial targets on the basis of 2D images presented on a simple workstation, to the use of sophisticated multi- modality 3D image integration in the operating room, with guidance being provided by mechanically, optically or electro-magnetically tracked probes or microscopes. In addition, sophisticated procedures such as thalamotomies and pallidotomies to relieve the symptoms of Parkinson's disease, are performed with the aid of volumetric atlases integrated with the 3D image data. Operations that are performed stereotactically, that is to say via a small burr- hole in the skull, are able to assume that the information contained in the pre-operative imaging study, accurately represents the brain morphology during the surgical procedure. On the other hand, preforming a procedure via an open craniotomy presents a problem. Not only does tissue shift when the operation begins, even the act of opening the skull can cause significant shift of the brain tissue due to the relief of intra-cranial pressure, or the effect of drugs. Means of tracking and correcting such shifts from an important part of the work in the field of image-guided surgery today. One approach has ben through the development of intra-operative MRI imaging systems. We describe an alternative approach which integrates intra-operative ultrasound with pre-operative MRI to track such changes in tissue morphology.

  5. Review of image-guided radiation therapy.

    PubMed

    Jaffray, David; Kupelian, Patrick; Djemil, Toufik; Macklis, Roger M

    2007-01-01

    Image-guided radiation therapy represents a new paradigm in the field of high-precision radiation medicine. A synthesis of recent technological advances in medical imaging and conformal radiation therapy, image-guided radiation therapy represents a further expansion in the recent push for maximizing targeting capabilities with high-intensity radiation dose deposition limited to the true target structures, while minimizing radiation dose deposited in collateral normal tissues. By improving this targeting discrimination, the therapeutic ratio may be enhanced significantly. The principle behind image-guided radiation therapy relies heavily on the acquisition of serial image datasets using a variety of medical imaging platforms, including computed tomography, ultrasound and magnetic resonance imaging. These anatomic and volumetric image datasets are now being augmented through the addition of functional imaging. The current interest in positron-emitted tomography represents a good example of this sort of functional information now being correlated with anatomic localization. As the sophistication of imaging datasets grows, the precise 3D and 4D positions of the target and normal structures become of great relevance, leading to a recent exploration of real- or near-real-time positional replanning of the radiation treatment localization coordinates. This 'adaptive' radiotherapy explicitly recognizes that both tumors and normal tissues change position in time and space during a multiweek course of treatment, and even within a single treatment fraction. As targets and normal tissues change, the attenuation of radiation beams passing through these structures will also change, thus adding an additional level of imprecision in targeting unless these changes are taken into account. All in all, image-guided radiation therapy can be seen as further progress in the development of minimally invasive highly targeted cytotoxic therapies with the goal of substituting remote

  6. Fermi gamma-ray imaging of a radio galaxy.

    PubMed

    Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cavazzuti, E; Cecchi, C; Celik, O; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Colafrancesco, S; Cominsky, L R; Conrad, J; Costamante, L; Cutini, S; Davis, D S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Finke, J; Focke, W B; Fortin, P; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Georganopoulos, M; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hughes, R E; Jackson, M S; Jóhannesson, G; Johnson, A S; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F-W; Sambruna, R; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Starck, J-L; Stawarz, Ł; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M; Hardcastle, M J; Kazanas, D

    2010-05-07

    The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating from the giant radio lobes of the radio galaxy Centaurus A. The resolved gamma-ray image shows the lobes clearly separated from the central active source. In contrast to all other active galaxies detected so far in high-energy gamma-rays, the lobe flux constitutes a considerable portion (greater than one-half) of the total source emission. The gamma-ray emission from the lobes is interpreted as inverse Compton-scattered relic radiation from the cosmic microwave background, with additional contribution at higher energies from the infrared-to-optical extragalactic background light. These measurements provide gamma-ray constraints on the magnetic field and particle energy content in radio galaxy lobes, as well as a promising method to probe the cosmic relic photon fields.

  7. Astronomers Make "Movie" of Radio Images Showing Supernova Explosion

    NASA Astrophysics Data System (ADS)

    1995-11-01

    Astronomers using an international network of radio telescopes have produced a "movie" showing details of the expansion of debris from an exploding star. Their sequence of images constitutes the best determination yet made of the details of a new supernova remnant, and already has raised new questions about such events. The scientists used radio telescopes in Europe and the United States, including the National Science Foundation's Very Large Array (VLA) and Very Long Baseline Array (VLBA), to make very high- resolution images of Supernova 1993J, which was discovered by a Spanish amateur astronomer on March 28, 1993 in the galaxy M81, some 11 million light-years distant in the constellation Ursa Major. Their results are reported in the December 1 issue of the journal Science. The "movie" is based on five images of the supernova, made during 1993 and 1994. The work was done by: Jon Marcaide and Eduardo Ros of the University of Valencia, Spain; Antxon Alberdi of the Special Laboratory for Astrophysics and Fundamental Physics of Madrid, Spain and the Institute of Astrophysics at Andalucia, Spain; Philip Diamond of the National Radio Astronomy Observatory in Socorro, NM; Irwin Shapiro of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA; Jose-Carlos Guirado, Dayton Jones and Robert Preston of the Jet Propulsion Laboratory in Pasadena, CA; Thomas Krichbaum and Arno Witzel of the Max-Planck Institute for Radioastronomy in Bonn, Germany; Franco Mantovani of the Institute of Radioastronomy in Bologna, Italy; Antonio Rius of the Special Laboratory for Astrophysics and Fundamental Physics of Madrid, Spain and the Center for Advanced Studies at Blanes, Spain; Richard Schilizzi of the Joint Institute for VLBI in Europe and Leiden Observatory in the Netherlands; Corrado Trigilio of the Institute of Radioastronomy in Noto, Italy; and Alan Whitney of the MIT- Haystack Observatory in Massachusetts. The capability to make such high-quality images with widely

  8. The clinician's guide to diagnostic imaging

    SciTech Connect

    Grossman, Z.D.; Ellis, D.A.; Brigham, S.C.

    1983-01-01

    ''Contains accurate and essential information on the imaging work-up of many clinical problems. It is best suited for medical students, house staff, and general practitioners who need a quick and easy basic reference when choosing among the various imaging modalities.'' -Radiology ''A practical manual designed for clinicians at any level....Provides a clear working framework.'' -Lancet ''The clarity of the text...is refreshing...It should be read by both referring physicians and imaging specialists.'' This pocket manual provides clinicians, house officers, and medical students with the first practical guide to the most appropriate, cost-effective use of computed tomography, ultrasound, nuclear medicine, and radiography. For each of 42 medical, surgical, and pediatric problems whose workup depends upon imaging, the text presents a logical, step-by-step imaging sequence, outlining the most direct, least invasive route to a diagnosis.

  9. Stochastic Optics: A Scattering Mitigation Framework for Radio Interferometric Imaging

    NASA Astrophysics Data System (ADS)

    Johnson, Michael D.

    2016-12-01

    Just as turbulence in the Earth’s atmosphere can severely limit the angular resolution of optical telescopes, turbulence in the ionized interstellar medium fundamentally limits the resolution of radio telescopes. We present a scattering mitigation framework for radio imaging with very long baseline interferometry (VLBI) that partially overcomes this limitation. Our framework, “stochastic optics,” derives from a simplification of strong interstellar scattering to separate small-scale (“diffractive”) effects from large-scale (“refractive”) effects, thereby separating deterministic and random contributions to the scattering. Stochastic optics extends traditional synthesis imaging by simultaneously reconstructing an unscattered image and its refractive perturbations. Its advantages over direct imaging come from utilizing the many deterministic properties of the scattering—such as the time-averaged “blurring,” polarization independence, and the deterministic evolution in frequency and time—while still accounting for the stochastic image distortions on large scales. These distortions are identified in the image reconstructions through regularization by their time-averaged power spectrum. Using synthetic data, we show that this framework effectively removes the blurring from diffractive scattering while reducing the spurious image features from refractive scattering. Stochastic optics can provide significant improvements over existing scattering mitigation strategies and is especially promising for imaging the Galactic Center supermassive black hole, Sagittarius A*, with the Global mm-VLBI Array and with the Event Horizon Telescope.

  10. Radio-guided surgery improves outcome of therapeutic excision in non-palpable invasive breast cancer.

    PubMed

    Gallegos Hernandez, J F; Tanis, P J; Deurloo, E E; Nieweg, O E; Th Rutgers, E J; Kroon, B B R; Valdés Olmos, R A

    2004-03-01

    Intratumoral injection of a radiocolloid for lymphatic mapping enables the therapeutic excision of clinically occult breast cancer with the aid of a gamma-ray detection probe. The aim of this study was to determine the success rate of radio-guided tumour excision in addition to a guide wire and to identify factors predicting clear margins. Sixty-five consecutive patients underwent radio-guided tumour excision after intratumoral injection of 99mTc-nanocolloid guided by ultrasound or stereotaxis. A localization wire was inserted after scintigraphy had been performed (group 1). The results were compared with retrospective data from 67 consecutive patients who underwent therapeutic wire-directed excision alone (group 2). Factors predicting clear margins (> or = 1 mm) were determined in a logistic regression model. Adequate margins were obtained in 83% of group 1 and in 64% of group 2 (P = 0.014). The invasive component was incompletely excised in two patients in group 1 and in 14 patients in group 2. Further surgery was performed in four patients in group 1 and in 14 patients in group 2. Factors predictive of clear margins were decreasing pathological tumour diameter (P = 0.035), increasing weight of the specimen (P = 0.046), absence of microcalcifications (P = 0.004) and absence of carcinoma in situ component (P = 0.024). Radio-guided excision was an independent predictor of complete excision of the invasive component (P = 0.012). The application of radio-guided surgery combined with wire localization seems to improve the outcome of therapeutic excision of non-palpable invasive breast cancer compared with wire-directed excision alone.

  11. Electromagnetic induction imaging with a radio-frequency atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Deans, Cameron; Marmugi, Luca; Hussain, Sarah; Renzoni, Ferruccio

    2016-03-01

    We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

  12. Image-guided ablation for hepatocellular carcinoma.

    PubMed

    Lencioni, Riccardo; Crocetti, Laura

    2013-01-01

    Image-guided ablation is accepted as the best therapeutic choice for patients with early-stage hepatocellular carcinoma (HCC) when surgical options-including resection and transplantation-are precluded. The term image-guided tumor ablation is defined as the direct application of chemical substances or sources of energy to a focal tumor in an attempt to achieve eradication or substantial tumor destruction. Over the past 25 years, several methods for local tumor destruction have been developed and clinically tested. Radiofrequency ablation (RFA) has shown superior anticancer effect and greater survival benefit with respect to the seminal percutaneous technique, ethanol injection, in meta-analyses of randomized controlled trials, and is currently established as the standard ablative modality. Nevertheless, novel thermal and nonthermal techniques for tumor ablation-including microwave ablation and irreversible electroporation-seem to have potential to improve the efficacy of RFA and are currently undergoing clinical investigation.

  13. Reliability-guided digital image correlation for image deformation measurement

    SciTech Connect

    Pan Bing

    2009-03-10

    A universally applicable reliability-guided digital image correlation (DIC) method is proposed for reliable image deformation measurement. The zero-mean normalized cross correlation (ZNCC) coefficient is used to identify the reliability of the point computed. The correlation calculation begins with a seed point and is then guided by the ZNCC coefficient. That means the neighbors of the point with the highest ZNCC coefficient in a queue for computed points will be processed first. Thus the calculation path is always along the most reliable direction, and possible error propagation of the conventional DIC method can be avoided. The proposed novel DIC method is universally applicable to the images with shadows, discontinuous areas, and deformation discontinuity. Two image pairs were used to evaluate the performance of the proposed technique, and the successful results clearly demonstrate its robustness and effectiveness.

  14. Improved Image-Guided Laparoscopic Prostatectomy

    DTIC Science & Technology

    2013-07-01

    A.2 Materials and Methods Figure A.1: Ultrasound elastography data collection process using the sextant ap- proach; RF data was acquired in axial...were performed in a systematic sextant approach, similar to that used for image guided biopsies. RF data was acquired in axial planes (from gland’s...base, through mid gland, to apex) on the left and right side of the gland (Figure A.1). The sextant approach was necessary to ensure that the scans

  15. An 11-channel radio frequency phased array coil for magnetic resonance guided high-intensity focused ultrasound of the breast.

    PubMed

    Minalga, E; Payne, A; Merrill, R; Todd, N; Vijayakumar, S; Kholmovski, E; Parker, D L; Hadley, J R

    2013-01-01

    In this study, a radio frequency phased array coil was built to image the breast in conjunction with a magnetic resonance guided high-intensity focused ultrasound (MRgHIFU) device designed specifically to treat the breast in a treatment cylinder with reduced water volume. The MRgHIFU breast coil was comprised of a 10-channel phased array coil placed around an MRgHIFU treatment cylinder where nearest-neighbor decoupling was achieved with capacitive decoupling in a shared leg. In addition a single loop coil was placed at the chest wall making a total of 11 channels. The radio frequency coil array design presented in this work was chosen based on ease of implementation, increased visualization into the treatment cylinder, image reconstruction speed, temporal resolution, and resulting signal-to-noise ratio profiles. This work presents a dedicated 11-channel coil for imaging of the breast tissue in the MRgHIFU setup without obstruction of the ultrasound beam and, specifically, compares its performance in signal-to-noise, overall imaging time, and temperature measurement accuracy to that of the standard single chest-loop coil typically used in breast MRgHIFU.

  16. Reconstruction of Radio Images of the Sun Obtained by the Siberian Solar Radio Telescope

    NASA Astrophysics Data System (ADS)

    Lesovoy, S. V.

    2002-11-01

    Reconstruction of radio images of the Sun obtained by the Siberian Solar Radio Telescope (SSRT) encounters two main problems. First, since the solar radio images at a wavelength of 5.2 cm have a high contrast, the amplitude-phase distribution in the antenna-feeder section should be known with a very high accuracy. Second, since such images comprise not only bright compact components but also low-contrast diffuse areas, there is a problem of deconvolution of these diffuse sources, which is inherent to the CLEAN algorithm. To solve the first problem, we determine the amplitude-phase distortions by an iterative analysis of the image itself, in which the opposite sidelobes of the point-source response are compared. To suppress the influence of other sources on the response, we analyze several compact sources. The phase distortions are determined from the asymmetry of the sidelobes, and the amplitude distortions, from sidelobe values. The image is corrected in the spatial-spectrum domain after each iteration. On the one hand, the problems encountered when reconstructing extended sources are related to the fact that the CLEAN algorithm requires significant computer resources. On the other hand, reconstructing images of extended areas requires that the number of cycles of this algorithm should be increased. Another problem consists in the fact that the use of the same ``clean'' antenna pattern for reconstructing compact and extended sources results in appearance of high-frequency distortions of the latter sources. If the CLEAN algorithm is applied, then the computer resources are mainly spent to shift the pattern and to find the maximum of the initial image. We decrease the time necessary for shifting the pattern by excluding the points near the zero value from the antenna-pattern data set and by sorting the remaining data points. The time of finding the maximum was decreased by using a local search window. In addition, we use a number of cutoff levels and search the next

  17. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Hashimoto, Kozo; Boardsen, Scott A.; Garcia, Leonard N.; Green, James L.; Matsumoto, Hiroshi; Reinisch, Bodo W.

    2010-01-01

    We report IMAGE and Geotail simultaneous observations of a terrestrial myriametric radio burst (TMRB) detected on August 19, 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50 kHz), suggesting a fan beam-like emission pattern from a single discrete source. Analysis and comparisons with existing TMR radiations strongly suggest that the TMRB is a distinct emission perhaps resulting from dayside magnetic reconnection instigated by northward interplanetary field condition.

  18. Dynamic targeting image-guided radiotherapy

    SciTech Connect

    Huntzinger, Calvin; Munro, Peter; Johnson, Scott; Miettinen, Mika; Zankowski, Corey; Ahlstrom, Greg; Glettig, Reto; Filliberti, Reto; Kaissl, Wolfgang; Kamber, Martin; Amstutz, Martin; Bouchet, Lionel; Klebanov, Dan; Mostafavi, Hassan; Stark, Richard

    2006-07-01

    Volumetric imaging and planning for 3-dimensional (3D) conformal radiotherapy and intensity-modulated radiotherapy (IMRT) have highlighted the need to the oncology community to better understand the geometric uncertainties inherent in the radiotherapy delivery process, including setup error (interfraction) as well as organ motion during treatment (intrafraction). This has ushered in the development of emerging technologies and clinical processes, collectively referred to as image-guided radiotherapy (IGRT). The goal of IGRT is to provide the tools needed to manage both inter- and intrafraction motion to improve the accuracy of treatment delivery. Like IMRT, IGRT is a process involving all steps in the radiotherapy treatment process, including patient immobilization, computed tomogaphy (CT) simulation, treatment planning, plan verification, patient setup verification and correction, delivery, and quality assurance. The technology and capability of the Dynamic Targeting{sup TM} IGRT system developed by Varian Medical Systems is presented. The core of this system is a Clinac (registered) or Trilogy{sup TM} accelerator equipped with a gantry-mounted imaging system known as the On-Board Imager{sup TM} (OBI). This includes a kilovoltage (kV) x-ray source, an amorphous silicon kV digital image detector, and 2 robotic arms that independently position the kV source and imager orthogonal to the treatment beam. A similar robotic arm positions the PortalVision{sup TM} megavoltage (MV) portal digital image detector, allowing both to be used in concert. The system is designed to support a variety of imaging modalities. The following applications and how they fit in the overall clinical process are described: kV and MV planar radiographic imaging for patient repositioning, kV volumetric cone beam CT imaging for patient repositioning, and kV planar fluoroscopic imaging for gating verification. Achieving image-guided motion management throughout the radiation oncology process

  19. First Radio Burst Imaging Observation From Mingantu Ultrawide Spectral Radioheliograph

    NASA Astrophysics Data System (ADS)

    Yan, Yihua; Chen, Linjie; Yu, Sijie; CSRH Team

    2015-08-01

    Radio imaging spectroscopy over wide range wavelength in dm/cm-bands will open new windows on solar flares and coronal mass ejections by tracing the radio emissions from accelerated electrons. The Chinese Spectral Radioheliograph (CSRH) with two arrays in 400MHz-2GHz /2-15GHz ranges with 64/532 frequency channels have been established in Mingantu Observing Station, Inner Mongolia of China, since 2013 and is in test observations now. CSRH is renamed as MUSER (Mingantu Ultrawide SpEctral Radioheliograph) after it's accomplishment We will introduce the progress and current status of CSRH. Some preliminary results of CSRH will be presented.On 11 Nov2014, the first burst event was registered by MUSER-I array at 400MHz-2GHz waveband. According to SGD event list there was a C-class flare peaked at 04:49UT in the disk center and the radio bursts around 04:22-04:24UT was attributed to this flare. However, MUSER-I image observation of the burst indicates that the radio burst peaked around 04:22UT was due to the eruption at the east limb of the Sun and connected to a CME appeared in that direction about 1 hour later. This demonstrate the importance of the spectroscopy observation of the solar radio burst.Acknowledgement: The CSRH team includes Wei Wang, Zhijun Chen, Fei Liu, Lihong Geng and Jian Zhang and CSRH project is supported by National Major Scientific Equipment R&D Project ZDYZ2009-3. The research was also supported by NSFC grants (11433006, 11221063), MOST grant (MOST2011CB811401), CAS Pilot-B Project (XDB09000000) and Marie Curie PIRSES- GA-295272-RADIOSUN.

  20. Innovation in early breast cancer surgery: radio-guided occult lesion localization and sentinel node biopsy.

    PubMed

    Paganelli, G; Veronesi, U

    2002-07-01

    The surgical management of non-palpable breast lesions remains controversial. At the European Institute of Oncology we have introduced a new technique, radio-guided occult lesion localization (ROLL) to replace standard methods and overcome their disadvantages. Regarding axillary dissection, probe-guided biopsy of the sentinel node (SN) is easy to apply, and the whole procedure is associated to a low risk of false negatives. We suggest that the SN technique should be widely adopted to stage the axilla in patients with breast cancer with clinically negative lymph nodes. Large-scale implementation of the sentinel node technique will reduce the cost of treatment as a result of shorter hospitalization times.

  1. Parameterized Deconvolution for Wide-Band Radio Synthesis Imaging

    NASA Astrophysics Data System (ADS)

    Venkata, Urvashi Rao

    2010-05-01

    The introduction of broad-band receivers into radio interferometry has opened up new opportunities for the study of wide-band continuum emission from a vast range of astrophysical objects. To take full advantage of such instruments and achieve continuum sensitivities, we need image reconstruction algorithms that are sensitive to the frequency dependence of the instrument as well as the spectral structure of the sky brightness distribution. This dissertation project involved a study of existing methods to deal with wideband effects during interferometric image reconstruction, followed by the development of a multi-scale, multi-frequency, synthesis-imaging algorithm (MS-MFS) that (a) takes advantage of the multi-frequency uv-coverage while reconstructing both spatial and spectral structure for compact, extended and moderately resolved sources, (b) constructs intensity, spectral-index and spectral-curvature maps at an angular resolution given by the highest frequency in the band, and (c) corrects for the frequency dependence of the antenna primary beam to enable wide-band imaging across wide fields of view. The MS-MFS algorithm has been implemented in the CASA and ASKAPsoft data-analysis packages, and validated through a series of feasibility tests. This algorithm was then applied to multi-frequency VLA observations of the M87 radio galaxy to derive a 1.1 - 1.8 GHz spectral-index map to complement existing high-angular-resolution low-frequency images. The resulting 75 MHz to 1.8 GHz spectra were compared with models predicted by two different spectral evolution models, and synchrotron lifetimes for various halo features were estimated and interpreted in the context of the dynamical evolution of structures in the M87 radio halo.

  2. A solar type II radio burst from coronal mass ejection-coronal ray interaction: Simultaneous radio and extreme ultraviolet imaging

    SciTech Connect

    Chen, Yao; Du, Guohui; Feng, Shiwei; Kong, Xiangliang; Wang, Bing; Feng, Li; Guo, Fan; Li, Gang

    2014-05-20

    Simultaneous radio and extreme ultraviolet (EUV)/white-light imaging data are examined for a solar type II radio burst occurring on 2010 March 18 to deduce its source location. Using a bow-shock model, we reconstruct the three-dimensional EUV wave front (presumably the type-II-emitting shock) based on the imaging data of the two Solar TErrestrial RElations Observatory spacecraft. It is then combined with the Nançay radio imaging data to infer the three-dimensional position of the type II source. It is found that the type II source coincides with the interface between the coronal mass ejection (CME) EUV wave front and a nearby coronal ray structure, providing evidence that the type II emission is physically related to the CME-ray interaction. This result, consistent with those of previous studies, is based on simultaneous radio and EUV imaging data for the first time.

  3. MILLISECOND IMAGING OF RADIO TRANSIENTS WITH THE POCKET CORRELATOR

    SciTech Connect

    Law, C. J.; Backer, D. C.; Bower, G. C.; Gutierrez-Kraybill, C.; Williams, P. K. G.; Jones, G.; Barott, W. C.; Werthimer, D. E-mail: jones_gl@caltech.edu

    2011-11-20

    We demonstrate a signal-processing concept for imaging the sky at millisecond rates with radio interferometers. The 'Pocket Correlator' (PoCo) correlates the signals from multiple elements of a radio interferometer fast enough to image brief, dispersed pulses. By the nature of interferometry, a millisecond correlator functions like a large, single-dish telescope, but with improved survey speed, spatial localization, calibration, and interference rejection. To test the concept, we installed PoCo at the Allen Telescope Array (ATA) to search for dispersed pulses from the Crab pulsar, B0329+54, and M31 using total-power, visibility-based, and image-plane techniques. In 1.7 hr of observing, PoCo detected 191 giant pulses from the Crab pulsar brighter than a typical 5{sigma} sensitivity limit of 60 Jy over pulse widths of 3 ms. Roughly 40% of pulses from pulsar B0329+54 were detected by using novel visibility-based techniques. Observations of M31 constrain the rate of pulses brighter than 190 Jy in a three-degree region surrounding the galaxy to <4.3 hr{sup -1}. We calculate the computational demand of various visibility-based pulse search algorithms and demonstrate how compute clusters can help meet this demand. Larger implementations of the fast imaging concept will conduct blind searches for millisecond pulses in our Galaxy and beyond, providing a valuable probe of the interstellar/intergalactic media, discovering new kinds of radio transients, and localizing them to constrain models of their origin.

  4. Nanomedicines for image-guided cancer therapy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zheng, Jinzi

    2016-09-01

    Imaging technologies are being increasingly employed to guide the delivery of cancer therapies with the intent to increase their performance and efficacy. To date, many patients have benefited from image-guided treatments through prolonged survival and improvements in quality of life. Advances in nanomedicine have enabled the development of multifunctional imaging agents that can further increase the performance of image-guided cancer therapy. Specifically, this talk will focus on examples that demonstrate the benefits and application of nanomedicine in the context of image-guide surgery, personalized drug delivery, tracking of cell therapies and high precision radiotherapy delivery.

  5. Assessing image-guided implant surgery in today's clinical practice.

    PubMed

    Norkin, Frederic J; Ganeles, Jeffrey; Zfaz, Samuel; Modares, Alireza

    2013-01-01

    As implant dentistry has progressed, greater emphasis has been placed on natural-looking tooth replacement, minimally invasive techniques, and better cost efficiencies, with implant positioning being guided by the desired prosthetic outcome. Image-guided surgery is a technique that merges preoperative diagnostic imaging with computer-based planning tools to facilitate surgical and restorative plans and procedures. This article discusses the intricacies of guided implant surgery, including 3-dimensional presurgical planning and the challenges of maintaining guide stability during surgical execution.

  6. Imaging the Photoevaporating Disk and Radio Jet of GM Aur

    NASA Astrophysics Data System (ADS)

    Macías, Enrique; Anglada, Guillem; Osorio, Mayra; Calvet, Nuria; Torrelles, José M.; Gómez, José F.; Espaillat, Catherine; Lizano, Susana; Rodríguez, Luis F.; Carrasco-González, Carlos; Zapata, Luis

    2016-09-01

    Photoevaporation is probably the main agent for gas dispersal during the last stages of protoplanetary disk evolution. However, the overall mass-loss rate in the photoevaporative wind and its driving mechanism are still not well understood. Here we report multi-configuration Very Large Array observations at 0.7, 3, and 5 cm toward the transitional disk of GM Aur. Our radio continuum observations allow us to image and spatially resolve, for the first time, the three main components at work in this stage of the disk evolution: the disk of dust, the ionized radio jet perpendicular to it, and the photoevaporative wind arising from the disk. The mass-loss rate inferred from the flux density of the radio jet is consistent with the ratio between ejection and accretion rates found in younger objects, suggesting that transitional disks can power collimated ejections of material apparently following the same physical mechanisms as much younger protostars. Our results indicate that extreme-UV (EUV) radiation is the main ionizing mechanism of the photoevaporative wind traced by the free-free emission. The required low EUV photon luminosity of ˜6 × 1040 s-1 would produce a photoevaporation rate of only {\\dot{M}}w,{EUV}≃ 1.3× {10}-10 {M}⊙ yr-1. Therefore, other mechanisms are required to disperse the disk in the timescale imposed by observations.

  7. A test of magnetospheric radio tomographic imaging with IMAGE and WIND

    NASA Astrophysics Data System (ADS)

    Cummer, S. A.; Reiner, M. J.; Reinisch, B. W.; Kaiser, M. L.; Green, J. L.; Benson, R. F.; Manning, R.; Goetz, K.

    Theoretical studies have shown the potential scientific value of multi-spacecraft radio tomographic imaging of the magnetosphere. The <10 RE WIND perigee passes during August 2000 afforded a unique opportunity to test and verify the capabilities of radio tomography by measuring interspacecraft electromagnetic wave propagation parameters using the Radio Plasma Imager (RPI) on IMAGE as the transmitter and the WAVES instrument on WIND as the receiver. The primary goal of this experiment was to measure Faraday rotation variations in the RPI signal and interpret them in terms of the path-integrated magnetic field and electron density. A special 6 W linearly-polarized 828 kHz RPI signal was clearly detected by WAVES more than 6 RE away and showed a distinct signature of time-varying Faraday rotation. We show how changes in the path-integrated electron density/magnetic field product can be unambiguously measured from this continuous, low signal to noise ratio, single frequency measurement.

  8. Near infrared fluorescence for image-guided surgery

    PubMed Central

    2012-01-01

    Near infrared (NIR) image-guided surgery holds great promise for improved surgical outcomes. A number of NIR image-guided surgical systems are currently in preclinical and clinical development with a few approved for limited clinical use. In order to wield the full power of NIR image-guided surgery, clinically available tissue and disease specific NIR fluorophores with high signal to background ratio are necessary. In the current review, the status of NIR image-guided surgery is discussed along with the desired chemical and biological properties of NIR fluorophores. Lastly, tissue and disease targeting strategies for NIR fluorophores are reviewed. PMID:23256079

  9. An EW technology research of jamming IR imaging guided missiles

    NASA Astrophysics Data System (ADS)

    Wu, Xiu-qin; Rong, Hua; Liang, Jing-ping; Chen, Qi; Chen, Min-rong

    2009-07-01

    The IR-Imaging-Guided Weapons have been playing an important role in the modern warfare by means of select attacking the vital parts of targets with the features of highly secret attacking, high precision, and excellent anti-jamming capability ,therefore, they are viewed to be one of the promising precisely guided weapons ,receiving great concern through out the world. This paper discusses the characteristics of IR-Imaging guidance systems at the highlight of making a study of correlated technologies of jamming IR-Imaging-Guided Weapons on the basis of elaborating the operational principles of IR-Imaging-guided Weapons.

  10. Magnetic resonance imaging for image-guided implantology

    NASA Astrophysics Data System (ADS)

    Eggers, Georg; Kress, Bodo; Fiebach, Jochen; Rieker, Marcus; Spitzenberg, Doreen; Marmulla, Rüdiger; Dickhaus, Hartmut; Mühling, Joachim

    2006-03-01

    Image guided implantology using navigation systems is more accurate than manual dental implant insertion. The underlying image data are usually derived from computer tomography. The suitability of MR imaging for dental implant planning is a marginal issue so far. MRI data from cadaver heads were acquired using various MRI sequences. The data were assessed for the quality of anatomical imaging, geometric accuracy and susceptibility to dental metal artefacts. For dental implant planning, 3D models of the jaws were created. A software system for segmentation of the mandible and maxilla MRI data was implemented using c++, mitk, and qt. With the VIBE_15 sequence, image data with high geometric accuracy were acquired. Dental metal artefacts were lower than in CT data of the same heads. The segmentation of the jaws was feasible, in contrast to the segmentation of the dentition, since there is a lack of contrast to the intraoral soft tissue structures. MRI is a suitable method for imaging of the region of mouth and jaws. The geometric accuracy is excellent and the susceptibility to artefacts is low. However, there are yet two limitations: Firstly, the imaging of the dentition needs further improvement to allow accurate segmentation of these regions. Secondly, the sequence used in this study takes several minutes and hence is susceptible to motion artefacts.

  11. Automated landmark-guided deformable image registration.

    PubMed

    Kearney, Vasant; Chen, Susie; Gu, Xuejun; Chiu, Tsuicheng; Liu, Honghuan; Jiang, Lan; Wang, Jing; Yordy, John; Nedzi, Lucien; Mao, Weihua

    2015-01-07

    The purpose of this work is to develop an automated landmark-guided deformable image registration (LDIR) algorithm between the planning CT and daily cone-beam CT (CBCT) with low image quality. This method uses an automated landmark generation algorithm in conjunction with a local small volume gradient matching search engine to map corresponding landmarks between the CBCT and the planning CT. The landmarks act as stabilizing control points in the following Demons deformable image registration. LDIR is implemented on graphics processing units (GPUs) for parallel computation to achieve ultra fast calculation. The accuracy of the LDIR algorithm has been evaluated on a synthetic case in the presence of different noise levels and data of six head and neck cancer patients. The results indicate that LDIR performed better than rigid registration, Demons, and intensity corrected Demons for all similarity metrics used. In conclusion, LDIR achieves high accuracy in the presence of multimodality intensity mismatch and CBCT noise contamination, while simultaneously preserving high computational efficiency.

  12. Automated landmark-guided deformable image registration

    NASA Astrophysics Data System (ADS)

    Kearney, Vasant; Chen, Susie; Gu, Xuejun; Chiu, Tsuicheng; Liu, Honghuan; Jiang, Lan; Wang, Jing; Yordy, John; Nedzi, Lucien; Mao, Weihua

    2015-01-01

    The purpose of this work is to develop an automated landmark-guided deformable image registration (LDIR) algorithm between the planning CT and daily cone-beam CT (CBCT) with low image quality. This method uses an automated landmark generation algorithm in conjunction with a local small volume gradient matching search engine to map corresponding landmarks between the CBCT and the planning CT. The landmarks act as stabilizing control points in the following Demons deformable image registration. LDIR is implemented on graphics processing units (GPUs) for parallel computation to achieve ultra fast calculation. The accuracy of the LDIR algorithm has been evaluated on a synthetic case in the presence of different noise levels and data of six head and neck cancer patients. The results indicate that LDIR performed better than rigid registration, Demons, and intensity corrected Demons for all similarity metrics used. In conclusion, LDIR achieves high accuracy in the presence of multimodality intensity mismatch and CBCT noise contamination, while simultaneously preserving high computational efficiency.

  13. [Good practice of image-guided radiotherapy].

    PubMed

    de Crevoisier, R; Créhange, G; Castelli, J; Lafond, C; Delpon, G

    2015-10-01

    Image-guided radiotherapy (IGRT) aims to take into account the anatomical variations occurring during the course of radiotherapy, by direct or indirect visualization of the target volume followed by a corrective action. The movements of the target, or at least the set-up errors are corrected by moving the treatment table, corresponding to the simplest and most validated IGRT modality in a standard practice. The deformations of the target volume and organs at risk are however much more common, and unfortunately much more complicated to consider, requiring multiple planning before or during the treatment, corresponding to the adaptive radiotherapy strategies. The planning target volume must be carefully chosen according to these anatomic variations. This article reviews the modalities of IGRT, standard or under evaluation, according to the different tumour sites.

  14. Image-guided ablation of adrenal lesions.

    PubMed

    Yamakado, Koichiro

    2014-06-01

    Although laparoscopic adrenalectomy has remained the standard of care for the treatment for adrenal tumors, percutaneous image-guided ablation therapy, such as chemical ablation, radiofrequency ablation, cryoablation, and microwave ablation, has been shown to be clinically useful in many nonsurgical candidates. Ablation therapy has been used to treat both functioning adenomas and malignant tumors, including primary adrenal carcinoma and metastasis. For patients with functioning adenomas, biochemical and symptomatic improvement is achieved in 96 to 100% after ablation; for patients with malignant adrenal neoplasms, however, the survival benefit from ablation therapy remains unclear, though good initial results have been reported. This article outlines the current role of ablation therapy for adrenal lesions, as well as identifying some of the technical considerations for this procedure.

  15. Deep HST imaging of distant weak radio and field galaxies

    NASA Technical Reports Server (NTRS)

    Windhorst, R. A.; Gordon, J. M.; Pascarelle, S. M.; Schmidtke, P. C.; Keel, W. C.; Burkey, J. M.; Dunlop, J. S.

    1994-01-01

    We present deep Hubble Space Telescope (HST) Wide-Field Camera (WFC) V- and I-band images of three distant weak radio galaxies with z = 0.311-2.390 and seven field galaxies with z = 0.131-0.58. The images were deconvolved with both the Lucy and multiresolution CLEAN methods, which yield a restoring Full Width at Half Maximum (FWHM) of less than or equal to 0.2 sec, (nearly) preserve photons and signal-to-noise ratio at low spatial frequencies, and produce consistent light profiles down to our 2 sigma surface brightness sensitivity limit of V approximately 27.2 and I approximately 25.9 mag/sq arcsec. Multi-component image modeling was used to provide deconvolution-independent estimates of structural parameters for symmetric galaxies. We present 12-band (m(sub 2750) UBVRIgriJHK) photometry for a subset of the galaxies and bootstrap the unknown FOC/48 zero point at 2750 A in three independent ways (yielding m(sub 2750) = 21.34 +/- 0.09 mag for 1.0 e(-)/s). Two radio galaxies with z = 0.311 and 0.528, as well as one field galaxy with z = 0.58, have the colors and spectra of early-type galaxies, and a(exp 1/4)-like light profiles in the HST images. The two at z greater than 0.5 have little or no color gradients in V - I and are likely giant ellipticals, while the z = 0.311 radio galaxy has a dim exponential disk and is likely an S0. Six of the seven field galaxies have light profiles that indicate (small) inner bulges following a(exp 1/4) laws and outer exponential disks, both with little or no color gradients. These are (early-type) spiral galaxies with z = 0.131-0.528. About half have faint companions or bars. One shows lumpy structure, possibly a merger. The compact narrow-line galaxy 53W002 at z = 2.390 has less than or = 30% +/- 10% of its HST V and I flux in the central kiloparsec (due to its weak Active Galactic Nucleus (AGN)). Most of its light (V approximately equal to 23.3) occurs in a symmetric envelope with a regular a(exp 1/4)-like profile of effective

  16. Image-guided therapy: evolution and breakthrough.

    PubMed

    Haigron, Pascal; Dillenseger, Jean-Louis; Luo, Limin; Coatrieux, Jean-Louis

    2010-01-01

    Beyond the advances made in computer-assisted interventions and robotic systems, the demand for more efficient and safer therapies remains challenging. Thus, if it is possible to improve the instrument tracking, steering, and target localization, to miniaturize the sensors and actuators, and to conduct preoperatively planned minimally invasive therapies, we still need new resources to achieve permanent destruction of abnormal tissues or suppression of pathological processes. Most of the physics-based (or energy-based) therapeutic principles at our disposal have been established a long time ago, but their actions on basic cellular and molecular mechanisms are not yet fully understood. They all have a wide spectrum of clinical targets in terms of organs and pathologies, modes of application (external, interstitial, intraluminal, etc.) with advantages and side-effect drawbacks, proven indications, and contraindications. Some of them may still face controversies regarding their outcomes. This short article, mainly focused on tumor destruction, briefly reviews in its first part some of these techniques and sketches the next generation under investigation. The former include radio frequency (RF), high-intensity focused ultrasound (HiFU), microwaves, and cryotherapy, of which all are temperature based. Laser-based approaches [e.g., photodynamic therapy (PDT) at large] are also discussed. Radiotherapy and its variants (hadrontherapy, brachytherapy, Gamma Knife, and CyberKnife) remain, of course, as the reference technique in cancer treatment. The next breakthroughs are examined in the second part of the article. They are based on the close association between imaging agents, drugs, and some stimulation techniques. The ongoing research efforts in that direction show that, if they are still far from clinical applications, strong expectations are made. From the point of view of interventional planning and image guidance, all of them share a lot of concerns.

  17. Percutaneous image-guided ablation of breast tumors: an overview.

    PubMed

    Sag, Alan A; Maybody, Majid; Comstock, Christopher; Solomon, Stephen B

    2014-06-01

    Percutaneous non-surgical image-guided ablation is emerging as an adjunct or alternative to surgery in the management of benign and malignant breast tumors. This review covers the current state of the literature regarding percutaneous image-guided ablation modalities, clinical factors regarding patient selection, and future directions for research.

  18. Image-guided simulation for bioluminescence tomographic imaging

    NASA Astrophysics Data System (ADS)

    Kumar, Durairaj; Cong, Wenxiang; Thiesse, Jacqueline; Nixon, Earl; Meinel, John, Jr.; Cong, Alex; McLennan, Geoffrey; Hoffman, Eric A.; Ming, Jiang; Wang, Ge

    2005-04-01

    Noninvasive imaging of the reporter gene expression based on bioluminescence is playing an important role in the areas of cancer biology, cell biology, and gene therapy. The central problem for the bioluminescence tomography (BLT) we are developing is to reconstruct the underlying bioluminescent source distribution in a small animal using a modality fusion approach. To solve this inversion problem, a mathematical model of the mouse is built from a CT/micro-CT scan, which enables the assignment of optical parameters to various regions in the model. This optical geometrical model is used in the Monte Carlo simulation to calculate the flux distribution on the animal body surface, as a key part of the BLT process. The model development necessitates approximations in surface simplification, and so on. It leads to the model mismatches of different kinds. To overcome such discrepancies, instead of developing a mathematical model, segmented CT images are directly used in our simulation software. While the simulation code is executed, those images that are relevant are assessed according to the location of the propagating photon. Depending upon the segmentation rules including the pixel value range, appropriate optical parameters are selected for statistical sampling of the free path and weight of the photon. In this paper, we report luminescence experiments using a physical mouse phantom to evaluate this image-guided simulation procedure, which suggest both the feasibility and some advantages of this technique over the existing methods.

  19. Terrestrial Myriametric Radio Burst Observed by IMAGE and Geotail Satellites

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Hashimoto, KoZo; Kojima, Hirotsugu; Boardson, Scott A.; Garcia, Leonard N.; Matsumoto, Hiroshi; Green, James L.; Reinisch, Bodo W.

    2013-01-01

    We report the simultaneous detection of a terrestrial myriametric radio burst (TMRB) by IMAGE and Geotail on 19 August 2001. The TMRB was confined in time (0830-1006 UT) and frequency (12-50kHz). Comparisons with all known nonthermal myriametric radiation components reveal that the TMRB might be a distinct radiation with a source that is unrelated to the previously known radiation. Considerations of beaming from spin-modulation analysis and observing satellite and source locations suggest that the TMRB may have a fan beamlike radiation pattern emitted by a discrete, dayside source located along the poleward edge of magnetospheric cusp field lines. TMRB responsiveness to IMF Bz and By orientations suggests that a possible source of the TMRB could be due to dayside magnetic reconnection instigated by northward interplanetary field condition.

  20. PURIFY: a new approach to radio-interferometric imaging

    NASA Astrophysics Data System (ADS)

    Carrillo, R. E.; McEwen, J. D.; Wiaux, Y.

    2014-04-01

    In a recent paper series, the authors have promoted convex optimization algorithms for radio-interferometric imaging in the framework of compressed sensing, which leverages sparsity regularization priors for the associated inverse problem and defines a minimization problem for image reconstruction. This approach was shown, in theory and through simulations in a simple discrete visibility setting, to have the potential to outperform significantly CLEAN and its evolutions. In this work, we leverage the versatility of convex optimization in solving minimization problems to both handle realistic continuous visibilities and offer a highly parallelizable structure paving the way to significant acceleration of the reconstruction and high-dimensional data scalability. The new algorithmic structure promoted relies on the simultaneous-direction method of multipliers (SDMM) and contrasts with the current major-minor cycle structure of CLEAN and its evolutions, which in particular cannot handle the state-of-the-art minimization problems under consideration where neither the regularization term nor the data term are differentiable functions. We release a beta version of an SDMM-based imaging software written in C and dubbed PURIFY (http://basp-group.github.io/purify/) that handles various sparsity priors, including our recent average sparsity approach sparsity averaging reweighted analysis (SARA). We evaluate the performance of different priors through simulations in the continuous visibility setting, confirming the superiority of SARA.

  1. Discrete Method of Images for 3D Radio Propagation Modeling

    NASA Astrophysics Data System (ADS)

    Novak, Roman

    2016-09-01

    Discretization by rasterization is introduced into the method of images (MI) in the context of 3D deterministic radio propagation modeling as a way to exploit spatial coherence of electromagnetic propagation for fine-grained parallelism. Traditional algebraic treatment of bounding regions and surfaces is replaced by computer graphics rendering of 3D reflections and double refractions while building the image tree. The visibility of reception points and surfaces is also resolved by shader programs. The proposed rasterization is shown to be of comparable run time to that of the fundamentally parallel shooting and bouncing rays. The rasterization does not affect the signal evaluation backtracking step, thus preserving its advantage over the brute force ray-tracing methods in terms of accuracy. Moreover, the rendering resolution may be scaled back for a given level of scenario detail with only marginal impact on the image tree size. This allows selection of scene optimized execution parameters for faster execution, giving the method a competitive edge. The proposed variant of MI can be run on any GPU that supports real-time 3D graphics.

  2. Radio Synthesis Imaging - A High Performance Computing and Communications Project

    NASA Astrophysics Data System (ADS)

    Crutcher, Richard M.

    The National Science Foundation has funded a five-year High Performance Computing and Communications project at the National Center for Supercomputing Applications (NCSA) for the direct implementation of several of the computing recommendations of the Astronomy and Astrophysics Survey Committee (the "Bahcall report"). This paper is a summary of the project goals and a progress report. The project will implement a prototype of the next generation of astronomical telescope systems - remotely located telescopes connected by high-speed networks to very high performance, scalable architecture computers and on-line data archives, which are accessed by astronomers over Gbit/sec networks. Specifically, a data link has been installed between the BIMA millimeter-wave synthesis array at Hat Creek, California and NCSA at Urbana, Illinois for real-time transmission of data to NCSA. Data are automatically archived, and may be browsed and retrieved by astronomers using the NCSA Mosaic software. In addition, an on-line digital library of processed images will be established. BIMA data will be processed on a very high performance distributed computing system, with I/O, user interface, and most of the software system running on the NCSA Convex C3880 supercomputer or Silicon Graphics Onyx workstations connected by HiPPI to the high performance, massively parallel Thinking Machines Corporation CM-5. The very computationally intensive algorithms for calibration and imaging of radio synthesis array observations will be optimized for the CM-5 and new algorithms which utilize the massively parallel architecture will be developed. Code running simultaneously on the distributed computers will communicate using the Data Transport Mechanism developed by NCSA. The project will also use the BLANCA Gbit/s testbed network between Urbana and Madison, Wisconsin to connect an Onyx workstation in the University of Wisconsin Astronomy Department to the NCSA CM-5, for development of long

  3. Modeling interaction for image-guided procedures

    NASA Astrophysics Data System (ADS)

    Trevisan, Daniela G.; Vanderdonckt, Jean; Macq, Benoit M. M.; Raftopoulos, Christian

    2003-05-01

    Compared to conventional interfaces, image guided surgery (IGS) interfaces contain a richer variety and more complex objects and interaction types. The main interactive characteristics emering from systems like this is the interaction focus shared between physical space, where the surgeon interacts with the patient using surgical tools, and with the digital world, where the surgeon interacts with the system. This limitation results in two different interfaces likely inconsistent, thereby the interaction discontinuities do break the natuarl workflow forcing the user to switch between the operation modes. Our work addresses these features by focusing on the model, interaction and ergonomic integrity analysis considering the Augmented Reality paradigm applied to IGS procedures and more specifically applied to the Neurosurgery study case. We followed a methodology according to the model-based approach, including new extensions in order to support interaction technologies and to sensure continuity interaction according to the IGS system requirements. As a result, designers may as soon as possible discover errors in the development process and may perform an efficient interface design coherently integrating constraints favoring continuity instead of discrete interaction with possible inconsistencies.

  4. Image-guided facet joint injection

    PubMed Central

    Peh, WCG

    2011-01-01

    Chronic spine pain poses a peculiar diagnostic and therapeutic challenge due to multiple pain sources, overlapping clinical features and nonspecific radiological findings. Facet joint injection is an interventional pain management tool for facet-related spinal pain that can be effectively administered by a radiologist. This technique is the gold standard for identifying facet joints as the source of spinal pain. The major indications for facet injections include strong clinical suspicion of the facet syndrome, focal tenderness over the facet joints, low back pain with normal radiological findings, post-laminectomy syndrome with no evidence of arachnoiditis or recurrent disc disease, and persistent low back pain after spinal fusion. The contraindications are more ancillary, with none being absolute. Like any synovial joint degeneration, inflammation and injury can lead to pain on motion, initiating a vicious cycle of physical deconditioning, irritation of facet innervations and muscle spasm. Image-guided injection of local anesthetic and steroid into or around the facet joint aims to break this vicious cycle and thereby provide pain relief. This outpatient procedure has high diagnostic accuracy, safety and reproducibility but the therapeutic outcome is variable. PMID:21655113

  5. A novel multiwavelength fluorescence image-guided surgery imaging system

    NASA Astrophysics Data System (ADS)

    Volpi, D.; Tullis, I. D. C.; Laios, A.; Pathiraja, P. N. J.; Haldar, K.; Ahmed, A. A.; Vojnovic, B.

    2014-02-01

    We describe the development and performance analysis of two clinical near-infrared fluorescence image-guided surgery (FIGS) devices that aim to overcome some of the limitations of current FIGS systems. The devices operate in a widefield-imaging mode and can work (1) in conjunction with a laparoscope, during minimally invasive surgery, and (2) as a hand-held, open surgery imaging system. In both cases, narrow-band excitation light, delivered at multiple wavelengths, is efficiently combined with white reflectance light. Light is delivered to ~100 cm2 surgical field at 1-2 mW/cm2 for white light and 3-7 mW/cm2 (depending on wavelength) of red - near infrared excitation, at a typical working distance of 350 mm for the hand-held device and 100 mm for the laparoscope. A single, sensitive, miniaturized color camera collects both fluorescence and white reflectance light. The use of a single imager eliminates image alignment and software overlay complexity. A novel filtering and illumination arrangement allows simultaneous detection of white reflectance and fluorescence emission from multiple dyes in real-time. We will present both fluorescence detection sensitivity modeling and practical performance data. We have demonstrated the efficiency and the advantages of the devices both pre-clinically and during live surgery on humans. Both the hand-held and the laparoscopic systems have proved to be reliable and beneficial in an ongoing clinical trial involving sentinel lymph node detection in gynecological cancers. We will show preliminary results using two clinically approved dyes, Methylene blue and indocyanine green. We anticipate that this technology can be integrated and routinely used in a larger variety of surgical procedures.

  6. Radio-frequency energy quantification in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Alon, Leeor

    Mapping of radio frequency (RF) energy deposition has been challenging for 50+ years, especially, when scanning patients in the magnetic resonance imaging (MRI) environment. As result, electromagnetic simulation software is often used for estimating the specific absorption rate (SAR), the rate of RF energy deposition in tissue. The thesis work presents challenges associated with aligning information provided by electromagnetic simulation and MRI experiments. As result of the limitations of simulations, experimental methods for the quantification of SAR were established. A system for quantification of the total RF energy deposition was developed for parallel transmit MRI (a system that uses multiple antennas to excite and image the body). The system is capable of monitoring and predicting channel-by-channel RF energy deposition, whole body SAR and capable of tracking potential hardware failures that occur in the transmit chain and may cause the deposition of excessive energy into patients. Similarly, we demonstrated that local RF power deposition can be mapped and predicted for parallel transmit systems based on a series of MRI temperature mapping acquisitions. Resulting from the work, we developed tools for optimal reconstruction temperature maps from MRI acquisitions. The tools developed for temperature mapping paved the way for utilizing MRI as a diagnostic tool for evaluation of RF/microwave emitting device safety. Quantification of the RF energy was demonstrated for both MRI compatible and non-MRI-compatible devices (such as cell phones), while having the advantage of being noninvasive, of providing millimeter resolution and high accuracy.

  7. Basic characteristics of the radio imaging method for biomedical applications.

    PubMed

    Hieda, I; Nam, K C; Takahashi, A

    2004-06-01

    The radio imaging method (RIM), a technology used practically for geophysical surveys, was applied to biomedical measurements. The characteristics of a subject between a pair of simple loop antennas were measured by using a feeble electromagnetic wave of low frequency. Water distribution inside the human body was expected to be measured, as well as the original method imaged mineral distributions. In geophysical surveys, finer resolution is provided than a wavelength of the electromagnetic wave. This was also expected for biomedical measurements. An acrylic water tank was used as a phantom of the abdominal portion of the human body, and basic measurements were performed with the phantom. The inner tank of the phantom, whose cross section was 6 x 8 cm, was detected by the method when the frequency was 54 MHz or the wavelength was nearly 6 m in free space. The resolution provided by the experiment suggested that the proposed method was effective even if the wavelength was longer than the dimensions of the targeted area. The advantage of the method is simplicity, economy and safety. The authors are looking for specific applications for example, a urination sensor or a vital monitor for in-home care, where the strong points of the method are suitable.

  8. Prospects for optical and radio-wave remote imaging of high latitude exospheric processes

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.

    1992-01-01

    The paper examines the use of optical, radio-wave, and extreme UV imaging to study the distribution of magnetospheric plasma continuously and thereby study magnetospheric global dynamics. Optical imaging of the terrestrial exosphere at FUV and EUV wavelengths is discussed in the light of evidence from recent observational campaigns. Radio imaging of the earth's magnetosphere is shown to provide good instantaneous images of the plasma from beyond 4 earth radii. Optical imaging is examined with respect to the study of other planetary exospheres, and the technique is shown to depend on the ability to do normal incidence optics in the EUV. The Cassini radio-uplink experiment is examined as an example of radio-wave tomography which can provide geometry-based tomographic montages to image the heliosphere and the planetary magnetospheres.

  9. Evaluation of Image-Guided Positioning for Frameless Intracranial Radiosurgery

    SciTech Connect

    Lamba, Michael Breneman, John C.; Warnick, Ronald E.

    2009-07-01

    Purpose: The standard for target alignment and immobilization in intracranial radiosurgery is frame-based alignment and rigid immobilization using a stereotactic head ring. Recent improvements in image-guidance systems have introduced the possibility of image-guided radiosurgery with nonrigid immobilization. We present data on the alignment accuracy and patient stability of a frameless image-guided system. Methods and Materials: Isocenter alignment errors were measured for in vitro studies in an anthropomorphic phantom for both frame-based stereotactic and frameless image-guided alignment. Subsequently, in vivo studies assessed differences between frame-based and image-guided alignment in patients who underwent frame-based intracranial radiosurgery. Finally, intratreatment target stability was determined by image-guided alignment performed before and after image-guided mask immobilized radiosurgery. Results: In vitro hidden target localization errors were comparable for the framed (0.7 {+-} 0.5 mm) and image-guided (0.6 {+-} 0.2 mm) techniques. The in vivo differences in alignment were 0.9 {+-} 0.5 mm (anteroposterior), -0.2 {+-} 0.4 mm (superoinferior), and 0.3 {+-} 0.5 mm (lateral). For in vivo stability tests, the mean distance differed between the pre- and post-treatment positions with mask-immobilized radiosurgery by 0.5 {+-} 0.3 mm. Conclusion: Frame-based and image-guided alignment accuracy in vitro was comparable for the system tested. In vivo tests showed a consistent trend in the difference of alignment in the anteroposterior direction, possibly due to torque to the ring and mounting system with frame-based localization. The mask system as used appeared adequate for patient immobilization.

  10. Automated exploration of the radio plasma imager data

    NASA Astrophysics Data System (ADS)

    Galkin, Ivan; Reinisch, Bodo; Grinstein, Georges; Khmyrov, Grigori; Kozlov, Alexander; Huang, Xueqin; Fung, Shing

    2004-12-01

    As research instruments with large information capacities become a reality, automated systems for intelligent data analysis become a necessity. Scientific archives containing huge volumes of data preclude manual manipulation or intervention and require automated exploration and mining that can at least preclassify information in categories. The large data set from the radio plasma imager (RPI) instrument on board the IMAGE satellite shows a critical need for such exploration in order to identify and archive features of interest in the volumes of visual information. In this research we have developed such a preclassifier through a model of preattentive vision capable of detecting and extracting traces of echoes from the RPI plasmagrams. The overall design of our model complies with Marr's paradigm of vision, where elements of increasing perceptual strength are built bottom up under the Gestalt constraints of good continuation and smoothness. The specifics of the RPI data, however, demanded extension of this paradigm to achieve greater robustness for signature analysis. Our preattentive model now employs a feedback neural network that refines alignment of the oriented edge elements (edgels) detected in the plasmagram image by subjecting them to collective global-scale optimization. The level of interaction between the oriented edgels is determined by their distance and mutual orientation in accordance with the Yen and Finkel model of the striate cortex that encompasses findings in psychophysical studies of human vision. The developed models have been implemented in an operational system "CORPRAL" (Cognitive Online RPI Plasmagram Ranking Algorithm) that currently scans daily submissions of the RPI plasmagrams for the presence of echo traces. Qualifying plasmagrams are tagged in the mission database, making them available for a variety of queries. We discuss CORPRAL performance and its impact on scientific analysis of RPI data.

  11. Reflection-contrast limit of fiber-optic image guides

    PubMed Central

    Lane, Pierre M.; MacAulay, Calum E.

    2009-01-01

    Fiber-optic image guides in confocal reflectance endomicroscopes introduce background backscatter that limits the achievable contrast in these devices. We show the dominant source of backscatter from the image guide is due to Rayleigh scattering at short wavelengths and terminal reflections of the fibers at long wavelengths. The effective Rayleigh scattering coefficient and the wavelength-independent reflectivity due terminal reflections are measured experimentally in a commercial image guide. The Rayleigh scattering component of backscatter can be accurately predicted using the fractional refractive-index difference and length of the fibers in the image guide. We also presented a simple model that can be used to predict signal-to-background ratio in a fiber-optic confocal reflectance endomicroscope for biologically relevant tissues and contrast agents that cover a wide range of reflectivity. PMID:20059266

  12. Percutaneous image-guided biopsy of the musculoskeletal system.

    PubMed

    Welch, Brian T; Welch, Timothy J

    2011-09-01

    Percutaneous image-guided biopsy plays an important role in the management of multiple pathologic conditions involving the musculoskeletal system. The vast majority of these conditions require histologic diagnosis to guide decision making concerning treatment. Percutaneous image-guided biopsy has supplanted open surgical biopsy as the primary modality for tissue diagnosis in this patient cohort. The safety, efficacy, and clinical outcome of percutaneous image-guided biopsy for a multitude of musculoskeletal conditions are well documented. Improvements in needle design and image guidance have continued to further the efficacy and safety of this diagnostic technique. Complications associated with percutaneous biopsy are minimal compared with those seen in open surgical biopsy, whereas diagnostic accuracy is comparable to that of surgical biopsy.

  13. An Intraoperative beta (-) Detecting Probe for Radio-Guided Surgery in Tumour Resection

    NASA Astrophysics Data System (ADS)

    Russomando, Andrea; Bellini, Fabio; Bocci, Valerio; Collamati, Francesco; De Lucia, Erika; Faccini, Riccardo; Marafini, Michela; Mattei, Ilaria; Chiodi, Giacomo; Patera, Vincenzo; Recchia, Luigi; Sarti, Alessio; Sciubba, Adalberto; Solfaroli Camillocci, Elena; Paramatti, Riccardo; Voena, Cecilia; Donnarumma, Raffaella; Mancini-Terracciano, Carlo; Morganti, Silvio

    2016-10-01

    The development of the $\\beta^-$ based radio-guided surgery aims to extend the technique to those tumours where surgery is the only possible treatment and the assessment of the resection would most profit from the low background around the lesion, as for brain tumours. Feasibility studies on meningioma, glioma, and neuroendocrine tumors already estimated the potentiality of this new treatment. To validate the technique, prototypes of the intraoperative probe required by the technique to detect $\\beta^-$ radiation have been developed. This paper discusses the design details of the device and the tests performed in laboratory. In such tests particular care has to be taken to reproduce the surgical field conditions. The innovative technique to produce specific phantoms and the dedicated testing protocols is described in detail.

  14. Intraoperative β{sup -} detecting probe for radio-guided surgery in tumour resection

    SciTech Connect

    Solfaroli Camillocci, Elena; Bellini, Fabio; Bocciy, Valerio; Collamatiyz, Francesco; Faccini, Riccardo; Paramattiy, Riccardo; Paterayz, Vincenzo; Pinciy, Davide; Recchiay, Luigi; Sciubbayz, Adalberto; Senzacqua, Martina; Voenay, Cecilia; Morgantiy, Silvio; De Luciax, Erika; Matteixk, Ilaria; Sartizx, Alessio; Russomando, Aandrea; Marafiniy, Michela

    2015-07-01

    The development of the β{sup -} based radio-guided surgery aims to extend the technique to those tumours where surgery is the only possible treatment and the assessment of the resection would most profit from the low background around the lesion, as for brain tumours. Feasibility studies on meningioma and gliomas already estimated the potentiality of this new treatment. To validate the technique, a prototype of the intraoperative probe detecting β{sup -} decays and specific phantoms simulating tumour remnant patterns embedded in healthy tissue have been realized. The response of the probe in this simulated environment is tested with dedicated procedures. This document discusses the innovative aspects of the method, the status of the developed intraoperative β{sup -} detecting probe and the results of the preclinical tests. (authors)

  15. Multimodality Image Fusion-Guided Procedures: Technique, Accuracy, and Applications

    SciTech Connect

    Abi-Jaoudeh, Nadine; Kruecker, Jochen; Kadoury, Samuel; Kobeiter, Hicham; Venkatesan, Aradhana M. Levy, Elliot Wood, Bradford J.

    2012-10-15

    Personalized therapies play an increasingly critical role in cancer care: Image guidance with multimodality image fusion facilitates the targeting of specific tissue for tissue characterization and plays a role in drug discovery and optimization of tailored therapies. Positron-emission tomography (PET), magnetic resonance imaging (MRI), and contrast-enhanced computed tomography (CT) may offer additional information not otherwise available to the operator during minimally invasive image-guided procedures, such as biopsy and ablation. With use of multimodality image fusion for image-guided interventions, navigation with advanced modalities does not require the physical presence of the PET, MRI, or CT imaging system. Several commercially available methods of image-fusion and device navigation are reviewed along with an explanation of common tracking hardware and software. An overview of current clinical applications for multimodality navigation is provided.

  16. Extending the ICRF to Higher Radio Frequencies: Imaging and Source Structure

    NASA Technical Reports Server (NTRS)

    Boboltz, David A.; Fey, Alan L.; Charlot, Patrick; Fomalont, Edward B.; Lanyi, Gabor E.; Zhang, Li-Wei

    2004-01-01

    We present imaging results and source structure analysis of extragalactic radio sources observed using the Very Long Baseline Array (VLBA) at 24 GHz and 43 GHz as part of an ongoing NASA, USNO, NRAO and Bordeaux Observatory collaboration to extend the International Celestial Reference Frame (ICRF) to higher radio frequencies. The K/Q-band image database now includes images of 108 sources at 43 GHz (Q-braid) and images of 230 sources at 24 GHz (K-band). Preliminary analysis of the observations taken to date shows that the sources are generally more compact as one goes from the ICRF frequency of 8.4 GHz to 24 GHz. This result is consistent with the standard theory of compact extragalactic radio sources and suggests that reference frames defined at these higher radio frequencies will be less susceptible to the effects of intrinsic source structure than those defined at lower frequencies.

  17. [Comparison of various image guided radiation therapy systems; image-guided localization accuracy and patient throughput].

    PubMed

    Takenaga, Eriko; Nakaguchi, Yuji; Maruyama, Masato; Nagasue, Nozomu; Kakei, Kiyotaka; Kai, Yudai; Kouno, Tomohiro; Sasaki, Motoharu; Hashida, Masahiro

    2012-01-01

    In this study, we evaluated various image guided radiation therapy (IGRT) systems regarding accuracy and patient throughput for conventional radiation therapy. We compared between 2D-2D match (the collation by 2 X-rays directions), cone beam computed tomography (CBCT), and ExacTrac X-Ray system using phantom for CLINAC iX and Synergy. All systems were able to correct within almost 1 mm. ExacTrac X-Ray system showed in particular a high accuracy. As for patient throughput, ExacTrac X-Ray system was the fastest system and 2D-2D match for Synergy was the slowest. All systems have enough ability with regard to accuracy and patient throughput on clinical use. ExacTrac X-Ray system showed superiority with accuracy and throughput, but it is important to note that we have to choose the IGRT technique depending on the treatment site, the purpose, and the patient's state.

