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Sample records for aided surgery patient-specific

  1. Orbital and Maxillofacial Computer Aided Surgery: Patient-Specific Finite Element Models To Predict Surgical Outcomes

    CERN Document Server

    Luboz, V; Swider, P; Payan, Y; Luboz, Vincent; Chabanas, Matthieu; Swider, Pascal; Payan, Yohan

    2005-01-01

    This paper addresses an important issue raised for the clinical relevance of Computer-Assisted Surgical applications, namely the methodology used to automatically build patient-specific Finite Element (FE) models of anatomical structures. From this perspective, a method is proposed, based on a technique called the Mesh-Matching method, followed by a process that corrects mesh irregularities. The Mesh-Matching algorithm generates patient-specific volume meshes from an existing generic model. The mesh regularization process is based on the Jacobian matrix transform related to the FE reference element and the current element. This method for generating patient-specific FE models is first applied to Computer-Assisted maxillofacial surgery, and more precisely to the FE elastic modelling of patient facial soft tissues. For each patient, the planned bone osteotomies (mandible, maxilla, chin) are used as boundary conditions to deform the FE face model, in order to predict the aesthetic outcome of the surgery. Seven F...

  2. Patient Specific Simulation for Planning of Cochlear Implantation Surgery

    DEFF Research Database (Denmark)

    Vera, Sergio; Perez, Frederic; Balust, Clara;

    2014-01-01

    Cochlear implantation is a surgical procedure that can restore the hearing capabilities to patients with severe or complete functional loss. However, the level of restoration varies highly between subjects and depends on patient-specific factors. This paper presents a software application for pla...

  3. A Numerical Multiscale Framework for Modeling Patient-Specific Coronary Artery Bypass Surgeries

    Science.gov (United States)

    Ramachandra, Abhay B.; Kahn, Andrew; Marsden, Alison

    2014-11-01

    Coronary artery bypass graft (CABG) surgery is performed to revascularize diseased coronary arteries, using arterial, venous or synthetic grafts. Vein grafts, used in more than 70% of procedures, have failure rates as high as 50% in less than 10 years. Hemodynamics is known to play a key role in the mechano-biological response of vein grafts, but current non-invasive imaging techniques cannot fully characterize the hemodynamic and biomechanical environment. We numerically compute hemodynamics and wall mechanics in patient-specific 3D CABG geometries using stabilized finite element methods. The 3D patient-specific domain is coupled to a 0D lumped parameter circulatory model and parameters are tuned to match patient-specific blood pressures, stroke volumes, heart rates and heuristic flow-split values. We quantify differences in hemodynamics between arterial and venous grafts and discuss possible correlations to graft failure. Extension to a deformable wall approximation will also be discussed. The quantification of wall mechanics and hemodynamics is a necessary step towards coupling continuum models in solid and fluid mechanics with the cellular and sub-cellular responses of grafts, which in turn, should lead to a more accurate prediction of the long term outcome of CABG surgeries, including predictions of growth and remodeling.

  4. Splintless orthognathic surgery: a novel technique using patient-specific implants (PSI).

    Science.gov (United States)

    Gander, Thomas; Bredell, Marius; Eliades, Theodore; Rücker, Martin; Essig, Harald

    2015-04-01

    In the past few years, advances in three-dimensional imaging have conducted to breakthrough in the diagnosis, treatment planning and result assessment in orthognathic surgery. Hereby error-prone and time-consuming planning steps, like model surgery and transfer of the face bow, can be eluded. Numerous positioning devices, in order to transfer the three-dimensional treatment plan to the intraoperative site, have been described. Nevertheless the use of positioning devices and intraoperative splints are failure-prone and time-consuming steps, which have to be performed during the operation and during general anesthesia of the patient. We describe a novel time-sparing and failsafe technique using patient-specific implants (PSI) as positioning guides and concurrently as rigid fixation of the maxilla in the planned position. This technique avoids elaborate positioning and removal of manufactured positioning devices and allows maxillary positioning without the use of occlusal splints.

  5. Patient-Specific Biomechanical Modeling for Guidance During Minimally-Invasive Hepatic Surgery.

    Science.gov (United States)

    Plantefève, Rosalie; Peterlik, Igor; Haouchine, Nazim; Cotin, Stéphane

    2016-01-01

    During the minimally-invasive liver surgery, only the partial surface view of the liver is usually provided to the surgeon via the laparoscopic camera. Therefore, it is necessary to estimate the actual position of the internal structures such as tumors and vessels from the pre-operative images. Nevertheless, such task can be highly challenging since during the intervention, the abdominal organs undergo important deformations due to the pneumoperitoneum, respiratory and cardiac motion and the interaction with the surgical tools. Therefore, a reliable automatic system for intra-operative guidance requires fast and reliable registration of the pre- and intra-operative data. In this paper we present a complete pipeline for the registration of pre-operative patient-specific image data to the sparse and incomplete intra-operative data. While the intra-operative data is represented by a point cloud extracted from the stereo-endoscopic images, the pre-operative data is used to reconstruct a biomechanical model which is necessary for accurate estimation of the position of the internal structures, considering the actual deformations. This model takes into account the patient-specific liver anatomy composed of parenchyma, vascularization and capsule, and is enriched with anatomical boundary conditions transferred from an atlas. The registration process employs the iterative closest point technique together with a penalty-based method. We perform a quantitative assessment based on the evaluation of the target registration error on synthetic data as well as a qualitative assessment on real patient data. We demonstrate that the proposed registration method provides good results in terms of both accuracy and robustness w.r.t. the quality of the intra-operative data.

  6. Quantification of hepatic flow distribution using particle tracking for patient specific virtual Fontan surgery

    Science.gov (United States)

    Yang, Weiguang; Vignon-Clementel, Irene; Troianowski, Guillaume; Shadden, Shawn; Mohhan Reddy, V.; Feinstein, Jeffrey; Marsden, Alison

    2010-11-01

    The Fontan surgery is the third and final stage in a palliative series to treat children with single ventricle heart defects. In the extracardiac Fontan procedure, the inferior vena cava (IVC) is connected to the pulmonary arteries via a tube-shaped Gore-tex graft. Clinical observations have shown that the absence of a hepatic factor, carried in the IVC flow, can cause pulmonary arteriovenous malformations. Although it is clear that hepatic flow distribution is an important determinant of Fontan performance, few studies have quantified its relation to Fontan design. In this study, we virtually implanted three types of grafts (T-junction, offset and Y-graft) into 5 patient specific models of the Glenn (stage 2) anatomy. We then performed 3D time-dependent simulations and systematically compared the IVC flow distribution, energy loss, and pressure levels in different surgical designs. A robustness test is performed to evaluate the sensitivity of hepatic distribution to pulmonary flow split. Results show that the Y-graft design effectively improves the IVC flow distribution, compared to traditional designs and that surgical designs could be customized on a patient-by-patient basis.

  7. A national center for biocomputation: in search of a patient-specific interactive virtual surgery workbench

    Science.gov (United States)

    Ross, M. D.; Montgomery, K.; Linton, S.; Cheng, R.; Smith, J.

    1998-01-01

    This report describes the three-dimensional imaging and virtual environment technologies developed in NASA's Biocomputation Center for scientific purposes that have now led to applications in the field of medicine. A major goal is to develop a virtual environment surgery workbench for planning complex craniofacial and breast reconstructive surgery, and for training surgeons.

  8. Imaging, virtual planning, design, and production of patient-specific implants and clinical validation in craniomaxillofacial surgery.

    Science.gov (United States)

    Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-M

    2012-09-01

    The purpose of this article was to describe the workflow from imaging, via virtual design, to manufacturing of patient-specific titanium reconstruction plates, cutting guide and mesh, and its utility in connection with surgical treatment of acquired bone defects in the mandible using additive manufacturing by electron beam melting (EBM). Based on computed tomography scans, polygon skulls were created. Following that virtual treatment plans entailing free microvascular transfer of fibula flaps using patient-specific reconstruction plates, mesh, and cutting guides were designed. The design was based on the specification of a Compact UniLOCK 2.4 Large (Synthes(®), Switzerland). The obtained polygon plates were bent virtually round the reconstructed mandibles. Next, the resections of the mandibles were planned virtually. A cutting guide was outlined to facilitate resection, as well as plates and titanium mesh for insertion of bone or bone substitutes. Polygon plates and meshes were converted to stereolithography format and used in the software Magics for preparation of input files for the successive step, additive manufacturing. EBM was used to manufacture the customized implants in a biocompatible titanium grade, Ti6Al4V ELI. The implants and the cutting guide were cleaned and sterilized, then transferred to the operating theater, and applied during surgery. Commercially available software programs are sufficient in order to virtually plan for production of patient-specific implants. Furthermore, EBM-produced implants are fully usable under clinical conditions in reconstruction of acquired defects in the mandible. A good compliance between the treatment plan and the fit was demonstrated during operation. Within the constraints of this article, the authors describe a workflow for production of patient-specific implants, using EBM manufacturing. Titanium cutting guides, reconstruction plates for fixation of microvascular transfer of osteomyocutaneous bone grafts, and

  9. Blood flow modeling for patient-specific bypass surgery in lower-limb arteries

    OpenAIRE

    Willemet, Marie

    2012-01-01

    Every day in Belgium, at least one or two people will undergo a bypass surgery in the lower-limb arteries. This medical procedure consists of replacing an occluded section of the leg arteries with an artificial vessel, in order to allow blood to flow downwards of this blockage. Even though this intervention is very common, failure of this treatment within five years reaches up to 60%. In order to improve our understanding of the causes of bypass failure, one approach is to study the local hem...

  10. Patient-specific simulation of endovascular repair surgery with tortuous aneurysms requiring flexible stent-grafts.

    Science.gov (United States)

    Perrin, David; Badel, Pierre; Orgeas, Laurent; Geindreau, Christian; du Roscoat, Sabine Rolland; Albertini, Jean-Noël; Avril, Stéphane

    2016-10-01

    The rate of post-operative complications is the main drawback of endovascular repair, a technique used to treat abdominal aortic aneurysms. Complex anatomies, featuring short aortic necks and high vessel tortuosity for instance, have been proved likely prone to these complications. In this context, practitioners could benefit, at the preoperative planning stage, from a tool able to predict the post-operative position of the stent-graft, to validate their stent-graft sizing and anticipate potential complications. In consequence, the aim of this work is to prove the ability of a numerical simulation methodology to reproduce accurately the shapes of stent-grafts, with a challenging design, deployed inside tortuous aortic aneurysms. Stent-graft module samples were scanned by X-ray microtomography and subjected to mechanical tests to generate finite-element models. Two EVAR clinical cases were numerically reproduced by simulating stent-graft models deployment inside the tortuous arterial model generated from patient pre-operative scan. In the same manner, an in vitro stent-graft deployment in a rigid polymer phantom, generated by extracting the arterial geometry from the preoperative scan of a patient, was simulated to assess the influence of biomechanical environment unknowns in the in vivo case. Results were validated by comparing stent positions on simulations and post-operative scans. In all cases, simulation predicted stents deployed locations and shapes with an accuracy of a few millimetres. The good results obtained in the in vitro case validated the ability of the methodology to simulate stent-graft deployment in very tortuous arteries and led to think proper modelling of biomechanical environment could reduce the few local discrepancies found in the in vivo case. In conclusion, this study proved that our methodology can achieve accurate simulation of stent-graft deployed shape even in tortuous patient specific aortic aneurysms and may be potentially helpful to

  11. The Numerical Study of the Hemodynamic Characteristics in the Patient-Specific Intracranial Aneurysms before and after Surgery

    Science.gov (United States)

    Byun, Jun Soo; Choi, Sun-Young

    2016-01-01

    The patient-specific pre- and postsurgery cerebral arterial geometries in the study were reconstructed from computed tomography angiography (CTA). Three-dimensional computational fluid dynamics models were used to investigate the hemodynamic phenomena in the cerebral arteries before and after surgery of the aneurysm under realistic conditions. CFD simulations for laminar flow of incompressible Newtonian fluid were conducted by using commercial software, ANSYS v15, with the rigid vascular wall assumption. The study found that the flow patterns with the complex vortical structures inside the aneurysm were similar. We also found that the inflow jet streams were coming strongly in aneurysm sac in the presurgery models, while the flow patterns in postsurgery models were quite different from those in presurgery models. The average wall shear stress after surgery for model 1 was approximately three times greater than that before surgery, while it was about twenty times greater for model 2. The area of low WSS in the daughter saccular aneurysm region in model 2 is associated with aneurysm rupture. Thus the distribution of WSS in aneurysm region provides useful prediction for the risk of aneurysm rupture. PMID:27274764

  12. Patient-specific port placement for laparoscopic surgery using atlas-based registration

    Science.gov (United States)

    Enquobahrie, Andinet; Shivaprabhu, Vikas; Aylward, Stephen; Finet, Julien; Cleary, Kevin; Alterovitz, Ron

    2013-03-01

    Laparoscopic surgery is a minimally invasive surgical approach, in which abdominal surgical procedures are performed through trocars via small incisions. Patients benefit by reduced postoperative pain, shortened hospital stays, improved cosmetic results, and faster recovery times. Optimal port placement can improve surgeon dexterity and avoid the need to move the trocars, which would cause unnecessary trauma to the patient. We are building an intuitive open source visualization system to help surgeons identify ports. Our methodology is based on an intuitive port placement visualization module and atlas-based registration algorithm to transfer port locations to individual patients. The methodology follows three steps:1) Use a port placement visualization module to manually place ports in an abdominal organ atlas. This step generates port-augmented abdominal atlas. This is done only once for a given patient population. 2) Register the atlas data with the patient CT data, to transfer the prescribed ports to the individual patient 3) Review and adjust the transferred port locations using the port placement visualization module. Tool maneuverability and target reachability can be tested using the visualization system. Our methodology would decrease the amount of physician input necessary to optimize port placement for each patient case. In a follow up work, we plan to use the transferred ports as starting point for further optimization of the port locations by formulating a cost function that will take into account factors such as tool dexterity and likelihood of collision between instruments.

  13. Computer aided planning for orthognatic surgery

    CERN Document Server

    Chabanas, M; Payan, Y; Boutault, F; Chabanas, Matthieu; Marecaux, Christophe; Payan, Yohan; Boutault, Franck

    2002-01-01

    A computer aided maxillofacial sequence is presented, applied to orthognatic surgery. It consists of 5 main stages: data acquisition and integration, surgical planning, surgical simulation, and per operative assistance. The planning and simulation steps are then addressed in a way that is clinically relevant. First concepts toward a 3D cephalometry are presented for a morphological analysis, surgical planning, and bone and soft tissue simulation. The aesthetic surgical outcomes of bone repositioning are studied with a biomechanical Finite Element soft tissue model.

  14. Evaluation of deformation accuracy of a virtual pneumoperitoneum method based on clinical trials for patient-specific laparoscopic surgery simulator

    Science.gov (United States)

    Oda, Masahiro; Qu, Jia Di; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Mori, Kensaku

    2012-02-01

    This paper evaluates deformation accuracy of a virtual pneumoperitoneum method by utilizing measurement data of real deformations of patient bodies. Laparoscopic surgery is an option of surgical operations that is less invasive technique as compared with traditional surgical operations. In laparoscopic surgery, the pneumoperitoneum process is performed to create a viewing and working space. Although a virtual pneumoperitoneum method based on 3D CT image deformation has been proposed for patient-specific laparoscopy simulators, quantitative evaluation based on measurements obtained in real surgery has not been performed. In this paper, we evaluate deformation accuracy of the virtual pneumoperitoneum method based on real deformation data of the abdominal wall measured in operating rooms (ORs.) The evaluation results are used to find optimal deformation parameters of the virtual pneumoperitoneum method. We measure landmark positions on the abdominal wall on a 3D CT image taken before performing a pneumoperitoneum process. The landmark positions are defined based on anatomical structure of a patient body. We also measure the landmark positions on a 3D CT image deformed by the virtual pneumoperitoneum method. To measure real deformations of the abdominal wall, we measure the landmark positions on the abdominal wall of a patient before and after the pneumoperitoneum process in the OR. We transform the landmark positions measured in the OR from the tracker coordinate system to the CT coordinate system. A positional error of the virtual pneumoperitoneum method is calculated based on positional differences between the landmark positions on the 3D CT image and the transformed landmark positions. Experimental results based on eight cases of surgeries showed that the minimal positional error was 13.8 mm. The positional error can be decreased from the previous method by calculating optimal deformation parameters of the virtual pneumoperitoneum method from the experimental

  15. Real-time surgery simulation of intracranial aneurysm clipping with patient-specific geometries and haptic feedback

    Science.gov (United States)

    Fenz, Wolfgang; Dirnberger, Johannes

    2015-03-01

    Providing suitable training for aspiring neurosurgeons is becoming more and more problematic. The increasing popularity of the endovascular treatment of intracranial aneurysms leads to a lack of simple surgical situations for clipping operations, leaving mainly the complex cases, which present even experienced surgeons with a challenge. To alleviate this situation, we have developed a training simulator with haptic interaction allowing trainees to practice virtual clipping surgeries on real patient-specific vessel geometries. By using specialized finite element (FEM) algorithms (fast finite element method, matrix condensation) combined with GPU acceleration, we can achieve the necessary frame rate for smooth real-time interaction with the detailed models needed for a realistic simulation of the vessel wall deformation caused by the clamping with surgical clips. Vessel wall geometries for typical training scenarios were obtained from 3D-reconstructed medical image data, while for the instruments (clipping forceps, various types of clips, suction tubes) we use models provided by manufacturer Aesculap AG. Collisions between vessel and instruments have to be continuously detected and transformed into corresponding boundary conditions and feedback forces, calculated using a contact plane method. After a training, the achieved result can be assessed based on various criteria, including a simulation of the residual blood flow into the aneurysm. Rigid models of the surgical access and surrounding brain tissue, plus coupling a real forceps to the haptic input device further increase the realism of the simulation.

  16. Imaging, Virtual Planning, Design, and Production of Patient-Specific Implants and Clinical Validation in Craniomaxillofacial Surgery

    OpenAIRE

    Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-M

    2012-01-01

    The purpose of this article was to describe the workflow from imaging, via virtual design, to manufacturing of patient-specific titanium reconstruction plates, cutting guide and mesh, and its utility in connection with surgical treatment of acquired bone defects in the mandible using additive manufacturing by electron beam melting (EBM). Based on computed tomography scans, polygon skulls were created. Following that virtual treatment plans entailing free microvascular transfer of fibula flaps...

  17. 3D Rapid Prototyping for Otolaryngology-Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling.

    Directory of Open Access Journals (Sweden)

    Harley H L Chan

    Full Text Available The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i a mono-material paranasal sinus phantom for endoscopy training ii a multi-material skull base simulator and iii 3D patient-specific mandible templates. Digital processing of these phantoms is based on real patient or cadaveric 3D images such as CT or MRI data. Three endoscopic sinus surgeons examined the realism of the endoscopist training phantom. One experienced endoscopic skull base surgeon conducted advanced sinus procedures on the high-fidelity multi-material skull base simulator. Ten patients participated in a prospective clinical study examining patient-specific modeling for mandibular reconstructive surgery. Qualitative feedback to assess the realism of the endoscopy training phantom and high-fidelity multi-material phantom was acquired. Conformance comparisons using assessments from the blinded reconstructive surgeons measured the geometric performance between intra-operative and pre-operative reconstruction mandible plates. Both the endoscopy training phantom and the high-fidelity multi-material phantom received positive feedback on the realistic structure of the phantom models. Results suggested further improvement on the soft tissue structure of the phantom models is necessary. In the patient-specific mandible template study, the pre-operative plates were judged by two blinded surgeons as providing optimal conformance in 7 out of 10 cases. No statistical differences were found in plate fabrication time and conformance, with pre-operative plating providing the advantage of reducing time spent in the operation room. The applicability of common model design and

  18. 9th Asian Conference on Computer-Aided Surgery

    CERN Document Server

    2016-01-01

    This book presents the latest research advances in the theory, design, control, and application of robot systems intended for a variety of purposes such as manipulation, manufacturing, automation, surgery, locomotion, and biomechanics. Several chapters deal with fundamental kinematics in nature, including synthesis, calibration, redundancy, force control, dexterity, inverse and forward kinematics, kinematic singularities, and over-constrained systems. This book is a compilation of the extended versions of the very best papers selected from the many that were presented at the Asian Conference on Computer-Aided Surgery held September 16–18, 2013, in Tokyo, Japan (ACCAS 2013).

  19. In-vivo measurement of the human soft tissues constitutive laws. Applications to Computer Aided Surgery

    CERN Document Server

    Schiavone, Patrick; Ohayon, J; Payan, Y

    2007-01-01

    In the 80's, biomechanicians were asked to work on Computer Aided Surgery applications since orthopaedic surgeons were looking for numerical tools able to predict risks of fractures. More recently, biomechanicians started to address soft tissues arguing that most of the human body is made of such tissues that can move as well as deform during surgical gestures [1]. An intra-operative use of a continuous Finite Element (FE) Model of a given tissue mainly faces two problems: (1) the numerical simulations have to be "interactive", i.e. sufficiently fast to provide results during surgery (which can be a strong issue in the context of hyperelastic models for example) and (2) during the intervention, the surgeon needs a device that can be used to provide to the model an estimation of the patient-specific constitutive behaviour of the soft tissues. This work proposes an answer to the second point, with the design of a new aspiration device aiming at characterizing the in vivo constitutive laws of human soft tissues....

  20. Decision aiding in plastic surgery: a multicriteria analysis

    Directory of Open Access Journals (Sweden)

    Luiz Flávio Autran Monteiro Gomes

    2012-08-01

    Full Text Available The aim of this article is to present, through a real case, a practical way, based on Multicriteria Decision Aiding, to support decision making in Plastic Surgery. The case studied was a Caucasian woman of 36 years of age with mammarian hypertrophia with ptosis and abdominal lipodystrophy, making it necessary to select the most adequate techniques for the best aesthetic result. For this purpose, the multicriteria methods Even Swaps and PrOACT were used. Three plastic surgeons working in the city of Rio de Janeiro with equivalent professional experience were consulted as decision agents. In order to define the objectives to be achieved, the criteria relevant to the making of the decision and the alternatives which could be used were identified. Throughout this identification and in the later analysis the surgeons participated in the application of the methods, which contributed towards facilitating their acceptance of the multicriteria analysis in their decision making. It was confirmed, in this case study, that the use of Multicriteria Decision Aiding tends to make the medical decision more wide ranging and, above all, transparent. The plastic surgeons themselves validated the analysis, considering it fully consistent with their professional experience.

  1. Computer aided surgery. Current status and future directions

    International Nuclear Information System (INIS)

    This review describes topics in the title in the order of 3D model reconstruction and therapeutic planning based on images before surgery; registration of the actual images in virtual physical space of the patient who is under surgical operation, to the preoperative ones with use of 3D-position sensor, ultrasonics, endoscopy and X-diaphanoscopy; and their accuracy analysis. Images before surgery usually obtained with CT and MR are reconstructed in 3D for the purpose of therapeutic planning by segmentation of the target organ/site, surrounding organs, bones and blood vessels. Navigation system at the surgery functions to make the images obtained before and during operation to be integrated for their registration and displaying. Usually, the optical marker and camera both equipped in the endoscope, and position sensor (tracker) are used for integration in the operation coordinate system. For this, the actual pictures at liver operation are given. For accuracy analysis there is a theory of target registration error, which has been established on FDA demands. In future, development of technology concerned in this field like that of robot, bio-dynamics, biomaterials, sensor and high performance computing together with 4D document of surgery for feed-back to technology are desirable for the systematic growing of this surgical technology. (T.I.)

  2. Biomechanics applied to computer-aided diagnosis: examples of orbital and maxillofacial surgeries

    CERN Document Server

    Payan, Y; Chabanas, M; Swider, P; Marecaux, C; Boutault, F; Payan, Yohan; Luboz, Vincent; Chabanas, Matthieu; Swider, Pascal; Marecaux, Christophe; Boutault, Franck

    2005-01-01

    This paper introduces the methodology proposed by our group to model the biological soft tissues deformations and to couple these models with Computer-Assisted Surgical (CAS) applications. After designing CAS protocols that mainly focused on bony structures, the Computer Aided Medical Imaging group of Laboratory TIMC (CNRS, France) now tries to take into account the behaviour of soft tissues in the CAS context. For this, a methodology, originally published under the name of the Mesh-Matching method, has been proposed to elaborate patient specific models. Starting from an elaborate manually-built "generic" Finite Element (FE) model of a given anatomical structure, models adapted to the geometries of each new patient ("patient specific" FE models) are automatically generated through a non-linear elastic registration algorithm. This paper presents the general methodology of the Mesh-Matching method and illustrates this process with two clinical applications, namely the orbital and the maxillofacial computer-assi...

  3. Electromagnetic tracking for abdominal interventions in computer aided surgery.

    Science.gov (United States)

    Zhang, Hui; Banovac, Filip; Lin, Ralph; Glossop, Neil; Wood, Bradford J; Lindisch, David; Levy, Elliot; Cleary, Kevin

    2006-05-01

    Electromagnetic tracking has great potential for assisting physicians in precision placement of instruments during minimally invasive interventions in the abdomen, since electromagnetic tracking is not limited by the line-of-sight restrictions of optical tracking. A new generation of electromagnetic tracking has recently become available, with sensors small enough to be included in the tips of instruments. To fully exploit the potential of this technology, our research group has been developing a computer aided, image-guided system that uses electromagnetic tracking for visualization of the internal anatomy during abdominal interventions. As registration is a critical component in developing an accurate image-guided system, we present three registration techniques: 1) enhanced paired-point registration (time-stamp match registration and dynamic registration); 2) orientation-based registration; and 3) needle shape-based registration. Respiration compensation is another important issue, particularly in the abdomen, where respiratory motion can make precise targeting difficult. To address this problem, we propose reference tracking and affine transformation methods. Finally, we present our prototype navigation system, which integrates the registration, segmentation, path-planning and navigation functions to provide real-time image guidance in the clinical environment. The methods presented here have been tested with a respiratory phantom specially designed by our group and in swine animal studies under approved protocols. Based on these tests, we conclude that our system can provide quick and accurate localization of tracked instruments in abdominal interventions, and that it offers a user-friendly display for the physician.

  4. Using a smart phone for information rendering in Computer-Aided Surgery

    OpenAIRE

    Gael, Le Bellego; Bucki, Marek; Bricault, Ivan; Troccaz, Jocelyne

    2011-01-01

    Computer-aided surgery intensively uses the concept of navigation: after having collected CT data from a patient and transferred them to the operating room coordinate system, the surgical instrument (a puncture needle for instance) is localized and its position is visualized with respect to the patient organs which are not directly visible. This approach is very similar to the GPS paradigm. Traditionally, three orthogonal slices in the patient data are presented on a distant screen. Sometimes...

  5. Does computer-aided surgical simulation improve efficiency in bimaxillary orthognathic surgery?

    Science.gov (United States)

    Schwartz, H C

    2014-05-01

    The purpose of this study was to compare the efficiency of bimaxillary orthognathic surgery using computer-aided surgical simulation (CASS), with cases planned using traditional methods. Total doctor time was used to measure efficiency. While costs vary widely in different localities and in different health schemes, time is a valuable and limited resource everywhere. For this reason, total doctor time is a more useful measure of efficiency than is cost. Even though we use CASS primarily for planning more complex cases at the present time, this study showed an average saving of 60min for each case. In the context of a department that performs 200 bimaxillary cases each year, this would represent a saving of 25 days of doctor time, if applied to every case. It is concluded that CASS offers great potential for improving efficiency when used in the planning of bimaxillary orthognathic surgery. It saves significant doctor time that can be applied to additional surgical work.

  6. Virtual Reality Aided Positioning of Mobile C-Arms for Image-Guided Surgery

    OpenAIRE

    Zhenzhou Shao; Yong Guan; Jindong Tan

    2014-01-01

    For the image-guided surgery, the positioning of mobile C-arms is a key technique to take X-ray images in a desired pose for the confirmation of current surgical outcome. Unfortunately, surgeons and patient often suffer the radiation exposure due to the repeated imaging when the X-ray image is of poor quality or not captured at a good projection view. In this paper, a virtual reality (VR) aided positioning method for the mobile C-arm is proposed by the alignment of 3D surface model of region ...

  7. Patient-Specific Computational Modeling

    CERN Document Server

    Peña, Estefanía

    2012-01-01

    This book addresses patient-specific modeling. It integrates computational modeling, experimental procedures, imagine clinical segmentation and mesh generation with the finite element method (FEM) to solve problems in computational biomedicine and bioengineering. Specific areas of interest include cardiovascular problems, ocular and muscular systems and soft tissue modeling. Patient-specific modeling has been the subject of serious research over the last seven years and interest in the area is continually growing and this area is expected to further develop in the near future.

  8. A visual-aided wireless monitoring system design for total hip replacement surgery.

    Science.gov (United States)

    Chen, Hong; Gao, Jiyang; Su, Shaojie; Zhang, Xu; Wang, Zhihua

    2015-04-01

    To improve the positioning accuracy of implants in Total Hip Replacement (THR) surgeries, a visual-aided wireless monitoring system for THR surgery is proposed in this paper. This system aims to measure and display the contact distribution and relative pose between femoral head and acetabulum prosthesis during the surgery to help surgeons obtain accurate position of implants. The system consists of two parts: the Sensors Array Measuring System (SAMS) and the display part. The SAMS is composed of a sensors array (including contact sensors and an image sensor), signal conditioning circuits, a low power microcontroller (MCU), and a low-power transceiver. The SAMS is designed to estimate the relative pose of femoral head component to acetabular component. The display part processes the data from sensors and demonstrates the contact distribution and the pose of the prothesis during the surgery in 3-D graphics. The two parts of the system communicate with each other on an RF link at the band of 400 MHz. The signal conditioning circuits have been designed and fabricated in 0.18 μm CMOS process. Testing results show that the resolution of the signal conditioning circuits is 60.1 μ Vpp (1.35 g) with ±100 mVpp input. The chip can operate under 1.2-to-3.6 V supply voltage for single battery applications with 116-160 μ A current consumption. The system has been verified by the simulation with rotation quaternion and translation vector. The experimental results show that the contact distribution and relative pose of the two components could be measured and demonstrated in real time. The relative error of rotation is less than 8% and the actual relative error of translation is less than 10%. PMID:25879970

  9. Response to comments on "Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note"

    Directory of Open Access Journals (Sweden)

    Agarwa Anil

    2008-10-01

    Full Text Available Abstract Response to comments on 'Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note' Bhagat H, Agarwal A, Sharma MS Journal of Brachial Plexus and Peripheral Nerve Injury 2008, 3:14 (22 May 2008

  10. Response to comments on "Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note"

    OpenAIRE

    Agarwa Anil; Bhagat Hemant; Sharma Manish S

    2008-01-01

    Abstract Response to comments on 'Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note' Bhagat H, Agarwal A, Sharma MS Journal of Brachial Plexus and Peripheral Nerve Injury 2008, 3:14 (22 May 2008)

  11. Evaluation of three-dimensional position change of the condylar head after orthognathic surgery using computer-aided design/computer-aided manufacturing-made condyle positioning jig.

    Science.gov (United States)

    Kim, Hyung-Mo; Baek, Seung-Hak; Kim, Tae-Yun; Choi, Jin-Young

    2014-11-01

    This study was performed to evaluate the efficacy of computer-aided design/computer-aided manufacturing (CAM/CAD)-made condyle positioning jig in orthognathic surgery. The sample consisted of 40 mandibular condyles of 20 patients with class III malocclusion who underwent bilateral sagittal split ramus osteotomy with semirigid fixation (6 men and 14 women; mean age, 25 y; mean amount of mandibular setback, 5.8 mm). Exclusion criteria were patients who needed surgical correction of the frontal ramal inclination and had signs and symptoms of the temporomandibular disorder before surgery. Three-dimensional computed tomograms were taken 1 month before the surgery (T1) and 1 day after the surgery (T2). The condylar position was evaluated at the T1 and T2 stages on the axial, frontal, and sagittal aspects in the three-dimensional coordinates. The linear change of the posterior border of the proximal segment of the ramus between T1 and T2 was also evaluated in 30 condyles (15 patients), with the exception of 10 condyles of 5 patients who received mandibular angle reduction surgery. There was no significant difference in the condylar position in the frontal and sagittal aspects (P > 0.05). Although there was a significant difference in the condylar position in the axial aspect (P < 0.01), the amount of difference was less than 1 mm and 1 degree; it can be considered clinically nonsignificant. In the linear change of the posterior border of the proximal segment of the ramus, the mean change was 1.4 mm and 60% of the samples showed a minimal change of less than 1 mm. The results of this study suggest that CAD/CAM-made condyle positioning jig is easy to install and reliable to use in orthognathic surgery.

  12. On the prospect of patient-specific biomechanics without patient-specific properties of tissues.

    Science.gov (United States)

    Miller, Karol; Lu, Jia

    2013-11-01

    This paper presents main theses of two keynote lectures delivered at Euromech Colloquium "Advanced experimental approaches and inverse problems in tissue biomechanics" held in Saint Etienne in June 2012. We are witnessing an advent of patient-specific biomechanics that will bring in the future personalized treatments to sufferers all over the world. It is the current task of biomechanists to devise methods for clinically-relevant patient-specific modeling. One of the obstacles standing before the biomechanics community is the difficulty in obtaining patient-specific properties of tissues to be used in biomechanical models. We postulate that focusing on reformulating computational mechanics problems in such a way that the results are weakly sensitive to the variation in mechanical properties of simulated continua is more likely to bear fruit in near future. We consider two types of problems: (i) displacement-zero traction problems whose solutions in displacements are weakly sensitive to mechanical properties of the considered continuum; and (ii) problems that are approximately statically determinate and therefore their solutions in stresses are also weakly sensitive to mechanical properties of constituents. We demonstrate that the kinematically loaded biomechanical models of the first type are applicable in the field of image-guided surgery where the current, intraoperative configuration of a soft organ is of critical importance. We show that sac-like membranes, which are prototypes of many thin-walled biological organs, are approximately statically determinate and therefore useful solutions for wall stress can be obtained without the knowledge of the wall's properties. We demonstrate the clinical applicability and effectiveness of the proposed methods using examples from modeling neurosurgery and intracranial aneurysms. PMID:23491073

  13. Imaging based, patient specific dosimetry

    International Nuclear Information System (INIS)

    Full text: The prognosis of achieving longtime remission for disseminated cancer disease is in many cases poor. A systemic treatment is required and therefore external beam radiation therapy is less suited. Treatment with radiolabeled pharmaceuticals, so called radionuclide therapy is such a systemic treatment. In radionuclide therapy, the absorbed dose is delivered by administration of radionuclides that emit electrons or alpha particles. It is here assumed that the released kinetic energy is transferred by interactions to sensitive parts of the cells activating cell death, and thus an accurate dosimetry is important. However, absorbed dose planning for radionuclide therapy is a real challenge in that the source cannot be turned on or off (as in external beam therapy) but decays exponentially with characteristics depending on the biokinetics and the radionuclide half-life. On a small-scale, the radiopharmaceutical is also heterogeneously distributed which means that the energy deposition is generally nonuniform. The biokinetics may also change over time which means that activity measurements need to be made at several time points to estimate the total amount of released energy in an organ or tumour. Practical issues regarding the number of measurements and patient mobility may therefore limit the accuracy in this calculation. The dose-rate for radionuclide therapy is also much lower than in external beam therapy. Since the treatment is systemic, circulating activity may result in absorbed doses to normal organs and tissues. Often this poses a problem and puts a limit on the amount of activity to can be administered. This is one of the major reasons for the requirement of an accurate patient-specific dosimetry. One of the major problems is that the biokinetics varies between patients and the activity uptake and clearance should therefore be measured for each individual patient in order to estimate the total number of decays in a particular organ/tissue. The way

  14. Patient specific stress and rupture analysis of ascending thoracic aneurysms.

    Science.gov (United States)

    Trabelsi, Olfa; Davis, Frances M; Rodriguez-Matas, Jose F; Duprey, Ambroise; Avril, Stéphane

    2015-07-16

    An ascending thoracic aortic aneurysm (ATAA) is a serious medical condition which, more often than not, requires surgery. Aneurysm diameter is the primary clinical criterion for determining when surgical intervention is necessary but, biomechanical studies have suggested that the diameter criterion is insufficient. This manuscript presents a method for obtaining the patient specific wall stress distribution of the ATAA and the retrospective rupture risk for each patient. Five human ATAAs and the preoperative dynamic CT scans were obtained during elective surgeries to replace each patient's aneurysm with a synthetic graft. The material properties and rupture stress for each tissue sample were identified using bulge inflation tests. The dynamic CT scans were used to generate patient specific geometries for a finite element (FE) model of each patient's aneurysm. The material properties from the bulge inflation tests were implemented in the FE model and the wall stress distribution at four different pressures was estimated. Three different rupture risk assessments were compared: the maximum diameter, the rupture risk index, and the overpressure index. The peak wall stress values for the patients ranged from 28% to 94% of the ATAA's failure stress. The rupture risk and overpressure indices were both only weakly correlated with diameter (ρ=-0.29, both cases). In the future, we plan to conduct a large experimental and computational study that includes asymptomatic patients under surveillance, patients undergoing elective surgery, and patients who have experienced rupture or dissection to determine if the rupture risk index or maximum diameter can meaningfully differentiate between the groups. PMID:25979384

  15. A 3D computer-aided design system applied to diagnosis and treatment planning in orthodontics and orthognathic surgery.

    Science.gov (United States)

    Motohashi, N; Kuroda, T

    1999-06-01

    The purpose of this article is to describe a newly developed 3D computer-aided design (CAD) system for the diagnostic set-up of casts in orthodontic diagnosis and treatment planning, and its preliminary clinical applications. The system comprises a measuring unit which obtains 3D information from the dental model using laser scanning, and a personal computer to generate the 3D graphics. When measuring the 3D shape of the model, to minimize blind sectors, the model is scanned from two different directions with the slit-ray laser beam by rotating the mounting angle of the model on the measuring device. For computed simulation of tooth movement, the representative planes, defined by the anatomical reference points, are formed for each individual tooth and are arranged along a guideline descriptive of the individual arch form. Subsequently, the 3D shape is imparted to each of the teeth arranged on the representative plane to form an arrangement of the 3D profile. When necessary, orthognathic surgery can be simulated by moving the mandibular dental arch three-dimensionally to establish the optimum occlusal relationship. Compared with hand-made set-up models, the computed diagnostic cast has advantages such as high-speed processing and quantitative evaluation on the amount of 3D movement of the individual tooth relative to the craniofacial plane. Trial clinical applications demonstrated that the use of this system facilitated the otherwise complicated and time-consuming mock surgery for treatment planning in orthognathic surgery.

  16. Patient-Specific Modeling in Tomorrow's Medicine

    CERN Document Server

    2012-01-01

    This book reviews the frontier of research and clinical applications of Patient Specific Modeling, and provides a state-of-the-art update as well as perspectives on future directions in this exciting field. The book is useful for medical physicists, biomedical engineers and other engineers who are interested in the science and technology aspects of Patient Specific Modeling, as well as for radiologists and other medical specialists who wish to be updated about the state of implementation.

  17. Preoperative interscalene brachial plexus block aids in perioperative temperature management during arthroscopic shoulder surgery

    Science.gov (United States)

    Lim, Se Hun; Lee, Wonjin; Park, JaeGwan; Kim, Myoung-hun; Cho, Kwangrae; Lee, Jeong Han; Cheong, Soon Ho

    2016-01-01

    Background Hypothermia is common during arthroscopic shoulder surgery under general anesthesia, and anesthetic-impaired thermoregulation is thought to be the major cause of hypothermia. This prospective, randomized, double-blind study was designed to compare perioperative temperature during arthroscopic shoulder surgery with interscalene brachial plexus block (IBPB) followed by general anesthesia vs. general anesthesia alone. Methods Patients scheduled for arthroscopic shoulder surgery were randomly allocated to receive IBPB followed by general anesthesia (group GB, n = 20) or general anesthesia alone (group GO, n = 20), and intraoperative and postoperative body temperatures were measured. Results The initial body temperatures were 36.5 ± 0.3℃ vs. 36.4 ± 0.4℃ in group GB vs. GO, respectively (P = 0.215). The body temperature at 120 minutes after induction of anesthesia was significantly higher in group GB than in group GO (35.8 ± 0.3℃ vs. 34.9 ± 0.3℃; P < 0.001). The body temperatures at 60 minutes after admission to the post-anesthesia care unit were 35.8 ± 0.3℃ vs. 35.2 ± 0.2℃ in group GB vs. GO, respectively (P < 0.001). The concentrations of desflurane at 0, 15, and 120 minutes after induction of anesthesia were 6.0 vs. 6.0% (P = 0.330), 5.0 ± 0.8% vs. 5.8 ± 0.4% (P = 0.001), and 3.4 ± 0.4% vs. 7.1 ± 0.9% (P < 0.001) in group GB vs. GO, respectively. Conclusions The present study demonstrated that preoperative IBPB could reduce both the intraoperative concentration of desflurane and the reduction in body temperature during and after arthroscopic shoulder surgery.

  18. Virtual temporal bone: an interactive 3-dimensional learning aid for cranial base surgery

    OpenAIRE

    Kockro, R A; Hwang, P Y

    2009-01-01

    OBJECTIVE: We have developed an interactive virtual model of the temporal bone for the training and teaching of cranial base surgery. METHODS: The virtual model was based on the tomographic data of the Visible Human Project. The male Visible Human's computed tomographic data were volumetrically reconstructed as virtual bone tissue, and the individual photographic slices provided the basis for segmentation of the middle and inner ear structures, cranial nerves, vessels, and brainstem. These st...

  19. Perforation of the bowel due to cytomegalovirus infection in a man with AIDS: surgery is not always necessary!

    Science.gov (United States)

    Yoganathan, Katie Tharshana; Morgan, Andrew Roger; Yoganathan, Kathir G

    2016-01-01

    Cytomegalovirus (CMV) infection is the most common viral opportunistic infection in immunocompromised patients and is a rare cause of bowel perforation. It invariably requires surgical intervention and is often fatal. We report a 50-year-old Caucasian man with AIDS, presented 3 weeks after developing abdominal pain and distension. He was treated for CMV retinitis in the past. His adherence to antiretroviral therapy was poor. Examination revealed a recurrence of active CMV retinitis. His abdomen was tender and distended. The plain X-ray of the abdomen revealed a double wall sign (Rigler's sign), indicating pneumoperitoneum due to the bowel perforation. The upper endoscopy was normal. His CD4 count was 30 cells/mm(3) He was treated with cidofovir infusion. He made a full recovery, without requiring any form of surgery. However, he died of adult respiratory distress syndrome 14 months later, due to iatrogenic acute pancreatitis. PMID:27440845

  20. A web-based computer aided system for liver surgery planning: initial implementation on RayPlus

    Science.gov (United States)

    Luo, Ming; Yuan, Rong; Sun, Zhi; Li, Tianhong; Xie, Qingguo

    2016-03-01

    At present, computer aided systems for liver surgery design and risk evaluation are widely used in clinical all over the world. However, most systems are local applications that run on high-performance workstations, and the images have to processed offline. Compared with local applications, a web-based system is accessible anywhere and for a range of regardless of relative processing power or operating system. RayPlus (http://rayplus.life.hust.edu.cn), a B/S platform for medical image processing, was developed to give a jump start on web-based medical image processing. In this paper, we implement a computer aided system for liver surgery planning on the architecture of RayPlus. The system consists of a series of processing to CT images including filtering, segmentation, visualization and analyzing. Each processing is packaged into an executable program and runs on the server side. CT images in DICOM format are processed step by to interactive modeling on browser with zero-installation and server-side computing. The system supports users to semi-automatically segment the liver, intrahepatic vessel and tumor from the pre-processed images. Then, surface and volume models are built to analyze the vessel structure and the relative position between adjacent organs. The results show that the initial implementation meets satisfactorily its first-order objectives and provide an accurate 3D delineation of the liver anatomy. Vessel labeling and resection simulation are planned to add in the future. The system is available on Internet at the link mentioned above and an open username for testing is offered.

  1. Morphing patient-specific musculoskeletal models

    DEFF Research Database (Denmark)

    Rasmussen, John; Galibarov, Pavel E.; Al-Munajjed, Amir;

    Anatomically realistic musculoskeletal models tend to be very complicated. The current full-body model of the AnyScript Model Repository comprises more than 1000 individually activated muscles and hundreds of bones and joints, and the development of these generic body parts represents an investment...... of dozens of man-years. Healthy humans differ significantly in size, shape and general morphology, and this variation is even larger for patients with pathological anatomies. Thus, patient-specific models are imperative for reliable biomechanical analyses on which decisions of surgical treatments...... (ii). The morphing is subsequently used to transform parts of the generic musculoskeletal model to a patient-specific version, thus changing bone shapes, muscle insertion points, joint locations and other geometrical properties. Research questions include how to select point sets and whether...

  2. Patient-Specific Surgical Planning, Where Do We Stand? The Example of the Fontan Procedure.

    Science.gov (United States)

    de Zélicourt, Diane A; Kurtcuoglu, Vartan

    2016-01-01

    The Fontan surgery for single ventricle heart defects is a typical example of a clinical intervention in which patient-specific computational modeling can improve patient outcome: with the functional heterogeneity of the presenting patients, which precludes generic solutions, and the clear influence of the surgically-created Fontan connection on hemodynamics, it is acknowledged that individualized computational optimization of the post-operative hemodynamics can be of clinical value. A large body of literature has thus emerged seeking to provide clinically relevant answers and innovative solutions, with an increasing emphasis on patient-specific approaches. In this review we discuss the benefits and challenges of patient-specific simulations for the Fontan surgery, reviewing state of the art solutions and avenues for future development. We first discuss the clinical impact of patient-specific simulations, notably how they have contributed to our understanding of the link between Fontan hemodynamics and patient outcome. This is followed by a survey of methodologies for capturing patient-specific hemodynamics, with an emphasis on the challenges of defining patient-specific boundary conditions and their extension for prediction of post-operative outcome. We conclude with insights into potential future directions, noting that one of the most pressing issues might be the validation of the predictive capabilities of the developed framework. PMID:26183962

  3. On the prospect of patient-specific biomechanics without patient-specific properties of tissues

    OpenAIRE

    Miller, Karol; Lu, Jia

    2013-01-01

    This paper presents main theses of two keynote lectures delivered at Euromech Colloquium “Advanced experimental approaches and inverse problems in tissue biomechanics” held in Saint Etienne in June 2012. We are witnessing an advent of patient-specific biomechanics that will bring in the future personalized treatments to sufferers all over the world. It is the current task of biomechanists to devise methods for clinically-relevant patient-specific modeling. One of the obstacles standing before...

  4. The migration of femoral components after total hip replacement surgery: accuracy and precision of software-aided measurements

    Energy Technology Data Exchange (ETDEWEB)

    Decking, J. [Dept. of Orthopaedic Surgery, Univ. of Mainz School of Medicine, Mainz (Germany); Schuetz, U.; Decking, R.; Puhl, W. [Orthopaedic Dept., Univ. of Ulm, School of Medicine (Germany)

    2003-09-01

    Objective: To assess the accuracy and precision of a software-aided system to measure migration of femoral components after total hip replacement (THR) on digitised radiographs. Design and patients: Subsidence and varus-valgus tilt of THR stems within the femur were measured on digitised anteroposterior pelvic radiographs. The measuring software (UMA, GEMED, Germany) relies on bony landmarks and comparability parameters of two consecutive radiographs. Its accuracy and precision were calculated by comparing it with the gold standard in migration measurements, radiostereometric analysis (RSA). Radiographs and corresponding RSA measurements were performed in 60 patients (38-69 years) following cementless THR surgery. Results and conclusions: The UMA software measured the subsidence of the stems with an accuracy of {+-}2.5 mm and varus-valgus tilt with an accuracy of {+-}1.8 (95% confidence interval). A good interobserver and intraobserver reliability was calculated with Cronbach's alpha ranging from 0.86 to 0.97. Measuring the subsidence of THR stems within the femur is an important parameter in the diagnosis of implant loosening. Software systems such as UMA improve the accuracy of migration measurements and are easy to use on routinely performed radiographs of operated hip joints. (orig.)

  5. Algorithm for planning a double-jaw orthognathic surgery using a computer-aided surgical simulation (CASS) protocol. Part 1: planning sequence.

    Science.gov (United States)

    Xia, J J; Gateno, J; Teichgraeber, J F; Yuan, P; Chen, K-C; Li, J; Zhang, X; Tang, Z; Alfi, D M

    2015-12-01

    The success of craniomaxillofacial (CMF) surgery depends not only on the surgical techniques, but also on an accurate surgical plan. The adoption of computer-aided surgical simulation (CASS) has created a paradigm shift in surgical planning. However, planning an orthognathic operation using CASS differs fundamentally from planning using traditional methods. With this in mind, the Surgical Planning Laboratory of Houston Methodist Research Institute has developed a CASS protocol designed specifically for orthognathic surgery. The purpose of this article is to present an algorithm using virtual tools for planning a double-jaw orthognathic operation. This paper will serve as an operation manual for surgeons wanting to incorporate CASS into their clinical practice.

  6. Patient specific modelling in diagnosing depression

    DEFF Research Database (Denmark)

    Ottesen, Johnny T.

    2015-01-01

    Depression is a very common disease. Approximately 10% of people in the Western world experience severe depression during their lifetime and many more experience a mild form of depression. It is commonly believed that depression is caused by malfunctions in the biological system constituted by the...... hypothalamus-pituitary-adrenal (HPA) axis. We pose a novel model capable of showing both circardian as well as ultradian oscillations of hormone concentrations. We show that these patterns imitate those observed in the corresponding data. We demonstrate that patient-specific modelling shows its ability to make...

  7. Patient-specific simulation of tidal breathing

    Science.gov (United States)

    Walters, M.; Wells, A. K.; Jones, I. P.; Hamill, I. S.; Veeckmans, B.; Vos, W.; Lefevre, C.; Fetitia, C.

    2016-03-01

    Patient-specific simulation of air flows in lungs is now straightforward using segmented airways trees from CT scans as the basis for Computational Fluid Dynamics (CFD) simulations. These models generally use static geometries, which do not account for the motion of the lungs and its influence on important clinical indicators, such as airway resistance. This paper is concerned with the simulation of tidal breathing, including the dynamic motion of the lungs, and the required analysis workflow. Geometries are based on CT scans obtained at the extremes of the breathing cycle, Total Lung Capacity (TLC) and Functional Residual Capacity (FRC). It describes how topologically consistent geometries are obtained at TLC and FRC, using a `skeleton' of the network of airway branches. From this a 3D computational mesh which morphs between TLC and FRC is generated. CFD results for a number of patient-specific cases, healthy and asthmatic, are presented. Finally their potential use in evaluation of the progress of the disease is discussed, focusing on an important clinical indicator, the airway resistance.

  8. Toward patient-specific articular contact mechanics.

    Science.gov (United States)

    Ateshian, Gerard A; Henak, Corinne R; Weiss, Jeffrey A

    2015-03-18

    The mechanics of contacting cartilage layers is fundamentally important to understanding the development, homeostasis and pathology of diarthrodial joints. Because of the highly nonlinear nature of both the materials and the contact problem itself, numerical methods such as the finite element method are typically incorporated to obtain solutions. Over the course of five decades, we have moved from an initial qualitative understanding of articular cartilage material behavior to the ability to perform complex, three-dimensional contact analysis, including multiphasic material representations. This history includes the development of analytical and computational contact analysis methods that now provide the ability to perform highly nonlinear analyses. Numerical implementations of contact analysis based on the finite element method are rapidly advancing and will soon enable patient-specific analysis of joint contact mechanics using models based on medical image data. In addition to contact stress on the articular surfaces, these techniques can predict variations in strain and strain through the cartilage layers, providing the basis to predict damage and failure. This opens up exciting areas for future research and application to patient-specific diagnosis and treatment planning applied to a variety of pathologies that affect joint function and cartilage homeostasis.

  9. Correspondence in relation to the case report "Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note." published in May issue of Journal of Brachial Plexus and Peripheral Nerve Injury

    OpenAIRE

    Bhakta Pradipta

    2008-01-01

    Abstract Comment on 'Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note' Bhagat H, Agarwal A, Sharma MS Journal of Brachial Plexus and Peripheral Nerve Injury 2008, 3:14 (22 May 2008)

  10. COMPARATIVE ANALYSIS OF THE PATIENTS' SATISFACTION LEVEL BY MEDICAL AID QUALITY IN PRIMARY HEALTHCARE AND PLASTIC SURGERY SERVICE

    OpenAIRE

    Ganshin Igor Borisovich

    2013-01-01

    Satisfaction of patient is one of main parts of medical aid quality declared by WHO. Questionnaire of patients can elucidate mechanism of satisfaction from medical aid quality formed during treatment communication. Estimation of received information permits to compare different hospital activities and know image of medical aid created by patient's mention. Science results can be used to support management decision for choice of activities providing the higher quality signs of medical aid.

  11. Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

    Science.gov (United States)

    Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

    2015-03-01

    Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

  12. From Patient-Specific Mathematical Neuro-Oncology to Precision Medicine

    Directory of Open Access Journals (Sweden)

    Anne eBaldock

    2013-04-01

    Full Text Available Gliomas are notoriously aggressive, malignant brain tumors that have variable response to treatment. These patients often have poor prognosis, informed primarily by histopathology. Mathematical neuro-oncology (MNO is a young and burgeoning field that leverages mathematical models to predict and quantify response to therapies. These mathematical models can form the basis of modern precision medicine approaches to tailor therapy in a patient-specific manner. Patient specific models (PSMs can be used to overcome imaging limitations, improve prognostic predictions, stratify patients and assess treatment response in silico. The information gleaned from such models can aid in the construction and efficacy of clinical trials and treatment protocols, accelerating the pace of clinical research in the war on cancer. This review focuses on the growing translation of PSM to clinical neuro-oncology. It will also provide a forward-looking view on a new era of patient-specific mathematical neuro-oncology.

  13. Additive manufacturing of patient-specific tubular continuum manipulators

    Science.gov (United States)

    Amanov, Ernar; Nguyen, Thien-Dang; Burgner-Kahrs, Jessica

    2015-03-01

    Tubular continuum robots, which are composed of multiple concentric, precurved, elastic tubes, provide more dexterity than traditional surgical instruments at the same diameter. The tubes can be precurved such that the resulting manipulator fulfills surgical task requirements. Up to now the only material used for the component tubes of those manipulators is NiTi, a super-elastic shape-memory alloy of nickel and titan. NiTi is a cost-intensive material and fabrication processes are complex, requiring (proprietary) technology, e.g. for shape setting. In this paper, we evaluate component tubes made of 3 different thermoplastic materials (PLA, PCL and nylon) using fused filament fabrication technology (3D printing). This enables quick and cost-effective production of custom, patient-specific continuum manipulators, produced on site on demand. Stress-strain and deformation characteristics are evaluated experimentally for 16 fabricated tubes of each thermoplastic with diameters and shapes equivalent to those of NiTi tubes. Tubes made of PCL and nylon exhibit properties comparable to those made of NiTi. We further demonstrate a tubular continuum manipulator composed of 3 nylon tubes in a transnasal, transsphenoidal skull base surgery scenario in vitro.

  14. Skin Biopsy and Patient-Specific Stem Cell Lines

    Science.gov (United States)

    Li, Yao; Nguyen, Huy V.; Tsang, Stephen H.

    2016-01-01

    The generation of patient-specific induced pluripotent stem (iPS) cells permits the development of next-generation patient-specific systems biology models reflecting personalized genomics profiles to better understand pathophysiology. In this chapter, we describe how to create a patient-specific iPS cell line. There are three major steps: (1) performing a skin biopsy procedure on the patient; (2) extracting human fibroblast cells from the skin biopsy tissue; and (3) reprogramming patient-specific fibroblast cells into the pluripotent stem cell stage. PMID:26141312

  15. Rapid prototyping for patient-specific surgical orthopaedics guides: A systematic literature review.

    Science.gov (United States)

    Popescu, Diana; Laptoiu, Dan

    2016-06-01

    There has been a lot of hype surrounding the advantages to be gained from rapid prototyping processes in a number of fields, including medicine. Our literature review aims objectively to assess how effective patient-specific surgical guides manufactured using rapid prototyping are in a number of orthopaedic surgical applications. To this end, we carried out a systematic review to identify and analyse clinical and experimental literature studies in which rapid prototyping patient-specific surgical guides are used, focusing especially on those that entail quantifiable outcomes and, at the same time, providing details on the guides' design and type of manufacturing process. Here, it should be mentioned that in this field there are not yet medium- or long-term data, and no information on revisions. In the reviewed studies, the reported positive opinions on the use of rapid prototyping patient-specific surgical guides relate to the following main advantages: reduction in operating times, low costs and improvements in the accuracy of surgical interventions thanks to guides' personalisation. However, disadvantages and sources of errors which can cause patient-specific surgical guide failures are as well discussed by authors. Stereolithography is the main rapid prototyping process employed in these applications although fused deposition modelling or selective laser sintering processes can also satisfy the requirements of these applications in terms of material properties, manufacturing accuracy and construction time. Another of our findings was that individualised drill guides for spinal surgery are currently the favourite candidates for manufacture using rapid prototyping. Other emerging applications relate to complex orthopaedic surgery of the extremities: the forearm and foot. Several procedures such as osteotomies for radius malunions or tarsal coalition could become standard, thanks to the significant assistance provided by rapid prototyping patient-specific surgical

  16. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    OpenAIRE

    Paoli Alessandro; Barone Sandro; Chessa Giacomo; Frisardi Gianni; Razionale Armando; Frisardi Flavio

    2011-01-01

    Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgi...

  17. A review of rapid prototyped surgical guides for patient-specific total knee replacement.

    Science.gov (United States)

    Krishnan, S P; Dawood, A; Richards, R; Henckel, J; Hart, A J

    2012-11-01

    Improvements in the surgical technique of total knee replacement (TKR) are continually being sought. There has recently been interest in three-dimensional (3D) pre-operative planning using magnetic resonance imaging (MRI) and CT. The 3D images are increasingly used for the production of patient-specific models, surgical guides and custom-made implants for TKR. The users of patient-specific instrumentation (PSI) claim that they allow the optimum balance of technology and conventional surgery by reducing the complexity of conventional alignment and sizing tools. In this way the advantages of accuracy and precision claimed by computer navigation techniques are achieved without the disadvantages of additional intra-operative inventory, new skills or surgical time. This review describes the terminology used in this area and debates the advantages and disadvantages of PSI.

  18. Correspondence in relation to the case report "Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note." published in May issue of Journal of Brachial Plexus and Peripheral Nerve Injury

    Directory of Open Access Journals (Sweden)

    Bhakta Pradipta

    2008-10-01

    Full Text Available Abstract Comment on 'Capnography as an aid in localizing the phrenic nerve in brachial plexus surgery. Technical note' Bhagat H, Agarwal A, Sharma MS Journal of Brachial Plexus and Peripheral Nerve Injury 2008, 3:14 (22 May 2008

  19. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    Directory of Open Access Journals (Sweden)

    Paoli Alessandro

    2011-02-01

    Full Text Available Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast and preoperative (radiographic template models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.

