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Rongqian Yang - One of the best experts on this subject based on the ideXlab platform.

  • HBAI@IJCAI - Intraoperative Accurate Automatic Modeling of Skull Defects with Neuronavigation System
    Human Brain and Artificial Intelligence, 2019
    Co-Authors: Yangjie Xie, Rongqian Yang
    Abstract:

    Reconstruction and repair of skull defects is a very important step for the prognosis of patients in skull base surgery. However, different Surgical approaches will cause different Surgical defects for patients, and it is difficult to accurately reconstruct the three-dimensional (3D) structure of the skull defects for complicated structures approaches such as the trans-eyebrow approach. This study aims at proposing a method with Surgical navigation system for accurately and instantly obtaining the structure of skull defect resulting from craniotomies, which is important for skull repairing. CT scanning is completed and the skull is segmented in the preoperative operation plan. After completing the craniotomy approach operation, the surgeon uses the Surgical Probe to trace along the edge of the skull defect while the navigation system records the three-dimensional coordinates of the Probe tip in real time, and the direction of the main view direction is also recorded. With above information, the structure of defect skull can be reconstructed automatically according to the preoperative segmented skull information. The method using the preoperative image scanning data and intraoperative navigation data to get the structure of the defect skull is accurate and rapid.

  • intraoperative accurate automatic modeling of skull defects with neuronavigation system
    International Joint Conference on Artificial Intelligence, 2019
    Co-Authors: Rongqian Yang
    Abstract:

    Reconstruction and repair of skull defects is a very important step for the prognosis of patients in skull base surgery. However, different Surgical approaches will cause different Surgical defects for patients, and it is difficult to accurately reconstruct the three-dimensional (3D) structure of the skull defects for complicated structures approaches such as the trans-eyebrow approach. This study aims at proposing a method with Surgical navigation system for accurately and instantly obtaining the structure of skull defect resulting from craniotomies, which is important for skull repairing. CT scanning is completed and the skull is segmented in the preoperative operation plan. After completing the craniotomy approach operation, the surgeon uses the Surgical Probe to trace along the edge of the skull defect while the navigation system records the three-dimensional coordinates of the Probe tip in real time, and the direction of the main view direction is also recorded. With above information, the structure of defect skull can be reconstructed automatically according to the preoperative segmented skull information. The method using the preoperative image scanning data and intraoperative navigation data to get the structure of the defect skull is accurate and rapid.

Vivien A. Casagrande - One of the best experts on this subject based on the ideXlab platform.

  • Chronic and acute analysis of optic nerve sheath fenestration with the free electron laser in monkeys
    Lasers in surgery and medicine, 2003
    Co-Authors: Karen M. Joos, Louise A. Mawn, Jin H. Shen, Vivien A. Casagrande
    Abstract:

    Background and Objectives The Amide II wavelength (6.45 μm) produced by the free electron laser (FEL) can efficiently create an optic nerve sheath fenestration in rabbits. We wished to determine if it would be equally successful in macaque monkeys and to determine the histopathologic changes between traditional scissors or knife optic nerve sheath fenestration to FEL fenestration. Study Design/Materials and Methods Optic nerve sheath fenestration was performed using either the FEL (6.45 μm, 30 Hz, 2–3 mJ, 325-μm spot size) through a hollow waveguide Probe in 12 eyes or with a scissors or a knife in 6 eyes. The monkeys survived 1 month with the fellow optic nerve operated acutely just prior to sacrifice. Optic nerves were evaluated histologically. Results Less tissue manipulation was required using the FEL Surgical Probe. Electroretinograms showed minimal or no change. Tissue responses using either method were similar following chronic or acute incisions. Mild upregulation of vimentin and glial fibrillary acid protein (GFAP) was seen in astrocytes adjacent to the fenestration, but no change in S100β was evident. Conclusions The FEL energy at 6.45 μm delivered through a hollow waveguide appears capable of efficiently and safely producing an optic nerve sheath fenestration in monkeys. This innovative Surgical technique should be considered for human use. Lasers Surg. Med. 32:32–41,2003. © 2003 Wiley-Liss, Inc.

