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Sample records for optically-guided frameless linac-based

  1. Adjuvant therapy after resection of brain metastases. Frameless image-guided LINAC-based radiosurgery and stereotactic hypofractionated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Broemme, J.; Aebersold, D.M.; Pica, A. [Bern Univ., Bern Univ. Hospital (Switzerland). Dept. of Radiation Oncology; Abu-Isa, J.; Beck, J.; Raabe, A. [Bern Univ., Bern Univ. Hospital (Switzerland). Neurosurgery; Kottke, R.; Wiest, R. [Bern Univ., Bern Univ. Hospital (Switzerland). Neuroradiology; Malthaner, M.; Schmidhalter, D. [Bern Univ., Bern Univ. Hospital (Switzerland). Div. of Medical Radiation Physics

    2013-09-15

    Background: Tumor bed stereotactic radiosurgery (SRS) after resection of brain metastases is a new strategy to delay or avoid whole-brain irradiation (WBRT) and its associated toxicities. This retrospective study analyzes results of frameless image-guided linear accelerator (LINAC)-based SRS and stereotactic hypofractionated radiotherapy (SHRT) as adjuvant treatment without WBRT. Materials and methods: Between March 2009 and February 2012, 44 resection cavities in 42 patients were treated with SRS (23 cavities) or SHRT (21 cavities). All treatments were delivered using a stereotactic LINAC. All cavities were expanded by {>=} 2 mm in all directions to create the clinical target volume (CTV). Results: The median planning target volume (PTV) for SRS was 11.1 cm{sup 3}. The median dose prescribed to the PTV margin for SRS was 17 Gy. Median PTV for SHRT was 22.3 cm{sup 3}. The fractionation schemes applied were: 4 fractions of 6 Gy (5 patients), 6 fractions of 4 Gy (6 patients) and 10 fractions of 4 Gy (10 patients). Median follow-up was 9.6 months. Local control (LC) rates after 6 and 12 months were 91 and 77 %, respectively. No statistically significant differences in LC rates between SRS and SHRT treatments were observed. Distant brain control (DBC) rates at 6 and 12 months were 61 and 33 %, respectively. Overall survival (OS) at 6 and 12 months was 87 and 63.5 %, respectively, with a median OS of 15.9 months. One patient treated by SRS showed symptoms of radionecrosis, which was confirmed histologically. Conclusion: Frameless image-guided LINAC-based adjuvant SRS and SHRT are effective and well tolerated local treatment strategies after resection of brain metastases in patients with oligometastatic disease. (orig.)

  2. Importance of CBCT setup verification for optical-guided frameless radiosurgery.

    Science.gov (United States)

    Fu, Lei; Perera, Harold; Ying, Xiao; Yu, Yan

    2014-05-08

    The purpose of this study is to quantify the discrepancy between optical guidance platform (OGP) frameless localization system (Varian) and Trilogy on-board imaging (OBI) system (Varian) for setting up phantom and stereotactic radiosurgery (SRS) patient; and to determine whether cone-beam CT (CBCT) is necessary for OGP patient setup, and compare CBCT and orthogonal kV-kV in term of their verification capability. Three different phantoms were used in the study: a custom-made phantom, a Penta-Guide phantom, and a RANDO phantom. Five patients using both OGP and CBCT setup and 14 patients using CBCT setup alone were analyzed. One patient who had big couch shifts discrepancy between OGP and CBCT was selected for further investigation. Same patient's CBCT and planning CT were fused. A RANDO phantom simulation experiment was performed using OGP setup with both CBCT and orthogonal kV-kV verification. For all of three phantom experiments, the shifts performed by CBCT beam and orthogonal kV-kV were all within 1 mm. Among five SRS patients using OGP setup, three had 3D couch corrections more than 3 mm. The image fusion of CBCT and planning CT clearly illustrated a tilt of bite-block in a patient's mouth. For 14 SRS patients using CBCT-guided setup, overall 3D correction was 3.3 ± 1.5 mm. RANDO phantom experiment demonstrated how a tilted bite-block caused isocenter shift. CBCT-calculated shifts are the same as expected, but kV-kV results differed by 1-2 mm if the initial head position is tilted. The bite-block tilting in patient's mouth is a major reason for the cause of positioning error for OGP frameless SRS setup. CBCT verification is necessary. CBCT provides more accurate couch corrections than orthogonal kV-kV when head was tilted. OGP is useful for detecting patient movement, but it does not necessarily imply that the isocenter has moved.

  3. Three independent one-dimensional margins for single-fraction frameless stereotactic radiosurgery brain cases using CBCT

    CERN Document Server

    Zhang, Qinghui; Burman, Chandra; Song, Yulin; Zhang, Mutian

    2013-01-01

    Setting a proper margin is crucial for not only delivering the required radiation dose to a target volume, but also reducing the unnecessary radiation to the adjacent organs at risk. This study investigated the independent one-dimensional symmetric and asymmetric margins between the clinical target volume (CTV) and the planning target volume (PTV) for linac-based single-fraction frameless stereotactic radiosurgery (SRS).

  4. SU-E-T-536: LINAC-Based Single Isocenter Frameless SRT for Brain Metastases

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    Liu, B; Zhang, L; Rigor, N; Kim, J [City of Hope Foundation, CA (United States)

    2015-06-15

    Purpose: Single-isocenter Stereotactic Radiotherapy of multiple brain metastases with Varian 21 IX LINAC, using Aktina Pinpoint system for patient setup. Methods: In 2014, five single-isocenter RapidArc SRT plans were delivered to five patients with 2 to 8 brain metastases using Varian 21 IX. Aktina Pinpoint system was used for setup and 2mm PTV margin were used. CBCT was acquired before and after the beam delivery. The prescription is 2100 cGy in 3 fractions. Eclipse planning system was used for treatment planning. Depending on the number of metastases and their locations, 1 to 5 coplanar or non coplanar arcs were used. Typically, 2 or 3 arcs are used. IMRT QAs were performed by comparing an A1SL ion chamber point dose measurement in solid water phantom to point dose of the plan; also, based on EPID measurement, 3D spatial dose was calculated using DosimetryCheck software package from MathResolutions Inc. The EPID system has an active area of 40cm by 30cm with 1024 by 768 photodiodes, which corresponds to a resolution of 0.4mm by 0.4mm pixel dimension. Results: for all the plans, at least 95% PTV coverage was achieved for full prescription dose, with plan normalization > 75%. RTOG conformity indices are less than 1.1 and Paddick gradient indices are less than 4.5. The distance from prescription IDL to 50% IDL increases as the number of metastases increases, and it ranges from 0.6mm to 0.8mm. Treatment time varies from 10mins to 30mins, depending on the number of arcs and if the arcs are coplanar. IMRT QA shows that the ion chamber measurement agree with the eclipse calculation within 3%, and 95% of the points passed Gamma, using 3% dose difference and 3mm DTA Conclusion: High quality single isocenter RapidArc SRT plan can be optimized and accurately delivered using Eclipse and Varian 21IX.

  5. Frameless image-guided neurosurgery in motion

    NARCIS (Netherlands)

    Woerdeman, P.A.

    2008-01-01

    The general objective of this thesis was the enhancement of image-guidance system use by optimizing “man-machine” interaction in frameless image-guided neurosurgery. Part I. The application of frameless stereotaxy in the neurosurgical practice We aimed to compare three patient-to-image registration

  6. Treatment of intracranial meningioma with linac based radiosurgery

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    Kay, Chul Seung; Yoon, Sei Chul; Chung, Su Mi; Ryu, Mi Ryung; Kim, Yeon Sil; Suh, Tae Suk; Choi, Kyu Ho; Son, Byung Chul; Kim, Moon Chan [College of Medicine, Catholic Univ., Seoul (Korea, Republic of)

    2001-03-01

    To evaluate the role of linac based radiosurgery (RS) in the treatment of meningiomas, we retrospectively analyzed the results of clinical and follow up CT/MRI studies. From the 1988 July to 1998 April, twenty patients of meningioma had been treated with 6 MV linear accelerator based radiosurgery. Of the 20 patients, four (20%) were male and 16 (80%) were female. Mean age was 51 years old (22-78 years old). Majority of intracranial location of tumor for RS were parasagittal and sphenoid wing area. RS was done for primary treatment in 6 (30%), postoperative residual lesions in 11 (55%) and regrowth after surgery in 3 (15%). Mean tumor volume was 5.72 cm{sup 3} (0.78 - 15.1 cm{sup 3}) and secondary collimator size was 2.04 cm (1-3 cm). The periphery of tumor margin was prescribed with the mean dose of 19.6 Gy (9-30 Gy) which was 40-90% of the tumor center dose. The follow up duration ranged from 2.5 to 109 months (median 53 months). Annual CT/MRI scan was checked. By the follow up imaging studies, the tumor volume was reduced in 5 cases (25%), arrested growth in 14 cases (70%), and increased size in 1 case (15%). Among these responsive and stable 19 patients by imaging studies, there showed loss of contrast enhancement after CT/MRI in four patients. In clinical response, nine (45%) patients were considered improved condition, 10 (50%) patients were stable and one (5%) was worsened to be operated. This partly resulted in necrosis after surgery.The overall control rate of meningiomas with linac based RS was 95% by both imaging follow-up and clinical evaluation. With this results, linac based RS is considered safe and effective treatment method for meningioma.

  7. Status of the Linac based positron source at Saclay

    CERN Document Server

    Rey, J -M; Debu, P; Dzitko, H; Hardy, P; Liszkay, L; Lotrus, P; Muranaka, T; Noel, C; Perez, P; Pierret, O; Ruiz, N; Sacquin, Y

    2013-01-01

    Low energy positron beams are of major interest for fundamental science and materials science. IRFU has developed and built a slow positron source based on a compact, low energy (4.3 MeV) electron linac. The linac-based source will provide positrons for a magnetic storage trap and represents the first step of the GBAR experiment (Gravitational Behavior of Antimatter in Rest) recently approved by CERN for an installation in the Antiproton Decelerator hall. The installation built in Saclay will be described with its main characteristics. The ultimate target of the GBAR experiment will be briefly presented as well as the foreseen development of an industrial positron source dedicated for materials science laboratories.

  8. [Frameless stereotactic biopsy: diagnostic yield and complications].

    Science.gov (United States)

    Castle, Maria; Nájera, Edinson; Samprón, Nicolas; Bollar, Alicia; Urreta, Iratxe; Urculo, Enrique

    2014-01-01

    The aim of this study was to evaluate the variables that could modify the diagnostic yield of frameless stereotactic biopsy, as well as its complications. This was a retrospective study of frameless stereotactic biopsies carried out between July 2008 and December 2011 at Donostia University Hospital. The variables studied were size, distance to the cortex, contrast uptake and location. A total of 70 patients were included (75 biopsies); 39 males and 31 females with an age range between 39 and 83 years. The total diagnostic yield in our series was 97.1%. For lesions >19mm, the technique offered a sensitivity of 95.2% (95% CI: 86.9-98.4) and specificity of 57.1% (95% CI: 25.0-84.2). The yield was lower for lesions within 17mm of the cortex: sensitivity of 74.6% (95% CI: 62.1-84.7) and specificity of 71.4% (95% CI: 29.0-96.3). Seven (10%) patients developed complications after the first biopsy and none after the second. The diagnostic yield was lower for lesions less than 2cm in size and located superficially. In this series we did not observe an increased rate of complications after a second biopsy. Copyright © 2013 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  9. Radiosurgery with linac based photon knife in cerebral arteriovenous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Hee; Choi, Tae Jin [College of Medicine, Keimyung Univ., Taegu (Korea, Republic of)

    2003-03-01

    The purpose of this study was to analyze the effect of a linear accelerator based Photon Knife Radiosurgery System developed by the staff of Keimyung University Dongsan Medical Center for the treatment of cerebral arteriovenous malformation. Between December 1993 and October 2000, 30 patients with cerebral arteriovenous malformation (AVM) were treated with the Linac based Photon Knife Radiosurgery System in the Department of Therapeutic Radiology at Keimyung University Dongsan Medical Center. The median age was 34, ranging from 7 to 63 years, with a 2: 1 male to female ratio. The locations of the AVM nidi were the frontal lobe (motor cortex), parietal lobe, and the thalamus, in that order. The diameters of the AVM nidi ranged 1.2 to 5.5 cm with a mean of 2.9 cm, and target volumes of between 0.5 and 20.6 cc, with a mean of 6.8 cc. The majority of patients received radiation doses of between 1,500 and 2,500 cGy, with a mean of 2,000 cGy, at 8O% the isodose line. Twenty-five patients were treated with one isocenter, 4 with two, and 1 with four. The follow-up radiological evaluations were performed with cranial computed tomogram (CT) or MRI between 6 month and one year interval, and if the AVM nidus had completely disappeared in the CT or MRI, we confirmed this was a complete obliteration, with a cerebral or magnetic resonance angiogram (MRA). The median follow-up period was 39 months with a range of 10 to 103 months. Twenty patients were radiologically followed up for over 20 months, with complete obliteration observed in 14 (70%). According to the maximal diameter. all four of the small AVM (<2 cm) completely obliterated, 8 of the 10 patients with a medium A VM (2 - 3 cm) showed a complete obliteration, and two showed partial obliteration, Among the patients with a large AVM (>3 cm), only one showed complete obliteration, and 5 showed partial obliteration, but 3 of these underwent further radiosurgery 3 years later. One who followed up for 20 months following