  20. Study on hemodynamics in patient-specific thoracic aortic aneurysm

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The objective of this study is to investigate the hemodynamics in patient-specific thoracic aortic aneurysm and discuss the reason for formation of aortic plaque.A 3-Dimensional pulsatile blood flow in thoracic aorta with a fusiform aneurysm and 3 main branched vessels was studied numerically with the average Reynolds number of 1399 and the Womersley number of 19.2.Based on the clinical 2-Dimensional CT slice data,the patient-specific geometry model was constructed using medical image process software.Un...

  1. Measurement properties of patient-specific instruments measuring physical function.

    NARCIS (Netherlands)

    Barten, J.A.; Pisters, M.F.; Huisman, P.A.; Takken, T.; Veenhof, C.

    2012-01-01

    Objective: To identify patient-specific self-assessment instruments, which measure physical function in patients with musculoskeletal disorders and to evaluate the descriptive properties and the psychometric qualities of these instruments. Study Design and Setting: After a systematic search, include

  2. A patient-specific scatter artifacts correction method

    OpenAIRE

    Zhao, Wei; Brunner, Stephen; NIU, KAI; Schafer, Sebastian; Royalty, Kevin; Chen, Guang-Hong

    2015-01-01

    This paper provides a fast and patient-specific scatter artifact correction method for cone-beam computed tomography (CBCT) used in image-guided interventional procedures. Due to increased irradiated volume of interest in CBCT imaging, scatter radiation has increased dramatically compared to 2D imaging, leading to a degradation of image quality. In this study, we propose a scatter artifact correction strategy using an analytical convolution-based model whose free parameters are estimated usin...

  3. Patient specific tube current modulation for CT dose reduction

    Science.gov (United States)

    Jin, Yannan; Yin, Zhye; Yao, Yangyang; Wang, Hui; Wu, Mingye; Kalra, Mannudeep; De Man, Bruno

    2015-03-01

    Radiation exposure during CT imaging has drawn growing concern from academia, industry as well as the general public. Sinusoidal tube current modulation has been available in most commercial products and used routinely in clinical practice. To further exploit the potential of tube current modulation, Sperl et al. proposed a Computer-Assisted Scan Protocol and Reconstruction (CASPAR) scheme [6] that modulates the tube current based on the clinical applications and patient specific information. The purpose of this study is to accelerate the CASPAR scheme to make it more practical for clinical use and investigate its dose benefit for different clinical applications. The Monte Carlo simulation in the original CASPAR scheme was substituted by the dose reconstruction to accelerate the optimization process. To demonstrate the dose benefit, we used the CATSIM package generate the projection data and perform standard FDK reconstruction. The NCAT phantom at thorax position was used in the simulation. We chose three clinical cases (routine chest scan, coronary CT angiography with and without breast avoidance) and compared the dose level with different mA modulation schemes (patient specific, sinusoidal and constant mA) with matched image quality. The simulation study of three clinical cases demonstrated that the patient specific mA modulation could significantly reduce the radiation dose compared to sinusoidal modulation. The dose benefits depend on the clinical application and object shape. With matched image quality, for chest scan the patient specific mA profile reduced the dose by about 15% compared to the sinusoid mA modulation; for the organ avoidance scan the dose reduction to the breast was over 50% compared to the constant mA baseline.

  4. Measurement properties of patient-specific instruments measuring physical function.

    OpenAIRE

    Barten, J.A.; Pisters, M.F.; Huisman, P.A.; Takken, T; Veenhof, C.

    2012-01-01

    Objective: To identify patient-specific self-assessment instruments, which measure physical function in patients with musculoskeletal disorders and to evaluate the descriptive properties and the psychometric qualities of these instruments. Study Design and Setting: After a systematic search, included instruments were evaluated psychometrically by the checklist “quality criteria for measurement properties of health status instruments.” Results: Twenty-three studies were included, referring to ...

  5. Feasibility of patient specific aortic blood flow CFD simulation.

    Science.gov (United States)

    Svensson, Johan; Gårdhagen, Roland; Heiberg, Einar; Ebbers, Tino; Loyd, Dan; Länne, Toste; Karlsson, Matts

    2006-01-01

    Patient specific modelling of the blood flow through the human aorta is performed using computational fluid dynamics (CFD) and magnetic resonance imaging (MRI). Velocity patterns are compared between computer simulations and measurements. The workflow includes several steps: MRI measurement to obtain both geometry and velocity, an automatic levelset segmentation followed by meshing of the geometrical model and CFD setup to perform the simulations follwed by the actual simulations. The computational results agree well with the measured data. PMID:17354898

  6. 耳显微外科和耳神经外科手术中计算机辅助外科技术的应用%Computer-aided surgery introduced for assisting otologic and neurotologic surgery

    Institute of Scientific and Technical Information of China (English)

    刘晶; 谭长强

    2012-01-01

    目的:初步探讨计算机辅助外科(CAS)技术即导航外科技术在耳显微外科及耳神经外科手术中的应用.方法:选择2例手术患者,分别行经颅中窝(MCF)径路前庭神经雪旺细胞瘤切除术和耳蜗下径路岩尖囊肿引流术,术前计算机编程和确定标记(基准标点),术中应用CAS技术辅助引导手术路径.结果:CAS技术可缩短MCF手术中颞骨解剖定位所需时间.由于将参照弓直接固定于颅骨,在整个手术过程中增加了系统的准确性和稳定性,即使患者偶然移动亦不受影响.当岩尖囊肿位置非常深、耳蜗下气房发育不良时,采用CAS技术非常有帮助.结论:在颞骨外科中CAS技术的主要优势是快速、准确的解剖定向,最重要的是缩短了手术时间和避免了一些并发症,然而CAS技术不能替代经验、解剖知识和外科判断力.%Objective; To explore application of the computer-aided surgery (CAS) , namely the surgical navigation technique, in Otomicrosurgery and ear neurosurgery. Methods; 2 cases respectively underwent vestibular nerve schwann cells tumor resection through the middle cranial fossa ( MCF) approach and petrous apex cyst treated via subcochlear drainage. Preoperative computer programming and benchmark punctuation along with the application of CAS during the operation could guide the surgical route. Results; CAS reduced the time needed for anatomic localization of the temporal bone. Because the refer bow was directly fixed on the skull, the accuracy and stability of the system were better throughout the whole operating process. Even through patients occasionally move, location accuracy was not affected. If petrous apex cyst is located very deep with mastoid air cell dysplasia, CAS might be very useful for draining by under-cochlear approach. Conclusion; The main advantage of CAS in the temporal bone surgery is rapid and accurate in anatomy orientation, which can shorten operation time and avoid some

  7. Patient specific 3D printed phantom for IMRT quality assurance

    International Nuclear Information System (INIS)

    The purpose of this study was to test the feasibility of a patient specific phantom for patient specific dosimetric verification. Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. Calculated and measured dose in the anthropomorphic phantom and the 3D printed phantom was compared for a parallel-opposed head and neck field geometry to establish tissue equivalence. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom as well as traditional standard phantoms. The maximum difference in calculated dose was 1.8% for the parallel-opposed configuration. Passing rates of various dosimetric parameters were compared for the IMRT plan measurements; the 3D printed phantom results showed greater disagreement at superficial depths than other methods. A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine use. (paper)

  8. [Robotic surgery].

    Science.gov (United States)

    Moreno-Portillo, Mucio; Valenzuela-Salazar, Carlos; Quiroz-Guadarrama, César David; Pachecho-Gahbler, Carlos; Rojano-Rodríguez, Martín

    2014-12-01

    Medicine has experienced greater scientific and technological advances in the last 50 years than in the rest of human history. The article describes relevant events, revises concepts and advantages and clinical applications, summarizes published clinical results, and presents some personal reflections without giving dogmatic conclusions about robotic surgery. The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) defines robotic surgery as a surgical procedure using technology to aid the interaction between surgeon and patient. The objective of the surgical robot is to correct human deficiencies and improve surgical skills. The capacity of repeating tasks with precision and reproducibility has been the base of the robot´s success. Robotic technology offers objective and measurable advantages: - Improving maneuverability and physical capacity during surgery. - Correcting bad postural habits and tremor. - Allowing depth perception (3D images). - Magnifying strength and movement limits. - Offering a platform for sensors, cameras, and instruments. Endoscopic surgery transformed conceptually the way of practicing surgery. Nevertheless in the last decade, robotic assisted surgery has become the next paradigm of our era. PMID:25643879

  9. An immersed-boundary framework for patient-specific optimization of inhaled drug delivery

    Science.gov (United States)

    Nicolaou, Laura; Zaki, Tamer

    2014-11-01

    Predictive numerical simulations have the potential to significantly enhance therapies for lung disease by providing a valuable clinical aid and a platform to optimize drug delivery. A difficult challenge, however, is the influence of inter-subject variations of the airway geometries and their impact on the airflow and aerosol deposition. A personalized approach to the treatment of respiratory diseases is therefore required. An in silico framework for patient-specific predictions of the flow and aerosol deposition in the respiratory airways is presented. The approach efficiently accommodates geometric variation and airway motion in order to optimize pulmonary drug delivery. A non-rigid registration method is adopted to construct dynamic airway models conforming to the patient's breathing. Accurate predictions of the flow in realistic airway geometries are computed using direct numerical simulations (DNS) with boundary conditions enforced using a robust, implicit immersed boundary (IB) method for curvilinear meshes. A Lagrangian particle-tracking scheme is adopted to model the transport and deposition of the aerosol particles in the airways. Examples of flow and aerosol deposition in realistic extrathoracic airways and of a patient-specific dynamic lung model are presented.

  10. Patient-specific modeling of human cardiovascular system elements

    Science.gov (United States)

    Kossovich, Leonid Yu.; Kirillova, Irina V.; Golyadkina, Anastasiya A.; Polienko, Asel V.; Chelnokova, Natalia O.; Ivanov, Dmitriy V.; Murylev, Vladimir V.

    2016-03-01

    Object of study: The research is aimed at development of personalized medical treatment. Algorithm was developed for patient-specific surgical interventions of the cardiovascular system pathologies. Methods: Geometrical models of the biological objects and initial and boundary conditions were realized by medical diagnostic data of the specific patient. Mechanical and histomorphological parameters were obtained with the help mechanical experiments on universal testing machine. Computer modeling of the studied processes was conducted with the help of the finite element method. Results: Results of the numerical simulation allowed evaluating the physiological processes in the studied object in normal state, in presence of different pathologies and after different types of surgical procedures.

  11. A population of patient-specific adult acquired flatfoot deformity models before and after surgery.

    Science.gov (United States)

    Spratley, E M; Matheis, E A; Hayes, C W; Adelaar, R S; Wayne, J S

    2014-09-01

    Following IRB approval, a cohort of 3-D rigid-body computational models was created from submillimeter MRIs of clinically diagnosed Adult Acquired Flatfoot Deformity patients and employed to investigate postoperative foot/ankle function and surgical effect during single-leg stance. Models were constrained through physiologic joint contact, passive soft-tissue tension, active muscle force, full body weight, and without idealized joints. Models were validated against patient-matched controls using clinically utilized radiographic angle and distance measures and plantar force distributions in the medial forefoot, lateral forefoot, and hindfoot. Each model further predicted changes in strain for the spring ligament, deltoid ligament, and plantar fascia, as well as joint contact loads for three midfoot joints, the talonavicular, navicular-1st cuneiform, and calcaneocuboid. Radiographic agreement ranged across measures, with average absolute deviations of <5° and <4 mm indicating generally good agreement. Postoperative plantar force loading in patients and models was reduced for the medial forefoot and hindfoot concomitant with increases in the lateral forefoot. Model predicted reductions in medial soft-tissue strain and increases in lateral joint contact load were consistent with in vitro observations and elucidate the biomechanical mechanisms of repair. Thus, validated rigid-body models offer promise for the investigation of foot/ankle kinematics and biomechanical behaviors that are difficult to measure in vivo.

  12. Mutirão de cirurgias de adenotonsilectomias: uma solução viável? Adeno-tonsillectomy surgery in a joint aid effort: a feasible solution ?

    Directory of Open Access Journals (Sweden)

    Marcos Luiz Antunes

    2007-08-01

    for public hospitals, and to compare the incidence of post-operative hemorrhage in joint aid effort surgery with that of regular surgeriy. METHODS: A clinical case-control prospective study of adenotonsillectomies done in joint aid efforts was done from September 2004 to June 2006 at the Diadema State Hospital. An analysis was made of the multiprofessional staff involved in this process, and a comparison was made of the incidence of hemorrhage in joint aid efforts and after regular surgery. RESULTS: 22 joint aid effort events for adenotonsillectomies were done during the period mentioned above (339 surgeries, an average 15.4 surgeries per event. The rate of postoperative hemorrhage requiring surgical revision was 1.48%(5/339, which did not differ statistically from the case-control group (1.37% - 5/364. CONCLUSION: We were able to standardize the results of adenotonsillectomies done in a joint aid effort to the parameters that are considered as safe. This may reduce the waiting line for this procedure. The difference in the incidence of postoperative hemorrhage in the joint aid effort and regular surgery was not statistically significant.

  13. Patient-Specific Pluripotent Stem Cells in Neurological Diseases

    Directory of Open Access Journals (Sweden)

    Serpen Durnaoglu

    2011-01-01

    Full Text Available Many human neurological diseases are not currently curable and result in devastating neurologic sequelae. The increasing availability of induced pluripotent stem cells (iPSCs derived from adult human somatic cells provides new prospects for cellreplacement strategies and disease-related basic research in a broad spectrum of human neurologic diseases. Patient-specific iPSC-based modeling of neurogenetic and neurodegenerative diseases is an emerging efficient tool for in vitro modeling to understand disease and to screen for genes and drugs that modify the disease process. With the exponential increase in iPSC research in recent years, human iPSCs have been successfully derived with different technologies and from various cell types. Although there remain a great deal to learn about patient-specific iPSC safety, the reprogramming mechanisms, better ways to direct a specific reprogramming, ideal cell source for cellular grafts, and the mechanisms by which transplanted stem cells lead to an enhanced functional recovery and structural reorganization, the discovery of the therapeutic potential of iPSCs offers new opportunities for the treatment of incurable neurologic diseases. However, iPSC-based therapeutic strategies need to be thoroughly evaluated in preclinical animal models of neurological diseases before they can be applied in a clinical setting.

  14. Patient-Specific Airway Wall Remodeling in Chronic Lung Disease.

    Science.gov (United States)

    Eskandari, Mona; Kuschner, Ware G; Kuhl, Ellen

    2015-10-01

    Chronic lung disease affects more than a quarter of the adult population; yet, the mechanics of the airways are poorly understood. The pathophysiology of chronic lung disease is commonly characterized by mucosal growth and smooth muscle contraction of the airways, which initiate an inward folding of the mucosal layer and progressive airflow obstruction. Since the degree of obstruction is closely correlated with the number of folds, mucosal folding has been extensively studied in idealized circular cross sections. However, airflow obstruction has never been studied in real airway geometries; the behavior of imperfect, non-cylindrical, continuously branching airways remains unknown. Here we model the effects of chronic lung disease using the nonlinear field theories of mechanics supplemented by the theory of finite growth. We perform finite element analysis of patient-specific Y-branch segments created from magnetic resonance images. We demonstrate that the mucosal folding pattern is insensitive to the specific airway geometry, but that it critically depends on the mucosal and submucosal stiffness, thickness, and loading mechanism. Our results suggests that patient-specific airway models with inherent geometric imperfections are more sensitive to obstruction than idealized circular models. Our models help to explain the pathophysiology of airway obstruction in chronic lung disease and hold promise to improve the diagnostics and treatment of asthma, bronchitis, chronic obstructive pulmonary disease, and respiratory failure. PMID:25821112

  15. A parameter estimation framework for patient-specific hemodynamic computations

    Science.gov (United States)

    Itu, Lucian; Sharma, Puneet; Passerini, Tiziano; Kamen, Ali; Suciu, Constantin; Comaniciu, Dorin

    2015-01-01

    We propose a fully automated parameter estimation framework for performing patient-specific hemodynamic computations in arterial models. To determine the personalized values of the windkessel models, which are used as part of the geometrical multiscale circulation model, a parameter estimation problem is formulated. Clinical measurements of pressure and/or flow-rate are imposed as constraints to formulate a nonlinear system of equations, whose fixed point solution is sought. A key feature of the proposed method is a warm-start to the optimization procedure, with better initial solution for the nonlinear system of equations, to reduce the number of iterations needed for the calibration of the geometrical multiscale models. To achieve these goals, the initial solution, computed with a lumped parameter model, is adapted before solving the parameter estimation problem for the geometrical multiscale circulation model: the resistance and the compliance of the circulation model are estimated and compensated. The proposed framework is evaluated on a patient-specific aortic model, a full body arterial model, and multiple idealized anatomical models representing different arterial segments. For each case it leads to the best performance in terms of number of iterations required for the computational model to be in close agreement with the clinical measurements.

  16. Robotic surgery

    Science.gov (United States)

    Robot-assisted surgery; Robotic-assisted laparoscopic surgery; Laparoscopic surgery with robotic assistance ... Robotic surgery is similar to laparoscopic surgery. It can be performed through smaller cuts than open surgery. ...

  17. A patient-specific scatter artifacts correction method

    CERN Document Server

    Zhao, Wei; Niu, Kai; Schafer, Sebastian; Royalty, Kevin; Chen, Guang-Hong

    2015-01-01

    This paper provides a fast and patient-specific scatter artifact correction method for cone-beam computed tomography (CBCT) used in image-guided interventional procedures. Due to increased irradiated volume of interest in CBCT imaging, scatter radiation has increased dramatically compared to 2D imaging, leading to a degradation of image quality. In this study, we propose a scatter artifact correction strategy using an analytical convolution-based model whose free parameters are estimated using a rough estimation of scatter profiles from the acquired cone-beam projections. It was evaluated using Monte Carlo simulations with both monochromatic and polychromatic X-ray sources. The results demonstrated that the proposed method significantly reduced the scatter-induced shading artifacts and recovered CT numbers.

  18. A patient-specific scatter artifacts correction method

    Science.gov (United States)

    Zhao, Wei; Brunner, Stephen; Niu, Kai; Schafer, Sebastian; Royalty, Kevin; Chen, Guang-Hong

    2014-03-01

    This paper provides a fast and patient-specific scatter artifact correction method for cone-beam computed tomography (CBCT) used in image-guided interventional procedures. Due to increased irradiated volume of interest in CBCT imaging, scatter radiation has increased dramatically compared to 2D imaging, leading to a degradation of image quality. In this study, we propose a scatter artifact correction strategy using an analytical convolution-based model whose free parameters are estimated using a rough estimation of scatter profiles from the acquired cone-beam projections. It was evaluated using Monte Carlo simulations with both monochromatic and polychromatic X-ray sources. The results demonstrated that the proposed method significantly reduced the scatter-induced shading artifacts and recovered CT numbers.

  19. Patient-specific dose estimation for pediatric chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Li Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P. [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Global Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 and Department of Radiology, Division of Pediatric Radiology, Duke University Medical Center, Durham North Carolina 27710 (United States)

    2008-12-15

    Current methods for organ and effective dose estimations in pediatric CT are largely patient generic. Physical phantoms and computer models have only been developed for standard/limited patient sizes at discrete ages (e.g., 0, 1, 5, 10, 15 years old) and do not reflect the variability of patient anatomy and body habitus within the same size/age group. In this investigation, full-body computer models of seven pediatric patients in the same size/protocol group (weight: 11.9-18.2 kg) were created based on the patients' actual multi-detector array CT (MDCT) data. Organs and structures in the scan coverage were individually segmented. Other organs and structures were created by morphing existing adult models (developed from visible human data) to match the framework defined by the segmented organs, referencing the organ volume and anthropometry data in ICRP Publication 89. Organ and effective dose of these patients from a chest MDCT scan protocol (64 slice LightSpeed VCT scanner, 120 kVp, 70 or 75 mA, 0.4 s gantry rotation period, pitch of 1.375, 20 mm beam collimation, and small body scan field-of-view) was calculated using a Monte Carlo program previously developed and validated to simulate radiation transport in the same CT system. The seven patients had normalized effective dose of 3.7-5.3 mSv/100 mAs (coefficient of variation: 10.8%). Normalized lung dose and heart dose were 10.4-12.6 mGy/100 mAs and 11.2-13.3 mGy/100 mAs, respectively. Organ dose variations across the patients were generally small for large organs in the scan coverage (<7%), but large for small organs in the scan coverage (9%-18%) and for partially or indirectly exposed organs (11%-77%). Normalized effective dose correlated weakly with body weight (correlation coefficient: r=-0.80). Normalized lung dose and heart dose correlated strongly with mid-chest equivalent diameter (lung: r=-0.99, heart: r=-0.93); these strong correlation relationships can be used to estimate patient-specific organ

  20. Using an EPID for patient-specific VMAT quality assurance

    International Nuclear Information System (INIS)

    Purpose: A patient-specific quality assurance (QA) method was developed to verify gantry-specific individual multileaf collimator (MLC) apertures (control points) in volumetric modulated arc therapy (VMAT) plans using an electronic portal imaging device (EPID). Methods: VMAT treatment plans were generated in an Eclipse treatment planning system (TPS). DICOM images from a Varian EPID (aS1000) acquired in continuous acquisition mode were used for pretreatment QA. Each cine image file contains the grayscale image of the MLC aperture related to its specific control point and the corresponding gantry angle information. The TPS MLC file of this RapidArc plan contains the leaf positions for all 177 control points (gantry angles). In-house software was developed that interpolates the measured images based on the gantry angle and overlays them with the MLC pattern for all control points. The 38% isointensity line was used to define the edge of the MLC leaves on the portal images. The software generates graphs and tables that provide analysis for the number of mismatched leaf positions for a chosen distance to agreement at each control point and the frequency in which each particular leaf mismatches for the entire arc. Results: Seven patients plans were analyzed using this method. The leaves with the highest mismatched rate were found to be treatment plan dependent. Conclusions: This in-house software can be used to automatically verify the MLC leaf positions for all control points of VMAT plans using cine images acquired by an EPID.

  1. Cosmetic Surgery

    Science.gov (United States)

    ... Body Looking and feeling your best Cosmetic surgery Cosmetic surgery Teens might have cosmetic surgery for a number ... about my body? What are the risks of cosmetic surgery? top People who have cosmetic surgery face many ...

  2. Nose Surgery

    Science.gov (United States)

    ... is as high a priority as appearance. Can Cosmetic Nasal Surgery Create A "Perfect" Nose? Aesthetic nasal surgery (rhinoplasty) ... Cover Nasal Surgery? Insurance usually does not cover cosmetic surgery. However, surgery to correct or improve breathing function, ...

  3. Cosmetic Surgery

    Science.gov (United States)

    ... Submit Home > Body Image > Cosmetic surgery Body Image Cosmetic surgery ASPS list of inappropriate candidates for surgery ... their appearance. Return to top Additional resources on cosmetic surgery Breast surgery Explore other publications and websites ...

  4. Patient-specific data fusion defines prognostic cancer subtypes.

    Directory of Open Access Journals (Sweden)

    Yinyin Yuan

    2011-10-01

    Full Text Available Different data types can offer complementary perspectives on the same biological phenomenon. In cancer studies, for example, data on copy number alterations indicate losses and amplifications of genomic regions in tumours, while transcriptomic data point to the impact of genomic and environmental events on the internal wiring of the cell. Fusing different data provides a more comprehensive model of the cancer cell than that offered by any single type. However, biological signals in different patients exhibit diverse degrees of concordance due to cancer heterogeneity and inherent noise in the measurements. This is a particularly important issue in cancer subtype discovery, where personalised strategies to guide therapy are of vital importance. We present a nonparametric Bayesian model for discovering prognostic cancer subtypes by integrating gene expression and copy number variation data. Our model is constructed from a hierarchy of Dirichlet Processes and addresses three key challenges in data fusion: (i To separate concordant from discordant signals, (ii to select informative features, (iii to estimate the number of disease subtypes. Concordance of signals is assessed individually for each patient, giving us an additional level of insight into the underlying disease structure. We exemplify the power of our model in prostate cancer and breast cancer and show that it outperforms competing methods. In the prostate cancer data, we identify an entirely new subtype with extremely poor survival outcome and show how other analyses fail to detect it. In the breast cancer data, we find subtypes with superior prognostic value by using the concordant results. These discoveries were crucially dependent on our model's ability to distinguish concordant and discordant signals within each patient sample, and would otherwise have been missed. We therefore demonstrate the importance of taking a patient-specific approach, using highly-flexible nonparametric

  5. Respiratory gated radiotherapy-pretreatment patient specific quality assurance.

    Science.gov (United States)

    Thiyagarajan, Rajesh; Sinha, Sujit Nath; Ravichandran, Ramamoorthy; Samuvel, Kothandaraman; Yadav, Girigesh; Sigamani, Ashok Kumar; Subramani, Vikraman; Raj, N Arunai Nambi

    2016-01-01

    Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D) phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT) is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany) in conjunction with "Real-time position management" (Varian, USA) to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT) film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA) phantom (Computerized Imaging Reference Systems type) is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%). Gamma value evaluated from EBT film shows passing rates 92-99% (96.63 ± 3.84%) for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level. PMID:27051173

  6. Respiratory gated radiotherapy-pretreatment patient specific quality assurance

    Directory of Open Access Journals (Sweden)

    Rajesh Thiyagarajan

    2016-01-01

    Full Text Available Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany in conjunction with "Real-time position management" (Varian, USA to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA phantom (Computerized Imaging Reference Systems type is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%. Gamma value evaluated from EBT film shows passing rates 92–99% (96.63 ± 3.84% for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level.

  7. Efficacy of an Intra-Operative Imaging Software System for Anatomic Anterior Cruciate Ligament Reconstruction Surgery

    Directory of Open Access Journals (Sweden)

    Xudong Zhang

    2012-01-01

    Full Text Available An imaging software system was studied for improving the performance of anatomic anterior cruciate ligament (ACL reconstruction which requires identifying ACL insertion sites for bone tunnel placement. This software predicts and displays the insertion sites based on the literature data and patient-specific bony landmarks. Twenty orthopaedic surgeons performed simulated arthroscopic ACL surgeries on 20 knee specimens, first without and then with the visual guidance by fluoroscopic imaging, and their tunnel entry positions were recorded. The native ACL insertion morphologies of individual specimens were quantified in relation to CT-based bone models and then used to evaluate the software-generated insertion locations. Results suggested that the system was effective in leading surgeons to predetermined locations while the application of averaged insertion morphological information in individual surgeries can be susceptible to inaccuracy and uncertainty. Implications on challenges associated with developing engineering solutions to aid in re-creating or recognizing anatomy in surgical care delivery are discussed.

  8. Generating patient-specific pulmonary vascular models for surgical planning

    Science.gov (United States)

    Murff, Daniel; Co-Vu, Jennifer; O'Dell, Walter G.

    2015-03-01

    Each year in the U.S., 7.4 million surgical procedures involving the major vessels are performed. Many of our patients require multiple surgeries, and many of the procedures include "surgical exploration". Procedures of this kind come with a significant amount of risk, carrying up to a 17.4% predicted mortality rate. This is especially concerning for our target population of pediatric patients with congenital abnormalities of the heart and major pulmonary vessels. This paper offers a novel approach to surgical planning which includes studying virtual and physical models of pulmonary vasculature of an individual patient before operation obtained from conventional 3D X-ray computed tomography (CT) scans of the chest. These models would provide clinicians with a non-invasive, intricately detailed representation of patient anatomy, and could reduce the need for invasive planning procedures such as exploratory surgery. Researchers involved in the AirPROM project have already demonstrated the utility of virtual and physical models in treatment planning of the airways of the chest. Clinicians have acknowledged the potential benefit from such a technology. A method for creating patient-derived physical models is demonstrated on pulmonary vasculature extracted from a CT scan with contrast of an adult human. Using a modified version of the NIH ImageJ program, a series of image processing functions are used to extract and mathematically reconstruct the vasculature tree structures of interest. An auto-generated STL file is sent to a 3D printer to create a physical model of the major pulmonary vasculature generated from 3D CT scans of patients.

  9. Generation of Human Lens Epithelial-Like Cells From Patient-Specific Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Li, Dan; Qiu, Xiaodi; Yang, Jin; Liu, Tianjin; Luo, Yi; Lu, Yi

    2016-12-01

    Cataractogenesis begins from the dynamic lens epithelial cells (LECs) and adjacent fiber cells. LECs derived from cell lines cannot maintain the crystalline expression as the primary LECs. The current study aimed to efficiently generate large numbers of human LECs from patient-specific induced pluripotent stem cells (iPSCs). Anterior lens capsules were collected from cataract surgery and were used to culture primary hLECs. iPSCs were induced from these primary hLECs by lentiviral transduction of Oct4, Sox2, Klf4, and c-Myc. Then, the generated iPSCs were re-differentiated into hLECs by the 3-step addition of defined factor combinations (Noggin, BMP4/7, bFGF, and EGF) modified from an established method. During the re-differentiation process, colonies of interest were isolated using a glass picking tool and cloning cylinders based on the colony morphology. After two steps of isolation, populations of LEC-like cells (LLCs) were generated and identified by the expression of lens marker genes by qPCR, western blot and immunofluorescence staining. The study introduced a modified protocol to isolate LLCs from iPSCs by defined factors in a short time frame. This technique could be useful for mechanistic studies of lens-related diseases. J. Cell. Physiol. 231: 2555-2562, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991066

  10. Patient-specific system for prognosis of surgical treatment outcomes of human cardiovascular system

    Science.gov (United States)

    Golyadkina, Anastasiya A.; Kalinin, Aleksey A.; Kirillova, Irina V.; Kossovich, Elena L.; Kossovich, Leonid Y.; Menishova, Liyana R.; Polienko, Asel V.

    2015-03-01

    Object of study: Improvement of life quality of patients with high stroke risk ia the main goal for development of system for patient-specific modeling of cardiovascular system. This work is dedicated at increase of safety outcomes for surgical treatment of brain blood supply alterations. The objects of study are common carotid artery, internal and external carotid arteries and bulb. Methods: We estimated mechanical properties of carotid arteries tissues and patching materials utilized at angioplasty. We studied angioarchitecture features of arteries. We developed and clinically adapted computer biomechanical models, which are characterized by geometrical, physical and mechanical similarity with carotid artery in norm and with pathology (atherosclerosis, pathological tortuosity, and their combination). Results: Collaboration of practicing cardiovascular surgeons and specialists in the area of Mathematics and Mechanics allowed to successfully conduct finite-element modeling of surgical treatment taking into account various features of operation techniques and patching materials for a specific patient. Numerical experiment allowed to reveal factors leading to brain blood supply decrease and atherosclerosis development. Modeling of carotid artery reconstruction surgery for a specific patient on the basis of the constructed biomechanical model demonstrated the possibility of its application in clinical practice at approximation of numerical experiment to the real conditions.

  11. Patient-Specific Simulations Reveal Significant Differences in Mechanical Stimuli in Venous and Arterial Coronary Grafts.

    Science.gov (United States)

    Ramachandra, Abhay B; Kahn, Andrew M; Marsden, Alison L

    2016-08-01

    Mechanical stimuli are key to understanding disease progression and clinically observed differences in failure rates between arterial and venous grafts following coronary artery bypass graft surgery. We quantify biologically relevant mechanical stimuli, not available from standard imaging, in patient-specific simulations incorporating non-invasive clinical data. We couple CFD with closed-loop circulatory physiology models to quantify biologically relevant indices, including wall shear, oscillatory shear, and wall strain. We account for vessel-specific material properties in simulating vessel wall deformation. Wall shear was significantly lower (p = 0.014*) and atheroprone area significantly higher (p = 0.040*) in venous compared to arterial grafts. Wall strain in venous grafts was significantly lower (p = 0.003*) than in arterial grafts while no significant difference was observed in oscillatory shear index. Simulations demonstrate significant differences in mechanical stimuli acting on venous vs. arterial grafts, in line with clinically observed graft failure rates, offering a promising avenue for stratifying patients at risk for graft failure. PMID:27447176

  12. The Effect of Femoral Cutting Guide Design Improvements for Patient-Specific Instruments

    Directory of Open Access Journals (Sweden)

    Oh-Ryong Kwon

    2015-01-01

    Full Text Available Although the application of patient-specific instruments (PSI for total knee arthroplasty (TKA increases the cost of the surgical procedure, PSI may reduce operative time and improve implant alignment, which could reduce the number of revision surgeries. We report our experience with TKA using PSI techniques in 120 patients from March to December 2014. PSI for TKA were created from data provided by computed tomography (CT scans or magnetic resonance imaging (MRI; which imaging technology is more reliable for the PSI technique remains unclear. In the first 20 patients, the accuracy of bone resection and PSI stability were compared between CT and MRI scans with presurgical results as a reference; MRI produced better results. In the second and third groups, each with 50 patients, the results of bone resection and stability were compared in MRI scans with respect to the quality of scanning due to motion artifacts and experienced know-how in PSI design, respectively. The optimized femoral cutting guide design for PSI showed the closest outcomes in bone resection and PSI stability with presurgical data. It is expected that this design could be a reasonable guideline in PSI.

  13. Patient-Specific Variations in Biomarkers across Gingivitis and Periodontitis.

    Science.gov (United States)

    Nagarajan, Radhakrishnan; Miller, Craig S; Dawson, Dolph; Al-Sabbagh, Mohanad; Ebersole, Jeffrey L

    2015-01-01

    This study investigates the use of saliva, as an emerging diagnostic fluid in conjunction with classification techniques to discern biological heterogeneity in clinically labelled gingivitis and periodontitis subjects (80 subjects; 40/group) A battery of classification techniques were investigated as traditional single classifier systems as well as within a novel selective voting ensemble classification approach (SVA) framework. Unlike traditional single classifiers, SVA is shown to reveal patient-specific variations within disease groups, which may be important for identifying proclivity to disease progression or disease stability. Salivary expression profiles of IL-1ß, IL-6, MMP-8, and MIP-1α from 80 patients were analyzed using four classification algorithms (LDA: Linear Discriminant Analysis [LDA], Quadratic Discriminant Analysis [QDA], Naïve Bayes Classifier [NBC] and Support Vector Machines [SVM]) as traditional single classifiers and within the SVA framework (SVA-LDA, SVA-QDA, SVA-NB and SVA-SVM). Our findings demonstrate that performance measures (sensitivity, specificity and accuracy) of traditional classification as single classifier were comparable to that of the SVA counterparts using clinical labels of the samples as ground truth. However, unlike traditional single classifier approaches, the normalized ensemble vote-counts from SVA revealed varying proclivity of the subjects for each of the disease groups. More importantly, the SVA identified a subset of gingivitis and periodontitis samples that demonstrated a biological proclivity commensurate with the other clinical group. This subset was confirmed across SVA-LDA, SVA-QDA, SVA-NB and SVA-SVM. Heatmap visualization of their ensemble sets revealed lack of consensus between these subsets and the rest of the samples within the respective disease groups indicating the unique nature of the patients in these subsets. While the source of variation is not known, the results presented clearly elucidate the

  14. Adaptive grid generation in a patient-specific cerebral aneurysm

    Science.gov (United States)

    Hodis, Simona; Kallmes, David F.; Dragomir-Daescu, Dan

    2013-11-01

    computational time for patient-specific hemodynamics simulations, which are used to help assess the likelihood of aneurysm rupture using CFD calculated flow patterns.

  15. Patient-Specific Variations in Biomarkers across Gingivitis and Periodontitis.

    Directory of Open Access Journals (Sweden)

    Radhakrishnan Nagarajan

    Full Text Available This study investigates the use of saliva, as an emerging diagnostic fluid in conjunction with classification techniques to discern biological heterogeneity in clinically labelled gingivitis and periodontitis subjects (80 subjects; 40/group A battery of classification techniques were investigated as traditional single classifier systems as well as within a novel selective voting ensemble classification approach (SVA framework. Unlike traditional single classifiers, SVA is shown to reveal patient-specific variations within disease groups, which may be important for identifying proclivity to disease progression or disease stability. Salivary expression profiles of IL-1ß, IL-6, MMP-8, and MIP-1α from 80 patients were analyzed using four classification algorithms (LDA: Linear Discriminant Analysis [LDA], Quadratic Discriminant Analysis [QDA], Naïve Bayes Classifier [NBC] and Support Vector Machines [SVM] as traditional single classifiers and within the SVA framework (SVA-LDA, SVA-QDA, SVA-NB and SVA-SVM. Our findings demonstrate that performance measures (sensitivity, specificity and accuracy of traditional classification as single classifier were comparable to that of the SVA counterparts using clinical labels of the samples as ground truth. However, unlike traditional single classifier approaches, the normalized ensemble vote-counts from SVA revealed varying proclivity of the subjects for each of the disease groups. More importantly, the SVA identified a subset of gingivitis and periodontitis samples that demonstrated a biological proclivity commensurate with the other clinical group. This subset was confirmed across SVA-LDA, SVA-QDA, SVA-NB and SVA-SVM. Heatmap visualization of their ensemble sets revealed lack of consensus between these subsets and the rest of the samples within the respective disease groups indicating the unique nature of the patients in these subsets. While the source of variation is not known, the results presented clearly

  16. Patient-Specific CT-Based Instrumentation versus Conventional Instrumentation in Total Knee Arthroplasty: A Prospective Randomized Controlled Study on Clinical Outcomes and In-Hospital Data

    Directory of Open Access Journals (Sweden)

    Andrzej Kotela

    2015-01-01

    Full Text Available Total knee arthroplasty (TKA is a frequently performed procedure in orthopaedic surgery. Recently, patient-specific instrumentation was introduced to facilitate correct positioning of implants. The aim of this study was to compare the early clinical results of TKA performed with patient-specific CT-based instrumentation and conventional technique. A prospective, randomized controlled trial on 112 patients was performed between January 2011 and December 2011. A group of 112 patients who met the inclusion and exclusion criteria were enrolled in this study and randomly assigned to an experimental or control group. The experimental group comprised 52 patients who received the Signature CT-based implant positioning system, and the control group consisted of 60 patients with conventional instrumentation. Clinical outcomes were evaluated with the KSS scale, WOMAC scale, and VAS scales to assess knee pain severity and patient satisfaction with the surgery. Specified in-hospital data were recorded. Patients were followed up for 12 months. At one year after surgery, there were no statistically significant differences between groups with respect to clinical outcomes and in-hospital data, including operative time, blood loss, hospital length of stay, intraoperative observations, and postoperative complications. Further high-quality investigations of various patient-specific systems and longer follow-up may be helpful in assessing their utility for TKA.

  17. Patterns of patient specific dosimetry in total body irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Akino, Yuichi [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States); Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871 (Japan); McMullen, Kevin P.; Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States)

    2013-04-15

    Purpose: Total body irradiation (TBI) has been used for bone marrow transplant for hematologic and immune deficiency conditions. The goal of TBI is to deliver a homogeneous dose to the entire body, with a generally accepted range of dose uniformity being within {+-}10% of the prescribed dose. The moving table technique for TBI could make dose uniform in whole body by adjusting couch speed. However, it is difficult to accurately estimate the actual dose by calculation and hence in vivo dosimetry (IVD) is routinely performed. Here, the authors present patterns of patient-specific IVD in 161 TBI patients treated at our institution. Methods: Cobalt-60 teletherapy unit (Model C9 Cobalt-60 teletherapy unit, Picker X-ray Corporation) with customized moving bed (SITI Industrial Products, Inc., Fishers, IN) were used for TBI treatment. During treatment, OneDose{sup TM} (Sicel Technology, NC) Metal Oxide-silicon Semiconductor Field Effect Transistor detectors were placed at patient body surface; both entrance and exit side of the beam at patient head, neck, mediastinum, umbilicus, and knee to estimate midplane dose. When large differences (>10%) between the prescribed and measured dose were observed, dose delivery was corrected for subsequent fractions by the adjustment of couch speed and/or bolus placement. Under IRB exempt status, the authors retrospectively analyzed the treatment records of 161 patients who received TBI treatment between 2006 and 2011. Results: Across the entire cohort, the median {+-} SD (range) percent variance between calculated and measured dose for head, neck, mediastinum, umbilicus, and knee was -2.3 {+-} 10.2% (-66.2 to +35.3), 1.1 {+-} 11.5% (-62.2 to +40.3), -1.9 {+-} 9.5% (-66.4 to +46.6), -1.1 {+-} 7.2% (-35.2 to +42.9), and 3.4 {+-} 12.2% (-47.9 to +108.5), respectively. More than half of treatments were within {+-}10% of the prescribed dose for all anatomical regions. For 80% of treatments (10%-90%), dose at the umbilicus was within {+-}10

  18. Emerging Applications of Bedside 3D Printing in Plastic Surgery.

    Science.gov (United States)

    Chae, Michael P; Rozen, Warren M; McMenamin, Paul G; Findlay, Michael W; Spychal, Robert T; Hunter-Smith, David J

    2015-01-01

    Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing

  19. Emerging Applications of Bedside 3D Printing in Plastic Surgery

    Directory of Open Access Journals (Sweden)

    Michael P Chae

    2015-06-01

    Full Text Available Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D reconstructions, are limited by their representation on 2D workstations. 3D printing has been embraced by early adopters to produce medical imaging-guided 3D printed biomodels that facilitate various aspects of clinical practice. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. With increasing accessibility, investigators are now able to convert standard imaging data into Computer Aided Design (CAD files using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography (SLA, multijet modeling (MJM, selective laser sintering (SLS, binder jet technique (BJT, and fused deposition modeling (FDM. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without out-sourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. In this review the existing uses of 3D printing in plastic surgery practice, spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative aesthetics, are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, patient and surgical trainee education, and the development of intraoperative guidance tools and patient-specific prosthetics in everyday surgical practice.

  20. Cataract Surgery

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ...

  1. [Application of a CO2 laser for oral soft tissue surgery in children in Sri Lanka--introduction of a laser through activities of aid to a developing country].

    Science.gov (United States)

    Kato, Junji; Jayawardena, Jayanetti Asiri; Wijeyeweera, Rafel Luxhmen; Moriya, Kayoko; Takagi, Yuzo

    2002-03-01

    The objective of this study was to clarify the effect of CO2 laser irradiation on oral tissue problems in children in Sri Lanka, through the activities of aid to a developing country by the Japan International Cooperation Agency. This study took about six months, during two times periods: from November 2000 to February 2001, and from July 2001 to October 2001, in the paedodontic clinic of the Faculty of Dental Science, University of Peradeniya, in Sri Lanka. A CO2 laser was used on 48 subjects (51 cases), aged between 1 and 15 years, having main indications for labial frenectomy, frenectomy in ankyloglossia, and excision of mucocele. The results indicated that the CO2 laser had the following advantages. 1. Soft tissue cutting was efficient, with no bleeding, giving a clear operative field during operation. 2. There was no need to use sutures. 3. The surgery itself was simple and less time-consuming. Hence, there was no need for general anesthesia for such cases as tongue tie operation in small children. 4. There was no postsurgical infection. As a result, there was no need for analgesics or antibiotics, as post-surgical pain and infection were prevented. 5. Wound contraction and scarring were decreased or eliminated. Considering the above advantages, the use of a CO2 laser proved to be very safe and effective for soft tissue surgery, especially for children in developing countries such as Sri Lanka. PMID:11968836

  2. Circuito Quirúrgico Informatizado: Una herramienta para la mejora de la atención al paciente quirúrgico Improving the Care level on a surgery-needed patient through a Computer-Aided Surgery Cares Program

    Directory of Open Access Journals (Sweden)

    Luis Fuentes Cebada

    2007-11-01

    Full Text Available El Programa de Atención al Paciente Quirúrgico en el Hospital Puerta del Mar (Cádiz surge con el objetivo de personalizar la atención y garantizar la continuidad de cuidados y la seguridad de nuestros pacientes en cada una de las unidades por las que va desarrollándose la actividad quirúrgica. Este programa se soporta en una herramienta informática que es el circuito quirúrgico, la cual ha sido diseñada siguiendo la metodología de mejora continua y la participación desde el inicio de los profesionales enfermeros como actores de su desarrollo e implantación. En sólo ocho meses se ha conseguido que más del 55 % de los pacientes intervenidos quirúrgicamente disponga de un registro informatizado en el que se valoran, diagnostican, planifican y abordan los aspectos relacionados con la propia intervención quirúrgica como una parte añadida a las respuestas humanas que la misma ocasiona tanto a él como a su familia. Todo ello haciendo uso de las taxonomías enfermeras NANDA, NOC y NIC, con un enfoque holístico, centrado en la persona como agente y receptor de cuidados. Acompaña a este registro un sistema de información desde el que se explotan aspectos tales como la prevalencia diagnóstica enfermera, intervenciones realizadas, alergias, profilaxis antibiótica administrada, etc.The Surgery-needed Care Program, currently under test at the Puerta del Mar Hospital in Cadiz, has been conceived with the aim of both tuning the care level to each individual patient and, at the same time, to secure a continuous assistance through all the units involved in the surgery process. It is based on a computer tool so called Surgery Program. This computer application has been designed on the basis of continually-improving approach while counting with the enrolment, from the very first phases, of nurses in the affected units both in development and set-up steps. After just eight months running this Program, we have been able to create a digital

  3. Imaging aid for thoracic surgery. Multidetector-row computed tomography evaluation of the tracheobronchial structure and bronchial tube selection for one-lung anesthesia

    International Nuclear Information System (INIS)

    The tracheobronchial structures were evaluated by multidetector-row computed tomography (MDCT), which provided imaging information for one-lung anesthesia during thoracic surgery. The subjects consisted of 100 patients. Three-dimensional (3D) images of the tracheobronchial structures and the bronchial tubes were created. Individual differences were found in the tracheobronchial structures in 100 patients. The length and the diameter of the right main bronchus were measured with 3D images and were not related to the patient's physical appearance, such as body height. Problematic intubation cases included a short right main bronchus <10 mm, an anomaly of the right bronchus, and tracheal stenosis. The 3D images demonstrated problematic areas of the tracheobronchial structure and helped the anesthesiologists select the most appropriate bronchial tube suitable for the tracheobronchial structure variations. Therefore, this technique is considered to contribute to safer performance of one-lung anesthesia. (author)

  4. The Effect of Patient-Specific Cerebral Oxygenation Monitoring on Postoperative Cognitive Function: A Multicenter Randomized Controlled Trial

    Science.gov (United States)

    Ellis, Lucy; Murphy, Gavin J; Culliford, Lucy; Dreyer, Lucy; Clayton, Gemma; Downes, Richard; Nicholson, Eamonn; Stoica, Serban; Reeves, Barnaby C

    2015-01-01

    Background Indices of global tissue oxygen delivery and utilization such as mixed venous oxygen saturation, serum lactate concentration, and arterial hematocrit are commonly used to determine the adequacy of tissue oxygenation during cardiopulmonary bypass (CPB). However, these global measures may not accurately reflect regional tissue oxygenation and ischemic organ injury remains a common and serious complication of CPB. Near-infrared spectroscopy (NIRS) is a noninvasive technology that measures regional tissue oxygenation. NIRS may be used alongside global measures to optimize regional perfusion and reduce organ injury. It may also be used as an indicator of the need for red blood cell transfusion in the presence of anemia and tissue hypoxia. However, the clinical benefits of using NIRS remain unclear and there is a lack of high-quality evidence demonstrating its efficacy and cost effectiveness. Objective The aim of the patient-specific cerebral oxygenation monitoring as part of an algorithm to reduce transfusion during heart valve surgery (PASPORT) trial is to determine whether the addition of NIRS to CPB management algorithms can prevent cognitive decline, postoperative organ injury, unnecessary transfusion, and reduce health care costs. Methods Adults aged 16 years or older undergoing valve or combined coronary artery bypass graft and valve surgery at one of three UK cardiac centers (Bristol, Hull, or Leicester) are randomly allocated in a 1:1 ratio to either a standard algorithm for optimizing tissue oxygenation during CPB that includes a fixed transfusion threshold, or a patient-specific algorithm that incorporates cerebral NIRS monitoring and a restrictive red blood cell transfusion threshold. Allocation concealment, Internet-based randomization stratified by operation type and recruiting center, and blinding of patients, ICU and ward care staff, and outcome assessors reduce the risk of bias. The primary outcomes are cognitive function 3 months after

  5. Methodologies for Development of Patient Specific Bone Models from Human Body CT Scans

    Science.gov (United States)

    Chougule, Vikas Narayan; Mulay, Arati Vinayak; Ahuja, Bharatkumar Bhagatraj

    2016-06-01

    This work deals with development of algorithm for physical replication of patient specific human bone and construction of corresponding implants/inserts RP models by using Reverse Engineering approach from non-invasive medical images for surgical purpose. In medical field, the volumetric data i.e. voxel and triangular facet based models are primarily used for bio-modelling and visualization, which requires huge memory space. On the other side, recent advances in Computer Aided Design (CAD) technology provides additional facilities/functions for design, prototyping and manufacturing of any object having freeform surfaces based on boundary representation techniques. This work presents a process to physical replication of 3D rapid prototyping (RP) physical models of human bone from various CAD modeling techniques developed by using 3D point cloud data which is obtained from non-invasive CT/MRI scans in DICOM 3.0 format. This point cloud data is used for construction of 3D CAD model by fitting B-spline curves through these points and then fitting surface between these curve networks by using swept blend techniques. This process also can be achieved by generating the triangular mesh directly from 3D point cloud data without developing any surface model using any commercial CAD software. The generated STL file from 3D point cloud data is used as a basic input for RP process. The Delaunay tetrahedralization approach is used to process the 3D point cloud data to obtain STL file. CT scan data of Metacarpus (human bone) is used as the case study for the generation of the 3D RP model. A 3D physical model of the human bone is generated on rapid prototyping machine and its virtual reality model is presented for visualization. The generated CAD model by different techniques is compared for the accuracy and reliability. The results of this research work are assessed for clinical reliability in replication of human bone in medical field.

  6. [Computer-aided reconstruction of the facial skeleton : Planning and implementation in clinical routine].

    Science.gov (United States)

    Wilde, F; Schramm, A

    2016-09-01

    In computer-aided reconstruction of the facial skeleton, a workflow has been established involving the following steps: > diagnosis → planning and simulation → surgical procedure → validation and quality control virtual model of the desired surgical outcome using special planning software. The accuracy of implant fit can be virtually verified before surgery. 3D models and virtual reconstructions can be used for manufacturing patient-specific implants. During the surgical procedure, planning must be transferred to the surgical site as accurately as possible. A number of techniques are available for this purpose, e. g., closed reduction, open reduction with the placement of anatomically preformed or patient-specific implants in combination with surgical guides, and the additional use of navigation. Validation and quality control require postprocedural 3D imaging. After reconstructions of the midface, 3D imaging should be performed even before surgery is completed. Malpositions can thus be directly corrected and unnecessary open reconstructions avoided. Mobile 3D c-arms are particularly useful for intraoperative 3D imaging. Whereas intraoperative imaging makes postoperative imaging after midface reconstruction unnecessary in many cases, postoperative 3D imaging in addition to intraoperative imaging may still be recommended after complex reconstructions of the facial skeleton. PMID:27525666

  7. Three-Dimensional Planning in Maxillofacial Fracture Surgery: Computer-Aided Design/Computer-Aided Manufacture Surgical Splints by Integrating Cone Beam Computerized Tomography Images Into Multislice Computerized Tomography Images.

    Science.gov (United States)

    Ren, Jiayin; Zhou, Zhongwei; Li, Peng; Tang, Wei; Guo, Jixiang; Wang, Hu; Tian, Weidong

    2016-09-01

    This study aimed to evaluate an innovative workflow for maxillofacial fracture surgery planning and surgical splint designing. The maxillofacial multislice computerized tomography (MSCT) data and dental cone beam computerized tomography (CBCT) data both were obtained from 40 normal adults and 58 adults who suffered fractures. The each part of the CBCT dentition image was registered into MSCT image by the use of the iterative closest point algorithm. Volume evaluation of the virtual splints that were designed by the registered MSCT images and MSCT images of the same object was performed. Eighteen patients (group 1) were operated without any splint. Twenty-one (group 2) and 19 patients (group 3) used the splints designed according to the MSCT images and registered MSCT images, respectively. The authors' results showed that the mean errors between the 2 models ranged from 0.53 to 0.92 mm and the RMS errors ranged from 0.38 to 0.69 mm in fracture patients. The mean errors between the 2 models ranged from 0.47 to 0.85 mm and the RMS errors ranged from 0.33 to 0.71 mm in normal adults. 72.22% patients in group 1 recovered occlusion. 85.71% patients in group 2, and 94.73% patients in group 3 reconstructed occlusion. There was a statistically significant difference between the MSCT images based splints' volume and the registered MSCT splints' volume in patients (P images based splints' volume was statistically significantly distinct from the registered MSCT splints' volume in normal adults (P images based splints' volume and the registered MSCT splints' volume in patients and normal adults (P CBCT images into MSCT images for splints designing was feasible. The volume of the splints designed by MSCT images tended to be smaller than the splints designed by the integrated MSCT images. The patients operated with splints tended to regain occlusion. The patients who were operated with the splints which were designed according to registered MSCT images tended to get

  8. Combining Population and Patient-Specific Characteristics for Prostate Segmentation on 3D CT Images

    Science.gov (United States)

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-01-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy.

  9. Plastic Surgery

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A ... her forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word " ...

  10. Foot Surgery

    Science.gov (United States)

    ... in the toe to maintain realignment. Neuroma Surgery: Neuroma surgery involves removing a benign enlargement of a nerve, usually between the metatarsal heads in the ball of the foot. This soft tissue surgery tends to have a ...

  11. Lung surgery

    Science.gov (United States)

    ... Pneumonectomy; Lobectomy; Lung biopsy; Thoracoscopy; Video-assisted thoracoscopic surgery; VATS ... You will have general anesthesia before surgery. You will be asleep and unable to feel pain. Two common ways to do surgery on your lungs are thoracotomy and video- ...

  12. 微信辅助教学法在外科手术学基础课程中的应用%Application of Wechat-aided teaching in foundation courses of surgery science

    Institute of Scientific and Technical Information of China (English)

    单成祥; 裘年存; 仇明; 徐志飞; 沈宏亮

    2014-01-01

    Wechat, popular instant messaging software in smartphones, has a lot of functions and features, making it have the potential of being widely used in practice-oriented medical course teaching. Our hospital has carried out the practice of Wechat-aided teaching in foundation courses of surgery.It breaks the shackles of the traditional classroom in space and time, mobilizes students'enthusiasm for learning, improves their ability to practice operations, and enhances their communication skills and sense of teamwork, thus achieving better teaching results.%微信是智能手机中一款非常普及的即时通讯软件,它本身具备的很多功能和特性在实践类医学课程教学中有较大的潜在应用价值。第二军医大学附属长征医院在外科手术基础教学中应用微信辅助教学,突破了传统课堂教学空间和时间的束缚,调动了学生自主学习的积极性,提高了学生实践操作的能力,增强了学生沟通能力及团队协作意识,取得了较好的教学效果。

  13. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    OpenAIRE

    Ionita, Ciprian N.; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R.; Xiang, Jianping; Snyder, Kenneth V.; Siddiqui, Adnan H; Levy, Elad I; Meng, Hui; Rudin, Stephen

    2014-01-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital s...

  14. Computer simulation in the daily practice of orthognathic surgery.

    Science.gov (United States)

    Schendel, S A

    2015-12-01

    The availability of computers and advances in imaging, especially over the last 10 years, have allowed the adoption of three-dimensional (3D) imaging in the office setting. The affordability and ease of use of this modality has led to its widespread implementation in diagnosis and treatment planning, teaching, and follow-up care. 3D imaging is particularly useful when the deformities are complex and involve both function and aesthetics, such as those in the dentofacial area, and for orthognathic surgery. Computer imaging involves combining images obtained from different modalities to create a virtual record of an individual. In this article, the system is described and its use in the office demonstrated. Computer imaging with simulation, and more specifically patient-specific anatomic records (PSAR), permit a more accurate analysis of the deformity as an aid to diagnosis and treatment planning. 3D imaging and computer simulation can be used effectively for the planning of office-based procedures. The technique can be used to perform virtual surgery and establish a definitive and objective treatment plan for correction of the facial deformity. In addition, patient education and follow-up can be facilitated. The end result is improved patient care and decreased expense.

  15. Foreign aid

    DEFF Research Database (Denmark)

    Tarp, Finn

    2008-01-01

    Foreign aid has evolved significantly since the Second World War in response to a dramatically changing global political and economic context. This article (a) reviews this process and associated trends in the volume and distribution of foreign aid; (b) reviews the goals, principles...... and institutions of the aid system; and (c) discusses whether aid has been effective. While much of the original optimism about the impact of foreign aid needed modification, there is solid evidence that aid has indeed helped further growth and poverty reduction...

  16. Aid Effectiveness

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    Controversy over the aggregate impact of foreign aid has focused on reduced form estimates of the aid-growth link. The causal chain, through which aid affects developmental outcomes including growth, has received much less attention. We address this gap by: (i) specifying a structural model...... of the main relationships; (ii) estimating the impact of aid on a range of final and intermediate outcomes; and (iii) quantifying a simplied representation of the full structural form, where aid impacts on growth through key intermediate outcomes. A coherent picture emerges: aid stimulates growth and reduces...

  17. Advancing drug discovery for neuropsychiatric disorders using patient-specific stem cell models.

    Science.gov (United States)

    Haggarty, Stephen J; Silva, M Catarina; Cross, Alan; Brandon, Nicholas J; Perlis, Roy H

    2016-06-01

    Compelling clinical, social, and economic reasons exist to innovate in the process of drug discovery for neuropsychiatric disorders. The use of patient-specific, induced pluripotent stem cells (iPSCs) now affords the ability to generate neuronal cell-based models that recapitulate key aspects of human disease. In the context of neuropsychiatric disorders, where access to physiologically active and relevant cell types of the central nervous system for research is extremely limiting, iPSC-derived in vitro culture of human neurons and glial cells is transformative. Potential applications relevant to early stage drug discovery, include support of quantitative biochemistry, functional genomics, proteomics, and perhaps most notably, high-throughput and high-content chemical screening. While many phenotypes in human iPSC-derived culture systems may prove adaptable to screening formats, addressing the question of which in vitro phenotypes are ultimately relevant to disease pathophysiology and therefore more likely to yield effective pharmacological agents that are disease-modifying treatments requires careful consideration. Here, we review recent examples of studies of neuropsychiatric disorders using human stem cell models where cellular phenotypes linked to disease and functional assays have been reported. We also highlight technical advances using genome-editing technologies in iPSCs to support drug discovery efforts, including the interpretation of the functional significance of rare genetic variants of unknown significance and for the purpose of creating cell type- and pathway-selective functional reporter assays. Additionally, we evaluate the potential of in vitro stem cell models to investigate early events of disease pathogenesis, in an effort to understand the underlying molecular mechanism, including the basis of selective cell-type vulnerability, and the potential to create new cell-based diagnostics to aid in the classification of patients and subsequent

  18. AIDS (image)

    Science.gov (United States)

    AIDS (acquired immune deficiency syndrome) is caused by HIV (human immunodeficiency virus), and is a syndrome that ... life-threatening illnesses. There is no cure for AIDS, but treatment with antiviral medication can suppress symptoms. ...