  • Acute optic nerve sheath fenestration in humans using the free electron laser (FEL): a case report
    Ophthalmic Technologies XII, 2002
    Co-Authors: Karen Margaret Joos, Jin-hui Shen, Louise A. Mawn, E. Duco Jansen, Vivien A. Casagrande
    Abstract:

    Our previous studies using rabbits and monkeys showed that the Amide II wavelength (6.45 micrometers ) produced by the FEL could efficiently produce an optic nerve sheath fenestration with minimal damage. In order to determine if the technology safely could be applied to human surgery, we used 2 blind human eyes during enucleation to compare the results of producing fenestrations with the FEL or a scissors. FDA and Vanderbilt IRB approvals, and individual patient consents were obtained. The FEL energy was transmitted to a human operating room. After disinsertion of the medial rectus muscle, an optic nerve sheath fenestration (2 mm diameter) was made with either the FEL (6.45 micrometers , 325 micrometers spot size, 30 Hz, 3 mJ) through a hollow waveguide Surgical Probe or with a scissors. The enucleation was then completed. The optic nerve was dissected from the globe and fixed. Specimens were examined histologically. Dural incisions were effective with both methods. FEL energy at 6.45 micrometers can be transmitted to an operating room and delivered to human ocular tissue through a hollow waveguide Surgical Probe. This FEL wavelength can produce an optic nerve sheath fenestration without acute direct damage to the nerve in this case report.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

J.r. Saffer - One of the best experts on this subject based on the ideXlab platform.

  • Performance evaluation of a 64-pixel positron-sensitive Surgical Probe in simulated sentinel lymph node Surgical environment
    IEEE Symposium Conference Record Nuclear Science 2004., 2004
    Co-Authors: R. Wiener, J.r. Saffer, F.m. Newcomer, G.m. Mayers, W. Kononenko, R. Van Berg, J.s. Karp
    Abstract:

    The prototype 64-pixel positron-sensitive Surgical Probe has been repackaged in preparation for moving the Probe into clinical Surgical environment The Probe detector front opening is covered with a 25 /spl mu/m thick aluminum foil, which makes the Probe a both light-tight and sterilizable system. As previously reported, the Probe consists of a dual-layer detector and a multi-anode PMT (Hamamatsu H7546). The first layer consists of an 8/spl times/8 array of thin plastic scintillators, which is 1:1 optically coupled to an 8/spl times/8 array of 2/spl times/2/spl times/10 mm/sup 3/ GSO crystals. Each pixel element is optically isolated using CaCO/sub 3/ sheet reflectors. With this dual-layer design and customized 64 channels of electronics (with FPGA), a valid event is a signal in the plastic layer characterized with an overshoot by the pulse-shaping circuit, in coincidence with an annihilation 511 keV gamma in the GSO layer, selected by an energy threshold on the PMT summed dynode signal. Operating this repackaged Probe system outside of the black box, the new measurements show that the 64-pixel Probe has a sensitivity of /spl sim/36 cps/pixel per /spl mu/Ci/cc using optimal signal selection criteria, which is 80% higher than the sensitivity of the previous system which did not have a foil covering. The repackaged Probe system is also confirmed to have similar spatial resolution and good lesion identification ability as previous system. For example, it is able to identify in 10 seconds a /spl sim/2.8 mm lesion with a contrast of /spl sim/2.6 at the presence of both 511 keV gamma (tumor to background ratio: 7:1) and 140 keV gamma background (tumor to background ratio: 1:16).