  10. Linac based photofission inspection system employing novel detection concepts

    Science.gov (United States)

    Stevenson, John; Gozani, Tsahi; Elsalim, Mashal; Condron, Cathie; Brown, Craig

    2011-10-01

    Rapiscan Systems is developing a LINAC based cargo inspection system for detection of special nuclear material (SNM) in cargo containers. The system, called Photofission Based Alarm Resolution (PBAR) is being developed under a DHD/DNDO Advanced Technology Demonstration (ATD) program. The PBAR system is based on the Rapiscan Eagle P9000 X-ray system, which is a portal system with a commercial 9 MeV LINAC X-ray source. For the purposes of the DNDO ATD program, a conveyor system was installed in the portal to allow scanning and precise positioning of 20 ft ISO cargo containers. The system uses a two step inspection process. In the first step, the basic scan, the container is quickly and completely inspected using two independent radiography arrays: the conventional primary array with high spatial resolution and a lower resolution spectroscopic array employing the novel Z-Spec method. The primary array uses cadmium tungstate (CdWO 4) detectors with conventional current mode readouts using photodiodes. The Z-Spec array uses small plastic scintillators capable of performing very fast (up to 10 8 cps) gamma-ray spectroscopy. The two radiography arrays are used to locate high-Z objects in the image such as lead, tungsten, uranium, which could be potential shielding materials as well as SNM itself. In the current system, the Z-Spec works by measuring the energy spectrum of transmitted X-rays. For high-Z materials the higher end of the energy spectrum is more attenuated than for low-Z materials and thus has a lower mean energy and a narrower width than low- and medium-Z materials. The second step in the inspection process is the direct scan or alarm clearing scan. In this step, areas of the container image, which were identified as high Z, are re-inspected. This is done by precisely repositioning the container to the location of the high-Z object and performing a stationary irradiation of the area with X-ray beam. Since there are a large number of photons in the 9 MV

  11. Frameless image-guided radiosurgery for trigeminal neuralgia

    Science.gov (United States)

    Shields, Lisa B. E.; Shanks, Todd S.; Shearer, Andrew J.; Shelton, Lauren A.; Shelton, Brent J.; Howe, Jonathan; Coons, James M.; Plato, Brian; Spalding, Aaron C.

    2017-01-01

    Background: Frameless image-guided radiosurgery (IGRS) is a safe and effective noninvasive treatment for trigeminal neuralgia (TN). This study evaluates the use of frameless IGRS to treat patients with refractory TN. Methods: We reviewed the records of 20 patients diagnosed with TN who underwent frameless IGRS treatments between March 2012 and December 2013. Facial pain was graded using the Barrow Neurological Institute (BNI) scoring system. The initial setup uncertainty from simulation to treatment and the patient intrafraction uncertainty were measured. The median follow-up was 32 months. Results: All patients’ pain was BNI Grade IV or V before the frameless IGRS treatment. The mean intrafraction shift was 0.43 mm (0.28–0.76 mm), and the maximum intrafraction shift was 0.95 mm (0.53–1.99 mm). At last follow-up, 8 (40%) patients no longer required medications (BNI 1 or 2), 11 (55%) patients were pain free but required medication (BNI 3), and 1 (5%) patient had no pain relief (BNI 5). Patients who did not have prior surgery had a higher odds ratio for pain relief compared to patients who had prior surgery (14.9, P = 0.0408). Conclusions: Frameless IGRS provides comparable dosimetric and clinical outcomes to frame-based SRS in a noninvasive fashion for patients with medically refractory TN. PMID:28607821

  12. A Cherenkov radiator for FEL-synchronized VUV-pulses at a linac-based FEL

    NARCIS (Netherlands)

    Goloviznin, V. V.; Oepts, D.; van der Wiel, M. J.

    1997-01-01

    A possible way to carry out two-color IR+VUV pump-probe experiments at linac-based FELs is proposed. The idea is to supply an FEL facility with a gas cell filled with helium or hydrogen, so that the electron beam, upon passage through the undulator, could be used to generate ultraviolet Cherenkov

  13. Present and next steps of the JAERI superconducting rf linac based FEL program

    Energy Technology Data Exchange (ETDEWEB)

    Minehara, E.J.; Yamauchi, T.; Sugimoto, M. [FEL Laboratory at Tokai, Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (JP)] (and others)

    2000-03-01

    The JAERI superconducting rf linac based FEL has successfully been lased to produce a 0.3 kW FEL light and 100 kW or larger electron beam output in quasi continuous wave operation in 1999. The 1 kW class output as our present program goal will be achieved to improve the optical out coupling method in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. As our next 5 year program goal is the 100 kW class FEL light and a few tens MW class electron beam output in average, quasi continuous wave operation of the light and electron beam will be planned in the JAERI superconducting rf linac based FEL facility. Conceptual design options needed for such a very high power operation and shorter wavelength light sources will be discussed to improve and to upgrade the exciting facility. (author)

  14. Bonded Bracket Assmebly for Frameless Solar Panels

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Todd [Rayce Americas, Auburn Hills, MI (United States); Jackson, Nick [Rayce Americas, Auburn Hills, MI (United States); Dupont, Luc [ARaymond Tinnerman Industries, Inc., Brunswick, OH (United States); Moser, Jeff [ARaymond Tinnerman Industries, Inc., Brunswick, OH (United States)

    2013-01-30

    that would be bonded to frameless PV modules for commercial rooftop installations; 2) The development of a composite pultruded rail to replace traditional racking materials; 3) In partnership with a roofing company, pilot the certification of a commercial roof to be solar panel compliant, eliminating the need for structural analysis and government oversight resulting in significantly decreased permitting costs; and 4) Reduce the sum of all cost impacts in topic #2 from a baseline total of $2.05/watt to $.34/watt.

  15. Safety and Efficacy of Frameless Stereotactic Brain Biopsy Techniques

    Institute of Scientific and Technical Information of China (English)

    Qiu-jian Zhang; Wen-hao Wang; Xiang-pin Wei; Yi-gang Yu

    2013-01-01

    Objective To explore the safety and efficacy of frameless stereotactic brain biopsy.MethodsDiagnosticaccuracy was calculatedby comparing biopsy diagnosis with definitive pathology in 62 patients who underwent frameless stereotactic brain biopsy between January 2008 and December 2010in Xiamen University Southeast Hospital. Preoperative characteristics and histological diagnosis werereviewed and then information was analysed to identify factors associated with the biopsy not yielding a diagnosis and complications.ResultsDiagnostic yield was 93.5%. No differences were found between pathological diagnosis andfrozen pathological diagnosis. The most common lesions were astrocytic lesions, included 16 cases of low-grade glioma and 12 cases of malignant glioma.Remote hemorrhage, metastasis, and lymphoma werefollowing in incidence. Multiple brain lesions were found in 17 cases (27.4%). Eleven cases were frontal lesions (17.7%), 8 were frontotemporal (12.9%), 6 were frontoparietal (9.7%), and 5 each were temporal,parietal, and parietotemporal lesions (8.1%).Postoperative complications occurred in 21.0% of the patients after biopsies,including 10 haemorrhages (16.1%) and 3 temporary neurological deficits (1 epilepsy, 1headache, and 1 partial hemiparesis). No patient required operation for hematoma evacuation.Conclusion Frameless stereotactic biopsy is an effective and safetechnique for histologic diagnosis of brain lesions, particularly for multifocal and frontal lesions.

  16. Long-term results of LINAC-based stereotactic radiosurgery for acoustic neuroma: The Greek experience

    Directory of Open Access Journals (Sweden)

    Kalogeridi Maria-Aggeliki

    2009-01-01

    Full Text Available Purpose: To estimate the value of LINAC-based stereotactic radiosurgery (SRS for the long-term local control of unilateral acoustic neuromas. Materials and Methods: Twenty patients (median age 66; range 57-80 years with unilateral acoustic neuroma underwent LINAC-based SRS from May 2000 through June 2004 with a dose of 11-12 Gy. The follow-up period ranged from 36 to 84 months (median follow-up period: 55 months. Before SRS none of the patients had useful hearing. The follow-up consisted of repeat imaging studies and clinical examination for assessment of facial and trigeminal nerve function at 6-month intervals for the first year and yearly thereafter. Results: Eleven tumors (58% decreased in size and eight (42% remained stable. One tumor showed a minor increase in size on the MRI done 6 months after SRS in comparison with the pretreatment MRI; however, a subsequent decrease was noticed on the next radiographic assessment and the tumor remained stable from then on. None of the tumors increased in size in the long-term follow-up, thus giving an overall growth control of 100% for the patients in this study. None of the patients had useful hearing before SRS, so hearing level was not assessed during follow-up. No patient developed new, permanent facial or trigeminal neuropathy. Conclusion: LINAC-based SRS with 11-12 Gy provides excellent tumor control in acoustic neuroma and has low toxicity even after long-term follow-up.

  17. Fast-MICP for frameless image-guided surgery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jiann-Der; Huang, Chung-Hsien; Wang, Sheng-Ta; Lin, Chung-Wei; Lee, Shin-Tseng [Department of Electrical Engineering, Chang Gung University, Tao-Yuan 333, Taiwan (China); Department of Medical Mechatronics, Chang Gung University, Tao-Yuan 333, Taiwan (China); Department of Neurosurgery and Medical Augmented Reality Research Center, Chang Gung Memorial Hospital, No. 199, Tunghwa Rd., Taipei 105, Taiwan (China)

    2010-09-15

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

  18. Simulations of mode reduction with an intracavity etalon in an RF-Linac based FEL

    Science.gov (United States)

    Oepts, D.; van der Meer, A. F. G.; Best, R. W. B.; van Amersfoort, P. W.; Colson, W. B.

    1989-12-01

    Coherence between successive light pulses from an rf-linac based FEL can be induced by means of an intracavity interferometric element such as an etalon. This considerably reduces the number of active cavity modes and facilitates the selection of a single narrow line from the laser output. Computer simulations for the operation of an etalon in the FELIX design are shown. The model based on the wave equation driven by single particles has been applied in simulations using a small number (up to six) of initially independent pulses. The case with 40 separate pulses in the cavity is treated with a simpler model. The simulations show that a low-finesse etalon suffices to obtain a large degree of coherence between successive pulses. Saturated operation in a reduced number of modes, but with the same total power, is attained with a delay of a few microseconds.

  19. JAERI superconducting RF linac-based free-electron laser-facility

    CERN Document Server

    Minehara, E J; Nagai, R; Kikuzawa, N; Sugimoto, M; Hajima, R; Shizuma, T; Yamauchi, T; Nishimori, N

    2000-01-01

    Recently, the JAERI superconducting RF linac based FEL has been successfully lased to produce 0.36 kW of FEL light using a 100 kW electron beam in quasi-continuous wave operation. A 1 kW class laser is our present program goal, and will be achieved by improving the optical out coupling in the FEL optical resonator, the electron gun, and the electron beam optics in the JAERI FEL driver. Our next 5-year program goal is to produce a 100 kW-class FEL laser and multi-MW class electron beam in average, quasi-continuous wave operation. Conceptual and engineering design options needed for such a very high-power operation will be discussed to improve and to upgrade the existing facility.