  19. Hearing Aids

    Science.gov (United States)

    ... more in both quiet and noisy situations. Hearing aids help people who have hearing loss from damage ... your doctor. There are different kinds of hearing aids. They differ by size, their placement on or ...

  20. Long-Term Morphological and Microarchitectural Stability of Tissue-Engineered, Patient-Specific Auricles In Vivo.

    Science.gov (United States)

    Cohen, Benjamin Peter; Hooper, Rachel C; Puetzer, Jennifer L; Nordberg, Rachel; Asanbe, Ope; Hernandez, Karina A; Spector, Jason A; Bonassar, Lawrence J

    2016-03-01

    Current techniques for autologous auricular reconstruction produce substandard ear morphologies with high levels of donor-site morbidity, whereas alloplastic implants demonstrate poor biocompatibility. Tissue engineering, in combination with noninvasive digital photogrammetry and computer-assisted design/computer-aided manufacturing technology, offers an alternative method of auricular reconstruction. Using this method, patient-specific ears composed of collagen scaffolds and auricular chondrocytes have generated auricular cartilage with great fidelity following 3 months of subcutaneous implantation, however, this short time frame may not portend long-term tissue stability. We hypothesized that constructs developed using this technique would undergo continued auricular cartilage maturation without degradation during long-term (6 month) implantation. Full-sized, juvenile human ear constructs were injection molded from high-density collagen hydrogels encapsulating juvenile bovine auricular chondrocytes and implanted subcutaneously on the backs of nude rats for 6 months. Upon explantation, constructs retained overall patient morphology and displayed no evidence of tissue necrosis. Limited contraction occurred in vivo, however, no significant change in size was observed beyond 1 month. Constructs at 6 months showed distinct auricular cartilage microstructure, featuring a self-assembled perichondrial layer, a proteoglycan-rich bulk, and rounded cellular lacunae. Verhoeff's staining also revealed a developing elastin network comparable to native tissue. Biochemical measurements for DNA, glycosaminoglycan, and hydroxyproline content and mechanical properties of aggregate modulus and hydraulic permeability showed engineered tissue to be similar to native cartilage at 6 months. Patient-specific auricular constructs demonstrated long-term stability and increased cartilage tissue development during extended implantation, and offer a potential tissue-engineered solution for

  1. SU-E-T-04: 3D Printed Patient-Specific Surface Mould Applicators for Brachytherapy Treatment of Superficial Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Cumming, I; Lasso, A; Rankin, A; Fichtinger, G [Laboratory for Percutaneous Surgery, School of Computing, Queen' s University, Kingston, Ontario (Canada); Joshi, C P; Falkson, C; Schreiner, L John [CCSEO, Kingston General Hospital and Department of Oncology, Queen' s University, Kingston, Ontario (Canada)

    2014-06-01

    Purpose: Evaluate the feasibility of constructing 3D-printed patient-specific surface mould applicators for HDR brachytherapy treatment of superficial lesions. Methods: We propose using computer-aided design software to create 3D printed surface mould applicators for brachytherapy. A mould generation module was developed in the open-source 3D Slicer ( http://www.slicer.org ) medical image analysis platform. The system extracts the skin surface from CT images, and generates smooth catheter paths over the region of interest based on user-defined start and end points at a specified stand-off distance from the skin surface. The catheter paths are radially extended to create catheter channels that are sufficiently wide to ensure smooth insertion of catheters for a safe source travel. An outer mould surface is generated to encompass the channels. The mould is also equipped with fiducial markers to ensure its reproducible placement. A surface mould applicator with eight parallel catheter channels of 4mm diameters was fabricated for the nose region of a head phantom; flexible plastic catheters of 2mm diameter were threaded through these channels maintaining 10mm catheter separations and a 5mm stand-off distance from the skin surface. The apparatus yielded 3mm thickness of mould material between channels and the skin. The mould design was exported as a stereolithography file to a Dimension SST1200es 3D printer and printed using ABS Plus plastic material. Results: The applicator closely matched its design and was found to be sufficiently rigid without deformation during repeated application on the head phantom. Catheters were easily threaded into channels carved along catheter paths. Further tests are required to evaluate feasibility of channel diameters smaller than 4mm. Conclusion: Construction of 3D-printed mould applicators show promise for use in patient specific brachytherapy of superficial lesions. Further evaluation of 3D printing techniques and materials is required

  2. SU-E-T-04: 3D Printed Patient-Specific Surface Mould Applicators for Brachytherapy Treatment of Superficial Lesions

    International Nuclear Information System (INIS)

    Purpose: Evaluate the feasibility of constructing 3D-printed patient-specific surface mould applicators for HDR brachytherapy treatment of superficial lesions. Methods: We propose using computer-aided design software to create 3D printed surface mould applicators for brachytherapy. A mould generation module was developed in the open-source 3D Slicer ( http://www.slicer.org ) medical image analysis platform. The system extracts the skin surface from CT images, and generates smooth catheter paths over the region of interest based on user-defined start and end points at a specified stand-off distance from the skin surface. The catheter paths are radially extended to create catheter channels that are sufficiently wide to ensure smooth insertion of catheters for a safe source travel. An outer mould surface is generated to encompass the channels. The mould is also equipped with fiducial markers to ensure its reproducible placement. A surface mould applicator with eight parallel catheter channels of 4mm diameters was fabricated for the nose region of a head phantom; flexible plastic catheters of 2mm diameter were threaded through these channels maintaining 10mm catheter separations and a 5mm stand-off distance from the skin surface. The apparatus yielded 3mm thickness of mould material between channels and the skin. The mould design was exported as a stereolithography file to a Dimension SST1200es 3D printer and printed using ABS Plus plastic material. Results: The applicator closely matched its design and was found to be sufficiently rigid without deformation during repeated application on the head phantom. Catheters were easily threaded into channels carved along catheter paths. Further tests are required to evaluate feasibility of channel diameters smaller than 4mm. Conclusion: Construction of 3D-printed mould applicators show promise for use in patient specific brachytherapy of superficial lesions. Further evaluation of 3D printing techniques and materials is required

  3. 导航技术在颅底-颞下区肿瘤手术中的应用%Application of computer-aided design and navigation technology in skull base and infratemporal fossa tumor surgery

    Institute of Scientific and Technical Information of China (English)

    郭玉兴; 彭歆; 刘筱菁; 张雷; 俞光岩; 郭传殡

    2013-01-01

    Objective To evaluate the application of computer-aided design and navigation technology in skull base and infratemporal fossa tumor surgery and to analyze its advantages and disadvantages.Methods Twenty-nine cases with tumor of skull base and infratemporal fossa were treated with computer-aided design and navigation surgery.The Parameters of age,gender,primary or recurrent tumor,tumor nature and surgical approach were recorded.Results En bloc resection was performed in 20 cases and subtotal resection in 9 cases.The margin status was negative margin in 8 cases,near-tumor margin in 17 cases and positive resection margin in 4 cases.Postoperative complication rate was 14% (4/29).During the follow-up period,2 benign cases recurred.In the malignant group,there were 7 cases of recurrence,2 cases of metastasis and 3 deaths.The 5-year overall survival and progression-free survival rate were 69% and 40% respectively.Conclusions Navigation technology can enhance the confidence of the surgeons and operation safety in handling malignant tumors in skull base and infratemporal fossa.%目的 评价计算机辅助设计导航技术在颅底-颞下区肿瘤手术中的应用价值.方法 对29例颅底-颞下区肿瘤患者行计算机辅助手术方案设计及术中导航.记录患者的年龄、性别、肿瘤原发或复发、肿瘤性质及手术入路.应用SPSS 13.0软件计算生存率.结果 肿瘤完全切除20例、近全切除7例、次全切除2例;切除方式:整块切除20例、分块切除9例;切缘状态:阴性切缘8例、近肿瘤切除17例、阳性切缘4例.术后并发症发生率为14%(4/29).随访期内良性肿瘤复发2例.恶性肿瘤复发7例、转移2例、死亡3例,恶性肿瘤5年总生存率和无进展生存率分别为69%和40%.结论 计算机辅助设计导航技术可提高颅底-颞下区外科操作的手术安全性.

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

    Science.gov (United States)

    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

  5. Effects of Vessel Tortuosity on Coronary Hemodynamics: An Idealized and Patient-Specific Computational Study.

    Science.gov (United States)

    Vorobtsova, Natalya; Chiastra, Claudio; Stremler, Mark A; Sane, David C; Migliavacca, Francesco; Vlachos, Pavlos

    2016-07-01

    Although coronary tortuosity can influence the hemodynamics of coronary arteries, the relationship between tortuosity and flow has not been thoroughly investigated partly due to the absence of a widely accepted definition of tortuosity and the lack of patient-specific studies that analyze complete coronary trees. Using a computational approach we investigated the effects of tortuosity on coronary flow parameters including pressure drop, wall shear stress, and helical flow strength as measured by helicity intensity. Our analysis considered idealized and patient-specific geometries. Overall results indicate that perfusion pressure decreases with increased tortuosity, but the patient-specific results show that more tortuous vessels have higher physiological wall shear stress values. Differences between the idealized and patient-specific results reveal that an accurate representation of coronary tortuosity must account for all relevant geometric aspects, including curvature imposed by the heart shape. The patient-specific results exhibit a strong correlation between tortuosity and helicity intensity, and the corresponding helical flow contributes directly to the observed increase in wall shear stress. Therefore, helicity intensity may prove helpful in developing a universal parameter to describe tortuosity and assess its impact on patient health. Our data suggest that increased tortuosity could have a deleterious impact via a reduction in coronary perfusion pressure, but the attendant increase in wall shear stress could afford protection against atherosclerosis. PMID:26498931

  6. Stereolithography for craniofacial surgery.

    Science.gov (United States)

    Sinn, Douglas P; Cillo, Joseph E; Miles, Brett A

    2006-09-01

    Advances in computer technology have aided in the diagnostic and clinical management of complex congenital craniofacial deformities. The use of stereolithographic models has begun to replace traditional milled models in the treatment of craniofacial deformities. Research has shown that stereolithography models are highly accurate and provide added information in treatment planning for the correction of craniofacial deformities. These include the added visualization of the complex craniofacial anatomy and preoperative surgical planning with a highly accurate three-dimensional model. While the stereolithographic process has had a beneficial impact on the field of craniofacial surgery, the added cost of the procedure continues to be a hindrance to its widespread acceptance in clinical practice. With improved technology and accessibility the utilization of stereolithography in craniofacial surgery is expected to increase. This review will highlight the development and current usage of stereolithography in craniofacial surgery and provide illustration of it use.

  7. After Surgery

    Science.gov (United States)

    ... side effects. There is usually some pain with surgery. There may also be swelling and soreness around ... the first few days, weeks, or months after surgery. Some other questions to ask are How long ...

  8. Turbinate surgery

    Science.gov (United States)

    Turbinectomy; Turbinoplasty; Turbinate reduction; Nasal airway surgery ... There are several types of turbinate surgery: Turbinectomy: All or part of the lower turbinate is taken out. This can be done in several different ways, but sometimes a ...

  9. Computational biomechanics for medicine fundamental science and patient-specific applications

    CERN Document Server

    Miller, Karol; Wittek, Adam; Nielsen, Poul

    2014-01-01

    One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements. This latest installment comprises nine of the latest developments in both fundamental science and patient-specific applications, from researchers in Australia, New Zealand, USA, UK, France, Ireland, and China. Some of the interesting topics discussed are: cellular mechanics; tumor growth and modeling; medical image analysis; and both patient-specific fluid dynamics and solid mechanics simulations.

  10. Evaluation of Constant Thickness Cartilage Models vs. Patient Specific Cartilage Models for an Optimized Computer-Assisted Planning of Periacetabular Osteotomy.

    Directory of Open Access Journals (Sweden)

    Li Liu

    Full Text Available Modern computerized planning tools for periacetabular osteotomy (PAO use either morphology-based or biomechanics-based methods. The latter relies on estimation of peak contact pressures and contact areas using either patient specific or constant thickness cartilage models. We performed a finite element analysis investigating the optimal reorientation of the acetabulum in PAO surgery based on simulated joint contact pressures and contact areas using patient specific cartilage model. Furthermore we investigated the influences of using patient specific cartilage model or constant thickness cartilage model on the biomechanical simulation results. Ten specimens with hip dysplasia were used in this study. Image data were available from CT arthrography studies. Bone models were reconstructed. Mesh models for the patient specific cartilage were defined and subsequently loaded under previously reported boundary and loading conditions. Peak contact pressures and contact areas were estimated in the original position. Afterwards we used a validated preoperative planning software to change the acetabular inclination by an increment of 5° and measured the lateral center edge angle (LCE at each reorientation position. The position with the largest contact area and the lowest peak contact pressure was defined as the optimal position. In order to investigate the influence of using patient specific cartilage model or constant thickness cartilage model on the biomechanical simulation results, the same procedure was repeated with the same bone models but with a cartilage mesh of constant thickness. Comparison of the peak contact pressures and the contact areas between these two different cartilage models showed that good correlation between these two cartilage models for peak contact pressures (r = 0.634 ∈ [0.6, 0.8], p 0.8, p < 0.001. For both cartilage models, the largest contact areas and the lowest peak pressures were found at the same position. Our study is

  11. Heart Surgery Terms

    Science.gov (United States)

    ... Patients Choosing Wisely® Adult Cardiac Surgery What is Pediatric Heart Disease? What is Risk Adjustment? Valve Repair/Replacement Surgery Esophageal Surgery Lung/Thoracic Surgery Aneurysm Surgery Arrhythmia Surgery Other Types of Surgery Clinical ...

  12. [OCAS (Optic and computer aided surgery)].

    Science.gov (United States)

    Rheims, D M; Pflug, L

    1994-12-01

    OCAS is a new, original tool for the diagnosis of dismorphies, both in its conception (digitalisation of a moiré pattern on the body) and in its applications (predominantly surgical, for legal medicine and didactic purposes). By means of this new 3D method of measurement by digitalised moiré, the forms of the body in general, and those of the face in particular, can be studied and quantified with a high degree of accuracy. This precision in the geometrical analysis of its forms is achieved by combining the very latest developments in optics and computer technology. The authors present the current state of their research in the 3D synthesis and manipulation of the human image. PMID:7661561

  13. Three dimensional patient-specific collagen architecture modulates cartilage responses in the knee joint during gait.

    Science.gov (United States)

    Räsänen, Lasse P; Mononen, Mika E; Lammentausta, Eveliina; Nieminen, Miika T; Jurvelin, Jukka S; Korhonen, Rami K

    2016-08-01

    Site-specific variation of collagen fibril orientations can affect cartilage stresses in knee joints. However, this has not been confirmed by 3-D analyses. Therefore, we present a novel method for evaluation of the effect of patient-specific collagen architecture on time-dependent mechanical responses of knee joint cartilage during gait. 3-D finite element (FE) models of a human knee joint were created with the collagen architectures obtained from T2 mapped MRI (patient-specific model) and from literature (literature model). The effect of accuracy of the implementation of collagen fibril architecture into the model was examined by using a submodel with denser FE mesh. Compared to the literature model, fibril strains and maximum principal stresses were reduced especially in the superficial/middle regions of medial tibial cartilage in the patient-specific model after the loading response of gait (up to -413 and -26%, respectively). Compared to the more coarsely meshed joint model, the patient-specific submodel demonstrated similar strain and stress distributions but increased values particularly in the superficial cartilage regions (especially stresses increased >60%). The results demonstrate that implementation of subject-specific collagen architecture of cartilage in 3-D modulates location- and time-dependent mechanical responses of human knee joint cartilage. Submodeling with more accurate implementation of collagen fibril architecture alters cartilage stresses particularly in the superficial/middle tissue. PMID:26714834

  14. Patient-specific dosimetric endpoints based treatment plan quality control in radiotherapy

    Science.gov (United States)

    Song, Ting; Staub, David; Chen, Mingli; Lu, Weiguo; Tian, Zhen; Jia, Xun; Li, Yongbao; Zhou, Linghong; Jiang, Steve B.; Gu, Xuejun

    2015-11-01

    In intensity modulated radiotherapy (IMRT), the optimal plan for each patient is specific due to unique patient anatomy. To achieve such a plan, patient-specific dosimetric goals reflecting each patient’s unique anatomy should be defined and adopted in the treatment planning procedure for plan quality control. This study is to develop such a personalized treatment plan quality control tool by predicting patient-specific dosimetric endpoints (DEs). The incorporation of patient specific DEs is realized by a multi-OAR geometry-dosimetry model, capable of predicting optimal DEs based on the individual patient’s geometry. The overall quality of a treatment plan is then judged with a numerical treatment plan quality indicator and characterized as optimal or suboptimal. Taking advantage of clinically available prostate volumetric modulated arc therapy (VMAT) treatment plans, we built and evaluated our proposed plan quality control tool. Using our developed tool, six of twenty evaluated plans were identified as sub-optimal plans. After plan re-optimization, these suboptimal plans achieved better OAR dose sparing without sacrificing the PTV coverage, and the dosimetric endpoints of the re-optimized plans agreed well with the model predicted values, which validate the predictability of the proposed tool. In conclusion, the developed tool is able to accurately predict optimally achievable DEs of multiple OARs, identify suboptimal plans, and guide plan optimization. It is a useful tool for achieving patient-specific treatment plan quality control.

  15. Validation of a patient-specific one-dimensional model of the systemic arterial tree.

    Science.gov (United States)

    Reymond, Philippe; Bohraus, Yvette; Perren, Fabienne; Lazeyras, Francois; Stergiopulos, Nikos

    2011-09-01

    The aim of this study is to develop and validate a patient-specific distributed model of the systemic arterial tree. This model is built using geometric and hemodynamic data measured on a specific person and validated with noninvasive measurements of flow and pressure on the same person, providing thus a patient-specific model and validation. The systemic arterial tree geometry was obtained from MR angiographic measurements. A nonlinear viscoelastic constitutive law for the arterial wall is considered. Arterial wall distensibility is based on literature data and adapted to match the wave propagation velocity of the main arteries of the specific subject, which were estimated by pressure waves traveling time. The intimal shear stress is modeled using the Witzig-Womersley theory. Blood pressure is measured using applanation tonometry and flow rate using transcranial ultrasound and phase-contrast-MRI. The model predicts pressure and flow waveforms in good qualitative and quantitative agreement with the in vivo measurements, in terms of wave shape and specific wave features. Comparison with a generic one-dimensional model shows that the patient-specific model better predicts pressure and flow at specific arterial sites. These results obtained let us conclude that a patient-specific one-dimensional model of the arterial tree is able to predict well pressure and flow waveforms in the main systemic circulation, whereas this is not always the case for a generic one-dimensional model. PMID:21622820

  16. An effective algorithm for the generation of patient-specific Purkinje networks in computational electrocardiology

    Science.gov (United States)

    Palamara, Simone; Vergara, Christian; Faggiano, Elena; Nobile, Fabio

    2015-02-01

    The Purkinje network is responsible for the fast and coordinated distribution of the electrical impulse in the ventricle that triggers its contraction. Therefore, it is necessary to model its presence to obtain an accurate patient-specific model of the ventricular electrical activation. In this paper, we present an efficient algorithm for the generation of a patient-specific Purkinje network, driven by measures of the electrical activation acquired on the endocardium. The proposed method provides a correction of an initial network, generated by means of a fractal law, and it is based on the solution of Eikonal problems both in the muscle and in the Purkinje network. We present several numerical results both in an ideal geometry with synthetic data and in a real geometry with patient-specific clinical measures. These results highlight an improvement of the accuracy provided by the patient-specific Purkinje network with respect to the initial one. In particular, a cross-validation test shows an accuracy increase of 19% when only the 3% of the total points are used to generate the network, whereas an increment of 44% is observed when a random noise equal to 20% of the maximum value of the clinical data is added to the measures.

  17. Patient-specific dosimetric endpoints based treatment plan quality control in radiotherapy

    International Nuclear Information System (INIS)

    In intensity modulated radiotherapy (IMRT), the optimal plan for each patient is specific due to unique patient anatomy. To achieve such a plan, patient-specific dosimetric goals reflecting each patient’s unique anatomy should be defined and adopted in the treatment planning procedure for plan quality control. This study is to develop such a personalized treatment plan quality control tool by predicting patient-specific dosimetric endpoints (DEs). The incorporation of patient specific DEs is realized by a multi-OAR geometry-dosimetry model, capable of predicting optimal DEs based on the individual patient’s geometry. The overall quality of a treatment plan is then judged with a numerical treatment plan quality indicator and characterized as optimal or suboptimal. Taking advantage of clinically available prostate volumetric modulated arc therapy (VMAT) treatment plans, we built and evaluated our proposed plan quality control tool. Using our developed tool, six of twenty evaluated plans were identified as sub-optimal plans. After plan re-optimization, these suboptimal plans achieved better OAR dose sparing without sacrificing the PTV coverage, and the dosimetric endpoints of the re-optimized plans agreed well with the model predicted values, which validate the predictability of the proposed tool. In conclusion, the developed tool is able to accurately predict optimally achievable DEs of multiple OARs, identify suboptimal plans, and guide plan optimization. It is a useful tool for achieving patient-specific treatment plan quality control. (paper)

  18. 急诊外科创伤患者病死的危险因素及急救措施%Risk factors of mortality in patients with trauma in emergency surgery and first aid measures

    Institute of Scientific and Technical Information of China (English)

    张永亮

    2016-01-01

    目的:探讨分析引起急诊外科创伤患者病死因素及相关急救措施。方法对本院急诊外科2012年11月至2015年10月收治的156例创伤死亡患者进行回顾分析,统计患者资料,利用Logistic分析对可能引起创伤患者死亡的因素进行研究分析。结果20岁以上的创伤死亡患者占75.64%,为急诊创伤死亡主要人群。91例患者有多处创伤,多发率为58.33%,创伤集中部位主要为腹部、胸部及头部,101例患者院前抢救无效,院前死亡率占64.74%。从致伤原因分析,以交通事故、高空坠落创伤致死为主,分占60.26%、25.00%,Logistic多因素分析显示,创伤患者年龄、现场急救、机械通气及GCS评分、ISS评分是引起创伤患者病死的主要危险因素。结论医疗机构应该建立专业的急救团队及系统、迅速的应急机制,强化院前急救与院内急诊的急救水平,保证创伤患者可以第一时间得到救治,以提高急救成功率。%Objective To investigate and analyze the factors that cause the death of trauma patients in emergency surgery and related emergency measures. Methods Retrospective analysis of 156 cases of trauma deaths in our hospital from October 2015 to November 2012 in our hospital, statistical data of patients, using Logistic analysis to analyze the fac-tors that may cause the death of trauma patients. Results Trauma deaths accounted for 20 of patients over the age of 75.64%, and the major population of emergency trauma deaths. 91 cases of patients with multiple trauma, multiple rate was 58.33%, the trauma focused on the main parts of the abdomen, chest and head, 101 cases of patients with pre hospital res-cue is invalid, the pre hospital mortality rate was 64.74%. Analysis of the causes of injury, traffic accidents, injuries to the upper air crash deaths, accounting for 60.26%, 25%, Logistic multi factor analysis showed that the age of trauma patients, on-site first aid

  19. Hearing Aids

    Science.gov (United States)

    ... prefer the open-fit hearing aid because their perception of their voice does not sound “plugged up.” ... My voice sounds too loud. The “plugged-up” sensation that causes a hearing aid user’s voice to ...

  20. Brand Aid

    DEFF Research Database (Denmark)

    Richey, Lisa Ann; Ponte, Stefano

    A critical account of the rise of celebrity-driven “compassionate consumption” Cofounded by the rock star Bono in 2006, Product RED exemplifies a new trend in celebrity-driven international aid and development, one explicitly linked to commerce, not philanthropy. Brand Aid offers a deeply informed...

  1. Strabismus Surgery

    Science.gov (United States)

    ... used. Some surgeons prescribe an antibiotic or combination antibiotic/steroid drop or ointment after surgery. More technical ... Screening Recommendations Loading... Most Common Searches Adult ...

  2. Corrective Jaw Surgery

    Science.gov (United States)

    ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of ...

  3. [Evolution of total knee arthroplasty : From robotics and navigation to patient-specific instruments].

    Science.gov (United States)

    Haaker, R

    2016-04-01

    In this article the evolution beginning with the robotics of total knee arthroplasty to CT-based and kinematic navigation and patient-specific instruments is described. Thereby it is pointed out that in the early 1990s, CT imaging solely for the planning of a knee endoprosthesis was considered as obsolete radiation exposure and this led to the widespread development of kinematical systems.Also a patient specific planning tool based on CAD built acryl harz blocs existed at the time. There is an ongoing process of implanting total knee arthroplasties in a more exact position. Nowadays the new evolution of soft tissue balancing by using a kinematic alignment has put these efforts into perspective. PMID:27025867

  4. Predictive Models with Patient Specific Material Properties for the Biomechanical Behavior of Ascending Thoracic Aneurysms.

    Science.gov (United States)

    Trabelsi, Olfa; Duprey, Ambroise; Favre, Jean-Pierre; Avril, Stéphane

    2016-01-01

    The aim of this study is to identify the patient-specific material properties of ascending thoracic aortic aneurysms (ATAA) using preoperative dynamic gated computed tomography (CT) scans. The identification is based on the simultaneous minimization of two cost functions, which define the difference between model predictions and gated CT measurements of the aneurysm volume at respectively systole and cardiac mid-cycle. The method is applied on five patients who underwent surgical repair of their ATAA at the University Hospital Center of St. Etienne. For these patients, the aneurysms were collected and tested mechanically using an in vitro bench. For the sake of validation, the mechanical properties found using the in vivo approach and the in vitro bench were compared. We eventually performed finite-element stress analyses based on each set of material properties. Rupture risk indexes were estimated and compared, showing promising results of the patient-specific identification method based on gated CT. PMID:26178871

  5. Review of patient-specific simulations of transcatheter aortic valve implantation

    OpenAIRE

    Vy, P; Auffret, Vincent; Badel, Pierre; Rochette, Michel; Le Breton, Hervé; Haigron, Pascal; Avril, Stéphane

    2016-01-01

    International audience Transcatheter Aortic Valve Implantation (TAVI) accounts for one of the most promising new cardiovascular procedures. This minimally invasive technique is still at its early stage and is constantly developing thanks to imaging techniques, computer science, biomechanics and technologies of prosthesis and delivery tools. As a result, patient-specific simulation can find an exciting playground in TAVI. It canexpress its potential by providing the clinicians with powerful...

  6. MMCTP: a radiotherapy research environment for Monte Carlo and patient-specific treatment planning

    International Nuclear Information System (INIS)

    Radiotherapy research lacks a flexible computational research environment for Monte Carlo (MC) and patient-specific treatment planning. The purpose of this study was to develop a flexible software package on low-cost hardware with the aim of integrating new patient-specific treatment planning with MC dose calculations suitable for large-scale prospective and retrospective treatment planning studies. We designed the software package 'McGill Monte Carlo treatment planning' (MMCTP) for the research development of MC and patient-specific treatment planning. The MMCTP design consists of a graphical user interface (GUI), which runs on a simple workstation connected through standard secure-shell protocol to a cluster for lengthy MC calculations. Treatment planning information (e.g., images, structures, beam geometry properties and dose distributions) is converted into a convenient MMCTP local file storage format designated, the McGill RT format. MMCTP features include (a) DICOMRT, RTOG and CADPlan CART format imports; (b) 2D and 3D visualization views for images, structure contours, and dose distributions; (c) contouring tools; (d) DVH analysis, and dose matrix comparison tools; (e) external beam editing; (f) MC transport calculation from beam source to patient geometry for photon and electron beams. The MC input files, which are prepared from the beam geometry properties and patient information (e.g., images and structure contours), are uploaded and run on a cluster using shell commands controlled from the MMCTP GUI. The visualization, dose matrix operation and DVH tools offer extensive options for plan analysis and comparison between MC plans and plans imported from commercial treatment planning systems. The MMCTP GUI provides a flexible research platform for the development of patient-specific MC treatment planning for photon and electron external beam radiation therapy. The impact of this tool lies in the fact that it allows for systematic, platform-independent, large

  7. The utility of patient specific induced pluripotent stem cells for the modelling of Autistic Spectrum Disorders

    OpenAIRE

    Cocks, Graham; Curran, Sarah; Gami, Priya; Uwanogho, Dafe; Jeffries, Aaron R.; Kathuria, Annie; Lucchesi, Walter; Wood, Victoria; Dixon, Rosemary; Ogilvie, Caroline; Steckler, Thomas; Price, Jack

    2013-01-01

    Until now, models of psychiatric diseases have typically been animal models. Whether they were to be used to further understand the pathophysiology of the disorder, or as drug discovery tools, animal models have been the choice of preference in mimicking psychiatric disorders in an experimental setting. While there have been cellular models, they have generally been lacking in validity. This situation is changing with the advent of patient-specific induced pluripotent stem cells (iPSCs). In t...

  8. Patient-specific simulations of stenting procedures in coronary bifurcations: two clinical cases.

    Science.gov (United States)

    Morlacchi, Stefano; Colleoni, Sebastian George; Cárdenes, Rubén; Chiastra, Claudio; Diez, Jose Luis; Larrabide, Ignacio; Migliavacca, Francesco

    2013-09-01

    Computational simulations of stenting procedures in idealized geometries can only provide general guidelines and their use in the patient-specific planning of percutaneous treatments is inadequate. Conversely, image-based patient-specific tools that are able to realistically simulate different interventional options might facilitate clinical decision-making and provide useful insights on the treatment for each individual patient. The aim of this work is the implementation of a patient-specific model that uses image-based reconstructions of coronary bifurcations and is able to replicate real stenting procedures following clinical indications. Two clinical cases are investigated focusing the attention on the open problems of coronary bifurcations and their main treatment, the provisional side branch approach. Image-based reconstructions are created combining the information from conventional coronary angiography and computed tomography angiography while structural finite element models are implemented to replicate the real procedure performed in the patients. First, numerical results show the biomechanical influence of stents deployment in the coronary bifurcations during and after the procedures. In particular, the straightening of the arterial wall and the influence of two overlapping stents on stress fields are investigated here. Results show that a sensible decrease of the vessel tortuosity occurs after stent implantation and that overlapping devices result in an increased stress state of both the artery and the stents. Lastly, the comparison between numerical and image-based post-stenting configurations proved the reliability of such models while replicating stent deployment in coronary arteries.

  9. Effects of segmentation on patient-specific numerical simulation of cerebral aneurysm hemodynamics

    Science.gov (United States)

    Venugopal, Prem; Schmitt, Holger; Duckwiler, Gary R.; Valentino, Daniel J.

    2006-03-01

    One of the factors affecting the accuracy of patient-specific, imaging-based computational hemodynamic studies is the accuracy of geometric models created from medical images. In the present study we have investigated as to how accurate the geometric models should be in the context of cerebral aneurysms in order to obtain an accurate reproduction of intra-aneurysmal hemodynamics in individual patients using numerical simulations. Computed tomography angiography (CTA) images obtained for a patient-specific anterior communicating artery (ACoA) aneurysm and a patient-specific middle cerebral artery (MCA) aneurysm were used to construct the geometric models. For each aneurysm, two models were created, one using a different threshold value for image segmentation than the other. The average distance between the models was about the size of one in-plane pixel. It was found that for the MCA aneurysm, the simulated pressure and shear stress distributions for the two models were entirely different while for the ACoA aneurysm the mean pressure distribution obtained for the two models were similar, but the shear stress distributions were completely different. These results indicate that accurate reproduction of intra-aneurysmal hemodynamics would require the geometric reconstruction from medical images to be highly accurate.

  10. A Patient-Specific Airway Branching Model for Mechanically Ventilated Patients

    Directory of Open Access Journals (Sweden)

    Nor Salwa Damanhuri

    2014-01-01

    Full Text Available Background. Respiratory mechanics models have the potential to guide mechanical ventilation. Airway branching models (ABMs were developed from classical fluid mechanics models but do not provide accurate models of in vivo behaviour. Hence, the ABM was improved to include patient-specific parameters and better model observed behaviour (ABMps. Methods. The airway pressure drop of the ABMps was compared with the well-accepted dynostatic algorithm (DSA in patients diagnosed with acute respiratory distress syndrome (ARDS. A scaling factor (α was used to equate the area under the pressure curve (AUC from the ABMps to the AUC of the DSA and was linked to patient state. Results. The ABMps recorded a median α value of 0.58 (IQR: 0.54–0.63; range: 0.45–0.66 for these ARDS patients. Significantly lower α values were found for individuals with chronic obstructive pulmonary disease (P<0.001. Conclusion. The ABMps model allows the estimation of airway pressure drop at each bronchial generation with patient-specific physiological measurements and can be generated from data measured at the bedside. The distribution of patient-specific α values indicates that the overall ABM can be readily improved to better match observed data and capture patient condition.

  11. The effect of inlet waveforms on computational hemodynamics of patient-specific intracranial aneurysms.

    Science.gov (United States)

    Xiang, J; Siddiqui, A H; Meng, H

    2014-12-18

    Due to the lack of patient-specific inlet flow waveform measurements, most computational fluid dynamics (CFD) simulations of intracranial aneurysms usually employ waveforms that are not patient-specific as inlet boundary conditions for the computational model. The current study examined how this assumption affects the predicted hemodynamics in patient-specific aneurysm geometries. We examined wall shear stress (WSS) and oscillatory shear index (OSI), the two most widely studied hemodynamic quantities that have been shown to predict aneurysm rupture, as well as maximal WSS (MWSS), energy loss (EL) and pressure loss coefficient (PLc). Sixteen pulsatile CFD simulations were carried out on four typical saccular aneurysms using 4 different waveforms and an identical inflow rate as inlet boundary conditions. Our results demonstrated that under the same mean inflow rate, different waveforms produced almost identical WSS distributions and WSS magnitudes, similar OSI distributions but drastically different OSI magnitudes. The OSI magnitude is correlated with the pulsatility index of the waveform. Furthermore, there is a linear relationship between aneurysm-averaged OSI values calculated from one waveform and those calculated from another waveform. In addition, different waveforms produced similar MWSS, EL and PLc in each aneurysm. In conclusion, inlet waveform has minimal effects on WSS, OSI distribution, MWSS, EL and PLc and a strong effect on OSI magnitude, but aneurysm-averaged OSI from different waveforms has a strong linear correlation with each other across different aneurysms, indicating that for the same aneurysm cohort, different waveforms can consistently stratify (rank) OSI of aneurysms. PMID:25446264

  12. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

    Science.gov (United States)

    Canals, Isaac; Soriano, Jordi; Orlandi, Javier G.; Torrent, Roger; Richaud-Patin, Yvonne; Jiménez-Delgado, Senda; Merlin, Simone; Follenzi, Antonia; Consiglio, Antonella; Vilageliu, Lluïsa; Grinberg, Daniel; Raya, Angel

    2015-01-01

    Summary Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration. PMID:26411903

  13. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

    Directory of Open Access Journals (Sweden)

    Isaac Canals

    2015-10-01

    Full Text Available Induced pluripotent stem cell (iPSC technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration.

  14. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks.

    Science.gov (United States)

    Canals, Isaac; Soriano, Jordi; Orlandi, Javier G; Torrent, Roger; Richaud-Patin, Yvonne; Jiménez-Delgado, Senda; Merlin, Simone; Follenzi, Antonia; Consiglio, Antonella; Vilageliu, Lluïsa; Grinberg, Daniel; Raya, Angel

    2015-10-13

    Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration.

  15. Hearing Aid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A man realized that he needed to purchase ahearing aid, but he was unwilling to spend muchmoney. "How much do they run?"he asked theclerk. "That depends," said. the salesman. "Theyrun from 2 to 2000."

  16. Hearing Aid

    Science.gov (United States)

    ... and Food and Drug Administration Staff FDA permits marketing of new laser-based hearing aid with potential ... feeds Follow FDA on Twitter Follow FDA on Facebook View FDA videos on YouTube View FDA photos ...

  17. Improved Surgery Planning Using 3-D Printing: a Case Study.

    Science.gov (United States)

    Singhal, A J; Shetty, V; Bhagavan, K R; Ragothaman, Ananthan; Shetty, V; Koneru, Ganesh; Agarwala, M

    2016-04-01

    The role of 3-D printing is presented for improved patient-specific surgery planning. Key benefits are time saved and surgery outcome. Two hard-tissue surgery models were 3-D printed, for orthopedic, pelvic surgery, and craniofacial surgery. We discuss software data conversion in computed tomography (CT)/magnetic resonance (MR) medical image for 3-D printing. 3-D printed models save time in surgery planning and help visualize complex pre-operative anatomy. Time saved in surgery planning can be as much as two thirds. In addition to improved surgery accuracy, 3-D printing presents opportunity in materials research. Other hard-tissue and soft-tissue cases in maxillofacial, abdominal, thoracic, cardiac, orthodontics, and neurosurgery are considered. We recommend using 3-D printing as standard protocol for surgery planning and for teaching surgery practices. A quick turnaround time of a 3-D printed surgery model, in improved accuracy in surgery planning, is helpful for the surgery team. It is recommended that these costs be within 20 % of the total surgery budget. PMID:27303117

  18. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft.

    LENUS (Irish Health Repository)

    Molony, David S

    2009-01-01

    BACKGROUND: Abdominal aortic aneurysms (AAA) are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI) is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. METHODS: Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. RESULTS: Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. CONCLUSION: In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  19. Fluid-structure interaction of a patient-specific abdominal aortic aneurysm treated with an endovascular stent-graft

    Directory of Open Access Journals (Sweden)

    McGloughlin Tim M

    2009-10-01

    Full Text Available Abstract Background Abdominal aortic aneurysms (AAA are local dilatations of the infrarenal aorta. If left untreated they may rupture and lead to death. One form of treatment is the minimally invasive insertion of a stent-graft into the aneurysm. Despite this effective treatment aneurysms may occasionally continue to expand and this may eventually result in post-operative rupture of the aneurysm. Fluid-structure interaction (FSI is a particularly useful tool for investigating aneurysm biomechanics as both the wall stresses and fluid forces can be examined. Methods Pre-op, Post-op and Follow-up models were reconstructed from CT scans of a single patient and FSI simulations were performed on each model. The FSI approach involved coupling Abaqus and Fluent via a third-party software - MpCCI. Aneurysm wall stress and compliance were investigated as well as the drag force acting on the stent-graft. Results Aneurysm wall stress was reduced from 0.38 MPa before surgery to a value of 0.03 MPa after insertion of the stent-graft. Higher stresses were seen in the aneurysm neck and iliac legs post-operatively. The compliance of the aneurysm was also reduced post-operatively. The peak Post-op axial drag force was found to be 4.85 N. This increased to 6.37 N in the Follow-up model. Conclusion In a patient-specific case peak aneurysm wall stress was reduced by 92%. Such a reduction in aneurysm wall stress may lead to shrinkage of the aneurysm over time. Hence, post-operative stress patterns may help in determining the likelihood of aneurysm shrinkage post EVAR. Post-operative remodelling of the aneurysm may lead to increased drag forces.

  20. Virtual 3D planning and patient specific surgical guides for osteotomies around the knee: a feasibility and proof-of-concept study.

    Science.gov (United States)

    Victor, J; Premanathan, A

    2013-11-01

    We have investigated the benefits of patient specific instrument guides, applied to osteotomies around the knee. Single, dual and triple planar osteotomies were performed on tibias or femurs in 14 subjects. In all patients, a detailed pre-operative plan was prepared based upon full leg standing radiographic and CT scan information. The planned level of the osteotomy and open wedge resection was relayed to the surgery by virtue of a patient specific guide developed from the images. The mean deviation between the planned wedge angle and the executed wedge angle was 0° (-1 to 1, sd 0.71) in the coronal plane and 0.3° (-0.9 to 3, sd 1.14) in the sagittal plane. The mean deviation between the planned hip, knee, ankle angle (HKA) on full leg standing radiograph and the post-operative HKA was 0.3° (-1 to 2, sd 0.75). It is concluded that this is a feasible and valuable concept from the standpoint of pre-operative software based planning, surgical application and geometrical accuracy of outcome. PMID:24187376

  1. [Partial replacement of the knee joint with patient-specific instruments and implants (ConforMIS iUni, iDuo)].

    Science.gov (United States)

    Beckmann, J; Steinert, A; Zilkens, C; Zeh, A; Schnurr, C; Schmitt-Sody, M; Gebauer, M

    2016-04-01

    Knee arthroplasty is a successful standard procedure in orthopedic surgery; however, approximately 20 % of patients are dissatisfied with the clinical results as they suffer pain and can no longer achieve the presurgery level of activity. According to the literature the reasons are inexact fitting of the prosthesis or too few anatomically formed implants resulting in less physiological kinematics of the knee joint. Reducing the number of dissatisfied patients and the corresponding number of revisions is an important goal considering the increasing need for artificial joints. In this context, patient-specific knee implants are an obvious alternative to conventional implants. For the first time implants are now matched to the individual bone and not vice versa to achieve the best possible individual situation and geometry and more structures (e.g. ligaments and bone) are preserved or only those structures are replaced which were actually destroyed by arthrosis. According to the authors view, this represents an optimal and pioneering addition to conventional implants. Patient-specific implants and the instruments needed for correct alignment and fitting can be manufactured by virtual 3D reconstruction and 3D printing based on computed tomography (CT) scans. The portfolio covers medial as well as lateral unicondylar implants, medial as well as lateral bicompartmental implants (femorotibial and patellofemoral compartments) and cruciate ligament-preserving as well as cruciate ligament-substituting total knee replacements; however, it must be explicitly emphasized that the literature is sparse and no long-term data are available. PMID:26984107

  2. The patient's perspective of the feasibility of a patient-specific instrument in physiotherapy goal setting : a qualitative study

    NARCIS (Netherlands)

    Stevens, Anita; Moser, Albine; Köke, Albère; Weijden, Trudy van der; Beurskens, Anna

    2016-01-01

    Background: Patient participation in goal setting is important to deliver client-centered care. In daily practice, however, patient involvement in goal setting is not optimal. Patient-specific instruments, such as the Patient Specific Complaints (PSC) instrument, can support the goal-setting process

  3. Types of Hearing Aids

    Science.gov (United States)

    ... Devices Consumer Products Hearing Aids Types of Hearing Aids Share Tweet Linkedin Pin it More sharing options ... some features for hearing aids? What are hearing aids? Hearing aids are sound-amplifying devices designed to ...

  4. In Vitro Validation of Patient-Specific Hemodynamic Simulations in Coronary Aneurysms Caused by Kawasaki Disease.

    Science.gov (United States)

    Kung, Ethan; Kahn, Andrew M; Burns, Jane C; Marsden, Alison

    2014-06-01

    To perform experimental validation of computational fluid dynamics (CFD) applied to patient specific coronary aneurysm anatomy of Kawasaki disease. We quantified hemodynamics in a patient-specific coronary artery aneurysm physical phantom under physiologic rest and exercise flow conditions. Using phase contrast MRI (PCMRI), we acquired 3-component flow velocity at two slice locations in the aneurysms. We then performed numerical simulations with the same geometry and inflow conditions, and performed qualitative and quantitative comparisons of velocities between experimental measurements and simulation results. We observed excellent qualitative agreement in flow pattern features. The quantitative spatially and temporally varying differences in velocity between PCMRI and CFD were proportional to the flow velocity. As a result, the percent discrepancy between simulation and experiment was relatively constant regardless of flow velocity variations. Through 1D and 2D quantitative comparisons, we found a 5-17% difference between measured and simulated velocities. Additional analysis assessed wall shear stress differences between deformable and rigid wall simulations. This study demonstrated that CFD produced good qualitative and quantitative predictions of velocities in a realistic coronary aneurysm anatomy under physiological flow conditions. The results provide insights on factors that may influence the level of agreement, and a set of in vitro experimental data that can be used by others to compare against CFD simulation results. The findings of this study increase confidence in the use of CFD for investigating hemodynamics in the specialized anatomy of coronary aneurysms. This provides a basis for future hemodynamics studies in patient-specific models of Kawasaki disease. PMID:25050140

  5. Patient-specific coronary artery blood flow simulation using myocardial volume partitioning

    Science.gov (United States)

    Kim, Kyung Hwan; Kang, Dongwoo; Kang, Nahyup; Kim, Ji-Yeon; Lee, Hyong-Euk; Kim, James D. K.

    2013-03-01

    Using computational simulation, we can analyze cardiovascular disease in non-invasive and quantitative manners. More specifically, computational modeling and simulation technology has enabled us to analyze functional aspect such as blood flow, as well as anatomical aspect such as stenosis, from medical images without invasive measurements. Note that the simplest ways to perform blood flow simulation is to apply patient-specific coronary anatomy with other average-valued properties; in this case, however, such conditions cannot fully reflect accurate physiological properties of patients. To resolve this limitation, we present a new patient-specific coronary blood flow simulation method by myocardial volume partitioning considering artery/myocardium structural correspondence. We focus on that blood supply is closely related to the mass of each myocardial segment corresponding to the artery. Therefore, we applied this concept for setting-up simulation conditions in the way to consider many patient-specific features as possible from medical image: First, we segmented coronary arteries and myocardium separately from cardiac CT; then the myocardium is partitioned into multiple regions based on coronary vasculature. The myocardial mass and required blood mass for each artery are estimated by converting myocardial volume fraction. Finally, the required blood mass is used as boundary conditions for each artery outlet, with given average aortic blood flow rate and pressure. To show effectiveness of the proposed method, fractional flow reserve (FFR) by simulation using CT image has been compared with invasive FFR measurement of real patient data, and as a result, 77% of accuracy has been obtained.

  6. Calculating patient specific doses in X-ray diagnostics and from radiopharmaceuticals

    International Nuclear Information System (INIS)

    The risk associated with exposure to ionising radiation is dependent on the characteristics of the exposed individual. The size and structure of the individual influences the absorbed dose distribution in the organs. Traditional methods used to calculate the patient organ doses are based on standardised calculation phantoms, which neglect the variance of the patient size or even sex. When estimating the radiation dose of an individual patient, patient specific calculation methods must be used. Methods for patient specific dosimetry in the fields of X-ray diagnostics and diagnostic and therapeutic use of radiopharmaceuticals were proposed in this thesis. A computer program, ODS-60, for calculating organ doses from diagnostic X-ray exposures was presented. The calculation is done in a patient specific phantom with depth dose and profile algorithms fitted to Monte Carlo simulation data from a previous study. Improvements to the version reported earlier were introduced, e.g. bone attenuation was implemented. The applicability of the program to determine patient doses from complex X-ray examinations (barium enema examination) was studied. The conversion equations derived for female and male patients as a function of patient weight gave the smallest deviation from the actual patient doses when compared to previous studies. Another computer program, Intdose, was presented for calculation of the dose distribution from radiopharmaceuticals. The calculation is based on convolution of an isotope specific point dose kernel with activity distribution, obtained from single photon emission computed tomography (SPECT) images. Anatomical information is taken from magnetic resonance (MR) or computed tomography (CT) images. According to a phantom study, Intdose agreed within 3 % with measurements. For volunteers administered diagnostic radiopharmaceuticals, the results given by Intdose were found to agree with traditional methods in cases of medium sized patients. For patients

  7. Generation of Transplantable Beta Cells for Patient-Specific Cell Therapy

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2012-01-01

    Full Text Available Islet cell transplantation offers a potential cure for type 1 diabetes, but it is challenged by insufficient donor tissue and side effects of current immunosuppressive drugs. Therefore, alternative sources of insulin-producing cells and isletfriendly immunosuppression are required to increase the efficiency and safety of this procedure. Beta cells can be transdifferentiated from precursors or another heterologous (non-beta-cell source. Recent advances in beta cell regeneration from somatic cells such as fibroblasts could circumvent the usage of immunosuppressive drugs. Therefore, generation of patient-specific beta cells provides the potential of an evolutionary treatment for patients with diabetes.

  8. Creating Patient-Specific Neural Cells for the In Vitro Study of Brain Disorders.

    Science.gov (United States)

    Brennand, Kristen J; Marchetto, M Carol; Benvenisty, Nissim; Brüstle, Oliver; Ebert, Allison; Izpisua Belmonte, Juan Carlos; Kaykas, Ajamete; Lancaster, Madeline A; Livesey, Frederick J; McConnell, Michael J; McKay, Ronald D; Morrow, Eric M; Muotri, Alysson R; Panchision, David M; Rubin, Lee L; Sawa, Akira; Soldner, Frank; Song, Hongjun; Studer, Lorenz; Temple, Sally; Vaccarino, Flora M; Wu, Jun; Vanderhaeghen, Pierre; Gage, Fred H; Jaenisch, Rudolf

    2015-12-01

    As a group, we met to discuss the current challenges for creating meaningful patient-specific in vitro models to study brain disorders. Although the convergence of findings between laboratories and patient cohorts provided us confidence and optimism that hiPSC-based platforms will inform future drug discovery efforts, a number of critical technical challenges remain. This opinion piece outlines our collective views on the current state of hiPSC-based disease modeling and discusses what we see to be the critical objectives that must be addressed collectively as a field.

  9. Creating Patient-Specific Neural Cells for the In Vitro Study of Brain Disorders

    Directory of Open Access Journals (Sweden)

    Kristen J. Brennand

    2015-12-01

    Full Text Available As a group, we met to discuss the current challenges for creating meaningful patient-specific in vitro models to study brain disorders. Although the convergence of findings between laboratories and patient cohorts provided us confidence and optimism that hiPSC-based platforms will inform future drug discovery efforts, a number of critical technical challenges remain. This opinion piece outlines our collective views on the current state of hiPSC-based disease modeling and discusses what we see to be the critical objectives that must be addressed collectively as a field.

  10. Rhabdomyosarcoma: Surgery

    Science.gov (United States)

    ... plastic surgeons, maxillofacial surgeons, and neurosurgeons. If a tumor is large or is in a spot where removing it completely would severely affect the child’s appearance or cause other problems, then surgery may be ...

  11. Brain surgery

    Science.gov (United States)

    Craniotomy; Surgery - brain; Neurosurgery; Craniectomy; Stereotactic craniotomy; Stereotactic brain biopsy; Endoscopic craniotomy ... cut depends on where the problem in the brain is located. The surgeon creates a hole in ...

  12. Oesophageal surgery

    Institute of Scientific and Technical Information of China (English)

    Erik J. Simchuk; Derek Alderson

    2001-01-01

    @@INTRODUCTION The origins of oesophageal surgery ,like most surgical treatments ,are based in the treatment of traumatic injury .The Smith Surgical Papyrus describes the examination, diagnosis and treatment of "a gaping wound of throat, penetrating the gullet" [1].

  13. Negotiating Aid

    DEFF Research Database (Denmark)

    Whitfield, Lindsay; Fraser, Alastair

    2011-01-01

    This article presents a new analytical approach to the study of aid negotiations. Building on existing approaches but trying to overcome their limitations, it argues that factors outside of individual negotiations (or the `game' in game-theoretic approaches) significantly affect the preferences...... which investigated the strategies these states have adopted in talks with aid donors, the sources of leverage they have been able to bring to bear in negotiations, and the differing degrees of control that they have been able to exercise over the policies agreed in negotiations and those implemented...

  14. Acne Surgery

    OpenAIRE

    Dilworth, G. R.

    1983-01-01

    Acne surgery consists of comedone extraction of non-inflamed lesions, triamcinolone acetate injections of some inflamed lesions, and extraction of milia. Prevention is a very important part of comedone treatment, especially avoidance of picking, moisturizers and harsh soaps. Instruments are also very important: even the finest may be too thick and may have to be filed down. Acne surgery is only an adjunct of good medical therapy.

  15. Tennis elbow surgery

    Science.gov (United States)

    Lateral epicondylitis - surgery; Lateral tendinosis - surgery; Lateral tennis elbow - surgery ... Surgery to repair tennis elbow is usually an outpatient surgery. This means you will not stay in the hospital overnight. You will be ...

  16. Brand Aid

    DEFF Research Database (Denmark)

    Richey, Lisa Ann; Ponte, Stefano

    2011-01-01

    activists, scholars and venture capitalists, discusses the pros and cons of changing the world by ‘voting with your dollars’. Lisa Ann Richey and Stefano Ponte (Professor at Roskilde University and Senior Researcher at DIIS respectively), authors of Brand Aid: Shopping Well to Save the World, highlight how...

  17. Automated segmentation and reconstruction of patient-specific cardiac anatomy and pathology from in vivo MRI

    International Nuclear Information System (INIS)

    This paper presents an automated method to segment left ventricle (LV) tissues from functional and delayed-enhancement (DE) cardiac magnetic resonance imaging (MRI) scans using a sequential multi-step approach. First, a region of interest (ROI) is computed to create a subvolume around the LV using morphological operations and image arithmetic. From the subvolume, the myocardial contours are automatically delineated using difference of Gaussians (DoG) filters and GSV snakes. These contours are used as a mask to identify pathological tissues, such as fibrosis or scar, within the DE-MRI. The presented automated technique is able to accurately delineate the myocardium and identify the pathological tissue in patient sets. The results were validated by two expert cardiologists, and in one set the automated results are quantitatively and qualitatively compared with expert manual delineation. Furthermore, the method is patient-specific, performed on an entire patient MRI series. Thus, in addition to providing a quick analysis of individual MRI scans, the fully automated segmentation method is used for effectively tagging regions in order to reconstruct computerized patient-specific 3D cardiac models. These models can then be used in electrophysiological studies and surgical strategy planning. (paper)

  18. Towards Patient-Specific Modeling of Coronary Hemodynamics in Healthy and Diseased State

    Directory of Open Access Journals (Sweden)

    Arjen van der Horst

    2013-01-01

    Full Text Available A model describing the primary relations between the cardiac muscle and coronary circulation might be useful for interpreting coronary hemodynamics in case multiple types of coronary circulatory disease are present. The main contribution of the present study is the coupling of a microstructure-based heart contraction model with a 1D wave propagation model. The 1D representation of the vessels enables patient-specific modeling of the arteries and/or can serve as boundary conditions for detailed 3D models, while the heart model enables the simulation of cardiac disease, with physiology-based parameter changes. Here, the different components of the model are explained and the ability of the model to describe coronary hemodynamics in health and disease is evaluated. Two disease types are modeled: coronary epicardial stenoses and left ventricular hypertrophy with an aortic valve stenosis. In all simulations (healthy and diseased, the dynamics of pressure and flow qualitatively agreed with observations described in literature. We conclude that the model adequately can predict coronary hemodynamics in both normal and diseased state based on patient-specific clinical data.

  19. Accuracy of Computational Cerebral Aneurysm Hemodynamics Using Patient-Specific Endovascular Measurements

    Science.gov (United States)

    McGah, Patrick; Levitt, Michael; Barbour, Michael; Mourad, Pierre; Kim, Louis; Aliseda, Alberto

    2013-11-01

    We study the hemodynamic conditions in patients with cerebral aneurysms through endovascular measurements and computational fluid dynamics. Ten unruptured cerebral aneurysms were clinically assessed by three dimensional rotational angiography and an endovascular guidewire with dual Doppler ultrasound transducer and piezoresistive pressure sensor at multiple peri-aneurysmal locations. These measurements are used to define boundary conditions for flow simulations at and near the aneurysms. The additional in vivo measurements, which were not prescribed in the simulation, are used to assess the accuracy of the simulated flow velocity and pressure. We also performed simulations with stereotypical literature-derived boundary conditions. Simulated velocities using patient-specific boundary conditions showed good agreement with the guidewire measurements, with no systematic bias and a random scatter of about 25%. Simulated velocities using the literature-derived values showed a systematic over-prediction in velocity by 30% with a random scatter of about 40%. Computational hemodynamics using endovascularly-derived patient-specific boundary conditions have the potential to improve treatment predictions as they provide more accurate and precise results of the aneurysmal hemodynamics. Supported by an R03 grant from NIH/NINDS

  20. Computational Simulations of Inferior Vena Cava (IVC) Filter Placement and Hemodynamics in Patient-Specific Geometries

    Science.gov (United States)

    Aycock, Kenneth; Sastry, Shankar; Kim, Jibum; Shontz, Suzanne; Campbell, Robert; Manning, Keefe; Lynch, Frank; Craven, Brent

    2013-11-01

    A computational methodology for simulating inferior vena cava (IVC) filter placement and IVC hemodynamics was developed and tested on two patient-specific IVC geometries: a left-sided IVC, and an IVC with a retroaortic left renal vein. Virtual IVC filter placement was performed with finite element analysis (FEA) using non-linear material models and contact modeling, yielding maximum vein displacements of approximately 10% of the IVC diameters. Blood flow was then simulated using computational fluid dynamics (CFD) with four cases for each patient IVC: 1) an IVC only, 2) an IVC with a placed filter, 3) an IVC with a placed filter and a model embolus, all at resting flow conditions, and 4) an IVC with a placed filter and a model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet (all cases) and a larger stagnation region (cases 3-4) in the left-sided IVC. These results support further investigation of the effects of IVC filter placement on a patient-specific basis.

  1. Effect of voxel size when calculating patient specific radionuclide dosimetry estimates using direct Monte Carlo simulation.

    Science.gov (United States)

    Hickson, Kevin J; O'Keefe, Graeme J

    2014-09-01

    The scalable XCAT voxelised phantom was used with the GATE Monte Carlo toolkit to investigate the effect of voxel size on dosimetry estimates of internally distributed radionuclide calculated using direct Monte Carlo simulation. A uniformly distributed Fluorine-18 source was simulated in the Kidneys of the XCAT phantom with the organ self dose (kidney ← kidney) and organ cross dose (liver ← kidney) being calculated for a number of organ and voxel sizes. Patient specific dose factors (DF) from a clinically acquired FDG PET/CT study have also been calculated for kidney self dose and liver ← kidney cross dose. Using the XCAT phantom it was found that significantly small voxel sizes are required to achieve accurate calculation of organ self dose. It has also been used to show that a voxel size of 2 mm or less is suitable for accurate calculations of organ cross dose. To compensate for insufficient voxel sampling a correction factor is proposed. This correction factor is applied to the patient specific dose factors calculated with the native voxel size of the PET/CT study.

  2. Designing patient-specific 3D printed craniofacial implants using a novel topology optimization method.

    Science.gov (United States)

    Sutradhar, Alok; Park, Jaejong; Carrau, Diana; Nguyen, Tam H; Miller, Michael J; Paulino, Glaucio H

    2016-07-01

    Large craniofacial defects require efficient bone replacements which should not only provide good aesthetics but also possess stable structural function. The proposed work uses a novel multiresolution topology optimization method to achieve the task. Using a compliance minimization objective, patient-specific bone replacement shapes can be designed for different clinical cases that ensure revival of efficient load transfer mechanisms in the mid-face. In this work, four clinical cases are introduced and their respective patient-specific designs are obtained using the proposed method. The optimized designs are then virtually inserted into the defect to visually inspect the viability of the design . Further, once the design is verified by the reconstructive surgeon, prototypes are fabricated using a 3D printer for validation. The robustness of the designs are mechanically tested by subjecting them to a physiological loading condition which mimics the masticatory activity. The full-field strain result through 3D image correlation and the finite element analysis implies that the solution can survive the maximum mastication of 120 lb. Also, the designs have the potential to restore the buttress system and provide the structural integrity. Using the topology optimization framework in designing the bone replacement shapes would deliver surgeons new alternatives for rather complicated mid-face reconstruction.