  18. Robotic Image-Guided Needle Interventions of the Prostate

    PubMed Central

    Mozer, Pierre C; Partin, Alan W; Stoianovici, Dan

    2009-01-01

    Prostate biopsy and needle-directed prostate therapies are currently performed free-handed or with needle external templates under ultrasound guidance. Direct image-guided intervention robots are modern instruments that have the potential to substantially enhance these procedures. These may increase the accuracy and repeatability with which needles are placed in the gland. The authors’ group has developed a robot for precise prostate targeting that operates remotely alongside the patient in the magnetic resonance imaging scanner, as guided according to the image. PMID:19390670

  19. Digital document imaging systems: An overview and guide

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This is an aid to NASA managers in planning the selection of a Digital Document Imaging System (DDIS) as a possible solution for document information processing and storage. Intended to serve as a manager's guide, this document contains basic information on digital imaging systems, technology, equipment standards, issues of interoperability and interconnectivity, and issues related to selecting appropriate imaging equipment based upon well defined needs.

  20. Body-mounted robotic instrument guide for image-guided cryotherapy of renal cancer

    PubMed Central

    Hata, Nobuhiko; Song, Sang-Eun; Olubiyi, Olutayo; Arimitsu, Yasumichi; Fujimoto, Kosuke; Kato, Takahisa; Tuncali, Kemal; Tani, Soichiro; Tokuda, Junichi

    2016-01-01

    Purpose: Image-guided cryotherapy of renal cancer is an emerging alternative to surgical nephrectomy, particularly for those who cannot sustain the physical burden of surgery. It is well known that the outcome of this therapy depends on the accurate placement of the cryotherapy probe. Therefore, a robotic instrument guide may help physicians aim the cryotherapy probe precisely to maximize the efficacy of the treatment and avoid damage to critical surrounding structures. The objective of this paper was to propose a robotic instrument guide for orienting cryotherapy probes in image-guided cryotherapy of renal cancers. The authors propose a body-mounted robotic guide that is expected to be less susceptible to guidance errors caused by the patient’s whole body motion. Methods: Keeping the device’s minimal footprint in mind, the authors developed and validated a body-mounted, robotic instrument guide that can maintain the geometrical relationship between the device and the patient’s body, even in the presence of the patient’s frequent body motions. The guide can orient the cryotherapy probe with the skin incision point as the remote-center-of-motion. The authors’ validation studies included an evaluation of the mechanical accuracy and position repeatability of the robotic instrument guide. The authors also performed a mock MRI-guided cryotherapy procedure with a phantom to compare the advantage of robotically assisted probe replacements over a free-hand approach, by introducing organ motions to investigate their effects on the accurate placement of the cryotherapy probe. Measurements collected for performance analysis included accuracy and time taken for probe placements. Multivariate analysis was performed to assess if either or both organ motion and the robotic guide impacted these measurements. Results: The mechanical accuracy and position repeatability of the probe placement using the robotic instrument guide were 0.3 and 0.1 mm, respectively, at a depth

  1. Image-guided plasma therapy of cutaneous wound

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiwu; Ren, Wenqi; Yu, Zelin; Zhang, Shiwu; Yue, Ting; Xu, Ronald

    2014-02-01

    The wound healing process involves the reparative phases of inflammation, proliferation, and remodeling. Interrupting any of these phases may result in chronically unhealed wounds, amputation, or even patient death. Despite the clinical significance in chronic wound management, no effective methods have been developed for quantitative image-guided treatment. We integrated a multimodal imaging system with a cold atmospheric plasma probe for image-guided treatment of chronic wound. Multimodal imaging system offers a non-invasive, painless, simultaneous and quantitative assessment of cutaneous wound healing. Cold atmospheric plasma accelerates the wound healing process through many mechanisms including decontamination, coagulation and stimulation of the wound healing. The therapeutic effect of cold atmospheric plasma is studied in vivo under the guidance of a multimodal imaging system. Cutaneous wounds are created on the dorsal skin of the nude mice. During the healing process, the sample wound is treated by cold atmospheric plasma at different controlled dosage, while the control wound is healed naturally. The multimodal imaging system integrating a multispectral imaging module and a laser speckle imaging module is used to collect the information of cutaneous tissue oxygenation (i.e. oxygen saturation, StO2) and blood perfusion simultaneously to assess and guide the plasma therapy. Our preliminary tests show that cold atmospheric plasma in combination with multimodal imaging guidance has the potential to facilitate the healing of chronic wounds.

  2. Groupwise Image Registration Guided by a Dynamic Digraph of Images.

    PubMed

    Tang, Zhenyu; Fan, Yong

    2016-04-01

    For groupwise image registration, graph theoretic methods have been adopted for discovering the manifold of images to be registered so that accurate registration of images to a group center image can be achieved by aligning similar images that are linked by the shortest graph paths. However, the image similarity measures adopted to build a graph of images in the extant methods are essentially pairwise measures, not effective for capturing the groupwise similarity among multiple images. To overcome this problem, we present a groupwise image similarity measure that is built on sparse coding for characterizing image similarity among all input images and build a directed graph (digraph) of images so that similar images are connected by the shortest paths of the digraph. Following the shortest paths determined according to the digraph, images are registered to a group center image in an iterative manner by decomposing a large anatomical deformation field required to register an image to the group center image into a series of small ones between similar images. During the iterative image registration, the digraph of images evolves dynamically at each iteration step to pursue an accurate estimation of the image manifold. Moreover, an adaptive dictionary strategy is adopted in the groupwise image similarity measure to ensure fast convergence of the iterative registration procedure. The proposed method has been validated based on both simulated and real brain images, and experiment results have demonstrated that our method was more effective for learning the manifold of input images and achieved higher registration accuracy than state-of-the-art groupwise image registration methods.

  3. Thermal Imaging of Medical Saw Blades and Guides

    SciTech Connect

    Dinwiddie, Ralph Barton; Steffner, Thomas E

    2007-01-01

    Better Than New, LLC., has developed a surface treatment to reduce the friction and wear of orthopedic saw blades and guides. The medical saw blades were thermally imaged while sawing through fresh animal bone and an IR camera was used to measure the blade temperature as it exited the bone. The thermal performance of as-manufactured saw blades was compared to surface-treated blades, and a freshly used blade was used for temperature calibration purposes in order to account for any emissivity changes due to organic transfer layers. Thermal imaging indicates that the treated saw blades cut faster and cooler than untreated blades. In orthopedic surgery, saw guides are used to perfectly size the bone to accept a prosthesis. However, binding can occur between the blade and guide because of misalignment. This condition increases the saw blade temperature and may result in tissue damage. Both treated ad untreated saw guides were also studied. The treated saw guide operated at a significantly lower temperature than untreated guide. Saw blades and guides that operate at a cooler temperature are expected to reduce the amount of tissue damage (thermal necrosis) and may reduce the number of post-operative complications.

  4. Diffuse reflectance imaging: a tool for guided biopsy

    NASA Astrophysics Data System (ADS)

    Jayanthi, Jayaraj L.; Subhash, Narayanan; Manju, Stephen; Nisha, Unni G.; Beena, Valappil T.

    2012-01-01

    Accurate diagnosis of premalignant or malignant oral lesions depends on the quality of the biopsy, adequate clinical information and correct interpretation of the biopsy results. The major clinical challenge is to precisely locate the biopsy site in a clinically suspicious lesion. Dips due to oxygenated hemoglobin absorption have been noticed at 545 and 575 nm in the diffusely reflected white light spectra of oral mucosa and the intensity ratio R545/R575 has been found suited for early detection of oral pre-cancers. A multi-spectral diffuse reflectance (DR) imaging system has been developed consisting of an electron multiplying charge coupled device (EMCCD) camera and a liquid crystal tunable filter for guiding the clinician to an optimal biopsy site. Towards this DR images were recorded from 27 patients with potentially malignant lesions on their tongue (dorsal, lateral and ventral sides) and from 44 healthy controls at 545 and 575 nm with the DR imaging system. False colored ratio image R545/R575 of the lesion provides a visual discerning capability that helps in locating the most malignant site for biopsy. Histopathological report of guided biopsy showed that out of the 27 patients 16 were cancers, 9 pre-cancers and 2 lichen planus. In this clinical trial DR imaging has correctly guided 25 biopsy sites, yielding a sensitivity of 93% and a specificity of 98%, thereby establishing the potential of DR imaging as a tool for guided biopsy.

  5. Multifunctional ultrasound contrast agents for imaging guided photothermal therapy.

    PubMed

    Guo, Caixin; Jin, Yushen; Dai, Zhifei

    2014-05-21

    Among all the imaging techniques, ultrasound imaging has a unique advantage due to its features of real-time, low cost, high safety, and portability. Ultrasound contrast agents (UCAs) have been widely used to enhance ultrasonic signals. One of the most exciting features of UCAs for use in biomedicine is the possibility of easily putting new combinations of functional molecules into microbubbles (MBs), which are the most routinely used UCAs. Various therapeutic agents and medical nanoparticles (quantum dots, gold, Fe3O4, etc.) can be loaded into ultrasound-responsive MBs. Hence, UCAs can be developed as multifunctional agents that integrate capabilities for early detection and diagnosis and for imaging guided therapy of various diseases. The current review will focus on such state-of-the-art UCA platforms that have been exploited for multimodal imaging and for imaging guided photothermal therapy.

  6. Intraoperative probe detecting β- decays in brain tumour radio-guided surgery

    NASA Astrophysics Data System (ADS)

    Solfaroli Camillocci, E.; Bocci, V.; Chiodi, G.; Collamati, F.; Donnarumma, R.; Faccini, R.; Mancini Terracciano, C.; Marafini, M.; Mattei, I.; Muraro, S.; Recchia, L.; Rucinski, A.; Russomando, A.; Toppi, M.; Traini, G.; Morganti, S.

    2017-02-01

    Radio-guided surgery (RGS) is a technique to intraoperatively detect tumour remnants, favouring a radical resection. Exploiting β- emitting tracers provides a higher signal to background ratio compared to the established technique with γ radiation, allowing the extension of the RGS applicability range. We developed and tested a detector based on para-terphenyl scintillator with high sensitivity to low energy electrons and almost transparent to γs to be used as intraoperative probe for RGS with β- emitting tracer. Portable read out electronics was customised to match the surgeon needs. This probe was used for preclinical test on specific phantoms and a test on ;ex vivo; specimens from patients affected by meningioma showing very promising results for the application of this new technique on brain tumours. In this paper, the prototype of the intraoperative probe and the tests are discussed; then, the results on meningioma are used to make predictions on the performance of the probe detecting residuals of a more challenging and more interesting brain tumour: the glioma.

  7. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method

    PubMed Central

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-01-01

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This “open-shielded” device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities. PMID:27841358

  8. A low cost training phantom model for radio-guided localization techniques in occult breast lesions.

    PubMed

    Aydogan, Fatih; Mallory, Melissa Anne; Tukenmez, Mustafa; Sagara, Yasuaki; Ozturk, Erkan; Ince, Yavuz; Celik, Varol; Akca, Tamer; Golshan, Mehra

    2015-09-01

    Radio-guided localization (RGL) for identifying occult breast lesions has been widely accepted as an alternative technique to other localization methods, including those using wire guidance. An appropriate phantom model would be an invaluable tool for practitioners interested in learning the technique of RGL prior to clinical application. The aim of this study was to devise an inexpensive and reproducible training phantom model for RGL. We developed a simple RGL phantom model imitating an occult breast lesion from inexpensive supplies including a pimento olive, a green pea and a turkey breast. The phantom was constructed for a total cost of less than $20 and prepared in approximately 10 min. After the first model's construction, we constructed approximately 25 additional models and demonstrated that the model design was easily reproducible. The RGL phantom is a time- and cost-effective model that accurately simulates the RGL technique for non-palpable breast lesions. Future studies are warranted to further validate this model as an effective teaching tool.

  9. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method.

    PubMed

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-11-14

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This "open-shielded" device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities.

  10. Peering through Jupiter’s clouds with radio spectral imaging

    NASA Astrophysics Data System (ADS)

    de Pater, Imke; Sault, R. J.; Butler, Bryan; DeBoer, David; Wong, Michael H.

    2016-06-01

    Radio wavelengths can probe altitudes in Jupiter’s atmosphere below its visible cloud layers. We used the Very Large Array to map this unexplored region down to ~8 bar, ~100 kilometers below the visible clouds. Our maps reveal a dynamically active planet at pressures less than 2 to 3 bar. A radio-hot belt exists, consisting of relatively transparent regions (a low ammonia concentration, NH3 being the dominant source of opacity) probing depths to over ~8 bar; these regions probably coincide with 5-micrometer hot spots. Just to the south we distinguish an equatorial wave, bringing up ammonia gas from Jupiter’s deep atmosphere. This wave has been theorized to produce the 5-micrometer hot spots; we observed the predicted radio counterpart of such hot spots.

  11. Peering through Jupiter's clouds with radio spectral imaging.

    PubMed

    de Pater, Imke; Sault, R J; Butler, Bryan; DeBoer, David; Wong, Michael H

    2016-06-03

    Radio wavelengths can probe altitudes in Jupiter's atmosphere below its visible cloud layers. We used the Very Large Array to map this unexplored region down to ~8 bar, ~100 kilometers below the visible clouds. Our maps reveal a dynamically active planet at pressures less than 2 to 3 bar. A radio-hot belt exists, consisting of relatively transparent regions (a low ammonia concentration, NH3 being the dominant source of opacity) probing depths to over ~8 bar; these regions probably coincide with 5-micrometer hot spots. Just to the south we distinguish an equatorial wave, bringing up ammonia gas from Jupiter's deep atmosphere. This wave has been theorized to produce the 5-micrometer hot spots; we observed the predicted radio counterpart of such hot spots.

  12. Improved Guided Image Fusion for Magnetic Resonance and Computed Tomography Imaging

    PubMed Central

    Jameel, Amina

    2014-01-01

    Improved guided image fusion for magnetic resonance and computed tomography imaging is proposed. Existing guided filtering scheme uses Gaussian filter and two-level weight maps due to which the scheme has limited performance for images having noise. Different modifications in filter (based on linear minimum mean square error estimator) and weight maps (with different levels) are proposed to overcome these limitations. Simulation results based on visual and quantitative analysis show the significance of proposed scheme. PMID:24695586

  13. The algorithm of construction of a multiring model for the radio image of non-coherent radio sources based on the measured visibility function.

    NASA Astrophysics Data System (ADS)

    Koshovij, V. V.; Lozins'kij, A. B.; Romanishin, I. M.; Romanchev, Yu. V.

    1998-04-01

    The authors consider the problem of constructing a centrosymmetrical model of the radio image of a noncoherent radio source based on the van Cittert-Zernike theorem. They show that it is enough to know the visibility function modulus determined on the (u,v) plane. A new multiring model for the radio image restoration of radio sources based on visibility function measured by radiointerferometric method is proposed. The authors give the algorithm for determination of the number of rings, their angular radii, and flux densities based on Fourier-Bessel series. The radio image of Cas A was restored from measurements performed with the short-base (up to 2000 D/λ) interferometer URAN-3. The model of the large-scale structure deduced from measurements in the metre range, is consistent with results obtained in decametre wavelengths.

  14. Cranial and spinal magnetic resonance imaging: A guide and atlas

    SciTech Connect

    Daniels, D.L.; Haughton, V.M.

    1987-01-01

    This atlas provides a clinical guide to interpreting cranial and spinal magnetic resonance images. The book includes coverage of the cerebrum, temporal bone, and cervical, thoracic, and lumbar spine, with more than 400 scan images depicting both normal anatomy and pathologic findings. Introductory chapters review the practical physics of magnetic resonance (MR) imaging, offer guidelines for interpreting cranial MR scans, and provide coverage of each anatomic region of the cranium and spine. For each region, scans accompanied by captions, show normal anatomic sections matched with MR images. These are followed by MR scans depicting various disease states.

  15. JUICE/RPWI/JENRAGE: a low frequency radio imager at Jupiter

    NASA Astrophysics Data System (ADS)

    Cecconi, B.; Kasaba, Y.; Bergman, J. E. S.; Zarka, P.; Lamy, L.; Hess, S. L. G.; Rothkaehl, H.

    2015-10-01

    The JENRAGE (Jovian Environment Radio Astronomy and Ganymede Exploration) experiment of the Radio and Plasma Waves Instrument (RPWI) on-board JUICE (Jupiter Icy Moon Explorer) is a sensitive, and versatile radio instrument. It will observe radio waves ranging from 80 kHz to 45 MHz at a 100 Msample per second aquisition rate. The instrument is composed of set of 3 electrical dipoles (developed by the Polish team), connected to low noise preamplifiers and conditioning analog filters (built by the Japanese team), then sampled and digitally filtererd into ~300 kHz bands (digital part developed by the Swedish team). This international project is coordinated by B. Cecconi and Y. Kasaba, both co-PI of JUICE/RPWI. Although the radio antenna connected to this instrument have no intrinsic directivity, the JENRAGE measurements can provide instantaneous direction of arrival, flux density and polarization degree of the observed radio waves. Hence, the JENRAGE can be described as an full-sky radio imager. As the instrument provides direction of arrival, radio sources can be located with some assumption on the propagation between the source and the observer. Hence, it is possible to produce radio source maps and correlate them with observations at other wavelengths, such as UV or IR observations of the auroral regions of Jupiter. The flux and polarization measurements together with the time- frequency shape of the radio emissions can also be used to identify the radio emission processes. These features have shown their capabilities on Cassini, with the RPWS/HFR instrument. We will present the JUICE/RPWI/JENRAGE design and the science objectives. Additional science topics linked to the icy satellites, which are currently being assessed, will also be presented.

  16. Imaging the host galaxies of high-redshift radio-quiet QSOs

    NASA Technical Reports Server (NTRS)

    Lowenthal, James D.; Heckman, Timothy M.; Lehnert, Matthew, D.; Elias, J. H.

    1995-01-01

    We present new deep K-band and optical images of four radio-quiet QSOs at z approximately = 1 and six radio-quiet QSOs at z approximately = 2.5, as well as optical images only of six more at z approximately = 2.5. We have examined the images carefully for evidence of extended 'fuzz' from any putative QSO host galaxy. None of the z approximately = 2.5 QSOs shows any extended emission, and only two of the z approximately = 1 QSOs show marginal evidence for extended emission. Our 3 sigma detection limits in the K images, m(sub K) approximately = 21 for an isolated source, would correspond approximately to an unevolved L(sup star) elliptical galaxy at z = 2.5 or 2-3 mag fainter than an L(sup star) elliptical at z = 1, although our limits on host galaxy light are weaker than this due to the difficulty of separating galaxy light from QSO light. We simulate simple models of disk and elliptical host galaxies, and find that the marginal emission around the two z approximately = 1 QSOs can be explained by disks or bulges that are approximately 1-2 mag brighter than an unevolved L(sup star) galaxy in one case and approximately 1.5-2.5 mag brighter than L(sub star) in the other. For two other z approximately = 1 QSOs, we have only upper limits (L approximately = L(sup star)). The hosts of the high-redshift sample must be no brighter than about 3 mag above an unevolved L(sup star) galaxy, and are at least 1 magnitude fainter than the hosts of radio-loud QSOs at the same redshift. If the easily detected K-band light surrounding a previous sample of otherwise similar but radio-loud QSOs is starlight, then it must evolve on timescales of greater than or approximately equal to 10(exp 8) yr (e.g., Chambers & Charlot 1990); therefore our non-detection of host galaxy fuzz around radio-quiet QSOs supports the view that high-redshift radio-quiet and radio-loud QSOs inhabit different host objects, rather than being single types of objects that turn their radio emission on and off over

  17. Image-Guided Radiotherapy and -Brachytherapy for Cervical Cancer

    PubMed Central

    Dutta, Suresh; Nguyen, Nam Phong; Vock, Jacqueline; Kerr, Christine; Godinez, Juan; Bose, Satya; Jang, Siyoung; Chi, Alexander; Almeida, Fabio; Woods, William; Desai, Anand; David, Rick; Karlsson, Ulf Lennart; Altdorfer, Gabor

    2015-01-01

    Conventional radiotherapy for cervical cancer relies on clinical examination, 3-dimensional conformal radiotherapy (3D-CRT), and 2-dimensional intracavitary brachytherapy. Excellent local control and survival have been obtained for small early stage cervical cancer with definitive radiotherapy. For bulky and locally advanced disease, the addition of chemotherapy has improved the prognosis but toxicity remains significant. New imaging technology such as positron-emission tomography and magnetic resonance imaging has improved tumor delineation for radiotherapy planning. Image-guided radiotherapy (IGRT) may decrease treatment toxicity of whole pelvic radiation because of its potential for bone marrow, bowel, and bladder sparring. Tumor shrinkage during whole pelvic IGRT may optimize image-guided brachytherapy (IGBT), allowing for better local control and reduced toxicity for patients with cervical cancer. IGRT and IGBT should be integrated in future prospective studies for cervical cancer. PMID:25853092

  18. Image-guided radiotherapy and -brachytherapy for cervical cancer.

    PubMed

    Dutta, Suresh; Nguyen, Nam Phong; Vock, Jacqueline; Kerr, Christine; Godinez, Juan; Bose, Satya; Jang, Siyoung; Chi, Alexander; Almeida, Fabio; Woods, William; Desai, Anand; David, Rick; Karlsson, Ulf Lennart; Altdorfer, Gabor

    2015-01-01

    Conventional radiotherapy for cervical cancer relies on clinical examination, 3-dimensional conformal radiotherapy (3D-CRT), and 2-dimensional intracavitary brachytherapy. Excellent local control and survival have been obtained for small early stage cervical cancer with definitive radiotherapy. For bulky and locally advanced disease, the addition of chemotherapy has improved the prognosis but toxicity remains significant. New imaging technology such as positron-emission tomography and magnetic resonance imaging has improved tumor delineation for radiotherapy planning. Image-guided radiotherapy (IGRT) may decrease treatment toxicity of whole pelvic radiation because of its potential for bone marrow, bowel, and bladder sparring. Tumor shrinkage during whole pelvic IGRT may optimize image-guided brachytherapy (IGBT), allowing for better local control and reduced toxicity for patients with cervical cancer. IGRT and IGBT should be integrated in future prospective studies for cervical cancer.

  19. Stripe noise removal for infrared images using guided filter

    NASA Astrophysics Data System (ADS)

    Zhang, Shengwei; Xiang, Wei; Xu, Baoshu; Feng, Bin

    2016-10-01

    Pixels of different columns in the infrared Focal Plane Array (FPA) have different readout circuit channels, amplifiers in different channels, different 1/f noise characteristics. Such noise may cause obvious stripe noise in the infrared images and degrades the quality of captured images. First, analyzed a stripe noise removal method making use of blurred infrared image based on average filter and pointed out the limitation in this method. Then, gave the reason that lead to the limitation. On the basis of this, introduced guided filter, and came up with an acquiring strip noise correction term method using 1D guided filter to handle the average row vector of the blurred image. The simulation experiment shows that this method is effective and efficient in removing stripe noise. Moreover, this method has a low time complexity, and can be easily implemented in the project.

  20. Estimating Single and Multiple Target Locations Using K-Means Clustering with Radio Tomographic Imaging in Wireless Sensor Networks

    DTIC Science & Technology

    2015-03-26

    ESTIMATING SINGLE AND MULTIPLE TARGET LOCATIONS USING K-MEANS CLUSTERING WITH RADIO TOMOGRAPHIC IMAGING IN WIRELESS SENSOR NETWORKS THESIS Jeffrey K...AND MULTIPLE TARGET LOCATIONS USING K-MEANS CLUSTERING WITH RADIO TOMOGRAPHIC IMAGING IN WIRELESS SENSOR NETWORKS THESIS Presented to the Faculty...SINGLE AND MULTIPLE TARGET LOCATIONS USING K-MEANS CLUSTERING WITH RADIO TOMOGRAPHIC IMAGING IN WIRELESS SENSOR NETWORKS Jeffrey K. Nishida, B.S.E.E

  1. Image Guided Biodistribution and Pharmacokinetic Studies of Theranostics

    PubMed Central

    Ding, Hong; Wu, Fang

    2012-01-01

    Image guided technique is playing an increasingly important role in the investigation of the biodistribution and pharmacokinetics of drugs or drug delivery systems in various diseases, especially cancers. Besides anatomical imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), molecular imaging strategy including optical imaging, positron emission tomography (PET) and single-photon emission computed tomography (SPECT) will facilitate the localization and quantization of radioisotope or optical probe labeled nanoparticle delivery systems in the category of theranostics. The quantitative measurement of the bio-distribution and pharmacokinetics of theranostics in the fields of new drug/probe development, diagnosis and treatment process monitoring as well as tracking the brain-blood-barrier (BBB) breaking through by high sensitive imaging method, and the applications of the representative imaging modalities are summarized in this review. PMID:23227121

  2. From clinical imaging and computational models to personalised medicine and image guided interventions.

    PubMed

    Hawkes, David J

    2016-10-01

    This short paper describes the development of the UCL Centre for Medical Image Computing (CMIC) from 2006 to 2016, together with reference to historical developments of the Computational Imaging sciences Group (CISG) at Guy's Hospital. Key early work in automated image registration led to developments in image guided surgery and improved cancer diagnosis and therapy. The work is illustrated with examples from neurosurgery, laparoscopic liver and gastric surgery, diagnosis and treatment of prostate cancer and breast cancer, and image guided radiotherapy for lung cancer.

  3. Application of open source image guided therapy software in MR-guided therapies.

    PubMed

    Hata, Nobuhiko; Piper, Steve; Jolesz, Ferenc A; Tempany, Clare M C; Black, Peter McL; Morikawa, Shigehiro; Iseki, Horoshi; Hashizume, Makoto; Kikinis, Ron

    2007-01-01

    We present software engineering methods to provide free open-source software for MR-guided therapy. We report that graphical representation of the surgical tools, interconnectively with the tracking device, patient-to-image registration, and MRI-based thermal mapping are crucial components of MR-guided therapy in sharing such software. Software process includes a network-based distribution mechanism by multi-platform compiling tool CMake, CVS, quality assurance software DART. We developed six procedures in four separate clinical sites using proposed software engineering and process, and found the proposed method is feasible to facilitate multicenter clinical trial of MR-guided therapies. Our future studies include use of the software in non-MR-guided therapies.

  4. Radio imaging of a type IVM radio burst on the 14th of August 2010

    SciTech Connect

    Bain, H. M.; Krucker, S.; Saint-Hilaire, P.; Raftery, C. L.

    2014-02-10

    Propagating coronal mass ejections (CMEs) are often accompanied by burst signatures in radio spectrogram data. We present Nançay Radioheliograph observations of a moving source of broadband radio emission, commonly referred to as a type IV radio burst (type IVM), which occurred in association with a CME on the 14th of August 2010. The event was well observed at extreme ultraviolet (EUV) wavelengths by SDO/AIA and PROBA2/SWAP, and by the STEREO SECCHI and SOHO LASCO white light (WL) coronagraphs. The EUV and WL observations show the type IVM source to be cospatial with the CME core. The observed spectra is well fitted by a power law with a negative slope, which is consistent with optically thin gyrosynchrotron emission. The spectrum shows no turn over at the lowest Nançay frequencies. By comparing simulated gyrosynchrotron spectra with Nançay Radioheliograph observations, and performing a rigorous parameter search we are able to constrain several key parameters of the underlying plasma. Simulated spectra found to fit the data suggest a nonthermal electron distribution with a low energy cutoff of several tens to 100 keV, with a nonthermal electron density in the range 10{sup 0}-10{sup 2} cm{sup –3}, in a magnetic field of a few Gauss. The nonthermal energy content of the source is found to contain 0.001%-0.1% of the sources thermal energy content. Furthermore, the energy loss timescale for this distribution equates to several hours, suggesting that the electrons could be accelerated during the CME initiation or early propagation phase and become trapped in the magnetic structure of the CME core without the need to be replenished.

  5. Optoacoustic Imaging for Guiding and Monitoring HIFU Therapy

    NASA Astrophysics Data System (ADS)

    Chitnis, Parag V.; Brecht, Hans P.; Su, Richard; Oraevsky, Alexander A.

    2011-09-01

    Although high-intensity focused ultrasound (HIFU) has exciting potential for noninvasively treating tumors and cardiac diseases, its clinical acceptance is hindered by the lack of a reliable and cost-effective method of noninvasively guiding and monitoring the treatment. The present study investigated the feasibility of employing optoacoustic imaging (OAI) for guiding and monitoring HIFU therapy. OAI combines molecular specificity provided by optical imaging and the resolution provided by diagnostic ultrasound. A 3-D optoacoustic imaging system was used to visualize thermal lesions produced in excised tissue specimens and in vivo mice using high intensity focused ultrasound (HIFU). A 7.5 MHz surgical, focused transducer with a radius of curvature of 35 mm and an aperture of 23 mm generated HIFU. A pulsed laser, which could operate at 755 nm and 1064 nm, illuminated the specimens. Tomographic images were obtained using a 64 element curved array while the specimens were rotated incrementally. Images were acquired before and after HIFU exposure. The images were then combined to reconstruct 3-D volume images (voxel resolution 0.5 mm). Optoacoustic images using 1064-nm illumination provided visualization of HIFU lesions. The location and the extent of the lesions were confirmed upon dissection. These preliminary results demonstrate the potential of optoacoustic imaging to assess and monitor HIFU therapy.

  6. [Application and overview of image guided surgery system].

    PubMed

    Su, Wenkui; Zhang, Yuli; Li, Dongmei; Zhou, Zhaoying

    2010-07-01

    This paper introduces the development and the key technology of image guided Surgery Systems (IGSS) and analyses its prospect in this paper. IGSS can be used in clinical surgery as an assistant tool, and it would be an advanced medical equipment combined with medical robotics.

  7. Image Display And Manipulation System (IDAMS), user's guide

    NASA Technical Reports Server (NTRS)

    Cecil, R. W.

    1972-01-01

    A combination operator's guide and user's handbook for the Image Display and Manipulation System (IDAMS) is reported. Information is presented to define how to operate the computer equipment, how to structure a run deck, and how to select parameters necessary for executing a sequence of IDAMS task routines. If more detailed information is needed on any IDAMS program, see the IDAMS program documentation.

  8. Improved Image-Guided Laparoscopic Prostatectomy

    DTIC Science & Technology

    2011-08-01

    pancreas, lymph nodes, and thyroid .[1,2,3,4,5] Ultrasound elastography is thus a very promising image guidance method for robot-assisted procedures...Li, Z., Zhang, X., Chen, M., and Luo, Z., “Real-time ultrasound elastography in the differential diagnosis of benign and malignant thyroid nodules...AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Laparoscopic Ultrasound

  9. MORESANE: MOdel REconstruction by Synthesis-ANalysis Estimators. A sparse deconvolution algorithm for radio interferometric imaging

    NASA Astrophysics Data System (ADS)

    Dabbech, A.; Ferrari, C.; Mary, D.; Slezak, E.; Smirnov, O.; Kenyon, J. S.

    2015-04-01

    Context. Recent years have been seeing huge developments of radio telescopes and a tremendous increase in their capabilities (sensitivity, angular and spectral resolution, field of view, etc.). Such systems make designing more sophisticated techniques mandatory not only for transporting, storing, and processing this new generation of radio interferometric data, but also for restoring the astrophysical information contained in such data. Aims.In this paper we present a new radio deconvolution algorithm named MORESANEand its application to fully realistic simulated data of MeerKAT, one of the SKA precursors. This method has been designed for the difficult case of restoring diffuse astronomical sources that are faint in brightness, complex in morphology, and possibly buried in the dirty beam's side lobes of bright radio sources in the field. Methods.MORESANE is a greedy algorithm that combines complementary types of sparse recovery methods in order to reconstruct the most appropriate sky model from observed radio visibilities. A synthesis approach is used for reconstructing images, in which the synthesis atoms representing the unknown sources are learned using analysis priors. We applied this new deconvolution method to fully realistic simulations of the radio observations of a galaxy cluster and of an HII region in M 31. Results.We show that MORESANE is able to efficiently reconstruct images composed of a wide variety of sources (compact point-like objects, extended tailed radio galaxies, low-surface brightness emission) from radio interferometric data. Comparisons with the state of the art algorithms indicate that MORESANE provides competitive results in terms of both the total flux/surface brightness conservation and fidelity of the reconstructed model. MORESANE seems particularly well suited to recovering diffuse and extended sources, as well as bright and compact radio sources known to be hosted in galaxy clusters.

  10. Technique development for photoacoustic imaging guided interventions

    NASA Astrophysics Data System (ADS)

    Cheng, Qian; Zhang, Haonan; Yuan, Jie; Feng, Ting; Xu, Guan; Wang, Xueding

    2015-03-01

    Laser-induced thermotherapy (LITT), i.e. tissue destruction induced by a local increase of temperature by means of laser light energy transmission, has been frequently used for minimally invasive treatments of various diseases such as benign thyroid nodules and liver cancer. The emerging photoacoustic (PA) imaging, when integrated with ultrasound (US), could contribute to LITT procedure. PA can enable a good visualization of percutaneous apparatus deep inside tissue and, therefore, can offer accurate guidance of the optical fibers to the target tissue. Our initial experiment demonstrated that, by picking the strong photoacoustic signals generated at the tips of optical fibers as a needle, the trajectory and position of the fibers could be visualized clearly using a commercial available US unit. When working the conventional US Bscan mode, the fibers disappeared when the angle between the fibers and the probe surface was larger than 60 degree; while working on the new PA mode, the fibers could be visualized without any problem even when the angle between the fibers and the probe surface was larger than 75 degree. Moreover, with PA imaging function integrated, the optical fibers positioned into the target tissue, besides delivering optical energy for thermotherapy, can also be used to generate PA signals for on-line evaluation of LITT. Powered by our recently developed PA physio-chemical analysis, PA measurements from the tissue can provide a direct and accurate feedback of the tissue responses to laser ablation, including the changes in not only chemical compositions but also histological microstructures. The initial experiment on the rat liver model has demonstrated the excellent sensitivity of PA imaging to the changes in tissue temperature rise and tissue status (from native to coagulated) when the tissue is treated in vivo with LITT.

  11. Fast Radiometry Guided Fusion of Disparity Images

    NASA Astrophysics Data System (ADS)

    Schmid, Stephan; Fritsch, Dieter

    2016-06-01

    Previous work on disparity map fusion has mostly focused on geometric or statistical properties of disparity maps. Since failure of stereo algorithms is often consistent in many frames of a scene, it cannot be detected by such methods. Instead, we propose to use radiometric information from the original camera images together with externally supplied camera pose information to detect mismatches. As radiometric information is local information, the computations in the proposed algorithm for disparity fusion can be decoupled and parallelized to a very large degree, which allows us to easily achieve real-time performance.

  12. Minimally invasive image-guided therapies for hepatocellular carcinoma

    PubMed Central

    Abdelsalam, Mohamed E; Murthy, Ravi; Avritscher, Rony; Mahvash, Armeen; Wallace, Michael J; Kaseb, Ahmed O; Odisio, Bruno C

    2016-01-01

    Hepatocellular carcinoma (HCC) is the fifth most frequently occurring cancer globally and predominantly develops in the setting of various grades of underlying chronic liver disease, which affects management decisions. Image-guided percutaneous ablative or transarterial therapies have acquired wide acceptance in HCC management as a single treatment modality or combined with other treatment options in patients who are not amenable for surgery. Recently, such treatment modalities have also been used for bridging or downsizing before definitive treatment (ie, surgical resection or liver transplantation). This review focuses on the use of minimally invasive image-guided locoregional therapies for HCC. Additionally, it highlights recent advancements in imaging and catheter technology, embolic materials, chemotherapeutic agents, and delivery techniques; all lead to improved patient outcomes, thereby increasing the interest in these invasive techniques. PMID:27785450

  13. Image Fusion During Vascular and Nonvascular Image-Guided Procedures☆

    PubMed Central

    Abi-Jaoudeh, Nadine; Kobeiter, Hicham; Xu, Sheng; Wood, Bradford J.

    2013-01-01

    Image fusion may be useful in any procedure where previous imaging such as positron emission tomography, magnetic resonance imaging, or contrast-enhanced computed tomography (CT) defines information that is referenced to the procedural imaging, to the needle or catheter, or to an ultrasound transducer. Fusion of prior and intraoperative imaging provides real-time feedback on tumor location or margin, metabolic activity, device location, or vessel location. Multimodality image fusion in interventional radiology was initially introduced for biopsies and ablations, especially for lesions only seen on arterial phase CT, magnetic resonance imaging, or positron emission tomography/CT but has more recently been applied to other vascular and nonvascular procedures. Two different types of platforms are commonly used for image fusion and navigation: (1) electromagnetic tracking and (2) cone-beam CT. Both technologies would be reviewed as well as their strengths and weaknesses, indications, when to use one vs the other, tips and guidance to streamline use, and early evidence defining clinical benefits of these rapidly evolving, commercially available and emerging techniques. PMID:23993079

  14. Magnetic Resonance Imaging Guided Vacuum Assisted and Core Needle Biopsies

    PubMed Central

    Kılıç, Fahrettin; Eren, Abdulkadir; Tunç, Necmettin; Velidedeoğlu, Mehmet; Bakan, Selim; Aydoğan, Fatih; Çelik, Varol; Gazioğlu, Ertuğrul; Yılmaz, Mehmet Halit

    2016-01-01

    Objective The purpose of this study to present the results of Magnetic resonance imaging (MRI) guided cutting needle biopsy procedures of suspicious breast lesions that can be solely detected on Magnetic resonance (MR) examination. Materials and Methods The study included 48 patients with 48 lesions which were solely be observed in breast MRI, indistinguishable in ultrasonography and mammography, for MR guided vacuum-assisted cutting needle biopsy and 42 patients with 42 lesions for MR guided cutting needle biopsy for the lesions of the same nature. MR imaging was performed using a 1.5-Tesla MRI device. Acquired MR images were determined and biopsy protocol was performed using computer-aided diagnosis system on the workstation. Vacuum biopsies were performed using 10 G or 12 G automatic biopsy systems, cutting needle biopsy procedures were performed using fully automated 12 G biopsy needle. Results All biopsy procedures were finalized successfully without major complications. The lesions were 54 mass (60%), 28 were non-mass contrast enhancement (31%) and 8 were foci (9%) in the MR examination. Histopathological evaluation revealed 18 malignant (invasive, in-situ ductal carcinoma and lobular carcinoma), 66 benign (apocrine metaplasia, fibrosis, fibroadenomatoid lesion, sclerosing adenosis, fibrocystic disease and mild-to-severe epithelial proliferation) and 6 high-risk (atypical ductal hyperplasia, intraductal papilloma, radial scar) lesions. Conclusion Magnetic resonance guided vacuum and cutting needle biopsy methods are successful methods fort he evaluation of solely MRI detected suspicious breast lesions. There are several advantages relative to each other in both methods.

  15. Image-guided distal radius osteotomy using patient-specific instrument guides.

    PubMed

    Kunz, Manuela; Ma, Burton; Rudan, John F; Ellis, Randy E; Pichora, David R

    2013-08-01

    In this article, we describe a method for computer-assisted distal radius osteotomies in which computer-generated, patient-specific plastic guides are used for intraoperative guidance. Before surgery, the correction and plate location are planned using computed tomography scans for both radii and ulnae, and the planned locations of the distal and proximal drill holes for the plate are saved. A plastic, patient-specific instrument guide is created using a rapid prototyping machine into which a mirror image of intraoperative, accessible bone structure of the distal radius is integrated. This allows for unique positioning of the guide during surgery. For each planned drill location, a guidance hole is incorporated into the guide. During surgery, a conventional incision is made, and the guide is positioned on the radius. The surgeon drills the holes for the plate screws into the intact radius and performs the osteotomy using the conventional technique. Using the predrilled holes, the surgeon affixes the plate to the radius fragments. The guides are easy to integrate into the surgical workflow and minimize the need for intraoperative fluoroscopy for guidance of the procedure.

  16. Streak image denoising and segmentation using adaptive Gaussian guided filter.

    PubMed

    Jiang, Zhuocheng; Guo, Baoping

    2014-09-10

    In streak tube imaging lidar (STIL), streak images are obtained using a CCD camera. However, noise in the captured streak images can greatly affect the quality of reconstructed 3D contrast and range images. The greatest challenge for streak image denoising is reducing the noise while preserving details. In this paper, we propose an adaptive Gaussian guided filter (AGGF) for noise removal and detail enhancement of streak images. The proposed algorithm is based on a guided filter (GF) and part of an adaptive bilateral filter (ABF). In the AGGF, the details are enhanced by optimizing the offset parameter. AGGF-denoised streak images are significantly sharper than those denoised by the GF. Moreover, the AGGF is a fast linear time algorithm achieved by recursively implementing a Gaussian filter kernel. Experimentally, AGGF demonstrates its capacity to preserve edges and thin structures and outperforms the existing bilateral filter and domain transform filter in terms of both visual quality and peak signal-to-noise ratio performance.

  17. Real-time Fluorescence Image-Guided Oncologic Surgery

    PubMed Central

    Mondal, Suman B.; Gao, Shengkui; Zhu, Nan; Liang, Rongguang; Gruev, Viktor; Achilefu, Samuel

    2014-01-01

    Medical imaging plays a critical role in cancer diagnosis and planning. Many of these patients rely on surgical intervention for curative outcomes. This requires a careful identification of the primary and microscopic tumors, and the complete removal of cancer. Although there have been efforts to adapt traditional imaging modalities for intraoperative image guidance, they suffer from several constraints such as large hardware footprint, high operation cost, and disruption of the surgical workflow. Because of the ease of image acquisition, relatively low cost devices and intuitive operation, optical imaging methods have received tremendous interests for use in real-time image-guided surgery. To improve imaging depth under low interference by tissue autofluorescence, many of these applications utilize light in the near-infra red (NIR) wavelengths, which is invisible to human eyes. With the availability of a wide selection of tumor-avid contrast agents, advancements in imaging sensors, electronic and optical designs, surgeons are able to combine different attributes of NIR optical imaging techniques to improve treatment outcomes. The emergence of diverse commercial and experimental image guidance systems, which are in various stages of clinical translation, attests to the potential high impact of intraoperative optical imaging methods to improve speed of oncologic surgery with high accuracy and minimal margin positivity. PMID:25287689

  18. HUBBLE SPACE TELESCOPE Imaging of the Host Galaxies of High-RedshiftRadio-loud Quasars

    NASA Astrophysics Data System (ADS)

    Lehnert, Matthew D.; van Breugel, Wil J. M.; Heckman, Timothy M.; Miley, George K.

    1999-09-01

    We present rest-frame UV and Lyα images of spatially resolved structures (``hosts'') around five high-redshift radio-loud quasars obtained with the WFPC2 camera on the Hubble Space Telescope (HST). The quasars were imaged with the PC1 through the F555W (``V''-band) filter, which at the redshifts of the quasars (2.1imaging surveys. Those had shown that many radio-loud quasars at high redshift have prominent host galaxies that appeared to have properties similar to those of high-redshift radio galaxies. Our HST observations allow a more detailed investigation of quasar host morphologies and a comparison with similar HST studies of radio galaxies by others. Using several methods to measure and quantify the host properties we find that all five quasars are extended and that this ``fuzz'' contains ~5%-40% of the total continuum flux and 15%-65% of the Lyα flux within a radius of about 1.5". The rest-frame UV luminosities of the hosts are log λPλ~11.9-12.5 Lsolar (assuming no internal dust extinction), comparable to the luminous radio galaxies at similar redshifts and a factor 10 higher than both radio-quiet field galaxies at z~2-3 and the most UV-luminous low-redshift starburst galaxies. The Lyα luminosities of the hosts are log LLyα~44.3-44.9 ergs s-1, which are also similar to the those of luminous high-redshift radio galaxies and considerably larger than the Lyα luminosities of high-redshift field galaxies. To generate the Lyα luminosities of the hosts would require roughly a few percent of the total observed ionizing luminosity of the quasar. The UV continuum morphologies of the hosts appear complex and knotty at the relatively high surface brightness levels of our exposures (about 24 V mag arcsec-2). In two quasars we find evidence for foreground galaxies that confuse the

  19. Particle accelerators in the hot spots of radio galaxy 3C 445, imaged with the VLT.

    PubMed

    Prieto, M Almudena; Brunetti, Gianfranco; Mack, Karl-Heinz

    2002-10-04

    Hot spots (HSs) are regions of enhanced radio emission produced by supersonic jets at the tip of the radio lobes of powerful radio sources. Obtained with the Very Large Telescope (VLT), images of the HSs in the radio galaxy 3C 445 show bright knots embedded in diffuse optical emission distributed along the post-shock region created by the impact of the jet into the intergalactic medium. The observations reported here confirm that relativistic electrons are accelerated by Fermi-I acceleration processes in HSs. Furthermore, both the diffuse emission tracing the rims of the front shock and the multiple knots demonstrate the presence of additional continuous re-acceleration processes of electrons (Fermi-II).

  20. Algorithm for constructing a multiring model of radio images of noncoherent radio sources on the basis of the visibility function modulus.

    NASA Astrophysics Data System (ADS)

    Koshovij, V. V.; Lozins'kij, A. B.; Romanishin, I. M.; Romanchev, Yu. V.

    The authors consider the problem of constructing a centrosymmetrical model of radio images of noncoherent radio sources based on the van Cittert-Zernike theorem. They show that one needs only the visibility function modulus determined on the (u,v) plane to construct such a model. They propose to restore radio images as sets of concentric rings using the visibility function measured by the radiointerferometric method with different baselines. An algorithm is given for the determination of the number of rings, their angular radii, and flux densities through the use of the Fourier-Bessel series. The radio image of Cas A was restored from the measurements made with the short-base (up to 2000 D/λ) interferometer URAN-3 at decameter wavelengths (25 MHz), it is in agreement with the results obtained earlier.

  1. HDR Pathological Image Enhancement Based on Improved Bias Field Correction and Guided Image Filter

    PubMed Central

    Zhu, Ganzheng; Li, Siqi; Gong, Shang; Yang, Benqiang; Zhang, Libo

    2016-01-01

    Pathological image enhancement is a significant topic in the field of pathological image processing. This paper proposes a high dynamic range (HDR) pathological image enhancement method based on improved bias field correction and guided image filter (GIF). Firstly, a preprocessing including stain normalization and wavelet denoising is performed for Haematoxylin and Eosin (H and E) stained pathological image. Then, an improved bias field correction model is developed to enhance the influence of light for high-frequency part in image and correct the intensity inhomogeneity and detail discontinuity of image. Next, HDR pathological image is generated based on least square method using low dynamic range (LDR) image, H and E channel images. Finally, the fine enhanced image is acquired after the detail enhancement process. Experiments with 140 pathological images demonstrate the performance advantages of our proposed method as compared with related work. PMID:28116303

  2. Design, implementation and investigation of an image guide-based optical flip-flop array

    NASA Technical Reports Server (NTRS)

    Griffith, P. C.

    1987-01-01

    Presented is the design for an image guide-based optical flip-flop array created using a Hughes liquid crystal light valve and a flexible image guide in a feedback loop. This design is used to investigate the application of image guides as a communication mechanism in numerical optical computers. It is shown that image guides can be used successfully in this manner but mismatch match between the input and output fiber arrays is extremely limiting.

  3. An Amateur's Guide to Observing and Imaging the Heavens

    NASA Astrophysics Data System (ADS)

    Morison, Ian

    2014-06-01

    Foreword; Acknowledgments; Prologue: a tale of two scopes; 1. Telescope and observing fundamentals; 2. Refractors; 3. Binoculars and spotting scopes; 4. The Newtonian telescope and its derivatives; 5. The Cassegrain telescope and its derivatives - Schmidt-Cassegrains and Maksutovs; 6. Telescope maintenance, collimation and star testing; 7. Telescope accessories: finders, eyepieces and bino-viewers; 8. Telescope mounts: alt/az and equatorial with their computerised variants; 9. The art of visual observing; 10. Visual observations of the Moon and planets; 11. Imaging the Moon and planets with DSLRs and web-cams; 12. Observing and imaging the Sun in white light and H-alpha; 13. Observing with an astro-video camera to 'see' faint objects; 14. Deep sky imaging with standard and H-alpha modified DSLR cameras; 15. Deep sky imaging with cooled CCD cameras; 16. Auto-guiding techniques and equipment; 17. Spectral studies of the Sun, stars and galaxies; 18. Improving and enhancing images in Photoshop; Index.

  4. A quality-guided displacement tracking algorithm for ultrasonic elasticity imaging.

    PubMed

    Chen, Lujie; Treece, Graham M; Lindop, Joel E; Gee, Andrew H; Prager, Richard W

    2009-04-01

    Displacement estimation is a key step in the evaluation of tissue elasticity by quasistatic strain imaging. An efficient approach may incorporate a tracking strategy whereby each estimate is initially obtained from its neighbours' displacements and then refined through a localized search. This increases the accuracy and reduces the computational expense compared with exhaustive search. However, simple tracking strategies fail when the target displacement map exhibits complex structure. For example, there may be discontinuities and regions of indeterminate displacement caused by decorrelation between the pre- and post-deformation radio frequency (RF) echo signals. This paper introduces a novel displacement tracking algorithm, with a search strategy guided by a data quality indicator. Comparisons with existing methods show that the proposed algorithm is more robust when the displacement distribution is challenging.

  5. Laplacian forests: semantic image segmentation by guided bagging.

    PubMed

    Lombaert, Herve; Zikic, Darko; Criminisi, Antonio; Ayache, Nicholas

    2014-01-01

    This paper presents a new, efficient and accurate technique for the semantic segmentation of medical images. The paper builds upon the successful random decision forests model and improves on it by modifying the way in which randomness is injected into the tree training process. The contribution of this paper is two-fold. First, we replace the conventional bagging procedure (the uniform sampling of training images) with a guided bagging approach, which exploits the inherent structure and organization of the training image set. This allows the creation of decision trees that are specialized to a specific sub-type of images in the training set. Second, the segmentation of a previously unseen image happens via selection and application of only the trees that are relevant to the given test image. Tree selection is done automatically, via the learned image embedding, with more precisely a Laplacian eigenmap. We, therefore, call the proposed approach Laplacian Forests. We validate Laplacian Forests on a dataset of 256, manually segmented 3D CT scans of patients showing high variability in scanning protocols, resolution, body shape and anomalies. Compared with conventional decision forests, Laplacian Forests yield both higher training efficiency, due to the local analysis of the training image space, as well as higher segmentation accuracy, due to the specialization of the forest to image sub-types.

  6. Three-dimensional imaging and guided surgery for dental implants.

    PubMed

    Ganz, Scott D

    2015-04-01

    Clinicians worldwide are increasingly adopting guided surgical applications for dental implants. Clinicians are becoming more aware of the benefits of proper planning through advanced imaging modalities and interactive treatment planning applications. All aspects of the planning phase are based on sound surgical and restorative fundamentals. As an integral part of the implant team, dental laboratories have now moved from analog to the digital world, providing the necessary support to the new digital workflow.

  7. Novel Image-Guided Management of a Uterine Arteriovenous Malformation

    SciTech Connect

    Przybojewski, Stefan J. Sadler, David J.

    2011-02-15

    The investigators present a novel image-guided embolization, not previously described, of a uterine arteriovenous malformation (AVM) resistant to endovascular management. The uterus was exposed surgically, and Histoacryl (Braun, Fulda, Germany) was injected directly into the nidus using ultrasound guidance and fluoroscopy. The patient had a successful full-term pregnancy after this procedure. This technique may be a useful alternative management strategy in patients with uterine AVM who fail traditional endovascular embolization and who still desire fertility.

  8. Development of Technology for Image-Guided Proton Therapy

    DTIC Science & Technology

    2011-10-01

    therapy including the introduction of on-gantry cone beam CT ( CBCT ). The integration of these techniques, redefined as image guided proton therapy...30/2009  Identify a vendor consortium to develop a solution for CBCT on or near the gantry  Develop a set of hardware and software specifications...for the CBCT system  Develop a timeline and detailed cost breakdown for the CBCT project consistent with the clinical needs of the UPHS/WRAMC

  9. Advanced technologies in image-guided radiation therapy.

    PubMed

    Balter, James M; Cao, Yue

    2007-10-01

    In addition to rapid developments in the use of stationary radiographs and computed tomography scans in treatment rooms, a variety of additional technologies is on the horizon to aid in guided treatment. Some of these (fluoroscopy and tomosynthesis) are variations on the use of existing hardware, whereas others (electromagnetic localization, magnetic resonance imaging) represent significant departures from recently adopted technologic concepts. This review introduces these methods and explores their potential for initial use in guidance.

  10. High-Resolution Radio Imaging of the "Cosmic Hand"

    NASA Astrophysics Data System (ADS)

    Ng, Chi-Yung; Gaensler, Bryan; Slane, Patrick; Harvey-Smith, Lisa

    2012-10-01

    The 'Cosmic Hand' is an extremely complex pulsar wind nebula system powered by the energetic pulsar B1509-58 in supernova remnant G320.4-1.2 (MSH 15-52). Our recent ATCA observations revealed an intriguing jet-like linear feature of 1'-scale surrounding the pulsar. This could be the first known radio jet from a young pulsar, or a synchrotron wisp extending to high latitude. We propose here high-resolution observations to resolve its detailed morphology and to detect any time variability, with the aim to identify its physical nature. Confirming the jet nature could help reveal its launching mechanism and the particle acceleration process, while a wisp can indicate the flow structure beyond the equatorial plane. In either case, this will set an important example to refine our understanding of pulsar wind physics.

  11. Compact instrument for fluorescence image-guided surgery.

    PubMed

    Wang, Xinghua; Bhaumik, Srabani; Li, Qing; Staudinger, V Paul; Yazdanfar, Siavash

    2010-01-01

    Fluorescence image-guided surgery (FIGS) is an emerging technique in oncology, neurology, and cardiology. To adapt intraoperative imaging for various surgical applications, increasingly flexible and compact FIGS instruments are necessary. We present a compact, portable FIGS system and demonstrate its use in cardiovascular mapping in a preclinical model of myocardial ischemia. Our system uses fiber optic delivery of laser diode excitation, custom optics with high collection efficiency, and compact consumer-grade cameras as a low-cost and compact alternative to open surgical FIGS systems. Dramatic size and weight reduction increases flexibility and access, and allows for handheld use or unobtrusive positioning over the surgical field.

  12. Compact instrument for fluorescence image-guided surgery

    NASA Astrophysics Data System (ADS)

    Wang, Xinghua; Bhaumik, Srabani; Li, Qing; Staudinger, V. Paul; Yazdanfar, Siavash

    2010-03-01

    Fluorescence image-guided surgery (FIGS) is an emerging technique in oncology, neurology, and cardiology. To adapt intraoperative imaging for various surgical applications, increasingly flexible and compact FIGS instruments are necessary. We present a compact, portable FIGS system and demonstrate its use in cardiovascular mapping in a preclinical model of myocardial ischemia. Our system uses fiber optic delivery of laser diode excitation, custom optics with high collection efficiency, and compact consumer-grade cameras as a low-cost and compact alternative to open surgical FIGS systems. Dramatic size and weight reduction increases flexibility and access, and allows for handheld use or unobtrusive positioning over the surgical field.

  13. Potential Usefulness of 99mTc-DMSA for Radio-Guided Surgery in Pediatric Renal Dysplasia.

    PubMed

    Familiari, Demetrio; Di Franco, Davide; Cacciaguerra, Sebastiano; Ruggeri, Antonella; Russo, Simona; Fornito, Maria Concetta

    2016-02-01

    We report a case of an ectopic/hypoplastic kidney removed by radio-guided surgery. A 7-year-old girl, with a history of vaginal drainage of urine, underwent renal scintigraphy with Tc-DMSA. SPECT/CT revealed a focal uptake in the pelvis, corresponding to hypoplastic kidney as confirmed by MRI. Based on SPECT/CT findings, the patient underwent laparoscopic surgery, using Tc-DMSA scan to help the surgeon to detect the small ectopic kidney. Intraoperatory histological report confirmed the renal origin of the specimen.

  14. Image-guided minimally invasive percutaneous treatment of spinal metastasis

    PubMed Central

    Yang, Ping-Lin; He, Xi-Jing; Li, Hao-Peng; Zang, Quan-Jin; Wang, Guo-Yu

    2017-01-01

    In order to provide effective options for minimally invasive treatment of spinal metastases, the present study retrospectively evaluated the efficacy and safety of image-guided minimally invasive percutaneous treatment of spinal metastases. Image-guided percutaneous vertebral body enhancement, radiofrequency ablation (RFA) and tumor debulking combined with other methods to strengthen the vertebrae were applied dependent on the indications. Percutaneous vertebroplasty (PVP) was used when vertebral body destruction was simple. In addition, RFA was used in cases where pure spinal epidural soft tissue mass or accessories (spinous process, vertebral plate and vertebral pedicle) were destroyed, but vertebral integrity and stability existed. Tumor debulking (also known as limited RFA) combined with vertebral augmentation were used in cases presenting destruction of the epidural soft tissue mass and accessories, and pathological vertebral fractures. A comprehensive assessment was performed through a standardized questionnaire and indicators including biomechanical stability of the spine, quality of life, neurological status and tumor progression status were assessed during the 6 weeks-6 months follow-up following surgery. After the most suitable treatment was used, the biomechanical stability of the spine was increased, the pain caused by spinal metastases within 6 weeks was significantly reduced, while the daily activities and quality of life were improved. The mean progression-free survival of tumors was 330±54 days, and no associated complications occurred. Therefore, the use of a combination of image-guided PVP, RFA and other methods is safe and effective for the treatment of spinal metastases. PMID:28352355

  15. An image guided small animal stereotactic radiotherapy system

    PubMed Central

    Sha, Hao; Udayakumar, Thirupandiyur S.; Johnson, Perry B.; Dogan, Nesrin; Pollack, Alan; Yang, Yidong

    2016-01-01

    Small animal radiotherapy studies should be performed preferably on irradiators capable of focal tumor irradiation and healthy tissue sparing. In this study, an image guided small animal arc radiation treatment system (iSMAART) was developed which can achieve highly precise radiation targeting through the utilization of onboard cone beam computed tomography (CBCT) guidance. The iSMAART employs a unique imaging and radiation geometry where animals are positioned upright. It consists of a stationary x-ray tube, a stationary flat panel detector, and a rotatable and translational animal stage. System performance was evaluated in regards to imaging, image guidance, animal positioning, and radiation targeting using phantoms and tumor bearing animals. The onboard CBCT achieved good signal, contrast, and sub-millimeter spatial resolution. The iodine contrast CBCT accurately delineated orthotopic prostate tumors. Animal positioning was evaluated with ∼0.3 mm vertical displacement along superior-inferior direction. The overall targeting precision was within 0.4 mm. Stereotactic radiation beams conformal to tumor targets can be precisely delivered from multiple angles surrounding the animal. The iSMAART allows radiobiology labs to utilize an image guided precision radiation technique that can focally irradiate tumors while sparing healthy tissues at an affordable cost. PMID:26958942

  16. Feature-based multiexposure image-sequence fusion with guided filter and image alignment

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Du, Junping; Zhang, Zhenhong

    2015-01-01

    Multiexposure fusion images have a higher dynamic range and reveal more details than a single captured image of a real-world scene. A clear and intuitive feature-based fusion technique for multiexposure image sequences is conceptually proposed. The main idea of the proposed method is to combine three image features [phase congruency (PC), local contrast, and color saturation] to obtain weight maps of the images. Then, the weight maps are further refined using a guided filter which can improve their accuracy. The final fusion result is constructed using the weighted sum of the source image sequence. In addition, for multiexposure image-sequence fusion involving dynamic scenes containing moving objects, ghost artifacts can easily occur if fusion is directly performed. Therefore, an image-alignment method is first used to adjust the input images to correspond to a reference image, after which fusion is performed. Experimental results demonstrate that the proposed method has a superior performance compared to the existing methods.

  17. High Angular Resolution Imaging of Solar Radio Bursts from the Lunar Surface

    NASA Technical Reports Server (NTRS)

    MacDowall, Robert J.; Lazio, Joseph; Bale, Stuart; Burns, Jack O.; Farrell, William M.; Gopalswamy, Nat; Jones, Dayton L.; Kasper, Justin Christophe; Weiler, Kurt

    2012-01-01

    Locating low frequency radio observatories on the lunar surface has a number of advantages, including positional stability and a very low ionospheric radio cutoff. Here, we describe the Radio Observatory on the lunar Surface for Solar studies (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The preferred site is on the lunar near side to simplify the data downlink to Earth. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by measuring the low radio frequency cutoff of the solar radio emissions or background galactic radio emission, measuring the flux, particle mass, and arrival direction of interplanetary and interstellar dust, and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays. Key design requirements on ROLSS include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs below 10 M Hz, essentially unobservable from Earth's surface due to the terrestrial ionospheric cutoff. Resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2 deg at 10 MHz, equivalent to a linear array size of approximately one kilometer. The major components of the ROLSS array are 3 antenna arms, each of 500 m length, arranged in a Y formation, with a central electronics package (CEP) at their intersection. Each antenna arm is a linear strip of polyimide film (e.g., Kapton(TradeMark)) on which 16 single

  18. Symmetric Biomechanically Guided Prone-to-Supine Breast Image Registration.

    PubMed

    Eiben, Björn; Vavourakis, Vasileios; Hipwell, John H; Kabus, Sven; Buelow, Thomas; Lorenz, Cristian; Mertzanidou, Thomy; Reis, Sara; Williams, Norman R; Keshtgar, Mohammed; Hawkes, David J

    2016-01-01

    Prone-to-supine breast image registration has potential application in the fields of surgical and radiotherapy planning, image guided interventions, and multi-modal cancer diagnosis, staging, and therapy response prediction. However, breast image registration of three dimensional images acquired in different patient positions is a challenging problem, due to large deformations induced to the soft breast tissue caused by the change in gravity loading. We present a symmetric, biomechanical simulation based registration framework which aligns the images in a central, virtually unloaded configuration. The breast tissue is modelled as a neo-Hookean material and gravity is considered as the main source of deformation in the original images. In addition to gravity, our framework successively applies image derived forces directly into the unloading simulation in place of a subsequent image registration step. This results in a biomechanically constrained deformation. Using a finite difference scheme avoids an explicit meshing step and enables simulations to be performed directly in the image space. The explicit time integration scheme allows the motion at the interface between chest and breast to be constrained along the chest wall. The feasibility and accuracy of the approach presented here was assessed by measuring the target registration error (TRE) using a numerical phantom with known ground truth deformations, nine clinical prone MRI and supine CT image pairs, one clinical prone-supine CT image pair and four prone-supine MRI image pairs. The registration reduced the mean TRE for the numerical phantom experiment from initially 19.3 to 0.9 mm and the combined mean TRE for all fourteen clinical data sets from 69.7 to 5.6 mm.

  19. Image-guided transorbital procedures with endoscopic video augmentation

    PubMed Central

    DeLisi, Michael P.; Mawn, Louise A.; Galloway, Robert L.