  20. Contemporary frameless intracranial biopsy techniques: Might variation in safety and efficacy be expected?

    NARCIS (Netherlands)

    I.S.C. Verploegh (Iris S. C.); V. Volovici (Victor); I. Haitsma (Iain); J.W. Schouten (Joost); C.M.F. Dirven (Clemens); J.M. Kros (Johan); R. Dammers (Ruben)

    2015-01-01

    textabstractBackground: Frameless stereotactic neuronavigation has proven to be a feasible technology to acquire brain biopsies with good accuracy and little morbidity and mortality. New systems are constantly introduced into the neurosurgical armamentarium, although few studies have actually

  1. Contemporary frameless intracranial biopsy techniques: Might variation in safety and efficacy be expected?

    NARCIS (Netherlands)

    I.S.C. Verploegh (Iris S. C.); V. Volovici (Victor); I. Haitsma (Iain); J.W. Schouten (Joost); C.M.F. Dirven (Clemens); J.M. Kros (Johan); R. Dammers (Ruben)

    2015-01-01

    textabstractBackground: Frameless stereotactic neuronavigation has proven to be a feasible technology to acquire brain biopsies with good accuracy and little morbidity and mortality. New systems are constantly introduced into the neurosurgical armamentarium, although few studies have actually evalua

  2. Current status of frameless anchored IUD for immediate intracesarean insertion.

    Science.gov (United States)

    Wildemeersch, Dirk; Goldstuck, Norman D; Hasskamp, Thomas

    2016-01-01

    Immediate postpartum intrauterine device (IUD) insertion deserves great attention as it can provide immediate, timely and convenient contraception plus the added benefit of preventing repeat unintended pregnancies. Although women post vaginal delivery can benefit from immediate post-placenta contraception, women undergoing Cesarean section clearly need contraception, as an inter-delivery interval shorter than 18 months places them at a high risk for uterine rupture. The main drawback of currently available framed IUD devices for immediate postpartum insertion of an IUD is their high expulsion and displacement rates when inserted immediately postpartum after both vaginal and Cesarean delivery. Current research suggests that a brief window of opportunity exists of 10 minutes for insertion of conventional IUDs after which time expulsion rates both immediately and over time are greatly enhanced. This paper summarizes the current research conducted to overcome the expulsion problems associated with conventional T-shaped devices as well as through the use of an anchored frameless device. In the 1970s and 1980s, attempts were made to solve the expulsion problem by modifying existing devices, such as adding absorbable sutures (Delta-T) or additional appendages. These attempts proved to be clinically unsuccessful as the catgut suture added to the transverse arms did not provide sufficient resistance to prevent downward displacement and expulsion. An anchoring technique to suspend a copper IUD to the fundus of the uterus was developed in Belgium in the 1980s and has been the subject of extensive ongoing clinical research since 1985. Recently the frameless copper releasing anchor IUD, GyneFix, has been tested for postplacental insertion. Initially, the anchor was modified by the inclusion of a biodegradable cone which was added below the anchoring knot. Clinical studies confirmed the adequacy of this approach suggesting that it was technically possible to anchor an IUD

  3. Analytical bunch compression studies for a linac-based electron accelerator

    Directory of Open Access Journals (Sweden)

    M. Schreck

    2015-10-01

    Full Text Available The current paper deals with analytical bunch compression studies for FLUTE whose results are compared to simulations. FLUTE is a linac-based electron accelerator with a design energy of approximately 40 MeV currently being constructed at the Karlsruhe Institute of Technology. One of the goals of FLUTE is to generate electron bunches with their length lying in the femtosecond regime. In the first phase this will be accomplished using a magnetic bunch compressor. This compressor forms the subject of the studies presented. The paper is divided into two parts. The first part deals with pure geometric investigations of the bunch compressor where space charge effects and the backreaction of bunches with coherent synchrotron radiation are neglected. The second part is dedicated to the treatment of space charge effects. The upshot is that the analytical results in the two parts agree quite well with what is obtained from simulations. This paper shall form the basis for future analytical studies of the FLUTE bunch compressor and of bunch compression, in general.

  4. A Recirculating Linac-Based Facility for Ultrafast X-Ray Science

    Energy Technology Data Exchange (ETDEWEB)

    J. N. Corlett; W. A. Barletta; S. DeSantis; L. Doolittle; W. M. Fawley; M.A. Green; P. Heimann; S. Leone; S. Lidia; D. Li; A. Ratti; K. Robinson; R. Schoenlein; J. Staples; W. Wan; R. Wells; A.Wolski; A. Zholents; F. Parmigiani; M. Placidi; W. Pirkl; R. A. Rimmer; S. Wang

    2003-05-01

    We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac [1,2], in particular the incorporation of EUV and soft x-ray production. The project has been named LUX--Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10's fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short pulse photon production in the 1-10 keV range. High brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by f our passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

  5. A recirculating linac-based facility for ultrafast X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wolski, A.; Zholents, A.; Placidi, M.; Pirkl, W.; Parmigiani, F.

    2003-05-06

    We present an updated design for a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac, in particular the incorporation of EUV and soft x-ray production. The project has been named LUX - Linac-based Ultrafast X-ray facility. The source produces intense x-ray pulses with duration of 10-100 fs at a 10 kHz repetition rate, with synchronization of 10 s fs, optimized for the study of ultra-fast dynamics. The photon range covers the EUV to hard x-ray spectrum by use of seeded harmonic generation in undulators, and a specialized technique for ultra-short-pulse photon production in the 1-10 keV range. High-brightness rf photocathodes produce electron bunches which are optimized either for coherent emission in free-electron lasers, or to provide a large x/y emittance ration and small vertical emittance which allows for manipulation to produce short-pulse hard x-rays. An injector linac accelerates the beam to 120 MeV, and is followed by four passes through a 600-720 MeV recirculating linac. We outline the major technical components of the proposed facility.

  6. A tunable, linac based, intense, broad-band THz source forpump-probe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schmerge, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Adolphsen, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Corbett, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dolgashev, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Durr, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fazio, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fisher, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Frisch, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gaffney, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Guehr, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hettel, B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hoffmann, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hogan, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Huang, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Kirchmann, P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Limborg, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lindenberg, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loos, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Maxwell, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Nilsson, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Raubenheimer, T. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Reis, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Ross, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Shen, Z. -X. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stupakov, G. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tantawi, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Tian, K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Wu, Z. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Xiang, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Yakimenko, V. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-02

    We propose an intense THz source with tunable frequency and bandwidth that can directly interact with the degrees of freedom that determine the properties of materials and thus provides a new tool for controlling and directing these ultrafast processes as well as aiding synthesis of new materials with new functional properties. This THz source will broadly impact our understanding of dynamical processes in matter at the atomic-scale and in real time. Established optical pumping schemes using femtosecond visible frequency laser pulses for excitation are extended into the THz frequency regime thereby enabling resonant excitation of bonds in correlated solid state materials (phonon pumping), to drive low energy electronic excitations, to trigger surface chemistry reactions, and to all-optically bias a material with ultrashort electric fields or magnetic fields. A linac-based THz source can supply stand-alone experiments with peak intensities two orders of magnitude stronger than existing laser-based sources, but when coupled with atomic-scale sensitive femtosecond x-ray probes it opens a new frontier in ultrafast science with broad applications to correlated materials, interfacial and liquid phase chemistry, and materials in extreme conditions.

  7. Optical guiding and beam bending in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Scharlemann, E.T.

    1987-01-01

    The electron beam in a free-electron laser (FEL) can act as an optical fiber, guiding or bending the optical beam. The refractive and gain effects of the bunched electron beam can compensate for diffraction, making possible wigglers that are many Rayleigh ranges (i.e., characteristic diffraction lengths) long. The origin of optical guiding can be understood by examining gain and refractive guiding in a fiber with a complex index of refraction, providing a mathematical description applicable also to the FEL, with some extensions. In the exponential gain regime of the FEL, the electron equations of motion must be included, but a self-consistent description of exponential gain with diffraction fully included becomes possible. The origin of the effective index of refraction of an FEL is illustrated with a simple example of bunched, radiating dipoles. Some of the properties of the index of refraction are described. The limited experimental evidence for optical beam bending is summarized. The evidence does not yet provide conclusive proof of the existence of optical guiding, but supports the idea. Finally, the importance of refractive guiding for the performance of a high-gain tapered-wiggler FEL amplifier is illustrated with numerical simulations.

  8. Management of primary dysmenorrhea in young women with frameless LNG-IUS

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2014-06-01

    Full Text Available Dirk Wildemeersch,1 Sohela Jandi,2 Ansgar Pett,2 Thomas Hasskamp3 1Gynecological Outpatient Clinic and IUD Training Center, Ghent, Belgium; 2Gynecological Outpatient Clinic, Berlin, Germany; 3GynMünster, Münster, Germany Abstract: The objective of this paper is to discuss the potential advantages of intrauterine treatment with a frameless levonorgestrel (LNG-releasing intrauterine system (IUS in young women presenting with primary dysmenorrhea associated with heavy menstrual bleeding. The paper is based on clinical reports of 21 cases of primary and secondary dysmenorrhea treated with the frameless LNG-IUS. Three typical examples of young women between 16 and 20 years of age, who presented with moderate-to-severe primary dysmenorrhea associated with heavy menstrual bleeding, are presented as examples. Following pelvic examination, including vaginal sonography, a frameless LNG-IUS, releasing 20 µg of LNG/day, was inserted. The three patients developed amenorrhea, or scanty menstrual bleeding, and absence of pain complaints within a few months. We conclude that continuous, intrauterine progestogen delivery could be a treatment of choice of this inconvenient condition. In addition, the good experiences with the frameless LNG-IUS in other studies suggests that the frameless design may be preferred over a framed LNG-IUS, as the absence of a frame, resulting in optimal tolerance, is particularly advantageous in these women. Keywords: heavy menstrual bleeding, contraception, FibroPlant, intrauterine system

  9. Project for the development of the linac based NCT facility in University of Tsukuba.

    Science.gov (United States)

    Kumada, H; Matsumura, A; Sakurai, H; Sakae, T; Yoshioka, M; Kobayashi, H; Matsumoto, H; Kiyanagi, Y; Shibata, T; Nakashima, H

    2014-06-01

    A project team headed by University of Tsukuba launched the development of a new accelerator based BNCT facility. In the project, we have adopted Radio-Frequency Quadrupole (RFQ)+Drift Tube Linac (DTL) type linac as proton accelerators. Proton energy generated from the linac was set to 8MeV and average current was 10mA. The linac tube has been constructed by Mitsubishi Heavy Industry Co. For neutron generator device, beryllium is selected as neutron target material; high intensity neutrons are generated by the reaction with beryllium and the 80kW proton beam. Our team chose beryllium as the neutron target material. At present beryllium target system is being designed with Monte-Carlo estimations and heat analysis with ANSYS. The neutron generator consists of moderator, collimator and shielding. It is being designed together with the beryllium target system. We also acquired a building in Tokai village; the building has been renovated for use as BNCT treatment facility. It is noteworthy that the linac tube had been installed in the facility in September 2012. In BNCT procedure, several medical devices are required for BNCT treatment such as treatment planning system, patient positioning device and radiation monitors. Thus these are being developed together with the linac based neutron source. For treatment planning system, we are now developing a new multi-modal Monte-Carlo treatment planning system based on JCDS. The system allows us to perform dose estimation for BNCT as well as particle radiotherapy and X-ray therapy. And the patient positioning device can navigate a patient to irradiation position quickly and properly. Furthermore the device is able to monitor movement of the patient׳s position during irradiation.

  10. Resource pooling for frameless network architecture with adaptive resource allocation

    Institute of Scientific and Technical Information of China (English)

    XU XiaoDong; WANG Da; TAO XiaoFeng; SVENSSON Tommy

    2013-01-01

    The system capacity for future mobile communication needs to be increased to fulfill the emerging requirements of mobile services and innumerable applications. The cellular topology has for long been regarded as the most promising way to provide the required increase in capacity. However with the emerging densification of cell deployments, the traditional cellular structure limits the efficiency of the resource, and the coordination between different types of base stations is more complicated and entails heavy cost. Consequently, this study proposes frameless network architecture (FNA) to release the cell boundaries, enabling the topology needed to implement the FNA resource allocation strategy. This strategy is based on resource pooling incorporating a new resource dimension-antenna/antenna array. Within this architecture, an adaptive resource allocation method based on genetic algorithm is proposed to find the optimal solution for the multi-dimensional resource allocation problem. Maximum throughput and proportional fair resource allocation criteria are considered. The simulation results show that the proposed architecture and resource allocation method can achieve performance gains for both criteria with a relatively low complexity compared to existing schemes.

