A comparison of Espocan and Tuohy needles for the combined spinal-epidural technique for labor analgesia.

PubMed

Browne, Ingrid M; Birnbach, David J; Stein, Deborah J; O'Gorman, David A; Kuroda, Maxine

2005-08-01

When using the needle-through-needle combined spinal-epidural (CSE) technique for labor analgesia, failure to obtain cerebrospinal fluid (CSF), paresthesias, and intrathecal or intravascular migration of the catheter are of concern. Epidural needles with spinal needle apertures, such as the back-hole Espocan (ES) needles, are available and may reduce these risks. We describe the efficacy and adverse events associated with a modified epidural needle (ES) versus a conventional Tuohy needle for CSE. One-hundred parturients requesting labor analgesia (CSE) were randomized into 2 groups: 50-ES 18-gauge modified epidural needle with 27-gauge Pencan atraumatic spinal needle, 50-conventional 18-gauge Tuohy needle with 27-gauge Gertie Marx atraumatic spinal needle. Information on intrathecal or intravascular catheter placement, paresthesia on introduction of spinal needle, failure to obtain CSF through the spinal needle after placement of epidural needle, unintentional dural puncture, and epidural catheter function was obtained. No intrathecal catheter placement occurred in either group. Rates of intravascular catheter placement and unintentional dural puncture were similar between the groups. Significant differences were noted regarding spinal needle-induced paresthesia (14% ES versus 42% Tuohy needles, P = 0.009) and failure to obtain CSF on first attempt (8% ES versus 28% Tuohy needles, P < 0.02). Use of ES needles for CSE significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt. The use of modified epidural needles with a back hole for combined spinal-epidural technique significantly reduces paresthesia associated with the insertion of the spinal needle and is associated with more frequent successful spinal needle placement on the first attempt.

Augmented Reality-Guided Lumbar Facet Joint Injections.

PubMed

Agten, Christoph A; Dennler, Cyrill; Rosskopf, Andrea B; Jaberg, Laurenz; Pfirrmann, Christian W A; Farshad, Mazda

2018-05-08

The aim of this study was to assess feasibility and accuracy of augmented reality-guided lumbar facet joint injections. A spine phantom completely embedded in hardened opaque agar with 3 ring markers was built. A 3-dimensional model of the phantom was uploaded to an augmented reality headset (Microsoft HoloLens). Two radiologists independently performed 20 augmented reality-guided and 20 computed tomography (CT)-guided facet joint injections each: for each augmented reality-guided injection, the hologram was manually aligned with the phantom container using the ring markers. The radiologists targeted the virtual facet joint and tried to place the needle tip in the holographic joint space. Computed tomography was performed after each needle placement to document final needle tip position. Time needed from grabbing the needle to final needle placement was measured for each simulated injection. An independent radiologist rated images of all needle placements in a randomized order blinded to modality (augmented reality vs CT) and performer as perfect, acceptable, incorrect, or unsafe. Accuracy and time to place needles were compared between augmented reality-guided and CT-guided facet joint injections. In total, 39/40 (97.5%) of augmented reality-guided needle placements were either perfect or acceptable compared with 40/40 (100%) CT-guided needle placements (P = 0.5). One augmented reality-guided injection missed the facet joint space by 2 mm. No unsafe needle placements occurred. Time to final needle placement was substantially faster with augmented reality guidance (mean 14 ± 6 seconds vs 39 ± 15 seconds, P < 0.001 for both readers). Augmented reality-guided facet joint injections are feasible and accurate without potentially harmful needle placement in an experimental setting.

Robotic Assistance for Ultrasound-Guided Prostate Brachytherapy

PubMed Central

Fichtinger, Gabor; Fiene, Jonathan P.; Kennedy, Christopher W.; Kronreif, Gernot; Iordachita, Iulian; Song, Danny Y.; Burdette, Everette C.; Kazanzides, Peter

2016-01-01

We present a robotically assisted prostate brachytherapy system and test results in training phantoms and Phase-I clinical trials. The system consists of a transrectal ultrasound (TRUS) and a spatially co-registered robot, fully integrated with an FDA-approved commercial treatment planning system. The salient feature of the system is a small parallel robot affixed to the mounting posts of the template. The robot replaces the template interchangeably, using the same coordinate system. Established clinical hardware, workflow and calibration remain intact. In all phantom experiments, we recorded the first insertion attempt without adjustment. All clinically relevant locations in the prostate were reached. Non-parallel needle trajectories were achieved. The pre-insertion transverse and rotational errors (measured with a Polaris optical tracker relative to the template’s coordinate frame) were 0.25mm (STD=0.17mm) and 0.75° (STD=0.37°). In phantoms, needle tip placement errors measured in TRUS were 1.04mm (STD=0.50mm). A Phase-I clinical feasibility and safety trial has been successfully completed with the system. We encountered needle tip positioning errors of a magnitude greater than 4mm in only 2 out of 179 robotically guided needles, in contrast to manual template guidance where errors of this magnitude are much more common. Further clinical trials are necessary to determine whether the apparent benefits of the robotic assistant will lead to improvements in clinical efficacy and outcomes. PMID:18650122

Development and validation of a new guidance device for lateral approach stereotactic breast biopsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, K.; Kornecki, A.; Bax, J.

2009-06-15

Stereotactic breast biopsy (SBB) is the gold standard for minimally invasive breast cancer diagnosis. Current systems rely on one of two methods for needle insertion: A vertical approach (perpendicular to the breast compression plate) or a lateral approach (parallel to the compression plate). While the vertical approach is more frequently used, it is not feasible in patients with thin breasts (<3 cm thick after compression) or with superficial lesions. Further, existing SBB guidance hardware provides at most one degree of rotational freedom in the needle trajectory, and as such requires a separate skin incision for each biopsy target. The authorsmore » present a new design of lateral guidance device for SBB, which addresses the limitations of the vertical approach and provides improvements over the existing lateral guidance hardware. Specifically, the new device provides (1) an adjustable rigid needle support to minimize needle deflection within the breast and (2) an additional degree of rotational freedom in the needle trajectory, allowing the radiologist to sample multiple targets through a single skin incision. This device was compared to a commercial lateral guidance device in a series of phantom experiments. Needle placement error using each device was measured in agar phantoms for needle insertions at lateral depths of 2 and 5 cm. The biopsy success rate for each device was then estimated by performing biopsy procedures in commercial SBB phantoms. SBB performed with the new lateral guidance device provided reduced needle placement error relative to the commercial lateral guidance device (0.89{+-}0.22 vs 1.75{+-}0.35 mm for targets at 2 cm depth; 1.94{+-}0.20 vs 3.21{+-}0.31 mm for targets at 5 cm depth). The new lateral guidance device also provided improved biopsy accuracy in SBB procedures compared to the commercial lateral guidance device (100% vs 58% success rate). Finally, experiments were performed to demonstrate that the new device can accurately sample lesions within thin breast phantoms and multiple lesions through a single incision point. This device can be incorporated directly into the clinical SBB procedural workflow, with no additional electrical hardware, software, postprocessing, or image analysis.« less

Comparison of CT Fluoroscopy-Guided Manual and CT-Guided Robotic Positioning System for In Vivo Needle Placements in Swine Liver

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cornelis, F.; Takaki, H.; Laskhmanan, M.

PurposeTo compare CT fluoroscopy-guided manual and CT-guided robotic positioning system (RPS)-assisted needle placement by experienced IR physicians to targets in swine liver.Materials and MethodsManual and RPS-assisted needle placement was performed by six experienced IR physicians to four 5 mm fiducial seeds placed in swine liver (n = 6). Placement performance was assessed for placement accuracy, procedure time, number of confirmatory scans, needle manipulations, and procedure radiation dose. Intra-modality difference in performance for each physician was assessed using paired t test. Inter-physician performance variation for each modality was analyzed using Kruskal–Wallis test.ResultsPaired comparison of manual and RPS-assisted placements to a target by the samemore » physician indicated accuracy outcomes was not statistically different (manual: 4.53 mm; RPS: 4.66 mm; p = 0.41), but manual placement resulted in higher total radiation dose (manual: 1075.77 mGy/cm; RPS: 636.4 mGy/cm; p = 0.03), required more confirmation scans (manual: 6.6; RPS: 1.6; p < 0.0001) and needle manipulations (manual: 4.6; RPS: 0.4; p < 0.0001). Procedure time for RPS was longer than manual placement (manual: 6.12 min; RPS: 9.7 min; p = 0.0003). Comparison of inter-physician performance during manual placement indicated significant differences in the time taken to complete placements (p = 0.008) and number of repositions (p = 0.04) but not in other study measures (p > 0.05). Comparison of inter-physician performance during RPS-assisted placement suggested statistically significant differences in procedure time (p = 0.02) and not in other study measures (p > 0.05).ConclusionsCT-guided RPS-assisted needle placement reduced radiation dose, number of confirmatory scans, and needle manipulations when compared to manual needle placement by experienced IR physicians, with equivalent accuracy.« less

Benefits of Ultrasound Imaging for Placement of Caudal Epidural Blockade in 3 Pediatric Patients: A Case Report.

PubMed

Sinskey, Jina L; Vecchione, Tricia M; Ekstrom, Benjamin G; Boretsky, Karen

2018-06-01

Pediatric caudal epidural blockade, the most common pediatric regional anesthetic, is classically placed using surface landmark technique with infrequent use of ultrasound guidance. We present 3 cases where ultrasound guidance facilitated successful placement and helped prevent complications. One infant had an unanticipated S5 dural sac necessitating needle redirection to avoid subarachnoid injection. A 5-year old had proper needle position with inability to inject secondary to needle blockage confirmed with ultrasound. An expremature infant had initial needle placement anterior to the sacrum with subsequent proper placement using real-time ultrasound imaging. Ultrasound guidance for pediatric caudal placement confers advantages and increased routine use should be considered.

First clinical use of the EchoTrack guidance approach for radiofrequency ablation of thyroid gland nodules.

PubMed

Franz, Alfred Michael; Seitel, Alexander; Bopp, Nasrin; Erbelding, Christian; Cheray, Dominique; Delorme, Stefan; Grünwald, Frank; Korkusuz, Hüdayi; Maier-Hein, Lena

2017-06-01

Percutaneous radiofrequency ablation (RFA) of thyroid nodules is an alternative to surgical resection that offers the benefits of minimal scars for the patient, lower complication rates, and shorter treatment times. Ultrasound (US) is the preferred modality for guiding these procedures. The needle is usually kept within the US scanning plane to ensure needle visibility. However, this restricts flexibility in both transducer and needle movement and renders the procedure difficult, especially for inexperienced users. Existing navigation solutions often involve electromagnetic (EM) tracking, which requires placement of an external field generator (FG) in close proximity of the intervention site in order to avoid distortion of the EM field. This complicates the clinical workflow as placing the FG while ensuring that it neither restricts the physician's workspace nor affects tracking accuracy is awkward and time-consuming. The EchoTrack concept overcomes these issues by combining the US probe and the EM FG in one modality, simultaneously providing both real-time US and tracking data without requiring the placement of an external FG for tracking. We propose a system and workflow to use EchoTrack for RFA of thyroid nodules. According to our results, the overall error of the EchoTrack system resulting from errors related to tracking and calibration is below 2 mm. Navigated thyroid RFA with the proposed concept is clinically feasible. Motion of internal critical structures relative to external markers can be up to several millimeters in extreme cases. The EchoTrack concept with its simple setup, flexibility, improved needle visualization, and additional guidance information has high potential to be clinically used for thyroid RFA.

Inheriting the Learner's View: A Google Glass-Based Wearable Computing Platform for Improving Surgical Trainee Performance.

PubMed

Brewer, Zachary E; Fann, Hutchinson C; Ogden, W David; Burdon, Thomas A; Sheikh, Ahmad Y

2016-01-01

It is speculated that, in operative environments, real-time visualization of the trainee's viewpoint by the instructor may improve performance and teaching efficacy. We hypothesized that introduction of a wearable surgical visualization system allowing the instructor to visualize otherwise "blind" areas in the operative field could improve trainee performance in a simulated operative setting. A total of 11 surgery residents (4 in general surgery training and 7 in an integrated 6-year cardiothoracic surgery program) participated in the study. Google (Mountain View, CA) Glass hardware running proprietary software from CrowdOptic (San Francisco, CA) was utilized for creation of the wearable surgical visualization system. Both the learner and trainer wore the system, and video was streamed from the learner's system in real time to the trainer, who directed the learner to place needles in a simulated operative field. Subjects placed a total of 5 needles in each of 4 quadrants. A composite error score was calculated based on the accuracy of needle placement in relation to the intended needle trajectories as described by the trainer. Time to task completion (TTC) was also measured and participants completed an exit questionnaire. All residents completed the protocol tasks and the survey. Introduction of the wearable surgical visualization system did not affect mean time to task completion (278 ± 50 vs. 282 ± 69 seconds, p = NS). However, mean composite error score fell significantly once the wearable system was deployed (18 ± 5 vs. 15 ± 4, p < 0.05), demonstrating improved accuracy of needle placement. Most of the participants deemed the device unobtrusive, easy to operate, and useful for communication and instruction. This study suggests that wearable surgical visualization systems allowing for adoption of the learner's perspective may be a useful educational adjunct in the training of surgeons. Further evaluations of the efficacy of wearable technology in the operating room environment are warranted. Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Target motion tracking in MRI-guided transrectal robotic prostate biopsy.

PubMed

Tadayyon, Hadi; Lasso, Andras; Kaushal, Aradhana; Guion, Peter; Fichtinger, Gabor

2011-11-01

MRI-guided prostate needle biopsy requires compensation for organ motion between target planning and needle placement. Two questions are studied and answered in this paper: 1) is rigid registration sufficient in tracking the targets with an error smaller than the clinically significant size of prostate cancer and 2) what is the effect of the number of intraoperative slices on registration accuracy and speed? we propose multislice-to-volume registration algorithms for tracking the biopsy targets within the prostate. Three orthogonal plus additional transverse intraoperative slices are acquired in the approximate center of the prostate and registered with a high-resolution target planning volume. Both rigid and deformable scenarios were implemented. Both simulated and clinical MRI-guided robotic prostate biopsy data were used to assess tracking accuracy. average registration errors in clinical patient data were 2.6 mm for the rigid algorithm and 2.1 mm for the deformable algorithm. rigid tracking appears to be promising. Three tracking slices yield significantly high registration speed with an affordable error.

The sensitivity of motor response to needle nerve stimulation during ultrasound guided interscalene catheter placement.

PubMed

Fredrickson, Michael J

2008-01-01

Neurostimulation during single shot interscalene block has a significant false negative motor response rate. Compared with tangential needle approaches for single shot block, interscalene catheter (ISC) placement commonly involves Tuohy needles inserted longitudinally to the brachial plexus. This study aimed to determine the sensitivity of neurostimulation during ultrasound-guided ISC needle placement, and the feasibility of an ultrasound-guided ISC needle endpoint. One hundred fifty-five consecutive nonstimulating ISCs were placed with the needle tip position confirmed by the sonographic spread of 5 mL dextrose 5%. Catheter advancement was then blind 2 to 3 cm past the needle tip. A 0.8 mA electrical stimulus at 2 Hz was applied throughout. When a satisfactory image was obtained, neurostimulation was ignored and the minimum motor response amplitude noted. If imaging was equivocal, a brief appropriate motor response at 0.8 mA was sought. A sustained response at <0.5 mA was only sought if imaging was suboptimal. Prior to surgery conducted under general anesthesia, 30 mL ropivacaine 0.5% was administered through the ISC. Catheter success was defined as a recovery room numerical rating pain score of

Consistent evaluation of an ultrasound-guided surgical navigation system by utilizing an active validation platform

NASA Astrophysics Data System (ADS)

Kim, Younsu; Kim, Sungmin; Boctor, Emad M.

2017-03-01

An ultrasound image-guided needle tracking systems have been widely used due to their cost-effectiveness and nonionizing radiation properties. Various surgical navigation systems have been developed by utilizing state-of-the-art sensor technologies. However, ultrasound transmission beam thickness causes unfair initial evaluation conditions due to inconsistent placement of the target with respect to the ultrasound probe. This inconsistency also brings high uncertainty and results in large standard deviations for each measurement when we compare accuracy with and without the guidance. To resolve this problem, we designed a complete evaluation platform by utilizing our mid-plane detection and time of flight measurement systems. The evaluating system uses a PZT element target and an ultrasound transmitting needle. In this paper, we evaluated an optical tracker-based surgical ultrasound-guided navigation system whereby the optical tracker tracks marker frames attached on the ultrasound probe and the needle. We performed ten needle trials of guidance experiment with a mid-plane adjustment algorithm and with a B-mode segmentation method. With the midplane adjustment, the result showed a mean error of 1.62+/-0.72mm. The mean error increased to 3.58+/-2.07mm without the mid-plane adjustment. Our evaluation system can reduce the effect of the beam-thickness problem, and measure ultrasound image-guided technologies consistently with a minimal standard deviation. Using our novel evaluation system, ultrasound image-guided technologies can be compared under equal initial conditions. Therefore, the error can be evaluated more accurately, and the system provides better analysis on the error sources such as ultrasound beam thickness.

WE-AB-BRA-04: Evaluation of the Tumor Registration Error in Biopsy Procedures Performed Under Real Time PET/CT Guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanchon, L; INSERM U1101, Brest; Apte, A

2015-06-15

Purpose: PET/CT guidance is used for biopsies of metabolically active lesions, which are not well seen on CT alone or to target the metabolically active tissue in tumor ablations. It has also been shown that PET/CT guided biopsies provide an opportunity to verify the location of the lesion border at the place of needle insertion. However the error in needle placement with respect to the metabolically active region may be affected by motion between the PET/CT scan performed at the start of the procedure and the CT scan performed with the needle in place and this error has not beenmore » previously quantified. Methods: Specimens from 31 PET/CT guided biopsies were investigated and correlated to the intraoperative PET scan under an IRB approved HIPAA compliant protocol. For 4 of the cases in which larger motion was suspected a second PET scan was obtained with the needle in place. The CT and the PET images obtained before and after the needle insertion were used to calculate the displacement of the voxels along the needle path. CTpost was registered to CTpre using a free form deformable registration and then fused with PETpre. The shifts between the PET image contours (42% of SUVmax) for PETpre and PETpost were obtained at the needle position. Results: For these extreme cases the displacement of the CT voxels along the needle path ranged from 2.9 to 8 mm with a mean of 5 mm. The shift of the PET image segmentation contours (42% of SUVmax) at the needle position ranged from 2.3 to 7 mm between the two scans. Conclusion: Evaluation of the mis-registration between the CT with the needle in place and the pre-biopsy PET can be obtained using deformable registration of the respective CT scans and can be used to indicate the need of a second PET in real-time. This work is supported in part by a grant from Biospace Lab, S.A.« less

Follow-up of negative MRI-targeted prostate biopsies: when are we missing cancer?

PubMed

Gold, Samuel A; Hale, Graham R; Bloom, Jonathan B; Smith, Clayton P; Rayn, Kareem N; Valera, Vladimir; Wood, Bradford J; Choyke, Peter L; Turkbey, Baris; Pinto, Peter A

2018-05-21

Multiparametric magnetic resonance imaging (mpMRI) has improved clinicians' ability to detect clinically significant prostate cancer (csPCa). Combining or fusing these images with the real-time imaging of transrectal ultrasound (TRUS) allows urologists to better sample lesions with a targeted biopsy (Tbx) leading to the detection of greater rates of csPCa and decreased rates of low-risk PCa. In this review, we evaluate the technical aspects of the mpMRI-guided Tbx procedure to identify possible sources of error and provide clinical context to a negative Tbx. A literature search was conducted of possible reasons for false-negative TBx. This includes discussion on false-positive mpMRI findings, termed "PCa mimics," that may incorrectly suggest high likelihood of csPCa as well as errors during Tbx resulting in inexact image fusion or biopsy needle placement. Despite the strong negative predictive value associated with Tbx, concerns of missed disease often remain, especially with MR-visible lesions. This raises questions about what to do next after a negative Tbx result. Potential sources of error can arise from each step in the targeted biopsy process ranging from "PCa mimics" or technical errors during mpMRI acquisition to failure to properly register MRI and TRUS images on a fusion biopsy platform to technical or anatomic limits on needle placement accuracy. A better understanding of these potential pitfalls in the mpMRI-guided Tbx procedure will aid interpretation of a negative Tbx, identify areas for improving technical proficiency, and improve both physician understanding of negative Tbx and patient-management options.

Improved accuracy of ultrasound-guided therapies using electromagnetic tracking: in-vivo speed of sound measurements

NASA Astrophysics Data System (ADS)

Samboju, Vishal; Adams, Matthew; Salgaonkar, Vasant; Diederich, Chris J.; Cunha, J. Adam M.

2017-02-01

The speed of sound (SOS) for ultrasound devices used for imaging soft tissue is often calibrated to water, 1540 m/s1 , despite in-vivo soft tissue SOS varying from 1450 to 1613 m/s2 . Images acquired with 1540 m/s and used in conjunction with stereotactic external coordinate systems can thus result in displacement errors of several millimeters. Ultrasound imaging systems are routinely used to guide interventional thermal ablation and cryoablation devices, or radiation sources for brachytherapy3 . Brachytherapy uses small radioactive pellets, inserted interstitially with needles under ultrasound guidance, to eradicate cancerous tissue4 . Since the radiation dose diminishes with distance from the pellet as 1/r2 , imaging uncertainty of a few millimeters can result in significant erroneous dose delivery5,6. Likewise, modeling of power deposition and thermal dose accumulations from ablative sources are also prone to errors due to placement offsets from SOS errors7 . This work presents a method of mitigating needle placement error due to SOS variances without the need of ionizing radiation2,8. We demonstrate the effects of changes in dosimetry in a prostate brachytherapy environment due to patientspecific SOS variances and the ability to mitigate dose delivery uncertainty. Electromagnetic (EM) sensors embedded in the brachytherapy ultrasound system provide information regarding 3D position and orientation of the ultrasound array. Algorithms using data from these two modalities are used to correct bmode images to account for SOS errors. While ultrasound localization resulted in >3 mm displacements, EM resolution was verified to <1 mm precision using custom-built phantoms with various SOS, showing 1% accuracy in SOS measurement.

Dynamic soft tissue deformation estimation based on energy analysis

NASA Astrophysics Data System (ADS)

Gao, Dedong; Lei, Yong; Yao, Bin

2016-10-01

The needle placement accuracy of millimeters is required in many needle-based surgeries. The tissue deformation, especially that occurring on the surface of organ tissue, affects the needle-targeting accuracy of both manual and robotic needle insertions. It is necessary to understand the mechanism of tissue deformation during needle insertion into soft tissue. In this paper, soft tissue surface deformation is investigated on the basis of continuum mechanics, where a geometry model is presented to quantitatively approximate the volume of tissue deformation. The energy-based method is presented to the dynamic process of needle insertion into soft tissue based on continuum mechanics, and the volume of the cone is exploited to quantitatively approximate the deformation on the surface of soft tissue. The external work is converted into potential, kinetic, dissipated, and strain energies during the dynamic rigid needle-tissue interactive process. The needle insertion experimental setup, consisting of a linear actuator, force sensor, needle, tissue container, and a light, is constructed while an image-based method for measuring the depth and radius of the soft tissue surface deformations is introduced to obtain the experimental data. The relationship between the changed volume of tissue deformation and the insertion parameters is created based on the law of conservation of energy, with the volume of tissue deformation having been obtained using image-based measurements. The experiments are performed on phantom specimens, and an energy-based analytical fitted model is presented to estimate the volume of tissue deformation. The experimental results show that the energy-based analytical fitted model can predict the volume of soft tissue deformation, and the root mean squared errors of the fitting model and experimental data are 0.61 and 0.25 at the velocities 2.50 mm/s and 5.00 mm/s. The estimating parameters of the soft tissue surface deformations are proven to be useful for compensating the needle-targeting error in the rigid needle insertion procedure, especially for percutaneous needle insertion into organs.

Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morton, Daniel, E-mail: dmorton@bccancer.bc.ca; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia; Hilts, Michelle

Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomicmore » regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, small directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite observed seed displacements, acceptable postimplant dosimetry was achieved.« less

Validation of a technique for accurate fine-wire electrode placement into posterior gluteus medius using real-time ultrasound guidance.

PubMed

Hodges, P W; Kippers, V; Richardson, C A

1997-01-01

Fine-wire electromyography is primarily utilised for the recording of activity of the deep musculature, however, due to the location of these muscles, accurate electrode placement is difficult. Real-time ultrasound imaging (RTUI) of muscle tissue has been used for the guidance of the needle insertion for the placement of electrodes into the muscles of the abdominal wall. The validity of RTUI guidance of needle insertion into the deep muscles has not been determined. A cadaveric study was conducted to evaluate the accuracy with which RTUI can be used to guide fine-wire electrode placement using the posterior fibres of gluteus medius (PGM) as an example. Pilot studies revealed that the ultrasound resolution of cadaveric tissue is markedly reduced making it impossible to directly evaluate the technique, therefore, three studies were conducted. An initial study involved the demarcation of the anatomical boundaries of PGM using RTUI to define a technique based on an anatomical landmark that was consisent with the in vivo RTUI guided needle placement technique. This anatomical landmark was then used as the guide for the cadaveric needle insertion. Once the needle was positioned 0.05 ml of dye was introduced and the specimen dissected. The dye was accurately placed in PGM in 100% of the specimens. Finally, fine-wire electrodes were inserted into the PGM of five volunteers and manoeuvres performed indicating the accuracy of placement. This study supports the use of ultrasound imaging for the accurate guidance of needle insertion for fine-wire and needle EMG electrodes.

Cannula Versus Sharp Needle for Placement of Soft Tissue Fillers: An Observational Cadaver Study.

PubMed

van Loghem, Jani A J; Humzah, Dalvi; Kerscher, Martina

2017-12-13

Soft-tissue fillers have become important products for facial rejuvenation. Deep fat compartments and facial bones lose volume during the natural aging process. For the most natural-looking results, deep volumetric injections at strategic sites are therefore preferred. Supraperiosteal placement is performed with a sharp needle or a non-traumatic cannula. The primary objective was to determine whether there is a difference in precision between supraperiosteal placement with a sharp needle compared with a non-traumatic cannula in cadaver specimens. A secondary objective was to analyze the safety profiles of both injection techniques. Cadaver heads were injected with dye material and soft-tissue fillers at multiple aesthetic facial sites on the supraperiosteum and subsequently dissected for observation of dye and filler placement. The non-traumatic cannula technique resulted in product being confined to the deep anatomic layers. In contrast, with the sharp needle technique, material was placed in multiple anatomic layers, from the periosteum to more superficial skin layers. For both techniques results were consistent for all facial sites. Although direct extrapolation from cadavers to the in vivo situation cannot be made, cannulae showed more precision in placement of product. With the sharp needle, the material was injected on the periosteum, and then migrated in a retrograde direction along the trajectory of the needle path, ending up in multiple anatomic layers. The sharp needle technique also showed a higher complication risk with intra-arterial injection occurring, even though the needle tip was positioned on the periosteum and the product was injected with the needle in constant contact with the periosteum. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com

EM-navigated catheter placement for gynecologic brachytherapy: an accuracy study

NASA Astrophysics Data System (ADS)

Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

2014-03-01

Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and /or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems.

Evaluation of lumbar transforaminal epidural injections with needle placement and contrast flow patterns: a prospective, descriptive report.

PubMed

Manchikanti, Laxmaiah; Cash, Kim A; Pampati, Vidyasagar; Damron, Kim S; McManus, Carla D

2004-04-01

Transforaminal epidural steroid injection is one of the commonly employed modalities of treatment in managing nerve root pain. However, there have been no controlled prospective evaluations of epidural and nerve root contrast distribution patterns and other aspects of fluoroscopically directed lumbosacral transforaminal epidural steroid injections. To evaluate contrast flow patterns and intravascular needle placement of fluoroscopically guided lumbosacral transforaminal epidural injections. A prospective, observational study. A total of 100 consecutive patients undergoing fluoroscopically guided transforaminal epidural steroid injections were evaluated. The contrast flow patterns, ventral or dorsal epidural filling, nerve root filling, C-arm time, and intravascular needle placement were evaluated. Ventral epidural filling was seen in 88% of the procedures, in contrast to dorsal filling noted in 9% of the procedures. Nerve root filling was seen in 97% of the procedures. Total intravenous placement of the needle was noted in 22% of the procedures, whereas negative flashback and aspiration was noted in 5% of the procedures. Lumbosacral transforaminal epidural injections, performed under fluoroscopic visualization, provide excellent nerve root filling and ventral epidural filling patterns. However, unrecognized intravascular needle placement with negative flashback or aspiration was noted in 5% of the procedures.

Does a paresthesia during spinal needle insertion indicate intrathecal needle placement?

PubMed

Pong, Ryan P; Gmelch, Benjamin S; Bernards, Christopher M

2009-01-01

Paresthesias are relatively common during spinal needle insertion, however, the clinical significance of the paresthesia is unknown. A paresthesia may result from needle-to-nerve contact with a spinal nerve in the epidural space, or, with far lateral needle placement, may result from contact with a spinal nerve within the intervertebral foramen. However, it is also possible and perhaps more likely, that paresthesias occur when the spinal needle contacts a spinal nerve root within the subarachnoid space. This study was designed to test this latter hypothesis. Patients (n = 104) scheduled for surgery under spinal anesthesia were observed during spinal needle insertion. If a paresthesia occurred, the needle was fixed in place and the stylet removed to observe whether cerebrospinal fluid (CSF) flowed from the hub. The presence of CSF was considered proof that the needle had entered the subarachnoid space. Paresthesias occurred in 14/103 (13.6%) of patients; 1 patient experienced a paresthesia twice. All paresthesias were transient. Following a paresthesia, CSF was observed in the needle hub 86.7% (13/15) of the time. Our data suggest that the majority of transient paresthesias occur when the spinal needle enters the subarachnoid space and contacts a spinal nerve root. Therefore, when transient paresthesias occur during spinal needle placement it is appropriate to stop and assess for the presence of CSF in the needle hub, rather than withdraw and redirect the spinal needle away from the side of the paresthesia as some authors have suggested.

Psycho-Motor and Error Enabled Simulations: Modeling Vulnerable Skills in the Pre-Mastery Phase

DTIC Science & Technology

2016-04-01

participants. Multiple abstracts and posters were created for surgical conferences attended. These works concentrated on data from pre and post ...analyzed to give every participant a perspective of the smallest difference in stiffness they could differentiate. Based on the results the tests were...camera was affixed to a post mounted to this station’s table to capture a close-up view of the participant’s placement of needles on the simulation

Toward a 3D transrectal ultrasound system for verification of needle placement during high-dose-rate interstitial gynecologic brachytherapy.

PubMed

Rodgers, Jessica Robin; Surry, Kathleen; Leung, Eric; D'Souza, David; Fenster, Aaron

2017-05-01

Treatment for gynecologic cancers, such as cervical, recurrent endometrial, and vaginal malignancies, commonly includes external-beam radiation and brachytherapy. In high-dose-rate (HDR) interstitial gynecologic brachytherapy, radiation treatment is delivered via hollow needles that are typically inserted through a template on the perineum with a cylinder placed in the vagina for stability. Despite the need for precise needle placement to minimize complications and provide optimal treatment, there is no standard intra-operative image-guidance for this procedure. While some image-guidance techniques have been proposed, including magnetic resonance (MR) imaging, X-ray computed tomography (CT), and two-dimensional (2D) transrectal ultrasound (TRUS), these techniques have not been widely adopted. In order to provide intra-operative needle visualization and localization during interstitial brachytherapy, we have developed a three-dimensional (3D) TRUS system. This study describes the 3D TRUS system and reports on the system validation and results from a proof-of-concept patient study. To obtain a 3D TRUS image, the system rotates a conventional 2D endocavity transducer through 170 degrees in 12 s, reconstructing the 2D frames into a 3D image in real-time. The geometry of the reconstruction was validated using two geometric phantoms to ensure the accuracy of the linear measurements in each of the image coordinate directions and the volumetric accuracy of the system. An agar phantom including vaginal and rectal canals, as well as a model uterus and tumor, was designed and used to test the visualization and localization of the interstitial needles under idealized conditions by comparing the needles' positions between the 3D TRUS scan and a registered MR image. Five patients undergoing HDR interstitial gynecologic brachytherapy were imaged using the 3D TRUS system following the insertion of all needles. This image was manually, rigidly registered to the clinical postinsertion CT scan based on the vaginal cylinder of the needle template. The positions of the tips and the trajectory of the needle paths were compared between the modalities. The observed geometric errors of the system were ≤ 0.3 mm in each of the three coordinate planes of the 3D US image and the mean measured volumetric error was 0.10 cm 3 . In the phantom study, the mean needle tip difference was 1.54 ± 0.71 mm and the mean trajectory difference was 0.94 ± 0.89 degrees (n = 14). In the in vivo study, a total of 73 needles were placed, of which 88% of needles were visible and 79% of tips were identifiable in the 3D TRUS images. Six of the nine needles that were not visible were due to shadowing artifacts created by the presence of the vaginal cylinder of the needle template. The mean distance between corresponding needle tips in the two modalities was 3.82 ± 1.86 mm and the mean trajectory difference was 3.04 ± 1.63 degrees for the five patients. In this proof-of-concept study, the 3D TRUS system allowed for localization of needles not obscured by shadowing artifacts, providing a method for visualizing needles intra-operatively during HDR interstitial brachytherapy of gynecologic cancers and providing the potential for 3D image-guidance. © 2017 American Association of Physicists in Medicine.

Placement of empty catheters for an HDR-emulating LDR prostate brachytherapy technique: comparison to standard intraoperative planning.

PubMed

Niedermayr, Thomas R; Nguyen, Paul L; Murciano-Goroff, Yonina R; Kovtun, Konstantin A; Neubauer Sugar, Emily; Cail, Daniel W; O'Farrell, Desmond A; Hansen, Jorgen L; Cormack, Robert A; Buzurovic, Ivan; Wolfsberger, Luciant T; O'Leary, Michael P; Steele, Graeme S; Devlin, Philip M; Orio, Peter F

2014-01-01

We sought to determine whether placing empty catheters within the prostate and then inverse planning iodine-125 seed locations within those catheters (High Dose Rate-Emulating Low Dose Rate Prostate Brachytherapy [HELP] technique) would improve concordance between planned and achieved dosimetry compared with a standard intraoperative technique. We examined 30 consecutive low dose rate prostate cases performed by standard intraoperative technique of planning followed by needle placement/seed deposition and compared them to 30 consecutive low dose rate prostate cases performed by the HELP technique. The primary endpoint was concordance between planned percentage of the clinical target volume that receives at least 100% of the prescribed dose/dose that covers 90% of the volume of the clinical target volume (V100/D90) and the actual V100/D90 achieved at Postoperative Day 1. The HELP technique had superior concordance between the planned target dosimetry and what was actually achieved at Day 1 and Day 30. Specifically, target D90 at Day 1 was on average 33.7 Gy less than planned for the standard intraoperative technique but was only 10.5 Gy less than planned for the HELP technique (p < 0.001). Day 30 values were 16.6 Gy less vs. 2.2 Gy more than planned, respectively (p = 0.028). Day 1 target V100 was 6.3% less than planned with standard vs. 2.8% less for HELP (p < 0.001). There was no significant difference between the urethral and rectal concordance (all p > 0.05). Placing empty needles first and optimizing the plan to the known positions of the needles resulted in improved concordance between the planned and the achieved dosimetry to the target, possibly because of elimination of errors in needle placement. Copyright © 2014 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Virtobot 2.0: the future of automated surface documentation and CT-guided needle placement in forensic medicine.

PubMed

Ebert, Lars Christian; Ptacek, Wolfgang; Breitbeck, Robert; Fürst, Martin; Kronreif, Gernot; Martinez, Rosa Maria; Thali, Michael; Flach, Patricia M

2014-06-01

In this paper we present the second prototype of a robotic system to be used in forensic medicine. The system is capable of performing automated surface documentation using photogrammetry, optical surface scanning and image-guided, post-mortem needle placement for tissue sampling, liquid sampling, or the placement of guide wires. The upgraded system includes workflow optimizations, an automatic tool-change mechanism, a new software module for trajectory planning and a fully automatic computed tomography-data-set registration algorithm. We tested the placement accuracy of the system by using a needle phantom with radiopaque markers as targets. The system is routinely used for surface documentation and resulted in 24 surface documentations over the course of 11 months. We performed accuracy tests for needle placement using a biopsy phantom, and the Virtobot placed introducer needles with an accuracy of 1.4 mm (±0.9 mm). The second prototype of the Virtobot system is an upgrade of the first prototype but mainly focuses on streamlining the workflow and increasing the level of automation and also has an easier user interface. These upgrades make the Virtobot a potentially valuable tool for case documentation in a scalpel-free setting that uses purely imaging techniques and minimally invasive procedures and is the next step toward the future of virtual autopsy.

Development of an MRI-Guided Intra-Prostatic Needle Placement System

DTIC Science & Technology

2011-07-01

and intra-operative imaging using techniques such as those described by Haker , et al. [18]. Target points for the needle insertion are selected... Haker , S., Fichtinger, G., Tem- pany, C.: Transperineal prostate biopsy under magnetic resonance image guid- ance: A needle placement accuracy study 26...clinically localized prostate cancer. Int J Radiat Oncol Biol Phys 42(3), 507–515 (1998) 9. DiMaio, S.P., Pieper, S., Chinzei, K., Hata, N., Haker , S.J

Robotic Needle Guide for Prostate Brachytherapy: Clinical Testing of Feasibility and Performance

PubMed Central

Song, Danny Y; Burdette, Everette C; Fiene, Jonathan; Armour, Elwood; Kronreif, Gernot; Deguet, Anton; Zhang, Zhe; Iordachita, Iulian; Fichtinger, Gabor; Kazanzides, Peter

2010-01-01

Purpose Optimization of prostate brachytherapy is constrained by tissue deflection of needles and fixed spacing of template holes. We developed and clinically tested a robotic guide towards the goal of allowing greater freedom of needle placement. Methods and Materials The robot consists of a small tubular needle guide attached to a robotically controlled arm. The apparatus is mounted and calibrated to operate in the same coordinate frame as a standard template. Translation in x and y directions over the perineum ±40mm are possible. Needle insertion is performed manually. Results Five patients were treated in an IRB-approved study. Confirmatory measurements of robotic movements for initial 3 patients using infrared tracking showed mean error of 0.489 mm (SD 0.328 mm). Fine adjustments in needle positioning were possible when tissue deflection was encountered; adjustments were performed in 54/179 (30.2%) needles placed, with 36/179 (20.1%) adjustments of > 2mm. Twenty-seven insertions were intentionally altered to positions between the standard template grid to improve the dosimetric plan or avoid structures such as pubic bone and blood vessels. Conclusions Robotic needle positioning provided a means of compensating for needle deflections as well as the ability to intentionally place needles into areas between the standard template holes. To our knowledge, these results represent the first clinical testing of such a system. Future work will be incorporation of direct control of the robot by the physician, adding software algorithms to help avoid robot collisions with the ultrasound, and testing the angulation capability in the clinical setting. PMID:20729152

Finite element analyses of a dual actuated prototype of a smart needle

NASA Astrophysics Data System (ADS)

Konh, Bardia; Podder, Tarun K.

2017-04-01

Brachytherapy is one of the most effective modalities for treating early stage prostate cancer. In this procedure, radioactive seeds are being placed in the prostate to kill the tumorous cells. Inaccurate placement of seeds can underdose the tumor and dangerously overdose the critical structures (urethra, rectum, bladder) and adjacent healthy tissues. It is very difficult, if not impossible, for the surgeons to compensate the needle misplacement errors while using the conventional passive straight needles. The smart needles actuated by shape memory alloy (SMA) wires are being developed to provide more actuation and control for the surgeons to achieve more geometric conformity. In our recent work, a prototype of a smart needle was developed where not only the actuation of SMA wires were incorporated, but also shape memory polymers (SMPs) were included in the design introducing a soft joint element to further assist the flexibility of the active surgical needles. The additional actuation of shape memory polymers provided the capability of reaching much high flexibility that was not achievable before. However, there are some disadvantages using this active SMP component compared to a passive Nylon joint component that are discussed in this work. The utilization of a heated SMP as a soft joint showed about 20% improvement in the final needle tip deflection. This work presents the finite element studies of the developed prototype. A finite element model that could accurately predict the behavior of the smart needle could be very valuable in analyzing and optimizing the future novel designs.

Botulinum toxin type A injection into the gastrocnemius muscle for spastic equinus in adults with stroke: a randomized controlled trial comparing manual needle placement, electrical stimulation and ultrasonography-guided injection techniques.

PubMed

Picelli, Alessandro; Tamburin, Stefano; Bonetti, Paola; Fontana, Carla; Barausse, Martina; Dambruoso, Francesca; Gajofatto, Francesca; Santilli, Valter; Smania, Nicola

2012-11-01

The aim of this study was to compare the clinical outcomes of manual needle placement, electrical stimulation, and ultrasonography-guided techniques for botulinum toxin injection into the gastrocnemius of adults with spastic equinus after stroke. After randomization into three groups, each patient received the same dose of botulinum toxin type A into the lateral and medial head of the gastrocnemius muscle (OnabotulinumtoxinA, 100U per head) of the affected leg. The manual needle placement group (n = 15) underwent injections using anatomic landmarks and palpation; the electrical stimulation group (n = 15) received injections with electrical stimulation guidance; and the ultrasonography group (n = 17) was injected under sonographic guidance. The modified Ashworth scale, the Tardieu scale, and the ankle passive range of motion were measured at baseline and 1 mo after injection. Nonparametric statistical analysis was used. One month after injection, the modified Ashworth scale improved better in the ultrasonography group than in the manual needle placement group (P = 0.008). The ankle passive range of motion improved better in the ultrasonography group than in the electrical stimulation (P = 0.004) and manual needle placement (P < 0.001) groups. No difference was found between groups for the Tardieu scale. Ultrasonography-guided injection technique could improve the clinical outcome of botulinum toxin injections into the gastrocnemius of adults with spastic equinus.

Experimental analysis of robot-assisted needle insertion into porcine liver.

PubMed

Wang, Wendong; Shi, Yikai; Goldenberg, Andrew A; Yuan, Xiaoqing; Zhang, Peng; He, Lijing; Zou, Yingjie

2015-01-01

How to improve placement accuracy of needle insertion into liver tissue is of paramount interest to physicians. A robot-assisted system was developed to experimentally demonstrate its advantages in needle insertion surgeries. Experiments of needle insertion into porcine liver tissue were performed with conic tip needle (diameter 8 mm) and bevel tip needle (diameter 1.5 mm) in this study. Manual operation was designed to compare the performance of the presented robot-assisted system. The real-time force curves show outstanding advantages of robot-assisted operation in improving the controllability and stability of needle insertion process by comparing manual operation. The statistics of maximum force and average force further demonstrates robot-assisted operation causes less oscillation. The difference of liver deformation created by manual operation and robot-assisted operation is very low, 1 mm for average deformation and 2 mm for maximum deformation. To conclude, the presented robot-assisted system can improve placement accuracy of needle by stably control insertion process.

Ultrasound-guided thermocouple placement for cryosurgery.

PubMed

Abramovits, W; Pruiksma, R; Bose, S

1996-09-01

Although cryosurgical methods have high cure rates, imprecise estimates of both skin lesion depth and destructive temperature front location result in subjective technique in skin malignancy treatments. We evaluated the possibility of newer ultrasound equipment to assist in the precise placement of thermocouples in human skin. DermaScan C ver. 3 ultrasonographic equipment fitted with a sharp focus probe with a frequency of 20 MHz and a scan length of 12.1 mm was used to locate thermocouples with 27- and 30-gauge needles. We successfully and reproducibly located thermocouples and thin needles, and accurately measured their distance from the skin surface. Ultrasound is a useful method for the accurate placement of thermocouples, and needles as thin as 30 gauge for monitoring in cryosurgery.

The anterior approach for a non-image-guided intra-articular hip injection.

PubMed

Mei-Dan, Omer; McConkey, Mark O; Petersen, Brian; McCarty, Eric; Moreira, Brett; Young, David A

2013-06-01

The purpose of this study was to investigate and validate the accuracy and safety of a technique using an anterior approach for non-image-guided intra-articular injection of the hip by use of anatomic landmarks. We enrolled 55 patients. Injections were performed before supine hip arthroscopy after landmarking and before application of traction. After the needle insertion, success was confirmed with an air arthrogram and by direct visualization after arthroscope insertion. Accuracy and difficulty achieving correct needle placement were correlated with age, weight, height, body mass index, body type, gender, and surgical indication, as well as femoral and pelvic morphology. Forty-five patients who underwent injection in the office were followed up separately to document injection side effects. Needle placement accuracy was correlated to patients' demographics. All statistical tests with P values were 2 sided, with the level of significance set at P < .05. There were 51 correct needle placements and 4 misses, yielding a 93% success rate. The most common location for needle placement was the upper medial head-neck junction. Female gender was correlated with a more difficult needle placement and misses in relation to group size (P = .06). The reasons for misplacements of the needle were a high-riding trochanter, increased femoral version, thick adipose tissue over the landmarks, and variant of ilium morphology. Of 45 patients in the side effect study arm, 3 reported sensory changes of the lateral femoral cutaneous nerve that resolved within 24 hours. Hip injections by use of the direct anterior approach, from the intersection of the lines drawn from the anterior superior iliac spine and 1 cm distal to the tip of the greater trochanter, are safe and reproducible. Patient characteristics, such as increased subcutaneous adipose tissue or osseous anatomic variants, can lead to difficulty in placing the needle successfully. These characteristics can be predicted with the aid of physical examination and careful study of the pelvic radiographs. Level IV, therapeutic case series. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Efficacy of the EZ-IO needle driver for out-of-hospital intraosseous access--a preliminary, observational, multicenter study.

PubMed

Schalk, Richard; Schweigkofler, Uwe; Lotz, Gösta; Zacharowski, Kai; Latasch, Leo; Byhahn, Christian

2011-10-26

Intraosseous (IO) access represents a reliable alternative to intravenous vascular access and is explicitly recommended in the current guidelines of the European Resuscitation Council when intravenous access is difficult or impossible. We therefore aimed to study the efficacy of the intraosseous needle driver EZ-IO in the prehospital setting. During a 24-month period, all cases of prehospital IO access using the EZ-IO needle driver within three operational areas of emergency medical services were prospectively recorded by a standardized questionnaire that needed to be filled out by the rescuer immediately after the mission and sent to the primary investigator. We determined the rate of successful insertion of the IO needle, the time required, immediate procedure-related complications, the level of previous experience with IO access, and operator's subjective satisfaction with the device. 77 IO needle insertions were performed in 69 adults and five infants and children by emergency physicians (n = 72 applications) and paramedics (n = 5 applications). Needle placement was successful at the first attempt in all but 2 adults (one patient with unrecognized total knee arthroplasty, one case of needle obstruction after placement). The majority of users (92%) were relative novices with less than five previous IO needle placements. Of 22 responsive patients, 18 reported pain upon fluid administration via the needle. The rescuers' subjective rating regarding handling of the device and ease of needle insertion, as described by means of an analogue scale (0 = entirely unsatisfied, 10 = most satisfied), provided a median score of 10 (range 1-10). The EZ-IO needle driver was an efficient alternative to establish immediate out-of-hospital vascular access. However, significant pain upon intramedullary infusion was observed in the majority of responsive patients.

Optimal training for emergency needle thoracostomy placement by prehospital personnel: didactic teaching versus a cadaver-based training program.

PubMed

Grabo, Daniel; Inaba, Kenji; Hammer, Peter; Karamanos, Efstathios; Skiada, Dimitra; Martin, Matthew; Sullivan, Maura; Demetriades, Demetrios

2014-09-01

Tension pneumothorax can rapidly progress to cardiac arrest and death if not promptly recognized and appropriately treated. We sought to evaluate the effectiveness of traditional didactic slide-based lectures (SBLs) as compared with fresh tissue cadaver-based training (CBT) for placement of needle thoracostomy (NT). Forty randomly selected US Navy corpsmen were recruited to participate from incoming classes of the Navy Trauma Training Center at the LAC + USC Medical Center and were then randomized to one of two NT teaching methods. The following outcomes were compared between the two study arms: (1) time required to perform the procedure, (2) correct placement of the needle, and (3) magnitude of deviation from the correct position. During the study period, a total of 40 corpsmen were enrolled, 20 randomized to SBL and 20 to CBT arms. When outcomes were analyzed, time required to NT placement was not different between the two arms. Examination of the location of needle placement revealed marked differences between the two study groups. Only a minority of the SBL group (35%) placed the NT correctly in the second intercostal space. In comparison, the majority of corpsmen assigned to the CBT group demonstrated accurate placement in the second intercostal space (75%). In a CBT module, US Navy corpsmen were better trained to place NT accurately than their traditional didactic SBL counterparts. Further studies are indicated to identify the optimal components of effective simulation training for NT and other emergent interventions.

Accuracy of electromyography needle placement in cadavers: non-guided vs. ultrasound guided.

PubMed

Boon, Andrea J; Oney-Marlow, Theresa M; Murthy, Naveen S; Harper, Charles M; McNamara, Terrence R; Smith, Jay

2011-07-01

Accuracy of needle electromyography is typically ensured by use of anatomical landmarks and auditory feedback related to voluntary activation of the targeted muscle; however, in certain clinical situations, landmarks may not be palpable, auditory feedback may be limited or not present, and targeting a specific muscle may be more critical. In such settings, image guidance might significantly enhance accuracy. Two electromyographers with different levels of experience examined 14 muscles in each of 4 fresh-frozen cadaver lower limbs. Each muscle was tested a total of eight times; four fine wires were inserted without ultrasound (US) guidance and four were inserted under US guidance. Overall accuracy as well as accuracy rates for the individual electromyographers were calculated. Non-guided needle placement was significantly less accurate than US-guided needle placement, particularly in the hands of less experienced electromyographers, supporting the use of real-time US guidance in certain challenging situations in the electromyography laboratory. Copyright © 2011 Wiley Periodicals, Inc.

A serious game for learning ultrasound-guided needle placement skills.

PubMed

Chan, Wing-Yin; Qin, Jing; Chui, Yim-Pan; Heng, Pheng-Ann

2012-11-01

Ultrasound-guided needle placement is a key step in a lot of radiological intervention procedures such as biopsy, local anesthesia and fluid drainage. To help training future intervention radiologists, we develop a serious game to teach the skills involved. We introduce novel techniques for realistic simulation and integrate game elements for active and effective learning. This game is designed in the context of needle placement training based on the some essential characteristics of serious games. Training scenarios are interactively generated via a block-based construction scheme. A novel example-based texture synthesis technique is proposed to simulate corresponding ultrasound images. Game levels are defined based on the difficulties of the generated scenarios. Interactive recommendation of desirable insertion paths is provided during the training as an adaptation mechanism. We also develop a fast physics-based approach to reproduce the shadowing effect of needles in ultrasound images. Game elements such as time-attack tasks, hints and performance evaluation tools are also integrated in our system. Extensive experiments are performed to validate its feasibility for training.

A pulsatile pressure waveform is a sensitive marker for confirming the location of the thoracic epidural space.

PubMed

Lennox, Pamela H; Umedaly, Hamed S; Grant, Raymer P; White, S Adrian; Fitzmaurice, Brett G; Evans, Kenneth G

2006-10-01

The purpose of this study was to assess the validity of using a pulsatile, pressure waveform transduced from the epidural space through an epidural needle or catheter to confirm correct placement for maximal analgesia and to compare 3 different types of catheters' ability to transduce a waveform. A single-center, prospective, randomized trial. A tertiary-referral hospital. Eighty-one patients undergoing posterolateral thoracotomy who required a thoracic epidural catheter for postoperative pain management. Each epidural needle and each epidural catheter was transduced to determine if there was a pulsatile waveform exhibited. Sensitivity of the pulsatile waveform transduced through an epidural needle to identify correct placement of the epidural needle and the sensitivity of each catheter type to identify placement were compared. In 79 of 81 cases (97.5%), the waveform transduced directly through the epidural needle had a pulsatile characteristic as determined by blinded observers. In a total of 53 of 81 epidural catheters (65.4%), the transduced waveform displayed pulsations. Twenty-four of 27 catheters in group S-P/Sims Portex (Smiths Medical MD, Inc, St Paul, MN) (88.9%) transduced a pulsatile tracing from the epidural space, a significantly greater percentage than in the other 2 groups (p = 0.02). The technique of transducing the pressure waveform from the epidural needle inserted in the epidural space is a sensitive and reliable alternative to other techniques for confirmation of correct epidural catheter placement. The technique is simple, sensitive, and inexpensive and uses equipment available in any operating room.

Automatic planning of needle placement for robot-assisted percutaneous procedures.

PubMed

Belbachir, Esia; Golkar, Ehsan; Bayle, Bernard; Essert, Caroline

2018-04-18

Percutaneous procedures allow interventional radiologists to perform diagnoses or treatments guided by an imaging device, typically a computed tomography (CT) scanner with a high spatial resolution. To reduce exposure to radiations and improve accuracy, robotic assistance to needle insertion is considered in the case of X-ray guided procedures. We introduce a planning algorithm that computes a needle placement compatible with both the patient's anatomy and the accessibility of the robot within the scanner gantry. Our preoperative planning approach is based on inverse kinematics, fast collision detection, and bidirectional rapidly exploring random trees coupled with an efficient strategy of node addition. The algorithm computes the allowed needle entry zones over the patient's skin (accessibility map) from 3D models of the patient's anatomy, the environment (CT, bed), and the robot. The result includes the admissible robot joint path to target the prescribed internal point, through the entry point. A retrospective study was performed on 16 patients datasets in different conditions: without robot (WR) and with the robot on the left or the right side of the bed (RL/RR). We provide an accessibility map ensuring a collision-free path of the robot and allowing for a needle placement compatible with the patient's anatomy. The result is obtained in an average time of about 1 min, even in difficult cases. The accessibility maps of RL and RR covered about a half of the surface of WR map in average, which offers a variety of options to insert the needle with the robot. We also measured the average distance between the needle and major obstacles such as the vessels and found that RL and RR produced needle placements almost as safe as WR. The introduced planning method helped us prove that it is possible to use such a "general purpose" redundant manipulator equipped with a dedicated tool to perform percutaneous interventions in cluttered spaces like a CT gantry.

Design of a Teleoperated Needle Steering System for MRI-guided Prostate Interventions

PubMed Central

Seifabadi, Reza; Iordachita, Iulian; Fichtinger, Gabor

2013-01-01

Accurate needle placement plays a key role in success of prostate biopsy and brachytherapy. During percutaneous interventions, the prostate gland rotates and deforms which may cause significant target displacement. In these cases straight needle trajectory is not sufficient for precise targeting. Although needle spinning and fast insertion may be helpful, they do not entirely resolve the issue. We propose robot-assisted bevel-tip needle steering under MRI guidance as a potential solution to compensate for the target displacement. MRI is chosen for its superior soft tissue contrast in prostate imaging. Due to the confined workspace of the MRI scanner and the requirement for the clinician to be present inside the MRI room during the procedure, we designed a MRI-compatible 2-DOF haptic device to command the needle steering slave robot which operates inside the scanner. The needle steering slave robot was designed to be integrated with a previously developed pneumatically actuated transperineal robot for MRI-guided prostate needle placement. We describe design challenges and present the conceptual design of the master and slave robots and the associated controller. PMID:24649480

A Fabry-Perot Interferometry Based MRI-Compatible Miniature Uniaxial Force Sensor for Percutaneous Needle Placement

PubMed Central

Shang, Weijian; Su, Hao; Li, Gang; Furlong, Cosme; Fischer, Gregory S.

2014-01-01

Robot-assisted surgical procedures, taking advantage of the high soft tissue contrast and real-time imaging of magnetic resonance imaging (MRI), are developing rapidly. However, it is crucial to maintain tactile force feedback in MRI-guided needle-based procedures. This paper presents a Fabry-Perot interference (FPI) based system of an MRI-compatible fiber optic sensor which has been integrated into a piezoelectrically actuated robot for prostate cancer biopsy and brachytherapy in 3T MRI scanner. The opto-electronic sensing system design was minimized to fit inside an MRI-compatible robot controller enclosure. A flexure mechanism was designed that integrates the FPI sensor fiber for measuring needle insertion force, and finite element analysis was performed for optimizing the correct force-deformation relationship. The compact, low-cost FPI sensing system was integrated into the robot and calibration was conducted. The root mean square (RMS) error of the calibration among the range of 0–10 Newton was 0.318 Newton comparing to the theoretical model which has been proven sufficient for robot control and teleoperation. PMID:25126153

Raman Spectroscopy Differentiates Each Tissue From the Skin to the Spinal Cord: A Novel Method for Epidural Needle Placement?

PubMed Central

Anderson, T. Anthony; Kang, Jeon Woong; Gubin, Tatyana; Dasari, Ramachandra R.; So, Peter T. C.

2016-01-01

BACKGROUND Neuraxial anesthesia and epidural steroid injection techniques require precise anatomical targeting to ensure successful and safe analgesia. Previous studies suggest that only some of the tissues encountered during these procedures can be identified by spectroscopic methods, and no previous study has investigated the use of Raman, diffuse reflectance, and fluorescence spectroscopies. The authors hypothesized that real-time needle-tip spectroscopy may aid epidural needle placement and tested the ability of spectroscopy to distinguish each of the tissues in the path of neuraxial needles. METHODS For comparison of detection methods, the spectra of individual, dissected ex vivo paravertebral and neuraxial porcine tissues were collected using Raman spectroscopy (RS), diffuse reflectance spectroscopy (DRS), and fluorescence spectroscopy (FS). Real-time spectral guidance was tested using a 2 mm inner diameter fiber optic probe-in-needle device. Raman spectra were collected during the needle’s passage through intact paravertebral and neuraxial porcine tissue and analyzed afterward. The RS tissue signatures were verified as mapping to individual tissue layers using histochemical staining and widefield microscopy. RESULTS Raman spectroscopy revealed a unique spectrum for all ex vivo paravertebral and neuraxial tissue layers; DRS and FS spectra were not distinct for all tissues. Moreover, when accounting for the expected order of tissues, real-time Raman spectra recorded during needle insertion also permitted identification of each paravertebral and neuraxial porcine tissue. CONCLUSIONS This study demonstrates Raman spectroscopy can distinguish the tissues encountered during epidural needle insertion. This technology may prove useful during needle placement by providing evidence of its anatomical localization. PMID:27466032

In-Bore Prostate Transperineal Interventions with an MRI-guided Parallel Manipulator: System Development and Preliminary Evaluation

PubMed Central

Eslami, Sohrab; Shang, Weijian; Li, Gang; Patel, Nirav; Fischer, Gregory S.; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M.; Iordachita, Iulian

2015-01-01

Background The robot-assisted minimally-invasive surgery is well recognized as a feasible solution for diagnosis and treatment of the prostate cancer in human. Methods In this paper the kinematics of a parallel 4 Degrees-of-Freedom (DOF) surgical manipulator designed for minimally invasive in-bore prostate percutaneous interventions through the patient's perineum. The proposed manipulator takes advantage of 4 sliders actuated by MRI-compatible piezoelectric motors and incremental rotary encoders. Errors, mostly originating from the design and manufacturing process, need to be identified and reduced before the robot is deployed in the clinical trials. Results The manipulator has undergone several experiments to evaluate the repeatability and accuracy of the needle placement which is an essential concern in percutaneous prostate interventions. Conclusion The acquired results endorse the sustainability, precision (about 1 mm in air (in x or y direction) at the needle's reference point) and reliability of the manipulator. PMID:26111458

3T MR-guided in-bore transperineal prostate biopsy: A comparison of robotic and manual needle-guidance templates.

PubMed

Tilak, Gaurie; Tuncali, Kemal; Song, Sang-Eun; Tokuda, Junichi; Olubiyi, Olutayo; Fennessy, Fiona; Fedorov, Andriy; Penzkofer, Tobias; Tempany, Clare; Hata, Nobuhiko

2015-07-01

To demonstrate the utility of a robotic needle-guidance template device as compared to a manual template for in-bore 3T transperineal magnetic resonance imaging (MRI)-guided prostate biopsy. This two-arm mixed retrospective-prospective study included 99 cases of targeted transperineal prostate biopsies. The biopsy needles were aimed at suspicious foci noted on multiparametric 3T MRI using manual template (historical control) as compared with a robotic template. The following data were obtained: the accuracy of average and closest needle placement to the focus, histologic yield, percentage of cancer volume in positive core samples, complication rate, and time to complete the procedure. In all, 56 cases were performed using the manual template and 43 cases were performed using the robotic template. The mean accuracy of the best needle placement attempt was higher in the robotic group (2.39 mm) than the manual group (3.71 mm, P < 0.027). The mean core procedure time was shorter in the robotic (90.82 min) than the manual group (100.63 min, P < 0.030). Percentage of cancer volume in positive core samples was higher in the robotic group (P < 0.001). Cancer yields and complication rates were not statistically different between the two subgroups (P = 0.557 and P = 0.172, respectively). The robotic needle-guidance template helps accurate placement of biopsy needles in MRI-guided core biopsy of prostate cancer. © 2014 Wiley Periodicals, Inc.

Novel needle guide reduces time to perform ultrasound-guided femoral nerve catheter placement: A randomised controlled trial.

PubMed

Turan, Alparslan; Babazade, Rovnat; Elsharkawy, Hesham; Esa, Wael Ali Sakr; Maheshwari, Kamal; Farag, Ehab; Zimmerman, Nicole M; Soliman, Loran Mounir; Sessler, Daniel I

2017-03-01

Ultrasound-guided nerve blocks have become the standard when performing regional nerve blocks in anaesthesia. Infiniti Plus (CIVCO Medical Solutions, Kalona, Iowa, USA) is a needle guide that has been recently developed to help clinicians in performing ultrasound-guided nerve blocks. We tested the hypothesis that femoral nerve catheter placement carried out with the Infiniti Plus needle guide will be quicker to perform than without the Infiniti Plus. Secondary aims were to assess whether the Infiniti Plus needle guide decreased the number of block attempts and also whether it improved needle visibility. A randomised, controlled trial. Cleveland Clinic, Cleveland, Ohio, USA. We enrolled adult patients having elective total knee arthroplasty with a femoral nerve block and femoral nerve catheter. Patients, who were pregnant or those who had preexisting neuropathy involving the surgical limb, coagulopathy, infection at the block site or allergy to local anaesthetics were excluded. Patients were randomised into two groups to receive the ultrasound-guided femoral nerve catheter placement with or without the Infiniti Plus needle guide. The time taken to place the femoral nerve catheter, the number of attempts, the success rate and needle visibility were recorded. We used an overall α of 0.05 for both the primary and secondary analyses; the secondary analyses were Bonferroni corrected to control for multiple comparisons. The median (interquartile range Q1 to Q3) time to perform the femoral nerve catheter placement was 118 (100 to 150) s with Infiniti Plus and 177 (130 to 236) s without Infiniti Plus. Infiniti Plus significantly reduced the time spent performing femoral nerve catheterisation, with estimated ratio of means [(95% confidence interval), P value] of 0.67 [(0.60 to 0.75), P < 0.001] with Infiniti Plus compared with no Infiniti Plus. However, Infiniti Plus had no effect on the odds of a successful femoral nerve catheter placement, number of attempts or percentage of perfect needle visibility. We found that the use of Infiniti Plus decreased the median time to successfully place a femoral nerve catheter by 33% compared with not using Infiniti Plus. This difference may be more apparent to clinicians undertaking this procedure less often or by those in training as our team was very experienced, had been trained in the technique and was working in a hospital with a large caseload. Clinicaltrials.gov identifier: NCT02080481.

Comparison of the development of performance skills in ultrasound-guided regional anesthesia simulations with different phantom models.

PubMed

Liu, Yang; Glass, Nancy L; Glover, Chris D; Power, Robert W; Watcha, Mehernoor F

2013-12-01

Ultrasound-guided regional anesthesia (UGRA) skills are traditionally obtained by supervised performance on patients, but practice on phantom models improves success. Currently available models are expensive or use perishable products, for example, olive-in-chicken breasts (OCB). We constructed 2 inexpensive phantom (transparent and opaque) models with readily available nonperishable products and compared the process of learning UGRA skills by novice practitioners on these models with the OCB model. Three experts first established criteria for a satisfactory completion of the simulated UGRA task in the 3 models. Thirty-six novice trainees (<20 previous UGRA experience) were randomly assigned to perform a UGRA task on 1 of 3 models-the transparent, opaque, and OCB models, where the hyperechoic target was identified, a needle was advanced to it under ultrasound guidance, fluid was injected, and images were saved. We recorded the errors during task completion, number of attempts and needle passes, and the time for target identification and needle placement until the predetermined benchmark of 3 consecutive successful UGRA simulations was accomplished. The number of errors, needle passes, and time for task completion per attempt progressively decreased in all 3 groups. However, failure to identify the target and to visualize the needle on the ultrasound image occurred more frequently with the OCB model. The time to complete simulator training was shortest with the transparent model, owing to shorter target identification times. However, trainees were less likely to agree strongly that this model was realistic for teaching UGRA skills. Training on inexpensive synthetic simulation models with no perishable products permits learning of UGRA skills by novices. The OCB model has disadvantages of containing potentially infective material, requires refrigeration, cannot be used after multiple needle punctures, and is associated with more failures during simulated UGRA. Direct visualization of the target in the transparent model allows the trainee to focus on needle insertion skills, but the opaque model may be more realistic for learning target identification skills required when UGRA is performed on real patients in the operating room.

Laparoscopic access with a visualizing trocar.

PubMed

Wolf, J S

1997-01-01

Although useful in most situations, there are several inherent disadvantages of the standard laparoscopic access techniques of Veress needle insertion and Hasson-type cannula placement. Veress needle placement may be hazardous in patients at high risk for intraabdominal adhesions and difficult in patients who are obese. The usual alternative, the Hasson-type cannula, often does not provide a good gas seal. As another option, the use of a visualizing trocar (OPTIVIEW) has proven to be effective in the initial experience at the University of Michigan. The inner trocar of the visualizing trocar is hollow except for a clear plastic conical tip with two external ridges. The trocar-cannula assembly is passed through tissue layers to enter the operative space under direct vision from a 10-mm zero-degree laparoscope placed into the trocar. Results suggest that this technique is an excellent alternative to Veress needle placement when laparoscopic access is likely to be hazardous or difficult.

Comparison of Successful Spinal Needle Placement Between Crossed-Leg Sitting Position and Traditional Sitting Position in Patients Undergoing Urology Surgery

PubMed Central

Manggala, Sidharta K.; Tantri, Aida R.; Satoto, Darto

2016-01-01

Background The patient’s position during spinal anesthesia administration plays a major role in the success of spinal needle insertion into the subarachnoid space. The traditional sitting position (TSP) is the standard position for spinal anesthesia administration, but the success rate for spinal anesthesia administration in the TSP is still quite low. The crossed-leg sitting position (CLSP) is one of the alternative positions for the administration of spinal anesthesia, which can increase the degree of lumbar flexion. Objectives This study aimed to compare successful spinal needle placement to patients in the CLSP and patients in the TSP prior to undergoing urology surgery. Methods This study was a non-blinded, randomized controlled trial in patients undergoing spinal anesthesia for urologic procedures from March-October, 2015 in the central national hospital Dr. Cipto Mangunkusumo, Indonesia. After obtaining approval from the FMUI – RSCM (Faculty of Medicine Universitas Indonesia – Rumah Sakit Dr. Cipto Mangunkusumo) Ethical Committee and informed consent from patients, 211 subjects were allocated into two groups: the CLSP group (n = 105) and the TSP group (n = 106). The proportion of successful spinal needle placement to the subarachnoid space, ease of landmark palpation, and the number of needle-bone contacts in both groups were then assessed and analyzed. Results The rate of first-time successful spinal needle insertion was not significantly different between the CLSP and TSP groups (62.9% versus 55.7%, P > 0.05). Ease of landmark palpation in the CLSP group was not significantly different from that in the TSP group (86.7% versus 76.4%, P > 0.05). The number of needle-bone contacts in both groups were not significantly different (P > 0.05). The complication rates were similar in both groups. Conclusions The rate of successful spinal needle placement in the CLSP group was not significantly different from that in the TSP group in patients undergoing urology surgery. The CLSP can be used as an alternative sitting position for administration of spinal anesthesia. PMID:27843785

Toward realistic radiofrequency ablation of hepatic tumors 3D simulation and planning

NASA Astrophysics Data System (ADS)

Villard, Caroline; Soler, Luc; Gangi, Afshin; Mutter, Didier; Marescaux, Jacques

2004-05-01

Radiofrequency ablation (RFA) has become an increasingly used technique in the treatment of patients with unresectable hepatic tumors. Evaluation of vascular architecture, post-RFA tissue necrosis prediction, and the choice of a suitable needle placement strategy using conventional radiological techniques remain difficult. In an attempt to enhance the safety of RFA, a 3D simulator and treatment planning tool, that simulates the necrosis of the treated area, and proposes an optimal placement for the needle, has been developed. From enhanced spiral CT scans with 2 mm cuts, 3D reconstructions of patients with liver metastases are automatically generated. Virtual needles can be added to the 3D scene, together with their corresponding zones of necrosis that are displayed as a meshed spheroids representing the 60° C isosurface. The simulator takes into account the cooling effect of local vessels greater than 3mm in diameter, making necrosis shapes more realistic. Using a voxel-based algorithm, RFA spheroids are deformed following the shape of the vessels, extended by an additional cooled area. This operation is performed in real-time, allowing updates while needle is adjusted. This allows to observe whether the considered needle placement strategy would burn the whole cancerous zone or not. Planned needle positioning can also be automatically generated by the software to produce complete destruction of the tumor with a 1 cm margin, with maximum respect of the healthy liver and of all major extrahepatic and intrahepatic structures to avoid. If he wishes, the radiologist can select on the skin an insertion window for the needle, focusing the research of the trajectory.

A review of the benefits and pitfalls of phantoms in ultrasound-guided regional anesthesia.

PubMed

Hocking, Graham; Hebard, Simon; Mitchell, Christopher H

2011-01-01

With the growth of ultrasound-guided regional anesthesia, so has the requirement for training tools to practice needle guidance skills and evaluate echogenic needles. Ethically, skills in ultrasound-guided needle placement should be gained in a phantom before performance of nerve blocks on patients in clinical practice. However, phantom technology is varied, and critical evaluation of the images is needed to understand their application to clinical use. Needle visibility depends on the echogenicity of the needle relative to the echogenicity of the tissue adjacent the needle. We demonstrate this point using images of echogenic and nonechogenic needles in 5 different phantoms at both shallow angles (20 degrees) and steep angles (45 degrees). The echogenicity of phantoms varies enormously, and this impacts on how needles are visualized. Water is anechoic, making all needles highly visible, but does not fix the needle to allow practice placement. Gelatin phantoms and Blue Phantoms provide tactile feedback but have very low background echogenicity, which greatly exaggerates needle visibility. This makes skill acquisition easier but can lead to false confidence in regard to clinical ability. Fresh-frozen cadavers retain much of the textural feel of live human tissue and are nearly as echogenic. Similar to clinical practice, this makes needles inserted at steep angles practically invisible, unless they are highly echogenic. This review describes the uses and pitfalls of phantoms that have been described or commercially produced. Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine

Cadaveric validation of dry needle placement in the lateral pterygoid muscle.

PubMed

Mesa-Jiménez, Juan A; Sánchez-Gutiérrez, Jesús; de-la-Hoz-Aizpurua, José L; Fernández-de-las-Peñas, César

2015-02-01

The aim of this anatomical study was to determine if a needle is able to reach the lateral pterygoid muscle during the application of dry needling technique. A dry needling approach using 2 needles of 50 to 60 mm in length, one inserted over the zygomatic process posterior at the obituary arch (for the superior head) and other inserted below the zygomatic process between the mandibular condyle and the coronoid process (for the inferior head), was proposed. A progressive dissection into 3 stages was conducted into 2 heads of fresh male cadavers. First, dry needling of the lateral pterygoid muscle was applied on the cadaver. Second, a block dissection containing the lateral pterygoid was harvested. Finally, the ramus of the mandible was sectioned by osteotomy to visualize the lateral pterygoid muscle with the needle placements. With the needles inserted into the cadaver, the block dissection revealed that the superior needle reached the superior (sphenoid) head of the lateral pterygoid muscle and the inferior needle reached the inferior (pterygoid) head of the muscle. At the final stage of the dissection, when the ramus of the mandible was sectioned by osteotomy, it was revealed that the superior needle entered into the belly of the superior head of the lateral pterygoid muscle. This anatomical study supports that dry needling technique for the lateral pterygoid muscle can be properly conducted with the proposed approach. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Pneumatically Operated MRI-Compatible Needle Placement Robot for Prostate Interventions

PubMed Central

Fischer, Gregory S.; Iordachita, Iulian; Csoma, Csaba; Tokuda, Junichi; Mewes, Philip W.; Tempany, Clare M.; Hata, Nobuhiko; Fichtinger, Gabor

2011-01-01

Magnetic Resonance Imaging (MRI) has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot performs needle insertion under real-time 3T MR image guidance; workspace requirements, MR compatibility, and workflow have been evaluated on phantoms. The paper explains the robot mechanism and controller design and presents results of preliminary evaluation of the system. PMID:21686038

Pneumatically Operated MRI-Compatible Needle Placement Robot for Prostate Interventions.

PubMed

Fischer, Gregory S; Iordachita, Iulian; Csoma, Csaba; Tokuda, Junichi; Mewes, Philip W; Tempany, Clare M; Hata, Nobuhiko; Fichtinger, Gabor

2008-06-13

Magnetic Resonance Imaging (MRI) has potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. The strong magnetic field prevents the use of conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot performs needle insertion under real-time 3T MR image guidance; workspace requirements, MR compatibility, and workflow have been evaluated on phantoms. The paper explains the robot mechanism and controller design and presents results of preliminary evaluation of the system.

SU-F-J-10: Sliding Mode Control of a SMA Actuated Active Flexible Needle for Medical Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podder, T

Purpose: In medical interventional procedures such as brachytherapy, ablative therapies and biopsy precise steering and accurate placement of needles are very important for anatomical obstacle avoidance and accurate targeting. This study presents the efficacy of a sliding mode controller for Shape Memory Alloy (SMA) actuated flexible needle for medical procedures. Methods: Second order system dynamics of the SMA actuated active flexible needle was used for deriving the sliding mode control equations. Both proportional-integral-derivative (PID) and adaptive PID sliding mode control (APIDSMC) algorithms were developed and implemented. The flexible needle was attached at the end of a 6 DOF robotic system.more » Through LabView programming environment, the control commands were generated using the PID and APIDSMC algorithms. Experiments with artificial tissue mimicking phantom were performed to evaluate the performance of the controller. The actual needle tip position was obtained using an electromagnetic (EM) tracking sensor (Aurora, NDI, waterloo, Canada) at a sampling period of 1ms. During experiment, external disturbances were created applying force and thermal shock to investigate the robustness of the controllers. Results: The root mean square error (RMSE) values for APIDSMC and PID controllers were 0.75 mm and 0.92 mm, respectively, for sinusoidal reference input. In the presence of external disturbances, the APIDSMC controller showed much smoother and less overshooting response compared to that of the PID controller. Conclusion: Performance of the APIDSMC was superior to the PID controller. The APIDSMC was proved to be more effective controller in compensating the SMA uncertainties and external disturbances with clinically acceptable thresholds.« less

TU-H-CAMPUS-JeP3-05: Adaptive Determination of Needle Sequence HDR Prostate Brachytherapy with Divergent Needle-By-Needle Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borot de Battisti, M; Maenhout, M; Lagendijk, J J W

Purpose: To develop a new method which adaptively determines the optimal needle insertion sequence for HDR prostate brachytherapy involving divergent needle-by-needle dose delivery by e.g. a robotic device. A needle insertion sequence is calculated at the beginning of the intervention and updated after each needle insertion with feedback on needle positioning errors. Methods: Needle positioning errors and anatomy changes may occur during HDR brachytherapy which can lead to errors in the delivered dose. A novel strategy was developed to calculate and update the needle sequence and the dose plan after each needle insertion with feedback on needle positioning errors. Themore » dose plan optimization was performed by numerical simulations. The proposed needle sequence determination optimizes the final dose distribution based on the dose coverage impact of each needle. This impact is predicted stochastically by needle insertion simulations. HDR procedures were simulated with varying number of needle insertions (4 to 12) using 11 patient MR data-sets with PTV, prostate, urethra, bladder and rectum delineated. Needle positioning errors were modeled by random normally distributed angulation errors (standard deviation of 3 mm at the needle’s tip). The final dose parameters were compared in the situations where the needle with the largest vs. the smallest dose coverage impact was selected at each insertion. Results: Over all scenarios, the percentage of clinically acceptable final dose distribution improved when the needle selected had the largest dose coverage impact (91%) compared to the smallest (88%). The differences were larger for few (4 to 6) needle insertions (maximum difference scenario: 79% vs. 60%). The computation time of the needle sequence optimization was below 60s. Conclusion: A new adaptive needle sequence determination for HDR prostate brachytherapy was developed. Coupled to adaptive planning, the selection of the needle with the largest dose coverage impact increases chances of reaching the clinical constraints. M. Borot de Battisti is funded by Philips Medical Systems Nederland B.V.; M. Moerland is principal investigator on a contract funded by Philips Medical Systems Nederland B.V.; G. Hautvast and D. Binnekamp are fulltime employees of Philips Medical Systems Nederland B.V.« less

Percutaneous needle placement using laser guidance: a practical solution

NASA Astrophysics Data System (ADS)

Xu, Sheng; Kapoor, Ankur; Abi-Jaoudeh, Nadine; Imbesi, Kimberly; Hong, Cheng William; Mazilu, Dumitru; Sharma, Karun; Venkatesan, Aradhana M.; Levy, Elliot; Wood, Bradford J.

2013-03-01

In interventional radiology, various navigation technologies have emerged aiming to improve the accuracy of device deployment and potentially the clinical outcomes of minimally invasive procedures. While these technologies' performance has been explored extensively, their impact on daily clinical practice remains undetermined due to the additional cost and complexity, modification of standard devices (e.g. electromagnetic tracking), and different levels of experience among physicians. Taking these factors into consideration, a robotic laser guidance system for percutaneous needle placement is developed. The laser guidance system projects a laser guide line onto the skin entry point of the patient, helping the physician to align the needle with the planned path of the preoperative CT scan. To minimize changes to the standard workflow, the robot is integrated with the CT scanner via optical tracking. As a result, no registration between the robot and CT is needed. The robot can compensate for the motion of the equipment and keep the laser guide line aligned with the biopsy path in real-time. Phantom experiments showed that the guidance system can benefit physicians at different skill levels, while clinical studies showed improved accuracy over conventional freehand needle insertion. The technology is safe, easy to use, and does not involve additional disposable costs. It is our expectation that this technology can be accepted by interventional radiologists for CT guided needle placement procedures.

Patient identification error among prostate needle core biopsy specimens--are we ready for a DNA time-out?

PubMed

Suba, Eric J; Pfeifer, John D; Raab, Stephen S

2007-10-01

Patient identification errors in surgical pathology often involve switches of prostate or breast needle core biopsy specimens among patients. We assessed strategies for decreasing the occurrence of these uncommon and yet potentially catastrophic events. Root cause analyses were performed following 3 cases of patient identification error involving prostate needle core biopsy specimens. Patient identification errors in surgical pathology result from slips and lapses of automatic human action that may occur at numerous steps during pre-laboratory, laboratory and post-laboratory work flow processes. Patient identification errors among prostate needle biopsies may be difficult to entirely prevent through the optimization of work flow processes. A DNA time-out, whereby DNA polymorphic microsatellite analysis is used to confirm patient identification before radiation therapy or radical surgery, may eliminate patient identification errors among needle biopsies.

Measurement of bio-impedance with a smart needle to confirm percutaneous kidney access.

PubMed

Hernandez, D J; Sinkov, V A; Roberts, W W; Allaf, M E; Patriciu, A; Jarrett, T W; Kavoussi, L R; Stoianovici, D

2001-10-01

The traditional method of percutaneous renal access requires freehand needle placement guided by C-arm fluoroscopy, ultrasonography, or computerized tomography. This approach provides limited objective means for verifying successful access. We developed an impedance based percutaneous Smart Needle system and successfully used it to confirm collecting system access in ex vivo porcine kidneys. The Smart Needle consists of a modified 18 gauge percutaneous access needle with the inner stylet electrically insulated from the outer sheath. Impedance is measured between the exposed stylet tip and sheath using Model 4275 LCR meter (Hewlett-Packard, Sunnyvale, California). An ex vivo porcine kidney was distended by continuous gravity infusion of 100 cm. water saline from a catheter passed through the parenchyma into the collecting system. The Smart Needle was gradually inserted into the kidney to measure depth precisely using a robotic needle placement system, while impedance was measured continuously. The Smart Needle was inserted 4 times in each of 4 kidneys. When the needle penetrated the distended collecting system in 11 of 16 attempts, a characteristic sharp drop in resistivity was noted from 1.9 to 1.1 ohm m. Entry into the collecting system was confirmed by removing the stylet and observing fluid flow from the sheath. This characteristic impedance change was observed only at successful entry into the collecting system. A characteristic sharp drop in impedance signifies successful entry into the collecting system. The Smart Needle system may prove useful for percutaneous kidney access.

Head-mounted display augmented reality to guide pedicle screw placement utilizing computed tomography.

PubMed

Gibby, Jacob T; Swenson, Samuel A; Cvetko, Steve; Rao, Raj; Javan, Ramin

2018-06-22

Augmented reality has potential to enhance surgical navigation and visualization. We determined whether head-mounted display augmented reality (HMD-AR) with superimposed computed tomography (CT) data could allow the wearer to percutaneously guide pedicle screw placement in an opaque lumbar model with no real-time fluoroscopic guidance. CT imaging was obtained of a phantom composed of L1-L3 Sawbones vertebrae in opaque silicone. Preprocedural planning was performed by creating virtual trajectories of appropriate angle and depth for ideal approach into the pedicle, and these data were integrated into the Microsoft HoloLens using the Novarad OpenSight application allowing the user to view the virtual trajectory guides and CT images superimposed on the phantom in two and three dimensions. Spinal needles were inserted following the virtual trajectories to the point of contact with bone. Repeat CT revealed actual needle trajectory, allowing comparison with the ideal preprocedural paths. Registration of AR to phantom showed a roughly circular deviation with maximum average radius of 2.5 mm. Users took an average of 200 s to place a needle. Extrapolation of needle trajectory into the pedicle showed that of 36 needles placed, 35 (97%) would have remained within the pedicles. Needles placed approximated a mean distance of 4.69 mm in the mediolateral direction and 4.48 mm in the craniocaudal direction from pedicle bone edge. To our knowledge, this is the first peer-reviewed report and evaluation of HMD-AR with superimposed 3D guidance utilizing CT for spinal pedicle guide placement for the purpose of cannulation without the use of fluoroscopy.

SU-D-213AB-06: Surface Texture and Insertion Speed Effect on Needle Friction.