  3. Patient-specific computer modelling of coronary bifurcation stenting: the John Doe programme.

    Science.gov (United States)

    Mortier, Peter; Wentzel, Jolanda J; De Santis, Gianluca; Chiastra, Claudio; Migliavacca, Francesco; De Beule, Matthieu; Louvard, Yves; Dubini, Gabriele

    2015-01-01

    John Doe, an 81-year-old patient with a significant distal left main (LM) stenosis, was treated using a provisional stenting approach. As part of an European Bifurcation Club (EBC) project, the complete stenting procedure was repeated using computational modelling. First, a tailored three-dimensional (3D) reconstruction of the bifurcation anatomy was created by fusion of multislice computed tomography (CT) imaging and intravascular ultrasound. Second, finite element analysis was employed to deploy and post-dilate the stent virtually within the generated patient-specific anatomical bifurcation model. Finally, blood flow was modelled using computational fluid dynamics. This proof-of-concept study demonstrated the feasibility of such patient-specific simulations for bifurcation stenting and has provided unique insights into the bifurcation anatomy, the technical aspects of LM bifurcation stenting, and the positive impact of adequate post-dilatation on blood flow patterns. Potential clinical applications such as virtual trials and preoperative planning seem feasible but require a thorough clinical validation of the predictive power of these computer simulations.

  4. Comparison of Detailed and Simplified Models of Human Atrial Myocytes to Recapitulate Patient Specific Properties.

    Science.gov (United States)

    Lombardo, Daniel M; Fenton, Flavio H; Narayan, Sanjiv M; Rappel, Wouter-Jan

    2016-08-01

    Computer studies are often used to study mechanisms of cardiac arrhythmias, including atrial fibrillation (AF). A crucial component in these studies is the electrophysiological model that describes the membrane potential of myocytes. The models vary from detailed, describing numerous ion channels, to simplified, grouping ionic channels into a minimal set of variables. The parameters of these models, however, are determined across different experiments in varied species. Furthermore, a single set of parameters may not describe variations across patients, and models have rarely been shown to recapitulate critical features of AF in a given patient. In this study we develop physiologically accurate computational human atrial models by fitting parameters of a detailed and of a simplified model to clinical data for five patients undergoing ablation therapy. Parameters were simultaneously fitted to action potential (AP) morphology, action potential duration (APD) restitution and conduction velocity (CV) restitution curves in these patients. For both models, our fitting procedure generated parameter sets that accurately reproduced clinical data, but differed markedly from published sets and between patients, emphasizing the need for patient-specific adjustment. Both models produced two-dimensional spiral wave dynamics for that were similar for each patient. These results show that simplified, computationally efficient models are an attractive choice for simulations of human atrial electrophysiology in spatially extended domains. This study motivates the development and validation of patient-specific model-based mechanistic studies to target therapy. PMID:27494252

  5. Anesthesia and perioperative management of colorectal surgical patients - specific issues (part 2

    Directory of Open Access Journals (Sweden)

    Santosh Patel

    2012-01-01

    Full Text Available Colorectal surgery carries significant morbidity and mortality, which is associated with an enormous use of healthcare resources. Patients with pre-existing morbidities, and those undergoing emergency colorectal surgery due to complications such as perforation, obstruction, or ischemia / infarction are at an increased risk for adverse outcomes. Fluid therapy in emergency colorectal surgical patients can be challenging as hypovolemic and septic shock may coexist. Abdominal sepsis is a serious complication and may be diagnosed during pre-, intra-, or postoperative periods. Early suspicion and recognition of medical and / or surgical complications are essential. The critical care management of complicated colorectal surgical patients require collaborative and multidisciplinary efforts.

  6. Corneal Topographical Changes Flollowing Strabismus Surgery

    Institute of Scientific and Technical Information of China (English)

    MaiGH; WangZ

    1999-01-01

    Purpose:To study corneal topographical changes after strabismus surgery.Methods:Computer-aided corneal topography was used in 43 strabismus patients(45 eyes)one or two days prior to and six or seven ays after strabismus surgery.The spherical and cylindrical equivalents were calculated based on the simulated keratometry.Results:After the surgery,only the changes at 3mm in the inferior quadrant were statistically significant.The changes at 3mm in the rest quadrants and the changes at 7mm were no significant.Significant changes in spherical equivalent were found post-operatively.neither the horizontal nor the verical meridional equivalent showed significant changes after surgery.Conclusions:The results of corneal topographical changes following strabismus surgery in our preliminary study indicated the little effect of strabismus surgery on corneal curvature and corneal astigmatism.

  7. Tactile Aids

    Directory of Open Access Journals (Sweden)

    Mohtaramossadat Homayuni

    1996-04-01

    Full Text Available Tactile aids, which translate sound waves into vibrations that can be felt by the skin, have been used for decades by people with severe/profound hearing loss to enhance speech/language development and improve speechreading.The development of tactile aids dates from the efforts of Goults and his co-workers in the 1920s; Although The power supply was too voluminous and it was difficult to carry specially by children, it was too huge and heavy to be carried outside the laboratories and its application was restricted to the experimental usage. Nowadays great advances have been performed in producing this instrument and its numerous models is available in markets around the world.

  8. A fast and robust patient specific Finite Element mesh registration technique: application to 60 clinical cases

    CERN Document Server

    Bucki, Marek; Payan, Yohan; 10.1016/j.media.2010.02.003

    2010-01-01

    Finite Element mesh generation remains an important issue for patient specific biomechanical modeling. While some techniques make automatic mesh generation possible, in most cases, manual mesh generation is preferred for better control over the sub-domain representation, element type, layout and refinement that it provides. Yet, this option is time consuming and not suited for intraoperative situations where model generation and computation time is critical. To overcome this problem we propose a fast and automatic mesh generation technique based on the elastic registration of a generic mesh to the specific target organ in conjunction with element regularity and quality correction. This Mesh-Match-and-Repair (MMRep) approach combines control over the mesh structure along with fast and robust meshing capabilities, even in situations where only partial organ geometry is available. The technique was successfully tested on a database of 5 pre-operatively acquired complete femora CT scans, 5 femoral heads partially...

  9. Ionization chamber array for patient specific VMAT, Tomotherapy and IMRT QA

    Energy Technology Data Exchange (ETDEWEB)

    Stathakis, Sotiri, E-mail: Stathakis@uthscsa.ed [Department of Radiation Oncology, Cancer Therapy and Research Center at the University of Texas Health Science Center, San Antonio TX 78229 (United States)

    2010-11-01

    The evaluation between measured and calculated dose is essential in the patient specific quality assurance procedures for intensity modulated radiation therapy. The high complexity of volumetric arc radiotherapy, Tomotherpay and intensity modulated radiation therapy deliveries attributed to the dynamic and synchronization requirements of such techniques require new methods and potentially new tools for the quality assurance of such techniques. Studies evaluating the dosimetric performance of EDR2 film and a 2D ionization chamber array quality assurance device have been performed in our institution. Our results showed that differences between the detector systems are small. The respective gamma index histograms showed that when 3% dose difference and 3mm distance to agreement are used, more than 90% of the evaluated points were within the tolerance criteria

  10. Characterization of the transport topology in patient-specific abdominal aortic aneurysm models

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn C.

    2012-08-01

    Abdominal aortic aneurysm (AAA) is characterized by disturbed blood flow patterns that are hypothesized to contribute to disease progression. The transport topology in six patient-specific abdominal aortic aneurysms was studied. Velocity data were obtained by image-based computational fluid dynamics modeling, with magnetic resonance imaging providing the necessary simulation parameters. Finite-time Lyapunov exponent (FTLE) fields were computed from the velocity data, and used to identify Lagrangian coherent structures (LCS). The combination of FTLE fields and LCS was used to characterize topological flow features such as separation zones, vortex transport, mixing regions, and flow impingement. These measures offer a novel perspective into AAA flow. It was observed that all aneurysms exhibited coherent vortex formation at the proximal segment of the aneurysm. The evolution of the systolic vortex strongly influences the flow topology in the aneurysm. It was difficult to predict the vortex dynamics from the aneurysm morphology, motivating the application of image-based flow modeling.

  11. Ansys Fluent versus Sim Vascular for 4-D patient-specific computational hemodynamics in renal arteries

    Science.gov (United States)

    Mumbaraddi, Avinash; Yu, Huidan (Whitney); Sawchuk, Alan; Dalsing, Michael

    2015-11-01

    The objective of this clinical-need driven research is to investigate the effect of renal artery stenosis (RAS) on the blood flow and wall shear stress in renal arteries through 4-D patient-specific computational hemodynamics (PSCH) and search for possible critical RASs that significantly alter the pressure gradient across the stenosis by manually varying the size of RAS from 50% to 95%. The identification of the critical RAS is important to understand the contribution of RAS to the overall renal resistance thus appropriate clinical therapy can be determined in order to reduce the hypertension. Clinical CT angiographic data together with Doppler Ultra sound images of an anonymous patient are used serving as the required inputs of the PSCH. To validate the PSCH, we use both Ansys Fluent and Sim Vascular and compare velocity, pressure, and wall-shear stress under identical conditions. Renal Imaging Technology Development Program (RITDP) Grant.

  12. Development of a patient-specific dosimetry estimation system in nuclear medicine examination

    Energy Technology Data Exchange (ETDEWEB)

    Lin, H. H.; Dong, S. L.; Yang, H. J. [Dept. of Biomedical Engineering and Environmental Sciences, National Tsing-Hua Univ., Taiwan (China); Chen, S. [Dept. of Medical Imaging and Radiological Sciences, Kaohsiung Medical Univ., Taiwan (China); Shih, C. T. [Dept. of Biomedical Engineering and Environmental Sciences, National Tsing-Hua Univ., Taiwan (China); Chuang, K. S. [Inst. of Nuclear Engineering and Sciences, National Tsing-Hua Univ., Taiwan (China); Lin, C. H. [Dept. of Biomedical Engineering and Environmental Sciences, National Tsing-Hua Univ., Taiwan (China); Yao, W. J. [PET Center, National Cheng Kung Univ. Hospital, Taiwan (China); Jan, M. L. [Physics Div., Inst. of Nuclear Energy Research, Atomic Energy Council, Taiwan (China)

    2011-07-01

    The purpose of this study is to develop a patient-specific dosimetry estimation system in nuclear medicine examination using a SimSET-based Monte Carlo code. We added a dose deposition routine to store the deposited energy of the photons during their flights in SimSET and developed a user-friendly interface for reading PET and CT images. Dose calculated on ORNL phantom was used to validate the accuracy of this system. The S values for {sup 99m}Tc, {sup 18}F and {sup 131}I obtained by the system were compared to those from the MCNP4C code and OLINDA. The ratios of S values computed by this system to those obtained with OLINDA for various organs were ranged from 0.93 to 1.18, which are comparable to that obtained from MCNP4C code (0.94 to 1.20). The average ratios of S value were 0.99{+-}0.04, 1.03{+-}0.05, and 1.00{+-}0.07 for isotopes {sup 131}I, {sup 18}F, and {sup 99m}Tc, respectively. The simulation time of SimSET was two times faster than MCNP4C's for various isotopes. A 3D dose calculation was also performed on a patient data set with PET/CT examination using this system. Results from the patient data showed that the estimated S values using this system differed slightly from those of OLINDA for ORNL phantom. In conclusion, this system can generate patient-specific dose distribution and display the isodose curves on top of the anatomic structure through a friendly graphic user interface. It may also provide a useful tool to establish an appropriate dose-reduction strategy to patients in nuclear medicine environments. (authors)

  13. An automatic CFD-based flow diverter optimization principle for patient-specific intracranial aneurysms.

    Science.gov (United States)

    Janiga, Gábor; Daróczy, László; Berg, Philipp; Thévenin, Dominique; Skalej, Martin; Beuing, Oliver

    2015-11-01

    The optimal treatment of intracranial aneurysms using flow diverting devices is a fundamental issue for neuroradiologists as well as neurosurgeons. Due to highly irregular manifold aneurysm shapes and locations, the choice of the stent and the patient-specific deployment strategy can be a very difficult decision. To support the therapy planning, a new method is introduced that combines a three-dimensional CFD-based optimization with a realistic deployment of a virtual flow diverting stent for a given aneurysm. To demonstrate the feasibility of this method, it was applied to a patient-specific intracranial giant aneurysm that was successfully treated using a commercial flow diverter. Eight treatment scenarios with different local compressions were considered in a fully automated simulation loop. The impact on the corresponding blood flow behavior was evaluated qualitatively as well as quantitatively, and the optimal configuration for this specific case was identified. The virtual deployment of an uncompressed flow diverter reduced the inflow into the aneurysm by 24.4% compared to the untreated case. Depending on the positioning of the local stent compression below the ostium, blood flow reduction could vary between 27.3% and 33.4%. Therefore, a broad range of potential treatment outcomes was identified, illustrating the variability of a given flow diverter deployment in general. This method represents a proof of concept to automatically identify the optimal treatment for a patient in a virtual study under certain assumptions. Hence, it contributes to the improvement of virtual stenting for intracranial aneurysms and can support physicians during therapy planning in the future.

  14. The numerical analysis of non-Newtonian blood flow in human patient-specific left ventricle.

    Science.gov (United States)

    Doost, Siamak N; Zhong, Liang; Su, Boyang; Morsi, Yosry S

    2016-04-01

    Recently, various non-invasive tools such as the magnetic resonance image (MRI), ultrasound imaging (USI), computed tomography (CT), and the computational fluid dynamics (CFD) have been widely utilized to enhance our current understanding of the physiological parameters that affect the initiation and the progression of the cardiovascular diseases (CVDs) associated with heart failure (HF). In particular, the hemodynamics of left ventricle (LV) has attracted the attention of the researchers due to its significant role in the heart functionality. In this study, CFD owing its capability of predicting detailed flow field was adopted to model the blood flow in images-based patient-specific LV over cardiac cycle. In most published studies, the blood is modeled as Newtonian that is not entirely accurate as the blood viscosity varies with the shear rate in non-linear manner. In this paper, we studied the effect of Newtonian assumption on the degree of accuracy of intraventricular hemodynamics. In doing so, various non-Newtonian models and Newtonian model are used in the analysis of the intraventricular flow and the viscosity of the blood. Initially, we used the cardiac MRI images to reconstruct the time-resolved geometry of the patient-specific LV. After the unstructured mesh generation, the simulations were conducted in the CFD commercial solver FLUENT to analyze the intraventricular hemodynamic parameters. The findings indicate that the Newtonian assumption cannot adequately simulate the flow dynamic within the LV over the cardiac cycle, which can be attributed to the pulsatile and recirculation nature of the flow and the low blood shear rate. PMID:26849955

  15. Principal direction of inertia for 3D trajectories from patient-specific TMJ movement.

    Science.gov (United States)

    Kim, Dae-Seung; Choi, Soon-Chul; Lee, Sam-Sun; Heo, Min-Suk; Huh, Kyung-Hoe; Hwang, Soon-Jung; Kim, Seong-Ha; Yi, Won-Jin

    2013-03-01

    Accurate simulation and evaluation of mandibular movement is fundamental for the analysis of functional changes and effects of the mandible and maxilla before and after surgical treatments. We applied principal axes of inertia to the three-dimensional (3D) trajectories generated by patient-specific simulations of TMJ movements for the functional evaluations of mandible movement. Three-dimensional movements of the mandible and the maxilla were tracked based on a patient-specific splint and an optical tracking system. The dental occlusion recorded on the sprint provided synchronization for initial movement in the tracking and the simulation phases. The translation and rotation recorded during movement tracking was applied sequentially to the mandibular model in relation to a fixed maxilla model. The sequential 3D positions of selected landmarks on the mandible were calculated based on the reference coordinate system. The landmarks selected for analysis were bilateral condyles and pogonion points. The moment of inertia tensor was calculated with respect to the 3D trajectory points. Using the unit vectors along the principal axes derived from the tensor matrix, α, β and γ rotations around z-, y- and x-axes were determined to represent the principal directions as principal rotations respectively. The γ direction showed the higher standard deviation, variation of directions, than other directions at all the landmarks. The mandible movement has larger kinematic redundancy in the γ direction than α and β during mouth opening and closing. Principal directions of inertia would be applied to analyzing the changes in angular motion of trajectories introduced by mandibular shape changes from surgical treatments and also to the analysis of the influence of skeletal deformities on mandibular movement asymmetry. PMID:23321156

  16. EFFECTS OF PARENT ARTERY SEGMENTATION AND ANEURISMALWALL ELASTICITY ON PATIENT-SPECIFIC HEMODYNAMIC SIMULATIONS

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-liang; DING Guang-hong; YANG Xin-jian; LI Hai-yun

    2011-01-01

    It is well known that hemodynamics and wall tension play an important role in the formation,growth and rupture of aneurysms.In the present study,the authors investigated the influence of parent artery segmentation and aneurismal-wall elasticity on patient-specific hemodynamic simulations with two patient-specific eases of cerebral aneurysms.Realistic models of the aneurysms were constructed from 3-D angiography images and blood flow dynamics was studied under physiologically representative waveform of inflow.For each aneurysm three computational models were constructed:Model 1 with more extensive upstream parent artery with the rigid arterial and aneurismal wall,Model 2 with the partial upstream parent artery with the elastic arterial and aneurismal wall,Model 3 with more extensive upstream parent artery with the rigid wall for arterial wall far from the aneurysm and the elastic wall for arterial wall near the aneurysm.The results show that Model 1 could predict complex intra-aneurismal flow patterns and wall shear stress distribution in the aneurysm,but is unable to give aneurismal wall deformation and tension,Model 2 demonstrates aneurismal wall deformation and tension,but fails to properly model inflow pattern contributed by the upstream parent artery,resulting in local misunderstanding Wall Shear Stress (WSS) distribution,Model 3 can overcome limitations of the former two models,and give an overall and accurate analysis on intra-aneurismal flow patterns,wall shear stress distribution,aneurismal-wall deformation and tension.Therefore we suggest that the proper length of extensive upstream parent artery and aneuri-smal-wall elasticity should be considered carefully in establishing computational model to predict the intra-aneurismal hemodynamic and wall tension.

  17. SU-E-T-603: PBS Prostate Plan Robustness: A Tool for Patient Specific Setup Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Tang, S; Song, L; Chen, C; Chang, C; Chon, B; Tsai, H; Soffen, E; Cahlon, O; Mah, D [Procure Proton Therapy Center, Somerset, NJ (United States)

    2015-06-15

    Purpose: Fiducial markers are commonly used for setup of prostate patients using orthogonal radiographs. After aligned with the markers, the displacement of the bony anatomy relative to the planned DRR can be up to 10 mm. Such offset can potentially have significant dosimetric effects because it changes the radiological path length of protons in differing amounts of bone. It is imperative to develop a method to evaluate its impact on target coverage and hence establish patient specific setup tolerance for prostate proton PBS treatment. Methods: Prostate patients were planned in RayStation according to the PCG protocol with bi-lateral beams. The primary planning objectives are: (1) 100% of CTV receives full prescription dose; (2) 98% of the prescription dose covers at least 98% of the PTV; (3) OARs meet criteria per protocol. For each patient 108 dose perturbations were automatically generated using an in-house script, which considered the isocenter shifting in S-I and A-P directions (up to ±15 mm with an interval of 6mm) as well as the range uncertainty (±3.5%). The target coverage was evaluated on the contour shifted along with prostate to mimic the daily treatment. Results: The minimum CTV coverage as a function of offsets in S-I and A-P directions is presented in a 2D contour map. The offsets along A-P direction generally have greater impact than along S-I direction. Both the CTV D98%>98% or CTV V98%>98% are achievable for most patients if the offset is <10 mm in either direction despite of range uncertainties. Conclusion: We developed a method to evaluate the plan robustness for proton PBS prostate treatment. It can provide patient specific setup tolerance of bony structure offset. For our current planning approach, a 1 cm displacement is acceptable. This approach can be generalized to other target structures that move relative to bony anatomy.

  18. Challenges and limitations of patient-specific vascular phantom fabrication using 3D Polyjet printing

    Science.gov (United States)

    Ionita, Ciprian N.; Mokin, Maxim; Varble, Nicole; Bednarek, Daniel R.; Xiang, Jianping; Snyder, Kenneth V.; Siddiqui, Adnan H.; Levy, Elad I.; Meng, Hui; Rudin, Stephen

    2014-03-01

    Additive manufacturing (3D printing) technology offers a great opportunity towards development of patient-specific vascular anatomic models, for medical device testing and physiological condition evaluation. However, the development process is not yet well established and there are various limitations depending on the printing materials, the technology and the printer resolution. Patient-specific neuro-vascular anatomy was acquired from computed tomography angiography and rotational digital subtraction angiography (DSA). The volumes were imported into a Vitrea 3D workstation (Vital Images Inc.) and the vascular lumen of various vessels and pathologies were segmented using a "marching cubes" algorithm. The results were exported as Stereo Lithographic (STL) files and were further processed by smoothing, trimming, and wall extrusion (to add a custom wall to the model). The models were printed using a Polyjet printer, Eden 260V (Objet-Stratasys). To verify the phantom geometry accuracy, the phantom was reimaged using rotational DSA, and the new data was compared with the initial patient data. The most challenging part of the phantom manufacturing was removal of support material. This aspect could be a serious hurdle in building very tortuous phantoms or small vessels. The accuracy of the printed models was very good: distance analysis showed average differences of 120 μm between the patient and the phantom reconstructed volume dimensions. Most errors were due to residual support material left in the lumen of the phantom. Despite the post-printing challenges experienced during the support cleaning, this technology could be a tremendous benefit to medical research such as in device development and testing.

  19. Towards Effective and Efficient Patient-Specific Quality Assurance for Spot Scanning Proton Therapy

    International Nuclear Information System (INIS)

    An intensity-modulated proton therapy (IMPT) patient-specific quality assurance (PSQA) program based on measurement alone can be very time consuming due to the highly modulated dose distributions of IMPT fields. Incorporating independent dose calculation and treatment log file analysis could reduce the time required for measurements. In this article, we summarize our effort to develop an efficient and effective PSQA program that consists of three components: measurements, independent dose calculation, and analysis of patient-specific treatment delivery log files. Measurements included two-dimensional (2D) measurements using an ionization chamber array detector for each field delivered at the planned gantry angles with the electronic medical record (EMR) system in the QA mode and the accelerator control system (ACS) in the treatment mode, and additional measurements at depths for each field with the ACS in physics mode and without the EMR system. Dose distributions for each field in a water phantom were calculated independently using a recently developed in-house pencil beam algorithm and compared with those obtained using the treatment planning system (TPS). The treatment log file for each field was analyzed in terms of deviations in delivered spot positions from their planned positions using various statistical methods. Using this improved PSQA program, we were able to verify the integrity of the data transfer from the TPS to the EMR to the ACS, the dose calculation of the TPS, and the treatment delivery, including the dose delivered and spot positions. On the basis of this experience, we estimate that the in-room measurement time required for each complex IMPT case (e.g., a patient receiving bilateral IMPT for head and neck cancer) is less than 1 h using the improved PSQA program. Our experience demonstrates that it is possible to develop an efficient and effective PSQA program for IMPT with the equipment and resources available in the clinic

  20. Dose reconstruction for real-time patient-specific dose estimation in CT

    Energy Technology Data Exchange (ETDEWEB)

    De Man, Bruno, E-mail: deman@ge.com; Yin, Zhye [Image Reconstruction Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Wu, Mingye [X-ray and CT Laboratory, GE Global Research, Shanghai 201203 (China); FitzGerald, Paul [Radiation Systems Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Kalra, Mannudeep [Divisions of Thoracic and Cardiac Imaging, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

    2015-05-15

    Purpose: Many recent computed tomography (CT) dose reduction approaches belong to one of three categories: statistical reconstruction algorithms, efficient x-ray detectors, and optimized CT acquisition schemes with precise control over the x-ray distribution. The latter category could greatly benefit from fast and accurate methods for dose estimation, which would enable real-time patient-specific protocol optimization. Methods: The authors present a new method for volumetrically reconstructing absorbed dose on a per-voxel basis, directly from the actual CT images. The authors’ specific implementation combines a distance-driven pencil-beam approach to model the first-order x-ray interactions with a set of Gaussian convolution kernels to model the higher-order x-ray interactions. The authors performed a number of 3D simulation experiments comparing the proposed method to a Monte Carlo based ground truth. Results: The authors’ results indicate that the proposed approach offers a good trade-off between accuracy and computational efficiency. The images show a good qualitative correspondence to Monte Carlo estimates. Preliminary quantitative results show errors below 10%, except in bone regions, where the authors see a bigger model mismatch. The computational complexity is similar to that of a low-resolution filtered-backprojection algorithm. Conclusions: The authors present a method for analytic dose reconstruction in CT, similar to the techniques used in radiation therapy planning with megavoltage energies. Future work will include refinements of the proposed method to improve the accuracy as well as a more extensive validation study. The proposed method is not intended to replace methods that track individual x-ray photons, but the authors expect that it may prove useful in applications where real-time patient-specific dose estimation is required.

  1. Towards Effective and Efficient Patient-Specific Quality Assurance for Spot Scanning Proton Therapy

    Directory of Open Access Journals (Sweden)

    X. Ronald. Zhu

    2015-04-01

    Full Text Available An intensity-modulated proton therapy (IMPT patient-specific quality assurance (PSQA program based on measurement alone can be very time consuming due to the highly modulated dose distributions of IMPT fields. Incorporating independent dose calculation and treatment log file analysis could reduce the time required for measurements. In this article, we summarize our effort to develop an efficient and effective PSQA program that consists of three components: measurements, independent dose calculation, and analysis of patient-specific treatment delivery log files. Measurements included two-dimensional (2D measurements using an ionization chamber array detector for each field delivered at the planned gantry angles with the electronic medical record (EMR system in the QA mode and the accelerator control system (ACS in the treatment mode, and additional measurements at depths for each field with the ACS in physics mode and without the EMR system. Dose distributions for each field in a water phantom were calculated independently using a recently developed in-house pencil beam algorithm and compared with those obtained using the treatment planning system (TPS. The treatment log file for each field was analyzed in terms of deviations in delivered spot positions from their planned positions using various statistical methods. Using this improved PSQA program, we were able to verify the integrity of the data transfer from the TPS to the EMR to the ACS, the dose calculation of the TPS, and the treatment delivery, including the dose delivered and spot positions. On the basis of this experience, we estimate that the in-room measurement time required for each complex IMPT case (e.g., a patient receiving bilateral IMPT for head and neck cancer is less than 1 h using the improved PSQA program. Our experience demonstrates that it is possible to develop an efficient and effective PSQA program for IMPT with the equipment and resources available in the clinic.

  2. Are patient-specific joint and inertial parameters necessary for accurate inverse dynamics analyses of gait?

    Science.gov (United States)

    Reinbolt, Jeffrey A; Haftka, Raphael T; Chmielewski, Terese L; Fregly, Benjamin J

    2007-05-01

    Variations in joint parameter (JP) values (axis positions and orientations in body segments) and inertial parameter (IP) values (segment masses, mass centers, and moments of inertia) as well as kinematic noise alter the results of inverse dynamics analyses of gait. Three-dimensional linkage models with joint constraints have been proposed as one way to minimize the effects of noisy kinematic data. Such models can also be used to perform gait optimizations to predict post-treatment function given pre-treatment gait data. This study evaluates whether accurate patient-specific JP and IP values are needed in three-dimensional linkage models to produce accurate inverse dynamics results for gait. The study was performed in two stages. First, we used optimization analyses to evaluate whether patient-specific JP and IP values can be calibrated accurately from noisy kinematic data, and second, we used Monte Carlo analyses to evaluate how errors in JP and IP values affect inverse dynamics calculations. Both stages were performed using a dynamic, 27 degrees-of-freedom, full-body linkage model and synthetic (i.e., computer generated) gait data corresponding to a nominal experimental gait motion. In general, JP but not IP values could be found accurately from noisy kinematic data. Root-mean-square (RMS) errors were 3 degrees and 4 mm for JP values and 1 kg, 22 mm, and 74 500 kg * mm2 for IP values. Furthermore, errors in JP but not IP values had a significant effect on calculated lower-extremity inverse dynamics joint torques. The worst RMS torque error averaged 4% bodyweight * height (BW * H) due to JP variations but less than 0.25% (BW * H) due to IP variations. These results suggest that inverse dynamics analyses of gait utilizing linkage models with joint constraints should calibrate the model's JP values to obtain accurate joint torques.

  3. Towards Effective and Efficient Patient-Specific Quality Assurance for Spot Scanning Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X. Ronald., E-mail: xrzhu@mdanderson.org; Li, Yupeng; Mackin, Dennis; Li, Heng; Poenisch, Falk [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030 (United States); Lee, Andrew K.; Mahajan, Anita; Frank, Steven J. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030 (United States); Gillin, Michael T.; Sahoo, Narayan; Zhang, Xiaodong [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030 (United States)

    2015-04-13

    An intensity-modulated proton therapy (IMPT) patient-specific quality assurance (PSQA) program based on measurement alone can be very time consuming due to the highly modulated dose distributions of IMPT fields. Incorporating independent dose calculation and treatment log file analysis could reduce the time required for measurements. In this article, we summarize our effort to develop an efficient and effective PSQA program that consists of three components: measurements, independent dose calculation, and analysis of patient-specific treatment delivery log files. Measurements included two-dimensional (2D) measurements using an ionization chamber array detector for each field delivered at the planned gantry angles with the electronic medical record (EMR) system in the QA mode and the accelerator control system (ACS) in the treatment mode, and additional measurements at depths for each field with the ACS in physics mode and without the EMR system. Dose distributions for each field in a water phantom were calculated independently using a recently developed in-house pencil beam algorithm and compared with those obtained using the treatment planning system (TPS). The treatment log file for each field was analyzed in terms of deviations in delivered spot positions from their planned positions using various statistical methods. Using this improved PSQA program, we were able to verify the integrity of the data transfer from the TPS to the EMR to the ACS, the dose calculation of the TPS, and the treatment delivery, including the dose delivered and spot positions. On the basis of this experience, we estimate that the in-room measurement time required for each complex IMPT case (e.g., a patient receiving bilateral IMPT for head and neck cancer) is less than 1 h using the improved PSQA program. Our experience demonstrates that it is possible to develop an efficient and effective PSQA program for IMPT with the equipment and resources available in the clinic.

  4. The influence of boundary conditions on wall shear stress distribution in patients specific coronary trees.

    Science.gov (United States)

    van der Giessen, Alina G; Groen, Harald C; Doriot, Pierre-André; de Feyter, Pim J; van der Steen, Antonius F W; van de Vosse, Frans N; Wentzel, Jolanda J; Gijsen, Frank J H

    2011-04-01

    Patient specific geometrical data on human coronary arteries can be reliably obtained multislice computer tomography (MSCT) imaging. MSCT cannot provide hemodynamic variables, and the outflow through the side branches must be estimated. The impact of two different models to determine flow through the side branches on the wall shear stress (WSS) distribution in patient specific geometries is evaluated. Murray's law predicts that the flow ratio through the side branches scales with the ratio of the diameter of the side branches to the third power. The empirical model is based on flow measurements performed by Doriot et al. (2000) in angiographically normal coronary arteries. The fit based on these measurements showed that the flow ratio through the side branches can best be described with a power of 2.27. The experimental data imply that Murray's law underestimates the flow through the side branches. We applied the two models to study the WSS distribution in 6 coronary artery trees. Under steady flow conditions, the average WSS between the side branches differed significantly for the two models: the average WSS was 8% higher for Murray's law and the relative difference ranged from -5% to +27%. These differences scale with the difference in flow rate. Near the bifurcations, the differences in WSS were more pronounced: the size of the low WSS regions was significantly larger when applying the empirical model (13%), ranging from -12% to +68%. Predicting outflow based on Murray's law underestimates the flow through the side branches. Especially near side branches, the regions where atherosclerotic plaques preferentially develop, the differences are significant and application of Murray's law underestimates the size of the low WSS region.

  5. Modeling the consequences of tongue surgery on tongue mobility

    CERN Document Server

    Buchaillard, Stéphanie; Perrier, Pascal; Payan, Yohan

    2007-01-01

    This paper presents the current achievements of a long term project aiming at predicting and assessing the impact of tongue and mouth floor surgery on tongue mobility. The ultimate objective of this project is the design of a software with which surgeons should be able (1) to design a 3D biomechanical model of the tongue and of the mouth floor that matches the anatomical characteristics of each patient specific oral cavity, (2) to simulate the anatomical changes induced by the surgery and the possible reconstruction, and (3) to quantitatively predict and assess the consequences of these anatomical changes on tongue mobility and speech production after surgery.

  6. Computer assisted radiology and surgery. CARS 2010

    International Nuclear Information System (INIS)

    The conference proceedings include contributions to the following topics: (1) CARS Clinical Day: minimally invasive spiral surgery, interventional radiology; (2) CARS - computer assisted radiology and surgery: ophthalmology, stimulation methods, new approaches to diagnosis and therapy; (3) Computer assisted radiology 24th International congress and exhibition: computer tomography and magnetic resonance, digital angiographic imaging, digital radiography, ultrasound, computer assisted radiation therapy, medical workstations, image processing and display; (4) 14th Annual conference of the International Society for computer aided surgery; ENT-CMF head and neck surgery computer-assisted neurosurgery, cardiovascular surgery, image guided liver surgery, abdominal and laparoscopic surgery, computer-assisted orthopedic surgery, image processing and visualization, surgical robotics and instrumentation, surgical modeling, simulation and education; (5) 28th International EuroPACS meeting: image distribution and integration strategies, planning and evaluation, telemedicine and standards, workflow and data flow in radiology; (6) 11th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, management and assessment of OR systems and integration; (7) 12th International workshop on computer-aided diagnosis: special session on breast CAD, special session on thoracic CAD, special session on abdominal brain, lumbar spine CAD; (8) 16th computed Maxillofacial imaging congress: computed maxillofacial imaging in dental implantology, orthodontics and dentofacial orthopedics; approaches to 3D maxillofacial imaging; surgical navigation; (9) 2nd EuroNOTES/CARS workshop on NOTES: an interdisciplinary challenge; (10) 2nd EPMA/CARS workshop on personalized medicine and ICT.; (11)poster sessions.

  7. Computer assisted radiology and surgery. CARS 2010

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2010-06-15

    The conference proceedings include contributions to the following topics: (1) CARS Clinical Day: minimally invasive spiral surgery, interventional radiology; (2) CARS - computer assisted radiology and surgery: ophthalmology, stimulation methods, new approaches to diagnosis and therapy; (3) Computer assisted radiology 24th International congress and exhibition: computer tomography and magnetic resonance, digital angiographic imaging, digital radiography, ultrasound, computer assisted radiation therapy, medical workstations, image processing and display; (4) 14th Annual conference of the International Society for computer aided surgery; ENT-CMF head and neck surgery computer-assisted neurosurgery, cardiovascular surgery, image guided liver surgery, abdominal and laparoscopic surgery, computer-assisted orthopedic surgery, image processing and visualization, surgical robotics and instrumentation, surgical modeling, simulation and education; (5) 28th International EuroPACS meeting: image distribution and integration strategies, planning and evaluation, telemedicine and standards, workflow and data flow in radiology; (6) 11th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, management and assessment of OR systems and integration; (7) 12th International workshop on computer-aided diagnosis: special session on breast CAD, special session on thoracic CAD, special session on abdominal brain, lumbar spine CAD; (8) 16th computed Maxillofacial imaging congress: computed maxillofacial imaging in dental implantology, orthodontics and dentofacial orthopedics; approaches to 3D maxillofacial imaging; surgical navigation; (9) 2nd EuroNOTES/CARS workshop on NOTES: an interdisciplinary challenge; (10) 2nd EPMA/CARS workshop on personalized medicine and ICT.; (11)poster sessions.

  8. Carotid artery surgery

    Science.gov (United States)

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  9. Neurological Complications of AIDS

    Science.gov (United States)

    ... Diversity Find People About NINDS Neurological Complications of AIDS Fact Sheet Feature Federal domestic HIV/AIDS information ... Where can I get more information? What is AIDS? AIDS (acquired immune deficiency syndrome) is a condition ...

  10. Emergency surgery

    DEFF Research Database (Denmark)

    Stoneham, M; Murray, D; Foss, N

    2014-01-01

    undertaken on elderly patients with limited physiological reserve. National audits have reported variations in care quality, data that are increasingly being used to drive quality improvement through professional guidance. Given that the number of elderly patients presenting for emergency surgery is likely...

  11. Cosmetic surgery.

    OpenAIRE

    1989-01-01

    The psychotherapeutic nature of cosmetic surgery is emphasised by outlining the range of symptoms from which patients suffer and by explaining the sequence of psychological reactions which cause them. The principles which govern the selection of patients are defined. A brief account of each of the main cosmetic operations is given together with notes on their limitations and risks.

  12. Choosing surgery

    DEFF Research Database (Denmark)

    Thorstensson, Carina; Lohmander, L; Frobell, Richard;

    2009-01-01

    ABSTRACT: BACKGROUND: The objective was to understand patients' views of treatment after acute anterior cruciate ligament (ACL) injury, and their reasons for deciding to request surgery despite consenting to participate in a randomised controlled trial (to 'cross-over'). METHODS: Thirty-four in...

  13. AIDS Epidemiyolojisi

    OpenAIRE

    SÜNTER, A.T.; PEKŞEN, Y.

    2010-01-01

    AIDS was first defined in the United States in 1981. It spreads to nearly all the countries of the world with a great speed and can infect everbody without any differantiation. The infection results in death and there is no cure or vaccine for it, yet. To data given to World Health Organization until July-1994, it is estimated that there are about 1 million patients and about 22 millions HIV positive persons In the world. Sixty percent of HIV positive persons are men and 40% are women. The di...

  14. Advances in Weight Loss Surgery: The Fully Robotic Gastric Bypass

    Medline Plus

    Full Text Available ... we have an added dimension, and the depth perception is incredible and just aids the surgery a ... have to be standing for long periods of time. And the ergonomics, just the manipulation of the ...

  15. [Tumor surgery].

    Science.gov (United States)

    Hausamen, J E

    2000-05-01

    Surgery is still the primary therapeutic approach in treatment of tumors in the head and neck area, dating back to the early nineteenth century. More than 150 years ago, hemimaxillectomies and mandibular resections as well as hemiglossectomies were already performed by leading surgeons. The block principle we are now following dates back to Crile, who also established the principle of cervical lymph node dissection. Ablative oncologic surgery has always been closely linked with plastic and reconstructive surgery, rendering radical surgical interventions possible without disfiguring patients. The development of facial reconstructive surgery proceeded in stages, in the first instance as secondary reconstruction using tube pedicled flaps. The change to the concept of primary reconstruction occurred via arterialized skin flaps and myocutaneous flaps to the widely accepted and performed free tissue transfer. Free bone grafting, inaugurated earlier and still representing the majority of bone grafting, has been supplemented for certain reconstructive purposes by free vascularized bone transfer from various donor sites. Although the five-year-survival rate of carcinoma of the oral cavity has remained unchanged in the past 30 years, distinctive improvements in tumor surgery can be recorded. This is primarily based on improved diagnostics such as modern imaging techniques and the refinement of surgical techniques. The DOSAK has worked out distinctive guidelines for effective ablative oncologic surgery. Surgical approaches offering wide exposure and carrying low morbidity play a decisive role in radical resections. For this reason, midfacial degloving offers an essential improvement for the resection of midface tumors, especially from an aesthetic point of view. Tumors situated deep behind the viscerocranium at the skull base can be clearly exposed either through a lateral approach following a temporary osteotomy of the mandibular ramus or a transmandibular, transmaxillar, or

  16. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... more. Dental and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the ... more. Dental and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the ...

  17. LASIK - Laser Eye Surgery

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ...

  18. Alternative Refractive Surgery Procedures

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ...

  19. What Is Refractive Surgery?

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ...

  20. American Board of Surgery

    Science.gov (United States)

    ... Exam Results Results of our fall exams in vascular surgery, pediatric surgery, surgical critical care and surgical oncology ... Feedback Joint Pathway - General & Thoracic Surgery Specialty Definition Vascular Surgery Training Pathways Related Policies Credit for Foreign Medical ...

  1. Facial Cosmetic Surgery

    Science.gov (United States)

    ... and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the soft tissues ... and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the soft tissues ...

  2. Dental Implant Surgery

    Science.gov (United States)

    ... and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the soft tissues ... and Soft Tissue Surgery Dental and Soft Tissue Surgery Oral and facial surgeons surgically treat the soft tissues ...

  3. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... to find out more. Facial Cosmetic Surgery Facial Cosmetic Surgery Extensive education and training in surgical procedures involving ... to find out more. Facial Cosmetic Surgery Facial Cosmetic Surgery Extensive education and training in surgical procedures involving ...

  4. Surgery for Breast Cancer

    Science.gov (United States)

    ... Next Topic Breast-conserving surgery (lumpectomy) Surgery for breast cancer Most women with breast cancer have some type ... Relieve symptoms of advanced cancer Surgery to remove breast cancer There are two main types of surgery to ...

  5. Scoliosis surgery - child

    Science.gov (United States)

    Spinal curvature surgery - child; Kyphoscoliosis surgery - child; Video-assisted thoracoscopic surgery - child; VATS - child ... Before surgery, your child will receive general anesthesia. This will make your child unconscious and unable to feel pain ...

  6. Heart bypass surgery

    Science.gov (United States)

    Off-pump coronary artery bypass; OPCAB; Beating heart surgery; Bypass surgery - heart; CABG; Coronary artery bypass graft; Coronary artery bypass surgery; Coronary bypass surgery; Coronary artery disease - CABG; CAD - CABG; Angina - ...

  7. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... to find out more. Facial Cosmetic Surgery Facial Cosmetic Surgery Extensive education and training in surgical procedures ... to find out more. Facial Cosmetic Surgery Facial Cosmetic Surgery Extensive education and training in surgical procedures ...

  8. Patient-specific CT dose determination from CT images using Monte Carlo simulations

    Science.gov (United States)

    Liang, Qing

    Radiation dose from computed tomography (CT) has become a public concern with the increasing application of CT as a diagnostic modality, which has generated a demand for patient-specific CT dose determinations. This thesis work aims to provide a clinically applicable Monte-Carlo-based CT dose calculation tool based on patient CT images. The source spectrum was simulated based on half-value layer measurements. Analytical calculations along with the measured flux distribution were used to estimate the bowtie-filter geometry. Relative source output at different points in a cylindrical phantom was measured and compared with Monte Carlo simulations to verify the determined spectrum and bowtie-filter geometry. Sensitivity tests were designed with four spectra with the same kVp and different half-value layers, and showed that the relative output at different locations in a phantom is sensitive to different beam qualities. An mAs-to-dose conversion factor was determined with in-air measurements using an Exradin A1SL ionization chamber. Longitudinal dose profiles were measured with thermoluminescent dosimeters (TLDs) and compared with the Monte-Carlo-simulated dose profiles to verify the mAs-to-dose conversion factor. Using only the CT images to perform Monte Carlo simulations would cause dose underestimation due to the lack of a scatter region. This scenario was demonstrated with a cylindrical phantom study. Four different image extrapolation methods from the existing CT images and the Scout images were proposed. The results show that performing image extrapolation beyond the scan region improves the dose calculation accuracy under both step-shoot scan mode and helical scan mode. Two clinical studies were designed and comparisons were performed between the current CT dose metrics and the Monte-Carlo-based organ dose determination techniques proposed in this work. The results showed that the current CT dosimetry failed to show dose differences between patients with the same

  9. Patient-specific Monte Carlo dose calculations for 103Pd breast brachytherapy

    Science.gov (United States)

    Miksys, N.; Cygler, J. E.; Caudrelier, J. M.; Thomson, R. M.

    2016-04-01

    This work retrospectively investigates patient-specific Monte Carlo (MC) dose calculations for 103Pd permanent implant breast brachytherapy, exploring various necessary assumptions for deriving virtual patient models: post-implant CT image metallic artifact reduction (MAR), tissue assignment schemes (TAS), and elemental tissue compositions. Three MAR methods (thresholding, 3D median filter, virtual sinogram) are applied to CT images; resulting images are compared to each other and to uncorrected images. Virtual patient models are then derived by application of different TAS ranging from TG-186 basic recommendations (mixed adipose and gland tissue at uniform literature-derived density) to detailed schemes (segmented adipose and gland with CT-derived densities). For detailed schemes, alternate mass density segmentation thresholds between adipose and gland are considered. Several literature-derived elemental compositions for adipose, gland and skin are compared. MC models derived from uncorrected CT images can yield large errors in dose calculations especially when used with detailed TAS. Differences in MAR method result in large differences in local doses when variations in CT number cause differences in tissue assignment. Between different MAR models (same TAS), PTV {{D}90} and skin {{D}1~\\text{c{{\\text{m}}3}}} each vary by up to 6%. Basic TAS (mixed adipose/gland tissue) generally yield higher dose metrics than detailed segmented schemes: PTV {{D}90} and skin {{D}1~\\text{c{{\\text{m}}3}}} are higher by up to 13% and 9% respectively. Employing alternate adipose, gland and skin elemental compositions can cause variations in PTV {{D}90} of up to 11% and skin {{D}1~\\text{c{{\\text{m}}3}}} of up to 30%. Overall, AAPM TG-43 overestimates dose to the PTV ({{D}90} on average 10% and up to 27%) and underestimates dose to the skin ({{D}1~\\text{c{{\\text{m}}3}}} on average 29% and up to 48%) compared to the various MC models derived using the post-MAR CT images studied

  10. Impact of Radioimmunoguided Surgery.

    Science.gov (United States)

    La Valle, G J; Chevinsky, A; Martin, E W

    1991-01-01

    Radioimmunoguided surgery (RIGS) is a technique employed to locate tumor deposits with the aid of intravenously injected, tumor-specific, radiolabeled monoclonal antibodies and a small gamma detecting device. The gamma detecting probe (GDP) is a small, portable unit which has the capacity to be used intraoperatively to survey the entire peritoneal surface for increased radioactivity indicative of targeted tumor tissue during abdominal exploration for colorectal cancer. Trials in humans have demonstrated the ability of this system to locate clinically nonpalpable tumor deposits in patients undergoing carcinoembryonic antigen second-look laparotomies. This feature may be of value in improving the definition of tumor location and extent as well as allowing a more thorough resection of tumor-bearing tissue to be performed and hopefully improving overall patient survival.

  11. Gene correction in patient-specific iPSCs for therapy development and disease modeling.

    Science.gov (United States)

    Jang, Yoon-Young; Ye, Zhaohui

    2016-09-01

    The discovery that mature cells can be reprogrammed to become pluripotent and the development of engineered endonucleases for enhancing genome editing are two of the most exciting and impactful technology advances in modern medicine and science. Human pluripotent stem cells have the potential to establish new model systems for studying human developmental biology and disease mechanisms. Gene correction in patient-specific iPSCs can also provide a novel source for autologous cell therapy. Although historically challenging, precise genome editing in human iPSCs is becoming more feasible with the development of new genome-editing tools, including ZFNs, TALENs, and CRISPR. iPSCs derived from patients of a variety of diseases have been edited to correct disease-associated mutations and to generate isogenic cell lines. After directed differentiation, many of the corrected iPSCs showed restored functionality and demonstrated their potential in cell replacement therapy. Genome-wide analyses of gene-corrected iPSCs have collectively demonstrated a high fidelity of the engineered endonucleases. Remaining challenges in clinical translation of these technologies include maintaining genome integrity of the iPSC clones and the differentiated cells. Given the rapid advances in genome-editing technologies, gene correction is no longer the bottleneck in developing iPSC-based gene and cell therapies; generating functional and transplantable cell types from iPSCs remains the biggest challenge needing to be addressed by the research field. PMID:27256364

  12. Patient specific fluid-structure ventricular modelling for integrated cardiac care.

    Science.gov (United States)

    de Vecchi, A; Nordsletten, D A; Razavi, R; Greil, G; Smith, N P

    2013-11-01

    Cardiac diseases represent one of the primary causes of mortality and result in a substantial decrease in quality of life. Optimal surgical planning and long-term treatment are crucial for a successful and cost-effective patient care. Recently developed state-of-the-art imaging techniques supply a wealth of detailed data to support diagnosis. This provides the foundations for a novel approach to clinical planning based on personalisation, which can lead to more tailored treatment plans when compared to strategies based on standard population metrics. The goal of this study is to develop and apply a methodology for creating personalised ventricular models of blood and tissue mechanics to assess patient-specific metrics. Fluid-structure interaction simulations are performed to analyse the diastolic function in hypoplastic left heart patients, who underwent the first stage of a three-step surgical palliation and whose condition must be accurately evaluated to plan further intervention. The kinetic energy changes generated by the blood propagation in early diastole are found to reflect the intraventricular pressure gradient, giving indications on the filling efficiency. This suggests good agreement between the 3D model and the Euler equation, which provides a simplified relationship between pressure and kinetic energy and could, therefore, be applied in the clinical context. PMID:23340962

  13. Fast Monte Carlo Simulation for Patient-specific CT/CBCT Imaging Dose Calculation

    CERN Document Server

    Jia, Xun; Gu, Xuejun; Jiang, Steve B

    2011-01-01

    Recently, X-ray imaging dose from computed tomography (CT) or cone beam CT (CBCT) scans has become a serious concern. Patient-specific imaging dose calculation has been proposed for the purpose of dose management. While Monte Carlo (MC) dose calculation can be quite accurate for this purpose, it suffers from low computational efficiency. In response to this problem, we have successfully developed a MC dose calculation package, gCTD, on GPU architecture under the NVIDIA CUDA platform for fast and accurate estimation of the x-ray imaging dose received by a patient during a CT or CBCT scan. Techniques have been developed particularly for the GPU architecture to achieve high computational efficiency. Dose calculations using CBCT scanning geometry in a homogeneous water phantom and a heterogeneous Zubal head phantom have shown good agreement between gCTD and EGSnrc, indicating the accuracy of our code. In terms of improved efficiency, it is found that gCTD attains a speed-up of ~400 times in the homogeneous water ...

  14. Surgical Guides (Patient-Specific Instruments for Pediatric Tibial Bone Sarcoma Resection and Allograft Reconstruction

    Directory of Open Access Journals (Sweden)

    Laura Bellanova

    2013-01-01

    Full Text Available To achieve local control of malignant pediatric bone tumors and to provide satisfactory oncological results, adequate resection margins are mandatory. The local recurrence rate is directly related to inappropriate excision margins. The present study describes a method for decreasing the resection margin width and ensuring that the margins are adequate. This method was developed in the tibia, which is a common site for the most frequent primary bone sarcomas in children. Magnetic resonance imaging (MRI and computerized tomography (CT were used for preoperative planning to define the cutting planes for the tumors: each tumor was segmented on MRI, and the volume of the tumor was coregistered with CT. After preoperative planning, a surgical guide (patient-specific instrument that was fitted to a unique position on the tibia was manufactured by rapid prototyping. A second instrument was manufactured to adjust the bone allograft to fit the resection gap accurately. Pathologic evaluation of the resected specimens showed tumor-free resection margins in all four cases. The technologies described in this paper may improve the surgical accuracy and patient safety in surgical oncology. In addition, these techniques may decrease operating time and allow for reconstruction with a well-matched allograft to obtain stable osteosynthesis.

  15. Surface mesh to voxel data registration for patient-specific anatomical modeling

    Science.gov (United States)

    de Oliveira, Júlia E. E.; Giessler, Paul; Keszei, András.; Herrler, Andreas; Deserno, Thomas M.

    2016-03-01

    Virtual Physiological Human (VPH) models are frequently used for training, planning, and performing medical procedures. The Regional Anaesthesia Simulator and Assistant (RASimAs) project has the goal of increasing the application and effectiveness of regional anesthesia (RA) by combining a simulator of ultrasound-guided and electrical nerve-stimulated RA procedures and a subject-specific assistance system through an integration of image processing, physiological models, subject-specific data, and virtual reality. Individualized models enrich the virtual training tools for learning and improving regional anaesthesia (RA) skills. Therefore, we suggest patient-specific VPH models that are composed by registering the general mesh-based models with patient voxel data-based recordings. Specifically, the pelvis region has been focused for the support of the femoral nerve block. The processing pipeline is composed of different freely available toolboxes such as MatLab, the open Simulation framework (SOFA), and MeshLab. The approach of Gilles is applied for mesh-to-voxel registration. Personalized VPH models include anatomical as well as mechanical properties of the tissues. Two commercial VPH models (Zygote and Anatomium) were used together with 34 MRI data sets. Results are presented for the skin surface and pelvic bones. Future work will extend the registration procedure to cope with all model tissue (i.e., skin, muscle, bone, vessel, nerve, fascia) in a one-step procedure and extrapolating the personalized models to body regions actually being out of the captured field of view.

  16. Validation of a population of patient-specific adult acquired flatfoot deformity models.

    Science.gov (United States)

    Spratley, E Meade; Matheis, Erika A; Hayes, Curtis W; Adelaar, Robert S; Wayne, Jennifer S

    2013-12-01

    Adult acquired flatfoot deformity (AAFD) is a degenerative disease resulting in malalignment of the mid- and hindfoot secondary to posterior tibial tendon dysfunction and increasing implication of ligament pathologies. Despite the complex 3D nature of AAFD, 2D radiographs are still employed to diagnose and stage the disease. Computer modeling techniques allow for accurate 3D recreations of musculoskeletal systems for the investigation of biomechanical factors contributing to disease. Following Institutional Review Board approval, the lower limbs of six diagnosed AAFD sufferers were imaged with MRI, photographs, and X-ray. Next, a radiologist graded the MRI attenuation of eight soft-tissues implicated in AAFD. Six patient-specific rigid-body models were then created and loaded according to patient weight, graded soft-tissues, and extrinsic muscles. Model function was validated using clinically relevant kinematic measures in three planes. Agreement varied depending on the measure, with average absolute deviations of < 7° for angles and <4 mm for distances. Additionally, the clinically favored AP talonavicular coverage angle, ML talo-1st metatarsal angle, and ML 1st cuneiform height showed strong correlations of R(2) = 0.63, 0.75, and 0.85, respectively. Thus, computer modeling offers a promising methodology for the non-invasive investigation of in vivo kinematic behavior in pathologic feet and, once validated, may further be used to investigate biomechanical parameters that are difficult to measure clinically.

  17. Effects of Degree of Surgical Correction for Flatfoot Deformity in Patient-Specific Computational Models.

    Science.gov (United States)

    Spratley, E M; Matheis, E A; Hayes, C W; Adelaar, R S; Wayne, J S

    2015-08-01

    A cohort of adult acquired flatfoot deformity rigid-body models was developed to investigate the effects of isolated tendon transfer with successive levels of medializing calcaneal osteotomy (MCO). Following IRB approval, six diagnosed flatfoot sufferers were subjected to magnetic resonance imaging (MRI) and their scans used to derive patient-specific models. Single-leg stance was modeled, constrained solely through physiologic joint contact, passive soft-tissue tension, extrinsic muscle force, body weight, and without assumptions of idealized mechanical joints. Surgical effect was quantified using simulated mediolateral (ML) and anteroposterior (AP) X-rays, pedobarography, soft-tissue strains, and joint contact force. Radiographic changes varied across states with the largest average improvements for the tendon transfer (TT) + 10 mm MCO state evidenced through ML and AP talo-1st metatarsal angles. Interestingly, 12 of 14 measures showed increased deformity following TT-only, though all increases disappeared with inclusion of MCO. Plantar force distributions showed medial forefoot offloading concomitant with increases laterally such that the most corrected state had 9.0% greater lateral load. Predicted alterations in spring, deltoid, and plantar fascia soft-tissue strain agreed with prior cadaveric and computational works suggesting decreased strain medially with successive surgical repair. Finally, joint contact force demonstrated consistent medial offloading concomitant with variable increases laterally. Rigid-body modeling thus offers novel advantages for the investigation of foot/ankle biomechanics not easily measured in vivo.

  18. Induced radioactivity in a patient-specific collimator used in proton therapy

    CERN Document Server

    Silari, M; Mauro, Egidio; Silari, Marco

    2010-01-01

    This paper discusses the activation of a patient-specific collimator, calculating dose rates, total activities and activities per unit mass of the mixture of radionuclides generated by proton irradiation in the energy range 100-250 MeV. Monte Carlo simulations were first performed for a generic case, using an approximate geometry and on the basis of assumptions on beam intensity and irradiation profile. A collimator used for a prostate cancer treatment was obtained from the MD Anderson Cancer Center (MDACC), Houston, USA, from which a number of samples were cut and analyzed by gamma spectrometry. The results of the gamma spectrometry are compared with the results of Monte Carlo simulations performed using geometrical and irradiation data specific to the unit. The assumptions made for the simulations and their impact on the results are discussed. Dose rate measurements performed in a low-background area at CERN and routine radiation protection measurements at the MDACC are also reported. It is shown that it sh...

  19. PATIENT-SPECIFIC BLOOD DYNAMIC SIMULATIONS IN ASSESSING ENDOVASCULAR OCCLUSION OF INTRACRANIAL ANEURYSMS

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-liang; WANG Sheng-zhang; DING Guang-hong; YANG Xin-jian; LI Hai-yun

    2009-01-01

    According to recent studies, there are various potential predictors for surgical outcome for cerebral aneurysms. An accurate surgical outcome assessment would help make better-informed decisions and avoid the risk of rebleeding. It is well known that hemodynamic factors play an important role in the pathogenesis and treatment of intracranial aneurysms. In this article, a computational fluid dynamic analysis is applied to one patient-specific model of the cerebral aneurysm located at the tip of basilar artery, by which the differences of hemodynamic parameters before and after endovascular treatment may be evaluated. Based on the model, we show that the flow behavior near the neck of the aneurysm sees great differences after endovascular treatment as compared with that before treatment, which also affects the wall shear stress and the displacement distribution. In addition, our whole simulation process is based on a series of CFD commercial software packages, which are easily available for doctors to implement such a method in their daily practice. These results would be used to assess the outcome of endovascular treatment for the aneurysm occlusion.

  20. Experimental unsteady flow study in a patient-specific abdominal aortic aneurysm model

    Science.gov (United States)

    Stamatopoulos, Ch.; Mathioulakis, D. S.; Papaharilaou, Y.; Katsamouris, A.

    2011-06-01

    The velocity field in a patient-specific abdominal aneurysm model including the aorto-iliac bifurcation was measured by 2D PIV. Phase-averaged velocities obtained in 14 planes reveal details of the flow evolution during a cycle. The aneurysm expanding asymmetrically toward the anterior side of the aorta causes the generation of a vortex at its entrance, covering the entire aneurysm bulge progressively before flow peak. The fluid entering the aneurysm impinges on the left side of its distal end, following the axis of the upstream aorta segment, causing an increased flow rate in the left (compared to the right) common iliac artery. High shear stresses appear at the aneurysm inlet and outlet as well as along the posterior wall, varying proportionally to the flow rate. At the same regions, elevated flow disturbances are observed, being intensified at flow peak and during the deceleration phase. Low shear stresses are present in the recirculation region, being two orders of magnitude smaller than the previous ones. At flow peak and during the deceleration phase, a clockwise swirling motion (viewed from the inlet) is present in the aneurysm due to the out of plane curvature of the aorta.