    2014-01-01

    Purpose: Surgical interventions to the orbital space behind the eyeball are limited to highly invasive procedures due to the confined nature of the region along with the presence of several intricate soft tissue structures. A minimally invasive approach to orbital surgery would enable several therapeutic options, particularly new treatment protocols for optic neuropathies such as glaucoma. The authors have developed an image-guided system for the purpose of navigating a thin flexible endoscope to a specified target region behind the eyeball. Navigation within the orbit is particularly challenging despite its small volume, as the presence of fat tissue occludes the endoscopic visual field while the surgeon must constantly be aware of optic nerve position. This research investigates the impact of endoscopic video augmentation to targeted image-guided navigation in a series of anthropomorphic phantom experiments. Methods: A group of 16 surgeons performed a target identification task within the orbits of four skull phantoms. The task consisted of identifying the correct target, indicated by the augmented video and the preoperative imaging frames, out of four possibilities. For each skull, one orbital intervention was performed with video augmentation, while the other was done with the standard image guidance technique, in random order. Results: The authors measured a target identification accuracy of 95.3% and 85.9% for the augmented and standard cases, respectively, with statistically significant improvement in procedure time (Z = −2.044, p = 0.041) and intraoperator mean procedure time (Z = 2.456, p = 0.014) when augmentation was used. Conclusions: Improvements in both target identification accuracy and interventional procedure time suggest that endoscopic video augmentation provides valuable additional orientation and trajectory information in an image-guided procedure. Utilization of video augmentation in transorbital interventions could further minimize

  20. Image fusion and navigation platforms for percutaneous image-guided interventions.

    PubMed

    Rajagopal, Manoj; Venkatesan, Aradhana M

    2016-04-01

    Image-guided interventional procedures, particularly image guided biopsy and ablation, serve an important role in the care of the oncology patient. The need for tumor genomic and proteomic profiling, early tumor response assessment and confirmation of early recurrence are common scenarios that may necessitate successful biopsies of targets, including those that are small, anatomically unfavorable or inconspicuous. As image-guided ablation is increasingly incorporated into interventional oncology practice, similar obstacles are posed for the ablation of technically challenging tumor targets. Navigation tools, including image fusion and device tracking, can enable abdominal interventionalists to more accurately target challenging biopsy and ablation targets. Image fusion technologies enable multimodality fusion and real-time co-displays of US, CT, MRI, and PET/CT data, with navigational technologies including electromagnetic tracking, robotic, cone beam CT, optical, and laser guidance of interventional devices. Image fusion and navigational platform technology is reviewed in this article, including the results of studies implementing their use for interventional procedures. Pre-clinical and clinical experiences to date suggest these technologies have the potential to reduce procedure risk, time, and radiation dose to both the patient and the operator, with a valuable role to play for complex image-guided interventions.

  1. Structure similarity-guided image binarization for automatic segmentation of epidermis surface microstructure images.

    PubMed

    Zou, Y; Lei, B; Dong, F; Xu, G; Sun, S; Xia, P

    2017-01-24

    Partitioning epidermis surface microstructure (ESM) images into skin ridge and skin furrow regions is an important preprocessing step before quantitative analyses on ESM images. Binarization segmentation is a potential technique for partitioning ESM images because of its computational simplicity and ease of implementation. However, even for some state-of-the-art binarization methods, it remains a challenge to automatically segment ESM images, because the grey-level histograms of ESM images have no obvious external features to guide automatic assessment of appropriate thresholds. Inspired by human visual perceptual functions of structural feature extraction and comparison, we propose a structure similarity-guided image binarization method. The proposed method seeks for the binary image that best approximates the input ESM image in terms of structural features. The proposed method is validated by comparing it with two recently developed automatic binarization techniques as well as a manual binarization method on 20 synthetic noisy images and 30 ESM images. The experimental results show: (1) the proposed method possesses self-adaption ability to cope with different images with same grey-level histogram; (2) compared to two automatic binarization techniques, the proposed method significantly improves average accuracy in segmenting ESM images with an acceptable decrease in computational efficiency; (3) and the proposed method is applicable for segmenting practical EMS images. (Matlab code of the proposed method can be obtained by contacting with the corresponding author.).

  2. Compact wearable dual-mode imaging system for real-time fluorescence image-guided surgery

    NASA Astrophysics Data System (ADS)

    Zhu, Nan; Huang, Chih-Yu; Mondal, Suman; Gao, Shengkui; Huang, Chongyuan; Gruev, Viktor; Achilefu, Samuel; Liang, Rongguang

    2015-09-01

    A wearable all-plastic imaging system for real-time fluorescence image-guided surgery is presented. The compact size of the system is especially suitable for applications in the operating room. The system consists of a dual-mode imaging system, see-through goggle, autofocusing, and auto-contrast tuning modules. The paper will discuss the system design and demonstrate the system performance.

  3. gr-MRI: A software package for magnetic resonance imaging using software defined radios

    NASA Astrophysics Data System (ADS)

    Hasselwander, Christopher J.; Cao, Zhipeng; Grissom, William A.

    2016-09-01

    The goal of this work is to develop software that enables the rapid implementation of custom MRI spectrometers using commercially-available software defined radios (SDRs). The developed gr-MRI software package comprises a set of Python scripts, flowgraphs, and signal generation and recording blocks for GNU Radio, an open-source SDR software package that is widely used in communications research. gr-MRI implements basic event sequencing functionality, and tools for system calibrations, multi-radio synchronization, and MR signal processing and image reconstruction. It includes four pulse sequences: a single-pulse sequence to record free induction signals, a gradient-recalled echo imaging sequence, a spin echo imaging sequence, and an inversion recovery spin echo imaging sequence. The sequences were used to perform phantom imaging scans with a 0.5 Tesla tabletop MRI scanner and two commercially-available SDRs. One SDR was used for RF excitation and reception, and the other for gradient pulse generation. The total SDR hardware cost was approximately 2000. The frequency of radio desynchronization events and the frequency with which the software recovered from those events was also measured, and the SDR's ability to generate frequency-swept RF waveforms was validated and compared to the scanner's commercial spectrometer. The spin echo images geometrically matched those acquired using the commercial spectrometer, with no unexpected distortions. Desynchronization events were more likely to occur at the very beginning of an imaging scan, but were nearly eliminated if the user invoked the sequence for a short period before beginning data recording. The SDR produced a 500 kHz bandwidth frequency-swept pulse with high fidelity, while the commercial spectrometer produced a waveform with large frequency spike errors. In conclusion, the developed gr-MRI software can be used to develop high-fidelity, low-cost custom MRI spectrometers using commercially-available SDRs.

  4. gr-MRI: A software package for magnetic resonance imaging using software defined radios.

    PubMed

    Hasselwander, Christopher J; Cao, Zhipeng; Grissom, William A

    2016-09-01

    The goal of this work is to develop software that enables the rapid implementation of custom MRI spectrometers using commercially-available software defined radios (SDRs). The developed gr-MRI software package comprises a set of Python scripts, flowgraphs, and signal generation and recording blocks for GNU Radio, an open-source SDR software package that is widely used in communications research. gr-MRI implements basic event sequencing functionality, and tools for system calibrations, multi-radio synchronization, and MR signal processing and image reconstruction. It includes four pulse sequences: a single-pulse sequence to record free induction signals, a gradient-recalled echo imaging sequence, a spin echo imaging sequence, and an inversion recovery spin echo imaging sequence. The sequences were used to perform phantom imaging scans with a 0.5Tesla tabletop MRI scanner and two commercially-available SDRs. One SDR was used for RF excitation and reception, and the other for gradient pulse generation. The total SDR hardware cost was approximately $2000. The frequency of radio desynchronization events and the frequency with which the software recovered from those events was also measured, and the SDR's ability to generate frequency-swept RF waveforms was validated and compared to the scanner's commercial spectrometer. The spin echo images geometrically matched those acquired using the commercial spectrometer, with no unexpected distortions. Desynchronization events were more likely to occur at the very beginning of an imaging scan, but were nearly eliminated if the user invoked the sequence for a short period before beginning data recording. The SDR produced a 500kHz bandwidth frequency-swept pulse with high fidelity, while the commercial spectrometer produced a waveform with large frequency spike errors. In conclusion, the developed gr-MRI software can be used to develop high-fidelity, low-cost custom MRI spectrometers using commercially-available SDRs.

  5. Respiratory Amplitude Guided 4-Dimensional Magnetic Resonance Imaging

    SciTech Connect

    Hu, Yanle; Caruthers, Shelton D.; Low, Daniel A.; Parikh, Parag J.; Mutic, Sasa

    2013-05-01

    Purpose: To evaluate the feasibility of prospectively guiding 4-dimensional (4D) magnetic resonance imaging (MRI) image acquisition using triggers at preselected respiratory amplitudes to achieve T{sub 2} weighting for abdominal motion tracking. Methods and Materials: A respiratory amplitude-based triggering system was developed and integrated into a commercial turbo spin echo MRI sequence. Initial feasibility tests were performed on healthy human study participants. Four respiratory states, the middle and the end of inhalation and exhalation, were used to trigger 4D MRI image acquisition of the liver. To achieve T{sub 2} weighting, the echo time and repetition time were set to 75 milliseconds and 4108 milliseconds, respectively. Single-shot acquisition, together with parallel imaging and partial k-space imaging techniques, was used to improve image acquisition efficiency. 4D MRI image sets composed of axial or sagittal slices were acquired. Results: Respiratory data measured and logged by the MRI scanner showed that the triggers occurred at the appropriate respiratory levels. Liver motion could be easily observed on both 4D MRI image datasets by sensing either the change of liver in size and shape (axial) or diaphragm motion (sagittal). Both 4D MRI image datasets were T{sub 2}-weighted as expected. Conclusions: This study demonstrated the feasibility of achieving T{sub 2}-weighted 4D MRI images using amplitude-based respiratory triggers. With the aid of the respiratory amplitude-based triggering system, the proposed method is compatible with most MRI sequences and therefore has the potential to improve tumor-tissue contrast in abdominal tumor motion imaging.

  6. High resolution radio imaging study of the Pulsar Wind Nebula MSH 15-52

    NASA Astrophysics Data System (ADS)

    Leung, W.-Y.; Ng, C.-Y.

    2016-06-01

    We present a new high-resolution radio imaging study of the pulsar wind nebula (PWN) MSH 15-52, also dubbed as "the hand of God", with the Australia Telescope Compact Array observations. The system is powered by a young and energetic radio pulsar B1509-58 with high spin down luminosity of E(dot) = 2 x 10^37 erg/s. Previous X-ray images have shown that the PWN has a complex hand-shape morphology extending over 10 pc with features like jets, arc, filaments and enhanced emission knots in the HII region RCW 89. The new 6cm and 3cm radio images show different morphology than the X-ray counterpart. No radio counterpart of the X-ray jet is detected, instead we found enhanced emission in a sheath surrounding the jet. Additional small-scale features including a polarized linear filament next to the pulsar have also been discovered. Our polarisation measurements show that the intrinsic orientation of magnetic field aligns with the sheath. Finally, spectral analysis results indicate a steep spectrum for the system, which is rather unusual among PWNe. Implications of these findings will be discussed. The Australia Telescope Compact Array is part of the Australia Telescope National Facility which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. This work is supported by an ECS grant under HKU 709713P.

  7. A technique for validating image-guided gene therapy

    NASA Astrophysics Data System (ADS)

    Harris, Steven S.; Hallahan, Dennis; Galloway, Robert L., Jr.

    2003-05-01

    Delivery of gene therapy by injection remains governed by a limited diffusion distance. We propose the use of image-guidance to increase the accuracy of delivery, allowing for multiple delivery locations within the tumor. An outcome based approach to validation was developed. We have developed a series of optically tracked devices including an optically tracked syringe used for gene therapy delivery. Experiments were designed to quantify the accuracy in recording known points (fiducial localization error) and delivering a substance to a target within a phantom. The second experiment required the design of a rigid structure with mounted fiducials capable of securely holding an apple. This apparatus was CT scanned and targets in the apple we recorded and inserted in the images. The tracked syringe was guided to the target and a small amount of barium was injected. The apparatus was then re-imaged and the distal points of injections were determined. The mounted fiducials allow the two image sets to be registered and the distance between the targets and injection points to be calculated. This experiment was also performed on a rat carcass. The apple possesses no intrinsic traits possible to help guided the syringe to a known location, thus the validation process remains blind to the user.

  8. VizieR Online Data Catalog: Arp 220 LOFAR radio images at 150MHz (Varenius+, 2016)

    NASA Astrophysics Data System (ADS)

    Varenius, E.; Conway, J. E.; Marti-Vidal, I.; Aalto, S.; Barcos-Munoz, L.; Koenig, S.; Perez-Torres, M. A.; Deller, A. T.; Moldon, J.; Gallagher, J. S.; Yoast-Hull, T. M.; Horellou, C.; Morabito, L. K.; Alberdi, A.; Jackson, N.; Beswick, R.; Carozzi, T. D.; Wucknitz, O.; Ramirez-Olivencia, N.

    2016-07-01

    The 1.4GHz FITS image was obtained by combining data from the Very Large Array (VLA) and the Multi-Element Radio Linked Interferometer Network (MERLIN) arrays. The 150MHz image was obtained from data taken by the International LOFAR telescope, and image using the Multi-Frequency-Synthesis algorithm as implemented in the task CLEAN in CASA 4.5.2 using 2 Taylor terms, which also produced a spectral index map and a spectral index error map. These two FITS images are also included in addition to the continuum image. Using these four FITS images, as well as the CO(1-0) and CO(2-1) maps in Konig et al. (2012ApJ...754...58K) and 6GHz and 33GHz images in Barcos-Munoz et al. (2015. Cat. J/ApJ/799/10), it is possible to reproduce the figures in the paper. (2 data files).

  9. LOFAR tied-array imaging of Type III solar radio bursts

    NASA Astrophysics Data System (ADS)

    Morosan, D. E.; Gallagher, P. T.; Zucca, P.; Fallows, R.; Carley, E. P.; Mann, G.; Bisi, M. M.; Kerdraon, A.; Konovalenko, A. A.; MacKinnon, A. L.; Rucker, H. O.; Thidé, B.; Magdalenić, J.; Vocks, C.; Reid, H.; Anderson, J.; Asgekar, A.; Avruch, I. M.; Bentum, M. J.; Bernardi, G.; Best, P.; Bonafede, A.; Bregman, J.; Breitling, F.; Broderick, J.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Conway, J. E.; de Gasperin, F.; de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Engels, D.; Falcke, H.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Gunst, A. W.; Hassall, T. E.; Hessels, J. W. T.; Hoeft, M.; Hörandel, J.; Horneffer, A.; Iacobelli, M.; Juette, E.; Karastergiou, A.; Kondratiev, V. I.; Kramer, M.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Markoff, S.; McKean, J. P.; Mulcahy, D. D.; Munk, H.; Nelles, A.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pandey, V. N.; Pietka, G.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H.; Scaife, A. M. M.; Schwarz, D.; Serylak, M.; Smirnov, O.; Stappers, B. W.; Stewart, A.; Tagger, M.; Tang, Y.; Tasse, C.; Thoudam, S.; Toribio, C.; Vermeulen, R.; van Weeren, R. J.; Wucknitz, O.; Yatawatta, S.; Zarka, P.

    2014-08-01

    Context. The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio telescopes. Aims: Here, the combined high spatial, spectral, and temporal resolution of the LOw Frequency ARray (LOFAR) was used to study solar Type III radio bursts at 30-90 MHz and their association with CMEs. Methods: The Sun was imaged with 126 simultaneous tied-array beams within ≤5 R⊙ of the solar centre. This method offers benefits over standard interferometric imaging since each beam produces high temporal (~83 ms) and spectral resolution (12.5 kHz) dynamic spectra at an array of spatial locations centred on the Sun. LOFAR's standard interferometric output is currently limited to one image per second. Results: Over a period of 30 min, multiple Type III radio bursts were observed, a number of which were found to be located at high altitudes (~4 R⊙ from the solar center at 30 MHz) and to have non-radial trajectories. These bursts occurred at altitudes in excess of values predicted by 1D radial electron density models. The non-radial high altitude Type III bursts were found to be associated with the expanding flank of a CME. Conclusions: The CME may have compressed neighbouring streamer plasma producing larger electron densities at high altitudes, while the non-radial burst trajectories can be explained by the deflection of radial magnetic fields as the CME expanded in the low corona. Movie associated to Fig. 2 is available in electronic form at http://www.aanda.org

  10. Percutaneous ultrasonography as imaging modality and sampling guide for pulmonologists.

    PubMed

    Stigt, Jos A; Groen, Harry J M

    2014-01-01

    Ultrasound (US) imaging is gradually progressing into common practice in contemporary pulmonology. Its main applications are to determine the presence and amount of pleural effusions and to guide subsequent treatment interventions. Guidelines recommend the use of US for these indications. Training programs are organized and competency levels are formulated. Image guidance with US to obtain specimens for pathologic and/or microbiological analysis is less extensively practiced by pulmonologists but it is an important tool for tumour staging and diagnosing diseases. Lung tumours in contact with the pleural surface, pleural thickenings, mediastinal tumours and chest wall tumours are conceivable indications for pulmonologists to approach with the help of US visualization. Moreover, sampling of chest disease-related extrathoracal lesions may also be regarded as the working field of the pulmonologist. For example, supraclavicular and axillar lymph node metastasis, and also soft tissue and bone metastases, are lesions encountered during dissemination tests. US-guided biopsy provides not only a diagnosis, but also gives information on the stage of disease in sometimes inaccessible primary lesions. US-guided sampling increases diagnostic efficacy and safety and enables very precise performance of fine-needle aspirations as well as tissue core biopsies.

  11. Source Catalog Data from FIRST (Faint Images of the Radio Sky at Twenty-Centimeters)

    DOE Data Explorer

    Becker, Robert H.; Helfand, David J.; White, Richard L.; Gregg, Michael D.; Laurent-Muehleisen, Sally A.

    FIRST, Faint Images of the Radio Sky at Twenty-Centimeters, is a project designed to produce the radio equivalent of the Palomar Observatory Sky Survey over 10,000 square degrees of the North Galactic Cap. Using the National Radio Astronomy Observatory's (NRAO) Very Large Array (VLA) in its B-configuration, the Survey acquired 3-minute snapshots covering a hexagonal grid using 2?7 3-MHz frequency channels centered at 1365 and 1435 MHz. The data were edited, self-calibrated, mapped, and CLEANed using an automated pipeline based largely on routines in the Astronomical Image Processing System (AIPS). A final atlas of maps is produced by coadding the twelve images adjacent to each pointing center. Source catalogs with flux densities and size information are generated from the coadded images also. The 2011 catalog is the latest version and has been tested to ensure reliability and completness. The catalog, generated from the 1993 through 2004 images, contains 816,000 sources and covers more than 9000 square degrees. A specialized search interface for the catalog resides at this website, and the catalog is also available as a compressed ASCII file. The user may also view earlier versions of the source catalog. The FIRST survey area was chosen to coincide with that of the Sloan Digital Sky Survey (SDSS); at the m(v)~24 limit of SDSS, ~50% of the optical counterparts to FIRST sources will be detected.

  12. Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber

    NASA Astrophysics Data System (ADS)

    London, Yosef; Diamandi, Hilel Hagai; Zadok, Avi

    2017-04-01

    An opto-electronic radio-frequency oscillator that is based on forward scattering by the guided acoustic modes of a standard single-mode optical fiber is proposed and demonstrated. An optical pump wave is used to stimulate narrowband, resonant guided acoustic modes, which introduce phase modulation to a co-propagating optical probe wave. The phase modulation is converted to an intensity signal at the output of a Sagnac interferometer loop. The intensity waveform is detected, amplified, and driven back to modulate the optical pump. Oscillations are achieved at a frequency of 319 MHz, which matches the resonance of the acoustic mode that provides the largest phase modulation of the probe wave. Oscillations at the frequencies of competing acoustic modes are suppressed by at least 40 dB. The linewidth of the acoustic resonance is sufficiently narrow to provide oscillations at a single longitudinal mode of the hybrid cavity. Competing longitudinal modes are suppressed by at least 38 dB as well. Unlike other opto-electronic oscillators, no radio-frequency filtering is required within the hybrid cavity. The frequency of oscillations is entirely determined by the fiber opto-mechanics.

  13. Fast Source Camera Identification Using Content Adaptive Guided Image Filter.

    PubMed

    Zeng, Hui; Kang, Xiangui

    2016-03-01

    Source camera identification (SCI) is an important topic in image forensics. One of the most effective fingerprints for linking an image to its source camera is the sensor pattern noise, which is estimated as the difference between the content and its denoised version. It is widely believed that the performance of the sensor-based SCI heavily relies on the denoising filter used. This study proposes a novel sensor-based SCI method using content adaptive guided image filter (CAGIF). Thanks to the low complexity nature of the CAGIF, the proposed method is much faster than the state-of-the-art methods, which is a big advantage considering the potential real-time application of SCI. Despite the advantage of speed, experimental results also show that the proposed method can achieve comparable or better performance than the state-of-the-art methods in terms of accuracy.

  14. [Task sharing with radiotherapy technicians in image-guided radiotherapy].

    PubMed

    Diaz, O; Lorchel, F; Revault, C; Mornex, F

    2013-10-01

    The development of accelerators with on-board imaging systems now allows better target volumes reset at the time of irradiation (image-guided radiotherapy [IGRT]). However, these technological advances in the control of repositioning led to a multiplication of tasks for each actor in radiotherapy and increase the time available for the treatment, whether for radiotherapy technicians or radiation oncologists. As there is currently no explicit regulatory framework governing the use of IGRT, some institutional experiments show that a transfer is possible between radiation oncologists and radiotherapy technicians for on-line verification of image positioning. Initial training for every technical and drafting procedures within institutions will improve audit quality by reducing interindividual variability.

  15. The evolution of image-guided lumbosacral spine surgery

    PubMed Central

    Faulkner, Austin R.; Pasciak, Alexander S.; Bradley, Yong C.

    2015-01-01

    Techniques and approaches of spinal fusion have considerably evolved since their first description in the early 1900s. The incorporation of pedicle screw constructs into lumbosacral spine surgery is among the most significant advances in the field, offering immediate stability and decreased rates of pseudarthrosis compared to previously described methods. However, early studies describing pedicle screw fixation and numerous studies thereafter have demonstrated clinically significant sequelae of inaccurate surgical fusion hardware placement. A number of image guidance systems have been developed to reduce morbidity from hardware malposition in increasingly complex spine surgeries. Advanced image guidance systems such as intraoperative stereotaxis improve the accuracy of pedicle screw placement using a variety of surgical approaches, however their clinical indications and clinical impact remain debated. Beginning with intraoperative fluoroscopy, this article describes the evolution of image guided lumbosacral spinal fusion, emphasizing two-dimensional (2D) and three-dimensional (3D) navigational methods. PMID:25992368

  16. Chimenea and other tools: Automated imaging of multi-epoch radio-synthesis data with CASA

    NASA Astrophysics Data System (ADS)

    Staley, T. D.; Anderson, G. E.

    2015-11-01

    In preparing the way for the Square Kilometre Array and its pathfinders, there is a pressing need to begin probing the transient sky in a fully robotic fashion using the current generation of radio telescopes. Effective exploitation of such surveys requires a largely automated data-reduction process. This paper introduces an end-to-end automated reduction pipeline, AMIsurvey, used for calibrating and imaging data from the Arcminute Microkelvin Imager Large Array. AMIsurvey makes use of several component libraries which have been packaged separately for open-source release. The most scientifically significant of these is chimenea, which implements a telescope-agnostic algorithm for automated imaging of pre-calibrated multi-epoch radio-synthesis data, of the sort typically acquired for transient surveys or follow-up. The algorithm aims to improve upon standard imaging pipelines by utilizing iterative RMS-estimation and automated source-detection to avoid so called 'Clean-bias', and makes use of CASA subroutines for the underlying image-synthesis operations. At a lower level, AMIsurvey relies upon two libraries, drive-ami and drive-casa, built to allow use of mature radio-astronomy software packages from within Python scripts. While targeted at automated imaging, the drive-casa interface can also be used to automate interaction with any of the CASA subroutines from a generic Python process. Additionally, these packages may be of wider technical interest beyond radio-astronomy, since they demonstrate use of the Python library pexpect to emulate terminal interaction with an external process. This approach allows for rapid development of a Python interface to any legacy or externally-maintained pipeline which accepts command-line input, without requiring alterations to the original code.

  17. MO-E-BRD-01: Is Non-Invasive Image-Guided Breast Brachytherapy Good?

    SciTech Connect

    Hiatt, J.

    2015-06-15

    Is Non-invasive Image-Guided Breast Brachytherapy Good? – Jess Hiatt, MS Non-invasive Image-Guided Breast Brachytherapy (NIBB) is an emerging therapy for breast boost treatments as well as Accelerated Partial Breast Irradiation (APBI) using HDR surface breast brachytherapy. NIBB allows for smaller treatment volumes while maintaining optimal target coverage. Considering the real-time image-guidance and immobilization provided by the NIBB modality, minimal margins around the target tissue are necessary. Accelerated Partial Breast Irradiation in brachytherapy: is shorter better? - Dorin Todor, PhD VCU A review of balloon and strut devices will be provided together with the origins of APBI: the interstitial multi-catheter implant. A dosimetric and radiobiological perspective will help point out the evolution in breast brachytherapy, both in terms of devices and the protocols/clinical trials under which these devices are used. Improvements in imaging, delivery modalities and convenience are among the factors driving the ultrashort fractionation schedules but our understanding of both local control and toxicities associated with various treatments is lagging. A comparison between various schedules, from a radiobiological perspective, will be given together with a critical analysis of the issues. to review and understand the evolution and development of APBI using brachytherapy methods to understand the basis and limitations of radio-biological ‘equivalence’ between fractionation schedules to review commonly used and proposed fractionation schedules Intra-operative breast brachytherapy: Is one stop shopping best?- Bruce Libby, PhD. University of Virginia A review of intraoperative breast brachytherapy will be presented, including the Targit-A and other trials that have used electronic brachytherapy. More modern approaches, in which the lumpectomy procedure is integrated into an APBI workflow, will also be discussed. Learning Objectives: To review past and current

  18. LOFAR imaging of Cygnus A - direct detection of a turnover in the hotspot radio spectra

    NASA Astrophysics Data System (ADS)

    McKean, J. P.; Godfrey, L. E. H.; Vegetti, S.; Wise, M. W.; Morganti, R.; Hardcastle, M. J.; Rafferty, D.; Anderson, J.; Avruch, I. M.; Beck, R.; Bell, M. E.; van Bemmel, I.; Bentum, M. J.; Bernardi, G.; Best, P.; Blaauw, R.; Bonafede, A.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Cerrigone, L.; Ciardi, B.; de Gasperin, F.; Deller, A.; Duscha, S.; Engels, D.; Falcke, H.; Fallows, R. A.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J. M.; van Haarlem, M. P.; Heald, G.; Hoeft, M.; Horst, A. J. van der; Iacobelli, M.; Intema, H.; Juette, E.; Karastergiou, A.; Kondratiev, V. I.; Koopmans, L. V. E.; Kuniyoshi, M.; Kuper, G.; van Leeuwen, J.; Maat, P.; Mann, G.; Markoff, S.; McFadden, R.; McKay-Bukowski, D.; Mulcahy, D. D.; Munk, H.; Nelles, A.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pietka, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H. J. A.; Rowlinson, A.; Scaife, A. M. M.; Serylak, M.; Shulevski, A.; Sluman, J.; Smirnov, O.; Steinmetz, M.; Stewart, A.; Swinbank, J.; Tagger, M.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; Vocks, C.; van Weeren, R. J.; Wucknitz, O.; Yatawatta, S.; Zarka, P.

    2016-12-01

    The low-frequency radio spectra of the hotspots within powerful radio galaxies can provide valuable information about the physical processes operating at the site of the jet termination. These processes are responsible for the dissipation of jet kinetic energy, particle acceleration, and magnetic-field generation. Here, we report new observations of the powerful radio galaxy Cygnus A using the Low Frequency Array (LOFAR) between 109 and 183 MHz, at an angular resolution of ˜3.5 arcsec. The radio emission of the lobes is found to have a complex spectral index distribution, with a spectral steepening found towards the centre of the source. For the first time, a turnover in the radio spectrum of the two main hotspots of Cygnus A has been directly observed. By combining our LOFAR imaging with data from the Very Large Array at higher frequencies, we show that the very rapid turnover in the hotspot spectra cannot be explained by a low-energy cut-off in the electron energy distribution, as has been previously suggested. Thermal (free-free) absorption or synchrotron self-absorption models are able to describe the low-frequency spectral shape of the hotspots; however, as with previous studies, we find that the implied model parameters are unlikely, and interpreting the spectra of the hotspots remains problematic.

  19. Characterizing geometric accuracy and precision in image guided gated radiotherapy

    NASA Astrophysics Data System (ADS)

    Tenn, Stephen Edward

    Gated radiotherapy combined with intensity modulated or three-dimensional conformal radiotherapy for tumors in the thorax and abdomen can deliver dose distributions which conform closely to tumor shapes allowing increased tumor dose while sparing healthy tissues. These conformal fields require more accurate and precise placement than traditional fields or tumors may receive suboptimal dose thereby reducing tumor control probability. Image guidance based on four-dimensional computed tomography (4DCT) provides a means to improve accuracy and precision in radiotherapy. The ability of 4DCT to accurately reproduce patient geometry and the ability of image guided gating equipment to position tumors and place fields around them must be characterized in order to determine treatment parameters such as tumor margins. Fiducial based methods of characterizing accuracy and precision of equipment for 4DCT planning and image guided gated radiotherapy (IGGRT) are presented with results for specific equipment. Fiducial markers of known geometric orientation are used to characterize 4DCT image reconstruction accuracy. Accuracy is determined under different acquisition protocols, reconstruction phases, and phantom trajectories. Targeting accuracy of fiducial based image guided gating is assessed by measuring in-phantom field positions for different motions, gating levels and target rotations. Synchronization parameters for gating equipment are also determined. Finally, end-to-end testing is performed to assess overall accuracy and precision of the equipment under controlled conditions. 4DCT limits fiducial geometric distance errors to 2 mm for repeatable target trajectories and to 5 mm for a pseudo-random trajectory. Largest offsets were in the longitudinal direction. If correctly calibrated and synchronized, the IGGRT system tested here can target reproducibly moving tumors with accuracy better than 1.2 mm. Gating level can affect accuracy if target motion is asymmetric about the

  20. A novel radio frequency coil for veterinary magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Meng, Bin; Huang, Kai-Wen; Wang, Wei-Min

    2010-07-01

    In this article, a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM). Good magnetic resonance (MR) images are achieved on a shepherd dog.

  1. Phase contrast portal imaging for image-guided microbeam radiation therapy

    NASA Astrophysics Data System (ADS)

    Umetani, Keiji; Kondoh, Takeshi

    2014-03-01

    High-dose synchrotron microbeam radiation therapy is a unique treatment technique used to destroy tumors without severely affecting circumjacent healthy tissue. We applied a phase contrast technique to portal imaging in preclinical microbeam radiation therapy experiments. Phase contrast portal imaging is expected to enable us to obtain higherresolution X-ray images at therapeutic X-ray energies compared to conventional portal imaging. Frontal view images of a mouse head sample were acquired in propagation-based phase contrast imaging. The phase contrast images depicted edge-enhanced fine structures of the parietal bones surrounding the cerebrum. The phase contrast technique is expected to be effective in bony-landmark-based verification for image-guided radiation therapy.

  2. High Resolution Radio Imaging of the Nucleus of NGC 1275

    NASA Astrophysics Data System (ADS)

    Dhawan, V.; Kellermann, K. I.; Romney, J. D.

    1995-03-01

    We have used the VLBA to observe the nucleus of NGC 1275 at 15 and 43 GHz with angular resolution of 1.0 and 0.3 milliarcsec, respectively. Our observations reveal a bright core and two-sided, more extended structure. The peak intensity of the more prominent, southward-extending jet is located at a distance from the core consistent with apparent subluminal motion at 0.58 c (for H_0 = 50 km s(-1) Mpc(-1) ), continuing since this velocity was first measured (J. D. Romney, W. Alef, I. I. K. Pauliny-Toth, E. Preuss, & K. I. Kellermann 1982, in I. A. U. Symposium No. 97: Extragalactic Radio Sources, p. 291) from primitive maps made in 1979-81. The northward ``counter-jet'' extension is well detected at 15 GHz, with intensity relative to the core intermediate between the two observations at 8.4 GHz (R. C. Walker, J. D. Romney, & J. M. Benson 1994, ApJ, 430, L45) and at 22 GHz (R. C. Vermeulen, A. C. S. Readhead, & D. C. Backer 1994, ApJ, 430, L41) in which this feature was first discovered. In our observations at 43 GHz, the counter-jet is detected, but barely so. Both results are consistent with the model proposed by Vermeulen, Readhead, and Backer, in which the inverted spectrum of this component is a result of free-free absorption in a toroidal or disk-like region. Our 43-GHz observations resolve the core into two bright components separated by about 0.5 milliarcsec in a position angle close to the -9 degrees seen at 10-milliarcsec and indeed at much larger angular scales. A more diffuse structure extends about 1.1 milliarcsec at 45 degrees position angle from the more southerly of the two bright components, and then bends back to the original orientation. This structure is quite different from that seen previously at this frequency. Indications of large position-angle changes in the core on timescales of perhaps six months can be seen in our previous maps at 15, 10.7, and at 8.4 GHz as well.

  3. Image Registration for Targeted MRI-guided Transperineal Prostate Biopsy

    PubMed Central

    Fedorov, Andriy; Tuncali, Kemal; Fennessy, Fiona M.; Tokuda, Junichi; Hata, Nobuhiko; Wells, William M.; Kikinis, Ron; Tempany, Clare M.

    2012-01-01

    Purpose To develop and evaluate image registration methodology for automated re-identification of tumor-suspicious foci from pre-procedural MR exams during MR-guided transperineal prostate core biopsy. Materials and Methods A hierarchical approach for automated registration between planning and intra-procedural T2-weighted prostate MRI was developed and evaluated on the images acquired during 10 consecutive MR-guided biopsies. Registration accuracy was quantified at image-based landmarks and by evaluating spatial overlap for the manually segmented prostate and sub-structures. Registration reliability was evaluated by simulating initial mis-registration and analyzing the convergence behavior. Registration precision was characterized at the planned biopsy targets. Results The total computation time was compatible with a clinical setting, being at most 2 minutes. Deformable registration led to a significant improvement in spatial overlap of the prostate and peripheral zone contours compared to both rigid and affine registration. Average in-slice landmark registration error was 1.3±0.5 mm. Experiments simulating initial mis-registration resulted in an estimated average capture range of 6 mm and an average in-slice registration precision of ±0.3 mm. Conclusion Our registration approach requires minimum user interaction and is compatible with the time constraints of our interventional clinical workflow. The initial evaluation shows acceptable accuracy, reliability and consistency of the method. PMID:22645031

  4. Miniature image guided three-axis scanning and positioning system

    NASA Astrophysics Data System (ADS)

    Avirovik, Dragan; Dave, Digant; Priya, Shashank

    2012-04-01

    We have developed a high precision three axes scanning and positioning system for integration with Multifunctional Image Guided Surgical (MIGS) Platform. The stage integrates three main components: an optical coherence tomography (OCT) probe, laser scalpel and suction cup. The requirements for this stage were to provide scanning area of 400mm2, resolution of less than 10 microns and scanning velocity in the range of 10 - 40 mm/s. The stage was modeled using computer aided design software NX Unigraphics. In addition to the parameters mentioned above, additional boundary conditions for the stage were set as low volume and modularity. Optimized stage model was fabricated by using rapid prototyping technique that integrates low cost stepper motors, threaded rod drive train and a stepper motor controller. The EZ4axis stepper motor controller was able to provide 1/8th microstep resolution control over the motors, which met the criterion desired for the MIGS platform. Integration of computer controlled three-axis stage with MIGS platform provides the opportunity for conducting intricate surgical procedures using remote control or joystick. The device is image guided using the OCT probe and it is able to pin point any location requiring a laser scalpel incision. Due to the scanning capabilities, a high quality threedimensional image of the tissue topography is obtained which allows the surgeon to make a confident decision of where to apply the laser scalpel and make an incision.

  5. Multi-focus image fusion using a guided-filter-based difference image.

    PubMed

    Yan, Xiang; Qin, Hanlin; Li, Jia; Zhou, Huixin; Yang, Tingwu

    2016-03-20

    The aim of multi-focus image fusion technology is to integrate different partially focused images into one all-focused image. To realize this goal, a new multi-focus image fusion method based on a guided filter is proposed and an efficient salient feature extraction method is presented in this paper. Furthermore, feature extraction is primarily the main objective of the present work. Based on salient feature extraction, the guided filter is first used to acquire the smoothing image containing the most sharpness regions. To obtain the initial fusion map, we compose a mixed focus measure by combining the variance of image intensities and the energy of the image gradient together. Then, the initial fusion map is further processed by a morphological filter to obtain a good reprocessed fusion map. Lastly, the final fusion map is determined via the reprocessed fusion map and is optimized by a guided filter. Experimental results demonstrate that the proposed method does markedly improve the fusion performance compared to previous fusion methods and can be competitive with or even outperform state-of-the-art fusion methods in terms of both subjective visual effects and objective quality metrics.

  6. Optoacoustic imaging of the prostate: development toward image-guided biopsy

    NASA Astrophysics Data System (ADS)

    Yaseen, Mohammad A.; Ermilov, Sergey A.; Brecht, Hans-Peter; Su, Richard; Conjusteau, André; Fronheiser, Matthew; Bell, Brent A.; Motamedi, Massoud; Oraevsky, Alexander A.

    2010-03-01

    Optoacoustic (OA) tomography has demonstrated utility in identifying blood-rich malignancies in breast tissue. We describe the development and characterization of a laser OA imaging system for the prostate (LOIS-P). The system consists of a fiber-coupled Q-switched laser operating at 757 nm, a commercial 128-channel ultrasonic probe, a digital signal processor, and software that uses the filtered radial back-projection algorithm for image reconstruction. The system is used to reconstruct OA images of a blood-rich lesion induced in vivo in a canine prostate. OA images obtained in vivo are compared to images acquired using ultrasound, the current gold standard for guiding biopsy of the prostate. Although key structural features such as the urethra could be identified with both imaging techniques, a bloody lesion representing a highly vascularized tumor could only be clearly identified in OA images. The advantages and limitations of both forward and backward illumination modes are also evaluated by collecting OA images of phantoms simulating blood vessels within tissue. System resolution is estimated to be 0.2 mm in the radial direction of the acoustic array. The minimum detectable pressure signal is 1.83 Pa. Our results encourage further development toward a dual-modality OA/ultrasonic system for prostate imaging and image-guided biopsy.

  7. Fast-MICP for frameless image-guided surgery

    SciTech Connect

    Lee, Jiann-Der; Huang, Chung-Hsien; Wang, Sheng-Ta; Lin, Chung-Wei; Lee, Shin-Tseng

    2010-09-15

    Purpose: In image-guided surgery (IGS) systems, image-to-physical registration is critical for reliable anatomical information mapping and spatial guidance. Conventional stereotactic frame-based or fiducial-based approaches provide accurate registration but are not patient-friendly. This study proposes a frameless cranial IGS system that uses computer vision techniques to replace the frame or fiducials with the natural features of the patient. Methods: To perform a cranial surgery with the proposed system, the facial surface of the patient is first reconstructed by stereo vision. Accuracy is ensured by capturing parallel-line patterns projected from a calibrated LCD projector. Meanwhile, another facial surface is reconstructed from preoperative computed tomography (CT) images of the patient. The proposed iterative closest point (ICP)-based algorithm [fast marker-added ICP (Fast-MICP)] is then used to register the two facial data sets, which transfers the anatomical information from the CT images to the physical space. Results: Experimental results reveal that the Fast-MICP algorithm reduces the computational cost of marker-added ICP (J.-D. Lee et al., ''A coarse-to-fine surface registration algorithm for frameless brain surgery,'' in Proceedings of International Conference of the IEEE Engineering in Medicine and Biology Society, 2007, pp. 836-839) to 10% and achieves comparable registration accuracy, which is under 3 mm target registration error (TRE). Moreover, two types of optical-based spatial digitizing devices can be integrated for further surgical navigation. Anatomical information or image-guided surgical landmarks can be projected onto the patient to obtain an immersive augmented reality environment. Conclusion: The proposed frameless IGS system with stereo vision obtains TRE of less than 3 mm. The proposed Fast-MICP registration algorithm reduces registration time by 90% without compromising accuracy.

  8. Mountain Plains Learning Experience Guide: Radio and T.V. Repair. Course: A.C. Circuits.

    ERIC Educational Resources Information Center

    Hoggatt, P.; And Others

    One of four individualized courses included in a radio and television repair curriculum, this course focuses on alternating current relationships and computations, transformers, power supplies, series and parallel resistive-reactive circuits, and series and parallel resonance. The course is comprised of eight units: (1) Introduction to Alternating…

  9. Mountain Plains Learning Experience Guide: Radio and T.V. Repair. Course: D.C. Circuits.

    ERIC Educational Resources Information Center

    Hoggatt, P.; And Others

    One of four individualized courses included in a radio and television repair curriculum, this course deals with the basic electrical properties of current, voltage, resistance, magnetism, mutual induction, and capacitance. The course is comprised of ten units: (1) Current, (2) Voltage, (3) Resistance, (4) Measuring Voltage and Current in Series…

  10. Mountain Plains Learning Experience Guide: Radio and T.V. Repair. Course: Television Repair.

    ERIC Educational Resources Information Center

    Arneson, R.; And Others

    One of four individualized courses included in a radio and television repair, curriculum, this course focuses on trouble-shooting procedures for both black and white and color television equipment. The course is comprised of ten units: (1) Introduction to/and Block Diagrams of Television, (2) Television Audio Section Troubles, (3) Television Video…

  11. Astronomical Images from the Very Large Array (VLA) FIRST Survey Images from the STScI Archive (Faint Images of the Radio Sky at Twenty-cm)

    DOE Data Explorer

    FIRST, Faint Images of the Radio Sky at Twenty-Centimeters was a project designed to produce the radio equivalent of the Palomar Observatory Sky Survey over 10,000 square degrees of the North Galactic Cap. Using the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA) in its B-configuration, the Survey acquired 3-minute snapshots covering a hexagonal grid. The binary data are available in detailed source catalogs, but the full images themselves, developed through special techniques, are also available for public access. Note that the images are fairly large, typically 1150x1550 pixels. Access to the images is simple through the search interface; the images are also available via anonymous ftp at ftp://archive.stsci.edu/pub/vla_first/data. Another convenient way to obtain images is through the FIRST Cutout Server, which allows an image section to be extracted from the coadded image database at a user-specified position. The cutout server is also linked to the FIRST Search Engine, so that the catalog can be searched for sources of interest and then images can be obtained for those objects. All images taken through 2011 are available through the cutout server at http://third.ucllnl.org/cgi-bin/firstcutout.

  12. Image navigation as a means to expand the boundaries of fluorescence-guided surgery

    NASA Astrophysics Data System (ADS)

    Brouwer, Oscar R.; Buckle, Tessa; Bunschoten, Anton; Kuil, Joeri; Vahrmeijer, Alexander L.; Wendler, Thomas; Valdés-Olmos, Renato A.; van der Poel, Henk G.; van Leeuwen, Fijs W. B.

    2012-05-01

    Hybrid tracers that are both radioactive and fluorescent help extend the use of fluorescence-guided surgery to deeper structures. Such hybrid tracers facilitate preoperative surgical planning using (3D) scintigraphic images and enable synchronous intraoperative radio- and fluorescence guidance. Nevertheless, we previously found that improved orientation during laparoscopic surgery remains desirable. Here we illustrate how intraoperative navigation based on optical tracking of a fluorescence endoscope may help further improve the accuracy of hybrid surgical guidance. After feeding SPECT/CT images with an optical fiducial as a reference target to the navigation system, optical tracking could be used to position the tip of the fluorescence endoscope relative to the preoperative 3D imaging data. This hybrid navigation approach allowed us to accurately identify marker seeds in a phantom setup. The multispectral nature of the fluorescence endoscope enabled stepwise visualization of the two clinically approved fluorescent dyes, fluorescein and indocyanine green. In addition, the approach was used to navigate toward the prostate in a patient undergoing robot-assisted prostatectomy. Navigation of the tracked fluorescence endoscope toward the target identified on SPECT/CT resulted in real-time gradual visualization of the fluorescent signal in the prostate, thus providing an intraoperative confirmation of the navigation accuracy.

  13. Image-guided ablative therapies for lung cancer.

    PubMed

    Sharma, Amita; Abtin, Fereidoun; Shepard, Jo-Anne O

    2012-09-01

    Lung cancer is the commonest cause of death in adults. Although the treatment of choice is surgical resection with lobectomy, many patients are nonsurgical candidates because of medical comorbidities. Patients may also have recurrent disease after resection or radiotherapy and some patients refuse surgical options. Image-guided ablation has been recently introduced as a safe, alternative treatment of localized disease in carefully selected patients. This article discusses the principles, technique, and follow-up of the 3 main ablative therapies currently used in the lung, radiofrequency ablation, microwave ablation, and percutaneous cryotherapy.

  14. Image use in field guides and identification keys: review and recommendations

    PubMed Central

    Leggett, Roxanne; Kirchoff, Bruce K.

    2011-01-01

    Background and aims Although illustrations have played an important role in identification keys and guides since the 18th century, their use has varied widely. Some keys lack all illustrations, while others are heavily illustrated. Even within illustrated guides, the way in which images are used varies considerably. Here, we review image use in paper and electronic guides, and establish a set of best practices for image use in illustrated keys and guides. Scope Our review covers image use in both paper and electronic guides, though we only briefly cover apps for mobile devices. With this one exception, we cover the full range of guides, from those that consist only of species descriptions with no keys, to lavishly illustrated technical keys. Emphasis is placed on how images are used, not on the operation of the guides and key, which has been reviewed by others. We only deal with operation when it impacts image use. Main points Few illustrated keys or guides use images in optimal ways. Most include too few images to show taxonomic variation or variation in characters and character states. The use of multiple images allows easier taxon identification and facilitates the understanding of characters. Most images are usually not standardized, making comparison between images difficult. Although some electronic guides allow images to be enlarged, many do not. Conclusions The best keys and guides use standardized images, displayed at sizes that are easy to see and arranged in a standardized manner so that similar images can be compared across species. Illustrated keys and glossaries should contain multiple images for each character state so that the user can judge variation in the state. Photographic backgrounds should not distract from the subject and, where possible, should be of a standard colour. When used, drawings should be prepared by professional botanical illustrators, and clearly labelled. Electronic keys and guides should allow images to be enlarged so that

  15. Deconvolution of images in centimeter-band radio astronomy for the exploitation of new radio interferometers: characterization of non thermal components in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Dabbech, A.

    2015-04-01

    Within the framework of the preparation for the Square Kilometre Array (SKA), that is the world largest radio telescope, new imaging challenges has to be conquered. The data acquired by SKA will have to be processed on real time because of their huge rate. In addition, thanks to its unprecedented resolution and sensitivity, SKA images will have very high dynamic range over wide fields of view. Hence, there is an urgent need for the design of new imaging techniques that are robust and efficient and fully automated. The goal of this thesis is to develop a new technique aiming to reconstruct a model image of the radio sky from the radio observations. The method have been designed to estimate images with high dynamic range with a particular attention to recover faint extended emission usually completely buried in the PSF sidelobes of the brighter sources and the noise. We propose a new approach, based on sparse representations, called MORESANE. The radio sky is assumed to be a summation of sources, considered as atoms of an unknown synthesis dictionary. These atoms are learned using analysis priors from the observed image. Results obtained on realistic simulations show that MORESANE is very promising in the restoration of radio images; it is outperforming the standard tools and very competitive with the newly proposed methods in the literature. MORESANE is also applied on simulations of observations using the SKA1 with the aim to investigate the detectability of the intracluster non thermal component. Our results indicate that these diffuse sources, characterized by very low surface brightness will be investigated up to the epoch of massive cluster formation with the SKA.

  16. Theranostic Multilayer Capsules for Ultrasound Imaging and Guided Drug Delivery.

    PubMed

    Chen, Jun; Ratnayaka, Sithira; Alford, Aaron; Kozlovskaya, Veronika; Liu, Fei; Xue, Bing; Hoyt, Kenneth; Kharlampieva, Eugenia

    2017-03-28

    Despite the accessibility of ultrasound, the clinical potential of ultrasound-active theranostic agents has not been fully realized because it requires combining sufficient imaging contrast, high encapsulation efficiency, and ultrasound-triggered release in one entity. We report on theranostic polymer microcapsules composed of hydrogen-bonded multilayers of tannic acid and poly(N-vinylpyrrolidone) that produce high imaging contrast and deliver the anticancer drug doxorubicin upon low-power diagnostic or high-power therapeutic ultrasound irradiation. These capsules exhibit excellent imaging contrast in both brightness and harmonic modes and show prolonged contrast over six months, unlike commercially available microbubbles. We also demonstrate low-dose gradual and high-dose fast release of doxorubicin from the capsules by diagnostic (∼100 mW/cm(2)) and therapeutic (>10 W/cm(2)) ultrasound irradiation, respectively. We show that the imaging contrast of the capsules can be controlled by varying the number of layers, polymer type (relatively rigid tannic acid versus more flexible poly(methacrylic acid)), and polymer molecular weight. In vitro studies demonstrate that 50% doxorubicin release from ultrasound-treated capsules induces 97% cytotoxicity to MCF-7 human cancer cells, while no cytotoxicity is found without the treatment. Considering the strong ultrasound imaging contrast, high encapsulation efficiency, biocompatibility, and tunable drug release, these microcapsules can be used as theranostic agents for ultrasound-guided chemotherapy.

  17. Fluoroscopic image-guided intervention system for transbronchial localization

    NASA Astrophysics Data System (ADS)

    Rai, Lav; Keast, Thomas M.; Wibowo, Henky; Yu, Kun-Chang; Draper, Jeffrey W.; Gibbs, Jason D.

    2012-02-01

    Reliable transbronchial access of peripheral lung lesions is desirable for the diagnosis and potential treatment of lung cancer. This procedure can be difficult, however, because accessory devices (e.g., needle or forceps) cannot be reliably localized while deployed. We present a fluoroscopic image-guided intervention (IGI) system for tracking such bronchoscopic accessories. Fluoroscopy, an imaging technology currently utilized by many bronchoscopists, has a fundamental shortcoming - many lung lesions are invisible in its images. Our IGI system aligns a digitally reconstructed radiograph (DRR) defined from a pre-operative computed tomography (CT) scan with live fluoroscopic images. Radiopaque accessory devices are readily apparent in fluoroscopic video, while lesions lacking a fluoroscopic signature but identifiable in the CT scan are superimposed in the scene. The IGI system processing steps consist of: (1) calibrating the fluoroscopic imaging system; (2) registering the CT anatomy with its depiction in the fluoroscopic scene; (3) optical tracking to continually update the DRR and target positions as the fluoroscope is moved about the patient. The end result is a continuous correlation of the DRR and projected targets with the anatomy depicted in the live fluoroscopic video feed. Because both targets and bronchoscopic devices are readily apparent in arbitrary fluoroscopic orientations, multiplane guidance is straightforward. The system tracks in real-time with no computational lag. We have measured a mean projected tracking accuracy of 1.0 mm in a phantom and present results from an in vivo animal study.

  18. Dual imaging-guided photothermal/photodynamic therapy using micelles

    PubMed Central

    Guo, Miao; Mao, Huajian; Li, Yanli; Zhu, Aijun; He, Hui; Yang, Hong; Wang, Yangyun; Tian, Xin; Ge, Cuicui; Peng, Qiaoli; Wang, Xiaoyong; Yang, Xiangliang; Chen, Xiaoyuan; Liu, Gang; Chen, Huabing

    2015-01-01

    We report a type of photosensitizer (PS)-loaded micelles integrating cyanine dye as potential theranostic micelles for precise anatomical tumor localization via dual photoacoustic (PA)/near-infrared fluorescent (NIRF) imaging modalities, and simultaneously superior cancer therapy via sequential synergistic photothermal therapy (PTT)/photodynamic therapy (PDT). The micelles exhibit enhanced photostability, cell internalization and tumor accumulation. The dual NIRF/PA imaging modalities of the micelles cause the high imaging contrast and spatial resolution of tumors, which provide precise anatomical localization of the tumor and its inner vasculature for guiding PTT/PDT treatments. Moreover, the micelles can generate severe photothermal damage on cancer cells and destabilization of the lysosomes upon PTT photo-irradiation, which subsequently facilitate synergistic photodynamic injury via PS under PDT treatment. The sequential treatments of PTT/PDT trigger the enhanced cytoplasmic delivery of PS, which contributes to the synergistic anticancer efficacy of PS. Our strategy provides a dual-modal cancer imaging with high imaging contrast and spatial resolution, and subsequent therapeutic synergy of PTT/PDT for potential multimodal theranostic application. PMID:24613048

  19. Guided wave phased array beamforming and imaging in composite plates.

    PubMed

    Yu, Lingyu; Tian, Zhenhua

    2016-05-01

    This paper describes phased array beamforming using guided waves in anisotropic composite plates. A generic phased array algorithm is presented, in which direction dependent guided wave parameters and the energy skew effect are considered. This beamforming at an angular direction is achieved based on the classic delay-and-sum principle by applying phase delays to signals received at array elements and adding up the delayed signals. The phase delays are determined with the goal to maximize the array output at the desired direction and minimize it otherwise. For array characterization, the beam pattern of rectangular grid arrays in composite plates is derived. In addition to the beam pattern, the beamforming factor in terms of wavenumber distribution is defined to provide intrinsic explanations for phased array beamforming. The beamforming and damage detection in a composite plate are demonstrated using rectangular grid arrays made by a non-contact scanning laser Doppler vibrometer. Detection images of the composite plate with multiple surface defects at various directions are obtained. The results show that the guided wave phased array method is a potential effective method for rapid inspection of large composite structures.

  20. Improving the efficiency of image guided brachytherapy in cervical cancer

    PubMed Central

    Franklin, Adrian; Ajaz, Mazhar; Stewart, Alexandra

    2016-01-01

    Brachytherapy is an essential component of the treatment of locally advanced cervical cancers. It enables the dose to the tumor to be boosted whilst allowing relative sparing of the normal tissues. Traditionally, cervical brachytherapy was prescribed to point A but since the GEC-ESTRO guidelines were published in 2005, there has been a move towards prescribing the dose to a 3D volume. Image guided brachytherapy has been shown to reduce local recurrence, and improve survival and is optimally predicated on magnetic resonance imaging. Radiological studies, patient workflow, operative parameters, and intensive therapy planning can represent a challenge to clinical resources. This article explores the ways, in which 3D conformal brachytherapy can be implemented and draws findings from recent literature and a well-developed hospital practice in order to suggest ways to improve the efficiency and efficacy of a brachytherapy service. Finally, we discuss relatively underexploited translational research opportunities. PMID:28115963

  1. FUNCTIONAL NANOPARTICLES FOR MOLECULAR IMAGING GUIDED GENE DELIVERY

    PubMed Central

    Liu, Gang; Swierczewska, Magdalena; Lee, Seulki; Chen, Xiaoyuan

    2010-01-01

    Gene therapy has great potential to bring tremendous changes in treatment of various diseases and disorders. However, one of the impediments to successful gene therapy is the inefficient delivery of genes to target tissues and the inability to monitor delivery of genes and therapeutic responses at the targeted site. The emergence of molecular imaging strategies has been pivotal in optimizing gene therapy; since it can allow us to evaluate the effectiveness of gene delivery noninvasively and spatiotemporally. Due to the unique physiochemical properties of nanomaterials, numerous functional nanoparticles show promise in accomplishing gene delivery with the necessary feature of visualizing the delivery. In this review, recent developments of nanoparticles for molecular imaging guided gene delivery are summarized. PMID:22473061

  2. Navigation concepts for magnetic resonance imaging-guided musculoskeletal interventions.

    PubMed

    Busse, Harald; Kahn, Thomas; Moche, Michael

    2011-08-01

    Image-guided musculoskeletal (MSK) interventions are a widely used alternative to open surgical procedures for various pathological findings in different body regions. They traditionally involve one of the established x-ray imaging techniques (radiography, fluoroscopy, computed tomography) or ultrasound scanning. Over the last decades, magnetic resonance imaging (MRI) has evolved into one of the most powerful diagnostic tools for nearly the whole body and has therefore been increasingly considered for interventional guidance as well.The strength of MRI for MSK applications is a combination of well-known general advantages, such as multiplanar and functional imaging capabilities, wide choice of tissue contrasts, and absence of ionizing radiation, as well as a number of MSK-specific factors, for example, the excellent depiction of soft-tissue tumors, nonosteolytic bone changes, and bone marrow lesions. On the downside, the magnetic resonance-compatible equipment needed, restricted space in the magnet, longer imaging times, and the more complex workflow have so far limited the number of MSK procedures under MRI guidance.Navigation solutions are generally a natural extension of any interventional imaging system, in particular, because powerful hardware and software for image processing have become routinely available. They help to identify proper access paths, provide accurate feedback on the instrument positions, facilitate the workflow in an MRI environment, and ultimately contribute to procedural safety and success.The purposes of this work were to describe some basic concepts and devices for MRI guidance of MSK procedures and to discuss technical and clinical achievements and challenges for some selected implementations.

  3. Faint Radio Sources in the NOAO Bootes Field. VLBA Imaging And Optical Identifications

    SciTech Connect

    Wrobel, J.M.; Taylor, Greg B.; Rector, T.A.; Myers, S.T.; Fassnacht, C.D.; /UC, Davis

    2005-06-13

    As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Booetes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5'' resolution and deconvolved major diameters of less than 3'' at 1.4 GHz. Fifty-five of these faint radio sources were identified with accretion-powered radio galaxies and quasars brighter than 25.5 mag in the optical I band. On VLA scales at 1.4 GHz, a measure of the compactness of the faint sources (the ratio of the peak flux density from FIRST to the integrated flux density from the NVSS catalog) spans the full range of possibilities arising from source-resolution effects. Thirty of the faint radio sources, or 39{sub -7}{sup +9}%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 {sigma} {approx} 2 mJy at 2 mas resolution. The VLBA detections occur through the full range of compactness ratios. The stronger VLBA detections can themselves serve as phase-reference calibrators, boding well for opening up much of the radio sky to VLBA imaging. For the adopted cosmology, the VLBA resolution corresponds to 17 pc or finer. Most VLBA detections are unresolved or slightly resolved but one is diffuse and five show either double or core-jet structures; the properties of these latter six are discussed in detail. Eight VLBA detections are unidentified and fainter than 25.5 mag in the optical I band; their properties are highlighted because they likely mark optically-obscured active nuclei at high redshift.

  4. Transpersonal Psychology: Guiding Image for the Advancement of International Adult Education.

    ERIC Educational Resources Information Center

    Boucouvalas, Marcie

    1984-01-01

    The importance of guiding images is examined, along with analyses of the images of humankind and worldviews previously offered by psychology and adopted by society-at-large. The article focuses on the contribution of transpersonal psychology, the discipline's fourth force, which integrates and extends prior guiding images. (CT)

  5. A Hitchhiker's Guide to Functional Magnetic Resonance Imaging

    PubMed Central

    Soares, José M.; Magalhães, Ricardo; Moreira, Pedro S.; Sousa, Alexandre; Ganz, Edward; Sampaio, Adriana; Alves, Victor; Marques, Paulo; Sousa, Nuno

    2016-01-01

    Functional Magnetic Resonance Imaging (fMRI) studies have become increasingly popular both with clinicians and researchers as they are capable of providing unique insights into brain functions. However, multiple technical considerations (ranging from specifics of paradigm design to imaging artifacts, complex protocol definition, and multitude of processing and methods of analysis, as well as intrinsic methodological limitations) must be considered and addressed in order to optimize fMRI analysis and to arrive at the most accurate and grounded interpretation of the data. In practice, the researcher/clinician must choose, from many available options, the most suitable software tool for each stage of the fMRI analysis pipeline. Herein we provide a straightforward guide designed to address, for each of the major stages, the techniques, and tools involved in the process. We have developed this guide both to help those new to the technique to overcome the most critical difficulties in its use, as well as to serve as a resource for the neuroimaging community. PMID:27891073

  6. [Image-guided radiotherapy: rational, modalities and results].

    PubMed

    de Crevoisier, R; Louvel, G; Cazoulat, G; Leseur, J; Lafond, C; Lahbabi, K; Chira, C; Lagrange, J-L

    2009-01-01

    The objective of Image-Guided Radiotherapy (IGRT) is to take in account the inter- or/and intrafraction anatomic variations (organ motion and deformations) in order to improve treatment accuracy. The IGRT should therefore translate in a clinical benefit the recent advances in both tumor definition thanks to functional imaging, and dose distribution thanks to intensity modulated radiotherapy. The IGRT enables direct or indirect tumor visualization during radiation delivery. If the tumor position does not correspond with the theoretical location of target derived from planning system, the table is moved. In case of important uncertainties related to target deformation, a new planning can be discussed. IGRT is realized by different types of devices which can vary in principle and as well as in their implementation: from LINAC-integrated-kV (or MV)-Cone Beam CTs to helicoidal tomotherapy, Cyberknife and Novalis low-energy stereoscopic imaging system. These techniques led to a more rational choice of Planning Target Volume. Being recently introduced in practice, the clinical results of this technique are still limited. Nevertheless, until so far, IGRT has showed promising results with reports of minimal acute toxicity. This review describes IGRT for various tumor localizations. The dose delivered by on board imaging should be taken in account. A strong quality control is required for safety and proper prospective evaluation of the clinical benefit of IGRT.

  7. Image-guided radiation therapy in lymphoma management

    PubMed Central

    Eng, Tony

    2015-01-01

    Image-guided radiation therapy (IGRT) is a process of incorporating imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), Positron emission tomography (PET), and ultrasound (US) during radiation therapy (RT) to improve treatment accuracy. It allows real-time or near real-time visualization of anatomical information to ensure that the target is in its position as planned. In addition, changes in tumor volume and location due to organ motion during treatment can be also compensated. IGRT has been gaining popularity and acceptance rapidly in RT over the past 10 years, and many published data have been reported on prostate, bladder, head and neck, and gastrointestinal cancers. However, the role of IGRT in lymphoma management is not well defined as there are only very limited published data currently available. The scope of this paper is to review the current use of IGRT in the management of lymphoma. The technical and clinical aspects of IGRT, lymphoma imaging studies, the current role of IGRT in lymphoma management and future directions will be discussed. PMID:26484299

  8. Micro-tattoo guided OCT imaging of site specific inflammation

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Choudhury, Niloy; Samatham, Ravikant V.; Singh, Harvinder; Jacques, Steven L.

    2010-02-01

    Epithelial biologists studying human skin diseases such as cancer formation and psoriasis commonly utilize mouse models to characterize the interplay among cells and intracellular signal transduction pathways that result in programmed changes in gene expression and cellular behaviors. The information obtained from animal models is useful only when phenotypic presentations of disease recapitulate those observed in humans. Excision of tissues followed by histochemical analysis is currently the primary means of establishing the morphological presentation. Non invasive imaging of animal models provides an alternate means to characterize tissue morphology associated with the disease of interest in vivo. While useful, the ability to perform in vivo imaging at different time points in the same tissue location has been a challenge. This information is key to understanding site specific changes as the imaged tissue can now be extracted and analyzed for mRNA expression. We present a method employing a micro-tattoo to guide optical coherence tomography (OCT) imaging of ultraviolet induced inflammation over time in the same tissue locations.