PubMed

Abdullah, A; Golecki, C; Barnett, A; Moore, J

2012-06-01

High frictional forces between the needle surface and tissue cause tissue deflection which hinders accurate needle placement for procedures such as brachytherapy and needle biopsy. Accurate needle placement isimportant to maximize procedure efficacy. This work investigates how needle surface roughness and insertion speed affect the frictional forcebetween a needle and tissue. A friction experiment was conducted to measure the force of friction between bovine liver and three 11 gauge needles having Ra surface roughness of 3.43, 1.33, and 0.2 μm. Each of the three needles were mounted on a linear slide and were advanced and retracted through bovine liver at speeds of 50, 100, 150, and 200 mm/s for a total of 12 trials. In each trial the needle was advanced and retracted in 10 cycles producing a steady state insertion force and a steady state retraction force for each cycle. A force sensor connecting the needle to the linear slide recorded the resistance force of the needle sliding through the liver. The liver was mounted in a box with a pneumatic cylinder which compressed the liver sample by 11.65 kPa. The roughest needle (Ra = 3.43 μm) on average produced 68, 73, 74, and 73% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200mm/s, respectively. The second roughest needle (Ra = 1.33 μm) on average produced 25, 45, 60 and 64% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200 mm/s, respectively. Rougher needle surface texture and higher insertion speed reduced frictional forces between the tissue and the needle. Future studies will examine how frictional forces can be modeled and predicted given surface texture and insertion speed. © 2012 American Association of Physicists in Medicine.

Motorized fusion guided prostate biopsy: phantom study

NASA Astrophysics Data System (ADS)

Seifabadi, Reza; Xu, Sheng; Aalamifar, Fereshteh; Pinto, Peter; Wood, Bradford J.

2017-03-01

Purpose: Fusion of Magnetic Resonance Imaging (MRI) with intraoperative real-time Ultrasound (US) during prostate biopsy has significantly improved the sensitivity of transrectal ultrasound (TRUS) guided cancer detection. Currently, sweeping of the TRUS probe to build a 3D volume as part of the fusion process and the TRUS probe manipulation for needle guidance are both done manually. A motorized, joystick controlled, probe holder was custom fabricated that can potentially reduce inter-operator variability, provide standardization of needle placement, improve repeatability and uniformity of needle placement, which may have impacts upon the learning curve after clinical deployment of this emerging approach. Method: a 2DOF motorized probe holder was designed to provide translation and rotation of a triplane TRUS end firing probe for prostate biopsy. The probe holder was joystick controlled and can assist manipulation of the probe during needle insertion as well as in acquiring a smoother US 2D to 3D sweep in which the 3D US volume for fusion is built. A commercial MRI-US fusion platform was used. Three targets were specified on MR image of a commercial prostate phantom. After performing the registration, two operators performed targeting, once manually and once with the assistance of the motorized probe holder. They repeated these tasks 5 times resulting in a total of 30 targeting events. Time of completion and mechanical error i.e. distance of the target from the needle trajectory in the software user interface were measured. Repeatability in reaching a given target in a systematic and consistent way was measured using a scatter plot showing all targets in the US coordinate system. Pearson product-moment correlation coefficient (PPMCC) was used to demonstrate the probe steadiness during targeting. Results: the completion time was 25+/-17 sec, 25+/-24 sec, and 27+/-15 sec for free hand and 24+/-10 sec, 22.5+/-10 sec, and 37+/-10 sec for motorized insertion, for target 1, 2, and 3, respectively. The mechanical error was 0.75+/-0.4 mm, 0.45+/-0.4 mm, and 0.55+/-0.4 mm, for free hand approach while it was 1.0+/-0.57 mm, 0.45+/-0.4 mm, and 0.35+/-0.25 mm, for motorized approach, for target 1, 2, and 3, respectively. PPMCC remained almost at 1.0 for the motorized approach while having a variation between 0.9 and 1.0 for the free hand approach. Conclusions: motorized fusion guided prostate biopsy in a phantom study was feasible and non-inferior or comparable to the free hand manual approach in terms of accuracy and speed of targeting, while being superior in terms of repeatability and steadiness.

CT-Guided Placement of a Drainage Catheter Within a Pelvic Abscess Using a Transsacral Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iguchi, Toshihiro; Asami, Shinya; Kubo, Shinichiro

2007-11-15

A 66-year-old man underwent CT-guided drainage catheter placement within a pelvic abscess with a diameter of 46 mm. We performed the drainage by a transsacral approach because it was considered the safest and most feasible approach. An 8G bone marrow biopsy needle was used to penetrate the sacrum to create a path for subsequent drainage catheter insertion. After withdrawal of the biopsy needle, a 6 Fr catheter was advanced into the abscess cavity through the path using the Seldinger technique. Except for bearable pain, no procedure-related complications occurred. Twenty-nine days after the placement, the catheter was withdrawn safely and themore » abscess cavity had shrunk remarkably.« less

Intravascular flow detection during transforaminal epidural injections: a prospective assessment.

PubMed

El Abd, Omar Hamman; Amadera, Joao Eduardo Daud; Pimentel, Daniel Camargo; Pimentel, Thais Spacov Camargo

2014-01-01

Transforaminal epidural steroid injections (TFESI) are a mainstay in the treatment of spine pain. Though this commonly performed procedure is generally felt to be safe, devastating complications following inadvertent intra-arterial injections of particulate steroid have been reported. The use of digital subtraction angiography (DSA) has been suggested as a means of detecting intra-arterial needle placements prior to medication injection. To examine the efficacy of DSA in detecting intra-arterial needle placements during TFESI. Prospective cohort study evaluating the impact of DSA on detecting intra-arterial needle placements during TFESI. We enrolled 150 consecutive patients presenting to a university-affiliated spine center with discogenic and/or radicular symptoms affecting the cervical, lumbar, and sacral regions. For each injection, prior to imaging with DSA, traditional methods for vascular penetration detection were employed, including the identification of blood in the needle hub (flash), negative aspiration of blood prior to injection, and live fluoroscopic injection of contrast. Once these tests were performed and negative for signs of intra-arterial needle placement, DSA imaging was utilized prior to medication administration for identification of vascular flow. A total number of 222 TFESI were performed, 41 injections at the cervical levels (18.47%), 113 at the lumbar levels (50.9%), and 68 at the sacral levels (30.36%). Flash was observed in 13 injections performed (5.85% of the total number of injections): one (0.45%) in the cervical, 2 (0.9%) in the lumbar, and 10 (4.5%) in the sacral levels. In 11 TFESI blood aspiration was obtained (4.95% of all injections): 3 (1.3%) in cervical, 4 (1.8%) in lumbar, and 4 (1.8%) in sacral injections. Live fluoroscopy during contrast injection detected 46 (20.72%) intravascular flow patterns: 7 (3.1%) cervical, 17 (7.6%) lumbar, and 22 (9.9%) sacral. DSA identified an additional 5 intravascular injections after all previous steps had resulted in negative vascular penetration signs, which accounted for 2.25% of all injections. This is a prospective, single-center study with a relatively small number of patients and no control group. DSA detected additional 5.26% intravascular needle placements following traditional methods. Our findings also support other studies that conclude TFESI are generally a safe procedure. We recommend that special attention should be paid to the sacral injections as vascular penetration was statistically higher than at other levels.

Motion compensation for MRI-compatible patient-mounted needle guide device: estimation of targeting accuracy in MRI-guided kidney cryoablations

NASA Astrophysics Data System (ADS)

Tokuda, Junichi; Chauvin, Laurent; Ninni, Brian; Kato, Takahisa; King, Franklin; Tuncali, Kemal; Hata, Nobuhiko

2018-04-01

Patient-mounted needle guide devices for percutaneous ablation are vulnerable to patient motion. The objective of this study is to develop and evaluate a software system for an MRI-compatible patient-mounted needle guide device that can adaptively compensate for displacement of the device due to patient motion using a novel image-based automatic device-to-image registration technique. We have developed a software system for an MRI-compatible patient-mounted needle guide device for percutaneous ablation. It features fully-automated image-based device-to-image registration to track the device position, and a device controller to adjust the needle trajectory to compensate for the displacement of the device. We performed: (a) a phantom study using a clinical MR scanner to evaluate registration performance; (b) simulations using intraoperative time-series MR data acquired in 20 clinical cases of MRI-guided renal cryoablations to assess its impact on motion compensation; and (c) a pilot clinical study in three patients to test its feasibility during the clinical procedure. FRE, TRE, and success rate of device-to-image registration were mm, mm, and 98.3% for the phantom images. The simulation study showed that the motion compensation reduced the targeting error for needle placement from 8.2 mm to 5.4 mm (p  <  0.0005) in patients under general anesthesia (GA), and from 14.4 mm to 10.0 mm () in patients under monitored anesthesia care (MAC). The pilot study showed that the software registered the device successfully in a clinical setting. Our simulation study demonstrated that the software system could significantly improve targeting accuracy in patients treated under both MAC and GA. Intraprocedural image-based device-to-image registration was feasible.

Electromagnetic-Tracked Biopsy under Ultrasound Guidance: Preliminary Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakime, Antoine, E-mail: thakime@yahoo.com; Deschamps, Frederic; Marques De Carvalho, Enio Garcia

2012-08-15

Purpose: This study was designed to evaluate the accuracy and safety of electromagnetic needle tracking for sonographically guided percutaneous liver biopsies. Methods: We performed 23 consecutive ultrasound-guided liver biopsies for liver nodules with an electromagnetic tracking of the needle. A sensor placed at the tip of a sterile stylet (18G) inserted in a coaxial guiding trocar (16G) used for biopsy was localized in real time relative to the ultrasound imaging plane, thanks to an electromagnetic transmitter and two sensors on the ultrasound probe. This allows for electronic display of the needle tip location and the future needle path overlaid onmore » the real-time ultrasound image. Distance between needle tip position and its electronic display, number of needle punctures, number of needle pull backs for redirection, technical success (needle positioned in the target), diagnostic success (correct histopathology result), procedure time, and complication were evaluated according to lesion sizes, depth and location, operator experience, and 'in-plane' or 'out-of-plane' needle approach. Results: Electronic display was always within 2 mm from the real position of the needle tip. The technical success rate was 100%. A single needle puncture without repuncture was used in all patients. Pull backs were necessary in six patients (26%) to obtain correct needle placement. The overall diagnostic success rate was 91%. The overall true-positive, true-negative, false-negative, and failure rates of the biopsy were 100% (19/19) 100% (2/2), 0% (0/23), and 9% (2/23). The median total procedure time from the skin puncture to the needle in the target was 30 sec (from 5-60 s). Lesion depth and localizations, operator experience, in-plane or out-of-plane approach did not affect significantly the technical, diagnostic success, or procedure time. Even when the tumor size decreased, the procedure time did not increase. Conclusions: Electromagnetic-tracked biopsy is accurate to determine needle tip position and allows fast and accurate needle placement in targeted liver nodules.« less

Fusion of electromagnetic trackers to improve needle deflection estimation: simulation study.

PubMed

Sadjadi, Hossein; Hashtrudi-Zaad, Keyvan; Fichtinger, Gabor

2013-10-01

We present a needle deflection estimation method to anticipate needle bending during insertion into deformable tissue. Using limited additional sensory information, our approach reduces the estimation error caused by uncertainties inherent in the conventional needle deflection estimation methods. We use Kalman filters to combine a kinematic needle deflection model with the position measurements of the base and the tip of the needle taken by electromagnetic (EM) trackers. One EM tracker is installed on the needle base and estimates the needle tip position indirectly using the kinematic needle deflection model. Another EM tracker is installed on the needle tip and estimates the needle tip position through direct, but noisy measurements. Kalman filters are then employed to fuse these two estimates in real time and provide a reliable estimate of the needle tip position, with reduced variance in the estimation error. We implemented this method to compensate for needle deflection during simulated needle insertions and performed sensitivity analysis for various conditions. At an insertion depth of 150 mm, we observed needle tip estimation error reductions in the range of 28% (from 1.8 to 1.3 mm) to 74% (from 4.8 to 1.2 mm), which demonstrates the effectiveness of our method, offering a clinically practical solution.

Radiofrequency ablation of hepatic tumors: simulation, planning, and contribution of virtual reality and haptics.

PubMed

Villard, Caroline; Soler, Luc; Gangi, Afshin

2005-08-01

For radiofrequency ablation (RFA) of liver tumors, evaluation of vascular architecture, post-RFA necrosis prediction, and the choice of a suitable needle placement strategy using conventional radiological techniques remain difficult. In an attempt to enhance the safety of RFA, a 3D simulator, treatment planning, and training tool, that simulates the insertion of the needle, the necrosis of the treated area, and proposes an optimal needle placement, has been developed. The 3D scenes are automatically reconstructed from enhanced spiral CT scans. The simulator takes into account the cooling effect of local vessels greater than 3 mm in diameter, making necrosis shapes more realistic. Optimal needle positioning can be automatically generated by the software to produce complete destruction of the tumor, with maximum respect of the healthy liver and of all major structures to avoid. We also studied how the use of virtual reality and haptic devices are valuable to make simulation and training realistic and effective.

A method for improving the accuracy of stereotaxic procedures in monkeys using implanted fiducial markers in CT scans that also serve as anchor points in a stereotaxic frame.

PubMed

Risher, D W; Zhang, X; Kostarczyk, E; Gokin, A P; Honda, C N; Giesler, G J

1997-04-25

We developed a relatively inexpensive method for stereotaxic placement of electrodes or needles in the brains of monkeys. Steel balls were affixed to the skulls of monkeys. These balls served as fiducial markers and were also used as points at which the monkey's skull was held in a modified stereotaxic apparatus. Computed tomography (CT) was used to establish the location of an injection target with respect to the fiducial markers. A computer program related the CT coordinates to stereotaxic coordinates. These were used to direct an electrode marker toward a target in the hypothalamus. With the marker left in place, the monkey was removed from the stereotaxic frame and a second CT scan was performed. Corrections for errors in marker placement were made and retrograde tracers were injected. This procedure was found to be more accurate and reliable than conventional stereotaxic procedures. The accuracy and repeatability of the technique were also established using a phantom model of a monkey's skull. Two important advantages of this method are that animals can be repeatedly placed into the stereotaxic frame in precisely the same position and that there are many opportunities during the procedure to check for and correct errors.

Development of a high frequency single-element ultrasound needle transducer for anesthesia delivery

NASA Astrophysics Data System (ADS)

Ameri, Golafsoun; Son, Jungik; Liang, Jingwei; Foster, F. Stuart; Ganapathy, Sugantha; Peters, Terry M.

2017-03-01

Epidural anesthesia is one of the most commonly used and yet challenging techniques employed for pain management and anesthesia delivery. The major complications of this procedure are due to accidental dural puncture, with an incidence of 1-3%, which could lead to both temporary and irreversible permanent neurological complications. Needle placement under ultrasound (US) guidance has received increasing interest for improving needle placement accuracy. However, poor needle visibility in US, difficulties in displaying relevant anatomical structure such as dura mater due to attenuation and bone shadowing, and image interpretation variability among users pose significant hurdles for any US guidance system. As a result, US guidance for epidural injections has not been widely adopted for everyday use for the performance of neuraxial blocks. The difficulties in localizing the ligamentum flavum and dura with respect to the needle tip can be addressed by integrating A-mode US, provided by a single-element transducer at the needle tip, into the B-mode US guidance system. We have taken the first steps towards providing such a guidance system. Our goal is to improve the safety of this procedure with minimal changes to the clinical workflow. This work presents the design and development of a 20 MHz single-element US transducer housed at the tip of a 19 G needle hypodermic tube, which can fit inside an epidural introducer needle. In addition, the results from initial transducer characterization tests and performance evaluation of the transducer in a euthanized porcine model are provided.

An MRI-Guided Telesurgery System Using a Fabry-Perot Interferometry Force Sensor and a Pneumatic Haptic Device.

PubMed

Su, Hao; Shang, Weijian; Li, Gang; Patel, Niravkumar; Fischer, Gregory S

2017-08-01

This paper presents a surgical master-slave teleoperation system for percutaneous interventional procedures under continuous magnetic resonance imaging (MRI) guidance. The slave robot consists of a piezoelectrically actuated 6-degree-of-freedom (DOF) robot for needle placement with an integrated fiber optic force sensor (1-DOF axial force measurement) using the Fabry-Perot interferometry (FPI) sensing principle; it is configured to operate inside the bore of the MRI scanner during imaging. By leveraging the advantages of pneumatic and piezoelectric actuation in force and position control respectively, we have designed a pneumatically actuated master robot (haptic device) with strain gauge based force sensing that is configured to operate the slave from within the scanner room during imaging. The slave robot follows the insertion motion of the haptic device while the haptic device displays the needle insertion force as measured by the FPI sensor. Image interference evaluation demonstrates that the telesurgery system presents a signal to noise ratio reduction of less than 17% and less than 1% geometric distortion during simultaneous robot motion and imaging. Teleoperated needle insertion and rotation experiments were performed to reach 10 targets in a soft tissue-mimicking phantom with 0.70 ± 0.35 mm Cartesian space error.

Intrauterine transfusion with the use of phased array ultrasonography: a new technique.

PubMed

Frigoletto, F D; Birnholz, J C; Rothchild, S B; Finberg, H J; Umansky, I

1978-06-01

Continuous ultrasonic observation of needle placement for aspiration, biopsy, or catheter placement is a novel and specific use of phased array imaging. In the case of IUTx, catheter placement into the fetal peritoneal space is accomplished rapidly, with reduced risk of fetal trauma, and without exposure to ionizing radiation. Experience with 27 transfusions in 11 patients is presented.

Feasibility Study of Needle Placement in Percutaneous Vertebroplasty: Cone-Beam Computed Tomography Guidance Versus Conventional Fluoroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braak, Sicco J., E-mail: sjbraak@gmail.com; Zuurmond, Kirsten, E-mail: kirsten.zuurmond@philips.com; Aerts, Hans C. J., E-mail: hans.cj.aerts@philips.com

2013-08-01

ObjectiveTo investigate the accuracy, procedure time, fluoroscopy time, and dose area product (DAP) of needle placement during percutaneous vertebroplasty (PVP) using cone-beam computed tomography (CBCT) guidance versus fluoroscopy.Materials and MethodsOn 4 spine phantoms with 11 vertebrae (Th7-L5), 4 interventional radiologists (2 experienced with CBCT guidance and two inexperienced) punctured all vertebrae in a bipedicular fashion. Each side was randomization to either CBCT guidance or fluoroscopy. CBCT guidance is a sophisticated needle guidance technique using CBCT, navigation software, and real-time fluoroscopy. The placement of the needle had to be to a specific target point. After the procedure, CBCT was performed tomore » determine the accuracy, procedure time, fluoroscopy time, and DAP. Analysis of the difference between methods and experience level was performed.ResultsMean accuracy using CBCT guidance (2.61 mm) was significantly better compared with fluoroscopy (5.86 mm) (p < 0.0001). Procedure time was in favor of fluoroscopy (7.39 vs. 10.13 min; p = 0.001). Fluoroscopy time during CBCT guidance was lower, but this difference is not significant (71.3 vs. 95.8 s; p = 0.056). DAP values for CBCT guidance and fluoroscopy were 514 and 174 mGy cm{sup 2}, respectively (p < 0.0001). There was a significant difference in favor of experienced CBCT guidance users regarding accuracy for both methods, procedure time of CBCT guidance, and added DAP values for fluoroscopy.ConclusionCBCT guidance allows users to perform PVP more accurately at the cost of higher patient dose and longer procedure time. Because procedural complications (e.g., cement leakage) are related to the accuracy of the needle placement, improvements in accuracy are clinically relevant. Training in CBCT guidance is essential to achieve greater accuracy and decrease procedure time/dose values.« less

The effect of augmented reality training on percutaneous needle placement in spinal facet joint injections.

PubMed

Yeo, Caitlin T; Ungi, Tamas; U-Thainual, Paweena; Lasso, Andras; McGraw, Robert C; Fichtinger, Gabor

2011-07-01

The purpose of this study was to determine if augmented reality image overlay and laser guidance systems can assist medical trainees in learning the correct placement of a needle for percutaneous facet joint injection. The Perk Station training suite was used to conduct and record the needle insertion procedures. A total of 40 volunteers were randomized into two groups of 20. 1) The Overlay group received a training session that consisted of four insertions with image and laser guidance, followed by two insertions with laser overlay only. 2) The Control group received a training session of six classical freehand insertions. Both groups then conducted two freehand insertions. The movement of the needle was tracked during the series of insertions. The final insertion procedure was assessed to determine if there was a benefit to the overlay method compared to the freehand insertions. The Overlay group had a better success rate (83.3% versus 68.4%, p=0.002), and potential for less tissue damage as measured by the amount of needle movement inside the phantom (3077.6 mm(2) versus 5607.9 mm(2) , p =0.01). These results suggest that an augmented reality overlay guidance system can assist medical trainees in acquiring technical competence in a percutaneous needle insertion procedure. © 2011 IEEE

Positional calibration of an ultrasound image-guided robotic breast biopsy system.

PubMed

Nelson, Thomas R; Tran, Amy; Fakourfar, Hourieh; Nebeker, Jakob

2012-03-01

Precision biopsy of small lesions is essential in providing high-quality patient diagnosis and management. Localization depends on high-quality imaging. We have developed a dedicated, fully automatic volume breast ultrasound (US) imaging system for early breast cancer detection. This work focuses on development of an image-guided robotic biopsy system that is integrated with the volume breast US system for performing minimally invasive breast biopsies. The objective of this work was to assess the positional accuracy of the robotic system for breast biopsy. We have adapted a compact robotic arm for performing breast biopsy. The arm incorporates a force torque sensor and is modified to accommodate breast biopsy sampling needles mounted on the robot end effector. Volume breast US images are used as input to a targeting algorithm that provides the physician with control of biopsy device guidance and trajectory optimization. In this work, the positional accuracy was evaluated using (1) a light-emitting diode (LED) mounted on the end effector and (2) a LED mounted on the end of a biopsy needle, each of which was imaged for each robot controller position as part of mapping the positional accuracy throughout a volume that would contain the breast. We measured the error in each location and the cumulative error. Robotic device performance over the volume provided mean accuracy ± SD of 0.76 ± 0.13 mm (end effector) and 0.55 ± 0.13 mm (needle sample location), sufficient for a targeting accuracy within ±1 mm, which is suitable for clinical use. Depth positioning error also was small: 0.38 ± 0.03 mm. Reproducibility was excellent with less than 0.5% variation. Overall accuracy and reproducibility of the compact robotic device were excellent, well within clinical biopsy performance requirements. Volume breast US data provide high-quality input to a biopsy sampling algorithm under physician control. Robotic devices may provide more precise device placement, assisting physicians with biopsy procedures.

Accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints.

PubMed

Siegenthaler, Andreas; Mlekusch, Sabine; Trelle, Sven; Schliessbach, Juerg; Curatolo, Michele; Eichenberger, Urs

2012-08-01

Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control. Sixty volunteers were studied. Ultrasound-imaging was used to place the needle to the bony target of cervical zygapophysial joint nerve blocks. The levels of needle placement were determined randomly (three levels per volunteer). After ultrasound-guided needle placement and application of 0.2 ml contrast dye, fluoroscopic imaging was performed for later evaluation by a blinded pain physician and considered as gold standard. Raw agreement, chance-corrected agreement κ, and chance-independent agreement Φ between the ultrasound-guided placement and the assessment using fluoroscopy were calculated to quantify accuracy. One hundred eighty needles were placed in 60 volunteers. Raw agreement was 87% (95% CI 81-91%), κ was 0.74 (0.64-0.83), and Φ 0.99 (0.99-0.99). Accuracy varied significantly between the different cervical nerves: it was low for the C7 medial branch, whereas all other levels showed very good accuracy. Ultrasound-imaging is an accurate technique for performing cervical zygapophysial joint nerve blocks in volunteers, except for the medial branch blocks of C7.

Evaluation of Magnetic Resonance Imaging-Compatible Needles and Interactive Sequences for Musculoskeletal Interventions Using an Open High-Field Magnetic Resonance Imaging Scanner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wonneberger, Uta, E-mail: uta.wonneberger@charite.d; Schnackenburg, Bernhard, E-mail: bernhard.schnackenburg@philips.co; Streitparth, Florian, E-mail: florian.streitparth@charite.de

2010-04-15

In this article, we study in vitro evaluation of needle artefacts and image quality for musculoskeletal laser-interventions in an open high-field magnetic resonance imaging (MRI) scanner at 1.0T with vertical field orientation. Five commercially available MRI-compatible puncture needles were assessed based on artefact characteristics in a CuSO4 phantom (0.1%) and in human cadaveric lumbar spines. First, six different interventional sequences were evaluated with varying needle orientation to the main magnetic field B0 (0{sup o} to 90{sup o}) in a sequence test. Artefact width, needle-tip error, and contrast-to-noise ratio (CNR) were calculated. Second, a gradient-echo sequence used for thermometric monitoring wasmore » assessed and in varying echo times, artefact width, tip error, and signal-to-noise ratio (SNR) were measured. Artefact width and needle-tip error correlated with needle material, instrument orientation to B0, and sequence type. Fast spin-echo sequences produced the smallest needle artefacts for all needles, except for the carbon fibre needle (width <3.5 mm, tip error <2 mm) at 45{sup o} to B0. Overall, the proton density-weighted spin-echo sequences had the best CNR (CNR{sub Muscle/Needle} >16.8). Concerning the thermometric gradient echo sequence, artefacts remained <5 mm, and the SNR reached its maximum at an echo time of 15 ms. If needle materials and sequences are accordingly combined, guidance and monitoring of musculoskeletal laser interventions may be feasible in a vertical magnetic field at 1.0T.« less

Needle echogenicity in ultrasound-guided lumbar spine injections: a cadaveric study.

PubMed

Gofeld, Michael; Krashin, Daniel L; Ahn, Sangmin

2013-01-01

Echogenicity of regional anesthesia needles has been tested on different preclinical models; however, previous studies were done in an ideal experimental setting utilizing high-frequency insonation and superficially located targets. Because steep-angle deep injections are typically required for spinal and other chronic pain procedures, and low-frequency transducers are used, further feasibility study is warranted. To determine effectiveness of steep-angle deep injections, typically required for spinal and other chronic pain procedures. Experimental laboratory study. Willed Body Program, University of Washington. In-plane lumbar spine procedures with 50° and 70° angles were performed on a human cadaver. The images and video clips of a non-echogenic (Quincke-type) and echogenic (SonoPlex, StimuQuick, and EchoStim) needle placements were presented to 3 blinded assessors who rated the needle visibility on a 4-point scale. The data was statistically analyzed to determine the differences in visibility between the needles with and without the digital image enhancement, and to compare the video clips to captured images. ANOVA analysis demonstrated that overall SonoPlex was significantly better (P = 0.02) than other needles. SonoPlex maintained its superiority in the subset of facet joint injections (P = 0.02), followed by Quincke-type, then the StimuQuik, and EchoStim needles. In deep procedures, EchoStim was comparable with SonoPlex (P = 0.03), and they both were better than the other 2 needles. The enhanced images received higher rates, with a 0.6 point mean improved rating (P = 0). This study is limited by choice of needles, number of experiments performed, and potential postmortem changes of echogenicity. The SonoPlex needle appeared to have better echogenicity in this study. While non-echogenic Quincke-type needle visibility was adequate in superficial placements, it was limited in deep injections. An imaging enhancement is effective in improving needle visibility and should be used whenever possible.

Ozone production of hollow-needle-to-mesh negative corona discharge enhanced by dielectric tube on the needle electrode

NASA Astrophysics Data System (ADS)

Pekárek, Stanislav

2014-12-01

For the hollow-needle-to-mesh negative corona discharge in air, we studied the effect of placing the dielectric tube on the needle electrode and the effect of various positions of the end of this tube with respect to the tip of the needle electrode on the concentration of ozone produced by the discharge, the ozone production yield and the discharge V-A characteristics. We found that the placement of the dielectric tube on the needle electrode with a suitable position of this tube end with respect to the tip of the needle electrode for a particular discharge power led to a more than fourfold increase in the concentration of ozone produced by the discharge and also, for a constant airflow, the ozone production yield.

Comparison of Point Placement by Veterinary Professionals with Different Levels of Acupuncture Training in a Canine Cadaver Model.

PubMed

Yang, Toni; Shmalberg, Justin; Hochman, Lindsay; Miscioscia, Erin; Brumby, Meghan; McKenna, Kelsey; Roth, Amber

2017-10-01

Veterinary acupuncture is becoming increasingly implemented for various disease processes, with growing numbers of veterinarians pursuing advanced training to meet the rising demand for this relatively new intervention. Accurate acupoint placement remains challenging, with individual practitioners relying on varying methods of point identification, often compounded by the transpositional nature of points for companion animals. The aim of this study was to assess for differences in acupuncture needle placement of select points between veterinary professionals with three different levels of acupuncture training in an academic teaching environment. Seven participants placed a total of six acupoints on a canine cadaver. Digital radiography was used to document each participant's point placement. Each participant's point location was then compared to a control "correct" point, and the distance between the two points was measured. A significant difference in placement accuracy was identified between the participants when grouped by training level (p = 0.03). These results indicate that veterinary patients receiving acupuncture treatment from veterinarians with different levels of training may subsequently experience varying effects, although further studies are warranted on more specific acupoint description as well as the clinical implications of needle placement accuracy. Copyright © 2017. Published by Elsevier B.V.

Teleoperated master-slave needle insertion.

PubMed

Abolhassani, Niki; Patel, Rajni V

2009-12-01

Accuracy of needle tip placement and needle tracking in soft tissue are of particular importance in many medical procedures. In recent years, developing autonomous and teleoperated systems for needle insertion has become an active area of research. In this study, needle insertion was performed using a master-slave set-up with multi-degrees of freedom. The effect of force feedback on the accuracy of needle insertion was investigated. In addition, this study compared autonomous, teleoperated and semi-autonomous needle insertion. The results of this study show that incorporation of force feedback can improve teleoperated needle insertion. However, autonomous and semi-autonomous needle insertions, which use feedback from a deflection model, provide significantly better performance. Development of a haptic master-slave needle insertion system, which is capable of performing some autonomous tasks based on feedback from tissue deformation and needle deflection models, can improve the performance of autonomous robotics-based insertions as well as non-autonomous teleoperated manual insertions. Copyright (c) 2009 John Wiley & Sons, Ltd.

Risk of needle stick injuries in health care workers: bad habits (recapping needles) last long.

PubMed

Rogowska-Szadkowska, Dorota; Stanisławowicz, Małgorzata; Chlabicz, Sławomir

2010-01-01

In order to assess the nurses' knowledge concerning the risk of hepatitis B and C viruses or human immunodeficiency virus infection while performing their professional duties, an anonymous questionnaire developed by the authors was distributed in 2008. Surprisingly 64% respondents occasionally recapping needles after injections, although they know the procedures which are obligatory at the ward. The first step in preventing percutaneous injuries should focus on efforts to eliminate the practice of recapping needles, though education and convenient placement of puncture-resistant containers for the disposal of used sharps.

CT-guided thermocouple placement for hyperthermia treatment.

PubMed

Banerian, K G; Roberts, J L; Borrego, J C; Martinez, A

1990-05-01

There is a well-documented synergistic cytotoxic effect when heat is combined with ionizing radiation. An integral component of hyperthermia treatments is the placement of thermocouple probes used for thermal dosimetry. With the surge in interest in the clinical use of hyperthermia, our department is performing an increasing number of thermocouple placements under computed tomographic (CT) guidance. We describe our technique for CT-guided thermocouple placement with two different systems: a trocar introduction system and a peel-away needle introduction system. We discuss the rationale for thermocouple placement, our early experience with this technique, and some potential complications.

Do Superior or Inferior Interlaminar Approach or Bevel Orientation Predispose to Nonepidural Needle Penetration?

PubMed

Koontz, Nicholas A; Wiggins, Richard H; Stoddard, Gregory J; Shah, Lubdha M

2017-10-01

There is a paucity of evidence-based literature regarding the advantages and disadvantages of the interlaminar approach and needle bevel orientation for performing a lumbar interlaminar epidural steroid injection (ESI). The purpose of this study was to determine if superior versus inferior lamina approach, needle bevel tip orientation, or both may predispose to inadvertent nonepidural penetration during lumbar interlaminar ESI. A prospective study was performed of patients with low back pain with or without radicular pain or neurogenic claudication referred for lumbar interlaminar ESI. Two hundred eleven patients were randomized by interlaminar approach (superior vs inferior) and bevel tip orientation (cranial vs caudal). Lumbar interlaminar ESI was performed by six interventionalists of varying levels of experience using fluoroscopic guidance with curved tip epidural needles, using loss-of-resistance technique and confirmation with contrast opacification. Exact Poisson regression was used to model the study outcome. Two hundred twenty-one lumbar interlaminar ESIs were performed on 211 patients, randomized to a superior (n = 121) or inferior lamina approach (n = 100) and to a cranial (n = 103) or caudal (n = 118) orientation of the bevel tip. Epidural needle placement was confirmed in 96.4% (n = 213) of cases. Nonepidural needle placement was most commonly associated with superior lamina approach and caudal bevel tip orientation, which was marginally significant (adjusted risk ratio, 6.88; 95% CI, 0.93-∞; p = 0.059). Inadvertent nonepidural needle penetration during fluoroscopically guided lumbar interlaminar ESI appears to be affected by approach, with superior lamina approach and caudal bevel tip orientation being the least favorable technique.

An automated optimization tool for high-dose-rate (HDR) prostate brachytherapy with divergent needle pattern

NASA Astrophysics Data System (ADS)

Borot de Battisti, M.; Maenhout, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; van Vulpen, M.; Moerland, M. A.

2015-10-01

Focal high-dose-rate (HDR) for prostate cancer has gained increasing interest as an alternative to whole gland therapy as it may contribute to the reduction of treatment related toxicity. For focal treatment, optimal needle guidance and placement is warranted. This can be achieved under MR guidance. However, MR-guided needle placement is currently not possible due to space restrictions in the closed MR bore. To overcome this problem, a MR-compatible, single-divergent needle-implant robotic device is under development at the University Medical Centre, Utrecht: placed between the legs of the patient inside the MR bore, this robot will tap the needle in a divergent pattern from a single rotation point into the tissue. This rotation point is just beneath the perineal skin to have access to the focal prostate tumor lesion. Currently, there is no treatment planning system commercially available which allows optimization of the dose distribution with such needle arrangement. The aim of this work is to develop an automatic inverse dose planning optimization tool for focal HDR prostate brachytherapy with needle insertions in a divergent configuration. A complete optimizer workflow is proposed which includes the determination of (1) the position of the center of rotation, (2) the needle angulations and (3) the dwell times. Unlike most currently used optimizers, no prior selection or adjustment of input parameters such as minimum or maximum dose or weight coefficients for treatment region and organs at risk is required. To test this optimizer, a planning study was performed on ten patients (treatment volumes ranged from 8.5 cm3to 23.3 cm3) by using 2-14 needle insertions. The total computation time of the optimizer workflow was below 20 min and a clinically acceptable plan was reached on average using only four needle insertions.

Poster - Thurs Eve-12: A needle-positioning robot co-registered with volumetric x-ray micro-computed tomography images for minimally-invasive small-animal interventions.

PubMed

Waspe, A C; Holdsworth, D W; Lacefield, J C; Fenster, A

2008-07-01

Preclinical research protocols often require the delivery of biological substances to specific targets in small animal disease models. To target biologically relevant locations in mice accurately, the needle positioning error needs to be < 200 μm. If targeting is inaccurate, experimental results can be inconclusive or misleading. We have developed a robotic manipulator that is capable of positioning a needle with a mean error < 100 μm. An apparatus and method were developed for integrating the needle-positioning robot with volumetric micro-computed tomography image guidance for interventions in small animals. Accurate image-to-robot registration is critical for integration as it enables targets identified in the image to be mapped to physical coordinates inside the animal. Registration is accomplished by injecting barium sulphate into needle tracks as the robot withdraws the needle from target points in a tissue-mimicking phantom. Registration accuracy is therefore affected by the positioning error of the robot and is assessed by measuring the point-to-line fiducial and target registration errors (FRE, TRE). Centroid points along cross-sectional slices of the track are determined using region growing segmentation followed by application of a center-of-mass algorithm. The centerline points are registered to needle trajectories in robot coordinates by applying an iterative closest point algorithm between points and lines. Implementing this procedure with four fiducial needle tracks produced a point-to-line FRE and TRE of 246 ± 58 μm and 194 ± 18 μm, respectively. The proposed registration technique produced a TRE < 200 μm, in the presence of robot positioning error, meeting design specification. © 2008 American Association of Physicists in Medicine.

Virtual remote center of motion control for needle placement robots.

PubMed

Boctor, Emad M; Webster, Robert J; Mathieu, Herve; Okamura, Allison M; Fichtinger, Gabor

2004-01-01

We present an algorithm that enables percutaneous needle-placement procedures to be performed with unencoded, unregistered, minimally calibrated robots while removing the constraint of placing the needle tip on a mechanically enforced Remote Center of Motion (RCM). The algorithm requires only online tracking of the surgical tool and a five-degree-of-freedom (5-DOF) robot comprising three prismatic DOF and two rotational DOF. An incremental adaptive motion control cycle guides the needle to the insertion point and also orients it to align with the target-entry-point line. The robot executes RCM motion without having a physically constrained fulcrum point. The proof-of-concept prototype system achieved 0.78 mm translation accuracy and 1.4 degrees rotational accuracy (this is within the tracker accuracy) within 17 iterative steps (0.5-1 s). This research enables robotic assistant systems for image-guided percutaneous procedures to be prototyped/constructed more quickly and less expensively than has been previously possible. Since the clinical utility of such systems is clear and has been demonstrated in the literature, our work may help promote widespread clinical adoption of this technology by lowering system cost and complexity.

Does Needle Rotation Improve Lesion Targeting?

PubMed Central

Badaan, Shadi; Petrisor, Doru; Kim, Chunwoo; Mozer, Pierre; Mazilu, Dumitru; Gruionu, Lucian; Patriciu, Alex; Cleary, Kevin; Stoianovici, Dan

2011-01-01

Background Image-guided robots are manipulators that operate based on medical images. Perhaps the most common class of image-guided robots are robots for needle interventions. Typically, these robots actively position and/or orient a needle guide, but needle insertion is still done by the physician. While this arrangement may have safety advantages and keep the physician in control of needle insertion, actuated needle drivers can incorporate other useful features. Methods We first present a new needle driver that can actively insert and rotate a needle. With this device we investigate the use of needle rotation in controlled in-vitro experiments performed with a specially developed revolving needle driver. Results These experiments show that needle rotation can improve targeting and may reduce errors by as much as 70%. Conclusion The new needle driver provides a unique kinematic architecture that enables insertion with a compact mechanism. Perhaps the most interesting conclusion of the study is that lesions of soft tissue organs may not be perfectly targeted with a needle without using special techniques, either manually or with a robotic device. The results of this study show that needle rotation may be an effective method of reducing targeting errors. PMID:21360796

Endoscopic placement of Jones lacrimal tubes with the assistance of holmium YAG laser.

PubMed

Boboridis, Kostas G; Downes, Richard N

2005-06-01

The aim of this paper is to highlight the use of the Holmium YAG laser in the endoscopic placement of Lester Jones tubes in patients with a blocked canaliculus or failed lacrimal pump function. Sixteen cases with a non-functional canaliculus were included over a one-year period. Following caruncle excision, a 19 G needle is inserted through the medial canthal tissues into the nasal space. Nasal endoscopy confirms the accurate positioning in relation to the nasal anatomy. With the Holmium YAG laser, a tissue channel is fashioned around the guide needle through the structures of the lateral nasal wall to facilitate an accurate and secure placement of the Jones tube. The endoscopic, laser-assisted placement reduces the operating time to less than 20 minutes, minimizes tissue trauma and does not require the initial surgical steps of an open DCR procedure. There were 14 cases (87.5%) with securely retained tubes and two cases (12.5%) that required tube replacement. The advantage of the procedure is especially great in revision surgery where the ostium is opened through scar tissue. Nasal endoscopy with the assistance of the Holmium YAG laser offers simplicity and precision in the placement of Jones tubes. It minimizes tissue trauma and increases the surgical success rate.

SU-D-210-07: The Dependence On Acoustic Velocity of Medium On the Needle Template and Electronic Grid Alignment in Ultrasound QA for Prostate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapoor, P; Kapoor, R; Curran, B

Purpose: To analyze the impact on acoustic velocity (AV) of two different media (water and milk) using the needle template/electronic grid alignment test. Water, easily available, makes a good material to test the alignment of the template and grid although water’s AV (1498 m/s at 25°C) is significantly different from tissue (1540 m/s). Milk, with an AV much closer (1548 m/s) to prostate tissue, may be a good substitute for water in ultrasound quality assurance testing. Methods: Tests were performed using a Hitachi ultrasound unit with a mechanical arrangement designed to position needles parallel to the transducer. In this work,more » two materials – distilled water and homogenized whole milk (AVs of 1498 and 1548 m/s at 25°C) were used in a phantom to test ultrasound needle/grid alignment. The images were obtained with both materials and analyzed for their placement accuracy. Results: The needle template/electronic grid alignment tests showed displacement errors between measured and calculated values. The measurements showed displacements of 2.3mm (water) and 0.4mm (milk), and 1.6mm (water) and 0.3mm (milk) at depths of 7cm and 5cm respectively from true needle positions. The calculated results showed a displacement of 2.36 mm (water); 0.435mm (milk), and 1.66mm (water) and 0.31mm (milk) at a depth of 7cm and 5cm respectively. The displacements in the X and Y directions were also calculated. At depths of 7cm and 5cm, the (ΔX,ΔY) displacements in water were (0.829mm, 2.21mm) and (0.273mm, 1.634mm) and for milk were (0.15mm, 0.44mm) and (0.05mm, 0.302mm) respectively. Conclusion: The measured and calculated values were in good agreement for all tests. They show that milk provides superior results when performing needle template and electronic grid alignment tests for ultrasound units used in prostate brachytherapy.« less

Flexible needle with integrated optical coherence tomography probe for imaging during transbronchial tissue aspiration

NASA Astrophysics Data System (ADS)

Li, Jiawen; Quirk, Bryden C.; Noble, Peter B.; Kirk, Rodney W.; Sampson, David D.; McLaughlin, Robert A.

2017-10-01

Transbronchial needle aspiration (TBNA) of small lesions or lymph nodes in the lung may result in nondiagnostic tissue samples. We demonstrate the integration of an optical coherence tomography (OCT) probe into a 19-gauge flexible needle for lung tissue aspiration. This probe allows simultaneous visualization and aspiration of the tissue. By eliminating the need for insertion and withdrawal of a separate imaging probe, this integrated design minimizes the risk of dislodging the needle from the lesion prior to aspiration and may facilitate more accurate placement of the needle. Results from in situ imaging in a sheep lung show clear distinction between solid tissue and two typical constituents of nondiagnostic samples (adipose and lung parenchyma). Clinical translation of this OCT-guided aspiration needle holds promise for improving the diagnostic yield of TBNA.

Litter type control on soil C and N stabilization dynamics in a temperate forest.

PubMed

Hatton, Pierre-Joseph; Castanha, Cristina; Torn, Margaret S; Bird, Jeffrey A

2015-03-01

While plant litters are the main source of soil organic matter (SOM) in forests, the controllers and pathways to stable SOM formation remain unclear. Here, we address how litter type ((13) C/(15) N-labeled needles vs. fine roots) and placement-depth (O vs. A horizon) affect in situ C and N dynamics in a temperate forest soil after 5 years. Litter type rather than placement-depth controlled soil C and N retention after 5 years in situ, with belowground fine root inputs greatly enhancing soil C (x1.4) and N (x1.2) retention compared with aboveground needles. While the proportions of added needle and fine root-derived C and N recovered into stable SOM fractions were similar, they followed different transformation pathways into stable SOM fractions: fine root transfer was slower than for needles, but proportionally more of the remaining needle-derived C and N was transferred into stable SOM fractions. The stoichiometry of litter-derived C vs. N within individual SOM fractions revealed the presence at least two pools of different turnover times (per SOM fraction) and emphasized the role of N-rich compounds for long-term persistence. Finally, a regression approach suggested that models may underestimate soil C retention from litter with fast decomposition rates. © 2014 John Wiley & Sons Ltd.

Mechanics of anesthetic needle penetration into human sciatic nerve.

PubMed

Pichamuthu, Joseph E; Maiti, Spandan; Gan, Maria G; Verdecchia, Nicole M; Orebaugh, Steven L; Vorp, David A

2018-06-06

Nerve blocks are frequently performed by anesthesiologists to control pain. For sciatic nerve blocks, the optimal placement of the needle tip between its paraneural sheath and epineurial covering is challenging, even under ultrasound guidance, and frequently results in nerve puncture. We performed needle penetration tests on cadaveric isolated paraneural sheath (IPS), isolated nerve (IN), and the nerve with overlying paraneural sheath (NPS), and quantified puncture force requirement and fracture toughness of these specimens to assess their role in determining the clinical risk of nerve puncture. We found that puncture force (123 ± 17 mN) and fracture toughness (45.48 ± 9.72 J m -2 ) of IPS was significantly lower than those for NPS (1440 ± 161 mN and 1317.46 ± 212.45 Jm -2 , respectively), suggesting that it is not possible to push the tip of the block needle through the paraneural sheath only, without pushing it into the nerve directly, when the sheath is lying directly over the nerve. Results of this study provide a physical basis for tangential placement of the needle as the ideal situation for local anesthetic deposition, as it allows for the penetration of the sheath along the edge of the nerve without entering the epineurium. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effect of toe marker placement error on joint kinematics and muscle forces using OpenSim gait simulation.

PubMed

Xu, Hang; Merryweather, Andrew; Bloswick, Donald; Mao, Qi; Wang, Tong

2015-01-01

Marker placement can be a significant source of error in biomechanical studies of human movement. The toe marker placement error is amplified by footwear since the toe marker placement on the shoe only relies on an approximation of underlying anatomical landmarks. Three total knee replacement subjects were recruited and three self-speed gait trials per subject were collected. The height variation between toe and heel markers of four types of footwear was evaluated from the results of joint kinematics and muscle forces using OpenSim. The reference condition was considered as the same vertical height of toe and heel markers. The results showed that the residual variances for joint kinematics had an approximately linear relationship with toe marker placement error for lower limb joints. Ankle dorsiflexion/plantarflexion is most sensitive to toe marker placement error. The influence of toe marker placement error is generally larger for hip flexion/extension and rotation than hip abduction/adduction and knee flexion/extension. The muscle forces responded to the residual variance of joint kinematics to various degrees based on the muscle function for specific joint kinematics. This study demonstrates the importance of evaluating marker error for joint kinematics and muscle forces when explaining relative clinical gait analysis and treatment intervention.

Automatic Correction of Adverb Placement Errors for CALL

ERIC Educational Resources Information Center

Garnier, Marie

2012-01-01

According to recent studies, there is a persistence of adverb placement errors in the written productions of francophone learners and users of English at an intermediate to advanced level. In this paper, we present strategies for the automatic detection and correction of errors in the placement of manner adverbs, using linguistic-based natural…

Predictors of pneumothorax after CT-guided transthoracic needle lung biopsy: the role of quantitative CT.

PubMed

Chami, H A; Faraj, W; Yehia, Z A; Badour, S A; Sawan, P; Rebeiz, K; Safa, R; Saade, C; Ghandour, B; Shamseddine, A; Mukherji, D; Haydar, A A

2015-12-01

To evaluate the association of quantitative computed tomography (CT) measures of emphysema with the occurrence of pneumothorax after CT-guided needle lung biopsy (NLB) accounting for other risk factors. One hundred and sixty-three CT-guided NLBs performed between 2008 and 2013 with available complete chest CT within 30 days were reviewed for the occurrence of post-procedure pneumothorax. Percent emphysema was determined quantitatively as the percentage of lung voxels below -950 HU on chest CT images using automated software. Multivariable regression was used to assess the association of percent emphysema volume with the occurrence of post-procedure pneumothorax. The association of percent emphysema volume with the pneumothorax size and need for chest tube placement after NLB was also explored. Percent emphysema was significantly associated with the incidence of post-NLB pneumothorax (OR=1.10 95% confidence interval: 1.01-1.15; p=0.03) adjusting for lower-lobe lesion location, needle path length, lesion size, number of passes, and pleural needle trajectory angle. Percent emphysema was not associated with the size of the pneumothorax, nor the need for chest tube placement after NLB. Percent emphysema determined quantitatively from chest CT is a significant predictor of post-NLB pneumothorax. Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

The epidural needle guidance with an intelligent and automatic identification system for epidural anesthesia

NASA Astrophysics Data System (ADS)

Kao, Meng-Chun; Ting, Chien-Kun; Kuo, Wen-Chuan

2018-02-01

Incorrect placement of the needle causes medical complications in the epidural block, such as dural puncture or spinal cord injury. This study proposes a system which combines an optical coherence tomography (OCT) imaging probe with an automatic identification (AI) system to objectively identify the position of the epidural needle tip. The automatic identification system uses three features as image parameters to distinguish the different tissue by three classifiers. Finally, we found that the support vector machine (SVM) classifier has highest accuracy, specificity, and sensitivity, which reached to 95%, 98%, and 92%, respectively.

The Accuracy of a Handheld Ultrasound Device for Neuraxial Depth and Landmark Assessment: A Prospective Cohort Trial.

PubMed

Seligman, Katherine M; Weiniger, Carolyn F; Carvalho, Brendan

2017-08-30

This study investigated the accuracy of a wireless handheld ultrasound with pattern recognition software that recognizes lumbar spine bony landmarks and measures depth to epidural space (Accuro, Rivanna Medical, Charlottesville, VA) (AU). AU measurements to epidural space were compared to Tuohy needle depth to epidural space (depth to loss of resistance at epidural placement). Data from 47 women requesting labor epidural analgesia were analyzed. The mean difference between depth to epidural space measured by AU versus needle depth was -0.61 cm (95% confidence interval, -0.79 to -0.44), with a standard deviation of 0.58 (95% confidence interval, 0.48-0.73). Using the AU-identified insertion point resulted in successful epidural placement at first attempt in 87% of patients, 78% without redirects.

CT guided interstitial therapy of pancreatic carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haaga, J.R.; Owens, D.B.; Kellermeyer, R.W.

1987-11-01

We describe the use of percutaneous CT guidance for localization and placement of /sup 192/Ir sources into a patient with pancreatic carcinoma. We have shown the feasibility of this procedure and the lack of complications which are probably due to minimal damage to tissue involved. Computed tomography is ideally suited for percutaneous implantation because it provides the most accurate method for needle placement within the abdomen.

MRI-Compatible Pneumatic Robot for Transperineal Prostate Needle Placement.

PubMed

Fischer, Gregory S; Iordachita, Iulian; Csoma, Csaba; Tokuda, Junichi; Dimaio, Simon P; Tempany, Clare M; Hata, Nobuhiko; Fichtinger, Gabor

2008-06-01

Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of prostate and surrounding tissue, thus granting potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. However, the benefits cannot be readily harnessed for interventional procedures due to difficulties that surround the use of high-field (1.5T or greater) MRI. The inability to use conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intraprostatic needle placement inside closed high-field MRI scanners. MRI compatibility of the robot has been evaluated under 3T MRI using standard prostate imaging sequences and average SNR loss is limited to 5%. Needle alignment accuracy of the robot under servo pneumatic control is better than 0.94 mm rms per axis. The complete system workflow has been evaluated in phantom studies with accurate visualization and targeting of five out of five 1 cm targets. The paper explains the robot mechanism and controller design, the system integration, and presents results of preliminary evaluation of the system.

Coaxial needle insertion assistant with enhanced force feedback.

PubMed

De Lorenzo, Danilo; Koseki, Yoshihiko; De Momi, Elena; Chinzei, Kiyoyuki; Okamura, Allison M

2013-02-01

Many medical procedures involving needle insertion into soft tissues, such as anesthesia, biopsy, brachytherapy, and placement of electrodes, are performed without image guidance. In such procedures, haptic detection of changing tissue properties at different depths during needle insertion is important for needle localization and detection of subsurface structures. However, changes in tissue mechanical properties deep inside the tissue are difficult for human operators to sense, because the relatively large friction force between the needle shaft and the surrounding tissue masks the smaller tip forces. A novel robotic coaxial needle insertion assistant, which enhances operator force perception, is presented. This one-degree-of-freedom cable-driven robot provides to the operator a scaled version of the force applied by the needle tip to the tissue, using a novel design and sensors that separate the needle tip force from the shaft friction force. The ability of human operators to use the robot to detect membranes embedded in artificial soft tissue was tested under the conditions of 1) tip force and shaft force feedback, and 2) tip force only feedback. The ratio of successful to unsuccessful membrane detections was significantly higher (up to 50%) when only the needle tip force was provided to the user.

An Accurate Full-flexion Anterolateral Portal for Needle Placement in the Knee Joint With Dry Osteoarthritis.

PubMed

Hussein, Mohamed

2017-07-01

Accurate delivery of an injection into the intra-articular space of the knee is achieved in only two thirds of knees when using the standard anterolateral portal. The use of a modified full-flexion anterolateral portal provides a highly accurate, less painful, and more effective method for reproducible intra-articular injection without the need for ultrasonographic or fluoroscopic guidance in patients with dry osteoarthritis of the knee. The accuracy of needle placement was assessed in a prospective series of 140 consecutive injections in patients with symptomatic degenerative knee arthritis without clinical knee effusion. Procedural pain was determined using the Numerical Rating Scale. The accuracy rates of needle placement were confirmed with fluoroscopic imaging to document the dispersion pattern of injected contrast material. Using the standard anterolateral portal, 52 of 70 injections were confirmed to have been placed in the intra-articular space on the first attempt (accuracy rate, 74.2%). Using the modified full-flexion anterolateral portal, 68 of 70 injections were placed in the intra-articular space on the first attempt (accuracy rate, 97.1%; P = 0.000). This study revealed that using the modified full-flexion anterolateral portal for injections into the knee joint resulted in more accurate and less painful injections than those performed by the same orthopaedic surgeon using the standard anterolateral portal. In addition, the technique offered therapeutic delivery into the joint without the need for fluoroscopic confirmation. Therapeutic Level II.

Sensorimotor Learning of Acupuncture Needle Manipulation Using Visual Feedback

PubMed Central

Jung, Won-Mo; Lim, Jinwoong; Lee, In-Seon; Park, Hi-Joon; Wallraven, Christian; Chae, Younbyoung

2015-01-01

Objective Humans can acquire a wide variety of motor skills using sensory feedback pertaining to discrepancies between intended and actual movements. Acupuncture needle manipulation involves sophisticated hand movements and represents a fundamental skill for acupuncturists. We investigated whether untrained students could improve their motor performance during acupuncture needle manipulation using visual feedback (VF). Methods Twenty-one untrained medical students were included, randomly divided into concurrent (n = 10) and post-trial (n = 11) VF groups. Both groups were trained in simple lift/thrusting techniques during session 1, and in complicated lift/thrusting techniques in session 2 (eight training trials per session). We compared the motion patterns and error magnitudes of pre- and post-training tests. Results During motion pattern analysis, both the concurrent and post-trial VF groups exhibited greater improvements in motion patterns during the complicated lifting/thrusting session. In the magnitude error analysis, both groups also exhibited reduced error magnitudes during the simple lifting/thrusting session. For the training period, the concurrent VF group exhibited reduced error magnitudes across all training trials, whereas the post-trial VF group was characterized by greater error magnitudes during initial trials, which gradually reduced during later trials. Conclusions Our findings suggest that novices can improve the sophisticated hand movements required for acupuncture needle manipulation using sensorimotor learning with VF. Use of two types of VF can be beneficial for untrained students in terms of learning how to manipulate acupuncture needles, using either automatic or cognitive processes. PMID:26406248

Semicircular thermocouple needle depth gauge for cryoprocedures.

PubMed

Pappenfort, R B

1981-06-01

A semicircular thermocouple needle depth gauge made of an aluminum alloy drilled with tracks at different angles to place thermocouple needles at various depths below the surface is described herein. Its shape offers definite advantages over circular jigs (templates) when doing cryoexperimentation and when used clinically. The material of which it is made is more durable than plastic. Grommets that firmly snap in place within the inner rim of the instrument permit accurate placement of liquid gas spray, cryoprobes, and other applicators directly over the thermocouple needle tips. This is of special importance when doing cryoexperiments. Furthermore, with this design, the advancing ice front and possible liquid gas runoff are more easily seen. By using both halves it is suitable for monitoring the temperature when freezing large tumors at two different sites and a different depths.

Transillumination for needle localization in the larynx.

PubMed

Hoffman, Henry T; Dailey, Seth H; Bock, Jonathan M; Thibeault, Susan L; McCulloch, Timothy M

2015-10-01

Transillumination through laryngeal soft tissue may be used to direct percutaneous transcricothyroid membrane subepithelial needle placement in the larynx. Cadaver simulation (canine and human). Lighted devices, including sialendoscopes and fiberoptic cables, were tested as transilluminating obturators in trocars and needles through multiple studies to identify appropriate illumination, monitoring, and equipment for successful localization of needle/trocar tips placed within laryngeal tissue. Lighted 250-micron fiberoptic cables within 23-gauge needles were successfully placed percutaneously through the cricothyroid membrane and maneuvered submucosally into Reinke's space, the midlateral vocal fold, and through the thyroarytenoid gap with monitoring via flexible transnasal laryngoscopy. Technical adaptations in the course of study permitted successful simulation of clinical use in full cadaver study for accurate injection laryngoplasty, confirmed by laryngeal dissection following collagen injection. Small caliber fiberoptic cables are useful as transilluminating obturators to accurately direct needle position within laryngeal tissue. Clinical application of this new technique is anticipated to improve the accuracy of percutaneous needle localization in the larynx, as well as to assist in directed instrumentation of the larynx from an external approach. N/A. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Intra-operative navigation of a 3-dimensional needle localization system for precision of irreversible electroporation needles in locally advanced pancreatic cancer.

PubMed

Bond, L; Schulz, B; VanMeter, T; Martin, R C G

2017-02-01

Irreversible electroporation (IRE) uses multiple needles and a series of electrical pulses to create pores in cell membranes and cause cell apoptosis. One of the demands of IRE is the precise needle spacing required. Two-dimensional intraoperative ultrasound (2-D iUS) is currently used to measure inter-needle distances but requires significant expertise. This study evaluates the potential of three-dimensional (3-D) image guidance for placing IRE needles and calculating needle spacing. A prospective clinical evaluation of a 3-D needle localization system (Explorer™) was evaluated in consecutive patients from April 2012 through June 2013 for unresectable pancreatic adenocarcinoma. 3-D reconstructions of patients' anatomy were generated from preoperative CT images, which were aligned to the intraoperative space. Thirty consecutive patients with locally advanced pancreatic cancer were treated with IRE. The needle localization system setup added an average of 6.5 min to each procedure. The 3-D needle localization system increased surgeon confidence and ultimately reduced needle placement time. IRE treatment efficacy is highly dependent on accurate needle spacing. The needle localization system evaluated in this study aims to mitigate these issues by providing the surgeon with additional visualization and data in 3-D. The Explorer™ system provides valuable guidance information and inter-needle distance calculations. Copyright © 2016 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

Comparison of Spinal Needle Deflection in a Ballistic Gel Model.

PubMed

Rand, Ethan; Christolias, George; Visco, Christopher; R Singh, Jaspal

2016-10-01

Percutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape. The purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant. Six needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle. In comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal. There is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial.

Comparison of Spinal Needle Deflection in a Ballistic Gel Model

PubMed Central

Rand, Ethan; Christolias, George; Visco, Christopher; R. Singh, Jaspal

2016-01-01

Background Percutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape. Objectives The purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant. Materials and Methods Six needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle. Results In comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal. Conclusions There is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial. PMID:27847693

Cadaveric and Ultrasonographic Validation of Needling Placement in the Cervical Multifidus Muscle.

PubMed

Fernández-de-Las-Peñas, César; Mesa-Jiménez, Juan A; Paredes-Mancilla, Jose A; Koppenhaver, Shane L; Fernández-Carnero, Samuel

2017-06-01

The aim of this study was to determine if a needle is able to reach the cervical multifidus during the application of dry needling or acupuncture. Dry needling and ultrasound imaging of cervical multifidi was conducted on 5 patients (age: 32 ± 5 years) with mechanical neck pain and on 2 fresh cadavers (age: 64 ± 1 years). Dry needling was done using a needle of 40 mm in length inserted perpendicular to the skin about 1 cm lateral to the spinous process at C3-C4. The needle was advanced from a posterior to anterior direction into the cervical multifidus with a slight inferior-medial angle (approximately 10°) to reach the vertebra lamina. For the cadaveric study, the multifidus was isolated by carefully resecting the superficial posterior cervical muscles: trapezius, splenius, and semispinalis. For the ultrasonographic study, a convex transducer was placed transversely over C3-C4 after the insertion of the needle into the muscle. The results of both the cadaveric and ultrasonic studies found that the needle does pierce the cervical multifidus muscle during insertion and that the tip of the needle rests properly against the vertebral laminae, thereby guarding the sensitive underlying spinal structures from damage. This anatomical and ultrasound imaging study supports that dry needling of the cervical multifidus could be conducted clinically. Copyright © 2017. Published by Elsevier Inc.

MRI-Compatible Pneumatic Robot for Transperineal Prostate Needle Placement

PubMed Central

Fischer, Gregory S.; Iordachita, Iulian; Csoma, Csaba; Tokuda, Junichi; DiMaio, Simon P.; Tempany, Clare M.; Hata, Nobuhiko; Fichtinger, Gabor

2010-01-01

Magnetic resonance imaging (MRI) can provide high-quality 3-D visualization of prostate and surrounding tissue, thus granting potential to be a superior medical imaging modality for guiding and monitoring prostatic interventions. However, the benefits cannot be readily harnessed for interventional procedures due to difficulties that surround the use of high-field (1.5T or greater) MRI. The inability to use conventional mechatronics and the confined physical space makes it extremely challenging to access the patient. We have designed a robotic assistant system that overcomes these difficulties and promises safe and reliable intraprostatic needle placement inside closed high-field MRI scanners. MRI compatibility of the robot has been evaluated under 3T MRI using standard prostate imaging sequences and average SNR loss is limited to 5%. Needle alignment accuracy of the robot under servo pneumatic control is better than 0.94 mm rms per axis. The complete system workflow has been evaluated in phantom studies with accurate visualization and targeting of five out of five 1 cm targets. The paper explains the robot mechanism and controller design, the system integration, and presents results of preliminary evaluation of the system. PMID:21057608

Controlling the error on target motion through real-time mesh adaptation: Applications to deep brain stimulation.

PubMed

Bui, Huu Phuoc; Tomar, Satyendra; Courtecuisse, Hadrien; Audette, Michel; Cotin, Stéphane; Bordas, Stéphane P A

2018-05-01

An error-controlled mesh refinement procedure for needle insertion simulations is presented. As an example, the procedure is applied for simulations of electrode implantation for deep brain stimulation. We take into account the brain shift phenomena occurring when a craniotomy is performed. We observe that the error in the computation of the displacement and stress fields is localised around the needle tip and the needle shaft during needle insertion simulation. By suitably and adaptively refining the mesh in this region, our approach enables to control, and thus to reduce, the error whilst maintaining a coarser mesh in other parts of the domain. Through academic and practical examples we demonstrate that our adaptive approach, as compared with a uniform coarse mesh, increases the accuracy of the displacement and stress fields around the needle shaft and, while for a given accuracy, saves computational time with respect to a uniform finer mesh. This facilitates real-time simulations. The proposed methodology has direct implications in increasing the accuracy, and controlling the computational expense of the simulation of percutaneous procedures such as biopsy, brachytherapy, regional anaesthesia, or cryotherapy. Moreover, the proposed approach can be helpful in the development of robotic surgeries because the simulation taking place in the control loop of a robot needs to be accurate, and to occur in real time. Copyright © 2018 John Wiley & Sons, Ltd.

Creating and evaluating a data-driven curriculum for central venous catheter placement.

PubMed

Duncan, James R; Henderson, Katherine; Street, Mandie; Richmond, Amy; Klingensmith, Mary; Beta, Elio; Vannucci, Andrea; Murray, David

2010-09-01

Central venous catheter placement is a common procedure with a high incidence of error. Other fields requiring high reliability have used Failure Mode and Effects Analysis (FMEA) to prioritize quality and safety improvement efforts. To use FMEA in the development of a formal, standardized curriculum for central venous catheter training. We surveyed interns regarding their prior experience with central venous catheter placement. A multidisciplinary team used FMEA to identify high-priority failure modes and to develop online and hands-on training modules to decrease the frequency, diminish the severity, and improve the early detection of these failure modes. We required new interns to complete the modules and tracked their progress using multiple assessments. Survey results showed new interns had little prior experience with central venous catheter placement. Using FMEA, we created a curriculum that focused on planning and execution skills and identified 3 priority topics: (1) retained guidewires, which led to training on handling catheters and guidewires; (2) improved needle access, which prompted the development of an ultrasound training module; and (3) catheter-associated bloodstream infections, which were addressed through training on maximum sterile barriers. Each module included assessments that measured progress toward recognition and avoidance of common failure modes. Since introducing this curriculum, the number of retained guidewires has fallen more than 4-fold. Rates of catheter-associated infections have not yet declined, and it will take time before ultrasound training will have a measurable effect. The FMEA provided a process for curriculum development. Precise definitions of failure modes for retained guidewires facilitated development of a curriculum that contributed to a dramatic decrease in the frequency of this complication. Although infections and access complications have not yet declined, failure mode identification, curriculum development, and monitored implementation show substantial promise for improving patient safety during placement of central venous catheters.

Probabilistic registration of an unbiased statistical shape model to ultrasound images of the spine

NASA Astrophysics Data System (ADS)

Rasoulian, Abtin; Rohling, Robert N.; Abolmaesumi, Purang

2012-02-01

The placement of an epidural needle is among the most difficult regional anesthetic techniques. Ultrasound has been proposed to improve success of placement. However, it has not become the standard-of-care because of limitations in the depictions and interpretation of the key anatomical features. We propose to augment the ultrasound images with a registered statistical shape model of the spine to aid interpretation. The model is created with a novel deformable group-wise registration method which utilizes a probabilistic approach to register groups of point sets. The method is compared to a volume-based model building technique and it demonstrates better generalization and compactness. We instantiate and register the shape model to a spine surface probability map extracted from the ultrasound images. Validation is performed on human subjects. The achieved registration accuracy (2-4 mm) is sufficient to guide the choice of puncture site and trajectory of an epidural needle.

SU-F-T-320: Assessing Placement Error of Optically Stimulated Luminescent in Vivo Dosimeters Using Cone-Beam Computed Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riegel, A; Klein, E; Tariq, M

Purpose: Optically-stimulated luminescent dosimeters (OSLDs) are increasingly utilized for in vivo dosimetry of complex radiation delivery techniques such as intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Evaluation of clinical uncertainties such as placement error has not been performed. This work retrospectively investigates the magnitude of placement error using conebeam computed tomography (CBCT) and its effect on measured/planned dose agreement. Methods: Each OSLD was placed at a physicist-designated location on the patient surface on a weekly basis. The location was given in terms of a gantry angle and two-dimensional offset from central axis. The OSLDs were placed before dailymore » image guidance. We identified 77 CBCTs from 25 head-and-neck patients who received IMRT or VMAT, where OSLDs were visible on the CT image. Grossly misplaced OSLDs were excluded (e.g. wrong laterality). CBCTs were registered with the treatment plan and the distance between the planned and actual OSLD location was calculated in two dimensions in the beam’s eye view. Distances were correlated with measured/planned dose percent differences. Results: OSLDs were grossly misplaced for 5 CBCTs (6.4%). For the remaining 72 CBCTs, average placement error was 7.0±6.0 mm. These errors were not correlated with measured/planned dose percent differences (R{sup 2}=0.0153). Generalizing the dosimetric effect of placement errors may be unreliable. Conclusion: Correct placement of OSLDs for IMRT and VMAT treatments is critical to accurate and precise in vivo dosimetry. Small placement errors could produce large disagreement between measured and planned dose. Further work includes expansion to other treatment sites, examination of planned dose at the actual point of OSLD placement, and the influence of imageguided shifts on measured/planned dose agreement.« less

Objective assessment of operator performance during ultrasound-guided procedures.

PubMed

Tabriz, David M; Street, Mandie; Pilgram, Thomas K; Duncan, James R

2011-09-01

Simulation permits objective assessment of operator performance in a controlled and safe environment. Image-guided procedures often require accurate needle placement, and we designed a system to monitor how ultrasound guidance is used to monitor needle advancement toward a target. The results were correlated with other estimates of operator skill. The simulator consisted of a tissue phantom, ultrasound unit, and electromagnetic tracking system. Operators were asked to guide a needle toward a visible point target. Performance was video-recorded and synchronized with the electromagnetic tracking data. A series of algorithms based on motor control theory and human information processing were used to convert raw tracking data into different performance indices. Scoring algorithms converted the tracking data into efficiency, quality, task difficulty, and targeting scores that were aggregated to create performance indices. After initial feasibility testing, a standardized assessment was developed. Operators (N = 12) with a broad spectrum of skill and experience were enrolled and tested. Overall scores were based on performance during ten simulated procedures. Prior clinical experience was used to independently estimate operator skill. When summed, the performance indices correlated well with estimated skill. Operators with minimal or no prior experience scored markedly lower than experienced operators. The overall score tended to increase according to operator's clinical experience. Operator experience was linked to decreased variation in multiple aspects of performance. The aggregated results of multiple trials provided the best correlation between estimated skill and performance. A metric for the operator's ability to maintain the needle aimed at the target discriminated between operators with different levels of experience. This study used a highly focused task model, standardized assessment, and objective data analysis to assess performance during simulated ultrasound-guided needle placement. The performance indices were closely related to operator experience.

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions.

PubMed

Waspe, Adam C; McErlain, David D; Pitelka, Vasek; Holdsworth, David W; Lacefield, James C; Fenster, Aaron

2010-04-01

Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting a barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 microm tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 microm, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154 +/- 113 microm. The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.

Integration and evaluation of a needle-positioning robot with volumetric microcomputed tomography image guidance for small animal stereotactic interventions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waspe, Adam C.; McErlain, David D.; Pitelka, Vasek

Purpose: Preclinical research protocols often require insertion of needles to specific targets within small animal brains. To target biologically relevant locations in rodent brains more effectively, a robotic device has been developed that is capable of positioning a needle along oblique trajectories through a single burr hole in the skull under volumetric microcomputed tomography (micro-CT) guidance. Methods: An x-ray compatible stereotactic frame secures the head throughout the procedure using a bite bar, nose clamp, and ear bars. CT-to-robot registration enables structures identified in the image to be mapped to physical coordinates in the brain. Registration is accomplished by injecting amore » barium sulfate contrast agent as the robot withdraws the needle from predefined points in a phantom. Registration accuracy is affected by the robot-positioning error and is assessed by measuring the surface registration error for the fiducial and target needle tracks (FRE and TRE). This system was demonstrated in situ by injecting 200 {mu}m tungsten beads into rat brains along oblique trajectories through a single burr hole on the top of the skull under micro-CT image guidance. Postintervention micro-CT images of each skull were registered with preintervention high-field magnetic resonance images of the brain to infer the anatomical locations of the beads. Results: Registration using four fiducial needle tracks and one target track produced a FRE and a TRE of 96 and 210 {mu}m, respectively. Evaluation with tissue-mimicking gelatin phantoms showed that locations could be targeted with a mean error of 154{+-}113 {mu}m. Conclusions: The integration of a robotic needle-positioning device with volumetric micro-CT image guidance should increase the accuracy and reduce the invasiveness of stereotactic needle interventions in small animals.« less

Development of 3D ultrasound needle guidance for high-dose-rate interstitial brachytherapy of gynaecological cancers

NASA Astrophysics Data System (ADS)

Rodgers, J.; Tessier, D.; D'Souza, D.; Leung, E.; Hajdok, G.; Fenster, A.

2016-04-01

High-dose-rate (HDR) interstitial brachytherapy is often included in standard-of-care for gynaecological cancers. Needles are currently inserted through a perineal template without any standard real-time imaging modality to assist needle guidance, causing physicians to rely on pre-operative imaging, clinical examination, and experience. While two-dimensional (2D) ultrasound (US) is sometimes used for real-time guidance, visualization of needle placement and depth is difficult and subject to variability and inaccuracy in 2D images. The close proximity to critical organs, in particular the rectum and bladder, can lead to serious complications. We have developed a three-dimensional (3D) transrectal US system and are investigating its use for intra-operative visualization of needle positions used in HDR gynaecological brachytherapy. As a proof-of-concept, four patients were imaged with post-insertion 3D US and x-ray CT. Using software developed in our laboratory, manual rigid registration of the two modalities was performed based on the perineal template's vaginal cylinder. The needle tip and a second point along the needle path were identified for each needle visible in US. The difference between modalities in the needle trajectory and needle tip position was calculated for each identified needle. For the 60 needles placed, the mean trajectory difference was 3.23 +/- 1.65° across the 53 visible needle paths and the mean difference in needle tip position was 3.89 +/- 1.92 mm across the 48 visible needles tips. Based on the preliminary results, 3D transrectal US shows potential for the development of a 3D US-based needle guidance system for interstitial gynaecological brachytherapy.

Experimental platform for intra-uterine needle placement procedures

NASA Astrophysics Data System (ADS)

Madjidi, Yashar; Haidegger, Tamás.; Ptacek, Wolfgang; Berger, Daniel; Kirisits, Christian; Kronreif, Gernot; Fichtinger, Gabor

2013-03-01

A framework has been investigated to enable a variety of comparative studies in the context of needle-based gynaecological brachytherapy. Our aim was to create an anthropomorphic phantom-based platform. The three main elements of the platform are the organ model, needle guide, and needle drive. These have been studied and designed to replicate the close environment of brachytherapy treatment for cervical cancer. Key features were created with the help of collaborating interventional radio-oncologists and the observations made in the operating room. A phantom box, representing the uterus model, has been developed considering available surgical analogies and operational limitations, such as organs at risk. A modular phantom-based platform has been designed and prototyped with the capability of providing various boundary conditions for the target organ. By mimicking the female pelvic floor, this framework has been used to compare a variety of needle insertion techniques and configurations for cervical and uterine interventions. The results showed that the proposed methodology is useful for the investigation of quantifiable experiments in the intraabdominal and pelvic regions.

Embracing Errors in Simulation-Based Training: The Effect of Error Training on Retention and Transfer of Central Venous Catheter Skills.

PubMed

Gardner, Aimee K; Abdelfattah, Kareem; Wiersch, John; Ahmed, Rami A; Willis, Ross E

2015-01-01

Error management training is an approach that encourages exposure to errors during initial skill acquisition so that learners can be equipped with important error identification, management, and metacognitive skills. The purpose of this study was to determine how an error-focused training program affected performance, retention, and transfer of central venous catheter (CVC) placement skills when compared with traditional training methodologies. Surgical interns (N = 30) participated in a 1-hour session featuring an instructional video and practice performing internal jugular (IJ) and subclavian (SC) CVC placement with guided instruction. All interns underwent baseline knowledge and skill assessment for IJ and SC (pretest) CVC placement; watched a "correct-only" (CO) or "correct + error" (CE) instructional video; practiced for 30 minutes; and were posttested on knowledge and IJ and SC CVC placement. Skill retention and transfer (femoral CVC placement) were assessed 30 days later. All skills tests (pretest, posttest, and transfer) were videorecorded and deidentified for evaluation by a single blinded instructor using a validated 17-item checklist. Both the groups exhibited significant improvements (p < 0.001) in knowledge and skills after the 1-hour training program, but the increase of items achieved on the performance checklist did not differ between conditions (CO: IJ Δ = 35%, SC Δ = 29%; CE: IJ Δ = 36%, subclavian Δ = 33%). However, 1 month later, the CO group exhibited significant declines in skill retention on IJ CVC placement (from 68% at posttraining to 44% at day 30; p < 0.05) and SC CVC placement (from 63% at posttraining to 49% at day 30; p < 0.05), whereas the CE group did not have significant decreases in performance. The CE group performed significantly better on femoral CVC placement (i.e., transfer task; 62% vs 38%; p < 0.01) and on 2 of the 3 complication scenarios (p < 0.05) when compared with the CO group. These data indicate that incorporating error-based activities and discussions into training programs can be beneficial for skill retention and transfer. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Methods for prostate stabilization during transperineal LDR brachytherapy.

PubMed

Podder, Tarun; Sherman, Jason; Rubens, Deborah; Messing, Edward; Strang, John; Ng, Wan-Sing; Yu, Yan

2008-03-21

In traditional prostate brachytherapy procedures for a low-dose-rate (LDR) radiation seed implant, stabilizing needles are first inserted to provide some rigidity and support to the prostate. Ideally this will provide better seed placement and an overall improved treatment. However, there is much speculation regarding the effectiveness of using regular brachytherapy needles as stabilizers. In this study, we explored the efficacy of two types of needle geometries (regular brachytherapy needle and hooked needle) and several clinically feasible configurations of the stabilization needles. To understand and assess the prostate movement during seed implantation, we collected in vivo data from patients during actual brachytherapy procedures. In vitro experimentation with tissue-equivalent phantoms allowed us to further understand the mechanics behind prostate stabilization. We observed superior stabilization with the hooked needles compared to the regular brachytherapy needles (more than 40% in bilateral parallel needle configuration). Prostate movement was also reduced significantly when regular brachytherapy needles were in an angulated configuration as compared to the parallel configuration (more than 60%). When the hooked needles were angulated for stabilization, further reduction in prostate displacement was observed. In general, for convenience of dosimetric planning and to avoid needle collision, all needles are desired to be in a parallel configuration. In this configuration, hooked needles provide improved stabilization of the prostate. On the other hand, both regular and hooked needles appear to be equally effective in reducing prostate movement when they are in angulated configurations, which will be useful in seed implantation using a robotic system. We have developed nonlinear spring-damper model for the prostate movement which can be used for adapting dosimetric planning during brachytherapy as well as for developing more realistic haptic devices and training simulators.

Special Section: Complementary and Alternative Medicine (CAM): Acupuncture From Ancient Practice to Modern Science

MedlinePlus

... Home Current Issue Past Issues Special Section CAM Acupuncture From Ancient Practice to Modern Science Past Issues / ... percent of U.S. adults use acupuncture. What Is Acupuncture? Dr. Adeline Ge adjusts placement of acupuncture needles ...

Evaluation of electrical nerve stimulation for epidural catheter positioning in the dog.

PubMed

Garcia-Pereira, Fernando L; Sanders, Robert; Shih, Andre C; Sonea, Ioana M; Hauptman, Joseph G

2013-09-01

To evaluate the accuracy of epidural catheter placement at different levels of the spinal cord guided solely by electrical nerve stimulation and resultant segmental muscle contraction. Prospective, experiment. Six male and two female Beagles, age (1 ± 0.17 years) and weight (12.9 ± 1.1 kg). Animals were anesthetized with propofol and maintained with isoflurane. An insulated epidural needle was used to reach the lumbosacral epidural space. A Tsui epidural catheter was inserted and connected to a nerve stimulator (1.0 mA, 0.1 ms, 2 Hz) to assess positioning of the tip at specific spinal cord segments. The catheter was advanced to three different levels of the spinal cord: lumbar (L2-L5), thoracic (T5-T10) and cervical (C4-C6). Subcutaneous needles were previously placed at these spinal levels and the catheter was advanced to match the needle location, guided only by corresponding muscle contractions. Catheter position was verified by fluoroscopy. If catheter tip and needle were at the same vertebral body a score of zero was assigned. When catheter tip was cranial or caudal to the needle, positive or negative numbers, respectively, corresponding to the number of vertebrae between them, were assigned. The mean and standard deviation of the number of vertebrae between catheter tip and needle were calculated to assess accuracy. Results are given as mean ± SD. The catheter position in relation to the needle was within 0.3 ± 2.0 vertebral bodies. Positive predictive values (PPV) were 57%, 83% and 71% for lumbar, thoracic and cervical regions respectively. Overall PPV was 70%. No significant difference in PPV among regions was found. Placement of an epidural catheter at specific spinal levels using electrical nerve stimulation was feasible without radiographic assistance in dogs. Two vertebral bodies difference from the target site may be clinically acceptable when performing segmental epidural regional anesthesia. © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Nonpalpable breast tumors: diagnosis with stereotaxic localization and fine-needle aspiration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dowlatshahi, K.; Gent, H.J.; Schmidt, R.

1989-02-01

Modern mammography is the most effective means of detecting nonpalpable breast cancers, but correct diagnosis for malignancy is made in only 20%-30% of the cases. The conventional method of lesion localization usually results in approximate placement of the hookwire in the breast. The authors report the results of stereotaxic localization, combined with fine-needle aspiration and cytologic study, performed in 528 cases. Clinically occult breast lesions were localized precisely (within 2 mm 96% of the time), sampled by means of a 23-gauge needle, and marked with either methylene blue or a hookwire for subsequent open excisional biopsy. The results indicate amore » sensitivity of 95%, specificity of 91%, and accuracy of 92% for the fine-needle aspiration procedure. This technique offers a significantly improved preoperative method of diagnosing small breast lesions with minimal pain, no complications, reduced cost, and no disfigurement or scar interfering with subsequent mammographic follow-up.« less

[Radiofrequency ablation of hepatocellular carcinoma].

PubMed

Widmann, Gerlig; Schullian, Peter; Bale, Reto

2013-03-01

Percutaneous radiofrequency ablation (RFA) is well established in the treatment of hepatocellular carcinoma (HCC). Due to its curative potential, it is the method of choice for non resectable BCLC (Barcelona Liver Clinic) 0 and A. RFA challenges surgical resection for small HCC and is the method of choice in bridging for transplantation and recurrence after resection or transplantation. The technical feasibility of RFA depends on the size and location of the HCC and the availability of ablation techniques (one needle techniques, multi-needle techniques). More recently, stereotactic multi-needle techniques with 3D trajectory planning and guided needle placement substantially improve the spectrum of treatable lesions including large volume tumors. Treatment success depends on the realization of ablations with large intentional margins of tumor free tissue (A0 ablation in analogy to R0 resection), which has to be documented by fusion of post- with pre-ablation images, and confirmed during follow-up imaging.

Simplified stereo-optical ultrasound plane calibration

NASA Astrophysics Data System (ADS)

Hoßbach, Martin; Noll, Matthias; Wesarg, Stefan

2013-03-01

Image guided therapy is a natural concept and commonly used in medicine. In anesthesia, a common task is the injection of an anesthetic close to a nerve under freehand ultrasound guidance. Several guidance systems exist using electromagnetic tracking of the ultrasound probe as well as the needle, providing the physician with a precise projection of the needle into the ultrasound image. This, however, requires additional expensive devices. We suggest using optical tracking with miniature cameras attached to a 2D ultrasound probe to achieve a higher acceptance among physicians. The purpose of this paper is to present an intuitive method to calibrate freehand ultrasound needle guidance systems employing a rigid stereo camera system. State of the art methods are based on a complex series of error prone coordinate system transformations which makes them susceptible to error accumulation. By reducing the amount of calibration steps to a single calibration procedure we provide a calibration method that is equivalent, yet not prone to error accumulation. It requires a linear calibration object and is validated on three datasets utilizing di erent calibration objects: a 6mm metal bar and a 1:25mm biopsy needle were used for experiments. Compared to existing calibration methods for freehand ultrasound needle guidance systems, we are able to achieve higher accuracy results while additionally reducing the overall calibration complexity. Ke

[Possibility of cauda equina nerve root damage from lumbar punctures performed with 25-gauge Quincke and Whitacre needles].