  1. Flow topology in patient-specific abdominal aortic aneurysms during rest and exercise

    Science.gov (United States)

    Arzani, Amirhossein; Shadden, Shawn

    2012-11-01

    Abdominal aortic aneurysm (AAA) is a permanent, localized widening of the abdominal aorta. Flow in AAA is dominated by recirculation, transitional turbulence and low wall shear stress. Image-based CFD has recently enabled high resolution flow data in patient-specific AAA. This study aims to characterize transport in different AAAs, and understand flow topology changes from rest to exercise, which has been a hypothesized therapy due to potential acute changes in flow. Velocity data in 6 patients with different AAA morphology were obtained using image-based CFD under rest and exercise conditions. Finite-time Lyapunov exponent (FTLE) fields were computed from integration of the velocity data to identify dominant Lagrangian coherent structures. The flow topology was compared between rest and exercise conditions. For all patients, the systolic inflow jet resulted in coherent vortex formation. The evolution of this vortex varied greatly between patients and was a major determinant of transport inside the AAA during diastole. During exercise, previously observed stagnant regions were either replaced with undisturbed flow, regions of uniform high mixing, or persisted relatively unchanged. A mix norm measure provided a quantitative assessment of mixing. This work was supported by the National Institutes of Health, grant number 5R21HL108272.

  2. Cell reprogramming for the creation of patient-specific pluripotent stem cells by defined factors

    Institute of Scientific and Technical Information of China (English)

    Huiqun YIN; Heng WANG; Hongguo CAO; Yunhai ZHANG; Yong TAO; Xiaorong ZHANG

    2009-01-01

    Pluripotent stem cells (PSCs), characterized by being able to differentiate into various types of cells, are generally regarded as the most promising sources for cell replacement therapies. However, as typical PSCs, embryonic stem cells (ESCs) are still far away from human clinics so far due to ethical issues and immune rejection response. One way to avoid such problems is to use stem cells derived from autologous somatic cells. Up to date, PSCs could be obtained by reprogramming somatic cells to pluripotent state with approaches including somatic cell nuclear transfer (SCNT), fusion with stem cells, coculture with cells' extracts, and induction with defined factors. Among these, through reprogramming somatic cells directly by retroviral transduction of transcription factors, induced pluripotent stem (iPS) cells have been successfully generated in both mouse and human recently. These iPS cells shared similar morphology and growth properties to ESCs, could express ESCs marker genes, and could produce adult or germline-competent chimaeras and differentiate into a variety of cell types, including germ cells. Moreover, with iPS technique, patient specific PSCs could be derived more easily from handful somatic cells in human without immune rejection responses innately connected to ESCs. Consequently, generation of iPS cells would be of great help to further understand disease mechanisms, drug screening, and cell transplantation therapies as well.In summary,the recent progress in the study of cell reprogramming for the creation of patientspecific pluripotent stem cells, some existing problems, and research perspectives were suggested.

  3. Mild anastomotic stenosis in patient-specific CABG model may enhance graft patency: a new hypothesis.

    Science.gov (United States)

    Huo, Yunlong; Luo, Tong; Guccione, Julius M; Teague, Shawn D; Tan, Wenchang; Navia, José A; Kassab, Ghassan S

    2013-01-01

    It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG) are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40-60%) may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12) patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS) and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI). The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes · cm(-2)) and decreased OSI (<0.02) to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes · cm(-2)). These findings have significant implications for graft adaptation and long-term patency. PMID:24058488

  4. Mild anastomotic stenosis in patient-specific CABG model may enhance graft patency: a new hypothesis.

    Directory of Open Access Journals (Sweden)

    Yunlong Huo

    Full Text Available It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40-60% may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12 patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI. The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes · cm(-2 and decreased OSI (<0.02 to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes · cm(-2. These findings have significant implications for graft adaptation and long-term patency.

  5. Commissioning and validation of COMPASS system for VMAT patient specific quality assurance

    Science.gov (United States)

    Pimthong, J.; Kakanaporn, C.; Tuntipumiamorn, L.; Laojunun, P.; Iampongpaiboon, P.

    2016-03-01

    Pre-treatment patient specific quality assurance (QA) of advanced treatment techniques such as volumetric modulated arc therapy (VMAT) is one of important QA in radiotherapy. The fast and reliable dosimetric device is required. The objective of this study is to commission and validate the performance of COMPASS system for dose verification of VMAT technique. The COMPASS system is composed of an array of ionization detectors (MatriXX) mounted to the gantry using a custom holder and software for the analysis and visualization of QA results. We validated the COMPASS software for basic and advanced clinical application. For the basic clinical study, the simple open field in various field sizes were validated in homogeneous phantom. And the advanced clinical application, the fifteen prostate and fifteen nasopharyngeal cancers VMAT plans were chosen to study. The treatment plans were measured by the MatriXX. The doses and dose-volume histograms (DVHs) reconstructed from the fluence measurements were compared to the TPS calculated plans. And also, the doses and DVHs computed using collapsed cone convolution (CCC) Algorithm were compared with Eclipse TPS calculated plans using Analytical Anisotropic Algorithm (AAA) that according to dose specified in ICRU 83 for PTV.

  6. Patient-specific acetabular shape modelling: comparison among sphere, ellipsoid and conchoid parameterisations.

    Science.gov (United States)

    Cerveri, Pietro; Manzotti, Alfonso; Baroni, Guido

    2014-04-01

    The shape of the human acetabular cup was commonly represented as a hemisphere, but different geometries and patient-specific shapes have been recently proposed in the literature. Our aim was to test the limits of the sphericity assumption by comparing three different parameterisations, namely the sphere, the ellipsoid and the rotational conchoid. Models of hip surfaces, reconstructed from CT scans taken from Caucasian race cadavers and patients, were automatically processed to extract the acetabular surface. Two separate analyses were carried out on the overall acetabular shape, including both the acetabular fossa and the lunate surface (case A) and acetabular cup represented by the lunate surface only (case B). Nonlinear gradient-based and evolutionary computation approaches were implemented for the fitting process. Minor differences from the three idealised geometries were detected (median values of the fitting errors different from both the ellipsoid (p difference was detected between the ellipsoid and the conchoid for case A. Significance of the difference between ellipsoid and sphere (p difference was detected between the ellipsoid and the conchoid. In conclusion, we synthesise that the morphology of the overall acetabular cup can be parameterised both with an ellipsoid shape and with a conchoid shape as well with superior quality than the simple sphere. Differently, if one considers just the lunate surface, better fitting results are expected when using the ellipsoid. PMID:22789071

  7. Reconstruction with a patient-specific titanium implant after a wide anterior chest wall resection

    Science.gov (United States)

    Turna, Akif; Kavakli, Kuthan; Sapmaz, Ersin; Arslan, Hakan; Caylak, Hasan; Gokce, Hasan Suat; Demirkaya, Ahmet

    2014-01-01

    The reconstruction of full-thickness chest wall defects is a challenging problem for thoracic surgeons, particularly after a wide resection of the chest wall that includes the sternum. The location and the size of the defect play a major role when selecting the method of reconstruction, while acceptable cosmetic and functional results remain the primary goal. Improvements in preoperative imaging techniques and reconstruction materials have an important role when planning and performing a wide chest wall resection with a low morbidity rate. In this report, we describe the reconstruction of a wide anterior chest wall defect with a patient-specific custom-made titanium implant. An infected mammary tumour recurrence in a 62-year old female, located at the anterior chest wall including the sternum, was resected, followed by a large custom-made titanium implant. Latissimus dorsi flap and split-thickness graft were also used for covering the implant successfully. A titanium custom-made chest wall implant could be a viable alternative for patients who had large chest wall tumours. PMID:24227881

  8. In Vitro Validation of a Multiscale Patient-Specific Norwood Palliation Model.

    Science.gov (United States)

    Hang, Tianqi; Giardini, Alessandro; Biglino, Giovanni; Conover, Timothy; Figliola, Richard S

    2016-01-01

    In Norwood physiology, shunt size and the occurrence of coarctation can affect hemodynamics significantly. The aim of the study was to validate an in vitro model of the Norwood circulation against clinical measurements for patients presenting differing aortic morphologies. The mock circulatory system used coupled a lumped parameter network of the neonatal Norwood circulation with modified Blalock-Taussig (mBT) shunt with a three-dimensional aorta model. Five postoperative aortic arch anatomies of differing morphologies were reconstructed from imaging data, and the system was tuned to patient-specific clinical values. Experimentally measured flow rates and pressures were compared with clinical measurements. Time-based experimental and clinical pressure and flow signals within the aorta and pulmonary circulation branches agreed closely (0.72 mBT shunt by showing it capable of reproducing clinical pressure and flow rates at various positions of the circulation with very good fidelity across a range of patient physiologies and morphologies. The multiscale aspect of the model provides a means to study variables in isolation with their effects both locally and at the system level. The model serves as a tool to further the understanding of the complex physiology of single-ventricle circulation. PMID:26771396

  9. The future of spine surgery: New horizons in the treatment of spinal disorders

    OpenAIRE

    Kazemi, Noojan; Crew, Laura K.; Tredway, Trent L.

    2013-01-01

    Background and Methods: As with any evolving surgical discipline, it is difficult to predict the future of the practice and science of spine surgery. In the last decade, there have been dramatic developments in both the techniques as well as the tools employed in the delivery of better outcomes to patients undergoing such surgery. In this article, we explore four specific areas in spine surgery: namely the role of minimally invasive spine surgery; motion preservation; robotic-aided surgery an...

  10. Patient-specific simulation of stent-graft deployment within an abdominal aortic aneurysm

    CERN Document Server

    Perrin, David; Avril, Stéphane; Albertini, Jean-Noël; Orgéas, Laurent; Geindreau, Christian; Dumenil, Aurélien; Goksu, Cemil

    2014-01-01

    In this study, finite element analysis is used to simulate the surgical deployment procedure of a bifurcated stent-graft on a real patient's arterial geometry. The stent-graft is modeled using realistic constitutive properties for both the stent and most importantly for the graft. The arterial geometry is obtained from pre-operative imaging exam. The obtained results are in good agreement with the post-operative imaging data. As the whole computational time was reduced to less than 2 hours, this study constitutes an essential step towards predictive planning simulations of aneurysmal endovascular surgery

  11. Nanomedicine-Based Neuroprotective Strategies in Patient Specific-iPSC and Personalized Medicine

    Directory of Open Access Journals (Sweden)

    Shih-Fan Jang

    2014-03-01

    -based neuroprotective manipulations in patient specific-iPSCs and personalized medicine.

  12. Graph-cuts based reconstructing patient specific right ventricle: first human study.

    Science.gov (United States)

    Zhong, Liang; Wan, Min; Su, Yi; Teo, Soo Kng; Lim, Chi Wan; Zhao, Xiaodan; Zhang, Jun-Mei; Su, Bo Yang; Tan, Ju Le; Tan, Ru San

    2014-01-01

    Right ventricular (RV) function is increasingly recognized to play an important role in the clinical status and long-term outcome in patients with congenital heart disease as well as ischemic cardiomyopathy with left ventricular dysfunction. However, quantification of RV characteristics and function are still challenging due to its complex morphology and its thin wall with coarse trabeculations. To assess RV functions quantitatively, establishing the patient-specific model from medical images is a prerequisite task. This study aims to develop a novel method for RV model reconstruction. Magnetic resonance images were acquired and preprocessed. Contours of right ventricle, right atrium and pulmonary artery were manually delineated at all slices and all time frames. The contour coordinates as well as the medical image specifications such as image pixel resolution and slick thickness were exported. The contours were transformed to the correct positions. Reorientation and matching were executed in between neighboring contours; extrapolation and interpolation were conducted upon all contours. After preprocessing, the more dense point set was reconstructed through a variational tool. A Delaunay-based tetrahedral mesh was generated on the region of interest. The weighted minimal surface model was used to describe RV surface. The graphcuts technique, i.e., max-flow/min-cut algorithm, was applied to minimize the energy defined by the model. The reconstructed surface was extracted from the mesh according to the mincut. Smoothing and remeshing were performed. The CPU time to reconstruct the model for one frame was approximately 2 minutes. In 10 consecutive subjects referred for cardiac MRI (80% female), right ventricular volumes were measured using our method against the commercial available CMRtools package. The results demonstrated that there was a significant correlation in end-diastolic and end-systolic volumes between our method and commercial software (r= 0.89 for end

  13. Patient-Specific, Time-Varying Predictors of Post-ICU Informal Caregiver Burden

    Science.gov (United States)

    Schulz, Richard; Chelluri, Lakshmipathi; Pinsky, Michael R.

    2010-01-01

    Background: The outcomes of informal caregivers of survivors of critical illness likely depend on patient characteristics, which may change over time. To date, few studies have examined patient-specific predictors of post-ICU informal caregiver burden, and none has tested whether predictors vary after hospital discharge. Methods: We designed a prospective, longitudinal observational study, enrolling 48 patient-caregiver dyads from four ICUs in a university hospital. Informal caregiver depression symptoms were measured with the Center for Epidemiologic Studies Depression scale. Lifestyle disruption was measured with the Activity Restriction Scale. Linear regression models were built to test for patient- and caregiver-specific predictors of depression symptoms and lifestyle disruption 2, 6, and 12 months after ICU admission. Results: Patients had a mean (SD) age of 52.5 (19.7) years, 67% were men, median (interquartile range) Acute Physiology and Chronic Health Evaluation score was 52 (38.5, 65). The caregivers had a mean (SD) age of 52.8 (12.8) years, 91.2% were women, and 48% were spouses. Predictors of caregiver depression symptoms were patient gender (men) at 2 and 12 months and tracheostomy at 12 months. Predictors of lifestyle disruption were patient education (more common among high school graduates) and patient gender (men) at 2 months, and tracheostomy, functional dependency, and patient gender (men) at 12 months. Conclusions: The determinants of post-ICU informal caregiver burden likely depend on characteristics of the patient as well as the caregiver and may vary over time. Further research is necessary to better understand the longitudinal determinants of burden in order to develop more effective caregiver interventions. PMID:19762552

  14. Accuracy of patient specific organ-dose estimates obtained using an automated image segmentation algorithm

    Science.gov (United States)

    Gilat-Schmidt, Taly; Wang, Adam; Coradi, Thomas; Haas, Benjamin; Star-Lack, Josh

    2016-03-01

    The overall goal of this work is to develop a rapid, accurate and fully automated software tool to estimate patient-specific organ doses from computed tomography (CT) scans using a deterministic Boltzmann Transport Equation solver and automated CT segmentation algorithms. This work quantified the accuracy of organ dose estimates obtained by an automated segmentation algorithm. The investigated algorithm uses a combination of feature-based and atlas-based methods. A multiatlas approach was also investigated. We hypothesize that the auto-segmentation algorithm is sufficiently accurate to provide organ dose estimates since random errors at the organ boundaries will average out when computing the total organ dose. To test this hypothesis, twenty head-neck CT scans were expertly segmented into nine regions. A leave-one-out validation study was performed, where every case was automatically segmented with each of the remaining cases used as the expert atlas, resulting in nineteen automated segmentations for each of the twenty datasets. The segmented regions were applied to gold-standard Monte Carlo dose maps to estimate mean and peak organ doses. The results demonstrated that the fully automated segmentation algorithm estimated the mean organ dose to within 10% of the expert segmentation for regions other than the spinal canal, with median error for each organ region below 2%. In the spinal canal region, the median error was 7% across all data sets and atlases, with a maximum error of 20%. The error in peak organ dose was below 10% for all regions, with a median error below 4% for all organ regions. The multiple-case atlas reduced the variation in the dose estimates and additional improvements may be possible with more robust multi-atlas approaches. Overall, the results support potential feasibility of an automated segmentation algorithm to provide accurate organ dose estimates.

  15. Three-dimensional left ventricular segmentation from magnetic resonance imaging for patient-specific modelling purposes

    Science.gov (United States)

    Caiani, Enrico G.; Colombo, Andrea; Pepi, Mauro; Piazzese, Concetta; Maffessanti, Francesco; Lang, Roberto M.; Carminati, Maria Chiara

    2014-01-01

    Aims To propose a nearly automated left ventricular (LV) three-dimensional (3D) surface segmentation procedure, based on active shape modelling (ASM) and built on a database of 3D echocardiographic (3DE) LV surfaces, for cardiac magnetic resonance (CMR) images, and to test its accuracy for LV volumes computation compared with ‘gold standard’ manual tracings and discs-summation method. Methods and results The ASM was created based on segmented LV surfaces (4D LV analysis, Tomtec) from 3DE datasets of 205 patients. Then, it was applied to the cardiac magnetic resonance imaging short-axis (SAX) images stack of 12 consecutive patients. After proper realignment using two- and four-chambers CMR long-axis views both as reference and for initializing LV apex and base (six points in total), the ASM was iteratively and automatically updated to match the information of all the SAX planes contemporaneously, resulting in an endocardial LV 3D mesh from which volume was directly derived. The same CMR images were analysed by an experienced cardiologist to derive end-diastolic and end-systolic volumes. Linear correlation and Bland–Altman analyses were applied vs. the manual ‘gold standard’. Active shape modelling results showed high correlations with manual values both for LV volumes (r2 > 0.98) and ejection fraction (EF) (r2 > 0.90), non-significant biases and narrow limits of agreement. Conclusion The proposed method resulted in accurate detection of 3D LV endocardial surfaces, which lead to fast and reliable measurements of LV volumes and EF when compared with manual tracing of CMR SAX images. The segmented 3D mesh, including a realistic LV apex and base, could constitute a novel starting point for more realistic patient-specific finite element modelling. PMID:25362176

  16. PATIENT-SPECIFIC DATA FUSION FOR CANCER STRATIFICATION AND PERSONALISED TREATMENT.

    Science.gov (United States)

    Gligorijević, Vladimir; Malod-Dognin, Noël; Pržulj, Nataša

    2016-01-01

    According to Cancer Research UK, cancer is a leading cause of death accounting for more than one in four of all deaths in 2011. The recent advances in experimental technologies in cancer research have resulted in the accumulation of large amounts of patient-specific datasets, which provide complementary information on the same cancer type. We introduce a versatile data fusion (integration) framework that can effectively integrate somatic mutation data, molecular interactions and drug chemical data to address three key challenges in cancer research: stratification of patients into groups having different clinical outcomes, prediction of driver genes whose mutations trigger the onset and development of cancers, and repurposing of drugs treating particular cancer patient groups. Our new framework is based on graph-regularised non-negative matrix tri-factorization, a machine learning technique for co-clustering heterogeneous datasets. We apply our framework on ovarian cancer data to simultaneously cluster patients, genes and drugs by utilising all datasets.We demonstrate superior performance of our method over the state-of-the-art method, Network-based Stratification, in identifying three patient subgroups that have significant differences in survival outcomes and that are in good agreement with other clinical data. Also, we identify potential new driver genes that we obtain by analysing the gene clusters enriched in known drivers of ovarian cancer progression. We validated the top scoring genes identified as new drivers through database search and biomedical literature curation. Finally, we identify potential candidate drugs for repurposing that could be used in treatment of the identified patient subgroups by targeting their mutated gene products. We validated a large percentage of our drug-target predictions by using other databases and through literature curation. PMID:26776197

  17. On the use of biomathematical models in patient-specific IMRT dose QA

    Energy Technology Data Exchange (ETDEWEB)

    Zhen Heming [UT Southwestern Medical Center, Dallas, Texas 75390 (United States); Nelms, Benjamin E. [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Tome, Wolfgang A. [Department of Radiation Oncology, Division of Medical Physics, Montefiore Medical Center and Institute of Onco-Physics, Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

    2013-07-15

    Purpose: To investigate the use of biomathematical models such as tumor control probability (TCP) and normal tissue complication probability (NTCP) as new quality assurance (QA) metrics.Methods: Five different types of error (MLC transmission, MLC penumbra, MLC tongue and groove, machine output, and MLC position) were intentionally induced to 40 clinical intensity modulated radiation therapy (IMRT) patient plans (20 H and N cases and 20 prostate cases) to simulate both treatment planning system errors and machine delivery errors in the IMRT QA process. The changes in TCP and NTCP for eight different anatomic structures (H and N: CTV, GTV, both parotids, spinal cord, larynx; prostate: CTV, rectal wall) were calculated as the new QA metrics to quantify the clinical impact on patients. The correlation between the change in TCP/NTCP and the change in selected DVH values was also evaluated. The relation between TCP/NTCP change and the characteristics of the TCP/NTCP curves is discussed.Results:{Delta}TCP and {Delta}NTCP were summarized for each type of induced error and each structure. The changes/degradations in TCP and NTCP caused by the errors vary widely depending on dose patterns unique to each plan, and are good indicators of each plan's 'robustness' to that type of error.Conclusions: In this in silico QA study the authors have demonstrated the possibility of using biomathematical models not only as patient-specific QA metrics but also as objective indicators that quantify, pretreatment, a plan's robustness with respect to possible error types.

  18. Patient-specific FDG dosimetry for adult males, adult females, and very low birth weight infants

    Science.gov (United States)

    Niven, Erin

    Fluorodeoxyglucose is the most commonly used radiopharmaceutical in Positron Emission Tomography, with applications in neurology, cardiology, and oncology. Despite its routine use worldwide, the radiation absorbed dose estimates from FDG have been based primarily on data obtained from two dogs studied in 1977 and 11 adults (most likely males) studied in 1982. In addition, the dose estimates calculated for FDG have been centered on the adult male, with little or no mention of variations in the dose estimates due to sex, age, height, weight, nationality, diet, or pathological condition. Through an extensive investigation into the Medical Internal Radiation Dose schema for calculating absorbed doses, I have developed a simple patient-specific equation; this equation incorporates the parameters necessary for alterations to the mathematical values of the human model to produce an estimate more representative of the individual under consideration. I have used this method to determine the range of absorbed doses to FDG from the collection of a large quantity of biological data obtained in adult males, adult females, and very low birth weight infants. Therefore, a more accurate quantification of the dose to humans from FDG has been completed. My results show that per unit administered activity, the absorbed dose from FDG is higher for infants compared to adults, and the dose for adult women is higher than for adult men. Given an injected activity of approximately 3.7 MBq kg-1, the doses for adult men, adult women, and full-term newborns would be on the order of 5.5, 7.1, and 2.8 mSv, respectively. These absorbed doses are comparable to the doses received from other nuclear medicine procedures.

  19. AIDS.gov

    Science.gov (United States)

    ... concerns. Search Services Share This Help National HIV/AIDS Strategy Check out NHAS's latest progress in the ... from AIDS.gov Read more AIDS.gov tweets AIDS.gov HIV/AIDS Basics • Federal Resources • Using New ...

  20. Macroeconomic Issues in Foreign Aid

    DEFF Research Database (Denmark)

    Hjertholm, Peter; Laursen, Jytte; White, Howard

    foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,......foreign aid, macroeconomics of aid, gap models, aid fungibility, fiscal response models, foreign debt,...

  1. Methods for intraoperative, sterile pose-setting of patient-specific microstereotactic frames

    Science.gov (United States)

    Vollmann, Benjamin; Müller, Samuel; Kundrat, Dennis; Ortmaier, Tobias; Kahrs, Lüder A.

    2015-03-01

    This work proposes new methods for a microstereotactic frame based on bone cement fixation. Microstereotactic frames are under investigation for minimal invasive temporal bone surgery, e.g. cochlear implantation, or for deep brain stimulation, where products are already on the market. The correct pose of the microstereotactic frame is either adjusted outside or inside the operating room and the frame is used for e.g. drill or electrode guidance. We present a patientspecific, disposable frame that allows intraoperative, sterile pose-setting. Key idea of our approach is bone cement between two plates that cures while the plates are positioned with a mechatronics system in the desired pose. This paper includes new designs of microstereotactic frames, a system for alignment and first measurements to analyze accuracy and applicable load.

  2. HIV and AIDS

    Science.gov (United States)

    ... Got Homework? Here's Help White House Lunch Recipes HIV and AIDS KidsHealth > For Kids > HIV and AIDS ... actually the virus that causes the disease AIDS. HIV Hurts the Immune System People who are HIV ...

  3. Nosebleed, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Nosebleed, First Aid A A A First Aid for Nosebleed: View ... of the nose, causing bleeding into the throat. First Aid Guide The following self-care measures are recommended: ...

  4. Splinter, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Splinter, First Aid A A A First Aid for Splinter: View ... wet, it makes the area prone to infection. First Aid Guide Self-care measures to remove a splinter ...

  5. HIV-AIDS Connection

    Science.gov (United States)

    ... Content Marketing Share this: Main Content Area The HIV-AIDS Connection AIDS was first recognized in 1981 ... cancers. Why is there overwhelming scientific consensus that HIV causes AIDS? Before HIV infection became widespread in ...

  6. Heart attack first aid

    Science.gov (United States)

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... A heart attack occurs when the blood flow that carries oxygen to the heart is blocked. The heart muscle ...

  7. Assessment of DICOM Viewers Capable of Loading Patient-specific 3D Models Obtained by Different Segmentation Platforms in the Operating Room.

    Science.gov (United States)

    Lo Presti, Giuseppe; Carbone, Marina; Ciriaci, Damiano; Aramini, Daniele; Ferrari, Mauro; Ferrari, Vincenzo

    2015-10-01

    Patient-specific 3D models obtained by the segmentation of volumetric diagnostic images play an increasingly important role in surgical planning. Surgeons use the virtual models reconstructed through segmentation to plan challenging surgeries. Many solutions exist for the different anatomical districts and surgical interventions. The possibility to bring the 3D virtual reconstructions with native radiological images in the operating room is essential for fostering the use of intraoperative planning. To the best of our knowledge, current DICOM viewers are not able to simultaneously connect to the picture archiving and communication system (PACS) and import 3D models generated by external platforms to allow a straight integration in the operating room. A total of 26 DICOM viewers were evaluated: 22 open source and four commercial. Two DICOM viewers can connect to PACS and import segmentations achieved by other applications: Synapse 3D® by Fujifilm and OsiriX by University of Geneva. We developed a software network that converts diffuse visual tool kit (VTK) format 3D model segmentations, obtained by any software platform, to a DICOM format that can be displayed using OsiriX or Synapse 3D. Both OsiriX and Synapse 3D were suitable for our purposes and had comparable performance. Although Synapse 3D loads native images and segmentations faster, the main benefits of OsiriX are its user-friendly loading of elaborated images and it being both free of charge and open source. PMID:25739346

  8. Patient-Specific Prosthetic Fingers by Remote Collaboration - A Case Study

    CERN Document Server

    Cabibihan, John-John

    2011-01-01

    The concealment of amputation through prosthesis usage can shield an amputee from social stigma and help improve the emotional healing process especially at the early stages of hand or finger loss. However, the traditional techniques in prosthesis fabrication defy this as the patients need numerous visits to the clinics for measurements, fitting and follow-ups. This paper presents a method for constructing a prosthetic finger through online collaboration with the designer. The main input from the amputee comes from the Computer Tomography (CT) data in the region of the affected and the non-affected fingers. These data are sent over the internet and the prosthesis is constructed using visualization, computer-aided design and manufacturing tools. The finished product is then shipped to the patient. A case study with a single patient having an amputated ring finger at the proximal interphalangeal joint shows that the proposed method has a potential to address the patient's psychosocial concerns and minimize the ...

  9. A Patient-Specific Foot Model for the Estimate of Ankle Joint Forces in Patients with Juvenile Idiopathic Arthritis.

    Science.gov (United States)

    Prinold, Joe A I; Mazzà, Claudia; Di Marco, Roberto; Hannah, Iain; Malattia, Clara; Magni-Manzoni, Silvia; Petrarca, Maurizio; Ronchetti, Anna B; Tanturri de Horatio, Laura; van Dijkhuizen, E H Pieter; Wesarg, Stefan; Viceconti, Marco

    2016-01-01

    Juvenile idiopathic arthritis (JIA) is the leading cause of childhood disability from a musculoskeletal disorder. It generally affects large joints such as the knee and the ankle, often causing structural damage. Different factors contribute to the damage onset, including altered joint loading and other mechanical factors, associated with pain and inflammation. The prediction of patients' joint loading can hence be a valuable tool in understanding the disease mechanisms involved in structural damage progression. A number of lower-limb musculoskeletal models have been proposed to analyse the hip and knee joints, but juvenile models of the foot are still lacking. This paper presents a modelling pipeline that allows the creation of juvenile patient-specific models starting from lower limb kinematics and foot and ankle MRI data. This pipeline has been applied to data from three children with JIA and the importance of patient-specific parameters and modelling assumptions has been tested in a sensitivity analysis focused on the variation of the joint reaction forces. This analysis highlighted the criticality of patient-specific definition of the ankle joint axes and location of the Achilles tendon insertions. Patient-specific detection of the Tibialis Anterior, Tibialis Posterior, and Peroneus Longus origins and insertions were also shown to be important. PMID:26374518

  10. Geometrical aspects of patient-specific modelling of the intervertebral disc: collagen fibre orientation and residual stress distribution.

    Science.gov (United States)

    Marini, Giacomo; Studer, Harald; Huber, Gerd; Püschel, Klaus; Ferguson, Stephen J

    2016-06-01

    Patient-specific modelling of the spine is a powerful tool to explore the prevention and the treatment of injuries and pathologies. Albeit several methods have been proposed for the discretization of the bony structures, the efficient representation of the intervertebral disc anisotropy remains a challenge, especially with complex geometries. Furthermore, the swelling of the disc's nucleus pulposus is normally added to the model after geometry definition, at the cost of changes of the material properties and an unrealistic description of the prestressed state. The aim of this study was to develop techniques, which preserve the patient-specific geometry of the disc and allow the representation of the system anisotropy and residual stresses, independent of the system discretization. Depending on the modelling features, the developed approaches resulted in a response of patient-specific models that was in good agreement with the physiological response observed in corresponding experiments. The proposed methods represent a first step towards the development of patient-specific models of the disc which respect both the geometry and the mechanical properties of the specific disc. PMID:26243011

  11. Transcriptome profiling of patient-specific human iPSC-cardiomyocytes predicts individual drug safety and efficacy responses in vitro

    Science.gov (United States)

    Matsa, Elena; Burridge, Paul W.; Yu, Kun-Hsing; Ahrens, John H.; Termglinchan, Vittavat; Wu, Haodi; Liu, Chun; Shukla, Praveen; Sayed, Nazish; Churko, Jared M.; Shao, Ningyi; Woo, Nicole A.; Chao, Alexander S.; Gold, Joseph D.; Karakikes, Ioannis; Snyder, Michael P.; Wu, Joseph C.

    2016-01-01

    SUMMARY Understanding individual susceptibility to drug-induced cardiotoxicity is key to improving patient safety and preventing drug attrition. Human induced pluripotent stem cells (hiPSCs) enable the study of pharmacological and toxicological responses in patient-specific cardiomyocytes (CMs), and may serve as preclinical platforms for precision medicine. Transcriptome profiling in hiPSC-CMs from seven individuals lacking known cardiovascular disease-associated mutations, and in three isogenic human heart tissue and hiPSC-CM pairs, showed greater inter-patient variation than intra-patient variation, verifying that reprogramming and differentiation preserve patient-specific gene expression, particularly in metabolic and stress-response genes. Transcriptome-based toxicology analysis predicted and risk-stratified patient-specific susceptibility to cardiotoxicity, and functional assays in hiPSC-CMs using tacrolimus and rosiglitazone, drugs targeting pathways predicted to produce cardiotoxicity, validated inter-patient differential responses. CRISPR/Cas9-mediated pathway correction prevented drug-induced cardiotoxicity. Our data suggest that hiPSC-CMs can be used in vitro to predict and validate patient-specific drug safety and efficacy, potentially enabling future clinical approaches to precision medicine. PMID:27545504

  12. Automatic construction of patient-specific finite-element mesh of the spine from IVDs and vertebra segmentations

    Science.gov (United States)

    Castro-Mateos, Isaac; Pozo, Jose M.; Lazary, Aron; Frangi, Alejandro F.

    2016-03-01

    Computational medicine aims at developing patient-specific models to help physicians in the diagnosis and treatment selection for patients. The spine, and other skeletal structures, is an articulated object, composed of rigid bones (vertebrae) and non-rigid parts (intervertebral discs (IVD), ligaments and muscles). These components are usually extracted from different image modalities, involving patient repositioning. In the case of the spine, these models require the segmentation of IVDs from MR and vertebrae from CT. In the literature, there exists a vast selection of segmentations methods, but there is a lack of approaches to align the vertebrae and IVDs. This paper presents a method to create patient-specific finite element meshes for biomechanical simulations, integrating rigid and non-rigid parts of articulated objects. First, the different parts are aligned in a complete surface model. Vertebrae extracted from CT are rigidly repositioned in between the IVDs, initially using the IVDs location and then refining the alignment using the MR image with a rigid active shape model algorithm. Finally, a mesh morphing algorithm, based on B-splines, is employed to map a template finite-element (volumetric) mesh to the patient-specific surface mesh. This morphing reduces possible misalignments and guarantees the convexity of the model elements. Results show that the accuracy of the method to align vertebrae into MR, together with IVDs, is similar to that of the human observers. Thus, this method is a step forward towards the automation of patient-specific finite element models for biomechanical simulations.

  13. Patient-Specific Dosimetry and Radiobiological Modeling of Targeted Radionuclide Therapy Grant - final report

    Energy Technology Data Exchange (ETDEWEB)

    George Sgouros, Ph.D.

    2007-03-20

    radionuclide therapy to obtain normal organ and tumor dose vs. response correlations. Completion of the aims outlined above will make it possible to perform patient-specific dosimetry that incorporates considerations likely to provide robust dose-response relationships. Such an advance will improve targeted radionuclide therapy by making it possible to adopt treatment planning methodologies.

  14. Using patient-specific phantoms to evaluate deformable image registration algorithms for adaptive radiation therapy.

    Science.gov (United States)

    Stanley, Nick; Glide-Hurst, Carri; Kim, Jinkoo; Adams, Jeffrey; Li, Shunshan; Wen, Ning; Chetty, Indrin J; Zhong, Hualiang

    2013-11-04

    The quality of adaptive treatment planning depends on the accuracy of its underlying deformable image registration (DIR). The purpose of this study is to evaluate the performance of two DIR algorithms, B-spline-based deformable multipass (DMP) and deformable demons (Demons), implemented in a commercial software package. Evaluations were conducted using both computational and physical deformable phantoms. Based on a finite element method (FEM), a total of 11 computational models were developed from a set of CT images acquired from four lung and one prostate cancer patients. FEM generated displacement vector fields (DVF) were used to construct the lung and prostate image phantoms. Based on a fast-Fourier transform technique, image noise power spectrum was incorporated into the prostate image phantoms to create simulated CBCT images. The FEM-DVF served as a gold standard for verification of the two registration algorithms performed on these phantoms. The registration algorithms were also evaluated at the homologous points quantified in the CT images of a physical lung phantom. The results indicated that the mean errors of the DMP algorithm were in the range of 1.0 ~ 3.1 mm for the computational phantoms and 1.9 mm for the physical lung phantom. For the computational prostate phantoms, the corresponding mean error was 1.0-1.9 mm in the prostate, 1.9-2.4mm in the rectum, and 1.8-2.1 mm over the entire patient body. Sinusoidal errors induced by B-spline interpolations were observed in all the displacement profiles of the DMP registrations. Regions of large displacements were observed to have more registration errors. Patient-specific FEM models have been developed to evaluate the DIR algorithms implemented in the commercial software package. It has been found that the accuracy of these algorithms is patient dependent and related to various factors including tissue deformation magnitudes and image intensity gradients across the regions of interest. This may suggest that

  15. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119

    Energy Technology Data Exchange (ETDEWEB)

    Ashmeg, S; Zhang, Y; O' Daniel, J; Yin, F; Ren, L [Duke University Medical Center, Durham, NC (United States)

    2014-06-01

    Purpose: To evaluate the accuracy of a 3D patient specific QA tool by analysis of the results produced from associated software in homogenous phantom and heterogonous patient CT. Methods: IMRT and VMAT plans of five test suites introduced by TG119 were created in ECLIPSE on a solid water phantom. The ten plans -of increasing complexity- were delivered to Delta4 to give a 3D measurement. The Delta4's “Anatomy” software uses the measured dose to back-calculate the energy fluence of the delivered beams, which is used for dose calculation in a patient CT using a pencilbeam algorithm. The effect of the modulated beams' complexity on the accuracy of the “Anatomy” calculation was evaluated. Both measured and Anatomy doses were compared to ECLIPSE calculation using 3% - 3mm gamma criteria.We also tested the effect of heterogeneity by analyzing the results of “Anatomy” calculation on a Brain VMAT and a 3D conformal lung cases. Results: In homogenous phantom, the gamma passing rates were found to be as low as 74.75% for a complex plan with high modulation. The mean passing rates were 91.47% ± 6.35% for “Anatomy” calculation and 99.46% ± 0.62% for Delta4 measurements.As for the heterogeneous cases, the rates were 96.54%±3.67% and 83.87%±9.42% for Brain VMAT and 3D lung respectively. This increased error in the lung case could be due to the use of the pencil beam algorithm as opposed to the AAA used by ECLIPSE.Also, gamma analysis showed high discrepancy along the beam edge in the “Anatomy” calculated results. This suggests a poor beam modeling in the penumbra region. Conclusion: The results show various sources of errors in “Anatomy” calculations. These include beam modeling in the penumbra region, complexity of a modulated beam (shown in homogenous phantom and brain cases) and dose calculation algorithms (3D conformal lung case)

  16. An in vitro assessment of the cerebral hemodynamics through three patient specific circle of Willis geometries.

    Science.gov (United States)

    Fahy, Paul; Delassus, Patrick; McCarthy, Peter; Sultan, Sheriff; Hynes, Niamh; Morris, Liam

    2014-01-01

    The Circle of Willis (CoW) is a complex pentagonal network comprised of fourteen cerebral vessels located at the base of the brain. The collateral flow feature within the circle of Willis allows the ability to maintain cerebral perfusion of the brain. Unfortunately, this collateral flow feature can create undesirable flow impact locations due to anatomical variations within the CoW. The interaction between hemodynamic forces and the arterial wall are believed to be involved in the formation of cerebral aneurysms, especially at irregular geometries such as tortuous segments, bends, and bifurcations. The highest propensity of aneurysm formation is known to form at the anterior communicating artery (AcoA) and at the junctions of the internal carotid and posterior communicating arteries (PcoAs). Controversy still remains as to the existence of blood flow paths through the communicating arteries for a normal CoW. This paper experimentally describes the hemodynamic conditions through three thin walled patient specific models of a complete CoW based on medical images. These models were manufactured by a horizontal dip spin coating method and positioned within a custom made cerebral testing system that simulated symmetrical physiological afferent flow conditions through the internal carotid and vertebral arteries. The dip spin coating procedure produced excellent dimensional accuracy. There was an average of less than 4% variation in diameters and wall thicknesses throughout all manufactured CoW models. Our cerebral test facility demonstrated excellent cycle to cycle repeatability, with variations of less than 2% and 1% for the time and cycle averaged flow rates, respectively. The peak systolic flow rates had less than a 4% variation. Our flow visualizations showed four independent flow sources originating from all four inlet arteries impacting at and crossing the AcoA with bidirectional cross flows. The flow paths entering the left and right vertebral arteries dissipated

  17. Segmenting CT prostate images using population and patient-specific statistics for radiotherapy

    International Nuclear Information System (INIS)

    Purpose: In the segmentation of sequential treatment-time CT prostate images acquired in image-guided radiotherapy, accurately capturing the intrapatient variation of the patient under therapy is more important than capturing interpatient variation. However, using the traditional deformable-model-based segmentation methods, it is difficult to capture intrapatient variation when the number of samples from the same patient is limited. This article presents a new deformable model, designed specifically for segmenting sequential CT images of the prostate, which leverages both population and patient-specific statistics to accurately capture the intrapatient variation of the patient under therapy. Methods: The novelty of the proposed method is twofold: First, a weighted combination of gradient and probability distribution function (PDF) features is used to build the appearance model to guide model deformation. The strengths of each feature type are emphasized by dynamically adjusting the weight between the profile-based gradient features and the local-region-based PDF features during the optimization process. An additional novel aspect of the gradient-based features is that, to alleviate the effect of feature inconsistency in the regions of gas and bone adjacent to the prostate, the optimal profile length at each landmark is calculated by statistically investigating the intensity profile in the training set. The resulting gradient-PDF combined feature produces more accurate and robust segmentations than general gradient features. Second, an online learning mechanism is used to build shape and appearance statistics for accurately capturing intrapatient variation. Results: The performance of the proposed method was evaluated on 306 images of the 24 patients. Compared to traditional gradient features, the proposed gradient-PDF combination features brought 5.2% increment in the success ratio of segmentation (from 94.1% to 99.3%). To evaluate the effectiveness of online

  18. Patient specific optimization-based treatment planning for catheter-based ultrasound hyperthermia and thermal ablation

    Science.gov (United States)

    Prakash, Punit; Chen, Xin; Wootton, Jeffery; Pouliot, Jean; Hsu, I.-Chow; Diederich, Chris J.

    2009-02-01

    A 3D optimization-based thermal treatment planning platform has been developed for the application of catheter-based ultrasound hyperthermia in conjunction with high dose rate (HDR) brachytherapy for treating advanced pelvic tumors. Optimal selection of applied power levels to each independently controlled transducer segment can be used to conform and maximize therapeutic heating and thermal dose coverage to the target region, providing significant advantages over current hyperthermia technology and improving treatment response. Critical anatomic structures, clinical target outlines, and implant/applicator geometries were acquired from sequential multi-slice 2D images obtained from HDR treatment planning and used to reconstruct patient specific 3D biothermal models. A constrained optimization algorithm was devised and integrated within a finite element thermal solver to determine a priori the optimal applied power levels and the resulting 3D temperature distributions such that therapeutic heating is maximized within the target, while placing constraints on maximum tissue temperature and thermal exposure of surrounding non-targeted tissue. This optimizationbased treatment planning and modeling system was applied on representative cases of clinical implants for HDR treatment of cervix and prostate to evaluate the utility of this planning approach. The planning provided significant improvement in achievable temperature distributions for all cases, with substantial increase in T90 and thermal dose (CEM43T90) coverage to the hyperthermia target volume while decreasing maximum treatment temperature and reducing thermal dose exposure to surrounding non-targeted tissues and thermally sensitive rectum and bladder. This optimization based treatment planning platform with catheter-based ultrasound applicators is a useful tool that has potential to significantly improve the delivery of hyperthermia in conjunction with HDR brachytherapy. The planning platform has been extended

  19. On the evaluation of patient specific IMRT QA using EPID, dynalog files and patient anatomy

    Directory of Open Access Journals (Sweden)

    Dewayne Lee Defoor

    2014-03-01

    Full Text Available Purpose: This research, investigates the viability of using the Electronic portal imaging device (EPID coupled with the treatment planning system (TPS, to calculate the doses delivered and verify agreement with the treatment plan. The results of QA analysis using the EPID, Delta4 and fluence calculations using the multi-leaf collimator (MLC dynalog files on 10 IMRT patients are presented in this study.Methods: EPID Fluence Images in integrated mode and Dynalog files for each field were acquired for 10 IMRT (6MV patients and processed through an in house MatLab program to create an opening density matrix (ODM which was used as the input fluence for dose calculation with the TPS (Pinnacle3, Philips. The EPID used in this study was the aSi1000 Varian on a Novalis TX linac equipped with high definition MLC. The resulting dose distributions were then exported to VeriSoft (PTW where a 3D gamma was calculated using 3 mm-3% criteria. The Scandidos Delta4 phantom was also used to measure a 2D dose distribution for all 10 patients and a 2D gamma was calculated for each patient using the Delta4 software.Results: The average 3D gamma for all 10 patients using the EPID images was 98.2% ± 2.6%. The average 3D gamma using the dynalog files was 94.6% ± 4.9%. The average 2D gamma from the Delta4 was 98.1% ± 2.5%. The minimum 3D gamma for the EPID and dynalog reconstructed dose distributions was found on the same patient which had a very large PTV, requiring the jaws to open to the maximum field size. Conclusion: Use of the EPID, combined with a TPS is a viable method for QA of IMRT plans. A larger ODM size can be implemented to accommodate larger field sizes. An adaptation of this process to Volumetric Arc Therapy (VMAT is currently under way.-----------------------------Cite this article as: Defoor D, Mavroidis P, Quino L, Gutierrez A, Papanikolaou N, Stathakis S. On the evaluation of patient specific IMRT QA using EPID, dynalog files and patient anatomy

  20. SU-E-T-159: Evaluation of a Patient Specific QA Tool Based On TG119

    International Nuclear Information System (INIS)

    Purpose: To evaluate the accuracy of a 3D patient specific QA tool by analysis of the results produced from associated software in homogenous phantom and heterogonous patient CT. Methods: IMRT and VMAT plans of five test suites introduced by TG119 were created in ECLIPSE on a solid water phantom. The ten plans -of increasing complexity- were delivered to Delta4 to give a 3D measurement. The Delta4's “Anatomy” software uses the measured dose to back-calculate the energy fluence of the delivered beams, which is used for dose calculation in a patient CT using a pencilbeam algorithm. The effect of the modulated beams' complexity on the accuracy of the “Anatomy” calculation was evaluated. Both measured and Anatomy doses were compared to ECLIPSE calculation using 3% - 3mm gamma criteria.We also tested the effect of heterogeneity by analyzing the results of “Anatomy” calculation on a Brain VMAT and a 3D conformal lung cases. Results: In homogenous phantom, the gamma passing rates were found to be as low as 74.75% for a complex plan with high modulation. The mean passing rates were 91.47% ± 6.35% for “Anatomy” calculation and 99.46% ± 0.62% for Delta4 measurements.As for the heterogeneous cases, the rates were 96.54%±3.67% and 83.87%±9.42% for Brain VMAT and 3D lung respectively. This increased error in the lung case could be due to the use of the pencil beam algorithm as opposed to the AAA used by ECLIPSE.Also, gamma analysis showed high discrepancy along the beam edge in the “Anatomy” calculated results. This suggests a poor beam modeling in the penumbra region. Conclusion: The results show various sources of errors in “Anatomy” calculations. These include beam modeling in the penumbra region, complexity of a modulated beam (shown in homogenous phantom and brain cases) and dose calculation algorithms (3D conformal lung case)

  1. Graph-cuts based reconstructing patient specific right ventricle: first human study.

    Science.gov (United States)

    Zhong, Liang; Wan, Min; Su, Yi; Teo, Soo Kng; Lim, Chi Wan; Zhao, Xiaodan; Zhang, Jun-Mei; Su, Bo Yang; Tan, Ju Le; Tan, Ru San

    2014-01-01

    Right ventricular (RV) function is increasingly recognized to play an important role in the clinical status and long-term outcome in patients with congenital heart disease as well as ischemic cardiomyopathy with left ventricular dysfunction. However, quantification of RV characteristics and function are still challenging due to its complex morphology and its thin wall with coarse trabeculations. To assess RV functions quantitatively, establishing the patient-specific model from medical images is a prerequisite task. This study aims to develop a novel method for RV model reconstruction. Magnetic resonance images were acquired and preprocessed. Contours of right ventricle, right atrium and pulmonary artery were manually delineated at all slices and all time frames. The contour coordinates as well as the medical image specifications such as image pixel resolution and slick thickness were exported. The contours were transformed to the correct positions. Reorientation and matching were executed in between neighboring contours; extrapolation and interpolation were conducted upon all contours. After preprocessing, the more dense point set was reconstructed through a variational tool. A Delaunay-based tetrahedral mesh was generated on the region of interest. The weighted minimal surface model was used to describe RV surface. The graphcuts technique, i.e., max-flow/min-cut algorithm, was applied to minimize the energy defined by the model. The reconstructed surface was extracted from the mesh according to the mincut. Smoothing and remeshing were performed. The CPU time to reconstruct the model for one frame was approximately 2 minutes. In 10 consecutive subjects referred for cardiac MRI (80% female), right ventricular volumes were measured using our method against the commercial available CMRtools package. The results demonstrated that there was a significant correlation in end-diastolic and end-systolic volumes between our method and commercial software (r= 0.89 for end

  2. A coverage probability based method to estimate patient-specific small bowel planning volumes for use in radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: The aim of this work was to develop a statistical method for generation of patient-specific planning organ-at-risk volumes (PRVs) for the small bowel (SB), by efficient use of a few repeat CT scans. Materials and methods: The PRVs are generated from a coverage probability (CP) matrix of the small bowel wall (SBW) by thresholding. To estimate the CPs, we extend a previously published 'relative frequency of coverage' approach by adding a 'soft margin' around each SBW instance. This prevents the CP matrix from containing any holes, thus making it more robust. As the number of CTs approach infinity, the 'soft margin' approaches zero and the CP matrix converges to the 'relative frequency of coverage'. The PRVs were evaluated by using the bootstrap method in three patients with different degrees of SB motion: The PRVs from randomly sampled subsets of CTs were compared to the PRVs generated from all 10-11 CT scans, by analysis of sensitivity and specificity. Furthermore, the PRVs generated for CP = 0.005 (i.e. generous patient-specific PRVs) and for CP = 0.03 (i.e. tight patient-specific PRVs) were compared to an intestinal cavity (IC) approach and a population based PRV approach of 10 and 30 mm isotropic planning margins around SB. Results: The sensitivity and specificity of the PRVs depend on the number of CT scans and the CP threshold. With three CT scans and a threshold of 0.03, an average sensitivity of 94-96% and specificity of 86-97% was obtained. All investigated SB planning volumes had an average overlap >89% of both SB and SBW. The tight patient-specific PRVs and the 10 mm margins had the lowest relative volumes, followed by the generous patient-specific PRVs, the 30 mm margins and the ICs. Conclusions: Based on a few CTs, our method generates patient-specific SB PRVs which are both sensitive and specific. Compared to conventional approaches, the patient-specific PRVs are either similar or better in predicting for SB voxels, and at the

  3. Development of cartilage conduction hearing aid

    Directory of Open Access Journals (Sweden)

    H. Hosoi

    2010-04-01

    Full Text Available Purpose: The potential demand for hearing aids is increasing in accordance with aging of populations in many developed countries. Because certain patients cannot use air conduction hearing aids, they usually use bone conduction hearing aids. However, bone does not transmit sound as efficiently as air, and bone conduction hearing aids require surgery (bone anchored hearing aid or great pressure to the skull. The first purpose of this study is to examine the efficacy of a new sound conduction pathway via the cartilage. The second purpose is to develop a hearing aid with a cartilage conduction transducer for patients who cannot use regular air conduction hearing aids.Design/methodology/approach: We examined the hearing ability of a patient with atresia of both external auditory meatuses via three kinds of conduction pathways (air, bone, and cartilage. After the best position for the cartilage conduction transducer was found, audiometric evaluation was performed for his left ear with an insertion earphone (air conduction, a bone conduction transducer, and a cartilage conduction transducer. Then we made a new hearing aid using cartilage conduction and got subjective data from the patients.Findings: The tragal cartilage was the best position for the cartilage conduction transducer. The patient’s mean hearing levels were 58.3 dBHL, 6.7 dBHL, and 3.3 dBHL for air conduction, bone conduction, and cartilage conduction respectively. The hearing ability of the patients obtained from the cartilage conduction hearing aid was comparable to those from the bone conduction hearing aid.Practical implications: Hearing levels using cartilage conduction are very similar to those via bone conduction. Cartilage conduction hearing aids may overcome the practical disadvantages of bone conduction hearing aids such as pain and the need for surgery.Originality/value: We have clarified the efficacy of the cartilage conduction pathway and developed a prototype

  4. A Finite Element Method to Predict Adverse Events in Intracranial Stenting Using Microstents: In Vitro Verification and Patient Specific Case Study.

    Science.gov (United States)

    Iannaccone, Francesco; De Beule, Matthieu; De Bock, Sander; Van der Bom, Imramsjah M J; Gounis, Matthew J; Wakhloo, Ajay K; Boone, Matthieu; Verhegghe, Benedict; Segers, Patrick

    2016-02-01

    Clinical studies have demonstrated the efficacy of stent supported coiling for intra-cranial aneurysm treatment. Despite encouraging outcomes, some matters are yet to be addressed. In particular closed stent designs are influenced by the delivery technique and may suffer from under-expansion, with the typical effect of "hugging" the inner curvature of the vessel which seems related to adverse events. In this study we propose a novel finite element (FE) environment to study potential failure able to reproduce the microcatheter "pull-back" delivery technique. We first verified our procedure with published in vitro data and then replicated the intervention on one patient treated with a 4.5 × 22 mm Enterprise microstent (Codman Neurovascular; Raynham MA, USA). Results showed good agreement with the in vitro test, catching both size and location of the malapposed area. A simulation of a 28 mm stent in the same geometry highlighted the impact of the delivery technique, which leads to larger area of malapposition. The patient specific simulation matched the global stent configuration and zones prone to malapposition shown on the clinical images with difference in tortuosity between actual and virtual treatment around 2.3%. We conclude that the presented FE strategy provides an accurate description of the stent mechanics and, after further in vivo validation and optimization, will be a tool to aid clinicians to anticipate the acute procedural outcome avoiding poor initial results. PMID:26620777

  5. [Orthognathic surgery: corrective bone operations].

    Science.gov (United States)

    Reuther, J

    2000-05-01

    The article reviews the history of orthognathic surgery from the middle of the last century up to the present. Initially, mandibular osteotomies were only performed in cases of severe malformations. But during the last century a precise and standardized procedure for correction of the mandible was established. Multiple modifications allowed control of small fragments, functionally stable osteosynthesis, and finally a precise positioning of the condyle. In 1955 Obwegeser and Trauner introduced the sagittal split osteotomy by an intraoral approach. It was the final breakthrough for orthognathic surgery as a standard treatment for corrections of the mandible. Surgery of the maxilla dates back to the nineteenth century. B. von Langenbeck from Berlin is said to have performed the first Le Fort I osteotomy in 1859. After minor changes, Wassmund corrected a posttraumatic malocclusion by a Le Fort I osteotomy in 1927. But it was Axhausen who risked the total mobilization of the maxilla in 1934. By additional modifications and further refinements, Obwegeser paved the way for this approach to become a standard procedure in maxillofacial surgery. Tessier mobilized the whole midface by a Le Fort III osteotomy and showed new perspectives in the correction of severe malformations of the facial bones, creating the basis of modern craniofacial surgery. While the last 150 years were distinguished by the creation and standardization of surgical methods, the present focus lies on precise treatment planning and the consideration of functional aspects of the whole stomatognathic system. To date, 3D visualization by CT scans, stereolithographic models, and computer-aided treatment planning and simulation allow surgery of complex cases and accurate predictions of soft tissue changes.

  6. Future perspectives in robotic surgery.

    Science.gov (United States)

    Wedmid, Alexei; Llukani, Elton; Lee, David I

    2011-09-01

    • Robotics of the current day have advanced significantly from early computer-aided design/manufacturing systems to modern master-slave robotic systems that replicate the surgeon's exact movements onto robotic instruments in the patient. • Globally >300,000 robotic procedures were completed in 2010, including ≈98,000 robot-assisted radical prostatectomies. • Broadening applications of robotics for urological procedures are being investigated in both adult and paediatric urology. • The use of the current robotic system continues to be further refined. Increasing experience has optimized port placement reducing arm collisions to allow for more expedient surgery. Improved three-dimensional camera magnification provides improved intraoperative identification of structures. • Robotics has probably improved the learning curve of laparoscopic surgery while still maintaining its patient recovery advantages and outcomes. • The future of robotic surgery will take this current platform forward by improving haptic (touch) feedback, improving vision beyond even the magnified eye, improving robot accessibility with a reduction of entry ports and miniaturizing the slave robot. • Here, we focus on the possible advancements that may change the future landscape of robotic surgery.

  7. Open heart surgery

    Science.gov (United States)

    Heart surgery - open ... lung machine is used in most cases during open heart surgery. While the surgeon works on the ... with these procedures, the surgeon may have to open the chest to do the surgery.

  8. Carotid artery surgery - discharge

    Science.gov (United States)

    ... Surgery, Society for Vascular Medicine, and Society for Vascular Surgery. J Am Coll Cardiol . 2011 Feb 22;57( ... 21288680 . Kinlay S, Bhatt DL. Treatment of noncoronary obstructive ... Textbook of Surgery . 19th ed. Elsevier Saunders; 2012:chap 63.

  9. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Soft Tissue Surgery Dental Implant Surgery Facial Cosmetic Surgery Head, Neck and Oral Pathology Obstructive Sleep Apnea TMJ and Facial Pain Treatment of Facial Injury Wisdom Teeth Management Procedures Administration of Anesthesia Administration of Anesthesia Oral ...

  10. Ear Plastic Surgery

    Science.gov (United States)

    ... receive light-weight earrings. Does Insurance Pay for Cosmetic Ear Surgery? Insurance usually does not cover surgery solely for ... republication strictly prohibited without prior written permission. Ears Cosmetic Surgery, Facelift, Rhinoplasty, Blepharoplasty ... Get Involved Professional Development Practice ...

  11. Laser surgery - skin

    Science.gov (United States)

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  12. Surgery for pancreatic cancer

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007649.htm Surgery for pancreatic cancer To use the sharing features on this page, ... surgery are used in the surgical treatment of pancreatic cancer. Whipple procedure: This is the most common surgery ...

  13. Single incision laparoscopic surgery

    Institute of Scientific and Technical Information of China (English)

    Arun; Prasad

    2010-01-01

    As a complement to standard laparoscopic surgery and a safe alternative to natural orifice transluminal endoscopic surgery,single incision laparoscopic surgery is gaining popularity.There are expensive ports,disposable hand instruments and flexible endoscopes that have been suggested to do this surgery and would increase the cost of operation.For a simple surgery like laparoscopic cholecystectomy,these extras are not needed and the surgery can be performed using standard ports,instruments and telescopes.Tri...