  • Performance evaluation of a 64-pixel Surgical Probe for FDG imaging
    2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515), 2003
    Co-Authors: J.r. Saffer, F.m. Newcomer, J.s. Karp, G.m. Mayers, W. Kononenko, N.s. Lockyer
    Abstract:

    We report on the performance of a completed 64-pixel positron-sensitive Surgical Probe using wall-less sphere sources in preparation for clinical testing. The method of making volumetric positron sources by uniformly mixing /sup 18/F with beeswax through a chemical procedure enables us to evaluate the performance of the Probe in a more realistic environment. As previously reported, the Probe consists of a dual-layer detector and a multianode PMT (Hamamatsu H7546). The first layer consists of an 8/spl times/8 array of thin plastic scintillators, which is 1:1 optically coupled to an 8/spl times/8 array of 2/spl times/ 2/spl times/10 mm/sup 3/ GSO crystals. Each pixel element is optically isolated using CaCO/sub 3/ reflectors. With this dual-layer design and customized 64 channels of electronics (with FPGA), a valid event is a signal in the plastic layer characterized with an overshoot by the pulse-shaping circuit, in coincidence with an annihilation 511 keV gamma in the GSO layer, selected by an energy threshold on the PMT summed dynode signal. Now using wall-less sphere sources we more completely characterize the Probe's performance based on a more accurate simulation of the sentinel lymph node Surgical environment. The new measurements show that the 64-pixel Probe has a sensitivity of /spl sim/20 cps/pixel per /spl mu/Ci/cc using optimal signal selection criteria. The Probe is able to identify in 10 seconds a /spl sim/4 mm lesion with a true-to-background ratio of /spl sim/3 at a tumor uptake ratio of /spl sim/8:1.

  • A 64-pixel positron-sensitive Surgical Probe
    2002 IEEE Nuclear Science Symposium Conference Record, 2002
    Co-Authors: J.r. Saffer, F.m. Newcomer, J.s. Karp, G.m. Mayers, W. Kononenko, N.s. Lockyer
    Abstract:

    We report on the continued development of a 64-pixel positron-sensitive Surgical Probe with a dual-layer detector and a multi-anode PMT. An 8 /spl times/ 8 array of thin plastic scintillators in the first layer detects positrons and a matched GSO crystal array in the second layer detects annihilation 511 keV gammas, which are required to be in coincidence with the detected positrons. Also, the 64 PMT anode signals are differentiated and an overshoot threshold is applied to separate the fast decay plastic anode signals from the slower GSO anode signals. Finally, an energy threshold is applied to the summed anode signal to distinguish 511 keV gammas from the 140 keV gammas commonly used in sentinel lymph node (SLN) surgery. Previously we reported on how these signal selection criteria were individually tested and optimized based on 9 channels of prototype electronics. Currently the electronics have been upgraded to Xilinx/spl reg/ programmable components, allowing on-the-fly alteration of signal selection criteria, and all 64 channels are operational. Initial measurements of the complete 64-pixel Probe were conducted using /sup 18/F-FDG positron sources and /sup 18/F-FDG and /sup 99m/Tc phantoms (background 511 keV and 140 keV gammas), simulating lesions in the SLN surgery environment. The average positron sensitivity is measured to be 3.0-7.0 kcps//spl mu/Ci at different signal selection criteria. The lower bound on sensitivity corresponds to settings optimized for high image resolution and high background rejection ability. The upper bound on sensitivity corresponds to settings optimized for high sensitivity at the cost of lower image resolution and lower background rejection ability. The measured true-to-background contrast in the presence of clinically observed levels of 511 keV and 140 keV background gammas is /spl sim/3:1 for a tumor-to-background uptake ratio of 5:1. Performance measurements of the complete 64-pixel Probe including sensitivity, true-to-background ratio, and the pixel separation ability are presented.