PubMed

Reina, M A; López, A; Villanueva, M C; De Andrés, J A; Martín, S

2005-05-01

To assess the possibility of puncturing nerve roots in the cauda equina with spinal needles with different point designs and to quantify the number of axons affected. We performed in vitro punctures of human nerve roots taken from 3 fresh cadavers. Twenty punctures were performed with 25-gauge Whitacre needles and 40 with 25-gauge Quincke needles; half the Quincke needle punctures were carried out with the point perpendicular to the root and the other half with the point parallel to it. The samples were studied by optical and scanning electron microscopy. The possibility of finding the needle orifece inserted inside the nerve was assessed. On a photographic montage, we counted the number of axons during a hypothetical nerve puncture. Nerve roots used in this study were between 1 and 2.3 mm thick, allowing the needle to penetrate the root in the 52 samples studied. The needle orifice was never fully located inside the nerve in any of the samples. The numbers of myelinized axons affected during nerve punctures 0.2 mm deep were 95, 154, and 81 for Whitacre needles, Quincke needles with the point held perpendicular, or the same needle type held parallel, respectively. During punctures 0.5 mm deep, 472, 602, and 279 were affected for each puncture group, respectively. The differences in all cases were statistically significant. It is possible to achieve intraneural puncture with 25-gauge needles. However, full intraneural placement of the orifice of the needle is unlikely. In case of nerve trauma, the damage could be greater if puncture is carried out with a Quincke needle with the point inserted perpendicular to the nerve root.

Advances in local ablation of malignant liver lesions

PubMed Central

Eisele, Robert M

2016-01-01

Local ablation of liver tumors matured during the recent years and is now proven to be an effective tool in the treatment of malignant liver lesions. Advances focus on the improvement of local tumor control by technical innovations, individual selection of imaging modalities, more accurate needle placement and the free choice of access to the liver. Considering data found in the current literature for conventional local ablative treatment strategies, virtually no single technology is able to demonstrate an unequivocal superiority. Hints at better performance of microwave compared to radiofrequency ablation regarding local tumor control, duration of the procedure and potentially achievable larger size of ablation areas favour the comparably more recent treatment modality; image fusion enables more patients to undergo ultrasound guided local ablation; magnetic resonance guidance may improve primary success rates in selected patients; navigation and robotics accelerate the needle placement and reduces deviation of needle positions; laparoscopic thermoablation results in larger ablation areas and therefore hypothetically better local tumor control under acceptable complication rates, but seems to be limited to patients with no, mild or moderate adhesions following earlier surgical procedures. Apart from that, most techniques appear technically feasible, albeit demanding. Which technology will in the long run become accepted, is subject to future work. PMID:27099433

Interventional robotic systems: Applications and technology state-of-the-art

PubMed Central

CLEARY, KEVIN; MELZER, ANDREAS; WATSON, VANCE; KRONREIF, GERNOT; STOIANOVICI, DAN

2011-01-01

Many different robotic systems have been developed for invasive medical procedures. In this article we will focus on robotic systems for image-guided interventions such as biopsy of suspicious lesions, interstitial tumor treatment, or needle placement for spinal blocks and neurolysis. Medical robotics is a young and evolving field and the ultimate role of these systems has yet to be determined. This paper presents four interventional robotics systems designed to work with MRI, CT, fluoroscopy, and ultrasound imaging devices. The details of each system are given along with any phantom, animal, or human trials. The systems include the AcuBot for active needle insertion under CT or fluoroscopy, the B-Rob systems for needle placement using CT or ultrasound, the INNOMOTION for MRI and CT interventions, and the MRBot for MRI procedures. Following these descriptions, the technology issues of image compatibility, registration, patient movement and respiration, force feedback, and control mode are briefly discussed. It is our belief that robotic systems will be an important part of future interventions, but more research and clinical trials are needed. The possibility of performing new clinical procedures that the human cannot achieve remains an ultimate goal for medical robotics. Engineers and physicians should work together to create and validate these systems for the benefits of patients everywhere. PMID:16754193

Needle Thoracostomy: Does Changing Needle Length and Location Change Patient Outcome?

PubMed

Weichenthal, Lori A; Owen, Scott; Stroh, Geoffory; Ramos, John

2018-06-01

Needle thoracostomy (NT) is a common prehospital intervention for patients in extremis or cardiac arrest due to trauma. The purpose of this study is to compare outcomes, efficacy, and complications after a change in policy related to NT in a four-county Emergency Medical Services (EMS) system with a catchment area of greater than 1.6 million people. This is a before and after observational study of all patients who had NT performed in the Central California (USA) EMS system. The before, anterior midclavicular line (MCL) group consisted of all patients who underwent NT from May 7, 2007 through February 28, 2013. The after, midaxillary line (MAL) axillary group consisted of all patients who underwent NT from March 1, 2013 through January 30, 2016, after policy revisions changed the timing, needle size, and placement location for NT. All prehospital and hospital records where NT was performed were queried for demographics, mechanism of injury, initial status and post-NT clinical change, reported complications, and final outcome. The trauma registry was accessed to obtain Injury Severity Scores (ISS). Information was manually abstracted by study investigators and examined utilizing univariate and multivariate analyses. Three-hundred and five trauma patients treated with NT were included in this study, of which, 169 patients (the MCL group) were treated with a 14-guage intravenous (IV) catheter at least 5.0-cm long at the second intercostal space (ICS), MCL after being placed in the ambulance; and 136 patients (the MAL group) were treated with a 10-guage IV catheter at least 9.5-cm long at the fifth ICS, MAL on scene. The mean ISS was lower in the MAL cohort (64.5 versus 69.2; P=.007). The mortality rate was 79% in both groups. The multivariate model with regard to survival supported that a lower ISS (P<.001) and reported clinical change after NT (P=.003) were significant indicators of survival. No complications from NT were reported. Changing the timing, length of needle, and location of placement did not change mortality in patients requiring NT. Needle thoracostomy was used more frequently after the change in policy, and the MAL cohort was less injured. No increase in reported complications was noted. WeichenthalLA, OwenS, StrohG, RamosJ. Needle thoracostomy: does changing needle length and location change patient outcome? Prehosp Disaster Med. 2018;33(3):237-244.

Real-time three-dimensional optical coherence tomography image-guided core-needle biopsy system.

PubMed

Kuo, Wei-Cheng; Kim, Jongsik; Shemonski, Nathan D; Chaney, Eric J; Spillman, Darold R; Boppart, Stephen A

2012-06-01

Advances in optical imaging modalities, such as optical coherence tomography (OCT), enable us to observe tissue microstructure at high resolution and in real time. Currently, core-needle biopsies are guided by external imaging modalities such as ultrasound imaging and x-ray computed tomography (CT) for breast and lung masses, respectively. These image-guided procedures are frequently limited by spatial resolution when using ultrasound imaging, or by temporal resolution (rapid real-time feedback capabilities) when using x-ray CT. One feasible approach is to perform OCT within small gauge needles to optically image tissue microstructure. However, to date, no system or core-needle device has been developed that incorporates both three-dimensional OCT imaging and tissue biopsy within the same needle for true OCT-guided core-needle biopsy. We have developed and demonstrate an integrated core-needle biopsy system that utilizes catheter-based 3-D OCT for real-time image-guidance for target tissue localization, imaging of tissue immediately prior to physical biopsy, and subsequent OCT imaging of the biopsied specimen for immediate assessment at the point-of-care. OCT images of biopsied ex vivo tumor specimens acquired during core-needle placement are correlated with corresponding histology, and computational visualization of arbitrary planes within the 3-D OCT volumes enables feedback on specimen tissue type and biopsy quality. These results demonstrate the potential for using real-time 3-D OCT for needle biopsy guidance by imaging within the needle and tissue during biopsy procedures.

A parallel row-based algorithm with error control for standard-cell replacement on a hypercube multiprocessor

NASA Technical Reports Server (NTRS)

Sargent, Jeff Scott

1988-01-01

A new row-based parallel algorithm for standard-cell placement targeted for execution on a hypercube multiprocessor is presented. Key features of this implementation include a dynamic simulated-annealing schedule, row-partitioning of the VLSI chip image, and two novel new approaches to controlling error in parallel cell-placement algorithms; Heuristic Cell-Coloring and Adaptive (Parallel Move) Sequence Control. Heuristic Cell-Coloring identifies sets of noninteracting cells that can be moved repeatedly, and in parallel, with no buildup of error in the placement cost. Adaptive Sequence Control allows multiple parallel cell moves to take place between global cell-position updates. This feedback mechanism is based on an error bound derived analytically from the traditional annealing move-acceptance profile. Placement results are presented for real industry circuits and the performance is summarized of an implementation on the Intel iPSC/2 Hypercube. The runtime of this algorithm is 5 to 16 times faster than a previous program developed for the Hypercube, while producing equivalent quality placement. An integrated place and route program for the Intel iPSC/2 Hypercube is currently being developed.

Localization of needle tip with color doppler during pericardiocentesis: In vitro validation and initial clinical application

NASA Technical Reports Server (NTRS)

Armstrong, G.; Cardon, L.; Vilkomerson, D.; Lipson, D.; Wong, J.; Rodriguez, L. L.; Thomas, J. D.; Griffin, B. P.

2001-01-01

This study evaluates a new device that uses color Doppler ultrasonography to enable real-time image guidance of the aspirating needle, which has not been possible until now. The ColorMark device (EchoCath Inc, Princeton, NJ) induces high-frequency, low-amplitude vibrations in the needle to enable localization with color Doppler. We studied this technique in 25 consecutive patients undergoing pericardiocentesis, and in vitro, in a urethane phantom with which the accuracy of color Doppler localization of the needle tip was compared with that obtained by direct measurement. Tip localization was excellent in vitro; errors axial to the ultrasound beam (velocity Doppler -0.13 +/- 0.90 mm, power Doppler -0.05 +/- 1.7 mm) were less than lateral errors (velocity -0.36 +/- 1.8 mm, power -0.02 +/- 2.8 mm). In 18 of 25 patients, the needle was identified and guided into the pericardial space with the ColorMark technique, and it allowed successful, uncomplicated drainage of fluid. Initial failures were the result of incorrect settings on the echocardiographic machine and inappropriate combinations of the needle puncture site and imaging window. This study demonstrates a novel color Doppler technique that is highly accurate at localizing a needle tip. The technique is feasible for guiding pericardiocentesis. Further clinical validation of this technique is required.

Convolution neural networks for real-time needle detection and localization in 2D ultrasound.

PubMed

Mwikirize, Cosmas; Nosher, John L; Hacihaliloglu, Ilker

2018-05-01

We propose a framework for automatic and accurate detection of steeply inserted needles in 2D ultrasound data using convolution neural networks. We demonstrate its application in needle trajectory estimation and tip localization. Our approach consists of a unified network, comprising a fully convolutional network (FCN) and a fast region-based convolutional neural network (R-CNN). The FCN proposes candidate regions, which are then fed to a fast R-CNN for finer needle detection. We leverage a transfer learning paradigm, where the network weights are initialized by training with non-medical images, and fine-tuned with ex vivo ultrasound scans collected during insertion of a 17G epidural needle into freshly excised porcine and bovine tissue at depth settings up to 9 cm and [Formula: see text]-[Formula: see text] insertion angles. Needle detection results are used to accurately estimate needle trajectory from intensity invariant needle features and perform needle tip localization from an intensity search along the needle trajectory. Our needle detection model was trained and validated on 2500 ex vivo ultrasound scans. The detection system has a frame rate of 25 fps on a GPU and achieves 99.6% precision, 99.78% recall rate and an [Formula: see text] score of 0.99. Validation for needle localization was performed on 400 scans collected using a different imaging platform, over a bovine/porcine lumbosacral spine phantom. Shaft localization error of [Formula: see text], tip localization error of [Formula: see text] mm, and a total processing time of 0.58 s were achieved. The proposed method is fully automatic and provides robust needle localization results in challenging scanning conditions. The accurate and robust results coupled with real-time detection and sub-second total processing make the proposed method promising in applications for needle detection and localization during challenging minimally invasive ultrasound-guided procedures.

360-degree 3D transvaginal ultrasound system for high-dose-rate interstitial gynaecological brachytherapy needle guidance

NASA Astrophysics Data System (ADS)

Rodgers, Jessica R.; Surry, Kathleen; D'Souza, David; Leung, Eric; Fenster, Aaron

2017-03-01

Treatment for gynaecological cancers often includes brachytherapy; in particular, in high-dose-rate (HDR) interstitial brachytherapy, hollow needles are inserted into the tumour and surrounding area through a template in order to deliver the radiation dose. Currently, there is no standard modality for visualizing needles intra-operatively, despite the need for precise needle placement in order to deliver the optimal dose and avoid nearby organs, including the bladder and rectum. While three-dimensional (3D) transrectal ultrasound (TRUS) imaging has been proposed for 3D intra-operative needle guidance, anterior needles tend to be obscured by shadowing created by the template's vaginal cylinder. We have developed a 360-degree 3D transvaginal ultrasound (TVUS) system that uses a conventional two-dimensional side-fire TRUS probe rotated inside a hollow vaginal cylinder made from a sonolucent plastic (TPX). The system was validated using grid and sphere phantoms in order to test the geometric accuracy of the distance and volumetric measurements in the reconstructed image. To test the potential for visualizing needles, an agar phantom mimicking the geometry of the female pelvis was used. Needles were inserted into the phantom and then imaged using the 3D TVUS system. The needle trajectories and tip positions in the 3D TVUS scan were compared to their expected values and the needle tracks visualized in magnetic resonance images. Based on this initial study, 360-degree 3D TVUS imaging through a sonolucent vaginal cylinder is a feasible technique for intra-operatively visualizing needles during HDR interstitial gynaecological brachytherapy.

Enabling image fusion for a CT guided needle placement robot

NASA Astrophysics Data System (ADS)

Seifabadi, Reza; Xu, Sheng; Aalamifar, Fereshteh; Velusamy, Gnanasekar; Puhazhendi, Kaliyappan; Wood, Bradford J.

2017-03-01

Purpose: This study presents development and integration of hardware and software that enables ultrasound (US) and computer tomography (CT) fusion for a FDA-approved CT-guided needle placement robot. Having real-time US image registered to a priori-taken intraoperative CT image provides more anatomic information during needle insertion, in order to target hard-to-see lesions or avoid critical structures invisible to CT, track target motion, and to better monitor ablation treatment zone in relation to the tumor location. Method: A passive encoded mechanical arm is developed for the robot in order to hold and track an abdominal US transducer. This 4 degrees of freedom (DOF) arm is designed to attach to the robot end-effector. The arm is locked by default and is released by a press of button. The arm is designed such that the needle is always in plane with US image. The articulated arm is calibrated to improve its accuracy. Custom designed software (OncoNav, NIH) was developed to fuse real-time US image to a priori-taken CT. Results: The accuracy of the end effector before and after passive arm calibration was 7.07mm +/- 4.14mm and 1.74mm +/-1.60mm, respectively. The accuracy of the US image to the arm calibration was 5mm. The feasibility of US-CT fusion using the proposed hardware and software was demonstrated in an abdominal commercial phantom. Conclusions: Calibration significantly improved the accuracy of the arm in US image tracking. Fusion of US to CT using the proposed hardware and software was feasible.

Error analysis of multi-needle Langmuir probe measurement technique.

PubMed

Barjatya, Aroh; Merritt, William

2018-04-01

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.

Error analysis of multi-needle Langmuir probe measurement technique

NASA Astrophysics Data System (ADS)

Barjatya, Aroh; Merritt, William

2018-04-01

Multi-needle Langmuir probe is a fairly new instrument technique that has been flown on several recent sounding rockets and is slated to fly on a subset of QB50 CubeSat constellation. This paper takes a fundamental look into the data analysis procedures used for this instrument to derive absolute electron density. Our calculations suggest that while the technique remains promising, the current data analysis procedures could easily result in errors of 50% or more. We present a simple data analysis adjustment that can reduce errors by at least a factor of five in typical operation.

Thermomechanical characterization of one-way shape memory Nitinol as an actuator for active surgical needle

NASA Astrophysics Data System (ADS)

Honarvar, Mohammad

Needle-based intervention insertion is one of the common surgical techniques used in many diagnostic and therapeutic percutaneous procedures. The success of such procedures highly depends on the accuracy of needle placement at target locations. An active needle has the potential to enhance the accuracy of needle placement as well as to improve clinical outcome. Bending forces provided by the attached actuators can assist the maneuverability in order to reach the targets following a desired trajectory. There are three major research parts in the development of active needle project in the Composites Laboratory of Temple University. They are thermomechanical characterization of shape memory alloy (SMA) or Nitinol as an actuator for smart needle, mechanical modeling and design of smart needles, and study of tissue needle interaction. The characterization of SMA is the focus of this dissertation. Unique thermomechanical properties of Nitinol known as shape memory effect and superelasticity make it applicable for different fields such as biomedical, structural and aerospace engineering. These unique behaviors are due to the comparatively large amount of recoverable strain which is being produced in a martensitic phase transformation. However, under certain ranges of stresses and temperatures, Nitinol wires exhibit unrecovered strain (also known as residual strain); which limits their applicability. Therefore, for applications that rely on the strain response in repetitive loading and unloading cycles, it is important to understand the generation of the unrecovered strain in the Nitinol wires. In this study, the unrecovered strain of Nitinol wires with various diameters was investigated, using two experimental approaches: constant stress and uniaxial tensile tests. Moreover, a critical range of stress was found beyond which the unrecovered strain was negligible at temperatures of 70 to 80°C depending on the wire diameter. Wire diameters varied from 0.10 to 0.29 mm were tested and different ranges of critical stress were found for different wire diameters. The transformation temperatures of different wire diameters at zero stress have been achieved by performing the Differential Scanning Calorimetry (DSC) test. The actuation force created by Nitinol wire is measured through constant strain experiment. X-Ray Diffraction (XRD) study was also performed to investigate the phase of Nitinol wires under various thermomechanical loading conditions. In summary, the effect of wire diameter on the required critical stresses to avoid the unrecovered strain between first and second cycle of heating and cooling are presented and the results of both mechanical tests are justified by the results obtained from the XRD study.

Foramen ovale puncture, lesioning accuracy, and avoiding complications: microsurgical anatomy study with clinical implications.

PubMed

Peris-Celda, Maria; Graziano, Francesca; Russo, Vittorio; Mericle, Robert A; Ulm, Arthur J

2013-11-01

Foramen ovale (FO) puncture allows for trigeminal neuralgia treatment, FO electrode placement, and selected biopsy studies. The goals of this study were to demonstrate the anatomical basis of complications related to FO puncture, and provide anatomical landmarks for improvement of safety, selective lesioning of the trigeminal nerve (TN), and optimal placement of electrodes. Both sides of 50 dry skulls were studied to obtain the distances from the FO to relevant cranial base references. A total of 36 sides from 18 formalin-fixed specimens were dissected for Meckel cave and TN measurements. The best radiographic projection for FO visualization was assessed in 40 skulls, and the optimal trajectory angles, insertion depths, and topographies of the lesions were evaluated in 17 specimens. In addition, the differences in postoperative pain relief after the radiofrequency procedure among different branches of the TN were statistically assessed in 49 patients to determine if there was any TN branch less efficiently targeted. Most severe complications during FO puncture are related to incorrect needle placement intracranially or extracranially. The needle should be inserted 25 mm lateral to the oral commissure, forming an approximately 45° angle with the hard palate in the lateral radiographic view, directed 20° medially in the anteroposterior view. Once the needle reaches the FO, it can be advanced by 20 mm, on average, up to the petrous ridge. If the needle/radiofrequency electrode tip remains more than 18 mm away from the midline, injury to the cavernous carotid artery is minimized. Anatomically there is less potential for complications when the needle/radiofrequency electrode is advanced no more than 2 mm away from the clival line in the lateral view, when the needle pierces the medial part of the FO toward the medial part of the trigeminal impression in the petrous ridge, and no more than 4 mm in the lateral part. The 40°/45° inferior transfacial-20° oblique radiographic projection visualized 96.2% of the FOs in dry skulls, and the remainder were not visualized in any other projection of the radiograph. Patients with V1 involvement experienced postoperative pain more frequently than did patients with V2 or V3 involvement. Anatomical targeting of V1 in specimens was more efficiently achieved by inserting the needle in the medial third of the FO; for V2 targeting, in the middle of the FO; and for V3 targeting, in the lateral third of the FO. Knowledge of the extracranial and intracranial anatomical relationships of the FO is essential to understanding and avoiding complications during FO puncture. These data suggest that better radiographic visualization of the FO can improve lesioning accuracy depending on the part of the FO to be punctured. The angles and safety distances obtained may help the neurosurgeon minimize complications during FO puncture and TN lesioning.

The Effect of Microphone Placement on Interaural Level Differences and Sound Localization Across the Horizontal Plane in Bilateral Cochlear Implant Users.

PubMed

Jones, Heath G; Kan, Alan; Litovsky, Ruth Y

2016-01-01

This study examined the effect of microphone placement on the interaural level differences (ILDs) available to bilateral cochlear implant (BiCI) users, and the subsequent effects on horizontal-plane sound localization. Virtual acoustic stimuli for sound localization testing were created individually for eight BiCI users by making acoustic transfer function measurements for microphones placed in the ear (ITE), behind the ear (BTE), and on the shoulders (SHD). The ILDs across source locations were calculated for each placement to analyze their effect on sound localization performance. Sound localization was tested using a repeated-measures, within-participant design for the three microphone placements. The ITE microphone placement provided significantly larger ILDs compared to BTE and SHD placements, which correlated with overall localization errors. However, differences in localization errors across the microphone conditions were small. The BTE microphones worn by many BiCI users in everyday life do not capture the full range of acoustic ILDs available, and also reduce the change in cue magnitudes for sound sources across the horizontal plane. Acute testing with an ITE placement reduced sound localization errors along the horizontal plane compared to the other placements in some patients. Larger improvements may be observed if patients had more experience with the new ILD cues provided by an ITE placement.

AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: report of Task Group 192.

PubMed

Podder, Tarun K; Beaulieu, Luc; Caldwell, Barrett; Cormack, Robert A; Crass, Jostin B; Dicker, Adam P; Fenster, Aaron; Fichtinger, Gabor; Meltsner, Michael A; Moerland, Marinus A; Nath, Ravinder; Rivard, Mark J; Salcudean, Tim; Song, Danny Y; Thomadsen, Bruce R; Yu, Yan

2014-10-01

In the last decade, there have been significant developments into integration of robots and automation tools with brachytherapy delivery systems. These systems aim to improve the current paradigm by executing higher precision and accuracy in seed placement, improving calculation of optimal seed locations, minimizing surgical trauma, and reducing radiation exposure to medical staff. Most of the applications of this technology have been in the implantation of seeds in patients with early-stage prostate cancer. Nevertheless, the techniques apply to any clinical site where interstitial brachytherapy is appropriate. In consideration of the rapid developments in this area, the American Association of Physicists in Medicine (AAPM) commissioned Task Group 192 to review the state-of-the-art in the field of robotic interstitial brachytherapy. This is a joint Task Group with the Groupe Européen de Curiethérapie-European Society for Radiotherapy & Oncology (GEC-ESTRO). All developed and reported robotic brachytherapy systems were reviewed. Commissioning and quality assurance procedures for the safe and consistent use of these systems are also provided. Manual seed placement techniques with a rigid template have an estimated in vivo accuracy of 3-6 mm. In addition to the placement accuracy, factors such as tissue deformation, needle deviation, and edema may result in a delivered dose distribution that differs from the preimplant or intraoperative plan. However, real-time needle tracking and seed identification for dynamic updating of dosimetry may improve the quality of seed implantation. The AAPM and GEC-ESTRO recommend that robotic systems should demonstrate a spatial accuracy of seed placement ≤1.0 mm in a phantom. This recommendation is based on the current performance of existing robotic brachytherapy systems and propagation of uncertainties. During clinical commissioning, tests should be conducted to ensure that this level of accuracy is achieved. These tests should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot-clinician and robot-patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.

Automatic Multiple-Needle Surgical Planning of Robotic-Assisted Microwave Coagulation in Large Liver Tumor Therapy

PubMed Central

Liu, Shaoli; Xia, Zeyang; Liu, Jianhua; Xu, Jing; Ren, He; Lu, Tong; Yang, Xiangdong

2016-01-01

The “robotic-assisted liver tumor coagulation therapy” (RALTCT) system is a promising candidate for large liver tumor treatment in terms of accuracy and speed. A prerequisite for effective therapy is accurate surgical planning. However, it is difficult for the surgeon to perform surgical planning manually due to the difficulties associated with robot-assisted large liver tumor therapy. These main difficulties include the following aspects: (1) multiple needles are needed to destroy the entire tumor, (2) the insertion trajectories of the needles should avoid the ribs, blood vessels, and other tissues and organs in the abdominal cavity, (3) the placement of multiple needles should avoid interference with each other, (4) an inserted needle will cause some deformation of liver, which will result in changes in subsequently inserted needles’ operating environment, and (5) the multiple needle-insertion trajectories should be consistent with the needle-driven robot’s movement characteristics. Thus, an effective multiple-needle surgical planning procedure is needed. To overcome these problems, we present an automatic multiple-needle surgical planning of optimal insertion trajectories to the targets, based on a mathematical description of all relevant structure surfaces. The method determines the analytical expression of boundaries of every needle “collision-free reachable workspace” (CFRW), which are the feasible insertion zones based on several constraints. Then, the optimal needle insertion trajectory within the optimization criteria will be chosen in the needle CFRW automatically. Also, the results can be visualized with our navigation system. In the simulation experiment, three needle-insertion trajectories were obtained successfully. In the in vitro experiment, the robot successfully achieved insertion of multiple needles. The proposed automatic multiple-needle surgical planning can improve the efficiency and safety of robot-assisted large liver tumor therapy, significantly reduce the surgeon’s workload, and is especially helpful for an inexperienced surgeon. The methodology should be easy to adapt in other body parts. PMID:26982341

Reduced variability and execution time to reach a target with a needle GPS system: Comparison between physicians, residents and nurse anaesthetists.

PubMed

Fevre, Marie-Cécile; Vincent, Caroline; Picard, Julien; Vighetti, Arnaud; Chapuis, Claire; Detavernier, Maxime; Allenet, Benoît; Payen, Jean-François; Bosson, Jean-Luc; Albaladejo, Pierre

2018-02-01

Ultrasound (US) guided needle positioning is safer than anatomical landmark techniques for central venous access. Hand-eye coordination and execution time depend on the professional's ability, previous training and personal skills. Needle guidance positioning systems (GPS) may theoretically reduce execution time and facilitate needle positioning in specific targets, thus improving patient comfort and safety. Three groups of healthcare professionals (41 anaesthesiologists and intensivists, 41 residents in anaesthesiology and intensive care, 39 nurse anaesthetists) were included and required to perform 3 tasks (positioning the tip of a needle in three different targets in a silicon phantom) by using successively a conventional US-guided needle positioning and a needle GPS. We measured execution times to perform the tasks, hand-eye coordination and the number of repositioning occurrences or errors in handling the needle or the probe. Without the GPS system, we observed a significant inter-individual difference for execution time (P<0.05), hand-eye coordination and the number of errors/needle repositioning between physicians, residents and nurse anaesthetists. US training and video gaming were found to be independent factors associated with a shorter execution time. Use of GPS attenuated the inter-individual and group variability. We observed a reduced execution time and improved hand-eye coordination in all groups as compared to US without GPS. Neither US training, video gaming nor demographic personal or professional factors were found to be significantly associated with reduced execution time when GPS was used. US associated with GPS systems may improve safety and decrease execution time by reducing inter-individual variability between professionals for needle-handling procedures. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

Foot placement during error and pedal applications in naturalistic driving.

PubMed

Wu, Yuqing; Boyle, Linda Ng; McGehee, Daniel; Roe, Cheryl A; Ebe, Kazutoshi; Foley, James

2017-02-01

Data from a naturalistic driving study was used to examine foot placement during routine foot pedal movements and possible pedal misapplications. The study included four weeks of observations from 30 drivers, where pedal responses were recorded and categorized. The foot movements associated with pedal misapplications and errors were the focus of the analyses. A random forest algorithm was used to predict the pedal application types based the video observations, foot placements, drivers' characteristics, drivers' cognitive function levels and anthropometric measurements. A repeated multinomial logit model was then used to estimate the likelihood of the foot placement given various driver characteristics and driving scenarios. The findings showed that prior foot location, the drivers' seat position, and the drive sequence were all associated with incorrect foot placement during an event. The study showed that there is a potential to develop a driver assistance system that can reduce the likelihood of a pedal error. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fluoroscopically Guided Epidural Injections of the Cervical and Lumbar Spine.

PubMed

Shim, Euddeum; Lee, Joon Woo; Lee, Eugene; Ahn, Joong Mo; Kang, Yusuhn; Kang, Heung Sik

2017-01-01

Advances in imaging and the development of injection techniques have enabled spinal intervention to become an important tool in managing chronic spinal pain. Epidural steroid injection (ESI) is one of the most widely used spinal interventions; it directly delivers drugs into the epidural space to relieve pain originating from degenerative spine disorders-central canal stenoses and neural foraminal stenoses-or disk herniations. Knowledge of the normal anatomy of the epidural space is essential to perform an effective and safe ESI and to recognize possible complications. Although computed tomographic (CT) or combined CT-fluoroscopic guidance has been increasingly used in ESI, conventional fluoroscopic guidance is generally performed. In ESI, drugs are delivered into the epidural space by interlaminar or transforaminal routes in the cervical spine or by interlaminar, transforaminal, or caudal routes in the lumbar spine. Epidurography is usually performed before drug delivery to verify the proper position of the needle in the epidural space. A small amount of contrast agent is injected with fluoroscopic guidance. Familiarity with the findings on a typical "true" epidurogram (demonstrating correct needle placement in the epidural space) permits proper performance of ESI. Findings on "false" epidurograms (demonstrating incorrect needle placement) include muscular staining and evidence of intravascular injection, inadvertent facet joint injection, dural puncture, subdural injection, and intraneural or intradiscal injection. © RSNA, 2016 An earlier incorrect version of this article appeared online. This article was corrected on December 22, 2016.

Two-dimensional mapping of needle visibility with linear and curved array for ultrasound-guided interventional procedure

NASA Astrophysics Data System (ADS)

Susanti, Hesty; Suprijanto, Kurniadi, Deddy

2018-02-01

Needle visibility in ultrasound-guided technique has been a crucial factor for successful interventional procedure. It has been affected by several factors, i.e. puncture depth, insertion angle, needle size and material, and imaging technology. The influences of those factors made the needle not always well visible. 20 G needles of 15 cm length (Nano Line, facet) were inserted into water bath with variation of insertion angles and depths. Ultrasound measurements are performed with BK-Medical Flex Focus 800 using 12 MHz linear array and 5 MHz curved array in Ultrasound Guided Regional Anesthesia mode. We propose 3 criteria to evaluate needle visibility, i.e. maximum intensity, mean intensity, and the ratio between minimum and maximum intensity. Those criteria were then depicted into representative maps for practical purpose. The best criterion candidate for representing the needle visibility was criterion 1. Generally, the appearance pattern of the needle from this criterion was relatively consistent, i.e. for linear array, it was relatively poor visibility in the middle part of the shaft, while for curved array, it is relatively better visible toward the end of the shaft. With further investigations, for example with the use of tissue-mimicking phantom, the representative maps can be built for future practical purpose, i.e. as a tool for clinicians to ensure better needle placement in clinical application. It will help them to avoid the "dead" area where the needle is not well visible, so it can reduce the risks of vital structures traversing and the number of required insertion, resulting in less patient morbidity. Those simple criteria and representative maps can be utilized to evaluate general visibility patterns of the needle in vast range of needle types and sizes in different insertion media. This information is also important as an early investigation for future research of needle visibility improvement, i.e. the development of beamforming strategies and ultrasound enhanced (echogenic) needle.

Characterization of optically actuated MRI-compatible active needles for medical interventions

NASA Astrophysics Data System (ADS)

Black, Richard J.; Ryu, Seokchang; Moslehi, Behzad; Costa, Joannes M.

2014-03-01

The development of a Magnetic Resonance Imaging (MRI) compatible optically-actuated active needle for guided percutaneous surgery and biopsy procedures is described. Electrically passive MRI-compatible actuation in the small diameter needle is provided by non-magnetic materials including a shape memory alloy (SMA) subject to precise fiber laser operation that can be from a remote (e.g., MRI control room) location. Characterization and optimization of the needle is facilitated using optical fiber Bragg grating (FBG) temperature sensors arrays. Active bending of the needle during insertion allows the needle to be accurately guided to even relatively small targets in an organ while avoiding obstacles and overcoming undesirable deviations away from the planned path due to unforeseen or unknowable tissue interactions. This feature makes the needle especially suitable for use in image-guided surgical procedures (ranging from MRI to CT and ultrasound) when accurate targeting is imperative for good treatment outcomes. Such interventions include reaching small tumors in biopsies, delineating freezing areas in, for example, cryosurgery and improving the accuracy of seed placement in brachytherapy. Particularly relevant are prostate procedures, which may be subject to pubic arch interference. Combining diagnostic imaging and actuation assisted biopsy into one treatment can obviate the need for a second exam for guided biopsy, shorten overall procedure times (thus increasing operating room efficiencies), address healthcare reimbursement constraints and, most importantly, improve patient comfort and clinical outcomes.

A new technical contribution for ultrasound-guided injections of sacro-iliac joints.

PubMed

Migliore, A; Bizzi, E; Massafra, U; Vacca, F; Martin-Martin, L S; Granata, M; Tormenta, S

2010-05-01

Sacroiliac joint (SIJ) represents a difficult location for local therapies, as intra-articular injections may be hard to execute, especially in particular conditions such as chronic inflammatory diseases. However, in selected patients, local therapies may be considered. Some recent studies demonstrated the feasibility of ultrasound (US)-guided injection of SIJ, but still a complete explanation and definition of the technique is needed. Seven patients, four males and 3 females, affected by mono or bilateral sacroiliitis entered the study. Each patient received 40 mg of acetonide triamcinolone for each SIJ, intra articular (IA) US-guided injection. The technical originality proposed in this study consists in the spinal needle insertion in the middle of the cranial long side of the linear transducer with an orientation of about 10 degrees, determining shorter needle insertion for reaching joint space and consequently probably granting lesser pain and traumatism for patients. A total of 22 injections was performed. The longer follow-up time obtained was 18 months in 3 patients. All patients reached at least a 6 month follow-up. All patients reported an amelioration in pain that lasted for at least 6 months. No systemic adverse events were reported or observed. Complete visualization of SIJ and of needle placement was performed by US imaging, while compound proper injection was also visualized by Color-Doppler US imaging. Actually, sacroiliac joint intraarticular injections are often performed under fluoroscopy or Computerized Tomography guidance. Such techniques present several limitations, especially for repeated injections, such as the use of ionizing radiations, the need of a contrast agent and the direct and indirect costs connected. US guidance in IA SIJ injections may represent an easily repeatable imaging technique for needle placement and a precious tool for detecting inflammatory activity of the joint.

The Relationship Between Technical Errors and Decision Making Skills in the Junior Resident

PubMed Central

Nathwani, J. N.; Fiers, R.M.; Ray, R.D.; Witt, A.K.; Law, K. E.; DiMarco, S.M.; Pugh, C.M.

2017-01-01

Objective The purpose of this study is to co-evaluate resident technical errors and decision-making capabilities during placement of a subclavian central venous catheter (CVC). We hypothesize that there will be significant correlations between scenario based decision making skills, and technical proficiency in central line insertion. We also predict residents will have problems in anticipating common difficulties and generating solutions associated with line placement. Design Participants were asked to insert a subclavian central line on a simulator. After completion, residents were presented with a real life patient photograph depicting CVC placement and asked to anticipate difficulties and generate solutions. Error rates were analyzed using chi-square tests and a 5% expected error rate. Correlations were sought by comparing technical errors and scenario based decision making. Setting This study was carried out at seven tertiary care centers. Participants Study participants (N=46) consisted of largely first year research residents that could be followed longitudinally. Second year research and clinical residents were not excluded. Results Six checklist errors were committed more often than anticipated. Residents performed an average of 1.9 errors, significantly more than the 1 error, at most, per person expected (t(44)=3.82, p<.001). The most common error was performance of the procedure steps in the wrong order (28.5%, P<.001). Some of the residents (24%) had no errors, 30% committed one error, and 46 % committed more than one error. The number of technical errors committed negatively correlated with the total number of commonly identified difficulties and generated solutions (r(33)= −.429, p=.021, r(33)= −.383, p=.044 respectively). Conclusions Almost half of the surgical residents committed multiple errors while performing subclavian CVC placement. The correlation between technical errors and decision making skills suggests a critical need to train residents in both technique and error management. ACGME Competencies Medical Knowledge, Practice Based Learning and Improvement, Systems Based Practice PMID:27671618

Mathematics Course Placement Using Holistic Measures: Possibilities for Community College Students

ERIC Educational Resources Information Center

Ngo, Federick; Chi, W. Edward; Park, Elizabeth So Yun

2018-01-01

Background/Context: Most community colleges across the country use a placement test to determine students' readiness for college-level coursework, yet these tests are admittedly imperfect instruments. Researchers have documented significant problems stemming from overreliance on placement testing, including placement error and misdiagnosis of…

CT fluoroscopy guided transpleural cutting needle biopsy of small (≤2.5 cm) subpleural pulmonary nodules.

PubMed

Prosch, Helmut; Oschatz, Elisabeth; Eisenhuber, Edith; Wohlschlager, Helmut; Mostbeck, Gerhard H

2011-01-01

Small subpleural pulmonary lesions are difficult to biopsy. While the direct, short needle path has been reported to have a lower rate of pneumothorax, the indirect path provides a higher diagnostic yield. Therefore, we tried to optimize the needle pathway and minimize the iatrogenic pneumothorax risk by evaluating a CT fluoroscopy guided direct approach to biopsy subpleural lesions. Between 01/2005 and 01/2007, CT fluoroscopy guided core biopsies were performed in 24 patients. Using our technique, the tip of the guide needle remains outside the visceral pleura (17 G coaxial guide needle, 18 G Biopsy-gun, 15 or 22 mm needle path). The position of the lesion relative to the needle tip can be optimized using CT fluoroscopy by adjusting the breathing position of the patient. The Biopty gun is fired with the needle tip still outside the pleural space. Cytological smears are analyzed by a cytopathologist on-site, and biopsies are repeated as indicated with the coaxial needle still outside the pleura. Median nodule size was 1.6 cm (0.7-2.3 cm). A definitive diagnosis was obtained in 22 patients by histology and/or cytology. In one patient, only necrotic material could be obtained. In another patient, the intervention had to be aborted as the dyspnoic patient could not follow breathing instructions. An asymptomatic pneumothorax was present in seven patients; chest tube placement was not required. The presented biopsy approach has a high diagnostic yield and is especially advantageous for biopsies of small subpleural lesions in the lower lobes. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

WE-A-17A-09: Exploiting Electromagnetic Technologies for Real-Time Seed Drop Position Validation in Permanent Implant Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Racine, E; Hautvast, G; Binnekamp, D

Purpose: To report on preliminary results validating the performance of a specially designed LDR brachytherapy needle prototype possessing both electromagnetic (EM) tracking and seed drop detection abilities. Methods: An EM hollow needle prototype has been designed and constructed in collaboration with research partner Philips Healthcare. The needle possesses conventional 3D tracking capabilities, along with a novel seed drop detection mechanism exploiting local changes of electromagnetic properties generated by the passage of seeds in the needle's embedded sensor coils. These two capabilities are exploited by proprietary engineering and signal processing techniques to generate seed drop position estimates in real-time treatment delivery.more » The electromagnetic tracking system (EMTS) used for the experiment is the NDI Aurora Planar Field Generator. The experiment consisted of dropping a total of 35 seeds in a prismatic agarose phantom, and comparing the 3D seed drop positions of the EMTS to those obtained by an image analysis of subsequent micro-CT scans. Drop position error computations and statistical analysis were performed after a 3D registration of the two seed distributions. Results: Of the 35 seeds dropped in the phantom, 32 were properly detected by the needle prototype. Absolute drop position errors among the detected seeds ranged from 0.5 to 4.8 mm with mean and standard deviation values of 1.6 and 0.9 mm, respectively. Error measurements also include undesirable and uncontrollable effects such as seed motion upon deposition. The true accuracy performance of the needle prototype is therefore underestimated. Conclusion: This preliminary study demonstrates the potential benefits of EM technologies in detecting the passage of seeds in a hollow needle as a means of generating drop position estimates in real-time treatment delivery. Such tools could therefore represent a potentially interesting addition to existing brachytherapy protocols for rapid dosimetry validation. Equipments and fundings for this project were provided by Philips Medical.« less

Computed tomography (CT)-compatible remote center of motion needle steering robot: Fusing CT images and electromagnetic sensor data.

PubMed

Shahriari, Navid; Heerink, Wout; van Katwijk, Tim; Hekman, Edsko; Oudkerk, Matthijs; Misra, Sarthak

2017-07-01

Lung cancer is the most common cause of cancer-related death, and early detection can reduce the mortality rate. Patients with lung nodules greater than 10 mm usually undergo a computed tomography (CT)-guided biopsy. However, aligning the needle with the target is difficult and the needle tends to deflect from a straight path. In this work, we present a CT-compatible robotic system, which can both position the needle at the puncture point and also insert and rotate the needle. The robot has a remote-center-of-motion arm which is achieved through a parallel mechanism. A new needle steering scheme is also developed where CT images are fused with electromagnetic (EM) sensor data using an unscented Kalman filter. The data fusion allows us to steer the needle using the real-time EM tracker data. The robot design and the steering scheme are validated using three experimental cases. Experimental Case I and II evaluate the accuracy and CT-compatibility of the robot arm, respectively. In experimental Case III, the needle is steered towards 5 real targets embedded in an anthropomorphic gelatin phantom of the thorax. The mean targeting error for the 5 experiments is 1.78 ± 0.70 mm. The proposed robotic system is shown to be CT-compatible with low targeting error. Small nodule size and large needle diameter are two risk factors that can lead to complications in lung biopsy. Our results suggest that nodules larger than 5 mm in diameter can be targeted using our method which may result in lower complication rate. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Effectiveness of Toyota process redesign in reducing thyroid gland fine-needle aspiration error.

PubMed

Raab, Stephen S; Grzybicki, Dana Marie; Sudilovsky, Daniel; Balassanian, Ronald; Janosky, Janine E; Vrbin, Colleen M

2006-10-01

Our objective was to determine whether the Toyota Production System process redesign resulted in diagnostic error reduction for patients who underwent cytologic evaluation of thyroid nodules. In this longitudinal, nonconcurrent cohort study, we compared the diagnostic error frequency of a thyroid aspiration service before and after implementation of error reduction initiatives consisting of adoption of a standardized diagnostic terminology scheme and an immediate interpretation service. A total of 2,424 patients underwent aspiration. Following terminology standardization, the false-negative rate decreased from 41.8% to 19.1% (P = .006), the specimen nondiagnostic rate increased from 5.8% to 19.8% (P < .001), and the sensitivity increased from 70.2% to 90.6% (P < .001). Cases with an immediate interpretation had a lower noninterpretable specimen rate than those without immediate interpretation (P < .001). Toyota process change led to significantly fewer diagnostic errors for patients who underwent thyroid fine-needle aspiration.

A technique for open trocar placement in laparoscopic surgery using the umbilical cicatrix tube.

PubMed

Lal, Pawanindra; Sharma, R; Chander, R; Ramteke, V K

2002-09-01

Increasingly the open method for placement of the initial or first trocar is replacing the conventional technique with the Veress needle. Indeed, it is preferred because it affords peritoneal access under direct vision. A number of methods have been described in the literature using a variety of approaches and different instruments. We describe a method of open trocar placement in the supra- or subumbilical region that follows a stepwise procedure and employs specific instruments sequentially, while utilizing the umbilical cicatrix pillar or tube. This technique has been done in 525 cases with no complications or port site hernias. This is a simple technique that is safe and easy to learn. It can be performed rapidly and is a reliable method for the insertion of the first port under vision.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGraw, J. Kevin; Strnad, Bradley T.; Patzik, Shayle B.

Percutaneous vertebroplasty with polymethylmethacrylate (PMMA) is an effective procedure for relieving pain due to vertebral body compression fractures. The technique employs iodinated contrast venography to exclude needle placement directly within the basivertebral complex. We present two cases in which carbon dioxide (CO{sub 2}) and gadopentetate dimeglumine venography was used to guide percutaneous vertebroplasty in patients with a contraindication to iodinated contrast.

Imaging behind opaque obstacle: a potential method for guided in vitro needle placement

PubMed Central

Perinchery, Sandeep Menon; Shinde, Anant; Matham, Murukeshan Vadakke

2016-01-01

We report a simple real time optical imaging concept using an axicon lens to image the object kept behind opaque obstacles in free space. The proposed concept underlines the importance and advantages of using an axicon lens compared to a conventional lens to image behind the obstacle. The potential of this imaging concept is demonstrated by imaging the insertion of surgical needle in biological specimen in real time, without blocking the field of view. It is envisaged that this proposed concepts and methodology can make a telling impact in a wide variety of areas especially for diagnostics, therapeutics and microscopy applications. PMID:28018744

Modeling Cryotherapy Ice Ball Dimensions and Isotherms in a Novel Gel-based Model to Determine Optimal Cryo-needle Configurations and Settings for Potential Use in Clinical Practice

PubMed Central

Shah, Taimur T.; Arbel, Uri; Foss, Sonja; Zachman, Andrew; Rodney, Simon; Ahmed, Hashim U.; Arya, Manit

2016-01-01

Objective To gain a better understanding of ice ball dimensions and temperature isotherms relevant for cell kill when using combinations of cryo-needles we set out to answer 4 questions: (1) what type of cryo-needle? (2) how many needles? (3) best spatial configuration? and (4) correct duty cycle percentage? Methods We conducted laboratory experiments to monitor ice ball dimensions and create multi-needle planar isotherm maps for 17G and 10G cryo-needles using a novel multi-needle thermocouple fixture within gel at body temperature. We tested configurations of 1-4 cryo-needles at duty cycles of 20%-100% with 1-2.5 cm spacing. Results Analysis of various combinations shows that a central core of ≤−40°C develops at a distance of ~1 cm around the cryo-needles. Temperature increases linearly from this point to the ice ball leading edge (0°C), which is a further ≈1 cm away. Thus, the −40°C isotherm is approximately 1 cm inside the leading edge of the ice ball. The optimum distance between cryo-needles was 1.5-2 cm, at duty cycle settings of 70%-100%. At distances further apart or with lower duty cycle settings, ice balls either had a central core >−40°C or had an hourglass shape. Conclusion In answer to questions 1-3, tumor length, diameter, and shape will ultimately determine the number of needles and their configuration. However, we propose a conservative distance for cryo-needle placement between 1 and 1.5 cm should be adopted for clinical practice. In answer to question 4, using low duty cycle settings runs the risk of incomplete −40°C isotherm coverage of the tumor, and thus in routine practice we suggest that settings of 70%-100% are most appropriate. PMID:26902833

Novel ex vivo model for hands-on teaching of and training in EUS-guided biliary drainage: creation of "Mumbai EUS" stereolithography/3D printing bile duct prototype (with videos).

PubMed

Dhir, Vinay; Itoi, Takao; Fockens, Paul; Perez-Miranda, Manuel; Khashab, Mouen A; Seo, Dong Wan; Yang, Ai Ming; Lawrence, Khek Yu; Maydeo, Amit

2015-02-01

EUS-guided biliary drainage (EUS-BD) has emerged as an alternative rescue method in patients with failed ERCP. Opportunities for teaching and training are limited because of a low case volume at most centers. To evaluate a stereolithography/3-dimensional (3D) printing bile duct prototype for teaching and training in EUS-BD. Prospective observational feasibility study. Tertiary referral center. Twenty endosonographers attending an interventional EUS workshop. A prototype of a dilated biliary system was prepared by computer-aided design and 3D printing. The study participants performed guidewire manipulation and EUS-BD procedures (antegrade procedure and/or choledochoduodenostomy) on the prototype. Participants were scored with the device on a scale of 1 to 5 via a questionnaire. Participants' success rate for various steps of the EUS-BD procedure was noted. Subjective and objective evaluation of the prototype regarding its overall applicability, quality of radiographic and EUS images, and 4 steps of EUS-BD procedure (needle puncture, guidewire manipulation, tract dilation, stent placement). Fifteen participants returned the questionnaire, and 10 completed all 4 steps of EUS-BD. The median score for overall utility was 4, whereas that for EUS and US views was 5. Participants with experience in performing more than 20 EUS-BD procedures scored the prototype significantly lower for stent placement (P = .013) and equivalent for needle puncture, tract dilation, and wire manipulation. The success rate of various steps was 100% for needle puncture and tract dilation, 82.35% for wire manipulation, and 80% for stent placement. The mean overall procedure time was 18 minutes. Small number of participants. The 3D printing bile duct prototype appears suitable for teaching of and training in the various steps of EUS-BD. Further studies are required to elucidate its role. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Electrodiagnostic Evaluation of Individuals Implanted With Extracellular Matrix for the Treatment of Volumetric Muscle Injury: Case Series

PubMed Central

Han, Nami; Yabroudi, Mohammad A.; Stearns-Reider, Kristen; Helkowski, Wendy; Sicari, Brian M.; Rubin, J. Peter; Badylak, Stephen F.; Boninger, Michael L.

2016-01-01

Background Electrodiagnosis can reveal the nerve and muscle changes following surgical placement of an extracellular matrix (ECM) bioscaffold for treatment of volumetric muscle loss (VML). Objective The purpose of this study was to characterize nerve conduction study (NCS) and electromyography (EMG) changes following ECM bioscaffold placement in individuals with VML. The ability of presurgical NCS and EMG to be used as a tool to help identify candidates who are likely to display improvements postsurgically also was explored. Design A longitudinal case series design was used. Methods The study was conducted at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh. Eight individuals with a history of chronic VML participated. The intervention was surgical placement of an ECM bioscaffold at the site of VML. The strength of the affected region was measured using a handheld dynamometer, and electrophysiologic evaluation was conducted on the affected limb with standard method of NCS and EMG. All measurements were obtained the day before surgery and repeated 6 months after surgery. Results Seven of the 8 participants had a preoperative electrodiagnosis of incomplete mononeuropathy within the site of VML. After ECM treatment, 5 of the 8 participants showed improvements in NCS amplitude or needle EMG parameters. The presence of electrical activity within the scaffold remodeling site was concomitant with clinical improvement in muscle strength. Limitations This study had a small sample size, and participants served as their own controls. The electromyographers and physical therapists performing the evaluation were not blinded. Conclusions Electrodiagnostic data provide objective evidence of physiological improvements in muscle function following ECM placement at sites of VML. Future studies are warranted to further investigate the potential of needle EMG as a predictor of successful outcomes following ECM treatment for VML. PMID:26564252

Three-dimensional Image Fusion Guidance for Transjugular Intrahepatic Portosystemic Shunt Placement.

PubMed

Tacher, Vania; Petit, Arthur; Derbel, Haytham; Novelli, Luigi; Vitellius, Manuel; Ridouani, Fourat; Luciani, Alain; Rahmouni, Alain; Duvoux, Christophe; Salloum, Chady; Chiaradia, Mélanie; Kobeiter, Hicham

2017-11-01

To assess the safety, feasibility and effectiveness of image fusion guidance with pre-procedural portal phase computed tomography with intraprocedural fluoroscopy for transjugular intrahepatic portosystemic shunt (TIPS) placement. All consecutive cirrhotic patients presenting at our interventional unit for TIPS creation from January 2015 to January 2016 were prospectively enrolled. Procedures were performed under general anesthesia in an interventional suite equipped with flat panel detector, cone-beam computed tomography (CBCT) and image fusion technique. All TIPSs were placed under image fusion guidance. After hepatic vein catheterization, an unenhanced CBCT acquisition was performed and co-registered with the pre-procedural portal phase CT images. A virtual path between hepatic vein and portal branch was made using the virtual needle path trajectory software. Subsequently, the 3D virtual path was overlaid on 2D fluoroscopy for guidance during portal branch cannulation. Safety, feasibility, effectiveness and per-procedural data were evaluated. Sixteen patients (12 males; median age 56 years) were included. Procedures were technically feasible in 15 of the 16 patients (94%). One procedure was aborted due to hepatic vein catheterization failure related to severe liver distortion. No periprocedural complications occurred within 48 h of the procedure. The median dose-area product was 91 Gy cm 2 , fluoroscopy time 15 min, procedure time 40 min and contrast media consumption 65 mL. Clinical benefit of the TIPS placement was observed in nine patients (56%). This study suggests that 3D image fusion guidance for TIPS is feasible, safe and effective. By identifying virtual needle path, CBCT enables real-time multiplanar guidance and may facilitate TIPS placement.

AAPM and GEC-ESTRO guidelines for image-guided robotic brachytherapy: Report of Task Group 192

DOE Office of Scientific and Technical Information (OSTI.GOV)

Podder, Tarun K., E-mail: tarun.podder@uhhospitals.org; Beaulieu, Luc; Caldwell, Barrett

In the last decade, there have been significant developments into integration of robots and automation tools with brachytherapy delivery systems. These systems aim to improve the current paradigm by executing higher precision and accuracy in seed placement, improving calculation of optimal seed locations, minimizing surgical trauma, and reducing radiation exposure to medical staff. Most of the applications of this technology have been in the implantation of seeds in patients with early-stage prostate cancer. Nevertheless, the techniques apply to any clinical site where interstitial brachytherapy is appropriate. In consideration of the rapid developments in this area, the American Association of Physicistsmore » in Medicine (AAPM) commissioned Task Group 192 to review the state-of-the-art in the field of robotic interstitial brachytherapy. This is a joint Task Group with the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO). All developed and reported robotic brachytherapy systems were reviewed. Commissioning and quality assurance procedures for the safe and consistent use of these systems are also provided. Manual seed placement techniques with a rigid template have an estimated in vivo accuracy of 3–6 mm. In addition to the placement accuracy, factors such as tissue deformation, needle deviation, and edema may result in a delivered dose distribution that differs from the preimplant or intraoperative plan. However, real-time needle tracking and seed identification for dynamic updating of dosimetry may improve the quality of seed implantation. The AAPM and GEC-ESTRO recommend that robotic systems should demonstrate a spatial accuracy of seed placement ≤1.0 mm in a phantom. This recommendation is based on the current performance of existing robotic brachytherapy systems and propagation of uncertainties. During clinical commissioning, tests should be conducted to ensure that this level of accuracy is achieved. These tests should mimic the real operating procedure as closely as possible. Additional recommendations on robotic brachytherapy systems include display of the operational state; capability of manual override; documented policies for independent check and data verification; intuitive interface displaying the implantation plan and visualization of needle positions and seed locations relative to the target anatomy; needle insertion in a sequential order; robot–clinician and robot–patient interactions robustness, reliability, and safety while delivering the correct dose at the correct site for the correct patient; avoidance of excessive force on radioactive sources; delivery confirmation of the required number or position of seeds; incorporation of a collision avoidance system; system cleaning, decontamination, and sterilization procedures. These recommendations are applicable to end users and manufacturers of robotic brachytherapy systems.« less

CT-guided injection of the anterior and middle scalene muscles: technique and complications.

PubMed

Mashayekh, A; Christo, P J; Yousem, D M; Pillai, J J

2011-03-01

Anterior scalene block is a helpful diagnostic test for NTOS and a good predictor of surgical outcome. The purpose of this study was to describe the technique, success rate, and complications associated with CT-guided anesthetic and botulinum toxin injection of the ASM/MSM in patients with NTOS symptoms. One hundred six participants (mean age, 41.5 ± 10 years; 80 women) were identified via a retrospective review of medical records for CT-guided scalene blocks. The procedure was evaluated regarding the technical success, defined as satisfactory detection of the ASM/MSM; intramuscular needle placement; intramuscular injection of contrast; appropriate delivery of medication; and frequency of unintended BP block or other complications. We also determined the outcome of patients who underwent surgery following the block. Study participants underwent 146 scalene injections, 83 blocks, and 63 chemodenervations, which were included in this investigation. In all cases, detection of the ASM/MSM and intramuscular needle placement was satisfactory. Postprocedural complications included 5 (3.4%) temporary BP blocks, 1 patient with (0.7%) Horner sign, 7 (4.8%) needle-induced pain reports, 1 (0.7%) case of dysphagia, and 2 (1.4%) instances of muscle weakness. There were no major complications reported. The rate of good outcome following surgery was the same in patients with positive versus negative blocks, 30/43 (70%) versus 5/7 (71%), respectively. CT guidance is a useful adjunct in performing accurate ASM/MSM blocks with a low rate of minor complications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borot de Battisti, M; Maenhout, M; Lagendijk, J J W

Purpose: To develop adaptive planning with feedback for MRI-guided focal HDR prostate brachytherapy with a single divergent needle robotic implant device. After each needle insertion, the dwell positions for that needle are calculated and the positioning of remaining needles and dosimetry are both updated based on MR imaging. Methods: Errors in needle positioning may occur due to inaccurate needle insertion (caused by e.g. the needle’s bending) and unpredictable changes in patient anatomy. Consequently, the dose plan quality might dramatically decrease compared to the preplan. In this study, a procedure was developed to re-optimize, after each needle insertion, the remaining needlemore » angulations, source positions and dwell times in order to obtain an optimal coverage (D95% PTV>19 Gy) without exceeding the constraints of the organs at risk (OAR) (D10% urethra<21 Gy, D1cc bladder<12 Gy and D1cc rectum<12 Gy). Complete HDR procedures with 6 needle insertions were simulated for a patient MR-image set with PTV, prostate, urethra, bladder and rectum delineated. Random angulation errors, modeled by a Gaussian distribution (standard deviation of 3 mm at the needle’s tip), were generated for each needle insertion. We compared the final dose parameters for the situations (I) without re-optimization and (II) with the automatic feedback. Results: The computation time of replanning was below 100 seconds on a current desk computer. For the patient tested, a clinically acceptable dose plan was achieved while applying the automatic feedback (median(range) in Gy, D95% PTV: 19.9(19.3–20.3), D10% urethra: 13.4(11.9–18.0), D1cc rectum: 11.0(10.7–11.6), D1cc bladder: 4.9(3.6–6.8)). This was not the case without re-optimization (median(range) in Gy, D95% PTV: 19.4(14.9–21.3), D10% urethra: 12.6(11.0–15.7), D1cc rectum: 10.9(8.9–14.1), D1cc bladder: 4.8(4.4–5.2)). Conclusion: An automatic guidance strategy for HDR prostate brachytherapy was developed to compensate errors in needle positioning and improve the dose distribution. Without re-optimization, target coverage and OAR constraints may not be achieved. M. Borot de Battisti is funded by Philips Medical Systems Nederland B.V.; M. Moerland is principal investigator on a contract funded by Philips Medical Systems Nederland B.V.; G. Hautvast and D. Binnekamp are full-time employees of Philips Medical Systems Nederland B.V.« less

Smartphone-Guided Needle Angle Selection During CT-Guided Procedures.

PubMed

Xu, Sheng; Krishnasamy, Venkatesh; Levy, Elliot; Li, Ming; Tse, Zion Tsz Ho; Wood, Bradford John

2018-01-01

In CT-guided intervention, translation from a planned needle insertion angle to the actual insertion angle is estimated only with the physician's visuospatial abilities. An iPhone app was developed to reduce reliance on operator ability to estimate and reproduce angles. The iPhone app overlays the planned angle on the smartphone's camera display in real-time based on the smartphone's orientation. The needle's angle is selected by visually comparing the actual needle with the guideline in the display. If the smartphone's screen is perpendicular to the planned path, the smartphone shows the Bull's-Eye View mode, in which the angle is selected after the needle's hub overlaps the tip in the camera. In phantom studies, we evaluated the accuracies of the hardware, the Guideline mode, and the Bull's-Eye View mode and showed the app's clinical efficacy. A proof-of-concept clinical case was also performed. The hardware accuracy was 0.37° ± 0.27° (mean ± SD). The mean error and navigation time were 1.0° ± 0.9° and 8.7 ± 2.3 seconds for a senior radiologist with 25 years' experience and 1.5° ± 1.3° and 8.0 ± 1.6 seconds for a junior radiologist with 4 years' experience. The accuracy of the Bull's-Eye View mode was 2.9° ± 1.1°. Combined CT and smart-phone guidance was significantly more accurate than CT-only guidance for the first needle pass (p = 0.046), which led to a smaller final targeting error (mean distance from needle tip to target, 2.5 vs 7.9 mm). Mobile devices can be useful for guiding needle-based interventions. The hardware is low cost and widely available. The method is accurate, effective, and easy to implement.

Accuracy of lesion boundary tracking in navigated breast tumor excision

NASA Astrophysics Data System (ADS)

Heffernan, Emily; Ungi, Tamas; Vaughan, Thomas; Pezeshki, Padina; Lasso, Andras; Gauvin, Gabrielle; Rudan, John; Engel, C. Jay; Morin, Evelyn; Fichtinger, Gabor

2016-03-01

PURPOSE: An electromagnetic navigation system for tumor excision in breast conserving surgery has recently been developed. Preoperatively, a hooked needle is positioned in the tumor and the tumor boundaries are defined in the needle coordinate system. The needle is tracked electromagnetically throughout the procedure to localize the tumor. However, the needle may move and the tissue may deform, leading to errors in maintaining a correct excision boundary. It is imperative to quantify these errors so the surgeon can choose an appropriate resection margin. METHODS: A commercial breast biopsy phantom with several inclusions was used. Location and shape of a lesion before and after mechanical deformation were determined using 3D ultrasound volumes. Tumor location and shape were estimated from initial contours and tracking data. The difference in estimated and actual location and shape of the lesion after deformation was quantified using the Hausdorff distance. Data collection and analysis were done using our 3D Slicer software application and PLUS toolkit. RESULTS: The deformation of the breast resulted in 3.72 mm (STD 0.67 mm) average boundary displacement for an isoelastic lesion and 3.88 mm (STD 0.43 mm) for a hyperelastic lesion. The difference between the actual and estimated tracked tumor boundary was 0.88 mm (STD 0.20 mm) for the isoelastic and 1.78 mm (STD 0.18 mm) for the hyperelastic lesion. CONCLUSION: The average lesion boundary tracking error was below 2mm, which is clinically acceptable. We suspect that stiffness of the phantom tissue affected the error measurements. Results will be validated in patient studies.

Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study.

PubMed

Putzer, D; Arco, D; Schamberger, B; Schanda, F; Mahlknecht, J; Widmann, G; Schullian, P; Jaschke, W; Bale, R

2016-05-01

We compared the targeting accuracy and reliability of two different electromagnetic navigation systems for manually guided punctures in a phantom. CT data sets of a gelatin filled plexiglass phantom were acquired with 1, 3, and 5 mm slice thickness. After paired-point registration of the phantom, a total of 480 navigated stereotactic needle insertions were performed manually using electromagnetic guidance with two different navigation systems (Medtronic Stealth Station: AxiEM; Philips: PercuNav). A control CT was obtained to measure the target positioning error between the planned and actual needle trajectory. Using the Philips PercuNav, the accomplished Euclidean distances were 4.42 ± 1.33 mm, 4.26 ± 1.32 mm, and 4.46 ± 1.56 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.84 ± 1.59 mm, 3.84 ± 1.43 mm, and 3.81 ± 1.71 mm, respectively. Using the Medtronic Stealth Station AxiEM, the Euclidean distances were 3.86 ± 2.28 mm, 3.74 ± 2.1 mm, and 4.81 ± 2.07 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.29 ± 1.52 mm, 3.16 ± 1.52 mm, and 3.93 ± 1.68 mm, respectively. Both electromagnetic navigation devices showed excellent results regarding puncture accuracy in a phantom model. The Medtronic Stealth Station AxiEM provided more accurate results in comparison to the Philips PercuNav for CT with 3 mm slice thickness. One potential benefit of electromagnetic navigation devices is the absence of visual contact between the instrument and the sensor system. Due to possible interference with metal objects, incorrect position sensing may occur. In contrast to the phantom study, patient movement including respiration has to be compensated for in the clinical setting. • Commercially available electromagnetic navigation systems have the potential to improve the therapeutic range for CT guided percutaneous procedures by comparing the needle placement accuracy on the basis of planning CT data sets with different slice thickness. Citation Format: • Putzer D, Arco D, Schamberger B et al. Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study. Fortschr Röntgenstr 2016; 188: 470 - 478. © Georg Thieme Verlag KG Stuttgart · New York.

Modeling and Control of Needles with Torsional Friction

PubMed Central

Reed, Kyle B.; Okamura, Allison M.; Cowan, Noah J.

2010-01-01

A flexible needle can be accurately steered by robotically controlling the bevel tip orientation as the needle is inserted into tissue. Friction between the long, flexible needle shaft and the tissue can cause a significant discrepancy between the orientation of the needle tip and the orientation of the base where the needle angle is controlled. Our experiments show that several common phantom tissues used in needle steering experiments impart substantial friction forces to the needle shaft, resulting in a lag of over 45° for a 10 cm insertion depth in some phantoms; clinical studies report torques large enough to cause similar errors during needle insertions. Such angle discrepancies will result in poor performance or failure of path planners and image-guided controllers, since the needles used in percutaneous procedures are too small for state-of-the-art imaging to accurately measure the tip angle. To compensate for the angle discrepancy, we develop an estimator using a mechanics-based model of the rotational dynamics of a needle being inserted into tissue. Compared to controllers that assume a rigid needle in a frictionless environment, our estimator-based controller improves the tip angle convergence time by nearly 50% and reduces the path deviation of the needle by 70%. PMID:19695979

Accelerated Learning Options: Moving the Needle on Access and Success. A Study of State and Institutional Policies and Practices

ERIC Educational Resources Information Center

Western Interstate Commission for Higher Education, 2006

2006-01-01

This document was designed to inform members of the policy, education, and research communities about existing state and institutional policies and practices associated with four accelerated learning programs: Advanced Placement (AP), dual/concurrent enrollment, the International Baccalaureate (IB) Diploma Program, and Tech-Prep. This effort was…

Peripherally Inserted Central Catheter Placement with the Sonic Flashlight: Initial Clinical Trial by Nurses

PubMed Central

Wang, David; Amesur, Nikhil; Shukla, Gaurav; Bayless, Angela; Weiser, David; Scharl, Adam; Mockel, Derek; Banks, Christopher; Mandella, Bernadette; Klatzky, Roberta; Stetten, George

2010-01-01

Objective We describe a case series comprising the first clinical trial by intravenous (IV) team nurses using the Sonic Flashlight for ultrasound guidance of peripherally inserted central catheter (PICC) placement. Methods Two IV team nurses with more than 10 years experience placing PICCs and from 3–6 years experience with ultrasound (US) attempted to place PICCs under US guidance in patients requiring long-term IV access. One of two methods of US guidance was used: conventional ultrasound (CUS) (60 patients) or a new device called the Sonic Flashlight (SF) (44 patients). The number of needle punctures required to gain IV access was recorded for each subject. Results In both methods, 87% of the cases resulted in successful venous access on the first attempt. The average number of needle sticks per patient was 1.18 for SF-guided procedures, as compared to 1.20 for CUS-guided procedures. No significant difference was found in the distribution of the number of attempts between the two methods. Anecdotal comments by the nurses indicated the comparative ease of use of the SF display, although relatively small scale of the SF image compared to the CUS image was also noted. Conclusions We have shown that the Sonic Flashlight is a safe and effective device for guidance of PICC placement in the hands of experienced IV team nurses. The advantage of placing the ultrasound image at its actual location must be balanced against the relatively small scale of the SF image. PMID:19389904

Comparison of pain perception during miniscrew placement in orthodontic patients with a visual analog scale survey between compound topical and needle-injected anesthetics: A crossover, prospective, randomized clinical trial.

PubMed

Lamberton, Jordan A; Oesterle, Larry J; Shellhart, W Craig; Newman, Sheldon M; Harrell, Ricky E; Tilliss, Terri; Singh, Neha; Carey, Clifton M

2016-01-01

The use of a compound topical anesthetic (CTA) instead of an injection of a local anesthetic for placing miniscrew implants offers advantages to both the clinician and the patient. The purpose of this crossover, prospective, randomized clinical trial was to compare the clinical effectiveness of a CTA with that of a needle injection of local anesthetic for miniscrew placement. Twenty-four orthodontic patients in a university clinic were recruited; they required bilateral buccal miniscrews for orthodontic anchorage. Eligibility criteria included healthy patients with no special needs; over 8 years of age and 25 pounds; not taking sulfonamides, monoamine oxidase inhibitors, tricyclic antidepressants, or phenothiazines; and not allergic to ester-type local anesthetics or any of the other materials used in the study. A computer generated a randomization list. The allocation was randomized by anesthetic protocol and side of the mouth, and was restricted to achieve balance by treatment and side of the mouth. No allocation concealment was applied. Associated with each randomized number was the subjects' assignment into 1 of 4 groups divided by the side of first miniscrew placement and the type of anesthetic. Blinding was done only for data analysis because of clinical limitations. Each patient received a CTA on one side and an injection of anesthetic on the other before miniscrew placement in a crossover study design. The outcome was assessed by measuring pain levels with a 100-mm visual analog scale at 5 time points. Anesthetic failures occurred when the miniscrew could not be fully comfortably placed with a given anesthetic. Data were organized by visual analog scale time points, and descriptive statistics were calculated. A factorial repeated-measures analysis of variance was used to determine any differences. Twenty-seven patients were assessed for eligibility, and 24 agreed to participate in the study. Patients did not distinguish any differences in pain between the application of the CTA and the injection before or during anesthetic placement, but they experienced more pain with the CTA during miniscrew placement. The mean difference for the entire procedure between the 2 anesthesia types was 24.6 units, and the 95% confidence interval was 18.8 to 30.4, a statistically significant finding (P = 0.0002). The CTA was still viewed as more painful 1 month after the procedures. Significantly more anesthetic failures occurred with the CTA (41.6%) than with the injection (0%). No serious harm was observed in any patient; when significant pain was observed with the CTA, a needle injection of local anesthetic was administered. CTAs provided less predictable, often inadequate, and less comfortable anesthesia than an injection of a local anesthetic for managing patient discomfort during miniscrew placement in buccal sites. This trial was not registered. The protocol was determined and approved by the research committee and institutional review board before the trial. No external funding was used other than the donation of the miniscrews from Rocky Mountain Orthodontics, and no conflict of interest was declared. Copyright © 2016. Published by Elsevier Inc.

Package Design Affects Accuracy Recognition for Medications.

PubMed

Endestad, Tor; Wortinger, Laura A; Madsen, Steinar; Hortemo, Sigurd

2016-12-01

Our aim was to test if highlighting and placement of substance name on medication package have the potential to reduce patient errors. An unintentional overdose of medication is a large health issue that might be linked to medication package design. In two experiments, placement, background color, and the active ingredient of generic medication packages were manipulated according to best human factors guidelines to reduce causes of labeling-related patient errors. In two experiments, we compared the original packaging with packages where we varied placement of the name, dose, and background of the active ingredient. Age-relevant differences and the effect of color on medication recognition error were tested. In Experiment 1, 59 volunteers (30 elderly and 29 young students), participated. In Experiment 2, 25 volunteers participated. The most common error was the inability to identify that two different packages contained the same active ingredient (young, 41%, and elderly, 68%). This kind of error decreased with the redesigned packages (young, 8%, and elderly, 16%). Confusion errors related to color design were reduced by two thirds in the redesigned packages compared with original generic medications. Prominent placement of substance name and dose with a band of high-contrast color support recognition of the active substance in medications. A simple modification including highlighting and placing the name of the active ingredient in the upper right-hand corner of the package helps users realize that two different packages can contain the same active substance, thus reducing the risk of inadvertent medication overdose. © 2016, Human Factors and Ergonomics Society.

Package Design Affects Accuracy Recognition for Medications

PubMed Central

Endestad, Tor; Wortinger, Laura A.; Madsen, Steinar; Hortemo, Sigurd

2016-01-01

Objective: Our aim was to test if highlighting and placement of substance name on medication package have the potential to reduce patient errors. Background: An unintentional overdose of medication is a large health issue that might be linked to medication package design. In two experiments, placement, background color, and the active ingredient of generic medication packages were manipulated according to best human factors guidelines to reduce causes of labeling-related patient errors. Method: In two experiments, we compared the original packaging with packages where we varied placement of the name, dose, and background of the active ingredient. Age-relevant differences and the effect of color on medication recognition error were tested. In Experiment 1, 59 volunteers (30 elderly and 29 young students), participated. In Experiment 2, 25 volunteers participated. Results: The most common error was the inability to identify that two different packages contained the same active ingredient (young, 41%, and elderly, 68%). This kind of error decreased with the redesigned packages (young, 8%, and elderly, 16%). Confusion errors related to color design were reduced by two thirds in the redesigned packages compared with original generic medications. Conclusion: Prominent placement of substance name and dose with a band of high-contrast color support recognition of the active substance in medications. Application: A simple modification including highlighting and placing the name of the active ingredient in the upper right-hand corner of the package helps users realize that two different packages can contain the same active substance, thus reducing the risk of inadvertent medication overdose. PMID:27591209

A navigation system for percutaneous needle interventions based on PET/CT images: design, workflow and error analysis of soft tissue and bone punctures.

PubMed

Oliveira-Santos, Thiago; Klaeser, Bernd; Weitzel, Thilo; Krause, Thomas; Nolte, Lutz-Peter; Peterhans, Matthias; Weber, Stefan

2011-01-01

Percutaneous needle intervention based on PET/CT images is effective, but exposes the patient to unnecessary radiation due to the increased number of CT scans required. Computer assisted intervention can reduce the number of scans, but requires handling, matching and visualization of two different datasets. While one dataset is used for target definition according to metabolism, the other is used for instrument guidance according to anatomical structures. No navigation systems capable of handling such data and performing PET/CT image-based procedures while following clinically approved protocols for oncologic percutaneous interventions are available. The need for such systems is emphasized in scenarios where the target can be located in different types of tissue such as bone and soft tissue. These two tissues require different clinical protocols for puncturing and may therefore give rise to different problems during the navigated intervention. Studies comparing the performance of navigated needle interventions targeting lesions located in these two types of tissue are not often found in the literature. Hence, this paper presents an optical navigation system for percutaneous needle interventions based on PET/CT images. The system provides viewers for guiding the physician to the target with real-time visualization of PET/CT datasets, and is able to handle targets located in both bone and soft tissue. The navigation system and the required clinical workflow were designed taking into consideration clinical protocols and requirements, and the system is thus operable by a single person, even during transition to the sterile phase. Both the system and the workflow were evaluated in an initial set of experiments simulating 41 lesions (23 located in bone tissue and 18 in soft tissue) in swine cadavers. We also measured and decomposed the overall system error into distinct error sources, which allowed for the identification of particularities involved in the process as well as highlighting the differences between bone and soft tissue punctures. An overall average error of 4.23 mm and 3.07 mm for bone and soft tissue punctures, respectively, demonstrated the feasibility of using this system for such interventions. The proposed system workflow was shown to be effective in separating the preparation from the sterile phase, as well as in keeping the system manageable by a single operator. Among the distinct sources of error, the user error based on the system accuracy (defined as the distance from the planned target to the actual needle tip) appeared to be the most significant. Bone punctures showed higher user error, whereas soft tissue punctures showed higher tissue deformation error.

Design of an Optically Controlled MR-Compatible Active Needle

PubMed Central

Ryu, Seok Chang; Quek, Zhan Fan; Koh, Je-Sung; Renaud, Pierre; Black, Richard J.; Moslehi, Behzad; Daniel, Bruce L.; Cho, Kyu-Jin; Cutkosky, Mark R.

2015-01-01

An active needle is proposed for the development of magnetic resonance imaging (MRI)-guided percutaneous procedures. The needle uses a low-transition-temperature shape memory alloy (LT SMA) wire actuator to produce bending in the distal section of the needle. Actuation is achieved with internal optical heating using laser light transported via optical fibers and side coupled to the LT SMA. A prototype, with a size equivalent to a standard 16-gauge biopsy needle, exhibits significant bending, with a tip deflection of more than 14° in air and 5° in hard tissue. A single-ended optical sensor with a gold-coated tip is developed to measure the curvature independently of temperature. The experimental results in tissue phantoms show that human tissue causes fast heat dissipation from the wire actuator; however, the active needle can compensate for typical targeting errors during prostate biopsy. PMID:26512231

Development of a virtual reality haptic Veress needle insertion simulator for surgical skills training.

PubMed

Okrainec, A; Farcas, M; Henao, O; Choy, I; Green, J; Fotoohi, M; Leslie, R; Wight, D; Karam, P; Gonzalez, N; Apkarian, J

2009-01-01

The Veress needle is the most commonly used technique for creating the pneumoperitoneum at the start of a laparoscopic surgical procedure. Inserting the Veress needle correctly is crucial since errors can cause significant harm to patients. Unfortunately, this technique can be difficult to teach since surgeons rely heavily on tactile feedback while advancing the needle through the various layers of the abdominal wall. This critical step in laparoscopy, therefore, can be challenging for novice trainees to learn without adequate opportunities to practice in a safe environment with no risk of injury to patients. To address this issue, we have successfully developed a prototype of a virtual reality haptic needle insertion simulator using the tactile feedback of 22 surgeons to set realistic haptic parameters. A survey of these surgeons concluded that our device appeared and felt realistic, and could potentially be a useful tool for teaching the proper technique of Veress needle insertion.

Patterning control strategies for minimum edge placement error in logic devices

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Hanna, Michael; Slachter, Bram; Tel, Wim; Kubis, Michael; Maslow, Mark; Spence, Chris; Timoshkov, Vadim

2017-03-01

In this paper we discuss the edge placement error (EPE) for multi-patterning semiconductor manufacturing. In a multi-patterning scheme the creation of the final pattern is the result of a sequence of lithography and etching steps, and consequently the contour of the final pattern contains error sources of the different process steps. We describe the fidelity of the final pattern in terms of EPE, which is defined as the relative displacement of the edges of two features from their intended target position. We discuss our holistic patterning optimization approach to understand and minimize the EPE of the final pattern. As an experimental test vehicle we use the 7-nm logic device patterning process flow as developed by IMEC. This patterning process is based on Self-Aligned-Quadruple-Patterning (SAQP) using ArF lithography, combined with line cut exposures using EUV lithography. The computational metrology method to determine EPE is explained. It will be shown that ArF to EUV overlay, CDU from the individual process steps, and local CD and placement of the individual pattern features, are the important contributors. Based on the error budget, we developed an optimization strategy for each individual step and for the final pattern. Solutions include overlay and CD metrology based on angle resolved scatterometry, scanner actuator control to enable high order overlay corrections and computational lithography optimization to minimize imaging induced pattern placement errors of devices and metrology targets.

Development and Evaluation of a Novel Curved Biopsy Device for CT-Guided Biopsy of Lesions Unreachable Using Standard Straight Needle Trajectories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulze-Hagen, Maximilian Franz, E-mail: mschulze@ukaachen.de; Pfeffer, Jochen; Zimmermann, Markus

PurposeTo evaluate the feasibility of a novel curved CT-guided biopsy needle prototype with shape memory to access otherwise not accessible biopsy targets.Methods and MaterialsA biopsy needle curved by 90° with specific radius was designed. It was manufactured using nitinol to acquire shape memory, encased in a straight guiding trocar to be driven out for access of otherwise inaccessible targets. Fifty CT-guided punctures were conducted in a biopsy phantom and 10 CT-guided punctures in a swine corpse. Biposies from porcine liver and muscle tissue were separately gained using the biopsy device, and histological examination was performed subsequently.ResultsMean time for placement ofmore » the trocar and deployment of the inner biopsy needle was ~205 ± 69 and ~93 ± 58 s, respectively, with a mean of ~4.5 ± 1.3 steps to reach adequate biopsy position. Mean distance from the tip of the needle to the target was ~0.7 ± 0.8 mm. CT-guided punctures in the swine corpse took relatively longer and required more biopsy steps (~574 ± 107 and ~380 ± 148 s, 8 ± 2.6 steps). Histology demonstrated appropriate tissue samples in nine out of ten cases (90%).ConclusionsTargets that were otherwise inaccessible via standard straight needle trajectories could be successfully reached with the curved biopsy needle prototype. Shape memory and preformed size with specific radius of the curved needle simplify the target accessibility with a low risk of injuring adjacent structures.« less

PERTINENT DRY NEEDLING CONSIDERATIONS FOR MINIMIZING ADVERSE EFFECTS – PART ONE

PubMed Central

Halle, Rob J.

2016-01-01

ABSTRACT Background Dry needling is an evidence-based treatment technique that is accepted and used by physical therapists in the United States. This treatment approach focuses on releasing or inactivating muscular trigger points to decrease pain, reduce muscle tension, and assist patients with an accelerated return to active rehabilitation. Issue While commonly used, the technique has some patient risk and value of the treatment should be based on benefit compared to the potential risk. Adverse effects (AEs) with dry needling can be mild or severe, with overall incidence rates varying from zero to rates of approximately 10 percent. While mild AEs are the rule, any procedure that involves a needle insertion has the potential for an AE, with select regions and the underlying anatomy increasing the risk. Known significant AEs from small diameter needle insertion include pneumothorax, cardiac tamponade, hematoma, infection, central nervous system injury, and other complications. Purpose/Objective Underlying anatomy across individuals has variability, requiring an in-depth knowledge of anatomy prior to any needle placement. This commentary is an overview of pertinent anatomy in the region of the thorax, with a ‘part two’ that addresses the abdomen, pelvis, back, vasovagal response, informed consent and other pertinent issues. The purpose of the commentary is to minimize the risk of a dry needling AE. Conclusions/Implications Dry needling is an effective adjunct treatment procedure that is within the recognized scope of physical therapy practice. Physical therapy education and training provides practitioners with the anatomy, basic sciences, and clinical foundation to use this intervention safely and effectively. A safe and evidenced-based implementation of the procedure is based on a thorough understanding of the underlying anatomy and the potential risks, with risks coordinated with patients via informed consent. Levels of Evidence Level 5 PMID:27525188

Electron Microscopy of Dural and Arachnoid Disruptions After Subarachnoid Block.

PubMed

Reina, Miguel Angel; Puigdellívol-Sánchez, Anna; Gatt, Stephen P; De Andrés, José; Prats-Galino, Alberto; van Zundert, André

It has been customary to attribute postdural puncture headache (PDPH) incidence and severity to size and nature of the dural hole produced during major neuraxial blockade or diagnostic dural puncture. Needle orientation in relation to the direction of dural fibers was thought to be of importance because of the propensity for horizontal bevel placement to cause cutting rather than splitting of the dural fibers. In vitro punctures of stringently quality-controlled human dural sac specimens were obtained with 27-gauge (27G) Whitacre needle (n = 33), with 29G Quincke used parallel to the spinal axis (n = 30), and with 29G Quincke in perpendicular approach (n = 40). The samples were studied with a scanning electron microscope, and the perimeter, appearance, and area (%) of the lesion were calculated. When using small 27G to 29G needles, neither needle tip characteristics nor needle orientation had a substantial bearing on the damage to dural fibers in the dural lesion. Of ultimate importance was the characteristic and size of the hole in the arachnoid. Arachnoid layer lesions produced by different types of spinal needles were not markedly different. Accepted theories of the etiology of PDPH need to be revised. This article marks the first time that arachnoid layer damage has been quantified. Dural fibers tend to have sufficient "memory" to close back the hole created by a spinal needle, whereas arachnoid has diminished capacity to do so. The pathogenesis of PDPH and its resolution algorithm are a far more complex process that involves many more "stages" of development than hitherto imagined.

The effect of body position on the 'hanging drop' method for identifying the extradural space in anaesthetized dogs.