  9. Opinion: Assessing the Barriers to Image Guided Drug Delivery

    PubMed Central

    Lanza, Gregory M.; Moonen, Chrit; Baker, James R.; Chang, Esther; Cheng, Zheng; Grodzinski, Piotr; Ferrara, Katherine; Hynynen, Kullervo; Kelloff, Gary; Koo Lee, Yong-Eun; Patri, Anil K; Sept, David; Schnitzer, Jan E.; Wood, Bradford J.; Zhang, Miqin; Zheng, Gang; Farahani, Keyvan

    2014-01-01

    Imaging has become a cornerstone for medical diagnosis and the guidance of patient management. A new field called Image Guided Drug Delivery (IGDD) now combines the vast potential of the radiological sciences with the delivery of treatment and promises to fulfill the vision of personalized medicine. Whether imaging is used to deliver focused energy to drug-laden particles for enhanced, local drug release around tumors, or it is invoked in the context of nanoparticle-based agents to quantify distinctive biomarkers that could risk-stratify patients for improved targeted drug delivery efficiency, the overarching goal of IGDD is to use imaging to maximize effective therapy in diseased tissues and to minimize systemic drug exposure in order to reduce toxicities. Over the last several years innumerable reports and reviews covering the gamut of IGDD technologies have been published, but inadequate attention has been directed towards identifying and addressing the barriers limiting clinical translation. In this consensus opinion, the opportunities and challenges impacting the clinical realization of IGDD-based personalized medicine were discussed as a panel and recommendations were proffered to accelerate the field forward. PMID:24339356

  10. Prior image constrained scatter correction in cone-beam computed tomography image-guided radiation therapy

    PubMed Central

    Brunner, Stephen; Nett, Brian E; Tolakanahalli, Ranjini; Chen, Guang-Hong

    2012-01-01

    X-ray scatter is a significant problem in cone-beam computed tomography when thicker objects and larger cone angles are used, as scattered radiation can lead to reduced contrast and CT number inaccuracy. Advances have been made in x-ray computed tomography (CT) by incorporating a high quality prior image into the image reconstruction process. In this paper, we extend this idea to correct scatter-induced shading artifacts in cone-beam CT image-guided radiation therapy. Specifically, this paper presents a new scatter correction algorithm which uses a prior image with low scatter artifacts to reduce shading artifacts in cone-beam CT images acquired under conditions of high scatter. The proposed correction algorithm begins with an empirical hypothesis that the target image can be written as a weighted summation of a series of basis images that are generated by raising the raw cone-beam projection data to different powers, and then, reconstructing using the standard filtered backprojection algorithm. The weight for each basis image is calculated by minimizing the difference between the target image and the prior image. The performance of the scatter correction algorithm is qualitatively and quantitatively evaluated through phantom studies using a Varian 2100 EX System with an on-board imager. Results show that the proposed scatter correction algorithm using a prior image with low scatter artifacts can substantially mitigate scatter-induced shading artifacts in both full-fan and half-fan modes. PMID:21258140

  11. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder

    NASA Technical Reports Server (NTRS)

    Haines, D. Mark; Reinisch, Bodo W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N(sub e)) as a function of height (the N(sub e) profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year (1958). The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N(sub e) profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al., 1992), has never been put into space. NASA's 1990 Space Physics Strategy Implementation Study "The NASA Space Physics Program from 1995 to 2010" suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung, 1993). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R(sub e) (Reiff et al., 1994; Calvert et al., 1995). Magnetospheric radio sounding from space will provide remote density measurements of

  12. Radioisotope guided surgery with imaging probe, a hand-held high-resolution gamma camera

    NASA Astrophysics Data System (ADS)

    Soluri, A.; Trotta, C.; Scopinaro, F.; Tofani, A.; D'Alessandria, C.; Pasta, V.; Stella, S.; Massari, R.

    2007-12-01

    Since 1997, our group of Physics together with Nuclear Physicians studies imaging probes (IP), hand-held, high-resolution gamma cameras for radio-guided surgery (RGS). Present work is aimed to verify the usefulness of two updated IP in different surgical operations. Forty patients scheduled for breast cancer sentinel node (SN) biopsy, five patients with nodal recurrence of thyroid cancer, seven patients with parathyroid adenomas, five patients with neuroendocrine tumours (NET), were operated under the guide of IP. We used two different IP with field of view of 1 and 4 in. 2, respectively and intrinsic spatial resolution of about 2 mm. Radioisotopes were 99mTc, 123I and 111In. The 1 in. 2 IP detected SN in all the 40 patients and more than one node in 24, whereas anger camera (AC) failed locating SN in four patients and detected true positive second nodes in only nine patients. The 4 in. 2 IP was used for RGS of thyroid, parathyroid and NETs. It detected eight latero-cervical nodes. In the same patients, AC detected five invaded nodes. Parathyroid adenomas detected by IP were 10 in 7 patients, NET five in five patients. One and 4 in. 2 IPs showed usefulness in all operations. Initial studies on SN biopsy were carried out on small series of patients to validate IP and to demonstrate the effectiveness and usefulness of IP alone or against conventional probes. We propose the use of the IP as control method for legal documentation and surgeon strategy guide before and after lesion(s) removal.

  13. Image-guided radiation therapy for treatment delivery and verification

    NASA Astrophysics Data System (ADS)

    Schubert, Leah Kayomi

    Target conformity and normal tissue sparing provided by modern radiation therapy techniques often result in steep dose gradients, which increase the need for more accurate patient setup and treatment delivery. Image guidance is starting to play a major role in determining the accuracy of treatment setup. A typical objective of image-guided radiation therapy (IGRT) is to minimize differences between planned and delivered treatment by imaging the patient prior to delivery. This step verifies and corrects for patient setup and is referred to as setup verification. This dissertation evaluates the efficacy of daily imaging for setup verification and investigates new uses of IGRT for potential improvements in treatment delivery. The necessity of daily imaging can first be determined by assessing differences in setup corrections between patient groups. Therefore, the first objective of this investigation was to evaluate the application of IGRT for setup verification by quantifying differences in patient positioning for several anatomical disease sites. Detailed analysis of setup corrections for brain, head and neck, lung, and prostate treatments is presented. In this analysis, large setup errors were observed for prostate treatments. Further assessment of prostate treatments was performed, and patient-specific causes of setup errors investigated. Setup corrections are applied via rigid shifts or rotations of the patient or machine, but anatomical deformations occur for which rigid shifts cannot correct. Fortunately, IGRT provides images on which anatomical changes occurring throughout the course of treatment can be detected. From those images, the efficacy of IGRT in ensuring accurate treatment delivery can be evaluated and improved by determining delivered doses and adapting the plan during treatment. The second objective of this dissertation was to explore new applications of IGRT to further improve treatment. By utilizing daily IGRT images, a retrospective analysis of

  14. A Generic and Efficient E-field Parallel Imaging Correlator for Next-Generation Radio Telescopes

    NASA Astrophysics Data System (ADS)

    Thyagarajan, Nithyanandan; Beardsley, Adam P.; Bowman, Judd D.; Morales, Miguel F.

    2017-01-01

    Modern radio telescopes are favouring densely packed array layouts with large numbers of antennas (NA ≳ 1000). Since the complexity of traditional correlators scales as O(N_{A}^2), there will be a steep cost for realizing the full imaging potential of these powerful instruments. Through our generic and efficient E-field Parallel Imaging Correlator (EPIC), we present the first software demonstration of a generalized direct imaging algorithm, namely, the Modular Optimal Frequency Fourier (MOFF) imager. Not only does it bring down the cost for dense layouts to O(N_{A} log _2N_{A}) but can also image from irregular layouts and heterogeneous arrays of antennas. EPIC is highly modular, parallelizable, implemented in object-oriented Python, and publicly available. We have verified the images produced to be equivalent to those from traditional techniques to within a precision set by gridding coarseness. We have also validated our implementation on data observed with the Long Wavelength Array (LWA1). We provide a detailed framework for imaging with heterogeneous arrays and show that EPIC robustly estimates the input sky model for such arrays. Antenna layouts with dense filling factors consisting of a large number of antennas such as LWA, the Square Kilometre Array, Hydrogen Epoch of Reionization Array, and Canadian Hydrogen Intensity Mapping Experiment will gain significant computational advantage by deploying an optimized version of EPIC. The algorithm is a strong candidate for instruments targeting transient searches of Fast Radio Bursts (FRB) as well as planetary and exoplanetary phenomena due to the availability of high-speed calibrated time-domain images and low output bandwidth relative to visibility-based systems.

  15. Image guided constitutive modeling of the silicone brain phantom

    NASA Astrophysics Data System (ADS)

    Puzrin, Alexander; Skrinjar, Oskar; Ozan, Cem; Kim, Sihyun; Mukundan, Srinivasan

    2005-04-01

    The goal of this work is to develop reliable constitutive models of the mechanical behavior of the in-vivo human brain tissue for applications in neurosurgery. We propose to define the mechanical properties of the brain tissue in-vivo, by taking the global MR or CT images of a brain response to ventriculostomy - the relief of the elevated intracranial pressure. 3D image analysis translates these images into displacement fields, which by using inverse analysis allow for the constitutive models of the brain tissue to be developed. We term this approach Image Guided Constitutive Modeling (IGCM). The presented paper demonstrates performance of the IGCM in the controlled environment: on the silicone brain phantoms closely simulating the in-vivo brain geometry, mechanical properties and boundary conditions. The phantom of the left hemisphere of human brain was cast using silicon gel. An inflatable rubber membrane was placed inside the phantom to model the lateral ventricle. The experiments were carried out in a specially designed setup in a CT scanner with submillimeter isotropic voxels. The non-communicative hydrocephalus and ventriculostomy were simulated by consequently inflating and deflating the internal rubber membrane. The obtained images were analyzed to derive displacement fields, meshed, and incorporated into ABAQUS. The subsequent Inverse Finite Element Analysis (based on Levenberg-Marquardt algorithm) allowed for optimization of the parameters of the Mooney-Rivlin non-linear elastic model for the phantom material. The calculated mechanical properties were consistent with those obtained from the element tests, providing justification for the future application of the IGCM to in-vivo brain tissue.

  16. Image-Guided Quantification of Cardioplegia Delivery during Cardiac Surgery

    PubMed Central

    Soltesz, Edward G.; Laurence, Rita G.; De Grand, Alec M.; Cohn, Lawrence H.; Mihaljevic, Tomislav; Frangioni, John V.

    2009-01-01

    Objectives Homogenous distribution of cardioplegia delivered to the myocardium has been identified as an important predictor of post-cardiopulmonary bypass ventricular recovery and function. Presently, a method to determine adequate distribution of cardioplegia in patients during cardiac surgery does not exist. The goal of this study was to evaluate the feasibility of quantifying cardioplegia delivery using a novel, non-invasive optical method. Such a system would permit instantaneous imaging of jeopardized myocardium and allow immediate, intraoperative corrective measures. Methods We have previously developed a portable, intraoperative near-infrared (NIR) fluorescence imaging system for use in large animal cardiac surgery, which simultaneously displays color video and NIR fluorescent images of the surgical field. By introducing exogenous, non-isotopic NIR fluorophores, specific cardiac functions can be visualized in real-time. Results In a cardiopulmonary bypass porcine model, we demonstrate that the FDA-approved intravascular fluorophore indocyanine green (ICG) permits real-time assessment of cardioplegia delivery. ICG was injected into an aortic root and/or transatrial coronary sinus catheter during delivery of cold crystalloid cardioplegia solution. Segmental distribution was immediately noted at the time of injection. In a subset of animals, simulated coronary occlusions resulted in imaging defects consistent with poor cardioplegia delivery and jeopardized myocardium. Videodensitometric analysis was performed on-line to quantify right and left ventricular (RV, LV) distribution. Conclusions We report the development of a novel, non-invasive, intraoperative technique which can easily and safely provide a visual assessment of cardioplegia delivery (antegrade and/or retrograde) and which offers the potential to quantify the relative segmental distribution during cardiac surgical procedures. ULTRAMINI ABSTRACT Intraoperative near-infrared fluorescence imaging is a

  17. Simulation of brain tumor resection in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Fontaine, Kathryn; Hartov, Alex; Roberts, David; Paulsen, Keith

    2011-03-01

    Preoperative magnetic resonance images are typically used for neuronavigation in image-guided neurosurgery. However, intraoperative brain deformation (e.g., as a result of gravitation, loss of cerebrospinal fluid, retraction, resection, etc.) significantly degrades the accuracy in image guidance, and must be compensated for in order to maintain sufficient accuracy for navigation. Biomechanical finite element models are effective techniques that assimilate intraoperative data and compute whole-brain deformation from which to generate model-updated MR images (uMR) to improve accuracy in intraoperative guidance. To date, most studies have focused on early surgical stages (i.e., after craniotomy and durotomy), whereas simulation of more complex events at later surgical stages has remained to be a challenge using biomechanical models. We have developed a method to simulate partial or complete tumor resection that incorporates intraoperative volumetric ultrasound (US) and stereovision (SV), and the resulting whole-brain deformation was used to generate uMR. The 3D ultrasound and stereovision systems are complimentary to each other because they capture features deeper in the brain beneath the craniotomy and at the exposed cortical surface, respectively. In this paper, we illustrate the application of the proposed method to simulate brain tumor resection at three temporally distinct surgical stages throughout a clinical surgery case using sparse displacement data obtained from both the US and SV systems. We demonstrate that our technique is feasible to produce uMR that agrees well with intraoperative US and SV images after dural opening, after partial tumor resection, and after complete tumor resection. Currently, the computational cost to simulate tumor resection can be up to 30 min because of the need for re-meshing and the trial-and-error approach to refine the amount of tissue resection. However, this approach introduces minimal interruption to the surgical workflow

  18. A contrast and registration template for magnetic resonance image data guided dental implant placement

    NASA Astrophysics Data System (ADS)

    Eggers, Georg; Cosgarea, Raluca; Rieker, Marcus; Kress, Bodo; Dickhaus, Hartmut; Mühling, Joachim

    2009-02-01

    An oral imaging template was developed to address the shortcomings of MR image data for image guided dental implant planning and placement. The template was conctructed as a gadolinium filled plastic shell to give contrast to the dentition and also to be accurately re-attachable for use in image guided dental implant placement. The result of segmentation and modelling of the dentition from MR Image data with the template was compared to plaster casts of the dentition. In a phantom study dental implant placement was performed based on MR image data. MR imaging with the contrast template allowed complete representation of the existing dentition. In the phantom study, a commercially available system for image guided dental implant placement was used. Transformation of the imaging contrast template into a surgical drill guide based on the MR image data resulted in pilot burr hole placement with an accuracy of 2 mm. MRI based imaging of the existing dentition for proper image guided planning is possible with the proposed template. Using the image data and the template resulted in less accurate pilot burr hole placement in comparison to CT-based image guided implant placement.

  19. Fluoroscopic tumor tracking for image-guided lung cancer radiotherapy

    NASA Astrophysics Data System (ADS)

    Lin, Tong; Cerviño, Laura I.; Tang, Xiaoli; Vasconcelos, Nuno; Jiang, Steve B.

    2009-02-01

    Accurate lung tumor tracking in real time is a keystone to image-guided radiotherapy of lung cancers. Existing lung tumor tracking approaches can be roughly grouped into three categories: (1) deriving tumor position from external surrogates; (2) tracking implanted fiducial markers fluoroscopically or electromagnetically; (3) fluoroscopically tracking lung tumor without implanted fiducial markers. The first approach suffers from insufficient accuracy, while the second may not be widely accepted due to the risk of pneumothorax. Previous studies in fluoroscopic markerless tracking are mainly based on template matching methods, which may fail when the tumor boundary is unclear in fluoroscopic images. In this paper we propose a novel markerless tumor tracking algorithm, which employs the correlation between the tumor position and surrogate anatomic features in the image. The positions of the surrogate features are not directly tracked; instead, we use principal component analysis of regions of interest containing them to obtain parametric representations of their motion patterns. Then, the tumor position can be predicted from the parametric representations of surrogates through regression. Four regression methods were tested in this study: linear and two-degree polynomial regression, artificial neural network (ANN) and support vector machine (SVM). The experimental results based on fluoroscopic sequences of ten lung cancer patients demonstrate a mean tracking error of 2.1 pixels and a maximum error at a 95% confidence level of 4.6 pixels (pixel size is about 0.5 mm) for the proposed tracking algorithm.

  20. Radio and Hard X-Ray Images of High-Energy Electrons in an X-Class Solar Flare

    NASA Technical Reports Server (NTRS)

    White, S. M.; Krucker, S.; Shibasaki, K.; Yokoyama, T.; Shimojo, M.; Kundu, Mukul R.

    2003-01-01

    We present the first comparison between radio images of high-energy electrons accelerated by a solar flare and images of hard X-rays produced by the same electrons at photon energies above 100 keV. The images indicate that the high-energy X-rays originate at the footpoints of the loops dominating the radio emission. The radio and hard X-ray light curves match each other well and are quantitatively consistent with an origin in a single population of nonthermal electrons with a power-law index of around 4.5-5. The high-frequency radio spectral index suggests a flatter energy spectrum, but this is ruled out by the X-ray spectrum up to 8 MeV.

  1. Hybrid Imaging-Periodicity Search for Radio Pulsars: A Pilot VLA Survey

    NASA Astrophysics Data System (ADS)

    Finn, Molly; Wharton, Robert; Chatterjee, Shami; Cordes, James M.; Kaplan, David L. A.; Burke-Spolaor, Sarah; Crawford, Fronefield; Deller, Adam; Lazio, Joseph; Ransom, Scott M.

    2015-01-01

    Almost all of the ~2300 known pulsars have been discovered using the standard period-dispersion measure (P-DM) search. In a P-DM search, time series intensity data are collected, de-dispersed for a set of trial DMs, and searched for periodic signals usually with frequency-domain algorithms but with fast-folding algorithms for long-period objects. Here we describe a hybrid imaging-periodicity search, an alternate method that uses an imaging survey to select radio point sources as pulsar candidates, followed by a deep P-DM search of these candidates using new or archival data. Since the hybrid search is largely conducted in the imaging domain of time-averaged intensities, it does not suffer reduced sensitivity (as the P-DM method does) when a pulsar signal is heavily modulated by orbital motion, pulse-broadened by scattering, or intermittently emitting (due to large-scale magnetospheric changes, eclipses, etc). As such, the hybrid method is sensitive to systems that are highly selected against in P-DM searches such as compact neutron star binaries, highly scattered millisecond pulsars, and pulsars with spin periods less than a millisecond (should they exist). Interferometric imaging also requires a lower significance threshold for detection than a periodicity search and is more robust against radio-frequency interference. We present preliminary results of a wide-field high dynamic range imaging survey conducted with the Jansky VLA at 1-2 GHz in a pilot program to test the efficacy of a hybrid imaging-periodicity search for radio pulsars in the Galactic plane. The survey region covers four square degrees (Galactic longitudes 32.5-36.5 degrees) using 38 pointings and overlaps with the Arecibo PALFA pulsar survey, which will be used as the periodicity component of our hybrid search. We analyze the observed properties of the 23 known radio pulsars in the survey region and discuss the implications for the selection process needed to narrow the thousands of detected

  2. Superresolution Full-polarimetric Imaging for Radio Interferometry with Sparse Modeling

    NASA Astrophysics Data System (ADS)

    Akiyama, Kazunori; Ikeda, Shiro; Pleau, Mollie; Fish, Vincent L.; Tazaki, Fumie; Kuramochi, Kazuki; Broderick, Avery E.; Dexter, Jason; Mościbrodzka, Monika; Gowanlock, Michael; Honma, Mareki; Doeleman, Sheperd S.

    2017-04-01

    We propose a new technique for radio interferometry to obtain superresolution full-polarization images in all four Stokes parameters using sparse modeling. The proposed technique reconstructs the image in each Stokes parameter from the corresponding full-complex Stokes visibilities by utilizing two regularization functions: the ℓ 1 norm and the total variation (TV) of the brightness distribution. As an application of this technique, we present simulated linear polarization observations of two physically motivated models of M87 with the Event Horizon Telescope. We confirm that ℓ 1+TV regularization can achieve an optimal resolution of ∼25%–30% of the diffraction limit λ /{D}\\max , which is the nominal spatial resolution of a radio interferometer for both the total intensity (i.e., Stokes I) and linear polarizations (i.e., Stokes Q and U). This optimal resolution is better than that obtained from the widely used Cotton–Schwab CLEAN algorithm or from using ℓ 1 or TV regularizations alone. Furthermore, we find that ℓ 1+TV regularization can achieve much better image fidelity in linear polarization than other techniques over a wide range of spatial scales, not only in the superresolution regime, but also on scales larger than the diffraction limit. Our results clearly demonstrate that sparse reconstruction is a useful choice for high-fidelity full-polarimetric interferometric imaging.

  3. Guided Wave Annular Array Sensor Design for Improved Tomographic Imaging

    NASA Astrophysics Data System (ADS)

    Koduru, Jaya Prakash; Rose, Joseph L.

    2009-03-01

    Guided wave tomography for structural health monitoring is fast emerging as a reliable tool for the detection and monitoring of hotspots in a structure, for any defects arising from corrosion, crack growth etc. To date guided wave tomography has been successfully tested on aircraft wings, pipes, pipe elbows, and weld joints. Structures practically deployed are subjected to harsh environments like exposure to rain, changes in temperature and humidity. A reliable tomography system should take into account these environmental factors to avoid false alarms. The lack of mode control with piezoceramic disk sensors makes it very sensitive to traces of water leading to false alarms. In this study we explore the design of annular array sensors to provide mode control for improved structural tomography, in particular, addressing the false alarm potential of water loading. Clearly defined actuation lines in the phase velocity dispersion curve space are calculated. A dominant in-plane displacement point is found to provide a solution to the water loading problem. The improvement in the tomographic images with the annular array sensors in the presence of water traces is clearly illustrated with a series of experiments. An annular array design philosophy for other problems in NDE/SHM is also discussed.

  4. Towards image-guided photodynamic therapy of Glioblastoma

    NASA Astrophysics Data System (ADS)

    Mallidi, Srivalleesha; Huang, Huang-Chiao; Liu, Joyce; Mai, Zhiming; Hasan, Tayyaba

    2013-03-01

    Glioblastoma (GBM) is an aggressive cancer with dismal survival rates and few new treatment options. Fluorescence guided resection of GBM followed by photodynamic therapy (PDT) has shown promise in several chemo- or radiotherapy non-responsive GBM treatments clinically. PDT is an emerging light and photosensitizer (PS) mediated cytotoxic method. However, as with other therapeutic modalities, the outcomes are variable largely due to the nonpersonalization of dose parameters. The variability can be attributed to the differences in heterogeneous photosensitizer accumulation in tumors. Building upon our previous findings on utilizing PS fluorescence for designing tumor-specific PDT dose, we explore the use of photoacoustic imaging, a technique that provides contrast based on the tissue optical absorption properties, to obtain 3D information on the tumoral photosensitizer accumulation. The findings of this study will form the basis for customized photodynamic therapy for glioblastoma and have the potential to serve as a platform for treatment of other cancers.

  5. Concurrent Image Processing Executive (CIPE). Volume 2: Programmer's guide

    NASA Technical Reports Server (NTRS)

    Williams, Winifred I.

    1990-01-01

    This manual is intended as a guide for application programmers using the Concurrent Image Processing Executive (CIPE). CIPE is intended to become the support system software for a prototype high performance science analysis workstation. In its current configuration CIPE utilizes a JPL/Caltech Mark 3fp Hypercube with a Sun-4 host. CIPE's design is capable of incorporating other concurrent architectures as well. CIPE provides a programming environment to applications' programmers to shield them from various user interfaces, file transactions, and architectural complexities. A programmer may choose to write applications to use only the Sun-4 or to use the Sun-4 with the hypercube. A hypercube program will use the hypercube's data processors and optionally the Weitek floating point accelerators. The CIPE programming environment provides a simple set of subroutines to activate user interface functions, specify data distributions, activate hypercube resident applications, and to communicate parameters to and from the hypercube.

  6. Image-guided surgical microscope with mounted minitracker.

    PubMed

    Caversaccio, M; Garcia-Giraldez, J; Gonzalez-Ballester, M; Marti, G

    2007-02-01

    A new image-guided microscope using augmented reality overlays has been developed. Unlike other systems, the novelty of our design consists in mounting a precise mini and low-cost tracker directly on the microscope to track the motion of the surgical tools and the patient. Correctly scaled cut-views of the pre-operative computed tomography (CT) stack can be displayed on the overlay, orthogonal to the optical view or even including the direction of a clinical tool. Moreover, the system can manage three-dimensional models for tumours or bone structures and allows interaction with them using virtual tools, showing trajectories and distances. The mean error of the overlay was 0.7 mm. Clinical accuracy has shown results of 1.1-1.8 mm.

  7. The Radio Amateur's Handbook.

    ERIC Educational Resources Information Center

    Blakeslee, Douglas, Ed.

    The objectives of this basic reference work for the radio amateur are to present radio theory and practice in terms of application and to reflect both the fundamentals and the rapidly-advancing technology of radio communications so that the radio amateur will have a guide to what is practical, meaningful, proven, and useful. Twenty-three chapters…

  8. Radio Induced Fluorescence (RIF) Imaging Of E-region Quasi-periodic Structures

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.

    The horizontal structure of sporadic-E layers has been imaged using artificial airglow excited by high power radio waves. In January 1998, the HF facility at Arecibo, Puerto Rico beamed a 80 MW signal upward at 3.175 MHz. The beam reflected in the E- region near 120 km altitude to excite green-line emissions at 557.7 nm. Ground based images showed quasi-periodic structures with periods near 2 and 10 km. These struc- tures been interpreted as being produced by Kelvin-Helmholtz (K-H) instabilities in the neutral atmosphere. The excitation of radio induced fluorescence (RIF) emissions has been studied with both one-dimensional and two-dimensional computer simulations of the conversion of electromagnetic waves into electron plasma waves. The steep gradients on the bottomside of the E-layer provide conditions for efficient mode conversion. The re- sulting Langmuir waves accelerate electrons to energies between 2 and 10 eV. These suprathermal electrons collide with oxygen atoms to produce green-line emissions. The optical glow only occurs in the parts of the E-region where the plamsa is dense enough to reflect the 3.175 MHz radio waves. Results of the E-layer observations using the RIF technique have shown horizontal stuctures that are most likely produced by the K-H instability. A numerical model has been generated to demonstrate the effects of neutral wind shears on the E-region structures. The model includes the effects of both speed-shear and turning shear dy- namics. The results of the numerical model are used to suggest future research using high-power radio wave to study the ion dynamics of the lower thermosphere.

  9. Airborne laser-guided imaging spectroscopy to map forest trait diversity and guide conservation.

    PubMed

    Asner, G P; Martin, R E; Knapp, D E; Tupayachi, R; Anderson, C B; Sinca, F; Vaughn, N R; Llactayo, W

    2017-01-27

    Functional biogeography may bridge a gap between field-based biodiversity information and satellite-based Earth system studies, thereby supporting conservation plans to protect more species and their contributions to ecosystem functioning. We used airborne laser-guided imaging spectroscopy with environmental modeling to derive large-scale, multivariate forest canopy functional trait maps of the Peruvian Andes-to-Amazon biodiversity hotspot. Seven mapped canopy traits revealed functional variation in a geospatial pattern explained by geology, topography, hydrology, and climate. Clustering of canopy traits yielded a map of forest beta functional diversity for land-use analysis. Up to 53% of each mapped, functionally distinct forest presents an opportunity for new conservation action. Mapping functional diversity advances our understanding of the biosphere to conserve more biodiversity in the face of land use and climate change.

  10. Deep multi-frequency radio imaging in the Lockman Hole using the GMRT and VLA - I. The nature of the sub-mJy radio population

    NASA Astrophysics Data System (ADS)

    Ibar, Edo; Ivison, R. J.; Biggs, A. D.; Lal, D. V.; Best, P. N.; Green, D. A.

    2009-07-01

    In the run up to routine observations with the upcoming generation of radio facilities, the nature of sub-mJy radio population has been hotly debated. Here, we describe multi-frequency data designed to probe the emission mechanism that dominates in these faint radio sources. Our analysis is based on observations of the Lockman Hole using the Giant Metrewave Radio Telescope (GMRT) - the deepest 610-MHz imaging yet reported - together with 1.4-GHz imaging from the Very Large Array (VLA), well matched in resolution and sensitivity to the GMRT data: σ610MHz ~ 15μJybeam-1, σ1.4GHz ~ 6μJybeam-1, full width at half-maximum (FWHM) ~ 5arcsec. The GMRT and VLA data are cross-matched to obtain the radio spectral indices for the faint radio emitters. Statistical analyses show no clear evolution for the median spectral index, α610MHz1.4GHz (where Sν ~ να), as a function of flux density. α610MHz1.4GHz is found to be approximately -0.6 to -0.7, based on an almost unbiased 10σ criterion, down to a flux level of S1.4GHz >~100μJy. The fraction of inverted spectrum sources (α610MHz1.4GHz > 0) is less than 10 per cent. The results suggest that the most prevalent emission mechanism in the sub-mJy regime is optically thin synchrotron, ruling out a dominant flat spectrum or ultra-steep spectrum radio population. The spectral index distribution has a significant scatter, Δα ~ 0.4-0.5, which suggests a mixture of different populations at all flux levels. Spectroscopic classification of radio sources with X-ray emission has allowed us to estimate that the fraction of radio-quiet active galactic nuclei (AGN) at 30μJy <~ S1.4GHz <300μJy is roughly 25 +/- 10 per cent, suggesting that star-forming galaxies dominate the sub-mJy regime.

  11. Systematic measurements of whole-body imaging dose distributions in image-guided radiation therapy

    SciTech Connect

    Haelg, Roger A.; Besserer, Juergen; Schneider, Uwe

    2012-12-15

    Purpose: The full benefit of the increased precision of contemporary treatment techniques can only be exploited if the accuracy of the patient positioning is guaranteed. Therefore, more and more imaging modalities are used in the process of the patient setup in clinical routine of radiation therapy. The improved accuracy in patient positioning, however, results in additional dose contributions to the integral patient dose. To quantify this, absorbed dose measurements from typical imaging procedures involved in an image-guided radiation therapy treatment were measured in an anthropomorphic phantom for a complete course of treatment. The experimental setup, including the measurement positions in the phantom, was exactly the same as in a preceding study of radiotherapy stray dose measurements. This allows a direct combination of imaging dose distributions with the therapy dose distribution. Methods: Individually calibrated thermoluminescent dosimeters were used to measure absorbed dose in an anthropomorphic phantom at 184 locations. The dose distributions from imaging devices used with treatment machines from the manufacturers Accuray, Elekta, Siemens, and Varian and from computed tomography scanners from GE Healthcare were determined and the resulting effective dose was calculated. The list of investigated imaging techniques consisted of cone beam computed tomography (kilo- and megavoltage), megavoltage fan beam computed tomography, kilo- and megavoltage planar imaging, planning computed tomography with and without gating methods and planar scout views. Results: A conventional 3D planning CT resulted in an effective dose additional to the treatment stray dose of less than 1 mSv outside of the treated volume, whereas a 4D planning CT resulted in a 10 times larger dose. For a daily setup of the patient with two planar kilovoltage images or with a fan beam CT at the TomoTherapy unit, an additional effective dose outside of the treated volume of less than 0.4 mSv and 1

  12. Wavelet-based compression with ROI coding support for mobile access to DICOM images over heterogeneous radio networks.

    PubMed

    Maglogiannis, Ilias; Doukas, Charalampos; Kormentzas, George; Pliakas, Thomas

    2009-07-01

    Most of the commercial medical image viewers do not provide scalability in image compression and/or region of interest (ROI) encoding/decoding. Furthermore, these viewers do not take into consideration the special requirements and needs of a heterogeneous radio setting that is constituted by different access technologies [e.g., general packet radio services (GPRS)/ universal mobile telecommunications system (UMTS), wireless local area network (WLAN), and digital video broadcasting (DVB-H)]. This paper discusses a medical application that contains a viewer for digital imaging and communications in medicine (DICOM) images as a core module. The proposed application enables scalable wavelet-based compression, retrieval, and decompression of DICOM medical images and also supports ROI coding/decoding. Furthermore, the presented application is appropriate for use by mobile devices activating in heterogeneous radio settings. In this context, performance issues regarding the usage of the proposed application in the case of a prototype heterogeneous system setup are also discussed.

  13. Modeling log-compressed ultrasound images for radio frequency signal recovery.

    PubMed

    Seabra, José; Sanches, João

    2008-01-01

    This paper presents an algorithm for recovering the radio frequency (RF) signal provided by the ultrasound probe from the log-compressed ultrasound images displayed in ultrasound equipment. Commercial ecographs perform nonlinear image compression to reduce the dynamic range of the Ultrasound (US) signal in order to improve image visualization. Moreover, the clinician may adjust other parameters, such as brightness, gain and contrast, to improve image quality of a given anatomical detail. These operations significantly change the statistical distribution of the original RF raw signal, which is assumed, based on physical considerations on the signal formation process, to be Rayleigh distributed. Therefore, the image pixels are no longer Rayleigh distributed and the RF signal is not usually available in the common ultrasound equipment. For statistical data processing purposes, more important than having "good looking" images, it is important to have realistic models to describe the data. In this paper, a nonlinear compression parametric function is used to model the pre-processed image in order to recover the original RF image as well the contrast and brightness parameters. Tests using synthetic and real data and statistical measures such as the Kolmogorov-Smirnov and Kullback-Leibler divergences are used to assess the results. It is shown that the proposed estimation model clearly represents better the observed data than by taking the general assumption of the data being modeled by a Rayleigh distribution.

  14. Fluorescent supramolecular micelles for imaging-guided cancer therapy

    NASA Astrophysics Data System (ADS)

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-02-01

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth

  15. Radio Science

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Radio science experiments use electromagnetic waves to probe or study the solar system. Three major research areas were identified within this discipline: radio astronomy, radar astronomy, and celestial mechanics. Radio astronomy (or radiometry) is the detection and measurement of naturally produced radio frequency emissions. Sources include surfaces, atmospheres, rings, and plasmas. Radar astronomy is the observation of man-made signals after their interaction with a target. Both imaging and non-imaging results. Celestial mechanics includes all studies related to the motions of (and gravity fields of) bodies within the solar system. These should not be considered rigid separations, but aid in the discussion of the data sets.

  16. Intraoperative Imaging-Guided Cancer Surgery: From Current Fluorescence Molecular Imaging Methods to Future Multi-Modality Imaging Technology

    PubMed Central

    Chi, Chongwei; Du, Yang; Ye, Jinzuo; Kou, Deqiang; Qiu, Jingdan; Wang, Jiandong; Tian, Jie; Chen, Xiaoyuan

    2014-01-01

    Cancer is a major threat to human health. Diagnosis and treatment using precision medicine is expected to be an effective method for preventing the initiation and progression of cancer. Although anatomical and functional imaging techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role for accurate preoperative diagnostics, for the most part these techniques cannot be applied intraoperatively. Optical molecular imaging is a promising technique that provides a high degree of sensitivity and specificity in tumor margin detection. Furthermore, existing clinical applications have proven that optical molecular imaging is a powerful intraoperative tool for guiding surgeons performing precision procedures, thus enabling radical resection and improved survival rates. However, detection depth limitation exists in optical molecular imaging methods and further breakthroughs from optical to multi-modality intraoperative imaging methods are needed to develop more extensive and comprehensive intraoperative applications. Here, we review the current intraoperative optical molecular imaging technologies, focusing on contrast agents and surgical navigation systems, and then discuss the future prospects of multi-modality imaging technology for intraoperative imaging-guided cancer surgery. PMID:25250092

  17. Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging.

    PubMed

    Hu, Cheng; Liu, Changjiang; Wang, Rui; Zeng, Tao

    2016-05-07

    Forward scatter radar (FSR), as a specially configured bistatic radar, is provided with the capabilities of target recognition and classification by the Shadow Inverse Synthetic Aperture Radar (SISAR) imaging technology. This paper mainly discusses the reconstruction of radio holographic signal (RHS), which is an important procedure in the signal processing of FSR SISAR imaging. Based on the analysis of signal characteristics, the method for RHS reconstruction is improved in two parts: the segmental Hilbert transformation and the reconstruction of mainlobe RHS. In addition, a quantitative analysis of the method's applicability is presented by distinguishing between the near field and far field in forward scattering. Simulation results validated the method's advantages in improving the accuracy of RHS reconstruction and imaging.

  18. Improved Reconstruction of Radio Holographic Signal for Forward Scatter Radar Imaging

    PubMed Central

    Hu, Cheng; Liu, Changjiang; Wang, Rui; Zeng, Tao

    2016-01-01

    Forward scatter radar (FSR), as a specially configured bistatic radar, is provided with the capabilities of target recognition and classification by the Shadow Inverse Synthetic Aperture Radar (SISAR) imaging technology. This paper mainly discusses the reconstruction of radio holographic signal (RHS), which is an important procedure in the signal processing of FSR SISAR imaging. Based on the analysis of signal characteristics, the method for RHS reconstruction is improved in two parts: the segmental Hilbert transformation and the reconstruction of mainlobe RHS. In addition, a quantitative analysis of the method’s applicability is presented by distinguishing between the near field and far field in forward scattering. Simulation results validated the method’s advantages in improving the accuracy of RHS reconstruction and imaging. PMID:27164114

  19. Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries

    PubMed Central

    Devlin, Steven M.; Hurtig, Mark B.; Waldman, Stephen D.; Rudan, John F.; Bardana, Davide D.; Stewart, A. James

    2013-01-01

    Objective: Autologous osteochondral cartilage repair is a valuable reconstruction option for cartilage defects, but the accuracy to harvest and deliver osteochondral grafts remains problematic. We investigated whether image-guided methods (optically guided and template guided) can improve the outcome of these procedures. Design: Fifteen sheep were operated to create traumatic chondral injuries in each knee. After 4 months, the chondral defect in one knee was repaired using (a) conventional approach, (b) optically guided method, or (c) template-guided method. For both image-guided groups, harvest and delivery sites were preoperatively planned using custom-made software. During optically guided surgery, instrument position and orientation were tracked and superimposed onto the surgical plan. For the template-guided group, plastic templates were manufactured to allow an exact fit between template and the joint anatomy. Cylindrical holes within the template guided surgical tools according to the plan. Three months postsurgery, both knees were harvested and computed tomography scans were used to compare the reconstructed versus the native pre-injury joint surfaces. For each repaired defect, macroscopic (International Cartilage Repair Society [ICRS]) and histological repair (ICRS II) scores were assessed. Results: Three months after repair surgery, both image-guided surgical approaches resulted in significantly better histology scores compared with the conventional approach (improvement by 55%, P < 0.02). Interestingly, there were no significant differences found in cartilage surface reconstruction and macroscopic scores between the image-guided and the conventional surgeries. PMID:26069658

  20. High contrast optical imaging methods for image guided laser ablation of dental caries lesions

    NASA Astrophysics Data System (ADS)

    LaMantia, Nicole R.; Tom, Henry; Chan, Kenneth H.; Simon, Jacob C.; Darling, Cynthia L.; Fried, Daniel

    2014-02-01

    Laser based methods are well suited for automation and can be used to selectively remove dental caries to minimize the loss of healthy tissues and render the underlying enamel more resistant to acid dissolution. The purpose of this study was to determine which imaging methods are best suited for image-guided ablation of natural non-cavitated carious lesions on occlusal surfaces. Multiple caries imaging methods were compared including near-IR and visible reflectance and quantitative light fluorescence (QLF). In order for image-guided laser ablation to be feasible, chemical and physical modification of tooth surfaces due to laser irradiation cannot greatly reduce the contrast between sound and demineralized dental hard tissues. Sound and demineralized surfaces of 48 extracted human molar teeth with non-cavitated lesions were examined. Images were acquired before and after laser irradiation using visible and near-IR reflectance and QLF at several wavelengths. Polarization sensitive-optical coherence tomography was used to confirm that lesions were present. The highest contrast was attained at 1460-nm and 1500-1700-nm, wavelengths coincident with higher water absorption. The reflectance did not decrease significantly after laser irradiation for those wavelengths.

  1. Forward modeling of radio imaging (RIM) data with the Comsol RF module

    NASA Astrophysics Data System (ADS)

    Li, Yongxing; Smith, Richard S.

    2015-12-01

    Radio imaging method (RIM) is an electromagnetic (EM) tomographic method, which can be applied to image the electrical properties (principally the conductivity) in the plane defined by two boreholes. RIM employs the EM waves at radio frequencies between 100 kHz and 10 MHz, and the manner that these waves propagate around subsurface ore bodies has not been studied thoroughly. We studied the wave propagation using the finite element modeling (FEM) algorithm as implemented in the Comsol RF module. An appropriate element size is quantified by comparing the Comsol modeling results of 6 types of element sizes at 4 frequencies with the analytical solution in the homogeneous whole space. The FEM model data with 5 elements per wavelength have errors less than 5%; 7-8 elements per wavelength provide the errors around 1%; when there are 10 elements per wavelength, the errors are less than 1%. Comparison studies for more complicated models with anomalous conductivity structures show that the Comsol modeling results are consistent with results derived from analytical solutions, finite-difference time-domain methods and integral equations. To illustrate the flexibility of the Comsol method for RIM modeling, we provide an example with two moderately conductive bodies between boreholes. Receiver profiles and a relative variation map show that when the conductive bodies are two wavelengths away from the source, the EM wave attenuation and reflection by the conductive bodies can be observed. The amplitude tomography of the model data reveals that with the SIRT algorithm, the location of the conductive anomalies can be reconstructed successfully, although, some limitations exist such as low resolution, incorrect conductivity estimation, and some artifacts. From our work, we conclude that Comsol modeling is helpful to study radio wave propagation and imaging methods.

  2. High-Resolution X-Ray Imaging of Colliding Radio-Jet Galaxies

    NASA Technical Reports Server (NTRS)

    Born, Kirk D.; Whitmore, Brad

    1996-01-01

    We received ROSAT data for four program objects:3C31,3C278,3C449,and NGC1044. The first three sources were observed with the ROSAT HRI instrument. Our plan was to use the HRI to image the hot gas distribution in a few pairs of strongly disturbed interacting elliptical galaxies which are also strong radio sources having a bent-jet source morphology. The PSPC was used for NGC1044 in order to obtain a flux measurement to use in planning future High Resolution Imager (HRI) observations of that source. Though we never requested such HRI observations of NGC1044, others have used those archival PSPC data from our project for other research projects and analyses. The goal of the program was to elucidate the detailed distribution of hot gas into which the jets flow. The X-ray data were consequently analyzed in conjunction with existing VLA radio maps, optical broad-band and H-alpha Charge Couple device (CCD) images, and optical kinematic data to constrain models for the propagation of ballistic jets in interacting galaxies. We were able to test and validate the claimed causal connection between tidal interaction, the presence of gas, and the onset of activity in galaxies. The full multi-wavelength multi-observatory analyses described here are still on-going and will be published in the future. Because of the relevance of this research to on-going work in the field of active galaxies, the grant was used to support travel to several scientific meetings where our x-ray analysis, numerical modeling, and related radio results were presented and discussed.

  3. Fluorescent supramolecular micelles for imaging-guided cancer therapy.

    PubMed

    Sun, Mengmeng; Yin, Wenyan; Dong, Xinghua; Yang, Wantai; Zhao, Yuliang; Yin, Meizhen

    2016-03-07

    A novel smart fluorescent drug delivery system composed of a perylene diimide (PDI) core and block copolymer poly(d,l-lactide)-b-poly(ethyl ethylene phosphate) is developed and named as PDI-star-(PLA-b-PEEP)8. The biodegradable PDI-star-(PLA-b-PEEP)8 is a unimolecular micelle and can self-assemble into supramolecular micelles, called as fluorescent supramolecular micelles (FSMs), in aqueous media. An insoluble drug camptothecin (CPT) can be effectively loaded into the FSMs and exhibits pH-responsive release. Moreover, the FSMs with good biocompatibility can also be employed as a remarkable fluorescent probe for cell labelling because the maximum emission of PDI is beneficial for bio-imaging. The flow cytometry and confocal laser scanning microscopy analysis demonstrate that the micelles are easily endocytosed by cancer cells. In vitro and in vivo tumor growth-inhibitory studies reveal a better therapeutic effect of FSMs after CPT encapsulation when compared with the free CPT drug. The multifunctional FSM nanomedicine platform as a nanovehicle has great potential for fluorescence imaging-guided cancer therapy.

  4. Comparison of image-guided radiotherapy technologies for prostate cancer.

    PubMed

    Das, Satya; Liu, Tian; Jani, Ashesh B; Rossi, Peter; Shelton, Joseph; Shi, Zheng; Khan, Mohammad K

    2014-12-01

    Radiation oncology has seen a rapid increase in the use of image-guided radiotherapy technology (IGRT) for prostate cancer patients over the past decade. The increase in the use of IGRT is largely driven by the fact that these technologies have been approved by the Food and Drug Administration and are now readily reimbursed by many insurance companies. Prostate cancer patients undergoing intensity modulated radiotherapy (IMRT) now have access to a wide variety of IGRTs that can cost anywhere from $500,000 or more in upfront costs, and can add anywhere from 10 to 15 thousand dollars to a course of IMRT. Some of the IGRT options include daily cone beam computed tomography, ultrasound, orthogonal x-ray units using implanted fiducial markers, implanted radiofrequency markers with the ability to localize and track prostate motion during radiotherapy (Calypso 4D), and cine magnetic resonance imaging. Although these technologies add to the cost of IMRT, there is little direct comparative effectiveness data to help patients, physicians, and policy makers decide if one technology is better than another. In our critical review, the first of its kind, we summarize the advantages, disadvantages, and the limitations of each technology. We also provide an overview of existing literature as it pertains to the comparison of existing IGRTs. Lastly, we provide insights about the need for future outcomes research that may have a significant impact on health policies as it comes to reimbursement in the modern era.

  5. Direct imaging of planetary systems with a ground-based radio telescope array

    NASA Technical Reports Server (NTRS)

    Jones, Dayton L.

    1994-01-01

    The National Radio Astronomy Observatory's proposed Millimeter Array (MMA) will bring unprecedented sensitivity, angular resolution, and image dynamic range to the millimeter wavelength region of the spectrum. An obvious question is whether such an instrument could be used to detect planets orbiting nearby stars. The techniques of aperture synthesis imaging developed for centimeter wavelength radio arrays are capable of producing images whose dynamic ranges greatly exceed the brightness ratio of a solar-type star and a Jupiter-like planet at sub-millimeter or millimeter wavelengths. The angular resolution required to separate a star and planet at a few pc distance can be obtained with baselines of several km. The greatest challenge is sensitivity. At the highest possible observing frequencies (approximately 300 GHz for typical high, dry sites, and approximately 900 GHz from the Antarctic plateau), the proposed MMA will be unable to detect the thermal emission from a Jupiter-like planet a few pc away. An upgraded MMA operating near 300 GHz with twice the currently proposed number of antennas, a 20% fractional bandwidth, and improved receivers could detect Jupiter at 4 pc in a few months. Building such an array on the Antarctic plateau and operating at approximately 900 GHz would allow Jupiter at 4 pc to be detected in approximately one day of observing time.

  6. Cosmic star formation probed via parametric stack-fitting of known sources to radio imaging

    NASA Astrophysics Data System (ADS)

    Roseboom, I. G.; Best, P. N.

    2014-04-01

    The promise of multiwavelength astronomy has been tempered by the large disparity in sensitivity and resolution between different wavelength regimes. Here, we present a statistical approach which attempts to overcome this by fitting parametric models directly to image data. Specifically, we fit a model for the radio luminosity function (LF) of star-forming galaxies to pixel intensity distributions at 1.4 GHz coincident with near-IR selected sources in COSMOS. Taking a mass-limited sample in redshift bins across the range 0 < z < 4, we are able to fit the radio LF with ˜0.2 dex precision in the key parameters (e.g. Φ*,L*). Good agreement is seen between our results and those using standard methods at radio and other wavelengths. Integrating our LFs to get the star formation rate density, we find that galaxies with M* > 109.5 M⊙ contribute ≳50 per cent of cosmic star formation at 0 < z < 4. The scalability of our approach is empirically estimated, with the precision in LF parameter estimates found to scale with the number of sources in the stack, Ns, as ∝ √{N_s}. This type of approach will be invaluable in the multiwavelength analysis of upcoming surveys with the Square Kilometre Array pathfinder facilities: LOFAR, ASKAP and MeerKAT.

  7. Multimodality Imaging of the Painful Elbow: Current Imaging Concepts and Image-Guided Treatments for the Injured Thrower's Elbow.

    PubMed

    Gustas, Cristy N; Lee, Kenneth S

    2016-09-01

    Elbow pain in overhead sport athletes is not uncommon. Repetitive throwing can lead to chronic overuse and/or acute injury to tendons, ligaments, bones, or nerves about the elbow. A thorough history and physical examination of the thrower's elbow frequently establishes the diagnosis for pain. Imaging can provide additional information when the clinical picture is unclear or further information is necessary for risk stratification and treatment planning. This article focuses on current imaging concepts and image-guided treatments for injuries commonly affecting the adult throwing athlete's elbow.

  8. Milliarcsecond Imaging of the Radio Emission from the Quasar with the Most Massive Black Hole at Reionization

    NASA Astrophysics Data System (ADS)

    Wang, Ran; Momjian, Emmanuel; Carilli, Chris L.; Wu, Xue-Bing; Fan, Xiaohui; Walter, Fabian; Strauss, Michael A.; Wang, Feige; Jiang, Linhua

    2017-02-01

    We report Very Long Baseline Array (VLBA) observations of the 1.5 GHz radio continuum emission of the z = 6.326 quasar SDSS J010013.02+280225.8 (hereafter J0100+2802). J0100+2802 is by far the most optically luminous and is a radio-quiet quasar with the most massive black hole known at z > 6. The VLBA observations have a synthesized beam size of 12.10 mas ×5.36 mas (FWHM), and detected the radio continuum emission from this object with a peak surface brightness of 64.6 ± 9.0 μJy beam‑1 and a total flux density of 88 ± 19 μJy. The position of the radio peak is consistent with that from SDSS in the optical and Chandra in the X-ray. The radio source is marginally resolved by the VLBA observations. A 2D Gaussian fit to the image constrains the source size to (7.1 ± 3.5) mas × (3.1 ± 1.7) mas. This corresponds to a physical scale of (40 ± 20) pc × (18 ± 10) pc. We estimate the intrinsic brightness temperature of the VLBA source to be TB = (1.6 ± 1.2) × 107 K. This is significantly higher than the maximum value in normal star-forming galaxies, indicating an active galactic nucleus (AGN) origin for the radio continuum emission. However, it is also significantly lower than the brightness temperatures found in highest-redshift radio-loud quasars. J0100+2802 provides a unique example for studying the radio activity in optically luminous and radio-quiet AGNs in the early universe. Further observations at multiple radio frequencies will accurately measure the spectral index and address the dominant radiation mechanism of the radio emission.

  9. Ultrasound stylet for non-image-guided ventricular catheterization.

    PubMed

    Coulson, Nathaniel K; Chiarelli, Peter A; Su, David K; Chang, Jason J; MacConaghy, Brian; Murthy, Revathi; Toms, Peter; Robb, Terrence L; Ellenbogen, Richard G; Browd, Samuel R; Mourad, Pierre D

    2015-10-01

    OBJECT Urgent ventriculostomy placement can be a lifesaving procedure in the setting of hydrocephalus or elevated intracranial pressure. While external ventricular drain (EVD) insertion is common, there remains a high rate of suboptimal drain placement. Here, the authors seek to demonstrate the feasibility of an ultrasound-based guidance system that can be inserted into an existing EVD catheter to provide a linear ultrasound trace that guides the user toward the ventricle. METHODS The ultrasound stylet was constructed as a thin metal tube, with dimensions equivalent to standard catheter stylets, bearing a single-element, ceramic ultrasound transducer at the tip. Ultrasound backscatter signals from the porcine ventricle were processed by custom electronics to offer real-time information about ventricular location relative to the catheter. Data collected from the prototype device were compared with reference measurements obtained using standard clinical ultrasound imaging. RESULTS A study of porcine ventricular catheterization using the experimental device yielded a high rate of successful catheter placement after a single pass (10 of 12 trials), despite the small size of pig ventricles and the lack of prior instruction on porcine ventricular architecture. A characteristic double-peak signal was identified, which originated from ultrasound reflections off of the near and far ventricular walls. Ventricular dimensions, as obtained from the width between peaks, were in agreement with standard ultrasound reference measurements (p < 0.05). Furthermore, linear ultrasound backscatter data permitted in situ measurement of the stylet distance to the ventricular wall (p < 0.05), which assisted in catheter guidance. CONCLUSIONS The authors have demonstrated the ability of the prototype ultrasound stylet to guide ventricular access in the porcine brain. The alternative design of the device makes it potentially easy to integrate into the standard workflow for bedside EVD

  10. Sparsity based defect imaging in pipes using guided waves

    NASA Astrophysics Data System (ADS)

    Golato, Andrew; Santhanam, Sridhar; Ahmad, Fauzia; Amin, Moeness G.

    2016-05-01

    Pipes are used for the transport of fluids and gases in urban and industrial settings, such as buried pipelines to transport water, oil, and other resources. To ensure reliable operation, it is essential that an inspection system be in place to identify and localize damage/defects in the pipes. Unfortunately, many of the typical nondestructive evaluation techniques are inadequate due to limited pipe access; often, only the beginning and end sections of the pipe are physically accessible. As such, this problem is well suited to the use of ultrasonic guided-wave based structural health monitoring. With a limited number of transducers, ultrasonic guided waves can be used to interrogate long lengths of pipes. In this paper, we propose a damage detection and localization scheme that relies upon the inherent sparsity of defects in the pipes. A sparse array of transducers, deployed in accessible areas of the pipes, is utilized in pitch-catch mode to record signals scattered by defects in the pipe. Both the direct path scattering off the defect, and the helical modes, which are paths that spiral around the circumference of the pipe before or after interaction with the defect, are recorded. A Lamb wave based signal model is formulated that accounts for this multipath approach. The signal model is then inverted via group sparse reconstruction, in order to produce an image of the scene. The model accounts for the specificities of Lamb wave propagation through the pipe. Performance validation of the proposed approach is provided using simulated data for an aluminum pipe.

  11. The Radio JOVE Project

    NASA Astrophysics Data System (ADS)

    Garcia, L.; Thieman, J.; Higgins, C.

    1999-09-01

    Radio JOVE is an interactive educational activity which brings the radio sounds of Jupiter and the Sun to students, teachers, and the general public. This is accomplished through the construction of a simple radio telescope kit and the use of a real-time radio observatory on the Internet. Our website (http://radiojove.gsfc.nasa.gov/) will contain science information, instruction manuals, observing guides, and education resources for students and teachers. Our target audience is high school science classes, but subjects can be tailored to college undergraduate physics and astronomy courses or even to middle school science classes. The goals of the project are: 1) Educate people about planetary and solar radio astronomy, space physics, and the scientific method 2) Provide teachers and students with a hands-on radio astronomy exercise as a science curriculum support activity by building and using a simple radio telescope receiver/antenna kit 3) Create the first ever online radio observatory which provides real-time data for those with internet access 4) Allow interactions among participating schools by facilitating exchanges of ideas, data, and observing experiences. Our current funding will allow us to impact 100 schools by partially subsidizing their participation in the program. We expect to expand well beyond this number as publicity and general interest increase. Additional schools are welcome to fully participate, but we will not be able to subsidize their kit purchases. We hope to make a wide impact among the schools by advertising through appropriate newsletters, space grant consortia, the INSPIRE project (http://image.gsfc.nasa.gov/poetry/inspire/), electronic links, and science and education meetings. We would like to acknoledge support from the NASA/GSFC Director's Discretionary Fund, the STScI IDEAS grant program and the NASA/GSFC Space Science Data Operations Office.

  12. Fluorescence lifetime imaging microscopy for brain tumor image-guided surgery

    NASA Astrophysics Data System (ADS)

    Sun, Yinghua; Hatami, Nisa; Yee, Matthew; Phipps, Jennifer; Elson, Daniel S.; Gorin, Fredric; Schrot, Rudolph J.; Marcu, Laura

    2010-09-01

    We demonstrate for the first time the application of an endoscopic fluorescence lifetime imaging microscopy (FLIM) system to the intraoperative diagnosis of glioblastoma multiforme (GBM). The clinically compatible FLIM prototype integrates a gated (down to 0.2 ns) intensifier imaging system with a fiber-bundle (fiber image guide of 0.5 mm diameter, 10,000 fibers with a gradient index lens objective 0.5 NA, and 4 mm field of view) to provide intraoperative access to the surgical field. Experiments conducted in three patients undergoing craniotomy for tumor resection demonstrate that FLIM-derived parameters allow for delineation of tumor from normal cortex. For example, at 460+/-25-nm wavelength band emission corresponding to NADH/NADPH fluorescence, GBM exhibited a weaker florescence intensity (35% less, p-value <0.05) and a longer lifetime τGBM-Amean=1.59+/-0.24 ns than normal cortex τNC-Amean=1.28+/-0.04 ns (p-value <0.005). Current results demonstrate the potential use of FLIM as a tool for image-guided surgery of brain tumors.

  13. Recent Results From the Whistler- and Z-mode Radio Sounding From the IMAGE Satellite

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V. S.; Reddy, A.; Mayank, K.; Hazra, S.; Carpenter, D. L.

    2014-12-01

    Whistler mode radio sounding method [Sonwalkar et al., JGR, 2011] was applied to two case studies: (1) daytime and nighttime cases of whistler mode echoes observed on IMAGE inside the plasmasphere (L<4, altitude <5000 km), and (2) cases of whistler mode echoes observed during geomagnetic storm activity. Preliminary results indicate: (i) O+/H+ and O+/ (H+ + He+) transition heights at nighttime are a few hundred kilometers lower than that at daytime. (ii) Electron and ion densities found from whistler mode sounding are consistent with those from the past in situ and radio sounding measurements, but differ from those predicted by IRI-2012 and GCPM. (iii) Electron and ion densities undergo temporal changes as a function of geomagnetic storm activity, and each species has different recovery period. (iv) Major, moderate, and minor storms affect Ne, H+, and O+ densities in a similar manner, but affect He+ density differently-the minor storm did not affect it. By comparing the electron and ion densities measured by whistler mode radio sounding with those predicted by physics based ionospheric models (e.g. SAMI 2) it may be possible to understand how thermospheric winds influence the evolution of the ionospheric electron and ion densities during geomagnetic storms. The application of Sonwalkar et al. [2011] method to nonducted and ducted fast Z mode echoes observed on IMAGE has led to the measurement of field aligned electron density and duct width and enhancement factor from ~1000 km up to the equator. In two cases, ducts with widths of ~0.05-0.1 L and density depletions of ~5-10 % accounted for the observed properties of ducted Z mode echoes. The measurements of both electron density and ducts are consistent with past measurements. The results from the whistler and Z mode sounding will lead to new empirical models of field aligned electron and ion densities and a statistical characterization of ducts in the magnetosphere.

  14. Image improvement from a sodium-layer laser guide star adaptive optics system

    SciTech Connect

    Max, C. E., LLNL

    1997-06-01

    A sodium-layer laser guide star beacon with high-order adaptive optics at Lick Observatory produced a factor of 2.4 intensity increase and a factor of 2 decrease in full width at half maximum for an astronomical point source, compared with image motion compensation alone. Image full widths at half maximum were identical for laser and natural guide stars (0.3 arc seconds). The Strehl ratio with the laser guide star was 65% of that with a natural guide star. This technique should allow ground-based telescopes to attain the diffraction limit, by correcting for atmospheric distortions.

  15. [Treatment of a solitary adenoma of the parathyroid gland with ultrasound-guided percutaneous Radio-Frequency-Tissue-Ablation (RFTA)].

    PubMed

    Hänsler, J; Harsch, I A; Strobel, D; Hahn, E G; Becker, D

    2002-06-01

    Radio-Frequency-Tissue-Ablation (RFTA) for the treatment of primary and secondary tumours of the liver has been used for several years, but this minimally invasive treatment is not limited to the liver. A patient suffering from symptomatic postmenopausal osteoporosis, additionally having primary hyperparathyroidism since 1995, refused a surgical resection of the adenoma of the parathyroid gland. Sonographically a 16 mm hypoechoic tumour dorsal of the right upper pole of the thyroid gland was detected. Osteodensitometry: severe osteoporosis of the lumbar spine (88 % of the norm for this age group). Blood check: Elevation of serum calcium level (3.1mmol/l) and serum parathormone level 274 pg/dl (N: 10-50). A percutaneous ultrasound guided RFTA of the adenoma of the thyroid gland was carried out. After RFTA the serum parathormone levels and the serum calcium levels dropped back to normal. The patient was followed-up for one year. For the first time a sufficient therapy for osteoporosis comprising calcium, etidronate and cholecalciferol could be carried out. The osteodensitometry carried out one year after treatment showed an increase in bone density. For the treatment of symptomatic primary hyperparathyroidism RFTA can be a therapeutic alternative for patients with contraindications for surgery.

  16. Technician-free system for image-guided bronchoscopy

    NASA Astrophysics Data System (ADS)

    Khare, Rahul; Bascom, Rebecca; Higgins, William E.

    2013-03-01

    Previous studies have shown that guidance systems improve accuracy and reduce skill variation among physicians during bronchoscopy. However, most of these systems suffer from one or more of the following limitations: 1) an attending technician must carefully keep the system position synchronized with the bronchoscope position during the procedure; 2) extra bronchoscope tracking hardware may be required; 3) guidance cannot take place in real time; 4) the guidance system is unable to detect and correct faulty bronchoscope maneuvers; and 5) a resynchronization procedure must be followed after adverse events such as patient cough or dynamic airway collapse. Here, we propose an image-based system for technician-free bronchoscopy guidance that relies on two features. First, our system precomputes a guidance plan that suggests natural bronchoscope maneuvers at every bifurcation leading toward a region of interest (ROI). Second, our system enables bronchoscope position verification that relies on a global-registration algorithm to establish the global bronchoscope position and, thus, provide the physician with updated navigational information during bronchoscopy. The system can handle general navigation to an ROI, as well as adverse events, and is directly controlled by the physician by a foot pedal. Guided bronchoscopy results using airway-tree phantoms and human cases demonstrate the efficacy of the system.

  17. Cyberknife Image-Guided Delivery and Quality Assurance

    SciTech Connect

    Dieterich, Sonja; Pawlicki, Todd

    2008-05-01

    The CyberKnife is a complex, emerging technology that is a significant departure from current stereotactic radiosurgery and external beam radiotherapy technologies. In its clinical application and quality assurance (QA) approach, the CyberKnife is currently situated somewhere in between stereotactic radiosurgery and radiotherapy. The clinical QA for this image-guided treatment delivery system typically follows the vendor's guidance, mainly because of the current lack of vendor-independent QA recommendations. The problem has been exacerbated because very little published data are available for QA for the CyberKnife system, especially for QA of the interaction between individual system components. The tools and techniques for QA of the CyberKnife are under development and will continue to improve with longer clinical experience of the users. The technology itself continues to evolve, forcing continuous changes and adaptation of QA. To aid in the process of developing comprehensive guidance on CyberKnife QA, a database of errors based on users reporting incidents and corrective actions would be desirable. The goal of this work was to discuss the status of QA guidelines in the clinical implementation of the CyberKnife system. This investigation was done from the perspective of an active clinical and research site using the CyberKnife.

  18. Ultrasound in Radiology: from Anatomic, Functional, Molecular Imaging to Drug Delivery and Image-Guided Therapy

    PubMed Central

    Klibanov, Alexander L.; Hossack, John A.

    2015-01-01

    During the past decade, ultrasound has expanded medical imaging well beyond the “traditional” radiology setting - a combination of portability, low cost and ease of use makes ultrasound imaging an indispensable tool for radiologists as well as for other medical professionals who need to obtain imaging diagnosis or guide a therapeutic intervention quickly and efficiently. Ultrasound combines excellent ability for deep penetration into soft tissues with very good spatial resolution, with only a few exceptions (i.e. those involving overlying bone or gas). Real-time imaging (up to hundreds and thousands frames per second) enables guidance of therapeutic procedures and biopsies; characterization of the mechanical properties of the tissues greatly aids with the accuracy of the procedures. The ability of ultrasound to deposit energy locally brings about the potential for localized intervention encompassing: tissue ablation, enhancing penetration through the natural barriers to drug delivery in the body and triggering drug release from carrier micro- and nanoparticles. The use of microbubble contrast agents brings the ability to monitor and quantify tissue perfusion, and microbubble targeting with ligand-decorated microbubbles brings the ability to obtain molecular biomarker information, i.e., ultrasound molecular imaging. Overall, ultrasound has become the most widely used imaging modality in modern medicine; it will continue to grow and expand. PMID:26200224

  19. Efficacy of sclerotherapy with radio-opaque foam guided by digital subtraction angiography for the treatment of complex venous malformations of the head and neck.