  14. Patient specific IMRT quality assurance with film, ionization chamber and detector arrays: Our institutional experience

    International Nuclear Information System (INIS)

    Purpose: This study was conducted to review patient specific IMRT QA delivered at our institution using Varian LINACs and TomoTherapy Hi-Art system and categorized according to the anatomical site, type of treatment machine, and treatment planning systems (TPS). Material and methods: Three thousand and three hundred seven patient data were evaluated for a time ranging from 2006 to 2011; these data were gauged using several methods used in the QA process. Ion chambers and film were used in 1738 patient plan QA in the earlier years followed by ion chamber arrays in 1569 patient plan QA in the latter years. Patients were grouped according to several parameters including TPS, site of treatment, and type of treatment machine in comparing the measured versus computed dose differences. From 2006 through early 2009, 736 TomoTherapy plans, 651 Pinnacle3 plans, and 351 Corvus plans were evaluated using ion chambers and films. The pass criterion at the institution at the time of these measurements was 3% dose difference and 3 mm distance to agreement. For the years ranging from 2009 to 2011, 1569 patient IMRT QAs were performed and evaluated on the institution's pass criteria of 90% γ value on Varian linacs with Millennium 80, 120 and High-Definition 120 multileaf collimators. Results: Average point dose difference between measured and calculated plans for Pinnacle3, Hi-ART TomoTherapy, and Corvus TPS were 0.1205%, −0.0042%, and −0.0178%. Among the QA plans measured using a 2D array, average gamma values for brain, head and neck, thorax, abdomen, and pelvis were 97.2%, 95.7%, 96.2%, 97.0%, and 96.2%, respectively. Average gamma values based on 80, 120, HD 120 and TomoTherapy MLC configurations were 96.5%, 96.2%, 96.3%, and 97%, respectively. A 2-tailed paired Student's T-test did not reveal the presence of statistically significant differences based on either TPS, anatomical sites, number of beams or arcs, number of control points, or the MLC configuration (p

  15. Cosmetic Plastic Surgery Statistics

    Science.gov (United States)

    2014 Cosmetic Plastic Surgery Statistics Cosmetic Procedure Trends 2014 Plastic Surgery Statistics Report Please credit the AMERICAN SOCIETY OF PLASTIC SURGEONS when citing statistical data or using ...

  16. Patient-specific prosthetic fingers by remote collaboration--a case study.

    Directory of Open Access Journals (Sweden)

    John-John Cabibihan

    Full Text Available The concealment of amputation through prosthesis usage can shield an amputee from social stigma and help improve the emotional healing process especially at the early stages of hand or finger loss. However, the traditional techniques in prosthesis fabrication defy this as the patients need numerous visits to the clinics for measurements, fitting and follow-ups. This paper presents a method for constructing a prosthetic finger through online collaboration with the designer. The main input from the amputee comes from the Computer Tomography (CT data in the region of the affected and the non-affected fingers. These data are sent over the internet and the prosthesis is constructed using visualization, computer-aided design and manufacturing tools. The finished product is then shipped to the patient. A case study with a single patient having an amputated ring finger at the proximal interphalangeal joint shows that the proposed method has a potential to address the patient's psychosocial concerns and minimize the exposure of the finger loss to the public.

  17. CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

    International Nuclear Information System (INIS)

    The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery

  18. CARS 2008: Computer Assisted Radiology and Surgery. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-06-15

    The proceedings contain contributions to the following topics: digital imaging, computed tomography, magnetic resonance, cardiac and vascular imaging, computer assisted radiation therapy, image processing and display, minimal invasive spinal surgery, computer assisted treatment of the prostate, the interventional radiology suite of the future, interventional oncology, computer assisted neurosurgery, computer assisted head and neck and ENT surgery, cardiovascular surgery, computer assisted orthopedic surgery, image processing and visualization, surgical robotics, instrumentation and navigation, surgical modelling, simulation and education, endoscopy and related techniques, workflow and new concepts in surgery, research training group 1126: intelligent surgery, digital operating room, image distribution and integration strategies, regional PACS and telemedicine, PACS - beyond radiology and E-learning, workflow and standardization, breast CAD, thoracic CAD, abdominal CAD, brain CAD, orthodontics, dentofacial orthopedics and airways, imaging and treating temporomandibular joint conditions, maxillofacial cone beam CT, craniomaxillofacial image fusion and CBCT incidental findings, image guided craniomaxillofacial procedures, imaging as a biomarker for therapy response, computer aided diagnosis. The Poster sessions cover the topics computer aided surgery, Euro PACS meeting, computer assisted radiology, computer aided diagnosis and computer assisted radiology and surgery.

  19. A patient-specific aperture system with an energy absorber for spot scanning proton beams: Verification for clinical application

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Keisuke, E-mail: k.yasui.20@west-med.jp [Nagoya Proton Therapy Center, Nagoya City West Medical Center, 1-1-1, Hirate-cho, Kita-ku, Nagoya-shi, Aichi-ken 462-8508, Japan and Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikouminami, Higashi-ku, Nagoya-shi, Aichi-ken 461-8673 (Japan); Toshito, Toshiyuki; Omachi, Chihiro; Kibe, Yoshiaki; Hayashi, Kensuke; Shibata, Hiroki; Tanaka, Kenichiro; Nikawa, Eiki; Asai, Kumiko; Shimomura, Akira; Kinou, Hideto; Isoyama, Shigeru; Mizoe, Jun-etsu [Nagoya Proton Therapy Center, Nagoya City West Medical Center, 1-1-1, Hirate-cho, Kita-ku, Nagoya-shi, Aichi-ken 462-8508 (Japan); Fujii, Yusuke; Takayanagi, Taisuke; Hirayama, Shusuke [Hitachi, Ltd., Hitachi Research Laboratory, 7-1-1, Omika-chou, Hitachi-shi, Ibaraki-ken 319-1292 (Japan); Nagamine, Yoshihiko [Hitachi, Ltd., Hitachi Works, 3-1-1, Saiwai-chou, Hitachi-shi, Ibaraki-ken 317-8511 (Japan); Shibamoto, Yuta [Graduate School of Medical Sciences, Nagoya City University, 1, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya-shi, Aichi-ken 467-8601 (Japan); Komori, Masataka [Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikouminami, Higashi-ku, Nagoya-shi, Aichi-ken 461-8673 (Japan)

    2015-12-15

    Purpose: In the authors’ proton therapy system, the patient-specific aperture can be attached to the nozzle of spot scanning beams to shape an irradiation field and reduce lateral fall-off. The authors herein verified this system for clinical application. Methods: The authors prepared four types of patient-specific aperture systems equipped with an energy absorber to irradiate shallow regions less than 4 g/cm{sup 2}. The aperture was made of 3-cm-thick brass and the maximum water equivalent penetration to be used with this system was estimated to be 15 g/cm{sup 2}. The authors measured in-air lateral profiles at the isocenter plane and integral depth doses with the energy absorber. All input data were obtained by the Monte Carlo calculation, and its parameters were tuned to reproduce measurements. The fluence of single spots in water was modeled as a triple Gaussian function and the dose distribution was calculated using a fluence dose model. The authors compared in-air and in-water lateral profiles and depth doses between calculations and measurements for various apertures of square, half, and U-shaped fields. The absolute doses and dose distributions with the aperture were then validated by patient-specific quality assurance. Measured data were obtained by various chambers and a 2D ion chamber detector array. Results: The patient-specific aperture reduced the penumbra from 30% to 70%, for example, from 34.0 to 23.6 mm and 18.8 to 5.6 mm. The calculated field width for square-shaped apertures agreed with measurements within 1 mm. Regarding patient-specific aperture plans, calculated and measured doses agreed within −0.06% ± 0.63% (mean ± SD) and 97.1% points passed the 2%-dose/2 mm-distance criteria of the γ-index on average. Conclusions: The patient-specific aperture system improved dose distributions, particularly in shallow-region plans.

  20. Aid and Development

    DEFF Research Database (Denmark)

    Tarp, Finn

    Foreign aid looms large in the public discourse; and international development assistance remains squarely on most policy agendas concerned with growth, poverty and inequality in Africa and elsewhere in the developing world. The present review takes a retrospective look at how foreign aid has...... evolved since World War II in response to a dramatically changing global political and economic context. I review the aid process and associated trends in the volume and distribution of aid and categorize some of the key goals, principles and institutions of the aid system. The evidence on whether aid has...... for aid in the future...

  1. Types of Foreign Aid

    DEFF Research Database (Denmark)

    Bjørnskov, Christian

    Foreign aid is given for many purposes and different intentions, yet most studies treat aid flows as a unitary concept. This paper uses factor analysis to separate aid flows into different types. The main types can be interpreted as aid for economic purposes, social purposes, and reconstruction......; a residual category captures remaining purposes. Estimating the growth effects of separable types of aid suggests that most aid has no effects while reconstruction aid has direct positive effects. Although this type only applies in special circumstances, it has become more prevalent in more recent years....

  2. Thinking about Aid Predictability

    OpenAIRE

    Andrews, Matthew; Wilhelm, Vera

    2008-01-01

    Researchers are giving more attention to aid predictability. In part, this is because of increases in the number of aid agencies and aid dollars and the growing complexity of the aid community. A growing body of research is examining key questions: Is aid unpredictable? What causes unpredictability? What can be done about it? This note draws from a selection of recent literature to bring s...

  3. Visual design and verification tool for collision-free dexterous patient specific neurosurgical instruments

    Science.gov (United States)

    Hess, Maggie; Eastwood, Kyle; Linder, Bence; Bodani, Vivek; Lasso, Andras; Looi, Thomas; Fichtinger, Gabor; Drake, James

    2016-03-01

    PURPOSE: In many minimally invasive neurosurgical procedures, the surgical workspace is a small tortuous cavity that is accessed using straight, rigid instruments with limited dexterity. Specifically considering neuroendoscopy, it is often challenging for surgeons, using standard instruments, to reach multiple surgical targets from a single incision. To address this problem, continuum tools are under development to create highly dexterous minimally invasive instruments. However, this design process is not trivial, and therefore, a user-friendly design platform capable of easily incorporating surgeon input is needed. METHODS: We propose a method that uses simulation and visual verification to design continuum tools that are patient and procedure specific. Our software module utilizes pre-operative scans and virtual threedimensional (3D) patient models to intuitively aid instrument design. The user specifies basic tool parameters and the parameterized tools and trocar are modeled within the virtual patient. By selecting and dragging the instrument models, the tools are instantly reshaped and repositioned. The tool geometry and surgical entry points are then returned as outputs to undergo optimization. We have completed an initial validation of the software by comparing a simulation of a physical instrument's reachability to the corresponding virtual design. RESULTS AND CONCLUSION: The software was assessed qualitatively by two neurosurgeons, who design tools for an intraventricular endoscopic procedure. Further, validation experiments comparing the design of a virtual instrument to a physical tool demonstrate that the software module functions correctly. Thus, our platform permits user-friendly, application specific design of continuum instruments. These instruments will give surgeons much more flexibility in developing future minimally invasive procedures.

  4. 3D active shape models of human brain structures: application to patient-specific mesh generation

    Science.gov (United States)

    Ravikumar, Nishant; Castro-Mateos, Isaac; Pozo, Jose M.; Frangi, Alejandro F.; Taylor, Zeike A.

    2015-03-01

    The use of biomechanics-based numerical simulations has attracted growing interest in recent years for computer-aided diagnosis and treatment planning. With this in mind, a method for automatic mesh generation of brain structures of interest, using statistical models of shape (SSM) and appearance (SAM), for personalised computational modelling is presented. SSMs are constructed as point distribution models (PDMs) while SAMs are trained using intensity profiles sampled from a training set of T1-weighted magnetic resonance images. The brain structures of interest are, the cortical surface (cerebrum, cerebellum & brainstem), lateral ventricles and falx-cerebri membrane. Two methods for establishing correspondences across the training set of shapes are investigated and compared (based on SSM quality): the Coherent Point Drift (CPD) point-set registration method and B-spline mesh-to-mesh registration method. The MNI-305 (Montreal Neurological Institute) average brain atlas is used to generate the template mesh, which is deformed and registered to each training case, to establish correspondence over the training set of shapes. 18 healthy patients' T1-weightedMRimages form the training set used to generate the SSM and SAM. Both model-training and model-fitting are performed over multiple brain structures simultaneously. Compactness and generalisation errors of the BSpline-SSM and CPD-SSM are evaluated and used to quantitatively compare the SSMs. Leave-one-out cross validation is used to evaluate SSM quality in terms of these measures. The mesh-based SSM is found to generalise better and is more compact, relative to the CPD-based SSM. Quality of the best-fit model instance from the trained SSMs, to test cases are evaluated using the Hausdorff distance (HD) and mean absolute surface distance (MASD) metrics.

  5. Development of an improved approach to radiation treatment therapy using high-definition patient-specific voxel phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Ward, R.C.; Ryman, J.C.; Worley, B.A.; Stallings, D.C. [Oak Ridge National Lab., TN (United States)

    1998-09-01

    Through an internally funded project at Oak Ridge National Laboratory, a high-resolution phantom was developed based on the National Library of Medicine`s Visible Human Data. Special software was written using the interactive data language (IDL) visualization language to automatically segment and classify some of the organs and the skeleton of the Visible Male. A high definition phantom consisting of nine hundred 512 x 512 slices was constructed of the entire torso. Computed tomography (CT) images of a patient`s tumor near the spine were scaled and morphed into the phantom model to create a patient-specific phantom. Calculations of dose to the tumor and surrounding tissue were then performed using the patient-specific phantom.

  6. How to Get Hearing Aids

    Science.gov (United States)

    ... Consumer Products Hearing Aids How to get Hearing Aids Share Tweet Linkedin Pin it More sharing options ... my hearing aids? How do I get hearing aids? To get hearing aids, you should first have ...

  7. SU-E-CAMPUS-T-04: Statistical Process Control for Patient-Specific QA in Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    LAH, J [Myongji Hospital, Goyangsi, Gyeonggi-do (Korea, Republic of); SHIN, D [National Cancer Center, Goyangsi, Gyeonggi-do (Korea, Republic of); Kim, G [UCSD Medical Center, La Jolla, CA (United States)

    2014-06-15

    Purpose: To evaluate and improve the reliability of proton QA process, to provide an optimal customized level using the statistical process control (SPC) methodology. The aim is then to suggest the suitable guidelines for patient-specific QA process. Methods: We investigated the constancy of the dose output and range to see whether it was within the tolerance level of daily QA process. This study analyzed the difference between the measured and calculated ranges along the central axis to suggest the suitable guidelines for patient-specific QA in proton beam by using process capability indices. In this study, patient QA plans were classified into 6 treatment sites: head and neck (41 cases), spinal cord (29 cases), lung (28 cases), liver (30 cases), pancreas (26 cases), and prostate (24 cases). Results: The deviations for the dose output and range of daily QA process were ±0.84% and ±019%, respectively. Our results show that the patient-specific range measurements are capable at a specification limit of ±2% in all treatment sites except spinal cord cases. In spinal cord cases, comparison of process capability indices (Cp, Cpm, Cpk ≥1, but Cpmk ≤1) indicated that the process is capable, but not centered, the process mean deviates from its target value. The UCL (upper control limit), CL (center line) and LCL (lower control limit) for spinal cord cases were 1.37%, −0.27% and −1.89%, respectively. On the other hands, the range differences in prostate cases were good agreement between calculated and measured values. The UCL, CL and LCL for prostate cases were 0.57%, −0.11% and −0.78%, respectively. Conclusion: SPC methodology has potential as a useful tool to customize an optimal tolerance levels and to suggest the suitable guidelines for patient-specific QA in clinical proton beam.

  8. Application of A Microstructural Constitutive Model of the Pulmonary Artery to Patient-Specific Studies: Validation and Effect of Orthotropy

    OpenAIRE

    Zhang, Yanhang; Dunn, Martin L.; Hunter, Kendall S.; Lanning, Craig; Ivy, D. Dunbar; Claussen, Lori; Chen, S. James; Shandas, Robin

    2007-01-01

    We applied a statistical mechanics based microstructural model of pulmonary artery mechanics, developed from our previous studies of rats with pulmonary arterial hypertension (PAH), to patient-specific clinical studies of children with PAH. Our previous animal studies provoked the hypothesis that increased cross-linking density of the molecular chains may be one biological remodeling mechanism by which the PA stiffens in PAH. This study appears to further confirm this hypothesis since varying...

  9. Abnormal Calcium Handling Properties Underlie Familial Hypertrophic Cardiomyopathy Pathology in Patient-Specific Induced Pluripotent Stem Cells

    OpenAIRE

    Lan, Feng; Lee, Andrew S.; Liang, Ping; Sanchez-Freire, Veronica; Nguyen, Patricia K; Wang, Li; Han, Leng; Yen, Michelle; Wang, Yongming; Sun, Ning; Abilez, Oscar J.; Hu, Shijun; Ebert, Antje D.; Navarrete, Enrique G.; Simmons, Chelsey S.

    2013-01-01

    Familial hypertrophic cardiomyopathy (HCM) is a prevalent hereditary cardiac disorder linked to arrhythmia and sudden cardiac death. While the causes of HCM have been identified as genetic mutations in the cardiac sarcomere, the pathways by which sarcomeric mutations engender myocyte hypertrophy and electrophysiological abnormalities are not understood. To elucidate the mechanisms underlying HCM development, we generated patient-specific induced pluripotent stem cell cardiomyocytes (iPSC-CMs)...

  10. Towards the Personalized Treatment of Glioblastoma: Integrating Patient-Specific Clinical Data in a Continuous Mechanical Model.

    Directory of Open Access Journals (Sweden)

    Maria Cristina Colombo

    Full Text Available Glioblastoma multiforme (GBM is the most aggressive and malignant among brain tumors. In addition to uncontrolled proliferation and genetic instability, GBM is characterized by a diffuse infiltration, developing long protrusions that penetrate deeply along the fibers of the white matter. These features, combined with the underestimation of the invading GBM area by available imaging techniques, make a definitive treatment of GBM particularly difficult. A multidisciplinary approach combining mathematical, clinical and radiological data has the potential to foster our understanding of GBM evolution in every single patient throughout his/her oncological history, in order to target therapeutic weapons in a patient-specific manner. In this work, we propose a continuous mechanical model and we perform numerical simulations of GBM invasion combining the main mechano-biological characteristics of GBM with the micro-structural information extracted from radiological images, i.e. by elaborating patient-specific Diffusion Tensor Imaging (DTI data. The numerical simulations highlight the influence of the different biological parameters on tumor progression and they demonstrate the fundamental importance of including anisotropic and heterogeneous patient-specific DTI data in order to obtain a more accurate prediction of GBM evolution. The results of the proposed mathematical model have the potential to provide a relevant benefit for clinicians involved in the treatment of this particularly aggressive disease and, more importantly, they might drive progress towards improving tumor control and patient's prognosis.

  11. Towards the Personalized Treatment of Glioblastoma: Integrating Patient-Specific Clinical Data in a Continuous Mechanical Model

    Science.gov (United States)

    Faggiano, Elena; Boffano, Carlo; Acerbi, Francesco; Ciarletta, Pasquale

    2015-01-01

    Glioblastoma multiforme (GBM) is the most aggressive and malignant among brain tumors. In addition to uncontrolled proliferation and genetic instability, GBM is characterized by a diffuse infiltration, developing long protrusions that penetrate deeply along the fibers of the white matter. These features, combined with the underestimation of the invading GBM area by available imaging techniques, make a definitive treatment of GBM particularly difficult. A multidisciplinary approach combining mathematical, clinical and radiological data has the potential to foster our understanding of GBM evolution in every single patient throughout his/her oncological history, in order to target therapeutic weapons in a patient-specific manner. In this work, we propose a continuous mechanical model and we perform numerical simulations of GBM invasion combining the main mechano-biological characteristics of GBM with the micro-structural information extracted from radiological images, i.e. by elaborating patient-specific Diffusion Tensor Imaging (DTI) data. The numerical simulations highlight the influence of the different biological parameters on tumor progression and they demonstrate the fundamental importance of including anisotropic and heterogeneous patient-specific DTI data in order to obtain a more accurate prediction of GBM evolution. The results of the proposed mathematical model have the potential to provide a relevant benefit for clinicians involved in the treatment of this particularly aggressive disease and, more importantly, they might drive progress towards improving tumor control and patient’s prognosis. PMID:26186462

  12. A patient-specific EMG-driven neuromuscular model for the potential use of human-inspired gait rehabilitation robots.

    Science.gov (United States)

    Ma, Ye; Xie, Shengquan; Zhang, Yanxin

    2016-03-01

    A patient-specific electromyography (EMG)-driven neuromuscular model (PENm) is developed for the potential use of human-inspired gait rehabilitation robots. The PENm is modified based on the current EMG-driven models by decreasing the calculation time and ensuring good prediction accuracy. To ensure the calculation efficiency, the PENm is simplified into two EMG channels around one joint with minimal physiological parameters. In addition, a dynamic computation model is developed to achieve real-time calculation. To ensure the calculation accuracy, patient-specific muscle kinematics information, such as the musculotendon lengths and the muscle moment arms during the entire gait cycle, are employed based on the patient-specific musculoskeletal model. Moreover, an improved force-length-velocity relationship is implemented to generate accurate muscle forces. Gait analysis data including kinematics, ground reaction forces, and raw EMG signals from six adolescents at three different speeds were used to evaluate the PENm. The simulation results show that the PENm has the potential to predict accurate joint moment in real-time. The design of advanced human-robot interaction control strategies and human-inspired gait rehabilitation robots can benefit from the application of the human internal state provided by the PENm.

  13. Design and Implementation of an On-Chip Patient-Specific Closed-Loop Seizure Onset and Termination Detection System.

    Science.gov (United States)

    Zhang, Chen; Bin Altaf, Muhammad Awais; Yoo, Jerald

    2016-07-01

    This paper presents the design of an area- and energy-efficient closed-loop machine learning-based patient-specific seizure onset and termination detection algorithm, and its on-chip hardware implementation. Application- and scenario-based tradeoffs are compared and reviewed for seizure detection and suppression algorithm and system which comprises electroencephalography (EEG) data acquisition, feature extraction, classification, and stimulation. Support vector machine achieves a good tradeoff among power, area, patient specificity, latency, and classification accuracy for long-term monitoring of patients with limited training seizure patterns. Design challenges of EEG data acquisition on a multichannel wearable environment for a patch-type sensor are also discussed in detail. Dual-detector architecture incorporates two area-efficient linear support vector machine classifiers along with a weight-and-average algorithm to target high sensitivity and good specificity at once. On-chip implementation issues for a patient-specific transcranial electrical stimulation are also discussed. The system design is verified using CHB-MIT EEG database [1] with a comprehensive measurement criteria which achieves high sensitivity and specificity of 95.1% and 96.2%, respectively, with a small latency of 1 s. It also achieves seizure onset and termination detection delay of 2.98 and 3.82 s, respectively, with seizure length estimation error of 4.07 s. PMID:27093712

  14. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Directory of Open Access Journals (Sweden)

    Arnau Benet

    2015-01-01

    Full Text Available Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens’ arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research.

  15. Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research

    Science.gov (United States)

    Benet, Arnau; Plata-Bello, Julio; Abla, Adib A.; Acevedo-Bolton, Gabriel; Saloner, David; Lawton, Michael T.

    2015-01-01

    Aim. To evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training. Methods. Two 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated. Results. The 3D aneurysm models were successfully implanted to the cadaveric specimens' arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation. Conclusion. 3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research. PMID:26539542

  16. A eletromiografia como auxílio na conduta terapêutica após cirurgia de craniotomia fronto-temporal: relato de caso Electromyography as an aid in therapeutic behavior after fronto-temporal craniotomy surgery: case report

    Directory of Open Access Journals (Sweden)

    Maristella Cecco Oncins

    2009-01-01

    insertion. After the surgery, the patient had dysfunction in temporal muscle and in temporo-mandibular joint, with reduction of the opening of mouth, pain while speaking and eating. Electromyography was used to quantitatively record the electrical activity of the temporal and masseter muscles in the initial evaluation and during the therapeutic process. Records were made at rest position, maximum occlusion and chew. They did miofuncional therapy throughout the process. RESULTS: examination data showed a significant increase in the electrical activity of the right anterior temporal muscle and a reduction in the activity of the left anterior temporal muscle. The initial Record showed a lower electrical activity on the right side compared to the left. With the miofunctional exercises there was a more effective participation of the right anterior temporal muscle, greater openness of mouth, without pain, making easier chewing and speech tasks, harmonizing the stomatognathic system. CONCLUSION: comparative records concerning electromyography in different stages of the therapeutic process helped and directed the best therapy, achieving a balance concerning the functions of breathing, sucking, chewing, swallowing and speech related to the stomatognathic system, considering the limitations of the case.

  17. Gastric bypass surgery

    Science.gov (United States)

    ... Roux-en-Y; Weight-loss surgery - gastric bypass; Obesity surgery - gastric bypass ... bypass surgery is not a quick fix for obesity. It will greatly change your lifestyle. After this surgery, you must eat healthy foods, control portion sizes of ...

  18. Combined Soft and Hard Tissue Peri-Implant Plastic Surgery Techniques to Enhance Implant Rehabilitation: A Case Report

    OpenAIRE

    Baltacıoğlu, Esra; Korkmaz, Fatih Mehmet; Bağış, Nilsun; Aydın, Güven; Yuva, Pınar; KORKMAZ, Yavuz Tolga; Bağış, Bora

    2014-01-01

    This case report presents an implant-aided prosthetic treatment in which peri-implant plastic surgery techniques were applied in combination to satisfactorily attain functional aesthetic expectations. Peri-implant plastic surgery enables the successful reconstruction and restoration of the balance between soft and hard tissues and allows the option of implant-aided fixed prosthetic rehabilitation.

  19. Robotic surgery is ready for prime time in India: Against the motion.

    Science.gov (United States)

    Udwadia, Tehemton E

    2015-01-01

    The use of Robotic Surgery as a purported adjunct and aid to Minimal Access Surgery (MAS) is growing in several areas. The acknowledged advantages as also the obvious and hidden disadvantages of Robotic Surgery are highlighted. Survey of literature shows that while Robotic Surgery is "feasible" and the results are "comparable" there is no convincing evidence that it is any better than MAS or even open surgery in most areas. To move "Robotic Surgery is ready for prime time in India" with no less than two dozen robots, many sub-optimally utilized for a population of 1.2 billion seems untenable. PMID:25598592

  20. Robotic surgery is ready for prime time in India: Against the motion

    Directory of Open Access Journals (Sweden)

    Tehemton E Udwadia

    2015-01-01

    Full Text Available The use of Robotic Surgery as a purported adjunct and aid to Minimal Access Surgery (MAS is growing in several areas. The acknowledged advantages as also the obvious and hidden disadvantages of Robotic Surgery are highlighted. Survey of literature shows that while Robotic Surgery is "feasible" and the results are "comparable" there is no convincing evidence that it is any better than MAS or even open surgery in most areas. To move "Robotic Surgery is ready for prime time in India" with no less than two dozen robots, many sub-optimally utilized for a population of 1.2 billion seems untenable.

  1. Aid and growth regressions

    DEFF Research Database (Denmark)

    Hansen, Henrik; Tarp, Finn

    2001-01-01

    This paper examines the relationship between foreign aid and growth in real GDP per capita as it emerges from simple augmentations of popular cross country growth specifications. It is shown that aid in all likelihood increases the growth rate, and this result is not conditional on ‘good’ policy....... There are, however, decreasing returns to aid, and the estimated effectiveness of aid is highly sensitive to the choice of estimator and the set of control variables. When investment and human capital are controlled for, no positive effect of aid is found. Yet, aid continues to impact on growth via...

  2. The use of patient-specific measurement instruments in the process of goal-setting: a systematic review of available instruments and their feasibility

    NARCIS (Netherlands)

    Stevens, A.; Beurskens, A.; Koke, A.; Weijden, T.T. van der

    2013-01-01

    OBJECTIVE: The aim of this study was to identify the currently available patient-specific measurement instruments used in the process of goal-setting and to assess their feasibility. METHODS: After a systematic search in PubMed, EMBASE, CINAHL, PsychINFO and REHABDATA, patient-specific instruments w

  3. How HIV Causes AIDS

    Science.gov (United States)

    ... Share this: Main Content Area How HIV Causes AIDS HIV destroys CD4 positive (CD4+) T cells, which ... and disease, ultimately resulting in the development of AIDS. Most people who are infected with HIV can ...

  4. HIV/AIDS Basics

    Science.gov (United States)

    ... Providers Prevention Resources Newsletter Get Tested Find an HIV testing site near you. Enter ZIP code or ... AIDS Get Email Updates on AAA Anonymous Feedback HIV/AIDS Media Infographics Syndicated Content Podcasts Slide Sets ...

  5. Aids for visual impairment.

    OpenAIRE

    Dudley, N. J.

    1990-01-01

    This article provides only a flavour of the type and range of aids available to the visually impaired person. Many other aids for leisure, learning, and daily living are illustrated in the RNIB equipment and games catalogue.

  6. Head injury - first aid

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000028.htm Head injury - first aid To use the sharing features on this page, ... a concussion can range from mild to severe. First Aid Learning to recognize a serious head injury and ...

  7. Poisoning first aid

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007579.htm Poisoning first aid To use the sharing features on this page, ... or burns Stupor Unconsciousness Unusual breath odor Weakness First Aid Seek immediate medical help. For poisoning by swallowing: ...

  8. Frostbite, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Frostbite, First Aid A A A Severe frostbite can result in ... became frozen). Frostbite is often associated with hypothermia. First Aid Guide In the case of mild frostbite, the ...

  9. Jellyfish Stings, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Jellyfish Stings, First Aid A A A The rash caused by a ... to Portuguese man-of-war stings as well. First Aid Guide The rescuer should take care to avoid ...

  10. Unconsciousness, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Unconsciousness, First Aid A A A Unconsciousness signs and symptoms can ... keep the airway clear while awaiting medical care. First Aid Guide If you find an unconscious person, try ...

  11. Tick Bites, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Tick Bites, First Aid A A A It is important to inspect ... temporary paralysis in their host (called tick paralysis). First Aid Guide To remove an embedded tick: Wash your ...

  12. Heat Cramps, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Cramps, First Aid A A A Heat cramp signs and symptoms ... if later stages of heat illness are suspected. First Aid Guide Use a combination of the following measures, ...

  13. Blisters, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Blisters, First Aid A A A Blisters on the feet are ... can also be found via the Disease List. First Aid Guide Blisters often go away on their own ...

  14. Heatstroke, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Heatstroke, First Aid A A A Heatstroke signs and symptoms can ... specific to the earlier stages of heat illness. First Aid Guide When heatstroke is suspected, seek emergency medical ...

  15. Heat Exhaustion, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Heat Exhaustion, First Aid A A A Heat exhaustion signs and symptoms ... specific to the other stages of heat illness. First Aid Guide Use a combination of the following measures ...

  16. First aid kit

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001958.htm First aid kit To use the sharing features on this ... ahead, you can create a well-stocked home first aid kit. Keep all of your supplies in one ...

  17. Head Trauma, First Aid

    Science.gov (United States)

    ... rashes clinical tools newsletter | contact Share | Head Trauma, First Aid A A A Head trauma signs and symptoms ... to take care for potential neck/spinal injury. First Aid Guide If you suspect either a serious head ...

  18. Bruises, First Aid

    Science.gov (United States)

    ... and rashes clinical tools newsletter | contact Share | Bruises, First Aid A A A Bruises lighten and change color ... Bruises can be a sign of internal bleeding. First Aid Guide If there is external bleeding in addition ...

  19. First Aid and Safety

    Science.gov (United States)

    ... Things to Know About Zika & Pregnancy First Aid & Safety Keeping your child safe is your top priority. ... to call for help, and more. First Aid & Safety Center Home Sweet Home A Safe and Spooktacular ...

  20. AIDS Myths and Misunderstandings

    Science.gov (United States)

    ... 2014 Select a Language: Fact Sheet 158 AIDS Myths and Misunderstandings WHY ARE THERE SO MANY AIDS ... sweat, saliva or urine of an infected person. Myth: A pregnant woman with HIV infection always infects ...

  1. First Aid: Influenza (Flu)

    Science.gov (United States)

    ... Smoothie Pregnant? Your Baby's Growth First Aid: The Flu KidsHealth > For Parents > First Aid: The Flu Print ... tiredness What to Do If Your Child Has Flu Symptoms: Call your doctor. Encourage rest. Keep your ...

  2. CARS 2009. Computer assisted radiology and surgery. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2009-06-15

    The CARS 2009 proceedings include contributions and poster sessions concerning different conferences and workshops: computer assisted radiology, 23rd international congress and exhibition, CARS clinical day, 13th annual conference of the international society for computer aided surgery, 10th CARS/SPIE/EuroPACS joint workshop on surgical PACS and the digital operating, 11th international workshop on computer-aided diagnosis, 15th computed maxillofacial imaging congress, CARS - computer assisted radiology and surgery, 1st EPMA/CARS workshop on personalized medicine and ICT, JICARS - Japanese institutes of CARS, 1st EuroNotes/CTAC/CARS workshop on NOTES: an interdisciplinary challenge, 13th annual conference for computer aided surgery, 27th international EuroPACS meeting.

  3. Music and Hearing Aids

    OpenAIRE

    Madsen, Sara M. K.; Moore, Brian C. J.

    2014-01-01

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems a...

  4. Fiscal effects of aid

    OpenAIRE

    Timmis, Emilija

    2015-01-01

    This thesis analyses fiscal effects of aid, first of health aid on health spending for a sample of developing countries and then broadly for Ethiopia and Tanzania. Particular attention is paid to data quality and the severe difficulties in achieving a reliable disaggregation of aid into its on-budget and off-budget components. The first essay assesses the sensitivity of estimated health aid fungibility to how the missing data (often considerable) are treated and explores a novel (at least in...

  5. Studying Aid: Some Methods

    OpenAIRE

    Gasper, Des

    2003-01-01

    textabstractINVESTIGATING IDEAS, IDEOLOGIES AND PRACTICES This paper presents some methods for trying to make sense of international aid and of its study.1 Some of the methods may be deemed ethnographic; the others are important partners to them, but rather different. In the course of discussing questions of aid policy and practice—such as: Should international development aid exist at all? How should aid be conducted? Should humanitarian relief be provided in conflict situations when it can ...

  6. Patient-specific radiation dose and cancer risk estimation in pediatric chest CT: a study in 30 patients

    Science.gov (United States)

    Li, Xiang; Samei, Ehsan; Segars, W. Paul; Sturgeon, Gregory M.; Colsher, James G.; Frush, Donald P.

    2010-04-01

    Radiation-dose awareness and optimization in CT can greatly benefit from a dosereporting system that provides radiation dose and cancer risk estimates specific to each patient and each CT examination. Recently, we reported a method for estimating patientspecific dose from pediatric chest CT. The purpose of this study is to extend that effort to patient-specific risk estimation and to a population of pediatric CT patients. Our study included thirty pediatric CT patients (16 males and 14 females; 0-16 years old), for whom full-body computer models were recently created based on the patients' clinical CT data. Using a validated Monte Carlo program, organ dose received by the thirty patients from a chest scan protocol (LightSpeed VCT, 120 kVp, 1.375 pitch, 40-mm collimation, pediatric body scan field-of-view) was simulated and used to estimate patient-specific effective dose. Risks of cancer incidence were calculated for radiosensitive organs using gender-, age-, and tissue-specific risk coefficients and were used to derive patientspecific effective risk. The thirty patients had normalized effective dose of 3.7-10.4 mSv/100 mAs and normalized effective risk of 0.5-5.8 cases/1000 exposed persons/100 mAs. Normalized lung dose and risk of lung cancer correlated strongly with average chest diameter (correlation coefficient: r = -0.98 to -0.99). Normalized effective risk also correlated strongly with average chest diameter (r = -0.97 to -0.98). These strong correlations can be used to estimate patient-specific dose and risk prior to or after an imaging study to potentially guide healthcare providers in justifying CT examinations and to guide individualized protocol design and optimization.

  7. Feasibility study of patient-specific quality assurance system for high-dose-rate brachytherapy in patients with cervical cancer

    Science.gov (United States)

    Lee, Boram; Ahn, Sung Hwan; Kim, Hyeyoung; Han, Youngyih; Huh, Seung Jae; Kim, Jin Sung; Kim, Dong Wook; Sim, Jina; Yoon, Myonggeun

    2016-04-01

    This study was conducted for the purpose of establishing a quality-assurance (QA) system for brachytherapy that can ensure patient-specific QA by enhancing dosimetric accuracy for the patient's therapy plan. To measure the point-absorbed dose and the 2D dose distribution for the patient's therapy plan, we fabricated a solid phantom that allowed for the insertion of an applicator for patient-specific QA and used an ion chamber and a film as measuring devices. The patient treatment plan was exported to the QA dose-calculation software, which calculated the time weight of dwell position stored in the plan DICOM (Digital Imaging and Communications in Medicine) file to obtain an overall beam quality correction factor, and that correction was applied to the dose calculations. Experiments were conducted after importing the patient's treatment planning source data for the fabricated phantom and inserting the applicator, ion chamber, and film into the phantom. On completion of dose delivery, the doses to the ion chamber and film were checked against the corresponding treatment plan to evaluate the dosimetric accuracy. For experimental purposes, five treatment plans were randomly selected. The beam quality correction factors for ovoid and tandem brachytherapy applicators were found to be 1.15 and 1.10 - 1.12, respectively. The beam quality correction factor in tandem fluctuated by approximately 2%, depending on the changes in the dwell position. The doses measured by using the ion chamber showed differences ranging from -2.4% to 0.6%, compared to the planned doses. As for the film, the passing rate was 90% or higher when assessed using a gamma value of the local dose difference of 3% and a distance to agreement of 3 mm. The results show that the self-fabricated phantom was suitable for QA in clinical settings. The proposed patient-specific QA for the treatment planning is expected to contribute to reduce dosimetric errors in brachytherapy and, thus, to enhancing treatment

  8. High-fidelity tissue engineering of patient-specific auricles for reconstruction of pediatric microtia and other auricular deformities.

    Directory of Open Access Journals (Sweden)

    Alyssa J Reiffel

    Full Text Available INTRODUCTION: Autologous techniques for the reconstruction of pediatric microtia often result in suboptimal aesthetic outcomes and morbidity at the costal cartilage donor site. We therefore sought to combine digital photogrammetry with CAD/CAM techniques to develop collagen type I hydrogel scaffolds and their respective molds that would precisely mimic the normal anatomy of the patient-specific external ear as well as recapitulate the complex biomechanical properties of native auricular elastic cartilage while avoiding the morbidity of traditional autologous reconstructions. METHODS: Three-dimensional structures of normal pediatric ears were digitized and converted to virtual solids for mold design. Image-based synthetic reconstructions of these ears were fabricated from collagen type I hydrogels. Half were seeded with bovine auricular chondrocytes. Cellular and acellular constructs were implanted subcutaneously in the dorsa of nude rats and harvested after 1 and 3 months. RESULTS: Gross inspection revealed that acellular implants had significantly decreased in size by 1 month. Cellular constructs retained their contour/projection from the animals' dorsa, even after 3 months. Post-harvest weight of cellular constructs was significantly greater than that of acellular constructs after 1 and 3 months. Safranin O-staining revealed that cellular constructs demonstrated evidence of a self-assembled perichondrial layer and copious neocartilage deposition. Verhoeff staining of 1 month cellular constructs revealed de novo elastic cartilage deposition, which was even more extensive and robust after 3 months. The equilibrium modulus and hydraulic permeability of cellular constructs were not significantly different from native bovine auricular cartilage after 3 months. CONCLUSIONS: We have developed high-fidelity, biocompatible, patient-specific tissue-engineered constructs for auricular reconstruction which largely mimic the native auricle both

  9. The feasibility of producing patient-specific acrylic cranioplasty implants with a low-cost 3D printer.

    Science.gov (United States)

    Tan, Eddie T W; Ling, Ji Min; Dinesh, Shree Kumar

    2016-05-01

    OBJECT Commercially available, preformed patient-specific cranioplasty implants are anatomically accurate but costly. Acrylic bone cement is a commonly used alternative. However, the manual shaping of the bone cement is difficult and may not lead to a satisfactory implant in some cases. The object of this study was to determine the feasibility of fabricating molds using a commercial low-cost 3D printer for the purpose of producing patient-specific acrylic cranioplasty implants. METHODS Using data from a high-resolution brain CT scan of a patient with a calvarial defect posthemicraniectomy, a skull phantom and a mold were generated with computer software and fabricated with the 3D printer using the fused deposition modeling method. The mold was used as a template to shape the acrylic implant, which was formed via a polymerization reaction. The resulting implant was fitted to the skull phantom and the cranial index of symmetry was determined. RESULTS The skull phantom and mold were successfully fabricated with the 3D printer. The application of acrylic bone cement to the mold was simple and straightforward. The resulting implant did not require further adjustment or drilling prior to being fitted to the skull phantom. The cranial index of symmetry was 96.2% (the cranial index of symmetry is 100% for a perfectly symmetrical skull). CONCLUSIONS This study showed that it is feasible to produce patient-specific acrylic cranioplasty implants with a low-cost 3D printer. Further studies are required to determine applicability in the clinical setting. This promising technique has the potential to bring personalized medicine to more patients around the world. PMID:26566203

  10. Determinants of State Aid

    NARCIS (Netherlands)

    Buiren, K.; Brouwer, E.

    2010-01-01

    From economic theory we derive a set of hypotheses on the determination of state aid. Econometric analysis on EU state aid panel data is carried out to test whether the determinants we expect on the basis of theory, correspond to the occurrence of state aid in practice in the EU. We find that politi

  11. First Aid: Falls

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Falls KidsHealth > For Parents > First Aid: Falls Print A A A Text Size en ... Floors, Doors & Windows, Furniture, Stairways: Household Safety Checklist First Aid: Broken Bones Head Injuries Preventing Children's Sports Injuries ...

  12. First Aid: Rashes

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Rashes KidsHealth > For Parents > First Aid: Rashes Print A A A Text Size Rashes ... For Kids For Parents MORE ON THIS TOPIC First Aid: Skin Infections Poison Ivy Erythema Multiforme Hives (Urticaria) ...

  13. First Aid: Dehydration

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Dehydration KidsHealth > For Parents > First Aid: Dehydration Print A A A Text Size Dehydration ... MORE ON THIS TOPIC Summer Safety Heat Illness First Aid: Heat Illness Sun Safety Dehydration Diarrhea Vomiting Word! ...

  14. First Aid: Burns

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Burns KidsHealth > For Parents > First Aid: Burns Print A A A Text Size Scald ... THIS TOPIC Kitchen: Household Safety Checklist Fireworks Safety First Aid: Sunburn Firesetting Fire Safety Burns Household Safety: Preventing ...

  15. First Aid: Choking

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Choking KidsHealth > For Parents > First Aid: Choking Print A A A Text Size Choking ... usually are taught as part of any basic first-aid course. Reviewed by: Steven Dowshen, MD Date reviewed: ...

  16. First Aid: Animal Bites

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Animal Bites KidsHealth > For Parents > First Aid: Animal Bites Print A A A Text Size ... For Kids For Parents MORE ON THIS TOPIC First Aid & Safety Center Infections That Pets Carry Dealing With ...

  17. First Aid: Croup

    Science.gov (United States)

    ... Story" 5 Things to Know About Zika & Pregnancy First Aid: Croup KidsHealth > For Parents > First Aid: Croup Print A A A Text Size Croup ... For Kids For Parents MORE ON THIS TOPIC First Aid: Coughing X-Ray Exam: Neck Why Is Hand ...

  18. Designing State Aid Formulas

    Science.gov (United States)

    Zhao, Bo; Bradbury, Katharine

    2009-01-01

    This paper designs a new equalization-aid formula based on fiscal gaps of local communities. When states are in transition to a new local aid formula, the issue of whether and how to hold existing aid harmless poses a challenge. The authors show that some previous studies and the formulas derived from them give differential weights to existing and…

  19. Correlation of phantom-based and log file patient-specific QA with complexity scores for VMAT.

    Science.gov (United States)

    Agnew, Christina E; Irvine, Denise M; McGarry, Conor K

    2014-11-08

    The motivation for this study was to reduce physics workload relating to patient- specific quality assurance (QA). VMAT plan delivery accuracy was determined from analysis of pre- and on-treatment trajectory log files and phantom-based ionization chamber array measurements. The correlation in this combination of measurements for patient-specific QA was investigated. The relationship between delivery errors and plan complexity was investigated as a potential method to further reduce patient-specific QA workload. Thirty VMAT plans from three treatment sites - prostate only, prostate and pelvic node (PPN), and head and neck (H&N) - were retrospectively analyzed in this work. The 2D fluence delivery reconstructed from pretreatment and on-treatment trajectory log files was compared with the planned fluence using gamma analysis. Pretreatment dose delivery verification was also car- ried out using gamma analysis of ionization chamber array measurements compared with calculated doses. Pearson correlations were used to explore any relationship between trajectory log file (pretreatment and on-treatment) and ionization chamber array gamma results (pretreatment). Plan complexity was assessed using the MU/ arc and the modulation complexity score (MCS), with Pearson correlations used to examine any relationships between complexity metrics and plan delivery accu- racy. Trajectory log files were also used to further explore the accuracy of MLC and gantry positions. Pretreatment 1%/1 mm gamma passing rates for trajectory log file analysis were 99.1% (98.7%-99.2%), 99.3% (99.1%-99.5%), and 98.4% (97.3%-98.8%) (median (IQR)) for prostate, PPN, and H&N, respectively, and were significantly correlated to on-treatment trajectory log file gamma results (R = 0.989, p log file gamma results (R = 0.623, p 0.57, p log file fluence delivery and ionization chamber array measurements were strongly correlated with on-treatment trajectory log file fluence delivery. The strong corre- lation

  20. Generation of patient-specific pluripotent stem cells and directed differentiation of embryonic stem cells for regenerative medicine

    Institute of Scientific and Technical Information of China (English)

    Minyue Ma; Jiahao Sha; Zuomin Zhou; Qi Zhou; Qingzhang Li

    2008-01-01

    Embryonic stem(ES) cells are pluripotent cells that can give rise to derivatives of all three embryonic germ layers. Due to its characteristics, the patient-specific ES cells are of great potential for transplantation therapies. Several strategies can reprogramme somatic cells back to pluripotent stem cells: nuclear transfer, fusion with ES cells, treatment with cell extract and induction by specific factors. Considering the future clinical use, the differentiation from ES to neurons, cardiomyocytes and many other types of cell scurrently provide basic cognition and experience to regenerative medicine. This article will review two courses, the reprogramming of differentiated cells and the differentiation of ES cells to specific cell types.

  1. Review of the neuromonitoring in thyroid surgery

    Directory of Open Access Journals (Sweden)

    Pardal-Refoyo JL

    2012-04-01

    Full Text Available Introduction and Objectives: The identification of recurrent laryngeal nerve (RLN during thyroid surgery is considered gold standard to prevent their injury. Electromyographic recordings of the thyroarytenoid muscle activity after electrical stimulation of the vagus or RLN nerves aid during identification of the RLN and reports of their functional status at the end of thyroidectomy. For the record electromyographic two are the most useful techniques: using surface electrodes on the endotracheal tube (ETT and by needle electrodes inserted into the thyroarytenoid muscles across the cricothyroid membrane (transligamentary technique, TL. Objectives: To review the methods of identification of the RLN in thyroid surgery, the main techniques for neuromonitoring, their validity and summarize practical technical details.Conclusions: The neuromonitoring aid in the location, identification and dissection the RLN, aid in decision-making when there is loss of the electromyographic signal and provides information about the function of NLR at the end of surgery. The neuromonitoring has benefits in clinical practice, research, in teaching and in medical-legal.

  2. Dental outcomes in computer-assisted orthognathic surgery.

    Science.gov (United States)

    Hamilton, Travis; Markiewicz, Michael R; Jarman, Joseph; Bell, R Bryan

    2012-05-01

    The purpose of this study was to assess the effectiveness of computer-aided orthognathic surgery in reducing incisal overjet and establishing class I occlusion in subjects with dentofacial deformities. To address the research purpose, the investigators initiated a retrospective cohort study and enrolled a sample of subjects who underwent computer-assisted orthognathic surgery for dentofacial deformities. Two examiners assessed preoperative and postoperative lateral cephalometric radiographs for change in overjet after computer-assisted orthognathic surgery. Preoperative and postoperative occlusal photographs were then reviewed to assess for establishment of class I occlusion after computer-assisted orthognathic surgery. Cohen κ coefficient was used to assess for interrater agreement. A matched-pairs t-test was used to assess reduction in incisal overjet after computer-assisted orthognathic surgery. The sample was composed of 9 subjects who underwent computer-assisted surgery for dentofacial deformities. There was good interrater consistency for preoperative measurement of overjet (κ = 0.7, P ≤ 0.001). There was fair interrater consistency for postoperative measurement of overjet (κ = 0.4, P = 0 .02). Both examiners agreed on preoperative and postoperative assessments of occlusal photographs. There was a 3.4-mm reduction in incisal overjet after computer-assisted orthognathic surgery (P ≤ 0.001). Mean postoperative absolute overjet was 1.3 mm. In subjects with dentofacial deformities, computer-aided orthognathic surgery was effective in reducing incisal overjet and establishing class I occlusion.

  3. Models for Planning and Simulation in Computer Assisted Orthognatic Surgery

    CERN Document Server

    Chabanas, M; Payan, Y; Boutault, F; Chabanas, Matthieu; Marecaux, Christophe; Payan, Yohan; Boutault, Franck

    2002-01-01

    Two aspects required to establish a planning in orthognatic surgery are addressed in this paper. First, a 3D cephalometric analysis, which is clini-cally essential for the therapeutic decision. Then, an original method to build a biomechanical model of patient face soft tissue, which provides evaluation of the aesthetic outcomes of an intervention. Both points are developed within a clinical application context for computer aided maxillofacial surgery.

  4. Why foreign aid fails

    Directory of Open Access Journals (Sweden)

    Prokopijević Miroslav

    2007-01-01

    Full Text Available The main point of this paper is that foreign aid fails because the structure of its incentives resembles that of central planning. Aid is not only ineffective, it is arguably counterproductive. Contrary to business firms that are paid by those they are supposed to serve (customers, aid agencies are paid by tax payers of developed countries and not by those they serve. This inverse structure of incentives breaks the stream of pressure that exists on the commercial market. It also creates larger loopholes in the principle-agent relationship on each point along the chain of aid delivery. Both factors enhance corruption, moral hazard and negative selection. Instead of promoting development, aid extends the life of bad institutions and those in power. Proposals to reform foreign aid – like aid privatization and aid conditionality – do not change the existing structure of the incentives in aid delivery, and their implementation may just slightly improve aid efficacy. Larger improvement is not possible. For that reason, foreign aid will continue to be a waste of resources, probably serving some objectives different to those that are usually mentioned, like recipient’s development poverty reduction and pain relief.

  5. Orthodontic-orthognathic interventions in orthognathic surgical cases: "Paper surgery" and "model surgery" concepts in surgical orthodontics.

    Science.gov (United States)

    Gandedkar, Narayan H; Chng, Chai Kiat; Yeow, Vincent Kok Leng

    2016-01-01

    Thorough planning and execution is the key for successful treatment of dentofacial deformity involving surgical orthodontics. Presurgical planning (paper surgery and model surgery) are the most essential prerequisites of orthognathic surgery, and orthodontist is the one who carries out this procedure by evaluating diagnostic aids such as crucial clinical findings and radiographic assessments. However, literature pertaining to step-by-step orthognathic surgical guidelines is limited. Hence, this article makes an attempt to provide an insight and nuances involved in the planning and execution. The diagnostic information revealed from clinical findings and radiographic assessments is integrated in the "paper surgery" to establish "surgical-plan." Furthermore, the "paper surgery" is emulated in "model surgery" such that surgical bite-wafers are created, which aid surgeon to preview the final outcome and make surgical movements that are deemed essential for the desired skeletal and dental outcomes. Skeletal complexities are corrected by performing "paper surgery" and an occlusion is set up during "model surgery" for the fabrication of surgical bite-wafers. Further, orthodontics is carried out for the proper settling and finishing of occlusion. Article describes the nuances involved in the treatment of Class III skeletal deformity individuals treated with orthognathic surgical approach and illustrates orthodontic-orthognathic step-by-step procedures from "treatment planning" to "execution" for successful management of aforementioned dentofacial deformity. PMID:27630506

  6. Orthodontic-orthognathic interventions in orthognathic surgical cases: "Paper surgery" and "model surgery" concepts in surgical orthodontics

    Directory of Open Access Journals (Sweden)

    Narayan H Gandedkar

    2016-01-01

    Full Text Available Thorough planning and execution is the key for successful treatment of dentofacial deformity involving surgical orthodontics. Presurgical planning (paper surgery and model surgery are the most essential prerequisites of orthognathic surgery, and orthodontist is the one who carries out this procedure by evaluating diagnostic aids such as crucial clinical findings and radiographic assessments. However, literature pertaining to step-by-step orthognathic surgical guidelines is limited. Hence, this article makes an attempt to provide an insight and nuances involved in the planning and execution. The diagnostic information revealed from clinical findings and radiographic assessments is integrated in the "paper surgery" to establish "surgical-plan." Furthermore, the "paper surgery" is emulated in "model surgery" such that surgical bite-wafers are created, which aid surgeon to preview the final outcome and make surgical movements that are deemed essential for the desired skeletal and dental outcomes. Skeletal complexities are corrected by performing "paper surgery" and an occlusion is set up during "model surgery" for the fabrication of surgical bite-wafers. Further, orthodontics is carried out for the proper settling and finishing of occlusion. Article describes the nuances involved in the treatment of Class III skeletal deformity individuals treated with orthognathic surgical approach and illustrates orthodontic-orthognathic step-by-step procedures from "treatment planning" to "execution" for successful management of aforementioned dentofacial deformity.

  7. Orthodontic-orthognathic interventions in orthognathic surgical cases: "Paper surgery" and "model surgery" concepts in surgical orthodontics.

    Science.gov (United States)

    Gandedkar, Narayan H; Chng, Chai Kiat; Yeow, Vincent Kok Leng

    2016-01-01

    Thorough planning and execution is the key for successful treatment of dentofacial deformity involving surgical orthodontics. Presurgical planning (paper surgery and model surgery) are the most essential prerequisites of orthognathic surgery, and orthodontist is the one who carries out this procedure by evaluating diagnostic aids such as crucial clinical findings and radiographic assessments. However, literature pertaining to step-by-step orthognathic surgical guidelines is limited. Hence, this article makes an attempt to provide an insight and nuances involved in the planning and execution. The diagnostic information revealed from clinical findings and radiographic assessments is integrated in the "paper surgery" to establish "surgical-plan." Furthermore, the "paper surgery" is emulated in "model surgery" such that surgical bite-wafers are created, which aid surgeon to preview the final outcome and make surgical movements that are deemed essential for the desired skeletal and dental outcomes. Skeletal complexities are corrected by performing "paper surgery" and an occlusion is set up during "model surgery" for the fabrication of surgical bite-wafers. Further, orthodontics is carried out for the proper settling and finishing of occlusion. Article describes the nuances involved in the treatment of Class III skeletal deformity individuals treated with orthognathic surgical approach and illustrates orthodontic-orthognathic step-by-step procedures from "treatment planning" to "execution" for successful management of aforementioned dentofacial deformity.

  8. Aid and development

    DEFF Research Database (Denmark)

    Tarp, Finn

    2006-01-01

    Foreign aid looms large in the public discourse; and international development assistance remains squarely on most policy agendas concerned with growth, poverty and inequality in Africa and elsewhere in the developing world. The present review takes a retrospective look at how foreign aid has...... evolved since World War II in response to a dramatically changing global political and economic context. I review the aid process and associated trends in the volume and distribution of aid and categorize some of the key goals, principles and institutions of the aid system. The evidence on whether aid has...... been effective in furthering economic growth and development is discussed in some detail. I add perspective and identify some critical unresolved issues. I finally turn to the current development debate and discuss some key concerns, I believe should be kept in mind in formulating any agenda for aid...

  9. Conditional Aid Effectiveness

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL (aid effectiveness literature) studies the effect of development aid using econometrics on macro data. It contains about 100 papers of which a third analyzes conditional models where aid effectiveness depends upon z, so that aid only works for a certain range of the variable. The key term...... in this family of AEL models is thus an interaction term of z times aid. The leading candidates for z are a good policy index and aid itself. In this paper, meta-analysis techniques are used (i) to determine whether the AEL has established the said interaction terms, and (ii) to identify some of the determinants...... of the differences in results between studies. Taking all available studies in consideration, we find no support for conditionality with respect to policy, while conditionality regarding aid itself is dubious. However, the results differ depending on the authors’ institutional affiliation....

  10. China vs. AIDS

    Institute of Scientific and Technical Information of China (English)

    LURUCAI

    2004-01-01

    CHINA's first HIV positive diagnosis was in 1985, the victim an ArgentineAmerican. At that time most Chinese,medical workers included, thought of AIDS as a phenomenon occurring outside of China. Twenty years later, the number of HIV/AIDS patients has risen alarmingly. In 2003, the Chinese Ministry of Health launched an AIDS Epidemiological Investigation across China with the support of the WHO and UN AIDS Program. Its results show that there are currently 840,000 HIV carriers, including 80,000 people with full-blown AIDS, in 31 Chinese provinces, municipalities and autonomous regions. This means China has the second highest number of HIV/AIDS cases in Asia and 14th highest in the world. Statistics from the Chinese Venereal Disease and AIDS Prevention Association indicate that the majority of Chinese HIV carriers are young to middle aged, more than half of them between the ages of 20 and 29.

  11. Aid and Development

    DEFF Research Database (Denmark)

    Tarp, Finn; Arndt, Channing; Jones, Edward Samuel

    This paper considers the relationship between external aid and development in Mozambique from 1980 to 2004. The main objective is to identify the specific mechanisms through which aid has influenced the developmental trajectory of the country and whether one can plausibly link outcomes to aid...... inputs. We take as our point of departure a growth accounting analysis and review both intended and unintended effects of aid. Mozambique has benefited from sustained aid inflows in conflict, post-conflict and reconstruction periods. In each of these phases aid has made an unambiguous, positive...... contribution both enabling and supporting rapid growth since 1992. At the same time, the proliferation of donors and aid-supported interventions has burdened local administration and there is a distinct need to develop government accountability to its own citizens rather than donor agencies. In ensuring...

  12. MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, W; Swann, B; Siderits, R; McKenna, M; Khan, A; Yue, N; Zhang, M [Rutgers University, New Brunswick, NJ (United States); Fisher, T [Memorial Medical Center, Modesto, CA (United States)

    2014-06-15

    Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice.