PubMed

Naganobu, Kiyokazu; Hagio, Mitsuyoshi

2007-01-01

To assess the accuracy of the 'hanging drop method' for identifying the extradural space in anaesthetized dogs positioned in sternal or lateral recumbency. Prospective randomized-experimental study. Seventeen clinically healthy adult dogs, 10 females and seven males weighing 8.4-26.2 kg. Dogs were positioned in either sternal (n = 8) or lateral (n = 9) recumbency under general anaesthesia. A 20 SWG spinal needle pre-filled with 0.9% saline was advanced through the skin into the lumbosacral extradural space and the response of the saline drop recorded, i.e. whether it: 1) was aspirated from the hub into the needle; 2) remained within the hub, or 3) moved synchronously with i) spontaneous respiration, ii) heart beat or iii) manual lung inflation. The position of the needle tip was ultimately determined by positive contrast radiography. One dog positioned in lateral recumbency was excluded from the study because bleeding occurred from the needle hub. Saline was aspirated into the needle in seven of eight dogs held in sternal recumbency but in none of the dogs positioned in lateral recumbency. Accurate needle tip placement in the extradural space was confirmed by positive contrast radiography in all dogs. The 'hanging drop' method, when performed with a spinal needle, appears to be a useful technique for identifying the location of the extradural space in anaesthetized medium-sized dogs positioned in sternal, but not in lateral recumbency. The technique may yield 'false negative' results when performed in dogs positioned in sternal recumbency.

Pattern placement errors: application of in-situ interferometer-determined Zernike coefficients in determining printed image deviations

NASA Astrophysics Data System (ADS)

Roberts, William R.; Gould, Christopher J.; Smith, Adlai H.; Rebitz, Ken

2000-08-01

Several ideas have recently been presented which attempt to measure and predict lens aberrations for new low k1 imaging systems. Abbreviated sets of Zernike coefficients have been produced and used to predict Across Chip Linewidth Variation. Empirical use of the wavefront aberrations can now be used in commercially available lithography simulators to predict pattern distortion and placement errors. Measurement and Determination of Zernike coefficients has been a significant effort of many. However the use of this data has generally been limited to matching lenses or picking best fit lense pairs. We will use wavefront aberration data collected using the Litel InspecStep in-situ Interferometer as input data for Prolith/3D to model and predict pattern placement errors and intrafield overlay variation. Experiment data will be collected and compared to the simulated predictions.

Quick foot placement adjustments during gait are less accurate in individuals with focal cerebellar lesions.

PubMed

Hoogkamer, Wouter; Potocanac, Zrinka; Van Calenbergh, Frank; Duysens, Jacques

2017-10-01

Online gait corrections are frequently used to restore gait stability and prevent falling. They require shorter response times than voluntary movements which suggests that subcortical pathways contribute to the execution of online gait corrections. To evaluate the potential role of the cerebellum in these pathways we tested the hypotheses that online gait corrections would be less accurate in individuals with focal cerebellar damage than in neurologically intact controls and that this difference would be more pronounced for shorter available response times and for short step gait corrections. We projected virtual stepping stones on an instrumented treadmill while some of the approaching stepping stones were shifted forward or backward, requiring participants to adjust their foot placement. Varying the timing of those shifts allowed us to address the effect of available response time on foot placement error. In agreement with our hypothesis, individuals with focal cerebellar lesions were less accurate in adjusting their foot placement in reaction to suddenly shifted stepping stones than neurologically intact controls. However, the cerebellar lesion group's foot placement error did not increase more with decreasing available response distance or for short step versus long step adjustments compared to the control group. Furthermore, foot placement error for the non-shifting stepping stones was also larger in the cerebellar lesion group as compared to the control group. Consequently, the reduced ability to accurately adjust foot placement during walking in individuals with focal cerebellar lesions appears to be a general movement control deficit, which could contribute to increased fall risk. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-axis view for ultrasound-guided central venous catheter placement via the internal jugular vein.

PubMed

Mahan, Angel F; McEvoy, Matthew D; Gravenstein, Nikolaus

2016-04-01

In modern practice, real-time ultrasound guidance is commonly employed for the placement of internal jugular vein catheters. With a new tool, such as ultrasound, comes the opportunity to refine and further optimize the ultrasound view during jugular vein catheterization. We describe jugular vein access techniques and use the long-axis view as an alternative to the commonly employed short-axis cross-section view for internal jugular vein access and cannulation. The long-axis ultrasound-guided internal jugular vein approach for internal jugular vein cannulation is a useful alternative technique that can provide better needle tip and guidewire visualization than the more traditional short-axis ultrasound view.

Investigation of tissue cellularity at the tip of the core biopsy needle with optical coherence tomography.

PubMed

Iftimia, Nicusor; Park, Jesung; Maguluri, Gopi; Krishnamurthy, Savitri; McWatters, Amanda; Sabir, Sharjeel H

2018-02-01

We report the development and the pre-clinical testing of a new technology based on optical coherence tomography (OCT) for investigating tissue composition at the tip of the core biopsy needle. While ultrasound, computed tomography, and magnetic resonance imaging are routinely used to guide needle placement within a tumor, they still do not provide the resolution needed to investigate tissue cellularity (ratio between viable tumor and benign stroma) at the needle tip prior to taking a biopsy core. High resolution OCT imaging, however, can be used to investigate tissue morphology at the micron scale, and thus to determine if the biopsy core would likely have the expected composition. Therefore, we implemented this capability within a custom-made biopsy gun and evaluated its capability for a correct estimation of tumor tissue cellularity. A pilot study on a rabbit model of soft tissue cancer has shown the capability of this technique to provide correct evaluation of tumor tissue cellularity in over 85% of the cases. These initial results indicate the potential benefit of the OCT-based approach for improving the success of the core biopsy procedures.

Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces

PubMed Central

Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2015-01-01

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165

Ultrasound-Guided Cryoanalgesia of Peripheral Nerve Lesions.

PubMed

Djebbar, Sahlya; Rossi, Ignacio M; Adler, Ronald S

2016-11-01

The real-time nature of ultrasound makes it ideally suited to provide guidance for a variety of musculoskeletal interventional procedures involving peripheral nerves. Continuous observation of the needle ensures proper placement and allows continuous monitoring when performing localized ablative therapy and therefore more accurate positioning of a cryoprobe, use of smaller needles, as well as access to small structures. We describe our experience performing cryoablative procedures. Patients undergoing cryoneurolysis have largely reported varying degrees of long-term pain relief and improvement in function; no serious complications have yet been identified. Ultrasound-guided cryoneurolysis can provide a useful, safe alternative to other ablative techniques to achieve long-term analgesia from painful peripheral nerve lesions. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Comparison of a GPS needle-tracking system, multiplanar imaging and 2D imaging for real-time ultrasound-guided epidural anaesthesia: A randomized, comparative, observer-blinded study on phantoms.

PubMed

Menacé, Cécilia; Choquet, Olivier; Abbal, Bertrand; Bringuier, Sophie; Capdevila, Xavier

2017-04-01

The real-time ultrasound-guided paramedian sagittal oblique approach for neuraxial blockade is technically demanding. Innovative technologies have been developed to improve nerve identification and the accuracy of needle placement. The aim of this study was to evaluate three types of ultrasound scans during ultrasound-guided epidural lumbar punctures in a spine phantom. Eleven sets of 20 ultrasound-guided epidural punctures were performed with 2D, GPS, and multiplanar ultrasound machines (660 punctures) on a spine phantom using an in-plane approach. For all punctures, execution time, number of attempts, bone contacts, and needle redirections were noted by an independent physician. Operator comfort and visibility of the needle (tip and shaft) were measured using a numerical scale. The use of GPS significantly decreased the number of punctures, needle repositionings, and bone contacts. Comfort of the physician was also significantly improved with the GPS system compared with the 2D and multiplanar systems. With the multiplanar system, the procedure was not facilitated and execution time was longer compared with 2D imaging after Bonferroni correction but interaction between the type of ultrasound system and mean execution time was not significant in a linear mixed model. There were no significant differences regarding needle tip and shaft visibility between the systems. Multiplanar and GPS needle-tracking systems do not reduce execution time compared with 2D imaging using a real-time ultrasound-guided paramedian sagittal oblique approach in spine phantoms. The GPS needle-tracking system can improve performance in terms of operator comfort, the number of attempts, needle redirections and bone contacts. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

A modified efficient purse-string stapling technique (mEST) that uses a new metal rod for intracorporeal esophagojejunostomy in laparoscopic total gastrectomy

PubMed Central

Moon, Jeong-Ho; Yamamoto, Kazuyoshi; Yanagimoto, Yoshitomo; Sugimura, Keijirou; Miyata, Hiroshi; Yano, Masahiko; Sakon, Masato

2017-01-01

Intracorporeal esophagojejunostomy after laparoscopic total gastrectomy is technically difficult because this procedure should be performed in a narrow surgical field in the upper abdomen even when completely laparoscopic approaches are used. The placement of the anvil of a circular stapling device into the esophagus and connection the instrument to the anvil are extremely difficult steps in this surgery. Therefore, we developed a simple technique for intracorporeal esophagojejunostomy using hemi-double stapling technique; we named this technique the efficient purse-string stapling technique (EST). More recently, we have developed a modified EST (mEST) that utilizes a new stainless steel anvil rod instead of a plastic rod. Relative to the plastic rod, the steel rod is reusable and shorter; thus, it was easier to perform anvil placement into the esophagus with the steel rod. Anvil preparation for mEST: a stainless steel rod is attached to the shaft of the anvil, and the needle and thread are sutured to the tip of the rod. After complete insertion of the anvil into the esophageal cavity, the needle and thread are used to penetrate the anterior esophageal wall, and the esophagus is then clamped using a linear stapler just distal to the site penetrated by the thread. The linear stapler is fired, and anvil placement in the esophagus is simultaneously accomplished. After the rod is removed from the anvil, the instrument is intracorporeally connected to the anvil and then fired to complete the gastrojejunostomy. This technique is simple and facilitates intracorporeal reconstruction procedures in laparoscopic total gastrectomy. PMID:28815221

A Prototype Educational Model for Hepatobiliary Interventions: Unveiling the Role of Graphic Designers in Medical 3D Printing.

PubMed

Javan, Ramin; Zeman, Merissa N

2018-02-01

In the context of medical three-dimensional (3D) printing, in addition to 3D reconstruction from cross-sectional imaging, graphic design plays a role in developing and/or enhancing 3D-printed models. A custom prototype modular 3D model of the liver was graphically designed depicting segmental anatomy of the parenchyma containing color-coded hepatic vasculature and biliary tree. Subsequently, 3D printing was performed using transparent resin for the surface of the liver and polyamide material to develop hollow internal structures that allow for passage of catheters and wires. A number of concepts were incorporated into the model. A representative mass with surrounding feeding arterial supply was embedded to demonstrate tumor embolization. A straight narrow hollow tract connecting the mass to the surface of the liver, displaying the path of a biopsy device's needle, and the concept of needle "throw" length was designed. A connection between the middle hepatic and right portal veins was created to demonstrate transjugular intrahepatic portosystemic shunt (TIPS) placement. A hollow amorphous structure representing an abscess was created to allow the demonstration of drainage catheter placement with the formation of pigtail tip. Percutaneous biliary drain and cholecystostomy tube placement were also represented. The skills of graphic designers may be utilized in creating highly customized 3D-printed models. A model was developed for the demonstration and simulation of multiple hepatobiliary interventions, for training purposes, patient counseling and consenting, and as a prototype for future development of a functioning interventional phantom.

Diagnostic Ability of Percutaneous Needle Biopsy Immediately After Radiofrequency Ablation for Malignant Lung Tumors: An Initial Experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasegawa, Takaaki, E-mail: t-hasegawa@aichi-cc.jp; Kondo, Chiaki; Sato, Yozo

PurposeTo evaluate the safety and diagnostic ability of percutaneous needle biopsy performed immediately after lung radiofrequency ablation (RFA).Materials and MethodsFrom May 2013 to April 2014, percutaneous needle biopsy was performed immediately after RFA for 3 patients (2 men and 1 woman, aged 57–76 years) who had lung tumors measuring 1.3–2.6 cm in diameter. All patients had prior history of malignancy, and all tumors were radiologically diagnosed as malignant. Obtained specimens were pathologically classified using standard hematoxylin and eosin staining.ResultsWe completed three planned sessions of RFA followed by percutaneous needle biopsy, all of which obtained tumor tissue that could be pathologically diagnosed. Twomore » tumors were metastatic from renal clear cell carcinoma and rectal adenocarcinoma, respectively; one tumor was primary lung adenocarcinoma. There was no death or major complication related to the procedures. Although pneumothorax occurred in two patients, these resolved without the need for aspiration or chest tube placement. Tumor seeding was not observed, but 21 months after the procedure, one case developed local tumor progression that was treated by additional RFA.ConclusionPathologic diagnosis was possible by needle biopsy immediately after RFA for lung tumors. This technique may reduce the risks and efforts of performing biopsy and RFA on separate occasions.« less

Estimating needle tip deflection in biological tissue from a single transverse ultrasound image: application to brachytherapy.

PubMed

Rossa, Carlos; Sloboda, Ron; Usmani, Nawaid; Tavakoli, Mahdi

2016-07-01

This paper proposes a method to predict the deflection of a flexible needle inserted into soft tissue based on the observation of deflection at a single point along the needle shaft. We model the needle-tissue as a discretized structure composed of several virtual, weightless, rigid links connected by virtual helical springs whose stiffness coefficient is found using a pattern search algorithm that only requires the force applied at the needle tip during insertion and the needle deflection measured at an arbitrary insertion depth. Needle tip deflections can then be predicted for different insertion depths. Verification of the proposed method in synthetic and biological tissue shows a deflection estimation error of [Formula: see text]2 mm for images acquired at 35 % or more of the maximum insertion depth, and decreases to 1 mm for images acquired closer to the final insertion depth. We also demonstrate the utility of the model for prostate brachytherapy, where in vivo needle deflection measurements obtained during early stages of insertion are used to predict the needle deflection further along the insertion process. The method can predict needle deflection based on the observation of deflection at a single point. The ultrasound probe can be maintained at the same position during insertion of the needle, which avoids complications of tissue deformation caused by the motion of the ultrasound probe.

Transversely polarized sub-diffraction optical needle with ultra-long depth of focus

NASA Astrophysics Data System (ADS)

Guan, Jian; Lin, Jie; Chen, Chen; Ma, Yuan; Tan, Jiubin; Jin, Peng

2017-12-01

We generated purely transversely polarized sub-diffraction optical needles with ultra-long depth of focus (DOF) by focusing azimuthally polarized (AP) beams that were modulated by a vortex 0-2 π phase plate and binary phase diffraction optical elements (DOEs). The concentric belts' radii of the DOEs were optimized by a hybrid genetic particle swarm optimization (HGPSO) algorithm. For the focusing system with the numerical aperture (NA) of 0.95, an optical needle with the full width at half maximum (FWHM) of 0.40 λ and the DOF of 6.23 λ was generated. Similar optical needles were also generated by binary phase DOEs with different belts. The results demonstrated that the binary phase DOEs could achieve smaller FWHMs and longer DOFs simultaneously. The generated needles were circularly polarized on the z-axis and there were no longitudinally polarized components in the focal fields. The radius fabrication errors of a DOE have little effect on the optical needle produced by itself. The generated optical needles can be applied to the fields of photolithography, high-density optical data storage, microscope imaging and particle trapping.

A novel adaptive needle insertion sequencing for robotic, single needle MR-guided high-dose-rate prostate brachytherapy

NASA Astrophysics Data System (ADS)

Borot de Battisti, M.; de Senneville, B. Denis; Hautvast, G.; Binnekamp, D.; Lagendijk, J. J. W.; Maenhout, M.; Moerland, M. A.

2017-05-01

MR-guided high-dose-rate (HDR) brachytherapy has gained increasing interest as a treatment for patients with localized prostate cancer because of the superior value of MRI for tumor and surrounding tissues localization. To enable needle insertion into the prostate with the patient in the MR bore, a single needle MR-compatible robotic system involving needle-by-needle dose delivery has been developed at our institution. Throughout the intervention, dose delivery may be impaired by: (1) sub-optimal needle positioning caused by e.g. needle bending, (2) intra-operative internal organ motion such as prostate rotations or swelling, or intra-procedural rectum or bladder filling. This may result in failure to reach clinical constraints. To assess the first aforementioned challenge, a recent study from our research group demonstrated that the deposited dose may be greatly improved by real-time adaptive planning with feedback on the actual needle positioning. However, the needle insertion sequence is left to the doctor and therefore, this may result in sub-optimal dose delivery. In this manuscript, a new method is proposed to determine and update automatically the needle insertion sequence. This strategy is based on the determination of the most sensitive needle track. The sensitivity of a needle track is defined as its impact on the dose distribution in case of sub-optimal positioning. A stochastic criterion is thus presented to determine each needle track sensitivity based on needle insertion simulations. To assess the proposed sequencing strategy, HDR prostate brachytherapy was simulated on 11 patients with varying number of needle insertions. Sub-optimal needle positioning was simulated at each insertion (modeled by typical random angulation errors). In 91% of the scenarios, the dose distribution improved when the needle was inserted into the most compared to the least sensitive needle track. The computation time for sequencing was less than 6 s per needle track. The proposed needle insertion sequencing can therefore assist in delivering an optimal dose in HDR prostate brachytherapy.

Real-Time Estimation of 3-D Needle Shape and Deflection for MRI-Guided Interventions

PubMed Central

Park, Yong-Lae; Elayaperumal, Santhi; Daniel, Bruce; Ryu, Seok Chang; Shin, Mihye; Savall, Joan; Black, Richard J.; Moslehi, Behzad; Cutkosky, Mark R.

2015-01-01

We describe a MRI-compatible biopsy needle instrumented with optical fiber Bragg gratings for measuring bending deflections of the needle as it is inserted into tissues. During procedures, such as diagnostic biopsies and localized treatments, it is useful to track any tool deviation from the planned trajectory to minimize positioning errors and procedural complications. The goal is to display tool deflections in real time, with greater bandwidth and accuracy than when viewing the tool in MR images. A standard 18 ga × 15 cm inner needle is prepared using a fixture, and 350-μm-deep grooves are created along its length. Optical fibers are embedded in the grooves. Two sets of sensors, located at different points along the needle, provide an estimate of the bent profile, as well as temperature compensation. Tests of the needle in a water bath showed that it produced no adverse imaging artifacts when used with the MR scanner. PMID:26405428

Perception of Place of Articulation by Children with Cleft Palate and Posterior Placement.

ERIC Educational Resources Information Center

Whitehill, Tara L.; Francis, Alexander L.; Ching, Christine K-Y.

2003-01-01

A study examined if 10 children (ages 4-12) with repaired cleft palate who demonstrate posterior placement of alveolar targets differed from 10 children with cleft palate without such error patterns, and from 10 controls in the perception of alveolar targets. Children with posterior placement appeared unable to distinguish alveolar targets.…

An investigation into false-negative transthoracic fine needle aspiration and core biopsy specimens.

PubMed

Minot, Douglas M; Gilman, Elizabeth A; Aubry, Marie-Christine; Voss, Jesse S; Van Epps, Sarah G; Tuve, Delores J; Sciallis, Andrew P; Henry, Michael R; Salomao, Diva R; Lee, Peter; Carlson, Stephanie K; Clayton, Amy C

2014-12-01

Transthoracic fine needle aspiration (TFNA)/core needle biopsy (CNB) under computed tomography (CT) guidance has proved useful in the assessment of pulmonary nodules. We sought to determine the TFNA false-negative (FN) rate at our institution and identify potential causes of FN diagnoses. Medical records were reviewed from 1,043 consecutive patients who underwent CT-guided TFNA with or without CNB of lung nodules over a 5-year time period (2003-2007). Thirty-seven FN cases of "negative" TFNA/CNB with malignant outcome were identified with 36 cases available for review, of which 35 had a corresponding CNB. Cases were reviewed independently (blinded to original diagnosis) by three pathologists with 15 age- and sex-matched positive and negative controls. Diagnosis (i.e., nondiagnostic, negative or positive for malignancy, atypical or suspicious) and qualitative assessments were recorded. Consensus diagnosis was suspicious or positive in 10 (28%) of 36 TFNA cases and suspicious in 1 (3%) of 35 CNB cases, indicating potential interpretive errors. Of the 11 interpretive errors (including both suspicious and positive cases), 8 were adenocarcinomas, 1 squamous cell carcinoma, 1 metastatic renal cell carcinoma, and 1 lymphoma. The remaining 25 FN cases (69.4%) were considered sampling errors and consisted of 7 adenocarcinomas, 3 nonsmall cell carcinomas, 3 lymphomas, 2 squamous cell carcinomas, and 2 renal cell carcinomas. Interpretive and sampling error cases were more likely to abut the pleura, while histopathologically, they tended to be necrotic and air-dried. The overall FN rate in this patient cohort is 3.5% (1.1% interpretive and 2.4% sampling errors). © 2014 Wiley Periodicals, Inc.

Needle Steering in 3-D Via Rapid Replanning

PubMed Central

Patil, Sachin; Burgner, Jessica; Webster, Robert J.; Alterovitz, Ron

2014-01-01

Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. PMID:25435829

Imaging of implant needles for real-time HDR-brachytherapy prostate treatment using biplane ultrasound transducers.

PubMed

Siebert, Frank-André; Hirt, Markus; Niehoff, Peter; Kovács, György

2009-08-01

Ultrasound imaging is becoming increasingly important in prostate brachytherapy. In high-dose-rate (HDR) real-time planning procedures the definition of the implant needles is often performed by transrectal ultrasound. This article describes absolute measurements of the visibility and accuracy of manual detection of implant needle tips and compares measurement results of different biplane ultrasound systems in transversal and longitudinal (i.e., sagittal) ultrasound modes. To obtain a fixed coordinate system and stable conditions the measurements were carried out in a water tank using a dedicated marker system. Needles were manually placed in the phantom until the observer decided by the real-time ultrasound image that the zero position was reached. A comparison of three different ultrasound systems yielded an offset between 0.8 and 3.1 mm for manual detection of the needle tip in ultrasound images by one observer. The direction of the offset was discovered to be in the proximal direction, i.e., the actual needle position was located more distally compared to the ultrasound-based definition. In the second part of the study, the ultrasound anisotropy of trocar implant needles is reported. It was shown that the integrated optical density in a region of interest around the needle tip changes with needle rotation. Three peaks were observed with a phase angle of 120 degrees. Peaks appear not only in transversal but also in longitudinal ultrasound images, with a phase shift of 60 degrees. The third section of this study shows results of observer dependent influences on needle tip detection in sagittal ultrasound images considering needle rotation. These experiments were carried out using the marker system in a water tank. The needle tip was placed exactly at the position z=0 mm. It was found that different users tend to differently interpret the same ultrasound images. The needle tip was manually detected five times in the ultrasound images by three experienced observers at positions (+/- standard deviation) -0.53 +/- 0.16, -0.16 +/- 0.14, and -0.30 +/- 0.16 mm using a gain of 15 dB. The minus sign indicates that the needle tips were detected more proximally than the actual position of the needle tip. When using a gain of -15 dB the mean values of two observers resulted in -0.62 +/- 0.08 and -0.51 +/- 0.12 mm. Additionally an alternative approach to the direct needle tip definition was investigated. Two observers detected the solid part of the needle tip in sagittal images. This solid part, often named as "dead space end," is the distance between the needle tip and the beginning of the hollow part of the implant needle. The dead space end is 6.2 mm for the investigated needle type. Two users found mean values of -6.70 +/- 0.16 and -7.00 +/- 0.06 mm, respectively, for 15 dB gain and -6.90 +/- 0.09 and -7.02 +/- 0.06 mm using the -15 dB gain setting. The results show that ultrasound-based needle tip definition in sagittal viewing mode is accurate. The inter- and intraobserver errors should, however, be taken into account. A lower gain setting of the ultrasound system reduces the intraobserver error.

Optimal angle of needle insertion for fluoroscopy-guided transforaminal epidural injection of L5.

PubMed

Ra, In-Hoo; Min, Woo-Kie

2015-06-01

Unlike other sites, there is difficulty in performing TFESI at the L5-S1 level because the iliac crest is an obstacle to needle placement. The objective of this study was to identify the optimal angle of fluoroscopy for insertion and advancement of a needle during L5 TEFSI. We conducted an observational study of patients undergoing fluoroscopy-guided L5 TFESI in the prone position. A total of 80 patients (40 men and 40 women) with radiating pain of lower limbs were enrolled. During TFESI, we measured the angle at which the L5 vertebral body forms a rectangular shape and compared men and women. Then, we measured area of safe triangle in tilting angle of fluoroscopy from 15° to 35° and compared men and women. The mean cephalocaudal angle, where the vertebral body takes the shape of a rectangle, was 11.0° in men and 13.9° in women (P = 0.007). In men, the triangular area was maximal at 18.3 mm² with an oblique view angle of 25°. In women, the area was maximal at 23.6 mm² with an oblique view angle of 30°. At an oblique view angle of 30° and 35°, the area was significantly greater in women (P < 0.05). When TFESI is performed at the L5 region in the prone position, placement of fluoroscopy at a cephalocaudal angle of 11.0° and an oblique angle of 25° in men and cephalocaudal angle of 13.9° and an oblique angle of 30° in women would be most reasonable. © 2014 World Institute of Pain.

MRI-Guided Percutaneous Biopsy of Mediastinal Masses Using a Large Bore Magnet: Technical Feasibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garnon, J., E-mail: juliengarnon@gmail.com; Ramamurthy, N., E-mail: nitin-ramamurthy@hotmail.com; Caudrelier J, J., E-mail: caudjean@yahoo.fr

2016-05-15

ObjectiveTo evaluate the diagnostic accuracy and safety of magnetic resonance imaging (MRI)-guided percutaneous biopsy of mediastinal masses performed using a wide-bore high-field scanner.Materials and MethodsThis is a retrospective study of 16 consecutive patients (8 male, 8 female; mean age 74 years) who underwent MRI-guided core needle biopsy of a mediastinal mass between February 2010 and January 2014. Size and location of lesion, approach taken, time for needle placement, overall duration of procedure, and post-procedural complications were evaluated. Technical success rates and correlation with surgical pathology (where available) were assessed.ResultsTarget lesions were located in the anterior (n = 13), middle (n = 2), and posterior mediastinummore » (n = 1), respectively. Mean size was 7.2 cm (range 3.6–11 cm). Average time for needle placement was 9.4 min (range 3–18 min); average duration of entire procedure was 42 min (range 27–62 min). 2–5 core samples were obtained from each lesion (mean 2.6). Technical success rate was 100 %, with specimens successfully obtained in all 16 patients. There were no immediate complications. Histopathology revealed malignancy in 12 cases (4 of which were surgically confirmed), benign lesions in 3 cases (1 of which was false negative following surgical resection), and one inconclusive specimen (treated as inaccurate since repeat CT-guided biopsy demonstrated thymic hyperplasia). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in our study were 92.3, 100, 100, 66.7, and 87.5 %, respectively.ConclusionMRI-guided mediastinal biopsy is a safe procedure with high diagnostic accuracy, which may offer a non-ionizing alternative to CT guidance.« less

Resident accuracy of joint line palpation using ultrasound verification.

PubMed

Rho, Monica E; Chu, Samuel K; Yang, Aaron; Hameed, Farah; Lin, Cindy Yuchin; Hurh, Peter J

2014-10-01

To determine the accuracy of knee and acromioclavicular (AC) joint line palpation in Physical Medicine and Rehabilitation (PM&R) residents using ultrasound (US) verification. Cohort study. PM&R residency program at an academic institution. Twenty-four PM&R residents participating in a musculoskeletal US course (7 PGY-2, 8 PGY-3, and 9 PGY4 residents). Twenty-four PM&R residents participating in an US course were asked to palpate the AC joint and lateral joint line of the knee in a female and male model before the start of the course. Once the presumed joint line was localized, the residents were asked to tape an 18-gauge, 1.5-inch, blunt-tip needle parallel to the joint line on the overlying skin. The accuracy of needle placement over the joint line was verified using US. US verification of correct needle placement over the joint line. Overall AC joint palpation accuracy was 16.7%, and knee lateral joint line palpation accuracy was 58.3%. Based on the resident level of education, using a value of P < .05, there were no statistically significant differences in the accuracy of joint line palpation. Residents in this study demonstrate poor accuracy of AC joint and lateral knee joint line identification by palpation, using US as the criterion standard for verification. There were no statistically significant differences in the accuracy rates of joint line palpation based on resident level of education. US may be a useful tool to use to advance the current methods of teaching the physical examination in medical education. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Efficacy of a Buffered 4% Lidocaine Formulation for Incision and Drainage: A Prospective, Randomized, Double-blind Study.

PubMed

Harreld, Taryn Kratz; Fowler, Sara; Drum, Melissa; Reader, Al; Nusstein, John; Beck, Mike

2015-10-01

Incision and drainage of symptomatic emergency patients with facial swelling is painful even after local anesthetics are administered. The purpose of this prospective, randomized, double-blind study was to compare the pain of infiltration and the pain of an incision and drainage procedure of a buffered versus a nonbuffered 4% lidocaine formulation in symptomatic emergency patients presenting with a diagnosis of pulpal necrosis, associated periapical area, and an acute clinical swelling. Eighty-eight emergency patients were randomly divided into 2 groups to receive 2 intraoral infiltration injections (mesial and distal to the swelling) of either 4% lidocaine with 1:100,000 epinephrine buffered with 0.18 mL 8.4% sodium bicarbonate using the Onpharma (Los Gatos, CA) buffering system or 4% lidocaine with 1:100,000 epinephrine. Subjects rated the pain of needle insertion, needle placement, and solution deposition for each injection using a 170-mm visual analog scale. An incision and drainage procedure was performed, and subjects rated the pain of incision, drainage, and dissection on a 170-mm visual analog scale. No significant differences between the buffered and nonbuffered 4% lidocaine formulations were found for needle insertion, placement, and solution deposition of the infiltration injections or for the treatment phases of incision, drainage, and dissection. Buffering a 4% lidocaine formulation did not significantly decrease the pain of infiltrations or significantly decrease the pain of the incision and drainage procedure when compared with a nonbuffered 4% lidocaine formulation in symptomatic patients with a diagnosis of pulpal necrosis and associated acute swelling. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Thoracic costotransverse joint pain patterns: a study in normal volunteers.

PubMed

Young, Brian A; Gill, Howard E; Wainner, Robert S; Flynn, Timothy W

2008-10-15

Pain referral patterns of asymptomatic costotransverse joints have not been established. The objective of this study was to determine the pain referral patterns of asymptomatic costotransverse joints via provocative intra-articular injection. Eight asymptomatic male volunteers received a combined total of 21 intra-articular costotransverse joint injections. Fluoroscopic imaging was used to identify and isolate each costotransverse joint and guide placement of a 25 gauge, 2.5 inch spinal needle into the costotransverse joint. Following contrast medium injection, the quality, intensity, and distribution of the resultant pain produced were recorded. Of the 21 costotransverse joint injections, 16 (76%) were classified as being intra-articular via arthrograms taken at the time of injection, and 14 of these injections produced a pain sensation distinctly different from that of needle placement. Average pain produced was 3.3/10 on a 0-10 verbal pain scale. Pain was described generally as a deep, dull ache, and pressure sensation. Pain patterns were located superficial to the injected joint, with only the right T2 injections showing referred pain 2 segments cranially and caudally. No chest wall, upper extremity or pseudovisceral pains were reported. This study provides preliminary data of the pain referral patterns of costotransverse joints. Further research is needed to compare these findings with those elicited from symptomatic subjects.

A method for retrieving endodontic or atypical nonendodontic separated instruments from the root canal: a report of two cases.

PubMed

Monteiro, Jardel Camilo do Carmo; Kuga, Milton Carlos; Dantas, Andrea Abi Rached; Jordão-Basso, Keren Cristina Fagundes; Keine, Katia Cristina; Ruchaya, Prashant Jay; Faria, Gisele; Leonardo, Renato de Toledo

2014-11-01

This clinical report presents a new method for retrieving separated instruments from the root canal with minimally invasive procedures. The presence of separated instrument in root canal may interfere in the endodontic treatment prognosis. There are several recommended methods to retrieve separated instruments, but some are difficult in clinically practice. This study describes two cases of separated instrument removal from the root canal using a stainless-steel prepared needle associated with a K-file. Case 1 presented a fractured gutta-percha condenser within the mandibular second premolar, it was separated during incorrect intracanal medication calcium hydroxide placement. Case 2 had a fractured sewing needle within the upper central incisor that the patient used to remove food debris from the root canal. After cervical preparation, the fractured instruments were fitted inside a prepared needle and then an endodontic instrument (#25 K-file) was adapted with clockwise turning motion between the needle inner wall and the fragment. The endodontic or atypical nonendodontic separated instrument may be easily pull on of the root canal using a single and low cost device. The methods for retrieving separated instruments from root canal are difficult and destructive procedures. The present case describes a simple method to solve this problem.

The Use of Laser Guidance Reduces Fluoroscopy Time for C-Arm Cone-Beam Computed Tomography-Guided Biopsies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroes, Maarten W., E-mail: Maarten.Kroes@radboudumc.nl; Strijen, Marco J. L. van, E-mail: m.van.strijen@antoniusziekenhuis.nl; Braak, Sicco J., E-mail: sjbraak@gmail.com

2016-09-15

PurposeWhen using laser guidance for cone-beam computed tomography (CBCT)-guided needle interventions, planned needle paths are visualized to the operator without the need to switch between entry- and progress-view during needle placement. The current study assesses the effect of laser guidance during CBCT-guided biopsies on fluoroscopy and procedure times.Materials and MethodsProspective data from 15 CBCT-guided biopsies of 8–65 mm thoracic and abdominal lesions assisted by a ceiling-mounted laser guidance technique were compared to retrospective data of 36 performed CBCT-guided biopsies of lesions >20 mm using the freehand technique. Fluoroscopy time, procedure time, and number of CBCT-scans were recorded. All data are presented asmore » median (ranges).ResultsFor biopsies using the freehand technique, more fluoroscopy time was necessary to guide the needle onto the target, 165 s (83–333 s) compared to 87 s (44–190 s) for laser guidance (p < 0.001). Procedure times were shorter for freehand-guided biopsies, 24 min versus 30 min for laser guidance (p < 0.001).ConclusionThe use of laser guidance during CBCT-guided biopsies significantly reduces fluoroscopy time.« less

Intra-opeartive OCT imaging and sensing devices for clinical translation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chen, Yu

2017-02-01

Stereotactic procedures that require insertion of needle-based instruments into the brain serve important roles in a variety of neurosurgical interventions, such as biopsy, catheterization, and electrode placement. A fundamental limitation of these stereotactic procedures is that they are blind procedures in that the operator does not have real-time feedback as to what lies immediately ahead of the advancing needle. Therefore, there is a great clinical need to navigate the instrument safely and accurately to the targets. Towards that end, we developed a forwarding-imaging needle-type optical coherence tomography (OCT) probe for avoiding the hemorrhage and guiding neurosurgical interventions. The needle probe has a thin diameter of 0.7 mm. The feasibility of vessel detection and neurosurgical guidance were demonstrated on sheep brain in vivo and human brain ex vivo. In addition, we further reduced the probe size to 0.3 mm using an optical Doppler sensing (ODS) fiber probe that can integrate with microelectrode recording (MER) to detect the blood vessels lying ahead to improve the safety of this procedure. Furthermore, to overcome the field-of-view limitation of OCT probe, we developed an MRI-compatible OCT imaging probe for neurosurgery. MRI/OCT multi-scale imaging integrates micro-resolution optical imaging with wide-field MRI imaging, and has potential to further improve the targeting accuracy.

Navigation with Electromagnetic Tracking for Interventional Radiology Procedures

PubMed Central

Wood, Bradford J.; Zhang, Hui; Durrani, Amir; Glossop, Neil; Ranjan, Sohan; Lindisch, David; Levy, Eliott; Banovac, Filip; Borgert, Joern; Krueger, Sascha; Kruecker, Jochen; Viswanathan, Anand; Cleary, Kevin

2008-01-01

PURPOSE To assess the feasibility of the use of preprocedural imaging for guide wire, catheter, and needle navigation with electromagnetic tracking in phantom and animal models. MATERIALS AND METHODS An image-guided intervention software system was developed based on open-source software components. Catheters, needles, and guide wires were constructed with small position and orientation sensors in the tips. A tetrahedral-shaped weak electromagnetic field generator was placed in proximity to an abdominal vascular phantom or three pigs on the angiography table. Preprocedural computed tomographic (CT) images of the phantom or pig were loaded into custom-developed tracking, registration, navigation, and rendering software. Devices were manipulated within the phantom or pig with guidance from the previously acquired CT scan and simultaneous real-time angiography. Navigation within positron emission tomography (PET) and magnetic resonance (MR) volumetric datasets was also performed. External and endovascular fiducials were used for registration in the phantom, and registration error and tracking error were estimated. RESULTS The CT scan position of the devices within phantoms and pigs was accurately determined during angiography and biopsy procedures, with manageable error for some applications. Preprocedural CT depicted the anatomy in the region of the devices with real-time position updating and minimal registration error and tracking error (<5 mm). PET can also be used with this system to guide percutaneous biopsies to the most metabolically active region of a tumor. CONCLUSIONS Previously acquired CT, MR, or PET data can be accurately codisplayed during procedures with reconstructed imaging based on the position and orientation of catheters, guide wires, or needles. Multimodality interventions are feasible by allowing the real-time updated display of previously acquired functional or morphologic imaging during angiography, biopsy, and ablation. PMID:15802449

Vascular Access Tracking System: a Web-Based Clinical Tracking Tool for Identifying Catheter Related Blood Stream Infections in Interventional Radiology Placed Central Venous Catheters.

PubMed

Morrison, James; Kaufman, John

2016-12-01

Vascular access is invaluable in the treatment of hospitalized patients. Central venous catheters provide a durable and long-term solution while saving patients from repeated needle sticks for peripheral IVs and blood draws. The initial catheter placement procedure and long-term catheter usage place patients at risk for infection. The goal of this project was to develop a system to track and evaluate central line-associated blood stream infections related to interventional radiology placement of central venous catheters. A customized web-based clinical database was developed via open-source tools to provide a dashboard for data mining and analysis of the catheter placement and infection information. Preliminary results were gathered over a 4-month period confirming the utility of the system. The tools and methodology employed to develop the vascular access tracking system could be easily tailored to other clinical scenarios to assist in quality control and improvement programs.

Effect on neurostimulation of injectates used for perineural space expansion before placement of a stimulating catheter: normal saline versus dextrose 5% in water.

PubMed

Pham Dang, Charles; Lelong, Aurélie; Guilley, Jérôme; Nguyen, Jean Michel; Volteau, Christelle; Venet, Guillaume; Perrier, Cyril; Lejus, Corinne; Blanloeil, Yvonnick

2009-01-01

We clinically assessed the electrophysiologic effect of dextrose 5% in water (D5W) and of normal saline (NS) used for expansion of the perineural space before placing a stimulating catheter. We questioned if higher current was required with NS but not with D5W, as has been observed experimentally. This was a prospective randomized double-blind study of ASA I to II patients scheduled for total knee replacement. Patients from 2 hospitals were randomly assigned to receive unidentified injectate D5W (n = 25) or NS (n = 25). The primary outcome was the minimal intensity of stimulation (MIS) recorded before and after 2 and 5 mL of study injectates were flushed through the needle before placing a stimulating catheter for continuous femoral and sciatic nerve blocks. Secondary outcomes included, among other parameters, MIS recorded during placement of stimulating catheters. No difference between groups was found with MIS before injection. However, MIS recorded during neurostimulation via the needle in all blocks was significantly higher after 2 and 5 mL of NS than after D5W. In femoral blocks, MIS recorded during placement of catheters was higher during insertion after NS than after D5W but was not different after reaching the final site, regardless of injectate used. In sciatic blocks, MIS was not different during insertion regardless of injectate but was higher after NS than after D5W after reaching the final site. The current needed to electrostimulate the femoral or sciatic nerve was higher after injection of NS than after D5W.

Innovative Technique for the Placement of the Drainage Tube for Microendoscopic Spinal Decompression.

PubMed

Mizuno, Kentaro; Mikami, Yasuo; Hase, Hitoshi; Ikeda, Takumi; Nagae, Masateru; Tonomura, Hitoshi; Shirai, Toshiharu; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2017-02-01

A technical note and retrospective study. The objectives were to describe a new method of drainage tube placement during microendoscopic spinal decompression, and compare the positioning and fluid discharge obtained with this method and the conventional method. To prevent postoperative epidural hematoma after microendoscopic decompression, a drainage tube must be placed in a suitable location. However, the narrow operative field makes precise control of the position of the tube technically difficult. We developed a method to reliably place the tube in the desired location. We use a Deschamps aneurysm needle with a slightly curved tip, which we call a drain passer. With the microendoscope in position, the drain passer, with a silk thread passed through the eye at the needle tip, is inserted percutaneously into the endoscopic field of view. The drainage tube is passed through the loop of silk thread protruding from the inside of the tubular retractor, and the thread is pulled to the outside, guiding the end of the drainage tube into the wound. This method was used in 23 cases at 44 intervertebral levels (drain passer group), and the conventional method in 20 cases at 32 intervertebral levels (conventional group). Postoperative plain radiographs were taken, and the amount of fluid discharge at postoperative hour 24 was measured. Drainage tube positioning was favorable at 43 intervertebral levels (97.7%) in the drain passer group and 26 intervertebral levels (81.3%) in the conventional group. Mean fluid discharge was 58.4±32.2 g in the drain passer group and 38.4±23.0 g in the conventional group. Positioning was significantly better and fluid discharge was significantly greater in the drain passer group. The results indicate that this method is a useful drainage tube placement technique for preventing postoperative epidural hematoma.

Electromagnetic navigation technology for more precise electrode placement in the foramen ovale: a technical report.

PubMed

Van Buyten, Jean-Pierre; Smet, Iris; Van de Kelft, Erik

2009-07-01

Introduction. Interventional pain management techniques require precise positioning of needles or electrodes, therefore fluoroscopic control is mandatory. This imaging technique does however not visualize soft tissues such as blood vessels. Moreover, patient and physician are exposed to a considerable dose of radiation. Computed tomography (CT)-scans give a better view of soft tissues, but there use requires presence of a radiologist and has proven to be laborious and time consuming. Objectives. This study is to develop a technique using electromagnetic (EM) navigation as a guidance technique for interventional pain management, using CT and/or magnetic resonance (MRI) images uploaded on the navigation station. Methods. One of the best documented interventional procedures for the management of trigeminal neuralgia is percutaneous radiofrequency treatment of the Gasserian ganglion. EM navigation software for intracranial applications already exists. We developed a technique using a stylet with two magnetic coils suitable for EM navigation. The procedure is followed in real time on a computer screen where the patient's multislice CT-scan images and three-dimensional reconstruction of his face are uploaded. Virtual landmarks on the screen are matched with those on the patient's face, calculating the precision of the needle placement. Discussion. The experience with EM navigation acquired with the radiofrequency technique can be transferred to other interventional pain management techniques, for instance, for the placement of a neuromodulation electrode close to the Gasserian ganglion. Currently, research is ongoing to extend the software of the navigation station for spinal application, and to adapt neurostimulation hardware to the EM navigation technology. This technology will allow neuromodulation techniques to be performed without x-ray exposure for the patient and the physician, and this with the precision of CT/MR imaging guidance. © 2009 International Neuromodulation Society.

Factors affecting blood sample haemolysis: a cross-sectional study.

PubMed

Barnard, Ed B G; Potter, David L; Ayling, Ruth M; Higginson, Ian; Bailey, Andrew G; Smith, Jason E

2016-04-01

To determine the effect of blood sampling through an intravenous catheter compared with a needle in Emergency Department blood sampling. We undertook a prospective, cross-sectional study in a UK university teaching hospital Emergency Department. A convenience sample of 985 patients who required blood sampling via venepuncture was collected. A total of 844 complete sets of data were analysed. The median age was 63 years, and 57% of patients were male. The primary outcome measure was the incidence of haemolysis in blood samples obtained via a needle compared with samples obtained via an intravenous catheter. Secondary outcome measures defined the effect on sample haemolysis of the side of the patient the sample was obtained from, the anatomical location of sampling, the perceived difficulty in obtaining the sample, the order of sample tubes collected, estimated tourniquet time and bench time. Data were analysed with logistic regression, and expressed as odds ratios (95% confidence intervals; P-values). Blood samples obtained through an intravenous catheter were more likely to be haemolysed than those obtained via a needle, odds ratio 5.63 (95% confidence interval 2.49-12.73; P<0.001). Blood sampling via an intravenous catheter was significantly associated with an increase in the likelihood of sample haemolysis compared with sampling with a needle. Wherever practicable, blood samples should be obtained via a needle in preference to an intravenous catheter. Future research should include both an economic evaluation, and staff and patient satisfaction of separating blood sampling and intravenous catheter placement.

Simulation and experimental studies in needle-tissue interactions.

PubMed

Konh, Bardia; Honarvar, Mohammad; Darvish, Kurosh; Hutapea, Parsaoran

2017-08-01

This work aims to introduce a new needle insertion simulation to predict the deflection of a bevel-tip needle inside soft tissue. The development of such a model, which predicts the steering behavior of the needle during needle-tissue interactions, could improve the performance of many percutaneous needle-based procedures such as brachytherapy and thermal ablation, by means of the virtual path planning and training systems of the needle toward the target and thus reducing possible incidents of complications in clinical practices. The Arbitrary-Lagrangian-Eulerian (ALE) formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. Since both large deformation and fracture of the continuum need to be considered in this model, applying ALE method for fluid analysis was considered a suitable approach. A 150 mm long needle was used to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Three experimental cases of needle steering in a soft phantom were performed to validate the simulation. An error measurement of less than 10 % was found between the predicted deflection by the simulations and the one observed in experiments, validating our approach with reasonable accuracy. The effect of the needle diameter and its bevel tip angle on the final shape of the needle was investigated using this model. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended, as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies.

Design and analysis of a tendon-based computed tomography-compatible robot with remote center of motion for lung biopsy.

PubMed

Yang, Yunpeng; Jiang, Shan; Yang, Zhiyong; Yuan, Wei; Dou, Huaisu; Wang, Wei; Zhang, Daguang; Bian, Yuan

2017-04-01

Nowadays, biopsy is a decisive method of lung cancer diagnosis, whereas lung biopsy is time-consuming, complex and inaccurate. So a computed tomography-compatible robot for rapid and precise lung biopsy is developed in this article. According to the actual operation process, the robot is divided into two modules: 4-degree-of-freedom position module for location of puncture point is appropriate for patient's almost all positions and 3-degree-of-freedom tendon-based orientation module with remote center of motion is compact and computed tomography-compatible to orientate and insert needle automatically inside computed tomography bore. The workspace of the robot surrounds patient's thorax, and the needle tip forms a cone under patient's skin. A new error model of the robot based on screw theory is proposed in view of structure error and actuation error, which are regarded as screw motions. Simulation is carried out to verify the precision of the error model contrasted with compensation via inverse kinematics. The results of insertion experiment on specific phantom prove the feasibility of the robot with mean error of 1.373 mm in laboratory environment, which is accurate enough to replace manual operation.

Retraction of the Plunger on a Syringe of Hyaluronic Acid Before Injection: Are We Safe?

PubMed

Carey, Wayne; Weinkle, Susan

2015-12-01

Controversy exists concerning the need for aspiration before injection with hyaluronic acid (HA) fillers. The authors undertook a study of HA products to determine if blood could be aspirated back into a syringe of HA when the needle has been primed or filled with HA. Two studies were set up to determine if or when blood could be withdrawn from a heparinized fresh tube of blood into the HA syringe. Two different techniques were tested; one using a slow-pull retraction of the plunger and up to a 5-second waiting time before release versus a rapid pullback and quick release. Review of these data demonstrates that the usual clinical method, which involves quick withdrawal and instant release of the syringe plunger does not allow for sufficient removal of the filler found intraluminal in the needle and may give rise to false negative results in vitro and likely in vivo with the exception being the Galderma/Medicis products. In summary, withdrawal of the syringe plunger with no visible blood in the syringe does not eliminate the possibility of intravascular placement of the syringe needle.

Accuracy of frame-based stereotactic depth electrode implantation during craniotomy for subdural grid placement.

PubMed

Munyon, Charles N; Koubeissi, Mohamad Z; Syed, Tanvir U; Lüders, Hans O; Miller, Jonathan P

2013-01-01

Frame-based stereotaxy and open craniotomy may seem mutually exclusive, but invasive electrophysiological monitoring can require broad sampling of the cortex and precise targeting of deeper structures. The purpose of this study is to describe simultaneous frame-based insertion of depth electrodes and craniotomy for placement of subdural grids through a single surgical field and to determine the accuracy of depth electrodes placed using this technique. A total of 6 patients with intractable epilepsy underwent placement of a stereotactic frame with the center of the planned cranial flap equidistant from the fixation posts. After volumetric imaging, craniotomy for placement of subdural grids was performed. Depth electrodes were placed using frame-based stereotaxy. Postoperative CT determined the accuracy of electrode placement. A total of 31 depth electrodes were placed. Mean distance of distal electrode contact from the target was 1.0 ± 0.15 mm. Error was correlated to distance to target, with an additional 0.35 mm error for each centimeter (r = 0.635, p < 0.001); when corrected, there was no difference in accuracy based on target structure or method of placement (prior to craniotomy vs. through grid, p = 0.23). The described technique for craniotomy through a stereotactic frame allows placement of subdural grids and depth electrodes without sacrificing the accuracy of a frame or requiring staged procedures.

Ultrasound-guided Subclavian Vein Cannulation Using a Micro-Convex Ultrasound Probe

PubMed Central

Fair, James; Hirshberg, Eliotte L.; Grissom, Colin K.; Brown, Samuel M.

2014-01-01

Background: The subclavian vein is the preferred site for central venous catheter placement due to infection risk and patient comfort. Ultrasound guidance is useful in cannulation of other veins, but for the subclavian vein, current ultrasound-guided techniques using high-frequency linear array probes are generally limited to axillary vein cannulation. Methods: We report a series of patients who underwent clinically indicated subclavian venous catheter placement using a micro-convex pediatric probe for real-time guidance in the vein’s longitudinal axis. We identified rates of successful placement and complications by chart review. Results: Twenty-four catheters were placed using the micro-convex pediatric probe with confirmation of placement of the needle medial to the lateral border of the first rib. Sixteen of the catheters were placed by trainee physicians. In 23 patients, the catheter was placed without complication (hematoma, pneumothorax, infection). In one patient, the vein could not be safely cannulated without risk of arterial puncture, so an alternative site was selected. Conclusions: Infraclavicular subclavian vein cannulation using real-time ultrasound with a micro-convex pediatric probe appears to be a safe and effective method of placing subclavian vascular catheters. This technique merits further study to confirm safety and efficacy. PMID:24611628

Pinus Monophylla (Single Needled Pinyon Pine) show morphological changes in needle cell size and stomata over the past 100 years of rising CO2 in Western Arid Ecosystems.

NASA Astrophysics Data System (ADS)

Van De Water, P. K.

2016-12-01

The size, frequency, and morphology of leaf surface stomata is used to reconstruct past levels of atmospheric carbon dioxide over geologic time. This technique relies on measuring cell and cell-clusters to correlate with changes of known carbon dioxide levels in the atmosphere. Unfortunately, not all plants are suitable because the occurrence and placement of stomatal cell-complexes differ significantly between plant families. Monocot and dicot angiosperms exhibit different types of stomata and stomatal complexes that lack order and thus are unsuitable. But, in gymnosperms, the number and distribution of stomata and pavement cells is formalized and can be used to reconstruct past atmospheric carbon dioxide levels. However, characteristic of each plant species must still be considered. For example, conifers are useful but are divided into two-needle to five-needle pines, or have irregular surface morphology (Pseudotsuga sp. and Tsuga sp. needles). This study uses Pinus monophylla an undivided needle morphology, that being a cylinder has no interior surface cells. Pinus monophylla (single needle pinyon) needles were collected along Geiger Grade (Nevada State Highway 341, Reno) in 2005 and 2013 from 1500m to 2195m. Herbarium samples were also collected from 13 historic collections made between 1911 and 1994. The study determined changes with elevation and/or over time using in these populations. Using Pinus monophylla, insured needles represented a single surface with stomata, stomatal complex cells, and co-occurring pavement cell types. Results show decreased stomatal densities (stomata/area), stomatal index (stomata/stomata + epidermal cells) and stable stomata per row (stomata/row) . Epidermal cell density (Epidermal Cells /Area), and Pavement cell density (Pavement cell/area) track stomatal density similarly. Data comparison, using elevation in the 2005 and 2013 collections showed no-significant trends. Individual stomatal complexes show no differences in the size and shape over time or with elevation. Stomata morphology and the stomatal pores appear conservative. However some complex cells show a morphology suggesting they are not fully formed and functional. These characteristics appear often in the modern material suggesting some stomata never fully develop.

Vascular access cannulation in hemodialysis patients - a survey of current practice and its relation to dialysis dose.

PubMed

Gauly, Adelheid; Parisotto, Maria Teresa; Skinder, Aleksandra; Schoder, Volker; Furlan, Andreja; Schuh, Erika; Marcelli, Daniele

2011-01-01

The appropriate use of vascular access is of fundamental importance in the treatment of hemodialysis (HD) patients. This survey entailed collecting data on current practice of vascular access cannulation to assess its relation to dialysis dose. This international, multicenter, observational, cross-sectional survey was performed in 171 dialysis centers of the European dialysis network of Fresenius Medical Care in Europe and South Africa during April 2009. Practice patterns of vascular access cannulations were documented by means of a 24-item questionnaire. Dialysis dose from the documented hemodialysis treatments was derived from the clinical database EuCliD®. In total, 10,807 cannulations in hemodialysis patients with either arteriovenous fistula (91%) or arteriovenous graft (9%) were documented. For the puncture, the area technique was applied most frequently using 15G and 16G needles. Blood flow rates were mostly between 300 and 400 mL/min and adjusted to the needle size used. In two-thirds of cases the arterial needle was placed first, mostly in an antegrade direction, with an average distance to the venous needle of 7.0±3.7 cm. More than two-thirds of the cannulations were performed by nurses with more than 5 years of experience in dialysis. A logistic regression model revealed a significantly higher odds ratio to attain Kt/V = 1.2 for retrograde placement of the arterial needle, and for using needles with bigger diameter. This survey covered a broad number of countries and centers and provides information on current practice of vascular access cannulation, their effect on dialysis dose, and serves as feedback to the dialysis centers for their quality management process.

Gadolinium Use in Spine Pain Management Procedures for Patients with Contrast Allergies: Results in 527 Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safriel, Yair; Ang, Roberto; Ali, Muhammed

2008-03-15

Introduction. To review the safety and efficacy of gadolinium in spine pain management procedures in patients at high risk for a contrast reaction and who are not suitable candidates for the use of standard non-ionic contrast. Methods. We reviewed records over a 61-month period of all image-guided spinal pain management procedures where patients had allergies making them unsuitable candidates for standard non-ionic contrast and where gadolinium was used to confirm needle tip placement prior to injection of medication. Results. Three hundred and four outpatients underwent 527 procedures. A spinal needle was used in all but 41 procedures. Gadolinium was visualizedmore » using portable C-arm fluoroscopy in vivo allowing for confirmation of needle tip location. The gadolinium dose ranged from 0.2 to 10 ml per level. The highest dose received by one patient was 15.83 ml intradiscally during a three-level discogram. Three hundred and one patients were discharged without complication or known delayed complications. One patient had documented intrathecal injection but without sequelae and 2 patients who underwent cervical procedures experienced seizures requiring admission to the intensive care unit. Both the latter patients were discharged without any further complications. Conclusion. Based on our experience we recommend using gadolinium judiciously for needle tip confirmation. We feel more confident using gadolinium in the lumbar spine and in cervical nerve blocks. Gadolinium should probably not be used as an injectate volume expander. The indications for gadolinium use in cervical needle-guided spine procedures are less clear and use of a blunt-tipped needle should be considered.« less

Needle-tissue interactive mechanism and steering control in image-guided robot-assisted minimally invasive surgery: a review.

PubMed

Li, Pan; Yang, Zhiyong; Jiang, Shan

2018-06-01

Image-guided robot-assisted minimally invasive surgery is an important medicine procedure used for biopsy or local target therapy. In order to reach the target region not accessible using traditional techniques, long and thin flexible needles are inserted into the soft tissue which has large deformation and nonlinear characteristics. However, the detection results and therapeutic effect are directly influenced by the targeting accuracy of needle steering. For this reason, the needle-tissue interactive mechanism, path planning, and steering control are investigated in this review by searching literatures in the last 10 years, which results in a comprehensive overview of the existing techniques with the main accomplishments, limitations, and recommendations. Through comprehensive analyses, surgical simulation for insertion into multi-layer inhomogeneous tissue is verified as a primary and propositional aspect to be explored, which accurately predicts the nonlinear needle deflection and tissue deformation. Investigation of the path planning of flexible needles is recommended to an anatomical or a deformable environment which has characteristics of the tissue deformation. Nonholonomic modeling combined with duty-cycled spinning for needle steering, which tracks the tip position in real time and compensates for the deviation error, is recommended as a future research focus in the steering control in anatomical and deformable environments. Graphical abstract a Insertion force when the needle is inserted into soft tissue. b Needle deflection model when the needle is inserted into soft tissue [68]. c Path planning in anatomical environments [92]. d Duty-cycled spinning incorporated in nonholonomic needle steering [64].

Optimal accelerometer placement on a robot arm for pose estimation

NASA Astrophysics Data System (ADS)

Wijayasinghe, Indika B.; Sanford, Joseph D.; Abubakar, Shamsudeen; Saadatzi, Mohammad Nasser; Das, Sumit K.; Popa, Dan O.

2017-05-01

The performance of robots to carry out tasks depends in part on the sensor information they can utilize. Usually, robots are fitted with angle joint encoders that are used to estimate the position and orientation (or the pose) of its end-effector. However, there are numerous situations, such as in legged locomotion, mobile manipulation, or prosthetics, where such joint sensors may not be present at every, or any joint. In this paper we study the use of inertial sensors, in particular accelerometers, placed on the robot that can be used to estimate the robot pose. Studying accelerometer placement on a robot involves many parameters that affect the performance of the intended positioning task. Parameters such as the number of accelerometers, their size, geometric placement and Signal-to-Noise Ratio (SNR) are included in our study of their effects for robot pose estimation. Due to the ubiquitous availability of inexpensive accelerometers, we investigated pose estimation gains resulting from using increasingly large numbers of sensors. Monte-Carlo simulations are performed with a two-link robot arm to obtain the expected value of an estimation error metric for different accelerometer configurations, which are then compared for optimization. Results show that, with a fixed SNR model, the pose estimation error decreases with increasing number of accelerometers, whereas for a SNR model that scales inversely to the accelerometer footprint, the pose estimation error increases with the number of accelerometers. It is also shown that the optimal placement of the accelerometers depends on the method used for pose estimation. The findings suggest that an integration-based method favors placement of accelerometers at the extremities of the robot links, whereas a kinematic-constraints-based method favors a more uniformly distributed placement along the robot links.

Improvement of the Mair scoring system using structural equations modeling for classifying the diagnostic adequacy of cytology material from thyroid lesions.

PubMed

Kulkarni, H R; Kamal, M M; Arjune, D G

1999-12-01

The scoring system developed by Mair et al. (Acta Cytol 1989;33:809-813) is frequently used to grade the quality of cytology smears. Using a one-factor analytic structural equations model, we demonstrate that the errors in measurement of the parameters used in the Mair scoring system are highly and significantly correlated. We recommend the use of either a multiplicative scoring system, using linear scores, or an additive scoring system, using exponential scores, to correct for the correlated errors. We suggest that the 0, 1, and 2 points used in the Mair scoring system be replaced by 1, 2, and 4, respectively. Using data on fine-needle biopsies of 200 thyroid lesions by both fine-needle aspiration (FNA) and fine-needle capillary sampling (FNC), we demonstrate that our modification of the Mair scoring system is more sensitive and more consistent with the structural equations model. Therefore, we recommend that the modified Mair scoring system be used for classifying the diagnostic adequacy of cytology smears. Diagn. Cytopathol. 1999;21:387-393. Copyright 1999 Wiley-Liss, Inc.

Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: part II--Optimization of structural sensor placement.

PubMed

Halim, Dunant; Cheng, Li; Su, Zhongqing

2011-04-01

The work proposed an optimization approach for structural sensor placement to improve the performance of vibro-acoustic virtual sensor for active noise control applications. The vibro-acoustic virtual sensor was designed to estimate the interior sound pressure of an acoustic-structural coupled enclosure using structural sensors. A spectral-spatial performance metric was proposed, which was used to quantify the averaged structural sensor output energy of a vibro-acoustic system excited by a spatially varying point source. It was shown that (i) the overall virtual sensing error energy was contributed additively by the modal virtual sensing error and the measurement noise energy; (ii) each of the modal virtual sensing error system was contributed by both the modal observability levels for the structural sensing and the target acoustic virtual sensing; and further (iii) the strength of each modal observability level was influenced by the modal coupling and resonance frequencies of the associated uncoupled structural/cavity modes. An optimal design of structural sensor placement was proposed to achieve sufficiently high modal observability levels for certain important panel- and cavity-controlled modes. Numerical analysis on a panel-cavity system demonstrated the importance of structural sensor placement on virtual sensing and active noise control performance, particularly for cavity-controlled modes.

A pilot study of the utility of a laboratory-based spinal fixation training program for neurosurgical residents.

PubMed

Sundar, Swetha J; Healy, Andrew T; Kshettry, Varun R; Mroz, Thomas E; Schlenk, Richard; Benzel, Edward C

2016-05-01

OBJECTIVE Pedicle and lateral mass screw placement is technically demanding due to complex 3D spinal anatomy that is not easily visualized. Neurosurgical and orthopedic surgery residents must be properly trained in such procedures, which can be associated with significant complications and associated morbidity. Current training in pedicle and lateral mass screw placement involves didactic teaching and supervised placement in the operating room. The objective of this study was to assess whether teaching residents to place pedicle and lateral mass screws using navigation software, combined with practice using cadaveric specimens and Sawbones models, would improve screw placement accuracy. METHODS This was a single-blinded, prospective, randomized pilot study with 8 junior neurosurgical residents and 2 senior medical students with prior neurosurgery exposure. Both the study group and the level of training-matched control group (each group with 4 level of training-matched residents and 1 senior medical student) were exposed to a standardized didactic education regarding spinal anatomy and screw placement techniques. The study group was exposed to an additional pilot program that included a training session using navigation software combined with cadaveric specimens and accessibility to Sawbones models. RESULTS A statistically significant reduction in overall surgical error was observed in the study group compared with the control group (p = 0.04). Analysis by spinal region demonstrated a significant reduction in surgical error in the thoracic and lumbar regions in the study group compared with controls (p = 0.02 and p = 0.04, respectively). The study group also was observed to place screws more optimally in the cervical, thoracic, and lumbar regions (p = 0.02, p = 0.04, and p = 0.04, respectively). CONCLUSIONS Surgical resident education in pedicle and lateral mass screw placement is a priority for training programs. This study demonstrated that compared with a didactic-only training model, using navigation simulation with cadavers and Sawbones models significantly reduced the number of screw placement errors in a laboratory setting.

Synthesis of Arbitrary Quantum Circuits to Topological Assembly: Systematic, Online and Compact.

PubMed

Paler, Alexandru; Fowler, Austin G; Wille, Robert

2017-09-05

It is challenging to transform an arbitrary quantum circuit into a form protected by surface code quantum error correcting codes (a variant of topological quantum error correction), especially if the goal is to minimise overhead. One of the issues is the efficient placement of magic state distillation sub circuits, so-called distillation boxes, in the space-time volume that abstracts the computation's required resources. This work presents a general, systematic, online method for the synthesis of such circuits. Distillation box placement is controlled by so-called schedulers. The work introduces a greedy scheduler generating compact box placements. The implemented software, whose source code is available at www.github.com/alexandrupaler/tqec, is used to illustrate and discuss synthesis examples. Synthesis and optimisation improvements are proposed.

Differential-Drive Mobile Robot Control Design based-on Linear Feedback Control Law

NASA Astrophysics Data System (ADS)

Nurmaini, Siti; Dewi, Kemala; Tutuko, Bambang

2017-04-01

This paper deals with the problem of how to control differential driven mobile robot with simple control law. When mobile robot moves from one position to another to achieve a position destination, it always produce some errors. Therefore, a mobile robot requires a certain control law to drive the robot’s movement to the position destination with a smallest possible error. In this paper, in order to reduce position error, a linear feedback control is proposed with pole placement approach to regulate the polynoms desired. The presented work leads to an improved understanding of differential-drive mobile robot (DDMR)-based kinematics equation, which will assist to design of suitable controllers for DDMR movement. The result show by using the linier feedback control method with pole placement approach the position error is reduced and fast convergence is achieved.

Use of modeling to identify vulnerabilities to human error in laparoscopy.

PubMed

Funk, Kenneth H; Bauer, James D; Doolen, Toni L; Telasha, David; Nicolalde, R Javier; Reeber, Miriam; Yodpijit, Nantakrit; Long, Myra

2010-01-01

This article describes an exercise to investigate the utility of modeling and human factors analysis in understanding surgical processes and their vulnerabilities to medical error. A formal method to identify error vulnerabilities was developed and applied to a test case of Veress needle insertion during closed laparoscopy. A team of 2 surgeons, a medical assistant, and 3 engineers used hierarchical task analysis and Integrated DEFinition language 0 (IDEF0) modeling to create rich models of the processes used in initial port creation. Using terminology from a standardized human performance database, detailed task descriptions were written for 4 tasks executed in the process of inserting the Veress needle. Key terms from the descriptions were used to extract from the database generic errors that could occur. Task descriptions with potential errors were translated back into surgical terminology. Referring to the process models and task descriptions, the team used a modified failure modes and effects analysis (FMEA) to consider each potential error for its probability of occurrence, its consequences if it should occur and be undetected, and its probability of detection. The resulting likely and consequential errors were prioritized for intervention. A literature-based validation study confirmed the significance of the top error vulnerabilities identified using the method. Ongoing work includes design and evaluation of procedures to correct the identified vulnerabilities and improvements to the modeling and vulnerability identification methods. Copyright 2010 AAGL. Published by Elsevier Inc. All rights reserved.

Initiation of labor analgesia with injection of local anesthetic through the epidural needle compared to the catheter.

PubMed

Ristev, Goran; Sipes, Angela C; Mahoney, Bryan; Lipps, Jonathan; Chan, Gary; Coffman, John C

2017-01-01

The rationale for injection of epidural medications through the needle is to promote sooner onset of pain relief relative to dosing through the epidural catheter given that needle injection can be performed immediately after successful location of the epidural space. Some evidence indicates that dosing medications through the epidural needle results in faster onset and improved quality of epidural anesthesia compared to dosing through the catheter, though these dosing techniques have not been compared in laboring women. This investigation was performed to determine whether dosing medication through the epidural needle improves the quality of analgesia, level of sensory blockade, or onset of pain relief measured from the time of epidural medication injection. In this double-blinded prospective investigation, healthy term laboring women (n=60) received labor epidural placement upon request. Epidural analgesia was initiated according to the assigned randomization group: 10 mL loading dose (0.125% bupivacaine with fentanyl 2 µg/mL) through either the epidural needle or the catheter, given in 5 mL increments spaced 2 minutes apart. Verbal rating scale (VRS) pain scores (0-10) and pinprick sensory levels were documented to determine the rates of analgesic and sensory blockade onset. No significant differences were observed in onset of analgesia or sensory blockade from the time of injection between study groups. The estimated difference in the rate of pain relief (VRS/minute) was 0.04 (95% CI: -0.01 to 0.11; p =0.109), and the estimated difference in onset of sensory blockade (sensory level/minute) was 0.63 (95% CI: -0.02 to 0.15; p =0.166). The time to VRS ≤3 and level of sensory block 20 minutes after dosing were also similar between groups. No differences in patient satisfaction, or maternal or fetal complications were observed. This investigation observed that epidural needle and catheter injection of medications result in similar onset of analgesia and sensory blockade, quality of labor analgesia, patient satisfaction, and complication rates.

SU-F-BRA-04: Prostate HDR Brachytherapy with Multichannel Robotic System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph, F Maria; Podder, T; Yu, Y

Purpose: High-dose-rate (HDR) brachytherapy is gradually becoming popular in treating patients with prostate cancers. However, placement of the HDR needles at desired locations into the patient is challenging. Application of robotic system may improve the accuracy of the clinical procedure. This experimental study is to evaluate the feasibility of using a multichannel robotic system for prostate HDR brachytherapy. Methods: In this experimental study, the robotic system employed was a 6-DOF Multichannel Image-guided Robotic Assistant for Brachytherapy (MIRAB), which was designed and fabricated for prostate seed implantation. The MIRAB has the provision of rotating 16 needles while inserting them. Ten prostatemore » HDR brachytherapy needles were simultaneously inserted using MIRAB into a commercially available prostate phantom. After inserting the needles into the prostate phantom at desired locations, 2mm thick CT slices were obtained for dosimetric planning. HDR plan was generated using Oncetra planning system with a total prescription dose of 34Gy in 4 fractions. Plan quality was evaluated considering dose coverage to prostate and planning target volume (PTV), with 3mm margin around prostate, as well as the dose limit to the organs at risk (OARs) following the American Brachytherapy Society (ABS) guidelines. Results: From the CT scan, it is observed that the needles were inserted straight into the desired locations and they were adequately spaced and distributed for a clinically acceptable HDR plan. Coverage to PTV and prostate were about 91% (V100= 91%) and 96% (V100=96%), respectively. Dose to 1cc of urethra, rectum, and bladder were within the ABS specified limits. Conclusion: The MIRAB was able to insert multiple needles simultaneously into the prostate precisely. By controlling the MIRAB to insert all the ten utilized needles into the prostate phantom, we could achieve the robotic HDR brachytherapy successfully. Further study for assessing the system’s performance and reliability is in progress.« less

Three-Dimensional Ultrasound-Guided Real-Time Midline Epidural Needle Placement with Epiguide: A Prospective Feasibility Study.

PubMed

Beigi, Parmida; Malenfant, Paul; Rasoulian, Abtin; Rohling, Robert; Dube, Alison; Gunka, Vit

2017-01-01

Current 2-D ultrasound technology is unable to perform a midline neuraxial needle insertion under real-time ultrasound guidance using a standard needle and without an assistant. The aim of the work described here was to determine the feasibility of a new technology providing such capability, starting with a study evaluating the selected puncture site. A novel 3-D ultrasound imaging technique was designed using thick-slice rendering in conjunction with a custom needle guide (3DUS + Epiguide). A clinical feasibility study evaluated the ability of 3DUS + Epiguide to identify the epidural needle puncture site for a midline insertion in the lumbar spine. We hypothesized that (i) the puncture site identified by 3DUS + Epiguide was within a 5-mm radius from the site chosen by standard palpation, and (ii) the difference between the two puncture sites was not correlated to the patient characteristics age, weight, height, body mass index and gestational age. The mean (±standard deviation) distances between puncture sites determined by 3DUS + Epiguide and palpation were 3.1 (±1.7) mm and 2.8 (±1.3) mm, for the L2-3 and L3-4 interspaces of 20 patients, respectively. Distances were comparable to intra-observer variability, indicating the potential for a thick-slice rendering of 3-D ultrasound along the Epiguide trajectory to select the puncture site of a midline neuraxial needle insertion. The long-term potential benefits of this system include increased efficiency and use of anesthesia, and a reduction in the frequency and severity of the complications from incorrect needle insertions. Epidural success in the most difficult cases (e.g., the obese) will be the focus of future work. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Teleoperation of steerable flexible needles by combining kinesthetic and vibratory feedback.

PubMed

Pacchierotti, Claudio; Abayazid, Momen; Misra, Sarthak; Prattichizzo, Domenico

2014-01-01

Needle insertion in soft-tissue is a minimally invasive surgical procedure that demands high accuracy. In this respect, robotic systems with autonomous control algorithms have been exploited as the main tool to achieve high accuracy and reliability. However, for reasons of safety and responsibility, autonomous robotic control is often not desirable. Therefore, it is necessary to focus also on techniques enabling clinicians to directly control the motion of the surgical tools. In this work, we address that challenge and present a novel teleoperated robotic system able to steer flexible needles. The proposed system tracks the position of the needle using an ultrasound imaging system and computes needle's ideal position and orientation to reach a given target. The master haptic interface then provides the clinician with mixed kinesthetic-vibratory navigation cues to guide the needle toward the computed ideal position and orientation. Twenty participants carried out an experiment of teleoperated needle insertion into a soft-tissue phantom, considering four different experimental conditions. Participants were provided with either mixed kinesthetic-vibratory feedback or mixed kinesthetic-visual feedback. Moreover, we considered two different ways of computing ideal position and orientation of the needle: with or without set-points. Vibratory feedback was found more effective than visual feedback in conveying navigation cues, with a mean targeting error of 0.72 mm when using set-points, and of 1.10 mm without set-points.

The first clinical application of planning software for laparoscopic microwave thermosphere ablation of malignant liver tumours.

PubMed

Berber, Eren

2015-07-01

Liver tumour ablation is an operator-dependent procedure. The determination of the optimum needle trajectory and correct ablation parameters could be challenging. The aim of this study was to report the utility of a new, procedure planning software for microwave ablation (MWA) of liver tumours. This was a feasibility study in a pilot group of five patients with nine metastatic liver tumours who underwent laparoscopic MWA. Pre-operatively, parameters predicting the desired ablation zones were calculated for each tumour. Intra-operatively, this planning strategy was followed for both antenna placement and energy application. Post-operative 2-week computed tomography (CT) scans were performed to evaluate complete tumour destruction. The patients had an average of two tumours (range 1-4), measuring 1.9 ± 0.4 cm (range 0.9-4.4 cm). The ablation time was 7.1 ± 1.3 min (range 2.5-10 min) at 100W. There were no complications or mortality. The patients were discharged home on post-operative day (POD) 1. At 2-week CT scans, there were no residual tumours, with a complete ablation demonstrated in all lesions. This study describes and validates pre-treatment planning software for MWA of liver tumours. This software was found useful to determine precisely the ablation parameters and needle placement to create a predicted zone of ablation. © 2015 International Hepato-Pancreato-Biliary Association.

Epidural Catheter Placement in Morbidly Obese Parturients with the Use of an Epidural Depth Equation prior to Ultrasound Visualization

PubMed Central

Singh, Sukhdip; Wirth, Keith M.; Phelps, Amy L.; Badve, Manasi H.; Shah, Tanmay H.; Vallejo, Manuel C.

2013-01-01

Background. Previously, Balki determined the Pearson correlation coefficient with the use of ultrasound (US) was 0.85 in morbidly obese parturients. We aimed to determine if the use of the epidural depth equation (EDE) in conjunction with US can provide better clinical correlation in estimating the distance from the skin to the epidural space in morbidly obese parturients. Methods. One hundred sixty morbidly obese (≥40 kg/m2) parturients requesting labor epidural analgesia were enrolled. Before epidural catheter placement, EDE was used to estimate depth to the epidural space. This estimation was used to help visualize the epidural space with the transverse and midline longitudinal US views and to measure depth to epidural space. The measured epidural depth was made available to the resident trainee before needle insertion. Actual needle depth (ND) to the epidural space was recorded. Results. Pearson's correlation coefficients comparing actual (ND) versus US estimated depth to the epidural space in the longitudinal median and transverse planes were 0.905 (95% CI: 0.873 to 0.929) and 0.899 (95% CI: 0.865 to 0.925), respectively. Conclusion. Use of the epidural depth equation (EDE) in conjunction with the longitudinal and transverse US views results in better clinical correlation than with the use of US alone. PMID:23983645

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maynar, Manuel; Llorens, Rafael; Lopez-Sanchez, Carmen

Purpose. A method to create an extraluminal femoropopliteal bypass graft using endovascular techniques was evaluated in situ on cadaver extremities in an attempt to develop a minimally invasive alternative technique for the management of infrainguinal occlusive arterial disease. Methods. The endovascular placement of an extraluminal femoropopliteal bypass graft was undertaken in 5 cadaver legs. Following percutaneous access to the popliteal artery (PA) or common femoral artery (CFA), a Rosch-Uchida needle was used to perforate the vascular wall, followed by the creation of an extraluminal tract using a looped wire and catheter. Once the desired level was reached the needle wasmore » again used to perforate the vascular wall of the proximal superficial femoral artery (SFA) or PA depending on the access used. Self-expanding expanded polytetrafluoroethylene (ePTFE) stent-grafts were then deployed to establish the extraluminal femoropopliteal bypass connecting the two arterial puncture sites. Following dilatation of the stent-graft, angiography was performed to assess the endoprostheses and to look for contrast leaks. Results. Technical success was achieved in all 5 legs. Procedure time varied from 15 to 30 min. The angiographic studies performed immediately after completion of the bypass procedure showed patency of the grafts with no evidence of kinking or leakage in any of the cases. Conclusion. This study has proved that the endovascular placement of an extraluminal femoropopliteal bypass graft in human cadaver legs using endovascular techniques under fluoroscopic control is technically feasible.« less

Percutaneous radiofrequency ablation of lung metastases from colorectal carcinoma under C-arm cone beam CT guidance.

PubMed

Amouyal, G; Pernot, S; Déan, C; Cholley, B; Scotté, F; Sapoval, M; Pellerin, O

2017-11-01

The aim of this study was to assess the feasibility, safety and efficacy of percutaneous radiofrequency ablation of lung metastases from colorectal carcinoma using C-arm cone beam computed tomography (CBCT) guidance. This single-center prospective observational study was performed from August 2013 to August 2016, and included consecutive patients referred for radiofrequency ablation of lung metastases from colorectal cancer. Radiofrequency ablation procedures were performed under C-arm CBCT guidance. Feasibility was assessed by probe accuracy placement, time to accurate placement and number of C-arm CBCT acquisitions to reach the target lesion. Safety was assessed by the report of adverse event graded using the common terminology criteria for adverse events (CTCAE-V4.0). Efficacy was assessed by metastases response rate using RECIST 1.1 and 18 FDG-PET-CT tumor uptake at 6months. Fifty-four consecutive patients (32 men, 22 women) with a mean age of 63±8 (SD) years (range: 51-81years) with a total of 56 lung metastasis from colorectal metastases were treated in a single session. The mean tumor diameter was 25.6±4.5 (SD)mm (range: 17-31mm). Median time to insert the needle into the target lesion was 10min (range: 5-25min). Median number of needles repositioning and C-arm CBCT acquisition per patient was 1 (range: 0-3) and 4 (range: 3-6) respectively. The accuracy for radiofrequency ablation probe placement was 2±0.2 (SD)mm (range: 0-9mm). Pneumothorax requiring chest tube placement occurred in one patient (CTCAE-V4.0 grade 3). At 6months, all patients were alive with tumor response rate of -27% and had no significant activity on the 18 FDG-PET CT follow-up. Percutaneous radiofrequency ablation of lung metastases from colorectal cancer under C-arm CBCT guidance is feasible and safe, with immediate and short-term results similar to those obtained using conventional CT guidance. Copyright © 2017 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Real-time tracking of liver motion and deformation using a flexible needle

PubMed Central

Lei, Peng; Moeslein, Fred; Wood, Bradford J.

2012-01-01

Purpose A real-time 3D image guidance system is needed to facilitate treatment of liver masses using radiofrequency ablation, for example. This study investigates the feasibility and accuracy of using an electromagnetically tracked flexible needle inserted into the liver to track liver motion and deformation. Methods This proof-of-principle study was conducted both ex vivo and in vivo with a CT scanner taking the place of an electromagnetic tracking system as the spatial tracker. Deformations of excised livers were artificially created by altering the shape of the stage on which the excised livers rested. Free breathing or controlled ventilation created deformations of live swine livers. The positions of the needle and test targets were determined through CT scans. The shape of the needle was reconstructed using data simulating multiple embedded electromagnetic sensors. Displacement of liver tissues in the vicinity of the needle was derived from the change in the reconstructed shape of the needle. Results The needle shape was successfully reconstructed with tracking information of two on-needle points. Within 30 mm of the needle, the registration error of implanted test targets was 2.4 ± 1.0 mm ex vivo and 2.8 ± 1.5 mm in vivo. Conclusion A practical approach was developed to measure the motion and deformation of the liver in real time within a region of interest. The approach relies on redesigning the often-used seeker needle to include embedded electromagnetic tracking sensors. With the nonrigid motion and deformation information of the tracked needle, a single- or multimodality 3D image of the intraprocedural liver, now clinically obtained with some delay, can be updated continuously to monitor intraprocedural changes in hepatic anatomy. This capability may be useful in radiofrequency ablation and other percutaneous ablative procedures. PMID:20700662

A comparison of needle tip localization accuracy using 2D and 3D trans-rectal ultrasound for high-dose-rate prostate cancer brachytherapy treatment planning

NASA Astrophysics Data System (ADS)

Hrinivich, W. Thomas; Hoover, Douglas A.; Surry, Kathleen; Edirisinghe, Chandima; Montreuil, Jacques; D'Souza, David; Fenster, Aaron; Wong, Eugene

2016-03-01

Background: High-dose-rate brachytherapy (HDR-BT) is a prostate cancer treatment option involving the insertion of hollow needles into the gland through the perineum to deliver a radioactive source. Conventional needle imaging involves indexing a trans-rectal ultrasound (TRUS) probe in the superior/inferior (S/I) direction, using the axial transducer to produce an image set for organ segmentation. These images have limited resolution in the needle insertion direction (S/I), so the sagittal transducer is used to identify needle tips, requiring a manual registration with the axial view. This registration introduces a source of uncertainty in the final segmentations and subsequent treatment plan. Our lab has developed a device enabling 3D-TRUS guided insertions with high S/I spatial resolution, eliminating the need to align axial and sagittal views. Purpose: To compare HDR-BT needle tip localization accuracy between 2D and 3D-TRUS. Methods: 5 prostate cancer patients underwent conventional 2D TRUS guided HDR-BT, during which 3D images were also acquired for post-operative registration and segmentation. Needle end-length measurements were taken, providing a gold standard for insertion depths. Results: 73 needles were analyzed from all 5 patients. Needle tip position differences between imaging techniques was found to be largest in the S/I direction with mean+/-SD of -2.5+/-4.0 mm. End-length measurements indicated that 3D TRUS provided statistically significantly lower mean+/-SD insertion depth error of -0.2+/-3.4 mm versus 2.3+/-3.7 mm with 2D guidance (p < .001). Conclusions: 3D TRUS may provide more accurate HDR-BT needle localization than conventional 2D TRUS guidance for the majority of HDR-BT needles.

Comparison of concentric needle versus hooked-wire electrodes in the canine larynx.

PubMed

Jaffe, D M; Solomon, N P; Robinson, R A; Hoffman, H T; Luschei, E S

1998-05-01

The use of a specific electrode type in laryngeal electromyography has not been standardized. Laryngeal electromyography is usually performed with hooked-wire electrodes or concentric needle electrodes. Hooked-wire electrodes have the advantage of allowing laryngeal movement with ease and comfort, whereas the concentric needle electrodes have benefits from a technical aspect and may be advanced, withdrawn, or redirected during attempts to appropriately place the electrode. This study examines whether hooked-wire electrodes permit more stable recordings than standard concentric needle electrodes at rest and after large-scale movements of the larynx and surrounding structures. A histologic comparison of tissue injury resulting from placement and removal of the two electrode types is also made by evaluation of the vocal folds. Electrodes were percutaneously placed into the thyroarytenoid muscles of 10 adult canines. Amplitude of electromyographic activity was measured and compared during vagal stimulation before and after large-scale laryngeal movements. Signal consistency over time was examined. Animals were killed and vocal fold injury was graded and compared histologically. Waveform morphology did not consistently differ between electrode types. The variability of electromyographic amplitude was greater for the hooked-wire electrode (p < 0.05), whereas the mean amplitude measures before and after large-scale laryngeal movements did not differ (p > 0.05). Inflammatory responses and hematoma formation were also similar. Waveform morphology of electromyographic signals registered from both electrode types show similar complex action potentials. There is no difference between the hooked-wire electrode and the concentric needle electrode in terms of electrode stability or vocal fold injury in the thyroarytenoid muscle after large-scale laryngeal movements.