    PubMed

    Chen, A-W; Liu, Y-R; Li, K; Zhang, K; Wang, T; Liu, S-H

    2015-11-01

    Our aim was to evaluate the efficacy of sclerotherapy using radio-opaque foam and guided by digital subtraction angiography (DSA) for complex venous malformations in the head and neck in 11 selected patients between 2011 and 2013. The sclerosing foam was manufactured by the classic Tessari method and consisted of air, 1% polidocanol, and radio-opaque media iopromide (Ultravist(®)300) in a ratio of 7:2:1. We recorded the site and size of the lesion, time and duration of treatment, and therapeutic response. The lesions were on the face, cheek, temporal region, parotid region, neck, tongue, floor of the mouth, parapharyngeal space, and soft palate. The sclerosing foam was radio-opaque under DSA, and the mean (range) dose was 21 (3-65) ml. A mean (range) of 4 (2-7) treatments was required, and 10 of the 11 patients responded well. In 4 of the 11 cases the lesion resolved completely and in 6 there was a good response. Only one lesion recurred. Early complications included immediate swelling in injected areas, snoring, and pain on swallowing, but there were no air emboli or signs of cutaneous necrosis, and the complications were self-limiting. DSA-guided sclerotherapy with radio-opaque foam was safe and effective for the treatment of complex vascular malformations of the head and neck.

  20. Multi-Frequency Synthesis - a New Technique in Radio Interferometric Imaging

    NASA Astrophysics Data System (ADS)

    Conway, J. E.; Cornwell, T. J.; Wilkinson, P. N.

    1990-10-01

    We describe an extension to aperture synthesis, multi-frequency synthesis or MFS, whose principal goal is to allow high-quality radio images to be obtained from spars interferometric arrays. The idea is to use data from a relatively narrow range of frequencies (typically +/- 10 per cent) to produce a major improvement in the aperture-plane coverage of an array. From these data one can reconstruct an image at a single reference frequency in which the 'reconstruction errors', which normally occur as a result of large 'holes' in the aperture plane, are much reduced. The obvious problem to -be overcome is that the source brightness distribution is slightly different at each frequency. We analyse the 'spectral errors' introduced into the reconstructed image by this frequency-dependent structure. For a +/- 1 2.5 per cent range of frequencies we show that typically, spectral errors will be below the thermal noise level provided that the ratio of the peak brightness (excluding any compact component such as a radio core) to rms noise is less than a thousand-to-one, Unresolved features can be identified easily and effectively removed from the data a each frequency and hence they need not be a source of spectral errors. When this spectral errors are above the noise they can be recognized and removed by an extension to the well-established CLEAN deconvolution methodi We call the new method 'double deconvolution', or DD, and demonstrate its effectiveness 0 simulated data. The primary motivation beyond narrow-band MFS observations is to produce improved intensity images, rather than to determine spectral index distributions. Although the DD algorithm effectively estimates the spectral index distribution in the course of removing spectral effects, these estimates will be crude and not generally of astrophysical use. We briefly consider the practical problems involved in making MFS observations and conclude that the major limiting factor is likely to be radio

  1. Quantification and comparison of visibility and image artifacts of a new liquid fiducial marker in a lung phantom for image-guided radiation therapy

    SciTech Connect

    Scherman Rydhög, Jonas Munck af Rosenschöld, Per; Irming Jølck, Rasmus; Andresen, Thomas Lars

    2015-06-15

    Purpose: A new biodegradable liquid fiducial marker was devised to allow for easy insertion in lung tumors using thin needles. The purpose of this study was to evaluate the visibility of the liquid fiducial markers for image-guided radiation therapy and compare to existing solid fiducial markers and to one existing liquid fiducial marker currently commercially available. Methods: Fiducial marker visibility was quantified in terms of contrast to noise ratio (CNR) on planar kilovoltage x-ray images in a thorax phantom for different concentrations of the radio-opaque component of the new liquid fiducial marker, four solid fiducial markers, and one existing liquid fiducial marker. Additionally, the image artifacts produced on computer tomography (CT) and cone-beam CT (CBCT) of all fiducial markers were quantified. Results: The authors found that the new liquid fiducial marker with the highest concentration of the radio-opaque component had a CNR > 2.05 for 62/63 exposures, which compared favorably to the existing solid fiducial markers and to the existing liquid fiducial marker evaluated. On CT and CBCT, the new liquid fiducial marker with the highest concentration produced lower streaking index artifact (30 and 14, respectively) than the solid gold markers (113 and 20, respectively) and the existing liquid fiducial marker (39 and 20, respectively). The size of the image artifact was larger for all of the liquid fiducial markers compared to the solid fiducial markers because of their larger physical size. Conclusions: The visibility and the image artifacts produced by the new liquid fiducial markers were comparable to existing solid fiducial markers and the existing liquid fiducial marker. The authors conclude that the new liquid fiducial marker represents an alternative to the fiducial markers tested.

  2. Versatility of the Novalis system to deliver image-guided stereotactic body radiation therapy (SBRT) for various anatomical sites.

    PubMed

    Teh, Bin S; Paulino, Arnold C; Lu, Hsin H; Chiu, J Kam; Richardson, Susan; Chiang, Stephen; Amato, Robert; Butler, E Brian; Bloch, Charles

    2007-08-01

    Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) programs to treat brain tumors were implemented when we first acquired the Brainlab Novalis system in 2003. Two years later, we started an extra-cranial stereotactic radio-ablation or more appropriately a stereotactic body radiation therapy (SBRT) program using the Brainlab Novalis image-guided system at The Methodist Hospital in Houston, Texas. We hereby summarize our initial experience with this system in delivering image-guided SBRT to a total of 80 patients during our first year of clinical implementation, from February 2005 to January 2006. Over 100 lesions in more than 20 distinct anatomical sites were treated. These include all levels of spine from cervical, thoracic, lumbar, and sacral lesions. Spinal lesions encompass intramedullary, intradural, extradural, or osseous compartments. Also treated were lesions in other bony sites including orbit, clavicle, scapula, humerus, sternum, rib, femur, and pelvis (ilium, ischium, and pubis). Primary or metastatic lesions located in the head and neck, supraclavicular region, axilla, mediastinum, lung (both central and peripheral), abdominal wall, liver, kidney, para-aortic lymph nodes, prostate, and pelvis were also treated. In addition to primary radiotherapy, SBRT program using the Brainlab Novalis system allows re-irradiation for recurrence and "boost" after conventional treatment to various anatomical sites. Treating these sites safely and efficaciously requires knowledge in radiation tolerance, fraction size, total dose, biologically equivalent dose (BED), prior radiotherapy, detailed dose volume histograms (DVH) of normal tissues, and the radiosensitive/radioresistant nature of the tumor. Placement of radio-opaque markers (Visicoil, Radiomed) in anatomical sites not in close proximity to bony landmarks (e.g., kidney and liver) helps in measuring motion and providing image guidance during each treatment fraction. Tumor/organ motion

  3. Spatially weighted mutual information image registration for image guided radiation therapy

    SciTech Connect

    Park, Samuel B.; Rhee, Frank C.; Monroe, James I.; Sohn, Jason W.

    2010-09-15

    Purpose: To develop a new metric for image registration that incorporates the (sub)pixelwise differential importance along spatial location and to demonstrate its application for image guided radiation therapy (IGRT). Methods: It is well known that rigid-body image registration with mutual information is dependent on the size and location of the image subset on which the alignment analysis is based [the designated region of interest (ROI)]. Therefore, careful review and manual adjustments of the resulting registration are frequently necessary. Although there were some investigations of weighted mutual information (WMI), these efforts could not apply the differential importance to a particular spatial location since WMI only applies the weight to the joint histogram space. The authors developed the spatially weighted mutual information (SWMI) metric by incorporating an adaptable weight function with spatial localization into mutual information. SWMI enables the user to apply the selected transform to medically ''important'' areas such as tumors and critical structures, so SWMI is neither dominated by, nor neglects the neighboring structures. Since SWMI can be utilized with any weight function form, the authors presented two examples of weight functions for IGRT application: A Gaussian-shaped weight function (GW) applied to a user-defined location and a structures-of-interest (SOI) based weight function. An image registration example using a synthesized 2D image is presented to illustrate the efficacy of SWMI. The convergence and feasibility of the registration method as applied to clinical imaging is illustrated by fusing a prostate treatment planning CT with a clinical cone beam CT (CBCT) image set acquired for patient alignment. Forty-one trials are run to test the speed of convergence. The authors also applied SWMI registration using two types of weight functions to two head and neck cases and a prostate case with clinically acquired CBCT/MVCT image sets. The

  4. An integrated platform for image-guided cardiac resynchronization therapy

    NASA Astrophysics Data System (ADS)

    Ma, Ying Liang; Shetty, Anoop K.; Duckett, Simon; Etyngier, Patrick; Gijsbers, Geert; Bullens, Roland; Schaeffter, Tobias; Razavi, Reza; Rinaldi, Christopher A.; Rhode, Kawal S.

    2012-05-01

    Cardiac resynchronization therapy (CRT) is an effective procedure for patients with heart failure but 30% of patients do not respond. This may be due to sub-optimal placement of the left ventricular (LV) lead. It is hypothesized that the use of cardiac anatomy, myocardial scar distribution and dyssynchrony information, derived from cardiac magnetic resonance imaging (MRI), may improve outcome by guiding the physician for optimal LV lead positioning. Whole heart MR data can be processed to yield detailed anatomical models including the coronary veins. Cine MR data can be used to measure the motion of the LV to determine which regions are late-activating. Finally, delayed Gadolinium enhancement imaging can be used to detect regions of scarring. This paper presents a complete platform for the guidance of CRT using pre-procedural MR data combined with live x-ray fluoroscopy. The platform was used for 21 patients undergoing CRT in a standard catheterization laboratory. The patients underwent cardiac MRI prior to their procedure. For each patient, a MRI-derived cardiac model, showing the LV lead targets, was registered to x-ray fluoroscopy using multiple views of a catheter looped in the right atrium. Registration was maintained throughout the procedure by a combination of C-arm/x-ray table tracking and respiratory motion compensation. Validation of the registration between the three-dimensional (3D) roadmap and the 2D x-ray images was performed using balloon occlusion coronary venograms. A 2D registration error of 1.2 ± 0.7 mm was achieved. In addition, a novel navigation technique was developed, called Cardiac Unfold, where an entire cardiac chamber is unfolded from 3D to 2D along with all relevant anatomical and functional information and coupled to real-time device detection. This allowed more intuitive navigation as the entire 3D scene was displayed simultaneously on a 2D plot. The accuracy of the unfold navigation was assessed off-line using 13 patient data sets

  5. MIND Demons for MR-to-CT Deformable Image Registration In Image-Guided Spine Surgery

    PubMed Central

    Reaungamornrat, S.; De Silva, T.; Uneri, A.; Wolinsky, J.-P.; Khanna, A. J.; Kleinszig, G.; Vogt, S.; Prince, J. L.; Siewerdsen, J. H.

    2016-01-01

    Purpose Localization of target anatomy and critical structures defined in preoperative MR images can be achieved by means of multi-modality deformable registration to intraoperative CT. We propose a symmetric diffeomorphic deformable registration algorithm incorporating a modality independent neighborhood descriptor (MIND) and a robust Huber metric for MR-to-CT registration. Method The method, called MIND Demons, solves for the deformation field between two images by optimizing an energy functional that incorporates both the forward and inverse deformations, smoothness on the velocity fields and the diffeomorphisms, a modality-insensitive similarity function suitable to multi-modality images, and constraints on geodesics in Lagrangian coordinates. Direct optimization (without relying on an exponential map of stationary velocity fields used in conventional diffeomorphic Demons) is carried out using a Gauss-Newton method for fast convergence. Registration performance and sensitivity to registration parameters were analyzed in simulation, in phantom experiments, and clinical studies emulating application in image-guided spine surgery, and results were compared to conventional mutual information (MI) free-form deformation (FFD), local MI (LMI) FFD, and normalized MI (NMI) Demons. Result The method yielded sub-voxel invertibility (0.006 mm) and nonsingular spatial Jacobians with capability to preserve local orientation and topology. It demonstrated improved registration accuracy in comparison to the reference methods, with mean target registration error (TRE) of 1.5 mm compared to 10.9, 2.3, and 4.6 mm for MI FFD, LMI FFD, and NMI Demons methods, respectively. Validation in clinical studies demonstrated realistic deformation with sub-voxel TRE in cases of cervical, thoracic, and lumbar spine. Conclusions A modality-independent deformable registration method has been developed to estimate a viscoelastic diffeomorphic map between preoperative MR and intraoperative CT. The

  6. MIND Demons for MR-to-CT deformable image registration in image-guided spine surgery

    NASA Astrophysics Data System (ADS)

    Reaungamornrat, S.; De Silva, T.; Uneri, A.; Wolinsky, J.-P.; Khanna, A. J.; Kleinszig, G.; Vogt, S.; Prince, J. L.; Siewerdsen, J. H.

    2016-03-01

    Purpose: Localization of target anatomy and critical structures defined in preoperative MR images can be achieved by means of multi-modality deformable registration to intraoperative CT. We propose a symmetric diffeomorphic deformable registration algorithm incorporating a modality independent neighborhood descriptor (MIND) and a robust Huber metric for MR-to-CT registration. Method: The method, called MIND Demons, solves for the deformation field between two images by optimizing an energy functional that incorporates both the forward and inverse deformations, smoothness on the velocity fields and the diffeomorphisms, a modality-insensitive similarity function suitable to multi-modality images, and constraints on geodesics in Lagrangian coordinates. Direct optimization (without relying on an exponential map of stationary velocity fields used in conventional diffeomorphic Demons) is carried out using a Gauss-Newton method for fast convergence. Registration performance and sensitivity to registration parameters were analyzed in simulation, in phantom experiments, and clinical studies emulating application in image-guided spine surgery, and results were compared to conventional mutual information (MI) free-form deformation (FFD), local MI (LMI) FFD, and normalized MI (NMI) Demons. Result: The method yielded sub-voxel invertibility (0.006 mm) and nonsingular spatial Jacobians with capability to preserve local orientation and topology. It demonstrated improved registration accuracy in comparison to the reference methods, with mean target registration error (TRE) of 1.5 mm compared to 10.9, 2.3, and 4.6 mm for MI FFD, LMI FFD, and NMI Demons methods, respectively. Validation in clinical studies demonstrated realistic deformation with sub-voxel TRE in cases of cervical, thoracic, and lumbar spine. Conclusions: A modality-independent deformable registration method has been developed to estimate a

  7. Hierarchical content-based image retrieval by dynamic indexing and guided search

    NASA Astrophysics Data System (ADS)

    You, Jane; Cheung, King H.; Liu, James; Guo, Linong

    2003-12-01

    This paper presents a new approach to content-based image retrieval by using dynamic indexing and guided search in a hierarchical structure, and extending data mining and data warehousing techniques. The proposed algorithms include: a wavelet-based scheme for multiple image feature extraction, the extension of a conventional data warehouse and an image database to an image data warehouse for dynamic image indexing, an image data schema for hierarchical image representation and dynamic image indexing, a statistically based feature selection scheme to achieve flexible similarity measures, and a feature component code to facilitate query processing and guide the search for the best matching. A series of case studies are reported, which include a wavelet-based image color hierarchy, classification of satellite images, tropical cyclone pattern recognition, and personal identification using multi-level palmprint and face features.

  8. DERIVATION OF THE MAGNETIC FIELD IN A CORONAL MASS EJECTION CORE VIA MULTI-FREQUENCY RADIO IMAGING

    SciTech Connect

    Tun, Samuel D.; Vourlidas, A.

    2013-04-01

    The magnetic field within the core of a coronal mass ejection (CME) on 2010 August 14 is derived from analysis of multi-wavelength radio imaging data. This CME's core was found to be the source of a moving type IV radio burst, whose emission is here determined to arise from the gyrosynchrotron process. The CME core's true trajectory, electron density, and line-of-sight depth are derived from stereoscopic observations, constraining these parameters in the radio emission models. We find that the CME carries a substantial amount of mildly relativistic electrons (E < 100 keV) in a strong magnetic field (B < 15 G), and that the spectra at lower heights are preferentially suppressed at lower frequencies through absorption from thermal electrons. We discuss the results in light of previous moving type IV burst studies, and outline a plan for the eventual use of radio methods for CME magnetic field diagnostics.

  9. RADIO IMAGING OBSERVATIONS OF PSR J1023+0038 IN AN LMXB STATE

    SciTech Connect

    Deller, A. T.; Moldon, J.; Patruno, A.; Hessels, J. W. T.; Archibald, A. M.; Heald, G.; Vilchez, N.; Miller-Jones, J. C. A.; Paragi, Z.

    2015-08-10

    The transitional millisecond pulsar (MSP) binary system PSR J1023+0038 re-entered an accreting state in 2013 June in which it bears many similarities to low-mass X-ray binaries (LMXBs) in quiescence or near-quiescence. At a distance of just 1.37 kpc, PSR J1023+0038 offers an unsurpassed ability to study low-level accretion onto a highly magnetized compact object. We have monitored PSR J1023+0038 intensively using radio imaging with the Karl G. Jansky Very Large Array, the European VLBI Network and the Low Frequency Array, seeing rapidly variable, flat spectrum emission that persists over a period of six months. The flat spectrum and variability are indicative of synchrotron emission originating in an outflow from the system, most likely in the form of a compact, partially self-absorbed jet, as is seen in LMXBs at higher accretion rates. The radio brightness, however, greatly exceeds extrapolations made from observations of more vigorously accreting neutron star LMXB systems. We postulate that PSR J1023+0038 is undergoing radiatively inefficient “propeller-mode” accretion, with the jet carrying away a dominant fraction of the liberated accretion luminosity. We confirm that the enhanced γ-ray emission seen in PSR J1023+0038 since it re-entered an accreting state has been maintained; the increased γ-ray emission in this state can also potentially be associated with propeller-mode accretion. Similar accretion modes can be invoked to explain the radio and X-ray properties of the other two known transitional MSP systems XSS J12270–4859 and PSR J1824–2452I (M28I), suggesting that radiatively inefficient accretion may be a ubiquitous phenomenon among (at least one class of) neutron star binaries at low accretion rates.

  10. Radio-adaptive Response in Myocardial Perfusion Imaging Induced by Technetium-99m

    PubMed Central

    Shirazi, Mohammad Mehdi; Shabestani-Monfared, Ali; Shahidi, Maryam; Amiri, Mehrangiz; Abedi, Seyed Mohammad; Borzoueisileh, Sajad; Gorji, Kourosh Ebrahim Nejad

    2017-01-01

    Purpose of the Study: Low dose radiation will induce adaptation and following exposure to an adaptive dose, the cells are more resistance to following challenging doses. This phenomenon is known as radio-adaptive response. The aim of this study was to investigate the percentage of apoptotic cells in the peripheral blood samples of the patients which undergo myocardial perfusion imaging (MPI) with technetium-99m (Tc-99m) before thallium scan to assess the induction of radio-adaptive response. Materials and Methods: In this study, 97 samples from 74 patients, referred to nuclear medicine center of Mazandaran Heart Hospital for MPI, which had no history of diagnostic, therapeutic, occupational, and radioactive exposures during past 2 years, were provided. The participants were classified into four groups including control, patients which were scanned solely with technetium, the patients which examined by thallium and the last group were the patients that examined by technetium followed by thallium. Then 2 ml Peripheral blood samples were obtained, and after 24 h incubating, the samples were studied by neutral comet assay. Statistical analysis was carried out using Student's t-test along with one-way analysis of variance. Results: The mean percentage of apoptotic cells in the exposed groups were higher than the control. Furthermore, among exposed groups, the apoptotic cells in thallium group were more than others and this index was significantly lower in the group which was undergone technetium administration before thallium scan. Conclusions: These findings suggest that exposure to Tc-99m could induce a radio-adaptive response against the exposure of thallium-201. PMID:28242975

  11. Performance of a small CdTe gamma camera for radio-guided surgery

    NASA Astrophysics Data System (ADS)

    Tsuchimochi, Makoto; Sakahara, Harmui; Hayama, Kazuhide; Funaki, Minoru; Shirahata, T.; Orskaug, Terje; Maehlum, Gunnar; Yoshioka, Koki; Nygard, Einar

    2001-12-01

    Sentinel lymph node biopsy has been shown to be highly accurate for detecting metastatic diseases, such as melanoma and breast cancer. Gamma probes that measure only the relative presence of radioactivity are commonly used to identify sentinel lymph nodes. We have developed a small semiconductor gamma camera (SSGC) that allows the size, shape, and location of the target tissues to be visualized. The purpose of this study is to characterize the performance of the SSGC for radioguided surgery of metastatic lesions and for diagnosing other diseases amenable to the smaller- format associated with this prototype imaging system. Methods & Design: The detector head was comprised of a 32 x 32 Cadmium Telluride semiconductor array and application- specific integrated circuit (ASIC) with a tungsten collimator. The entire assembly was encased in a lead housing measuring 152 mm x 166 mm x 65 mm. The effective visual field was 44.8 mm x 44.8 mm. Two spherical 5 mm diameter Tc-99m radioactive sources having activities of 0.15 MBq and 100 MBq were used to simulate sentinel lymph nodes and injection site. The relative detectability of these foci was compared using the new detector and a conventional scintillation camera. Use of the prototype was also explored on patients in a variety of clinical applications. Results: the SSGC provided better spatial resolution on phantom studies than the conventional gamma camera control. Both foci could be visualized clearly by the SSGC using a 15 second acquisition time, whereas they could not be readily identified using the conventional system under comparable conditions. Preliminary clinical tests of the SSGC were found to be successful in imaging diseases in a variety of tissues including salivary and thyroid glands, temporomandibular joints, and sentinel lymph nodes. Conclusion: The SSGC has significant potential for use in diagnosing diseases and for facilitating subsequent radioguided surgery. (This project was supported by a Grant- in

  12. Rician noise reduction in magnetic resonance images using adaptive non-local mean and guided image filtering

    NASA Astrophysics Data System (ADS)

    Mahmood, Muhammad Tariq; Chu, Yeon-Ho; Choi, Young-Kyu

    2016-06-01

    This paper proposes a Rician noise reduction method for magnetic resonance (MR) images. The proposed method is based on adaptive non-local mean and guided image filtering techniques. In the first phase, a guidance image is obtained from the noisy image through an adaptive non-local mean filter. Sobel operators are applied to compute the strength of edges which is further used to control the spread of the kernel in non-local mean filtering. In the second phase, the noisy and the guidance images are provided to the guided image filter as input to restore the noise-free image. The improved performance of the proposed method is investigated using the simulated and real data sets of MR images. Its performance is also compared with the previously proposed state-of-the art methods. Comparative analysis demonstrates the superiority of the proposed scheme over the existing approaches.

  13. Use of image guided radiation therapy techniques and imaging dose measurement at Indian hospitals: A survey

    PubMed Central

    Deshpande, Sudesh; Dhote, D. S.; Kumar, Rajesh; Naidu, Suresh; Sutar, A.; Kannan, V.

    2015-01-01

    A national survey was conducted to obtain information about the use of image-guided radiotherapy (IGRT) techniques and IGRT dose measurement methods being followed at Indian radiotherapy centers. A questionnaire containing parameters relevant to use of IGRT was prepared to collect the information pertaining to (i) availability and type of IGRT delivery system, (ii) frequency of image acquisition protocol and utilization of these images for different purpose, and (iii) imaging dose measurement. The questionnaire was circulated to 75 hospitals in the country having IGRT facility, and responses of 51 centers were received. Survey results showed that among surveyed hospitals, 86% centers have IGRT facility, 78% centers have kilo voltage three-dimensional volumetric imaging. 75% of hospitals in our study do not perform computed tomography dose index measurements and 89% of centers do not perform patient dose measurements. Moreover, only 29% physicists believe IGRT dose is additional radiation burden to patient. This study has brought into focus the need to design a national protocol for IGRT dose measurement and development of indigenous tools to perform IGRT dose measurements. PMID:26865758

  14. Intelligent Image Analysis for Image-Guided Laser Hair Removal and Skin Therapy

    NASA Technical Reports Server (NTRS)

    Walker, Brian; Lu, Thomas; Chao, Tien-Hsin

    2012-01-01

    We present the development of advanced automatic target recognition (ATR) algorithms for the hair follicles identification in digital skin images to accurately direct the laser beam to remove the hair. The ATR system first performs a wavelet filtering to enhance the contrast of the hair features in the image. The system then extracts the unique features of the targets and sends the features to an Adaboost based classifier for training and recognition operations. The ATR system automatically classifies the hair, moles, or other skin lesion and provides the accurate coordinates of the intended hair follicle locations. The coordinates can be used to guide a scanning laser to focus energy only on the hair follicles. The intended benefit would be to protect the skin from unwanted laser exposure and to provide more effective skin therapy.

  15. Intelligent image analysis for image-guided hair removal and skin therapy

    NASA Astrophysics Data System (ADS)

    Walker, Brian; Lu, Thomas; Chao, Tien-Hsin

    2012-02-01

    We present the development of advanced automatic target recognition (ATR) algorithms for the hair follicles identification in digital skin images to accurately direct the laser beam to remove the hair. The ATR system first performs a wavelet filtering to enhance the contrast of the hair features in the image. The system then extracts the unique features of the targets and sends the features to an Adaboost based classifier for training and recognition operations. The ATR system automatically classifies the hair, moles, or other skin lesion and provides the accurate coordinates of the intended hair follicle locations. The coordinates can be used to guide a scanning laser to focus energy only on the hair follicles. The intended benefit would be to protect the skin from unwanted laser exposure and to provide more effective skin therapy.

  16. The first VLBI image of an infrared-faint radio source

    NASA Astrophysics Data System (ADS)

    Middelberg, E.; Norris, R. P.; Tingay, S.; Mao, M. Y.; Phillips, C. J.; Hotan, A. W.

    2008-11-01

    Context: We investigate the joint evolution of active galactic nuclei and star formation in the Universe. Aims: In the 1.4 GHz survey with the Australia Telescope Compact Array of the Chandra Deep Field South and the European Large Area ISO Survey - S1 we have identified a class of objects which are strong in the radio but have no detectable infrared and optical counterparts. This class has been called Infrared-Faint Radio Sources, or IFRS. 53 sources out of 2002 have been classified as IFRS. It is not known what these objects are. Methods: To address the many possible explanations as to what the nature of these objects is we have observed four sources with the Australian Long Baseline Array. Results: We have detected and imaged one of the four sources observed. Assuming that the source is at a high redshift, we find its properties in agreement with properties of Compact Steep Spectrum sources. However, due to the lack of optical and infrared data the constraints are not particularly strong.

  17. AO Observations of Three Powerful Radio Galaxies

    SciTech Connect

    de Vries, W; van Bruegel, W; Quirrenbach, A

    2002-08-01

    The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large galaxies are formed in a hierarchical way by multiple merger events, radio galaxies at low redshift represent the end-products of this process. However, it is not clear why some of these massive ellipticals have associated radio emission, while others do not. Both are thought to contain SMBHs, with masses proportional to the total luminous mass in the bulge. It either implies every SMBH has recurrent radio-loud phases, and the radio-quiet galaxies happen to be in the ''low'' state, or that the radio galaxy nuclei are physically different from radio-quiet ones, i.e. by having a more massive SMBH for a given bulge mass. Here we present the first results from our adaptive optics imaging and spectroscopy pilot program on three nearby powerful radio galaxies. Initiating a larger, more systematic AO survey of radio galaxies (preferentially with Laser Guide Star equipped AO systems) has the potential of furthering our understanding of the physical properties of radio sources, their triggering, and their subsequent evolution.

  18. IMRT for Image-Guided Single Vocal Cord Irradiation

    SciTech Connect

    Osman, Sarah O.S.; Astreinidou, Eleftheria; Boer, Hans C.J. de; Keskin-Cambay, Fatma; Breedveld, Sebastiaan; Voet, Peter; Al-Mamgani, Abrahim; Heijmen, Ben J.M.; Levendag, Peter C.

    2012-02-01

    Purpose: We have been developing an image-guided single vocal cord irradiation technique to treat patients with stage T1a glottic carcinoma. In the present study, we compared the dose coverage to the affected vocal cord and the dose delivered to the organs at risk using conventional, intensity-modulated radiotherapy (IMRT) coplanar, and IMRT non-coplanar techniques. Methods and Materials: For 10 patients, conventional treatment plans using two laterally opposed wedged 6-MV photon beams were calculated in XiO (Elekta-CMS treatment planning system). An in-house IMRT/beam angle optimization algorithm was used to obtain the coplanar and non-coplanar optimized beam angles. Using these angles, the IMRT plans were generated in Monaco (IMRT treatment planning system, Elekta-CMS) with the implemented Monte Carlo dose calculation algorithm. The organs at risk included the contralateral vocal cord, arytenoids, swallowing muscles, carotid arteries, and spinal cord. The prescription dose was 66 Gy in 33 fractions. Results: For the conventional plans and coplanar and non-coplanar IMRT plans, the population-averaged mean dose {+-} standard deviation to the planning target volume was 67 {+-} 1 Gy. The contralateral vocal cord dose was reduced from 66 {+-} 1 Gy in the conventional plans to 39 {+-} 8 Gy and 36 {+-} 6 Gy in the coplanar and non-coplanar IMRT plans, respectively. IMRT consistently reduced the doses to the other organs at risk. Conclusions: Single vocal cord irradiation with IMRT resulted in good target coverage and provided significant sparing of the critical structures. This has the potential to improve the quality-of-life outcomes after RT and maintain the same local control rates.

  19. Radio imaging observations of hard x-ray microflares observed by RHESSI

    NASA Astrophysics Data System (ADS)

    Kundu, M.; Trottet, G.; Garaimov, V.; Grigis, P.

    We describe the properties of two sets of microflares observed simultaneously by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) in hard X-rays and by two radio imaging instruments--NoRH (Nobeyama Radio Heliograph) in microwaves (17 GHz) and NRH (Nancay Radio Heliograph) at metric wavelengths. The two sets of events occurred in two different time zones, and as a result we do not have simultaneous imaging data in microwaves and metric wavlengths for the same RHESSI events. We'll discuss four events--two observed by NoRH in microwaves and two observed by NRH in meter waves, along with RHESSI events. The microwave (17 GHz) events occurred in AR 9934 at 03:58 UT May 3, 2002 and at 05:08 UT May 4, 2002. We have detected microwave (17 & 34 GHz) emissions in association with RHESSI microflares in the energy range 3-50 keV. The microwave emission comes from footpoints for higher energies, and from the entire mini or small flaring loop for lower energies. The relative positions of microwaves and hard X-rays are as they should be in normal flares. Sometimes the two sources coincide, at other times the two sources are at opposite ends of the flaring loop. One sees the mini flaring loops clearly in NoRH images. RHESSI maps at the time of maximum X-ray emission during the event of May 3, 2002 clearly show an X-ray loop in the range 3-6 keV and two footpoints of the loop in the 6-12 and 12-25 keV ranges. These footpoints are located above opposite magnetic polarities as seen in overlays of hard X-ray images on the MDI images. The MDI magnetograms taken before the microflares show rapid evolution of the magnetic field, including sometimes the emergence of a new region. The hard X-ray spectrum of microwave associated RHESSI microflares can be fit by a thermal component (EM ˜ 3× 1046 cm-3) at low energies (3-6 keV) and a nonthermal component (with slope -3.2) at higher energies. The two metric events imaged by NRH occurred on August 5 and September 3, 2003, one located on

  20. Major Bleeding after Percutaneous Image-Guided Biopsies: Frequency, Predictors, and Periprocedural Management

    PubMed Central

    Kennedy, Sean A.; Milovanovic, Lazar; Midia, Mehran

    2015-01-01

    Major bleeding remains an uncommon yet potentially devastating complication following percutaneous image-guided biopsy. This article reviews two cases of major bleeding after percutaneous biopsy and discusses the frequency, predictors, and periprocedural management of major postprocedural bleeding. PMID:25762845

  1. Endoscopic image-guided thermal therapy using targeted near infrared fluorescent gold nanorods (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Elson, Daniel S.

    2016-09-01

    We present an in vivo study of endoscopic fluorescence image-guided photothermal therapy of human oesophageal adenocarcinoma in a murine xenograft model, using intratumoural or intravenous gold nanorods functionalised with Cy5.5 and EGFR.

  2. MO-DE-202-02: Advances in Image Registration and Reconstruction for Image-Guided Neurosurgery.

    PubMed

    Siewerdsen, J

    2016-06-01

    At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: (1) Keyvan Farahani, "Image-guided focused ultrasound surgery and therapy" (2) Jeffrey H. Siewerdsen, "Advances in image registration and reconstruction for image-guided neurosurgery" (3) Tina Kapur, "Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite" (4) Raj Shekhar, "Multimodality image-guided interventions: Multimodality for the rest of us" Learning Objectives: 1. Understand the principles and applications of HIFU in surgical ablation. 2. Learn about recent advances in 3D-2D and 3D deformable image registration in support of surgical safety and precision. 3. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. 4. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. 5. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and

  3. Engineering Melanin Nanoparticles as an Efficient Drug-Delivery System for Imaging-Guided Chemotherapy.

    PubMed

    Zhang, Ruiping; Fan, Quli; Yang, Min; Cheng, Kai; Lu, Xiaomei; Zhang, Lei; Huang, Wei; Cheng, Zhen

    2015-09-09

    In order to promote imaging-guided chemotherapy for preclinical and clinical applications, endogenous nanosystems with both contrast and drug-delivery properties are highly desired. Here, the simple use of melanin is first reported, and this biopolymer with good biocompatibility and biodegradability, binding ability to drugs and ions, and intrinsic photoacoustic properties, can serve as an efficient endogenous nanosystem for imaging-guided tumor chemotherapy in living mice.

  4. Direction-Dependent Effects In Wide-Field Wideband Full-Stokes Radio Imaging

    NASA Astrophysics Data System (ADS)

    Jagannathan, P.; Bhatanagar, S.; Rau, U.; Taylor, R.

    2015-09-01

    Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction-dependent (DD) gains.The antenna power pattern varies both as a function of time and frequency. The broad-band time varying nature of the antenna power pattern when not corrected leads to gross errors in full Stokes imaging and flux estimation. In this poster we explore the errors that arise in image deconvolution while not accounting for the time and frequency dependence of the antenna power pattern. Simulations were conducted with the wide-band full Stokes power pattern of the Karl G. Jansky Very Large Array (VLA) antennas to demonstrate the level of errors arising from direction-dependent gains and their non-neglegible impact on upcoming sky surveys such as the VLASS. DD corrections through hybrid projection algorithms are computationally expensive to perform. A highly parallel implementation through high performance computing architectures is the only feasible way of applying these corrections to the large data sizes of these upcoming surveys.

  5. TU-D-BRD-01: Image Guided SBRT II: Challenges ' Pitfalls

    SciTech Connect

    Chang, Z; Yin, F; Cho, J

    2014-06-15

    Stereotactic body radiation therapy (SBRT) has been effective treatment for the management of various diseases, which often delivers high radiation dose in a single or a few fractions. SBRT therefore demands precise treatment delivery to the tumor while sparing adjacent healthy tissue. Recent developments in image guidance enable target localization with increased accuracy. With such improvements in localization, image-guided SBRT has been widely adopted into clinical practice. In SBRT, high radiation dose is generally delivered with small fields. Therefore, it is crucial to accurately measure dosimetric data for the small fields during commissioning. In addition, image-guided SBRT demands accurate image localization to ensure safety and quality of patient care. Lately, the reports of AAPM TG 142 and TG 104 have been published and added recommendations for imaging devices that are integrated with the linear accelerator for SBRT. Furthermore, various challenges and potential pitfalls lie in the clinical implementation of image-guided SBRT. In this lecture, these challenges and pitfalls of image-guided SBRT will be illustrated and discussed from dosimetric, technical and clinical perspectives.Being a promising technique, image-guided SBRT has shown great potentials, and will lead to more accurate and safer SBRT treatments. Learning Objectives: To understand dosimetric challenges and pitfalls for IGRT application in SBRT. To understand major clinical challenges and pitfalls for IGRT application in SBRT. To understand major technical challenges and pitfalls for IGRT application in SBRT.

  6. Integration of patient specific modeling and advanced image processing techniques for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Archip, Neculai; Fedorov, Andriy; Lloyd, Bryn; Chrisochoides, Nikos; Golby, Alexandra; Black, Peter M.; Warfield, Simon K.

    2006-03-01

    A major challenge in neurosurgery oncology is to achieve maximal tumor removal while avoiding postoperative neurological deficits. Therefore, estimation of the brain deformation during the image guided tumor resection process is necessary. While anatomic MRI is highly sensitive for intracranial pathology, its specificity is limited. Different pathologies may have a very similar appearance on anatomic MRI. Moreover, since fMRI and diffusion tensor imaging are not currently available during the surgery, non-rigid registration of preoperative MR with intra-operative MR is necessary. This article presents a translational research effort that aims to integrate a number of state-of-the-art technologies for MRI-guided neurosurgery at the Brigham and Women's Hospital (BWH). Our ultimate goal is to routinely provide the neurosurgeons with accurate information about brain deformation during the surgery. The current system is tested during the weekly neurosurgeries in the open magnet at the BWH. The preoperative data is processed, prior to the surgery, while both rigid and non-rigid registration algorithms are run in the vicinity of the operating room. The system is tested on 9 image datasets from 3 neurosurgery cases. A method based on edge detection is used to quantitatively validate the results. 95% Hausdorff distance between points of the edges is used to estimate the accuracy of the registration. Overall, the minimum error is 1.4 mm, the mean error 2.23 mm, and the maximum error 3.1 mm. The mean ratio between brain deformation estimation and rigid alignment is 2.07. It demonstrates that our results can be 2.07 times more precise then the current technology. The major contribution of the presented work is the rigid and non-rigid alignment of the pre-operative fMRI with intra-operative 0.5T MRI achieved during the neurosurgery.

  7. Global VLBI Observations of Weak Extragalactic Radio Sources: Imaging Candidates to Align the VLBI and Gaia Frames

    NASA Technical Reports Server (NTRS)

    Bourda, Geraldine; Collioud, Arnaud; Charlot, Patrick; Porcas, Richard; Garrington, Simon

    2010-01-01

    The space astrometry mission Gaia will construct a dense optical QSO-based celestial reference frame. For consistency between optical and radio positions, it will be important to align the Gaia and VLBI frames (International Celestial Reference Frame) with the highest accuracy. In this respect, it is found that only 10% of the ICRF sources are suitable to establish this link (70 sources), either because most of the ICRF sources are not bright enough at optical wavelengths or because they show extended radio emission which precludes reaching the highest astrometric accuracy. In order to improve the situation, we initiated a multi-step VLBI observational project, dedicated to finding additional suitable radio sources for aligning the two frames. The sample consists of about 450 optically-bright radio sources, typically 20 times weaker than the ICRF sources, which have been selected by cross-correlating optical and radio catalogs. The initial observations, aimed at checking whether these sources are detectable with VLBI, and conducted with the European VLBI Network (EVN) in 2007, showed an excellent 90% detection rate. This paper reports on global VLBI observations carried out in March 2008 to image 105 from the 398 previously detected sources. All sources were successfully imaged, revealing compact VLBI structure for about half of them, which is very promising for the future.

  8. Hands-free, Wireless Goggles for Near-infrared Fluorescence and Real-time Image-guided Surgery

    PubMed Central

    Liu, Yang; Bauer, Adam Q.; Akers, Walter; Sudlow, Gail; Liang, Kexian; Shen, Duanwen; Berezin, Mikhail; Culver, Joseph P.; Achilefu, Samuel

    2011-01-01

    Background Current cancer management faces several challenges, including the occurrence of residual tumor after resection, the use of radioactive materials or high concentrations of blue dyes for sentinel lymph node (SLN) biopsy, and use of bulky systems in surgical suites for image guidance. To overcome these limitations, we developed a real-time intraoperative imaging device that, when combined with near infrared (NIR) fluorescent molecular probes, can aid identification of tumor margins, guide surgical resections, map SLNs, and transfer acquired data wirelessly for remote analysis. Methods We developed a new compact, wireless, wearable, and battery-operated device that allows hands-free operation by surgeons. A CCD-based consumer-grade night vision viewer was used to develop the detector portion of the device and the light source portion was developed from a compact headlamp. This piece was retrofitted to provide both NIR excitation and white light illumination simultaneously. Wireless communication was enabled by integrating a battery-operated miniature radio-frequency video transmitter into the system. We applied the device in several types of oncologic surgical procedures in murine models, including SLN mapping, fluorescence-guided tumor resection, and surgery under remote expert guidance. Results Unlike conventional imaging instruments, the device directly displays fluorescence information on its eyepiece. When employed in SLN mapping, the locations of SLNs were clearly visualized, even with tracer level dosing of a NIR fluorescent dye, indocyanine green. When utilized in tumor resection, tumor margins and small nodules not visible to the naked eye were readily visualized. In a simulated point-of-care setting, tumors were successfully located and removed under remote guidance using the wireless feature of the device. Importantly, the total cost of this prototype system ($1200) is significantly lower than existing imaging instruments. Conclusion Our results

  9. Image guided dose escalated prostate radiotherapy: still room to improve

    PubMed Central

    Martin, Jarad M; Bayley, Andrew; Bristow, Robert; Chung, Peter; Gospodarowicz, Mary; Menard, Cynthia; Milosevic, Michael; Rosewall, Tara; Warde, Padraig R; Catton, Charles N

    2009-01-01

    Background Prostate radiotherapy (RT) dose escalation has been reported to result in improved biochemical control at the cost of greater late toxicity. We report on the application of 79.8 Gy in 42 fractions of prostate image guided RT (IGRT). The primary objective was to assess 5-year biochemical control and potential prognostic factors by the Phoenix definition. Secondary endpoints included acute and late toxicity by the Radiotherapy Oncology Group (RTOG) scoring scales. Methods From October/2001 and June/2003, 259 men were treated with at least 2-years follow-up. 59 patients had low, 163 intermediate and 37 high risk disease. 43 had adjuvant hormonal therapy (HT), mostly for high- or multiple risk factor intermediate-risk disease (n = 25). They received either 3-dimensional conformal RT (3DCRT, n = 226) or intensity modulated RT (IMRT) including daily on-line IGRT with intraprostatic fiducial markers. Results Median follow-up was 67.8 months (range 24.4-84.7). There was no severe (grade 3-4) acute toxicity, and grade 2 acute gastrointestinal (GI) toxicity was unusual (10.1%). The 5-year incidence of grade 2-3 late GI and genitourinary (GU) toxicity was 13.7% and 12.1%, with corresponding grade 3 figures of 3.5% and 2.0% respectively. HT had an association with an increased risk of grade 2-3 late GI toxicity (11% v 21%, p = 0.018). Using the Phoenix definition for biochemical failure, the 5 year-bNED is 88.4%, 76.5% and 77.9% for low, intermediate and high risk patients respectively. On univariate analysis, T-category and Gleason grade correlated with Phoenix bNED (p = 0.006 and 0.039 respectively). Hormonal therapy was not a significant prognostic factor on uni- or multi-variate analysis. Men with positive prostate biopsies following RT had a lower chance of bNED at 5 years (34.4% v 64.3%; p = 0.147). Conclusion IGRT to 79.8 Gy results in favourable rates of late toxicity compared with published non-IGRT treated cohorts. Future avenues of investigation for

  10. Image-guided radiotherapy and motion management in lung cancer

    PubMed Central

    2015-01-01

    In this review, image guidance and motion management in radiotherapy for lung cancer is discussed. Motion characteristics of lung tumours and image guidance techniques to obtain motion information are elaborated. Possibilities for management of image guidance and motion in the various steps of the treatment chain are explained, including imaging techniques and beam delivery techniques. Clinical studies using different motion management techniques are reviewed, and finally future directions for image guidance and motion management are outlined. PMID:25955231

  11. Magnetic resonance image-guided versus ultrasound-guided high-intensity focused ultrasound in the treatment of breast cancer

    PubMed Central

    Li, Sheng; Wu, Pei-Hong

    2013-01-01

    Image-guided high-intensity focused ultrasound (HIFU) has been used for more than ten years, primarily in the treatment of liver and prostate cancers. HIFU has the advantages of precise cancer ablation and excellent protection of healthy tissue. Breast cancer is a common cancer in women. HIFU therapy, in combination with other therapies, has the potential to improve both oncologic and cosmetic outcomes for breast cancer patients by providing a curative therapy that conserves mammary shape. Currently, HIFU therapy is not commonly used in breast cancer treatment, and efforts to promote the application of HIFU is expected. In this article, we compare different image-guided models for HIFU and reviewed the status, drawbacks, and potential of HIFU therapy for breast cancer. PMID:23237221

  12. Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Shieh, Chun-Chien; Keall, Paul J.; Kuncic, Zdenka; Huang, Chen-Yu; Feain, Ilana

    2015-12-01

    The ability to monitor tumor motion without implanted markers is clinically advantageous for lung image-guided radiotherapy (IGRT). Existing markerless tracking methods often suffer from overlapping structures and low visibility of tumors on kV projection images. We introduce the short arc tumor tracking (SATT) method to overcome these issues. The proposed method utilizes multiple kV projection images selected from a nine-degree imaging arc to improve tumor localization, and respiratory-correlated 4D cone-beam CT (CBCT) prior knowledge to minimize the effects of overlapping anatomies. The 3D tumor position is solved as an optimization problem with prior knowledge incorporated via regularization. We retrospectively validated SATT on 11 clinical scans from four patients with central tumors. These patients represent challenging scenarios for markerless tumor tracking due to the inferior adjacent contrast. The 3D trajectories of implanted fiducial markers were used as the ground truth for tracking accuracy evaluation. In all cases, the tumors were successfully tracked at all gantry angles. Compared to standard pre-treatment CBCT guidance alone, trajectory errors were significantly smaller with tracking in all cases, and the improvements were the most prominent in the superior-inferior direction. The mean 3D tracking error ranged from 2.2-9.9 mm, which was 0.4-2.6 mm smaller compared to pre-treatment CBCT. In conclusion, we were able to directly track tumors with inferior visibility on kV projection images using SATT. Tumor localization accuracies are significantly better with tracking compared to the current standard of care of lung IGRT. Future work involves the prospective evaluation and clinical implementation of SATT.

  13. Optimizing MR imaging-guided navigation for focused ultrasound interventions in the brain

    NASA Astrophysics Data System (ADS)

    Werner, B.; Martin, E.; Bauer, R.; O'Gorman, R.

    2017-03-01

    MR imaging during transcranial MR imaging-guided Focused Ultrasound surgery (tcMRIgFUS) is challenging due to the complex ultrasound transducer setup and the water bolus used for acoustic coupling. Achievable image quality in the tcMRIgFUS setup using the standard body coil is significantly inferior to current neuroradiologic standards. As a consequence, MR image guidance for precise navigation in functional neurosurgical interventions using tcMRIgFUS is basically limited to the acquisition of MR coordinates of salient landmarks such as the anterior and posterior commissure for aligning a stereotactic atlas. Here, we show how improved MR image quality provided by a custom built MR coil and optimized MR imaging sequences can support imaging-guided navigation for functional tcMRIgFUS neurosurgery by visualizing anatomical landmarks that can be integrated into the navigation process to accommodate for patient specific anatomy.

  14. THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz

    SciTech Connect

    Huffenberger, K. M.; Araujo, D.; Zwart, J. T. L.; Bischoff, C.; Buder, I.; Chinone, Y.; Hasegawa, M.; Cleary, K.; Monsalve, R.; Næss, S. K.; Newburgh, L. B.; Reeves, R.; Ruud, T. M.; Eriksen, H. K.; Wehus, I. K.; Gaier, T.; Dickinson, C.; Gundersen, J. O.; Collaboration: QUIET Collaboration; and others

    2015-06-10

    We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30–40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%–20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps.

  15. The Q/U Imaging Experiment: Polarization Measurements of Radio Sources at 43 and 95 GHz

    NASA Astrophysics Data System (ADS)

    Huffenberger, K. M.; Araujo, D.; Bischoff, C.; Buder, I.; Chinone, Y.; Cleary, K.; Kusaka, A.; Monsalve, R.; Næss, S. K.; Newburgh, L. B.; Reeves, R.; Ruud, T. M.; Wehus, I. K.; Zwart, J. T. L.; Dickinson, C.; Eriksen, H. K.; Gaier, T.; Gundersen, J. O.; Hasegawa, M.; Hazumi, M.; Miller, A. D.; Radford, S. J. E.; Readhead, A. C. S.; Staggs, S. T.; Tajima, O.; Thompson, K. L.; QUIET Collaboration

    2015-06-01

    We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ˜480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30-40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%-20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps.

  16. User guide to the Magellan synthetic aperture radar images

    NASA Technical Reports Server (NTRS)

    Wall, Stephen D.; Mcconnell, Shannon L.; Leff, Craig E.; Austin, Richard S.; Beratan, Kathi K.; Rokey, Mark J.

    1995-01-01

    The Magellan radar-mapping mission collected a large amount of science and engineering data. Now available to the general scientific community, this data set can be overwhelming to someone who is unfamiliar with the mission. This user guide outlines the mission operations and data set so that someone working with the data can understand the mapping and data-processing techniques used in the mission. Radar-mapping parameters as well as data acquisition issues are discussed. In addition, this user guide provides information on how the data set is organized and where specific elements of the set can be located.

  17. Deep Interior Mission: Imaging the Interior of Near-Earth Asteroids Using Radio Reflection Tomography

    NASA Technical Reports Server (NTRS)

    Safaeinili, A.; Asphaug, E.; Rodriquez, E.; Gurrola, E.; Belton, M.; Klaasen, K.; Ostro, S.; Plaut, J.; Yeomans, D.

    2005-01-01

    Near-Earth asteroids are important exploration targets since they provide clues to the evolution of the solar system. They are also of interest since they present a clear danger to Earth. Our mission objective is to image the internal structure of two NEOs using radio reflection tomography (RRT) in order to explore the record of asteroid origin and impact evolution, and to test the fundamental hypothesis that some NEOs are rubble piles rather than consolidated bodies. Our mission s RRT technique is analogous to doing a CAT scan of the asteroid from orbit. Closely sampled radar echoes are processed to yield volumetric maps of mechanical and compositional boundaries, and to measure interior material dielectric properties. The RRT instrument is a radar that operates at 5 and 15 MHz with two 30-m (tip-to-tip) dipole antennas that are used in a cross-dipole configuration. The radar transmitter and receiver electronics have heritage from JPL's MARSIS contribution to Mars Express, and the antenna is similar to systems used in IMAGE and LACE missions. The 5-MHz channel is designed to penetrate greater than 1 km of basaltic rock, and 15-MHz penetrates a few hundred meters or more. In addition to RRT volumetric imaging, we use redundant color cameras to explore the surface expressions of unit boundaries, in order to relate interior radar imaging to what is observable from spacecraft imaging and from Earth. The camera also yields stereo color imaging for geology and RRT-related compositional analysis. Gravity and high fidelity geodesy are used to explore how interior structure is expressed in shape, density, mass distribution and spin. Ion thruster propulsion is utilized by Deep Interior to enable tomographic radar mapping of multiple asteroids. Within the Discovery AO scheduling parameters we identify two targets, S-type 1999 ND43 (approximately 500 m diameter) and V-type 3908 Nyx (approximately 1 km), asteroids whose compositions bracket the diversity of solar system

  18. Tissue deformation and shape models in image-guided interventions: a discussion paper.

    PubMed

    Hawkes, D J; Barratt, D; Blackall, J M; Chan, C; Edwards, P J; Rhode, K; Penney, G P; McClelland, J; Hill, D L G

    2005-04-01

    This paper promotes the concept of active models in image-guided interventions. We outline the limitations of the rigid body assumption in image-guided interventions and describe how intraoperative imaging provides a rich source of information on spatial location of anatomical structures and therapy devices, allowing a preoperative plan to be updated during an intervention. Soft tissue deformation and variation from an atlas to a particular individual can both be determined using non-rigid registration. Established methods using free-form deformations have a very large number of degrees of freedom. Three examples of deformable models--motion models, biomechanical models and statistical shape models--are used to illustrate how prior information can be used to restrict the number of degrees of freedom of the registration algorithm and thus provide active models for image-guided interventions. We provide preliminary results from applications for each type of model.

  19. From Medical Image Computing to Computer Aided Intervention: Development of a Research Interface for Image Guided Navigation

    PubMed Central

    Papademetris, Xenophon; DeLorenzo, Christine; Flossmann, Sven; Neff, Markus; Vives, Kenneth P.; Spencer, Dennis D.; Staib, Lawrence H.; Duncan, James S.

    2009-01-01

    Background This paper describes the development and application of a research interface to integrate research image analysis software with a commercial image guided surgery navigation system. This interface enables bi-directional transfer of data such as images, visualizations and tool positions in real time. Methods We describe both the design and the application programming interface of the research interface, as well as show the function of an example client program. The resulting interface provides a practical and versatile link for bringing image analysis research techniques into the operating room (OR). Results We present examples from the successful use of this research interface in both phantom experiments and in real neurosurgeries. In particular we demonstrate that the integrated dual-computer system achieves tool tracking performance that is comparable to the more typical single-computer scenario. Conclusions Network interfaces for this type are viable solutions for the integration of commercial image-guided navigation systems and research software. PMID:19301361

  20. Image-guided macular laser therapy: design considerations and progress toward implementation

    NASA Astrophysics Data System (ADS)

    Berger, Jeffrey W.; Shin, David S.

    1999-06-01

    Laser therapy is currently the only treatment of proven benefit for exudative age related macular degeneration and diabetic retinopathy. To guide treatment for macular diseases, investigations were initiated to permit overlay of previously-stored angiographic images and image sequences superimposed onto the real-time biomicroscopic fundus image. Prior to treatment, a set of partially overlapping fundus images is acquired and montaged in order to provide a map for subsequent tracking operations. A binocular slit-lamp biomicroscope interfaced to a CCD camera, framegrabber board, and PC permits acquisition and rendering of retinal images. Computer-vision algorithms facilitate robust tracking, registration, and near-video-rate image overlay of previously-stored retinal photographic and angiographic images onto the real-time fundus image. Laser treatment is guided in this augmented reality environment where the borders of the treatment target--for example, the boundaries of a choroidal neovascularization complex--are easily identified through overlay of angiographic information superimposed on, and registered with, the real-time fundus image. During periods of misregistration as judged by the amplitude of the tracking similarity metric, laser function is disabled, affording additional safety. Image-guided macular laser therapy should facilitate accurate targeting of treatable lesions and less unintentional retinal injury when compared with standard techniques.

  1. Fast CT-CT fluoroscopy registration with respiratory motion compensation for image-guided lung intervention

    NASA Astrophysics Data System (ADS)

    Su, Po; Xue, Zhong; Lu, Kongkuo; Yang, Jianhua; Wong, Stephen T.

    2012-02-01

    CT-fluoroscopy (CTF) is an efficient imaging method for guiding percutaneous lung interventions such as biopsy. During CTF-guided biopsy procedure, four to ten axial sectional images are captured in a very short time period to provide nearly real-time feedback to physicians, so that they can adjust the needle as it is advanced toward the target lesion. Although popularly used in clinics, this traditional CTF-guided intervention procedure may require frequent scans and cause unnecessary radiation exposure to clinicians and patients. In addition, CTF only generates limited slices of images and provides limited anatomical information. It also has limited response to respiratory movements and has narrow local anatomical dynamics. To better utilize CTF guidance, we propose a fast CT-CTF registration algorithm with respiratory motion estimation for image-guided lung intervention using electromagnetic (EM) guidance. With the pre-procedural exhale and inhale CT scans, it would be possible to estimate a series of CT images of the same patient at different respiratory phases. Then, once a CTF image is captured during the intervention, our algorithm can pick the best respiratory phase-matched 3D CT image and performs a fast deformable registration to warp the 3D CT toward the CTF. The new 3D CT image can be used to guide the intervention by superimposing the EM-guided needle location on it. Compared to the traditional repetitive CTF guidance, the registered CT integrates both 3D volumetric patient data and nearly real-time local anatomy for more effective and efficient guidance. In this new system, CTF is used as a nearly real-time sensor to overcome the discrepancies between static pre-procedural CT and the patient's anatomy, so as to provide global guidance that may be supplemented with electromagnetic (EM) tracking and to reduce the number of CTF scans needed. In the experiments, the comparative results showed that our fast CT-CTF algorithm can achieve better registration

  2. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Slot Thing, Rune; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-01

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.

  3. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy.

    PubMed

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto; Hansen, Olfred; Brink, Carsten

    2016-08-07

    A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.

  4. Image-guided Treatment in the Hepatobiliary System: Role of Imaging in Treatment Planning and Posttreatment Evaluation.

    PubMed

    Bajpai, Surabhi; Kambadakone, Avinash; Guimaraes, Alexander R; Arellano, Ronald S; Gervais, Debra A; Sahani, Dushyant

    2015-01-01

    In the past decade, image-guided targeted treatments such as percutaneous ablation, intra-arterial embolic therapies, and targeted radiation therapy have shown substantial promise in management of hepatobiliary malignancies. Imaging is integral to patient selection, treatment delivery, and assessment of treatment effectiveness. Preprocedural imaging is crucial and allows local tumor staging, evaluation of surrounding structures, and selection of suitable therapeutic options and strategies for treatment delivery. Postprocedural imaging is required to monitor therapeutic success, detect residual or recurrent disease, and identify procedure-related complications to guide appropriate future therapy. Technical innovations in cross-sectional imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging, combined with advances in image postprocessing and new types of contrast agents, allow precise morphologic assessment and functional evaluation of hepatobiliary tumors. Advanced postprocessing techniques such as image fusion and volumetric assessment not only facilitate procedural planning and treatment delivery but also enhance posttreatment imaging surveillance. In addition, molecular imaging techniques such as fluorodeoxyglucose positron emission tomography (PET), PET/CT, and PET/MR imaging offer opportunities to evaluate various physiologic properties of tumors.

  5. [Film-less digital x-ray image processing--new prospects with the RadioVisioGraphy equipment].

    PubMed

    Mairgünther, R H

    1994-01-01

    Due to a new removable and compatible mass storage media, the ultimate model of the RadioVisioGraphy (RVG) system for X-ray recording without films offers an adequate possibility to store images as well as an easy way to transfer these data to other personal computers for digital image processing. By experiment we demonstrated a digital image subtraction procedure with public domain software, simulating a situation before and after apicoectomy. The result shows a good quality with a favourable relation between signal and noise.

  6. Radio Jove: Jupiter Radio Astronomy for Citizens

    NASA Astrophysics Data System (ADS)

    Higgins, Charles; Thieman, J. R.; Flagg, R.; Reyes, F. J.; Sky, J.; Greenman, W.; Brown, J.; Typinski, D.; Ashcraft, T.; Mount, A.

    2014-01-01

    Radio JOVE is a hands-on educational activity that brings the radio sounds of the Sun, Jupiter, the Milky Way Galaxy, and terrestrial radio noise to students, teachers, and the general public. Participants may build a simple radio telescope kit, make scientific observations, and interact with professional radio observatories in real-time over the Internet. Our website (http://radiojove.gsfc.nasa.gov) includes science information, construction manuals, observing guides, and education resources for teachers and students. Radio Jove is continually expanding its participants with over 1800 kits sold to more than 70 countries worldwide. Recently some of our most dedicated observers have upgraded their Radio Jove antennas to semi-professional observatories. We have spectrographs and wide band antennas, some with 8 MHz bandwidth and some with dual polarization capabilities. In an effort to add to the science literature, these observers are coordinating their efforts to pursue some basic questions about Jupiter’s radio emissions (radio source locations, spectral structure, long term changes, etc.). We can compare signal and ionosphere variations using the many Radio Jove observers at different locations. Observers are also working with members of the Long Wavelength Array Station 1 (LWA1) radio telescope to coordinate observations of Jupiter; Radio Jove is planning to make coordinated observations while the Juno Mission is active beginning in 2015. The Radio Jove program is overviewed, its hardware and software are highlighted, recent sample observations are shown, and we demonstrate that we are capable of real citizen science.

  7. Technique for Targeting Arteriovenous Malformations Using Frameless Image-Guided Robotic Radiosurgery

    SciTech Connect

    Hristov, Dimitre; Liu, Lina; Adler, John R.; Gibbs, Iris C.; Moore, Teri; Sarmiento, Marily; Chang, Steve D.; Dodd, Robert; Marks, Michael; Do, Huy M.

    2011-03-15

    Purpose: To integrate three-dimensional (3D) digital rotation angiography (DRA) and two-dimensional (2D) digital subtraction angiography (DSA) imaging into a targeting methodology enabling comprehensive image-guided robotic radiosurgery of arteriovenous malformations (AVMs). Methods and Materials: DRA geometric integrity was evaluated by imaging a phantom with embedded markers. Dedicated DSA acquisition modes with preset C-arm positions were configured. The geometric reproducibility of the presets was determined, and its impact on localization accuracy was evaluated. An imaging protocol composed of anterior-posterior and lateral DSA series in combination with a DRA run without couch displacement between acquisitions was introduced. Software was developed for registration of DSA and DRA (2D-3D) images to correct for: (a) small misalignments of the C-arm with respect to the estimated geometry of the set positions and (b) potential patient motion between image series. Within the software, correlated navigation of registered DRA and DSA images was incorporated to localize AVMs within a 3D image coordinate space. Subsequent treatment planning and delivery followed a standard image-guided robotic radiosurgery process. Results: DRA spatial distortions were typically smaller than 0.3 mm throughout a 145-mm x 145-mm x 145-mm volume. With 2D-3D image registration, localization uncertainties resulting from the achievable reproducibility of the C-arm set positions could be reduced to about 0.2 mm. Overall system-related localization uncertainty within the DRA coordinate space was 0.4 mm. Image-guided frameless robotic radiosurgical treatments with this technique were initiated. Conclusions: The integration of DRA and DSA into the process of nidus localization increases the confidence with which radiosurgical ablation of AVMs can be performed when using only an image-guided technique. Such an approach can increase patient comfort, decrease time pressure on clinical and

  8. 3D Image-Guided Automatic Pipette Positioning for Single Cell Experiments in vivo

    PubMed Central

    Long, Brian; Li, Lu; Knoblich, Ulf; Zeng, Hongkui; Peng, Hanchuan

    2015-01-01

    We report a method to facilitate single cell, image-guided experiments including in vivo electrophysiology and electroporation. Our method combines 3D image data acquisition, visualization and on-line image analysis with precise control of physical probes such as electrophysiology microelectrodes in brain tissue in vivo. Adaptive pipette positioning provides a platform for future advances in automated, single cell in vivo experiments. PMID:26689553

  9. Investigation of radio astronomy image processing techniques for use in the passive millimetre-wave security screening environment

    NASA Astrophysics Data System (ADS)

    Taylor, Christopher T.; Hutchinson, Simon; Salmon, Neil A.; Wilkinson, Peter N.; Cameron, Colin D.

    2014-06-01

    Image processing techniques can be used to improve the cost-effectiveness of future interferometric Passive MilliMetre Wave (PMMW) imagers. The implementation of such techniques will allow for a reduction in the number of collecting elements whilst ensuring adequate image fidelity is maintained. Various techniques have been developed by the radio astronomy community to enhance the imaging capability of sparse interferometric arrays. The most prominent are Multi- Frequency Synthesis (MFS) and non-linear deconvolution algorithms, such as the Maximum Entropy Method (MEM) and variations of the CLEAN algorithm. This investigation focuses on the implementation of these methods in the defacto standard for radio astronomy image processing, the Common Astronomy Software Applications (CASA) package, building upon the discussion presented in Taylor et al., SPIE 8362-0F. We describe the image conversion process into a CASA suitable format, followed by a series of simulations that exploit the highlighted deconvolution and MFS algorithms assuming far-field imagery. The primary target application used for this investigation is an outdoor security scanner for soft-sided Heavy Goods Vehicles. A quantitative analysis of the effectiveness of the aforementioned image processing techniques is presented, with thoughts on the potential cost-savings such an approach could yield. Consideration is also given to how the implementation of these techniques in CASA might be adapted to operate in a near-field target environment. This may enable a much wider usability by the imaging community outside of radio astronomy and thus would be directly relevant to portal screening security systems in the microwave and millimetre wave bands.

  10. Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFAR.