  11. Accuracy and precision of targeting using frameless stereotactic system in deep brain stimulator implantation surgery

    Directory of Open Access Journals (Sweden)

    Mayur Sharma

    2014-01-01

    Full Text Available Objectives: To assess the accuracy of targeting using NexFrame frameless targeting system during deep brain stimulation (DBS surgery. Materials and Methods: Fifty DBS leads were implanted in 33 patients using the NexFrame (Medtronic, Minneapolis, MN targeting system. Postoperative thin cut CT scans were used for lead localization. X, Y, Z coordinates of the tip of the lead were calculated and compared with the intended target coordinates to assess the targeting error. Comparative frame-based data set was obtained from randomly selected 33 patients during the same period that underwent 65 lead placements using Leksell stereotactic frame. Euclidean vector was calculated for directional error. Multivariate analysis of variance was used to compare the accuracy between two systems. Results: The mean error of targeting using frameless system in medio-lateral plane was 1.4 mm (SD ± 1.3, in antero-posterior plane was 0.9 mm (SD ± 1.0 and in supero-inferior plane Z was 1.0 mm (SD ± 0.9. The mean error of targeting using frame-based system in medio-lateral plane was 1.0 mm (SD ± 0.7, in antero-posterior plane was 0.9 mm (SD ± 0.5 and in supero-inferior plane Z was 0.7 mm (SD ± 0.6. The error in targeting was significantly more (P = 0.03 in the medio-lateral plane using the frameless system as compared to the frame-based system. Mean targeting error in the Euclidean directional vector using frameless system was 2.2 (SD ± 1.6 and using frame-based system was 1.7 (SD ± 0.6 (P = 0.07. There was significantly more error in the first 25 leads placed using the frameless system than the second 25 leads (P = 0.0015. Conclusion: The targeting accuracy of the frameless system was lower as compared to frame-based system in the medio-lateral direction. Standard deviations (SDs were higher using frameless system as compared to the frame-based system indicating lower accuracy of this system. Error in targeting should be considered while using frameless

  12. Compact Short-Pulsed Electron Linac Based Neutron Sources for Precise Nuclear Material Analysis

    Science.gov (United States)

    Uesaka, M.; Tagi, K.; Matsuyama, D.; Fujiwara, T.; Dobashi, K.; Yamamoto, M.; Harada, H.

    2015-10-01

    An X-band (11.424GHz) electron linac as a neutron source for nuclear data study for the melted fuel debris analysis and nuclear security in Fukushima is under development. Originally we developed the linac for Compton scattering X-ray source. Quantitative material analysis and forensics for nuclear security will start several years later after the safe settlement of the accident is established. For the purpose, we should now accumulate more precise nuclear data of U, Pu, etc., especially in epithermal (0.1-10 eV) neutrons. Therefore, we have decided to modify and install the linac in the core space of the experimental nuclear reactor "Yayoi" which is now under the decommission procedure. Due to the compactness of the X-band linac, an electron gun, accelerating tube and other components can be installed in a small space in the core. First we plan to perform the time-of-flight (TOF) transmission measurement for study of total cross sections of the nuclei for 0.1-10 eV energy neutrons. Therefore, if we adopt a TOF line of less than 10m, the o-pulse length of generated neutrons should be shorter than 100 ns. Electronenergy, o-pulse length, power, and neutron yield are ~30 MeV, 100 ns - 1 micros, ~0.4 kW, and ~1011 n/s (~103 n/cm2/s at samples), respectively. Optimization of the design of a neutron target (Ta, W, 238U), TOF line and neutron detector (Ce:LiCAF) of high sensitivity and fast response is underway. We are upgrading the electron gun and a buncher to realize higher current and beam power with a reasonable beam size in order to avoid damage of the neutron target. Although the neutron flux is limited in case of the X-band electron linac based source, we take advantage of its short pulse aspect and availability for nuclear data measurement with a short TOF system. First, we form a tentative configuration in the current experimental room for Compton scattering in 2014. Then, after the decommissioning has been finished, we move it to the "Yayoi" room and perform

  13. TH-A-9A-05: Initial Setup Accuracy Comparison Between Frame-Based and Frameless Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, T; Sheu, R; Todorov, B; Green, S; Blacksburg, S; Lo, Y [Mount Sinai Medical Center, New York, NY (United States)

    2014-06-15

    Purpose: To evaluate initial setup accuracy for stereotactic radiosurgery (SRS) between Brainlab frame-based and frameless immobilization system, also to discern the magnitude frameless system has on setup parameters. Methods: The correction shifts from the original setup were compared for total 157 SRS cranial treatments (69 frame-based vs. 88 frameless). All treatments were performed on a Novalis linac with ExacTrac positioning system. Localization box with isocenter overlay was used for initial setup and correction shift was determined by ExacTrac 6D auto-fusion to achieve submillimeter accuracy for treatment. For frameless treatments, mean time interval between simulation and treatment was 5.7 days (range 0–13). Pearson Chi-Square was used for univariate analysis. Results: The correctional radial shifts (mean±STD, median) for the frame and frameless system measured by ExacTrac were 1.2±1.2mm, 1.1mm and 3.1±3.3mm, 2.0mm, respectively. Treatments with frameless system had a radial shift >2mm more often than those with frames (51.1% vs. 2.9%; p<.0001). To achieve submillimeter accuracy, 85.5% frame-based treatments did not require shift and only 23.9% frameless treatment could succeed with initial setup. There was no statistical significant system offset observed in any direction for either system. For frameless treatments, those treated ≥ 3 days from simulation had statistically higher rates of radial shifts between 1–2mm and >2mm compared to patients treated in a shorter amount of time from simulation (34.3% and 56.7% vs. 28.6% and 33.3%, respectively; p=0.006). Conclusion: Although image-guided positioning system can also achieve submillimeter accuracy for frameless system, users should be cautious regarding the inherent uncertainty of its capability of immobilization. A proper quality assurance procedure for frameless mask manufacturing and a protocol for intra-fraction imaging verification will be crucial for frameless system. Time interval between

  14. Application of frameless stereotactic aspiration in the treatment of hypertension cerebral hemorrhage

    Directory of Open Access Journals (Sweden)

    You-san ZHANG

    2016-09-01

    Full Text Available Objective  To investigate the technical points and clinical outcomes of frameless stereotactic aspiration in treatment of patients with hypertension cerebral hemorrhage (HPCH. Methods  The clinical data of 68 consecutive patients with HPCH, treated with frameless stereotactic aspiration from Jan. 2012 to Jun. 2014, were retrospectively analyzed, and compared to that of 45 patients treated in the meantime by frame-based stereotactic aspiration. The surgical results, procedure-related complications and clinical prognosis were evaluated. Results  For the patients treated with frameless stereotactic aspiration, the median age was 53.3 years (range 36-80, the mean initial Glasgow coma scale score was over 5. Among them seven patients died within a month after operation: 3 died of respiratory failure, 2 of cerebral edema and 2 of rehemorrhage. At the six-months follow-up, the good recovery rate (gradeⅠ-Ⅲof ADL was 77.9%(53/68, better than that of patients treated with frame-based stereotactic aspiration (60.0%, P<0.05. Conclusion  Frameless stereotactic aspiration for HPCH is easy to operate, minimal invasion and safe procedure with low mortality and rehemorrhage rate. DOI: 10.11855/j.issn.0577-7402.2016.08.12

  15. Intrauterine levonorgestrel delivery with frameless fibrous delivery system: review of clinical experience.

    Science.gov (United States)

    Wildemeersch, Dirk; Andrade, Amaury; Goldstuck, Norman D; Hasskamp, Thomas; Jackers, Geert

    2017-01-01

    The concept of using a frameless intrauterine device (IUD) instead of the conventional plastic framed IUD is not new. Frameless copper IUDs have been available since the late 1990s. They rely on an anchoring system to retain in the uterine cavity. The clinical experience with these IUDs suggests that frameless IUDs fit better as they are thin and, therefore, do not disturb or irritate the uterus. High tolerance and continuation rates have been achieved as complaints of pain are virtually nonexistent and the impact on menstrual blood loss is minimal. Conventional levonorgestrel-releasing intrauterine systems (LNG-IUSs) are very popular as they significantly reduce menstrual bleeding and provide highly effective contraception. However, continuation of use remains problematic, particularly in young users. Total or partial expulsion and displacement of the LNG-IUS also occur too often due to spatial incompatibility within a small uterine cavity, as strong uterine contractions originate, attempting to get rid of the bothersome IUD/IUS. If not expelled, embedment ensues, often leading to chronic pain and early removal of the IUD/IUS. Several studies conducted recently have requested attention to the relationship between the LNG-IUS and the endometrial cavity. Some authors have proposed to measure the cavity width prior to inserting an IUD, as many uterine cavities are much smaller than the currently existing LNG-IUSs. A frameless fibrous drug delivery system fits, in principle, in all uterine cavities and may therefore be preferable to framed drug delivery systems. This review examines the clinical performance, acceptability, and potential of the frameless LNG-IUS (FibroPlant(®)) when used for contraception, treatment of heavy menstrual bleeding, dysmenorrhea, and endometrial suppression in women using estrogen replacement therapy, endometrial hyperplasia, and other gynecological conditions. The review concludes that FibroPlant LNG-IUS offers unique advantages in

  16. Intrauterine levonorgestrel delivery with frameless fibrous delivery system: review of clinical experience

    Science.gov (United States)

    Wildemeersch, Dirk; Andrade, Amaury; Goldstuck, Norman D; Hasskamp, Thomas; Jackers, Geert

    2017-01-01

    The concept of using a frameless intrauterine device (IUD) instead of the conventional plastic framed IUD is not new. Frameless copper IUDs have been available since the late 1990s. They rely on an anchoring system to retain in the uterine cavity. The clinical experience with these IUDs suggests that frameless IUDs fit better as they are thin and, therefore, do not disturb or irritate the uterus. High tolerance and continuation rates have been achieved as complaints of pain are virtually nonexistent and the impact on menstrual blood loss is minimal. Conventional levonorgestrel-releasing intrauterine systems (LNG-IUSs) are very popular as they significantly reduce menstrual bleeding and provide highly effective contraception. However, continuation of use remains problematic, particularly in young users. Total or partial expulsion and displacement of the LNG-IUS also occur too often due to spatial incompatibility within a small uterine cavity, as strong uterine contractions originate, attempting to get rid of the bothersome IUD/IUS. If not expelled, embedment ensues, often leading to chronic pain and early removal of the IUD/IUS. Several studies conducted recently have requested attention to the relationship between the LNG-IUS and the endometrial cavity. Some authors have proposed to measure the cavity width prior to inserting an IUD, as many uterine cavities are much smaller than the currently existing LNG-IUSs. A frameless fibrous drug delivery system fits, in principle, in all uterine cavities and may therefore be preferable to framed drug delivery systems. This review examines the clinical performance, acceptability, and potential of the frameless LNG-IUS (FibroPlant®) when used for contraception, treatment of heavy menstrual bleeding, dysmenorrhea, and endometrial suppression in women using estrogen replacement therapy, endometrial hyperplasia, and other gynecological conditions. The review concludes that FibroPlant LNG-IUS offers unique advantages in reducing

  17. Image quality and dose distributions of three linac-based imaging modalities

    Energy Technology Data Exchange (ETDEWEB)

    Dzierma, Yvonne; Ames, Evemarie; Nuesken, Frank; Palm, Jan; Licht, Norbert; Ruebe, Christian [Universitaetsklinikum des Saarlandes, Klinik fuer Strahlentherapie und Radioonkologie, Homburg/Saar (Germany)

    2015-04-01

    Linac-based patient imaging is possible with a variety of techniques using different photon energies. The purpose of this work is to compare three imaging systems operating at 6 MV, flattening free filter (FFF) 1 MV, and 121 kV. The dose distributions of all pretreatment set-up images (over 1,000) were retrospectively calculated on the planning computed tomography (CT) images for all patients with prostate and head-and-neck cancer treated at our institution in 2013. We analyzed the dose distribution and the dose to organs at risk. For head-and-neck cancer patients, the imaging dose from 6-MV cone beam CT (CBCT) reached maximum values at around 8 cGy. The 1-MV CBCT dose was about 63-79 % of the 6-MV CBCT dose for all organs at risk. Planar imaging reduced the imaging dose from CBCT to 30-40 % for both megavoltage modalities. The dose from the kilovoltage CBCT was 4-10 % of the 6-MV CBCT dose. For prostate cancer patients, the maximum dose from 6-MV CBCT reached 13-15 cGy, and was reduced to 66-73 % for 1 MV. Planar imaging reduces the MV CBCT dose to 10-20 %. The kV CBCT dose is 15-20 % of the 6-MV CBCT dose, slightly higher than the dose from MV axes. The dose distributions differ markedly in response to the different beam profiles and dose-depth characteristics. (orig.) [German] Linac-basierte Bildgebung zur Patientenlagerung ist mit einer Vielzahl von Techniken unterschiedlicher Photonenenergien moeglich. Ziel dieser Arbeit ist der Vergleich dreier Bildgebungssysteme mit 6 MV (Megavolt), FFF 1 MV, und 121 kV (Kilovolt). Fuer alle im Jahr 2013 an unserer Klinik behandelten Prostata- und HNO-Patienten wurden retrospektiv die Dosisverteilungen aller Verifikationsaufnahmen (ueber 1000 insgesamt) auf der Planungs-Computertomographie (CT) berechnet. Wir analysierten die Dosisverteilung und die Dosis an den Risikoorganen. Bei HNO-Patienten erreichte die Dosis von 6 MV ''Cone-beam''-CT (CBCT)Maximalwerte um 8 cGy. Mit 1 MV wird die Dosis auf 63