Feasibility of ultrasound-guided sacroiliac joint injection considering sonoanatomic landmarks at two different levels in cadavers and patients.

PubMed

Klauser, Andrea; De Zordo, Tobias; Feuchtner, Gudrun; Sögner, Peter; Schirmer, Michael; Gruber, Johann; Sepp, Norbert; Moriggl, Bernhard

2008-11-15

Sacroiliitis is often caused by rheumatic diseases, and besides other therapeutic options, treatment consists of intraarticular injection of corticosteroids. The purpose of this study was to assess the feasibility of ultrasound (US)-guided sacroiliac joint (SI joint) injection at 2 different puncture levels in cadavers and patients when defined sonoanatomic landmarks were considered. After defining sonoanatomic landmarks, US-guided needle insertion was performed in 10 human cadavers (20 SI joints) at 2 different puncture sites. Upper level was defined at the level of the posterior sacral foramen 1 and lower level at the level of the posterior sacral foramen 2. In 10 patients with unilateral sacroiliitis, injection at the most feasible level was attempted. Computed tomography confirmed correct intraarticular needle placement in cadavers by showing the tip of the needle in the joint and intraarticular diffusion of contrast media in 16 (80%) of 20 SI joints (upper level 7 [70%] of 10; lower level 9 [90%] of 10). In all 4 cases in which needle insertion failed, intraarticular SI joint injection at the other level was successful. In patients, 100% of US-guided injections were successful (8 lower level, 2 upper level), with a mean pain relief of 8.6 after 3 months. US guidance of needle insertion into SI joints was feasible at both levels when defined sonoanatomic landmarks were used. If SI joint alterations do not allow for direct visualization of the dorsal joint space of the lower level, which is easier to access, the upper level might offer an appropriate alternative.

Noxious electrical stimulation of the pelvic floor and vagina induces transient voiding dysfunction in a rabbit survival model of pelvic floor dystonia.

PubMed

Dobberfuhl, Amy D; Spettel, Sara; Schuler, Catherine; Levin, Robert M; Dubin, Andrew H; De, Elise J B

2015-12-01

Existing data supports a relationship between pelvic floor dysfunction and lower urinary tract symptoms. We developed a survival model of pelvic floor dysfunction in the rabbit and evaluated cystometric (CMG), electromyographic (EMG) and ambulatory voiding behavior. Twelve female adult virgin rabbits were housed in metabolic cages to record voiding and defecation. Anesthetized CMG/EMG was performed before and after treatment animals (n=9) received bilateral tetanizing needle stimulation to the pubococcygeous (PC) muscle and controls (n=3) sham needle placement. After 7 days all animals were subjected to tetanizing transvaginal stimulation and CMG/EMG. After 5 days a final CMG/EMG was performed. Of rabbits that underwent needle stimulation 7 of 9 (78%) demonstrated dysfunctional CMG micturition contractions versus 6 of 12 (50%) after transvaginal stimulation. Needle stimulation of the PC musculature resulted in significant changes in: basal CMG pressure, precontraction pressure change, contraction pressure, interval between contractions and postvoid residual; with time to 3rd contraction increased from 38 to 53 minutes (p=0.008 vs. prestimulation). Vaginal noxious stimulation resulted in significant changes in: basal CMG pressure and interval between contractions; with time to 3rd contraction increased from 37 to 46 minutes (p=0.008 vs. prestimulation). Changes in cage parameters were primarily seen after direct needle stimulation. In a majority of animals, tetanizing electrical stimulation of the rabbit pelvic floor resulted in voiding changes suggestive of pelvic floor dysfunction as characterized by a larger bladder capacity, longer interval between contractions and prolonged contraction duration.

Can a virtual reality assessment of fine motor skill predict successful central line insertion?

PubMed

Mohamadipanah, Hossein; Parthiban, Chembian; Nathwani, Jay; Rutherford, Drew; DiMarco, Shannon; Pugh, Carla

2016-10-01

Due to the increased use of peripherally inserted central catheter lines, central lines are not performed as frequently. The aim of this study is to evaluate whether a virtual reality (VR)-based assessment of fine motor skills can be used as a valid and objective assessment of central line skills. Surgical residents (N = 43) from 7 general surgery programs performed a subclavian central line in a simulated setting. Then, they participated in a force discrimination task in a VR environment. Hand movements from the subclavian central line simulation were tracked by electromagnetic sensors. Gross movements as monitored by the electromagnetic sensors were compared with the fine motor metrics calculated from the force discrimination tasks in the VR environment. Long periods of inactivity (idle time) during needle insertion and lack of smooth movements, as detected by the electromagnetic sensors, showed a significant correlation with poor force discrimination in the VR environment. Also, long periods of needle insertion time correlated to the poor performance in force discrimination in the VR environment. This study shows that force discrimination in a defined VR environment correlates to needle insertion time, idle time, and hand smoothness when performing subclavian central line placement. Fine motor force discrimination may serve as a valid and objective assessment of the skills required for successful needle insertion when placing central lines. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic analysis of a needle insertion for soft materials: Arbitrary Lagrangian-Eulerian-based three-dimensional finite element analysis.

PubMed

Yamaguchi, Satoshi; Tsutsui, Kihei; Satake, Koji; Morikawa, Shigehiro; Shirai, Yoshiaki; Tanaka, Hiromi T

2014-10-01

Our goal was to develop a three-dimensional finite element model that enables dynamic analysis of needle insertion for soft materials. To demonstrate large deformation and fracture, we used the arbitrary Lagrangian-Eulerian (ALE) method for fluid analysis. We performed ALE-based finite element analysis for 3% agar gel and three types of copper needle with bevel tips. To evaluate simulation results, we compared the needle deflection and insertion force with corresponding experimental results acquired with a uniaxial manipulator. We studied the shear stress distribution of agar gel on various time scales. For 30°, 45°, and 60°, differences in deflections of each needle between both sets of results were 2.424, 2.981, and 3.737mm, respectively. For the insertion force, there was no significant difference for mismatching area error (p<0.05) between simulation and experimental results. Our results have the potential to be a stepping stone to develop pre-operative surgical planning to estimate an optimal needle insertion path for MR image-guided microwave coagulation therapy and for analyzing large deformation and fracture in biological tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

POD-based constrained sensor placement and field reconstruction from noisy wind measurements: A perturbation study

DOE PAGES

Zhang, Zhongqiang; Yang, Xiu; Lin, Guang

2016-04-14

Sensor placement at the extrema of Proper Orthogonal Decomposition (POD) is efficient and leads to accurate reconstruction of the wind field from a limited number of measure- ments. In this paper we extend this approach of sensor placement and take into account measurement errors and detect possible malfunctioning sensors. We use the 48 hourly spa- tial wind field simulation data sets simulated using the Weather Research an Forecasting (WRF) model applied to the Maine Bay to evaluate the performances of our methods. Specifically, we use an exclusion disk strategy to distribute sensors when the extrema of POD modes are close.more » It turns out that this strategy can also reduce the error of recon- struction from noise measurements. Also, by a cross-validation technique, we successfully locate the malfunctioning sensors.« less

Influence of model errors in optimal sensor placement

NASA Astrophysics Data System (ADS)

Vincenzi, Loris; Simonini, Laura

2017-02-01

The paper investigates the role of model errors and parametric uncertainties in optimal or near optimal sensor placements for structural health monitoring (SHM) and modal testing. The near optimal set of measurement locations is obtained by the Information Entropy theory; the results of placement process considerably depend on the so-called covariance matrix of prediction error as well as on the definition of the correlation function. A constant and an exponential correlation function depending on the distance between sensors are firstly assumed; then a proposal depending on both distance and modal vectors is presented. With reference to a simple case-study, the effect of model uncertainties on results is described and the reliability and the robustness of the proposed correlation function in the case of model errors are tested with reference to 2D and 3D benchmark case studies. A measure of the quality of the obtained sensor configuration is considered through the use of independent assessment criteria. In conclusion, the results obtained by applying the proposed procedure on a real 5-spans steel footbridge are described. The proposed method also allows to better estimate higher modes when the number of sensors is greater than the number of modes of interest. In addition, the results show a smaller variation in the sensor position when uncertainties occur.

Complications of intra-cardial placement of silastic central venous catheter in pediatric patients.

PubMed

Soong, W J; Jeng, M J; Hwang, B

1996-01-01

A three-year prospective study was undertaken to determine the incidence and early complications from intra-cardiac placement of percutaneous central venous catheter (CVC). CVC was inserted by using "Catheter-through-needle" technique, and the insertion length was measured by body surface landmark. CVC course and tip location were routinely checked by roentgenography. Echocardiography was performed in case of arrhythmia. After analysis of 784 CVCs, 104 (13.3%) were proved to be intra-cardial, as located by either roentgenography or echocardiography. However, catheters passed via the upper trunk (14.5%) were significantly (p < 0.05) more intra-cardially located than those via the lower trunk (4.8%). Catheters which passed via the right upper trunk veins (basilic, cephalic, or external jugular veins) were also more intra-cardially located than those via their left veins counterparts, but the finding was not statistically significant (p > 0.05). The mean body weight (3.1 +/- 2.4 kg) in the intra-cardial placement group was significantly (p < 0.05) less than that in the non-intracardial placement group (7.9 +/- 4.5 kg). In intra-cardial placement patients, 32 cases (30.8%) had episode(s) of cardiac arrhythmia including 31 premature ventricular depolarization and 1 supra-ventricular tachycardia. All cases showed the presence of intra-ventricular catheter. All arrhythmias ceased abruptly after the catheters were pulled from the hearts. No other early complications were observed. the incidence of the intracardiac placement of CVC is high, especially in small infants or when the insertion via the upper trunk. Short term intra-cardiac catheter placement has a benign clinical course except that the intraventricular catheter may cause arrhythmia. However, this kind of arrhythmia can be resolved spontaneously by withdrawing the catheter.

Pulmonary Intraparenchymal Blood Patching Decreases the Rate of Pneumothorax-Related Complications following Percutaneous CT-Guided Needle Biopsy.

PubMed

Graffy, Peter; Loomis, Scott B; Pickhardt, Perry J; Lubner, Meghan G; Kitchin, Douglas R; Lee, Fred T; Hinshaw, J Louis

2017-04-01

To investigate whether an autologous intraparenchymal blood patch (IPB) reduces the rate of pneumothorax-related complications associated with computed tomography (CT)-guided lung biopsies. This study included 834 patients: 482 who received an IPB and 352 who did not. Retrospective review was performed of all CT-guided lung biopsies performed at a single institution between August 2006 and September 2013. Patients were excluded if no aerated lung was crossed. The rate of pneumothorax, any associated intervention (eg, catheter placement, aspiration), chest tube placement, and chest tube replacement requiring hospital admission were compared by linear and multiple regression analysis. Patients who received an IPB had a significantly lower rate of pneumothorax (145 of 482 [30%] vs 154 of 352 [44%]; P < .0001), pneumothorax-related intervention (eg, catheter aspiration, pleural blood patch, chest tube placement; 43 of 482 [8.9%] vs 85 of 352 [24.1%]; P < .0001), and chest tube placement along with other determinants requiring hospital admission (18 of 482 [3.7%] vs 27 of 352 [7.7%]; P < .0001). No complications related to the IPB were noted in the study group. Autologous IPB placement is associated with a decreased rate of pneumothorax and associated interventions, including chest tube placement and hospital admission, after CT-guided lung biopsies, with no evidence of any adverse effects. These results suggest that an IPB is safe and effective and should be considered when aerated lung is traversed while performing a CT-guided lung biopsy. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

Resuscitation in massive obstetric haemorrhage using an intraosseous needle.

PubMed

Chatterjee, D J; Bukunola, B; Samuels, T L; Induruwage, L; Uncles, D R

2011-04-01

A 38-year-old woman experienced a massive postpartum haemorrhage 30 minutes after emergency caesarean delivery. The patient became severely haemodynamically compromised with an unrecordable blood pressure. Rapid fluid resuscitation was limited by the capacity of the intravenous cannula in place at the time and inability to establish additional vascular access using conventional routes in a timely manner. An intraosseous needle was inserted in the proximal humerus at the first attempt and administration of resuscitation fluid by this route subsequently enabled successful placement of further intravenous lines. Blood and blood products were deployed in conjunction with intra-operative cell salvage and transoesophageal Doppler cardiac output monitoring was used to assess adequacy of volume replacement. Haemorrhage control was finally achieved with the use of recombinant factor VIIa and hysterectomy. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

Percutaneous foot joint needle placement using a C-arm flat-panel detector CT.

PubMed

Wiewiorski, Martin; Takes, Martin Thanh Long; Valderrabano, Victor; Jacob, Augustinus Ludwig

2012-03-01

Image guidance is valuable for diagnostic injections in foot orthopaedics. Flat-detector computed tomography (FD-CT) was implemented using a C-arm, and the system was tested for needle guidance in foot joint injections. FD-CT-guided joint infiltration was performed in 6 patients referred from the orthopaedic department for diagnostic foot injections. All interventions were performed utilising a flat-panel fluoroscopy system utilising specialised image guidance and planning software. Successful infiltration was defined by localisation of contrast media depot in the targeted joint. The pre- and post-interventional numeric analogue scale (NAS) pain score was assessed. All injections were technically successful. Contrast media deposit was documented in all targeted joints. Significant relief of symptoms was noted by all 6 participants. FD-CT-guided joint infiltration is a feasible method for diagnostic infiltration of midfoot and hindfoot joints. The FD-CT approach may become an alternative to commonly used 2D-fluoroscopically guidance.

Assistive technology for ultrasound-guided central venous catheter placement.

PubMed

Ikhsan, Mohammad; Tan, Kok Kiong; Putra, Andi Sudjana

2018-01-01

This study evaluated the existing technology used to improve the safety and ease of ultrasound-guided central venous catheterization. Electronic database searches were conducted in Scopus, IEEE, Google Patents, and relevant conference databases (SPIE, MICCAI, and IEEE conferences) for related articles on assistive technology for ultrasound-guided central venous catheterization. A total of 89 articles were examined and pointed to several fields that are currently the focus of improvements to ultrasound-guided procedures. These include improving needle visualization, needle guides and localization technology, image processing algorithms to enhance and segment important features within the ultrasound image, robotic assistance using probe-mounted manipulators, and improving procedure ergonomics through in situ projections of important information. Probe-mounted robotic manipulators provide a promising avenue for assistive technology developed for freehand ultrasound-guided percutaneous procedures. However, there is currently a lack of clinical trials to validate the effectiveness of these devices.

Severe pruritus and myoclonus following intrathecal morphine administration in a dog

PubMed Central

Iff, Isabelle; Valeskini, Karin; Mosing, Martina

2012-01-01

During epidural needle placement in a 32-kg dog the subarachnoid space was punctured and half the intended dose of lidocaine, bupivacaine, and morphine was injected. After recovery from anesthesia the dog showed signs of severe pruritus of the tail base and limbs and myoclonus of the tail and hind limbs. Methadone, acepromazine, ketamine, buprenorphine, and butorphanol were administered to control myoclonus and pruritus, but were unsuccessful. Diazepam was used to control myoclonus until the effects of morphine abated. PMID:23450863

Common Algorithms of Primary Stress Placement on Polysyllabic Words

ERIC Educational Resources Information Center

Yurtbasi, Metin

2017-01-01

Turkish students tend to make considerable stress placement errors when pronouncing English polysyllabic words because of the interference of the traditional word stress patterns of their mother tongue. They usually misplace stresses in their utterance, both either as a result of their native pronunciation habits or their lack of stress-placing…

Metastatic renal cell carcinoma: CT-guided immunotherapy as a technically feasible and safe approach to delivery of gene therapy for treatment.

PubMed

Suh, Robert D; Goldin, Jonathan G; Wallace, Amanda B; Sheehan, Ramon E; Heinze, Stefan B; Gitlitz, Barbara J; Figlin, Robert A

2004-05-01

To assess the technical feasibility and safety of weekly outpatient percutaneous computed tomographic (CT)-guided intratumoral injections of interleukin-2 (IL-2) plasmid DNA in a wide variety of superficial and deep tumor sites. Twenty-nine patients with metastatic renal cell carcinoma and a total of 30 lesions measuring 1.0 cm(2) or greater in accessible thoracic (n = 15) or abdominal (n = 15) locations underwent up to three cycles of six weekly intratumoral IL-2 plasmid DNA injections. CT was used to guide needle placement and injection. After injection cycle 1, patients whose tumors demonstrated stable (< or =25% increase and < or =50% decrease in product of lesion diameters) or decreased size (>50% decrease in product of lesion diameters) advanced to injection cycle 2. Patients whose lesions decreased in size by more than 50% over the course of injection cycle 2 were eligible to begin injection cycle 3. An acceptable safety and technical feasibility profile for this technique was deemed to be (a) a safety and feasibility profile similar to that of single-needle biopsy and (b) an absence of serious adverse events (as defined in Title 21 of the Code of Federal Regulations) and/or unacceptable toxicities (as graded according to the National Cancer Institute Common Toxicity Criteria). A total of 284 intratumoral injections were performed, with a mean of 9.8 injections (range, 6-18 injections) received by each patient. Technical success (needle placement and injection of gene therapy agent) was achieved in all cases. Complications were experienced after 42 (14.8%) of the 284 injections. The most common complication was pneumothorax (at 32 [28.6%] of 112 intrathoracic injections), for which only one patient required catheter drainage. Complications occurred randomly throughout injection cycles and did not appear to increase as patients received more injections (P =.532). No patient experienced serious adverse events or unacceptable toxicities. Percutaneous CT-guided intratumoral immunotherapy injections are technically feasible and can be safely performed.

Retrospective analysis of technical success rate and procedure-related complications of 867 percutaneous CT-guided needle biopsies of lung lesions.

PubMed

Mills, M; Choi, J; El-Haddad, G; Sweeney, J; Biebel, B; Robinson, L; Antonia, S; Kumar, A; Kis, B

2017-12-01

To investigate the technical success rate and procedure-related complications of computed tomography (CT)-guided needle biopsy of lung lesions and to identify the factors that are correlated with the occurrence of procedure-related complications. This was a single- institution retrospective study of 867 consecutive CT-guided needle biopsies of lung lesions performed on 772 patients in a tertiary cancer centre. The technical success rate and complications were correlated with patient, lung lesion, and procedure-related variables. The technical success rate was 87.2% and the mortality rate was 0.12%. Of the 867 total biopsies 25.7% were associated with pneumothorax, and 6.5% required chest tube drainage. The haemothorax rate was 1.8%. There was positive correlation between the development of pneumothorax and smaller lesion diameter (p<0.001), longer transparenchymal distance (p<0.001), and prone position (p=0.027). There was positive correlation between the need for chest tube placement and longer transparenchymal distance (p=0.007) and smaller lesion diameter (p=0.018). Lesions in the left lower lobe had the lowest rates of pneumothorax (p=0.008) and chest tube drainage (p=0.018). Patients whose pneumothoraces were diagnosed on the follow-up chest X-ray, but not on the immediate post-procedural CT scan had significantly higher requirement for chest tube drainage (p=0.039). CT-guided lung biopsy has a high rate of technical success and a low rate of major complications. The present study has revealed several variables that can be used to identify high-risk procedures. A post-procedural chest X-ray within hours after the procedure is highly recommended to identify high-risk patients who require chest tube placement. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Mechanically assisted 3D ultrasound for pre-operative assessment and guiding percutaneous treatment of focal liver tumors

NASA Astrophysics Data System (ADS)

Sadeghi Neshat, Hamid; Bax, Jeffery; Barker, Kevin; Gardi, Lori; Chedalavada, Jason; Kakani, Nirmal; Fenster, Aaron

2014-03-01

Image-guided percutaneous ablation is the standard treatment for focal liver tumors deemed inoperable and is commonly used to maintain eligibility for patients on transplant waitlists. Radiofrequency (RFA), microwave (MWA) and cryoablation technologies are all delivered via one or a number of needle-shaped probes inserted directly into the tumor. Planning is mostly based on contrast CT/MRI. While intra-procedural CT is commonly used to confirm the intended probe placement, 2D ultrasound (US) remains the main, and in some centers the only imaging modality used for needle guidance. Corresponding intraoperative 2D US with planning and other intra-procedural imaging modalities is essential for accurate needle placement. However, identification of matching features of interest among these images is often challenging given the limited field-of-view (FOV) and low quality of 2D US images. We have developed a passive tracking arm with a motorized scan-head and software tools to improve guiding capabilities of conventional US by large FOV 3D US scans that provides more anatomical landmarks that can facilitate registration of US with both planning and intra-procedural images. The tracker arm is used to scan the whole liver with a high geometrical accuracy that facilitates multi-modality landmark based image registration. Software tools are provided to assist with the segmentation of the ablation probes and tumors, find the 2D view that best shows the probe(s) from a 3D US image, and to identify the corresponding image from planning CT scans. In this paper, evaluation results from laboratory testing and a phase 1 clinical trial for planning and guiding RFA and MWA procedures using the developed system will be presented. Early clinical results show a comparable performance to intra-procedural CT that suggests 3D US as a cost-effective alternative with no side-effects in centers where CT is not available.

CASPER: computer-aided segmentation of imperceptible motion-a learning-based tracking of an invisible needle in ultrasound.

PubMed

Beigi, Parmida; Rohling, Robert; Salcudean, Septimiu E; Ng, Gary C

2017-11-01

This paper presents a new micro-motion-based approach to track a needle in ultrasound images captured by a handheld transducer. We propose a novel learning-based framework to track a handheld needle by detecting microscale variations of motion dynamics over time. The current state of the art on using motion analysis for needle detection uses absolute motion and hence work well only when the transducer is static. We have introduced and evaluated novel spatiotemporal and spectral features, obtained from the phase image, in a self-supervised tracking framework to improve the detection accuracy in the subsequent frames using incremental training. Our proposed tracking method involves volumetric feature selection and differential flow analysis to incorporate the neighboring pixels and mitigate the effects of the subtle tremor motion of a handheld transducer. To evaluate the detection accuracy, the method is tested on porcine tissue in-vivo, during the needle insertion in the biceps femoris muscle. Experimental results show the mean, standard deviation and root-mean-square errors of [Formula: see text], [Formula: see text] and [Formula: see text] in the insertion angle, and 0.82, 1.21, 1.47 mm, in the needle tip, respectively. Compared to the appearance-based detection approaches, the proposed method is especially suitable for needles with ultrasonic characteristics that are imperceptible in the static image and to the naked eye.

SU-F-P-42: “To Navigate, Or Not to Navigate: HDR BT in Recurrent Spine Lesions”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voros, L; Cohen, G; Zaider, M

Purpose: We compare the accuracy of HDR catheter placement for paraspinal lesions using O-arm CBCT imaging combined with StealthStation navigation and traditional fluoroscopically guided catheter placement. Methods: CT and MRI scans were acquired pre-treatment to outline the lesions and design treatment plans (pre-plans) to meet dosimetric constrains. The pre-planned catheter trajectories were transferred into the StealthStation Navigation system prior to the surgery. The StealthStation is an infra red (IR) optical navigation system used for guidance of surgical instruments. An intraoperative CBCT scan (O-arm) was acquired with reference IR optical fiducials anchored onto the patient and registered with the preplan imagemore » study to guide surgical instruments in relation to the patients’ anatomy and to place the brachytherapy catheters along the pre-planned trajectories. The final treatment plan was generated based on a 2nd intraoperative CBCT scan reflecting achieved implant geometry. The 2nd CBCT was later registered with the initial CT scan to compare the preplanned dwell positions with actual dwell positions (catheter placements). Similar workflow was used in placement of 8 catheters (1 patient) without navigation, but under fluoroscopy guidance in an interventional radiology suite. Results: A total of 18 catheters (3 patients) were placed using navigation assisted surgery. Average displacement of 0.66 cm (STD=0.37cm) was observed between the pre-plan source positions and actual source positions in the 3 dimensional space. This translates into an average 0.38 cm positioning error in one direction including registration errors, digitization errors, and the surgeons ability to follow the planned trajectory. In comparison, average displacement of non-navigated catheters was 0.50 cm (STD=0.22cm). Conclusion: Spinal lesion HDR brachytherapy planning is a difficult task. Catheter placement has a direct impact on target coverage and dose to critical structures. While limited to a handful of patients, our experience shows navigation and fluoroscopy guided placement yield similar results.« less

Graduate Students' Administration and Scoring Errors on the Woodcock-Johnson III Tests of Cognitive Abilities

ERIC Educational Resources Information Center

Ramos, Erica; Alfonso, Vincent C.; Schermerhorn, Susan M.

2009-01-01

The interpretation of cognitive test scores often leads to decisions concerning the diagnosis, educational placement, and types of interventions used for children. Therefore, it is important that practitioners administer and score cognitive tests without error. This study assesses the frequency and types of examiner errors that occur during the…

Peripheral Quantitative Computed Tomography: Measurement Sensitivity in Persons With and Without Spinal Cord Injury

PubMed Central

Shields, Richard K.; Dudley-Javoroski, Shauna; Boaldin, Kathryn M.; Corey, Trent A.; Fog, Daniel B.; Ruen, Jacquelyn M.

2012-01-01

Objectives To determine (1) the error attributable to external tibia-length measurements by using peripheral quantitative computed tomography (pQCT) and (2) the effect these errors have on scan location and tibia trabecular bone mineral density (BMD) after spinal cord injury (SCI). Design Blinded comparison and criterion standard in matched cohorts. Setting Primary care university hospital. Participants Eight able-bodied subjects underwent tibia length measurement. A separate cohort of 7 men with SCI and 7 able-bodied age-matched male controls underwent pQCT analysis. Interventions Not applicable. Main Outcome Measures The projected worst-case tibia-length–measurement error translated into a pQCT slice placement error of ±3mm. We collected pQCT slices at the distal 4% tibia site, 3mm proximal and 3mm distal to that site, and then quantified BMD error attributable to slice placement. Results Absolute BMD error was greater for able-bodied than for SCI subjects (5.87mg/cm3 vs 4.5mg/cm3). However, the percentage error in BMD was larger for SCI than able-bodied subjects (4.56% vs 2.23%). Conclusions During cross-sectional studies of various populations, BMD differences up to 5% may be attributable to variation in limb-length–measurement error. PMID:17023249

Prevalence of Complications in Intraoperative Magnetic Resonance Imaging Combined with Neurophysiologic Monitoring.

PubMed

Sarnthein, Johannes; Lüchinger, Roger; Piccirelli, Marco; Regli, Luca; Bozinov, Oliver

2016-09-01

High-field intraoperative magnetic resonance imaging (ioMRI) is becoming increasingly available in neurosurgery centers, where it has to be combined with intraoperative neurophysiologic monitoring (IONM). IONM needle electrodes remain on the patient during ioMRI and may cause image distortions and burns. We tested magnetic resonance (MR) -heating experimentally and investigated the prevalence of complications. We studied electrodes that are certified for IONM, but not "MR conditional." They consist of copper cables (length, 1.5 m) and needles made of either stainless steel (ferromagnetic) or paramagnetic platinum/iridium alloy. We simulated an ioMRI session with gel and measured the temperature increase with optical fibers. We measured the force that an electrode experiences in the magnetic field. Between 2013 and 2016, we prospectively documented subcutaneous needle electrodes that remained in the patient during intraoperative 3 Tesla ioMRI scans. The in vitro testing of the electrodes produced a maximum heating (ΔT = 3.9°C) and force of 0.026 N. We placed 1237 subcutaneous needles in 57 surgical procedures with combined IONM and ioMRI, where needles remained in place during ioMRI. One patient suffered a skin burn on the shoulder. All other electrodes had no side effects. We have corroborated the history of safe use for electrodes with 1.5 m cable in a 3T MRI scanner and demonstrated their use. Nevertheless, heating cannot be excluded, as it depends on location and cable placement. When leaving electrodes in place during ioMRI, risks and benefits have to be carefully evaluated for each patient. Copyright © 2016 Elsevier Inc. All rights reserved.

Needle placement for piriformis injection using 3-D imaging.

PubMed

Clendenen, Steven R; Candler, Shawn A; Osborne, Michael D; Palmer, Scott C; Duench, Stephanie; Glynn, Laura; Ghazi, Salim M

2013-01-01

Piriformis syndrome is a pain syndrome originating in the buttock and is attributed to 6% - 8% of patients referred for the treatment of back and leg pain. The treatment for piriformis syndrome using fluoroscopy, computed tomography (CT), electromyography (EMG), and ultrasound (US) has become standard practice. The treatment of Piriformis Syndrome has evolved to include fluoroscopy and EMG with CT guidance. We present a case study of 5 successful piriformis injections using 3-D computer-assisted electromagnet needle tracking coupled with ultrasound. A 6-degree of freedom electromagnetic position tracker was attached to the ultrasound probe that allowed the system to detect the position and orientation of the probe in the magnetic field. The tracked ultrasound probe was used to find the posterior superior iliac spine. Subsequently, 3 points were captured to register the ultrasound image with the CT or magnetic resonance image scan. Moreover, after the registration was obtained, the navigation system visualized the tracked needle relative to the CT scan in real-time using 2 orthogonal multi-planar reconstructions centered at the tracked needle tip. Conversely, a recent study revealed that fluoroscopically guided injections had 30% accuracy compared to ultrasound guided injections, which tripled the accuracy percentage. This novel technique exhibited an accurate needle guidance injection precision of 98% while advancing to the piriformis muscle and avoiding the sciatic nerve. The mean (± SD) procedure time was 19.08 (± 4.9) minutes. This technique allows for electromagnetic instrument tip tracking with real-time 3-D guidance to the selected target. As with any new technique, a learning curve is expected; however, this technique could offer an alternative, minimizing radiation exposure.

Design and optimization of a brachytherapy robot

NASA Astrophysics Data System (ADS)

Meltsner, Michael A.

Trans-rectal ultrasound guided (TRUS) low dose rate (LDR) interstitial brachytherapy has become a popular procedure for the treatment of prostate cancer, the most common type of non-skin cancer among men. The current TRUS technique of LDR implantation may result in less than ideal coverage of the tumor with increased risk of negative response such as rectal toxicity and urinary retention. This technique is limited by the skill of the physician performing the implant, the accuracy of needle localization, and the inherent weaknesses of the procedure itself. The treatment may require 100 or more sources and 25 needles, compounding the inaccuracy of the needle localization procedure. A robot designed for prostate brachytherapy may increase the accuracy of needle placement while minimizing the effect of physician technique in the TRUS procedure. Furthermore, a robot may improve associated toxicities by utilizing angled insertions and freeing implantations from constraints applied by the 0.5 cm-spaced template used in the TRUS method. Within our group, Lin et al. have designed a new type of LDR source. The "directional" source is a seed designed to be partially shielded. Thus, a directional, or anisotropic, source does not emit radiation in all directions. The source can be oriented to irradiate cancerous tissues while sparing normal ones. This type of source necessitates a new, highly accurate method for localization in 6 degrees of freedom. A robot is the best way to accomplish this task accurately. The following presentation of work describes the invention and optimization of a new prostate brachytherapy robot that fulfills these goals. Furthermore, some research has been dedicated to the use of the robot to perform needle insertion tasks (brachytherapy, biopsy, RF ablation, etc.) in nearly any other soft tissue in the body. This can be accomplished with the robot combined with automatic, magnetic tracking.

Sci-Thur PM – Brachytherapy 02: Positional accuracy in Pd-103 permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederick, Amy; Watt, Elizabeth; Peacock, Michael

Purpose: This retrospective study aims to quantify the positional accuracy of seed delivery in permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC). Methods: Treatment planning and post-implant CT scans for 5 patients were rigidly registered using the MIM Symphony™ software (MIM Software, Cleveland, OH) and used to evaluate differences between planned and implanted seed positions. Total and directional seed displacements were calculated for each patient in a clinically relevant ‘needle coordinate system’, defined relative to the angle of fiducial needle insertion. Results: The overall average total seed displacement was 10±8 mm. Systematic seed displacements weremore » observed in individual patients and the magnitude and direction of these offsets varied among patients. One patient showed a significant directional seed displacement in the shallow-deep direction compared with the other four patients. With the exception of this one patient outlier, no significant systematic directional displacements in the needle coordinate system were observed for this cohort; the average directional displacements were −1±5 mm, 2±3 mm, and −2±4 mm in the shallow-deep, up-down, and right-left directions respectively. Conclusion: With the exception of one patient outlier, the magnitude of seed displacements were relatively consistent among patients. The results indicate that the shallow-deep direction possesses the largest uncertainty for the seed delivery method used at the TBCC. The relatively large uncertainty in seed placement in this direction is expected, as this is the direction of needle insertion. Further work will involve evaluating deflections of delivered needle tracks from their planned positions.« less

True incidence and clinical significance of pneumoperitoneum after PEG placement: a prospective study.

PubMed

Wiesen, Ari J; Sideridis, Kostas; Fernandes, Angelo; Hines, Jonathan; Indaram, Anant; Weinstein, Lenny; Davidoff, Samuel; Bank, Simmy

2006-12-01

PEG is a widely used method for providing nutritional support. Although pneumoperitoneum is a known finding after PEG placement, its true incidence is subject to debate. Small retrospective studies have found varied rates of free air after PEG placement. There were a total of 65 patients. To assess the true incidence of pneumoperitoneum and its clinical significance. Prospective study. Long Island Jewish Medical Center. We obtained upright and anterior-posterior chest radiographs of 65 patients within 3 hours after PEG placement. Type of PEG tube, gauge of the needle used, number of sticks, and indications were recorded. The presence of pneumoperitoneum on the initial chest film was considered to be a positive finding. After a positive result, a repeat chest film was obtained 72 hours later to determine whether there was progression or resolution of the free air. Patients enrolled in the study were also monitored clinically for evidence of peritonitis. Of the 65 patients who underwent PEG placement, 13 developed a pneumoperitoneum on the initial chest radiograph; there was complete resolution of pneumoperitoneum at 72 hours in 10 of the 13 patients. In 3 patients, the free air persisted but was of no clinical significance. The free air was quantified by measuring the height of the air column under the diaphragm and was graded with a scoring system (0, no air; 1, small; 2, moderate; 3, large). Eleven patients who underwent PEG died during the hospitalization; none of the deaths were related to the PEG placement or pneumoperitoneum. The other 54 patients were discharged to a skilled nursing facility. No patients in the study had clinical evidence of peritonitis. There were no adverse events, ie, infection or bleeding, associated with the PEG placement in any of the patients. Our data suggest that pneumoperitoneum after PEG placement is common and, in the absence of clinical symptoms, is of no clinical significance and does not warrant any further intervention.

A novel semi-robotized device for high-precision 18F-FDG-guided breast cancer biopsy.

PubMed

Hellingman, D; Teixeira, S C; Donswijk, M L; Rijkhorst, E J; Moliner, L; Alamo, J; Loo, C E; Valdés Olmos, R A; Stokkel, M P M

To assess the 3D geometric sampling accuracy of a new PET-guided system for breast cancer biopsy (BCB) from areas within the tumour with high 18 F-FDG uptake. In the context of the European Union project MammoCare, a prototype semi-robotic stereotactic prototype BCB-device was incorporated into a dedicated high resolution PET-detector for breast imaging. The system consists of 2 stacked rings, each containing 12 plane detectors, forming a dodecagon with a 186mm aperture for 3D reconstruction (1mm 3 voxel). A vacuum-assisted biopsy needle attached to a robot-controlled arm was used. To test the accuracy of needle placement, the needle tip was labelled with 18 F-FDG and positioned at 78 target coordinates distributed over a 35mm×24mm×28mm volume within the PET-detector field-of-view. At each position images were acquired from which the needle positioning accuracy was calculated. Additionally, phantom-based biopsy proofs, as well as MammoCare images of 5 breast cancer patients, were evaluated for the 3D automated locating of 18 F-FDG uptake areas within the tumour. Needle positioning tests revealed an average accuracy of 0.5mm (range 0-1mm), 0.6mm (range 0-2mm), and 0.4mm (range 0-2mm) for the x/y/z-axes, respectively. Furthermore, the MammoCare system was able to visualize and locate small (<10mm) regions with high 18 F-FDG uptake within the tumour suitable for PET-guided biopsy after being located by the 3D automated application. Accuracy testing demonstrated high-precision of this semi-automatic 3D PET-guided system for breast cancer core needle biopsy. Its clinical feasibility evaluation in breast cancer patients scheduled for neo-adjuvant chemotherapy will follow. Copyright © 2016 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Unicompartmental knee arthroplasty: is robotic technology more accurate than conventional technique?

PubMed

Citak, Mustafa; Suero, Eduardo M; Citak, Musa; Dunbar, Nicholas J; Branch, Sharon H; Conditt, Michael A; Banks, Scott A; Pearle, Andrew D

2013-08-01

Robotic-assisted unicompartmental knee arthroplasty (UKA) with rigid bone fixation "can significantly improve implant placement and leg alignment. The aim of this cadaveric study was to determine whether the use of robotic systems with dynamic bone tracking would provide more accurate UKA implant positioning compared to the conventional manual technique. Three-dimensional CT-based preoperative plans were created to determine the desired position and orientation for the tibial and femoral components. For each pair of cadaver knees, UKA was performed using traditional instrumentation on the left side and using a haptic robotic system on the right side. Postoperative CT scans were obtained and 3D-to-3D iterative closest point registration was performed. Implant position and orientation were compared to the preoperative plan. Surgical RMS errors for femoral component placement were within 1.9 mm and 3.7° in all directions of the planned implant position for the robotic group, while RMS errors for the manual group were within 5.4mm and 10.2°. Average RMS errors for tibial component placement were within 1.4mm and 5.0° in all directions for the robotic group; while, for the manual group, RMS errors were within 5.7 mm and 19.2°. UKA was more precise using a semiactive robotic system with dynamic bone tracking technology compared to the manual technique. Copyright © 2012 Elsevier B.V. All rights reserved.

Ultrasound criteria and guided fine-needle aspiration diagnostic yields in small animal peritoneal, mesenteric and omental disease.

PubMed

Feeney, Daniel A; Ober, Christopher P; Snyder, Laura A; Hill, Sara A; Jessen, Carl R

2013-01-01

Peritoneal, mesenteric, and omental diseases are important causes of morbidity and mortality in humans and animals, although information in the veterinary literature is limited. The purposes of this retrospective study were to determine whether objectively applied ultrasound interpretive criteria are statistically useful in differentiating among cytologically defined normal, inflammatory, and neoplastic peritoneal conditions in dogs and cats. A second goal was to determine the cytologically interpretable yield on ultrasound-guided, fine-needle sampling of peritoneal, mesenteric, or omental structures. Sonographic criteria agreed upon by the authors were retrospectively and independently applied by two radiologists to the available ultrasound images without knowledge of the cytologic diagnosis and statistically compared to the ultrasound-guided, fine-needle aspiration cytologic interpretations. A total of 72 dogs and 49 cats with abdominal peritoneal, mesenteric, or omental (peritoneal) surface or effusive disease and 17 dogs and 3 cats with no cytologic evidence of inflammation or neoplasia were included. The optimized, ultrasound criteria-based statistical model created independently for each radiologist yielded an equation-based diagnostic category placement accuracy of 63.2-69.9% across the two involved radiologists. Regional organ-associated masses or nodules as well as aggregated bowel and peritoneal thickening were more associated with peritoneal neoplasia whereas localized, severely complex fluid collections were more associated with inflammatory peritoneal disease. The cytologically interpretable yield for ultrasound-guided fine-needle sampling was 72.3% with no difference between species, making this a worthwhile clinical procedure. © 2013 Veterinary Radiology & Ultrasound.

Real-time visualization of ultrasound-guided retrobulbar blockade: an imaging study.

PubMed

Luyet, C; Eichenberger, U; Moriggl, B; Remonda, L; Greif, R

2008-12-01

Retrobulbar anaesthesia allows eye surgery in awake patients. Severe complications of the blind techniques are reported. Ultrasound-guided needle introduction and direct visualization of the spread of local anaesthetic may improve quality and safety of retrobulbar anaesthesia. Therefore, we developed a new ultrasound-guided technique using human cadavers. In total, 20 blocks on both sides in 10 embalmed human cadavers were performed. Using a small curved array transducer and a long-axis approach, a 22 G short bevel needle was introduced under ultrasound guidance lateral and caudal of the eyeball until the needle tip was seen 2 mm away from the optic nerve. At this point, 2 ml of contrast dye as a substitute for local anaesthetic was injected. Immediately after the injection, the spread of the contrast dye was documented by means of CT scans performed in each cadaver. The CT scans showed the distribution of the contrast dye in the muscle cone and behind the posterior sclera in all but one case. No contrast dye was found inside the optic nerve or inside the eyeball. In one case, there could be an additional trace of contrast dye behind the orbita. Our new ultrasound-guided technique has the potential to improve safety and efficacy of the procedure by direct visualization of the needle placement and the distribution of the injected fluid. Furthermore, the precise injection near the optic nerve could lead to a reduction of the amount of the local anaesthetic needed with fewer related complications.

The first clinical application of planning software for laparoscopic microwave thermosphere ablation of malignant liver tumours

PubMed Central

Berber, Eren

2015-01-01

Background Liver tumour ablation is an operator-dependent procedure. The determination of the optimum needle trajectory and correct ablation parameters could be challenging. The aim of this study was to report the utility of a new, procedure planning software for microwave ablation (MWA) of liver tumours. Methods This was a feasibility study in a pilot group of five patients with nine metastatic liver tumours who underwent laparoscopic MWA. Pre-operatively, parameters predicting the desired ablation zones were calculated for each tumour. Intra-operatively, this planning strategy was followed for both antenna placement and energy application. Post-operative 2-week computed tomography (CT) scans were performed to evaluate complete tumour destruction. Results The patients had an average of two tumours (range 1–4), measuring 1.9 ± 0.4 cm (range 0.9–4.4 cm). The ablation time was 7.1 ± 1.3 min (range 2.5–10 min) at 100W. There were no complications or mortality. The patients were discharged home on post-operative day (POD) 1. At 2-week CT scans, there were no residual tumours, with a complete ablation demonstrated in all lesions. Conclusions This study describes and validates pre-treatment planning software for MWA of liver tumours. This software was found useful to determine precisely the ablation parameters and needle placement to create a predicted zone of ablation. PMID:25980481

Diagnostic Lumbar Puncture

PubMed Central

Doherty, Carolynne M; Forbes, Raeburn B

2014-01-01

Diagnostic Lumbar Puncture is one of the most commonly performed invasive tests in clinical medicine. Evaluation of an acute headache and investigation of inflammatory or infectious disease of the nervous system are the most common indications. Serious complications are rare, and correct technique will minimise diagnostic error and maximise patient comfort. We review the technique of diagnostic Lumbar Puncture including anatomy, needle selection, needle insertion, measurement of opening pressure, Cerebrospinal Fluid (CSF) specimen handling and after care. We also make some quality improvement suggestions for those designing services incorporating diagnostic Lumbar Puncture. PMID:25075138

Two-layer critical dimensions and overlay process window characterization and improvement in full-chip computational lithography

NASA Astrophysics Data System (ADS)

Sturtevant, John L.; Liubich, Vlad; Gupta, Rachit

2016-04-01

Edge placement error (EPE) was a term initially introduced to describe the difference between predicted pattern contour edge and the design target for a single design layer. Strictly speaking, this quantity is not directly measurable in the fab. What is of vital importance is the relative edge placement errors between different design layers, and in the era of multipatterning, the different constituent mask sublayers for a single design layer. The critical dimensions (CD) and overlay between two layers can be measured in the fab, and there has always been a strong emphasis on control of overlay between design layers. The progress in this realm has been remarkable, accelerated in part at least by the proliferation of multipatterning, which reduces the available overlay budget by introducing a coupling of overlay and CD errors for the target layer. Computational lithography makes possible the full-chip assessment of two-layer edge to edge distances and two-layer contact overlap area. We will investigate examples of via-metal model-based analysis of CD and overlay errors. We will investigate both single patterning and double patterning. For single patterning, we show the advantage of contour-to-contour simulation over contour to target simulation, and how the addition of aberrations in the optical models can provide a more realistic CD-overlay process window (PW) for edge placement errors. For double patterning, the interaction of 4-layer CD and overlay errors is very complex, but we illustrate that not only can full-chip verification identify potential two-layer hotspots, the optical proximity correction engine can act to mitigate such hotspots and enlarge the joint CD-overlay PW.

Accuracy and Repeatability of Trajectory Rod Measurement Using Laser Scanners.

PubMed

Liscio, Eugene; Guryn, Helen; Stoewner, Daniella

2017-12-22

Three-dimensional (3D) technologies contribute greatly to bullet trajectory analysis and shooting reconstruction. There are few papers which address the errors associated with utilizing laser scanning for bullet trajectory documentation. This study examined the accuracy and precision of laser scanning for documenting trajectory rods in drywall for angles between 25° and 90°. The inherent error range of 0.02°-2.10° was noted while the overall error for laser scanning ranged between 0.04° and 1.98°. The inter- and intraobserver errors for trajectory rod placement and virtual trajectory marking showed that the range of variation for rod placement was between 0.1°-1° in drywall and 0.05°-0.5° in plywood. Virtual trajectory marking accuracy tests showed that 75% of data values were below 0.91° and 0.61° on azimuth and vertical angles, respectively. In conclusion, many contributing factors affect bullet trajectory analysis, and the use of 3D technologies can aid in reduction of errors associated with documentation. © 2017 American Academy of Forensic Sciences.

SU-F-T-20: Novel Catheter Lumen Recognition Algorithm for Rapid Digitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dise, J; McDonald, D; Ashenafi, M

Purpose: Manual catheter recognition remains a time-consuming aspect of high-dose-rate brachytherapy (HDR) treatment planning. In this work, a novel catheter lumen recognition algorithm was created for accurate and rapid digitization. Methods: MatLab v8.5 was used to create the catheter recognition algorithm. Initially, the algorithm searches the patient CT dataset using an intensity based k-means filter designed to locate catheters. Once the catheters have been located, seed points are manually selected to initialize digitization of each catheter. From each seed point, the algorithm searches locally in order to automatically digitize the remaining catheter. This digitization is accomplished by finding pixels withmore » similar image curvature and divergence parameters compared to the seed pixel. Newly digitized pixels are treated as new seed positions, and hessian image analysis is used to direct the algorithm toward neighboring catheter pixels, and to make the algorithm insensitive to adjacent catheters that are unresolvable on CT, air pockets, and high Z artifacts. The algorithm was tested using 11 HDR treatment plans, including the Syed template, tandem and ovoid applicator, and multi-catheter lung brachytherapy. Digitization error was calculated by comparing manually determined catheter positions to those determined by the algorithm. Results: he digitization error was 0.23 mm ± 0.14 mm axially and 0.62 mm ± 0.13 mm longitudinally at the tip. The time of digitization, following initial seed placement was less than 1 second per catheter. The maximum total time required to digitize all tested applicators was 4 minutes (Syed template with 15 needles). Conclusion: This algorithm successfully digitizes HDR catheters for a variety of applicators with or without CT markers. The minimal axial error demonstrates the accuracy of the algorithm, and its insensitivity to image artifacts and challenging catheter positioning. Future work to automatically place initial seed positions would improve the algorithm speed.« less

Longitudinal changes in femur bone mineral density after spinal cord injury: effects of slice placement and peel method

PubMed Central

Dudley-Javoroski, S.

2010-01-01

Summary Surveillance of femur metaphysis bone mineral density (BMD) decline after spinal cord injury (SCI) may be subject to slice placement error of 2.5%. Adaptations to anti-osteoporosis measures should exceed this potential source of error. Image analysis parameters likewise affect BMD output and should be selected strategically in longitudinal studies. Introduction Understanding the longitudinal changes in bone mineral density (BMD) after spinal cord injury (SCI) is important when assessing new interventions. We determined the longitudinal effect of SCI on BMD of the femur metaphysis. To facilitate interpretation of longitudinal outcomes, we (1) determined the BMD difference associated with erroneous peripheral quantitative computed tomography (pQCT) slice placement, and (2) determined the effect of operator-selected pQCT peel algorithms on BMD. Methods pQCT images were obtained from the femur metaphysis (12% of length from distal end) of adult subjects with and without SCI. Slice placement errors were simulated at 3 mm intervals and were processed in two ways (threshold-based vs. concentric peel). Results BMD demonstrated a rapid decline over 2 years post-injury. BMD differences attributable to operator-selected peel methods were large (17.3% for subjects with SCI). Conclusions Femur metaphysis BMD declines after SCI in a manner similar to other anatomic sites. Concentric (percentage-based) peel methods may be most appropriate when special sensitivity is required to detect BMD adaptations. Threshold-based methods may be more appropriate when asymmetric adaptations are observed. PMID:19707702

Design and evaluation of a computed tomography (CT)-compatible needle insertion device using an electromagnetic tracking system and CT images.

PubMed

Shahriari, Navid; Hekman, Edsko; Oudkerk, Matthijs; Misra, Sarthak

2015-11-01

Percutaneous needle insertion procedures are commonly used for diagnostic and therapeutic purposes. Although current technology allows accurate localization of lesions, they cannot yet be precisely targeted. Lung cancer is the most common cause of cancer-related death, and early detection reduces the mortality rate. Therefore, suspicious lesions are tested for diagnosis by performing needle biopsy. In this paper, we have presented a novel computed tomography (CT)-compatible needle insertion device (NID). The NID is used to steer a flexible needle (φ0.55 mm) with a bevel at the tip in biological tissue. CT images and an electromagnetic (EM) tracking system are used in two separate scenarios to track the needle tip in three-dimensional space during the procedure. Our system uses a control algorithm to steer the needle through a combination of insertion and minimal number of rotations. Noise analysis of CT images has demonstrated the compatibility of the device. The results for three experimental cases (case 1: open-loop control, case 2: closed-loop control using EM tracking system and case 3: closed-loop control using CT images) are presented. Each experimental case is performed five times, and average targeting errors are 2.86 ± 1.14, 1.11 ± 0.14 and 1.94 ± 0.63 mm for case 1, case 2 and case 3, respectively. The achieved results show that our device is CT-compatible and it is able to steer a bevel-tipped needle toward a target. We are able to use intermittent CT images and EM tracking data to control the needle path in a closed-loop manner. These results are promising and suggest that it is possible to accurately target the lesions in real clinical procedures in the future.

Recent advances in topical anesthesia

PubMed Central

2016-01-01

Topical anesthetics act on the peripheral nerves and reduce the sensation of pain at the site of application. In dentistry, they are used to control local pain caused by needling, placement of orthodontic bands, the vomiting reflex, oral mucositis, and rubber-dam clamp placement. Traditional topical anesthetics contain lidocaine or benzocaine as active ingredients and are used in the form of solutions, creams, gels, and sprays. Eutectic mixtures of local anesthesia cream, a mixture of various topical anesthetics, has been reported to be more potent than other anesthetics. Recently, new products with modified ingredients and application methods have been introduced into the market. These products may be used for mild pain during periodontal treatment, such as scaling. Dentists should be aware that topical anesthetics, although rare, might induce allergic reactions or side effects as a result of an overdose. Topical anesthetics are useful aids during dental treatment, as they reduce dental phobia, especially in children, by mitigating discomfort and pain. PMID:28879311

A simple method for long-term biliary access in large animals.

PubMed

Andrews, J C; Knutsen, C; Smith, P; Prieskorn, D; Crudip, J; Klevering, J; Ensminger, W D

1988-07-01

A simple method to obtain long-term access to the biliary tree in dogs and pigs is presented. In ten dogs and four pigs, a cholecystectomy was performed, the cystic duct isolated, and a catheter inserted into the cut end of the cystic duct. The catheter was connected to a subcutaneous infusion port, producing a closed, internal system to allow long-term access. The catheter placement was successful in three of the pigs and all of the dogs. Thirty-five cholangiograms were obtained in the 13 subjects by accessing the port with a 20 gauge Huber needle and injecting small amounts (4-10 mL) of contrast under fluoroscopic control. Cholangiograms were obtained up to four months after catheter placement without evidence for catheter failure or surgically induced changes in the biliary tree. This model provides a simple, reliable means to obtain serial cholangiograms in a research setting.

Holistic approach for overlay and edge placement error to meet the 5nm technology node requirements

NASA Astrophysics Data System (ADS)

Mulkens, Jan; Slachter, Bram; Kubis, Michael; Tel, Wim; Hinnen, Paul; Maslow, Mark; Dillen, Harm; Ma, Eric; Chou, Kevin; Liu, Xuedong; Ren, Weiming; Hu, Xuerang; Wang, Fei; Liu, Kevin

2018-03-01

In this paper, we discuss the metrology methods and error budget that describe the edge placement error (EPE). EPE quantifies the pattern fidelity of a device structure made in a multi-patterning scheme. Here the pattern is the result of a sequence of lithography and etching steps, and consequently the contour of the final pattern contains error sources of the different process steps. EPE is computed by combining optical and ebeam metrology data. We show that high NA optical scatterometer can be used to densely measure in device CD and overlay errors. Large field e-beam system enables massive CD metrology which is used to characterize the local CD error. Local CD distribution needs to be characterized beyond 6 sigma, and requires high throughput e-beam system. We present in this paper the first images of a multi-beam e-beam inspection system. We discuss our holistic patterning optimization approach to understand and minimize the EPE of the final pattern. As a use case, we evaluated a 5-nm logic patterning process based on Self-Aligned-QuadruplePatterning (SAQP) using ArF lithography, combined with line cut exposures using EUV lithography.

Initiation of labor analgesia with injection of local anesthetic through the epidural needle compared to the catheter

PubMed Central

Ristev, Goran; Sipes, Angela C; Mahoney, Bryan; Lipps, Jonathan; Chan, Gary; Coffman, John C

2017-01-01

Background The rationale for injection of epidural medications through the needle is to promote sooner onset of pain relief relative to dosing through the epidural catheter given that needle injection can be performed immediately after successful location of the epidural space. Some evidence indicates that dosing medications through the epidural needle results in faster onset and improved quality of epidural anesthesia compared to dosing through the catheter, though these dosing techniques have not been compared in laboring women. This investigation was performed to determine whether dosing medication through the epidural needle improves the quality of analgesia, level of sensory blockade, or onset of pain relief measured from the time of epidural medication injection. Methods In this double-blinded prospective investigation, healthy term laboring women (n=60) received labor epidural placement upon request. Epidural analgesia was initiated according to the assigned randomization group: 10 mL loading dose (0.125% bupivacaine with fentanyl 2 µg/mL) through either the epidural needle or the catheter, given in 5 mL increments spaced 2 minutes apart. Verbal rating scale (VRS) pain scores (0–10) and pinprick sensory levels were documented to determine the rates of analgesic and sensory blockade onset. Results No significant differences were observed in onset of analgesia or sensory blockade from the time of injection between study groups. The estimated difference in the rate of pain relief (VRS/minute) was 0.04 (95% CI: −0.01 to 0.11; p=0.109), and the estimated difference in onset of sensory blockade (sensory level/minute) was 0.63 (95% CI: −0.02 to 0.15; p=0.166). The time to VRS ≤3 and level of sensory block 20 minutes after dosing were also similar between groups. No differences in patient satisfaction, or maternal or fetal complications were observed. Conclusion This investigation observed that epidural needle and catheter injection of medications result in similar onset of analgesia and sensory blockade, quality of labor analgesia, patient satisfaction, and complication rates. PMID:29263693

Prostate Brachytherapy With Oblique Needles to Treat Large Glands and Overcome Pubic Arch Interference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, Bon; Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario; Bax, Jeff

2012-08-01

Purpose: First, to show that low-dose-rate prostate brachytherapy plans using oblique needle trajectories are more successful than parallel trajectories for large prostates with pubic arch interference (PAI); second, to test the accuracy of delivering an oblique plan by using a three-dimensional (3D) transrectal ultrasonography (TRUS)-guided mechatronic system. Methods and Materials: Prostates were contoured for 5 subjects' 3D TRUS images showing a maximum PAI of {<=}1 cm and a prostate volume of <50 cc. Two planning studies were done. First, prostate contours were artificially enlarged to 45 to 80 cc in 5- to 10-cc increments for a single subject. Second, allmore » subject prostate contours were enlarged to 60 cc. For each study, three types of plans were manually created for comparison: a parallel needle template (PT) plan, a parallel needle no-template (PNT) plan, and an oblique needle no-template (OBL) plan. Needle positions and angles were not discretized for nontemplate plans. European Society for Therapeutic Radiology and Oncology dose-volume histogram guidelines, iodine-125 (145-Gy prescription, 0.43 U), and needle angles of <15 Degree-Sign were used. An OBL plan was delivered to a pubic arch containing a 60-cc prostate phantom that mimicked the anatomy of the subject with the greatest PAI (23% by volume). Results: In the increasing-prostate volume study, OBL plans were successful for prostates of {<=}80 cc, and PT plans were successful for prostates of <65 cc. In paired, one-sided t tests for the 60-cc volume study, OBL plans showed dosimetric improvements for all organs compared to both of the parallel type plans (p < 0.05); PNT plans showed a benefit only in planning target volumes receiving more than 100 Gy compared to PT plans. A computed tomography scan of the phantom showed submillimeter seed placement accuracy in all directions. Conclusion: OBL plans were significantly better than parallel plans, and an OBL plan was accurately delivered to a 60-cc prostate phantom with 23% PAI by volume.« less

The reliability and validity of a portfolio designed as a programmatic assessment of performance in an integrated clinical placement.

PubMed

Roberts, Chris; Shadbolt, Narelle; Clark, Tyler; Simpson, Phillip

2014-09-20

Little is known about the technical adequacy of portfolios in reporting multiple complex academic and performance-based assessments. We explored, first, the influencing factors on the precision of scoring within a programmatic assessment of student learning outcomes within an integrated clinical placement. Second, the degree to which validity evidence supported interpretation of student scores. Within generalisability theory, we estimated the contribution that each wanted factor (i.e. student capability) and unwanted factors (e.g. the impact of assessors) made to the variation in portfolio task scores. Relative and absolute standard errors of measurement provided a confidence interval around a pre-determined pass/fail standard for all six tasks. Validity evidence was sought through demonstrating the internal consistency of the portfolio and exploring the relationship of student scores with clinical experience. The mean portfolio mark for 257 students, across 372 raters, based on six tasks, was 75.56 (SD, 6.68). For a single student on one assessment task, 11% of the variance in scores was due to true differences in student capability. The most significant interaction was context specificity (49%), the tendency for one student to engage with one task and not engage with another task. Rater subjectivity was 29%. An absolute standard error of measurement of 4.74%, gave a 95% CI of +/- 9.30%, and a 68% CI of +/- 4.74% around a pass/fail score of 57%. Construct validity was supported by demonstration of an assessment framework, the internal consistency of the portfolio tasks, and higher scores for students who did the clinical placement later in the academic year. A portfolio designed as a programmatic assessment of an integrated clinical placement has sufficient evidence of validity to support a specific interpretation of student scores around passing a clinical placement. It has modest precision in assessing students' achievement of a competency standard. There were identifiable areas for reducing measurement error and providing more certainty around decision-making. Reducing the measurement error would require engaging with the student body on the value of the tasks, more focussed academic and clinical supervisor training, and revisiting the rubric of the assessment in the light of feedback.

The ACUSITT ultrasonic ablator: the first steerable needle with an integrated interventional tool

NASA Astrophysics Data System (ADS)

Burdette, E. Clif; Rucker, D. Caleb; Prakash, Punit; Diederich, Chris J.; Croom, Jordon M.; Clarke, Clyde; Stolka, Philipp; Juang, Titania; Boctor, Emad M.; Webster, Robert J., III

2010-03-01

Steerability in percutaneous medical devices is highly desirable, enabling a needle or needle-like instrument to avoid sensitive structures (e.g. nerves or blood vessels), access obstructed anatomical targets, and compensate for the inevitable errors induced by registration accuracy thresholds and tissue deformation during insertion. Thus, mechanisms for needle steering have been of great interest in the engineering community in the past few years, and several have been proposed. While many interventional applications have been hypothesized for steerable needles (essentially anything deliverable via a regular needle), none have yet been demonstrated as far as the authors are aware. Instead, prior studies have focused on model validation, control, and accuracy assessment. In this paper, we present the first integrated steerable needle-interventional device. The ACUSITT integrates a multi-tube steerable Active Cannula (AC) with an Ultrasonic Interstitial Thermal Therapy ablator (USITT) to create a steerable percutaneous device that can deliver a spatially and temporally controllable (both mechanically and electronically) thermal dose profile. We present our initial experiments toward applying the ACUSITT to treat large liver tumors through a single entry point. This involves repositioning the ablator tip to several different locations, without withdrawing it from the liver capsule, under 3D Ultrasound image guidance. In our experiments, the ACUSITT was deployed to three positions, each 2cm apart in a conical pattern to demonstrate the feasibility of ablating large liver tumors 7cm in diameter without multiple parenchyma punctures.

[Method for evaluating the positional accuracy of a six-degrees-of-freedom radiotherapy couch using high definition digital cameras].

PubMed

Takemura, Akihiro; Ueda, Shinichi; Noto, Kimiya; Kurata, Yuichi; Shoji, Saori

2011-01-01

In this study, we proposed and evaluated a positional accuracy assessment method with two high-resolution digital cameras for add-on six-degrees-of-freedom radiotherapy (6D) couches. Two high resolution digital cameras (D5000, Nikon Co.) were used in this accuracy assessment method. These cameras were placed on two orthogonal axes of a linear accelerator (LINAC) coordinate system and focused on the isocenter of the LINAC. Pictures of a needle that was fixed on the 6D couch were taken by the cameras during couch motions of translation and rotation of each axis. The coordinates of the needle in the pictures were obtained using manual measurement, and the coordinate error of the needle was calculated. The accuracy of a HexaPOD evo (Elekta AB, Sweden) was evaluated using this method. All of the mean values of the X, Y, and Z coordinate errors in the translation tests were within ±0.1 mm. However, the standard deviation of the Z coordinate errors in the Z translation test was 0.24 mm, which is higher than the others. In the X rotation test, we found that the X coordinate of the rotational origin of the 6D couch was shifted. We proposed an accuracy assessment method for a 6D couch. The method was able to evaluate the accuracy of the motion of only the 6D couch and revealed the deviation of the origin of the couch rotation. This accuracy assessment method is effective for evaluating add-on 6D couch positioning.

AdVance male sling

PubMed Central

Chung, Amanda S. J.; Suarez, Oscar A.

2017-01-01

The AdVance sling (American Medical Systems, Minnetonka, MN, United States of America) is a synthetic transobturator sling, which is a safe and effective minimally invasive treatment for mild to moderate stress urinary incontinence (SUI) in male patients. This article provides a step-by-step description of our technique for placement of the AdVance male sling, including details and nuances gained from surgical experience, advice for avoidance of complications and discussion on management of complications and sling failures. Patient selection is very important, including exclusion and preoperative treatment of urethral stenosis and bladder dysfunction. Previous pelvic radiation is a poor prognostic factor. In brief, the steps of sling placement are: (I) mobilization of the corpus spongiosum (CS); (II) marking and mobilization of the central tendon; (III) passage of the helical trocar needles exiting at the apex of the angle between the CS and inferior pubic ramus; (IV) fixation of the broad part of the sling body to the CS at the previous mark; (V) cystoscopy during sling tensioning; (VI) placement of a Foley urethral catheter; (VII) Subcutaneous tunnelling of the sling arms back toward the midline; (VIII) wound closure. The most common early postoperative complication is urinary retention but long-term retention is extremely rare. Management of sling failures include placement of an artificial urinary sphincter, repeat AdVance sling, urethral bulking agent or ProACT device. PMID:28904900

The missed inferior alveolar block: a new look at an old problem.

PubMed

Milles, M

1984-01-01

A variation of a previously described technique to obtain mandibular block anesthesia is presented. This technique varies from those previously described in that is uses palpable anatomic landmarks, both extra- and intraoral, to orient the placement of the needle. This technique relies on several readily observed landmarks and the integration of these landmarks. Because palpable landmarks are used, consistent results can be easily obtained even in patients who present with a wide variety of anatomical variances which otherwise make this injection technique difficult and prone to failure.

Moving the Needle: Simulation's Impact on Patient Outcomes.

PubMed

Cox, Tiffany; Seymour, Neal; Stefanidis, Dimitrios

2015-08-01

This review investigates the available literature that addresses the impact simulator training has on patient outcomes. The authors conducted a comprehensive literature search of studies reporting outcomes of simulation training and categorized studies based on the Kirkpatrick model of training evaluation. Kirkpatrick level 4 studies reporting patient outcomes were identified and included in this review. Existing evidence is promising, demonstrating patient benefits as a result of simulation training for central line placement, obstetric emergencies, cataract surgery, laparoscopic inguinal hernia repair, and team training. Copyright © 2015 Elsevier Inc. All rights reserved.

Expanded polytetrafluoroethylene graft fistula for chronic hemodialysis.

PubMed

Tellis, V A; Kohlberg, W I; Bhat, D J; Driscoll, B; Veith, F J

1979-01-01

In a retrospective study of 66 PTFE arteriovenous fistulae and 71 BCH arteriovenous fistulae for dialysis access, PTFE had a higher patency rate than BCH at 12 months (62.4 versus 32.5%). PTFE was easier to work with and easier to handle in the face of infection. The lateral upper arm approach to placement of the PTFE graft is desirable in patients who have had multiple previous access procedures because this area is usually free from scarring, is distant from neurovascular structures, and provides a greater length of graft for needle punctures.

Augmented reality system for CT-guided interventions: system description and initial phantom trials

NASA Astrophysics Data System (ADS)

Sauer, Frank; Schoepf, Uwe J.; Khamene, Ali; Vogt, Sebastian; Das, Marco; Silverman, Stuart G.

2003-05-01

We are developing an augmented reality (AR) image guidance system, in which information derived from medical images is overlaid onto a video view of the patient. The interventionalist wears a head-mounted display (HMD) that presents him with the augmented stereo view. The HMD is custom fitted with two miniature color video cameras that capture the stereo view of the scene. A third video camera, operating in the near IR, is also attached to the HMD and is used for head tracking. The system achieves real-time performance of 30 frames per second. The graphics appears firmly anchored in the scne, without any noticeable swimming or jitter or time lag. For the application of CT-guided interventions, we extended our original prototype system to include tracking of a biopsy needle to which we attached a set of optical markers. The AR visualization provides very intuitive guidance for planning and placement of the needle and reduces radiation to patient and radiologist. We used an interventional abdominal phantom with simulated liver lesions to perform an inital set of experiments. The users were consistently able to locate the target lesion with the first needle pass. These results provide encouragement to move the system towards clinical trials.

A Novel Technique of Posterolateral Suturing in Thoracoscopic Diaphragmatic Hernia Repair

PubMed Central

Boo, Yoon Jung; Rohleder, Stephan; Muensterer, Oliver J.

2017-01-01

Background  Closure of the posterolateral defect in some cases of congenital diaphragmatic hernia (CDH) can be difficult. Percutaneous transcostal suturing is often helpful to create a complete, watertight closure of the diaphragm. A challenge with the technique is passing the needle out the same tract that it entered so that no skin is caught when the knots are laid down into the subcutaneous tissue. This report describes a novel technique using a Tuohy needle to percutaneously suture the posterolateral defect during thoracoscopic repair of CDH. Case  We report a case of a 6-week-old infant who presented with a CDH and ipsilateral intrathoracic kidney that was repaired using thoracoscopic approach. The posterolateral part of the defect was repaired by percutaneous transcostal suturing and extracorporeal knot tying. To assure correct placement of the sutures and knots, a Tuohy needle was used to guide the suture around the rib and out through the same subcutaneous tract. The total operative time was 145 minutes and there were no perioperative complications. The patient was followed up for 3 months, during which there was no recurrence. Conclusion  Our percutaneous Tuohy technique for closure of the posterolateral part of CDH enables a secure, rapid, and tensionless repair. PMID:28804698

A Novel Technique of Posterolateral Suturing in Thoracoscopic Diaphragmatic Hernia Repair.

PubMed

Boo, Yoon Jung; Rohleder, Stephan; Muensterer, Oliver J

2017-01-01

Background  Closure of the posterolateral defect in some cases of congenital diaphragmatic hernia (CDH) can be difficult. Percutaneous transcostal suturing is often helpful to create a complete, watertight closure of the diaphragm. A challenge with the technique is passing the needle out the same tract that it entered so that no skin is caught when the knots are laid down into the subcutaneous tissue. This report describes a novel technique using a Tuohy needle to percutaneously suture the posterolateral defect during thoracoscopic repair of CDH. Case  We report a case of a 6-week-old infant who presented with a CDH and ipsilateral intrathoracic kidney that was repaired using thoracoscopic approach. The posterolateral part of the defect was repaired by percutaneous transcostal suturing and extracorporeal knot tying. To assure correct placement of the sutures and knots, a Tuohy needle was used to guide the suture around the rib and out through the same subcutaneous tract. The total operative time was 145 minutes and there were no perioperative complications. The patient was followed up for 3 months, during which there was no recurrence. Conclusion  Our percutaneous Tuohy technique for closure of the posterolateral part of CDH enables a secure, rapid, and tensionless repair.

Comparison of technique errors of intraoral radiographs taken on film v photostimulable phosphor (PSP) plates.

PubMed

Zhang, Wenjian; Huynh, Carolyn P; Abramovitch, Kenneth; Leon, Inga-Lill K; Arvizu, Liliana

2012-06-01

The objective of this study was to compare the technical errors of intraoral radiographs exposed on film v photostimulable phosphor (PSP) plates. The intraoral radiographic images exposed on phantoms from preclinical practical exams of dental and dental hygiene students were used. Each exam consisted of 10 designated periapical and bitewing views. A total of 107 film sets and 122 PSP sets were evaluated for technique errors, including placement, elongation, foreshortening, overlapping, cone cut, receptor bending, density, mounting, dot in apical area, and others. Some errors were further subcategorized as minor, major, or remake depending on the severity. The percentages of radiographs with various errors were compared between film and PSP by the Fisher's Exact Test. Compared with film, there was significantly less PSP foreshortening, elongation, and bending errors, but significantly more placement and overlapping errors. Using a wrong sized receptor due to the similarity of the color of the package sleeves is a unique PSP error. Optimum image quality is attainable with PSP plates as well as film. When switching from film to a PSP digital environment, more emphasis is necessary for placing the PSP plates, especially those with excessive packet edge, and then correcting the corresponding angulation for the beam alignment. Better design for improving intraoral visibility and easy identification of different sized PSP will improve the clinician's technical performance with this receptor.

EUV local CDU healing performance and modeling capability towards 5nm node

NASA Astrophysics Data System (ADS)

Jee, Tae Kwon; Timoshkov, Vadim; Choi, Peter; Rio, David; Tsai, Yu-Cheng; Yaegashi, Hidetami; Koike, Kyohei; Fonseca, Carlos; Schoofs, Stijn

2017-10-01

Both local variability and optical proximity correction (OPC) errors are big contributors to the edge placement error (EPE) budget which is closely related to the device yield. The post-litho contact hole healing will be demonstrated to meet after-etch local variability specifications using a low dose, 30mJ/cm2 dose-to-size, positive tone developed (PTD) resist with relevant throughput in high volume manufacturing (HVM). The total local variability of the node 5nm (N5) contact holes will be characterized in terms of local CD uniformity (LCDU), local placement error (LPE), and contact edge roughness (CER) using a statistical methodology. The CD healing process has complex etch proximity effects, so the OPC prediction accuracy is challenging to meet EPE requirements for the N5. Thus, the prediction accuracy of an after-etch model will be investigated and discussed using ASML Tachyon OPC model.

Rewriting evolution--"been there, done that".

PubMed

Penny, David

2013-01-01

A recent paper by a science journalist in Nature shows major errors in understanding phylogenies, in this case of placental mammals. The underlying unrooted tree is probably correct, but the placement of the root just reflects a well-known error from the acceleration in the rate of evolution among some myomorph rodents.

Comparison of external catheters with subcutaneous vascular access ports for chronic vascular access in a porcine model.

PubMed

Chuang, Marc; Orvieto, Marcelo; Laven, Brett; Gerber, Glenn; Wardrip, Craig; Ritch, Chad; Shalhav, Arieh

2005-03-01

We sought to compare the outcomes of two chronic vascular access techniques, the externalized catheter and the subcutaneous vascular access port, in pigs. Female farm pigs (n = 30) underwent placement of a chronic vascular access device in the jugular vein for a research protocol: 18 of the animals underwent placement of a tunneled Hickman catheter (THC), and the remaining 12 animals underwent placement of a subcutaneous vascular access port (VAP) without external components. After placement of the devices, animals underwent serial blood sampling. All animals were given identical antibiotic prophylaxis. VAP access required the use of a restraint sling for Huber needle insertion, whereas THC access required no additional equipment. Animals were euthanatized 1 month after placement of the device. In the VAP group, the port was retrieved, cleaned, and steam-autoclaved for reuse. In the THC group, 13 (72%) animals developed infectious complications, and blood and wound cultures were often polymicrobial. One animal was euthanatized secondary to overwhelming sepsis. In addition, three (17%) animals developed thromboembolic complications. In contrast, no thromboembolic complications were noted in the VAP group, and only one animal developed a transient fever which resolved spontaneously; no septic complications or abscesses developed. Blood draws with no anesthesia were successful in both groups. We conclude that subcutaneous vascular access ports are a safe and efficient method for obtaining reliable chronic vascular access for a 1-month period in pigs. The subcutaneous devices were associated with low morbidity. In contrast, externalized catheters can be associated with considerable morbidity.

Advanced CD-SEM solution for edge placement error characterization of BEOL pitch 32nm metal layers

NASA Astrophysics Data System (ADS)

Charley, A.; Leray, P.; Lorusso, G.; Sutani, T.; Takemasa, Y.

2018-03-01

Metrology plays an important role in edge placement error (EPE) budgeting. Control for multi-patterning applications as new critical distances needs to be measured (edge to edge) and requirements become tighter and tighter in terms of accuracy and precision. In this paper we focus on imec iN7 BEOL platform and particularly on M2 patterning scheme using SAQP + block EUV for a 7.5 track logic design. Being able to characterize block to SAQP edge misplacement is important in a budgeting exercise (1) but is also extremely difficult due to challenging edge detection with CD-SEM (similar materials, thin layers, short distances, 3D features). In this study we develop an advanced solution to measure block to SAQP placement, we characterize it in terms of sensitivity, precision and accuracy through the comparison to reference metrology. In a second phase, the methodology is applied to budget local effects and the results are compared to the characterization of the SAQP and block independently.

A needle guidance system for biopsy and therapy using two-dimensional ultrasound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bluvol, Nathan; Sheikh, Allison; Kornecki, Anat

2008-02-15

Image-guided needle biopsies are currently used to provide a definitive diagnosis of breast cancer; however, difficulties in tumor targeting exist as the ultrasound (United States) scan plane and biopsy needle must remain coplanar throughout the procedure to display the actual needle tip position. The additional time associated with aligning and maintaining this coplanar relationship results in increased patient discomfort. Biopsy procedural efficiency is further hindered since needle pathway interpretation is often difficult, especially for needle insertions at large depths that usually require multiple reinsertions. The authors developed a system that would increase the speed and accuracy of current breast biopsymore » procedures using readily available two-dimensional (2D) US technology. This system is composed of a passive articulated mechanical arm that attaches to a 2D US transducer. The arm is connected to a computer through custom electronics and software, which were developed as an interface for tracking the positioning of the mechanical components in real time. The arm couples to the biopsy needle and provides visual guidance for the physician performing the procedure in the form of a real-time projected needle pathway overlay on an US image of the breast. An agar test phantom, with stainless steel targets interspersed randomly throughout, was used to validate needle trajectory positioning accuracy. The biopsy needle was guided by both the software and hardware components to the targets. The phantom, with the needle inserted and device decoupled, was placed in an x-ray stereotactic mammography (SM) machine. The needle trajectory and bead target locations were determined in three dimensions from the SM images. Results indicated a mean needle trajectory accuracy error of 0.75{+-}0.42 mm. This is adequate to sample lesions that are <2 mm in diameter. Chicken tissue test phantoms were used to compare core needle biopsy procedure times between experienced radiologists and inexperienced resident radiologists using free-hand US and the needle guidance system. Cylindrical polyvinyl alcohol cryogel lesions, colored blue, were embedded in chicken tissue. Radiologists identified the lesions, visible as hypoechoic masses in the US images, and performed biopsy using a 14-gauge needle. Procedure times were compared based on experience and the technique performed. Using a pair-wise t test, lower biopsy procedure times were observed when using the guidance system versus the free-hand technique (t=12.59, p<0.001). The authors believe that with this improved biopsy guidance they will be able to reduce the ''false negative'' rate of biopsies, especially in the hands of less experienced physicians.« less

Medical telementoring using an augmented reality transparent display.

PubMed

Andersen, Daniel; Popescu, Voicu; Cabrera, Maria Eugenia; Shanghavi, Aditya; Gomez, Gerardo; Marley, Sherri; Mullis, Brian; Wachs, Juan P

2016-06-01

The goal of this study was to design and implement a novel surgical telementoring system called the System for Telementoring with Augmented Reality (STAR) that uses a virtual transparent display to convey precise locations in the operating field to a trainee surgeon. This system was compared with a conventional system based on a telestrator for surgical instruction. A telementoring system was developed and evaluated in a study which used a 1 × 2 between-subjects design with telementoring system, that is, STAR or conventional, as the independent variable. The participants in the study were 20 premedical or medical students who had no prior experience with telementoring. Each participant completed a task of port placement and a task of abdominal incision under telementoring using either the STAR or the conventional system. The metrics used to test performance when using the system were placement error, number of focus shifts, and time to task completion. When compared with the conventional system, participants using STAR completed the 2 tasks with less placement error (45% and 68%) and with fewer focus shifts (86% and 44%), but more slowly (19% for each task). Using STAR resulted in decreased annotation placement error, fewer focus shifts, but greater times to task completion. STAR placed virtual annotations directly onto the trainee surgeon's field of view of the operating field by conveying location with great accuracy; this technology helped to avoid shifts in focus, decreased depth perception, and enabled fine-tuning execution of the task to match telementored instruction, but led to greater times to task completion. Copyright © 2016 Elsevier Inc. All rights reserved.

Articulatory Placement for /t/, /d/, /k/ and /g/ Targets in School Age Children with Speech Disorders Associated with Cleft Palate

ERIC Educational Resources Information Center

Gibbon, Fiona; Ellis, Lucy; Crampin, Lisa

2004-01-01

This study used electropalatography (EPG) to identify place of articulation for lingual plosive targets /t/, /d/, /k/ and /g/ in the speech of 15 school age children with repaired cleft palate. Perceptual judgements indicated that all children had correct velar placement for /k/, /g/ targets, but /t/, /d/ targets were produced as errors involving…

CT fluoroscopy-guided robotically-assisted lung biopsy

NASA Astrophysics Data System (ADS)

Xu, Sheng; Fichtinger, Gabor; Taylor, Russell H.; Banovac, Filip; Cleary, Kevin

2006-03-01

Lung biopsy is a common interventional radiology procedure. One of the difficulties in performing the lung biopsy is that lesions move with respiration. This paper presents a new robotically assisted lung biopsy system for CT fluoroscopy that can automatically compensate for the respiratory motion during the intervention. The system consists of a needle placement robot to hold the needle on the CT scan plane, a radiolucent Z-frame for registration of the CT and robot coordinate systems, and a frame grabber to obtain the CT fluoroscopy image in real-time. The CT fluoroscopy images are used to noninvasively track the motion of a pulmonary lesion in real-time. The position of the lesion in the images is automatically determined by the image processing software and the motion of the robot is controlled to compensate for the lesion motion. The system was validated under CT fluoroscopy using a respiratory motion simulator. A swine study was also done to show the feasibility of the technique in a respiring animal.

The Effect of 2 Injection Speeds on Local Anesthetic Discomfort During Inferior Alveolar Nerve Blocks.

PubMed

de Souza Melo, Marcelo Rodrigo; Sabey, Mark Jon Santana; Lima, Carla Juliane; de Almeida Souza, Liane Maciel; Groppo, Francisco Carlos

2015-01-01

This randomized double-blind crossover trial investigated the discomfort associated with 2 injection speeds, low (60 seconds) and slow (100 seconds), during inferior alveolar nerve block by using 1.8 mL of 2% lidocaine with 1 : 100,000 epinephrine. Three phases were considered: (a) mucosa perforation, (b) needle insertion, and (c) solution injection. Thirty-two healthy adult volunteers needing bilateral inferior alveolar nerve blocks at least 1 week apart were enrolled in the present study. The anesthetic procedure discomfort was recorded by volunteers on a 10-cm visual analog scale in each phase for both injection speeds. Comparison between the 2 anesthesia speeds in each phase was performed by paired t test. Results showed no statistically significant difference between injection speeds regarding perforation (P = .1016), needle placement (P = .0584), or speed injection (P = .1806). The discomfort in all phases was considered low. We concluded that the 2 injection speeds tested did not affect the volunteers' pain perception during inferior alveolar nerve blocks.

Evaluation of Phantom-Based Education System for Acupuncture Manipulation

PubMed Central

Lee, In-Seon; Lee, Ye-Seul; Park, Hi-Joon; Lee, Hyejung; Chae, Younbyoung

2015-01-01

Background Although acupuncture manipulation has been regarded as one of the important factors in clinical outcome, it has been difficult to train novice students to become skillful experts due to a lack of adequate educational program and tools. Objectives In the present study, we investigated whether newly developed phantom acupoint tools would be useful to practice-naïve acupuncture students for practicing the three different types of acupuncture manipulation to enhance their skills. Methods We recruited 12 novice students and had them practice acupuncture manipulations on the phantom acupoint (5% agarose gel). We used the Acusensor 2 and compared their acupuncture manipulation techniques, for which the target criteria were depth and time factors, at acupoint LI11 in the human body before and after 10 training sessions. The outcomes were depth of needle insertion, depth error from target criterion, time of rotating, lifting, and thrusting, time error from target criteria and the time ratio. Results After 10 training sessions, the students showed significantly improved outcomes in depth of needle, depth error (rotation, reducing lifting/thrusting), thumb-forward time error, thumb-backward time error (rotation), and lifting time (reinforcing lifting/thrusting). Conclusions The phantom acupoint tool could be useful in a phantom-based education program for acupuncture-manipulation training for students. For advanced education programs for acupuncture manipulation, we will need to collect additional information, such as patient responses, acupoint-specific anatomical characteristics, delicate tissue-like modeling, haptic and visual feedback, and data from an acupuncture practice simulator. PMID:25689598

Evaluation of phantom-based education system for acupuncture manipulation.

PubMed

Lee, In-Seon; Lee, Ye-Seul; Park, Hi-Joon; Lee, Hyejung; Chae, Younbyoung

2015-01-01

Although acupuncture manipulation has been regarded as one of the important factors in clinical outcome, it has been difficult to train novice students to become skillful experts due to a lack of adequate educational program and tools. In the present study, we investigated whether newly developed phantom acupoint tools would be useful to practice-naïve acupuncture students for practicing the three different types of acupuncture manipulation to enhance their skills. We recruited 12 novice students and had them practice acupuncture manipulations on the phantom acupoint (5% agarose gel). We used the Acusensor 2 and compared their acupuncture manipulation techniques, for which the target criteria were depth and time factors, at acupoint LI11 in the human body before and after 10 training sessions. The outcomes were depth of needle insertion, depth error from target criterion, time of rotating, lifting, and thrusting, time error from target criteria and the time ratio. After 10 training sessions, the students showed significantly improved outcomes in depth of needle, depth error (rotation, reducing lifting/thrusting), thumb-forward time error, thumb-backward time error (rotation), and lifting time (reinforcing lifting/thrusting). The phantom acupoint tool could be useful in a phantom-based education program for acupuncture-manipulation training for students. For advanced education programs for acupuncture manipulation, we will need to collect additional information, such as patient responses, acupoint-specific anatomical characteristics, delicate tissue-like modeling, haptic and visual feedback, and data from an acupuncture practice simulator.