  • Performance of a dual-layer positron-sensitive Surgical Probe
    2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310), 2001
    Co-Authors: J.r. Saffer, N.s. Lockyer, F.m. Newcomer, J.s. Karp, W. Kononenko
    Abstract:

    A positron-sensitive Surgical Probe is being built based on a multi-anode PMT and a dual-layer detector, which consists of an 8/spl times/8 array of thin plastic scintillators and a matched GSO crystal array. Our Probe uses three selection criteria to identify positrons and suppress background gammas, including annihilation 511 keV gammas. First an energy threshold was applied on the plastic signals; next a second energy threshold was applied on the PMT sum signal; finally, a coincidence technique between the positrons and the annihilation 511 keV gammas was applied. These selection criteria were individually tested and optimized, and have been implemented with 9 channels of electronics. Experiments were conducted using phantoms with /sup 18/F-FDG and /sup 99m/Tc, commonly used in sentinel lymph node (SLN) surgery. Measurements based on the 9-channel electronics indicate that the sensitivity of the 9-channel Probe to positrons from /sup 18/F-FDG is /spl sim/69-152 cps/kBq (2.5-5.6 kcps//spl mu/LCi) at different signal selection criteria The final 64-channel Probe is expected to have /spl sim/40% higher positron sensitivity. The pixel separation is /spl sim/3.2 in terms of the peak to valley ratio. The second layer of the detector gives superior rejection power for 140 keV gammas. The true to false positron count ratio in the presence of 511 keV and 140 keV background gammas is expected to be high (>10) at a tumor to background ratio of 10:1.

  • Design and performance of a portable positron-sensitive Surgical Probe
    2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149), 2000
    Co-Authors: J.r. Saffer, N.s. Lockyer, F.m. Newcomer, J.s. Karp, W. Konenenko
    Abstract:

    Reports the design and performance of a portable positron-sensitive Surgical Probe. The Probe is designed to be sensitive to positrons and insensitive to background gammas including 511 keV. The Probe consists of a multi-mode PMT and an 8/spl times/8 array of thin 2 mm /spl times/2 mm plastic scintillators coupled 1:1 to GSO crystals. The Probe uses three selection criteria to identify positrons. An energy threshold on the plastic signals reduces the false positron signals in the plastic due to background gammas: a second energy threshold on the PMT sum signal greatly reduces background gammas in the GSO. Finally, a timing window accepts only 511 keV gammas from the GSO that arrive within 15 ns of the plastic signals, reducing accidental coincidences to a negligible level. The first application being investigated is sentinel lymph node (SLN) surgery, to identify in real-time the location of SLNs in the axilla with /sup 18/F-FDG uptake, which may indicate metastasis. The authors' simulations and measurements suggest that the Probe's signal to background ratio in this situation will be high. Preliminary results on the performance of the Probe are presented.

Randy E. Ellis - One of the best experts on this subject based on the ideXlab platform.

  • AN INTEGRATED CALIBRATOR AND VERIFICATION TOOL FOR ELECTROMAGNETIC NAVIGATION OF INTRA-OPERATIVE COMPUTED TOMOGRAPHY
    Journal of Bone and Joint Surgery-british Volume, 2016
    Co-Authors: B J Rasquinha, Andrew W. L. Dickinson, Randy E. Ellis
    Abstract:

    Surgical navigation requires an accurate, stable transformation between the tracking system and reference images. This study was the design and evaluation of an additively manufactured calibrator with an integrated verification tool, used to register cone-beam computed tomography (CBCT) image volume to electromagnetic (EM) tracking. An Aurora EM system was used to track both the calibrator and a Surgical Probe. Intraoperative CBCT images were acquired with a GE Innova 4100 scanner. The calibrator incorporated 7 tantalum beads, a 6DOF EM sensor, and 7 through-holes for calibrator verification. The calibrator was characterised using the beads and averaged EM reading in 10 poses. Target Registration Error (TRE) estimation used a device with 14 beads and 18 through-holes. For verification, the Probe was placed in each path and the axis and tip location measured relative to the calibrator. This verification task took about 45s. Axial error was the angle between the Probed paths and designed axes; translation error was the shortest distance between these lines. The translation TRE was 3.14±0.96 mm and the angular TRE was 1.7±0.7 degrees, which is consistent with published EM evaluations. The validation axes had an inter-line distance of 0.9±0.78 mm and an axial difference of 1.1±0.7 degrees. The verification errors were smaller than TRE because of the different mathematical formulation. Although the verification calculation was not exactly a tracking error, it provided an alternative quantitative assessment of registration accuracy. This integrated intra-operative registration verification minimises modifications to the Surgical workflow and these results demonstrated highly accurate orientation tracking in a Surgical environment.