    PubMed

    Broderick, J W; Fender, R P; Breton, R P; Stewart, A J; Rowlinson, A; Swinbank, J D; Hessels, J W T; Staley, T D; van der Horst, A J; Bell, M E; Carbone, D; Cendes, Y; Corbel, S; Eislöffel, J; Falcke, H; Grießmeier, J-M; Hassall, T E; Jonker, P; Kramer, M; Kuniyoshi, M; Law, C J; Markoff, S; Molenaar, G J; Pietka, M; Scheers, L H A; Serylak, M; Stappers, B W; Ter Veen, S; van Leeuwen, J; Wijers, R A M J; Wijnands, R; Wise, M W; Zarka, P

    2016-07-01

    The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks - six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν(-0.4)), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.

  11. Phased Array Beamforming and Imaging in Composite Laminates Using Guided Waves

    NASA Technical Reports Server (NTRS)

    Tian, Zhenhua; Leckey, Cara A. C.; Yu, Lingyu

    2016-01-01

    This paper presents the phased array beamforming and imaging using guided waves in anisotropic composite laminates. A generic phased array beamforming formula is presented, based on the classic delay-and-sum principle. The generic formula considers direction-dependent guided wave properties induced by the anisotropic material properties of composites. Moreover, the array beamforming and imaging are performed in frequency domain where the guided wave dispersion effect has been considered. The presented phased array method is implemented with a non-contact scanning laser Doppler vibrometer (SLDV) to detect multiple defects at different locations in an anisotropic composite plate. The array is constructed of scan points in a small area rapidly scanned by the SLDV. Using the phased array method, multiple defects at different locations are successfully detected. Our study shows that the guided wave phased array method is a potential effective method for rapid inspection of large composite structures.

  12. The management of imaging dose during image-guided radiotherapy: Report of the AAPM Task Group 75

    SciTech Connect

    Murphy, Martin J.; Balter, James; Balter, Stephen; BenComo, Jose A. Jr.; Das, Indra J.; Jiang, Steve B.; Ma, C.-M.; Olivera, Gustavo H.; Rodebaugh, Raymond F.; Ruchala, Kenneth J.; Shirato, Hiroki; Yin, Fang-Fang

    2007-10-15

    Radiographic image guidance has emerged as the new paradigm for patient positioning, target localization, and external beam alignment in radiotherapy. Although widely varied in modality and method, all radiographic guidance techniques have one thing in common--they can give a significant radiation dose to the patient. As with all medical uses of ionizing radiation, the general view is that this exposure should be carefully managed. The philosophy for dose management adopted by the diagnostic imaging community is summarized by the acronym ALARA, i.e., as low as reasonably achievable. But unlike the general situation with diagnostic imaging and image-guided surgery, image-guided radiotherapy (IGRT) adds the imaging dose to an already high level of therapeutic radiation. There is furthermore an interplay between increased imaging and improved therapeutic dose conformity that suggests the possibility of optimizing rather than simply minimizing the imaging dose. For this reason, the management of imaging dose during radiotherapy is a different problem than its management during routine diagnostic or image-guided surgical procedures. The imaging dose received as part of a radiotherapy treatment has long been regarded as negligible and thus has been quantified in a fairly loose manner. On the other hand, radiation oncologists examine the therapy dose distribution in minute detail. The introduction of more intensive imaging procedures for IGRT now obligates the clinician to evaluate therapeutic and imaging doses in a more balanced manner. This task group is charged with addressing the issue of radiation dose delivered via image guidance techniques during radiotherapy. The group has developed this charge into three objectives: (1) Compile an overview of image-guidance techniques and their associated radiation dose levels, to provide the clinician using a particular set of image guidance techniques with enough data to estimate the total diagnostic dose for a specific

  13. A review of 3D/2D registration methods for image-guided interventions.

    PubMed

    Markelj, P; Tomaževič, D; Likar, B; Pernuš, F

    2012-04-01

    Registration of pre- and intra-interventional data is one of the key technologies for image-guided radiation therapy, radiosurgery, minimally invasive surgery, endoscopy, and interventional radiology. In this paper, we survey those 3D/2D data registration methods that utilize 3D computer tomography or magnetic resonance images as the pre-interventional data and 2D X-ray projection images as the intra-interventional data. The 3D/2D registration methods are reviewed with respect to image modality, image dimensionality, registration basis, geometric transformation, user interaction, optimization procedure, subject, and object of registration.

  14. Using Particle Imaging Velocimetry and Radio Frequency Identification to gain insights into erosion processes

    NASA Astrophysics Data System (ADS)

    Parsons, A. J.; Wainwright, J.; Cooper, J. R.; Onda, Y.; Long, E. J.; Hargrave, G.; Kitchener, B.

    2012-12-01

    Erosion is a particle-based phenomenon, yet most of current understanding and modelling of this process is based on bulk measurements rather than the movement of individual particles. However, the application of two new technologies allows improved insight into the entrainment, transport and deposition of individual particles and facilitates particle-based modelling of the particle-based process. In this presentation we provide insights into particle movement based upon laboratory experiments using particle imaging velocimetry (PIV) and radio frequency identification (RFID). PIV has been used in experiments in which single raindrops have fallen onto dry sand in order to track the trajectories of detached particles. By measuring the movement of individual particles our aim is to compute the proportion of rainfall energy that is used in particle detachment and transport, and the controls on this proportion. RFID tags embedded into resin to mimic sand-sized particles have been tracked under simulated rainfall applied to bare-soil plots. By covering and uncovering particles at different times during the experiments we have been able to produce distributions of travel distances of particles under conditions of rainfall detachment and transport, overland-flow detachment and transport and combined raindrop detachment and flow transport.

  15. Tunnel detection using radio imaging method at the Otay Mesa site

    SciTech Connect

    Mahrer, K.D.; Mondt, W.A.

    1994-12-31

    The authors demonstrated that Radio Imaging Method (RIM) surface-to-surface, borehole-to-surface, and borehole-to-borehole sensing technologies at the Otay Mesa test site east of San Diego, California could detect and delineate a horizontal 4 {times} 6-foot (cross-section) tunnel buried at a depth of approximately 45 feet. Utilizing monochromatic, continuous wave electromagnetic signals from a magnetic dipole source operating in the range between 22 kHz and 15 MHz, the authors confirmed the effectiveness of two general approaches: (1) mapping the electrical conductivity contrast between the country rock (sandstone) and the tunnel (i.e. the void and surrounding desiccation fractures) and (2) locating a cable (i.e. conductor) within and running the length of the tunnel from its induced, secondary radiation. Surface-to-surface RIM, utilizing a gradiometer receiver, mapped the two-dimensional, plan view location of the tunnel. Borehole-to-surface delineated both the depth and plan view location of the tunnel. Borehole-to-borehole RIM delineated the depth of the tunnel.

  16. A Guide to Analysing Tongue Motion from Ultrasound Images

    ERIC Educational Resources Information Center

    Stone, Maureen

    2005-01-01

    This paper is meant to be an introduction to and general reference for ultrasound imaging for new and moderately experienced users of the instrument. The paper consists of eight sections. The first explains how ultrasound works, including beam properties, scan types and machine features. The second section discusses image quality, including the…

  17. Detection of a Compact Radio Source near the Center of a Gravitational Lens: Quasar Image or Galactic Core?

    PubMed

    Gorenstein, M V; Shapiro, I I; Cohen, N L; Corey, B E; Falco, E E; Marcaide, J M; Rogers, A E; Whitney, A R; Porcas, R W; Preston, R A; Rius, A

    1983-01-07

    By use of a new, very sensitive interferometric system, a faint, compact radio source has been detected near the center of the galaxy that acts as the main part of a gravitational lens. This lens forms two previously discovered images of the quasar Q09S7+561, which lies in the direction of the constellation Ursa Major. The newly detected source has a core smaller than 0.002 arc second in diameter with a flux density of 0.6 +/- 0.1 millijansky at the 13-centimeter wavelength of the radio observations. This source could be the predicted third image of the transparent gravitational lens, the central core of the galaxy, or some combination of the two. It is not yet possible to choose reliably between these alternatives.

  18. Radio imaging spectroscopy of synchrotron emission associated with a CME on the 14th of August 2010

    NASA Astrophysics Data System (ADS)

    Bain, Hazel; Krucker, S.; Saint-Hilaire, P.; Raftery, C.

    2013-07-01

    We present Nancay Radioheliograph observations of a moving type IV solar radio burst which occurred in association with a CME on the 14th of August 2010. The event was well observed at extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory, the SWAP instrument onboard Proba2 and by the LASCO white light coronograph. The burst emission was found to be cospatial with the core of the CME. Using radio imaging spectroscopy we are able to characterize the underlying electron distribution and plasma parameters within the source. Fitted spectra reveal a clear power law component consistent with optically thin synchrotron emission from accelerated electrons trapped in the erupting flux rope. As is often observed in type IV bursts, polarization measurements show the source to be moderately polarized during the peak of the burst, before steadily increasing to around 70% as the brightness temperature of the burst decays.

  19. CALORIMETRY OF GRB 030329: SIMULTANEOUS MODEL FITTING TO THE BROADBAND RADIO AFTERGLOW AND THE OBSERVED IMAGE EXPANSION RATE

    SciTech Connect

    Mesler, Robert A.; Pihlstroem, Ylva M.

    2013-09-01

    We perform calorimetry on the bright gamma-ray burst GRB 030329 by fitting simultaneously the broadband radio afterglow and the observed afterglow image size to a semi-analytic MHD and afterglow emission model. Our semi-analytic method is valid in both the relativistic and non-relativistic regimes, and incorporates a model of the interstellar scintillation that substantially effects the broadband afterglow below 10 GHz. The model is fitted to archival measurements of the afterglow flux from 1 day to 8.3 yr after the burst. Values for the initial burst parameters are determined and the nature of the circumburst medium is explored. Additionally, direct measurements of the lateral expansion rate of the radio afterglow image size allow us to estimate the initial Lorentz factor of the jet.

  20. IGSTK: Framework and example application using an open source toolkit for image-guided surgery applications

    NASA Astrophysics Data System (ADS)

    Cheng, Peng; Zhang, Hui; Kim, Hee-su; Gary, Kevin; Blake, M. Brian; Gobbi, David; Aylward, Stephen; Jomier, Julien; Enquobahrie, Andinet; Avila, Rick; Ibanez, Luis; Cleary, Kevin

    2006-03-01

    Open source software has tremendous potential for improving the productivity of research labs and enabling the development of new medical applications. The Image-Guided Surgery Toolkit (IGSTK) is an open source software toolkit based on ITK, VTK, and FLTK, and uses the cross-platform tools CMAKE and DART to support common operating systems such as Linux, Windows, and MacOS. IGSTK integrates the basic components needed in surgical guidance applications and provides a common platform for fast prototyping and development of robust image-guided applications. This paper gives an overview of the IGSTK framework and current status of development followed by an example needle biopsy application to demonstrate how to develop an image-guided application using this toolkit.

  1. Magnetic Resonance Imaging-Ultrasound Fusion-Guided Prostate Biopsy: Review of Technology, Techniques, and Outcomes

    PubMed Central

    Kongnyuy, Michael; George, Arvin K.; Rastinehad, Ardeshir R.; Pinto, Peter A.

    2016-01-01

    Transrectal ultrasound (TRUS)-guided (12–14 core) systematic biopsy of the prostate is the recommended standard for patients with suspicion of prostate cancer (PCa). Advances in imaging have led to the application of magnetic resonance imaging (MRI) for the detection of PCa with subsequent development of software-based co-registration allowing for the integration of MRI with real-time TRUS during prostate biopsy. A number of fusion-guided methods and platforms are now commercially available with common elements in image and analysis and planning. Implementation of fusion-guided prostate biopsy has now been proven to improve the detection of clinically significant PCa in appropriately selected patients. PMID:26902626

  2. MR cone-beam CT fusion image overlay for fluoroscopically guided percutaneous biopsies in pediatric patients.

    PubMed

    Thakor, Avnesh S; Patel, Premal A; Gu, Richard; Rea, Vanessa; Amaral, Joao; Connolly, Bairbre L

    2016-03-01

    Lesions only visible on magnetic resonance (MR) imaging cannot easily be targeted for image-guided biopsy using ultrasound or X-rays but instead require MR guidance with MR-compatible needles and long procedure times (acquisition of multiple MR sequences). We developed an alternative method for performing these difficult biopsies in a standard interventional suite, by fusing MR with cone-beam CT images. The MR cone-beam CT fusion image is then used as an overlay to guide a biopsy needle to the target area under live fluoroscopic guidance. Advantages of this technique include (i) the ability for it to be performed in a conventional interventional suite, (ii) three-dimensional planning of the needle trajectory using cross-sectional imaging, (iii) real-time fluoroscopic guidance for needle trajectory correction and (iv) targeting within heterogeneous lesions based on MR signal characteristics to maximize the potential biopsy yield.

  3. Live imaging using adaptive optics with fluorescent protein guide-stars

    PubMed Central

    Tao, Xiaodong; Crest, Justin; Kotadia, Shaila; Azucena, Oscar; Chen, Diana C.; Sullivan, William; Kubby, Joel

    2012-01-01

    Spatially and temporally dependent optical aberrations induced by the inhomogeneous refractive index of live samples limit the resolution of live dynamic imaging. We introduce an adaptive optical microscope with a direct wavefront sensing method using a Shack-Hartmann wavefront sensor and fluorescent protein guide-stars for live imaging. The results of imaging Drosophila embryos demonstrate its ability to correct aberrations and achieve near diffraction limited images of medial sections of large Drosophila embryos. GFP-polo labeled centrosomes can be observed clearly after correction but cannot be observed before correction. Four dimensional time lapse images are achieved with the correction of dynamic aberrations. These studies also demonstrate that the GFP-tagged centrosome proteins, Polo and Cnn, serve as excellent biological guide-stars for adaptive optics based microscopy. PMID:22772285

  4. Multiobjective guided priors improve the accuracy of near-infrared spectral tomography for breast imaging

    NASA Astrophysics Data System (ADS)

    Feng, Jinchao; Jiang, Shudong; Xu, Junqing; Zhao, Yan; Pogue, Brian W.; Paulsen, Keith D.

    2016-09-01

    An image reconstruction regularization approach for magnetic resonance imaging-guided near-infrared spectral tomography has been developed to improve quantification of total hemoglobin (HbT) and water. By combining prior information from dynamic contrast enhanced (DCE) and diffusion weighted (DW) MR images, the absolute bias errors of HbT and water in the tumor were reduced by 22% and 18%, 21% and 6%, and 10% and 11%, compared to that in the no-prior, DCE- or DW-guided reconstructed images in three-dimensional simulations, respectively. In addition, the apparent contrast values of HbT and water were increased in patient image reconstruction from 1.4 and 1.4 (DCE) or 1.8 and 1.4 (DW) to 4.6 and 1.6.

  5. Kinematical properties of migrated images: A guide for prestack interpretation

    SciTech Connect

    Apostoiu-Marin, I.; Ehinger, A.; Lailly, P.

    1994-12-31

    Migration velocity analysis (van Trier, 1990, Grau and Lailly, 1993, Stork, 1992) is an approach dedicated to imaging of complex geological structures. This analysis requires interpretation of individual migrated images that have been obtained using a probably erroneous velocity model of the subsurface. Thus, the images do not show the correct shape of the geological structures and, moreover, the reflector geometries can change drastically from one image to another. Thus, geological knowledge is only of very limited help for interpretation of individual migrated images obtained with erroneous velocity models. The authors propose a solution to overcome this difficulty in the context of shot record migration. This solution is based on image-theoretical considerations which complement geological ones and thus make interpretation possible. The image-theoretical concepts for interpretation can be obtained from a high frequency (asymptotic) description of seismic modeling and migration. Although the results obtained with this theory are classical, they have never been practically employed for interpretation. In this paper, the authors recall these theoretical results, present them from the viewpoint of interpretation and apply them to a synthetic data example.

  6. Patient-specific Deformation Modelling via Elastography: Application to Image-guided Prostate Interventions

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Ni, Dong; Qin, Jing; Xu, Ming; Xie, Xiaoyan; Heng, Pheng-Ann

    2016-06-01

    Image-guided prostate interventions often require the registration of preoperative magnetic resonance (MR) images to real-time transrectal ultrasound (TRUS) images to provide high-quality guidance. One of the main challenges for registering MR images to TRUS images is how to estimate the TRUS-probe-induced prostate deformation that occurs during TRUS imaging. The combined statistical and biomechanical modeling approach shows promise for the adequate estimation of prostate deformation. However, the right setting of the biomechanical parameters is very crucial for realistic deformation modeling. We propose a patient-specific deformation model equipped with personalized biomechanical parameters obtained from shear wave elastography to reliably predict the prostate deformation during image-guided interventions. Using data acquired from a prostate phantom and twelve patients with suspected prostate cancer, we compared the prostate deformation model with and without patient-specific biomechanical parameters in terms of deformation estimation accuracy. The results show that the patient-specific deformation model possesses favorable model ability, and outperforms the model without patient-specific biomechanical parameters. The employment of the patient-specific biomechanical parameters obtained from elastography for deformation modeling shows promise for providing more precise deformation estimation in applications that use computer-assisted image-guided intervention systems.

  7. Patient-specific Deformation Modelling via Elastography: Application to Image-guided Prostate Interventions

    PubMed Central

    Wang, Yi; Ni, Dong; Qin, Jing; Xu, Ming; Xie, Xiaoyan; Heng, Pheng-Ann

    2016-01-01

    Image-guided prostate interventions often require the registration of preoperative magnetic resonance (MR) images to real-time transrectal ultrasound (TRUS) images to provide high-quality guidance. One of the main challenges for registering MR images to TRUS images is how to estimate the TRUS-probe-induced prostate deformation that occurs during TRUS imaging. The combined statistical and biomechanical modeling approach shows promise for the adequate estimation of prostate deformation. However, the right setting of the biomechanical parameters is very crucial for realistic deformation modeling. We propose a patient-specific deformation model equipped with personalized biomechanical parameters obtained from shear wave elastography to reliably predict the prostate deformation during image-guided interventions. Using data acquired from a prostate phantom and twelve patients with suspected prostate cancer, we compared the prostate deformation model with and without patient-specific biomechanical parameters in terms of deformation estimation accuracy. The results show that the patient-specific deformation model possesses favorable model ability, and outperforms the model without patient-specific biomechanical parameters. The employment of the patient-specific biomechanical parameters obtained from elastography for deformation modeling shows promise for providing more precise deformation estimation in applications that use computer-assisted image-guided intervention systems. PMID:27272239

  8. Monte Carlo feasibility study for image guided surgery: from direct beta minus detection to Cerenkov luminescence imaging

    NASA Astrophysics Data System (ADS)

    Gigliotti, C. R.; Altabella, L.; Boschi, F.; Spinelli, A. E.

    2016-07-01

    The goal of this work is to compare the performances of different beta minus detection strategies for image guided surgery or ex vivo tissue analysis. In particular we investigated Cerenkov luminescence imaging (CLI) with and without the use of a radiator, direct and indirect beta detection and bremsstrahlung imaging using beta emitters commonly employed in Nuclear Medicine. Monte Carlo simulations were implemented using the GAMOS plug-in for GEANT4 considering a slab of muscle and a radioactive source (32P or 90Y) placed at 0.5 mm depth. We estimated the gain that can be obtained in terms of produced photons using different materials placed on the slab used as Cerenkov radiators, we then focused on the number of exiting photons and their spatial distribution for the different strategies. The use of radiator to enhance Cerenkov signal reduces the spatial resolution because of the increased optical spread. We found that direct beta detection and CLI are best approaches in term of resolution while the use of a thin scintillator increases the signal but the spatial resolution is degraded. Bremsstrahlung presents lower signal and it does not represent the best choice for image guided surgery. CLI represents a more flexible approach for image guided surgery using or ex vivo tissue analysis using beta-emitter imaging.

  9. Image guided surgery in the management of craniocerebral gunshot injuries

    PubMed Central

    Elserry, Tarek; Anwer, Hesham; Esene, Ignatius Ngene

    2013-01-01

    Background: A craniocerebral trauma caused by firearms is a complex injury with high morbidity and mortality. One of the most intriguing and controversial part in their management in salvageable patients is the decision to remove the bullet/pellet. A bullet is foreign to the brain and, in principle, should be removed. Surgical options for bullet extraction span from conventional craniotomy, through C-arm-guided surgery to minimally invasive frame or frameless stereotaxy. But what is the best surgical option? Methods: We prospectively followed up a cohort of 28 patients with cranio-cerebral gunshot injury (CCHSI) managed from January to December 2012 in our department of neurosurgery. The missiles were extracted via stereotaxy (frame or frameless), C-arm-guided, or free-hand-based surgery. Cases managed conservatively were excluded. The Glasgow Outcome Score was used to assess the functional outcome on discharge. Results: Five of the eight “stereotactic cases” had an excellent outcome after missile extraction while the initially planned stereotaxy missed locating the missile in three cases and were thus subjected to free hand craniotomy. Excellent outcome was obtained in five of the nine “neuronavigation cases, five of the eight cases for free hand surgery based on the bony landmarks, and five of the six C-arm-based surgery. Conclusion: Conventional craniotomy isn’t indicated in the extraction of isolated, retained, intracranial firearm missiles in civilian injury but could be useful when the missile is incorporated within a surgical lesion. Stereotactic surgery could be useful for bullet extraction, though with limited precision in identifying small pellets because of their small sizes, thus exposing patients to same risk of brain insult when retrieving a missile by conventional surgery. Because of its availability, C-arm-guided surgery continues to be of much benefit, especially in emergency situations. We recommend an extensive long-term study of these

  10. Image-Guided Endoscopic Endonasal Transmaxillary Transpterygoid Approach to Meckel's Cave.

    PubMed

    Wang, Xuejian; Zhang, Xiaobiao; Hu, Fan; Yu, Yong; Gu, Ye; Xie, Tao; Ge, Junqi

    2016-01-01

    The aim of this report was to summarize our preliminary experience on the resection of tumors located in Meckel's cave via the endoscopic endonasal transmaxillary transpterygoid approach with image-guided system and to investigate the feasibility and efficacy of this approach. Two patients who had tumors in left Meckel's cave underwent surgical treatment using the image-guided endoscopic endonasal transmaxillary transpterygoid approach. This particular technique has advantages of no brain retraction, direct vision of tumor resection and protection of surrounding neurovascular structures. Neuronavigation increases the safety of the endoscopic approach.

  11. Autonomic neurosurgery: from microvascular decompression to image guided stimulation

    PubMed Central

    Pereira, EAC; Green, AL

    2007-01-01

    The paper reviews mechanisms underlying autonomic disorders, with a focus on cardiovascular dysfunction. Neurosurgical approaches are described for medically refractory hypertension and orthostatic hypotension. After review of microvascular decompression of the rostral ventrolateral medulla, stereotactic CT and MRI guided deep brain stimulation of the periaqueductal grey matter (PAG) is evaluated. Results are presented from patient studies showing reductions in blood pressure with ventral PAG stimulation and increases in blood pressure with dorsal PAG stimulation. A rationale for the treatment of autonomic disorders by neurosurgical intervention is discussed. PMID:21614256

  12. Subject-specific models for image-guided cardiac surgery

    NASA Astrophysics Data System (ADS)

    Wierzbicki, Marcin; Moore, John; Drangova, Maria; Peters, Terry

    2008-10-01

    Three-dimensional visualization for planning and guidance is still not routinely available for minimally invasive cardiac surgery (MICS). This can be addressed by providing the surgeon with subject-specific geometric models derived from 3D preoperative images for planning of port locations or to rehearse the procedure. For guidance purposes, these models can also be registered to the subject using intraoperative images. In this paper, we present a method for extracting subject-specific heart geometry from preoperative MR images. The main obstacle we face is the low quality of clinical data in terms of resolution, signal-to-noise ratio, and presence of artefacts. Instead of using these images directly, we approach the problem in three steps: (1) generate a high quality template model, (2) register the template with the preoperative data, and (3) animate the result over the cardiac cycle. Validation of this approach showed that dynamic subject-specific models can be generated with a mean error of 3.6 ± 1.1 mm from low resolution target images (6 mm slices). Thus, the models are sufficiently accurate for MICS training and procedure planning. In terms of guidance, we also demonstrate how the resulting models may be adapted to the operating room using intraoperative ultrasound imaging.

  13. Image-guided Raman spectroscopic recovery of canine cortical bone contrast in situ

    PubMed Central

    Srinivasan, Subhadra; Schulmerich, Matthew; Cole, Jacqueline H.; Dooley, Kathryn A.; Kreider, Jaclynn M.; Pogue, Brian W.; Morris, Michael D.; Goldstein, Steven A.

    2009-01-01

    Raman scattering provides valuable biochemical and molecular markers for studying bone tissue composition with use in predicting fracture risk in osteoporosis. Raman tomography can image through a few centimeters of tissue but is limited by low spatial resolution. X-ray computed tomography (CT) imaging can provide high-resolution image-guidance of the Raman spectroscopic characterization, which enhances the quantitative recovery of the Raman signals, and this technique provides additional information to standard imaging methods. This hypothesis was tested in data measured from Teflon® tissue phantoms and from a canine limb. Image-guided Raman spectroscopy (IG-RS) of the canine limb using CT images of the tissue to guide the recovery recovered a contrast of 145:1 between the cortical bone and background. Considerably less contrast was found without the CT image to guide recovery. This study presents the first known IG-RS results from tissue and indicates that intrinsically high contrasts (on the order of a hundred fold) are available. PMID:18679495

  14. FluoSTIC: miniaturized fluorescence image-guided surgery system

    NASA Astrophysics Data System (ADS)

    Gioux, Sylvain; Coutard, Jean-Guillaume; Berger, Michel; Grateau, Henri; Josserand, Véronique; Keramidas, Michelle; Righini, Christian; Coll, Jean-Luc; Dinten, Jean-Marc

    2012-10-01

    Over the last few years, near-infrared (NIR) fluorescence imaging has witnessed rapid growth and is already used in clinical trials for various procedures. However, most clinically compatible imaging systems are optimized for large, open-surgery procedures. Such systems cannot be employed during head and neck oncologic surgeries because the system is not able to image inside deep cavities or allow the surgeon access to certain tumors due to the large footprint of the system. We describe a miniaturized, low-cost, NIR fluorescence system optimized for clinical use during oral oncologic surgeries. The system, termed FluoSTIC, employs a miniature, high-quality, consumer-grade lipstick camera for collecting fluorescence light and a novel custom circular optical fiber array for illumination that combines both white light and NIR excitation. FluoSTIC maintains fluorescence imaging quality similar to that of current large-size imaging systems and is 22 mm in diameter and 200 mm in height and weighs less than 200 g.

  15. 3-D Image-guided diffuse optical tomography using boundary element method and MPI implementation.

    PubMed

    Srinivasan, Subhadra; Ghadyani, Hamid

    2011-01-01

    Boundary elements provide an attractive method for image-guided multi-modality near infrared spectroscopy in three dimensions using only surface discretization. This method operates under the assumption that the underlying tissue contains piece-wise constant domains whose boundaries are known a priori from an alternative imaging modality such as MRI or microCT. This significantly simplifies the meshing process providing both speed-up and accuracy in the forward solution. Challenges with this method are in solving dense matrices, and working with complex heterogeneous domains. Solutions to these problems are presented here, with applications in breast cancer imaging and small - animal molecular imaging.

  16. Image-guided cancer surgery using near-infrared fluorescence

    PubMed Central

    Vahrmeijer, Alexander L.; Hutteman, Merlijn; van der Vorst, Joost R.; van de Velde, C.J.H.; Frangioni, John V.

    2013-01-01

    Paradigm shifts in surgery arise when surgeons are empowered to perform surgery faster, better, and/or less expensively. Optical imaging that exploits invisible near-infrared fluorescent light has the potential to improve cancer surgery outcomes while minimizing anesthesia time and lowering healthcare costs. Because of this, the last few years have witnessed an explosion of proof-of-concept clinical trials in the field. In this review, we introduce the concept of near-infrared fluorescence imaging for cancer surgery, review the clinical trial literature to date, outline the key issues pertaining to imaging system and contrast agent optimization, discuss limitations and leverage, and provide a framework for making the technology available for the routine care of cancer patients in the near future. PMID:23881033

  17. Trends in Fluorescence Image-guided Surgery for Gliomas

    PubMed Central

    Liu, Jonathan T.C.; Meza, Daphne; Sanai, Nader

    2014-01-01

    Mounting evidence suggests that a more extensive surgical resection is associated with an improved life expectancy for both low-grade and high-grade glioma patients. However, radiographically complete resections are not often achieved in many cases due to the lack of sensitivity and specificity of current neurosurgical guidance techniques at the margins of diffuse infiltrative gliomas. Intraoperative fluorescence imaging offers the potential to improve the extent of resection and to investigate the possible benefits of resecting beyond the radiographic margins. Here, we provide a review of wide-field and high-resolution fluorescence-imaging strategies that are being developed for neurosurgical guidance, with a focus on emerging imaging technologies and clinically viable contrast agents. The strengths and weaknesses of these approaches will be discussed, as well as issues that are being addressed to translate these technologies into the standard of care. PMID:24618801

  18. Radio-optical reference frame link using the U.S. Naval observatory astrograph and deep CCD imaging

    SciTech Connect

    Zacharias, N.; Zacharias, M. I.

    2014-05-01

    Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3σ level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.

  19. Imaging-guided hyperstimulation analgesia in low back pain

    PubMed Central

    Gorenberg, Miguel; Schwartz, Kobi

    2013-01-01

    Low back pain in patients with myofascial pain syndrome is characterized by painful active myofascial trigger points (ATPs) in muscles. This article reviews a novel, noninvasive modality that combines simultaneous imaging and treatment, thus taking advantage of the electrodermal information available from imaged ATPs to deliver localized neurostimulation, to stimulate peripheral nerve endings (Aδ fibers) and in turn, to release endogenous endorphins. “Hyperstimulation analgesia” with localized, intense, low-rate electrical pulses applied to painful ATPs was found to be effective in 95% patients with chronic nonspecific low back pain, in a clinical validation study. PMID:23847430

  20. High-Intensity Focused Ultrasound: Current Status for Image-Guided Therapy

    PubMed Central

    Copelan, Alexander; Hartman, Jason; Chehab, Monzer; Venkatesan, Aradhana M.

    2015-01-01

    Image-guided high-intensity focused ultrasound (HIFU) is an innovative therapeutic technology, permitting extracorporeal or endocavitary delivery of targeted thermal ablation while minimizing injury to the surrounding structures. While ultrasound-guided HIFU was the original image-guided system, MR-guided HIFU has many inherent advantages, including superior depiction of anatomic detail and superb real-time thermometry during thermoablation sessions, and it has recently demonstrated promising results in the treatment of both benign and malignant tumors. HIFU has been employed in the management of prostate cancer, hepatocellular carcinoma, uterine leiomyomas, and breast tumors, and has been associated with success in limited studies for palliative pain management in pancreatic cancer and bone tumors. Nonthermal HIFU bioeffects, including immune system modulation and targeted drug/gene therapy, are currently being explored in the preclinical realm, with an emphasis on leveraging these therapeutic effects in the care of the oncology patient. Although still in its early stages, the wide spectrum of therapeutic capabilities of HIFU offers great potential in the field of image-guided oncologic therapy. PMID:26622104

  1. A miniaturized imaging system for optical guided surgery of head and neck cancer

    NASA Astrophysics Data System (ADS)

    Atallah, Ihab; Milet, Clément; Dorval, Paul; Gayet, Pascal; Rizo, Philippe; Henry, Maxime; Reyt, Emile; Josserand, Véronique; Hurbin, Amandine; Righini, Christian; Coll, Jean-Luc

    2015-03-01

    Near-infrared fluorescence image-guided surgery, FIGS, has lately shown a huge potential in oncologic and lymphatic related surgeries. In some indications such as liver or heart surgery, fluorescence-reachable anatomic structures are limited by the access to the surgical field. Nevertheless, most of the systems available on the market are too large to image the sides of cavities. Small devices are clearly required to improve workability of fluorescence imaging systems. The current work describes the evaluation of Fluostick a CE med certified instrument dedicated to narrow area imaging. This small size device is made of an optical head connected to a control box. We tested this instrumentation at the preclinical level for the optical-guided surgery of head and neck tumors.

  2. [Medical image segmentation based on guided filtering and multi-atlas].

    PubMed

    Wen, Rui; Chen, Hongwen; Zhang, Lei; Lu, Zhentai

    2015-08-01

    A novel medical automatic image segmentation strategy based on guided filtering and multi-atlas is proposed to achieve accurate, smooth, robust, and reliable segmentation. This framework consists of 4 elements: the multi-atlas registration, which uses the atlas prior information; the label fusion, in which the similarity measure of the registration is used as the weight to fuse the warped label; the guided filtering, which uses the local information of the target image to correct the registration errors; and the threshold approaches used to obtain the segment result. The experimental results showed part among the 15 brain MRI images used to segment the hippocampus region, the proposed method achieved a median Dice coefficient of 86% on the left hippocampus and 87.4% on the right hippocampus. Compared with the traditional label fusion algorithm, the proposed algorithm outperforms the common brain image segmentation methods with a good efficiency and accuracy.

  3. Image-guided techniques for localizing pulmonary nodules in thoracoscopic surgery

    PubMed Central

    Lin, Mong-Wei

    2016-01-01

    Low-dose computed tomography (LDCT) screening has increased the detection rate for small pulmonary nodules with ground-glass opacity (GGO) in the peripheral lung parenchyma. Minimally invasive thoracoscopic surgery for these lung nodules is challenging for thoracic surgeons, and image-guided preoperative localization is mandatory for their successful resection. Image-guided localization methods primarily include two imaging tools: computed tomography (CT) and bronchoscopy. These different methods may use different localized materials, including hookwires, dyes, microcoils, fiducial markers, contrast media, and radiotracers. Ultrasonography and near-infrared imaging are also used for intraoperative localization of lung lesions. In this article, we review different localization techniques and discuss their indications and limitations. PMID:28066679

  4. Radio-Tomographic Images of Post-midnight Equatorial Plasma Depletions

    NASA Astrophysics Data System (ADS)

    Hei, M. A.; Bernhardt, P. A.; Siefring, C. L.; Wilkens, M.; Huba, J. D.; Krall, J.; Valladares, C. E.; Heelis, R. A.; Hairston, M. R.; Coley, W. R.; Chau, J. L.

    2013-12-01

    For the first time, post-midnight equatorial plasma depletions (EPDs) have been imaged in the longitude-altitude plane using radio-tomography. High-resolution (~10 km × 10 km) electron-density reconstructions were created from total electron content (TEC) data using an array of receivers sited in Peru and the Multiplicative Algebraic Reconstruction Technique (MART) inversion algorithm. TEC data were obtained from the 150 and 400 MHz signals transmitted by the CERTO beacon on the C/NOFS satellite. In-situ electron density data from the C/NOFS CINDI instrument and electron density profiles from the UML Jicamarca ionosonde were used to generate an initial guess for the MART inversion, and also to constrain the inversion process. Observed EPDs had widths of 100-1000 km, spacings of 300-900 km, and often appeared 'pinched off' at the bottom. Well-developed EPDs appeared on an evening with a very small (4 m/s) Pre-Reversal-Enhancement (PRE), suggesting that postmidnight enhancements of the vertical plasma drift and/or seeding-induced uplifts (e.g. gravity waves) were responsible for driving the Rayleigh-Taylor Instability into the nonlinear regime on this night. On another night the Jicamarca ISR recorded postmidnight (~0230 LT) Eastward electric fields nearly twice as strong as the PRE fields seven hours earlier. These electric fields lifted the whole ionosphere, including embedded EPDs, over a longitude range ~14° wide. CINDI detected a dawn depletion in exactly the area where the reconstruction showed an uplifted EPD. Strong Equatorial Spread-F observed by the Jicamarca ionosonde during receiver observation times confirmed the presence of ionospheric irregularities.

  5. Feature identification for image-guided transcatheter aortic valve implantation

    NASA Astrophysics Data System (ADS)

    Lang, Pencilla; Rajchl, Martin; McLeod, A. Jonathan; Chu, Michael W.; Peters, Terry M.

    2012-02-01

    Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to open-heart surgery, and is critically dependent on imaging for accurate placement of the new valve. Augmented image-guidance for TAVI can be provided by registering together intra-operative transesophageal echo (TEE) ultrasound and a model derived from pre-operative CT. Automatic contour delineation on TEE images of the aortic root is required for real-time registration. This study develops an algorithm to automatically extract contours on simultaneous cross-plane short-axis and long-axis (XPlane) TEE views, and register these features to a 3D pre-operative model. A continuous max-flow approach is used to segment the aortic root, followed by analysis of curvature to select appropriate contours for use in registration. Results demonstrate a mean contour boundary distance error of 1.3 and 2.8mm for the short and long-axis views respectively, and a mean target registration error of 5.9mm. Real-time image guidance has the potential to increase accuracy and reduce complications in TAVI.

  6. MRI-guided brain PET image filtering and partial volume correction.

    PubMed

    Yan, Jianhua; Lim, Jason Chu-Shern; Townsend, David W

    2015-02-07

    Positron emission tomography (PET) image quantification is a challenging problem due to limited spatial resolution of acquired data and the resulting partial volume effects (PVE), which depend on the size of the structure studied in relation to the spatial resolution and which may lead to over or underestimation of the true tissue tracer concentration. In addition, it is usually necessary to perform image smoothing either during image reconstruction or afterwards to achieve a reasonable signal-to-noise ratio. Typically, an isotropic Gaussian filtering (GF) is used for this purpose. However, the noise suppression is at the cost of deteriorating spatial resolution. As hybrid imaging devices such as PET/MRI have become available, the complementary information derived from high definition morphologic images could be used to improve the quality of PET images. In this study, first of all, we propose an MRI-guided PET filtering method by adapting a recently proposed local linear model and then incorporate PVE into the model to get a new partial volume correction (PVC) method without parcellation of MRI. In addition, both the new filtering and PVC are voxel-wise non-iterative methods. The performance of the proposed methods were investigated with simulated dynamic FDG brain dataset and (18)F-FDG brain data of a cervical cancer patient acquired with a simultaneous hybrid PET/MR scanner. The initial simulation results demonstrated that MRI-guided PET image filtering can produce less noisy images than traditional GF and bias and coefficient of variation can be further reduced by MRI-guided PET PVC. Moreover, structures can be much better delineated in MRI-guided PET PVC for real brain data.

  7. MRI-guided brain PET image filtering and partial volume correction

    NASA Astrophysics Data System (ADS)

    Yan, Jianhua; Chu-Shern Lim, Jason; Townsend, David W.

    2015-02-01

    Positron emission tomography (PET) image quantification is a challenging problem due to limited spatial resolution of acquired data and the resulting partial volume effects (PVE), which depend on the size of the structure studied in relation to the spatial resolution and which may lead to over or underestimation of the true tissue tracer concentration. In addition, it is usually necessary to perform image smoothing either during image reconstruction or afterwards to achieve a reasonable signal-to-noise ratio. Typically, an isotropic Gaussian filtering (GF) is used for this purpose. However, the noise suppression is at the cost of deteriorating spatial resolution. As hybrid imaging devices such as PET/MRI have become available, the complementary information derived from high definition morphologic images could be used to improve the quality of PET images. In this study, first of all, we propose an MRI-guided PET filtering method by adapting a recently proposed local linear model and then incorporate PVE into the model to get a new partial volume correction (PVC) method without parcellation of MRI. In addition, both the new filtering and PVC are voxel-wise non-iterative methods. The performance of the proposed methods were investigated with simulated dynamic FDG brain dataset and 18F-FDG brain data of a cervical cancer patient acquired with a simultaneous hybrid PET/MR scanner. The initial simulation results demonstrated that MRI-guided PET image filtering can produce less noisy images than traditional GF and bias and coefficient of variation can be further reduced by MRI-guided PET PVC. Moreover, structures can be much better delineated in MRI-guided PET PVC for real brain data.

  8. Image-guided therapies in the treatment of hepatocellular carcinoma: A multidisciplinary perspective.

    PubMed

    Willatt, Jonathon; Hannawa, Kevin K; Ruma, Julie A; Frankel, Timothy L; Owen, Dawn; Barman, Pranab M

    2015-02-27

    A multidisciplinary approach to the treatment of patients with unresectable hepatocellular carcinoma (HCC) has led to improvements in screening, detection, and treatments. Interventional techniques include thermal ablation, transarterial chemoembolization, and radioembolization whilst stereotactic body radiation therapy also uses imaging to target the radiation. Both survival rates and cure rates have improved markedly since the introduction of these techniques. This review article describes the image guided techniques used for the treatment of HCC.

  9. Tailored sinc pulses for uniform excitation and artifact-free radio frequency time-domain EPR imaging.

    PubMed

    Devasahayam, N; Murugesan, R; Matsumoto, K; Mitchell, J B; Cook, J A; Subramanian, S; Krishna, M C

    2004-05-01

    A method to generate shaped radiofrequency pulses for uniform excitation of electron spins in time-domain radio frequency (RF) electron paramagnetic resonance (EPR) imaging is presented. A commercial waveform generator was integrated with the transmit arm of the existing time-domain RF-EPR spectrometer to generate tailored excitation pulses with sub-nano second resolution for excitation with a 90 degrees flip-angle. A truncated sinc [sin(x)/x] pulse, tailored to compensate for the Q-profile (RF frequency response) of the resonator, was shown to yield images from phantom objects as well as in vivo images, with minimal distortion. These studies point to the advantages in using shaped sinc pulses to achieve improved uniform excitation over a relatively wide bandwidth region in time-domain RF-EPR imaging (RF-FT-EPRI).

  10. Magnetic resonance imaging-guided brachytherapy for cervical cancer: initiating a program

    PubMed Central

    Prisciandaro, Joann I.; Soliman, Abraam; Ravi, Ananth; Song, William Y.

    2015-01-01

    Over the past decade, the application of magnetic resonance imaging (MRI) has increased, and there is growing evidence to suggest that improvements in accuracy of target delineation in MRI-guided brachytherapy may improve clinical outcomes in cervical cancer. To implement a high quality image guided brachytherapy program, a multidisciplinary team is required with appropriate expertise as well as an adequate patient load to ensure a sustainable program. It is imperative to know that the most important source of uncertainty in the treatment process is related to target delineation and therefore, the necessity of training and expertise as well as quality assurance should be emphasized. A short review of concepts and techniques that have been developed for implementation and/or improvement of workflow of a MRI-guided brachytherapy program are provided in this document, so that institutions can use and optimize some of them based on their resources to minimize their procedure times. PMID:26622249

  11. Near-infrared image-guided laser ablation of dental decay

    NASA Astrophysics Data System (ADS)

    Tao, You-Chen; Fried, Daniel

    2009-09-01

    Image-guided laser ablation systems are now feasible for dentistry with the recent development of nondestructive high-contrast imaging modalities such as near-IR (NIR) imaging and optical coherence tomography (OCT) that are capable of discriminating between sound and demineralized dental enamel at the early stages of development. Our objective is to demonstrate that images of demineralized tooth surfaces have sufficient contrast to be used to guide a CO2 laser for the selective removal of natural and artificial caries lesions. NIR imaging and polarization-sensitive optical coherence tomography (PS-OCT) operating at 1310-nm are used to acquire images of natural lesions on extracted human teeth and highly patterned artificial lesions produced on bovine enamel. NIR and PS-OCT images are analyzed and converted to binary maps designating the areas on the samples to be removed by a CO2 laser to selectively remove the lesions. Postablation NIR and PS-OCT images confirmed preferential removal of demineralized areas with minimal damage to sound enamel areas. These promising results suggest that NIR and PS-OCT imaging systems can be integrated with a CO2 laser ablation system for the selective removal of dental caries.

  12. Accurate calibration of a stereo-vision system in image-guided radiotherapy

    SciTech Connect

    Liu Dezhi; Li Shidong

    2006-11-15

    Image-guided radiotherapy using a three-dimensional (3D) camera as the on-board surface imaging system requires precise and accurate registration of the 3D surface images in the treatment machine coordinate system. Two simple calibration methods, an analytical solution as three-point matching and a least-squares estimation method as multipoint registration, were introduced to correlate the stereo-vision surface imaging frame with the machine coordinate system. Both types of calibrations utilized 3D surface images of a calibration template placed on the top of the treatment couch. Image transformational parameters were derived from corresponding 3D marked points on the surface images to their given coordinates in the treatment room coordinate system. Our experimental results demonstrated that both methods had provided the desired calibration accuracy of 0.5 mm. The multipoint registration method is more robust particularly for noisy 3D surface images. Both calibration methods have been used as our weekly QA tools for a 3D image-guided radiotherapy system.

  13. Optimization of Focused Ultrasound and Image Based Modeling in Image Guided Interventions

    NASA Astrophysics Data System (ADS)

    Almekkawy, Mohamed Khaled Ibrahim

    Image-guided high intensity focused ultrasound (HIFU) is becoming increasingly accepted as a form of noninvasive ablative therapy for the treatment of prostate cancer, uterine fibroids and other tissue abnormalities. In principle, HIFU beams can be focused within small volumes which results in forming precise lesions within the target volume (e.g. tumor, atherosclerotic plaque) while sparing the intervening tissue. With this precision, HIFU offers the promise of noninvasive tumor therapy. The goal of this thesis is to develop an image-guidance mode with an interactive image-based computational modeling of tissue response to HIFU. This model could be used in treatment planning and post-treatment retrospective evaluation of treatment outcome(s). Within the context of treatment planning, the challenge of using HIFU to target tumors in organs partially obscured by the rib cage are addressed. Ribs distort HIFU beams in a manner that reduces the focusing gain at the target (tumor) and could cause a treatment-limiting collateral damage. We present a refocusing algorithms to efficiently steer higher power towards the target while limiting power deposition on the ribs, improving the safety and efficacy of tumor ablation. Our approach is based on an approximation of a non-convex to a convex optimization known as the semidefinite relaxation (SDR) technique. An important advantage of the SDR method over previously proposed optimization methods is the explicit control of the sidelobes in the focal plane. A finite-difference time domain (FDTD) heterogeneous propagation model of a 1-MHz concave phased array was used to model the acoustic propagation and temperature simulations in different tissues including ribs. The numerical methods developed for the refocusing problem are also used for retrospective analysis of targeting of atherosclerotic plaques using HIFU. Cases were simulated where seven adjacent HIFU shots (5000 W/cm2, 2 sec exposure time) were focused at the plaque

  14. Electron density and temperature in the solar corona from multifrequency radio imaging

    NASA Astrophysics Data System (ADS)

    Mercier, C.; Chambe, G.

    2015-11-01

    Context. The 2D images obtained through rotational aperture synthesis with the Nançay Radioheliograph are suitable for quantitative exploitation. First results are presented. Aims: We study the variations of the quiet corona in brightness and size during an 8-year period and derive electron density and temperature in the corona. Methods: Images at 6 frequencies between 150 and 450 MHz for 183 quiet days between 2004 and 2011 were used. Measurements of the brightness temperature Tb beyond the limb allowed coronal density models to be derived in both EW and NS radial directions, with a weak dependence on the electron temperature. The total ranges in the heliocentric distance r are 1.15-1.60 R⊙ (EW) and 1.0-1.4 R⊙ (NS). The agreement between results from different frequencies, in the ranges of r where there is overlapping shows the robustness of the method. The electron temperature, in turn, can be derived from the comparison of the observed mean spectra on the disk with those predicted through transfer calculations from the density models derived from limb observations. Results: The widths of the brightness profiles that were averaged yearly have minima at cycle minimum (2008-2009). These minima are more pronounced for EW profiles than for NS ones. The derived yearly-averaged density models along equatorial and polar diameters are consistent with isothermal and hydrostatic models. They are characterized by their density value n0 extrapolated down to the base of the corona and their scale-height temperature TH. Changes in n0 and TH with solar cycle are given for equatorial and polar regions. The kinetic temperature Te of electrons in the corona (~0.62 MK) is found to be significantly less than TH (~1.5 MK). This implies an ion temperature Ti ~ 2.2 MK. Conclusions: The yearly-averaged variations of these models are less than the dispersion between models derived from other techniques, such as white light and EUV observations, partly because these two techniques

  15. An audit of pain/discomfort experienced during image-guided breast biopsy procedures.

    PubMed

    Satchithananda, Keshthra; Fernando, Rashika Anne-Marie; Ralleigh, Gita; Evans, David Rohan; Wasan, Rema Kaur; Bose, Shamistha; Donaldson, N; Michell, Michael J

    2005-01-01

    A prospective audit of 221 breast biopsies was carried out to assess the pain/discomfort experienced during image-guided breast biopsies. The only significant factor in pain scores was the size of the needle used. Fine-needle aspiration cytology using a 21-gauge needle was found to cause the most discomfort.

  16. Sclerotic Vertebral Metastases: Pain Palliation Using Percutaneous Image-Guided Cryoablation

    SciTech Connect

    Costa de Freitas, Ricardo Miguel Menezes, Marcos Roberto de; Cerri, Giovanni Guido; Gangi, Afshin

    2011-02-15

    Cryoablative therapies have been proposed to palliate pain from soft-tissue or osteolytic bone tumors. A case of a patient with painful thoracic and sacral spine sclerotic metastases successfully treated by image-guided percutaneous cryoablation with the aid of insulation techniques and thermosensors is reported in this case report.

  17. Assisting in Radiology/Imaging. Instructor's Guide, Student's Manual, and Student Learning Activities.

    ERIC Educational Resources Information Center

    Fair, Helena J.

    The instructor's guide, the first of three documents in this package, is designed for a course to help students who are investigating the activities within a radiology department or considering any of the imaging technologies as a career. The material is designed to relate training experience to information studied in the classroom. This…

  18. Image-guided diagnosis of prostate cancer can increase detection of tumors

    Cancer.gov

    In the largest prospective study to date of image-guided technology for identifying suspicious regions of the prostate to biopsy, researchers compared the ability of this technology to detect high-risk prostate cancer with that of the current standard of

  19. Image-guided elbow interventions: a literature review of interventional treatment options

    PubMed Central

    Sorani, Alan

    2016-01-01

    Over the years, a wide range of image-guided interventional therapies have been used in treating different elbow pathologies, many of which are predominantly based on anecdotal and low-level study findings. This article critically assesses the existing literature and discusses the efficacy of the most commonly utilized interventional procedures for elbow pathology. PMID:26206415

  20. Concurrent Image Processing Executive (CIPE). Volume 3: User's guide

    NASA Technical Reports Server (NTRS)

    Lee, Meemong; Cooper, Gregory T.; Groom, Steven L.; Mazer, Alan S.; Williams, Winifred I.; Kong, Mih-Seh

    1990-01-01

    CIPE (the Concurrent Image Processing Executive) is both an executive which organizes the parameter inputs for hypercube applications and an environment which provides temporary data workspace and simple real-time function definition facilities for image analysis. CIPE provides two types of user interface. The Command Line Interface (CLI) provides a simple command-driven environment allowing interactive function definition and evaluation of algebraic expressions. The menu interface employs a hierarchical screen-oriented menu system where the user is led through a menu tree to any specific application and then given a formatted panel screen for parameter entry. How to initialize the system through the setup function, how to read data into CIPE symbols, how to manipulate and display data through the use of executive functions, and how to run an application in either user interface mode, are described.

  1. Image-guided Control of Flexible Bevel-Tip Needles

    PubMed Central

    Kallem, Vinutha; Cowan, Noah J.

    2010-01-01

    Physicians perform percutaneous therapies in many diagnostic and therapeutic procedures. Image guidance promises to improve targeting accuracy and broaden the scope of needle interventions. In this paper, we consider the possibility of automating the guidance of a flexible bevel-tip needle as it is inserted into human tissue. We build upon a previously proposed nonholonomic kinematic model to develop a nonlinear observer-based controller. As a first step for control, we show that flexible needles can be automatically controlled to remain within a planar slice of tissue as they are inserted by a physician; our approach keeps the physician in the loop to control insertion speed. In the proposed controller, the distance of the needle tip position from the plane of interest is used as a feedback signal. Numerical simulations demonstrate the stability and robustness of the controller in the face of parametric uncertainty. We also present results from pilot physical experiments with phantom tissue under stereo image guidance. PMID:21359170

  2. An image-guided tool to prevent hospital acquired infections

    NASA Astrophysics Data System (ADS)

    Nagy, Melinda; Szilágyi, László; Lehotsky, Ákos; Haidegger, Tamás; Benyó, Balázs

    2011-03-01

    Hospital Acquired Infections (HAI) represent the fourth leading cause of death in the United States, and claims hundreds of thousands of lives annually in the rest of the world. This paper presents a novel low-cost mobile device|called Stery-Hand|that helps to avoid HAI by improving hand hygiene control through providing an objective evaluation of the quality of hand washing. The use of the system is intuitive: having performed hand washing with a soap mixed with UV re ective powder, the skin appears brighter in UV illumination on the disinfected surfaces. Washed hands are inserted into the Stery-Hand box, where a digital image is taken under UV lighting. Automated image processing algorithms are employed in three steps to evaluate the quality of hand washing. First, the contour of the hand is extracted in order to distinguish the hand from the background. Next, a semi-supervised clustering algorithm classies the pixels of the hand into three groups, corresponding to clean, partially clean and dirty areas. The clustering algorithm is derived from the histogram-based quick fuzzy c-means approach, using a priori information extracted from reference images, evaluated by experts. Finally, the identied areas are adjusted to suppress shading eects, and quantied in order to give a verdict on hand disinfection quality. The proposed methodology was validated through tests using hundreds of images recorded in our laboratory. The proposed system was found robust and accurate, producing correct estimation for over 98% of the test cases. Stery-Hand may be employed in general practice, and it may also serve educational purposes.

  3. Combination of nonlinear ultrasonics and guided wave tomography for imaging the micro-defects.

    PubMed

    Li, Weibin; Cho, Younho

    2016-02-01

    The use of guided wave tomography has become an attractive alternative to convert ultrasonic wave raw data to visualized results for quantitative signal interpretation. For more accurate life prediction and efficient management strategies for critical structural components, there is a demand of imaging micro-damages in early stage. However, there is rarely investigation on guided wave tomographic imaging of micro-defects. One of the reasons for this might be that it becomes challenging to monitor tiny signal difference coefficient in a reliable manner for wave propagation in the specimens with micro-damages. Nonlinear acoustic signal whose frequency differs from that of the input signal can be found in the specimens with micro-damages. Therefore, the combination of guided wave tomography and nonlinear acoustic response induced by micro-damages could be a feasibility study for imaging micro-damages. In this paper, the nonlinear Rayleigh surface wave tomographic method is investigated to locate and size micro-corrosive defect region in an isotropic solid media. The variations of acoustic nonlinear responses of ultrasonic waves in the specimens with and without defects are used in guided wave tomographic algorithm to construct the images. The comparisons between images obtained by experimental signals and real defect region induced by hydrogen corrosion are presented in this paper. Results show that the images of defect regions with different shape, size and location are successfully obtained by this novel technique, while there is no visualized result constructed by conventional linear ultrasonic tomographic one. The present approach shows a potential for inspecting, locating and imaging micro-defects by nonlinear Rayleigh surface wave tomography.

  4. Image-guided spine surgery: state of the art and future directions

    PubMed Central

    Shafizadeh, Sven; Rixen, Dieter; Paffrath, Thomas; Bouillon, Bertil; Steinhausen, Eva S.; Baethis, Holger

    2009-01-01

    Navigation technology is a widely available tool in spine surgery and has become a part of clinical routine in many centers. The issue of where and when navigation technology should be used is still an issue of debate. It is the aim of this study to give an overview on the current knowledge concerning the technical capabilities of image-guided approaches and to discuss possible future directions of research and implementation of this technique. Based on a Medline search total of 1,462 publications published until October 2008 were retrieved. The abstracts were scanned manually for relevance to the topics of navigated spine surgery in the cervical spine, the thoracic spine, the lumbar spine, as well as ventral spine surgery, radiation exposure, tumor surgery and cost-effectivity in navigated spine surgery. Papers not contributing to these subjects were deleted resulting in 276 papers that were included in the analysis. Image-guided approaches have been investigated and partially implemented into clinical routine in virtually any field of spine surgery. However, the data available is mostly limited to small clinical series, case reports or retrospective studies. Only two RCTs and one metaanalysis have been retrieved. Concerning the most popular application of image-guided approaches, pedicle screw insertion, the evidence of clinical benefit in the most critical areas, e.g. the thoracic spine, is still lacking. In many other areas of spine surgery, e.g. ventral spine surgery or tumor surgery, image-guided approaches are still in an experimental stage. The technical development of image-guided techniques has reached a high level as the accuracies that can be achieved technically meet the anatomical demands. However, there is evidence that the interaction between the surgeon (‘human factor’) and the navigation system is a source of inaccuracy. It is concluded that more effort needs to be spend to understand this interaction. PMID:19763640

  5. Precision-guided surgical navigation system using laser guidance and 3D autostereoscopic image overlay.

    PubMed

    Liao, Hongen; Ishihara, Hirotaka; Tran, Huy Hoang; Masamune, Ken; Sakuma, Ichiro; Dohi, Takeyoshi

    2010-01-01

    This paper describes a precision-guided surgical navigation system for minimally invasive surgery. The system combines a laser guidance technique with a three-dimensional (3D) autostereoscopic image overlay technique. Images of surgical anatomic structures superimposed onto the patient are created by employing an animated imaging method called integral videography (IV), which can display geometrically accurate 3D autostereoscopic images and reproduce motion parallax without the need for special viewing or tracking devices. To improve the placement accuracy of surgical instruments, we integrated an image overlay system with a laser guidance system for alignment of the surgical instrument and better visualization of patient's internal structure. We fabricated a laser guidance device and mounted it on an IV image overlay device. Experimental evaluations showed that the system could guide a linear surgical instrument toward a target with an average error of 2.48 mm and standard deviation of 1.76 mm. Further improvement to the design of the laser guidance device and the patient-image registration procedure of the IV image overlay will make this system practical; its use would increase surgical accuracy and reduce invasiveness.

  6. Image-Guided Surgery using Invisible Near-Infrared Light: Fundamentals of Clinical Translation

    PubMed Central

    Gioux, Sylvain; Choi, Hak Soo; Frangioni, John V.

    2011-01-01

    The field of biomedical optics has matured rapidly over the last decade and is poised to make a significant impact on patient care. In particular, wide-field (typically > 5 cm), planar, near-infrared (NIR) fluorescence imaging has the potential to revolutionize human surgery by providing real-time image guidance to surgeons for tissue that needs to be resected, such as tumors, and tissue that needs to be avoided, such as blood vessels and nerves. However, to become a clinical reality, optimized imaging systems and NIR fluorescent contrast agents will be needed. In this review, we introduce the principles of NIR fluorescence imaging, analyze existing NIR fluorescence imaging systems, and discuss the key parameters that guide contrast agent development. We also introduce the complexities surrounding clinical translation using our experience with the Fluorescence-Assisted Resection and Exploration (FLARE™) imaging system as an example. Finally, we introduce state-of-the-art optical imaging techniques that might someday improve image-guided surgery even further. PMID:20868625

  7. Percutaneous imaging-guided cryoablation for lung cancer

    PubMed Central

    Zhang, Yi-Shi; Niu, Li-Zhi; Zhan, Ke; Li, Zhong-Hai; Huang, Yu-Gang; Yang, Yi; Chen, Ji-Bing

    2016-01-01

    Percutaneous cryoablation under imaging guidance has been proved to be a safe and effective method for ablation and debulking of tumors, providing radical cure or palliation, as the case may be, for patients with different stages of disease. The local control rate is high with cryoablation, and the complications are usually controllable, making it a reasonable choice in lung cancer treatment. In this paper the technique and mechanism of action of cryoablation are summarized, and studies performed on the application of percutaneous cryoablation in various stages of lung cancer are reviewed. Its emerging application in the treatment of pure ground-glass nodules (GGNs) is also introduced. PMID:28066673

  8. Percutaneous imaging-guided cryoablation for lung cancer.

    PubMed

    Zhang, Yi-Shi; Niu, Li-Zhi; Zhan, Ke; Li, Zhong-Hai; Huang, Yu-Gang; Yang, Yi; Chen, Ji-Bing; Xu, Ke-Cheng

    2016-10-01

    Percutaneous cryoablation under imaging guidance has been proved to be a safe and effective method for ablation and debulking of tumors, providing radical cure or palliation, as the case may be, for patients with different stages of disease. The local control rate is high with cryoablation, and the complications are usually controllable, making it a reasonable choice in lung cancer treatment. In this paper the technique and mechanism of action of cryoablation are summarized, and studies performed on the application of percutaneous cryoablation in various stages of lung cancer are reviewed. Its emerging application in the treatment of pure ground-glass nodules (GGNs) is also introduced.

  9. Radio Galaxies.

    ERIC Educational Resources Information Center

    Downes, Ann

    1986-01-01

    Provides background information on radio galaxies. Topic areas addressed include: what produces the radio emission; radio telescopes; locating radio galaxies; how distances to radio galaxies are found; physics of radio galaxies; computer simulations of radio galaxies; and the evolution of radio galaxies with cosmic time. (JN)

  10. MR-Guided Delivery of Hydrophilic Molecular Imaging Agents Across the Blood-Brain Barrier Through Focused Ultrasound

    PubMed Central

    Airan, Raag D.; Foss, Catherine A.; Ellens, Nicholas P. K.; Wang, Yuchuan; Mease, Ronnie C.; Farahani, Keyvan; Pomper, Martin G.

    2016-01-01

    Purpose A wide variety of hydrophilic imaging and therapeutic agents are unable to gain access to the central nervous system (CNS) due to the blood-brain barrier (BBB). In particular, unless a particular transporter exists that may transport the agent across the BBB, most agents that are larger than 500 Da or that are hydrophilic will be excluded by the BBB. Glutamate carboxypeptidase II (GCPII), also known as the prostate-specific membrane antigen (PSMA) in the periphery, has been implicated in various neuropsychiatric conditions. As all agents that target GCPII are hydrophilic and thereby excluded from the CNS, we used GCPII as a platform for demonstrating our MR-guided focused ultrasound (MRgFUS) technique for delivery of GCPII/PSMA-specific imaging agents to the brain. Procedures Female rats underwent MRgFUS-mediated opening of the BBB. After opening of the BBB, either a radio- or fluorescently labeled ureido-based ligand for GCPII/PSMA was administered intravenously. Brain uptake was assessed for 2-(3-{1-carboxy-5-[(6-[18F]fluoropyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid ([18F]DCFPyL) and YC-27, two compounds known to bind GCPII/PSMA with high affinity, using positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging, respectively. Specificity of ligand binding to GCPII/PSMA in the brain was determined with co-administration of a molar excess of ZJ-43, a compound of the same chemical class but different structure from either [18F]DCFPyL or YC-27, which competes for GCPII/PSMA binding. Results Dynamic PET imaging using [18F]DCFPyL demonstrated that target uptake reached a plateau by ~1 h after radiotracer administration, with target/background ratios continuing to increase throughout the course of imaging, from a ratio of ~4:1 at 45 min to ~7:1 by 80 min. NIRF imaging likewise demonstrated delivery of YC-27 to the brain, with clear visualization of tracer in the brain at 24 h. Tissue uptake of both ligands was greatly

  11. Prospective Evaluation of Dual-Energy Imaging in Patients Undergoing Image Guided Radiation Therapy for Lung Cancer: Initial Clinical Results

    SciTech Connect

    Sherertz, Tracy; Hoggarth, Mark; Luce, Jason; Block, Alec M.; Nagda, Suneel; Harkenrider, Matthew M.; Emami, Bahman; Roeske, John C.