Co-optimization of lithographic and patterning processes for improved EPE performance

NASA Astrophysics Data System (ADS)

Maslow, Mark J.; Timoshkov, Vadim; Kiers, Ton; Jee, Tae Kwon; de Loijer, Peter; Morikita, Shinya; Demand, Marc; Metz, Andrew W.; Okada, Soichiro; Kumar, Kaushik A.; Biesemans, Serge; Yaegashi, Hidetami; Di Lorenzo, Paolo; Bekaert, Joost P.; Mao, Ming; Beral, Christophe; Larivière, Stephane

2017-03-01

Complimentary lithography is already being used for advanced logic patterns. The tight pitches for 1D Metal layers are expected to be created using spacer based multiple patterning ArF-i exposures and the more complex cut/block patterns are made using EUV exposures. At the same time, control requirements of CDU, pattern shift and pitch-walk are approaching sub-nanometer levels to meet edge placement error (EPE) requirements. Local variability, such as Line Edge Roughness (LER), Local CDU, and Local Placement Error (LPE), are dominant factors in the total Edge Placement error budget. In the lithography process, improving the imaging contrast when printing the core pattern has been shown to improve the local variability. In the etch process, it has been shown that the fusion of atomic level etching and deposition can also improve these local variations. Co-optimization of lithography and etch processing is expected to further improve the performance over individual optimizations alone. To meet the scaling requirements and keep process complexity to a minimum, EUV is increasingly seen as the platform for delivering the exposures for both the grating and the cut/block patterns beyond N7. In this work, we evaluated the overlay and pattern fidelity of an EUV block printed in a negative tone resist on an ArF-i SAQP grating. High-order Overlay modeling and corrections during the exposure can reduce overlay error after development, a significant component of the total EPE. During etch, additional degrees of freedom are available to improve the pattern placement error in single layer processes. Process control of advanced pitch nanoscale-multi-patterning techniques as described above is exceedingly complicated in a high volume manufacturing environment. Incorporating potential patterning optimizations into both design and HVM controls for the lithography process is expected to bring a combined benefit over individual optimizations. In this work we will show the EPE performance improvement for a 32nm pitch SAQP + block patterned Metal 2 layer by cooptimizing the lithography and etch processes. Recommendations for further improvements and alternative processes will be given.

First Person Point of View Augmented Reality for Central Line Insertion Training: A Usability and Feasibility Study

PubMed Central

Rochlen, Lauryn R.; Levine, Robert; Tait, Alan R.

2016-01-01

Introduction The value of simulation in medical education and procedural skills training is well recognized. Despite this, many mannequin-based trainers are limited by the inability of the trainee to view the internal anatomical structures. This study evaluates the usability and feasibility of a 1st person point of view (POV) augmented reality (AR) trainer on needle insertion as a component of central venous catheter (CVC) placement. Methods Forty subjects, including medical students and anesthesiology residents and faculty participated. AR glasses were provided through which the relevant internal anatomical landmarks were projected. Following a practice period, participants were asked to place the needle in the mannequin without the benefit of the AR projected internal anatomy. The ability of the trainees to correctly place the needle was documented. Participants also completed a short survey describing their perceptions of the AR technology. Results Participants reported that the AR technology was realistic (77.5%) and that the ability to view the internal anatomy was helpful (92.5%). Furthermore, 85% and 82.1%, respectively, believed that the AR technology promoted learning and should be incorporated into medical training. The ability to successfully place the needle was similar between experienced and non-experienced participants, however, less experienced participants were more likely to inadvertently puncture the carotid artery. Conclusions Results of this pilot study demonstrated the usability and feasibility of AR technology as a potentially important adjunct to simulated medical skills training. Further development and evaluation of this innovative technology under a variety of simulated medical training settings would be an important next step. PMID:27930431

First-Person Point-of-View-Augmented Reality for Central Line Insertion Training: A Usability and Feasibility Study.

PubMed

Rochlen, Lauryn R; Levine, Robert; Tait, Alan R

2017-02-01

The value of simulation in medical education and procedural skills training is well recognized. Despite this, many mannequin-based trainers are limited by the inability of the trainee to view the internal anatomical structures. This study evaluates the usability and feasibility of a first-person point-of-view-augmented reality (AR) trainer on needle insertion as a component of central venous catheter placement. Forty subjects, including medical students and anesthesiology residents and faculty, participated. Augmented reality glasses were provided through which the relevant internal anatomical landmarks were projected. After a practice period, participants were asked to place the needle in the mannequin without the benefit of the AR-projected internal anatomy. The ability of the trainees to correctly place the needle was documented. Participants also completed a short survey describing their perceptions of the AR technology. Participants reported that the AR technology was realistic (77.5%) and that the ability to view the internal anatomy was helpful (92.5%). Furthermore, 85% and 82.1%, respectively, believed that the AR technology promoted learning and should be incorporated into medical training. The ability to successfully place the needle was similar between experienced and nonexperienced participants; however, less experienced participants were more likely to inadvertently puncture the carotid artery. Results of this pilot study demonstrated the usability and feasibility of AR technology as a potentially important adjunct to simulated medical skills training. Further development and evaluation of this innovative technology under a variety of simulated medical training settings would be an important next step.

Needle aspiration versus intercostal tube drainage for pneumothorax in the newborn.

PubMed

Bruschettini, Matteo; Romantsik, Olga; Ramenghi, Luca Antonio; Zappettini, Simona; O'Donnell, Colm P F; Calevo, Maria Grazia

2016-01-11

Pneumothorax occurs more frequently in the neonatal period than at any other time of life and is associated with increased mortality and morbidity. It may be treated with either needle aspiration or insertion of a chest tube. The former consists of aspiration of air with a syringe through a needle or an angiocatheter, usually through the second or third intercostal space in the midclavicular line. The chest tube is usually placed in the anterior pleural space passing through the sixth intercostal space into the pleural opening, turned anteriorly and directed to the location of the pneumothorax, and then connected to a Heimlich valve or an underwater seal with continuous suction. To compare the efficacy and safety of needle aspiration and intercostal tube drainage in the management of neonatal pneumothorax. We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 11), MEDLINE via PubMed (1966 to 30 November 2015), EMBASE (1980 to 30 November 2015), and CINAHL (1982 to 30 November 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing needle aspiration (either with the needle or angiocatheter left in situ or removed immediately after aspiration) to intercostal tube drainage in newborn infants with pneumothorax. For each of the included trial, two authors independently extracted data (e.g. number of participants, birth weight, gestational age, kind of needle and chest tube, choice of intercostal space, pressure and device for drainage) and assessed the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). The primary outcomes considered in this review are mortality during the neonatal period and during hospitalisation. One randomised controlled trial (72 infants) met the inclusion criteria of this review. We found no differences in the rates of mortality (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.27 to 8.45) or complications related to the procedure. After needle aspiration, the angiocatheter was left in situ (mean 27.1 hours) and not removed immediately after the aspiration. The angiocatheter was in place for a shorter duration than the intercostal tube (mean difference (MD) -11.20 hours, 95% CI -15.51 to -6.89). None of the 36 newborns treated with needle aspiration with the angiocatheter left in situ required the placement of an intercostal tube drainage. Overall, the quality of the evidence supporting this finding is low. At present there is insufficient evidence to determine the efficacy and safety of needle aspiration versus intercostal tube drainage in the management of neonatal pneumothorax. Randomised controlled trials comparing the two techniques are warranted.

Accuracy analysis of pedicle screw placement in posterior scoliosis surgery: comparison between conventional fluoroscopic and computer-assisted technique.

PubMed

Kotani, Yoshihisa; Abumi, Kuniyoshi; Ito, Manabu; Takahata, Masahiko; Sudo, Hideki; Ohshima, Shigeki; Minami, Akio

2007-06-15

The accuracy of pedicle screw placement was evaluated in posterior scoliosis surgeries with or without the use of computer-assisted surgical techniques. In this retrospective cohort study, the pedicle screw placement accuracy in posterior scoliosis surgery was compared between conventional fluoroscopic and computer-assisted surgical techniques. There has been no study systemically analyzing the perforation pattern and comparative accuracy of pedicle screw placement in posterior scoliosis surgery. The 45 patients who received posterior correction surgeries were divided into 2 groups: Group C, manual control (25 patients); and Group N, navigation surgery (20 patients). The average Cobb angles were 73.7 degrees and 73.1 degrees before surgery in Group C and Group N, respectively. Using CT images, vertebral rotation, pedicle axes as measured to anteroposterior sacral axis and vertebral axis, and insertion angle error were measured. In perforation cases, the angular tendency, insertion point, and length abnormality were evaluated. The perforation was observed in 11% of Group C and 1.8% in Group N. In Group C, medial perforations of left screws were demonstrated in 8 of 9 perforated screws and 55% were distributed either in L1 or T12. The perforation consistently occurred in pedicles in which those axes approached anteroposterior sacral axis within 5 degrees . The average insertion errors were 8.4 degrees and 5.0 degrees in Group C and Group N, respectively, which were significantly different (P < 0.02). The medial perforation in Group C occurred around L1, especially when pedicle axis approached anteroposterior sacral axis. This consistent tendency was considered as the limitation of fluoroscopic screw insertion in which horizontal vertebral image was not visible. The use of surgical navigation system successfully reduced the perforation rate and insertion angle errors, demonstrating the clear advantage in safe and accurate pedicle screw placement of scoliosis surgery.

Microwave ablation of pulmonary malignancies using a novel high-energy antenna system.

PubMed

Little, Mark W; Chung, Daniel; Boardman, Philip; Gleeson, Fergus V; Anderson, Ewan M

2013-04-01

To evaluate the technical success, safety, and imaging follow-up of malignant pulmonary nodules treated with a novel high-energy percutaneous microwave ablation (MWA) system. Between July 2010 and September 2011, a total of 23 patients, 12 men, mean age 68 (range 30-87) years with 29 pulmonary malignancies of median diameter 19 (range 8-57) mm, underwent computed tomography (CT)-guided MWA with a 16G microwave needle antenna enabling power up to 180 W. Technical success was defined as needle placement in the intended lesion without death or serious injury. Adequacy of ablation was assessed at 24 h on contrast-enhanced CT. Circumferential solid or ground glass opacification >5 mm was used to define an ideal ablation. Local tumor recurrence was assessed at 1, 3, and 6 months after ablation on contrast-enhanced CT. MWA was technically successful in 93 % (n = 27). Mean ablation duration was 3.6 (range 1-9) min. Ten patients (43 %) developed a pneumothorax as a result of the MWA; only 3 (13 %) required placement of a chest drain. Thirty-day mortality rate was 0 %. The mean hospital stay was 1.5 (range 1-7) days. A total of 22 lesions (75 %) were surrounded by ≥5 mm ground glass or solid opacification after the procedure. At a median follow-up of 6 months, local recurrence was identified in 3 out of 26 lesions, giving a local control rate of 88 %. MWA using a high-power antenna of pulmonary malignancies is safe, technically achievable, and enables fast ablation times.

Rewriting Evolution—“Been There, Done That”

PubMed Central

Penny, David

2013-01-01

A recent paper by a science journalist in Nature shows major errors in understanding phylogenies, in this case of placental mammals. The underlying unrooted tree is probably correct, but the placement of the root just reflects a well-known error from the acceleration in the rate of evolution among some myomorph rodents. PMID:23558594

Usefulness of intraoperative radiographs in reducing errors of cup placement and leg length during total hip arthroplasty.

PubMed

Wind, Michael A; Morrison, J Craig; Christie, Michael J

2013-11-01

Traditional methods of component placement during total hip arthroplasty (THA) can lead to errors in cup abduction angle and leg length. Intraoperative radiographs were used to assess and correct errors during surgery in a consecutive series of 278 THAs performed by a single surgeon. After exclusions, 262 cases were available for cup abduction angle assessment and 224 for leg length discrepancy (LLD) assessment. Components were initially placed in a position determined as appropriate by the surgeon. Intraoperative radiographs were taken and appropriate corrections made. Postoperative radiographs were assessed at 6 weeks. Mean abduction angle on intraoperative radiographs was 39.6°±5.9° versus 38.6°±4.1° on postoperative radiographs. Thirty-eight cups were outside the target abduction range on intraoperative radiographs versus 4 on postoperative radiographs. Mean LLD was 3.7 mm ± 3.6 mm on intraoperative radiographs and 2.5 mm ± 2.7 mm on postoperative radiographs. Use of intraoperative radiographs is a valid, useful technique for minimizing errors in THA.

Augmented Reality Visualization with Use of Image Overlay Technology for MR Imaging–guided Interventions: Assessment of Performance in Cadaveric Shoulder and Hip Arthrography at 1.5 T

PubMed Central

Fritz, Jan; U-Thainual, Paweena; Ungi, Tamas; Flammang, Aaron J.; Fichtinger, Gabor; Iordachita, Iulian I.

2012-01-01

Purpose: To prospectively assess overlay technology in providing accurate and efficient targeting for magnetic resonance (MR) imaging–guided shoulder and hip joint arthrography. Materials and Methods: A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imager. A total of 24 shoulder joint and 24 hip joint injections were planned in 12 human cadavers. Two operators (A and B) participated, each performing procedures on different cadavers using image overlay guidance. MR imaging was used to confirm needle positions, monitor injections, and perform MR arthrography. Accuracy was assessed according to the rate of needle adjustment, target error, and whether the injection was intraarticular. Efficiency was assessed according to arthrography procedural time. Operator differences were assessed with comparison of accuracy and procedure times between the operators. Mann-Whitney U test and Fisher exact test were used to assess group differences. Results: Forty-five arthrography procedures (23 shoulders, 22 hips) were performed. Three joints had prostheses and were excluded. Operator A performed 12 shoulder and 12 hip injections. Operator B performed 11 shoulder and 10 hip injections. Needle adjustment rate was 13% (six of 45; one for operator A and five for operator B). Target error was 3.1 mm ± 1.2 (standard deviation) (operator A, 2.9 mm ± 1.4; operator B, 3.5 mm ± 0.9). Intraarticular injection rate was 100% (45 of 45). The average arthrography time was 14 minutes (range, 6–27 minutes; 12 minutes [range, 6–25 minutes] for operator A and 16 minutes [range, 6–27 min] for operator B). Operator differences were not significant with regard to needle adjustment rate (P = .08), target error (P = .07), intraarticular injection rate (P > .99), and arthrography time (P = .22). Conclusion: Image overlay technology provides accurate and efficient MR guidance for successful shoulder and hip arthrography in human cadavers. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112640/-/DC1 PMID:22843764

Using a Motion Sensor-Equipped Smartphone to Facilitate CT-Guided Puncture.

PubMed

Hirata, Masaaki; Watanabe, Ryouhei; Koyano, Yasuhiro; Sugata, Shigenori; Takeda, Yukie; Nakamura, Seiji; Akamune, Akihisa; Tsuda, Takaharu; Mochizuki, Teruhito

2017-04-01

To demonstrate the use of "Smart Puncture," a smartphone application to assist conventional CT-guided puncture without CT fluoroscopy, and to describe the advantages of this application. A puncture guideline is displayed by entering the angle into the application. Regardless of the angle at which the device is being held, the motion sensor ensures that the guideline is displayed at the appropriate angle with respect to gravity. The angle of the smartphone's liquid crystal display (LCD) is also detected, preventing needle deflection from the CT slice image. Physicians can perform the puncture procedure by advancing the needle using the guideline while the smartphone is placed adjacent to the patient. In an experimental puncture test using a sponge as a target, the target was punctured at 30°, 50°, and 70° when the device was tilted to 0°, 15°, 30°, and 45°, respectively. The punctured target was then imaged with a CT scan, and the puncture error was measured. The mean puncture error in the plane parallel to the LCD was less than 2°, irrespective of device tilt. The mean puncture error in the sagittal plane was less than 3° with no device tilt. However, the mean puncture error tended to increase when the tilt was increased. This application can transform a smartphone into a valuable tool that is capable of objectively and accurately assisting CT-guided puncture procedures.

Triton Mosaic

NASA Image and Video Library

1999-08-25

Mosaic of Triton constructed from 16 individual images. After globally minimizing the camera pointing errors, the frames we reprocessed by map projections, photometric function removal and placement in the mosaic.

Wireless Mobile Technology to Improve Workflow and Feasibility of MR-Guided Percutaneous Interventions

PubMed Central

Rube, Martin A.; Holbrook, Andrew B.; Cox, Benjamin F.; Buciuc, Razvan; Melzer, Andreas

2015-01-01

Purpose A wireless interactive display and control device combined with a platform-independent web-based User Interface (UI) was developed to improve the workflow for interventional Magnetic Resonance Imaging (iMRI). Methods The iMRI-UI enables image acquisition of up to three independent slices using various pulse sequences with different contrast weighting. Pulse sequence, scan geometry and related parameters can be changed on the fly via the iMRI-UI using a tablet computer for improved lesion detection and interventional device targeting. The iMRI-UI was validated for core biopsies with a liver phantom (n=40) and Thiel soft-embalmed human cadavers (n=24) in a clinical 1.5T MRI scanner. Results The iMRI-UI components and setup were tested and found conditionally MRI-safe to use according to current ASTM standards. Despite minor temporary touchscreen interference at a close distance to the bore (<20 cm), no other issues regarding quality or imaging artefacts were observed. The 3D root-mean-square distance error was 2.8±1.0 (phantom) / 2.9±0.8 mm (cadaver) and overall procedure times ranged between 12–22 (phantom) / 20–55 minutes (cadaver). Conclusions The wireless iMRI-UI control setup enabled fast and accurate interventional biopsy needle placements along complex trajectories and improved the workflow for percutaneous interventions under MRI guidance in a preclinical trial. PMID:25179151

MO-G-17A-09: Quantitative Autoradiography of Biopsy Specimens Extracted Under PET/CT Guidance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanchon, L; Carlin, S; Schmidtlein, C

2014-06-15

Purpose: To develop a procedure for accurate determination of PET tracer concentration with high spatial accuracy in situ by performing Quantitative Autoradiography of Biopsy Specimens (QABS) extracted under PET/CT guidance. Methods: Autoradiography (ARG) standards were produced from a gel loaded with a known concentration of FDG biopsied with 18G and 20G biopsy needles. Specimens obtained with these needles are generally cylindrical: up to 18 mm in length and about 0.8 and 0.6 mm in diameter respectively. These standards, with similar shape and density as biopsy specimens were used to generate ARG calibration curves.Quantitative ARG was performed to measure the activitymore » concentration in biopsy specimens extracted from ten patients. The biopsy sites were determined according to PET/CT's obtained in the operating room. Additional CT scans were acquired with the needles in place to confirm correct needle placements. The ARG images were aligned with the needle tip in the PET/CT images using the open source CERR software. The mean SUV calculated from the specimen activities (SUVarg) were compared to that from PET (SUVpet) at the needle locations. Results: Calibration curves show that the relation between ARG signal and activity concentration in those standards is linear for the investigated range (up to 150 kBq/ml). The correlation coefficient of SUVarg with SUVpet is 0.74. Discrepancies between SUVarg and SUVpet can be attributed to the small size of the biopsy specimens compared to PET resolution. Conclusion: The calibration procedure using surrogate biopsy specimens provided a method for quantifying the activity within the biopsy cores obtained under FDG-PET guidance. QABS allows mapping the activity concentration in such biopsy specimens with a resolution of about 1mm. QABS is a promising tool for verification of biopsy adequacy by comparing specimen activity to that expected from the PET image. A portion of this research was funded by a research grant from Biospace Lab, 13 rue Georges Auric 75019 Paris, FRANCE.« less

Toward optical guidance during endoscopic ultrasound-guided fine needle aspirations of pancreatic masses using single fiber reflectance spectroscopy: a feasibility study

NASA Astrophysics Data System (ADS)

Stegehuis, Paulien L.; Boogerd, Leonora S. F.; Inderson, Akin; Veenendaal, Roeland A.; van Gerven, P.; Bonsing, Bert A.; Sven Mieog, J.; Amelink, Arjen; Veselic, Maud; Morreau, Hans; van de Velde, Cornelis J. H.; Lelieveldt, Boudewijn P. F.; Dijkstra, Jouke; Robinson, Dominic J.; Vahrmeijer, Alexander L.

2017-02-01

Endoscopic ultrasound-guided fine needle aspirations (EUS-FNA) of pancreatic masses suffer from sample errors and low-negative predictive values. Fiber-optic spectroscopy in the visible to near-infrared wavelength spectrum can noninvasively extract physiological parameters from tissue and has the potential to guide the sampling process and reduce sample errors. We assessed the feasibility of single fiber (SF) reflectance spectroscopy measurements during EUS-FNA of pancreatic masses and its ability to distinguish benign from malignant pancreatic tissue. A single optical fiber was placed inside a 19-gauge biopsy needle during EUS-FNA and at least three reflectance measurements were taken prior to FNA. Spectroscopy measurements did not cause any related adverse events and prolonged procedure time with ˜5 min. An accurate correlation between spectroscopy measurements and cytology could be made in nine patients (three benign and six malignant). The oxygen saturation and bilirubin concentration were significantly higher in benign tissue compared with malignant tissue (55% versus 21%, p=0.038; 166 μmol/L versus 17 μmol/L, p=0.039, respectively). To conclude, incorporation of SF spectroscopy during EUS-FNA was feasible, safe, and relatively quick to perform. The optical properties of benign and malignant pancreatic tissue are different, implying that SF spectroscopy can potentially guide the FNA sampling.

Sutured clear corneal incision: wound apposition and permeability to bacterial-sized particles.

PubMed

May, William N; Castro-Combs, Juan; Kashiwabuchi, Renata T; Tattiyakul, Woranart; Qureshi-Said, Saima; Hirai, Flavio; Behrens, Ashley

2013-03-01

To determine the effects of single radial or horizontal suture placement in 2-step clear corneal incision (CCI) wound apposition and permeability to particles of India ink. Five fresh human globes were included. Two 25-gauge needles connected to a saline solution bag and to a digital manometer were inserted through the limbus, 120 degrees apart from each other. Four 2-step CCIs (2.75 mm wide and 3 mm length) were constructed in each cornea. Incisions were divided into 3 groups: single radial suture (SRS), single horizontal suture (SHS), and unsutured group. Optical coherence tomography (OCT) was performed before and after suture placement. With a preset 10 mm Hg intraocular pressure (IOP), India ink was applied to the incision site and a standardized sudden IOP fluctuation was induced. OCT and superficial images were recorded before and after suture placement. India ink inflow and internal and external CCI gapping were outlined and measured by planimeter. The area and linear distance of India ink inflow after pressure challenge in all study groups were higher when compared with pre-pressure measurements; however, this increase was significant in the SRS and SHS groups (P < 0.05). Additionally, SRS placement significantly increased inner wound gapping (P = 0.018), and SHS significantly widened outer wound gape (P = 0.02). Well-constructed unsutured 2-step CCI seems to be more efficient at preventing bacterial-sized particles inflow during sudden changes in IOP, and it seems to offer better wound apposition as assessed by OCT.

Irreversible Electroporation of the Pancreas Using Parallel Plate Electrodes in a Porcine Model: A Feasibility Study.

PubMed

Rombouts, Steffi J E; Nijkamp, Maarten W; van Dijck, Willemijn P M; Brosens, Lodewijk A A; Konings, Maurits; van Hillegersberg, R; Borel Rinkes, Inne H M; Hagendoorn, Jeroen; Wittkampf, Fred H; Molenaar, I Quintus

2017-01-01

Irreversible electroporation (IRE) with needle electrodes is being explored as treatment option in locally advanced pancreatic cancer. Several studies have shown promising results with IRE needles, positioned around the tumor to achieve tumor ablation. Disadvantages are the technical difficulties for needle placement, the time needed to achieve tumor ablation, the risk of needle track seeding and most important the possible occurrence of postoperative pancreatic fistula via the needle tracks. The aim of this experimental study was to evaluate the feasibility of a new IRE-technique using two parallel plate electrodes, in a porcine model. Twelve healthy pigs underwent laparotomy. The pancreas was mobilized to enable positioning of the paddles. A standard monophasic external cardiac defibrillator was used to perform an ablation in 3 separate parts of the pancreas; either a single application of 50 or 100J or a serial application of 4x50J. After 6 hours, pancreatectomy was performed for histology and pigs were terminated. Histology showed necrosis of pancreatic parenchyma with neutrophil influx in 5/12, 11/12 and 12/12 of the ablated areas at 50, 100, and 4x50J respectively. The electric current density threshold to achieve necrosis was 4.3, 5.1 and 3.4 A/cm2 respectively. The ablation threshold was significantly lower for the serial compared to the single applications (p = 0.003). The content of the ablated areas differed between the applications: areas treated with a single application of 50 J often contained vital areas without obvious necrosis, whereas half of the sections treated with 100 J showed small islands of normal looking cells surrounded by necrosis, while all sections receiving 4x 50 J showed a homogeneous necrotic lesion. Pancreatic tissue can be successfully ablated using two parallel paddles around the tissue. A serial application of 4x50J was most effective in creating a homogeneous necrotic lesion.

Validity of the Omron HJ-112 pedometer during treadmill walking.

PubMed

Hasson, Rebecca E; Haller, Jeannie; Pober, David M; Staudenmayer, John; Freedson, Patty S

2009-04-01

The purpose of this investigation was to examine the validity of step counts measured with the Omron HJ-112 pedometer and to assess the effect of pedometer placement. Ninety-two subjects (44 males and 48 females; 71 with body mass index [BMI] <30 kg.m and 21 with BMI >or=30 kg.m) completed three, 12-min bouts of treadmill walking at speeds of 1.12, 1.34, and 1.56 mxs. A subset (21 males and 23 females; 38 BMI <30 kg.m and 6 BMI >or=30 kg.m) completed a variable walking condition. For all conditions, participants wore an Omron HJ-112 pedometer on the hip, in the pants pocket, in the chest shirt pocket, and around the neck. Hip pedometer placement was alternated between right and left sides with the Yamax Digiwalker SW-701. During each walk, an investigator recorded actual steps with a manual hand counter. There was no substantial bias with the Omron in any speed condition (-0.1% to 0.5%). Bias was larger with the Yamax (-3.6% to 2.0%). The largest random error for the Omron was 3.7% in the variable-speed condition for the BMI <30 kg.m group, whereas random errors for the Yamax were larger and up to 20%. None of the Omron placement positions produced statistically significant bias. Hip mounting produced the smallest random error (1.2%), followed by shirt pocket (1.7%), neck (2.2%), and pants pocket (5.8%). The Omron HJ-112 pedometer validly assesses steps in different BMI groups during constant- and variable-speed walking; other than that in the pants pocket, placement of the pedometer has little effect on validity.

Minimally invasive guidewireless, navigated pedicle screw placement: a technical report and case series.

PubMed

Smith, Brandon W; Joseph, Jacob R; Kirsch, Michael; Strasser, Mary Oakley; Smith, Jacob; Park, Paul

2017-08-01

OBJECTIVE Percutaneous pedicle screw insertion (PPSI) is a mainstay of minimally invasive spinal surgery. Traditionally, PPSI is a fluoroscopy-guided, multistep process involving traversing the pedicle with a Jamshidi needle, placement of a Kirschner wire (K-wire), placement of a soft-tissue dilator, pedicle tract tapping, and screw insertion over the K-wire. This study evaluates the accuracy and safety of PPSI with a simplified 2-step process using a navigated awl-tap followed by navigated screw insertion without use of a K-wire or fluoroscopy. METHODS Patients undergoing PPSI utilizing the K-wire-less technique were identified. Data were extracted from the electronic medical record. Complications associated with screw placement were recorded. Postoperative radiographs as well as CT were evaluated for accuracy of pedicle screw placement. RESULTS Thirty-six patients (18 male and 18 female) were included. The patients' mean age was 60.4 years (range 23.8-78.4 years), and their mean body mass index was 28.5 kg/m 2 (range 20.8-40.1 kg/m 2 ). A total of 238 pedicle screws were placed. A mean of 6.6 pedicle screws (range 4-14) were placed over a mean of 2.61 levels (range 1-7). No pedicle breaches were identified on review of postoperative radiographs. In a subgroup analysis of the 25 cases (69%) in which CT scans were performed, 173 screws were assessed; 170 (98.3%) were found to be completely within the pedicle, and 3 (1.7%) demonstrated medial breaches of less than 2 mm (Grade B). There were no complications related to PPSI in this cohort. CONCLUSIONS This streamlined 2-step K-wire-less, navigated PPSI appears safe and accurate and avoids the need for radiation exposure to surgeon and staff.

Expanded polytetrafluoroethylene graft fistula for chronic hemodialysis.

PubMed Central

Tellis, V A; Kohlberg, W I; Bhat, D J; Driscoll, B; Veith, F J

1979-01-01

In a retrospective study of 66 PTFE arteriovenous fistulae and 71 BCH arteriovenous fistulae for dialysis access, PTFE had a higher patency rate than BCH at 12 months (62.4 versus 32.5%). PTFE was easier to work with and easier to handle in the face of infection. The lateral upper arm approach to placement of the PTFE graft is desirable in patients who have had multiple previous access procedures because this area is usually free from scarring, is distant from neurovascular structures, and provides a greater length of graft for needle punctures. Images Fig. 3. PMID:758853

Design of the annular suspension and pointing system /ASPS/ through decoupling and pole placement. [for Space Shuttle

NASA Technical Reports Server (NTRS)

Kuo, B. C.; Lin, W. C. W.

1980-01-01

A decoupling and pole-placement technique has been developed for the Annular Suspension and Pointing System (ASPS) of the Space Shuttle which uses bandwidths as performance criteria. The dynamics of the continuous-data ASPS allows the three degrees of freedom to be totally decoupled by state feedback through constant gains, so that the bandwidth of each degree of freedom can be independently specified without interaction. Although it is found that the digital ASPS cannot be completely decoupled, the bandwidth requirements are satisfied by pole placement and a trial-and-error method based on approximate decoupling.

Hybrid reflection type metasurface of nano-antennas designed for optical needle field generation

NASA Astrophysics Data System (ADS)

Wang, Shiyi; Zhan, Qiwen

2015-03-01

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid optical antennas for comprehensive spatial engineering the properties of optical fields. Its capability is illustrated with an example to create a radially polarized vectorial beam for optical needle field generation. Functioning as local quarter-wave-plates (QWP), the MIM metasurface is designed to convert circularly polarized incident into local linear polarization to create an overall radial polarization with corresponding binary phases and desired normalized amplitude modulation ranged from 0.07 to 1. To obtain enough degrees of freedom, the optical-antenna layer comprises periodic arrangements of double metallic nano-bars with perpendicular placement and single nano-bars respectively for different amplitude modulation requirements. Both of the antennas enable to introduce π/2 retardation while reaching the desired modulation range both for phase and amplitude. Through adjusting the antennas' geometry and array carefully, we shift the gap-surface plasmon resonances facilitated by optical antennas to realize the manipulation of vectorial properties. Designed at 1064 nm wavelength, the particularly generated vectorial light output can be further tightly focused by a high numerical aperture objective to obtain longitudinally polarized flat-top focal field. The so-called optical needle field is a promising candidate for novel applications that transcend disciplinary boundaries. The proposed metasurface establishes a new class of compact optical components based on nano-scale structures, leading to compound functions for vectorial light generation.

Sharp Central Venous Recanalization in Hemodialysis Patients: A Single-Institution Experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arabi, Mohammad, E-mail: marabi2004@hotmail.com; Ahmed, Ishtiaq; Mat’hami, Abdulaziz

PurposeWe report our institutional experience with sharp central venous recanalization in chronic hemodialysis patients who failed standard techniques.Materials and MethodsSince January 2014, a series of seven consecutive patients (four males and three females), mean age 35 years (18–65 years), underwent sharp central venous recanalization. Indications included obtaining hemodialysis access (n = 6) and restoration of superior vena cava (SVC) patency to alleviate occlusion symptoms and restore fistula function (n = 1). The transseptal needle was used for sharp recanalization in six patients, while it could not be introduced in one patient due to total occlusion of the inferior vena cava. Instead, transmediastinal SVC access using Chibamore » needle was obtained.ResultsTechnical success was achieved in all cases. SVC recanalization achieved symptoms’ relief and restored fistula function in the symptomatic patient. One patient underwent arteriovenous fistula creation on the recanalized side 3 months after the procedure. The remaining catheters were functional at median follow-up time of 9 months (1–14 months). Two major complications occurred including a right hemothorax and a small hemopericardium, which were managed by covered stent placement across the perforated SVC.ConclusionSharp central venous recanalization using the transseptal needle is feasible technique in patients who failed standard recanalization procedures. The potential high risk of complications necessitates thorough awareness of anatomy and proper technical preparedness.« less

The efficacy of two electrodes radiofrequency technique: comparison study using a cadaveric interspinous ligament and temperature measurement using egg white.

PubMed

Lee, Chang-Hyung; Derby, Richard; Choi, Hyun-Seok; Lee, Sang-Heon; Kim, Se Hoon; Kang, Yoon Kyu

2010-01-01

One technique in radiofrequency neurotomies uses 2 electrodes that are simultaneously placed to lie parallel to one another. Comparing lesions on cadaveric interspinous ligament tissue and measuring the temperature change in egg white allows us to accurately measure quantitatively the area of the lesion. Fresh cadaver spinal tissue and egg white tissue were used. A series of samples were prepared with the electrodes placed 1 to 7 mm apart. Using radiofrequency, the needle electrodes were heated in sequential or simultaneous order and the distance of the escaped lesion area and temperature were measured. Samples of cadaver interspinous ligament showed sequential heating of the needles limits the placement of the needle electrodes up to 2 mm apart from each other and up to 4 mm apart when heated simultaneously. The temperature at the escaped lesion area decreased according to the distance for egg white. There was a significant difference in temperature at the escaped lesion area up to 6 mm apart and the temperature was above 50 degrees celsius up to 5 mm in simultaneous lesion and 3 mm in the sequential lesion. The limitations of this study include cadaveric experimentation and use of intraspinous ligament rather than medial branch of the dorsal ramus which is difficult to identify. Heating the 2 electrodes simultaneously appears to coagulate a wider area and potentially produce better results in less time.

A novel method for accurate needle-tip identification in trans-rectal ultrasound-based high-dose-rate prostate brachytherapy.

PubMed

Zheng, Dandan; Todor, Dorin A

2011-01-01

In real-time trans-rectal ultrasound (TRUS)-based high-dose-rate prostate brachytherapy, the accurate identification of needle-tip position is critical for treatment planning and delivery. Currently, needle-tip identification on ultrasound images can be subject to large uncertainty and errors because of ultrasound image quality and imaging artifacts. To address this problem, we developed a method based on physical measurements with simple and practical implementation to improve the accuracy and robustness of needle-tip identification. Our method uses measurements of the residual needle length and an off-line pre-established coordinate transformation factor, to calculate the needle-tip position on the TRUS images. The transformation factor was established through a one-time systematic set of measurements of the probe and template holder positions, applicable to all patients. To compare the accuracy and robustness of the proposed method and the conventional method (ultrasound detection), based on the gold-standard X-ray fluoroscopy, extensive measurements were conducted in water and gel phantoms. In water phantom, our method showed an average tip-detection accuracy of 0.7 mm compared with 1.6 mm of the conventional method. In gel phantom (more realistic and tissue-like), our method maintained its level of accuracy while the uncertainty of the conventional method was 3.4mm on average with maximum values of over 10mm because of imaging artifacts. A novel method based on simple physical measurements was developed to accurately detect the needle-tip position for TRUS-based high-dose-rate prostate brachytherapy. The method demonstrated much improved accuracy and robustness over the conventional method. Copyright © 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Effectiveness of different final irrigation techniques and placement of endodontic sealer into dentinal tubules.

PubMed

Oliveira, Kauhanna Vianna de; Silva, Bruno Marques da; Leonardi, Denise Piotto; Crozeta, Bruno Monguilhott; Sousa-Neto, Manoel Damião de; Baratto-Filho, Flares; Gabardo, Marilisa Carneiro Leão

2017-12-18

The aim of this study was to compare two irrigation techniques and four devices for endodontic sealer placement into the dentinal tubules. Ninety-nine single-rooted human teeth were instrumented and allocated to either the control (CO) (n=11) or experimental groups according to the irrigation method: syringe and NaveTip needle (NT) (n=44), and EndoActivator (EA) (n=44). These groups were subdivided according to sealer placement into K-File (KF), lentulo spiral (LS), Easy Clean (EC), and EndoActivator (EA) subgroups. Moreover, the distances of 5 mm and 2 mm from the apex were analyzed. The teeth were obturated with AH Plus and GuttaCore X3. Analyses were performed by scanning electron microscopy associated to cathodoluminescence. The percentage and maximum depth of sealer penetration were measured. Data were evaluated by three-way analysis of variance (ANOVA) and Games-Howell test (p<0.05). EA was superior to NT in percentage of sealer penetration. EC was significantly superior to EA (subgroup) for sealer penetration, and both improved the percentage of sealer penetration when compared to LS. Better sealer penetration was observed at the distance of 5 mm from the apex. Sealer penetration into the dentinal tubules was significantly improved by sonic irrigant activation.

Does unilateral hip flexion increase the spinal anaesthetic level during combined spinal–epidural technique?

PubMed Central

Mohta, Medha; Agarwal, Deepti; Sethi, AK

2011-01-01

Needle-through-needle combined spinal–epidural (CSE) may cause significant delay in patient positioning resulting in settling down of spinal anaesthetic and unacceptably low block level. Bilateral hip flexion has been shown to extend the spinal block by flattening lumbar lordosis. However, patients with lower limb fractures cannot flex their injured limb. This study was conducted to find out if unilateral hip flexion could extend the level of spinal anaesthesia following a prolonged CSE technique. Fifty American Society of Anesthesiologists (ASA) I/II males with unilateral femur fracture were randomly allocated to Control or Flexion groups. Needle-through-needle CSE was performed in the sitting position at L2-3 interspace and 2.6 ml 0.5% hyperbaric bupivacaine injected intrathecally. Patients were made supine 4 min after the spinal injection or later if epidural placement took longer. The Control group patients (n=25) lay supine with legs straight, whereas the Flexion group patients (n=25) had their uninjured hip and knee flexed for 5 min. Levels of sensory and motor blocks and time to epidural drug requirement were recorded. There was no significant difference in sensory levels at different time-points; maximum sensory and motor blocks; times to achieve maximum blocks; and time to epidural drug requirement in two groups. However, four patients in the Control group in contrast to none in the Flexion group required epidural drug before start of surgery. Moreover, in the Control group four patients took longer than 30 min to achieve maximum sensory block. To conclude, unilateral hip flexion did not extend the spinal anaesthetic level; however, further studies are required to explore the potential benefits of this technique. PMID:21808396

Usability evaluation of intradermal adapters (IDA).

PubMed

Tsals, Izrail

2017-03-27

Intradermal adapter device technology minimizes the complexity of the Mantoux technique, thereby providing predictable, reproducible intradermal (ID) injections and removing the concerns regarding the ease and reliability of Mantoux technique when using conventional needle and syringe. The technology employs a simple device with geometry designed to gently deform the skin surface and the subcutaneous tissue, providing the ideal angle and depth of needle insertion for consistently successful intradermal injections. The results of this development were presented at the First, Second and Third Skin Vaccination Summits in 2011, 2013 and 2015 respectively [1,2,3]. The current publication addresses the performance of intradermal adapters (IDA) evaluated in three preclinical studies. The evaluations were based on the assessment of bleb formation in a skin model, an accepted indicator of ID injection success. All evaluated devices share the same proprietary dermal interface technology. Devices instituting this design are easy to use, require minimal training, and employ conventionally molded parts and cannula. These studies evaluated IDAs of initial design integral with luer lock needles, IDAs for use with conventional syringes, and intradermal adapters for use with auto disable syringes (ADID adapters). The evaluated ID adapters were intended to consistently place the lancet of the needle at a depth of 0.75mm from the skin's surface. This placement depth addresses the variation in the skin thickness at immunization sites for the majority of patients independent of many other variables. Most participants preferred the intradermal adapter method over the traditional Mantoux and identified a need for the adapter at their workplace. Evaluation of IDAs by registered nurses indicated these devices increase success of bleb formation. The use of IDA increased the success of forming blebs by about 30%. Nurses felt the injections were much easier to perform, in particular by novices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of electrodes' placement and deformation in deep brain stimulation from medical images

NASA Astrophysics Data System (ADS)

Mehri, Maroua; Lalys, Florent; Maumet, Camille; Haegelen, Claire; Jannin, Pierre

2012-02-01

Deep brain stimulation (DBS) is used to reduce the motor symptoms such as rigidity or bradykinesia, in patients with Parkinson's disease (PD). The Subthalamic Nucleus (STN) has emerged as prime target of DBS in idiopathic PD. However, DBS surgery is a difficult procedure requiring the exact positioning of electrodes in the pre-operative selected targets. This positioning is usually planned using patients' pre-operative images, along with digital atlases, assuming that electrode's trajectory is linear. However, it has been demonstrated that anatomical brain deformations induce electrode's deformations resulting in errors in the intra-operative targeting stage. In order to meet the need of a higher degree of placement accuracy and to help constructing a computer-aided-placement tool, we studied the electrodes' deformation in regards to patients' clinical data (i.e., sex, mean PD duration and brain atrophy index). Firstly, we presented an automatic algorithm for the segmentation of electrode's axis from post-operative CT images, which aims to localize the electrodes' stimulated contacts. To assess our method, we applied our algorithm on 25 patients who had undergone bilateral STNDBS. We found a placement error of 0.91+/-0.38 mm. Then, from the segmented axis, we quantitatively analyzed the electrodes' curvature and correlated it with patients' clinical data. We found a positive significant correlation between mean curvature index of the electrode and brain atrophy index for male patients and between mean curvature index of the electrode and mean PD duration for female patients. These results help understanding DBS electrode' deformations and would help ensuring better anticipation of electrodes' placement.

Human factors engineering and design validation for the redesigned follitropin alfa pen injection device.

PubMed

Mahony, Mary C; Patterson, Patricia; Hayward, Brooke; North, Robert; Green, Dawne

2015-05-01

To demonstrate, using human factors engineering (HFE), that a redesigned, pre-filled, ready-to-use, pre-asembled follitropin alfa pen can be used to administer prescribed follitropin alfa doses safely and accurately. A failure modes and effects analysis identified hazards and harms potentially caused by use errors; risk-control measures were implemented to ensure acceptable device use risk management. Participants were women with infertility, their significant others, and fertility nurse (FN) professionals. Preliminary testing included 'Instructions for Use' (IFU) and pre-validation studies. Validation studies used simulated injections in a representative use environment; participants received prior training on pen use. User performance in preliminary testing led to IFU revisions and a change to outer needle cap design to mitigate needle stick potential. In the first validation study (49 users, 343 simulated injections), in the FN group, one observed critical use error resulted in a device design modification and another in an IFU change. A second validation study tested the mitigation strategies; previously reported use errors were not repeated. Through an iterative process involving a series of studies, modifications were made to the pen design and IFU. Simulated-use testing demonstrated that the redesigned pen can be used to administer follitropin alfa effectively and safely.

SU-F-T-09: In Phantom Full-Implant Validation of Plastic Scintillation Detectors for in Vivo Dosimetry During Low Dose Rate Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Therriault-Proulx, F; Bruno, T; Beddar, S

Purpose: To validate in a water phantom the use of plastic scintillation detectors to measure dose to the urethra and the rectal wall during a clinically realistic low dose rate (LDR) brachytherapy implant. Methods: A template was designed to replicate a clinically realistic LDR brachytherapy prostate implant inside a water phantom. Twenty-two catheters were inserted, including one mimicking the urethra and another the rectal wall. The needles inserted in the remaining 20 catheters were composed of thin-walled nylon tubes in which I-125 radioactive seeds (Air Kerma Strengths of (0.328±0.020)U) were abutted together with plastic spacers to replicate a typical loading.more » A plastic scintillation detector (PSD) with a 5-mm long × 1-mm diameter sensitive element was first placed inside the urethra and 1-second measurements were performed for 60s after each needle implant. Measurements were also performed at multiple positions along the urethra once all the needles were inserted. The procedure was then repeated with the PSD placed at the rectal wall. Results: Individual dose-rates ranging from 0.07µGy/s to 1.5µGy/s were measured after each needle implant. The average absolute relative differences were (6.2±3.6)% and (6.9±6.5)% to the values calculated with the TG-43 formalism, for the urethra and rectal wall respectively. These results are within expectations from the error uncertainty budget once accounting for uncertainties in seeds’ strength and positioning. Interestingly, the PSD allowed for unplanned error detection as the study was performed. Finally, the measured dose after the full implant at different positions along the mimicked organs at risk were in agreement with TG-43 values for all of the positions tested. Conclusion: Plastic scintillation detectors could be used as in vivo detectors for LDR brachytherapy as they would provide accurate dose information after each needle implant as well as along the organs at risk at the end of the implant.« less

Sci-Thur AM: YIS – 03: Combining sagittally-reconstructed 3D and live-2D ultrasound for high-dose-rate prostate brachytherapy needle segmentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hrinivich, Thomas; Hoover, Douglas; Surry, Kathlee

Ultrasound-guided high-dose-rate prostate brachytherapy (HDR-BT) needle segmentation is performed clinically using live-2D sagittal images. Organ segmentation is then performed using axial images, introducing a source of geometric uncertainty. Sagittally-reconstructed 3D (SR3D) ultrasound enables both needle and organ segmentation, but suffers from shadow artifacts. We present a needle segmentation technique augmenting SR3D with live-2D sagittal images using mechanical probe tracking to mitigate image artifacts and compare it to the clinical standard. Seven prostate cancer patients underwent TRUS-guided HDR-BT during which the clinical and proposed segmentation techniques were completed in parallel using dual ultrasound video outputs. Calibrated needle end-length measurements were usedmore » to calculate insertion depth errors (IDEs), and the dosimetric impact of IDEs was evaluated by perturbing clinical treatment plan source positions. The proposed technique provided smaller IDEs than the clinical approach, with mean±SD of −0.3±2.2 mm and −0.5±3.7mm respectively. The proposed and clinical techniques resulted in 84% and 43% of needles with IDEs within ±3mm, and IDE ranges across all needles of [−7.7mm, 5.9mm] and [−9.3mm, 7.7mm] respectively. The proposed and clinical IDEs lead to mean±SD changes in the volume of the prostate receiving the prescription dose of −0.6±0.9% and −2.0±5.3% respectively. The proposed technique provides improved HDR-BT needle segmentation accuracy over the clinical technique leading to decreased dosimetric uncertainty by eliminating the axial-to-sagittal registration, and mitigates the effect of shadow artifacts by incorporating mechanically registered live-2D sagittal images.« less

The effect of second-stage pushing and body mass index on postdural puncture headache.

PubMed

Franz, Amber M; Jia, Shawn Y; Bahnson, Henry T; Goel, Akash; Habib, Ashraf S

2017-02-01

To explore how pushing during labor and body mass index affect the development of postdural puncture headache in parturients who experienced dural puncture with Tuohy needles. Retrospective cohort. Obstetric ward and operating rooms at a university-affiliated hospital. One hundred ninety parturients who had witnessed dural puncture with 17 or 18 gauge Tuohy needles from 1999-2014. Patients were categorized by pushing status and body mass index (kg/m 2 ): nonobese <30, obese 30-39.99, morbidly obese 40-49.99, and super obese ≥50. Headache, number of days of headache, maximum headache score, and epidural blood patch placement. Compared with women who did not push, women who pushed during labor had increased risk of postdural puncture headache (odds ratio [OR], 2.1 [1.1-4.0]; P=.02), more days of headache (P=.02), and increased epidural blood patch placement (P=.02). Super obese patients were less likely to develop headache compared with nonobese (OR, 0.33 [0.13-0.85]; P=.02), obese (OR, 0.37 [0.14-0.98]; P=.045], and morbidly obese patients (OR, 0.20 [0.05-0.68]; P<.01). In a multivariate logistic regression model, lack of pushing (OR, 0.57 [0.29-1.10]; P=.096) and super obesity (OR, 0.41 [0.16-1.02]; P=.056] were no longer significantly associated with reduced risk of postdural puncture headache. Parturients who did not push before delivery and parturients with body mass index ≥50kg/m 2 were less likely to develop postdural puncture headache in a univariate analysis. Similar trends were demonstrated in a multivariate model, but were no longer statistically significant. Copyright © 2016 Elsevier Inc. All rights reserved.

Image-guided placement of port catheters: is there an increased risk of infection if the port is immediately accessed and used?

PubMed

Salazar, Gloria; Yeddula, Kalpana; Wicky, Stephan; Oklu, Ramhi; Ganguli, Suvranu; Waltman, Arthur C; Walker, Thomas G; Kalva, Sanjeeva P

2013-01-01

To compare complication rates in patients who have port-a-catheters inserted and left accessed for immediate use and those who have ports inserted but not accessed. In this retrospective, IRB-approved study, medical records of patients who received a port catheter between 9/2009 and 2/2010 were reviewed. The data collected included patient demographics, diagnosis, procedure and complications. The patients were categorized into two groups: accessed (patients in whom the port was accessed with a Huber needle for immediate intravenous use and the patient left the procedure area with needle indwelling) and control (patients in whom the ports were not accessed). Complications were classified according to Society of Interventional Radiology guidelines. Results are given as mean ±SD. Statistical analysis was performed with student t test and statistical significance was considered at P<.05. A total of 467 ports were placed in 465 patients (Men: 206); 10.7% in the accessed group (n=50, age: 60±13.9) and 89.3% in the control group (n=417, age: 59±13.5). There were no statistically significant differences in patient demographics between the groups. The overall complication rate was 0.6% (n=3). Two complications (hematoma causing skin necrosis and thrombosis of the port) occurred in the control group and one (infection) in the accessed group. Infection rates after procedures were 2% (1/50) in the accessed group and 0% (0/417) in the control group. There was no statistically significant difference in overall complication (P=.1) and infection (P=.1) rates among the groups. Leaving the port accessed immediately after placement does not increase the risk of infection or other complications.

Fast MRI-guided vacuum-assisted breast biopsy: initial experience.

PubMed

Liberman, Laura; Morris, Elizabeth A; Dershaw, D David; Thornton, Cynthia M; Van Zee, Kimberly J; Tan, Lee K

2003-11-01

The purpose of this study was to evaluate a new method for performing MRI-guided vacuum-assisted breast biopsy in a study of lesions that had subsequent surgical excision. SUBJECTS AND METHODS. Twenty women scheduled for MRI-guided needle localization and surgical biopsy were prospectively entered in the study. MRI-guided biopsy was performed with a vacuum-assisted probe, followed by placement of a localizing clip, and then needle localization for surgical excision. Vacuum-assisted biopsy and surgical histology were correlated. Vacuum-assisted biopsy was successfully performed in 19 (95%) of the 20 women. The median size of 27 MRI-detected lesions that had biopsy was 1.0 cm (range, 0.4-6.4 cm). Cancer was present in eight (30%) of 27 lesions and in six (32%) of 19 women; among these eight cancers, five were infiltrating and three were ductal carcinoma in situ (DCIS). Among these 27 lesions, histology was benign at vacuum-assisted biopsy and at surgery in 19 (70%), cancer at vacuum-assisted biopsy in six (22%), atypical ductal hyperplasia at vacuum-assisted biopsy and DCIS at surgery in one (4%), and benign at vacuum-assisted biopsy with surgery showing microscopic DCIS that was occult at MRI in one (4%). The median time to perform vacuum-assisted biopsy of a single lesion was 35 min (mean, 35 min; range, 24-48 min). Placement of a localizing clip, attempted in 26 lesions, was successful in 25 (96%) of 26, and the clip was retrieved on specimen radiography in 22 (96%) of 23. One complication occurred: a hematoma that resolved with compression. MRI-guided vacuum-assisted biopsy is a fast, safe, and accurate alternative to surgical biopsy for breast lesions detected on MRI.

The effectiveness of cut-proof glove liners: cut and puncture resistance, dexterity, and sensibility.

PubMed

Salkin, J A; Stuchin, S A; Kummer, F J; Reininger, R

1995-11-01

Five types of commercial glove liners (within double latex gloves) were compared to single and double latex gloves for cut and puncture resistance and for relative manual dexterity and degree of sensibility. An apparatus was constructed to test glove-pseudofinger constructs in either a cutting or puncture mode. Cutting forces, cutting speed, and type of blade (serrated or scalpel blade) were varied and the time to cut-through measured by an electrical conductivity circuit. Penetration forces were similarly determined with a scalpel blade and a suture needle using a spring scale loading apparatus. Dexterity was measured with an object placement task among a group of orthopedic surgeons. Sensibility was assessed with Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry using standard techniques and rating scales. A subjective evaluation was performed at the end of testing. Time to cut-through for the liners ranged from 2 to 30 seconds for a rapid oscillating scalpel and 4 to 40 seconds for a rapid oscillating serrated knife under minimal loads. When a 1 kg load was added, times to cut-through ranged from 0.4 to 1.0 second. In most cases, the liners were superior to double latex. On average, 100% more force was required to penetrate the liners with a scalpel and 50% more force was required to penetrate the liners with a suture needle compared to double latex. Object placement task times were not significantly liners compared to double latex gloves. Semmes-Weinstein monofilaments, two-point discrimination, and vibrametry showed no difference in sensibility among the various liners and double latex gloves. Subjects felt that the liners were minimally to moderately impairing. An acclimation period may be required for their effective use.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirata, Masaaki, E-mail: masaaki314@gmail.com; Watanabe, Ryouhei; Koyano, Yasuhiro

PurposeTo demonstrate the use of “Smart Puncture,” a smartphone application to assist conventional CT-guided puncture without CT fluoroscopy, and to describe the advantages of this application.Materials and MethodsA puncture guideline is displayed by entering the angle into the application. Regardless of the angle at which the device is being held, the motion sensor ensures that the guideline is displayed at the appropriate angle with respect to gravity. The angle of the smartphone’s liquid crystal display (LCD) is also detected, preventing needle deflection from the CT slice image. Physicians can perform the puncture procedure by advancing the needle using the guidelinemore » while the smartphone is placed adjacent to the patient. In an experimental puncture test using a sponge as a target, the target was punctured at 30°, 50°, and 70° when the device was tilted to 0°, 15°, 30°, and 45°, respectively. The punctured target was then imaged with a CT scan, and the puncture error was measured.ResultsThe mean puncture error in the plane parallel to the LCD was less than 2°, irrespective of device tilt. The mean puncture error in the sagittal plane was less than 3° with no device tilt. However, the mean puncture error tended to increase when the tilt was increased.ConclusionThis application can transform a smartphone into a valuable tool that is capable of objectively and accurately assisting CT-guided puncture procedures.« less

Time-resolved in vivo luminescence dosimetry for online error detection in pulsed dose-rate brachytherapy.

PubMed

Andersen, Claus E; Nielsen, Søren Kynde; Lindegaard, Jacob Christian; Tanderup, Kari

2009-11-01

The purpose of this study is to present and evaluate a dose-verification protocol for pulsed dose-rate (PDR) brachytherapy based on in vivo time-resolved (1 s time resolution) fiber-coupled luminescence dosimetry. Five cervix cancer patients undergoing PDR brachytherapy (Varian GammaMed Plus with 192Ir) were monitored. The treatments comprised from 10 to 50 pulses (1 pulse/h) delivered by intracavitary/interstitial applicators (tandem-ring systems and/or needles). For each patient, one or two dosimetry probes were placed directly in or close to the tumor region using stainless steel or titanium needles. Each dosimeter probe consisted of a small aluminum oxide crystal attached to an optical fiber cable (1 mm outer diameter) that could guide radioluminescence (RL) and optically stimulated luminescence (OSL) from the crystal to special readout instrumentation. Positioning uncertainty and hypothetical dose-delivery errors (interchanged guide tubes or applicator movements from +/-5 to +/-15 mm) were simulated in software in order to assess the ability of the system to detect errors. For three of the patients, the authors found no significant differences (P>0.01) for comparisons between in vivo measurements and calculated reference values at the level of dose per dwell position, dose per applicator, or total dose per pulse. The standard deviations of the dose per pulse were less than 3%, indicating a stable dose delivery and a highly stable geometry of applicators and dosimeter probes during the treatments. For the two other patients, the authors noted significant deviations for three individual pulses and for one dosimeter probe. These deviations could have been due to applicator movement during the treatment and one incorrectly positioned dosimeter probe, respectively. Computer simulations showed that the likelihood of detecting a pair of interchanged guide tubes increased by a factor of 10 or more for the considered patients when going from integrating to time-resolved dose verification. The likelihood of detecting a +/-15 mm displacement error increased by a factor of 1.5 or more. In vivo fiber-coupled RL/OSL dosimetry based on detectors placed in standard brachytherapy needles was demonstrated. The time-resolved dose-rate measurements were found to provide a good way to visualize the progression and stability of PDR brachytherapy dose delivery, and time-resolved dose-rate measurements provided an increased sensitivity for detection of dose-delivery errors compared with time-integrated dosimetry.

Use of a lumen-apposing metal stent to treat GI strictures (with videos).

PubMed

Irani, Shayan; Jalaj, Sujai; Ross, Andrew; Larsen, Michael; Grimm, Ian S; Baron, Todd H

2017-06-01

Benign GI strictures occur typically in the esophagus and pyloric channel but can occur anywhere in the GI tract and at anastomotic sites. Such strictures can be treated with dilation, incisional therapy, steroid injection, and stents. Our aim was to describe the use of a lumen-apposing metal stent (LAMS) to treat short, benign GI strictures. Consecutive patients who underwent LAMS placement for various benign strictures at 2 tertiary care centers from August 2014 to November 2015 were reviewed retrospectively. The main outcome measures were technical success, clinical success, stent migration, and adverse events. Twenty-five patients (7 males, 18 females) with a median age of 54 years (33-85 years) underwent 28 LAMS placements to treat various benign strictures. The location of the strictures included esophagogastric anastomoses (n=4), gastrojejunal anastomoses (n=13), pylorus (n=6), vertical banded gastroplasty (n=1), and ileocolonic anastomosis (n=1). Twenty patients had been previously treated with dilation alone (9 patients with ≥3 dilations), 11 patients with dilation and steroid injection, 2 patients with additional needle-knife therapy, and 1 patient with placement of a traditional fully covered self-expandable metal stent. A 15-mm internal diameter LAMS was placed in all patients; 3 patients had been treated previously with a 10-mm LAMS. Technical success was achieved in all patients, whereas clinical success was achieved in 15 of 25 patients (60%) who completed a minimum of 6 months of follow-up after placement. Median stent dwell time was 92 days (range, 3-273 days). Stent migration was seen in 2 of 28 stent placements (7%). Four of 25 patients (16%) developed 5 moderate adverse events (pain requiring removal, 2; new stricture formation, 2; bleeding, 1). Median follow-up was 301 days after stent placement. Study limitations include the small, select group of patients, the retrospective study design, and short follow-up. LAMS placement for benign GI strictures is technically easy and safe with low migration rates and may be an option to treat selected patients with short-length strictures. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Preoperative Direct Puncture Embolization of Advanced Juvenile Nasopharyngeal Angiofibroma in Combination with Transarterial Embolization: An Analysis of 22 Consecutive Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv Mingming, E-mail: lvmingming001@163.com; Fan, Xin-dong, E-mail: fanxindong@yahoo.com.cn; Su Lixin, E-mail: sulixin1975@126.com

2013-02-15

ObjectiveThis study was designed to evaluate the clinical application of preoperative auxiliary embolization for juvenile nasopharyngeal angiofibroma (JNA) by direct puncture embolization (DPE) of the tumor in combination with transarterial embolization (TAE). The study included 22 patients. An 18-gauge needle was used to puncture directly into the tumor, and 20-25 % N-butyl cyanoacrylate was injected under the guidance of fluoroscopy after confirming the placement of the needle into the JNA and no leaking into the surrounding tissue. Tumors were obstructed later via TAE. The supplying arteries of JNA were from branches of the internal carotid and external carotid arteries. Controlmore » angiography showed the obliteration of contrast stain in the entire tumor mass and the distal supplying arteries disappeared after DPE in combination with TAE. Surgical resection was performed within 4 days after embolization and none of the patients required blood transfusion. The use of DPE in combination with TAE was a safe, feasible, and efficacious method. It can devascularize effectively the JNAs and reduce intraoperative bleeding when JNAs are extirpated.« less

A Single-Institution Experience in Percutaneous Image-Guided Biopsy of Malignant Pleural Mesothelioma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welch, B. T., E-mail: Welch.brian@mayo.edu; Eiken, P. W.; Atwell, T. D.

PurposeMesothelioma has been considered a difficult pathologic diagnosis to achieve via image-guided core needle biopsy. The purpose of this study was to assess the diagnostic sensitivity of percutaneous image-guided biopsy for diagnosis of pleural mesothelioma.Materials and MethodsRetrospective review was performed to identify patients with a confirmed diagnosis of pleural mesothelioma and who underwent image-guided needle biopsy between January 1, 2002, and January 1, 2016. Thirty-two patients with pleural mesothelioma were identified and included for analysis in 33 image-guided biopsy procedures. Patient, procedural, and pathologic characteristics were recorded. Complications were characterized via standardized nomenclature [Common Terminology for Clinically Adverse Events (CTCAE)].ResultsPercutaneousmore » image-guided biopsy was associated with an overall sensitivity of 81%. No CTCAE clinically significant complications were observed. No image-guided procedures were complicated by pneumothorax or necessitated chest tube placement. No patients had tumor seeding of the biopsy tract.ConclusionPercutaneous image-guided biopsy can achieve high sensitivity for pathologic diagnosis of pleural mesothelioma with a low procedural complication rate, potentially obviating need for surgical biopsy.« less

Effect of surgical guide design and surgeon's experience on the accuracy of implant placement.

PubMed

Hinckfuss, Simon; Conrad, Heather J; Lin, Lianshan; Lunos, Scott; Seong, Wook-Jin

2012-08-01

Implant position is a key determinant of esthetic and functional success. Achieving the goal of ideal implant position may be affected by case selection, prosthodontically driven treatment planning, site preparation, surgeon's experience and use of a surgical guide. The combined effect of surgical guide design, surgeon's experience, and size of the edentulous area on the accuracy of implant placement was evaluated in a simulated clinical setting. Twenty-one volunteers were recruited to participate in the study. They were divided evenly into 3 groups (novice, intermediate, and experienced). Each surgeon placed implants in single and double sites using 4 different surgical guide designs (no guide, tube, channel, and guided) and written instructions describing the ideal implant positions. A definitive typodont was constructed that had 3 implants in prosthetically determined ideal positions of single and double sites. The position and angulation of implants placed by the surgeons in the duplicate typodonts was measured using a computerized coordinate measuring machine and compared to the definitive typodont. The mean absolute positional error for all guides was 0.273, 0.340, 0.197 mm in mesial-distal, buccal-lingual, vertical positions, respectively, with an overall range of 0.00 to 1.81 mm. The mean absolute angle error for all guides was 1.61° and 2.39° in the mesial-distal and buccal-lingual angulations, respectively, with an overall range of 0.01° to 9.7°. Surgical guide design had a statistically significant effect on the accuracy of implant placement regardless of the surgeon's experience level. Experienced surgeons had significantly less error in buccal-lingual angulation. The size of the edentulous sites was found to affect both implant angle and position significantly. The magnitude of error in position and angulation caused by surgical guide design, surgeon's experience, and site size reported in this study are possibly not large enough to be clinically significant; however, it is likely that errors would be magnified in clinical practice. Future research is recommended to evaluate the effect of surgical guide design in vivo on implant angulation and position error.

The Missed Inferior Alveolar Block: A New Look at an Old Problem

PubMed Central

Milles, Maano

1984-01-01

A variation of a previously described technique to obtain mandibular block anesthesia is presented. This technique varies from those previously described in that is uses palpable anatomic landmarks, both extra- and intraoral, to orient the placement of the needle. This technique relies on several readily observed landmarks and the integration of these landmarks. Because palpable landmarks are used, consistent results can be easily obtained even in patients who present with a wide variety of anatomical variances which otherwise make this injection technique difficult and prone to failure. ImagesFigure 1Figure 3Figure 4Figure 5Figure 6 PMID:6597690

The effectiveness of inking needle core prostate biopsies for preventing patient specimen identification errors: a technique to address Joint Commission patient safety goals in specialty laboratories.

PubMed

Raff, Lester J; Engel, George; Beck, Kenneth R; O'Brien, Andrea S; Bauer, Meagan E

2009-02-01

The elimination or reduction of medical errors has been a main focus of health care enterprises in the United States since the year 2000. Elimination of errors in patient and specimen identification is a key component of this focus and is the number one goal in the Joint Commission's 2008 National Patient Safety Goals Laboratory Services Program. To evaluate the effectiveness of using permanent inks to maintain specimen identity in sequentially submitted prostate needle biopsies. For a 12-month period, a grossing technician stained each prostate core with permanent ink developed for inking of pathology specimens. A different color was used for each patient, with all the prostate cores from all vials for a particular patient inked with the same color. Five colors were used sequentially: green, blue, yellow, orange, and black. The ink was diluted with distilled water to a consistency that allowed application of a thin, uniform coating of ink along the edges of the prostate core. The time required to ink patient specimens comprising different numbers of vials and prostate biopsies was timed. The number and type of inked specimen discrepancies were evaluated. The identified discrepancy rate for prostate biopsy patients was 0.13%. The discrepancy rate in terms of total number of prostate blocks was 0.014%. Diluted inks adhered to biopsy contours throughout tissue processing. The tissue showed no untoward reactions to the inks. Inking did not affect staining (histochemical or immunohistochemical) or pathologic evaluation. On average, inking prostate needle biopsies increases grossing time by 20%. Inking of all prostate core biopsies with colored inks, in sequential order, is an aid in maintaining specimen identity. It is a simple and effective method of addressing Joint Commission patient safety goals by maintaining specimen identity during processing of similar types of gross specimens. This technique may be applicable in other specialty laboratories and high-volume laboratories, where many similar tissue specimens are processed.

MRI-guided procedures in various regions of the body using a robotic assistance system in a closed-bore scanner: preliminary clinical experience and limitations.

PubMed

Moche, Michael; Zajonz, Dirk; Kahn, Thomas; Busse, Harald

2010-04-01

To present the clinical setup and workflow of a robotic assistance system for image-guided interventions in a conventional magnetic resonance imaging (MRI) environment and to report our preliminary clinical experience with percutaneous biopsies in various body regions. The MR-compatible, servo-pneumatically driven, robotic device (Innomotion) fits into the 60-cm bore of a standard MR scanner. The needle placement (n = 25) accuracy was estimated by measuring the 3D deviation between needle tip and prescribed target point in a phantom. Percutaneous biopsies in six patients and different body regions were planned by graphically selecting entry and target points on intraoperatively acquired roadmap MR data. For insertion depths between 29 and 95 mm, the average 3D needle deviation was 2.2 +/- 0.7 mm (range 0.9-3.8 mm). Patients with a body mass index of up to approximately 30 kg/m(2) fitted into the bore with the device. Clinical work steps and limitations are reported for the various applications. All biopsies were diagnostic and could be completed without any major complications. Median planning and intervention times were 25 (range 20-36) and 44 (36-68) minutes, respectively. Preliminary clinical results in a standard MRI environment suggest that the presented robotic device provides accurate guidance for percutaneous procedures in various body regions. Shorter procedure times may be achievable by optimizing technical and workflow aspects. (c) 2010 Wiley-Liss, Inc.

Monte Carlo simulation of edge placement error

NASA Astrophysics Data System (ADS)

Kobayashi, Shinji; Okada, Soichiro; Shimura, Satoru; Nafus, Kathleen; Fonseca, Carlos; Estrella, Joel; Enomoto, Masashi

2018-03-01

In the discussion of edge placement error (EPE), we proposed interactive pattern fidelity error (IPFE) as an indicator to judge pass/fail of integrated patterns. IPFE consists of lower and upper layer EPEs (CD and center of gravity: COG) and overlay, which is decided from the combination of each maximum variation. We succeeded in obtaining the IPFE density function by Monte Carlo simulation. In the results, we also found that the standard deviation (σ) of each indicator should be controlled by 4.0σ, at the semiconductor grade, such as 100 billion patterns per die. Moreover, CD, COG and overlay were analyzed by analysis of variance (ANOVA); we can discuss all variations from wafer to wafer (WTW), pattern to pattern (PTP), line edge roughness (LWR) and stochastic pattern noise (SPN) on an equal footing. From the analysis results, we can determine that these variations belong to which process and tools. Furthermore, measurement length of LWR is also discussed in ANOVA. We propose that the measurement length for IPFE analysis should not be decided to the micro meter order, such as >2 μm length, but for which device is actually desired.

Toward dynamic lumbar punctures guidance based on single element synthetic tracked aperture ultrasound imaging

NASA Astrophysics Data System (ADS)

Zhang, Haichong K.; Lin, Melissa; Kim, Younsu; Paredes, Mateo; Kannan, Karun; Patel, Nisu; Moghekar, Abhay; Durr, Nicholas J.; Boctor, Emad M.

2017-03-01

Lumbar punctures (LPs) are interventional procedures used to collect cerebrospinal fluid (CSF), a bodily fluid needed to diagnose central nervous system disorders. Most lumbar punctures are performed blindly without imaging guidance. Because the target window is small, physicians can only accurately palpate the appropriate space about 30% of the time and perform a successful procedure after an average of three attempts. Although various forms of imaging based guidance systems have been developed to aid in this procedure, these systems complicate the procedure by including independent image modalities and requiring image-to-needle registration to guide the needle insertion. Here, we propose a simple and direct needle insertion platform utilizing a single ultrasound element within the needle through dynamic sensing and imaging. The needle-shaped ultrasound transducer can not only sense the distance between the tip and a potential obstacle such as bone, but also visually locate structures by combining transducer location tracking and back projection based tracked synthetic aperture beam-forming algorithm. The concept of the system was validated through simulation first, which revealed the tolerance to realistic error. Then, the initial prototype of the single element transducer was built into a 14G needle, and was mounted on a holster equipped with a rotation tracking encoder. We experimentally evaluated the system using a metal wire phantom mimicking high reflection bone structures and an actual spine bone phantom with both the controlled motion and freehand scanning. An ultrasound image corresponding to the model phantom structure was reconstructed using the beam-forming algorithm, and the resolution was improved compared to without beam-forming. These results demonstrated the proposed system has the potential to be used as an ultrasound imaging system for lumbar puncture procedures.

Fluoroscopy-Guided Sacroiliac Joint Injection: Description of a Modified Technique.

PubMed

Kasliwal, Prasad Jaychand; Kasliwal, Sapana

2016-02-01

Sacroiliac joint (SIJ) pathology is a common etiologic cause for 10 - 27% of cases of mechanical low back pain (LBP) below the L5 level. In the absence of definite clinical or radiologic diagnostic criteria, controlled blocks of the SIJ have become the choice assessment method for making the diagnosis of SIJ pain. The SI joint is most often characterized as a large, auricular-shaped, diarthrodial synovial joint. In reality, its synovial characteristic is limited only to the distal third and anterior third. In SIJ interventions, the lateral view has been underutilized. In our technique, we used the lateral view to create a three-dimensional view of the SIJ to aid in gauging the accurateness of the contrast spread and to obtain a precise block. After obtaining appropriate fluoroscopic images, a curved tip spinal needle was directed into the inferior aspect of the SIJ using a posterior approach. As the needle contacts firm tissues on the posterior aspect of the joint, position of the needle tip is checked using lateral fluoroscopy. In the lateral view, the needle tip position is manipulated to keep it in the anterior third of the SIJ and contrast is injected. Our criteria for accurate SIJ block, in posteroanterior (PA) view, is the injection of the contrast medium should outline the joint space and the contrast medium should be seen to travel cephalad along the joint line. In the lateral view, the contrast medium most densely outlines the parameter of the joint. We have utilized this method with good effect in approximately 30 cases over one year. Out of 30 cases, needle position and contrast spread was satisfactory in 28 and 27 cases, respectively. So satisfactory needle placement and contrast spread was in 93% and 87% cases. Pain relief of 80% or more after intra-articular injection of local anesthetic was seen in 50% (15 of 30) patients; pain relief of 50 - 79% was witnessed in 30% (9 of 30) patients. Thus, pain decreased 50% or more in 80% (24 of 30) of the joints. Out of 24 joints where we got satisfactory needle position and contrast spread, 23 joints got more than 50% relief. Thus, if needle position and contrast spread is satisfactory as per the criteria, pain relief of 50% or more was in 96% (23 of 24) of joints. There are few possible limitations with this study like difficulty to go up to the anterior third of the SIJ, it may be more painful as a narrow joint line has to be travelled in depth, sciatic numbness due to drug leak, or injuring the pelvic structure. Advantages of this method are that depth and level of the needle tip for a SIJ block is described for the more precise block. This will reduce false positive and false negative results, i.e., sensitivity and specificity of SIJ blocks and results for diagnostic blocks become more reliable. It will also reduce the chances of a case getting abandoned due to inappropriate contrast spread obscuring the fluoroscopic landmarks. As we know the depth of the needle, the chances of injuring pelvic structures become less and safety improves.

[A comparative study between two procedures of TVT retropubic mid-urethral sling placement for treatment of female stress urinary incontinence].

PubMed

Sergent, F; Gay-Crosier, G; Resch, B; Pons, J-C; Marpeau, L

2014-03-01

To evaluate complications and functional outcomes at 1 year and more of a modified Tension-free Vaginal Tape (TVT) technique from that of classic TVT. Retrospective study comparing the two techniques. For the modified TVT technique, a peri-urethrovesical hydrodissection was performed. An 18-gauge hollow needle, in which a thread was introduced, was used as an ancillary for the placement of the sling. The sling was secured to the thread and then positioned with it. Bladder filling objectified perforations. An absorbable suture around the sling allowed its descent if necessary. One hundred and eighteen procedures were performed (54 classic TVT and 64 modified TVT). For the standard TVT and the modified TVT, the vesico-urethral perforation rates were respectively 7.4% and 1.5% (P<0.05), those of reoperations for pulling the sling downward 11.1% and 1.5% (P<0.05). A 1 year and more, healing and satisfaction rates were respectively 83.3% and 79.2% for the standard TVT versus 88.2% and 90% for the modified TVT (NS). The dissatisfaction rate was lower for the modified TVT (P<0.05). By modifying the placement of the classic TVT, it is possible to reduce its complications while maintaining its efficacy. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Optimal Multi-Type Sensor Placement for Structural Identification by Static-Load Testing

PubMed Central

Papadopoulou, Maria; Vernay, Didier; Smith, Ian F. C.

2017-01-01

Assessing ageing infrastructure is a critical challenge for civil engineers due to the difficulty in the estimation and integration of uncertainties in structural models. Field measurements are increasingly used to improve knowledge of the real behavior of a structure; this activity is called structural identification. Error-domain model falsification (EDMF) is an easy-to-use model-based structural-identification methodology which robustly accommodates systematic uncertainties originating from sources such as boundary conditions, numerical modelling and model fidelity, as well as aleatory uncertainties from sources such as measurement error and material parameter-value estimations. In most practical applications of structural identification, sensors are placed using engineering judgment and experience. However, since sensor placement is fundamental to the success of structural identification, a more rational and systematic method is justified. This study presents a measurement system design methodology to identify the best sensor locations and sensor types using information from static-load tests. More specifically, three static-load tests were studied for the sensor system design using three types of sensors for a performance evaluation of a full-scale bridge in Singapore. Several sensor placement strategies are compared using joint entropy as an information-gain metric. A modified version of the hierarchical algorithm for sensor placement is proposed to take into account mutual information between load tests. It is shown that a carefully-configured measurement strategy that includes multiple sensor types and several load tests maximizes information gain. PMID:29240684

Safety of Acupuncture Practice in Japan: Patient Reactions, Therapist Negligence and Error Reduction Strategies

PubMed Central

Tsukayama, Hiroshi

2008-01-01

Evidence-based approach on the safety of acupuncture had been lagging behind both in the West and the East, but reliable data based on some prospective surveys were published after the late 1990s. In the present article, we, focusing on ‘Japanese acupuncture’, review relevant case reports and prospective surveys on adverse events in Japan, assess the safety of acupuncture practice in this country, and suggest a strategy for reducing the therapists’ error. Based on the prospective surveys, it seems reasonable to suppose that serious adverse events are rare in standard practice by adequately trained acupuncturists, regardless of countries or modes of practice. Almost all of adverse reactions commonly seen in acupuncture practice—such as fatigue, drowsiness, aggravation, minor bleeding, pain on insertion and subcutaneous hemorrhage—are mild and transient, although we should be cautious of secondary injury following drowsiness and needle fainting. After demonstrating that acupuncture is inherently safe, we have been focusing on how to reduce the risk of negligence in Japan, as well as educating acupuncturists more about safe depth of insertion and infection control. Incident reporting and feedback system is a useful strategy for reducing therapist errors such as forgotten needles. For the benefit of acupuncture patients in Japan, it is important to establish mandatory postgraduate clinical training and continued education system. PMID:18955234

Smart surgical needle actuated by shape memory alloys for percutaneous procedures

NASA Astrophysics Data System (ADS)

Konh, Bardia

Background: Majority of cancer interventions today are performed percutaneously using needle-based procedures, i.e. through the skin and soft tissue. Insufficient accuracy using conventional surgical needles motivated researchers to provide actuation forces to the needle's body for compensating the possible errors of surgeons/physicians. Therefore, active needles were proposed recently where actuation forces provided by shape memory alloys (SMAs) are utilized to assist the maneuverability and accuracy of surgical needles. This work also aims to introduce a novel needle insertion simulation to predict the deflection of a bevel tip needle inside the tissue. Methods: In this work first, the actuation capability of a single SMA wire was studied. The complex response of SMAs was investigated via a MATLAB implementation of the Brinson model and verified via experimental tests. The material characteristics of SMAs were simulated by defining multilinear elastic isothermal stress-strain curves. Rigorous experiments with SMA wires were performed to determine the material properties as well as to show the capability of the code to predict a stabilized SMA transformation behavior with sufficient accuracy. The isothermal stress-strain curves of SMAs were simulated and defined as a material model for the Finite Element Analysis of the active needle. In the second part of this work, a three-dimensional finite element (FE) model of the active steerable needle was developed to demonstrate the feasibility of using SMA wires as actuators to bend the surgical needle. In the FE model, birth and death method of defining boundary conditions, available in ANSYS, was used to achieve the pre-strain condition on SMA wire prior to actuation. This numerical model was validated with needle deflection experiments with developed prototypes of the active needle. The third part of this work describes the design optimization of the active using genetic algorithm aiming for its maximum flexibility. Design parameters influencing the steerability include the needle's diameter, wire diameter, pre-strain, and its offset from the needle. A simplified model was developed to decrease the computation time in iterative analyses of the optimization algorithm. In the fourth part of this work a design of an active needling system was proposed where actuation forces of SMAs as well as shape memory polymers (SMPs) were incorporated. SMP elements provide two major additional advantages to the design: (i) recovery of the SMP's plastic deformation by heating the element above its glass transition temperature, and (ii) achieving a higher needle deflection by having a softer stage of SMP at higher temperatures with less amount of actuation force. Finally, in the fifth and last part of this study, an Arbitrary-Lagrangian-Eulerian formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. A 150mm long needle was considered to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Some additional assumptions were made to maintain a reasonable computational time, with no need of parallel processing, while having practical accuracies. Three experimental tests of needle steering in a soft phantom were performed to validate the simulation. Results: The finite element model of the active needle was first validated experimentally with developed prototypes. Several design parameters affecting the needle's deflection such as the needle's Young's modulus, the SMA's pre-strain and its offset from the neutral axis of the cannula were studied using the FE model. Then by the integration of the SMA characteristics with the automated optimization schemes an improved design of the active needle was obtained. Real-time experiments with different prototypes showed that the quickest response and the maximum deflection were achieved by the needle with two sections of actuation compared to a single section of actuation. Also the feasibility of providing actuation forces using both SMAs and SMPs for the surgical needle was demonstrated in this study. The needle insertion simulation was validated while observing less than 10% deviation between the estimated amount of needle deflection by the simulation and by the experiments. Using this model the effect of needle diameter and its bevel tip angle on the final shape of the needle was investigated. Conclusion: The numerical and experimental studies of this work showed that a highly maneuverable active needle can be made using the actuation of multiple SMA wires in series. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies. (Abstract shortened by UMI.).

Flat epithelial atypia of the breast on core needle biopsy: an indication for surgical excision.

PubMed

Sohn, Vance; Porta, Rees; Brown, Tommy

2011-11-01

Flat epithelial atypia (FEA) is an increasingly diagnosed breast lesion yet there remains a paucity of data regarding these findings and their clinical significance. By determining the pathologic concordance rate, we sought to evaluate the indications for surgical intervention for FEAs diagnosed on core needle biopsy (CNB). Using a retrospective review of an international pathology referral center database, we included all breast CNB specimens with FEA as the most advanced diagnosis that underwent surgical excision. Patient demographics, caliber of biopsy needle, and pathology results were then analyzed. Between 2000 and 2009, 463 FEAs were diagnosed among 15,000 specimens referred for expert opinion. Twenty-four lesions (5%) met inclusion criteria. Sampling ranged from 8- to 18-guage needles. Two lesions (8.4%) were upgraded after surgical excision; one patient was found to have infiltrating ductal carcinoma and another with tubular carcinoma. Twelve patients who were diagnosed with FEA did not undergo surgical excision but had no immediate evidence of malignancy. Based on the 8.4% upgrade rate, FEA diagnosed on CNB requires follow-up surgical excision. Regardless of CNB caliber, the risk of sampling error precludes nonoperative management and FEA should be considered an at-risk lesion until more studies and pooled analysis prove otherwise.

Regionalization of Habitat Suitability of Masson’s Pine based on geographic information system and Fuzzy Matter-Element Model

PubMed Central

Zhou, Xiuteng; Zhao, Manxi; Zhou, Liangyun; Yang, Guang; Huang, Luqi; Yan, Cuiqi; Huang, Quanshu; Ye, Liang; Zhang, Xiaobo; Guo, Lanpin; Ke, Xiao; Guo, Jiao

2016-01-01

Pine needles have been widely used in the development of anti-hypertensive and anti-hyperlipidemic agents and health food. However, the widespread distribution of this tree poses great obstacles to the quality control and efficacy evaluation. To facilitate the effective and rational exploitation of Masson’s pine (Pinus massoniana Lamb), as well as ensure effective development of Masson’s pine needles as a medicinal agent, we investigated the spatial distribution of habitat suitability and evaluated the optimal ranges of ecological factors of P. massoniana with 280 samples collected from 12 provinces in China through the evaluation of four constituents known to be effective medicinally. The results of habitat suitability evaluation were also verified by Root Mean Square Error (RMSE). Finally, five ecological factors were chosen in the establishment of a habitat suitability evaluation system. The most suitable areas for P. massoniana growth were mainly concentrated in the middle and lower reaches of the Yangtze River basin, such as Sichuan, Guizhou, and Jiangxi provinces, while the best quality needles were from Guizhou, Sichuan, and the junction area of Chongqing, Hunan, and Hubei provinces. This information revealed that suitable areas for effective constituent accumulation of Masson’s pine needles accounted for only 7.41% of its distribution area. PMID:27694967

Regionalization of Habitat Suitability of Masson’s Pine based on geographic information system and Fuzzy Matter-Element Model

NASA Astrophysics Data System (ADS)

Zhou, Xiuteng; Zhao, Manxi; Zhou, Liangyun; Yang, Guang; Huang, Luqi; Yan, Cuiqi; Huang, Quanshu; Ye, Liang; Zhang, Xiaobo; Guo, Lanpin; Ke, Xiao; Guo, Jiao

2016-10-01

Pine needles have been widely used in the development of anti-hypertensive and anti-hyperlipidemic agents and health food. However, the widespread distribution of this tree poses great obstacles to the quality control and efficacy evaluation. To facilitate the effective and rational exploitation of Masson’s pine (Pinus massoniana Lamb), as well as ensure effective development of Masson’s pine needles as a medicinal agent, we investigated the spatial distribution of habitat suitability and evaluated the optimal ranges of ecological factors of P. massoniana with 280 samples collected from 12 provinces in China through the evaluation of four constituents known to be effective medicinally. The results of habitat suitability evaluation were also verified by Root Mean Square Error (RMSE). Finally, five ecological factors were chosen in the establishment of a habitat suitability evaluation system. The most suitable areas for P. massoniana growth were mainly concentrated in the middle and lower reaches of the Yangtze River basin, such as Sichuan, Guizhou, and Jiangxi provinces, while the best quality needles were from Guizhou, Sichuan, and the junction area of Chongqing, Hunan, and Hubei provinces. This information revealed that suitable areas for effective constituent accumulation of Masson’s pine needles accounted for only 7.41% of its distribution area.