  18. Retrospective analysis of linac-based radiosurgery for arteriovenous malformations and testing of the Flickinger formula in predicting radiation injury

    Energy Technology Data Exchange (ETDEWEB)

    Cetin, I.A. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology; Marmara Univ., Ustkaynarca/Pendik (Turkey). Dept. of Radiation Oncology; Ates, R.; Dhaens, J.; Storme, G. [Universitair Ziekenhuis Brussel (Belgium). Dept. of Radiation Oncology

    2012-12-15

    Background and purpose: The aim of the study was to validate the use of linac-based radiosurgery in arteriovenous malformation (AVM) patients and to predict complications using an integrated logistic formula (ILF) in comparison with clinical outcomes. Patients and methods: The results of radiosurgery in 92 AVM patients were examined. All patients were treated with linac-based radiosurgery. Of these, 70 patients were followed for 12-45 months (median, 24 months) and were analyzed. The treated volume varied from 0.09 to 26.95 cm{sup 3} (median, 2.3 cm{sup 3}) and the median marginal dose was 20 Gy (range, 10.4-22). The median 12-Gy volume was 9.94 cm{sup 3} (range, 0.74-60.09 cm{sup 3}). Patients and lesion characteristics potentially affecting nidus obliteration and excellent outcome were evaluated by performing a log-rank test and univariate and multivariate analyses. The risk for radiation injury (RRI) was calculated with an integrated logistic formula. The predictive power of the RRI was assessed by calculating the area under the receiver operating characteristic (ROC) curve. Results: Follow-up magnetic resonance (MR) angiography revealed complete AVM obliteration in 56 of 70 patients. The MR angiography confirmed an obliteration rate of 80%. The annual hemorrhage rate was 1.4% for the first 2 years after radiosurgery and 0% thereafter. The number of patients with an excellent outcome was 48 (68%). Factors associated with better obliteration were higher radiation dose to the lesion margins [12-Gy volume (V12) > 10 cm{sup 3}], small volume, and a Pollock-Flickinger score less than 1.49; those predicting excellent outcomes were V12 < 10 cm{sup 3}, small volume, and Pollock-Flickinger score less than 1.49, as determined by multivariate analyses. Factors associated with radiation injury were V12 > 10 cm{sup 3} (p=0.03) and volume greater than 2 cm{sup 3} (p=0.001), as determined by a univariate analysis. The analyses showed an ROC of 0.66. Conclusion: These data

  19. Intrauterine levonorgestrel delivery with frameless fibrous delivery system: review of clinical experience

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2017-01-01

    Full Text Available Dirk Wildemeersch,1 Amaury Andrade,2 Norman D Goldstuck,3 Thomas Hasskamp,4 Geert Jackers5 1Gynecological Outpatient Clinic and IUD Training Center, Ghent, Belgium; 2Centro de Biologia da Reprodução, Universidade Federal Juiz de Fora, Juiz de Fora, Brazil; 3Department of Obstetrics and Gynaecology, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Hospital, Western Cape, South Africa; 4Klinik für Operativen Gynäkologie, GynMünster, Münster, Germany; 5Applied Controlled Release, Technology Park, Ghent (Zwijnaarde, Belgium Abstract: The concept of using a frameless intrauterine device (IUD instead of the conventional plastic framed IUD is not new. Frameless copper IUDs have been available since the late 1990s. They rely on an anchoring system to retain in the uterine cavity. The clinical experience with these IUDs suggests that frameless IUDs fit better as they are thin and, therefore, do not disturb or irritate the uterus. High tolerance and continuation rates have been achieved as complaints of pain are virtually nonexistent and the impact on menstrual blood loss is minimal. Conventional levonorgestrel-releasing intrauterine systems (LNG-IUSs are very popular as they significantly reduce menstrual bleeding and provide highly effective contraception. However, continuation of use remains problematic, particularly in young users. Total or partial expulsion and displacement of the LNG-IUS also occur too often due to spatial incompatibility within a small uterine cavity, as strong uterine contractions originate, attempting to get rid of the bothersome IUD/IUS. If not expelled, embedment ensues, often leading to chronic pain and early removal of the IUD/IUS. Several studies conducted recently have requested attention to the relationship between the LNG-IUS and the endometrial cavity. Some authors have proposed to measure the cavity width prior to inserting an IUD, as many uterine cavities are much smaller than the

  20. Investigating a multi-purpose target for electron linac based photoneutron sources for BNCT of deep-seated tumors

    Energy Technology Data Exchange (ETDEWEB)

    Masoudi, S. Farhad, E-mail: masoudi@kntu.ac.ir; Rasouli, Fatemeh S.

    2015-08-01

    Recent studies in BNCT have focused on investigating appropriate neutron sources as alternatives for nuclear reactors. As the most prominent facilities, the electron linac based photoneutron sources benefit from two consecutive reactions, (e, γ) and (γ, n). The photoneutron sources designed so far are composed of bipartite targets which involve practical problems and are far from the objective of achieving an optimized neutron source. This simulation study deals with designing a compact, optimized, and geometrically simple target for a photoneutron source based on an electron linac. Based on a set of MCNPX simulations, tungsten is found to have the potential of utilizing as both photon converter and photoneutron target. Besides, it is shown that an optimized dimension for such a target slows-down the produced neutrons toward the desired energy range while keeping them economy, which makes achieving the recommended criteria for BNCT of deep-tumors more available. This multi-purpose target does not involve complicated designing, and can be considered as a significant step toward finding application of photoneutron sources for in-hospital treatments. In order to shape the neutron beam emitted from such a target, the beam is planned to pass through an optimized arrangement of materials composed of moderators, filters, reflector, and collimator. By assessment with the recommended in-air parameters, it is shown that the designed beam provides high intensity of desired neutrons, as well as low background contamination. The last section of this study is devoted to investigate the performance of the resultant beam in deep tissue. A typical simulated liver tumor, located within a phantom of human body, was subjected to the irradiation of the designed spectrum. The dosimetric results, including evaluated depth-dose curves and carried out in-phantom parameters show that the proposed configuration establishes acceptable agreement between the appropriate neutron intensity, and

  1. Tiled large-screen three-dimensional display consisting of frameless multi-view display modules.

    Science.gov (United States)

    Takaki, Yasuhiro; Tokoro, Masayuki; Hirabayashi, Kenji

    2014-03-24

    To realize large-screen three-dimensional (3D) displays, frameless multi-view display modules are arranged two-dimensionally. This paper proposes a multi-view display module in which a multi-view flat-panel display is projected onto a screen of the module to provide a frameless screen. The display module consists of a multi-view flat-panel display, an imaging lens, an aperture, a screen lens, and a vertical diffuser. Prototype display modules were constructed having a screen size of 27.3 in., a 3D resolution of 320 × 200, and 144 viewpoints. Four modules were tiled vertically to provide a screen size of 62.4 in. Distortions in the screen imaging and viewpoint generation were corrected.

  2. The Experimental Research on the Frameless Registration of DSA/CT Images

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong-feng; LI Wen; ZENG Pei-feng; ZHAO Jun

    2006-01-01

    DSA images show vessels with clarity and CT images show bones distinctly. In this paper, we present an experimental research on the frameless registration of DSA/CT images based on localization algorithm. With four external markers, the vessels and bones in human brain can be integrated. The mean accuracy of simulated experiment is about 2.0 mm. The experiment proved that the 3D images composed cerebral anatomy and vasculature could help neurosurgeons perform accurate diagnosis and make right operation planning.

  3. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Taynna Vernalha Rocha [Faculdades Pequeno Principe (FPP), Curitiba, PR (Brazil); Cordova Junior, Arno Lotar; Almeida, Cristiane Maria; Piedade, Pedro Argolo; Silva, Cintia Mara da, E-mail: taynnavra@gmail.com [Centro de Radioterapia Sao Sebastiao, Florianopolis, SC (Brazil); Brincas, Gabriela R. Baseggio [Centro de Diagnostico Medico Imagem, Florianopolis, SC (Brazil); Marins, Priscila; Soboll, Danyel Scheidegger [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2016-03-15

    Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5- mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. (author)

  4. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom*

    Science.gov (United States)

    Almeida, Taynná Vernalha Rocha; Cordova Junior, Arno Lotar; Piedade, Pedro Argolo; da Silva, Cintia Mara; Marins, Priscila; Almeida, Cristiane Maria; Brincas, Gabriela R. Baseggio; Soboll, Danyel Scheidegger

    2016-01-01

    Objective To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART)-210 anthropomorphic head phantom, into which we inserted four 5mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used. PMID:27141132

  5. Analysis of translational errors in frame-based and frameless cranial radiosurgery using an anthropomorphic phantom

    Directory of Open Access Journals (Sweden)

    Taynná Vernalha Rocha Almeida

    2016-04-01

    Full Text Available Abstract Objective: To evaluate three-dimensional translational setup errors and residual errors in image-guided radiosurgery, comparing frameless and frame-based techniques, using an anthropomorphic phantom. Materials and Methods: We initially used specific phantoms for the calibration and quality control of the image-guided system. For the hidden target test, we used an Alderson Radiation Therapy (ART-210 anthropomorphic head phantom, into which we inserted four 5mm metal balls to simulate target treatment volumes. Computed tomography images were the taken with the head phantom properly positioned for frameless and frame-based radiosurgery. Results: For the frameless technique, the mean error magnitude was 0.22 ± 0.04 mm for setup errors and 0.14 ± 0.02 mm for residual errors, the combined uncertainty being 0.28 mm and 0.16 mm, respectively. For the frame-based technique, the mean error magnitude was 0.73 ± 0.14 mm for setup errors and 0.31 ± 0.04 mm for residual errors, the combined uncertainty being 1.15 mm and 0.63 mm, respectively. Conclusion: The mean values, standard deviations, and combined uncertainties showed no evidence of a significant differences between the two techniques when the head phantom ART-210 was used.

  6. Setup Accuracy of the Novalis ExacTrac 6DOF System for Frameless Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Gevaert, Thierry, E-mail: thierry.gevaert@uzbrussel.be [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium); Verellen, Dirk; Tournel, Koen; Linthout, Nadine; Bral, Samuel; Engels, Benedikt; Collen, Christine; Depuydt, Tom; Duchateau, Michael; Reynders, Truus; Storme, Guy; De Ridder, Mark [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium)

    2012-04-01

    Purpose: Stereotactic radiosurgery using frame-based positioning is a well-established technique for the treatment of benign and malignant lesions. By contrast, a new trend toward frameless systems using image-guided positioning techniques is gaining mainstream acceptance. This study was designed to measure the detection and positioning accuracy of the ExacTrac/Novalis Body (ET/NB) for rotations and to compare the accuracy of the frameless with the frame-based radiosurgery technique. Methods and Materials: A program was developed in house to rotate reference computed tomography images. The angles measured by the system were compared with the known rotations. The accuracy of ET/NB was evaluated with a head phantom with seven lead beads inserted, mounted on a treatment couch equipped with a robotic tilt module, and was measured with a digital water level and portal films. Multiple hidden target tests (HTT) were performed to measure the overall accuracy of the different positioning techniques for radiosurgery (i.e., frameless and frame-based with relocatable mask or invasive ring, respectively). Results: The ET/NB system can detect rotational setup errors with an average accuracy of 0.09 Degree-Sign (standard deviation [SD] 0.06 Degree-Sign ), 0.02 Degree-Sign (SD 0.07 Degree-Sign ), and 0.06 Degree-Sign (SD 0.14 Degree-Sign ) for longitudinal, lateral, and vertical rotations, respectively. The average positioning accuracy was 0.06 Degree-Sign (SD 0.04 Degree-Sign ), 0.08 Degree-Sign (SD 0.06 Degree-Sign ), and 0.08 Degree-Sign (SD 0.07 Degree-Sign ) for longitudinal, lateral and vertical rotations, respectively. The results of the HTT showed an overall three-dimensional accuracy of 0.76 mm (SD 0.46 mm) for the frameless technique, 0.87 mm (SD 0.44 mm) for the relocatable mask, and 1.19 mm (SD 0.45 mm) for the frame-based technique. Conclusions: The study showed high detection accuracy and a subdegree positioning accuracy. On the basis of phantom studies, the

  7. Single-shot method for measuring femtosecond bunch length in linac-based free-electron lasers

    Directory of Open Access Journals (Sweden)

    Z. Huang

    2010-09-01

    Full Text Available There is growing interest in the generation and characterization of femtosecond and subfemtosecond pulses from linac-based free-electron lasers (FELs. In this report, following the method of Ricci and Smith [Phys. Rev. ST Accel. Beams 3, 032801 (2000PRABFM1098-440210.1103/PhysRevSTAB.3.032801], we investigate the measurement of the longitudinal bunch profile of an ultrashort electron bunch produced by these FELs. We show that this method can be applied in a straightforward manner at x-ray FEL facilities such as the Linac Coherent Light Source by slightly adjusting the second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final linac. We find that the linac wakefield strongly perturbs the measurement, and through analysis show that it can be compensated in a simple way. We demonstrate the effectiveness of this method and wakefield compensation through numerical simulations, including effects of coherent synchrotron radiation and longitudinal space charge. When used in conjunction with a high-resolution electron spectrometer, this method potentially reveals the temporal profile of the electron beam down to the femtosecond and subfemotsecond scale.