    2014-07-01

    Purpose: A prospective feasibility study was conducted to investigate the utility of dual-energy (DE) imaging compared to conventional x-ray imaging for patients undergoing kV-based image guided radiation therapy (IGRT) for lung cancer. Methods and Materials: An institutional review board-approved feasibility study enrolled patients with lung cancer undergoing IGRT and was initiated in September 2011. During daily setup, 2 sequential respiration-gated x-ray images were obtained using an on-board imager. Imaging was composed of 1 standard x-ray image at 120 kVp (1 mAs) and a second image obtained at 60 kVp (4 mAs). Weighted logarithmic subtraction of the 2 images was performed offline to create a soft tissue-selective DE image. Conventional and DE images were evaluated by measuring relative contrast and contrast-to-noise ratios (CNR) and also by comparing spatial localization, using both approaches. Imaging dose was assessed using a calibrated ion chamber. Results: To date, 10 patients with stage IA to IIIA lung cancer were enrolled and 57 DE images were analyzed. DE subtraction resulted in complete suppression of overlying bone in all 57 DE images, with an average improvement in relative contrast of 4.7 ± 3.3 over that of 120 kVp x-ray images (P<.0002). The improvement in relative contrast with DE imaging was seen for both smaller (gross tumor volume [GTV] ≤5 cc) and larger tumors (GTV >5 cc), with average relative contrast improvement ratios of 3.4 ± 4.1 and 5.4 ± 3.6, respectively. Moreover, the GTV was reliably localized in 95% of the DE images versus 74% of the single energy (SE images, (P=.004). Mean skin dose per DE image set was 0.44 ± 0.03 mGy versus 0.43 ± 0.03 mGy, using conventional kV imaging parameters. Conclusions: Initial results of this feasibility study suggest that DE thoracic imaging may enhance tumor localization in lung cancer patients receiving kV-based IGRT without increasing imaging dose.

  12. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    NASA Astrophysics Data System (ADS)

    Kang, Jin U.; Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-08-01

    The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10 volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8 mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed "ultra microvascular" feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter˜0.1 mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment.

  13. Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks.

    PubMed

    Heintz, Keely A; Mayerich, David; Slater, John H

    2017-01-03

    This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic networks embedded in PEGDA hydrogels. Here, we describe the creation of virtual masks that allow for image-guided laser control; the photopolymerization of a micromolded PEGDA hydrogel, suitable for microfluidic network fabrication and pressure head-driven flow; the setup and use of a commercially available laser scanning confocal microscope paired with a femtosecond pulsed Ti:S laser to induce hydrogel degradation; and the imaging of fabricated microfluidic networks using fluorescent species and confocal microscopy. Much of the protocol is focused on the proper setup and implementation of the microscope software and microscope macro, as these are crucial steps in using a commercial microscope for microfluidic fabrication purposes that contain a number of intricacies. The image-guided component of this technique allows for the implementation of 3D image stacks or user-generated 3D models, thereby allowing for creative microfluidic design and for the fabrication of complex microfluidic systems of virtually any configuration. With an expected impact in tissue engineering, the methods outlined in this protocol could aid in the fabrication of advanced biomimetic microtissue constructs for organ- and human-on-a-chip devices. By mimicking the complex architecture, tortuosity, size, and density of in vivo vasculature, essential biological transport processes can be replicated in these constructs, leading to more accurate in vitro modeling of drug pharmacokinetics and disease.

  14. Image-guided tumor ablation: standardization of terminology and reporting criteria.

    PubMed

    Goldberg, S Nahum; Grassi, Clement J; Cardella, John F; Charboneau, J William; Dodd, Gerald D; Dupuy, Damian E; Gervais, Debra A; Gillams, Alice R; Kane, Robert A; Lee, Fred T; Livraghi, Tito; McGahan, John; Phillips, David A; Rhim, Hyunchul; Silverman, Stuart G; Solbiati, Luigi; Vogl, Thomas J; Wood, Bradford J; Vedantham, Suresh; Sacks, David

    2009-07-01

    The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

  15. Real-time three-dimensional Fourier-domain optical coherence tomography video image guided microsurgeries

    PubMed Central

    Huang, Yong; Zhang, Kang; Ibrahim, Zuhaib; Cha, Jaepyeong; Lee, W. P. Andrew; Brandacher, Gerald; Gehlbach, Peter L.

    2012-01-01

    Abstract. The authors describe the development of an ultrafast three-dimensional (3D) optical coherence tomography (OCT) imaging system that provides real-time intraoperative video images of the surgical site to assist surgeons during microsurgical procedures. This system is based on a full-range complex conjugate free Fourier-domain OCT (FD-OCT). The system was built in a CPU-GPU heterogeneous computing architecture capable of video OCT image processing. The system displays at a maximum speed of 10  volume/s for an image volume size of 160×80×1024 (X×Y×Z) pixels. We have used this system to visualize and guide two prototypical microsurgical maneuvers: microvascular anastomosis of the rat femoral artery and ultramicrovascular isolation of the retinal arterioles of the bovine retina. Our preliminary experiments using 3D-OCT-guided microvascular anastomosis showed optimal visualization of the rat femoral artery (diameter<0.8  mm), instruments, and suture material. Real-time intraoperative guidance helped facilitate precise suture placement due to optimized views of the vessel wall during anastomosis. Using the bovine retina as a model system, we have performed “ultra microvascular” feasibility studies by guiding handheld surgical micro-instruments to isolate retinal arterioles (diameter∼0.1  mm). Isolation of the microvessels was confirmed by successfully passing a suture beneath the vessel in the 3D imaging environment. PMID:23224164

  16. An automatic registration method for frameless stereotaxy, image guided surgery, and enhanced reality visualization

    SciTech Connect

    Grimson, W.E.L.; Lozano-Perez, T.; Ettinger, G.J. |; White, S.J.; Wells, W.M. III |; Kikinis, R.

    1996-04-01

    There is a need for frameless guidance systems to help surgeons plan the exact location for incisions, to define the margins of tumors, and to precisely identify locations of neighboring critical structures. The authors have developed an automatic technique for registering clinical data, such as segmented magnetic resonance imaging (MRI) or computed tomography (CT) reconstructions, with any view of the patient on the operating table. They demonstrate on the specific example of neurosurgery. The method enables a visual mix of live video of the patient and the segmented three-dimensional (3-D) MRI or CT model. This supports enhanced reality techniques for planning and guiding neurosurgical procedures and allows them to interactively view extracranial or intracranial structures nonintrusively. Extensions of the method include image guided biopsies, focused therapeutic procedures, and clinical studies involving change detection over time sequences of images.

  17. Hard and soft nanoparticles for image-guided surgery in nanomedicine

    NASA Astrophysics Data System (ADS)

    Locatelli, Erica; Monaco, Ilaria; Comes Franchini, Mauro

    2015-08-01

    The use of hard and/or soft nanoparticles for therapy, collectively called nanomedicine, has great potential in the battle against cancer. Major research efforts are underway in this area leading to development of new drug delivery approaches and imaging techniques. Despite this progress, the vast majority of patients who are affected by cancer today sadly still need surgical intervention, especially in the case of solid tumors. An important perspective for researchers is therefore to provide even more powerful tools to the surgeon for pre- and post-operative approaches. In this context, image-guided surgery, in combination with nanotechnology, opens a new strategy to win this battle. In this perspective, we will analyze and discuss the recent progress with nanoparticles of both metallic and biomaterial composition, and their use to develop powerful systems to be applied in image-guided surgery.

  18. Drug-loaded biodegradable microspheres for image-guided combinatory epigenetic therapy in cells

    NASA Astrophysics Data System (ADS)

    Xu, Ronald X.; Xu, Jeff S.; Zuo, Tao; Shen, Rulong; Huang, Tim H.; Tweedle, Michael F.

    2011-02-01

    We synthesize drug-loaded poly (lactic-co-glycolic acid) (PLGA) microspheres for image-guided combinatory epigenetic therapy in MCF-10A human mammary epithelial cells. LY294002 and Nile Red are encapsulated in microspheres for sustained drug release and fluorescence microscopic imaging. Drug-loaded microspheres target MCF-10A cells through a three-step binding process involving biotinylated antibody, streptavidin, and biotinylated microspheres. LY294002 loaded microspheres and 5-Aza-2-deoxycytidine are applied to MCF-10A cells for combinatory PI3K/AKT inhibition and deoxyribonucleic acid (DNA) demethylation. Our study implies the technical potential of disease targeting and image-guided combinatory epigenetic therapy using drug-loaded multifunctional biodegradable PLGA microspheres.

  19. Cone-beam CT with a flat-panel detector: From image science to image-guided surgery

    NASA Astrophysics Data System (ADS)

    Siewerdsen, Jeffrey H.

    2011-08-01

    The development of large-area flat-panel X-ray detectors (FPDs) has spurred investigation in a spectrum of advanced medical imaging applications, including tomosynthesis and cone-beam CT (CBCT). Recent research has extended image quality metrics and theoretical models to such applications, providing a quantitative foundation for the assessment of imaging performance as well as a general framework for the design, optimization, and translation of such technologies to new applications. For example, cascaded systems models of the Fourier domain metrics, such as noise-equivalent quanta (NEQ), have been extended to these modalities to describe the propagation of signal and noise through the image acquisition and reconstruction chain and to quantify the factors that govern spatial resolution, image noise, and detectability. Moreover, such models have demonstrated basic agreement with human observer performance for a broad range of imaging conditions and imaging tasks. These developments in image science have formed a foundation for the knowledgeable development and translation of CBCT to new applications in image-guided interventions—for example, CBCT implemented on a mobile surgical C-arm for intraoperative 3D imaging. The ability to acquire high-quality 3D images on demand during surgical intervention overcomes conventional limitations of surgical guidance in the context of preoperative images alone. A prototype mobile C-arm developed in academic-industry partnership demonstrates CBCT with low radiation dose, sub-mm spatial resolution, and soft-tissue visibility potentially approaching that of diagnostic CT. Integration of the 3D imaging system with real-time tracking, deformable registration, endoscopic video, and 3D visualization offers a promising addition to the surgical arsenal in interventions ranging from head-and-neck/skull base surgery to spine, orthopaedic, thoracic, and abdominal surgeries. Cadaver studies show the potential for significant boosts in

  20. Near-IR Image-Guided Laser Ablation of Demineralization on Tooth Occlusal Surfaces

    PubMed Central

    Tom, Henry; Chan, Kenneth H.; Darling, Cynthia L.; Fried, Daniel

    2016-01-01

    Introduction Studies have shown that reflectance images at near-IR wavelengths coincident with higher water absorption are well-suited for image-guided laser ablation of carious lesions since the contrast between sound and demineralized enamel is extremely high and interference from stains is minimized. The objective of this study was to demonstrate that near-IR reflectance images taken at a wavelength range of 1,500–1,700 nm can be used to guide a 9.3 μm CO2 laser for the selective ablation of early demineralization on tooth occlusal surfaces. Methods The occlusal surfaces of ten sound human molars were used in this in vitro study. Shallow simulated caries lesions with random patterns and varying depth and position were produced on tooth occlusal surfaces. Sequential near-IR reflectance images at 1,500–1,700 nm were used to guide the laser for the selective removal of the demineralized enamel. Digital microscopy and polarization sensitive optical coherence tomography (PS-OCT) were used to assess selectivity. Results Images taken before and after lesion removal suggest that the demineralized areas were removed with high selectivity. Although the estimated volume of tissue ablated was typically higher than the initial lesion volume measured with PS-OCT, the volume of enamel removed by the laser correlated well with the initial lesion volume. Conclusion Sequential near-IR reflectance images at 1,500–1,700 nm can be used to guide a 9.3 μm CO2 laser for the selective ablation of early demineralization on tooth occlusal surfaces. PMID:26763111

  1. Value of MR contrast media in image-guided body interventions.

    PubMed

    Saeed, Maythem; Wilson, Mark

    2012-01-28

    In the past few years, there have been multiple advances in magnetic resonance (MR) instrumentation, in vivo devices, real-time imaging sequences and interventional procedures with new therapies. More recently, interventionists have started to use minimally invasive image-guided procedures and local therapies, which reduce the pain from conventional surgery and increase drug effectiveness, respectively. Local therapy also reduces the systemic dose and eliminates the toxic side effects of some drugs to other organs. The success of MR-guided procedures depends on visualization of the targets in 3D and precise deployment of ablation catheters, local therapies and devices. MR contrast media provide a wealth of tissue contrast and allows 3D and 4D image acquisitions. After the development of fast imaging sequences, the clinical applications of MR contrast media have been substantially expanded to include pre- during- and post-interventions. Prior to intervention, MR contrast media have the potential to localize and delineate pathologic tissues of vital organs, such as the brain, heart, breast, kidney, prostate, liver and uterus. They also offer other options such as labeling therapeutic agents or cells. During intervention, these agents have the capability to map blood vessels and enhance the contrast between the endovascular guidewire/catheters/devices, blood and tissues as well as direct therapies to the target. Furthermore, labeling therapeutic agents or cells aids in visualizing their delivery sites and tracking their tissue distribution. After intervention, MR contrast media have been used for assessing the efficacy of ablation and therapies. It should be noted that most image-guided procedures are under preclinical research and development. It can be concluded that MR contrast media have great value in preclinical and some clinical interventional procedures. Future applications of MR contrast media in image-guided procedures depend on their safety, tolerability

  2. Robotically-adjustable microstereotactic frames for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Kratchman, Louis B.; Fitzpatrick, J. Michael

    2013-03-01

    Stereotactic frames are a standard tool for neurosurgical targeting, but are uncomfortable for patients and obstruct the surgical field. Microstereotactic frames are more comfortable for patients, provide better access to the surgical site, and have grown in popularity as an alternative to traditional stereotactic devices. However, clinically available microstereotactic frames require either lengthy manufacturing delays or expensive image guidance systems. We introduce a robotically-adjusted, disposable microstereotactic frame for deep brain stimulation surgery that eliminates the drawbacks of existing microstereotactic frames. Our frame can be automatically adjusted in the operating room using a preoperative plan in less than five minutes. A validation study on phantoms shows that our approach provides a target positioning error of 0.14 mm, which exceeds the required accuracy for deep brain stimulation surgery.

  3. Tailored Near-Infrared Contrast Agents for Image Guided Surgery

    PubMed Central

    Njiojob, Costyl N.; Owens, Eric A.; Narayana, Lakshminarayana; Hyun, Hoon; Choi, Hak Soo; Henary, Maged

    2015-01-01

    The success of near-infrared (NIR) fluorescence to be employed for intraoperative imaging relies on the ability to develop a highly stable, NIR fluorescent, nontoxic, biocompatible, and highly excreted compound that retains a reactive functionality for conjugation to a cancer-recognizing peptide. Herein, systematic modifications to previously detailed fluorophore ZW800-1 are explored. Specific modifications, including the isosteric replacement of the O atom of ZW800-1, include nucleophilic amine and sulfur species attached to the heptamethine core. These novel compounds have shown similar satisfactory results in biodistribution and clearance while also expressing increased stability in serum. Most importantly, all of the synthesized and evaluated compounds display a reactive functionality (either a free amino group or carboxylic acid moiety) for further bioconjugation. The results obtained from the newly prepared derivatives demonstrate that the central substitution with the studied linking agents retains the ultralow background in vivo performance of the fluorophores regardless of the total net charge. PMID:25711712

  4. Radio Tomography and Imaging of Ionospheric Disturbances Caused by Active Experiments

    NASA Astrophysics Data System (ADS)

    Kunitsyn, Viacheslav; Padokhin, Artem; Andreeva, Elena; Tereshchenko, Evgeny; Nesterov, Ivan; Vladimir Frolov, S.

    We present the results of the radiotomographic imaging of the artificial ionospheric disturbances obtained in the experiments on the modification of the midlatitude ionosphere by powerful HF radiowaves carried out during last decade at the Sura heating facility. The experiments were conducted using both O- and X- mode radiowaves at frequencies lower than critical frequency of the ionospheric F2 layer both in daytime and nighttime ionosphere. Various schemes of the radiation of the heating wave were used including square wave modulation of the effective radiated power (ERP) at various frequencies and power stepping. Radio transmissions of the low- (Parus/Tsikada) and high-orbital (GPS/GLONASS) navigational satellites received at the mobile network of receiving sites were used for the remote sensing of the heated area of the ionosphere. We study the variations in TEC caused by HF heating showing that the GNSS TEC spectra often contain frequency components corresponding to the modulation periods of the ERP of the heating wave. The manifestations of the heating-induced variations in TEC are most prominent in the area of magnetic zenith of the pumping wave. In this work we also present the radiotomographic reconstructions of the spatial structure of the disturbed area of the ionosphere corresponding to the directivity pattern of the heater as well as the spatial structure of the wave-like disturbances, which are possibly AGWs, diverging from the heated area of the ionosphere. We also compare the effects obsereved during artificial heating experiments with those obsereved during rocket launches and powerful industiral explosions. The possibility of generation of electromagnetic waves by moving wave-like structures in ionosphere (like AGWs induced by HF-heating observed in our experiments) is also addressed in this work. The authors acknowledge the support of the Russian Foundation for Basic Research (grants № 13-05-01122, 14-05-31445, 14-05-00855, 14-05-10069), grants

  5. Pharmacodynamic imaging guides dosing of a selective estrogen receptor degrader

    PubMed Central

    Heidari, Pedram; Deng, Francis; Esfahani, Shadi A.; Leece, Alicia K.; Shoup, Timothy M.; Vasdev, Neil; Mahmood, Umar

    2015-01-01

    Purpose Estrogen receptor (ER) targeting is key in management of receptor-positive breast cancer (BrCa). Currently, there are no methods to optimize anti-ER therapy dosing. This study assesses the utility of 16α-18F-fluoroestradiol (18F-FES) PET for fulvestrant dose optimization in a preclinical ER+ BrCa model. Experimental Design In vitro, 18F-FES retention was compared to ERα protein expression (ELISA) and ESR1 mRNA transcription (qPCR) in MCF7 cells (ER+) after treatment with different fulvestrant doses. MCF7 xenografts were grown in ovariectomized nude mice and assigned to vehicle, low- (0.05mg), medium- (0.5mg) or high-dose (5mg) fulvestrant treatment groups (5–7 per group). Two and three days after fulvestrant treatment, PET/CT was performed using 18F-FES and 18F-FDG, respectively. ER expression was assessed by immunohistochemistry, ELISA, and qPCR on xenografts. Tumor proliferation was assessed using Ki-67 immunohistochemistry. Results In vitro, we observed a parallel graded reduction in 18F-FES uptake and ER expression with increased fulvestrant doses, despite enhancement of ER mRNA transcription. In xenografts, ER expression significantly decreased with increased fulvestrant dose, despite similar mRNA expression and Ki-67 staining among the treatment groups. We observed a significant dose-dependent reduction of 18F-FES PET mean standardized uptake value (SUVmean) with fulvestrant treatment, but no significant difference among the treatment groups in 18F-FDG PET SUVmean.. Conclusion We demonstrated that 18F-FES uptake mirrors the dose-dependent changes in functional ER expression with fulvestrant resulting in ER degradation and/or blockade; these precede changes in tumor metabolism and proliferation. Quantitative 18F-FES PET may be useful for tracking early efficacy of ER blockade/degradation and guiding ER-targeted therapy dosing in BrCa patients. PMID:25609068

  6. Design of a Novel MRI Compatible Manipulator for Image Guided Prostate Interventions

    PubMed Central

    Krieger, Axel; Susil, Robert C.; Ménard, Cynthia; Coleman, Jonathan A.; Fichtinger, Gabor; Atalar, Ergin

    2012-01-01

    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 and open configuration MRI scanners. Preliminary in vivo canine experiments and first clinical trials are reported. PMID:15709668

  7. Magnetic particle imaging: advancements and perspectives for real-time in vivo monitoring and image-guided therapy

    NASA Astrophysics Data System (ADS)

    Pablico-Lansigan, Michele H.; Situ, Shu F.; Samia, Anna Cristina S.

    2013-05-01

    Magnetic particle imaging (MPI) is an emerging biomedical imaging technology that allows the direct quantitative mapping of the spatial distribution of superparamagnetic iron oxide nanoparticles. MPI's increased sensitivity and short image acquisition times foster the creation of tomographic images with high temporal and spatial resolution. The contrast and sensitivity of MPI is envisioned to transcend those of other medical imaging modalities presently used, such as magnetic resonance imaging (MRI), X-ray scans, ultrasound, computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this review, we present an overview of the recent advances in the rapidly developing field of MPI. We begin with a basic introduction of the fundamentals of MPI, followed by some highlights over the past decade of the evolution of strategies and approaches used to improve this new imaging technique. We also examine the optimization of iron oxide nanoparticle tracers used for imaging, underscoring the importance of size homogeneity and surface engineering. Finally, we present some future research directions for MPI, emphasizing the novel and exciting opportunities that it offers as an important tool for real-time in vivo monitoring. All these opportunities and capabilities that MPI presents are now seen as potential breakthrough innovations in timely disease diagnosis, implant monitoring, and image-guided therapeutics.

  8. Current brachytherapy quality assurance guidance: does it meet the challenges of emerging image-guided technologies?

    PubMed

    Williamson, Jeffrey F

    2008-01-01

    In the past decade, brachytherapy has shifted from the traditional surgical paradigm to more modern three-dimensional image-based planning and delivery approaches. The role of intraoperative and multimodality image-based planning is growing. Published American Association of Physicists in Medicine, American College of Radiology, European Society for Therapeutic Radiology and Oncology, and International Atomic Energy Agency quality assurance (QA) guidelines largely emphasize the QA of planning and delivery devices rather than processes. These protocols have been designed to verify compliance with major performance specifications and are not risk based. With some exceptions, complete and clinically practical guidance exists for sources, QA instrumentation, non-image-based planning systems, applicators, remote afterloading systems, dosimetry, and calibration. Updated guidance is needed for intraoperative imaging systems and image-based planning systems. For non-image-based brachytherapy, the American Association of Physicists in Medicine Task Group reports 56 and 59 provide reasonable guidance on procedure-specific process flow and QA. However, improved guidance is needed even for established procedures such as ultrasound-guided prostate implants. Adaptive replanning in brachytherapy faces unsolved problems similar to that of image-guided adaptive external beam radiotherapy.

  9. Recognition-based segmentation and registration method for image guided shoulder surgery.

    PubMed

    Chaoui, J; Hamitouche, C; Stindel, E; Roux, C

    2011-01-01

    For any image guided surgery, independently of the technique which is used (navigation, templates, robotics), it is necessary to get a 3D bone surface model from CT or MR images. Such model is used for planning, registration and visualization. We report that graphical representation of patient bony structure and the surgical tools, interconnectively with the tracking device and patient-to-image registration are crucial components in such a system. For Total Shoulder Arthroplasty (TSA), there are many challenges, The most of cases that we are working with are pathological cases such as rheumatoid arthritis, osteoarthritis disease. The CT images of these cases often show a fusion area between the glenoid cavity and the humeral head. They also show severe deformations of the humeral head surface that result in a loss of contours. This fusion area and image quality problems are also amplified by well-known CT-scan artifacts like beam-hardening or partial volume effects. The state of the art shows that several segmentation techniques, applied to CT-Scans of the shoulder, have already been disclosed. Unfortunately, their performances, when used on pathological data, are quite poor [1, 2]. The aim of this paper is to present a new image guided surgery system based on CT scan of the patient and using bony structure recognition, morphological analysis for the operated region and robust image-to-patient registration.

  10. Remote sensing image enhancement based on the combination of nonsubsampled shearlet transform and guided filtering

    NASA Astrophysics Data System (ADS)

    Lv, Duliang; Jia, Zhenhong; Yang, Jie; Kasabov, Nikola

    2016-10-01

    Aiming at the characteristics of remote sensing images with low-contrast, weak edge preservation, and poor resolution textual information, an image enhancement method that combines nonsubsampled shearlet transform (NSST) and guided filtering is presented. First, histogram equalization is applied to the remote sensing image. Second, the image is decomposed into a low frequency component and several high frequency components by NSST. Then, a linear stretch is adopted for the coefficients of the low-frequency component to improve the contrast of the original image; the threshold method is used to restrain the noise in the high-frequency components, then guided filtering is used for dealing with the high-frequency components, improving the detail information and edge-gradient retention ability. Finally, the final enhanced image is reconstructed by applying the inverse NSST to the processed low- and high-frequency components. The results show that the algorithm can significantly improve the visual impression of the image. Compared with the proposed algorithms in recent years, the average gradient and information entropy are significantly improved and the running time is shortened.

  11. Review of fluorescence guided surgery systems: identification of key performance capabilities beyond indocyanine green imaging

    NASA Astrophysics Data System (ADS)

    DSouza, Alisha V.; Lin, Huiyun; Henderson, Eric R.; Samkoe, Kimberley S.; Pogue, Brian W.

    2016-08-01

    There is growing interest in using fluorescence imaging instruments to guide surgery, and the leading options for open-field imaging are reviewed here. While the clinical fluorescence-guided surgery (FGS) field has been focused predominantly on indocyanine green (ICG) imaging, there is accelerated development of more specific molecular tracers. These agents should help advance new indications for which FGS presents a paradigm shift in how molecular information is provided for resection decisions. There has been a steady growth in commercially marketed FGS systems, each with their own differentiated performance characteristics and specifications. A set of desirable criteria is presented to guide the evaluation of instruments, including: (i) real-time overlay of white-light and fluorescence images, (ii) operation within ambient room lighting, (iii) nanomolar-level sensitivity, (iv) quantitative capabilities, (v) simultaneous multiple fluorophore imaging, and (vi) ergonomic utility for open surgery. In this review, United States Food and Drug Administration 510(k) cleared commercial systems and some leading premarket FGS research systems were evaluated to illustrate the continual increase in this performance feature base. Generally, the systems designed for ICG-only imaging have sufficient sensitivity to ICG, but a fraction of the other desired features listed above, with both lower sensitivity and dynamic range. In comparison, the emerging research systems targeted for use with molecular agents have unique capabilities that will be essential for successful clinical imaging studies with low-concentration agents or where superior rejection of ambient light is needed. There is no perfect imaging system, but the feature differences among them are important differentiators in their utility, as outlined in the data and tables here.

  12. Observations of solar coronal holes using radio (GMRT & GRH), extreme ultra-violet (SOHO-EIT) and X-ray (GOES-SXI) imaging instruments

    NASA Astrophysics Data System (ADS)

    Madsen, F. R. H.; Ramesh, R.; Ananthakrishnan, S.; Subramanian, P.; Cecatto, J. R.; Sawant, H. S.

    Solar observations with the Giant Metrewave Radio Telescope GMRT on 06 04 2005 at 150 MHz show evidence for a radio counterpart to a Coronal Hole CH observed as a depression in the radio brightness distribution on the solar disk In this work we compare the structural details of the radio CH using the GMRT observations and the Extreme Ultra Violet EUV and Soft X-Ray SXR images obtained with the SoHO EIT and GOES SXI respectively We also study the density temperature inside the same CH using 115 MHz data from the Gauribidanur Radioheliograph GRH We present and discuss our results for the radio counterpart to this CH focusing on the comparison of its position and size as determined from EUV and SXR with the parameters determined from the GMRT map and on the determination of plasma parameters from the GRH map

  13. Progressive cone beam CT dose control in image-guided radiation therapy

    PubMed Central

    Yan, Hao; Zhen, Xin; Cerviño, Laura; Jiang, Steve B.; Jia, Xun

    2013-01-01

    Purpose: Cone beam CT (CBCT) in image-guided radiotherapy (IGRT) offers a tremendous advantage for treatment guidance. The associated imaging dose is a clinical concern. One unique feature of CBCT-based IGRT is that the same patient is repeatedly scanned during a treatment course, and the contents of CBCT images at different fractions are similar. The authors propose a progressive dose control (PDC) scheme to utilize this temporal correlation for imaging dose reduction. Methods: A dynamic CBCT scan protocol, as opposed to the static one in the current clinical practice, is proposed to gradually reduce the imaging dose in each treatment fraction. The CBCT image from each fraction is processed by a prior-image based nonlocal means (PINLM) module to enhance its quality. The increasing amount of prior information from previous CBCT images prevents degradation of image quality due to the reduced imaging dose. Two proof-of-principle experiments have been conducted using measured phantom data and Monte Carlo simulated patient data with deformation. Results: In the measured phantom case, utilizing a prior image acquired at 0.4 mAs, PINLM is able to improve the image quality of a CBCT acquired at 0.2 mAs by reducing the noise level from 34.95 to 12.45 HU. In the synthetic patient case, acceptable image quality is maintained at four consecutive fractions with gradually decreasing exposure levels of 0.4, 0.1, 0.07, and 0.05 mAs. When compared with the standard low-dose protocol of 0.4 mAs for each fraction, an overall imaging dose reduction of more than 60% is achieved. Conclusions: PINLM-PDC is able to reduce CBCT imaging dose in IGRT utilizing the temporal correlations among the sequence of CBCT images while maintaining the quality. PMID:23718579

  14. Dosimetric evaluation of the OneDose MOSFET for measuring kilovoltage imaging dose from image-guided radiotherapy procedures

    SciTech Connect

    Ding, George X.; Coffey, Charles W.

    2010-09-15

    Purpose: The purpose of this study is to investigate the feasibility of using a single-use dosimeter, OneDose MOSFET designed for in vivo patient dosimetry, for measuring the radiation dose from kilovoltage (kV) x rays resulting from image-guided procedures. Methods: The OneDose MOSFET dosimeters were precalibrated by the manufacturer using Co-60 beams. Their energy response and characteristics for kV x rays were investigated by using an ionization chamber, in which the air-kerma calibration factors were obtained from an Accredited Dosimetry Calibration Laboratory (ADCL). The dosimetric properties have been tested for typical kV beams used in image-guided radiation therapy (IGRT). Results: The direct dose reading from the OneDose system needs to be multiplied by a correction factor ranging from 0.30 to 0.35 for kilovoltage x rays ranging from 50 to 125 kVp, respectively. In addition to energy response, the OneDose dosimeter has up to a 20% reduced sensitivity for beams (70-125 kVp) incident from the back of the OneDose detector. Conclusions: The uncertainty in measuring dose resulting from a kilovoltage beam used in IGRT is approximately 20%; this uncertainty is mainly due to the sensitivity dependence of the incident beam direction relative to the OneDose detector. The ease of use may allow the dosimeter to be suitable for estimating the dose resulting from image-guided procedures.

  15. Algorithm-enabled exploration of image-quality potential of cone-beam CT in image-guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Han, Xiao; Pearson, Erik; Pelizzari, Charles; Al-Hallaq, Hania; Sidky, Emil Y.; Bian, Junguo; Pan, Xiaochuan

    2015-06-01

    Kilo-voltage (KV) cone-beam computed tomography (CBCT) unit mounted onto a linear accelerator treatment system, often referred to as on-board imager (OBI), plays an increasingly important role in image-guided radiation therapy. While the FDK algorithm is currently used for reconstructing images from clinical OBI data, optimization-based reconstruction has also been investigated for OBI CBCT. An optimization-based reconstruction involves numerous parameters, which can significantly impact reconstruction properties (or utility). The success of an optimization-based reconstruction for a particular class of practical applications thus relies strongly on appropriate selection of parameter values. In the work, we focus on tailoring the constrained-TV-minimization-based reconstruction, an optimization-based reconstruction previously shown of some potential for CBCT imaging conditions of practical interest, to OBI imaging through appropriate selection of parameter values. In particular, for given real data of phantoms and patient collected with OBI CBCT, we first devise utility metrics specific to OBI-quality-assurance tasks and then apply them to guiding the selection of parameter values in constrained-TV-minimization-based reconstruction. The study results show that the reconstructions are with improvement, relative to clinical FDK reconstruction, in both visualization and quantitative assessments in terms of the devised utility metrics.

  16. Algorithm-enabled exploration of image-quality potential of cone-beam CT in image-guided radiation therapy

    PubMed Central

    Han, Xiao; Pearson, Erik; Pelizzari, Charles; Al-Hallaq, Hania; Sidky, Emil Y.; Bian, Junguo; Pan, Xiaochuan

    2015-01-01

    Kilo-voltage (KV) cone-beam computed tomography (CBCT) unit mounted onto a linear accelerator treatment system, often referred to as on-board imager (OBI), plays an increasingly important role in image-guide radiation therapy. While the FDK algorithm is used currently for reconstructing images from clinical OBI data, optimization-based reconstruction has also been investigated for OBI CBCT. An optimization-based reconstruction involves numerous parameters, which can significantly impact reconstruction properties (or utility). The success of an optimization-based reconstruction for a particular class of practical applications thus relies strongly on appropriate selection of parameter values. In the work, we focus on tailoring the constrained-TV-minimization-based reconstruction, an optimization-based reconstruction previously shown of some potential for CBCT imaging conditions of practical interest, to OBI imaging through appropriate selection of parameter values. In particular, for given real data of phantoms and patient collected with OBI CBCT, we first devise utility metrics specific to OBI-quality-assurance tasks and then apply them to guiding the selection of parameter values in constrained-TV-minimization-based reconstruction. The study results show that the reconstructions are with improvement, relative to clinical FDK reconstruction, in both visualization and quantitative assessments in terms of the devised utility metrics. PMID:26020490

  17. Evaluation of Imaging Dose From Different Image Guided Systems During Head and Neck Radiotherapy: A Phantom Study.

    PubMed

    Cheng, Chun Shing; Jong, Wei Loong; Ung, Ngie Min; Wong, Jeannie Hsiu Ding

    2016-12-09

    This work evaluated and compared the absorbed doses to selected organs in the head and neck region from the three image guided radiotherapy systems: cone-beam computed tomography (CBCT) and kilovoltage (kV) planar imaging using the On-board Imager(®) (OBI) as well as the ExacTrac(®) X-ray system, all available on the Varian Novalis TX linear accelerator. The head and neck region of an anthropomorphic phantom was used to simulate patients' head within the imaging field. Nanodots optically stimulated luminescent dosemeters were positioned at selected sites to measure the absorbed doses. CBCT was found to be delivering the highest dose to internal organs while OBI-2D gave the highest doses to the eye lenses. The setting of half-rotation in CBCT effectively reduces the dose to the eye lenses. Daily high-quality CBCT verification was found to increase the secondary cancer risk by 0.79%.

  18. In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Que, Ivo; Kong, Xianggui; Zhang, Youlin; Tu, Langping; Chang, Yulei; Wang, Tong Tong; Chan, Alan; Löwik, Clemens W. G. M.; Zhang, Hong

    2015-09-01

    A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the 1O2 production, resulting in the improvement of the therapeutic effect; (ii) realizing in vivo NIR 808 nm image-guided PDT with both excitation (980 nm) and emission (808 nm) light falling in the biological window of tissues, which minimized auto-fluorescence, reduced light scatting and improved the imaging contrast and depth, and thus guaranteed noninvasive diagnostic accuracy. In vivo and ex vivo tests demonstrated its favorable bio-distribution, tumor-selectivity and high therapeutic efficacy. Owing to the effective ligand exchange strategy and the excellent intrinsic photophysical properties of C60, 1O2 production yield was improved, suggesting that a low 980 nm irradiation dosage (351 J cm-2) and a short treatment time (15 min) were sufficient to perform NIR (980 nm) to NIR (808 nm) image-guided PDT. Our work enriches the understanding of UCNP-based PDT nanophotosensitizers and highlights their potential use in future NIR image-guided noninvasive deep cancer therapy.A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the 1O2 production, resulting in the improvement of the therapeutic effect; (ii

  19. NICMOS Imaging of the Dusty Microjansky Radio Source VLA J123642+621331 at z = 4.424.

    PubMed

    Waddington; Windhorst; Cohen; Partridge; Spinrad; Stern

    1999-12-01

    We present the discovery of a radio galaxy at a likely redshift of z=4.424 in one of the flanking fields of the Hubble Deep Field (HDF). Radio observations with the Very Large Array and MERLIN centered on the HDF yielded a complete sample of microjansky radio sources, of which about 20% have no optical counterpart to Iimages in the F110W (J110) and F160W (H160) filters. VLA J123642+621331 has a single emission line at 6595 Å, which we identify with Lyalpha at z=4.424. We argue that this faint (H160=23.9 mag), compact (re approximately 0&farcs;2), red (I814-K=2.0) object is most likely a dusty, star-forming galaxy with an embedded active nucleus.

  20. Polydopamine Nanoparticles as a Versatile Molecular Loading Platform to Enable Imaging-guided Cancer Combination Therapy

    PubMed Central

    Dong, Ziliang; Gong, Hua; Gao, Min; Zhu, Wenwen; Sun, Xiaoqi; Feng, Liangzhu; Fu, Tingting; Li, Yonggang; Liu, Zhuang

    2016-01-01

    Cancer combination therapy to treat tumors with different therapeutic approaches can efficiently improve treatment efficacy and reduce side effects. Herein, we develop a theranostic nano-platform based on polydopamine (PDA) nanoparticles, which then are exploited as a versatile carrier to allow simultaneous loading of indocyanine green (ICG), doxorubicin (DOX) and manganese ions (PDA-ICG-PEG/DOX(Mn)), to enable imaging-guided chemo & photothermal cancer therapy. In this system, ICG acts as a photothermal agent, which shows red-shifted near-infrared (NIR) absorbance and enhanced photostability compared with free ICG. DOX, a model chemotherapy drug, is then loaded onto the surface of PDA-ICG-PEG with high efficiency. With Mn2+ ions intrinsically chelated, PDA-ICG-PEG/DOX(Mn) is able to offer contrast under T1-weighted magnetic resonance (MR) imaging. In a mouse tumor model, the MR imaging-guided combined chemo- & photothermal therapy achieves a remarkable synergistic therapeutic effect compared with the respective single treatment modality. This work demonstrates that PDA nanoparticles could serve as a versatile molecular loading platform for MR imaging guided combined chemo- & photothermal therapy with minimal side effects, showing great potential for cancer theranostics. PMID:27217836

  1. IMAGE-GUIDED EVALUATION AND MONITORING OF TREATMENT RESPONSE IN PATIENTS WITH DRY EYE DISEASE

    PubMed Central

    Hamrah, Pedram

    2014-01-01

    Dry eye disease (DED) is one of the most common ocular disorders worldwide. The pathophysiological mechanisms involved in the development of DED are not well understood and thus treating DED has been a significant challenge for ophthalmologists. Most of the currently available diagnostic tests demonstrate low correlation to patient symptoms and have low reproducibility. Recently, sophisticated in vivo imaging modalities have become available for patient care, namely, in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT). These emerging modalities are powerful and non-invasive, allowing real-time visualization of cellular and anatomical structures of the cornea and ocular surface. Here we discuss how, by providing both qualitative and quantitative assessment, these techniques can be used to demonstrate early subclinical disease, grade layer-by-layer severity, and allow monitoring of disease severity by cellular alterations. Imaging-guided stratification of patients may also be possible in conjunction with clinical examination methods. Visualization of subclinical changes and stratification of patients in vivo, allows objective image-guided evaluation of tailored treatment response based on cellular morphological alterations specific to each patient. This image-guided approach to DED may ultimately improve patient outcomes and allow studying the efficacy of novel therapies in clinical trials. PMID:24696045

  2. Near-infrared dye bound albumin with separated imaging and therapy wavelength channels for imaging-guided photothermal therapy.

    PubMed

    Chen, Qian; Wang, Chao; Zhan, Zhixiong; He, Weiwei; Cheng, Zhenping; Li, Youyong; Liu, Zhuang

    2014-09-01

    Development of theranostic agent for imaging-guided photothermal therapy has been of great interest in the field of nanomedicine. However, if fluorescent imaging and photothermal ablation are conducted with the same wavelength of light, the requirements of the agent's quantum yield (QY) for imaging and therapy are controversial. In this work, our synthesized near-infrared dye, IR825, is bound with human serum albumin (HSA), forming a HSA-IR825 complex with greatly enhanced fluorescence under 600 nm excitation by as much as 100 folds compared to that of free IR825, together with a rather high absorbance but low fluorescence QY at 808 nm. Since high QY that is required for fluorescence imaging would result in reduced photothermal conversion efficiency, the unique optical behavior of HSA-IR825 enables imaging and photothermal therapy at separated wavelengths both with optimized performances. We thus use HSA-IR825 for imaging-guided photothermal therapy in an animal tumor model. As revealed by in vivo fluorescence imaging, HSA-IR825 upon intravenous injection shows high tumor uptake likely owing to the enhanced permeability and retention effect, together with low levels of retentions in other organs. While HSA is an abundant protein in human serum, IR825 is able to be excreted by renal excretion as evidenced by high-performance liquid chromatography (HPLC). In vivo tumor treatment experiment is finally carried out with HSA-IR825, achieving 100% of tumor ablation in mice using a rather low dose of IR825. Our work presents a safe, simple, yet imageable photothermal nanoprobe, promising for future clinical translation in cancer treatment.

  3. Depletion of New Neurons by Image Guided Irradiation

    PubMed Central

    Tan, Y.-F.; Rosenzweig, S.; Jaffray, D.; Wojtowicz, J. M.

    2011-01-01

    Ionizing radiation continues to be a relevant tool in both imaging and the treatment of cancer. Experimental uses of focal irradiation have recently been expanded to studies of new neurons in the adult brain. Such studies have shown cognitive deficits following radiation treatment and raised caution as to possible unintentional effects that may occur in humans. Conflicting outcomes of the effects of irradiation on adult neurogenesis suggest that the effects are either transient or permanent. In this study, we used an irradiation apparatus employed in the treatment of human tumors to assess radiation effects on rat neurogenesis. For subjects we used adult male rats (Sprague-Dawley) under anesthesia. The irradiation beam was directed at the hippocampus, a center for learning and memory, and the site of neurogenic activity in adult brain. The irradiation was applied at a dose-rate 0.6 Gy/min for total single-fraction, doses ranging from 0.5 to 10.0 Gy. The animals were returned to home cages and recovered with no sign of any side effects. The neurogenesis was measured either 1 week or 6 weeks after the irradiation. At 1 week, the number of neuronal progenitors was reduced in a dose-dependent manner with the 50% reduction at 0.78 Gy. The dose–response curve was well fitted by a double exponential suggesting two processes. Examination of the tissue with quantitative immunohistochemistry revealed a dominant low-dose effect on neuronal progenitors resulting in 80% suppression of neurogenesis. This effect was partially reversible, possibly due to compensatory proliferation of the remaining precursors. At higher doses (>5 Gy) there was additional, nearly complete block of neurogenesis without compensatory proliferation. We conclude that notwithstanding the usefulness of irradiation for experimental purposes, the exposure of human subjects to doses often used in radiotherapy treatment could be damaging and cause cognitive impairments. PMID:21541259

  4. A study on laser-based ultrasonic technique by the use of guided wave tomographic imaging

    SciTech Connect

    Park, Junpil Lim, Juyoung; Cho, Younho; Krishnaswamy, Sridhar

    2015-03-31

    Guided wave tests are impractical for investigating specimens with limited accessibility and coarse surfaces or geometrically complicated features. A non-contact setup with a laser ultrasonic transmitter and receiver is the classic attractive for guided wave inspection. The present work was done to develop a non-contact guided-wave tomography technique by laser ultrasonic technique in a plate-like structure. A method for Lam wave generation and detection in an aluminum plate with a pulse laser ultrasonic transmitter and a Michelson interferometer receiver has been developed. In the images obtained by laser scanning, the defect shape and area showed good agreement with the actual defect. The proposed approach can be used as a non-contact-based online inspection and monitoring technique.

  5. Improved accuracy of markerless motion tracking on bone suppression images: preliminary study for image-guided radiation therapy (IGRT)

    NASA Astrophysics Data System (ADS)

    Tanaka, Rie; Sanada, Shigeru; Sakuta, Keita; Kawashima, Hiroki

    2015-05-01

    The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation therapy. We demonstrated the improved accuracy of markerless motion tracking on bone suppression images. Chest fluoroscopic images of nine patients with lung nodules during respiration were obtained using a flat-panel detector system (120 kV, 0.1 mAs/pulse, 5 fps). Commercial bone suppression image processing software was applied to the fluoroscopic images to create corresponding bone suppression images. Regions of interest were manually located on lung nodules and automatic target tracking was conducted based on the template matching technique. To evaluate the accuracy of target tracking, the maximum tracking error in the resulting images was compared with that of conventional fluoroscopic images. The tracking errors were decreased by half in eight of nine cases. The average maximum tracking errors in bone suppression and conventional fluoroscopic images were 1.3   ±   1.0 and 3.3   ±   3.3 mm, respectively. The bone suppression technique was especially effective in the lower lung area where pulmonary vessels, bronchi, and ribs showed complex movements. The bone suppression technique improved tracking accuracy without special equipment and implantation of fiducial markers, and with only additional small dose to the patient. Bone suppression fluoroscopy is a potential measure for respiratory displacement of the target. This paper was presented at RSNA 2013 and was carried out at Kanazawa University, JAPAN.

  6. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder. Final report

    SciTech Connect

    Haines, D.M.; Reinisch, B.W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N{sub e}) as a function of height (the N{sub e} profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year. The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N{sub e} profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al.), has never been put into space. NASA`s 1990 Space Physics Strategy Implementation Study `The NASA Space Physics Program from 1995 to 2010` suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R{sub e} (Reiff et al.; Calvert et al.).

  7. Detection and imaging of atmospheric radio flashes from cosmic ray air showers.

    PubMed

    Falcke, H; Apel, W D; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buitink, S; Brüggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Daumiller, K; de Bruyn, A G; de Vos, C M; Di Pierro, F; Doll, P; Engel, R; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K-H; Kant, G W; Klein, U; Kolotaev, Y; Koopman, Y; Krömer, O; Kuijpers, J; Lafebre, S; Maier, G; Mathes, H J; Mayer, H J; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Pepping, H J; Petcu, M; Petrovic, J; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Schoonderbeek, G; Sima, O; Stümpert, M; Toma, G; Trinchero, G C; Ulrich, H; Valchierotti, S; van Buren, J; van Cappellen, W; Walkowiak, W; Weindl, A; Wijnholds, S; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

    2005-05-19

    The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

  8. Development of an endoscopic fluorescence image-guided OCT probe for oral cancer detection

    NASA Astrophysics Data System (ADS)

    McNichols, Roger J.; Gowda, Ashok; Bell, Brent A.; Johnigan, Richard M.; Calhoun, Karen H.; Motamedi, Massoud

    2001-06-01

    Oral squamous cell carcinoma is a disease which progresses through a number of well-defined morphological and biochemical changes. Optical coherence tomography (OCT) is a rapidly-evolving, non-invasive imaging modality which allows detailed probing of subsurface tissue structures with resolution on the order of microns. While this technique offers tremendous potential as a diagnostic tool for detection and characterization of oral cancer, OCT imaging is presently associated with a field of view on the order of millimeters, and acquisition time on the order of seconds. Thus, OCT's utility as a rapid cancer screening technique is presently limited. On the other hand, imaging of tissue autofluorescence provides a very rapid, high-throughput method for cancer screening. However, while autofluorescence measures may be sensitive to cancer, they are often non- specific and lead to a large number of false positives. In the present work, we have developed a fluorescence image guided optical coherence tomographic (FIG-OCT) probe in which tissue autofluorescence images are simultaneously used to guide OCT image acquisition of suspicious regions in real time. We have begun pre-clinical pilot studies with this instrument in a DMBA-induced model of oral cancer in the hamster cheek pouch. Initial results indicate that the FIG- OCT approach shows promise as a rapid and effective tool for screening of oral cancer.

  9. Precise image-guided irradiation of small animals: a flexible non-profit platform

    NASA Astrophysics Data System (ADS)

    Tillner, Falk; Thute, Prasad; Löck, Steffen; Dietrich, Antje; Fursov, Andriy; Haase, Robert; Lukas, Mathias; Rimarzig, Bernd; Sobiella, Manfred; Krause, Mechthild; Baumann, Michael; Bütof, Rebecca; Enghardt, Wolfgang

    2016-04-01

    Preclinical in vivo studies using small animals are essential to develop new therapeutic options in radiation oncology. Of particular interest are orthotopic tumour models, which better reflect the clinical situation in terms of growth patterns and microenvironmental parameters of the tumour as well as the interplay of tumours with the surrounding normal tissues. Such orthotopic models increase the technical demands and the complexity of preclinical studies as local irradiation with therapeutically relevant doses requires image-guided target localisation and accurate beam application. Moreover, advanced imaging techniques are needed for monitoring treatment outcome. We present a novel small animal image-guided radiation therapy (SAIGRT) system, which allows for precise and accurate, conformal irradiation and x-ray imaging of small animals. High accuracy is achieved by its robust construction, the precise movement of its components and a fast high-resolution flat-panel detector. Field forming and x-ray imaging is accomplished close to the animal resulting in a small penumbra and a high image quality. Feasibility for irradiating orthotopic models has been proven using lung tumour and glioblastoma models in mice. The SAIGRT system provides a flexible, non-profit academic research platform which can be adapted to specific experimental needs and therefore enables systematic preclinical trials in multicentre research networks.

  10. Practical aspects of MR imaging in the presence of conductive guide wires.

    PubMed

    Tong, Natalie; Shmatukha, Andriy; Asmah, Peter; Stainsby, Jeffrey

    2010-01-07

    Various aspects of RF-induced heating of guide wires during their MRI guidance have been investigated in the past. However, the previous works focused on inducing tip heating in either fully immersed or tip-immersed (and otherwise free) wires of impractical lengths in small phantoms. This study simulates real clinical conditions using a product guide wire and a same-length conductive wire partially inserted into a torso-size phantom filled with saline solution. The purpose was to identify potential safety concerns relevant to real clinical applications, as opposed to identifying the worst-case heating scenario. Significant heating occurred at the insertion point, independent of tip heating, with a strong correlation with excitation frequency-dependent imaging parameters. Heat transfer through the wire was also demonstrated to be a safety concern. From these experiments, we have been able to demonstrate additional impacting factors that increase the complexity of safety considerations for the use of conductive guide wires during MR imaging. Safety under a particular set of conditions does not imply safety in all possible conditions that can be encountered during real MRI-guided interventions.

  11. Construction of a conductive distortion reduced electromagnetic tracking system for computer assisted image-guided interventions.

    PubMed

    Li, Mengfei; Bien, Tomasz; Rose, Georg

    2014-11-01

    Alternating current electromagnetic tracking system (EMTS) is widely used in computer-assisted image-guided interventions. However, EMTS suffers from distortions caused by electrically conductive objects in close proximity to tracker tools. Eddy currents in conductive distorters generate secondary magnetic fields that disrupt the measured position and orientation (P&O) of the tracker. This paper proposes a LabVIEW field programmable gate array (FPGA) based EMTS to reduce the interference caused by nearby conductive, but non-ferromagnetic objects upon the method developed in the authors' previous studies. The system's performance was tested in the presence of single/multiple nearby conductive distorters. The results illustrated that the constructed EMTS worked accurately and stably despite nearby static or mobile conductive objects. The technology will allow surgeons to perform image-guided interventions with EMTS even when there are conductive objects close by the tracker tool.

  12. [Image-guided bone consolidation in oncology: Cementoplasty and percutaneous screw fixation].

    PubMed

    Buy, Xavier; Cazzato, Roberto Luigi; Catena, Vittorio; Roubaud, Guilhem; Kind, Michele; Palussiere, Jean

    2017-03-17

    Bone metastases are a common finding in oncology. They often induce pain but also fractures which impair quality of life, especially when involving weight-bearing bones. Percutaneous image-guided consolidation techniques play a major role for the management of bone metastases. Cementoplasty aims to stabilize bone and control pain by injecting acrylic cement into a weakened bone. This minimally invasive technique has proven its efficacy for bones submitted to compression forces: vertebra, acetabular roof, and condyles. However, long bone diaphysis should be treated with caution due to lower resistance of the cement subject to torsional forces. The recent improvements of navigation systems allow percutaneous image-guided screw fixation without requiring open surgery. This fast-track procedure avoids postponing introduction of systemic therapies. If needed, cementoplasty can be combined with screw insertion to ensure better anchoring in major osteolysis. Interventional radiology bone consolidation techniques increase the therapeutic field in oncology. A multidisciplinary approach remains mandatory to select the best indications.

  13. Interrupting Rivaling Access-flow with Nonsurgical Image-guided ligation: the "IRANI" Procedure.

    PubMed

    Cui, Jie; Freed, Robert; Liu, Fengyong; Irani, Zubin

    2015-01-01

    The presence of collateral veins is one of the most common causes of fistula failure to mature. The traditional approach to eliminate collateral vessel flow is coil embolization under fluoroscopy or surgical cut down and branch vessel ligation. However, both approaches are expensive and time consuming. Here, we described an image-guided nonsurgical method to ligate collateral veins. The collateral veins were ligated using Hawkins-Akins needle under ultrasound guidance. The average time for one ligation procedure was 17 minutes. There was a significant increase of blood flow in the venous outflow postligation procedure. Four weeks postprocedure ultrasound demonstrated occlusion of the target vessels. This procedure was well tolerated without major complications. In summary, the novel procedure described here offers an image-guided nonsurgical approach for collateral vein occlusion.

  14. Fluorescence guided lymph node biopsy in large animals using direct image projection device

    NASA Astrophysics Data System (ADS)

    Ringhausen, Elizabeth; Wang, Tylon; Pitts, Jonathan; Akers, Walter J.

    2016-03-01

    The use of fluorescence imaging for aiding oncologic surgery is a fast growing field in biomedical imaging, revolutionizing open and minimally invasive surgery practices. We have designed, constructed, and tested a system for fluorescence image acquisition and direct display on the surgical field for fluorescence guided surgery. The system uses a near-infrared sensitive CMOS camera for image acquisition, a near-infra LED light source for excitation, and DLP digital projector for projection of fluorescence image data onto the operating field in real time. Instrument control was implemented in Matlab for image capture, processing of acquired data and alignment of image parameters with the projected pattern. Accuracy of alignment was evaluated statistically to demonstrate sensitivity to small objects and alignment throughout the imaging field. After verification of accurate alignment, feasibility for clinical application was demonstrated in large animal models of sentinel lymph node biopsy. Indocyanine green was injected subcutaneously in Yorkshire pigs at various locations to model sentinel lymph node biopsy in gynecologic cancers, head and neck cancer, and melanoma. Fluorescence was detected by the camera system during operations and projected onto the imaging field, accurately identifying tissues containing the fluorescent tracer at up to 15 frames per second. Fluorescence information was projected as binary green regions after thresholding and denoising raw intensity data. Promising results with this initial clinical scale prototype provided encouraging results for the feasibility of optical projection of acquired luminescence during open oncologic surgeries.

  15. High-resolution mini gamma camera for diagnosis and radio-guided surgery in diabetic foot infection

    NASA Astrophysics Data System (ADS)

    Scopinaro, F.; Capriotti, G.; Di Santo, G.; Capotondi, C.; Micarelli, A.; Massari, R.; Trotta, C.; Soluri, A.

    2006-12-01

    The diagnosis of diabetic foot osteomyelitis is often difficult. 99mTc-WBC (White Blood Cell) scintigraphy plays a key role in the diagnosis of bone infections. Spatial resolution of Anger camera is not always able to differentiate soft tissue from bone infection. Aim of present study is to verify if HRD (High-Resolution Detector) is able to improve diagnosis and to help surgery. Patients were studied by HRD showing 25.7×25.7 mm 2 FOV, 2 mm spatial resolution and 18% energy resolution. The patients were underwent to surgery and, when necessary, bone biopsy, both guided by HRD. Four patients were positive at Anger camera without specific signs of osteomyelitis. HRS (High-Resolution Scintigraphy) showed hot spots in the same patients. In two of them the hot spot was bar-shaped and it was localized in correspondence of the small phalanx. The presence of bone infection was confirmed at surgery, which was successfully guided by HRS. 99mTc-WBC HRS was able to diagnose pedal infection and to guide the surgery of diabetic foot, opening a new way in the treatment of infected diabetic foot.

  16. Image-guided thermal therapy with a dual-contrast magnetic nanoparticle formulation: A feasibility study

    PubMed Central

    Attaluri, Anilchandra; Seshadri, Madhav; Mirpour, Sahar; Wabler, Michele; Marinho, Thomas; Furqan, Muhammad; Zhou, Haoming; De Paoli, Silvia; Gruettner, Cordula; Gilson, Wesley; DeWeese, Theodore; Garcia, Monica; Ivkov, Robert; Liapi, Eleni

    2016-01-01

    Purpose/objective The aim of this study was to develop and investigate the properties of a magnetic iron oxide nanoparticle–ethiodised oil formulation for image-guided thermal therapy of liver cancer. Materials and methods The formulation comprises bionised nano-ferrite (BNF) nanoparticles suspended in ethiodised oil, emulsified with polysorbate 20 (BNF-lip). Nanoparticle size was measured via photon correlation spectroscopy and transmission electron microscopy. In vivo thermal therapy capability was tested in two groups of male Foxn1nu mice bearing subcutaneous HepG2 xenograft tumours. Group I (n =12) was used to screen conditions for group II (n =48). In group II, mice received one of BNF-lip (n =18), BNF alone (n =16), or PBS (n =14), followed by alternating magnetic field (AMF) hyperthermia, with either varied duration (15 or 20 min) or amplitude (0, 16, 20, or 24 kA/m). Image-guided fluoroscopic intra-arterial injection of BNF-lip was tested in New Zealand white rabbits (n =10), bearing liver VX2 tumours. The animals were subsequently imaged with CT and 3 T MRI, up to 7 days post-injection. The tumours were histopathologically evaluated for distribution of BNF-lip. Results The BNF showed larger aggregate diameters when suspended in BNF-lip, compared to clear solution. The BNF-lip formulation produced maximum tumour temperatures with AMF >20 kA/m and showed positive X-ray visibility and substantial shortening of T1 and T2 relaxation time, with sustained intratumoural retention up to 7 days post-injection. On pathology, intratumoural BNF-lip distribution correlated well with CT imaging of intratumoural BNF-lip distribution. Conclusion The BNF-lip formulation has favourable thermal and dual imaging capabilities for image-guided thermal therapy of liver cancer, suggesting further exploration for clinical applications. PMID:27151045

  17. The accuracy and efficacy of palpation versus image-guided peripheral injections in sports medicine.

    PubMed

    Hall, Mederic M

    2013-01-01

    There is much debate in the sports medicine community regarding the need for image guidance during peripheral joint and soft tissue injections. With the increasing availability of office-based ultrasound, many injections that were performed previously with a palpation-guided technique are being performed now under direct sonographic guidance. However some question the need for such guidance, particularly given the increased cost. This manuscript will review the reported accuracy and efficacy for various injections commonly performed in a sports medicine practice.

  18. [Image guided and robotic treatment--the advance of cybernetics in clinical medicine].

    PubMed

    Fosse, E; Elle, O J; Samset, E; Johansen, M; Røtnes, J S; Tønnessen, T I; Edwin, B

    2000-01-10

    The introduction of advanced technology in hospitals has changed the treatment practice towards more image guided and minimal invasive procedures. Modern computer and communication technology opens up for robot aided and pre-programmed intervention. Several robotic systems are in clinical use today both in microsurgery and in major cardiac and orthopedic operations. As this trend develops, professions which are new in this context such as physicists, mathematicians and cybernetic engineers will be increasingly important in the treatment of patients.

  19. Post-Prostatectomy Image-Guided Radiotherapy: The Invisible Target Concept

    PubMed Central

    Vilotte, Florent; Antoine, Mickael; Bobin, Maxime; Latorzeff, Igor; Supiot, Stéphane; Richaud, Pierre; Thomas, Laurence; Leduc, Nicolas; Guérif, Stephane; Iriondo-Alberdi, Jone; de Crevoisier, Renaud; Sargos, Paul

    2017-01-01

    In the era of intensity-modulated radiation therapy, image-guided radiotherapy (IGRT) appears crucial to control dose delivery and to promote dose escalation while allowing healthy tissue sparing. The place of IGRT following radical prostatectomy is poorly described in the literature. This review aims to highlight some key points on the different IGRT techniques applicable to prostatic bed radiotherapy. Furthermore, methods used to evaluate target motion and to reduce planning target volume margins will also be explored. PMID:28337425

  20. Post-Prostatectomy Image-Guided Radiotherapy: The Invisible Target Concept.

    PubMed

    Vilotte, Florent; Antoine, Mickael; Bobin, Maxime; Latorzeff, Igor; Supiot, Stéphane; Richaud, Pierre; Thomas, Laurence; Leduc, Nicolas; Guérif, Stephane; Iriondo-Alberdi, Jone; de Crevoisier, Renaud; Sargos, Paul

    2017-01-01

    In the era of intensity-modulated radiation therapy, image-guided radiotherapy (IGRT) appears crucial to control dose delivery and to promote dose escalation while allowing healthy tissue sparing. The place of IGRT following radical prostatectomy is poorly described in the literature. This review aims to highlight some key points on the different IGRT techniques applicable to prostatic bed radiotherapy. Furthermore, methods used to evaluate target motion and to reduce planning target volume margins will also be explored.

  1. Development of an integral system test for image-guided radiotherapy

    SciTech Connect

    Rowbottom, Carl G.; Jaffray, David A.

    2004-12-01

    An integral system test was developed to determine the precision and accuracy of an image-guided radiotherapy system involving an x-ray volumetric imaging device mounted onto the gantry of a medical linear accelerator. The test was designed to interrogate the system components as a whole without deconstructing the individual sources of error. The integral system test was based on the imaging of an unambiguous stationary object in the treatment position and so took no account of patient related errors. An array of micromosfets interspersed within slices of a tissue equivalent phantom was developed as an imaging test object. It has previously been demonstrated that micromosfets have a very small active volume, are clearly visible on CT images, and produce no significant artifacts. In addition, the active volume of the micromosfets can be accurately inferred radiographically via the use of x-ray volumetric imaging. X-ray volumetric imaging was performed with the object in the treatment position, then reconstructed and transferred to a treatment planning system. With the phantom remaining undisturbed in the treatment position a series of treatment fields were designed to produce a series of fields with the leaf edge sweeping across active volume of the micromosfets. The fields were delivered with a micro-MLC to dosimetrically verify the position of the mosfets and compare with dose values produced by the treatment planning system. It was demonstrated that the systematic gantry flex could be accounted for by the imaging and delivery systems. For the delivery system small changes in leaf positions of the micro-MLC were required to account for gantry flex. The position of the micromosfets determined by the 50% dose position was on average (0.15{+-}0.13) mm away from the position determined radiographically for the x and y axes, and (1.0{+-}0.14) mm for the z axis. This implies that a margin of approximately 0.2 mm in the axial plane and 1.0 mm in the superior

  2. Nuclear medical imaging using β+γ coincidences from 44Sc radio-nuclide with liquid xenon as detection medium

    NASA Astrophysics Data System (ADS)

    Grignon, C.; Barbet, J.; Bardiès, M.; Carlier, T.; Chatal, J. F.; Couturier, O.; Cussonneau, J. P.; Faivre, A.; Ferrer, L.; Girault, S.; Haruyama, T.; Le Ray, P.; Luquin, L.; Lupone, S.; Métivier, V.; Morteau, E.; Servagent, N.; Thers, D.

    2007-02-01

    We report on a new nuclear medical imaging technique based on the measurement of the emitter location in the three dimensions with a few mm spatial resolution using β+γ emitters. Such measurement could be realized thanks to a new kind of radio-nuclides which emit a γ-ray quasi-simultaneously with the β+ decay. The most interesting radio-nuclide candidate, namely 44Sc, will be potentially produced at the Nantes cyclotron ARRONAX. The principle is to reconstruct the intersection of the classical line of response (obtained with a standard PET camera) with the direction cone defined by the third γ-ray. The emission angle measurement of this additional γ-ray involves the use of a Compton telescope for which a new generation of camera based on a liquid xenon (LXe) time projection chamber is considered. GEANT3 simulations of a large acceptance LXe Compton telescope combined with a commercial micro-PET (LSO crystals) have been performed and the obtained results will be presented. They demonstrate that a good image can be obtained from the accumulation of each three-dimensional measured position. A spatial resolution of 2.3 mm has been reached with an injected activity of 0.5 MBq for a 44Sc point source emitter.

  3. High Power, Computer-Controlled, LED-Based Light Sources for Fluorescence Imaging and Image-Guided Surgery

    PubMed Central

    Gioux, Sylvain; Kianzad, Vida; Ciocan, Razvan; Gupta, Sunil; Oketokoun, Rafiou; Frangioni, John V.