Hesitation and error: Does product placement in an emergency department influence hand hygiene performance?

PubMed

Stackelroth, Jenny; Sinnott, Michael; Shaban, Ramon Z

2015-09-01

Existing research has consistently demonstrated poor compliance by health care workers with hand hygiene standards. This study examined the extent to which incorrect hand hygiene occurred as a result of the inability to easily distinguish between different hand hygiene solutions placed at washbasins. A direct observational method was used using ceiling-mounted, motion-activated video camera surveillance in a tertiary referral emergency department in Australia. Data from a 24-hour period on day 10 of the recordings were collected into the Hand Hygiene-Technique Observation Tool based on Feldman's criteria as modified by Larson and Lusk. A total of 459 episodes of hand hygiene were recorded by 6 video cameras in the 24-hour period. The observed overall rate of error in this study was 6.2% (27 episodes). In addition an overall rate of hesitation was 5.8% (26 episodes). There was no statistically significant difference in error rates with the 2 hand washbasin configurations. The amelioration of causes of error and hesitation by standardization of the appearance and relative positioning of hand hygiene solutions at washbasins may translate in to improved hand hygiene behaviors. Placement of moisturizer at the washbasin may not be essential. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Comparison of the efficacy and technical accuracy of different rectangular collimators for intraoral radiography.

PubMed

Zhang, Wenjian; Abramovitch, Kenneth; Thames, Walter; Leon, Inga-Lill K; Colosi, Dan C; Goren, Arthur D

2009-07-01

The objective of this study was to compare the operating efficiency and technical accuracy of 3 different rectangular collimators. A full-mouth intraoral radiographic series excluding central incisor views were taken on training manikins by 2 groups of undergraduate dental and dental hygiene students. Three types of rectangular collimator were used: Type I ("free-hand"), Type II (mechanical interlocking), and Type III (magnetic collimator). Eighteen students exposed one side of the manikin with a Type I collimator and the other side with a Type II. Another 15 students exposed the manikin with Type I and Type III respectively. Type I is currently used for teaching and patient care at our institution and was considered as the control to which both Types II and III were compared. The time necessary to perform the procedure, subjective user friendliness, and the number of technique errors (placement, projection, and cone cut errors) were assessed. The Student t test or signed rank test was used to determine statistical difference (P

The effects of a test-taking strategy intervention for high school students with test anxiety in advanced placement science courses

NASA Astrophysics Data System (ADS)

Markus, Doron J.

Test anxiety is one of the most debilitating and disruptive factors associated with underachievement and failure in schools (Birenbaum, Menucha, Nasser, & Fadia, 1994; Tobias, 1985). Researchers have suggested that interventions that combine multiple test-anxiety reduction techniques are most effective at reducing test anxiety levels (Ergene, 2003). For the current study, involving 62 public high school students enrolled in advanced placement science courses, the researcher designed a multimodal intervention designed to reduce test anxiety. Analyses were conducted to assess the relationships among test anxiety levels, unit examination scores, and irregular multiple-choice error patterns (error clumping), as well as changes in these measures after the intervention. Results indicate significant, positive relationships between some measures of test anxiety and error clumping, as well as significant, negative relationships between test anxiety levels and student achievement. In addition, results show significant decreases in holistic measures of test anxiety among students with low anxiety levels, as well as decreases in Emotionality subscores of test anxiety among students with high levels of test anxiety. There were no significant changes over time in the Worry subscores of test anxiety. Suggestions for further research include further confirmation of the existence of error clumping, and its causal relationship with test anxiety.

Population-based risk for complications after transthoracic needle lung biopsy of a pulmonary nodule: an analysis of discharge records.

PubMed

Wiener, Renda Soylemez; Schwartz, Lisa M; Woloshin, Steven; Welch, H Gilbert

2011-08-02

Because pulmonary nodules are found in up to 25% of patients undergoing computed tomography of the chest, the question of whether to perform biopsy is becoming increasingly common. Data on complications after transthoracic needle lung biopsy are limited to case series from selected institutions. To determine population-based estimates of risks for complications after transthoracic needle biopsy of a pulmonary nodule. Cross-sectional analysis. The 2006 State Ambulatory Surgery Databases and State Inpatient Databases for California, Florida, Michigan, and New York from the Healthcare Cost and Utilization Project. 15 865 adults who had transthoracic needle biopsy of a pulmonary nodule. Percentage of biopsies complicated by hemorrhage, any pneumothorax, or pneumothorax requiring a chest tube, and adjusted odds ratios for these complications associated with various biopsy characteristics, calculated by using multivariate, population-averaged generalized estimating equations. Although hemorrhage was rare, complicating 1.0% (95% CI, 0.9% to 1.2%) of biopsies, 17.8% (CI, 11.8% to 23.8%) of patients with hemorrhage required a blood transfusion. In contrast, the risk for any pneumothorax was 15.0% (CI, 14.0% to 16.0%), and 6.6% (CI, 6.0% to 7.2%) of all biopsies resulted in pneumothorax requiring a chest tube. Compared with patients without complications, those who experienced hemorrhage or pneumothorax requiring a chest tube had longer lengths of stay (P < 0.001) and were more likely to develop respiratory failure requiring mechanical ventilation (P = 0.020). Patients aged 60 to 69 years (as opposed to younger or older patients), smokers, and those with chronic obstructive pulmonary disease had higher risk for complications. Estimated risks may be inaccurate if coding of complications is incomplete. The analyzed databases contain little clinical detail (such as information on nodule characteristics or biopsy pathology) and cannot indicate whether performing the biopsy produced useful information. Whereas hemorrhage is an infrequent complication of transthoracic needle lung biopsy, pneumothorax is common and often necessitates chest tube placement. These population-based data should help patients and physicians make more informed choices about whether to perform biopsy of a pulmonary nodule. Department of Veterans Affairs and National Cancer Institute.

Population-based risk of complications following transthoracic needle lung biopsy of a pulmonary nodule

PubMed Central

Wiener, Renda Soylemez; Schwartz, Lisa M.; Woloshin, Steven; Welch, H. Gilbert

2011-01-01

Background Because pulmonary nodules are found in up to 25% of patients undergoing chest computed tomography, the question of whether to biopsy is becoming increasingly common. Data on complications following transthoracic needle lung biopsy are limited to case series from selected institutions. Objective To determine population-based estimates of risks of complications following transthoracic needle biopsy of a pulmonary nodule. Design Cross-sectional analysis. Setting The 2006 Healthcare Cost and Utilization Project’s State Ambulatory Surgery Databases and State Inpatient Databases for California, Florida, Michigan, and New York. Patients 15,865 adults who underwent transthoracic needle biopsy of a pulmonary nodule. Measurements Percent of biopsies complicated by hemorrhage, any pneumothorax, and pneumothorax requiring chest tube, and adjusted odds ratios for these complications associated with various biopsy characteristics, calculated using multivariable population-averaged generalized estimating equations. Results Although hemorrhage was rare, complicating 1.0% (95% CI 0.9-1.2%) of biopsies, 17.8% (95% CI 11.8-23.8%) of patients with hemorrhage required a blood transfusion. By contrast, the risk of any pneumothorax was 15.0% (95% CI 14.0-16.0%), and 6.6% (95% CI 6.0-7.2%) of all biopsies resulted in a pneumothorax requiring chest tube. Compared to patients without complications, those who experienced hemorrhage or pneumothorax requiring chest tube had longer lengths of stay (p<0.001) and were more likely to develop respiratory failure requiring mechanical ventilation (p=0.02). Patients aged 60-69 years (as opposed to younger or older patients), smokers, and those with chronic obstructive pulmonary disease had higher risk of complications. Limitations Estimated risks may be inaccurate if coding of complications is incomplete. The databases analyzed contain little clinical detail (e.g., nodule characteristics, biopsy pathology) and cannot determine whether biopsies produced useful information. Conclusion While hemorrhage is an infrequent complication of transthoracic needle lung biopsy, pneumothorax is common and often necessitates chest tube placement. These population-based data should help patients and doctors make a more informed choice on whether to biopsy a pulmonary nodule. Primary Funding Source Department of Veterans Affairs and National Cancer Institute K07 CA 138772 PMID:21810706

[Gas tamponade following intraoperative pneumothorax on a single lung: A case study].

PubMed

El Jaouhari, S D; Mamane Nassirou, O; Meziane, M; Bensghir, M; Haimeur, C

2017-04-01

Intraoperative pneumothorax is a rare complication with a high risk of cardiorespiratory arrest by gas tamponade especially on a single lung. We report the case of a female patient aged 53 years who benefited from a left pneumonectomy on pulmonary tuberculosis sequelae. The patient presented early postoperative anemia with a left hemothorax requiring an emergency thoracotomy. In perioperative, the patient had a gas tamponade following a pneumothorax of the remaining lung, and the fate has been avoided by an exsufflation. Intraoperative pneumothorax can occur due to lesions of the tracheobronchial airway, of the brachial plexus, the placement of a central venous catheter or barotrauma. The diagnosis of pneumothorax during unipulmonary ventilation is posed by the sudden onset of hypoxia associated with increased airway pressures and hypercapnia. The immediate life-saving procedure involves fine needle exsufflation before the placement of a chest tube. Prevention involves reducing the risk of barotrauma by infusing patients with low flow volumes and the proper use of positive airway pressure, knowing that despite protective ventilation, barotraumas risk still exists. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

T-tube drainage of the common bile duct choleperitoneum: etiology and management.

PubMed

Daldoul, S; Moussi, A; Zaouche, A

2012-06-01

External drainage of the common bile duct by placement of a T-tube is a common practice after choledochotomy. This practice may result in the specific complication of bile peritonitis due to leakage after removal of the T-tube. This complication has multiple causes: some are patient-related (corticotherapy, chemotherapy, ascites), and others are due to technical factors (inappropriate suturing of the drain to the ductal wall, minimal inflammatory reaction related to some drain materials). The clinical presentation is quite variable depending on the amount and rapidity of intra-peritoneal spread of of bile leakage. Abdominal ultrasound (US), with US-guided needle aspiration and occasionally Technetium(99) scintigraphy are useful for diagnosis. Traditional therapy consists of surgical intervention including peritoneal lavage and re-intubation of the choledochal fistulous tract to allow for a further period of external drainage. When leakage is walled off and well-tolerated, a more nuanced and less invasive conservative therapy may combine percutaneous drainage with endoscopic placement of a trans-ampullary biliary drainage. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Injection-depth-locking axial motion guided handheld micro-injector using CP-SSOCT.

PubMed

Cheon, Gyeong Woo; Huang, Yong; Kwag, Hye Rin; Kim, Ki-Young; Taylor, Russell H; Gehlbach, Peter L; Kang, Jin U

2014-01-01

This paper presents a handheld micro-injector system using common-path swept source optical coherence tomography (CP-SSOCT) as a distal sensor with highly accurate injection-depth-locking. To achieve real-time, highly precise, and intuitive freehand control, the system used graphics processing unit (GPU) to process the oversampled OCT signal with high throughput and a smart customized motion monitoring control algorithm. A performance evaluation was conducted with 60-insertions and fluorescein dye injection tests to show how accurately the system can guide the needle and lock to the target depth. The evaluation tests show our system can guide the injection needle into the desired depth with 4.12 um average deviation error while injecting 50 nl of fluorescein dye.

EPE fundamentals and impact of EUV: Will traditional design-rule calculations work in the era of EUV?

NASA Astrophysics Data System (ADS)

Gabor, Allen H.; Brendler, Andrew C.; Brunner, Timothy A.; Chen, Xuemei; Culp, James A.; Levinson, Harry J.

2018-03-01

The relationship between edge placement error, semiconductor design-rule determination and predicted yield in the era of EUV lithography is examined. This paper starts with the basics of edge placement error and then builds up to design-rule calculations. We show that edge placement error (EPE) definitions can be used as the building blocks for design-rule equations but that in the last several years the term "EPE" has been used in the literature to refer to many patterning errors that are not EPE. We then explore the concept of "Good Fields"1 and use it predict the n-sigma value needed for design-rule determination. Specifically, fundamental yield calculations based on the failure opportunities per chip are used to determine at what n-sigma "value" design-rules need to be tested to ensure high yield. The "value" can be a space between two features, an intersect area between two features, a minimum area of a feature, etc. It is shown that across chip variation of design-rule important values needs to be tested at sigma values between seven and eight which is much higher than the four-sigma values traditionally used for design-rule determination. After recommending new statistics be used for design-rule calculations the paper examines the impact of EUV lithography on sources of variation important for design-rule calculations. We show that stochastics can be treated as an effective dose variation that is fully sampled across every chip. Combining the increased within chip variation from EUV with the understanding that across chip variation of design-rule important values needs to not cause a yield loss at significantly higher sigma values than have traditionally been looked at, the conclusion is reached that across-wafer, wafer-to-wafer and lot-to-lot variation will have to overscale for any technology introducing EUV lithography where stochastic noise is a significant fraction of the effective dose variation. We will emphasize stochastic effects on edge placement error distributions and appropriate design-rule setting. While CD distributions with long tails coming from stochastic effects do bring increased risk of failure (especially on chips that may have over a billion failure opportunities per layer) there are other sources of variation that have sharp cutoffs, i.e. have no tails. We will review these sources and show how distributions with different skew and kurtosis values combine.

Real-time self-calibration of a tracked augmented reality display

NASA Astrophysics Data System (ADS)

Baum, Zachary; Lasso, Andras; Ungi, Tamas; Fichtinger, Gabor

2016-03-01

PURPOSE: Augmented reality systems have been proposed for image-guided needle interventions but they have not become widely used in clinical practice due to restrictions such as limited portability, low display refresh rates, and tedious calibration procedures. We propose a handheld tablet-based self-calibrating image overlay system. METHODS: A modular handheld augmented reality viewbox was constructed from a tablet computer and a semi-transparent mirror. A consistent and precise self-calibration method, without the use of any temporary markers, was designed to achieve an accurate calibration of the system. Markers attached to the viewbox and patient are simultaneously tracked using an optical pose tracker to report the position of the patient with respect to a displayed image plane that is visualized in real-time. The software was built using the open-source 3D Slicer application platform's SlicerIGT extension and the PLUS toolkit. RESULTS: The accuracy of the image overlay with image-guided needle interventions yielded a mean absolute position error of 0.99 mm (95th percentile 1.93 mm) in-plane of the overlay and a mean absolute position error of 0.61 mm (95th percentile 1.19 mm) out-of-plane. This accuracy is clinically acceptable for tool guidance during various procedures, such as musculoskeletal injections. CONCLUSION: A self-calibration method was developed and evaluated for a tracked augmented reality display. The results show potential for the use of handheld image overlays in clinical studies with image-guided needle interventions.

Source strength verification and quality assurance of preloaded brachytherapy needles using a CMOS flat panel detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golshan, Maryam, E-mail: maryam.golshan@bccancer.bc.ca; Spadinger, Ingrid; Chng, Nick

2016-06-15

Purpose: Current methods of low dose rate brachytherapy source strength verification for sources preloaded into needles consist of either assaying a small number of seeds from a separate sample belonging to the same lot used to load the needles or performing batch assays of a subset of the preloaded seed trains. Both of these methods are cumbersome and have the limitations inherent to sampling. The purpose of this work was to investigate an alternative approach that uses an image-based, autoradiographic system capable of the rapid and complete assay of all sources without compromising sterility. Methods: The system consists of amore » flat panel image detector, an autoclavable needle holder, and software to analyze the detected signals. The needle holder was designed to maintain a fixed vertical spacing between the needles and the image detector, and to collimate the emissions from each seed. It also provides a sterile barrier between the needles and the imager. The image detector has a sufficiently large image capture area to allow several needles to be analyzed simultaneously.Several tests were performed to assess the accuracy and reproducibility of source strengths obtained using this system. Three different seed models (Oncura 6711 and 9011 {sup 125}I seeds, and IsoAid Advantage {sup 103}Pd seeds) were used in the evaluations. Seeds were loaded into trains with at least 1 cm spacing. Results: Using our system, it was possible to obtain linear calibration curves with coverage factor k = 1 prediction intervals of less than ±2% near the centre of their range for the three source models. The uncertainty budget calculated from a combination of type A and type B estimates of potential sources of error was somewhat larger, yielding (k = 1) combined uncertainties for individual seed readings of 6.2% for {sup 125}I 6711 seeds, 4.7% for {sup 125}I 9011 seeds, and 11.0% for Advantage {sup 103}Pd seeds. Conclusions: This study showed that a flat panel detector dosimetry system is a viable option for source strength verification in preloaded needles, as it is capable of measuring all of the sources intended for implantation. Such a system has the potential to directly and efficiently estimate individual source strengths, the overall mean source strength, and the positions within the seed-spacer train.« less

Portable Optical Epidural Needle-A CMOS-Based System Solution and Its Circuit Design

PubMed Central

Gong, Cihun-Siyong Alex; Lin, Shih-Pin; Mandell, M. Susan; Tsou, Mei-Yung; Chang, Yin; Ting, Chien-Kun

2014-01-01

Epidural anesthesia is a common anesthesia method yet up to 10% of procedures fail to provide adequate analgesia. This is usually due to misinterpreting the tactile information derived from the advancing needle through the complex tissue planes. Incorrect placement also can cause dural puncture and neural injury. We developed an optic system capable of reliably identifying tissue planes surrounding the epidural space. However the new technology was too large and cumbersome for practical clinical use. We present a miniaturized version of our optic system using chip technology (first generation CMOS-based system) for logic functions. The new system was connected to an alarm that was triggered once the optic properties of the epidural were identified. The aims of this study were to test our miniaturized system in a porcine model and describe the technology to build this new clinical tool. Our system was tested in a porcine model and identified the epidural space in the lumbar, low and high thoracic regions of the spine. The new technology identified the epidural space in all but 1 of 46 attempts. Experimental results from our fabricated integrated circuit and animal study show the new tool has future clinical potential. PMID:25162150

Sigmoid irrigation tube for the management of chronic evacuation disorders.

PubMed

Gauderer, Michael W L; Decou, James M; Boyle, John T

2002-03-01

Antegrade colonic irrigation, in which the right colon is accessed via appendicostomy or cecostomy, now is an important adjunct in the management of children with chronic evacuation disorders. However, in most children, the major area of dysfunction is the left rather than the right colon. The authors developed a simple, percutaneous endoscopic, laparoscopically controlled sigmoid irrigation tube placement and evaluated the results in 4 children. A rigid sigmoidoscope is advanced into the upper sigmoid and the loop brought in contact with the abdominal wall under laparoscopic control. A small skin incision is made and a needle pushed across the abdominal and sigmoid walls into the lumen of the sigmoidoscope. A guide wire is advanced through the needle into the scope and retrieved. After the scope is removed, a PEG-type catheter is attached to the guide wire and pulled back, securing the sigmoid loop to the abdominal wall. The tube is subsequently converted to a skin-level device by simply adding an external port valve. All 4 patients achieved prompt evacuation in the sitting position. Sigmoid tube for antegrade irrigation is an appealing alternative to conventional cecal access. The procedure is simple and may offer physiologic advantages. Copyright 2002 by W.B. Saunders Company.

Investigation of an intelligent system for fiber optic-based epidural anesthesia.

PubMed

Gong, Cihun-Siyong Alex; Ting, Chien-Kun

2014-01-01

Even though there have been many approaches to assist the anesthesiologists in performing regional anesthesia, none of the prior arts may be said as an unrestricted technique. The lack of a design that is with sufficient sensitivity to the targets of interest and automatic indication of needle placement makes it difficult to all-round implementation of field usage of objectiveness. In addition, light-weight easy-to-use realization is the key point of portability. This paper reports on an intelligent system of epidural space identification using optical technique, with particular emphasis on efficiency-enhanced aspects. Statistical algorithms, implemented in a dedicated field-programmable hardware platform along with an on-platform application-specific integrated chip, used to advance real-time self decision making in needle advancement are discussed together with the feedback results. Clinicians' viewpoint of improving the correct rate of our technique is explained in detail. Our study demonstrates not only that the improved system is able to behave as if it is a skillful anesthesiologist but also it has potential to bring promising assist into clinical use under varied conditions and small amount of sample, provided that several concerns are addressed.

Sampling design and required sample size for evaluating contamination levels of 137Cs in Japanese fir needles in a mixed deciduous forest stand in Fukushima, Japan.

PubMed

Oba, Yurika; Yamada, Toshihiro

2017-05-01

We estimated the sample size (the number of samples) required to evaluate the concentration of radiocesium ( 137 Cs) in Japanese fir (Abies firma Sieb. & Zucc.), 5 years after the outbreak of the Fukushima Daiichi Nuclear Power Plant accident. We investigated the spatial structure of the contamination levels in this species growing in a mixed deciduous broadleaf and evergreen coniferous forest stand. We sampled 40 saplings with a tree height of 150 cm-250 cm in a Fukushima forest community. The results showed that: (1) there was no correlation between the 137 Cs concentration in needles and soil, and (2) the difference in the spatial distribution pattern of 137 Cs concentration between needles and soil suggest that the contribution of root uptake to 137 Cs in new needles of this species may be minor in the 5 years after the radionuclides were released into the atmosphere. The concentration of 137 Cs in needles showed a strong positive spatial autocorrelation in the distance class from 0 to 2.5 m, suggesting that the statistical analysis of data should consider spatial autocorrelation in the case of an assessment of the radioactive contamination of forest trees. According to our sample size analysis, a sample size of seven trees was required to determine the mean contamination level within an error in the means of no more than 10%. This required sample size may be feasible for most sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath.

PubMed

Lopez, A M; Sala-Blanch, X; Castillo, R; Hadzic, A

2014-01-01

The recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath. Thirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n=16) or a peri-sheath block (n=18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30mL were used in both groups. The progression of motor and sensory block was assessed at 5min intervals. Duration of block was recorded. Adequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1±7.4min vs. 19.0±4.0; p<.001). Our study suggests that for successful sciatic popliteal block in less than 30min, local anesthetic should be injected within the sheath. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

[Comparison of transverse short-axis classic and oblique long-axis "Syringe-Free" approaches for internal jugular venous catheterization under ultrasound guidance].

PubMed

Ince, Ilker; Arı, Muhammet Ali; Sulak, Muhammet Mustafa; Aksoy, Mehmet

There are different ultrasound probe positions used for internal jugular venous catheter placement. Also, in-plane or out of plane needle approach may be used for catheterization. Transverse short-axis classic approach is the most popular performed approach in literature. "Syringe-Free" is a new described technique that is performed with oblique long-axis approach. We aimed to compare performance of these two approaches. This study was conducted as a prospective and randomized study. 80 patients were included the study and divided into two groups that were named Group C (transverse short-axis classic approach) and Group SF (oblique long-axis syringe-free approach) by a computer-generated randomization. The primary outcome was mean time that guidewire is seen in the internal jugular vein (performing time). The secondary outcomes were to compare number of needle pass, number of skin puncture and complications between two groups. Demographic and hemodynamic data were not significantly different. The mean performing time was 54.9±19.1s in Group C and 43.9±15.8s in Group SF. Significant differences were found between the groups (p=0.006). Mean number of needle pass was 3.2(±2.1) in Group C and 2.1(±1.6) in Group SF. There were statistically significant differences between two groups (p=0.002). The number of skin puncture was 1.6(±0.8) and 1.2(±0.5) in Group C and SF, respectively (p=0.027). "Syringe-Free" technique has lower performing time, number of needle pass and skin puncture. Also, it allows to follow progress of guide-wire under continuous ultrasound visualization and the procedure does not need assistance during catheter insertion. Namely, "Syringe-Free" is effective, safe and fast technique that may be used to place internal jugular venous catheter. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Spatio-Temporal Field Estimation Using Kriged Kalman Filter (KKF) with Sparsity-Enforcing Sensor Placement.

PubMed

Roy, Venkat; Simonetto, Andrea; Leus, Geert

2018-06-01

We propose a sensor placement method for spatio-temporal field estimation based on a kriged Kalman filter (KKF) using a network of static or mobile sensors. The developed framework dynamically designs the optimal constellation to place the sensors. We combine the estimation error (for the stationary as well as non-stationary component of the field) minimization problem with a sparsity-enforcing penalty to design the optimal sensor constellation in an economic manner. The developed sensor placement method can be directly used for a general class of covariance matrices (ill-conditioned or well-conditioned) modelling the spatial variability of the stationary component of the field, which acts as a correlated observation noise, while estimating the non-stationary component of the field. Finally, a KKF estimator is used to estimate the field using the measurements from the selected sensing locations. Numerical results are provided to exhibit the feasibility of the proposed dynamic sensor placement followed by the KKF estimation method.

Uncertainty Analysis of Seebeck Coefficient and Electrical Resistivity Characterization

NASA Technical Reports Server (NTRS)

Mackey, Jon; Sehirlioglu, Alp; Dynys, Fred

2014-01-01

In order to provide a complete description of a materials thermoelectric power factor, in addition to the measured nominal value, an uncertainty interval is required. The uncertainty may contain sources of measurement error including systematic bias error and precision error of a statistical nature. The work focuses specifically on the popular ZEM-3 (Ulvac Technologies) measurement system, but the methods apply to any measurement system. The analysis accounts for sources of systematic error including sample preparation tolerance, measurement probe placement, thermocouple cold-finger effect, and measurement parameters; in addition to including uncertainty of a statistical nature. Complete uncertainty analysis of a measurement system allows for more reliable comparison of measurement data between laboratories.

CT Fluoroscopy-Guided Transsacral Intervertebral Drainage for Pyogenic Spondylodiscitis at the Lumbosacral Junction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, Tomohiro, E-mail: t-matsu@tokai-u.jp; Mine, Takahiko, E-mail: mine@tsc.u-tokai.ac.jp; Hayashi, Toshihiko, E-mail: t.hayashi@tokai.ac.jp

PurposeTo retrospectively describe the feasibility and efficacy of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction with a combination of two interventional radiological techniques—CT-guided bone biopsy and abscess drainage.Materials and methodsThree patients with pyogenic spondylodiscitis at the lumbosacral junction were enrolled in this study between July 2013 and December 2015. The procedure of CT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction was as follows: the sacrum at S1 pedicle was penetrated with an 11-gauge (G) bone biopsy needle to create a path for an 8-French (F) pigtail drainage catheter. The bone biopsymore » needle was withdrawn, and an 18-G needle was inserted into the intervertebral space of the lumbosacral junction. Then, a 0.038-inch guidewire was inserted into the intervertebral space. Finally, the 8-F pigtail drainage catheter was inserted over the guidewire until its tip reached the intervertebral space. All patients received six-week antibiotics treatment.ResultsSuccessful placement of the drainage catheter was achieved for each patient without procedural complications. The duration of drainage was 17–33 days. For two patients, specific organisms were isolated; thus, definitive medical therapy was possible. All patients responded well to the treatment.ConclusionsCT fluoroscopy-guided transsacral intervertebral drainage for pyogenic spondylodiscitis at the lumbosacral junction is feasible and can be effective with a combination of two interventional techniques—CT fluoroscopy-guided bone biopsy and abscess drainage.« less

Blindness following cosmetic injections of the face.

PubMed

Lazzeri, Davide; Agostini, Tommaso; Figus, Michele; Nardi, Marco; Pantaloni, Marcello; Lazzeri, Stefano

2012-04-01

Complications following facial cosmetic injections have recently heightened awareness of the possibility of iatrogenic blindness. The authors conducted a systematic review of the available literature to provide the best evidence for the prevention and treatment of this serious eye injury. The authors included in the study only the cases in which blindness was a direct consequence of a cosmetic injection procedure of the face. Twenty-nine articles describing 32 patients were identified. In 15 patients, blindness occurred after injections of adipose tissue; in the other 17, it followed injections of various materials, including corticosteroids, paraffin, silicone oil, bovine collagen, polymethylmethacrylate, hyaluronic acid, and calcium hydroxyapatite. Some precautions may minimize the risk of embolization of filler into the ophthalmic artery following facial cosmetic injections. Intravascular placement of the needle or cannula should be demonstrated by aspiration before injection and should be further prevented by application of local vasoconstrictor. Needles, syringes, and cannulas of small size should be preferred to larger ones and be replaced with blunt flexible needles and microcannulas when possible. Low-pressure injections with the release of the least amount of substance possible should be considered safer than bolus injections. The total volume of filler injected during the entire treatment session should be limited, and injections into pretraumatized tissues should be avoided. Actually, no safe, feasible, and reliable treatment exists for iatrogenic retinal embolism. Nonetheless, therapy should theoretically be directed to lowering intraocular pressure to dislodge the embolus into more peripheral vessels of the retinal circulation, increasing retinal perfusion and oxygen delivery to hypoxic tissues. Risk, V.

Quality Control of High-Dose-Rate Brachytherapy: Treatment Delivery Analysis Using Statistical Process Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Able, Charles M., E-mail: cable@wfubmc.edu; Bright, Megan; Frizzell, Bart

Purpose: Statistical process control (SPC) is a quality control method used to ensure that a process is well controlled and operates with little variation. This study determined whether SPC was a viable technique for evaluating the proper operation of a high-dose-rate (HDR) brachytherapy treatment delivery system. Methods and Materials: A surrogate prostate patient was developed using Vyse ordnance gelatin. A total of 10 metal oxide semiconductor field-effect transistors (MOSFETs) were placed from prostate base to apex. Computed tomography guidance was used to accurately position the first detector in each train at the base. The plan consisted of 12 needles withmore » 129 dwell positions delivering a prescribed peripheral dose of 200 cGy. Sixteen accurate treatment trials were delivered as planned. Subsequently, a number of treatments were delivered with errors introduced, including wrong patient, wrong source calibration, wrong connection sequence, single needle displaced inferiorly 5 mm, and entire implant displaced 2 mm and 4 mm inferiorly. Two process behavior charts (PBC), an individual and a moving range chart, were developed for each dosimeter location. Results: There were 4 false positives resulting from 160 measurements from 16 accurately delivered treatments. For the inaccurately delivered treatments, the PBC indicated that measurements made at the periphery and apex (regions of high-dose gradient) were much more sensitive to treatment delivery errors. All errors introduced were correctly identified by either the individual or the moving range PBC in the apex region. Measurements at the urethra and base were less sensitive to errors. Conclusions: SPC is a viable method for assessing the quality of HDR treatment delivery. Further development is necessary to determine the most effective dose sampling, to ensure reproducible evaluation of treatment delivery accuracy.« less

Including sheath effects in the interpretation of planar retarding potential analyzer's low-energy ion data

NASA Astrophysics Data System (ADS)

Fisher, L. E.; Lynch, K. A.; Fernandes, P. A.; Bekkeng, T. A.; Moen, J.; Zettergren, M.; Miceli, R. J.; Powell, S.; Lessard, M. R.; Horak, P.

2016-04-01

The interpretation of planar retarding potential analyzers (RPA) during ionospheric sounding rocket missions requires modeling the thick 3D plasma sheath. This paper overviews the theory of RPAs with an emphasis placed on the impact of the sheath on current-voltage (I-V) curves. It then describes the Petite Ion Probe (PIP) which has been designed to function in this difficult regime. The data analysis procedure for this instrument is discussed in detail. Data analysis begins by modeling the sheath with the Spacecraft Plasma Interaction System (SPIS), a particle-in-cell code. Test particles are traced through the sheath and detector to determine the detector's response. A training set is constructed from these simulated curves for a support vector regression analysis which relates the properties of the I-V curve to the properties of the plasma. The first in situ use of the PIPs occurred during the MICA sounding rocket mission which launched from Poker Flat, Alaska in February of 2012. These data are presented as a case study, providing valuable cross-instrument comparisons. A heritage top-hat thermal ion electrostatic analyzer, called the HT, and a multi-needle Langmuir probe have been used to validate both the PIPs and the data analysis method. Compared to the HT, the PIP ion temperature measurements agree with a root-mean-square error of 0.023 eV. These two instruments agree on the parallel-to-B plasma flow velocity with a root-mean-square error of 130 m/s. The PIP with its field of view aligned perpendicular-to-B provided a density measurement with an 11% error compared to the multi-needle Langmuir Probe. Higher error in the other PIP's density measurement is likely due to simplifications in the SPIS model geometry.

Needle trap extraction for GC analysis of formic and acetic acids in aqueous solution.

PubMed

Lee, Xinqing; Huang, Daikuan; Lou, Dawei; Pawliszyn, Janusz

2012-07-01

Formic and acetic acids are ubiquitous in the environment, food, and most of the natural products. Extraction of the acids from aqueous solution is required for their isotope analysis by the gas chromatography-isotope ratio mass spectrometry. To this objective, we have previously developed a purge-and-trap technique using the dynamic solid-phase microextraction technology, the NeedlEX. The extraction efficiency, however, remains unexamined. Here, we address this question using the flame ionization detector and isotope ratio mass spectrometer while comparing it with that of the CAR/PDMS fiber. The results show that the NeedlEX is applicable at a wide range of concentration through coordination of purge volume given the minimum amount 3.7 ng and 1.8 ng of formic and acetic, respectively, is extracted. The efficiency of NeedlEX was 6-7 times lower than the fiber at 1000 μg/mL depending on the analyte. It is, however, superior to the latter at 10 μg/mL or less owing to its lower detection limit. The extraction efficiency of both acids is equivalent in molar amount. This is, however, disguised by the different response of the flame ionization detector. The isotope ratio mass spectrometor overcomes this problem but is compromised by relatively large errors. These results are particularly useful for isotopic analysis of carboxylic acids. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The mid-sternal length, a practical anatomical landmark for optimal positioning of long-term central venous catheters

PubMed Central

Salimi, Fereshte; Imani, Mohammad Reza; Ghasemi, Navab; Keshavarzian, Amir; Jazi, Amir Hosein Davarpanah

2013-01-01

Background: Long-term tunneled catheters are used for the hemodialysis or chemotherapy in many patients. Proper placement of the catheter tip could reduce early and late catheter related complications. Aim of the present study was to evaluate a new formula for proper placement of tunneled hemodialysis or infusion port device by using an external anatomic landmark. Materials and Methods: A total of 64 adult patients undergoing elective placement of tunneled Central Venous Catheter (CVC) requiring hemodialysis or chemotherapy were enrolled in this prospective study during 2011-2012 in the university hospital. The catheter length to be inserted in the right internal jugular vein (IJV) was calculated by adding two measurements (the shortest straight length between the insertion point of the needle and the suprasternal notch plus and half of sternal length). The catheter position was considered correct if the tip was positioned in the right atrium (RA) or Superior vena cava (SVC)-RA junction. Results: The patients were 55.28 ± 19.85 years of age, weighed 5.78 ± 16.62 kg and were 166.07 ± 10.27 cm tall. Catheters were inserted successfully in 88% of patients (n = 56). Catheter tip positions in the failures were SVC (n = 5), tricuspid valve (n = 2), and right ventricle (n = 1) in our patients. Conclusion: Long-term hemodialysis or port CVC could easily insert in the right IJV by using half of the sternal length as an external land marks among adult patients. PMID:24174941

Magnetic resonance imaging-targeted, 3D transrectal ultrasound-guided fusion biopsy for prostate cancer: Quantifying the impact of needle delivery error on diagnosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Peter R., E-mail: pmarti46@uwo.ca; Cool, Derek W.; Romagnoli, Cesare

2014-07-15

Purpose: Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided “fusion” prostate biopsy intends to reduce the ∼23% false negative rate of clinical two-dimensional TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsies continue to yield false negatives. Therefore, the authors propose to investigate how biopsy system needle delivery error affects the probability of sampling each tumor, by accounting for uncertainties due to guidance system error, image registration error, and irregular tumor shapes. Methods: T2-weighted, dynamic contrast-enhanced T1-weighted, and diffusion-weighted prostate MRI and 3D TRUS images were obtained from 49 patients. A radiologist and radiologymore » resident contoured 81 suspicious regions, yielding 3D tumor surfaces that were registered to the 3D TRUS images using an iterative closest point prostate surface-based method to yield 3D binary images of the suspicious regions in the TRUS context. The probabilityP of obtaining a sample of tumor tissue in one biopsy core was calculated by integrating a 3D Gaussian distribution over each suspicious region domain. Next, the authors performed an exhaustive search to determine the maximum root mean squared error (RMSE, in mm) of a biopsy system that gives P ≥ 95% for each tumor sample, and then repeated this procedure for equal-volume spheres corresponding to each tumor sample. Finally, the authors investigated the effect of probe-axis-direction error on measured tumor burden by studying the relationship between the error and estimated percentage of core involvement. Results: Given a 3.5 mm RMSE for contemporary fusion biopsy systems,P ≥ 95% for 21 out of 81 tumors. The authors determined that for a biopsy system with 3.5 mm RMSE, one cannot expect to sample tumors of approximately 1 cm{sup 3} or smaller with 95% probability with only one biopsy core. The predicted maximum RMSE giving P ≥ 95% for each tumor was consistently greater when using spherical tumor shapes as opposed to no shape assumption. However, an assumption of spherical tumor shape for RMSE = 3.5 mm led to a mean overestimation of tumor sampling probabilities of 3%, implying that assuming spherical tumor shape may be reasonable for many prostate tumors. The authors also determined that a biopsy system would need to have a RMS needle delivery error of no more than 1.6 mm in order to sample 95% of tumors with one core. The authors’ experiments also indicated that the effect of axial-direction error on the measured tumor burden was mitigated by the 18 mm core length at 3.5 mm RMSE. Conclusions: For biopsy systems with RMSE ≥ 3.5 mm, more than one biopsy core must be taken from the majority of tumors to achieveP ≥ 95%. These observations support the authors’ perspective that some tumors of clinically significant sizes may require more than one biopsy attempt in order to be sampled during the first biopsy session. This motivates the authors’ ongoing development of an approach to optimize biopsy plans with the aim of achieving a desired probability of obtaining a sample from each tumor, while minimizing the number of biopsies. Optimized planning of within-tumor targets for MRI-3D TRUS fusion biopsy could support earlier diagnosis of prostate cancer while it remains localized to the gland and curable.« less

In vivo thermoluminescence dosimetry dose verification of transperineal 192Ir high-dose-rate brachytherapy using CT-based planning for the treatment of prostate cancer.

PubMed

Anagnostopoulos, G; Baltas, D; Geretschlaeger, A; Martin, T; Papagiannis, P; Tselis, N; Zamboglou, N

2003-11-15

To evaluate the potential of in vivo thermoluminescence dosimetry to estimate the accuracy of dose delivery in conformal high-dose-rate brachytherapy of prostate cancer. A total of 50 LiF, TLD-100 cylindrical rods were calibrated in the dose range of interest and used as a batch for all fractions. Fourteen dosimeters for every treatment fraction were loaded in a plastic 4F catheter that was fixed in either one of the 6F needles implanted for treatment purposes or in an extra needle implanted after consulting with the patient. The 6F needles were placed either close to the urethra or in the vicinity of the median posterior wall of the prostate. Initial results are presented for 18 treatment fractions in 5 patients and compared to corresponding data calculated using the commercial treatment planning system used for the planning of the treatments based on CT images acquired postimplantation. The maximum observed mean difference between planned and delivered dose within a single treatment fraction was 8.57% +/- 2.61% (root mean square [RMS] errors from 4.03% to 9.73%). Corresponding values obtained after averaging results over all fractions of a patient were 6.88% +/- 4.93% (RMS errors from 4.82% to 7.32%). Experimental results of each fraction corresponding to the same patient point were found to agree within experimental uncertainties. Experimental results indicate that the proposed method is feasible for dose verification purposes and suggest that dose delivery in transperineal high-dose-rate brachytherapy after CT-based planning can be of acceptable accuracy.

Multimodal US-gamma imaging using collaborative robotics for cancer staging biopsies.

PubMed

Esposito, Marco; Busam, Benjamin; Hennersperger, Christoph; Rackerseder, Julia; Navab, Nassir; Frisch, Benjamin

2016-09-01

The staging of female breast cancer requires detailed information about the level of cancer spread through the lymphatic system. Common practice to obtain this information for patients with early-stage cancer is sentinel lymph node (SLN) biopsy, where LNs are radioactively identified for surgical removal and subsequent histological analysis. Punch needle biopsy is a less invasive approach but suffers from the lack of combined anatomical and nuclear information. We present and evaluate a system that introduces live collaborative robotic 2D gamma imaging in addition to live 2D ultrasound to identify SLNs in the surrounding anatomy. The system consists of a robotic arm equipped with both a gamma camera and a stereoscopic tracking system that monitors the position of an ultrasound probe operated by the physician. The arm cooperatively places the gamma camera parallel to the ultrasound imaging plane to provide live multimodal visualization and guidance. We validate the system by evaluating the target registration errors between fused nuclear and US image data in a phantom consisting of two spheres, one of which is filled with radioactivity. Medical experts perform punch biopsies on agar-gelatine phantoms with complex configurations of hot and cold lesions to provide a qualitative and quantitative evaluation of the system. The average point registration error for the overlay is [Formula: see text] mm. The time of the entire procedure was reduced by 36 %, with 80v of the biopsies being successful. The users' feedback was very positive, and the system was deemed to be very intuitive, with handling similar to classic US-guided needle biopsy. We present and evaluate the first medical collaborative robotic imaging system. Feedback from potential users for SLN punch needle biopsy is encouraging. Ongoing work investigates the clinical feasibility with more complex and realistic phantoms.

Method for measuring target rotation angle by theodolites

NASA Astrophysics Data System (ADS)

Sun, Zelin; Wang, Zhao; Zhai, Huanchun; Yang, Xiaoxu

2013-05-01

To overcome the disadvantage of the current measurement methods using theodolites in an environment with shock and long working hours and so on, this paper proposes a new method for 3D coordinate measurement that is based on an immovable measuring coordinate system. According to the measuring principle, the mathematics model is established and the measurement uncertainty is analysed. The measurement uncertainty of the new method is a function of the theodolite observation angles and their uncertainty, and can be reduced by optimizing the theodolites’ placement. Compared to other methods, this method allows the theodolite positions to be changed in the measuring process, and mutual collimation between the theodolites is not required. The experimental results show that the measurement model and the optimal placement principle are correct, and the measurement error is less than 0.01° after optimizing the theodolites’ placement.

Accuracy of Novel Computed Tomography-Guided Frameless Stereotactic Drilling and Catheter System in Human Cadavers.

PubMed

Sankey, Eric W; Butler, Eric; Sampson, John H

2017-10-01

To evaluate accuracy of a computed tomography (CT)-guided frameless stereotactic drilling and catheter system. A prospective, single-arm study was performed using human cadaver heads to evaluate placement accuracy of a novel, flexible intracranial catheter and stabilizing bone anchor system and drill kit. There were 20 catheter placements included in the analysis. The primary endpoint was accuracy of catheter tip location on intraoperative CT. Secondary endpoints included target registration error and entry and target point error before and after drilling. Measurements are reported as mean ± SD (median, range). Target registration error was 0.46 mm ± 0.26 (0.50 mm, -1.00 to 1.00 mm). Two (10%) target point trajectories were negatively impacted by drilling. Intracranial catheter depth was 59.8 mm ± 9.4 (60.5 mm, 38.0-80.0 mm). Drilling angle was 22° ± 9 (21°, 7°-45°). Deviation between planned and actual entry point on CT was 1.04 mm ± 0.38 (1.00 mm, 0.40-2.00 mm). Deviation between planned and actual target point on CT was 1.60 mm ± 0.98 (1.40 mm, 0.40-4.00 mm). No correlation was observed between intracranial catheter depth and target point deviation (accuracy) (Pearson coefficient 0.018) or between technician experience and accuracy (Pearson coefficient 0.020). There was no significant difference in accuracy with trajectories performed for different cadaver heads (P = 0.362). Highly accurate catheter placement is achievable using this novel flexible catheter and bone anchor system placed via frameless stereotaxy, with an average deviation between planned and actual target point of 1.60 mm ± 0.98 (1.40 mm, 0.40-4.00 mm). Copyright © 2017 Elsevier Inc. All rights reserved.

An easy to produce and economical three-dimensional brain phantom for stereotactic computed tomographic-guided brain biopsy training in the dog.

PubMed

Sidhu, Deepinder S; Ruth, Jeffrey D; Lambert, Gregory; Rossmeisl, John H

2017-07-01

To develop and validate a three-dimensional (3D) brain phantom that can be incorporated into existing stereotactic headframes to simulate stereotactic brain biopsy (SBB) and train veterinary surgeons. Experimental study. Canine brain phantoms were fabricated from osteological skull specimens, agarose brain parenchyma, and cheddar and mozzarella cheese molds (simulating meningiomas and gliomas). The neuroradiologic and viscoelastic properties of phantoms were quantified with computed tomography (CT) and oscillatory compression tests, respectively. Phantoms were validated by experienced and novice operators performing SBB on phantoms containing randomly placed, focal targets. Target yield and needle placement error (NPE) were compared between operators. Phantoms were produced in <4 hours, at an average cost of $92. The CT appearances of the phantom skull, agarose, and cheese components approximated the in vivo features of skull, brain parenchyma, and contrast-enhancing tumors of meningeal and glial origin, respectively. The complex moduli of the agarose and cheeses were comparable to the viscoelastic properties of in vivo brain tissues and brain tumors. The overall diagnostic yield of SBB was 88%. Although NPE did not differ between novice (median 3.68 mm; range, 1.46-14.54 mm) and experienced surgeons (median 1.17 mm, range, 0.78-1.58 mm), our results support the relevance of the learning curve associated with the SBB procedure. This 3D phantom replicates anatomical, CT, and tactile features of brain tissues and tumors and can be used to develop the technical skills required to perform SBB. © 2017 The American College of Veterinary Surgeons.

Comparison of Sonography versus Digital Breast Tomosynthesis to Locate Intramammary Marker Clips

PubMed Central

Schulz-Wendtland, R.; Dankerl, P.; Dilbat, G.; Bani, M.; Fasching, P. A.; Heusinger, K.; Lux, M. P.; Loehberg, C. R.; Jud, S. M.; Rauh, C.; Bayer, C. M.; Beckmann, M. W.; Wachter, D. L.; Uder, M.; Meier-Meitinger, M.; Brehm, B.

2015-01-01

Introduction: This study aimed to compare the accuracy of sonography versus digital breast tomosynthesis to locate intramammary marker clips placed under ultrasound guidance. Patients and Methods: Fifty patients with suspicion of breast cancer (lesion diameter less than 2 cm [cT1]) had ultrasound-guided core needle biopsy with placement of a marker clip in the center of the tumor. Intramammary marker clips were subsequently located with both sonography and digital breast tomosynthesis. Results: Sonography detected no dislocation of intrammammary marker clips in 42 of 50 patients (84 %); dislocation was reported in 8 patients (16 %) with a maximum dislocation of 7 mm along the x-, y- or z-axis. Digital breast tomosynthesis showed accurate placement without dislocation of the intramammary marker clip in 48 patients (96 %); 2 patients (4 %) had a maximum clip dislocation of 3 mm along the x-, y- or z-axis (p < 0.05). Conclusion: The use of digital breast tomosynthesis could improve the accuracy when locating intramammary marker clips compared to sonography and could, in future, be used to complement or even completely replace sonography. PMID:25684789

Design and preliminary accuracy studies of an MRI-guided transrectal prostate intervention system.

PubMed

Krieger, Axel; Csoma, Csaba; Iordachital, Iulian I; Guion, Peter; Singh, Anurag K; Fichtinger, Gabor; Whitcomb, Louis L

2007-01-01

This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery. The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration and subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders and mechanical scales. Targeting accuracy of the system is evaluated in prostate phantom experiments. Achieved targeting accuracy and procedure times were found to compare favorably with existing systems using passive and active tracking methods. Moreover, the portable design of the system using only standard MRI image sequences and minimal custom scanner interfacing allows the system to be easily used on different MRI scanners.

A simple customized surgical guide for orthodontic miniplates with tube.

PubMed

Paek, Janghyun; Su, Ming-Jeaun; Kwon, Soon-Yong; Kim, Seong-Hun; Chung, Kyu-Rhim; Nelson, Gerald

2012-09-01

This article reports the use of a customized surgical guide for simple and precise C-tube plate placement with minimized incision. Patients who were planning to have orthodontic miniplate treatment because of narrow interradicular space were recruited for this study. A combined silicone and stainless steel wire surgical guide for the C-tube was fabricated on the cast model. The taller wire of the positioning guide is used to accurately start the incision. The incision guide-wire position is verified by placing the miniplate on the coronal horizontal wire to confirm that the incision will coordinate with the screw holes. Because the miniplate is firmly held in place, there is no risk of the miniplate anchoring screws (diameter, 1.5 mm; length, 4 mm) sliding on the bone surface during placement with a manual hand driver. The surgical guide was placed on the clinical site, and it allowed precise placement of the miniplate with minimum incision and preventing from slippage or path-of-insertion angulation errors that might interfere with accurate placement. Customized surgical guide enables precise planning for miniplate positions in anatomically complex sites.

Application of an image-guided navigation system in breast cancer localization

NASA Astrophysics Data System (ADS)

Alderliesten, Tanja; Loo, Claudette; Schlief, Angelique T. E. F.; Paape, Anita; van der Meer, Michiel; Gilhuijs, Kenneth G. A.

2009-02-01

Image-guided navigation on the basis of pre-therapy images in a deformable organ, such as the breast, requires a survey of the factors that cause uncertainties. A deformable breast-tissue-mimicking phantom with simulated tumors was employed to investigate the accuracy of lesion localization with a needle instrument coupled to an optical measurement system. The RMS deviation was 1.1 mm with errors <= 2.0 mm in 96% of the procedures. Ultrasonography data acquired during needle localization of breast tumors were analyzed in 20 patients (23 tumors; 12 benign, 11 malignant) to investigate the deformation due to presence of instruments. The overall RMS tumor shift was 2.3 mm after release of pressure on the needle. To establish an optimal strategy to correct for breast motion due to breathing experiments with a volunteer were performed. Tracking a single centre marker was found to be most effective to improve registration accuracy. Average deviations of 8.2 mm were reduced to 1.1 mm. The combined impact of these different uncertainties resulted in distributions defined by: μ = 2.5 mm, σ = 1.4 mm (benign and malignant), μ = 3.1 mm, σ = 1.8 mm (benign), μ = 1.7 mm, σ = 0.9 mm (malignant).

Real-time 3D ultrasound guidance of autonomous surgical robot for shrapnel detection and breast biopsy

NASA Astrophysics Data System (ADS)

Rogers, Albert J.; Light, Edward D.; von Allmen, Daniel; Smith, Stephen W.

2009-02-01

Two studies have been conducted using real time 3D ultrasound and an automated robot system for carrying out surgical tasks. The first task is to perform a breast lesion biopsy automatically after detection by ultrasound. Combining 3D ultrasound with traditional mammography allows real time guidance of the biopsy needle. Image processing techniques analyze volumes to calculate the location of a target lesion. This position was converted into the coordinate system of a three axis robot which moved a needle probe to touch the lesion. The second task is to remove shrapnel from a tissue phantom autonomously. In some emergency situations, shrapnel detection in the body is necessary for quick treatment. Furthermore, small or uneven shrapnel geometry may hinder location by typical ultrasound imaging methods. Vibrations and small displacements can be induced in ferromagnetic shrapnel by a variable electromagnet. We used real time 3D color Doppler to locate this motion for 2 mm long needle fragments and determined the 3D position of the fragment in the scanner coordinates. The rms error of the image guided robot for 5 trials was 1.06 mm for this task which was accomplished in 76 seconds.

Hollow agarose microneedle with silver coating for intradermal surface-enhanced Raman measurements: a skin-mimicking phantom study

NASA Astrophysics Data System (ADS)

Yuen, Clement; Liu, Quan

2015-06-01

Human intradermal components contain important clinical information beneficial to the field of immunology and disease diagnosis. Although microneedles have shown great potential to act as probes to break the human skin barrier for the minimally invasive measurement of intradermal components, metal microneedles that include stainless steel could cause the following problems: (1) sharp waste production, and (2) contamination due to reuse of microneedles especially in developing regions. In this study, we fabricate agarose microneedles coated with a layer of silver (Ag) and demonstrate their use as a probe for the realization of intradermal surface-enhanced Raman scattering measurements in a set of skin-mimicking phantoms. The Ag-coated agarose microneedle quantifies a range of glucose concentrations from 5 to 150 mM inside the skin phantoms with a root-mean-square error of 5.1 mM within 10 s. The needle is found enlarged by 53.9% after another 6 min inside the phantom. The shape-changing capability of this agarose microneedle ensures that the reuse of these microneedles is impossible, thus avoiding sharp waste production and preventing needle contamination, which shows the great potential for safe and effective needle-based measurements.

Splash: a software tool for stereotactic planning of recording chamber placement and electrode trajectories.

PubMed

Sperka, Daniel J; Ditterich, Jochen

2011-01-01

While computer-aided planning of human neurosurgeries is becoming more and more common, animal researchers still largely rely on paper atlases for planning their approach before implanting recording chambers to perform invasive recordings of neural activity, which makes this planning process tedious and error-prone. Here we present SPLASh (Stereotactic PLAnning Software), an interactive software tool for the stereotactic planning of recording chamber placement and electrode trajectories. SPLASh has been developed for monkey cortical recordings and relies on a combination of structural MRIs and electronic brain atlases. Since SPLASh is based on the neuroanatomy software Caret, it should also be possible to use it for other parts of the brain or other species for which Caret atlases are available. The tool allows the user to interactively evaluate different possible placements of recording chambers and to simulate electrode trajectories.

Splash: A Software Tool for Stereotactic Planning of Recording Chamber Placement and Electrode Trajectories

PubMed Central

Sperka, Daniel J.; Ditterich, Jochen

2011-01-01

While computer-aided planning of human neurosurgeries is becoming more and more common, animal researchers still largely rely on paper atlases for planning their approach before implanting recording chambers to perform invasive recordings of neural activity, which makes this planning process tedious and error-prone. Here we present SPLASh (Stereotactic PLAnning Software), an interactive software tool for the stereotactic planning of recording chamber placement and electrode trajectories. SPLASh has been developed for monkey cortical recordings and relies on a combination of structural MRIs and electronic brain atlases. Since SPLASh is based on the neuroanatomy software Caret, it should also be possible to use it for other parts of the brain or other species for which Caret atlases are available. The tool allows the user to interactively evaluate different possible placements of recording chambers and to simulate electrode trajectories. PMID:21472085

MO-FG-BRA-06: Electromagnetic Beacon Insertion in Lung Cancer Patients and Resultant Surrogacy Errors for Dynamic MLC Tumour Tracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardcastle, N; Booth, J; Caillet, V

Purpose: To assess endo-bronchial electromagnetic beacon insertion and to quantify the geometric accuracy of using beacons as a surrogate for tumour motion in real-time multileaf collimator (MLC) tracking of lung tumours. Methods: The LIGHT SABR trial is a world-first clinical trial in which the MLC leaves move with lung tumours in real time on a standard linear accelerator. Tracking is performed based on implanted electromagnetic beacons (CalypsoTM, Varian Medical Systems, USA) as a surrogate for tumour motion. Five patients have been treated and have each had three beacons implanted endo-bronchially under fluoroscopic guidance. The centre of mass (C.O.M) has beenmore » used to adapt the MLC in real-time. The geometric error in using the beacon C.O.M as a surrogate for tumour motion was measured by measuring the tumour and beacon C.O.M in all phases of the respiratory cycle of a 4DCT. The surrogacy error was defined as the difference in beacon and tumour C.O.M relative to the reference phase (maximum exhale). Results: All five patients have had three beacons successfully implanted with no migration between simulation and end of treatment. Beacon placement relative to tumour C.O.M varied from 14 to 74 mm and in one patient spanned two lobes. Surrogacy error was measured in each patient on the simulation 4DCT and ranged from 0 to 3 mm. Surrogacy error as measured on 4DCT was subject to artefacts in mid-ventilation phases. Surrogacy error was a function of breathing phase and was typically larger at maximum inhale. Conclusion: Beacon placement and thus surrogacy error is a major component of geometric uncertainty in MLC tracking of lung tumours. Surrogacy error must be measured on each patient and incorporated into margin calculation. Reduction of surrogacy error is limited by airway anatomy, however should be taken into consideration when performing beacon insertion and planning. This research is funded by Varian Medical Systems via a collaborative research agreement.« less

Risk behaviours for organism transmission in health care delivery-A two month unstructured observational study.

PubMed

Lindberg, Maria; Lindberg, Magnus; Skytt, Bernice

2017-05-01

Errors in infection control practices risk patient safety. The probability for errors can increase when care practices become more multifaceted. It is therefore fundamental to track risk behaviours and potential errors in various care situations. The aim of this study was to describe care situations involving risk behaviours for organism transmission that could lead to subsequent healthcare-associated infections. Unstructured nonparticipant observations were performed at three medical wards. Healthcare personnel (n=27) were shadowed, in total 39h, on randomly selected weekdays between 7:30 am and 12 noon. Content analysis was used to inductively categorize activities into tasks and based on the character into groups. Risk behaviours for organism transmission were deductively classified into types of errors. Multiple response crosstabs procedure was used to visualize the number and proportion of errors in tasks. One-Way ANOVA with Bonferroni post Hoc test was used to determine differences among the three groups of activities. The qualitative findings gives an understanding of that risk behaviours for organism transmission goes beyond the five moments of hand hygiene and also includes the handling and placement of materials and equipment. The tasks with the highest percentage of errors were; 'personal hygiene', 'elimination' and 'dressing/wound care'. The most common types of errors in all identified tasks were; 'hand disinfection', 'glove usage', and 'placement of materials'. Significantly more errors (p<0.0001) were observed the more multifaceted (single, combined or interrupted) the activity was. The numbers and types of errors as well as the character of activities performed in care situations described in this study confirm the need to improve current infection control practices. It is fundamental that healthcare personnel practice good hand hygiene however effective preventive hygiene is complex in healthcare activities due to the multifaceted care situations, especially when activities are interrupted. A deeper understanding of infection control practices that goes beyond the sense of security by means of hand disinfection and use of gloves is needed as materials and surfaces in the care environment might be contaminated and thus pose a risk for organism transmission. Copyright © 2017 Elsevier Ltd. All rights reserved.

Speech therapy for errors secondary to cleft palate and velopharyngeal dysfunction.

PubMed

Kummer, Ann W

2011-05-01

Individuals with a history of cleft lip/palate or velopharyngeal dysfunction may demonstrate any combination of speech sound errors, hypernasality, and nasal emission. Speech sound distortion can also occur due to other structural anomalies, including malocclusion. Whenever there are structural anomalies, speech can be affected by obligatory distortions or compensatory errors. Obligatory distortions (including hypernasality due to velopharyngeal insufficiency) are caused by abnormal structure and not by abnormal function. Therefore, surgery or other forms of physical management are needed for correction. In contrast, speech therapy is indicated for compensatory articulation productions where articulation placement is changed in response to the abnormal structure. Speech therapy is much more effective if it is done after normalization of the structure. When speech therapy is appropriate, the techniques involve methods to change articulation placement using standard articulation therapy principles. Oral-motor exercises, including the use of blowing and sucking, are never indicated to improve velopharyngeal function. The purpose of this article is to provide information regarding when speech therapy is appropriate for individuals with a history of cleft palate or other structural anomalies and when physical management is needed. In addition, some specific therapy techniques are offered for the elimination of common compensatory articulation productions. © Thieme Medical Publishers.

Generation of Higher Order Modes in a Rectangular Duct

NASA Technical Reports Server (NTRS)

Gerhold, Carl H.; Cabell, Randolph H.; Brown, Donald E.

2004-01-01

Advanced noise control methodologies to reduce sound emission from aircraft engines take advantage of the modal structure of the noise in the duct. This noise is caused by the interaction of rotor wakes with downstream obstructions such as exit guide vanes. Mode synthesis has been accomplished in circular ducts and current active noise control work has made use of this capability to cancel fan noise. The goal of the current effort is to examine the fundamental process of higher order mode propagation through an acoustically treated, curved duct. The duct cross-section is rectangular to permit greater flexibility in representation of a range of duct curvatures. The work presented is the development of a feedforward control system to generate a user-specified modal pattern in the duct. The multiple-error, filtered-x LMS algorithm is used to determine the magnitude and phase of signal input to the loudspeakers to produce a desired modal pattern at a set of error microphones. Implementation issues, including loudspeaker placement and error microphone placement, are discussed. Preliminary results from a 9-3/8 inch by 21 inch duct, using 12 loudspeakers and 24 microphones, are presented. These results demonstrate the ability of the control system to generate a user-specified mode while suppressing undesired modes.

Bench-Top Feasibility Testing of a Novel Percutaneous Renal Access Technique: The Laser Direct Alignment Radiation Reduction Technique (DARRT).

PubMed

Khater, Nazih; Shen, Jim; Arenas, Javier; Keheila, Mohamed; Alsyouf, Muhannad; Martin, Jacob A; Lightfoot, Michelle A; Li, Roger; Olgin, Gaudencio; Smith, Jason C; Baldwin, D Duane

2016-11-01

Traditional techniques for obtaining percutaneous renal access utilize continuous fluoroscopy. In an attempt to minimize radiation exposure, we describe a novel laser direct alignment radiation reduction technique (DARRT) for percutaneous access and test it in a bench-top model. In this randomized-controlled bench-top study, 20 medical personnel obtained renal accesses using both the conventional bullseye technique and the laser DARRT. The primary endpoint was total fluoroscopy time. Secondary endpoints included insertion time, puncture attempts, course corrections, and subjective procedural difficulty. In the laser DARRT, fluoroscopy was used with the C-arm positioned with the laser beam at a 30° angle. The access needle and hub were aligned with the laser beam. Effective caliceal puncture was confirmed with fluoroscopy and direct vision. The Paired samples Wilcoxon signed rank test was used for statistical analysis with significance at p < 0.05. A total of 120 needle placements were recorded. Fluoroscopy time for needle access using the laser DARRT was significantly lower than the bullseye technique in all groups as follows: attendings (7.09 vs 18.51 seconds; p < 0.001), residents (6.55 vs 13.93 seconds; p = 0.001), and medical students (6.69 vs 20.22 seconds; p < 0.001). Students rated the laser DARRT easier to use (2.56 vs 4.89; p < 0.001). No difference was seen in total access time, puncture attempts, or course corrections between techniques. The laser DARRT reduced fluoroscopy time by 63%, compared with the conventional bullseye technique. The least experienced users found the laser DARRT significantly easier to learn. This novel technique is promising and merits additional testing in animal and human models.

Randomized Controlled Trial of a Special Acupuncture Technique for Pain after Thoracotomy

PubMed Central

Deng, Gary; Rusch, Valerie; Vickers, Andrew; Malhortra, Vivek; Ginex, Pamela; Downey, Robert; Bains, Manjit; Park, Bernard; Rizk, Nabil; Flores, Raja; Yeung, Simon; Cassileth, Barrie

2009-01-01

Objective To determine whether an acupuncture technique specially developed for a surgical oncology population (intervention) reduces pain or analgesic use after thoracotomy compared to a sham acupuncture technique (control). Methods One hundred and sixty two cancer patients undergoing thoracotomy were randomized to group A) preoperative implantation of small intradermal needles which were retained for 4 weeks or B) preoperative placement of sham needles at the same schedule. Numerical Rating Scale (NRS) of pain and total opioid use we evaluated during the in-patient stay; Brief Pain Inventory (BPI) and Medication Quantification Scale (MQS) were evaluated after discharge up to 3 months after the surgery. Results The principal analysis, a comparison of BPI pain intensity scores at the 30 day follow-up, showed no significant difference between the intervention and control group. Pain scores were marginally higher in the intervention group 0.05 (95% C.I.: 0.74, -0.64; p=0.9). There were also no statistically significant differences between groups for secondary endpoints, including chronic pain assessments at 60 and 90 days, in-patient pain, and medication use in hospital and after discharge. Conclusion A special acupuncture technique as provided in this study did not reduce pain or use of pain medication after thoracotomy more than a sham technique. PMID:19114190

Clinical and pathological outcomes after irreversible electroporation of the pancreas using two parallel plate electrodes: a porcine model.

PubMed

Rombouts, Steffi J E; van Dijck, Willemijn P M; Nijkamp, Maarten W; Derksen, Tyche C; Brosens, Lodewijk A A; Hoogwater, Frederik J H; van Leeuwen, Maarten S; Borel Rinkes, Inne H M; van Hillegersberg, Richard; Wittkampf, Fred H; Molenaar, Izaak Q

2017-12-01

Irreversible electroporation (IRE) by inserting needles around the tumor as treatment for locally advanced pancreatic cancer entails several disadvantages, such as incomplete ablation due to field inhomogeneity, technical difficulties in needle placement and a risk of pancreatic fistula development. This experimental study evaluates outcomes of IRE using paddles in a porcine model. Six healthy pigs underwent laparotomy and were treated with 2 separate ablations (in head and tail of the pancreas). Follow-up consisted of clinical and laboratory parameters and contrast-enhanced computed tomography (ceCT) imaging. After 2 weeks, pancreatoduodenectomy was performed for histology and the pigs were terminated. All animals survived 14 days. None of the animals developed signs of infection or significant abdominal distention. Serum amylase and lipase peaked at day 1 postoperatively in all pigs, but normalized without signs of pancreatitis. On ceCT-imaging the ablation zone was visible as an ill-defined, hypodense lesion. No abscesses, cysts or ascites were seen. Histology showed a homogenous fibrotic lesion in all pigs. IRE ablation of healthy porcine pancreatic tissue using two plate electrodes is feasible and safe and creates a homogeneous fibrotic lesion. IRE-paddles should be tested on pancreatic adenocarcinoma to determine the effect in cancer tissue. Copyright © 2017. Published by Elsevier Ltd.

Combined ultrasound and fluoroscopic guidance for radiofrequency ablation of the obturator nerve for intractable cancer-associated hip pain.

PubMed

Stone, Jonathan; Matchett, Gerald

2014-01-01

Management of pain from skeletal metastases is notoriously difficult. Case reports and case series have described radiofrequency ablation of the obturator nerve branches to the femoral head for treatment of intractable hip pain. Ablation of the obturator branches to the femoral head is technically difficult because of bony and vascular anatomy, including close proximity of the femoral vessels. Here we present the case of a 79-year-old woman with intractable right hip pain and inability to ambulate secondary to metastatic non-small cell lung cancer in the femoral head and acetabulum, treated with thermal radiofrequency ablation of the obturator and femoral nerve branches to the femoral head. Ablation of the obturator nerve was done via anterior placement of the radiofrequency needle under combined ultrasound and fluoroscopic guidance, passing the radiofrequency needle between the femoral artery and femoral vein. Real-time ultrasound guidance was used to avoid vascular puncture. Thermal radiofrequency ablation resulted in sustained pain relief, and resumption in the ability of the patient to ambulate. From this case we suggest that an anterior approach to the obturator nerve branches to the femoral head may be technically feasible using combined ultrasound and fluoroscopic guidance to avoid vascular puncture.

Stereotactic mammography imaging combined with 3D US imaging for image guided breast biopsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surry, K. J. M.; Mills, G. R.; Bevan, K.

2007-11-15

Stereotactic X-ray mammography (SM) and ultrasound (US) guidance are both commonly used for breast biopsy. While SM provides three-dimensional (3D) targeting information and US provides real-time guidance, both have limitations. SM is a long and uncomfortable procedure and the US guided procedure is inherently two dimensional (2D), requiring a skilled physician for both safety and accuracy. The authors developed a 3D US-guided biopsy system to be integrated with, and to supplement SM imaging. Their goal is to be able to biopsy a larger percentage of suspicious masses using US, by clarifying ambiguous structures with SM imaging. Features from SM andmore » US guided biopsy were combined, including breast stabilization, a confined needle trajectory, and dual modality imaging. The 3D US guided biopsy system uses a 7.5 MHz breast probe and is mounted on an upright SM machine for preprocedural imaging. Intraprocedural targeting and guidance was achieved with real-time 2D and near real-time 3D US imaging. Postbiopsy 3D US imaging allowed for confirmation that the needle was penetrating the target. The authors evaluated 3D US-guided biopsy accuracy of their system using test phantoms. To use mammographic imaging information, they registered the SM and 3D US coordinate systems. The 3D positions of targets identified in the SM images were determined with a target localization error (TLE) of 0.49 mm. The z component (x-ray tube to image) of the TLE dominated with a TLE{sub z} of 0.47 mm. The SM system was then registered to 3D US, with a fiducial registration error (FRE) and target registration error (TRE) of 0.82 and 0.92 mm, respectively. Analysis of the FRE and TRE components showed that these errors were dominated by inaccuracies in the z component with a FRE{sub z} of 0.76 mm and a TRE{sub z} of 0.85 mm. A stereotactic mammography and 3D US guided breast biopsy system should include breast compression for stability and safety and dual modality imaging for target localization. The system will provide preprocedural x-ray mammography information in the form of SM imaging along with real-time US imaging for needle guidance to a target. 3D US imaging will also be available for targeting, guidance, and biopsy verification immediately postbiopsy.« less

The School-Based Multidisciplinary Team and Nondiscriminatory Assessment.

ERIC Educational Resources Information Center

Pfeiffer, Steven I.

The potential of multidisciplinary teams to control for possible errors in diagnosis, classification, and placement and to provide a vehicle for ensuring effective outcomes of diagnostic practices is illustrated. The present functions of the school-based multidisciplinary team (also called, for example, assessment team, child study team, placement…

Multi-rater Agreement in the Assessment of Anterior Cruciate Ligament Reconstruction Failure. A Radiographic and Video Analysis of the MARS Cohort

PubMed Central

Matava, Matthew J.; Arciero, Robert A.; Baumgarten, Keith M.; Carey, James L.; DeBerardino, Thomas M.; Hame, Sharon L.; Hannafin, Jo A.; Miller, Bruce S.; Nissen, Carl W.; Taft, Timothy N.; Wolf, Brian R.; Wright, Rick W.

2015-01-01

Background ACL reconstruction failure occurs in up to 10% of cases. Technical errors are considered the most common cause of graft failure despite the absence of validated studies. There is limited data regarding the agreement among orthopedic surgeons in terms of the etiology of primary ACL reconstruction failure and accuracy of graft tunnel placement. Purpose The purpose of this study is to test the hypothesis that experienced knee surgeons have a high level of inter-observer reliability in the agreement of the etiology of the primary ACL reconstruction failure, anatomical graft characteristics, tunnel placement. Methods Twenty cases of revision ACL reconstruction were randomly selected from the MARS database. Each case included the patient's history, standardized radiographs, and a concise 30-second arthroscopic video taken at the time of revision demonstrating the graft remnant and location of the tunnel apertures. 10 MARS surgeons not involved with the primary surgery reviewed all 20 cases. Each surgeon completed a two-part questionnaire dealing with each surgeon's training and practice as well as the placement of the femoral and tibial tunnels, condition of the primary graft, and the surgeon's opinion as to the etiology of graft failure. Inter-rater agreement was determined for each question. Inter-rater agreement was determined for each question with the kappa coefficient and prevalence adjusted bias adjusted kappa (PABAK). Results The 10 reviewers were in practice an average of 14 years. All performed at least 25 ACL reconstructions per year and 9 were fellowship-trained in sports medicine. There was wide variability in agreement among knee experts as to the specific etiology of ACL graft failure. When specifically asked about technical error as the cause for failure, inter-observer agreement was only slight (prevalence adjusted bias adjusted kappa [PABAK]: 0.26). There was fair overall agreement on ideal femoral tunnel placement (PABAK: 0.55), but only slight agreement whether a femoral tunnel was too anterior (PABAK: 0.24) and fair agreement whether it was too vertical (PABAK: 0.46). There was poor overall agreement for ideal tibial tunnel placement (PABAK: 0.17). Conclusion This study suggests that more objective criteria are needed to accurately determine the etiology of primary ACL graft failure as well as the ideal femoral and tibial tunnel placement in patients undergoing revision ACL reconstruction. PMID:25537942

Simulation improves procedural protocol adherence during central venous catheter placement: a randomized-controlled trial

PubMed Central

Peltan, Ithan D.; Shiga, Takashi; Gordon, James A.; Currier, Paul F.

2015-01-01

Background Simulation training may improve proficiency at and reduces complications from central venous catheter (CVC) placement, but the scope of simulation’s effect remains unclear. This randomized controlled trial evaluated the effects of a pragmatic CVC simulation program on procedural protocol adherence, technical skill, and patient outcomes. Methods Internal medicine interns were randomized to standard training for CVC insertion or standard training plus simulation-based mastery training. Standard training involved a lecture, a video-based online module, and instruction by the supervising physician during actual CVC insertions. Intervention-group subjects additionally underwent supervised training on a venous access simulator until they demonstrated procedural competence. Raters evaluated interns’ performance during internal jugular CVC placement on actual patients in the medical intensive care unit. Generalized estimating equations were used to account for outcome clustering within trainees. Results We observed 52 interns place 87 CVCs. Simulation-trained interns exhibited better adherence to prescribed procedural technique than interns who received only standard training (p=0.024). There were no significant differences detected in first-attempt or overall cannulation success rates, mean needle passes, global assessment scores or complication rates. Conclusions Simulation training added to standard training improved protocol adherence during CVC insertion by novice practitioners. This study may have been too small to detect meaningful differences in venous cannulation proficiency and other clinical outcomes, highlighting the difficulty of patient-centered simulation research in settings where poor outcomes are rare. For high-performing systems, where protocol deviations may provide an important proxy for rare procedural complications, simulation may improve CVC insertion quality and safety. PMID:26154250

Endoscopic ultrasound and endoscopic retrograde cholangiopancreatography for obstructing pancreas head masses: combined or separate procedures?

PubMed

Aslanian, Harry R; Estrada, Juan D; Rossi, Federico; Dziura, James; Jamidar, Priya A; Siddiqui, Uzma D

2011-09-01

Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are complementary procedures in the evaluation of obstructive jaundice. To determine the feasibility, accuracy, and safety of the combined performance of EUS-guided fine needle aspiration (FNA) and ERCP with biliary stenting in patients with obstructive jaundice. Retrospectively reviewed data from consecutive patients presenting with obstructive jaundice due to a pancreas mass at a tertiary referral hospital between April 2002 and November 2007 who underwent combined (under the same sedation and in the same room) or separate EUS and ERCP. Procedure duration, amount of sedative medication administered, ability to achieve biliary stent placement, and the diagnostic yield of EUS-FNA were evaluated. A total of 47 patients were evaluated: 29 patients underwent combined EUS and ERCP and 18 had separate procedures (median of 5 d between procedures). Stent placement at ERCP was successful in 72% combined procedures versus 88% separate ERCP. EUS-FNA diagnosis of malignancy was positive in 91.6% combined versus 87.5% separate. The only complication was self-limited melena after a combined procedure in 1 patient. The median time for combined procedures was 75 minutes versus 50 minutes for separate EUS and 50 minutes for ERCP. Combined EUS and ERCP can be performed under the same sedation with a median 25 minute greater procedure length and similarly high yields for diagnostic EUS-FNA. A nonsignificant trend toward lower biliary stent placement success rates with combined ERCP procedures merits further study. Benefits of a combined procedure may include expedited patient evaluation and the avoidance of repeated sedation.

Pleural space infections after image-guided percutaneous drainage of infected intraabdominal fluid collections: a retrospective single institution analysis.

PubMed

Avella, Diego M; Toth, Jennifer W; Reed, Michael F; Gusani, Niraj J; Kimchi, Eric T; Mahraj, Rickeshvar P; Staveley-O'Carroll, Kevin F; Kaifi, Jussuf T

2015-04-11

Percutaneous drainage of infected intraabdominal fluid collections is preferred over surgical drainage due to lower morbidity and costs. However, it can be a challenging procedure and catheter insertion carries the potential to contaminate the pleural space from the abdomen. This retrospective analysis demonstrates the clinical and radiographic correlation between percutaneous drainage of infected intraabdominal collections and the development of iatrogenic pleural space infections. A retrospective single institution analysis of 550 consecutive percutaneous drainage procedures for intraabdominal fluid collections was performed over 24 months. Patient charts and imaging were reviewed with regard to pleural space infections that were attributed to percutaneous drain placements. Institutional review board approval was obtained for conduct of the study. 6/550 (1.1%) patients developed iatrogenic pleural space infections after percutaneous drainage of intraabdominal fluid collections. All 6 patients presented with respiratory symptoms and required pleural space drainage (either by needle aspiration or chest tube placement), 2 received intrapleural fibrinolytic therapy and 1 patient had to undergo surgical drainage. Pleural effusion cultures revealed same bacteria in both intraabdominal and pleural fluid in 3 (50%) cases. A video with a dynamic radiographic sequence demonstrating the contamination of the pleural space from percutaneous drainage of an infected intraabdominal collection is included. Iatrogenic pleural space infections after percutaneous drainage of intraabdominal fluid collections occur at a low incidence, but the pleural empyema can be progressive requiring prompt chest tube drainage, intrapleural fibrinolytic therapy or even surgery. Expertise in intraabdominal drain placements, awareness and early recognition of this complication is critical to minimize incidence, morbidity and mortality in these patients.

Design and simulation of sensor networks for tracking Wifi users in outdoor urban environments

NASA Astrophysics Data System (ADS)

Thron, Christopher; Tran, Khoi; Smith, Douglas; Benincasa, Daniel

2017-05-01

We present a proof-of-concept investigation into the use of sensor networks for tracking of WiFi users in outdoor urban environments. Sensors are fixed, and are capable of measuring signal power from users' WiFi devices. We derive a maximum likelihood estimate for user location based on instantaneous sensor power measurements. The algorithm takes into account the effects of power control, and is self-calibrating in that the signal power model used by the location algorithm is adjusted and improved as part of the operation of the network. Simulation results to verify the system's performance are presented. The simulation scenario is based on a 1.5 km2 area of lower Manhattan, The self-calibration mechanism was verified for initial rms (root mean square) errors of up to 12 dB in the channel power estimates: rms errors were reduced by over 60% in 300 track-hours, in systems with limited power control. Under typical operating conditions with (without) power control, location rms errors are about 8.5 (5) meters with 90% accuracy within 9 (13) meters, for both pedestrian and vehicular users. The distance error distributions for smaller distances (<30 m) are well-approximated by an exponential distribution, while the distributions for large distance errors have fat tails. The issue of optimal sensor placement in the sensor network is also addressed. We specify a linear programming algorithm for determining sensor placement for networks with reduced number of sensors. In our test case, the algorithm produces a network with 18.5% fewer sensors with comparable accuracy estimation performance. Finally, we discuss future research directions for improving the accuracy and capabilities of sensor network systems in urban environments.

Numerical simulations to assess the tracer dilution method for measurement of landfill methane emissions.

PubMed

Taylor, Diane M; Chow, Fotini K; Delkash, Madjid; Imhoff, Paul T

2016-10-01

Landfills are a significant contributor to anthropogenic methane emissions, but measuring these emissions can be challenging. This work uses numerical simulations to assess the accuracy of the tracer dilution method, which is used to estimate landfill emissions. Atmospheric dispersion simulations with the Weather Research and Forecast model (WRF) are run over Sandtown Landfill in Delaware, USA, using observation data to validate the meteorological model output. A steady landfill methane emissions rate is used in the model, and methane and tracer gas concentrations are collected along various transects downwind from the landfill for use in the tracer dilution method. The calculated methane emissions are compared to the methane emissions rate used in the model to find the percent error of the tracer dilution method for each simulation. The roles of different factors are examined: measurement distance from the landfill, transect angle relative to the wind direction, speed of the transect vehicle, tracer placement relative to the hot spot of methane emissions, complexity of topography, and wind direction. Results show that percent error generally decreases with distance from the landfill, where the tracer and methane plumes become well mixed. Tracer placement has the largest effect on percent error, and topography and wind direction both have significant effects, with measurement errors ranging from -12% to 42% over all simulations. Transect angle and transect speed have small to negligible effects on the accuracy of the tracer dilution method. These tracer dilution method simulations provide insight into measurement errors that might occur in the field, enhance understanding of the method's limitations, and aid interpretation of field data. Copyright © 2016 Elsevier Ltd. All rights reserved.

Colorimetric carbon dioxide detector to determine accidental tracheal feeding tube placement.

PubMed

Howes, Daniel W; Shelley, Eric S; Pickett, William

2005-04-01

To determine the accuracy of colorimetric CO2 detection compared to the reference standard two-step radiological confirmation of feeding tube position. A prospective study was conducted with patients presenting to a 21-bed medical-surgical intensive care unit. An adapter was developed using an endotracheal tube adapter to connect a colorimetric CO2 detector to a feeding tube in an airtight manner. In part I of the study a feeding tube connected to the colorimeter was inserted into the endotracheal tubes of ten ventilated patients to test the device's ability to detect tracheal placement. In part II patients undergoing feeding tube insertion had tube position confirmed with the colorimeter as well as the reference standard two-step x-ray. In phase I the colorimeter correctly identified tracheal placement in all ten patients. In phase II 93/100 procedures ultimately were eligible; the colorimeter had a sensitivity of 0.88 (95% confidence interval: 0.65-1.00) and specificity of 0.99 (0.97-1.00). The device missed one of the eight tracheal placements. Agreement between the colorimeter and two-step x-ray interpretations was excellent (Kappa 0.86; standard error 0.10). We describe a novel, convenient method to confirm esophageal feeding tube placement. The device is easily assembled and inexpensive, but should not be reused. Colorimetric determination of tracheal feeding tube placement with this device has excellent agreement with the reference standard two-step radiological technique.

Epidural steroids for treating "failed back surgery syndrome": is fluoroscopy really necessary?

PubMed

Fredman, B; Nun, M B; Zohar, E; Iraqi, G; Shapiro, M; Gepstein, R; Jedeikin, R

1999-02-01

Epidural steroids are commonly administered in the treatment of "failed back surgery syndrome." Because patient response is dependent on accurate steroid placement, fluoroscopic guidance has been advocated. However, because of ever-increasing medical expenditures, the cost-benefit of routine fluoroscopy should be critically evaluated. Therefore, 50 patients were enrolled into this institutional review board-approved, prospective, controlled, single-blinded study. At a predetermined intervertebral level, the epidural space was identified using an air loss of resistance technique. Thereafter, an epidural catheter was inserted 2 cm through the epidural needle. To determine the accuracy of the clinical placement, contrast medium was administered through the epidural catheter; antero-posterior and lateral lumbar spine radiographs were then obtained. The number of attempts required to successfully locate the epidural space, the reliability of the air loss of resistance technique in indicating successful epidural penetration in failed back surgery syndrome, the ability of the clinician to accurately predict the intervertebral space at which the epidural injection was performed, and the spread of contrast medium within the epidural space were recorded. A total of 48 epidurograms were performed. The number of attempts to successfully enter the epidural space was 2 +/- 1. In 44 cases, the radiological studies confirmed the clinical impression that the epidural space had been successfully identified. In three patients, the epidural catheter was in the paravertebral tissue. One myelogram was recorded. In 25 patients, the epidural catheter did not pass through the predetermined intervertebral space. In 35 cases, the contrast medium did not reach the level of pathology. The clinical sign of loss of resistance is a reliable indicator of epidural space penetration in most cases of "failed back surgery syndrome." However, surface anatomy is unreliable and may result in inaccurate steroid placement. Finally, despite accurate placement, the depot-steroid solution will spread to reach the level of pathology in only 26% of cases.