  8. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    CERN Document Server

    Li, Zhihui

    2014-01-01

    The continue wave (CW) high current proton linac has wide applications as the front end of the high power proton machines. The low energy part is the most difficult one and there is no widely accepted solution yet. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by the quadrupole doublets located between cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. The multi-particle beam dynamics simulations are performed with the help of the...

  9. Design of a 10 MeV normal conducting CW proton linac based on equidistant multi-gap CH cavities

    Science.gov (United States)

    Li, Zhi-Hui

    2015-09-01

    Continuous wave (CW) high current proton linacs have wide applications as the front end of high power proton machines. The low energy part of such a linac is the most difficult and there is currently no widely accepted solution. Based on the analysis of the focusing properties of the CW low energy proton linac, a 10 MeV low energy normal conducting proton linac based on equidistant seven-gap Cross-bar H-type (CH) cavities is proposed. The linac is composed of ten 7-gap CH cavities and the transverse focusing is maintained by quadrupole doublets located between the cavities. The total length of the linac is less than 6 meters and the average acceleration gradient is about 1.2 MeV/m. The electromagnetic properties of the cavities are investigated by Microwave Studio. At the nominal acceleration gradient the maximum surface electric field in the cavities is less than 1.3 times the Kilpatrick limit, and the Ohmic loss of each cavity is less than 35 kW. Multi-particle beam dynamics simulations are performed with Tracewin code, and the results show that the beam dynamics of the linac are quite stable, the linac has the capability to accelerate up to 30 mA beam with acceptable dynamics behavior. Supported by National Natural Science Foundation of China (11375122, 91126003)

  10. Deflecting RF cavity design for a recirculating linac based facility for ultrafast X-ray science (LUX)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Derun; Corlett, J.N.

    2003-05-01

    We report on superconducting deflecting RF cavity designs for a Recirculating Linac Based Facility for Ultrafast X-ray Science (LUX) at Lawrence Berkeley National Laboratory. The deflecting cavities operate in the lowest dipole mode and are required to produce a temporal correlation within flat electron bunches, as needed for x-ray compression in crystal optics. Deflecting voltage of up to 8.5-MV is required at 3.9-GHz. We present a 7-cell cavity design in this paper. Seven such cavities are required to generate the 8.5 MV deflecting voltage. Longitudinal and transverse impedance from LOM (lower order mode) and HOM (higher order mode) are simulated using the MAFIA code. Short-range and long-range wakefield excited through these impedances are calculated. Beam loading effects of the deflecting mode and LOM modes are estimated. Q values of the LOM monopole modes in the cavity may need to be damped to be below 10{sup 4}-10{sup 5} levels in order to maintain the required energy spread.

  11. Diffuse intrinsic pontine gliomas in children: Interest of robotic frameless assisted biopsy. A technical note.

    Science.gov (United States)

    Coca, H A; Cebula, H; Benmekhbi, M; Chenard, M P; Entz-Werle, N; Proust, F

    2016-12-01

    Diffuse intrinsic pontine gliomas (DIPG) constitute 10-15% of all brain tumors in the pediatric population; currently prognosis remains poor, with an overall survival of 7-14 months. Recently the indication of DIPG biopsy has been enlarged due to the development of molecular biology and various ongoing clinical and therapeutic trials. Classically a biopsy is performed using a stereotactic frame assisted procedure but the workflow may sometimes be heavy and more complex especially in children. In this study the authors present their experience with frameless robotic-guided biopsy of DIPG in a pediatric population. Retrospective study on a series of five consecutive pediatric patients harboring DIPG treated over a 4-year period. All patients underwent frameless robotic-guided biopsy via a transcerebellar approach. Among the 5 patients studied 3 were male and 2 female with a median age of 8.6 years [range 5 to 13 years]. Clinical presentation included ataxia, hemiparesis and cranial nerve palsy in all patients. MRI imaging of the lesion showed typical DIPG features (3 of them located in the pons) with hypo-intensity on T1 and hyper-intensity signal on T2 sequences and diffuse gadolinium enhancement. The mean procedure time was 56minutes (range 45 to 67minutes). No new postoperative neurological deficits were recorded. Histological diagnosis was achieved in all cases as follows: two anaplastic astrocytomas (grade III), two glioblastomas, and one diffuse astrocytoma (grade III). Frameless robotic assisted biopsy of DIPG in pediatric population is an easier, effective, safe and highly accurate method to achieve diagnosis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  12. Frameless stereotactic targeting devices: technical features, targeting errors and clinical results.

    Science.gov (United States)

    Widmann, Gerlig; Schullian, Peter; Ortler, Martin; Bale, Reto

    2012-03-01

    Brain biopsies (BB) and depth electrode placements (DEP) are increasingly performed using frameless stereotactic targeting devices. This paper is intended to provide a comprehensive review of the technical features, targeting errors and clinical results. A PubMed literature search from 1995-2010 was performed. (A) Modified stereotactic arcs, (B) arm-based devices with and without aiming facilities, and (C) skull affixed devices were found. Guidance technologies were navigation systems (all groups), prospective stereotaxy and custom designed platforms (group C). Mean total errors ranged between 4.4 and 5.4 mm for BB and 2.0 and 3.2 mm for DEP. Diagnostic yield of BB was 89-100%. The clinical success rate for DEP was 96-100%. Frameless stereotactic targeting devices may reach targeting errors and clinical results comparable with standard frame-based stereotaxy. Advantages and disadvantages of different devices should be acknowledged to ensure optimal technical performance. Copyright © 2011 John Wiley & Sons, Ltd.

  13. Use of frameless intrauterine devices and systems in young nulliparous and adolescent women: results of a multicenter study

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2014-08-01

    Full Text Available Dirk Wildemeersch,1 Sohela Jandi,2 Ansgar Pett,2 Kilian Nolte,3 Thomas Hasskamp,4 Marc Vrijens5 1Gynecological Outpatient Clinic and IUD Training Center, Ghent, Belgium; 2Gynecological Outpatient Clinic, Berlin, 3Gynecological Outpatient Clinic, Uetze, 4GynMünster, Münster, Germany; 5Gynecological Outpatient Clinic, Ghent, Belgium Background: The purpose of this study was to provide additional data on the experience with frameless copper and levonorgestrel (LNG intrauterine devices (IUDs in nulliparous and adolescent women. Methods: Nulliparous and adolescent women, 25 years of age or younger, using the frameless copper IUD or the frameless LNG-releasing intrauterine system (IUS, were selected from previous studies and a current multicenter post-marketing study with the frameless copper IUD. The small copper-releasing GyneFix® 200 IUD consists of four copper cylinders, each 5 mm long and only 2.2 mm wide. The frameless FibroPlant® LNG-IUS consists of a fibrous delivery system releasing the hormone levonorgestrel (LNG-IUS. The main features of these intrauterine contraceptives are that they are frameless, flexible, and anchored to the fundus of the uterus. Results: One hundred and fifty-four nulliparous and adolescent women participated in the combined study. One pregnancy occurred with the GyneFix 200 IUD after unnoticed early expulsion of the device (cumulative pregnancy rate 1.1 at one year. Two further expulsions were reported, one with the GyneFix 200 IUD and the other with the FibroPlant LNG-IUS. The cumulative expulsion rate at one year was 1.1 with the copper IUD and 2.2 with the LNG-IUS. The total discontinuation rate at one year was low (3.3 and 4.3 with the copper IUD and LNG-IUS, respectively and resulted in a high rate of continuation of use at one year (96.7 with the copper IUD and 95.7 with the LNG-IUS, respectively. Continuation rates for both frameless copper IUD and frameless LNG-IUS remained high at 3 years (>90%. There

  14. Potential role for LINAC-based stereotactic radiosurgery for the treatment of 5 or more radioresistant melanoma brain metastases.

    Science.gov (United States)

    Frakes, Jessica M; Figura, Nicholas B; Ahmed, Kamran A; Juan, Tzu-Hua; Patel, Neha; Latifi, Kujtim; Sarangkasiri, Siriporn; Strom, Tobin J; Chinnaiyan, Prakash; Rao, Nikhil G; Etame, Arnold B

    2015-11-01

    Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) is a treatment option for patients with melanoma in whom brain metastases have developed. Very limited data are available on treating patients with ≥5 lesions. The authors sought to determine the effectiveness of SRS in patients with ≥5 melanoma brain metastases. A retrospective analysis of metastatic melanoma treated with SRS in a single treatment session for ≥5 lesions was performed. Magnetic resonance imaging studies were reviewed post-SRS to evaluate local control (LC). Disease progression on imaging was defined using the 2009 Response Evaluation Criteria in Solid Tumors (RECIST). Survival curves were calculated from the date of brain metastases diagnosis or the date of SRS by using the Kaplan-Meier (KM) method. Univariate and multivariate analysis (UVA and MVA, respectively) were performed using the Cox proportional-hazards model. The authors identified 149 metastatic brain lesions treated in 28 patients. The median patient age was 60.5 years (range 38-83 years), and the majority of patients (24 [85.7%]) had extracranial metastases. Four patients (14.3%) had received previous whole-brain radiotherapy (WBRT), and 11 (39.3%) had undergone previous SRS. The median planning target volume (PTV) was 0.34 cm3 (range 0.01-12.5 cm3). Median follow-up was 6.3 months (range 1-46 months). At the time of treatment, 7% of patients were categorized as recursive partitioning analysis (RPA) Class I, 89% as RPA Class II, and 4% as RPA Class III. The rate of local failure was 11.4%. Kaplan-Meier LC estimates at 6 and 12 months were 91.3% and 82.2%, respectively. A PTV volume≥0.34 cm3 was a significant predictor of local failure on UVA (HR 16.1, 95% CI 3.2-292.6, ptreatment. The RPA class was a significant predictor of KM OS estimates from the date of treatment (p=0.02). Patients who did not receive WBRT after SRS treatment had decreased OS on MVA (HR 3.5, 95% CI 1.1-12.0, p=0.03), and patients who did not

  15. SU-E-T-438: Frameless Cranial Stereotactic Radiosurgery Immobilization Effectiveness Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, T; Green, S; Sheu, R; Lo, Y [Mount Sinai Medical Center, New York, NY (United States)