    2009-01-01

    Optical imaging requires appropriate light sources. For image-guided surgery, and in particular fluorescence-guided surgery, high fluence rate, long working distance, computer control, and precise control of wavelength are required. In this study, we describe the development of light emitting diode (LED)-based light sources that meet these criteria. These light sources are enabled by a compact LED module that includes an integrated linear driver, heat-dissipation technology, and real-time temperature monitoring. Measuring only 27 mm W by 29 mm H, and weighing only 14.7 g, each module provides up to 6500 lx of white (400-650 nm) light and up to 157 mW of filtered fluorescence excitation light, while maintaining an operating temperature ≤ 50°C. We also describe software that can be used to design multi-module light housings, and an embedded processor that permits computer control and temperature monitoring. With these tools, we constructed a 76-module, sterilizable, 3-wavelength surgical light source capable of providing up to 40,000 lx of white light, 4.0 mW/cm2 of 670 nm near-infrared (NIR) fluorescence excitation light, and 14.0 mW/cm2 of 760 nm NIR fluorescence excitation light over a 15-cm diameter field-of-view. Using this light source, we demonstrate NIR fluorescence-guided surgery in a large animal model. PMID:19723473

  4. SU-E-I-39: Molecular Image Guided Cancer Stem Cells Therapy

    SciTech Connect

    Abdollahi, H

    2014-06-01

    Purpose: Cancer stem cells resistance to radiation is a problematic issue that has caused a big fail in cancer treatment. Methods: As a primary work, molecular imaging can indicate the main mechanisms of radiation resistance of cancer stem cells. By developing and commissioning new probes and nanomolecules and biomarkers, radiation scientist will able to identify the essential pathways of radiation resistance of cancer stem cells. As the second solution, molecular imaging is a best way to find biological target volume and delineate cancer stem cell tissues. In the other hand, by molecular imaging techniques one can image the treatment response in tumor and also in normal tissue. In this issue, the response of cancer stem cells to radiation during therapy course can be imaged, also the main mechanisms of radiation resistance and finding the best radiation modifiers (sensitizers) can be achieved by molecular imaging modalities. In adaptive radiotherapy the molecular imaging plays a vital role to have higher tumor control probability by delivering high radiation doses to cancer stem cells in any time of treatment. The outcome of a feasible treatment is dependent to high cancer stem cells response to radiation and removing all of which, so a good imaging modality can show this issue and preventing of tumor recurrence and metastasis. Results: Our results are dependent to use of molecular imaging as a new modality in the clinic. We propose molecular imaging as a new radiobiological technique to solve radiation therapy problems due to cancer stem cells. Conclusion: Molecular imaging guided cancer stem cell diagnosis and therapy is a new approach in the field of cancer treatment. This new radiobiological imaging technique should be developed in all clinics as a feasible tool that is more biological than physical imaging.

  5. Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation

    NASA Astrophysics Data System (ADS)

    Yang, Yidong; Armour, Michael; Kang-Hsin Wang, Ken; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

    2015-07-01

    The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal (‘tubular’ geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal (‘pancake’ geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry

  6. Evaluation of a Cone Beam Computed Tomography Geometry for Image Guided Small Animal Irradiation

    PubMed Central

    Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

    2015-01-01

    The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal (“tubular” geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal (“pancake” geometry). The small animal radiation research platform (SARRP) developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Notwithstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e., pancake and tubular geometry

  7. Evaluation of a cone beam computed tomography geometry for image guided small animal irradiation.

    PubMed

    Yang, Yidong; Armour, Michael; Wang, Ken Kang-Hsin; Gandhi, Nishant; Iordachita, Iulian; Siewerdsen, Jeffrey; Wong, John

    2015-07-07

    The conventional imaging geometry for small animal cone beam computed tomography (CBCT) is that a detector panel rotates around the head-to-tail axis of an imaged animal ('tubular' geometry). Another unusual but possible imaging geometry is that the detector panel rotates around the anterior-to-posterior axis of the animal ('pancake' geometry). The small animal radiation research platform developed at Johns Hopkins University employs the pancake geometry where a prone-positioned animal is rotated horizontally between an x-ray source and detector panel. This study is to assess the CBCT image quality in the pancake geometry and investigate potential methods for improvement. We compared CBCT images acquired in the pancake geometry with those acquired in the tubular geometry when the phantom/animal was placed upright simulating the conventional CBCT geometry. Results showed signal-to-noise and contrast-to-noise ratios in the pancake geometry were reduced in comparison to the tubular geometry at the same dose level. But the overall spatial resolution within the transverse plane of the imaged cylinder/animal was better in the pancake geometry. A modest exposure increase to two folds in the pancake geometry can improve image quality to a level close to the tubular geometry. Image quality can also be improved by inclining the animal, which reduces streak artifacts caused by bony structures. The major factor resulting in the inferior image quality in the pancake geometry is the elevated beam attenuation along the long axis of the phantom/animal and consequently increased scatter-to-primary ratio in that orientation. Not withstanding, the image quality in the pancake-geometry CBCT is adequate to support image guided animal positioning, while providing unique advantages of non-coplanar and multiple mice irradiation. This study also provides useful knowledge about the image quality in the two very different imaging geometries, i.e. pancake and tubular geometry, respectively.

  8. Computational Modeling for Enhancing Soft Tissue Image Guided Surgery: An Application in Neurosurgery

    PubMed Central

    Miga, Michael I.

    2016-01-01

    With the recent advances in computing, the opportunities to translate computational models to more integrated roles in patient treatment are expanding at an exciting rate. One area of considerable development has been directed towards correcting soft tissue deformation within image guided neurosurgery applications. This review captures the efforts that have been undertaken towards enhancing neuronavigation by the integration of soft tissue biomechanical models, imaging and sensing technologies, and algorithmic developments. In addition, the review speaks to the evolving role of modeling frameworks within surgery and concludes with some future directions beyond neurosurgical applications. PMID:26354118

  9. Development of a Meso-Scale SMA-Based Torsion Actuator for Image-Guided Procedures.

    PubMed

    Sheng, Jun; Gandhi, Dheeraj; Gullapalli, Rao; Simard, J Marc; Desai, Jaydev P

    2017-02-01

    This paper presents the design, modeling, and control of a meso-scale torsion actuator based on shape memory alloy (SMA) for image-guided surgical procedures. Developing a miniature torsion actuator is challenging, but it opens the possibility of significantly enhancing the robot agility and maneuverability. The proposed torsion actuator is bi-directionally actuated by a pair of antagonistic SMA torsion springs through alternate Joule heating and natural cooling. The torsion actuator is integrated into a surgical robot prototype to demonstrate its working performance in the humid environment under C-Arm CT image guidance.

  10. Image-guided surgery using near-infrared fluorescent light: from bench to bedside

    NASA Astrophysics Data System (ADS)

    Boogerd, Leonora S. F.; Handgraaf, Henricus J. M.; van de Velde, Cornelis J. H.; Vahrmeijer, Alexander L.

    2015-03-01

    Due to its relatively high tissue penetration, near-infrared (NIR; 700-900 nm) fluorescent light has the potential to visualize structures that need to be resected (e.g. tumors, lymph nodes) and structures that need to be spared (e.g. nerves, ureters, bile ducts). Until now, most clinical trials have focused on suboptimal, non-targeted dyes. Although successful, a new era in image-guided surgery has begun by the introduction of tumor-targeted agents. In this paper, we will describe how tumor-targeted NIR fluorescent imaging can be applied in a clinical setting.

  11. Percutaneous inner-ear access via an image-guided industrial robot system

    PubMed Central

    Baron, S; Eilers, H; Munske, B; Toennies, JL; Balachandran, R; Labadie, RF; Ortmaier, T; Webster, RJ

    2014-01-01

    Image-guided robots have been widely used for bone shaping and percutaneous access to interventional sites. However, due to high-accuracy requirements and proximity to sensitive nerves and brain tissues, the adoption of robots in inner-ear surgery has been slower. In this paper the authors present their recent work towards developing two image-guided industrial robot systems for accessing challenging inner-ear targets. Features of the systems include optical tracking of the robot base and tool relative to the patient and Kalman filter-based data fusion of redundant sensory information (from encoders and optical tracking systems) for enhanced patient safety. The approach enables control of differential robot positions rather than absolute positions, permitting simplified calibration procedures and reducing the reliance of the system on robot calibration in order to ensure overall accuracy. Lastly, the authors present the results of two phantom validation experiments simulating the use of image-guided robots in inner-ear surgeries such as cochlear implantation and petrous apex access. PMID:20718268

  12. Percutaneous inner-ear access via an image-guided industrial robot system.

    PubMed

    Baron, S; Eilers, H; Munske, B; Toennies, J L; Balachandran, R; Labadie, R F; Ortmaier, T; Webster, R J

    2010-01-01

    Image-guided robots have been widely used for bone shaping and percutaneous access to interventional sites. However, due to high-accuracy requirements and proximity to sensitive nerves and brain tissues, the adoption of robots in inner-ear surgery has been slower. In this paper the authors present their recent work towards developing two image-guided industrial robot systems for accessing challenging inner-ear targets. Features of the systems include optical tracking of the robot base and tool relative to the patient and Kalman filter-based data fusion of redundant sensory information (from encoders and optical tracking systems) for enhanced patient safety. The approach enables control of differential robot positions rather than absolute positions, permitting simplified calibration procedures and reducing the reliance of the system on robot calibration in order to ensure overall accuracy. Lastly, the authors present the results of two phantom validation experiments simulating the use of image-guided robots in inner-ear surgeries such as cochlear implantation and petrous apex access.

  13. Image-Guided Drug Delivery with Single-Photon Emission Computed Tomography: A Review of Literature

    PubMed Central

    Chakravarty, Rubel; Hong, Hao; Cai, Weibo

    2014-01-01

    Tremendous resources are being invested all over the world for prevention, diagnosis, and treatment of various types of cancer. Successful cancer management depends on accurate diagnosis of the disease along with precise therapeutic protocol. The conventional systemic drug delivery approaches generally cannot completely remove the competent cancer cells without surpassing the toxicity limits to normal tissues. Therefore, development of efficient drug delivery systems holds prime importance in medicine and healthcare. Also, molecular imaging can play an increasingly important and revolutionizing role in disease management. Synergistic use of molecular imaging and targeted drug delivery approaches provides unique opportunities in a relatively new area called `image-guided drug delivery' (IGDD). Single-photon emission computed tomography (SPECT) is the most widely used nuclear imaging modality in clinical context and is increasingly being used to guide targeted therapeutics. The innovations in material science have fueled the development of efficient drug carriers based on, polymers, liposomes, micelles, dendrimers, microparticles, nanoparticles, etc. Efficient utilization of these drug carriers along with SPECT imaging technology have the potential to transform patient care by personalizing therapy to the individual patient, lessening the invasiveness of conventional treatment procedures and rapidly monitoring the therapeutic efficacy. SPECT-IGDD is not only effective for treatment of cancer but might also find utility in management of several other diseases. Herein, we provide a concise overview of the latest advances in SPECT-IGDD procedures and discuss the challenges and opportunities for advancement of the field. PMID:25182469

  14. pH-Triggered Polypeptides Nanoparticles for Efficient BODIPY Imaging-Guided Near Infrared Photodynamic Therapy.

    PubMed

    Liu, Le; Fu, Liyi; Jing, Titao; Ruan, Zheng; Yan, Lifeng

    2016-04-13

    An efficient pH-responsive multifunctional polypeptide micelle for simultaneous imaging and in vitro photodynamic therapy (PDT) has been prepared. The goal here is to detect and treat cancer cells by near-infrared fluorescence (NIRF) imaging and PDT synchronously. A photosensitizer BODIPY-Br2 with efficient singlet oxygen generation was synthesized at first which owns both seductive abilities in fluorescence emission and reactive oxygen species (ROS) generation under light irradiation. Then, amphiphilic copolymer micelles pH-triggered disassembly were synthesized from N-carboxyanhydride (NCA) monomer via a ring-opening polymerization and click reaction for the loading of BODIPY-Br2 by hydrophobic interaction, and the driving force is the protonation of the diisopropylethylamine groups conjugated to the polypeptide side chains. In vitro tests performed on HepG2 cancer cells confirm that the cell suppression rate was improved by more than 40% in the presence of light in the presence of an extremely low energy density (12 J/cm(2)) with very low concentration of 5.4 μM photosensitizer. At the same time, the internalization of the nanoparticles by cells can also be traced by NIRF imaging, indicating that the NIR nanoparticles presented imaging guided photodynamic therapy properties. It provides the potential of using polypeptide as a biodegradable carrier for NIR image-guided photodynamic therapy.

  15. Speckle filtering of medical ultrasonic images using wavelet and guided filter.

    PubMed

    Zhang, Ju; Lin, Guangkuo; Wu, Lili; Cheng, Yun

    2016-02-01

    Speckle noise is an inherent yet ineffectual residual artifact in medical ultrasound images, which significantly degrades quality and restricts accuracy in automatic diagnostic techniques. Speckle reduction is therefore an important step prior to the analysis and processing of the ultrasound images. A new de-noising method based on an improved wavelet filter and guided filter is proposed in this paper. According to the characteristics of medical ultrasound images in the wavelet domain, an improved threshold function based on the universal wavelet threshold function is developed. The wavelet coefficients of speckle noise and noise-free signal are modeled as Rayleigh distribution and generalized Gaussian distribution respectively. The Bayesian maximum a posteriori estimation is applied to obtain a new wavelet shrinkage algorithm. The coefficients of the low frequency sub-band in the wavelet domain are filtered by guided filter. The filtered image is then obtained by using the inverse wavelet transformation. Experiments with the comparison of the other seven de-speckling filters are conducted. The results show that the proposed method not only has a strong de-speckling ability, but also keeps the image details, such as the edge of a lesion.

  16. 700 nm Zwitterionic Near-Infrared Fluorophores for Dual-Channel Image-Guided Surgery

    PubMed Central

    Hyun, Hoon; Henary, Maged; Gao, Tielong; Narayana, Lakshminarayana; Owens, Eric A.; Lee, Jeong Heon; Park, GwangLi; Wada, Hideyuki; Ashitate, Yoshitomo; Frangioni, John V.; Choi, Hak Soo

    2015-01-01

    Purpose To develop a family of 700 nm zwitterionic pentamethine indocyanine near-infrared fluorophores that would permit dual-channel image-guided surgery. Procedures Three complementary synthetic schemes were used to produce novel zwitterionic chemical structures. Physicochemical, optical, biodistribution, and clearance properties were compared to Cy5.5, a conventional pentamethine indocyanine now used for biomedical imaging. Results ZW700-1a, ZW700-1b, and ZW700-1c were synthesized, purified, and analyzed extensively in vitro and in vivo. All molecules had extinction coefficients ≥ 199,000 M−1cm−1, emission ≥ 660 nm, and stability ≥ 99% after 24 h in warm serum. In mice, rats, and pigs, ≥ 80% of the injected dose was completely eliminated from the body via renal clearance within 4 h. Either alone or conjugated to a tumor targeting ligand, ZW700-1a permitted dual-channel, high SBR, and simultaneous imaging with 800 nm NIR fluorophores using the FLARE® imaging system. Conclusions Novel 700 nm zwitterionic NIR fluorophores enable dual-NIR image-guided surgery. PMID:26084246

  17. OpenIGTLink: an open network protocol for image-guided therapy environment

    PubMed Central

    Tokuda, Junichi; Fischer, Gregory S.; Papademetris, Xenophon; Yaniv, Ziv; Ibanez, Luis; Cheng, Patrick; Liu, Haiying; Blevins, Jack; Arata, Jumpei; Golby, Alexandra J.; Kapur, Tina; Pieper, Steve; Burdette, Everette C.; Fichtinger, Gabor; Tempany, Clare M.; Hata, Nobuhiko

    2009-01-01

    Background With increasing research on system integration for image-guided therapy (IGT), there has been a strong demand for standardized communication among devices and software to share data such as target positions, images and device status. Method We propose a new, open, simple and extensible network communication protocol for IGT, named OpenIGTLink, to transfer transform, image and status messages. We conducted performance tests and use-case evaluations in five clinical and engineering scenarios. Results The protocol was able to transfer position data with submillisecond latency up to 1024 fps and images with latency of <10 ms at 32 fps. The use-case tests demonstrated that the protocol is feasible for integrating devices and software. Conclusion The protocol proved capable of handling data required in the IGT setting with sufficient time resolution and latency. The protocol not only improves the interoperability of devices and software but also promotes transitions of research prototypes to clinical applications.. PMID:19621334

  18. Next generation NIR fluorophores for tumor imaging and fluorescence-guided surgery: A review.

    PubMed

    Haque, Ashanul; Faizi, Md Serajul Haque; Rather, Jahangir Ahmad; Khan, Muhammad S

    2017-04-01

    Cancer is a group of diseases responsible for the major causes of mortality and morbidity among people of all ages. Even though medical sciences have made enormous growth, complete treatment of this deadly disease is still a challenging task. Last few decades witnessed an impressive growth in the design and development of near infrared (NIR) fluorophores with and without recognition moieties for molecular recognitions, imaging and image guided surgeries. The present article reviews recently reported NIR emitting organic/inorganic fluorophores that targets and accumulates in organelle/organs specifically for molecular imaging of cancerous cells. Near infrared (NIR probe) with or without a tumor-targeting warhead have been considered and discussed for their applications in the field of cancer imaging. In addition, challenges persist in this area are also delineated in this review.

  19. Multiple Active Contours Guided by Differential Evolution for Medical Image Segmentation

    PubMed Central

    Cruz-Aceves, I.; Avina-Cervantes, J. G.; Lopez-Hernandez, J. M.; Rostro-Gonzalez, H.; Garcia-Capulin, C. H.; Torres-Cisneros, M.; Guzman-Cabrera, R.

    2013-01-01

    This paper presents a new image segmentation method based on multiple active contours guided by differential evolution, called MACDE. The segmentation method uses differential evolution over a polar coordinate system to increase the exploration and exploitation capabilities regarding the classical active contour model. To evaluate the performance of the proposed method, a set of synthetic images with complex objects, Gaussian noise, and deep concavities is introduced. Subsequently, MACDE is applied on datasets of sequential computed tomography and magnetic resonance images which contain the human heart and the human left ventricle, respectively. Finally, to obtain a quantitative and qualitative evaluation of the medical image segmentations compared to regions outlined by experts, a set of distance and similarity metrics has been adopted. According to the experimental results, MACDE outperforms the classical active contour model and the interactive Tseng method in terms of efficiency and robustness for obtaining the optimal control points and attains a high accuracy segmentation. PMID:23983809

  20. Molecular imaging as a guide for the treatment of central nervous system disorders.

    PubMed

    Kim, Euitae; Howes, Oliver D; Kapur, Shitij

    2013-09-01

    Molecular imaging techniques have a number of advantages for research into the pathophysiology and treatment of central nervous system (CNS) disorders. Firstly, they provide a noninvasive means of characterizing physiological processes in the living brain, enabling molecular alterations to be linked to clinical changes. Secondly, the pathophysiological target in a given CNS disorder can be measured in animal models and in experimental human models in the same way, which enables translational research. Moreover, as molecular imaging facilitates the detection of functional change which precedes gross pathology, it is particularly useful for the early diagnosis and treatment of CNS disorders. This review considers the application of molecular imaging to CNS disorders focusing on its potential to inform the development and evaluation of treatments. We focus on schizophrenia, Parkinson's disease, depression, and dementia as major CNS disorders. We also review the potential of molecular imaging to guide new drug development for CNS disorders.

  1. Imaging osteoarthritis in the knee joints using x-ray guided diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Qizhi; Yuan, Zhen; Sobel, Eric S.; Jiang, Huabei

    2010-02-01

    In our previous studies, near-infrared (NIR) diffuse optical tomography (DOT) had been successfully applied to imaging osteoarthritis (OA) in the finger joints where significant difference in optical properties of the joint tissues was evident between healthy and OA finger joints. Here we report for the first time that large joints such as the knee can also be optically imaged especially when DOT is combined with x-ray tomosynthesis where the 3D image of the bones from x-ray is incorporated into the DOT reconstruction as spatial a priori structural information. This study demonstrates that NIR light can image large joints such as the knee in addition to finger joints, which will drastically broaden the clinical utility of our x-ray guided DOT technique for OA diagnosis.

  2. An image-intensive ePR for image-guided minimally invasive spine surgery applications including real-time intra-operative image acquisition, archival, and display

    NASA Astrophysics Data System (ADS)

    Documet, Jorge R.; Le, Anh; Liu, Brent; Huang, H. K.; Chiu, John

    2009-02-01

    Recent developments in medical imaging informatics have improved clinical workflow in Radiology enterprise but gaps remain in the clinical workflow from diagnosis to surgical treatment through post-operative follow-up. One solution to bridge this gap is the development of an electronic patient record (ePR) that integrates key imaging and informatics data during the pre, intra, and post-operative phases of clinical workflow. We present an ePR system based on standards and tailored to the clinical application for image-guided minimally invasive spinal surgery (MISS). The ePR system has been implemented in a clinical environment for a half-year.

  3. Image-guided intervention in the human bile duct using scanning fiber endoscope system

    NASA Astrophysics Data System (ADS)

    Seibel, Eric J.; Jo, Javier A.; Melville, C. David; Johnston, Richard S.; Naumann, Christopher R.; Saunders, Michael D.

    2012-01-01

    Bile duct cancers are increasing in frequency while being difficult to diagnose. Currently available endoscopic imaging devices used in the biliary tree are low resolution with poor image quality, leading to inadequate evaluation of indeterminate biliary strictures. However, a new ultrathin and flexible cholangioscope system has been successfully demonstrated in a human subject. This mini-cholangioscope system uses a scanning fiber endoscope (SFE) as a forward-imaging guidewire, dimensions of 1.2-mm diameter and 3-m length. Full color video (500-line resolution at 30Hz) is the standard SFE imaging mode using spiral scanning of red, green, and blue laser light at low power. Image-guided operation of the biopsy forceps was demonstrated in healthy human bile ducts with and without saline flushing. The laser-based video imaging can be switched to various modes to enhance tissue markers of disease, such as widefield fluorescence and enhanced spectral imaging. In parallel work, biochemical discrimination of tissue health in pig bile duct has been accomplished using fiberoptic delivery of pulsed UV illumination and time-resolved autofluorescence spectroscopic measurements. Implementation of time-resolved fluorescence spectroscopy for biochemical assessment of the bile duct wall is being done through a secondary endoscopic channel. Preliminary results indicate that adequate SNR levels (> 30 dB) can be achieved through a 50 micron fiber, which could serve as an optical biopsy probe. The SFE is an ideal mini-cholangioscope for integration of both tissue and molecular specific image contrast in the future. This will provide the physician with unprecedented abilities to target biopsy locations and perform endoscopically-guided therapies.

  4. Designing a wearable navigation system for image-guided cancer resection surgery.

    PubMed

    Shao, Pengfei; Ding, Houzhu; Wang, Jinkun; Liu, Peng; Ling, Qiang; Chen, Jiayu; Xu, Junbin; Zhang, Shiwu; Xu, Ronald

    2014-11-01

    A wearable surgical navigation system is developed for intraoperative imaging of surgical margin in cancer resection surgery. The system consists of an excitation light source, a monochromatic CCD camera, a host computer, and a wearable headset unit in either of the following two modes: head-mounted display (HMD) and Google glass. In the HMD mode, a CMOS camera is installed on a personal cinema system to capture the surgical scene in real-time and transmit the image to the host computer through a USB port. In the Google glass mode, a wireless connection is established between the glass and the host computer for image acquisition and data transport tasks. A software program is written in Python to call OpenCV functions for image calibration, co-registration, fusion, and display with augmented reality. The imaging performance of the surgical navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex vivo tissue model. Surgical margins identified by the wearable navigation system are co-incident with those acquired by a standard small animal imaging system, indicating the technical feasibility for intraoperative surgical margin detection. The proposed surgical navigation system combines the sensitivity and specificity of a fluorescence imaging system and the mobility of a wearable goggle. It can be potentially used by a surgeon to identify the residual tumor foci and reduce the risk of recurrent diseases without interfering with the regular resection procedure.

  5. Semantic and topological classification of images in magnetically guided capsule endoscopy

    NASA Astrophysics Data System (ADS)

    Mewes, P. W.; Rennert, P.; Juloski, A. L.; Lalande, A.; Angelopoulou, E.; Kuth, R.; Hornegger, J.

    2012-03-01

    Magnetically-guided capsule endoscopy (MGCE) is a nascent technology with the goal to allow the steering of a capsule endoscope inside a water filled stomach through an external magnetic field. We developed a classification cascade for MGCE images with groups images in semantic and topological categories. Results can be used in a post-procedure review or as a starting point for algorithms classifying pathologies. The first semantic classification step discards over-/under-exposed images as well as images with a large amount of debris. The second topological classification step groups images with respect to their position in the upper gastrointestinal tract (mouth, esophagus, stomach, duodenum). In the third stage two parallel classifications steps distinguish topologically different regions inside the stomach (cardia, fundus, pylorus, antrum, peristaltic view). For image classification, global image features and local texture features were applied and their performance was evaluated. We show that the third classification step can be improved by a bubble and debris segmentation because it limits feature extraction to discriminative areas only. We also investigated the impact of segmenting intestinal folds on the identification of different semantic camera positions. The results of classifications with a support-vector-machine show the significance of color histogram features for the classification of corrupted images (97%). Features extracted from intestinal fold segmentation lead only to a minor improvement (3%) in discriminating different camera positions.

  6. Crack Imaging and Quantification in Aluminum Plates with Guided Wave Wavenumber Analysis Methods

    NASA Technical Reports Server (NTRS)

    Yu, Lingyu; Tian, Zhenhua; Leckey, Cara A. C.

    2015-01-01

    Guided wavefield analysis methods for detection and quantification of crack damage in an aluminum plate are presented in this paper. New wavenumber components created by abrupt wave changes at the structural discontinuity are identified in the frequency-wavenumber spectra. It is shown that the new wavenumbers can be used to detect and characterize the crack dimensions. Two imaging based approaches, filter reconstructed imaging and spatial wavenumber imaging, are used to demonstrate how the cracks can be evaluated with wavenumber analysis. The filter reconstructed imaging is shown to be a rapid method to map the plate and any existing damage, but with less precision in estimating crack dimensions; while the spatial wavenumber imaging provides an intensity image of spatial wavenumber values with enhanced resolution of crack dimensions. These techniques are applied to simulated wavefield data, and the simulation based studies show that spatial wavenumber imaging method is able to distinguish cracks of different severities. Laboratory experimental validation is performed for a single crack case to confirm the methods' capabilities for imaging cracks in plates.

  7. Designing a wearable navigation system for image-guided cancer resection surgery

    PubMed Central

    Shao, Pengfei; Ding, Houzhu; Wang, Jinkun; Liu, Peng; Ling, Qiang; Chen, Jiayu; Xu, Junbin; Zhang, Shiwu; Xu, Ronald

    2015-01-01

    A wearable surgical navigation system is developed for intraoperative imaging of surgical margin in cancer resection surgery. The system consists of an excitation light source, a monochromatic CCD camera, a host computer, and a wearable headset unit in either of the following two modes: head-mounted display (HMD) and Google glass. In the HMD mode, a CMOS camera is installed on a personal cinema system to capture the surgical scene in real-time and transmit the image to the host computer through a USB port. In the Google glass mode, a wireless connection is established between the glass and the host computer for image acquisition and data transport tasks. A software program is written in Python to call OpenCV functions for image calibration, co-registration, fusion, and display with augmented reality. The imaging performance of the surgical navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex vivo tissue model. Surgical margins identified by the wearable navigation system are co-incident with those acquired by a standard small animal imaging system, indicating the technical feasibility for intraoperative surgical margin detection. The proposed surgical navigation system combines the sensitivity and specificity of a fluorescence imaging system and the mobility of a wearable goggle. It can be potentially used by a surgeon to identify the residual tumor foci and reduce the risk of recurrent diseases without interfering with the regular resection procedure. PMID:24980159

  8. TU-C-BRD-01: Image Guided SBRT I: Multi-Modality 4D Imaging

    SciTech Connect

    Cai, J; Mageras, G; Pan, T

    2014-06-15

    Motion management is one of the critical technical challenges for radiation therapy. 4D imaging has been rapidly adopted as essential tool to assess organ motion associated with respiratory breathing. A variety of 4D imaging techniques have been developed and are currently under development based on different imaging modalities such as CT, MRI, PET, and CBCT. Each modality provides specific and complementary information about organ and tumor respiratory motion. Effective use of each different technique or combined use of different techniques can introduce a comprehensive management of tumor motion. Specifically, these techniques have afforded tremendous opportunities to better define and delineate tumor volumes, more accurately perform patient positioning, and effectively apply highly conformal therapy techniques such as IMRT and SBRT. Successful implementation requires good understanding of not only each technique, including unique features, limitations, artifacts, imaging acquisition and process, but also how to systematically apply the information obtained from different imaging modalities using proper tools such as deformable image registration. Furthermore, it is important to understand the differences in the effects of breathing variation between different imaging modalities. A comprehensive motion management strategy using multi-modality 4D imaging has shown promise in improving patient care, but at the same time faces significant challenges. This session will focuses on the current status and advances in imaging respiration-induced organ motion with different imaging modalities: 4D-CT, 4D-MRI, 4D-PET, and 4D-CBCT/DTS. Learning Objectives: Understand the need and role of multimodality 4D imaging in radiation therapy. Understand the underlying physics behind each 4D imaging technique. Recognize the advantages and limitations of each 4D imaging technique.

  9. Image-guided thoracoscopic surgery with dye localization in a hybrid operating room

    PubMed Central

    Yang, Shun-Mao; Ko, Wei-Chun; Lin, Mong-Wei; Chan, Chih-Yang; Wu, I-Hui; Chang, Yeun-Chung

    2016-01-01

    Background The rate of detection of small pulmonary nodules (SPNs) has increased. Thoracoscopic resection following image-guided localization had been a reliable alternative in their treatment. We present our experience with image-guided dye localization using robotic C-arm computed tomography (CT) followed by immediate video-assisted thoracoscopic surgery (VATS) for SPNs in a hybrid operating room (OR). Methods From July 2015 to July 2016, 25 consecutive patients with SPNs smaller than 2 cm underwent robotic C-arm CT-guided blue dye tattooing followed by immediate VATS in a hybrid OR. Their medical records were retrospectively reviewed to evaluate the feasibility and safety of this novel procedure. Results Robotic C-arm CT-guided dye localization was successfully performed in 23 patients (92%). Wound extension was required for nodule identification in the remaining two patients. The median size of the nodules was 1.0 cm (range, 0.6–2.0 cm). The median needle localization time and surgery time were 46 and 109 min, respectively. All 25 patients had successful resection of their lesions. The pathological diagnoses were primary lung adenocarcinoma in 18 (72%), benign tumors in 5 (20%), and metastatic lesions in 2 (8%). There was no operative mortality. The median length of the postoperative stay was 3 days (range, 2–8 days). Complications were noted in two patients (8%). One patient had a penetrating injury of the diaphragm during needle localization. The other had pneumonia postoperatively. Both patients were managed conservatively. Conclusions Our experience showed that robotic C-arm CT-guided dye localization followed by immediate thoracoscopic surgery in a hybrid OR is safe and feasible. It may become an effective and attractive alternative in managing SPNs. PMID:28066670

  10. An image-guided precision proton radiation platform for preclinical in vivo research

    NASA Astrophysics Data System (ADS)

    Ford, E.; Emery, R.; Huff, D.; Narayanan, M.; Schwartz, J.; Cao, N.; Meyer, J.; Rengan, R.; Zeng, J.; Sandison, G.; Laramore, G.; Mayr, N.

    2017-01-01

    There are many unknowns in the radiobiology of proton beams and other particle beams. We describe the development and testing of an image-guided low-energy proton system optimized for radiobiological research applications. A 50 MeV proton beam from an existing cyclotron was modified to produce collimated beams (as small as 2 mm in diameter). Ionization chamber and radiochromic film measurements were performed and benchmarked with Monte Carlo simulations (TOPAS). The proton beam was aligned with a commercially-available CT image-guided x-ray irradiator device (SARRP, Xstrahl Inc.). To examine the alternative possibility of adapting a clinical proton therapy system, we performed Monte Carlo simulations of a range-shifted 100 MeV clinical beam. The proton beam exhibits a pristine Bragg Peak at a depth of 21 mm in water with a dose rate of 8.4 Gy min‑1 (3 mm depth). The energy of the incident beam can be modulated to lower energies while preserving the Bragg peak. The LET was: 2.0 keV µm‑1 (water surface), 16 keV µm‑1 (Bragg peak), 27 keV µm‑1 (10% peak dose). Alignment of the proton beam with the SARRP system isocenter was measured at 0.24 mm agreement. The width of the beam changes very little with depth. Monte Carlo-based calculations of dose using the CT image data set as input demonstrate in vivo use. Monte Carlo simulations of the modulated 100 MeV clinical proton beam show a significantly reduced Bragg peak. We demonstrate the feasibility of a proton beam integrated with a commercial x-ray image-guidance system for preclinical in vivo studies. To our knowledge this is the first description of an experimental image-guided proton beam for preclinical radiobiology research. It will enable in vivo investigations of radiobiological effects in proton beams.

  11. An image-guided precision proton radiation platform for preclinical in vivo research.

    PubMed

    Ford, E; Emery, R; Huff, D; Narayanan, M; Schwartz, J; Cao, N; Meyer, J; Rengan, R; Zeng, J; Sandison, G; Laramore, G; Mayr, N

    2017-01-07

    There are many unknowns in the radiobiology of proton beams and other particle beams. We describe the development and testing of an image-guided low-energy proton system optimized for radiobiological research applications. A 50 MeV proton beam from an existing cyclotron was modified to produce collimated beams (as small as 2 mm in diameter). Ionization chamber and radiochromic film measurements were performed and benchmarked with Monte Carlo simulations (TOPAS). The proton beam was aligned with a commercially-available CT image-guided x-ray irradiator device (SARRP, Xstrahl Inc.). To examine the alternative possibility of adapting a clinical proton therapy system, we performed Monte Carlo simulations of a range-shifted 100 MeV clinical beam. The proton beam exhibits a pristine Bragg Peak at a depth of 21 mm in water with a dose rate of 8.4 Gy min(-1) (3 mm depth). The energy of the incident beam can be modulated to lower energies while preserving the Bragg peak. The LET was: 2.0 keV µm(-1) (water surface), 16 keV µm(-1) (Bragg peak), 27 keV µm(-1) (10% peak dose). Alignment of the proton beam with the SARRP system isocenter was measured at 0.24 mm agreement. The width of the beam changes very little with depth. Monte Carlo-based calculations of dose using the CT image data set as input demonstrate in vivo use. Monte Carlo simulations of the modulated 100 MeV clinical proton beam show a significantly reduced Bragg peak. We demonstrate the feasibility of a proton beam integrated with a commercial x-ray image-guidance system for preclinical in vivo studies. To our knowledge this is the first description of an experimental image-guided proton beam for preclinical radiobiology research. It will enable in vivo investigations of radiobiological effects in proton beams.

  12. A multimodal image guiding system for Navigated Ultrasound Bronchoscopy (EBUS): A human feasibility study

    PubMed Central

    Hofstad, Erlend Fagertun; Amundsen, Tore; Langø, Thomas; Bakeng, Janne Beate Lervik; Leira, Håkon Olav

    2017-01-01

    Background Endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) is the endoscopic method of choice for confirming lung cancer metastasis to mediastinal lymph nodes. Precision is crucial for correct staging and clinical decision-making. Navigation and multimodal imaging can potentially improve EBUS-TBNA efficiency. Aims To demonstrate the feasibility of a multimodal image guiding system using electromagnetic navigation for ultrasound bronchoschopy in humans. Methods Four patients referred for lung cancer diagnosis and staging with EBUS-TBNA were enrolled in the study. Target lymph nodes were predefined from the preoperative computed tomography (CT) images. A prototype convex probe ultrasound bronchoscope with an attached sensor for position tracking was used for EBUS-TBNA. Electromagnetic tracking of the ultrasound bronchoscope and ultrasound images allowed fusion of preoperative CT and intraoperative ultrasound in the navigation software. Navigated EBUS-TBNA was used to guide target lymph node localization and sampling. Navigation system accuracy was calculated, measured by the deviation between lymph node position in ultrasound and CT in three planes. Procedure time, diagnostic yield and adverse events were recorded. Results Preoperative CT and real-time ultrasound images were successfully fused and displayed in the navigation software during the procedures. Overall navigation accuracy (11 measurements) was 10.0 ± 3.8 mm, maximum 17.6 mm, minimum 4.5 mm. An adequate sample was obtained in 6/6 (100%) of targeted lymph nodes. No adverse events were registered. Conclusions Electromagnetic navigated EBUS-TBNA was feasible, safe and easy in this human pilot study. The clinical usefulness was clearly demonstrated. Fusion of real-time ultrasound, preoperative CT and electromagnetic navigational bronchoscopy provided a controlled guiding to level of target, intraoperative overview and procedure documentation. PMID:28182758

  13. Image-Based Monitoring of Magnetic Resonance-Guided Thermoablative Therapies for Liver Tumors

    SciTech Connect

    Rempp, Hansjoerg Clasen, Stephan; Pereira, Philippe L.

    2012-12-15

    Minimally invasive treatment options for liver tumor therapy have been increasingly used during the last decade because their benefit has been proven for primary and inoperable secondary liver tumors. Among these, radiofrequency ablation has gained widespread consideration. Optimal image-guidance offers precise anatomical information, helps to position interventional devices, and allows for differentiation between already-treated and remaining tumor tissue. Patient safety and complete ablation of the entire tumor are the overriding objectives of tumor ablation. These may be achieved most elegantly with magnetic resonance (MR)-guided therapy, where monitoring can be performed based on precise soft-tissue imaging and additional components, such as diffusion-weighted imaging and temperature mapping. New MR scanner types and newly developed sequence techniques have enabled MR-guided intervention to move beyond the experimental phase. This article reviews the current role of MR imaging in guiding radiofrequency ablation. Signal characteristics of primary and secondary liver tumors are identified, and signal alteration during therapy is described. Diffusion-weighted imaging (DWI) and temperature mapping as special components of MR therapy monitoring are introduced. Practical information concerning coils, sequence selection, and parameters, as well as sequence gating, is given. In addition, sources of artifacts are identified and techniques to decrease them are introduced, and the characteristic signs of residual tumor in T1-, T2-, and DWI are described. We hope to enable the reader to choose MR sequences that allow optimal therapy monitoring depending on the initial signal characteristics of the tumor as well as its size and location in the liver.

  14. Molecular PET/CT imaging-guided radiation therapy treatment planning.

    PubMed

    Zaidi, Habib; Vees, Hansjörg; Wissmeyer, Michael

    2009-09-01

    The role of positron emission tomography (PET) during the past decade has evolved rapidly from that of a pure research tool to a methodology of enormous clinical potential. (18)F-fluorodeoxyglucose (FDG)-PET is currently the most widely used probe in the diagnosis, staging, assessment of tumor response to treatment, and radiation therapy planning because metabolic changes generally precede the more conventionally measured parameter of change in tumor size. Data accumulated rapidly during the last decade, thus validating the efficacy of FDG imaging and many other tracers in a wide variety of malignant tumors with sensitivities and specificities often in the high 90 percentile range. As a result, PET/computed tomography (CT) had a significant impact on the management of patients because it obviated the need for further evaluation, guided further diagnostic procedures, and assisted in planning therapy for a considerable number of patients. On the other hand, the progress in radiation therapy technology has been enormous during the last two decades, now offering the possibility to plan highly conformal radiation dose distributions through the use of sophisticated beam targeting techniques such as intensity-modulated radiation therapy (IMRT) using tomotherapy, volumetric modulated arc therapy, and many other promising technologies for sculpted three-dimensional (3D) dose distribution. The foundation of molecular imaging-guided radiation therapy lies in the use of advanced imaging technology for improved definition of tumor target volumes, thus relating the absorbed dose information to image-based patient representations. This review documents technological advancements in the field concentrating on the conceptual role of molecular PET/CT imaging in radiation therapy treatment planning and related image processing issues with special emphasis on segmentation of medical images for the purpose of defining target volumes. There is still much more work to be done and many of

  15. SU-E-J-181: Magnetic Resonance Image-Guided Radiation Therapy Workflow: Initial Clinical Experience

    SciTech Connect

    Green, O; Kashani, R; Santanam, L; Wooten, H; Li, H; Rodriguez, V; Hu, Y; Mutic, S; Hand, T; Victoria, J; Steele, C

    2014-06-01

    Purpose: The aims of this work are to describe the workflow and initial clinical experience treating patients with an MRI-guided radiotherapy (MRIGRT) system. Methods: Patient treatments with a novel MR-IGRT system started at our institution in mid-January. The system consists of an on-board 0.35-T MRI, with IMRT-capable delivery via doubly-focused MLCs on three {sup 60} Co heads. In addition to volumetric MR-imaging, real-time planar imaging is performed during treatment. So far, eleven patients started treatment (six finished), ranging from bladder to lung SBRT. While the system is capable of online adaptive radiotherapy and gating, a conventional workflow was used to start, consisting of volumetric imaging for patient setup using visible tumor, evaluation of tumor motion outside of PTV on cine images, and real-time imaging. Workflow times were collected and evaluated to increase efficiency and evaluate feasibility of adding the adaptive and gating features while maintaining a reasonable patient throughput. Results: For the first month, physicians attended every fraction to provide guidance on identifying the tumor and an acceptable level of positioning and anatomical deviation. Average total treatment times (including setup) were reduced from 55 to 45 min after physician presence was no longer required and the therapists had learned to align patients based on soft-tissue imaging. Presently, the source strengths were at half maximum (7.7K Ci each), therefore beam-on times will be reduced after source replacement. Current patient load is 10 per day, with increase to 25 anticipated in the near future. Conclusion: On-board, real-time MRI-guided RT has been incorporated into clinical use. Treatment times were kept to reasonable lengths while including volumetric imaging, previews of tumor movement, and physician evaluation. Workflow and timing is being continuously evaluated to increase efficiency. In near future, adaptive and gating capabilities of the system will

  16. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

    PubMed

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-07

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  17. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  18. Segmentation of left atrial intracardiac ultrasound images for image guided cardiac ablation therapy

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Stephens, T.; Holmes, D. R.; Linte, C.; Packer, D. L.; Robb, R. A.

    2013-03-01

    Intracardiac echocardiography (ICE), a technique in which structures of the heart are imaged using a catheter navigated inside the cardiac chambers, is an important imaging technique for guidance in cardiac ablation therapy. Automatic segmentation of these images is valuable for guidance and targeting of treatment sites. In this paper, we describe an approach to segment ICE images by generating an empirical model of blood pool and tissue intensities. Normal, Weibull, Gamma, and Generalized Extreme Value (GEV) distributions are fit to histograms of tissue and blood pool pixels from a series of ICE scans. A total of 40 images from 4 separate studies were evaluated. The model was trained and tested using two approaches. In the first approach, the model was trained on all images from 3 studies and subsequently tested on the 40 images from the 4th study. This procedure was repeated 4 times using a leave-one-out strategy. This is termed the between-subjects approach. In the second approach, the model was trained on 10 randomly selected images from a single study and tested on the remaining 30 images in that study. This is termed the within-subjects approach. For both approaches, the model was used to automatically segment ICE images into blood and tissue regions. Each pixel is classified using the Generalized Liklihood Ratio Test across neighborhood sizes ranging from 1 to 49. Automatic segmentation results were compared against manual segmentations for all images. In the between-subjects approach, the GEV distribution using a neighborhood size of 17 was found to be the most accurate with a misclassification rate of approximately 17%. In the within-subjects approach, the GEV distribution using a neighborhood size of 19 was found to be the most accurate with a misclassification rate of approximately 15%. As expected, the majority of misclassified pixels were located near the boundaries between tissue and blood pool regions for both methods.

  19. SU-E-J-248: Comparative Study of Two Image Registration for Image-Guided Radiation Therapy in Esophageal Cancer

    SciTech Connect

    Shang, K; Wang, J; Liu, D; Li, R; Cao, Y; Chi, Z

    2014-06-01

    Purpose: Image-guided radiation therapy (IGRT) is one of the major treatment of esophageal cancer. Gray value registration and bone registration are two kinds of image registration, the purpose of this work is to compare which one is more suitable for esophageal cancer patients. Methods: Twenty three esophageal patients were treated by Elekta Synergy, CBCT images were acquired and automatically registered to planning kilovoltage CT scans according to gray value or bone registration. The setup errors were measured in the X, Y and Z axis, respectively. Two kinds of setup errors were analysed by matching T test statistical method. Results: Four hundred and five groups of CBCT images were available and the systematic and random setup errors (cm) in X, Y, Z directions were 0.35, 0.63, 0.29 and 0.31, 0.53, 0.21 with gray value registration, while 0.37, 0.64, 0.26 and 0.32, 0.55, 0.20 with bone registration, respectively. Compared with bone registration and gray value registration, the setup errors in X and Z axis have significant differences. In Y axis, both measurement comparison results of T value is 0.256 (P value > 0.05); In X axis, the T value is 5.287(P value < 0.05); In Z axis, the T value is −5.138 (P value < 0.05). Conclusion: Gray value registration is recommended in image-guided radiotherapy for esophageal cancer and the other thoracic tumors. Manual registration could be applied when it is necessary. Bone registration is more suitable for the head tumor and pelvic tumor department where composed of redundant interconnected and immobile bone tissue.

  20. Optical Clearing of the Skin for Near-Infrared Fluorescence Image-Guided Surgery

    PubMed Central

    Matsui, Aya; Lomnes, Stephen J.; Frangioni, John V.

    2009-01-01

    Near-infrared (NIR) light penetrates relatively deep into skin, but its usefulness for biomedical imaging is constrained by high scattering of living tissue. Previous studies have suggested that treatment with hyperosmotic “clearing” agents might change the optical properties of tissue, resulting in improved photon transport and reduced scatter. Since this would have a profound impact on image-guided surgery, we sought to quantify the magnitude of the optical clearing effect in living subjects. A custom NIR imaging system was used to perform sentinel lymph node mapping and superficial perforator angiography in vivo on 35 kg pigs in the presence or absence of glycerol or PPG:PEG pre-treatment of skin. Ex vivo, NIR fluorescent standards were placed at a fixed distance beneath sections of excised porcine skin, either preserved in saline or stored dry, then treated or not treated with glycerol. Fluorescence intensity through the skin was quantified and analyzed statistically. Surprisingly, the expected increase in intensity was not measurable either in vivo or ex vivo, unless the skin was previously dried. Histological evaluation showed a morphological difference only in stratum corneum, with this difference being negligible in living tissue. In conclusion, topically applied hyperosmotic agents are ineffective for image-guided surgery of living subjects. PMID:19405749

  1. Image guided Brachytherapy: The paradigm of Gynecologic and Partial Breast HDR Brachytherapy

    NASA Astrophysics Data System (ADS)

    Diamantopoulos, S.; Kantemiris, I.; Konidari, A.; Zaverdinos, P.

    2015-09-01

    High dose rate (HDR) brachytherapy uses high strength radioactive sources and temporary interstitial implants to conform the dose to target and minimize the treatment time. The advances of imaging technology enable accurate reconstruction of the implant and exact delineation of high-risk CTV and the surrounding critical structures. Furthermore, with sophisticated treatment planning systems, applicator devices and stepping source afterloaders, brachytherapy evolved to a more precise, safe and individualized treatment. At the Radiation Oncology Department of Metropolitan Hospital Athens, MRI guided HDR gynecologic (GYN) brachytherapy and accelerated partial breast irradiation (APBI) with brachytherapy are performed routinely. Contouring and treatment planning are based on the recommendations of the GEC - ESTRO Working group. The task of this presentation is to reveal the advantages of 3D image guided brachytherapy over 2D brachytherapy. Thus, two patients treated at our department (one GYN and one APBI) will be presented. The advantage of having adequate dose coverage of the high risk CTV and simultaneous low doses to the OARs when using 3D image- based brachytherapy will be presented. The treatment techniques, equipment issues, as well as implantation, imaging and treatment planning procedures will be described. Quality assurance checks will be treated separately.

  2. Automatic electrode configuration selection for image-guided cochlear implant programming

    NASA Astrophysics Data System (ADS)

    Zhao, Yiyuan; Dawant, Benoit M.; Noble, Jack H.

    2015-03-01

    Cochlear implants (CIs) are neural prosthetics that stimulate the auditory nerve pathways within the cochlea using an implanted electrode array to restore hearing. After implantation, the CI is programmed by an audiologist who determines which electrodes are active, i.e., the electrode configuration, and selects other stimulation settings. Recent clinical studies by our group have shown that hearing outcomes can be significantly improved by using an image-guided electrode configuration selection technique we have designed. Our goal in this work is to automate the electrode configuration selection step with the long term goal of developing a fully automatic system that can be translated to the clinic. Until now, the electrode configuration selection step has been performed by an expert with the assistance of image analysis-based estimates of the electrode-neural interface. To automatically determine the electrode configuration, we have designed an optimization approach and propose the use of a cost function with feature terms designed to interpret the image analysis data in a similar fashion as the expert. Further, we have designed an approach to select parameters in the cost function using our database of existing electrode configuration plans as training data. The results we present show that our automatic approach results in electrode configurations that are better or equally as good as manually selected configurations in over 80% of the cases tested. This method represents a crucial step towards clinical translation of our image-guided cochlear implant programming system.

  3. Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update.

    PubMed

    Ahmed, Muneeb; Solbiati, Luigi; Brace, Christopher L; Breen, David J; Callstrom, Matthew R; Charboneau, J William; Chen, Min-Hua; Choi, Byung Ihn; de Baère, Thierry; Dodd, Gerald D; Dupuy, Damian E; Gervais, Debra A; Gianfelice, David; Gillams, Alice R; Lee, Fred T; Leen, Edward; Lencioni, Riccardo; Littrup, Peter J; Livraghi, Tito; Lu, David S; McGahan, John P; Meloni, Maria Franca; Nikolic, Boris; Pereira, Philippe L; Liang, Ping; Rhim, Hyunchul; Rose, Steven C; Salem, Riad; Sofocleous, Constantinos T; Solomon, Stephen B; Soulen, Michael C; Tanaka, Masatoshi; Vogl, Thomas J; Wood, Bradford J; Goldberg, S Nahum

    2014-10-01

    Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. Online supplemental material is available for this article .

  4. Image-guided tumor ablation: standardization of terminology and reporting criteria--a 10-year update.

    PubMed

    Ahmed, Muneeb; Solbiati, Luigi; Brace, Christopher L; Breen, David J; Callstrom, Matthew R; Charboneau, J William; Chen, Min-Hua; Choi, Byung Ihn; de Baère, Thierry; Dodd, Gerald D; Dupuy, Damian E; Gervais, Debra A; Gianfelice, David; Gillams, Alice R; Lee, Fred T; Leen, Edward; Lencioni, Riccardo; Littrup, Peter J; Livraghi, Tito; Lu, David S; McGahan, John P; Meloni, Maria Franca; Nikolic, Boris; Pereira, Philippe L; Liang, Ping; Rhim, Hyunchul; Rose, Steven C; Salem, Riad; Sofocleous, Constantinos T; Solomon, Stephen B; Soulen, Michael C; Tanaka, Masatoshi; Vogl, Thomas J; Wood, Bradford J; Goldberg, S Nahum

    2014-11-01

    Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes.

  5. Image-guided Tumor Ablation: Standardization of Terminology and Reporting Criteria—A 10-Year Update

    PubMed Central

    Solbiati, Luigi; Brace, Christopher L.; Breen, David J.; Callstrom, Matthew R.; Charboneau, J. William; Chen, Min-Hua; Choi, Byung Ihn; de Baère, Thierry; Dodd, Gerald D.; Dupuy, Damian E.; Gervais, Debra A.; Gianfelice, David; Gillams, Alice R.; Lee, Fred T.; Leen, Edward; Lencioni, Riccardo; Littrup, Peter J.; Livraghi, Tito; Lu, David S.; McGahan, John P.; Meloni, Maria Franca; Nikolic, Boris; Pereira, Philippe L.; Liang, Ping; Rhim, Hyunchul; Rose, Steven C.; Salem, Riad; Sofocleous, Constantinos T.; Solomon, Stephen B.; Soulen, Michael C.; Tanaka, Masatoshi; Vogl, Thomas J.; Wood, Bradford J.; Goldberg, S. Nahum

    2014-01-01

    Image-guided tumor ablation has become a well-established hallmark of local cancer therapy. The breadth of options available in this growing field increases the need for standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison among treatments that use different technologies, such as chemical (eg, ethanol or acetic acid) ablation, thermal therapies (eg, radiofrequency, laser, microwave, focused ultrasound, and cryoablation) and newer ablative modalities such as irreversible electroporation. This updated consensus document provides a framework that will facilitate the clearest communication among investigators regarding ablative technologies. An appropriate vehicle is proposed for reporting the various aspects of image-guided ablation therapy including classification of therapies, procedure terms, descriptors of imaging guidance, and terminology for imaging and pathologic findings. Methods are addressed for standardizing reporting of technique, follow-up, complications, and clinical results. As noted in the original document from 2003, adherence to the recommendations will improve the precision of communications in this field, leading to more accurate comparison of technologies and results, and ultimately to improved patient outcomes. © RSNA, 2014 Online supplemental material is available for this article. PMID:24927329

  6. Indocyanine Green-Loaded Nanoparticles for Image-Guided Tumor Surgery

    PubMed Central

    Hill, Tanner K.; Abdulahad, Asem; Kelkar, Sneha S.; Marini, Frank C.; Long, Timothy E.; Provenzale, James M.; Mohs, Aaron M.

    2015-01-01

    Detecting positive tumor margins and local malignant masses during surgery is critical for long-term patient survival. The use of image-guided surgery for tumor removal, particularly with near-infrared fluorescent imaging, is a potential method to facilitate removing all neoplastic tissue at the surgical site. In this study we demonstrate a series of hyaluronic acid (HLA)-derived nanoparticles that entrap the near-infrared dye indocyanine green, termed NanoICG, for improved delivery of the dye to tumors. Self-assembly of the nanoparticles was driven by conjugation of one of three hydrophobic moieties: aminopropyl-1-pyrenebutanamide (PBA), aminopropyl-5β-cholanamide (5βCA), or octadecylamine (ODA). Nanoparticle self-assembly, dye loading, and optical properties were characterized. NanoICG exhibited quenched fluorescence that could be activated by disassembly in a mixed solvent. NanoICG was found to be nontoxic at physiologically relevant concentrations and exposure was not found to inhibit cell growth. Using an MDA-MB-231 tumor xenograft model in mice, strong fluorescence enhancement in tumors was observed with NanoICG using a fluorescence image-guided surgery system and a whole-animal imaging system. Tumor contrast with NanoICG was significantly higher than with ICG alone. PMID:25565445

  7. Multifunctional gold nanorods for image-guided surgery and photothermal therapy

    NASA Astrophysics Data System (ADS)

    Barriere, Clement; Qi, Ji; Garcia-Allende, P. Beatriz; Newton, Richard; Elson, Daniel S.

    2012-03-01

    Nanoparticles are viewed as a promising tool for numerous medical applications, for instance imaging and photothermal therapy (PTT) has been proposed using gold nanorods. We are developing multi-functional gold nanorods (m-GNRs) which have potential for image guided endoscopic surgery of tumour tissue with a modified laparoscope system. A new synthesis method potentially allows any useful acid functionalised molecules to be bonded at the surface. We have created fluorescent m-GNRs which can be used for therapy as they absorb light in the infrared, which may penetrate deep into the tissue and produce localised heating. We have performed a tissue based experiment to demonstrate the feasibility of fluorescence guided PTT using m- GNRs. Ex vivo tests were performed using sheep heart. This measurement, correlated with the fluorescence signal of the m-GNRs measured by the laparoscope allows the clear discrimination of the artery system containing m-GNRs. A laser diode was used to heat the m-GNRs and a thermal camera was able to record the heat distribution. These images were compared to the fluorescence images for validation.

  8. Indocyanine green-loaded nanoparticles for image-guided tumor surgery.

    PubMed

    Hill, Tanner K; Abdulahad, Asem; Kelkar, Sneha S; Marini, Frank C; Long, Timothy E; Provenzale, James M; Mohs, Aaron M

    2015-02-18

    Detecting positive tumor margins and local malignant masses during surgery is critical for long-term patient survival. The use of image-guided surgery for tumor removal, particularly with near-infrared fluorescent imaging, is a potential method to facilitate removing all neoplastic tissue at the surgical site. In this study we demonstrate a series of hyaluronic acid (HLA)-derived nanoparticles that entrap the near-infrared dye indocyanine green, termed NanoICG, for improved delivery of the dye to tumors. Self-assembly of the nanoparticles was driven by conjugation of one of three hydrophobic moieties: aminopropyl-1-pyrenebutanamide (PBA), aminopropyl-5β-cholanamide (5βCA), or octadecylamine (ODA). Nanoparticle self-assembly, dye loading, and optical properties were characterized. NanoICG exhibited quenched fluorescence that could be activated by disassembly in a mixed solvent. NanoICG was found to be nontoxic at physiologically relevant concentrations and exposure was not found to inhibit cell growth. Using an MDA-MB-231 tumor xenograft model in mice, strong fluorescence enhancement in tumors was observed with NanoICG using a fluorescence image-guided surgery system and a whole-animal imaging system. Tumor contrast with NanoICG was significantly higher than with ICG alone.

  9. Sodium Laser Guide Star Adaptive Optics Imaging Polarimetry of Herbig Ae/Be Stars

    SciTech Connect

    Perrin, M D; Graham, J R; Lloyd, J P; Kalas, P; Gates, E L; Gavel, D T; Pennington, D M; Max, C E

    2004-01-08

    The future of high-resolution ground-based optical and infrared astronomy requires the successful implementation of laser guide star adaptive optics systems. We present the first science results from the Lick Observatory sodium beacon laser guide star system. By coupling this system to a near-infrared (J;H;Ks bands) dual-channel imaging polarimeter, we achieve very high sensitivity to light scattered in the circumstellar enviroment of Herbig Ae/Be stars on scales of 100-300 AU. Observations of LkH{alpha} 198 reveal a highly polarized, biconical nebula 10 arcseconds in diameter (6000 AU) . We also observe a polarized jet-like feature associated with the deeply embedded source LkH{alpha} 198-IR. The star LkH{alpha} 233 presents a narrow, unpolarized dark lane dividing its characteristic butterfly-shaped polarized reflection nebulosity. This linear structure is oriented perpendicular to an optical jet and bipolar cavity and is consistent with the presence of an optically thick circumstellar disk blocking our direct view of the star. These data suggest that the evolutionary picture developed for the lower-mass T Tauri stars is also relevant to the Herbig Ae/Be stars and demonstrate the ability of laser guide star adaptive optics systems to obtain scientific results competitive with natural guide star adaptive optics or space-based telescopes.

  10. Correlation based 3-D segmentation of the left ventricle in pediatric echocardiographic images using radio-frequency data.

    PubMed

    Nillesen, Maartje M; Lopata, Richard G P; Huisman, H J; Thijssen, Johan M; Kapusta, Livia; de Korte, Chris L

    2011-09-01

    Clinical diagnosis of heart disease might be substantially supported by automated segmentation of the endocardial surface in three-dimensional (3-D) echographic images. Because of the poor echogenicity contrast between blood and myocardial tissue in some regions and the inherent speckle noise, automated analysis of these images is challenging. A priori knowledge on the shape of the heart cannot always be relied on, e.g., in children with congenital heart disease, segmentation should be based on the echo features solely. The objective of this study was to investigate the merit of using temporal cross-correlation of radio-frequency (RF) data for automated segmentation of 3-D echocardiographic images. Maximum temporal cross-correlation (MCC) values were determined locally from the RF-data using an iterative 3-D technique. MCC values as well as a combination of MCC values and adaptive filtered, demodulated RF-data were used as an additional, external force in a deformable model approach to segment the endocardial surface and were tested against manually segmented surfaces. Results on 3-D full volume images (Philips, iE33) of 10 healthy children demonstrate that MCC values derived from the RF signal yield a useful parameter to distinguish between blood and myocardium in regions with low echogenicity contrast and incorporation of MCC improves the segmentation results significantly. Further investigation of the MCC over the whole cardiac cycle is required to exploit the full benefit of it for automated segmentation.

  11. Radio Sounding Science at High Powers

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Reinisch, B. W.; Song, P.; Fung, S. F.; Benson, R. F.; Taylor, W. W. L.; Cooper, J. F.; Garcia, L.; Markus, T.; Gallagher, D. L.

    2004-01-01

    Future space missions like the Jupiter Icy Moons Orbiter (JIMO) planned to orbit Callisto, Ganymede, and Europa can fully utilize a variable power radio sounder instrument. Radio sounding at 1 kHz to 10 MHz at medium power levels (10 W to kW) will provide long-range magnetospheric sounding (several Jovian radii) like those first pioneered by the radio plasma imager instrument on IMAGE at low power (less than l0 W) and much shorter distances (less than 5 R(sub E)). A radio sounder orbiting a Jovian icy moon would be able to globally measure time-variable electron densities in the moon ionosphere and the local magnetospheric environment. Near-spacecraft resonance and guided echoes respectively allow measurements of local field magnitude and local field line geometry, perturbed both by direct magnetospheric interactions and by induced components from subsurface oceans. JIMO would allow radio sounding transmissions at much higher powers (approx. 10 kW) making subsurface sounding of the Jovian icy moons possible at frequencies above the ionosphere peak plasma frequency. Subsurface variations in dielectric properties, can be probed for detection of dense and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts.

  12. [Wavelet NeighShrink method for grid texture removal in image of solar radio bursts].

    PubMed

    Zhao, Rui-zhen; Hu, Zhan-yi

    2007-01-01

    The data received from solar bursts contain a lot of noise, which makes further processing more difficult. To remove the noise and enhance the image, we studied the properties of the NeighShrink threshold function and analyzed the influence of neighborhood window size on the denoising result, on the basis of which a new wavelet NeighShrink square root method for image denoising is presented. Firstly, each channel of the solar burst image is normalized, which can, to some extent, remove the horizontal grid texture in the image. Secondly, the preprocessed image is decomposed by wavelet transform, and the obtained wavelet coefficients are thresholded by NeighShrink square root method. Finally, the denoised image is reconstructed by inverse wavelet transform. The experimental results show that the presented method is effective in noise removal and image enhancement.

  13. Impact of Computed Tomography Image Quality on Image-Guided Radiation Therapy Based on Soft Tissue Registration

    SciTech Connect

    Morrow, Natalya V.; Lawton, Colleen A.; Qi, X. Sharon; Li, X. Allen

    2012-04-01

    Purpose: In image-guided radiation therapy (IGRT), different computed tomography (CT) modalities with varying image quality are being used to correct for interfractional variations in patient set-up and anatomy changes, thereby reducing clinical target volume to the planning target volume (CTV-to-PTV) margins. We explore how CT image quality affects patient repositioning and CTV-to-PTV margins in soft tissue registration-based IGRT for prostate cancer patients. Methods and Materials: Four CT-based IGRT modalities used for prostate RT were considered in this study: MV fan beam CT (MVFBCT) (Tomotherapy), MV cone beam CT (MVCBCT) (MVision; Siemens), kV fan beam CT (kVFBCT) (CTVision, Siemens), and kV cone beam CT (kVCBCT) (Synergy; Elekta). Daily shifts were determined by manual registration to achieve the best soft tissue agreement. Effect of image quality on patient repositioning was determined by statistical analysis of daily shifts for 136 patients (34 per modality). Inter- and intraobserver variability of soft tissue registration was evaluated based on the registration of a representative scan for each CT modality with its corresponding planning scan. Results: Superior image quality with the kVFBCT resulted in reduced uncertainty in soft tissue registration during IGRT compared with other image modalities for IGRT. The largest interobserver variations of soft tissue registration were 1.1 mm, 2.5 mm, 2.6 mm, and 3.2 mm for kVFBCT, kVCBCT, MVFBCT, and MVCBCT, respectively. Conclusions: Image quality adversely affects the reproducibility of soft tissue-based registration for IGRT and necessitates a careful consideration of residual uncertainties in determining different CTV-to-PTV margins for IGRT using different image modalities.