  • MICCAI (2) - A Tactile Magnification Instrument for Minimally Invasive Surgery
    Medical Image Computing and Computer-Assisted Intervention – MICCAI 2004, 2004
    Co-Authors: Vincent Hayward, Randy E. Ellis
    Abstract:

    The MicroTactus is a family of instruments that we have designed to detect signals arising from the interaction of a tip with soft or hard objects and to magnify them for haptic and auditory reproduction. We constructed an enhanced arthroscopic Surgical Probe and tested it in detecting surface defects of a cartilage-like material. Elastomeric samples were cut at different depths and mixed with blank samples. Subjects were asked to detect the cuts under four conditions: no amplification, with haptic feedback, with sound feedback, and with passive touch. We found that both haptic and auditory feedback significantly improved detection performance, which demonstrated that an enhanced arthroscopic Probe provided useful information for the detection of small cuts in tissue-like materials.

Hatice Durak - One of the best experts on this subject based on the ideXlab platform.

  • Exposure of Surgical Staff to Radiation During Surgical Probe Applications in Breast Cancer
    Journal of Breast Cancer, 2009
    Co-Authors: Recep Bekiş, Pinar Çelik, Banu Uysal, Mehmet Ali Kocdor, Ali İbrahim Sevinç, Serdar Saydam, Omer Harmancioglu, Hatice Durak
    Abstract:

    Purpose: The aim of study was to determine the level of the radiation exposure of Surgical staff during Surgical Probe applications in breast cancer. Methods: Three operations of a sentinel lymph node biopsy were randomly selected. Spaced circles (50 cm apart) were drawn surrounding the operation bed on the floor. Tc-99m nanocolloid was injected peritumorally and intradermally into a patient. The radiation dose was measured with a GeigerMueller counter placed according to the drawn circles at distances of 50-200 cm from the side of patient’s head and bilateral chest while the patient lay on the operation bed. All of the Surgical procedures were recorded with a video camera and were monitored. Results: The whole body dose to the senior surgeon was calculated as 2.00-4.70 μ Sv which means that a senior surgeon can perform 212-500 procedures per year to reach the annual International Commission on Radiological Protection radiation dose limit for a member of the public. Conclusion: We concluded that radiation risk to the Surgical staff is low from sentinel node detection with the use of radiocolloids.

  • Exposure of Surgical staff in Surgical Probe applications in radioguided parathyroidectomy
    European Archives of Oto-Rhino-Laryngology, 2008
    Co-Authors: Recep Bekiş, Pinar Çelik, Banu Uysal, Mehmet Ali Kocdor, Serdar Saydam, Omer Harmancioglu, Koray Atila, Hatice Durak
    Abstract:

    The aim of this study is to calculate the exposure of Surgical staff during radioguided parathyroidectomy. Two parathyroidectomy operations on patients with parathyroid adenoma were selected. Fifty-centimeter spaced circles were drawn surrounding the operation bed on the floor of the operation room. During the operation, radiation dose was measured according to the drawn circles at distances of 50–200 cm from the side of patient’s head, bilateral neck and abdomen while the patient lied on the operation bed. All the operations were recorded throughout with a video camera. Three physicians watched all records. The time spent at each distance for every staff during the operation was recorded. Whole body dose to senior surgeon was calculated as 8.78–11.00 μSv which means that a senior surgeon can perform 91–114 procedures per year to reach the annual International Commission on Radiological Protection (ICRP) radiation dose limit for a member of the public. We concluded that radiation risk to the Surgical staff is low from radioguided parathyroidectomy.