    2015-06-15

    Purpose: To evaluate immobilization effectiveness of Brainlab frameless mask in cranial stereotactic radiosurgery (SRS). Methods: Two sets of setup images were collected pre-and post-treatment for 24 frameless SRS cases. The pre-treatment images were obtained after applying 2D-2D kV image-guided shifts with patients in treatment position and approved by physicians; the post-treatment images were taken immediately after treatment completion. All cases were treated on a Novalis linac with ExacTrac positioning system and Exact Couch. The two image sets were compared with the correctional shifts measured by ExacTrac 6D auto-fusion. The shift differences were considered patient motion within the frameless mask and were used to evaluate its effectiveness for immobilization. Two-tailed paired t-test was applied for significance comparison. Results: The correctional shifts (mean±STD, median) of pre-and post-treatment images were 0.33±0.27mm, 0.26mm and 0.34±0.27mm, 0.23mm (p=0.740) in lateral direction; 0.32±0.29mm, 0.22mm and 0.48±0.30mm, 0.50mm (p=0.012) in longitudinal direction; 0.31±0.22mm, 0.24mm and 0.33±0.21mm, 0.36mm (p=0.623) in vertical direction. The radial correctional shifts (mean±STD, median) of pre -and post-treatment images were 0.60±0.38mm, 0.45mm and 0.75±0.31mm, 0.66mm (p=0.033). The shift differences (mean±STD, median, maximum) were 0.35±0.28mm, 0.3mm, 1.05mm, 0.34±0.28mm, 0.3mm, 1.00mm, 0.24±0.15mm, 0.21mm, 0.60mm and 0.61±0.32mm, 0.57mm, 1.40mm in lateral, longitudinal, vertical and radial direction, respectively. Two shifts greater than 1 mm (1.06mm and 1.02mm) were acquired from post-treatment images. However, the shift differences were only 0.09 and 0.19mm for these two shifts. Two patients with shift differences greater than 1mm (1.05 and 1.04mm) were observed and didn’t coincide with those two who had post-correctional shifts greater than 1mm. Conclusion: Image-guided SRS allowed us to set up patients with sub

  16. Feasibility of an online adaptive replanning method for cranial frameless intensity-modulated radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Juan Francisco, E-mail: jfcdrr@gmail.com [Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona (Spain); San José, Sol [Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona (Spain); Garrido, LLuís [Institut de Ciències del Cosmos i Departament ECM, Universitat de Barcelona, Barcelona (Spain); Puertas, Enrique; Moragues, Sandra; Pozo, Miquel [Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona (Spain); Casals, Joan, E-mail: jfcdrr@yahoo.es [Departamento de Oncología Radioterápica, Hospital Quirón, Barcelona (Spain)

    2013-10-01

    To introduce an approach for online adaptive replanning (i.e., dose-guided radiosurgery) in frameless stereotactic radiosurgery, when a 6-dimensional (6D) robotic couch is not available in the linear accelerator (linac). Cranial radiosurgical treatments are planned in our department using intensity-modulated technique. Patients are immobilized using thermoplastic mask. A cone-beam computed tomography (CBCT) scan is acquired after the initial laser-based patient setup (CBCT{sub setup}). The online adaptive replanning procedure we propose consists of a 6D registration-based mapping of the reference plan onto actual CBCT{sub setup}, followed by a reoptimization of the beam fluences (“6D plan”) to achieve similar dosage as originally was intended, while the patient is lying in the linac couch and the original beam arrangement is kept. The goodness of the online adaptive method proposed was retrospectively analyzed for 16 patients with 35 targets treated with CBCT-based frameless intensity modulated technique. Simulation of reference plan onto actual CBCT{sub setup}, according to the 4 degrees of freedom, supported by linac couch was also generated for each case (4D plan). Target coverage (D99%) and conformity index values of 6D and 4D plans were compared with the corresponding values of the reference plans. Although the 4D-based approach does not always assure the target coverage (D99% between 72% and 103%), the proposed online adaptive method gave a perfect coverage in all cases analyzed as well as a similar conformity index value as was planned. Dose-guided radiosurgery approach is effective to assure the dose coverage and conformity of an intracranial target volume, avoiding resetting the patient inside the mask in a “trial and error” way so as to remove the pitch and roll errors when a robotic table is not available.

  17. Use of frameless intrauterine devices and systems in young nulliparous and adolescent women: results of a multicenter study

    OpenAIRE

    Wildemeersch D; Jandi S; Pett A; Nolte K; Hasskamp T; Vrijens M

    2014-01-01

    Dirk Wildemeersch,1 Sohela Jandi,2 Ansgar Pett,2 Kilian Nolte,3 Thomas Hasskamp,4 Marc Vrijens5 1Gynecological Outpatient Clinic and IUD Training Center, Ghent, Belgium; 2Gynecological Outpatient Clinic, Berlin, 3Gynecological Outpatient Clinic, Uetze, 4GynMünster, Münster, Germany; 5Gynecological Outpatient Clinic, Ghent, Belgium Background: The purpose of this study was to provide additional data on the experience with frameless copper and levonorgestrel (LNG) intrauterin...

  18. Clinical Evaluation of a Robotic 6-Degree of Freedom Treatment Couch for Frameless Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Gevaert, Thierry, E-mail: thierry.gevaert@uzbrussel.be [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium); Verellen, Dirk; Engels, Benedikt; Depuydt, Tom; Heuninckx, Karina; Tournel, Koen; Duchateau, Michael; Reynders, Truus; De Ridder, Mark [Department of Radiotherapy, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels (Belgium)

    2012-05-01

    Purpose: To evaluate the added value of 6-degree of freedom (DOF) patient positioning with a robotic couch compared with 4DOF positioning for intracranial lesions and to estimate the immobilization characteristics of the BrainLAB frameless mask (BrainLAB AG, Feldkirchen, Germany), more specifically, the setup errors and intrafraction motion. Methods and Materials: We enrolled 40 patients with 66 brain metastases treated with frameless stereotactic radiosurgery and a 6DOF robotic couch. Patient positioning was performed with the BrainLAB ExacTrac stereoscopic X-ray system. Positioning results were collected before and after treatment to assess patient setup error and intrafraction motion. Existing treatment planning data were loaded and simulated for 4DOF positioning and compared with the 6DOF positioning. The clinical relevance was analyzed by means of the Paddick conformity index and the ratio of prescribed isodose volume covered with 4DOF to that obtained with the 6DOF positioning. Results: The mean three-dimensional setup error before 6DOF correction was 1.91 mm (SD, 1.25 mm). The rotational errors were larger in the longitudinal (mean, 0.23 Degree-Sign ; SD, 0.82 Degree-Sign ) direction compared with the lateral (mean, -0.09 Degree-Sign ; SD, 0.72 Degree-Sign ) and vertical (mean, -0.10 Degree-Sign ; SD, 1.03 Degree-Sign ) directions (p < 0.05). The mean three-dimensional intrafraction shift was 0.58 mm (SD, 0.42 mm). The mean intrafractional rotational errors were comparable for the vertical, longitudinal, and lateral directions: 0.01 Degree-Sign (SD, 0.35 Degree-Sign ), 0.03 Degree-Sign (SD, 0.31 Degree-Sign ), and -0.03 Degree-Sign (SD, 0.33 Degree-Sign ), respectively. The mean conformity index decreased from 0.68 (SD, 0.08) (6DOF) to 0.59 (SD, 0.12) (4DOF) (p < 0.05). A loss of prescribed isodose coverage of 5% (SD, 0.08) was found with the 4DOF positioning (p < 0.05). Half a degree for longitudinal and lateral rotations can be identified as a threshold

  19. Clinical evaluation of a robotic 6-degree of freedom treatment couch for frameless radiosurgery.

    Science.gov (United States)

    Gevaert, Thierry; Verellen, Dirk; Engels, Benedikt; Depuydt, Tom; Heuninckx, Karina; Tournel, Koen; Duchateau, Michael; Reynders, Truus; De Ridder, Mark

    2012-05-01

    To evaluate the added value of 6-degree of freedom (DOF) patient positioning with a robotic couch compared with 4DOF positioning for intracranial lesions and to estimate the immobilization characteristics of the BrainLAB frameless mask (BrainLAB AG, Feldkirchen, Germany), more specifically, the setup errors and intrafraction motion. We enrolled 40 patients with 66 brain metastases treated with frameless stereotactic radiosurgery and a 6DOF robotic couch. Patient positioning was performed with the BrainLAB ExacTrac stereoscopic X-ray system. Positioning results were collected before and after treatment to assess patient setup error and intrafraction motion. Existing treatment planning data were loaded and simulated for 4DOF positioning and compared with the 6DOF positioning. The clinical relevance was analyzed by means of the Paddick conformity index and the ratio of prescribed isodose volume covered with 4DOF to that obtained with the 6DOF positioning. The mean three-dimensional setup error before 6DOF correction was 1.91 mm (SD, 1.25 mm). The rotational errors were larger in the longitudinal (mean, 0.23°; SD, 0.82°) direction compared with the lateral (mean, -0.09°; SD, 0.72°) and vertical (mean, -0.10°; SD, 1.03°) directions (p errors were comparable for the vertical, longitudinal, and lateral directions: 0.01° (SD, 0.35°), 0.03° (SD, 0.31°), and -0.03° (SD, 0.33°), respectively. The mean conformity index decreased from 0.68 (SD, 0.08) (6DOF) to 0.59 (SD, 0.12) (4DOF) (p error and intrafraction motions need to be evaluated and corrected for. The 6DOF patient positioning with a 6DOF robotic couch to correct translational and rotational setup errors improves target positioning with respect to treatment isocenter, which is in direct relation with the clinical outcome, compared with the 4DOF positioning. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. A miniaturized imaging system for optical guided surgery of head and neck cancer

    Science.gov (United States)

    Atallah, Ihab; Milet, Clément; Dorval, Paul; Gayet, Pascal; Rizo, Philippe; Henry, Maxime; Reyt, Emile; Josserand, Véronique; Hurbin, Amandine; Righini, Christian; Coll, Jean-Luc

    2015-03-01

    Near-infrared fluorescence image-guided surgery, FIGS, has lately shown a huge potential in oncologic and lymphatic related surgeries. In some indications such as liver or heart surgery, fluorescence-reachable anatomic structures are limited by the access to the surgical field. Nevertheless, most of the systems available on the market are too large to image the sides of cavities. Small devices are clearly required to improve workability of fluorescence imaging systems. The current work describes the evaluation of Fluostick a CE med certified instrument dedicated to narrow area imaging. This small size device is made of an optical head connected to a control box. We tested this instrumentation at the preclinical level for the optical-guided surgery of head and neck tumors.

  1. The geometric accuracy of frameless stereotactic radiosurgery using a 6D robotic couch system

    Energy Technology Data Exchange (ETDEWEB)

    Takakura, T; Nakata, M; Yano, S; Fujimoto, T [Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto (Japan); Mizowaki, T; Miyabe, Y; Nakamura, M; Hiraoka, M [Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan)], E-mail: toru1@kuhp.kyoto-u.ac.jp

    2010-01-07

    The aim of this paper is to assess the overall geometric accuracy of the Novalis system using the Robotic Tilt Module in terms of the uncertainty in frameless stereotactic radiotherapy. We analyzed the following three metrics: (1) the correction accuracy of the robotic couch, (2) the uncertainty of the isocenter position with gantry and couch rotation, and (3) the shift in position between the isocenter and central point detected with the ExacTrac x-ray system. Based on the concept of uncertainty, the overall accuracy was calculated from these values. The accuracy in positional correction with the robotic couch was 0.07 {+-} 0.22 mm, the positional shift of the isocenter associated with gantry rotation was 0.35 mm, the positional shift of the isocenter associated with couch rotation was 0.38 mm and the difference in position between the isocenter and the ExacTrac x-ray system was 0.30 mm. The accuracy of intracranial stereotactic radiosurgery with the Novalis system in our clinic was 0.31 {+-} 0.77 mm. The overall geometric accuracy based on the concept of uncertainty was 0.31 {+-} 0.77 mm, which is within the tolerance given in the American Association of Physicists in Medicine report no. 54.

  2. Accurate external localization of the left frontal cortex in dogs by using pointer based frameless neuronavigation

    Directory of Open Access Journals (Sweden)

    Robrecht Dockx

    2017-07-01

    Full Text Available Background In humans, non-stereotactic frameless neuronavigation systems are used as a topographical tool for non-invasive brain stimulation methods such as Transcranial Magnetic Stimulation (TMS. TMS studies in dogs may provide treatment modalities for several neuropsychological disorders in dogs. Nevertheless, an accurate non-invasive localization of a stimulation target has not yet been performed in this species. Hypothesis This study was primarily put forward to externally locate the left frontal cortex in 18 healthy dogs by means of a human non-stereotactic neuronavigation system. Secondly, the accuracy of the external localization was assessed. Animals A total of 18 healthy dogs, drawn at random from the research colony present at the faculty of Veterinary Medicine (Ghent University, were used. Methods Two sets of coordinates (X, Y, Z and X″, Y″, Z″ were compared on each dog their tomographical dataset. Results The non-stereotactic neuronavigation system was able to externally locate the frontal cortex in dogs with accuracy comparable with human studies. Conclusion and clinical importance This result indicates that a non-stereotactic neuronavigation system can accurately externally locate the left frontal cortex and paves the way to use guided non-invasive brain stimulation methods as an alternative treatment procedure for neurological and behavioral disorders in dogs. This technique could, in analogy with human guided non-invasive brain stimulation, provide a better treatment outcome for dogs suffering from anxiety disorders when compared to its non-guided alternative.