  13. MO-H-19A-03: Patient Specific Bolus with 3D Printing Technology for Electron Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: Bolus is widely used in electron radiotherapy to achieve desired dose distribution. 3D printing technologies provide clinicians with easy access to fabricate patient specific bolus accommodating patient body surface irregularities and tissue inhomogeneity. This study presents the design and the clinical workflow of 3D printed bolus for patient electron therapy in our clinic. Methods: Patient simulation CT images free of bolus were exported from treatment planning system (TPS) to an in-house developed software package. Bolus with known material properties was designed in the software package and then exported back to the TPS as a structure. Dose calculation was carried out to examine the coverage of the target. After satisfying dose distribution was achieved, the bolus structure was transferred in Standard Tessellation Language (STL) file format for the 3D printer to generate the machine codes for printing. Upon receiving printed bolus, a quick quality assurance was performed with patient resimulated with bolus in place to verify the bolus dosimetric property before treatment started. Results: A patient specific bolus for electron radiotherapy was designed and fabricated in Form 1 3D printer with methacrylate photopolymer resin. Satisfying dose distribution was achieved in patient with bolus setup. Treatment was successfully finished for one patient with the 3D printed bolus. Conclusion: The electron bolus fabrication with 3D printing technology was successfully implemented in clinic practice

  14. Use of 3D printers to create a patient-specific 3D bolus for external beam therapy.

    Science.gov (United States)

    Burleson, Sarah; Baker, Jamie; Hsia, An Ting; Xu, Zhigang

    2015-01-01

    The purpose of this paper is to demonstrate that an inexpensive 3D printer can be used to manufacture patient-specific bolus for external beam therapy, and to show we can accurately model this printed bolus in our treatment planning system for accurate treatment delivery. Percent depth-dose measurements and tissue maximum ratios were used to determine the characteristics of the printing materials, acrylonitrile butadiene styrene and polylactic acid, as bolus material with physical density of 1.04 and 1.2 g/cm3, and electron density of 3.38 × 10²³ electrons/cm3 and 3.80 × 10²³ electrons/ cm3, respectively. Dose plane comparisons using Gafchromic EBT2 film and the RANDO phantom were used to verify accurate treatment planning. We accurately modeled a printing material in Eclipse treatment planning system, assigning it a Hounsfield unit of 260. We were also able to verify accurate treatment planning using gamma analysis for dose plane comparisons. With gamma criteria of 5% dose difference and 2 mm DTA, we were able to have 86.5% points passing, and with gamma criteria of 5% dose difference and 3 mm DTA, we were able to have 95% points passing. We were able to create a patient-specific bolus using an inexpensive 3D printer and model it in our treatment planning system for accurate treatment delivery. PMID:26103485

  15. Patient-specific cardiovascular progenitor cells derived from integration-free induced pluripotent stem cells for vascular tissue regeneration.

    Science.gov (United States)

    Hu, Jiang; Wang, Yongyu; Jiao, Jiao; Liu, Zhongning; Zhao, Chao; Zhou, Zhou; Zhang, Zhanpeng; Forde, Kaitlynn; Wang, Lunchang; Wang, Jiangang; Baylink, David J; Zhang, Xiao-Bing; Gao, Shaorong; Yang, Bo; Chen, Y Eugene; Ma, Peter X

    2015-12-01

    Tissue-engineered blood vessels (TEBVs) are promising in regenerating a live vascular replacement. However, the vascular cell source is limited, and it is crucial to develop a scaffold that accommodates new type of vascular progenitor cells and facilitates in vivo lineage specification of the cells into functional vascular smooth muscle cells (VSMCs) to regenerate vascular tissue. In the present study, integration-free human induced pluripotent stem cells (hiPSCs) were established from patient peripheral blood mononuclear cells through episomal vector nucleofection of reprogramming factors. The established hiPSCs were then induced into mesoderm-originated cardiovascular progenitor cells (CVPCs) with a highly efficient directed lineage specification method. The derived CVPCs were demonstrated to be able to differentiate into functional VSMCs. Subcutaneous implantation of CVPCs seeded on macroporous nanofibrous poly(l-lactide) scaffolds led to in vivo VSMC lineage specification and matrix deposition inside the scaffolds. In summary, we established integration-free patient-specific hiPSCs from peripheral blood mononuclear cells, derived CVPCs through directed lineage specification, and developed an advanced scaffold for these progenitor cells to further differentiate in vivo into VSMCs and regenerate vascular tissue in a subcutaneous implantation model. This study has established an efficient patient-specific approach towards in vivo regeneration of vascular tissue.

  16. High-quality conforming hexahedral meshes of patient-specific abdominal aortic aneurysms including their intraluminal thrombi.

    Science.gov (United States)

    Tarjuelo-Gutierrez, J; Rodriguez-Vila, B; Pierce, D M; Fastl, T E; Verbrugghe, P; Fourneau, I; Maleux, G; Herijgers, P; Holzapfel, G A; Gomez, E J

    2014-02-01

    In order to perform finite element (FE) analyses of patient-specific abdominal aortic aneurysms, geometries derived from medical images must be meshed with suitable elements. We propose a semi-automatic method for generating conforming hexahedral meshes directly from contours segmented from medical images. Magnetic resonance images are generated using a protocol developed to give the abdominal aorta high contrast against the surrounding soft tissue. These data allow us to distinguish between the different structures of interest. We build novel quadrilateral meshes for each surface of the sectioned geometry and generate conforming hexahedral meshes by combining the quadrilateral meshes. The three-layered morphology of both the arterial wall and thrombus is incorporated using parameters determined from experiments. We demonstrate the quality of our patient-specific meshes using the element Scaled Jacobian. The method efficiently generates high-quality elements suitable for FE analysis, even in the bifurcation region of the aorta into the iliac arteries. For example, hexahedral meshes of up to 125,000 elements are generated in less than 130 s, with 94.8 % of elements well suited for FE analysis. We provide novel input for simulations by independently meshing both the arterial wall and intraluminal thrombus of the aneurysm, and their respective layered morphologies.

  17. cGMP production of patient-specific iPSCs and photoreceptor precursor cells to treat retinal degenerative blindness.

    Science.gov (United States)

    Wiley, Luke A; Burnight, Erin R; DeLuca, Adam P; Anfinson, Kristin R; Cranston, Cathryn M; Kaalberg, Emily E; Penticoff, Jessica A; Affatigato, Louisa M; Mullins, Robert F; Stone, Edwin M; Tucker, Budd A

    2016-01-01

    Immunologically-matched, induced pluripotent stem cell (iPSC)-derived photoreceptor precursor cells have the potential to restore vision to patients with retinal degenerative diseases like retinitis pigmentosa. The purpose of this study was to develop clinically-compatible methods for manufacturing photoreceptor precursor cells from adult skin in a non-profit cGMP environment. Biopsies were obtained from 35 adult patients with inherited retinal degeneration and fibroblast lines were established under ISO class 5 cGMP conditions. Patient-specific iPSCs were then generated, clonally expanded and validated. Post-mitotic photoreceptor precursor cells were generated using a stepwise cGMP-compliant 3D differentiation protocol. The recapitulation of the enhanced S-cone phenotype in retinal organoids generated from a patient with NR2E3 mutations demonstrated the fidelity of these protocols. Transplantation into immune compromised animals revealed no evidence of abnormal proliferation or tumor formation. These studies will enable clinical trials to test the safety and efficiency of patient-specific photoreceptor cell replacement in humans. PMID:27471043

  18. Future of liver transplantation: Non-human primates for patient-specific organs from induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    Madhusudana Girija Sanal

    2011-01-01

    Strategies to fill the huge gap in supply versus demand of human organs include bioartificial organs, growing humanized organs in animals, cell therapy, and im-plantable bioengineered constructs. Reproducing the complex relations between different cell types, gen-eration of adequate vasculature, and immunological complications are road blocks in generation of bioengi-neered organs, while immunological complications limit the use of humanized organs produced in animals. Recent developments in induced pluripotent stem cell (iPSC) biology offer a possibility of generating human, patient-specific organs in non-human primates (NHP) using patient-derived iPSC and NHP-derived iPSC lack-ing the critical developmental genes for the organ of interest complementing a NHP tetraploid embryo. The organ derived in this way will have the same human leukocyte antigen (HLA) profile as the patient. This ap-proach can be curative in genetic disorders as this of-fers the possibility of gene manipulation and correction of the patient's genome at the iPSC stage before tet-raploid complementation. The process of generation of patient-specific organs such as the liver in this way has the great advantage of making use of the natural sig-naling cascades in the natural milieu probably resulting in organs of great quality for transplantation. However, the inexorable scientific developments in this direction involve several social issues and hence we need to educate and prepare society in advance to accept the revolutionary consequences, good, bad and ugly.

  19. Weight Loss Surgery

    Science.gov (United States)

    Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you ... caused by obesity. There are different types of weight loss surgery. They often limit the amount of food ...

  20. Spine surgery - discharge

    Science.gov (United States)

    ... Vertebral interbody fusion - discharge; Posterior spinal fusion - discharge; Arthrodesis - discharge; Anterior spinal fusion - discharge; Spine surgery - spinal fusion - discharge Images Spinal surgery -- cervical - series References Agrawal BM, Zeidman SM, Rhines L, ...

  1. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... best performed by a trained surgeon with specialized education and training. Click here to find out more. Facial Cosmetic Surgery Facial Cosmetic Surgery Extensive education and training in surgical procedures involving skin, muscle, ...

  2. Refractive corneal surgery - discharge

    Science.gov (United States)

    ... after surgery, it should be okay to use artificial tears. Check with your doctor. Do NOT wear contact lenses on the eye that had surgery, even if you have blurry vision. Do NOT use any makeup, creams, or lotions ...

  3. Bariatric Surgery Misconceptions

    Science.gov (United States)

    ... from depression or anxiety and to have lower self-esteem and overall quality of life than someone who ... is a Candidate for Bariatric Surgery? Childhood and Adolescent Obesity Find a Provider Benefits of Bariatric Surgery ...

  4. Cosmetic ear surgery

    Science.gov (United States)

    Otoplasty; Ear pinning; Ear surgery - cosmetic; Ear reshaping; Pinnaplasty ... Cosmetic ear surgery may be done in the surgeon's office, an outpatient clinic, or a hospital. It can be performed under ...

  5. Hip fracture surgery

    Science.gov (United States)

    ... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis-hip ... You may receive general anesthesia before this surgery. This means ... spinal anesthesia. With this kind of anesthesia, medicine is ...

  6. Coronary Artery Bypass Surgery

    Science.gov (United States)

    ... don't help, you may need coronary artery bypass surgery. The surgery creates a new path for ... narrowed area or blockage. This allows blood to bypass (get around) the blockage. Sometimes people need more ...

  7. Robotic liver surgery.

    Science.gov (United States)

    Leung, Universe; Fong, Yuman

    2014-10-01

    Robotic surgery is an evolving technology that has been successfully applied to a number of surgical specialties, but its use in liver surgery has so far been limited. In this review article we discuss the challenges of minimally invasive liver surgery, the pros and cons of robotics, the evolution of medical robots, and the potentials in applying this technology to liver surgery. The current data in the literature are also presented. PMID:25392840

  8. Development of plastic surgery

    OpenAIRE

    Pećanac Marija Đ.

    2015-01-01

    Introduction. Plastic surgery is a medical specialty dealing with corrections of defects, improvements in appearance and restoration of lost function. Ancient Times. The first recorded account of reconstructive plastic surgery was found in ancient Indian Sanskrit texts, which described reconstructive surgeries of the nose and ears. In ancient Greece and Rome, many medicine men performed simple plastic cosmetic surgeries to repair damaged parts of the body c...

  9. MOCK SURGERIES IN AYURVEDA

    OpenAIRE

    Bali Yogitha

    2012-01-01

    The present trend is very well aware of mock tests, exams and even the mock surgeries that are very common in healthcare and play an important role in providing the surgeons, the necessary practical knowledge and expertise in their specialized field. In addition, patients also get benefited by the mock surgeries by having the complete knowledge before they undergo any surgery. The same concept of mock or the experimental surgeries can be found explained centuries ago by Susrutha, father of bo...

  10. Pediatric heart surgery

    Science.gov (United States)

    Heart surgery - pediatric; Heart surgery for children; Acquired heart disease; Heart valve surgery - children ... There are many kinds of heart defects. Some are minor, and others are more serious. Defects can occur inside the heart or in the large blood vessels ...

  11. Predicting Surgery Targets in Temporal Lobe Epilepsy through Structural Connectome Based Simulations.

    Directory of Open Access Journals (Sweden)

    Frances Hutchings

    2015-12-01

    Full Text Available Temporal lobe epilepsy (TLE is a prevalent neurological disorder resulting in disruptive seizures. In the case of drug resistant epilepsy resective surgery is often considered. This is a procedure hampered by unpredictable success rates, with many patients continuing to have seizures even after surgery. In this study we apply a computational model of epilepsy to patient specific structural connectivity derived from diffusion tensor imaging (DTI of 22 individuals with left TLE and 39 healthy controls. We validate the model by examining patient-control differences in simulated seizure onset time and network location. We then investigate the potential of the model for surgery prediction by performing in silico surgical resections, removing nodes from patient networks and comparing seizure likelihood post-surgery to pre-surgery simulations. We find that, first, patients tend to transit from non-epileptic to epileptic states more often than controls in the model. Second, regions in the left hemisphere (particularly within temporal and subcortical regions that are known to be involved in TLE are the most frequent starting points for seizures in patients in the model. In addition, our analysis also implicates regions in the contralateral and frontal locations which may play a role in seizure spreading or surgery resistance. Finally, the model predicts that patient-specific surgery (resection areas chosen on an individual, model-prompted, basis and not following a predefined procedure may lead to better outcomes than the currently used routine clinical procedure. Taken together this work provides a first step towards patient specific computational modelling of epilepsy surgery in order to inform treatment strategies in individuals.

  12. Limb salvage surgery.

    Science.gov (United States)

    Kadam, Dinesh

    2013-05-01

    The threat of lower limb loss is seen commonly in severe crush injury, cancer ablation, diabetes, peripheral vascular disease and neuropathy. The primary goal of limb salvage is to restore and maintain stability and ambulation. Reconstructive strategies differ in each condition such as: Meticulous debridement and early coverage in trauma, replacing lost functional units in cancer ablation, improving vascularity in ischaemic leg and providing stable walking surface for trophic ulcer. The decision to salvage the critically injured limb is multifactorial and should be individualised along with laid down definitive indications. Early cover remains the standard of care, delayed wound coverage not necessarily affect the final outcome. Limb salvage is more cost-effective than amputations in a long run. Limb salvage is the choice of procedure over amputation in 95% of limb sarcoma without affecting the survival. Compound flaps with different tissue components, skeletal reconstruction; tendon transfer/reconstruction helps to restore function. Adjuvant radiation alters tissue characters and calls for modification in reconstructive plan. Neuropathic ulcers are wide and deep often complicated by osteomyelitis. Free flap reconstruction aids in faster healing and provides superior surface for offloading. Diabetic wounds are primarily due to neuropathy and leads to six-fold increase in ulcerations. Control of infections, aggressive debridement and vascular cover are the mainstay of management. Endovascular procedures are gaining importance and have reduced extent of surgery and increased amputation free survival period. Though the standard approach remains utilising best option in the reconstruction ladder, the recent trend shows running down the ladder of reconstruction with newer reliable local flaps and negative wound pressure therapy.

  13. Limb salvage surgery

    Directory of Open Access Journals (Sweden)

    Dinesh Kadam

    2013-01-01

    Full Text Available The threat of lower limb loss is seen commonly in severe crush injury, cancer ablation, diabetes, peripheral vascular disease and neuropathy. The primary goal of limb salvage is to restore and maintain stability and ambulation. Reconstructive strategies differ in each condition such as: Meticulous debridement and early coverage in trauma, replacing lost functional units in cancer ablation, improving vascularity in ischaemic leg and providing stable walking surface for trophic ulcer. The decision to salvage the critically injured limb is multifactorial and should be individualised along with laid down definitive indications. Early cover remains the standard of care, delayed wound coverage not necessarily affect the final outcome. Limb salvage is more cost-effective than amputations in a long run. Limb salvage is the choice of procedure over amputation in 95% of limb sarcoma without affecting the survival. Compound flaps with different tissue components, skeletal reconstruction; tendon transfer/reconstruction helps to restore function. Adjuvant radiation alters tissue characters and calls for modification in reconstructive plan. Neuropathic ulcers are wide and deep often complicated by osteomyelitis. Free flap reconstruction aids in faster healing and provides superior surface for offloading. Diabetic wounds are primarily due to neuropathy and leads to six-fold increase in ulcerations. Control of infections, aggressive debridement and vascular cover are the mainstay of management. Endovascular procedures are gaining importance and have reduced extent of surgery and increased amputation free survival period. Though the standard approach remains utilising best option in the reconstruction ladder, the recent trend shows running down the ladder of reconstruction with newer reliable local flaps and negative wound pressure therapy.

  14. Implementation of an interactive liver surgery planning system

    Science.gov (United States)

    Wang, Luyao; Liu, Jingjing; Yuan, Rong; Gu, Shuguo; Yu, Long; Li, Zhitao; Li, Yanzhao; Li, Zhen; Xie, Qingguo; Hu, Daoyu

    2011-03-01

    Liver tumor, one of the most wide-spread diseases, has a very high mortality in China. To improve success rates of liver surgeries and life qualities of such patients, we implement an interactive liver surgery planning system based on contrastenhanced liver CT images. The system consists of five modules: pre-processing, segmentation, modeling, quantitative analysis and surgery simulation. The Graph Cuts method is utilized to automatically segment the liver based on an anatomical prior knowledge that liver is the biggest organ and has almost homogeneous gray value. The system supports users to build patient-specific liver segment and sub-segment models using interactive portal vein branch labeling, and to perform anatomical resection simulation. It also provides several tools to simulate atypical resection, including resection plane, sphere and curved surface. To match actual surgery resections well and simulate the process flexibly, we extend our work to develop a virtual scalpel model and simulate the scalpel movement in the hepatic tissue using multi-plane continuous resection. In addition, the quantitative analysis module makes it possible to assess the risk of a liver surgery. The preliminary results show that the system has the potential to offer an accurate 3D delineation of the liver anatomy, as well as the tumors' location in relation to vessels, and to facilitate liver resection surgeries. Furthermore, we are testing the system in a full-scale clinical trial.

  15. Motion magnification for endoscopic surgery

    Science.gov (United States)

    McLeod, A. Jonathan; Baxter, John S. H.; de Ribaupierre, Sandrine; Peters, Terry M.

    2014-03-01

    Endoscopic and laparoscopic surgeries are used for many minimally invasive procedures but limit the visual and haptic feedback available to the surgeon. This can make vessel sparing procedures particularly challenging to perform. Previous approaches have focused on hardware intensive intraoperative imaging or augmented reality systems that are difficult to integrate into the operating room. This paper presents a simple approach in which motion is visually enhanced in the endoscopic video to reveal pulsating arteries. This is accomplished by amplifying subtle, periodic changes in intensity coinciding with the patient's pulse. This method is then applied to two procedures to illustrate its potential. The first, endoscopic third ventriculostomy, is a neurosurgical procedure where the floor of the third ventricle must be fenestrated without injury to the basilar artery. The second, nerve-sparing robotic prostatectomy, involves removing the prostate while limiting damage to the neurovascular bundles. In both procedures, motion magnification can enhance subtle pulsation in these structures to aid in identifying and avoiding them.

  16. Pneumatic tourniquets in extremity surgery.

    LENUS (Irish Health Repository)

    Wakai, A

    2012-02-03

    Pneumatic tourniquets maintain a relatively bloodless field during extremity surgery, minimize blood loss, aid identification of vital structures, and expedite the procedure. However, they may induce an ischemia-reperfusion injury with potentially harmful local and systemic consequences. Modern pneumatic tourniquets are designed with mechanisms to regulate and maintain pressure. Routine maintenance helps ensure that these systems are working properly. The complications of tourniquet use include postoperative swelling, delay of recovery of muscle power, compression neurapraxia, wound hematoma with the potential for infection, vascular injury, tissue necrosis, and compartment syndrome. Systemic complications can also occur. The incidence of complications can be minimized by use of wider tourniquets, careful preoperative patient evaluation, and adherence to accepted principles of tourniquet use.

  17. Aid and Growth

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro and meso-levels, recent literature has turned decidedly pessimistic with respect to the ability of foreign aid to foster economic growth. Policy implications, such as the complete cessation of aid to Africa......, are being drawn on the basis of fragile evidence. This paper first assesses the aid-growth literature with a focus on recent contributions. The aid-growth literature is then framed, for the first time, in terms of the Rubin Causal Model, applied at the macroeconomic level. Our results show that aid has...... a positive and statistically significant causal effect on growth over the long run with point estimates at levels suggested by growth theory. We conclude that aid remains an important tool for enhancing the development prospects of poor nations....

  18. Aid Effectiveness on Growth

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL (aid effectiveness literature) is econo¬metric studies of the macroeconomic effects of development aid. It contains about 100 papers of which 68 are reduced form estimates of theeffect of aid on growth in the recipient country. The raw data show that growth is unconnected to aid......, but the AEL has put so much structure on the data that all results possible have emerged. The present meta study considers both the best-set of the 68 papers and the all-set of 543 regressions published. Both sets have a positive average aid-growth elasticity, but it is small and insignificant: The AEL has...... not established that aid works. Using meta-regression analysis it is shown that about 20 factors influence the results. Much of the variation between studies is an artifact and can be attributed to publication outlet, institu¬tional affiliation, and specification differences. However, some of the difference...

  19. Mathematical modeling of coupled drug and drug-encapsulated nanoparticle transport in patient-specific coronary artery walls

    KAUST Repository

    Hossain, Shaolie S.

    2011-08-20

    The majority of heart attacks occur when there is a sudden rupture of atherosclerotic plaque, exposing prothrombotic emboli to coronary blood flow, forming clots that can cause blockages of the arterial lumen. Diseased arteries can be treated with drugs delivered locally to vulnerable plaques. The objective of this work was to develop a computational tool-set to support the design and analysis of a catheter-based nanoparticulate drug delivery system to treat vulnerable plaques and diffuse atherosclerosis. A threedimensional mathematical model of coupled mass transport of drug and drug-encapsulated nanoparticles was developed and solved numerically utilizing isogeometric finite element analysis. Simulations were run on a patient-specific multilayered coronary artery wall segment with a vulnerable plaque and the effect of artery and plaque inhomogeneity was analyzed. The method captured trends observed in local drug delivery and demonstrated potential for optimizing drug design parameters, including delivery location, nanoparticle surface properties, and drug release rate. © Springer-Verlag 2011.

  20. Personalised computational cardiology: Patient-specific modelling in cardiac mechanics and biomaterial injection therapies for myocardial infarction

    Science.gov (United States)

    Sack, Kevin L.; Davies, Neil H.; Guccione, Julius M.

    2016-01-01

    Predictive computational modelling in biomedical research offers the potential to integrate diverse data, uncover biological mechanisms that are not easily accessible through experimental methods and expose gaps in knowledge requiring further research. Recent developments in computing and diagnostic technologies have initiated the advancement of computational models in terms of complexity and specificity. Consequently, computational modelling can increasingly be utilised as enabling and complementing modality in the clinic—with medical decisions and interventions being personalised. Myocardial infarction and heart failure are amongst the leading causes of death globally despite optimal modern treatment. The development of novel MI therapies is challenging and may be greatly facilitated through predictive modelling. Here, we review the advances in patient-specific modelling of cardiac mechanics, distinguishing specificity in cardiac geometry, myofibre architecture and mechanical tissue properties. Thereafter, the focus narrows to the mechanics of the infarcted heart and treatment of myocardial infarction with particular attention on intramyocardial biomaterial delivery. PMID:26833320

  1. Mathematical modeling of coupled drug and drug-encapsulated nanoparticle transport in patient-specific coronary artery walls

    Science.gov (United States)

    Hossain, Shaolie S.; Hossainy, Syed F. A.; Bazilevs, Yuri; Calo, Victor M.; Hughes, Thomas J. R.

    2012-02-01

    The majority of heart attacks occur when there is a sudden rupture of atherosclerotic plaque, exposing prothrombotic emboli to coronary blood flow, forming clots that can cause blockages of the arterial lumen. Diseased arteries can be treated with drugs delivered locally to vulnerable plaques. The objective of this work was to develop a computational tool-set to support the design and analysis of a catheter-based nanoparticulate drug delivery system to treat vulnerable plaques and diffuse atherosclerosis. A three-dimensional mathematical model of coupled mass transport of drug and drug-encapsulated nanoparticles was developed and solved numerically utilizing isogeometric finite element analysis. Simulations were run on a patient-specific multilayered coronary artery wall segment with a vulnerable plaque and the effect of artery and plaque inhomogeneity was analyzed. The method captured trends observed in local drug delivery and demonstrated potential for optimizing drug design parameters, including delivery location, nanoparticle surface properties, and drug release rate.

  2. Radiographic imaging of aids

    CERN Document Server

    Mahmoud, M B

    2002-01-01

    The acquired immunodeficiency syndrome (AIDS) has impacted the civilized world like no other disease. This research aimed to discuss some of the main aids-related complications and their detection by radiology tests, specifically central nervous system and musculoskeletal system disorders. The objectives are: to show specific characteristics of various diseases of HIV patient, to analyze the effect of pathology in patients by radiology, to enhance the knowledge of technologists in aids imaging and to improve communication skills between patient and radiology technologists.

  3. Hearing Aids and Music

    OpenAIRE

    Chasin, Marshall; Russo, Frank A.

    2004-01-01

    Historically, the primary concern for hearing aid design and fitting is optimization for speech inputs. However, increasingly other types of inputs are being investigated and this is certainly the case for music. Whether the hearing aid wearer is a musician or merely someone who likes to listen to music, the electronic and electro-acoustic parameters described can be optimized for music as well as for speech. That is, a hearing aid optimally set for music can be optimally set for speech, even...

  4. AIDS: acquired immunodeficiency syndrome

    OpenAIRE

    Gilmore, N. J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    2002-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Ca...

  5. Development and preliminary evaluation of a prototype audiovisual biofeedback device incorporating a patient-specific guiding waveform

    International Nuclear Information System (INIS)

    The aim of this research was to investigate the effectiveness of a novel audio-visual biofeedback respiratory training tool to reduce respiratory irregularity. The audiovisual biofeedback system acquires sample respiratory waveforms of a particular patient and computes a patient-specific waveform to guide the patient's subsequent breathing. Two visual feedback models with different displays and cognitive loads were investigated: a bar model and a wave model. The audio instructions were ascending/descending musical tones played at inhale and exhale respectively to assist in maintaining the breathing period. Free-breathing, bar model and wave model training was performed on ten volunteers for 5 min for three repeat sessions. A total of 90 respiratory waveforms were acquired. It was found that the bar model was superior to free breathing with overall rms displacement variations of 0.10 and 0.16 cm, respectively, and rms period variations of 0.77 and 0.33 s, respectively. The wave model was superior to the bar model and free breathing for all volunteers, with an overall rms displacement of 0.08 cm and rms periods of 0.2 s. The reduction in the displacement and period variations for the bar model compared with free breathing was statistically significant (p = 0.005 and 0.002, respectively); the wave model was significantly better than the bar model (p = 0.006 and 0.005, respectively). Audiovisual biofeedback with a patient-specific guiding waveform significantly reduces variations in breathing. The wave model approach reduces cycle-to-cycle variations in displacement by greater than 50% and variations in period by over 70% compared with free breathing. The planned application of this device is anatomic and functional imaging procedures and radiation therapy delivery. (note)

  6. A human pluripotent stem cell model of catecholaminergic polymorphic ventricular tachycardia recapitulates patient-specific drug responses

    Directory of Open Access Journals (Sweden)

    Marcela K. Preininger

    2016-09-01

    Full Text Available Although β-blockers can be used to eliminate stress-induced ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT, this treatment is unsuccessful in ∼25% of cases. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs generated from these patients have potential for use in investigating the phenomenon, but it remains unknown whether they can recapitulate patient-specific drug responses to β-blockers. This study assessed whether the inadequacy of β-blocker therapy in an individual can be observed in vitro using patient-derived CPVT iPSC-CMs. An individual with CPVT harboring a novel mutation in the type 2 cardiac ryanodine receptor (RyR2 was identified whose persistent ventricular arrhythmias during β-blockade with nadolol were abolished during flecainide treatment. iPSC-CMs generated from this patient and two control individuals expressed comparable levels of excitation-contraction genes, but assessment of the sarcoplasmic reticulum Ca2+ leak and load relationship revealed intracellular Ca2+ homeostasis was altered in the CPVT iPSC-CMs. β-adrenergic stimulation potentiated spontaneous Ca2+ waves and unduly frequent, large and prolonged Ca2+ sparks in CPVT compared with control iPSC-CMs, validating the disease phenotype. Pursuant to the patient's in vivo responses, nadolol treatment during β-adrenergic stimulation achieved negligible reduction of Ca2+ wave frequency and failed to rescue Ca2+ spark defects in CPVT iPSC-CMs. In contrast, flecainide reduced both frequency and amplitude of Ca2+ waves and restored the frequency, width and duration of Ca2+ sparks to baseline levels. By recapitulating the improved response of an individual with CPVT to flecainide compared with β-blocker therapy in vitro, these data provide new evidence that iPSC-CMs can capture basic components of patient-specific drug responses.

  7. Development and preliminary evaluation of a prototype audiovisual biofeedback device incorporating a patient-specific guiding waveform

    Energy Technology Data Exchange (ETDEWEB)

    Venkat, Raghu B; Sawant, Amit; Suh, Yelin; Keall, Paul J [Department of Radiation Oncology, Stanford University, Stanford, CA 94305-5847 (United States); George, Rohini [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States)], E-mail: Paul.Keall@stanford.edu

    2008-06-07

    The aim of this research was to investigate the effectiveness of a novel audio-visual biofeedback respiratory training tool to reduce respiratory irregularity. The audiovisual biofeedback system acquires sample respiratory waveforms of a particular patient and computes a patient-specific waveform to guide the patient's subsequent breathing. Two visual feedback models with different displays and cognitive loads were investigated: a bar model and a wave model. The audio instructions were ascending/descending musical tones played at inhale and exhale respectively to assist in maintaining the breathing period. Free-breathing, bar model and wave model training was performed on ten volunteers for 5 min for three repeat sessions. A total of 90 respiratory waveforms were acquired. It was found that the bar model was superior to free breathing with overall rms displacement variations of 0.10 and 0.16 cm, respectively, and rms period variations of 0.77 and 0.33 s, respectively. The wave model was superior to the bar model and free breathing for all volunteers, with an overall rms displacement of 0.08 cm and rms periods of 0.2 s. The reduction in the displacement and period variations for the bar model compared with free breathing was statistically significant (p = 0.005 and 0.002, respectively); the wave model was significantly better than the bar model (p = 0.006 and 0.005, respectively). Audiovisual biofeedback with a patient-specific guiding waveform significantly reduces variations in breathing. The wave model approach reduces cycle-to-cycle variations in displacement by greater than 50% and variations in period by over 70% compared with free breathing. The planned application of this device is anatomic and functional imaging procedures and radiation therapy delivery. (note)

  8. NOTE: Development and preliminary evaluation of a prototype audiovisual biofeedback device incorporating a patient-specific guiding waveform

    Science.gov (United States)

    Venkat, Raghu B.; Sawant, Amit; Suh, Yelin; George, Rohini; Keall, Paul J.

    2008-06-01

    The aim of this research was to investigate the effectiveness of a novel audio-visual biofeedback respiratory training tool to reduce respiratory irregularity. The audiovisual biofeedback system acquires sample respiratory waveforms of a particular patient and computes a patient-specific waveform to guide the patient's subsequent breathing. Two visual feedback models with different displays and cognitive loads were investigated: a bar model and a wave model. The audio instructions were ascending/descending musical tones played at inhale and exhale respectively to assist in maintaining the breathing period. Free-breathing, bar model and wave model training was performed on ten volunteers for 5 min for three repeat sessions. A total of 90 respiratory waveforms were acquired. It was found that the bar model was superior to free breathing with overall rms displacement variations of 0.10 and 0.16 cm, respectively, and rms period variations of 0.77 and 0.33 s, respectively. The wave model was superior to the bar model and free breathing for all volunteers, with an overall rms displacement of 0.08 cm and rms periods of 0.2 s. The reduction in the displacement and period variations for the bar model compared with free breathing was statistically significant (p = 0.005 and 0.002, respectively); the wave model was significantly better than the bar model (p = 0.006 and 0.005, respectively). Audiovisual biofeedback with a patient-specific guiding waveform significantly reduces variations in breathing. The wave model approach reduces cycle-to-cycle variations in displacement by greater than 50% and variations in period by over 70% compared with free breathing. The planned application of this device is anatomic and functional imaging procedures and radiation therapy delivery.

  9. A human pluripotent stem cell model of catecholaminergic polymorphic ventricular tachycardia recapitulates patient-specific drug responses

    Science.gov (United States)

    Preininger, Marcela K.; Jha, Rajneesh; Maxwell, Joshua T.; Wu, Qingling; Singh, Monalisa; Dalal, Aarti; Mceachin, Zachary T.; Rossoll, Wilfried; Hales, Chadwick M.; Fischbach, Peter S.; Wagner, Mary B.

    2016-01-01

    ABSTRACT Although β-blockers can be used to eliminate stress-induced ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), this treatment is unsuccessful in ∼25% of cases. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from these patients have potential for use in investigating the phenomenon, but it remains unknown whether they can recapitulate patient-specific drug responses to β-blockers. This study assessed whether the inadequacy of β-blocker therapy in an individual can be observed in vitro using patient-derived CPVT iPSC-CMs. An individual with CPVT harboring a novel mutation in the type 2 cardiac ryanodine receptor (RyR2) was identified whose persistent ventricular arrhythmias during β-blockade with nadolol were abolished during flecainide treatment. iPSC-CMs generated from this patient and two control individuals expressed comparable levels of excitation-contraction genes, but assessment of the sarcoplasmic reticulum Ca2+ leak and load relationship revealed intracellular Ca2+ homeostasis was altered in the CPVT iPSC-CMs. β-adrenergic stimulation potentiated spontaneous Ca2+ waves and unduly frequent, large and prolonged Ca2+ sparks in CPVT compared with control iPSC-CMs, validating the disease phenotype. Pursuant to the patient's in vivo responses, nadolol treatment during β-adrenergic stimulation achieved negligible reduction of Ca2+ wave frequency and failed to rescue Ca2+ spark defects in CPVT iPSC-CMs. In contrast, flecainide reduced both frequency and amplitude of Ca2+ waves and restored the frequency, width and duration of Ca2+ sparks to baseline levels. By recapitulating the improved response of an individual with CPVT to flecainide compared with β-blocker therapy in vitro, these data provide new evidence that iPSC-CMs can capture basic components of patient-specific drug responses. PMID:27491078

  10. SU-E-T-475: An Accurate Linear Model of Tomotherapy MLC-Detector System for Patient Specific Delivery QA

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y; Mo, X; Chen, M; Olivera, G; Parnell, D; Key, S; Lu, W [21st Century Oncology, Madison, WI (United States); Reeher, M [21st Century Oncology, Naples, FL (United States); Galmarini, D [21st Century Oncology, Fort Myers, FL (United States)

    2014-06-01

    Purpose: An accurate leaf fluence model can be used in applications such as patient specific delivery QA and in-vivo dosimetry for TomoTherapy systems. It is known that the total fluence is not a linear combination of individual leaf fluence due to leakage-transmission, tongue-and-groove, and source occlusion effect. Here we propose a method to model the nonlinear effects as linear terms thus making the MLC-detector system a linear system. Methods: A leaf pattern basis (LPB) consisting of no-leaf-open, single-leaf-open, double-leaf-open and triple-leaf-open patterns are chosen to represent linear and major nonlinear effects of leaf fluence as a linear system. An arbitrary leaf pattern can be expressed as (or decomposed to) a linear combination of the LPB either pulse by pulse or weighted by dwelling time. The exit detector responses to the LPB are obtained by processing returned detector signals resulting from the predefined leaf patterns for each jaw setting. Through forward transformation, detector signal can be predicted given a delivery plan. An equivalent leaf open time (LOT) sinogram containing output variation information can also be inversely calculated from the measured detector signals. Twelve patient plans were delivered in air. The equivalent LOT sinograms were compared with their planned sinograms. Results: The whole calibration process was done in 20 minutes. For two randomly generated leaf patterns, 98.5% of the active channels showed differences within 0.5% of the local maximum between the predicted and measured signals. Averaged over the twelve plans, 90% of LOT errors were within +/−10 ms. The LOT systematic error increases and shows an oscillating pattern when LOT is shorter than 50 ms. Conclusion: The LPB method models the MLC-detector response accurately, which improves patient specific delivery QA and in-vivo dosimetry for TomoTherapy systems. It is sensitive enough to detect systematic LOT errors as small as 10 ms.

  11. Patient-specific scatter correction for flat-panel detector-based cone-beam CT imaging

    Science.gov (United States)

    Zhao, Wei; Brunner, Stephen; Niu, Kai; Schafer, Sebastian; Royalty, Kevin; Chen, Guang-Hong

    2015-02-01

    A patient-specific scatter correction algorithm is proposed to mitigate scatter artefacts in cone-beam CT (CBCT). The approach belongs to the category of convolution-based methods in which a scatter potential function is convolved with a convolution kernel to estimate the scatter profile. A key step in this method is to determine the free parameters introduced in both scatter potential and convolution kernel using a so-called calibration process, which is to seek for the optimal parameters such that the models for both scatter potential and convolution kernel is able to optimally fit the previously known coarse estimates of scatter profiles of the image object. Both direct measurements and Monte Carlo (MC) simulations have been proposed by other investigators to achieve the aforementioned rough estimates. In the present paper, a novel method has been proposed and validated to generate the needed coarse scatter profile for parameter calibration in the convolution method. The method is based upon an image segmentation of the scatter contaminated CBCT image volume, followed by a reprojection of the segmented image volume using a given x-ray spectrum. The reprojected data is subtracted from the scatter contaminated projection data to generate a coarse estimate of the needed scatter profile used in parameter calibration. The method was qualitatively and quantitatively evaluated using numerical simulations and experimental CBCT data acquired on a clinical CBCT imaging system. Results show that the proposed algorithm can significantly reduce scatter artefacts and recover the correct CT number. Numerical simulation results show the method is patient specific, can accurately estimate the scatter, and is robust with respect to segmentation procedure. For experimental and in vivo human data, the results show the CT number can be successfully recovered and anatomical structure visibility can be significantly improved.

  12. SU-E-T-345: Validation of a Patient-Specific Monte Carlo Targeted Radionuclide Therapy Dosimetry Platform

    Energy Technology Data Exchange (ETDEWEB)

    Besemer, A; Bednarz, B [University of Wisconsin, Madison, WI (United States)

    2014-06-01

    Purpose: There is a compelling need for personalized dosimetry in targeted radionuclide therapy given that conventional dose calculation methods fail to accurately predict dose response relationships. To address this need, we have developed a Geant4-based Monte Carlo patient-specific 3D dosimetry platform for TRT. This platform calculates patient-specific dose distributions based on serial CT/PET or CT/SPECT images acquired after injection of the TRT agent. In this work, S-values and specific absorbed fractions (SAFs) were calculated using this platform and benchmarked against reference values. Methods: S-values for 1, 10, 100, and 1000g spherical tumors with uniform activity distributions of I-124, I-125, I-131, F-18, and Ra-223 were calculated and compared to OLINDA/EXM reference values. SAFs for monoenergetic photons of 0.01, 0.1, and 1 MeV and S factors for monoenergetic electrons of 0.935 MeV were calculated for the liver, kidneys, lungs, pancreas, spleen, and adrenals in the Zubal Phantom and compared with previously published values. Sufficient particles were simulated to keep the voxel statistical uncertainty below 5%. Results: The calculated spherical S-values agreed within a few percent of reference data from OLINDA/EXM for each radionuclide and sphere size. The comparison of photon SAFs and electron S-values with previously published values showed good agreement with the previously published values. The S-values and SAFs of the source organs agreed within 1%. Conclusion: Our platform has been benchmarked against reference values for a variety of radionuclides and over a wide range of energies and tumor sizes. Therefore, this platform could be used to provide accurate patientspecific dosimetry for use in radiopharmaceutical clinical trials.

  13. Aid, growth, and development

    DEFF Research Database (Denmark)

    Arndt, Channing; Jones, Edward Samuel; Tarp, Finn

    2010-01-01

    The micro-macro paradox has been revived. Despite broadly positive evaluations at the micro- and meso-levels, recent literature doubts the ability of foreign aid to foster economic growth and development. This paper assesses the aid-growth literature and, taking inspiration from the program...... evaluation literature, we re-examine key hypotheses. In our findings, aid has a positive and statistically significant causal effect on growth over the long run, with confidence intervals conforming to levels suggested by growth theory. Aid remains a key tool for enhancing the development prospects of poor...

  14. Music and hearing aids.

    Science.gov (United States)

    Madsen, Sara M K; Moore, Brian C J

    2014-01-01

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems. PMID:25361601

  15. Music and Hearing Aids

    Directory of Open Access Journals (Sweden)

    Sara M. K. Madsen

    2014-10-01

    Full Text Available The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems.

  16. HIV / AIDS Network.

    Science.gov (United States)

    1995-01-01

    The HIV/AIDS Network and the Philippines Department of Health (DOH) collaborated to produce the AIDS Candlelight Memorial at the Philippine International Convention Center (PICC), May 1995, and World AIDS Day activities on December 1, 1995. After the memorial, a fashion show, "Body Shots," provided a channel for information on acquired immunodeficiency syndrome (AIDS). On World AIDS Day, at the request of DOH, the Network provided speakers who lectured on human immunodeficiency virus (HIV) and AIDS in different government offices. Prior to World AIDS Day, the Network focused on strengthening its cohesiveness and building the capabilities of its member organizations through lectures and symposia during November. Network activities were coordinated by the Remedios AIDS Foundation with support from the other members of the Coordinating Council: Health Action Information Network (HAIN); Caritas; Kabalikat, Stop Trafficking of Pilopinos Foundation, Inc. (STOP);and the Library Foundation (TLF). The Coordinating Council elected for 1996 includes the Remedios AIDS Foundation, HAIN, Caritas, TLF, STOP, the Foundation for Adolescent Development (FAD), and the Salvation Army. PMID:12291699

  17. Music and hearing aids.

    Science.gov (United States)

    Madsen, Sara M K; Moore, Brian C J

    2014-10-31

    The signal processing and fitting methods used for hearing aids have mainly been designed to optimize the intelligibility of speech. Little attention has been paid to the effectiveness of hearing aids for listening to music. Perhaps as a consequence, many hearing-aid users complain that they are not satisfied with their hearing aids when listening to music. This issue inspired the Internet-based survey presented here. The survey was designed to identify the nature and prevalence of problems associated with listening to live and reproduced music with hearing aids. Responses from 523 hearing-aid users to 21 multiple-choice questions are presented and analyzed, and the relationships between responses to questions regarding music and questions concerned with information about the respondents, their hearing aids, and their hearing loss are described. Large proportions of the respondents reported that they found their hearing aids to be helpful for listening to both live and reproduced music, although less so for the former. The survey also identified problems such as distortion, acoustic feedback, insufficient or excessive gain, unbalanced frequency response, and reduced tone quality. The results indicate that the enjoyment of listening to music with hearing aids could be improved by an increase of the input and output dynamic range, extension of the low-frequency response, and improvement of feedback cancellation and automatic gain control systems.

  18. Stapes surgery: a National Survey of British Otologists.

    Science.gov (United States)

    Lancer, Hannah; Manickavasagam, Jaiganesh; Zaman, Azreena; Lancer, Jack

    2016-02-01

    To investigate individual stapes surgery practice in the UK, a retrospective study was conducted by postal questionnaire to all 'assumed' stapes-performing otologists. 225 questionnaires were sent out to practicing otologists in the UK. 184 replies (81.8 %) indicated that 134 (72.9 %) otologists perform stapes surgery [stapedectomy (8.2 %), stapedotomy (91.0 %) or other (0.8 %)]. The '6-10 stapes operation per year' category is the most common, with most using general anaesthetic (GA) (78.3 %). Unilateral surgery is advised in 89.6 %, and 96.3 % perform second-side surgery, with all advising the option of a hearing aid prior to surgery. The majority (88.1 %) would fit the prosthesis after removing the stapes, with the top three prostheses being Causse, Smart and Teflon (as described by respondents). 42.5 % always use a vein graft or fat to cover the fenestration, 9.3 % use a laser and 48.5 % carry out the surgery as a day case. For an overhanging facial nerve (less than 50 % of the footplate obscured), the majority stated that it would depend whether they would abandon surgery. 25.4 % have encountered a 'gusher' and 83.6 % would recommend revision surgery. 82.8 % have a registrar present when carrying out stapes operations, but 69.4 % only offer training to trainees with an otological interest. In the UK, stapedotomy is the preferred technique. Most prefer the Causse prosthesis, general anaesthesia and an inpatient stay. Hearing aids are advised prior to surgery. Day-case and inpatient practice is about equal. 'Gushers' are encountered rarely. Revision surgery is advised if a conductive loss returns. Flying is recommended from 6 weeks. Most otologists are willing to teach trainees with an otological interest.

  19. AIDS is your business.

    Science.gov (United States)

    Rosen, Sydney; Simon, Jonathon; Vincent, Jeffrey R; MacLeod, William; Fox, Matthew; Thea, Donald M

    2003-02-01

    If your company operates in a developing country, AIDS is your business. While Africa has received the most attention, AIDS is also spreading swiftly in other parts of the world. Russia and Ukraine had the fastest-growing epidemics last year, and many experts believe China and India will suffer the next tidal wave of infection. Why should executives be concerned about AIDS? Because it is destroying the twin rationales of globalization strategy-cheap labor and fast-growing markets--in countries where people are heavily affected by the epidemic. Fortunately, investments in programs that prevent infection and provide treatment for employees who have HIV/AIDS are profitable for many businesses--that is, they lead to savings that outweigh the programs' costs. Due to the long latency period between HIV infection and the onset of AIDS symptoms, a company is not likely to see any of the costs of HIV/AIDS until five to ten years after an employee is infected. But executives can calculate the present value of epidemic-related costs by using the discount rate to weigh each cost according to its expected timing. That allows companies to think about expenses on HIV/AIDS prevention and treatment programs as investments rather than merely as costs. The authors found that the annual cost of AIDS to six corporations in South Africa and Botswana ranged from 0.4% to 5.9% of the wage bill. All six companies would have earned positive returns on their investments if they had provided employees with free treatment for HIV/AIDS in the form of highly active antiretroviral therapy (HAART), according to the mathematical model the authors used. The annual reduction in the AIDS "tax" would have been as much as 40.4%. The authors' conclusion? Fighting AIDS not only helps those infected; it also makes good business sense. PMID:12577655

  20. Surgery for Benign Salivary Neoplasms.

    Science.gov (United States)

    Gillespie, M Boyd; Iro, Heinrich

    2016-01-01

    Salivary neoplasms are relatively infrequent entities that account for only 4% of tumors of the head and neck. Although slow-growing lesions of the preauricular area and submandibular space are often confused with sebaceous cysts, lymph nodes, or lipomas by the non-otolaryngologist, otolaryngologists-head and neck surgeons recognize that all preauricular and submandibular masses should be considered a salivary neoplasm until proven otherwise. Surgery remains the treatment of choice for benign salivary gland neoplasms; however, techniques continue to evolve in order to preserve salivary function and reduce surgical morbidity. The goals of management of benign salivary neoplasms include accurate diagnosis of the lesion, complete surgical extirpation, and functional preservation of adjacent cranial nerves. Accurate diagnosis is aided by appropriate preoperative physical examination, imaging, and fine needle aspiration biopsy. Benign neoplasms typically present as slow-growing, painless, mobile masses without adverse features, such as tissue fixation, ulceration, a cranial nerve deficit, or regional lymphadenopathy. Preoperative imaging with ultrasonography, computed tomography, or magnetic resonance imaging reveals well-circumscribed lesions without an infiltrative growth pattern or associated adenopathy. Fine needle aspiration biopsy may favor a benign neoplasm, supporting the clinical presentation. Surgery for a benign or malignant salivary neoplasm is in essence a false dichotomy since the surgeon can never be completely confident of the diagnosis until the specimen is removed. The surgeon must recognize the significant overlap between benign and malignant salivary masses in terms of clinical presentation, imaging, and cytology, which requires the surgeon to remain vigilant and flexible at the time of surgery should tissue characteristics or frozen section analysis suggest a malignant process.

  1. Laparoscopic cholecystectomy causes less sleep disturbance than open abdominal surgery

    DEFF Research Database (Denmark)

    Gögenur, I; Rosenberg-Adamsen, S; Kiil, C;

    2001-01-01

    BACKGROUND: The aim of this study was to examine subjective sleep quality before and after laparoscopic vs open abdominal surgery. METHODS: Twelve patients undergoing laparoscopic cholecystectomy and 15 patients undergoing laparotomy were evaluated with the aid of a sleep questionnaire from 4 day...

  2. Clinical Pearls in Anaesthesia for Endoscopic Endonasal Transsphenoid Pituitary Macroadenoma Surgery

    Directory of Open Access Journals (Sweden)

    Shah Shagun B

    2015-11-01

    Full Text Available Endoscopic Endonasal Trans-sphenoid Surgery (EETS aided by avant-garde neuro-navigation techniques, ultrasonic aspirators and bone curettes has come of age. Endoscopic surgery supersedes conventional microscopic approach due to better visualization, avoidance of craniotomy, brain retraction and undue neurovascular manipulation with less morbidity, blood loss and improved safety. Anaesthetic techniques must be tailored to cater for such advances in surgery.

  3. AIDS Epidemiological models

    Science.gov (United States)

    Rahmani, Fouad Lazhar

    2010-11-01

    The aim of this paper is to present mathematical modelling of the spread of infection in the context of the transmission of the human immunodeficiency virus (HIV) and the acquired immune deficiency syndrome (AIDS). These models are based in part on the models suggested in the field of th AIDS mathematical modelling as reported by ISHAM [6].

  4. AIDS as Metaphor.

    Science.gov (United States)

    McMillen, Liz

    1994-01-01

    Scholarly interest in Acquired Immune Deficiency Syndrome (AIDS) has spread throughout the humanities, attracting the attention of historians of medicine, political scientists, sociologists, public health scholars, and anthropologists. Most theorists hope their research will aid in policymaking or change understanding of the epidemic. (MSE)

  5. [Oral hygiene aids].

    Science.gov (United States)

    Hovius, M; Leemans, G J

    1994-05-01

    Different dental hygiene aids are discussed, such as floss, tape, superfloss, gauze, flat shoelace, toothpick, interproximal brush, single-tufted brush, electric toothbrush, manual toothbrush and oral irrigation. Research shows that not one specific aid is superior to another if effectiveness is taken into consideration. Other factors which can influence oral hygiene efficacy are discussed as well. PMID:11830968

  6. AIDS and Chemical Dependency.

    Science.gov (United States)

    Pohl, Melvin I.

    After defining HIV and the AIDS disease and outlining symptoms and means of infection, this fact sheet lists the ways alcohol and drugs are involved with the AIDS epidemic, noting that needle-sharing transmits the virus; that alcohol or mood-altering drugs like crack cocaine cause disinhibition, increase sex drive, encourage sex for drugs, and…

  7. Changing epidemiology of AIDS.

    OpenAIRE

    Donovan, C. A.; Stratton, E.

    1994-01-01

    It has been 15 years since AIDS made its first appearance in North America, probably longer worldwide. In that time, our knowledge of the epidemiology of AIDS has grown and changed. This review highlights significant aspects of the epidemic with particular emphasis on the evolution of this disease in North America.

  8. The Aid Effectiveness Literature

    DEFF Research Database (Denmark)

    Doucouliagos, Hristos; Paldam, Martin

    The AEL consists of empirical macro studies of the effects of development aid. At the end of 2004 it had reached 97 studies of three families, which we have summarized in one study each using meta-analysis. Studies of the effect on investments show that they rise by 1/3 of the aid – the rest is c...

  9. Aid and Income

    DEFF Research Database (Denmark)

    Lof, Matthijs; Mekasha, Tseday Jemaneh; Tarp, Finn

    2015-01-01

    to nonrandom omission of a large proportion of observations. Furthermore, we show that NDHKM’s use of co-integrated regressions is not a suitable empirical strategy for estimating the causal effect of aid on income. Evidence from a Panel VAR model estimated on the dataset of NDHKM, suggests a positive...... and statistically significant long-run effect of aid on income....

  10. International Aid to Education

    Science.gov (United States)

    Benavot, Aaron

    2010-01-01

    Recent evidence highlights several worrisome trends regarding aid pledges and disbursements, which have been exacerbated by the global financial crisis. First, while overall development assistance rose in 2008, after 2 years of decline, the share of all sector aid going to the education sector has remained virtually unchanged at about 12 percent…

  11. Genetic Immunity to AIDS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In an article on genetic immunity to AIDS published in Science magazine, American and Chinese scientists claim to have discovered why certain HIV carriers do not develop full-blown AIDS. They say that the key to this conundrum lies in a particular protein in the endocrine system that inhibits development of HIV.

  12. Hearing aid and Noise

    OpenAIRE

    Ahmad Reza Nazeri

    1999-01-01

    Prescription of hearing aid is an extensive special category of knowledge in the field of audiology. This article is aimed at discussing the function of hearing aid and also management of patients in the noisy environments and presenting solutions to overcome problems regarding to this issue along with taking a look to the equipments prepared nowadays to cope with noisy situations.

  13. Implementing AIDS Education

    Directory of Open Access Journals (Sweden)

    Grace C. Huerta

    1996-08-01

    Full Text Available The world has been challenged by the AIDS epidemic for 15 years. In 1985, the U.S. Department of Health and Human Services, Centers for Disease Control, allocated funds to all state departments of education to assist schools in the development of AIDS education policies and programs. Yet, these policies do not ensure that all students receive effective AIDS education. On September 21, 1991, the Arizona Legislature passed Senate Bill 1396, which requires public schools to annually provide AIDS education in grades K-12. The bill was rescinded in 1995. With prohibitive curriculum guidelines, limited teacher training opportunities and tremendous instructional demands, this educational policy was implemented in disparate forms. By examining the perspectives of the Arizona educators (representing three school districts, this qualitative study reveals how teachers ultimately controlled the delivery and nature of AIDS instruction based upon personal values, views of teacher roles, and their interpretation of the mandate itself.

  14. [Single Port Thoracic Surgery and Reduced Port Thoracic Surgery].

    Science.gov (United States)

    Onodera, Ken; Noda, Masafumi

    2016-07-01

    Single port thoracic surgery, reduced port surgery and needlescopic surgery attract attention as one of the minimally invasive surgery in thoracic surgery recently. Single port thoracic surgery was advocated by Rocco in 2004, it was reported usefulness of single port thoracic surgery for primary spontaneous pneumothorax. The surgical procedure as single (or reduced) port thoracic surgery is roughly divided into the following. One is operated with instruments inserted from the single extended incision, and the other is operated with instruments punctured without extending incision. It is not generally complicated procedures in single port thoracic surgery. Primary spontaneous pneumothorax and biopsy for lung and pleura are considered the surgical indication for single (or reduced) port surgery. It is revealed that single port surgery for primary spontaneous pneumothorax is less invasive than conventional surgery. Single port and reduced port thoracic surgery will spread furthermore in the future. PMID:27440029

  15. Energy systems in surgery

    OpenAIRE

    Pantelić Miloš; Ljikar Jelena; Devečerski Gordana; Karadžić Jelena

    2015-01-01

    Introduction. The systems of energy in surgery are applied in order to achieve better and more effective performing of procedures. Whereas various energy sources, including electricity, ultrasound, laser and argon gas, may be used, the fundamental principle involves tissue necrosis and hemostasis by heating. Electro Surgery. Electro Surgery is a surgical technique by which surgical procedures are performed by focused heating of the tissue using devices base...

  16. Automatic bladder segmentation on CBCT for multiple plan ART of bladder cancer using a patient-specific bladder model

    Science.gov (United States)

    Chai, Xiangfei; van Herk, Marcel; Betgen, Anja; Hulshof, Maarten; Bel, Arjan

    2012-06-01

    In multiple plan adaptive radiotherapy (ART) strategies of bladder cancer, a library of plans corresponding to different bladder volumes is created based on images acquired in early treatment sessions. Subsequently, the plan for the smallest PTV safely covering the bladder on cone-beam CT (CBCT) is selected as the plan of the day. The aim of this study is to develop an automatic bladder segmentation approach suitable for CBCT scans and test its ability to select the appropriate plan from the library of plans for such an ART procedure. Twenty-three bladder cancer patients with a planning CT and on average 11.6 CBCT scans were included in our study. For each patient, all CBCT scans were matched to the planning CT on bony anatomy. Bladder contours were manually delineated for each planning CT (for model building) and CBCT (for model building and validation). The automatic segmentation method consisted of two steps. A patient-specific bladder deformation model was built from the training data set of each patient (the planning CT and the first five CBCT scans). Then, the model was applied to automatically segment bladders in the validation data of the same patient (the remaining CBCT scans). Principal component analysis (PCA) was applied to the training data to model patient-specific bladder deformation patterns. The number of PCA modes for each patient was chosen such that the bladder shapes in the training set could be represented by such number of PCA modes with less than 0.1 cm mean residual error. The automatic segmentation started from the bladder shape of a reference CBCT, which was adjusted by changing the weight of each PCA mode. As a result, the segmentation contour was deformed consistently with the training set to fit the bladder in the validation image. A cost function was defined by the absolute difference between the directional gradient field of reference CBCT sampled on the corresponding bladder contour and the directional gradient field of validation

  17. Complications of strabismus surgery

    Directory of Open Access Journals (Sweden)

    Scott E Olitsky

    2015-01-01

    Full Text Available All surgeries carry risks of complications, and there is no way to avoid ever having a complication. Strabismus surgery is no different in this regard. There are methods to reduce the risk of a complication during or after surgery, and these steps should always be taken. When a complication occurs, it is important to first recognize it and then manage it appropriately to allow for the best outcome possible. This article will discuss some of the more common and/or most devastating complications that can occur during or after strabismus surgery as well as thoughts on how to avoid them and manage them should they happen.

  18. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B;

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  19. Surgery center joint ventures.

    Science.gov (United States)

    Zasa, R J

    1999-01-01

    Surgery centers have been accepted as a cost effective, patient friendly vehicle for delivery of quality ambulatory care. Hospitals and physician groups also have made them the vehicles for coming together. Surgery centers allow hospitals and physicians to align incentives and share benefits. It is one of the few types of health care businesses physicians can own without anti-fraud and abuse violation. As a result, many surgery center ventures are now jointly owned by hospitals and physician groups. This article outlines common structures that have been used successfully to allow both to own and govern surgery centers.

  20. Hyperoxaluria and Bariatric Surgery

    Science.gov (United States)

    Asplin, John R.

    2007-04-01

    Bariatric surgery as a means to treat obesity is becoming increasingly common in the United States. An early form of bariatric surgery, the jejunoileal bypass, had to be abandoned in 1980 due to numerous complications, including hyperoxaluria and kidney stones. Current bariatric procedures have not been systematically evaluated to determine if they cause hyperoxaluria. Presented here are data showing that hyperoxaluria is the major metabolic abnormality in patients with bariatric surgery who form kidney stones. Further studies are needed to assess the prevalence of hyperoxaluria in all patients with bariatric surgery.

  1. Lung surgery - discharge

    Science.gov (United States)

    Thoracotomy - discharge; Lung tissue removal - discharge; Pneumonectomy - discharge; Lobectomy - discharge; Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - ...