Strategic Use of Microscrews for Enhancing the Accuracy of Computer-Guided Implant Surgery in Fully Edentulous Arches: A Case History Report.

PubMed

Lee, Du-Hyeong

Implant guide systems can be classified by their supporting structure as tooth-, mucosa-, or bone-supported. Mucosa-supported guides for fully edentulous arches show lower accuracy in implant placement because of errors in image registration and guide positioning. This article introduces the application of a novel microscrew system for computer-aided implant surgery. This technique can markedly improve the accuracy of computer-guided implant surgery in fully edentulous arches by eliminating errors from image fusion and guide positioning.

Autonomous surgical robotics using 3-D ultrasound guidance: feasibility study.

PubMed

Whitman, John; Fronheiser, Matthew P; Ivancevich, Nikolas M; Smith, Stephen W

2007-10-01

The goal of this study was to test the feasibility of using a real-time 3D (RT3D) ultrasound scanner with a transthoracic matrix array transducer probe to guide an autonomous surgical robot. Employing a fiducial alignment mark on the transducer to orient the robot's frame of reference and using simple thresholding algorithms to segment the 3D images, we tested the accuracy of using the scanner to automatically direct a robot arm that touched two needle tips together within a water tank. RMS measurement error was 3.8% or 1.58 mm for an average path length of 41 mm. Using these same techniques, the autonomous robot also performed simulated needle biopsies of a cyst-like lesion in a tissue phantom. This feasibility study shows the potential for 3D ultrasound guidance of an autonomous surgical robot for simple interventional tasks, including lesion biopsy and foreign body removal.

Hamstring Graft Preparation Using a Modified Rolling Hitch Technique

PubMed Central

Hong, Chih-Kai; Chang, Chih-Hsun; Chiang, Chen-Hao; Jou, I-Ming; Su, Wei-Ren

2014-01-01

Anterior cruciate ligament reconstruction using double-looped hamstring autograft is a common procedure in orthopaedic practice. However, during placement of the running, locking stitches at each end of the harvested tendons, the surgeon may face several potential obstacles, including the risk of damaging the tendon, predisposing the surgeon to needle-stick injury, and extended time consumption. We report a modified rolling hitch technique for hamstring graft preparation that is quick, cost-saving, and needleless as an alternative method. The original rolling hitch technique uses a traditional knot that attaches a rope to an object; the modified rolling hitch technique was created by adding 1 more turn before finishing with a half-hitch, which may prevent suture slippage off the tendon, thus providing sufficient fixation of the suture-tendon construct. PMID:25126495

A case of stapler pin in the root canal--extending beyond the apex.

PubMed

Rao, A; Sudha, P

1999-01-01

There have been several reports describing the placement, by patients, of foreign objects into exposed pulp chambers and canals. In the present case, a 13-year-old patient reported with complaints of pain and a history of inserting a foreign object into the root canal of the left central incisor. On examination the foreign body was found to be a stapler pin which was projecting 5 millimeters from the apical foramen. Foreign bodies discovered from the root canal have varied from radiolucent objects like wooden tooth picks or tooth brush bristles to radioopaque materials like paper pins, needles, pencil leads etc. In the present case, despite our best efforts, the patient did not agree to undergo any treatment except for the extraction of the left central incisor.

Treatment Planning and Image Guidance for Radiofrequency Ablations of Large Tumors

PubMed Central

Ren, Hongliang; Campos-Nanez, Enrique; Yaniv, Ziv; Banovac, Filip; Abeledo, Hernan; Hata, Nobuhiko; Cleary, Kevin

2014-01-01

This article addresses the two key challenges in computer-assisted percutaneous tumor ablation: planning multiple overlapping ablations for large tumors while avoiding critical structures, and executing the prescribed plan. Towards semi-automatic treatment planning for image-guided surgical interventions, we develop a systematic approach to the needle-based ablation placement task, ranging from pre-operative planning algorithms to an intra-operative execution platform. The planning system incorporates clinical constraints on ablations and trajectories using a multiple objective optimization formulation, which consists of optimal path selection and ablation coverage optimization based on integer programming. The system implementation is presented and validated in phantom studies and on an animal model. The presented system can potentially be further extended for other ablation techniques such as cryotherapy. PMID:24235279

Laser and radiofrequency-induced hyperthermia treatment via gold-coated magnetic nanocomposites

PubMed Central

Elsherbini, Alsayed AM; Saber, Mahmoud; Aggag, Mohamed; El-Shahawy, Ahmed; Shokier, Hesham AA

2011-01-01

Introduction The current radiofrequency ablation technique requires invasive needle placement. On the other hand, most of the common photothermal therapeutic methods are limited by lack of accuracy of targeting. Gold and magnetic nanoparticles offer the potential to heat tumor tissue selectively at the cellular level by noninvasive interaction with laser and radiofrequency. Methods Gold nanospheres and gold-coated magnetic nanocomposites were used for inducing hyperthermia to treat subcutaneous Ehrlich carcinoma implanted in female mice. Results In mice treated with gold nanospheres, tumors continued to grow but at a slow rate. In contrast, more than 50% of the tumors treated with gold-coated magnetic nanocomposites completely disappeared. Conclusion This simple and noninvasive method shows great promise as a technique for selective magnetic photothermal treatment. PMID:22114479

Optimal sensor placement for spatial lattice structure based on genetic algorithms

NASA Astrophysics Data System (ADS)

Liu, Wei; Gao, Wei-cheng; Sun, Yi; Xu, Min-jian

2008-10-01

Optimal sensor placement technique plays a key role in structural health monitoring of spatial lattice structures. This paper considers the problem of locating sensors on a spatial lattice structure with the aim of maximizing the data information so that structural dynamic behavior can be fully characterized. Based on the criterion of optimal sensor placement for modal test, an improved genetic algorithm is introduced to find the optimal placement of sensors. The modal strain energy (MSE) and the modal assurance criterion (MAC) have been taken as the fitness function, respectively, so that three placement designs were produced. The decimal two-dimension array coding method instead of binary coding method is proposed to code the solution. Forced mutation operator is introduced when the identical genes appear via the crossover procedure. A computational simulation of a 12-bay plain truss model has been implemented to demonstrate the feasibility of the three optimal algorithms above. The obtained optimal sensor placements using the improved genetic algorithm are compared with those gained by exiting genetic algorithm using the binary coding method. Further the comparison criterion based on the mean square error between the finite element method (FEM) mode shapes and the Guyan expansion mode shapes identified by data-driven stochastic subspace identification (SSI-DATA) method are employed to demonstrate the advantage of the different fitness function. The results showed that some innovations in genetic algorithm proposed in this paper can enlarge the genes storage and improve the convergence of the algorithm. More importantly, the three optimal sensor placement methods can all provide the reliable results and identify the vibration characteristics of the 12-bay plain truss model accurately.

Comparison of Deep Brain Stimulation Lead Targeting Accuracy and Procedure Duration between 1.5- and 3-Tesla Interventional Magnetic Resonance Imaging Systems: An Initial 12-Month Experience.

PubMed

Southwell, Derek G; Narvid, Jared A; Martin, Alastair J; Qasim, Salman E; Starr, Philip A; Larson, Paul S

2016-01-01

Interventional magnetic resonance imaging (iMRI) allows deep brain stimulator lead placement under general anesthesia. While the accuracy of lead targeting has been described for iMRI systems utilizing 1.5-tesla magnets, a similar assessment of 3-tesla iMRI procedures has not been performed. To compare targeting accuracy, the number of lead targeting attempts, and surgical duration between procedures performed on 1.5- and 3-tesla iMRI systems. Radial targeting error, the number of targeting attempts, and procedure duration were compared between surgeries performed on 1.5- and 3-tesla iMRI systems (SmartFrame and ClearPoint systems). During the first year of operation of each system, 26 consecutive leads were implanted using the 1.5-tesla system, and 23 consecutive leads were implanted using the 3-tesla system. There was no significant difference in radial error (Mann-Whitney test, p = 0.26), number of lead placements that required multiple targeting attempts (Fisher's exact test, p = 0.59), or bilateral procedure durations between surgeries performed with the two systems (p = 0.15). Accurate DBS lead targeting can be achieved with iMRI systems utilizing either 1.5- or 3-tesla magnets. The use of a 3-tesla magnet, however, offers improved visualization of the target structures and allows comparable accuracy and efficiency of placement at the selected targets. © 2016 S. Karger AG, Basel.

Brain Research: The Necessity for Separating Sites, Actions and Functions.

ERIC Educational Resources Information Center

Meeker, Mary

Educators, as applied scientists, must work in partnership with investigative scientists who are researching brain functions in order to reach a better understanding of gifted students and students who are intelligent but do not learn. Improper understanding of brain functions can cause gross errors in educational placement. Until recently, the…

The AP Descriptive Chemistry Question: Student Errors

ERIC Educational Resources Information Center

Crippen, Kent; Brooks, David W.

2005-01-01

For over a decade, the authors have been involved in a design theory experiment providing software for high school students preparing for the descriptive question on the Advanced Placement (AP) chemistry examination. Since 1997, the software has been available as a Web site offering repeatable practice. This study describes a 4-year project during…

Investigating the Retention and Time Course of Phonotactic Constraint Learning from Production Experience

ERIC Educational Resources Information Center

Warker, Jill A.

2013-01-01

Adults can rapidly learn artificial phonotactic constraints such as /"f"/ "occurs only at the beginning of syllables" by producing syllables that contain those constraints. This implicit learning is then reflected in their speech errors. However, second-order constraints in which the placement of a phoneme depends on another…

Three-dimensional planning and use of patient-specific guides improve glenoid component position: an in vitro study.

PubMed

Walch, Gilles; Vezeridis, Peter S; Boileau, Pascal; Deransart, Pierric; Chaoui, Jean

2015-02-01

Glenoid component positioning is a key factor for success in total shoulder arthroplasty. Three-dimensional (3D) measurements of glenoid retroversion, inclination, and humeral head subluxation are helpful tools for preoperative planning. The purpose of this study was to assess the reliability and precision of a novel surgical method for placing the glenoid component with use of patient-specific templates created by preoperative surgical planning and 3D modeling. A preoperative computed tomography examination of cadaveric scapulae (N = 18) was performed. The glenoid implants were virtually placed, and patient-specific guides were created to direct the guide pin into the desired orientation and position in the glenoid. The 3D orientation and position of the guide pin were evaluated by performing a postoperative computed tomography scan for each scapula. The differences between the preoperative planning and the achieved result were analyzed. The mean error in 3D orientation of the guide pin was 2.39°, the mean entry point position error was 1.05 mm, and the mean inclination angle error was 1.42°. The average error in the version angle was 1.64°. There were no technical difficulties or complications related to use of patient-specific guides for guide pin placement. Quantitative analysis of guide pin positioning demonstrated a good correlation between preoperative planning and the achieved position of the guide pin. This study demonstrates the reliability and precision of preoperative planning software and patient-specific guides for glenoid component placement in total shoulder arthroplasty. Copyright © 2015. Published by Elsevier Inc.

Segmentation via fusion of edge and needle map

NASA Astrophysics Data System (ADS)

Ahn, Hong-Young; Tou, Julius T.

1991-03-01

This paper presents an integrated image segmentation method using edge and needle map which compensates deficiencies of using either edge-based approach or region-based approach. Segmentation of an image is the first and most difficult step toward symbolic transformation of a raw image, which is essential in image understanding. In industrial applications, the task is further complicated by the ubiquitous presence of specularity in most industrial parts. Three images taken from three different illumination directions were used to separate specular and Lambertian components in the images. Needle map is generated from Lambertian component images using photometric stereo technique. In one channel, edges are extracted and linked from the averaged Lambertian images providing one source of segmentation. The other channel, Gaussian curvature and mean curvature values are estimated at each pixel from least square local surface fit of needle map. Labeled surface type image is then generated using the signs of Gaussian and mean curvatures, where one of ten surface types is assigned to each pixel. Connected regions of identical surface type pixels provide the first level grouping, a rough initial segmentation. Edge information and initial segmentation of surface type are fed to an integration module which interprets the edges and regions in a consistent way. During interpretation regions are merged or split, edges are discarded or generated depending upon global surface fit error and consistency with neighboring regions. The output of integrated segmentation is an explicit description of surface type and contours of each region which facilitates recognition, localization and attitude determination of objects in the image.

Ease of intravenous catheterisation in dogs and cats: a comparative study of two peripheral catheters.

PubMed

Chebroux, A; Leece, E A; Brearley, J C

2015-04-01

To evaluate animal comfort and ease of placement of a veterinary-specific intravenous catheter compared with a catheter manufactured for human use. Fifty-nine veterinary undergraduates were recruited to perform intravenous catheterisations with two brands of over-the-needle catheter [Smiths Medical Jelco® (human use) and Abbott Animal Health catheter® (veterinary use)] in 69 healthy cats (n = 28) and dogs (n = 41) requiring general anaesthesia. After a standardised pre-anaesthetic medication, each animal was randomly allocated to have one of the two brands of catheter placed. Each student was allowed a maximum of three attempts to achieve cephalic vein catheterisation. The student and a single experienced observer evaluated each attempt. Observations related to ease of placement and to the animal's reaction were recorded. Human use catheters were placed in 34 and veterinary use in 35 animals. There was no difference in weight, sex or sedation score between the two groups. The number of failed attempts was similar between the two groups. There was no difference between groups for the number of animals reacting to catheter insertion. The two types of catheters evaluated are equally suitable for intravenous catheterisation of sedated animals by veterinary undergraduate students. © 2015 British Small Animal Veterinary Association.

Autonomous Rover Traverse and Precise Arm Placement on Remotely Designated Targets

NASA Technical Reports Server (NTRS)

Felder, Michael; Nesnas, Issa A.; Pivtoraiko, Mihail; Kelly, Alonzo; Volpe, Richard

2011-01-01

Exploring planetary surfaces typically involves traversing challenging and unknown terrain and acquiring in-situ measurements at designated locations using arm-mounted instruments. We present field results for a new implementation of an autonomous capability that enables a rover to traverse and precisely place an arm-mounted instrument on remote targets. Using point-and-click mouse commands, a scientist designates targets in the initial imagery acquired from the rover's mast cameras. The rover then autonomously traverse the rocky terrain for a distance of 10 - 15 m, tracks the target(s) of interest during the traverse, positions itself for approaching the target, and then precisely places an arm-mounted instrument within 2-3 cm from the originally designated target. The rover proceeds to acquire science measurements with the instrument. This work advances what has been previously developed and integrated on the Mars Exploration Rovers by using algorithms that are capable of traversing more rock-dense terrains, enabling tight thread-the-needle maneuvers. We integrated these algorithms on the newly refurbished Athena Mars research rover and fielded them in the JPL Mars Yard. We conducted 43 runs with targets at distances ranging from 5 m to 15 m and achieved a success rate of 93% for placement of the instrument within 2-3 cm.

Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

NASA Technical Reports Server (NTRS)

Bugbee, B.; Monje, O.; Tanner, B.

1996-01-01

Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

Particle contamination effects in EUVL: enhanced theory for the analytical determination of critical particle sizes

NASA Astrophysics Data System (ADS)

Brandstetter, Gerd; Govindjee, Sanjay

2012-03-01

Existing analytical and numerical methodologies are discussed and then extended in order to calculate critical contamination-particle sizes, which will result in deleterious effects during EUVL E-chucking in the face of an error budget on the image-placement-error (IPE). The enhanced analytical models include a gap dependant clamping pressure formulation, the consideration of a general material law for realistic particle crushing and the influence of frictional contact. We present a discussion of the defects of the classical de-coupled modeling approach where particle crushing and mask/chuck indentation are separated from the global computation of mask bending. To repair this defect we present a new analytic approach based on an exact Hankel transform method which allows a fully coupled solution. This will capture the contribution of the mask indentation to the image-placement-error (estimated IPE increase of 20%). A fully coupled finite element model is used to validate the analytical models and to further investigate the impact of a mask back-side CrN-layer. The models are applied to existing experimental data with good agreement. For a standard material combination, a given IPE tolerance of 1 nm and a 15 kPa closing pressure, we derive bounds for single particles of cylindrical shape (radius × height < 44 μm) and spherical shape (diameter < 12 μm).

Evaluation of photomask flatness compensation for extreme ultraviolet lithography

NASA Astrophysics Data System (ADS)

Ballman, Katherine; Lee, Christopher; Zimmerman, John; Dunn, Thomas; Bean, Alexander

2016-10-01

As the semiconductor industry continues to strive towards high volume manufacturing for EUV, flatness specifications for photomasks have decreased to below 10nm for 2018 production, however the current champion masks being produced report P-V flatness values of roughly 50nm. Write compensation presents the promising opportunity to mitigate pattern placement errors through the use of geometrically adjusted target patterns which counteract the reticle's flatness induced distortions and address the differences in chucking mechanisms between e-beam write and electrostatic clamping during scan. Compensation relies on high accuracy flatness data which provides the critical topographical components of the reticle to the write tool. Any errors included in the flatness data file are translated to the pattern during the write process, which has now driven flatness measurement tools to target a 6σ reproducibility <1nm. Using data collected from a 2011 Sematech study on the Alpha Demo Tool, the proposed methodology for write compensation is validated against printed wafer results. Topographic features which lack compensation capability must then be held to stringent specifications in order to limit their contributions to the final image placement error (IPE) at wafer. By understanding the capabilities and limitations of write compensation, it is then possible to shift flatness requirements towards the "non-correctable" portion of the reticle's profile, potentially relieving polishers from having to adhere to the current single digit flatness specifications.

Fine needle aspiration cytology of oral and oropharyngeal lesions with an emphasis on the diagnostic utility and pitfalls.

PubMed

Gupta, Nalini; Banik, Tarak; Rajwanshi, Arvind; Radotra, Bishan D; Panda, Naresh; Dey, Pranab; Srinivasan, Radhika; Nijhawan, Raje

2012-01-01

This study was undertaken to evaluate the diagnostic utility and pitfalls of fine needle aspiration cytology (FNAC) in oral and oropharyngeal lesions. This was a retrospective audit of oral and oropharyngeal lesions diagnosed with FNAC over a period of six years (2005-2010). Oral/oropharyngeal lesions [n=157] comprised 0.35% of the total FNAC load. The age ranged 1-80 years with the male: female ratio being 1.4:1. Aspirates were inadequate in 7% cases. Histopathology was available in 73/157 (46.5%) cases. Palate was the most common site of involvement [n=66] followed by tongue [n=35], buccal mucosa [n=18], floor of the mouth [n=17], tonsil [n=10], alveolus [n=5], retromolar trigone [n=3], and posterior pharyngeal wall [n=3]. Cytodiagnoses were categorized into infective/inflammatory lesions and benign cysts, and benign and malignant tumours. Uncommon lesions included ectopic lingual thyroid and adult rhabdomyoma of tongue, and solitary fibrous tumor (SFT), and leiomyosarcoma in buccal mucosa. A single false-positive case was dense inflammation with squamous cells misinterpreted as squamous cell carcinoma (SCC) on cytology. There were eight false-negative cases mainly due to sampling error. One false-negative case due to interpretation error was in a salivary gland tumor. The sensitivity of FNAC in diagnosing oral/oropharyngeal lesions was 71.4%; specificity was 97.8% with diagnostic accuracy of 87.7%. Salivary gland tumors and squamous cell carcinoma (SCC) are the most common lesions seen in the oral cavity. FNAC proves to be highly effective in diagnosing the spectrum of different lesions in this region. Sampling error is the main cause of false-negative cases in this region.

Greater physician involvement improves coding outcomes in endobronchial ultrasound-guided transbronchial needle aspiration procedures.

PubMed

Pillai, Anilkumar; Medford, Andrew R L

2013-01-01

Correct coding is essential for accurate reimbursement for clinical activity. Published data confirm that significant aberrations in coding occur, leading to considerable financial inaccuracies especially in interventional procedures such as endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Previous data reported a 15% coding error for EBUS-TBNA in a U.K. service. We hypothesised that greater physician involvement with coders would reduce EBUS-TBNA coding errors and financial disparity. The study was done as a prospective cohort study in the tertiary EBUS-TBNA service in Bristol. 165 consecutive patients between October 2009 and March 2012 underwent EBUS-TBNA for evaluation of unexplained mediastinal adenopathy on computed tomography. The chief coder was prospectively electronically informed of all procedures and cross-checked on a prospective database and by Trust Informatics. Cost and coding analysis was performed using the 2010-2011 tariffs. All 165 procedures (100%) were coded correctly as verified by Trust Informatics. This compares favourably with the 14.4% coding inaccuracy rate for EBUS-TBNA in a previous U.K. prospective cohort study [odds ratio 201.1 (1.1-357.5), p = 0.006]. Projected income loss was GBP 40,000 per year in the previous study, compared to a GBP 492,195 income here with no coding-attributable loss in revenue. Greater physician engagement with coders prevents coding errors and financial losses which can be significant especially in interventional specialties. The intervention can be as cheap, quick and simple as a prospective email to the coding team with cross-checks by Trust Informatics and against a procedural database. We suggest that all specialties should engage more with their coders using such a simple intervention to prevent revenue losses. Copyright © 2013 S. Karger AG, Basel.

Sci—Fri PM: Topics — 08: The Role and Benefits of Electromagnetic Needle-Tracking Technologies in Brachytherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beaulieu, L.; Racine, E.; Boutaleb, S.

In modern brachytherapy, application of large doses of ionizing radiation in a limited number of fractions is frequent. Furthermore, as with any surgical procedures, brachytherapy is subject to learning curve effects. In this context, there could be advantages of integrating real-time tracking of needles/catheters to existing protocols given the recent prominent advances in tracking technologies. In this work, we review the use of an electromagnetic tracking system (EMTS) based on the second generation Aurora® Planar Field Generator (Northern Digital Inc) and custom design needles (Philips Healthcare) for brachytherapy applications. The position and orientation information is obtained from 5 degrees ofmore » freedom sensors. Basic system performance characterization is performed in well-controlled conditions to establish accuracy and reproducibility as well as potential interference from standard brachytherapy equipment. The results show that sensor locations can be tracked to within 0.04mm (la) when located within 26cm of the generator. Orientation accuracy of the needle remained within ±1° in the same region, but rose quickly at larger distances. The errors on position and orientation strongly dependent the sensor position in the characterization volume (500×500×500mm{sup 3}). The presence of an ultrasound probe was shown to have negligible effects on tracking accuracy. The use of EMTS for automatic catheter/applicator reconstruction was also explored. Reconstruction time was less than 10 sec/channel and tips identification was within 0.69±0.29mm of the reference values. Finally, we demonstrate that hollow needle designs with special EM adaptation also allow for real-time seed drop position estimation. In phantom experiments showed that drop positions were on average within 1.6±0.9mm of the reference position measured from μCT. Altogether, EMTS offer promising benefits in a wide range of brachytherapy applications.« less

Automatic detection of a hand-held needle in ultrasound via phased-based analysis of the tremor motion

NASA Astrophysics Data System (ADS)

Beigi, Parmida; Salcudean, Septimiu E.; Rohling, Robert; Ng, Gary C.

2016-03-01

This paper presents an automatic localization method for a standard hand-held needle in ultrasound based on temporal motion analysis of spatially decomposed data. Subtle displacement arising from tremor motion has a periodic pattern which is usually imperceptible in the intensity image but may convey information in the phase image. Our method aims to detect such periodic motion of a hand-held needle and distinguish it from intrinsic tissue motion, using a technique inspired by video magnification. Complex steerable pyramids allow specific design of the wavelets' orientations according to the insertion angle as well as the measurement of the local phase. We therefore use steerable pairs of even and odd Gabor wavelets to decompose the ultrasound B-mode sequence into various spatial frequency bands. Variations of the local phase measurements in the spatially decomposed input data is then temporally analyzed using a finite impulse response bandpass filter to detect regions with a tremor motion pattern. Results obtained from different pyramid levels are then combined and thresholded to generate the binary mask input for the Hough transform, which determines an estimate of the direction angle and discards some of the outliers. Polynomial fitting is used at the final stage to remove any remaining outliers and improve the trajectory detection. The detected needle is finally added back to the input sequence as an overlay of a cloud of points. We demonstrate the efficiency of our approach to detect the needle using subtle tremor motion in an agar phantom and in-vivo porcine cases where intrinsic motion is also present. The localization accuracy was calculated by comparing to expert manual segmentation, and presented in (mean, standard deviation and root-mean-square error) of (0.93°, 1.26° and 0.87°) and (1.53 mm, 1.02 mm and 1.82 mm) for the trajectory and the tip, respectively.

Electromagnetic navigation system for CT-guided biopsy of small lesions.

PubMed

Appelbaum, Liat; Sosna, Jacob; Nissenbaum, Yizhak; Benshtein, Alexander; Goldberg, S Nahum

2011-05-01

The purpose of this study was to evaluate an electromagnetic navigation system for CT-guided biopsy of small lesions. Standardized CT anthropomorphic phantoms were biopsied by two attending radiologists. CT scans of the phantom and surface electromagnetic fiducial markers were imported into the memory of the 3D electromagnetic navigation system. Each radiologist assessed the accuracy of biopsy using electromagnetic navigation alone by targeting sets of nine lesions (size range, 8-14 mm; skin to target distance, 5.7-12.8 cm) under eight different conditions of detector field strength and orientation (n = 117). As a control, each radiologist also biopsied two sets of five targets using conventional CT-guided technique. Biopsy accuracy, number of needle passes, procedure time, and radiation dose were compared. Under optimal conditions (phantom perpendicular to the electromagnetic receiver at highest possible field strength), phantom accuracy to the center of the lesion was 2.6 ± 1.1 mm. This translated into hitting 84.4% (38/45) of targets in a single pass (1.1 ± 0.4 CT confirmations), which was significantly fewer than the 3.6 ± 1.3 CT checks required for conventional technique (p < 0.001). The mean targeting time was 38.8 ± 18.2 seconds per lesion. Including procedural planning (∼5.5 minutes) and final CT confirmation of placement (∼3.5 minutes), the full electromagnetic tracking procedure required significantly less time (551.6 ± 87.4 seconds [∼9 minutes]) than conventional CT (833.3 ± 283.8 seconds [∼14 minutes]) for successful targeting (p < 0.001). Less favorable conditions, including nonperpendicular relation between the axis of the machine and weaker field strength, resulted in statistically significant lower accuracy (3.7 ± 1 mm, p < 0.001). Nevertheless, first-pass biopsy accuracy was 58.3% (21/36) and second-pass (35/36) accuracy was 97.2%. Lesions farther from the skin than 20-25 cm were out of range for successful electromagnetic tracking. Virtual electromagnetic tracking appears to have high accuracy in needle placement, potentially reducing time and radiation exposure compared with those of conventional CT techniques in the biopsy of small lesions.

High-Fidelity Simulation: A New Method for Improving Medication Administration Skills of Undergraduate Nursing Students in Jordan

ERIC Educational Resources Information Center

Mohammad, Anas Ahmad Ali

2017-01-01

Although administering medicines is one of the core nursing actions, errors surrounding this task are prevalent amongst nurses and nursing students. Continued dependence on traditional teaching methods and greater demand and competition for clinical placements are some barriers to expanding medication administration practices for nursing students.…

Purposeful creation of a pneumothorax and chest tube placement to facilitate CT-guided coil localization of lung nodules before video-assisted thoracoscopic surgical wedge resection.

PubMed

Iqbal, Shams I; Molgaard, Christopher; Williamson, Christina; Flacke, Sebastian

2014-07-01

To evaluate the feasibility and efficacy of pneumothorax creation and chest tube insertion before computed tomography (CT)-guided coil localization of small peripheral lung nodules for video-assisted thoracoscopic surgical (VATS) wedge resection. From May 2011 to October 2013, 21 consecutive patients (seven men; mean age, 62 y; range, 42-76 y) scheduled for VATS wedge resection required CT-guided coil localization for small, likely nonpalpable peripheral lung lesions at a single institution. Outcomes were evaluated retrospectively for technical success and complications. There were 12 nodules and nine ground-glass opacities. Mean lesion distance from the pleural surface was 15 mm (range, 5-35 mm), and average size was 13 mm (range, 7-30 mm). A pneumothorax was successfully created in all patients with a Veress needle, and a chest tube was inserted. All target lesions were marked successfully, leaving one end of the coil within/beyond the lesion and the other end of the coil in the pleural space. The inserted chest tube was used to insufflate air to widen the pleural space during coil positioning and to aspirate any residual air before transfer of the patient to the operating room holding area. Intraparenchymal hemorrhages smaller than 7 cm in diameter developed in two patients during coil placement. All lesions were successfully resected with VATS. Histologic examinaiton revealed 13 primary adenocarcinomas, four metastases, and four benign lesions. Pneumothorax creation and chest tube placement before CT-guided coil localization of peripheral lung nodules for VATS wedge resection facilitates the deployment of the peripheral end of the coil in the pleural space and provides effective management of procedure-related pneumothorax until surgery. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

Mini access guide to simplify calyceal access during percutaneous nephrolithotomy: A novel device.

PubMed

Chowdhury, Puskar Shyam; Nayak, Prasant; David, Deepak; Mallick, Sujata

2017-01-01

A precise puncture of the renal collecting system is the most essential step for percutaneous nephrolithotomy (PCNL). There are many techniques describing this crucial first step in PCNL including the bull's eye technique, triangulation technique, free-hand technique, and gradual descensus technique. We describe a novel puncture guide to assist accurate percutaneous needle placement during bull's eye technique. The mini access guide (MAG) stabilizes the initial puncture needle by mounting it on an adjustable multidirectional carrier fixed to the patient's skin, which aids in achieving the "bull's eye" puncture. It also avoids a direct fluoroscopic exposure of the urologist's hand during the puncture. Sixty consecutive patients with solitary renal calculus were randomized to traditional hand versus MAG puncture during bull's eye technique of puncture and the fluoroscopy time was assessed. The median fluoroscopy screening time for traditional free-hand bull's eye and MAG-guided bull's eye puncture (fluoroscopic screening time for puncture) was 55 versus 21 s ( P = 0.001) and the median time to puncture was 80 versus 55 s ( P = 0.052), respectively. Novice residents also learned puncture technique faster with MAG on simulator. The MAG is a simple, portable, cheap, and novel assistant to achieve successful PCNL puncture. It would be of great help for novices to establish access during their learning phase of PCNL. It would also be an asset toward significantly decreasing the radiation dose during PCNL access.

Use and accuracy of US guidance for image-guided injections of the temporomandibular joints in children with arthritis.

PubMed

Parra, Dimitri A; Chan, Melissa; Krishnamurthy, Ganesh; Spiegel, Lynn; Amaral, Joao G; Temple, Michael J; John, Philip R; Connolly, Bairbre L

2010-09-01

Juvenile idiopathic arthritis (JIA) has an incidence that ranges from 1 to 22 per 100,000 children worldwide, with involvement of the temporomandibular joint (TMJ) in 17-87% of patients. Intraarticular corticosteroid injections are beneficial in the local treatment of JIA and of other types of arthritis. To describe and assess the accuracy of an US-guided technique for visualization of needle placement within the TMJ in children. Between January 2000 and November 2007, 180 TMJ injections were performed during 116 encounters in 83 children with arthritis (71 girls, 12 boys; mean age 12.0 years). Access was obtained under sterile conditions using US guidance (linear 15-MHz or curvilinear 8-MHz transducers) in a coronal plane, and confirmed with CT. To minimize radiation, a limited focused CT protocol was developed. A bilateral injection was performed in 65 encounters (57%). Twenty-three children had repeat TMJ injections. All injections were performed using US guidance. CT confirmation was used in 127/180 TMJs (70%). In those confirmed with CT, the needle tip was intra-articular in 91% of cases. Triamcinolone hexacetonide was used in 92% of injections and triamcinolone acetonide in 8%. One major complication was encountered (skin atrophy at the injection site). In our experience, TMJ injections using sonographic guidance is a safe, effective and accurate procedure.

A semi-automated vascular access system for preclinical models

NASA Astrophysics Data System (ADS)

Berry-Pusey, B. N.; Chang, Y. C.; Prince, S. W.; Chu, K.; David, J.; Taschereau, R.; Silverman, R. W.; Williams, D.; Ladno, W.; Stout, D.; Tsao, T. C.; Chatziioannou, A.

2013-08-01

Murine models are used extensively in biological and translational research. For many of these studies it is necessary to access the vasculature for the injection of biologically active agents. Among the possible methods for accessing the mouse vasculature, tail vein injections are a routine but critical step for many experimental protocols. To perform successful tail vein injections, a high skill set and experience is required, leaving most scientists ill-suited to perform this task. This can lead to a high variability between injections, which can impact experimental results. To allow more scientists to perform tail vein injections and to decrease the variability between injections, a vascular access system (VAS) that semi-automatically inserts a needle into the tail vein of a mouse was developed. The VAS uses near infrared light, image processing techniques, computer controlled motors, and a pressure feedback system to insert the needle and to validate its proper placement within the vein. The VAS was tested by injecting a commonly used radiolabeled probe (FDG) into the tail veins of five mice. These mice were then imaged using micro-positron emission tomography to measure the percentage of the injected probe remaining in the tail. These studies showed that, on average, the VAS leaves 3.4% of the injected probe in the tail. With these preliminary results, the VAS system demonstrates the potential for improving the accuracy of tail vein injections in mice.

Dialysis Facility Safety: Processes and Opportunities.

PubMed

Garrick, Renee; Morey, Rishikesh

2015-01-01

Unintentional human errors are the source of most safety breaches in complex, high-risk environments. The environment of dialysis care is extremely complex. Dialysis patients have unique and changing physiology, and the processes required for their routine care involve numerous open-ended interfaces between providers and an assortment of technologically advanced equipment. Communication errors, both within the dialysis facility and during care transitions, and lapses in compliance with policies and procedures are frequent areas of safety risk. Some events, such as air emboli and needle dislodgments occur infrequently, but are serious risks. Other adverse events include medication errors, patient falls, catheter and access-related infections, access infiltrations and prolonged bleeding. A robust safety system should evaluate how multiple, sequential errors might align to cause harm. Systems of care can be improved by sharing the results of root cause analyses, and "good catches." Failure mode effects and analyses can be used to proactively identify and mitigate areas of highest risk, and methods drawn from cognitive psychology, simulation training, and human factor engineering can be used to advance facility safety. © 2015 Wiley Periodicals, Inc.

Extension of sonic anemometry to high subsonic Mach number flows

NASA Astrophysics Data System (ADS)

Otero, R.; Lowe, K. T.; Ng, W. F.

2017-03-01

In the literature, the application of sonic anemometry has been limited to low subsonic Mach number, near-incompressible flow conditions. To the best of the authors’ knowledge, this paper represents the first time a sonic anemometry approach has been used to characterize flow velocity beyond Mach 0.3. Using a high speed jet, flow velocity was measured using a modified sonic anemometry technique in flow conditions up to Mach 0.83. A numerical study was conducted to identify the effects of microphone placement on the accuracy of the measured velocity. Based on estimated error strictly due to uncertainty in time-of-acoustic flight, a random error of +/- 4 m s-1 was identified for the configuration used in this experiment. Comparison with measurements from a Pitot probe indicated a velocity RMS error of +/- 9 m s-1. The discrepancy in error is attributed to a systematic error which may be calibrated out in future work. Overall, the experimental results from this preliminary study support the use of acoustics for high subsonic flow characterization.

Characterization of the International Linear Collider damping ring optics

NASA Astrophysics Data System (ADS)

Shanks, J.; Rubin, D. L.; Sagan, D.

2014-10-01

A method is presented for characterizing the emittance dilution and dynamic aperture for an arbitrary closed lattice that includes guide field magnet errors, multipole errors and misalignments. This method, developed and tested at the Cornell Electron Storage Ring Test Accelerator (CesrTA), has been applied to the damping ring lattice for the International Linear Collider (ILC). The effectiveness of beam based emittance tuning is limited by beam position monitor (BPM) measurement errors, number of corrector magnets and their placement, and correction algorithm. The specifications for damping ring magnet alignment, multipole errors, number of BPMs, and precision in BPM measurements are shown to be consistent with the required emittances and dynamic aperture. The methodology is then used to determine the minimum number of position monitors that is required to achieve the emittance targets, and how that minimum depends on the location of the BPMs. Similarly, the maximum tolerable multipole errors are evaluated. Finally, the robustness of each BPM configuration with respect to random failures is explored.

Visual, Physiological, and Aesthetic Factors and Pitfalls in Asian Blepharoplasty

PubMed Central

Chen, William Pai-Dei

2016-01-01

Double eyelid surgery to create an upper-lid crease in Asian patients is one of the more popular aesthetic surgeries among people of Asian descent. Much has been written about the myriad methods, but little has been written about the underlying factors that predispose a patient to complications and suboptimal results. This article touches on some of the possible errors in placement of crease height in upper blepharoplasty and the pitfalls that can be associated with permanent placement of nondissolvable sutures that encircle the complex layers of the upper eyelid, as well as the ideal eyelid crease wound closure and its biodynamics. One should consider these factors in any form of upper eyelid procedure, as they are not merely applicable to upper blepharoplasty. PMID:26673576

Gait parameter and event estimation using smartphones.

PubMed

Pepa, Lucia; Verdini, Federica; Spalazzi, Luca

2017-09-01

The use of smartphones can greatly help for gait parameters estimation during daily living, but its accuracy needs a deeper evaluation against a gold standard. The objective of the paper is a step-by-step assessment of smartphone performance in heel strike, step count, step period, and step length estimation. The influence of smartphone placement and orientation on estimation performance is evaluated as well. This work relies on a smartphone app developed to acquire, process, and store inertial sensor data and rotation matrices about device position. Smartphone alignment was evaluated by expressing the acceleration vector in three reference frames. Two smartphone placements were tested. Three methods for heel strike detection were considered. On the basis of estimated heel strikes, step count is performed, step period is obtained, and the inverted pendulum model is applied for step length estimation. Pearson correlation coefficient, absolute and relative errors, ANOVA, and Bland-Altman limits of agreement were used to compare smartphone estimation with stereophotogrammetry on eleven healthy subjects. High correlations were found between smartphone and stereophotogrammetric measures: up to 0.93 for step count, to 0.99 for heel strike, 0.96 for step period, and 0.92 for step length. Error ranges are comparable to those in the literature. Smartphone placement did not affect the performance. The major influence of acceleration reference frames and heel strike detection method was found in step count. This study provides detailed information about expected accuracy when smartphone is used as a gait monitoring tool. The obtained results encourage real life applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Percutaneous lumbar sympathectomy: A comparison of radiofrequency denervation versus phenol neurolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haynsworth, R.F. Jr.; Noe, C.E.

A new percutaneous approach to sympathectomy using radiofrequency denervation has seemed to offer longer duration and less incidence of postsympathetic neuralgia as compared to phenol sympathetic blocks. To compare these techniques, 17 patients underwent either phenol lumbar sympathetic blocks (n = 9) or radiofrequency denervation (n = 8). Duration of sympathetic block was followed by a sweat test and temperature measurements. Results indicate that 89% of patients in the phenol group showed signs of sympathetic blockade after 8 weeks, as compared to 12% in the radiofrequency group (P less than 0.05). Although the incidence of post sympathetic neuralgia appears tomore » be less with radiofrequency denervation, further refinement of needle placement to ensure complete lesioning of the sympathetic chain will be required before the technique can offer advantages over current phenol techniques.« less

The muscle biopsy technique. Historical and methodological considerations.

PubMed

Ekblom, B

2017-05-01

The muscle biopsy method is an important tool for clinical and scientific work. In this study, the two most used instruments, the Bergström needle and the Well-Blakesley conchotome, are described. The technique of using those instruments, risks, and other considerations are discussed. Finally, a few consequences and the error of the method for determining muscle fiber type, fiber area, substrates, and metabolites are presented. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A global CT to US registration of the lumbar spine

NASA Astrophysics Data System (ADS)

Nagpal, Simrin; Hacihaliloglu, Ilker; Ungi, Tamas; Rasoulian, Abtin; Osborn, Jill; Lessoway, Victoria A.; Rohling, Robert N.; Borschneck, Daniel P.; Abolmaesumi, Purang; Mousavi, Parvin

2014-03-01

During percutaneous lumbar spine needle interventions, alignment of the preoperative computed tomography (CT) with intraoperative ultrasound (US) can augment anatomical visualization for the clinician. We propose an approach to rigidly align CT and US data of the lumbar spine. The approach involves an intensity-based volume registration step, followed by a surface segmentation and a point-based registration of the entire lumbar spine volume. A clinical feasibility study resulted in mean registration error of approximately 3 mm between CT and US data.

Heterologous Array Analysis in Pinaceae: Hybridization of Pinus Taeda cDNA Arrays With cDNA From Needles and Embryogenic Cultures of P. Taeda, P. Sylvestris or Picea Abies

PubMed Central

van Zyl, Leonel; von Arnold, Sara; Bozhkov, Peter; Chen, Yongzhong; Egertsdotter, Ulrika; MacKay, John; Sederoff, Ronald R.; Shen, Jing; Zelena, Lyubov

2002-01-01

Hybridization of labelled cDNA from various cell types with high-density arrays of expressed sequence tags is a powerful technique for investigating gene expression. Few conifer cDNA libraries have been sequenced. Because of the high level of sequence conservation between Pinus and Picea we have investigated the use of arrays from one genus for studies of gene expression in the other. The partial cDNAs from 384 identifiable genes expressed in differentiating xylem of Pinus taeda were printed on nylon membranes in randomized replicates. These were hybridized with labelled cDNA from needles or embryogenic cultures of Pinus taeda, P. sylvestris and Picea abies, and with labelled cDNA from leaves of Nicotiana tabacum. The Spearman correlation of gene expression for pairs of conifer species was high for needles (r2 = 0.78 − 0.86), and somewhat lower for embryogenic cultures (r2 = 0.68 − 0.83). The correlation of gene expression for tobacco leaves and needles of each of the three conifer species was lower but sufficiently high (r2 = 0.52 − 0.63) to suggest that many partial gene sequences are conserved in angiosperms and gymnosperms. Heterologous probing was further used to identify tissue-specific gene expression over species boundaries. To evaluate the significance of differences in gene expression, conventional parametric tests were compared with permutation tests after four methods of normalization. Permutation tests after Z-normalization provide the highest degree of discrimination but may enhance the probability of type I errors. It is concluded that arrays of cDNA from loblolly pine are useful for studies of gene expression in other pines or spruces. PMID:18629264

Donor anxiety, needle pain, and syncopal reactions combine to determine retention: a path analysis of two-year donor return data.

PubMed

France, Christopher R; France, Janis L; Wissel, Mary Ellen; Ditto, Blaine; Dickert, Tara; Himawan, Lina K

2013-09-01

Efforts to expand the donor pool by recruiting younger donors have resulted in higher numbers of initial donations, but retention of young donors continues to be challenging. Path analysis was used to examine the simultaneous relationships among syncopal reactions, donation anxiety, needle pain, donor satisfaction, and donation intention in predicting repeat donation. Participants included 421 first- and second-time donors recruited for a study comparing the effects of predonation water loading with and without the use of applied muscle tension during donation (52% female, 60.8% first-time donor, mean age 20.3 years). For this longitudinal follow-up study, donor database records were accessed 2 years after the index donation to assess repeat donation. Results of a series of path analyses demonstrated the influential role of donor anxiety in shaping donor retention (final model χ(2) = 35.75, root mean square error of approximation 0.03, comparative fit index 0.98, weighted root mean square residual 0.74). First, anxiety exerted a direct negative influence on donation intention, the proximal and sole direct predictor of repeat donation. Second, anxiety increased the likelihood of donor-reported needle pain, adversely affecting donation satisfaction and, subsequently, donation intention. Finally, anxiety was associated with donor ratings of syncopal reactions through its impact on needle pain, which also contributed to decreased donation intention. These results provide novel evidence that donation anxiety plays a central role in shaping future donation behavior. Individual differences in anxiety must be considered when developing and testing strategies to enhance blood donor retention. © 2013 American Association of Blood Banks.

Fixing Stellarator Magnetic Surfaces

NASA Astrophysics Data System (ADS)

Hanson, James D.

1999-11-01

Magnetic surfaces are a perennial issue for stellarators. The design heuristic of finding a magnetic field with zero perpendicular component on a specified outer surface often yields inner magnetic surfaces with very small resonant islands. However, magnetic fields in the laboratory are not design fields. Island-causing errors can arise from coil placement errors, stray external fields, and design inadequacies such as ignoring coil leads and incomplete characterization of current distributions within the coil pack. The problem addressed is how to eliminate such error-caused islands. I take a perturbation approach, where the zero order field is assumed to have good magnetic surfaces, and comes from a VMEC equilibrium. The perturbation field consists of error and correction pieces. The error correction method is to determine the correction field so that the sum of the error and correction fields gives zero island size at specified rational surfaces. It is particularly important to correctly calculate the island size for a given perturbation field. The method works well with many correction knobs, and a Singular Value Decomposition (SVD) technique is used to determine minimal corrections necessary to eliminate islands.

Validation of elastic registration algorithms based on adaptive irregular grids for medical applications

NASA Astrophysics Data System (ADS)

Franz, Astrid; Carlsen, Ingwer C.; Renisch, Steffen; Wischmann, Hans-Aloys

2006-03-01

Elastic registration of medical images is an active field of current research. Registration algorithms have to be validated in order to show that they fulfill the requirements of a particular clinical application. Furthermore, validation strategies compare the performance of different registration algorithms and can hence judge which algorithm is best suited for a target application. In the literature, validation strategies for rigid registration algorithms have been analyzed. For a known ground truth they assess the displacement error at a few landmarks, which is not sufficient for elastic transformations described by a huge number of parameters. Hence we consider the displacement error averaged over all pixels in the whole image or in a region-of-interest of clinical relevance. Using artificially, but realistically deformed images of the application domain, we use this quality measure to analyze an elastic registration based on transformations defined on adaptive irregular grids for the following clinical applications: Magnetic Resonance (MR) images of freely moving joints for orthopedic investigations, thoracic Computed Tomography (CT) images for the detection of pulmonary embolisms, and transmission images as used for the attenuation correction and registration of independently acquired Positron Emission Tomography (PET) and CT images. The definition of a region-of-interest allows to restrict the analysis of the registration accuracy to clinically relevant image areas. The behaviour of the displacement error as a function of the number of transformation control points and their placement can be used for identifying the best strategy for the initial placement of the control points.

In vivo reproducibility of robotic probe placement for a novel ultrasound-guided radiation therapy system

PubMed Central

Lediju Bell, Muyinatu A.; Sen, H. Tutkun; Iordachita, Iulian; Kazanzides, Peter; Wong, John

2014-01-01

Abstract. Ultrasound can provide real-time image guidance of radiation therapy, but the probe-induced tissue deformations cause local deviations from the treatment plan. If placed during treatment planning, the probe causes streak artifacts in required computed tomography (CT) images. To overcome these challenges, we propose robot-assisted placement of an ultrasound probe, followed by replacement with a geometrically identical, CT-compatible model probe. In vivo reproducibility was investigated by implanting a canine prostate, liver, and pancreas with three 2.38-mm spherical markers in each organ. The real probe was placed to visualize the markers and subsequently replaced with the model probe. Each probe was automatically removed and returned to the same position or force. Under position control, the median three-dimensional reproducibility of marker positions was 0.6 to 0.7 mm, 0.3 to 0.6 mm, and 1.1 to 1.6 mm in the prostate, liver, and pancreas, respectively. Reproducibility was worse under force control. Probe substitution errors were smallest for the prostate (0.2 to 0.6 mm) and larger for the liver and pancreas (4.1 to 6.3 mm), where force control generally produced larger errors than position control. Results indicate that position control is better than force control for this application, and the robotic approach has potential, particularly for relatively constrained organs and reproducibility errors that are smaller than established treatment margins. PMID:26158038

Catheter orifice configuration influences the effectiveness of continuous peripheral nerve blockade.

PubMed

Fredrickson, Michael J; Ball, Craig M; Dalgleish, Adam J

2011-01-01

We investigated perineural catheter threading distance and orifice configuration during continuous interscalene analgesia. One hundred fifty-three patients receiving an anterolateral interscalene catheter (catheter needle and nerve/plexus in a similar alignment) for elective shoulder surgery were randomized to 1 of 3 groups: following out-of-plane ultrasound confirmation of the needle tip immediately lateral to the C5/6 roots, a nonstimulating catheter was blindly advanced 0.5 cm (end-hole; n = 50), 2.5 cm (multiorifice; n = 50) or 5 cm (multiorifice; n = 53) beyond the needle tip. Ropivacaine 0.75% + lidocaine 1% (50:50) 20 mL was administered preoperatively via the catheter before surgery under general anesthesia. A ropivacaine 0.2% 2 mL/hr elastomeric infusion with mandatory 6 hourly (and on demand) 5-mL boluses was continued for more than 48 hrs with tramadol available as rescue. Patients were questioned in the recovery room, at 24 and 48 hrs for numerical rating pain score (0-10), ropivacaine bolus, and tramadol consumption. Patients were more frequently pain-free in the recovery room in the multiorifice 2.5 and 5 cm groups compared with the end-hole 0.5 cm group (94%, 91% vs 66%; P < 0.001). During the first 24 hrs, the end-hole group demonstrated an earlier time to first pain (median, 10 vs17, 15 hrs; P < 0.001), higher "average pain" (median, 3 vs 1, 2, P = 0.004), and more ropivacaine bolus (median, 5 vs 3, 3; P < 0.001) and tramadol consumption (P = 0.01). Groups 2.5 and 5 cm did not significantly differ in any outcomes. These results suggest that multiorifice catheters provide superior intermittent bolus continuous peripheral nerve blockade compared with end-hole catheters. For anterolateral approach interscalene catheter placement, there is minimal benefit, either way, to 2.5- or 5-cm blind catheter advancement.

A Randomized Trial Comparing Acupuncture, Simulated Acupuncture, and Usual Care for Chronic Low Back Pain

PubMed Central

Cherkin, Daniel C.; Sherman, Karen J.; Avins, Andrew L.; Erro, Janet H.; Ichikawa, Laura; Barlow, William E.; Delaney, Kristin; Hawkes, Rene; Hamilton, Luisa; Pressman, Alice; Khalsa, Partap S.; Deyo, Richard A.

2009-01-01

Background Acupuncture is a popular complementary and alternative treatment for chronic back pain. Recent European trials suggest similar short-term benefits from real and sham acupuncture needling. This trial addresses the importance of needle placement and skin penetration in eliciting acupuncture effects for patients with chronic low back pain. Methods 638 adults with chronic mechanical low back pain were randomized to: individualized acupuncture, standardized acupuncture, simulated acupuncture, or usual care. Ten treatments were provided over 7 weeks by experienced acupuncturists. The primary outcomes were back-related dysfunction (Roland Disability score, range: 0 to 23) and symptom bothersomeness (0 to 10 scale). Outcomes were assessed at baseline and after 8, 26 and 52 weeks. Results At 8 weeks, mean dysfunction scores for the individualized, standardized, and simulated acupuncture groups improved by 4.4, 4.5, and 4.4 points, respectively, compared with 2.1 points for those receiving usual care (P<0.001). Participants receiving real or simulated acupuncture were more likely than those receiving usual care to experience clinically meaningful improvements on the dysfunction scale (60% vs. 39%, P<0.0001). Symptoms improved by 1.6 to 1.9 points in the treatment groups compared with 0.7 points in the usual care group (P<0.0001). After one year, participants in the treatment groups were more likely than those receiving usual care group to experience clinically meaningful improvements in dysfunction (59% to 65% versus 50%, respectively, P=0.02) but not in symptoms (P>0.05). Conclusions Although acupuncture was found effective for chronic low back pain, tailoring needling sites to each patient and penetration of the skin appear to be unimportant in eliciting therapeutic benefits. These findings raise questions about acupuncture’s purported mechanisms of action. It remains unclear whether acupuncture, or our simulated method of acupuncture, provide physiologically important stimulation or represent placebo or non-specific effects. PMID:19433697

Fluoroscopically guided infiltration of the cervical nerve root: an indirect approach through the ipsilateral facet joint.

PubMed

Kelekis, Alexios; Filippiadis, Dimitrios K; Velonakis, Georgios; Martin, Jean-Baptist; Oikonomopoulos, Nikolaos; Brountzos, Elias; Kelekis, Nikolaos

2014-01-01

Transforaminal infiltrations in the cervical spine are governed by a higher rate of vascular puncture than in the lumbar spine. The purpose of our study is to assess the safety and efficacy of percutaneous, fluoroscopically guided nerve root infiltrations in cases of cervical radiculopathy. An indirect postero-lateral approach was performed through the ipsilateral facet joint. During the last 2 years, 25 patients experiencing cervical radiculopathy underwent percutaneous, fluoroscopically guided nerve root infiltrations by means of an indirect postero-lateral approach through the ipsilateral facet joint. The intra-articular position of the needle (22-gauge spinal needle) was fluoroscopically verified after injection of a small amount of contrast medium which also verified dispersion of the contrast medium periradicularly and in the epidural space. Then a mixture of long-acting glucocorticosteroid diluted in normal saline (1.5/1 mL) was injected intra-articularly. A questionnaire with a Numeric Visual Scale (NVS) scale helped assess pain relief, life quality, and mobility improvement. A mean of 2.3 sessions was performed in the patients of our study. In the vast majority of our patients 19/25 (76%), the second infiltration was performed within 7-10 days of the first one. Comparing the pain scores prior (mean value 8.80 ± 1.080 NVS units) and after (mean value 1.84 ± 1.405 NVS units), there was a mean decrease of 6.96 ± 1.695 NVS units [median value 7 NVS units (P < 0.001) in terms of pain reduction, effect upon mobility, and life quality. There were no clinically significant complications noted in our study. Fluoroscopically guided transforaminal infiltrations through the ipsilateral facet joint seem to be a feasible, efficacious, and safe approach for the treatment of patients with cervical radiculopathy. This approach facilitates needle placement and minimizes risk of complications.

Comparison of intraoperative dosimetric implant representation with postimplant dosimetry in patients receiving prostate brachytherapy.

PubMed

Stone, Nelson N; Hong, Suzanne; Lo, Yeh-Chi; Howard, Victor; Stock, Richard G

2003-01-01

To compare the results of intraoperative dosimetry with those of CT-based postimplant dosimetry in patients undergoing prostate seed implantation. Seventy-seven patients with T1-T3 prostate cancer received an ultrasound-guided permanent seed implant (36 received (125)I, 7 (103)Pd, and 34 a partial (103)Pd implant plus external beam radiation therapy). The implantation was augmented with an intraoperative dosimetric planning system. After the peripheral needles were placed, 5-mm axial images were acquired into the treatment planning system. Soft tissue structures (prostate, urethra, and rectum) were contoured, and exact needle positions were registered. Seeds were placed with an applicator, and their positions were entered into the planning system. The dose distributions for the implant were calculated after interior needle and seed placement. Postimplant dosimetry was performed 1 month later on the basis of CT imaging. Prostate and urethral doses were compared, by using paired t tests, for the real-time dosimetry in the operating room (OR) and the postimplant dosimetry. The mean preimplant prostate volume was 39.8 cm(3), the postneedle planning volume was 41.5 cm(3) (p<0.001), and the 1-month CT volume was 43.6 cm(3) (p<0.001). The mean difference between the OR dose received by 90% of the prostate (D(90)) and the CT D(90) was 3.4% (95% confidence interval, 2.5-6.6%; p=0.034). The mean dose to 30% of the urethra was 120% of prescription in the OR and 138% on CT. The mean difference was 18% (95% confidence interval, 13-24%; p<0.001). Although small differences exist between the OR and CT dosimetry results, these data suggest that this intraoperative implant dosimetric representation system provides a close match to the actual delivered doses. These data support the use of this system to modify the implant during surgery to achieve more consistent dosimetry results.

Accessible bioprinting: adaptation of a low-cost 3D-printer for precise cell placement and stem cell differentiation.

PubMed

Reid, John A; Mollica, Peter A; Johnson, Garett D; Ogle, Roy C; Bruno, Robert D; Sachs, Patrick C

2016-06-07

The precision and repeatability offered by computer-aided design and computer-numerically controlled techniques in biofabrication processes is quickly becoming an industry standard. However, many hurdles still exist before these techniques can be used in research laboratories for cellular and molecular biology applications. Extrusion-based bioprinting systems have been characterized by high development costs, injector clogging, difficulty achieving small cell number deposits, decreased cell viability, and altered cell function post-printing. To circumvent the high-price barrier to entry of conventional bioprinters, we designed and 3D printed components for the adaptation of an inexpensive 'off-the-shelf' commercially available 3D printer. We also demonstrate via goal based computer simulations that the needle geometries of conventional commercially standardized, 'luer-lock' syringe-needle systems cause many of the issues plaguing conventional bioprinters. To address these performance limitations we optimized flow within several microneedle geometries, which revealed a short tapered injector design with minimal cylindrical needle length was ideal to minimize cell strain and accretion. We then experimentally quantified these geometries using pulled glass microcapillary pipettes and our modified, low-cost 3D printer. This systems performance validated our models exhibiting: reduced clogging, single cell print resolution, and maintenance of cell viability without the use of a sacrificial vehicle. Using this system we show the successful printing of human induced pluripotent stem cells (hiPSCs) into Geltrex and note their retention of a pluripotent state 7 d post printing. We also show embryoid body differentiation of hiPSC by injection into differentiation conducive environments, wherein we observed continuous growth, emergence of various evaginations, and post-printing gene expression indicative of the presence of all three germ layers. These data demonstrate an accessible open-source 3D bioprinter capable of serving the needs of any laboratory interested in 3D cellular interactions and tissue engineering.

NADH-fluorescence scattering correction for absolute concentration determination in a liquid tissue phantom using a novel multispectral magnetic-resonance-imaging-compatible needle probe

NASA Astrophysics Data System (ADS)

Braun, Frank; Schalk, Robert; Heintz, Annabell; Feike, Patrick; Firmowski, Sebastian; Beuermann, Thomas; Methner, Frank-Jürgen; Kränzlin, Bettina; Gretz, Norbert; Rädle, Matthias

2017-07-01

In this report, a quantitative nicotinamide adenine dinucleotide hydrate (NADH) fluorescence measurement algorithm in a liquid tissue phantom using a fiber-optic needle probe is presented. To determine the absolute concentrations of NADH in this phantom, the fluorescence emission spectra at 465 nm were corrected using diffuse reflectance spectroscopy between 600 nm and 940 nm. The patented autoclavable Nitinol needle probe enables the acquisition of multispectral backscattering measurements of ultraviolet, visible, near-infrared and fluorescence spectra. As a phantom, a suspension of calcium carbonate (Calcilit) and water with physiological NADH concentrations between 0 mmol l-1 and 2.0 mmol l-1 were used to mimic human tissue. The light scattering characteristics were adjusted to match the backscattering attributes of human skin by modifying the concentration of Calcilit. To correct the scattering effects caused by the matrices of the samples, an algorithm based on the backscattered remission spectrum was employed to compensate the influence of multiscattering on the optical pathway through the dispersed phase. The monitored backscattered visible light was used to correct the fluorescence spectra and thereby to determine the true NADH concentrations at unknown Calcilit concentrations. Despite the simplicity of the presented algorithm, the root-mean-square error of prediction (RMSEP) was 0.093 mmol l-1.

CT, MR, and ultrasound image artifacts from prostate brachytherapy seed implants: The impact of seed size

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Andrew K. H.; Basran, Parminder S.; Thomas, Steven D.

Purpose: To investigate the effects of brachytherapy seed size on the quality of x-ray computed tomography (CT), ultrasound (US), and magnetic resonance (MR) images and seed localization through comparison of the 6711 and 9011 {sup 125}I sources. Methods: For CT images, an acrylic phantom mimicking a clinical implantation plan and embedded with low contrast regions of interest (ROIs) was designed for both the 0.774 mm diameter 6711 (standard) and the 0.508 mm diameter 9011 (thin) seed models (Oncura, Inc., and GE Healthcare, Arlington Heights, IL). Image quality metrics were assessed using the standard deviation of ROIs between the seeds andmore » the contrast to noise ratio (CNR) within the low contrast ROIs. For US images, water phantoms with both single and multiseed arrangements were constructed for both seed sizes. For MR images, both seeds were implanted into a porcine gel and imaged with pelvic imaging protocols. The standard deviation of ROIs and CNR values were used as metrics of artifact quantification. Seed localization within the CT images was assessed using the automated seed finder in a commercial brachytherapy treatment planning system. The number of erroneous seed placements and the average and maximum error in seed placements were recorded as metrics of the localization accuracy. Results: With the thin seeds, CT image noise was reduced from 48.5 {+-} 0.2 to 32.0 {+-} 0.2 HU and CNR improved by a median value of 74% when compared with the standard seeds. Ultrasound image noise was measured at 50.3 {+-} 17.1 dB for the thin seed images and 50.0 {+-} 19.8 dB for the standard seed images, and artifacts directly behind the seeds were smaller and less prominent with the thin seed model. For MR images, CNR of the standard seeds reduced on average 17% when using the thin seeds for all different imaging sequences and seed orientations, but these differences are not appreciable. Automated seed localization required an average ({+-}SD) of 7.0 {+-} 3.5 manual corrections in seed positions for the thin seed scans and 3.0 {+-} 1.2 manual corrections in seed positions for the standard seed scans. The average error in seed placement was 1.2 mm for both seed types and the maximum error in seed placement was 2.1 mm for the thin seed scans and 1.8 mm for the standard seed scans. Conclusions: The 9011 thin seeds yielded significantly improved image quality for CT and US images but no significant differences in MR image quality.« less

Comments on stellar boundary cooling and the reality of supermetallicity

NASA Technical Reports Server (NTRS)

Deming, D.

1980-01-01

The paper discusses the 'super-metal-rich' (SMR) stars and reexamines Peterson's analysis of the SMR prototype mu Leo (1978) with regard to a postulated error in continuum error. Model atmospheres are used to compute theoretical equivalent widths and to explore the sensitivity of these widths to metallicity, temperature, surface gravity, and microturbulence. It is shown that Peterson's results are sensitive to continuum placement, and that her data does not indicate that the temperature gradient is steeper in mu Leo than in normal giants. It is concluded that the SMR stars are very metal rich and are also somewhat boundary cooled, possibly due to high metallicity.

EUV via hole pattern fidelity enhancement through novel resist and post-litho plasma treatment

NASA Astrophysics Data System (ADS)

Yaegashi, Hidetami; Koike, Kyohei; Fonseca, Carlos; Yamashita, Fumiko; Kaushik, Kumar; Morikita, Shinya; Ito, Kiyohito; Yoshimura, Shota; Timoshkov, Vadim; Maslow, Mark; Jee, Tae Kwon; Reijnen, Liesbeth; Choi, Peter; Feng, Mu; Spence, Chris; Schoofs, Stijn

2018-03-01

Extreme UV(EUV) technology must be potential solution for sustainable scaling, and its adoption in high volume manufacturing(HVM) is getting realistic more and more. This technology has a wide capability to mitigate various technical problem in Multi-patterning (LELELE) for via hole patterning with 193-i. It induced local pattern fidelity error such like CDU, CER, Pattern placement error. Exactly, EUV must be desirable scaling-driving tool, however, specific technical issue, named RLS (Resolution-LER-Sensitivity) triangle, obvious remaining issue. In this work, we examined hole patterning sensitizing (Lower dose approach) utilizing hole patterning restoration technique named "CD-Healing" as post-Litho. treatment.

Convergence of fractional adaptive systems using gradient approach.

PubMed

Gallegos, Javier A; Duarte-Mermoud, Manuel A

2017-07-01

Conditions for boundedness and convergence of the output error and the parameter error for various Caputo's fractional order adaptive schemes based on the steepest descent method are derived in this paper. To this aim, the concept of sufficiently exciting signals is introduced, characterized and related to the concept of persistently exciting signals used in the integer order case. An application is designed in adaptive indirect control of integer order systems using fractional equations to adjust parameters. This application is illustrated for a pole placement adaptive problem. Advantages of using fractional adjustment in control adaptive schemes are experimentally obtained. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Injection device-related risk management toward safe administration of medications: experience in a university teaching hospital in The People's Republic of China.

PubMed

Zhu, Ling-Ling; Li, Wei; Song, Ping; Zhou, Quan

2014-01-01

The use of injection devices to administer intravenous or subcutaneous medications is common practice throughout a variety of health care settings. Studies suggest that one-half of all harmful medication errors originate during drug administration; of those errors, about two-thirds involve injectables. Therefore, injection device management is pivotal to safe administration of medications. In this article, the authors summarize the relevant experiences by retrospective analysis of injection device-related near misses and adverse events in the Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang University, People's Republic of China. Injection device-related near misses and adverse events comprised the following: 1) improper selection of needle diameter for subcutaneous injection, material of infusion sets, and pore size of in-line filter; 2) complications associated with vascular access; 3) incidents induced by absence of efficient electronic pump management and infusion tube management; and 4) liquid leakage of chemotherapeutic infusion around the syringe needle. Safe injection drug use was enhanced by multidisciplinary collaboration, especially among pharmacists and nurses; drafting of clinical pathways in selection of vascular access; application of approaches such as root cause analysis using a fishbone diagram; plan-do-check-act and quality control circle; and construction of a culture of spontaneous reporting of near misses and adverse events. Pharmacists must be professional in regards to medication management and use. The depth, breadth, and efficiency of cooperation between nurses and pharmacists are pivotal to injection safety.

Effects of implantation method and temperature on mortality and loss of simulated transmitters in hybrid striped bass

USGS Publications Warehouse

Walsh, M.G.; Bjorgo, K.A.; Isely, J.J.

2000-01-01

To determine the effects of surgical implantation method and temperature on mortality and transmitter loss, we compared two antenna placements (trailing antenna versus shielded needle) and two suture materials (absorbable versus nonabsorbable) in hybrid striped bass Morone saxitilis x Morone chrysops (227-410 mm total length) that had been surgically implanted with simulated transmitters and held at high (22-29??C) and low (12-18??C) temperatures for 120 d. Fish were individually examined after 7, 30, 60. 90. and 120 d to evaluate suture and wound condition as well as transmitter loss. Neither suture material nor antenna placement affected transmitter loss, mortality, or growth at either high or low temperatures. Absorbable sutures were lost more quickly than were nonabsorbable sutures, but they persisted beyond incision closure at both high and low temperatures. At high temperatures, 50% suture loss occurred by 30 d for absorbable sutures and by 60 d for nonabsorbable sutures. Mortality occurred only at high temperatures but was delayed and was likely caused by peritoneal infection. Transmitter loss was not significant; it occurred only in the low-temperature trial and was caused by pressure necrosis at the incision rather than by suture failure. Temperature significantly affected all responses examined in this study. Significant irritation, infection, and mortality occurred in all treatment groups at high temperatures.

A marker placement laser device for improving repeatability in 3D-foot motion analysis.

PubMed

Kalkum, Eva; van Drongelen, Stefan; Mussler, Johannes; Wolf, Sebastian I; Kuni, Benita

2016-02-01

In 3D gait analysis, the repeated positioning of markers is associated with a high error rate, particularly when using a complex foot model with many markers. Therefore, a marker placement laser device was developed that ensures a reliable repositioning of markers. We report the development and reliability of this device for the foot at different tape conditions. In 38 subjects, markers were placed at the foot according to the Heidelberg foot measurement method. Subjects were tested barefoot and barefoot with three different tape conditions. For all conditions, a static standing trial was captured. We analyzed differences in distances between markers and the intra-class correlation coefficients (ICC). Small differences between the conditions (0.03-3.28 mm) and excellent ICCs (0.91-0.97 mm) were found for all parameters. The laser marker placement device appeared to be a reliable method to place markers on a tape at previously palpated positions and ensures an exact position. The device could find a wide application in different clinical research fields. Copyright © 2015 Elsevier B.V. All rights reserved.

Lessons learned: wrong intraocular lens.

PubMed

Schein, Oliver D; Banta, James T; Chen, Teresa C; Pritzker, Scott; Schachat, Andrew P

2012-10-01

To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. Retrospective small case series, convenience sample. Seven surgical cases. Institutional review of errors committed and subsequent improvements to clinical protocols. Lessons learned and changes in procedures adapted. The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Lower-limb amputee ankle and hip kinetic response to an imposed error in mediolateral foot placement.

PubMed

Segal, Ava D; Shofer, Jane B; Klute, Glenn K

2015-11-26

Maintaining balance while walking is challenging for lower limb amputees. The effect of prosthetic foot stiffness on recovery kinetics from an error in foot placement may inform prescription practice and lead to new interventions designed to improve balance. Ten unilateral transtibial amputees were fit with two prosthetic feet with different stiffness properties in random order. After a 3-week acclimation period, they returned to the lab for testing before switching feet. Twelve non-amputees also participated in a single data collection. While walking on an instrumented treadmill, we imposed a repeatable, unexpected medial or lateral disturbance in foot placement by releasing a burst of air at the ankle just before heel strike. Three-dimensional motion capture, ground reaction force and center of pressure (COP) data were collected for two steps prior, the disturbed step and three steps after the disturbance. During undisturbed walking, coronal ankle impulse was lower by 42% for amputees wearing a stiff compared to a compliant foot (p=0.017); however, across steps, both prosthetic recovery patterns were similar compared to the sound limb and non-amputees. Peak coronal hip moment was 15-20% lower for both foot types during undisturbed walking (p<0.001), with less change in response to the medial disturbance (p<0.001) compared to the sound limb and non-amputees. Amputee prosthetic COP excursion was unaffected by the disturbance (2.4% change) compared to the sound limb (59% change; p<0.001) and non-amputees (55% change; p<0.001). These findings imply that a prosthetic foot-ankle system able to contribute to ankle kinetics may improve walking balance among amputees. Published by Elsevier Ltd.

Aortic blood pressure measured via EIT: investigation of different measurement settings.

PubMed

Braun, Fabian; Proença, Martin; Rapin, Michael; Lemay, Mathieu; Adler, Andy; Grychtol, Bartłomiej; Solà, Josep; Thiran, Jean-Philippe

2015-06-01

Electrical impedance tomography (EIT) allows the measurement of intra-thoracic impedance changes related to cardiovascular activity. As a safe and low-cost imaging modality, EIT is an appealing candidate for non-invasive and continuous haemodynamic monitoring. EIT has recently been shown to allow the assessment of aortic blood pressure via the estimation of the aortic pulse arrival time (PAT). However, finding the aortic signal within EIT image sequences is a challenging task: the signal has a small amplitude and is difficult to locate due to the small size of the aorta and the inherent low spatial resolution of EIT. In order to most reliably detect the aortic signal, our objective was to understand the effect of EIT measurement settings (electrode belt placement, reconstruction algorithm). This paper investigates the influence of three transversal belt placements and two commonly-used difference reconstruction algorithms (Gauss-Newton and GREIT) on the measurement of aortic signals in view of aortic blood pressure estimation via EIT. A magnetic resonance imaging based three-dimensional finite element model of the haemodynamic bio-impedance properties of the human thorax was created. Two simulation experiments were performed with the aim to (1) evaluate the timing error in aortic PAT estimation and (2) quantify the strength of the aortic signal in each pixel of the EIT image sequences. Both experiments reveal better performance for images reconstructed with Gauss-Newton (with a noise figure of 0.5 or above) and a belt placement at the height of the heart or higher. According to the noise-free scenarios simulated, the uncertainty in the analysis of the aortic EIT signal is expected to induce blood pressure errors of at least ± 1.4 mmHg.

Alternate methods for FAAT S-curve generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaufman, A.M.

The FAAT (Foreign Asset Assessment Team) assessment methodology attempts to derive a probability of effect as a function of incident field strength. The probability of effect is the likelihood that the stress put on a system exceeds its strength. In the FAAT methodology, both the stress and strength are random variables whose statistical properties are estimated by experts. Each random variable has two components of uncertainty: systematic and random. The systematic uncertainty drives the confidence bounds in the FAAT assessment. Its variance can be reduced by improved information. The variance of the random uncertainty is not reducible. The FAAT methodologymore » uses an assessment code called ARES to generate probability of effect curves (S-curves) at various confidence levels. ARES assumes log normal distributions for all random variables. The S-curves themselves are log normal cumulants associated with the random portion of the uncertainty. The placement of the S-curves depends on confidence bounds. The systematic uncertainty in both stress and strength is usually described by a mode and an upper and lower variance. Such a description is not consistent with the log normal assumption of ARES and an unsatisfactory work around solution is used to obtain the required placement of the S-curves at each confidence level. We have looked into this situation and have found that significant errors are introduced by this work around. These errors are at least several dB-W/cm{sup 2} at all confidence levels, but they are especially bad in the estimate of the median. In this paper, we suggest two alternate solutions for the placement of S-curves. To compare these calculational methods, we have tabulated the common combinations of upper and lower variances and generated the relevant S-curves offsets from the mode difference of stress and strength.« less

Needle Biopsy

MedlinePlus

... needle biopsy procedures include fine-needle aspiration and core needle biopsy. Needle biopsy may be used to ... hollow needle to draw cells from your body. Core needle biopsy. This type of needle biopsy uses ...

Derivation of a Performance Checklist for Ultrasound-Guided Arthrocentesis Using the Modified Delphi Method.

PubMed

Kunz, Derek; Pariyadath, Manoj; Wittler, Mary; Askew, Kim; Manthey, David; Hartman, Nicholas

2017-06-01

Arthrocentesis is an important skill for physicians in multiple specialties. Recent studies indicate a superior safety and performance profile for this procedure using ultrasound guidance for needle placement, and improving quality of care requires a valid measurement of competency using this modality. We endeavored to create a validated tool to assess the performance of this procedure using the modified Delphi technique and experts in multiple disciplines across the United States. We derived a 22-item checklist designed to assess competency for the completion of ultrasound-guided arthrocentesis, which demonstrated a Cronbach's alpha of 0.89, indicating an excellent degree of internal consistency. Although we were able to demonstrate content validity for this tool, further validity evidence should be acquired after the tool is used and studied in clinical and simulated contexts. © 2017 by the American Institute of Ultrasound in Medicine.

Breast abscess: evidence based management recommendations.

PubMed

Lam, Elaine; Chan, Tiffany; Wiseman, Sam M

2014-07-01

Literature review was carried out and studies reporting on treatment of breast abscesses were critically appraised for quality and their level of evidence using the Strength of Recommendation Taxonomy guidelines, and key recommendations were summarized. Needle aspiration either with or without ultrasound guidance should be employed as first line treatment of breast abscesses. This approach has the potential benefits of: superior cosmesis, shorter healing time, and avoidance of general anaesthesia. Multiple aspiration sessions may be required for cure. Ultrasound-guided percutaneous catheter placement may be considered as an alternative approach for treatment of larger abscesses (>3 cm). Surgical incision and drainage should be considered for first line therapy in large (>5 cm), multiloculated, or long standing abscesses, or if percutaneous drainage is unsuccessful. All patients should be treated concurrently with antibiotics. Patients with recurrent subareolar abscesses and fistulas should be referred for consideration of surgical treatment.

A blanching technique for intradermal injection of the hyaluronic acid Belotero.

PubMed

Micheels, Patrick; Sarazin, Didier; Besse, Stéphanie; Sundaram, Hema; Flynn, Timothy C

2013-10-01

With the proliferation of dermal fillers in the aesthetic workplace have come instructions from various manufacturers regarding dermal placement. Determination of injection needle location in the dermis has in large part been based on physician expertise, product and needle familiarity, and patient-specific skin characteristics. An understanding of the precise depth of dermal structures may help practitioners improve injection specificity. Unlike other dermal fillers that suggest intradermal and deep dermal injection planes, a new hyaluronic acid with a cohesive polydensified matrix may be more appropriate for the superficial dermis because of its structure and its high degree of integration into the dermis. To that end, the authors designed a small study to quantify the depth of the superficial dermis by means of ultrasound and histology. Using ultrasound resources, the authors determined the depths of the epidermis, the dermis, and the reticular dermis in the buttocks of six patients; the authors then extrapolated the depth of the superficial reticular dermis. Histologic studies of two of the patients showed full integration of the product in the reticular dermis. Following determination of injection depths and filler integration, the authors describe a technique ("blanching") for injection of the cohesive polydensified matrix hyaluronic acid into the superficial dermis. At this time, blanching is appropriate only for injection of the cohesive polydensified matrix hyaluronic acid known as Belotero Balance in the United States, although it may have applications for other hyaluronic acid products outside of the United States.

Novel 3-D laparoscopic magnetic ultrasound image guidance for lesion targeting

PubMed Central

Sindram, David; McKillop, Iain H; Martinie, John B; Iannitti, David A

2010-01-01

Objectives: Accurate laparoscopic liver lesion targeting for biopsy or ablation depends on the ability to merge laparoscopic and ultrasound images with proprioceptive instrument positioning, a skill that can be acquired only through extensive experience. The aim of this study was to determine whether using magnetic positional tracking to provide three-dimensional, real-time guidance improves accuracy during laparoscopic needle placement. Methods: Magnetic sensors were embedded into a needle and laparoscopic ultrasound transducer. These sensors interrupted the magnetic fields produced by an electromagnetic field generator, allowing for real-time, 3-D guidance on a stereoscopic monitor. Targets measuring 5 mm were embedded 3–5 cm deep in agar and placed inside a laparoscopic trainer box. Two novices (a college student and an intern) and two experts (hepatopancreatobiliary surgeons) targeted the lesions out of the ultrasound plane using either traditional or 3-D guidance. Results: Each subject targeted 22 lesions, 11 with traditional and 11 with the novel guidance (n = 88). Hit rates of 32% (14/44) and 100% (44/44) were observed with the traditional approach and the 3-D magnetic guidance approach, respectively. The novices were essentially unable to hit the targets using the traditional approach, but did not miss using the novel system. The hit rate of experts improved from 59% (13/22) to 100% (22/22) (P < 0.0001). Conclusions: The novel magnetic 3-D laparoscopic ultrasound guidance results in perfect targeting of 5-mm lesions, even by surgical novices. PMID:21083797

Instrument-mounted displays for reducing cognitive load during surgical navigation.

PubMed

Herrlich, Marc; Tavakol, Parnian; Black, David; Wenig, Dirk; Rieder, Christian; Malaka, Rainer; Kikinis, Ron

2017-09-01

Surgical navigation systems rely on a monitor placed in the operating room to relay information. Optimal monitor placement can be challenging in crowded rooms, and it is often not possible to place the monitor directly beside the situs. The operator must split attention between the navigation system and the situs. We present an approach for needle-based interventions to provide navigational feedback directly on the instrument and close to the situs by mounting a small display onto the needle. By mounting a small and lightweight smartwatch display directly onto the instrument, we are able to provide navigational guidance close to the situs and directly in the operator's field of view, thereby reducing the need to switch the focus of view between the situs and the navigation system. We devise a specific variant of the established crosshair metaphor suitable for the very limited screen space. We conduct an empirical user study comparing our approach to using a monitor and a combination of both. Results from the empirical user study show significant benefits for cognitive load, user preference, and general usability for the instrument-mounted display, while achieving the same level of performance in terms of time and accuracy compared to using a monitor. We successfully demonstrate the feasibility of our approach and potential benefits. With ongoing technological advancements, instrument-mounted displays might complement standard monitor setups for surgical navigation in order to lower cognitive demands and for improved usability of such systems.

Robustness study of the pseudo open-loop controller for multiconjugate adaptive optics.

PubMed

Piatrou, Piotr; Gilles, Luc

2005-02-20

Robustness of the recently proposed "pseudo open-loop control" algorithm against various system errors has been investigated for the representative example of the Gemini-South 8-m telescope multiconjugate adaptive-optics system. The existing model to represent the adaptive-optics system with pseudo open-loop control has been modified to account for misalignments, noise and calibration errors in deformable mirrors, and wave-front sensors. Comparison with the conventional least-squares control model has been done. We show with the aid of both transfer-function pole-placement analysis and Monte Carlo simulations that POLC remains remarkably stable and robust against very large levels of system errors and outperforms in this respect least-squares control. Approximate stability margins as well as performance metrics such as Strehl ratios and rms wave-front residuals averaged over a 1-arc min field of view have been computed for different types and levels of system errors to quantify the expected performance degradation.

PI controller design of a wind turbine: evaluation of the pole-placement method and tuning using constrained optimization

NASA Astrophysics Data System (ADS)

Mirzaei, Mahmood; Tibaldi, Carlo; Hansen, Morten H.

2016-09-01

PI/PID controllers are the most common wind turbine controllers. Normally a first tuning is obtained using methods such as pole-placement or Ziegler-Nichols and then extensive aeroelastic simulations are used to obtain the best tuning in terms of regulation of the outputs and reduction of the loads. In the traditional tuning approaches, the properties of different open loop and closed loop transfer functions of the system are not normally considered. In this paper, an assessment of the pole-placement tuning method is presented based on robustness measures. Then a constrained optimization setup is suggested to automatically tune the wind turbine controller subject to robustness constraints. The properties of the system such as the maximum sensitivity and complementary sensitivity functions (Ms and Mt ), along with some of the responses of the system, are used to investigate the controller performance and formulate the optimization problem. The cost function is the integral absolute error (IAE) of the rotational speed from a disturbance modeled as a step in wind speed. Linearized model of the DTU 10-MW reference wind turbine is obtained using HAWCStab2. Thereafter, the model is reduced with model order reduction. The trade-off curves are given to assess the tunings of the poles- placement method and a constrained optimization problem is solved to find the best tuning.

An assessment of the new generation three-dimensional high definition laparoscopic vision system on surgical skills: a randomized prospective study.

PubMed

Usta, Taner A; Ozkaynak, Aysel; Kovalak, Ebru; Ergul, Erdinc; Naki, M Murat; Kaya, Erdal

2015-08-01

Two-dimensional (2D) view is known to cause practical difficulties for surgeons in conventional laparoscopy. Our goal was to evaluate whether the new-generation, Three-Dimensional Laparoscopic Vision System (3D LVS) provides greater benefit in terms of execution time and error number during the performance of surgical tasks. This study tests the hypothesis that the use of the new generation 3D LVS can significantly improve technical ability on complex laparoscopic tasks in an experimental model. Twenty-four participants (8 experienced, 8 minimally experienced, and 8 inexperienced) were evaluated for 10 different tasks in terms of total execution time and error number. The 4-point lickert scale was used for subjective assessment of the two imaging modalities. All tasks were completed by all participants. Statistically significant difference was determined between 3D and 2D systems in the tasks of bead transfer and drop, suturing, and pick-and-place in the inexperienced group; in the task of passing through two circles with the needle in the minimally experienced group; and in the tasks of bead transfer and drop, suturing and passing through two circles with the needle in the experienced group. Three-dimensional imaging was preferred over 2D in 6 of the 10 subjective criteria questions on 4-point lickert scale. The majority of the tasks were completed in a shorter time using 3D LVS compared to 2D LVS. The subjective Likert-scale ratings from each group also demonstrated a clear preference for 3D LVS. New 3D LVS has the potential to improve the learning curve, and reduce the operating time and error rate during the performances of laparoscopic surgeons. Our results suggest that the new-generation 3D HD LVS will be helpful for surgeons in laparoscopy (Clinical Trial ID: NCT01799577, Protocol ID: BEHGynobs-4).