  2. Generic method for automatic bladder segmentation on cone beam CT using a patient-specific bladder shape model

    Energy Technology Data Exchange (ETDEWEB)

    Schoot, A. J. A. J. van de, E-mail: a.j.schootvande@amc.uva.nl; Schooneveldt, G.; Wognum, S.; Stalpers, L. J. A.; Rasch, C. R. N.; Bel, A. [Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Hoogeman, M. S. [Department of Radiation Oncology, Daniel den Hoed Cancer Center, Erasmus Medical Center, Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands); Chai, X. [Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Palo Alto, California 94305 (United States)

    2014-03-15

    Purpose: The aim of this study is to develop and validate a generic method for automatic bladder segmentation on cone beam computed tomography (CBCT), independent of gender and treatment position (prone or supine), using only pretreatment imaging data. Methods: Data of 20 patients, treated for tumors in the pelvic region with the entire bladder visible on CT and CBCT, were divided into four equally sized groups based on gender and treatment position. The full and empty bladder contour, that can be acquired with pretreatment CT imaging, were used to generate a patient-specific bladder shape model. This model was used to guide the segmentation process on CBCT. To obtain the bladder segmentation, the reference bladder contour was deformed iteratively by maximizing the cross-correlation between directional grey value gradients over the reference and CBCT bladder edge. To overcome incorrect segmentations caused by CBCT image artifacts, automatic adaptations were implemented. Moreover, locally incorrect segmentations could be adapted manually. After each adapted segmentation, the bladder shape model was expanded and new shape patterns were calculated for following segmentations. All available CBCTs were used to validate the segmentation algorithm. The bladder segmentations were validated by comparison with the manual delineations and the segmentation performance was quantified using the Dice similarity coefficient (DSC), surface distance error (SDE) and SD of contour-to-contour distances. Also, bladder volumes obtained by manual delineations and segmentations were compared using a Bland-Altman error analysis. Results: The mean DSC, mean SDE, and mean SD of contour-to-contour distances between segmentations and manual delineations were 0.87, 0.27 cm and 0.22 cm (female, prone), 0.85, 0.28 cm and 0.22 cm (female, supine), 0.89, 0.21 cm and 0.17 cm (male, supine) and 0.88, 0.23 cm and 0.17 cm (male, prone), respectively. Manual local adaptations improved the segmentation

  3. Research Report: HIV/AIDS

    Science.gov (United States)

    ... Reports » HIV/AIDS » Letter from the Director HIV/AIDS Email Facebook Twitter Letter from the Director Human ... the virus that causes acquired immune deficiency syndrome (AIDS) — has been with us for three decades now. ...

  4. HIV/AIDS and Alcohol

    Science.gov (United States)

    ... Psychiatric Disorders Other Substance Abuse HIV/AIDS HIV/AIDS Human immunodeficiency virus (HIV) targets the body’s immune ... and often leads to acquired immune deficiency syndrome (AIDS). Each year in the United States, between 55, ...

  5. HIV, AIDS, and the Future

    Science.gov (United States)

    Skip Navigation Bar Home Current Issue Past Issues HIV / AIDS HIV, AIDS, and the Future Past Issues / Summer 2009 ... turn Javascript on. Photo: The NAMES Project Foundation HIV and AIDS are a global catastrophe. While advances ...

  6. HIV/AIDS: Women's Health

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  7. What Is HIV/AIDS?

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  8. HIV/AIDS and Vaccines

    Science.gov (United States)

    ... Hospitalization and Palliative Care Friends & Family Dating and Marriage Family Planning Mixed-Status Couples Discrimination Legal Issues ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS ...

  9. Pretreatment Patient Specific Quality Assurance and Gamma Index Variation Study in Gantry Dependent EPID Positions for IMRT Prostate Treatments

    Directory of Open Access Journals (Sweden)

    Siji Cyriac

    2014-01-01

    Full Text Available Pretreatment quality assurance (QA is a major concern in complex radiation therapy treatment plans like intensity modulated radiation therapy (IMRT. Present study considers the variations in gamma index for gantry dependent pretreatment verification and commonly practiced zero gantry angle verifications for ten prostate IMRT plans using two commercial medical linear accelerators (Varian 2300 CD, Varian Clinac iX. Two verification plans (the one with all fields at the actual treatment angles and one with all fields merged to 0 degree gantry angles for all the patients were generated to obtain dose fluence mapping using amorphous silicon electronic portal imaging device (EPID. The gamma index was found depend on gantry angles but the difference between zero and the nonzero treatment angles is in the confidence level for clinical acceptance. The acceptance criteria of gamma method were always satisfied in both cases for two machines and are stable enough to execute the patient specific pretreatment quality assurance at 0 degree gantry angle for prostate IMRTs, where limited number of gantry angles are used.

  10. The effect of aneurismai-wall mechanical properties on patient-specific hemodynamic simulations: two clinical case reports

    Institute of Scientific and Technical Information of China (English)

    Jialiang Chen; Shengzhang Wang; Guanghong Ding; Xinjian Yang; Huiyan Li

    2009-01-01

    Hemodynamic factors such as the wall shear stress play an important role in the pathogenesis and treatment of cerebral aneurysms. In present study, we apply computational fluid-structure interaction analyses on cerebral aneurysms with two different constitutive relations for aneurismal wall in order to investigate the effect of the aneurismal wall mechanical properties on the simulation results. We carry out these analyses by using two patient-specific models of cerebral aneurysms of different sizes located in different branches of the circle of Willis. The models are constructed from 3D rotational angiography image data and blood flow dynamics is studied under physiologically representative waveform of inflow. From the patient models analyzed in this investigation, we find that the deformations of cerebral aneurysms are very small. But due to the nonlinear character of the Navier-Stokes equations, these small deformations could have significant influences on the flow characteristics. In addition, we find that the aneurismal-wall mechanical properties have great effects on the deformation distribution of the aneurysm, which also affects the wall shear stress distribution and flow patterns. Therefore, how to define a proper constitutive relation for aneurismal wall should be considered carefully in the hemodynamic simulation.

  11. A Patient Specific Biomechanical Analysis of Custom Root Analogue Implant Designs on Alveolar Bone Stress: A Finite Element Study

    Directory of Open Access Journals (Sweden)

    David Anssari Moin

    2016-01-01

    Full Text Available Objectives. The aim of this study was to analyse by means of FEA the influence of 5 custom RAI designs on stress distribution of peri-implant bone and to evaluate the impact on microdisplacement for a specific patient case. Materials and Methods. A 3D surface model of a RAI for the upper right canine was constructed from the cone beam computed tomography data of one patient. Subsequently, five (targeted press-fit design modification FE models with five congruent bone models were designed: “Standard,” “Prism,” “Fins,” “Plug,” and “Bulbs,” respectively. Preprocessor software was applied to mesh the models. Two loads were applied: an oblique force (300 N and a vertical force (150 N. Analysis was performed to evaluate stress distributions and deformed contact separation at the peri-implant region. Results. The lowest von Mises stress levels were numerically observed for the Plug design. The lowest levels of contact separation were measured in the Fins model followed by the Bulbs design. Conclusions. Within the limitations of the applied methodology, adding targeted press-fit geometry to the RAI standard design will have a positive effect on stress distribution, lower concentration of bone stress, and will provide a better primary stability for this patient specific case.

  12. A comparative study of 1D and 3D hemodynamics in patient-specific hepatic portal vein networks

    Directory of Open Access Journals (Sweden)

    Jonášová A.

    2014-12-01

    Full Text Available The development of software for use in clinical practice is often associated with many requirements and restrictions set not only by the medical doctors, but also by the hospital’s budget. To meet the requirement of reliable software, which is able to provide results within a short time period and with minimal computational demand, a certain measure of modelling simplification is usually inevitable. In case of blood flow simulations carried out in large vascular networks such as the one created by the hepatic portal vein, simplifications are made by necessity. The most often employed simplification includes the approach in the form of dimensional reduction, when the 3D model of a large vascular network is substituted with its 1D counterpart. In this context, a question naturally arises, how this reduction can affect the simulation accuracy and its outcome. In this paper, we try to answer this question by performing a quantitative comparison of 3D and 1D flow models in two patient-specific hepatic portal vein networks. The numerical simulations are carried out under average flow conditions and with the application of the three-element Windkessel model, which is able to approximate the downstream flow resistance of real hepatic tissue. The obtained results show that, although the 1D model can never truly substitute the 3D model, its easy implementation, time-saving model preparation and almost no demands on computer technology dominate as advantages over obvious but moderate modelling errors arising from the performed dimensional reduction.

  13. Patient-specific simulation of a trileaflet aortic heart valve in a realistic left ventricle and aorta

    Science.gov (United States)

    Gilmanov, Anvar; Le, Trung; Stolarski, Henryk; Sotiropoulos, Fotis

    2013-11-01

    We develop a patient-specific model of the left ventricle consisting of: (1) magnetic-resonance images (MRI) data for wall geometry and kinematics reconstruction of the left ventricle during one cardiac cycle and (2) an elastic trileaflet aortic heart valve implanted in (3) a realistic aorta interacting with blood flow driven by the pulsating left ventricle. Blood flow is simulated via a new fluid-structure interaction (FSI) method, which couples the sharp-interface CURVIB [L. Ge, F. Sotiropoulos, JCP, (2007)] for handling complex moving boundaries with a new, rotation-free finite-element (FE) formulation for simulating large tissue deformations [H. Stolarski, A. Gilmanov, F. Sotiropoulos, IJNME, (2013)] The new FE shell formulation has been extensively tested and validated for a range of relevant problems showing good agreements. Validation of the coupled FSI-FE-CURVIB model is carried out for a thin plate undergoing flow-induced vibrations in the wake of a square cylinder and the computed results are in good agreement with published data. The new approach has been applied to simulate dynamic interaction of a trileaflet aortic heart valve with pulsating blood flow at physiological conditions and realistic artery and left ventricle geometry.

  14. Automated identification of brain tumours from single MR images based on segmentation with refined patient-specific priors

    Directory of Open Access Journals (Sweden)

    Ana eSanjuán

    2013-12-01

    Full Text Available Brain tumours can have different shapes or locations, making their identification very challenging. In functional MRI, it is not unusual that patients have only one anatomical image due to time and financial constraints. Here, we provide a modified automatic lesion identification (ALI procedure which enables brain tumour identification from single MR images. Our method rests on (A a modified segmentation-normalisation procedure with an explicit extra prior for the tumour and (B an outlier detection procedure for abnormal voxel (i.e. tumour classification. To minimise tissue misclassification, the segmentation-normalisation procedure requires prior information of the tumour location and extent. We therefore propose that ALI is run iteratively so that the output of Step B is used as a patient-specific prior in Step A. We test this procedure on real T1-weighted images from 18 patients, and the results were validated in comparison to two independent observers’ manual tracings. The automated procedure identified the tumours successfully with an excellent agreement with the manual segmentation (area under the ROC curve = 0.97 ± 0.03. The proposed procedure increases the flexibility and robustness of the ALI tool and will be particularly useful for lesion-behaviour mapping studies, or when lesion identification and/or spatial normalisation are problematic.

  15. Patient-specific quantification of respiratory motion-induced dose uncertainty for step-and-shoot IMRT of lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Li, Heng; Park, Peter; Liu, Wei; Matney, Jason; Balter, Peter; Zhang, Xiaodong; Li, Xiaoqiang; Zhu, X. Ronald [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Liao, Zhongxing [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Li, Yupeng [Applied Research, Varian Medical Systems, Palo Alto, California 94304 (United States)

    2013-12-15

    Purpose: The objective of this study was to quantify respiratory motion-induced dose uncertainty at the planning stage for step-and-shoot intensity-modulated radiation therapy (IMRT) using an analytical technique.Methods: Ten patients with stage II/III lung cancer who had undergone a planning four-dimensional (4D) computed tomographic scan and step-and-shoot IMRT planning were selected with a mix of motion and tumor size for this retrospective study. A step-and-shoot IMRT plan was generated for each patient. The maximum and minimum doses with respiratory motion were calculated for each plan, and the mean deviation from the 4D dose was calculated, taking delivery time, fractionation, and patient breathing cycle into consideration.Results: For all patients evaluated in this study, the mean deviation from the 4D dose in the planning target volume (PTV) was <2.5%, with a standard deviation <1.2%, and maximum point dose variation from the 4D dose was <6.2% in the PTV assuming delivery dose rate of 200 MU/min and patient breathing cycle of 8 s. The motion-induced dose uncertainty is a function of motion, fractionation, MU (plan modulation), dose rate, and patient breathing cycle.Conclusions: Respiratory motion-induced dose uncertainty varies from patient to patient. Therefore, it is important to evaluate the dose uncertainty on a patient-specific basis, which could be useful for plan evaluation and treatment strategy determination for selected patients.

  16. Patient-specific modeling and analysis of dynamic behavior of individual sickle red blood cells under hypoxic conditions

    Science.gov (United States)

    Li, Xuejin; Du, E.; Li, Zhen; Tang, Yu-Hang; Lu, Lu; Dao, Ming; Karniadakis, George

    2015-11-01

    Sickle cell anemia is an inherited blood disorder exhibiting heterogeneous morphology and abnormal dynamics under hypoxic conditions. We developed a time-dependent cell model that is able to simulate the dynamic processes of repeated sickling and unsickling of red blood cells (RBCs) under physiological conditions. By using the kinetic cell model with parameters derived from patient-specific data, we present a mesoscopic computational study of the dynamic behavior of individual sickle RBCs flowing in a microfluidic channel with multiple microgates. We investigate how individual sickle RBCs behave differently from healthy ones in channel flow, and analyze the alteration of cellular behavior and response to single-cell capillary obstruction induced by cell rheologic rigidification and morphological change due to cell sickling under hypoxic conditions. We also simulate the flow dynamics of sickle RBCs treated with hydroxyurea (HU) and quantify the relative enhancement of hemodynamic performance of HU. This work was supported by the National Institutes of Health (NIH) Grant U01HL114476.

  17. Patient-specific quantification of respiratory motion-induced dose uncertainty for step-and-shoot IMRT of lung cancer

    International Nuclear Information System (INIS)

    Purpose: The objective of this study was to quantify respiratory motion-induced dose uncertainty at the planning stage for step-and-shoot intensity-modulated radiation therapy (IMRT) using an analytical technique.Methods: Ten patients with stage II/III lung cancer who had undergone a planning four-dimensional (4D) computed tomographic scan and step-and-shoot IMRT planning were selected with a mix of motion and tumor size for this retrospective study. A step-and-shoot IMRT plan was generated for each patient. The maximum and minimum doses with respiratory motion were calculated for each plan, and the mean deviation from the 4D dose was calculated, taking delivery time, fractionation, and patient breathing cycle into consideration.Results: For all patients evaluated in this study, the mean deviation from the 4D dose in the planning target volume (PTV) was <2.5%, with a standard deviation <1.2%, and maximum point dose variation from the 4D dose was <6.2% in the PTV assuming delivery dose rate of 200 MU/min and patient breathing cycle of 8 s. The motion-induced dose uncertainty is a function of motion, fractionation, MU (plan modulation), dose rate, and patient breathing cycle.Conclusions: Respiratory motion-induced dose uncertainty varies from patient to patient. Therefore, it is important to evaluate the dose uncertainty on a patient-specific basis, which could be useful for plan evaluation and treatment strategy determination for selected patients

  18. Towards personalised management of atherosclerosis via computational models in vascular clinics: technology based on patient-specific simulation approach.

    Science.gov (United States)

    Díaz-Zuccarini, Vanessa; Di Tomaso, Giulia; Agu, Obiekezie; Pichardo-Almarza, Cesar

    2014-01-01

    The development of a new technology based on patient-specific modelling for personalised healthcare in the case of atherosclerosis is presented. Atherosclerosis is the main cause of death in the world and it has become a burden on clinical services as it manifests itself in many diverse forms, such as coronary artery disease, cerebrovascular disease/stroke and peripheral arterial disease. It is also a multifactorial, chronic and systemic process that lasts for a lifetime, putting enormous financial and clinical pressure on national health systems. In this Letter, the postulate is that the development of new technologies for healthcare using computer simulations can, in the future, be developed as in-silico management and support systems. These new technologies will be based on predictive models (including the integration of observations, theories and predictions across a range of temporal and spatial scales, scientific disciplines, key risk factors and anatomical sub-systems) combined with digital patient data and visualisation tools. Although the problem is extremely complex, a simulation workflow and an exemplar application of this type of technology for clinical use is presented, which is currently being developed by a multidisciplinary team following the requirements and constraints of the Vascular Service Unit at the University College Hospital, London.

  19. Patient-specific analysis of post-operative aortic hemodynamics: a focus on thoracic endovascular repair (TEVAR)

    Science.gov (United States)

    Auricchio, F.; Conti, M.; Lefieux, A.; Morganti, S.; Reali, A.; Sardanelli, F.; Secchi, F.; Trimarchi, S.; Veneziani, A.

    2014-10-01

    The purpose of this study is to quantitatively evaluate the impact of endovascular repair on aortic hemodynamics. The study addresses the assessment of post-operative hemodynamic conditions of a real clinical case through patient-specific analysis, combining accurate medical image analysis and advanced computational fluid-dynamics (CFD). Although the main clinical concern was firstly directed to the endoluminal protrusion of the prosthesis, the CFD simulations have demonstrated that there are two other important areas where the local hemodynamics is impaired and a disturbed blood flow is present: the first one is the ostium of the subclavian artery, which is partially closed by the graft; the second one is the stenosis of the distal thoracic aorta. Besides the clinical relevance of these specific findings, this study highlights how CFD analyses allow to observe important flow effects resulting from the specific features of patient vessel geometries. Consequently, our results demonstrate the potential impact of computational biomechanics not only on the basic knowledge of physiopathology, but also on the clinical practice, thanks to a quantitative extraction of knowledge made possible by merging medical data and mathematical models.

  20. Patient-specific computational analysis of the influence of a stent on the unsteady flow in cerebral aneurysms

    Science.gov (United States)

    Takizawa, Kenji; Schjodt, Kathleen; Puntel, Anthony; Kostov, Nikolay; Tezduyar, Tayfun E.

    2013-06-01

    We present a patient-specific computational analysis of the influence of a stent on the unsteady flow in cerebral aneurysms. The analysis is based on four different arterial models extracted form medical images, and the stent is placed across the neck of the aneurysm to reduce the flow circulation in the aneurysm. The core computational technique used in the analysis is the space-time (ST) version of the variational multiscale (VMS) method and is called "DSD/SST-VMST". The special techniques developed for this class of cardiovascular fluid mechanics computations are used in conjunction with the DSD/SST-VMST technique. The special techniques include NURBS representation of the surface over which the stent model and mesh are built, mesh generation with a reasonable resolution across the width of the stent wire and with refined layers of mesh near the arterial and stent surfaces, modeling the double-stent case, and quantitative assessment of the flow circulation in the aneurysm. We provide a brief overview of the special techniques, compute the unsteady flow patterns in the aneurysm for the four arterial models, and investigate in each case how those patterns are influenced by the presence of single and double stents.

  1. Automatic 4D reconstruction of patient-specific cardiac mesh with 1-to-1 vertex correspondence from segmented contours lines.

    Directory of Open Access Journals (Sweden)

    Chi Wan Lim

    Full Text Available We propose an automatic algorithm for the reconstruction of patient-specific cardiac mesh models with 1-to-1 vertex correspondence. In this framework, a series of 3D meshes depicting the endocardial surface of the heart at each time step is constructed, based on a set of border delineated magnetic resonance imaging (MRI data of the whole cardiac cycle. The key contribution in this work involves a novel reconstruction technique to generate a 4D (i.e., spatial-temporal model of the heart with 1-to-1 vertex mapping throughout the time frames. The reconstructed 3D model from the first time step is used as a base template model and then deformed to fit the segmented contours from the subsequent time steps. A method to determine a tree-based connectivity relationship is proposed to ensure robust mapping during mesh deformation. The novel feature is the ability to handle intra- and inter-frame 2D topology changes of the contours, which manifests as a series of merging and splitting of contours when the images are viewed either in a spatial or temporal sequence. Our algorithm has been tested on five acquisitions of cardiac MRI and can successfully reconstruct the full 4D heart model in around 30 minutes per subject. The generated 4D heart model conforms very well with the input segmented contours and the mesh element shape is of reasonably good quality. The work is important in the support of downstream computational simulation activities.

  2. Sound speed based patient-specific biomechanical modeling for registration of USCT volumes with X-ray mammograms

    Science.gov (United States)

    Hopp, T.; Stromboni, A.; Duric, N.; Zapf, M.; Gemmeke, H.; Ruiter, N. V.

    2013-03-01

    Ultrasound Computer Tomography is an upcoming imaging modality for early breast cancer detection. For evaluation of the method, comparison with the standard method X-ray mammography is of strongest interest. To overcome the significant differences in dimensionality and compression state of the breast, in earlier work a registration method based on biomechanical modeling of the breast was proposed. However only homogeneous models could be applied, i.e. inner structures of the breast were neglected. In this work we extend the biomechanical modeling of the breast by estimating patient-specific tissue parameters automatically from the speed of sound volume. Two heterogeneous models are proposed modeling a quadratic and an exponential relationship between speed of sound and tissue stiffness. The models were evaluated using phantom images and clinical data. The size of all lesions is better preserved using heterogeneous models, especially using an exponential relationship. The presented approach yields promising results and gives a physical justification to our registration method. It can be considered as a first step towards a realistic modeling of the breast.

  3. Pretreatment Patient Specific Quality Assurance and Gamma Index Variation Study in Gantry Dependent EPID Positions for IMRT Prostate Treatments

    International Nuclear Information System (INIS)

    Pretreatment quality assurance (QA) is a major concern in complex radiation therapy treatment plans like intensity modulated radiation therapy (IMRT). Present study considers the variations in gamma index for gantry dependent pretreatment verification and commonly practiced zero gantry angle verifications for ten prostate IMRT plans using two commercial medical linear accelerators (Varian 2300 CD, Varian Clinac iX). Two verification plans (the one with all fields at the actual treatment angles and one with all fields merged to 0 degree gantry angles) for all the patients were generated to obtain dose fluence mapping using amorphous silicon electronic portal imaging device (EPID). The gamma index was found depend on gantry angles but the difference between zero and the nonzero treatment angles is in the confidence level for clinical acceptance. The acceptance criteria of gamma method were always satisfied in both cases for two machines and are stable enough to execute the patient specific pretreatment quality assurance at 0 degree gantry angle for prostate IMRTs, where limited number of gantry angles are used.

  4. Computational Modelling of Multi-folded Balloon Delivery Systems for Coronary Artery Stenting: Insights into Patient-Specific Stent Malapposition.

    Science.gov (United States)

    Ragkousis, Georgios E; Curzen, Nick; Bressloff, Neil W

    2015-08-01

    Despite the clinical effectiveness of coronary artery stenting, percutaneous coronary intervention or "stenting" is not free of complications. Stent malapposition (SM) is a common feature of "stenting" particularly in challenging anatomy, such as that characterized by long, tortuous and bifurcated segments. SM is an important risk factor for stent thrombosis and recently it has been associated with longitudinal stent deformation. SM is the result of many factors including reference diameter, vessel tapering, the deployment pressure and the eccentric anatomy of the vessel. For the purpose of the present paper, virtual multi-folded balloon models have been developed for simulated deployment in both constant and varying diameter vessels under uniform pressure. The virtual balloons have been compared to available compliance charts to ensure realistic inflation response at nominal pressures. Thereafter, patient-specific simulations of stenting have been conducted aiming to reduce SM. Different scalar indicators, which allow a more global quantitative judgement of the mechanical performance of each delivery system, have been implemented. The results indicate that at constant pressure, the proposed balloon models can increase the minimum stent lumen area and thereby significantly decrease SM.

  5. Hearing Aid and children

    Directory of Open Access Journals (Sweden)

    Jamileh Fatahi

    2002-07-01

    Full Text Available In order to develop oral communication, hearing impaired infants and young children must be able to hear speech comfortably and consistently. To day children with all degrees of hearing loss may be condidates for some kinds of amlification. As children differ from adults, many Factors should be consider in hearing aid selection, evaluation and fitting. For example the child age when he or she is candidate for custom instruments? Do we consider programmable Hearing aid? Are multi memory instruments appropriate for them? What about directional microphones? What style of hearing aid do we select? In this paper such questions are Answered.

  6. Aid and Growth

    DEFF Research Database (Denmark)

    Mekasha, Tseday Jemaneh; Tarp, Finn

    Some recent literature in the meta-analysis category where results from a range of studies are brought together throws doubt on the ability of foreign aid to foster economic growth and development. This paper assesses what meta-analysis has to say about the effectiveness of foreign aid in terms...... of the growth impact. We re-examine key hypotheses, and find that the effect of aid on growth is positive and statistically significant. This significant effect is genuine, and not an artefact of publication selection. We also show why our results differ from those published elsewhere....

  7. Aid and Growth

    DEFF Research Database (Denmark)

    Tarp, Finn; Mekasha, Tseday Jemaneh

    2013-01-01

    Recent litterature in the meta-analysis category where results from a range of studies are brought together throws doubt on the ability of foreign aid to foster economic growth and development. This article assesses what meta-analysis has to contribute to the litterature on the effectiveness...... of foreign aid in terms of growth impact. We re-examine key hypotheses, and find that the effect of aid on growth is positive and statistically significant. This significant effect is genuine, and not an artefact of publication selection. We also show why our results differ from those published elsewhere....

  8. Aid and sectoral growth

    DEFF Research Database (Denmark)

    Selaya, Pablo; Thiele, Rainer

    2010-01-01

    This article examines empirically the proposition that aid to poor countries is detrimental for external competitiveness, giving rise to Dutch disease type effects. At the aggregate level, aid is found to have a positive effect on growth. A sectoral decomposition shows that the effect is (i......) significant and positive in the tradable and the nontradable sectors, and (ii) equally strong in both sectors. The article thus provides no empirical support for the hypothesis that aid reduces external competitiveness in developing countries. A possible reason for this finding is the existence of large idle...

  9. Aid Supplies Over Time

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    2015-01-01

    What determines how much foreign aid donors provide? Existing answers to this question point to a complex range of influences. However, the tasks of distinguishing between long- and short-run factors, as well as differences between donors, have not been adequately addressed. Taking advantage...... of data spanning nearly 50 years, this paper uses panel cointegration techniques to consider these issues. The analysis provides clear evidence for heterogeneity both between donors and over time, bandwagon effects, and a growing influence of security considerations in aid provision. Domestic...... macroeconomic shocks have a moderate but delayed effect on aid disbursements....

  10. Pulmonary complications of AIDS: radiologic features. [AIDS

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B.A.; Pomeranz, S.; Rabinowitz, J.G.; Rosen, M.J.; Train, J.S.; Norton, K.I.; Mendelson, D.S.

    1984-07-01

    Fifty-two patients with pulmonary complications of acquired immunodeficiency syndrome (AIDS) were studied over a 3-year period. The vast majority of the patients were homosexual; however, a significant number were intravenous drug abusers. Thirteen different organisms were noted, of which Pneumocystis carinii was by far the most common. Five patients had neoplasia. Most patients had initial abnormal chest films; however, eight patients subsequently shown to have Pneumocystis carinii pneumonia had normal chest films. A significant overlap in chest radiographic findings was noted among patients with different or multiple organisms. Lung biopsy should be an early consideration for all patients with a clinical history consistent with the pulmonary complications of AIDS. Of the 52 patients, 41 had died by the time this report was completed.

  11. Revision Knee Surgery

    Medline Plus

    Full Text Available Revision Knee Surgery Featuring the Zimmer® NexGen® LCCK System. Zimmer, Inc. Indio, California March 31, 2010 Welcome to this ... surgery, demonstrating the role of the NexGen LCCK Knee Revision System. If we could go to the ...

  12. [Cognitive deterioration after surgery

    DEFF Research Database (Denmark)

    Steinmetz, J.; Rasmussen, L.S.

    2008-01-01

    Delirium and postoperative cognitive dysfunction are important and common complications after surgery. Risk factors are first of all increasing age and type of surgery, whereas the type of anaesthesia does not seem to play an important role. Mortality is higher among patients with cognitive...

  13. Biliary tree and cholecyst: post surgery imaging

    Energy Technology Data Exchange (ETDEWEB)

    Valek, Vlastimil [Department of Radiology, University Hopistal Brno, Jihlavska 20, 63900 Brno (Czech Republic)]. E-mail: v.valek@fnrbno.cz; Kala, Zdenek [Department of Surgery, University Hospital Brno, Jihlavska 20, 63900 Brno (Czech Republic); Kysela, Petr [Department of Surgery, University Hospital Brno, Jihlavska 20, 63900 Brno (Czech Republic)

    2005-03-01

    Recently, with improvements in surgical techniques there has been a substantial reduction in the incidence of biliary complications of hepatobiliary surgery. Nevertheless, bile duct injuries and other post-cholecystectomy complications are a serious problem and a major cause of morbidity and mortality. Early complications may include bile duct injury caused by mistakenly placed clips, erroneous cutting of bile ducts based on misinterpretation of biliary anatomy, periductal bile leakage that causes edema, fibrosis and secondary stricturing, and ischemia due to injury to the right hepatic artery. Bile duct strictures are the most common of the late complications and can develop a few months or many years after surgery. Early detection and accurate diagnosis have a fundamental importance for the successful treatment of these complications. Therefore, early and meaningful application of the imaging methods immediately after detection of the first symptoms is essential. Peroperative ultrasound and direct iodine contrast application into the biliary tree (operative cholangiography) are highly important for immediate visualization of the complications during surgery. Ultrasound can be used to aid in identification of ductal structures and the cholangiogram should be obtained to document the anatomy. Plain abdominal film could be made in the patients in poor clinical conditions after biliary surgery. Oral cholecystography has largely been replaced by ultrasonography (US) for evaluation of cholelithiasis and complications like post-cholecystectomy fluid collections. The same methodology replaced the conventional intravenous cholangiography. Nowadays computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiography (MRCP) and ultrasound (US) have essential roles as primary imaging modalities after biliary tree and gallbladder surgery in the evaluation of associated complications and residual biliary stones. We review the role

  14. Factors influencing intraoperative blood loss in orthognathic surgery.

    Science.gov (United States)

    Thastum, M; Andersen, K; Rude, K; Nørholt, S E; Blomlöf, J

    2016-09-01

    This retrospective study aimed to identify factors of importance for intraoperative blood loss relative to total blood volume in patients undergoing orthognathic surgery. The study included 356 patients treated consecutively at a Danish university hospital between 1 January 2010 and 31 December 2012. Inclusion criteria were (1) patient age ≥18 years and (2) patient undergoing a three-piece Le Fort I osteotomy, a bilateral sagittal split osteotomy, or a combination of the two. The patient-specific relative blood loss was calculated as a percentage by dividing the intraoperative blood loss by the estimated preoperative total blood volume, and then correlated with body mass index (BMI), age, sex, operating time, and treatment modality in a multivariate stepwise regression analysis. Operating time (Psurgery, a prolonged operating time, and reduced BMI significantly increase the intraoperative relative blood loss in patients undergoing orthognathic surgery.

  15. Less extensive surgery compared to extensive surgery

    DEFF Research Database (Denmark)

    Lauszus, Finn F; Petersen, Astrid C; Neumann, Gudrun;

    2014-01-01

    -up by hospital data files, general practitioner, death certificate, and autopsy report. Revision of histopathology by a single pathologist. Main outcome measures: Survival and relapse by clinical data, stage, and type of surgery. RESULTS: The incidence of AGCT was 1.37 per year per 100,000 women (95% CI: 1.08, 1...

  16. Buying a Hearing Aid

    Science.gov (United States)

    ... Treatments & Cures Buying a Hearing Aid Cancer Treatment Scams Cancer Treatment Scams CURE-ious Bookmark Direct-to-Consumer Genetic Tests ... Money Privacy, Identity & Online Security Blog Video & Media Scam Alerts Get health and fitness updates by email ...

  17. HIV/AIDS

    Science.gov (United States)

    HIV stands for human immunodeficiency virus. It harms your immune system by destroying the white blood cells ... It is the final stage of infection with HIV. Not everyone with HIV develops AIDS. HIV most ...

  18. World AIDS Day 1998.

    Science.gov (United States)

    1999-01-01

    Excerpts of speeches given at a public rally on World AIDS Day 1998 underscore the need to energize support for those living with HIV/AIDS, emphasize the importance of increasing public education efforts, and memorialize those lost to the disease. Reverend Pat Bumgardner stressed the need to educate children about practicing safe sex and the dangers of drug use. He also focused attention on AIDS as a worldwide crisis, with the 30 million people who have HIV or AIDS. Councilwoman Margarita Lopez spoke about achieving objectives and securing resources through activism. She also condemned New York City's Mayor for trying to hinder the rally. Anne Chelimsky, who did not speak at the rally but attended it, reflected on her new role as an activist, and on how the rally affected her. PMID:11367196

  19. AidData

    Data.gov (United States)

    US Agency for International Development — AidData is a research and innovation lab making information on development finance more accessible and actionable. Tracking more than $6 trillion dollars from 90+...

  20. Tests and visits before surgery

    Science.gov (United States)

    Before surgery - tests; Before surgery - doctor visits ... Pre-op is the time before your surgery. It means "before operation." During this time, you will meet with one of your doctors. This may be your surgeon or primary care ...

  1. Chagas' disease and AIDS

    OpenAIRE

    Vaidian, Anil K; Louis M Weiss; Tanowitz, Herbert B.

    2004-01-01

    Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic ar...

  2. Hearing aid adjustment

    DEFF Research Database (Denmark)

    Heinemann, Trine; Matthews, Ben; Raudaskoski, Pirkko Liisa

    2012-01-01

    to the interaction during hearing aid fitting. This report of a Danish pilot study describes two such problems. The first problem arises from the requirement that the audiologist needs to ‘translate’ the patient’s subjective hearing description for making technological decisions. The second problem is the way...... in which the hearing aid user’s implicit and often unrealistic expectations are handled. This kind of research has potential application for developing a model of best practices....

  3. World AIDS Day 2004

    Institute of Scientific and Technical Information of China (English)

    CynthiaKirk; 刘保行

    2005-01-01

    December first was World AIDS Day. Last year, the campaign (运动;活动) centered on women and girls. They made up almost half of all people infected with the virus HIV that causes AIDS. And H1V was spreading faster among women than men in most areas of the world. These findings (发现) werefrom the yearly report by the United Nations and the World Health Organization, a UN agency

  4. Cognitive tools pipeline for assistance of mitral valve surgery

    Science.gov (United States)

    Schoch, Nicolai; Philipp, Patrick; Weller, Tobias; Engelhardt, Sandy; Volovyk, Mykola; Fetzer, Andreas; Nolden, Marco; De Simone, Raffaele; Wolf, Ivo; Maleshkova, Maria; Rettinger, Achim; Studer, Rudi; Heuveline, Vincent

    2016-03-01

    For cardiac surgeons, mitral valve reconstruction (MVR) surgery is a highly demanding procedure, where an artificial annuloplasty ring is implanted onto the mitral valve annulus to re-enable the valve's proper closing functionality. For a successful operation the surgeon has to keep track of a variety of relevant impact factors, such as patient-individual medical history records, valve geometries, or tissue properties of the surgical target, and thereon-based deduce type and size of the best-suitable ring prosthesis according to practical surgery experience. With this work, we aim at supporting the surgeon in selecting this ring prosthesis by means of a comprehensive information processing pipeline. It gathers all available patient-individual information, and mines this data according to 'surgical rules', that represent published MVR expert knowledge and recommended best practices, in order to suggest a set of potentially suitable annuloplasty rings. Subsequently, these rings are employed in biomechanical MVR simulation scenarios, which simulate the behavior of the patient-specific mitral valve subjected to the respective virtual ring implantation. We present the implementation of our deductive system for MVR ring selection and how it is integrated into a cognitive data processing pipeline architecture, which is built under consideration of Linked Data principles in order to facilitate holistic information processing of heterogeneous medical data. By the example of MVR surgery, we demonstrate the ease of use and the applicability of our development. We expect to essentially support patient-specific decision making in MVR surgery by means of this holistic information processing approach.

  5. The Plastic Surgery Compass: Navigating the Reconstructive Ladder in the Personalized Health Care Era

    Science.gov (United States)

    2016-01-01

    Summary: The reconstructive ladder and the reconstructive elevator have withstood the test of time as didactic tools for resident education. Over time, many alternative models have been suggested to incorporate the technological advances in plastic surgery, but none of them have focused on the patient. Changes in practice and the trend toward personalized health care demand a 360-degree evaluation and solution of surgical problems incorporating patient-specific characteristics. We, therefore, suggest the concept of the plastic surgery compass to navigate the ladder. PMID:27757348

  6. Stereo-particle image velocimetry measurements of a patient-specific Fontan physiology utilizing novel pressure augmentation stents.

    Science.gov (United States)

    Chopski, Steven G; Rangus, Owen M; Fox, Carson S; Moskowitz, William B; Throckmorton, Amy L

    2015-03-01

    Single ventricle anomalies are a challenging set of congenital heart defects that require lifelong clinical management due to progressive decline of cardiovascular function. Few therapeutic devices are available for these patients, and conventional blood pumps are not designed for the unique anatomy of the single ventricle physiology. To address this unmet need, we are developing an axial flow blood pump with a protective cage or stent for Fontan patients. This study investigates the 3-D particle image velocimetry measurements of two cage designs being deployed in a patient-specific Fontan anatomy. We considered a control case without a pump, impeller placed in the inferior vena cava, and two cases where the impeller has two protective stents with unique geometric characteristics. The experiments were evaluated at a cardiac output of 3 L/min, a fixed vena caval flow split of 40%/60%, a fixed pulmonary arterial flow split of 50%/50%, and for operating speeds of 1000-4000 rpm. The introduction of the cardiovascular stents had a substantial impact on the flow conditions leaving the pump and entering the cavopulmonary circulation. The findings indicated that rotational speeds above 4000 rpm for this pump could result in irregular flows in this specific circulatory condition. Although retrograde flow into the superior vena cava was not measured, the risk of this occurrence increases with higher pump speeds. The against-with stent geometry outperformed the other configurations by generating higher pressures and more energetic flows. These results provide further support for the viability of mechanical cavopulmonary assistance as a therapeutic treatment strategy for Fontan patients.

  7. Accuracy of CT-based patient-specific guides for total knee arthroplasty in patients with post-traumatic osteoarthritis.

    Science.gov (United States)

    Schotanus, M G M; van Haaren, E H; Hendrickx, R P M; Jansen, E J P; Kort, N P

    2015-12-01

    Published clinical trials who studied the accuracy of patient-specific guides (PSG) for total knee arthroplasty exclude patients with articular deformity of the knee joint. We prospectively analysed a series of 30 patients with post-traumatic osteoarthritis of the knee joint with use of PSG. At 1 year post-operative, the achieved biomechanical (HKA) axis and varus/valgus of the femur and tibia components were measured on anterior-posterior (AP) long-standing weight-bearing radiographs. Flexion/extension of the femoral and AP slope of the tibia component was measured on standard lateral radiographs. Percentages >3° deviation of the pre-operative planned HKA axis and individual implant components were considered as outliers. Approved and used implant size, median blood loss (ml) and operation time (min) were obtained from the operation records. Pre- and 1-year post-operative patient-reported outcome measures (PROMs) were performed. Eighty-three per cent of the patients had a HKA axis restored <3° of the pre-operative planned alignment. Varus/valgus outliers were 0.0 and 6.7 % for the femoral and tibial components, respectively. Percentages of outliers of flexion/extension were 36.7 % for the femoral component and 10.0 % for the AP slope of the tibial component. Median blood loss was 300 ml (50-700), while operation time was 67 min (44-144). In 20 % of all cases, the approved implant size was changed into one size smaller. One-year post-operative PROMs improved significantly. We conclude that the accuracy of CT-based PSG is not impaired in patients with post-traumatic osteoarthritis and this modality can restore biomechanical limb alignment. PMID:26265403

  8. Computerized tomography based “patient specific blocks” improve postoperative mechanical alignment in primary total knee arthroplasty

    Science.gov (United States)

    Vaishya, Raju; Vijay, Vipul; Birla, Vikas P; Agarwal, Amit K

    2016-01-01

    AIM: To compare the postoperative mechanical alignment achieved after total knee arthroplasty (TKA) using computer tomography (CT) based patient specific blocks (PSB) to conventional instruments (CI). METHODS: Total 80 knees were included in the study, with 40 knees in both the groups operated using PSB and CI. All the knees were performed by a single surgeon using the same cruciate sacrificing implants. In our study we used CT based PSB to compare with CI. Postoperative mechanical femoro-tibial angle (MFT angle) was measured on long leg x-rays using picture archiving and communication system (PACS). We compared mechanical alignment achieved using PSB and CI in TKA using statistical analysis. RESULTS: The PSB group (group 1) included 17 females and seven males while in CI group (group 2) there were 15 females and eight males. The mean age of patients in group 1 was 60.5 years and in group 2 it was 60.2 years. The mean postoperative MFT angle measured on long-leg radiographs in group 1 was 178.23° (SD = 2.67°, range: 171.9° to 182.5°) while in group 2, the mean MFT angle was 175.73° (SD = 3.62°, range: 166.0° to 179.8°). There was significant improvement in postoperative mechanical alignment (P value = 0.001), in PSB group compared to CI. Number of outliers were also found to be less in group operated with PSB (7 Knee) compared to those operated with CI (17 Knee). CONCLUSION: PSB improve mechanical alignment after total knee arthroplasty, compared to CI. This may lead to lower rates of revision in the PSB based TKA as compared to the conventional instrumentation.

  9. An approach for patient-specific multi-domain vascular mesh generation featuring spatially varying wall thickness modeling.

    Science.gov (United States)

    Raut, Samarth S; Liu, Peng; Finol, Ender A

    2015-07-16

    In this work, we present a computationally efficient image-derived volume mesh generation approach for vasculatures that implements spatially varying patient-specific wall thickness with a novel inward extrusion of the wall surface mesh. Multi-domain vascular meshes with arbitrary numbers, locations, and patterns of both iliac bifurcations and thrombi can be obtained without the need to specify features or landmark points as input. In addition, the mesh output is coordinate-frame independent and independent of the image grid resolution with high dimensional accuracy and mesh quality, devoid of errors typically found in off-the-shelf image-based model generation workflows. The absence of deformable template models or Cartesian grid-based methods enables the present approach to be sufficiently robust to handle aneurysmatic geometries with highly irregular shapes, arterial branches nearly parallel to the image plane, and variable wall thickness. The assessment of the methodology was based on i) estimation of the surface reconstruction accuracy, ii) validation of the output mesh using an aneurysm phantom, and iii) benchmarking the volume mesh quality against other frameworks. For the phantom image dataset (pixel size 0.105 mm; slice spacing 0.7 mm; and mean wall thickness 1.401±0.120 mm), the average wall thickness in the mesh was 1.459±0.123 mm. The absolute error in average wall thickness was 0.060±0.036 mm, or about 8.6% of the largest image grid spacing (0.7 mm) and 4.36% of the actual mean wall thickness. Mesh quality metrics and the ability to reproduce regional variations of wall thickness were found superior to similar alternative frameworks. PMID:25976018

  10. Determination of patient-specific internal gross tumor volumes for lung cancer using four-dimensional computed tomography

    International Nuclear Information System (INIS)

    To determine the optimal approach to delineating patient-specific internal gross target volumes (IGTV) from four-dimensional (4-D) computed tomography (CT) image data sets used in the planning of radiation treatment for lung cancers. We analyzed 4D-CT image data sets of 27 consecutive patients with non-small-cell lung cancer (stage I: 17, stage III: 10). The IGTV, defined to be the envelope of respiratory motion of the gross tumor volume in each 4D-CT data set was delineated manually using four techniques: (1) combining the gross tumor volume (GTV) contours from ten respiratory phases (IGTVAllPhases); (2) combining the GTV contours from two extreme respiratory phases (0% and 50%) (IGTV2Phases); (3) defining the GTV contour using the maximum intensity projection (MIP) (IGTVMIP); and (4) defining the GTV contour using the MIP with modification based on visual verification of contours in individual respiratory phase (IGTVMIP-Modified). Using the IGTVAllPhases as the optimum IGTV, we compared volumes, matching indices, and extent of target missing using the IGTVs based on the other three approaches. The IGTVMIP and IGTV2Phases were significantly smaller than the IGTVAllPhases (p < 0.006 for stage I and p < 0.002 for stage III). However, the values of the IGTVMIP-Modified were close to those determined from IGTVAllPhases (p = 0.08). IGTVMIP-Modified also matched the best with IGTVAllPhases. IGTVMIP and IGTV2Phases underestimate IGTVs. IGTVMIP-Modified is recommended to improve IGTV delineation in lung cancer

  11. Patient-specific induced pluripotent stem cells in neurological disease modeling: the importance of nonhuman primate models

    Directory of Open Access Journals (Sweden)

    Qiu Z

    2013-07-01

    Full Text Available Zhifang Qiu,1,2 Steven L Farnsworth,2 Anuja Mishra,1,2 Peter J Hornsby1,21Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, TX, USA; 2Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, TX, USAAbstract: The development of the technology for derivation of induced pluripotent stem (iPS cells from human patients and animal models has opened up new pathways to the better understanding of many human diseases, and has created new opportunities for therapeutic approaches. Here, we consider one important neurological disease, Parkinson's, the development of relevant neural cell lines for studying this disease, and the animal models that are available for testing the survival and function of the cells, following transplantation into the central nervous system. Rapid progress has been made recently in the application of protocols for neuroectoderm differentiation and neural patterning of pluripotent stem cells. These developments have resulted in the ability to produce large numbers of dopaminergic neurons with midbrain characteristics for further study. These cells have been shown to be functional in both rodent and nonhuman primate (NHP models of Parkinson's disease. Patient-specific iPS cells and derived dopaminergic neurons have been developed, in particular from patients with genetic causes of Parkinson's disease. For complete modeling of the disease, it is proposed that the introduction of genetic changes into NHP iPS cells, followed by studying the phenotype of the genetic change in cells transplanted into the NHP as host animal, will yield new insights into disease processes not possible with rodent models alone.Keywords: Parkinson's disease, pluripotent cell differentiation, neural cell lines, dopaminergic neurons, cell transplantation, animal models

  12. Blood flow dynamic improvement with aneurysm repair detected by a patient-specific model of multiple aortic aneurysms.

    Science.gov (United States)

    Sughimoto, Koichi; Takahara, Yoshiharu; Mogi, Kenji; Yamazaki, Kenji; Tsubota, Ken'ichi; Liang, Fuyou; Liu, Hao

    2014-05-01

    Aortic aneurysms may cause the turbulence of blood flow and result in the energy loss of the blood flow, while grafting of the dilated aorta may ameliorate these hemodynamic disturbances, contributing to the alleviation of the energy efficiency of blood flow delivery. However, evaluating of the energy efficiency of blood flow in an aortic aneurysm has been technically difficult to estimate and not comprehensively understood yet. We devised a multiscale computational biomechanical model, introducing novel flow indices, to investigate a single male patient with multiple aortic aneurysms. Preoperative levels of wall shear stress and oscillatory shear index (OSI) were elevated but declined after staged grafting procedures: OSI decreased from 0.280 to 0.257 (first operation) and 0.221 (second operation). Graftings may strategically counter the loss of efficient blood delivery to improve hemodynamics of the aorta. The energy efficiency of blood flow also improved postoperatively. Novel indices of pulsatile pressure index (PPI) and pulsatile energy loss index (PELI) were evaluated to characterize and quantify energy loss of pulsatile blood flow. Mean PPI decreased from 0.445 to 0.423 (first operation) and 0.359 (second operation), respectively; while the preoperative PELI of 0.986 dropped to 0.820 and 0.831. Graftings contributed not only to ameliorate wall shear stress or oscillatory shear index but also to improve efficient blood flow. This patient-specific modeling will help in analyzing the mechanism of aortic aneurysm formation and may play an important role in quantifying the energy efficiency or loss in blood delivery. PMID:23852404

  13. SU-F-BRF-01: A GPU Framework for Developing Interactive High-Resolution Patient-Specific Biomechanical Models

    International Nuclear Information System (INIS)

    Purpose: To develop a GPU-based framework that can generate highresolution and patient-specific biomechanical models from a given simulation CT and contoured structures, optimized to run at interactive speeds, for addressing adaptive radiotherapy objectives. Method: A Massspring-damping (MSD) model was generated from a given simulation CT. The model's mass elements were generated for every voxel of anatomy, and positioned in a deformation space in the GPU memory. MSD connections were established between neighboring mass elements in a dense distribution. Contoured internal structures allowed control over elastic material properties of different tissues. Once the model was initialized in GPU memory, skeletal anatomy was actuated using rigid-body transformations, while soft tissues were governed by elastic corrective forces and constraints, which included tensile forces, shear forces, and spring damping forces. The model was validated by applying a known load to a soft tissue block and comparing the observed deformation to ground truth calculations from established elastic mechanics. Results: Our analyses showed that both local and global load experiments yielded results with a correlation coefficient R2 > 0.98 compared to ground truth. Models were generated for several anatomical regions. Head and neck models accurately simulated posture changes by rotating the skeletal anatomy in three dimensions. Pelvic models were developed for realistic deformations for changes in bladder volume. Thoracic models demonstrated breast deformation due to gravity when changing treatment position from supine to prone. The GPU framework performed at greater than 30 iterations per second for over 1 million mass elements with up to 26 MSD connections each. Conclusions: Realistic simulations of site-specific, complex posture and physiological changes were simulated at interactive speeds using patient data. Incorporating such a model with live patient tracking would facilitate real

  14. Mechanical cavopulmonary assistance of a patient-specific Fontan physiology: numerical simulations, lumped parameter modeling, and suction experiments.

    Science.gov (United States)

    Throckmorton, Amy L; Carr, James P; Tahir, Sharjeel A; Tate, Ryan; Downs, Emily A; Bhavsar, Sonya S; Wu, Yi; Grizzard, John D; Moskowitz, William B

    2011-11-01

    This study investigated the performance of a magnetically levitated, intravascular axial flow blood pump for mechanical circulatory support of the thousands of Fontan patients in desperate need of a therapeutic alternative. Four models of the extracardiac, total cavopulmonary connection (TCPC) Fontan configuration were evaluated to formulate numerical predictions: an idealized TCPC, a patient-specific TCPC per magnetic resonance imaging data, and each of these two models having a blood pump in the inferior vena cava (IVC). A lumped parameter model of the Fontan physiology was used to specify boundary conditions. Pressure-flow characteristics, energy gain calculations, scalar stress levels, and blood damage estimations were executed for each model. Suction limitation experiments using the Sylgard elastomer tubing were also conducted. The pump produced pressures of 1-16 mm Hg for 2000-6000 rpm and flow rates of 0.5-4.5 L/min. The pump inlet or IVC pressure was found to decrease at higher rotational speeds. Maximum scalar stress estimations were 3 Pa for the nonpump models and 290 Pa for the pump-supported cases. The blood residence times for the pump-supported cases were shorter (0.9 s) as compared with the nonsupported configurations (2.5 s). However, the blood damage indices were higher (1.5%) for the anatomic model with pump support. The pump successfully augmented pressure in the TCPC junction and increased the hydraulic energy of the TCPC as a function of flow rate and rotational speed. The suction experiments revealed minimal deformation (<3%) at 9000 rpm. The findings of this study support the continued design and development of this blood pump.

  15. SU-F-BRE-08: Feasibility of 3D Printed Patient Specific Phantoms for IMRT/IGRT QA

    Energy Technology Data Exchange (ETDEWEB)

    Ehler, E; Higgins, P; Dusenbery, K [University of Minnesota, Minneapolis, MN (United States)

    2014-06-15

    Purpose: Test the feasibility of 3D printed, per-patient phantoms for IMRT QA to analyze the treatment delivery quality within the patient geometry. Methods: Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom. During the delivery of the IMRT QA on to the 3D printed phantom, the same patient positioning indexing system was used on the phantom and image guidance (cone beam CT) was used to localize the phantom, serving as a test of the IGRT system as well. The 3D printed phantom was designed to accommodate four radiochromic film planes (two axial, one coronal and one sagittal) and an ionization chamber measurement. As a frame of comparison, the IMRT QA was also performed on traditional phantoms. Dosimetric tolerance levels such as 3mm / 3% Gamma Index as well as 3% and 5% dose difference were considered. All detector systems were calibrated against a NIST traceable ionization chamber. Results: Comparison of results 3D printed patient phantom with the standard IMRT QA systems showed similar passing rates for the 3D printed phantom and the standard phantoms. However, the locations of the failing regions did not necessarily correlate. The 3D printed phantom was localized within 1 mm and 1° using on-board cone beam CT. Conclusion: A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine clinical use.

  16. SU-F-BRF-01: A GPU Framework for Developing Interactive High-Resolution Patient-Specific Biomechanical Models

    Energy Technology Data Exchange (ETDEWEB)

    Neylon, J; Qi, S; Sheng, K; Kupelian, P; Santhanam, A [UCLA School of Medicine, Los Angeles, CA (United States)

    2014-06-15

    Purpose: To develop a GPU-based framework that can generate highresolution and patient-specific biomechanical models from a given simulation CT and contoured structures, optimized to run at interactive speeds, for addressing adaptive radiotherapy objectives. Method: A Massspring-damping (MSD) model was generated from a given simulation CT. The model's mass elements were generated for every voxel of anatomy, and positioned in a deformation space in the GPU memory. MSD connections were established between neighboring mass elements in a dense distribution. Contoured internal structures allowed control over elastic material properties of different tissues. Once the model was initialized in GPU memory, skeletal anatomy was actuated using rigid-body transformations, while soft tissues were governed by elastic corrective forces and constraints, which included tensile forces, shear forces, and spring damping forces. The model was validated by applying a known load to a soft tissue block and comparing the observed deformation to ground truth calculations from established elastic mechanics. Results: Our analyses showed that both local and global load experiments yielded results with a correlation coefficient R{sup 2} > 0.98 compared to ground truth. Models were generated for several anatomical regions. Head and neck models accurately simulated posture changes by rotating the skeletal anatomy in three dimensions. Pelvic models were developed for realistic deformations for changes in bladder volume. Thoracic models demonstrated breast deformation due to gravity when changing treatment position from supine to prone. The GPU framework performed at greater than 30 iterations per second for over 1 million mass elements with up to 26 MSD connections each. Conclusions: Realistic simulations of site-specific, complex posture and physiological changes were simulated at interactive speeds using patient data. Incorporating such a model with live patient tracking would facilitate

  17. SU-F-BRE-08: Feasibility of 3D Printed Patient Specific Phantoms for IMRT/IGRT QA

    International Nuclear Information System (INIS)

    Purpose: Test the feasibility of 3D printed, per-patient phantoms for IMRT QA to analyze the treatment delivery quality within the patient geometry. Methods: Using the head and neck region of an anthropomorphic phantom as a substitute for an actual patient, a soft-tissue equivalent model was constructed with the use of a 3D printer. A nine-field IMRT plan was constructed and dose verification measurements were performed for the 3D printed phantom. During the delivery of the IMRT QA on to the 3D printed phantom, the same patient positioning indexing system was used on the phantom and image guidance (cone beam CT) was used to localize the phantom, serving as a test of the IGRT system as well. The 3D printed phantom was designed to accommodate four radiochromic film planes (two axial, one coronal and one sagittal) and an ionization chamber measurement. As a frame of comparison, the IMRT QA was also performed on traditional phantoms. Dosimetric tolerance levels such as 3mm / 3% Gamma Index as well as 3% and 5% dose difference were considered. All detector systems were calibrated against a NIST traceable ionization chamber. Results: Comparison of results 3D printed patient phantom with the standard IMRT QA systems showed similar passing rates for the 3D printed phantom and the standard phantoms. However, the locations of the failing regions did not necessarily correlate. The 3D printed phantom was localized within 1 mm and 1° using on-board cone beam CT. Conclusion: A custom phantom was created using a 3D printer. It was determined that the use of patient specific phantoms to perform dosimetric verification and estimate the dose in the patient is feasible. In addition, end-to-end testing on a per-patient basis was possible with the 3D printed phantom. Further refinement of the phantom construction process is needed for routine clinical use

  18. Multilateral Aid | L’aide multilatérale

    Directory of Open Access Journals (Sweden)

    2012-05-01

    Full Text Available Bilateral and Multilateral Aid, DAC Members, 1960–2010 (in million USD constant, 2009Aide bilatérale et multilatérale des pays membres du CAD, 1960-2010 (en millions USD constants de 2009­Bilateral and Multilateral Aid by Recipient Region, DAC Members, 2008 (in percentage of total aid by RegionAide bilatérale et multilatérale des pays membres du CAD par region de destination, 2008 (en pourcentage de l’aide totale par régionSources: OECD (2010 2010 DAC Report on Multilateral Aid (Paris: O...

  19. [Approach to the patient in the ambulatory surgery unit].

    Science.gov (United States)

    Cordero-Ponce, Montserrat; Romero-Sánchez, Isabel María; López-Barea, José; Martínez-Ramos, Pablo

    2008-01-01

    Ambulatory surgery aims to improve the quality of care, provide services in an environment closer to users' normal surroundings, reduce the risk of nosocomial infection and release hospital beds for other uses demanded by the population, thus reducing health costs. Nursing activity in these units should aim to restore health and aid the rapid recovery of patients in their homes. To achieve this, an effective health education program is required. Such programs should be simple and, at the same time, cover the care that these patients will require during the recovery period at home. The unit covers patients in the Virgen de Rocío University Hospital, The Fleming Peripheral Center for Specialties and the Virgen de los Reyes Peripheral Center for Specialties in Seville, Spain and the the specialties included are plastic surgery, otorhinolaryngology, orthopedic surgery, urology, and general surgery. The duration of the education program will be at most 14-17 h.

  20. 计算机辅助外科中手术与计划空间标定以及视觉空间的误差校正%Calibration Between Operation Space and Plan Space and Error Correction of Visual Space in Computer-aided Surgery

    Institute of Scientific and Technical Information of China (English)

    郭锥; 周宇; 席文明

    2012-01-01

    In computer-aided surgery (CAS) system,many space integrates in together,in order to improve the precision of the system operation,the effective calibration method to correct the error between the space is needed. Using the robot characteristics motion errors in visual space of navigation system to establish the mapping of visual space and robot space,and to recursion correction the local transformation matrix of visual space and robot space. Using local transformation matrix to establish optimization equatipn.and then obtaining global optimal transformation matrix. This method for all the static and dynamic error correction. According to the coupling error exists in the operation and plan space,using the designed special structure force sensor and calibration piece of decoupling to calibration its error, and according to the transformation matrix to adjust the objects position and orientation in the plan space to ensure that the objects in the plan space have the same pose with it in the operation space. The experimental results show that the dynamic calibration method can make the visual space global error reduced to 5 pixels,and the force control calibration method can make the position error is reduced to 0. 25 mm and the posture error reduced to 0. 1%计算机辅助外科(CAS)系统中,多空间集成在一起,为了提高系统的操作精度,需要有效的标定方法校正空间之间的误差.利用机器人上特征在导航系统中视觉空间的运动误差,建立视觉空间与机器人空间的映射关系,递归校正两空间之间的局部转换矩阵.利用局部转换矩阵建立优化方程,求取全局最优转换矩阵.该方法对所有动态、静态误差进行校正.针对手术与计划空间中存在的耦合误差,利用设计的特殊结构力传感器和标定块解耦标定其误差,并根据求取的转换矩阵,调整计划空间中对象的位姿,保证计划空间与手术空间中的对象位姿一致.实验结果表明,动