  3. The geometric accuracy of frameless stereotactic radiosurgery using a 6D robotic couch system.

    Science.gov (United States)

    Takakura, T; Mizowaki, T; Nakata, M; Yano, S; Fujimoto, T; Miyabe, Y; Nakamura, M; Hiraoka, M

    2010-01-07

    The aim of this paper is to assess the overall geometric accuracy of the Novalis system using the Robotic Tilt Module in terms of the uncertainty in frameless stereotactic radiotherapy. We analyzed the following three metrics: (1) the correction accuracy of the robotic couch, (2) the uncertainty of the isocenter position with gantry and couch rotation, and (3) the shift in position between the isocenter and central point detected with the ExacTrac x-ray system. Based on the concept of uncertainty, the overall accuracy was calculated from these values. The accuracy in positional correction with the robotic couch was 0.07 +/- 0.22 mm, the positional shift of the isocenter associated with gantry rotation was 0.35 mm, the positional shift of the isocenter associated with couch rotation was 0.38 mm and the difference in position between the isocenter and the ExacTrac x-ray system was 0.30 mm. The accuracy of intracranial stereotactic radiosurgery with the Novalis system in our clinic was 0.31 +/- 0.77 mm. The overall geometric accuracy based on the concept of uncertainty was 0.31 +/- 0.77 mm, which is within the tolerance given in the American Association of Physicists in Medicine report no. 54.

  4. The Frameless Copper IUD (GyneFix) and the TCu380A IUD : Results of an 8-year Multicenter Randomized Comparative Trial

    OpenAIRE

    Meirik, O.; Rowe, P J; Peregoudov, A.; Piaggio, G; Petzold, M.

    2009-01-01

    BACKGROUND: Clinical performance of the frameless copper IUD (GyneFix), designed to reduce side effects related to the frame of conventional IUDs, and TCu380A was compared. STUDY DESIGN: Randomized Multicenter randomized comparative trial. Parous women requesting and eligible to use IUD were admitted in 21 centers in eight countries in 1989-1993 and followed-up for up to 8 years. RESULTS: Two thousand twenty-seven women were randomized to the frameless IUD and 2036 to TCu380A; 43 insertions o...

  5. Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinmin; Belcher, Andrew H.; Grelewicz, Zachary; Wiersma, Rodney D., E-mail: rwiersma@uchicago.edu [Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-06-15

    Purpose: To develop a control system to correct both translational and rotational head motion deviations in real-time during frameless stereotactic radiosurgery (SRS). Methods: A novel feedback control with a feed-forward algorithm was utilized to correct for the coupling of translation and rotation present in serial kinematic robotic systems. Input parameters for the algorithm include the real-time 6DOF target position, the frame pitch pivot point to target distance constant, and the translational and angular Linac beam off (gating) tolerance constants for patient safety. Testing of the algorithm was done using a 4D (XY Z + pitch) robotic stage, an infrared head position sensing unit and a control computer. The measured head position signal was processed and a resulting command was sent to the interface of a four-axis motor controller, through which four stepper motors were driven to perform motion compensation. Results: The control of the translation of a brain target was decoupled with the control of the rotation. For a phantom study, the corrected position was within a translational displacement of 0.35 mm and a pitch displacement of 0.15° 100% of the time. For a volunteer study, the corrected position was within displacements of 0.4 mm and 0.2° over 98.5% of the time, while it was 10.7% without correction. Conclusions: The authors report a control design approach for both translational and rotational head motion correction. The experiments demonstrated that control performance of the 4D robotic stage meets the submillimeter and subdegree accuracy required by SRS.

  6. Construction and Evaluation of an Ultra Low Latency Frameless Renderer for VR.

    Science.gov (United States)

    Friston, Sebastian; Steed, Anthony; Tilbury, Simon; Gaydadjiev, Georgi

    2016-04-01

    Latency - the delay between a user's action and the response to this action - is known to be detrimental to virtual reality. Latency is typically considered to be a discrete value characterising a delay, constant in time and space - but this characterisation is incomplete. Latency changes across the display during scan-out, and how it does so is dependent on the rendering approach used. In this study, we present an ultra-low latency real-time ray-casting renderer for virtual reality, implemented on an FPGA. Our renderer has a latency of ~1 ms from 'tracker to pixel'. Its frameless nature means that the region of the display with the lowest latency immediately follows the scan-beam. This is in contrast to frame-based systems such as those using typical GPUs, for which the latency increases as scan-out proceeds. Using a series of high and low speed videos of our system in use, we confirm its latency of ~1 ms. We examine how the renderer performs when driving a traditional sequential scan-out display on a readily available HMO, the Oculus Rift OK2. We contrast this with an equivalent apparatus built using a GPU. Using captured human head motion and a set of image quality measures, we assess the ability of these systems to faithfully recreate the stimuli of an ideal virtual reality system - one with a zero latency tracker, renderer and display running at 1 kHz. Finally, we examine the results of these quality measures, and how each rendering approach is affected by velocity of movement and display persistence. We find that our system, with a lower average latency, can more faithfully draw what the ideal virtual reality system would. Further, we find that with low display persistence, the sensitivity to velocity of both systems is lowered, but that it is much lower for ours.

  7. Fast vision through frameless event-based sensing and convolutional processing: application to texture recognition.

    Science.gov (United States)

    Perez-Carrasco, Jose Antonio; Acha, Begona; Serrano, Carmen; Camunas-Mesa, Luis; Serrano-Gotarredona, Teresa; Linares-Barranco, Bernabe

    2010-04-01

    Address-event representation (AER) is an emergent hardware technology which shows a high potential for providing in the near future a solid technological substrate for emulating brain-like processing structures. When used for vision, AER sensors and processors are not restricted to capturing and processing still image frames, as in commercial frame-based video technology, but sense and process visual information in a pixel-level event-based frameless manner. As a result, vision processing is practically simultaneous to vision sensing, since there is no need to wait for sensing full frames. Also, only meaningful information is sensed, communicated, and processed. Of special interest for brain-like vision processing are some already reported AER convolutional chips, which have revealed a very high computational throughput as well as the possibility of assembling large convolutional neural networks in a modular fashion. It is expected that in a near future we may witness the appearance of large scale convolutional neural networks with hundreds or thousands of individual modules. In the meantime, some research is needed to investigate how to assemble and configure such large scale convolutional networks for specific applications. In this paper, we analyze AER spiking convolutional neural networks for texture recognition hardware applications. Based on the performance figures of already available individual AER convolution chips, we emulate large scale networks using a custom made event-based behavioral simulator. We have developed a new event-based processing architecture that emulates with AER hardware Manjunath's frame-based feature recognition software algorithm, and have analyzed its performance using our behavioral simulator. Recognition rate performance is not degraded. However, regarding speed, we show that recognition can be achieved before an equivalent frame is fully sensed and transmitted.

  8. Translational and rotational intra- and inter-fractional errors in patient and target position during a short course of frameless stereotactic body radiotherapy

    DEFF Research Database (Denmark)

    Josipovic, Mirjana; Persson, Gitte Fredberg; Logadottir, Ashildur;

    2012-01-01

    Implementation of cone beam computed tomography (CBCT) in frameless stereotactic body radiotherapy (SBRT) of lung tumours enables setup correction based on tumour position. The aim of this study was to compare setup accuracy with daily soft tissue matching to bony anatomy matching and evaluate...

  9. VarioGuide: a new frameless image-guided stereotactic system--accuracy study and clinical assessment.

    Science.gov (United States)

    Ringel, Florian; Ingerl, Dominik; Ott, Stephanie; Meyer, Bernhard

    2009-05-01

    VarioGuide (BrainLAB AG, Feldkirchen, Germany) is a new system for frameless image-guided stereotaxy. In the present study, we aimed to assess target point accuracy in a laboratory setting and the clinical feasibility of the system. Using the phantom of our frame-based stereotactic system (Riechert-Mundinger; Inomed Medizintechnik GmbH, Teningen, Germany), target points were approached from different angles with the frameless system. Target point deviation in the x, y, and z planes was assessed. Furthermore, patients harboring intracranial lesions were diagnostically biopsied using VarioGuide. Phantom-based accuracy measurements yielded a mean target point deviation of 0.7 mm. Between February 2007 and April 2008, 27 patients were diagnostically biopsied. Lesion volumes ranged from 0.2 to 117.6 cm3, trajectory length ranged from 25.3 to 64.1 mm, and the diagnostic yield was 93%. Concluding from the phantom measurements with ideal image-object registration, assumed spherical lesions with a volume of 0.524 cm can be biopsied with 100% target localization. Early clinical data revealed VarioGuide to be safe and accurate for lesions of 0.2 cm3 and larger. Thereby, the system seems feasible for the biopsy of most intracranial lesions.

  10. Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

    Energy Technology Data Exchange (ETDEWEB)

    Wen, N., E-mail: nwen1@hfhs.org; Snyder, K. C.; Qin, Y.; Li, H.; Siddiqui, M. S.; Chetty, I. J. [Department of Radiation Oncology, Henry Ford Health System, 2799 West Brand Boulevard, Detroit, Michigan 48202 (United States); Scheib, S. G.; Schmelzer, P. [Varian Medical System, Täfernstrasse 7, Dättwil AG 5405 (Switzerland)

    2016-05-15

    Purpose: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. Methods: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, “snap-shot” planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. Results: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2 mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. Conclusions: The authors’ experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.

  11. Dosimetric consequences of translational and rotational errors in frame-less image-guided radiosurgery

    Directory of Open Access Journals (Sweden)

    Guckenberger Matthias

    2012-04-01

    Full Text Available Abstract Background To investigate geometric and dosimetric accuracy of frame-less image-guided radiosurgery (IG-RS for brain metastases. Methods and materials Single fraction IG-RS was practiced in 72 patients with 98 brain metastases. Patient positioning and immobilization used either double- (n = 71 or single-layer (n = 27 thermoplastic masks. Pre-treatment set-up errors (n = 98 were evaluated with cone-beam CT (CBCT based image-guidance (IG and were corrected in six degrees of freedom without an action level. CBCT imaging after treatment measured intra-fractional errors (n = 64. Pre- and post-treatment errors were simulated in the treatment planning system and target coverage and dose conformity were evaluated. Three scenarios of 0 mm, 1 mm and 2 mm GTV-to-PTV (gross tumor volume, planning target volume safety margins (SM were simulated. Results Errors prior to IG were 3.9 mm ± 1.7 mm (3D vector and the maximum rotational error was 1.7° ± 0.8° on average. The post-treatment 3D error was 0.9 mm ± 0.6 mm. No differences between double- and single-layer masks were observed. Intra-fractional errors were significantly correlated with the total treatment time with 0.7mm±0.5mm and 1.2mm±0.7mm for treatment times ≤23 minutes and >23 minutes (p5% in 14% of the patients. A 1 mm safety margin fully compensated intra-fractional patient motion. Conclusions IG-RS with online correction of translational errors achieves high geometric and dosimetric accuracy. Intra-fractional errors decrease target coverage and conformity unless compensated with appropriate safety margins.

  12. SU-F-T-647: Linac-Based Stereotactic Radiosurgery (SRS) in the Treatment of Trigeminal Neuralgia: Detailed Description of SRS Procedural Technique and Reported Clinical Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Pokhrel, D; Sood, S; Badkul, R; Jiang, H; Stepp, T; Camarata, P; Wang, F [University of Kansas Hospital, Kansas City, KS (United States)

    2016-06-15

    Purpose: SRS is an effective non-invasive alternative treatment modality with minimal-toxicity used to treat patients with medically/surgically refractory trigeminal neuralgia root(TNR) or those who may not tolerate surgical intervention. We present our linac-based SRS procedure for TNR treatment and simultaneously report our clinical outcomes. Methods: Twenty-eight TNR-patients treated with frame-based SRS at our institution (2009–2015) with a single-fraction point-dose of 60-80Gy to TNR were included in this IRB-approved study. Experienced neurosurgeon and radiation oncologist delineated the TNR on 1.0mm thin 3D-FIESTA-MRI that was co-registered with 0.7mm thin planning-CT. Treatment plans were generated in iPlan (BrainLAB) with a 4-mm diameter cone using 79 arcs with differential-weighting for Novalis-TX 6MV-SRS(1000MU/min) beam and optimized to minimize brainstem dose. Winston-Lutz test was performed before each treatment delivery with sub-millimeter isocenter accuracy. Quality assurance of frame placement was maintained by helmet-bobble-measurement before simulation-CT and before patient setup at treatment couch. OBI-CBCT scan was performed for patient setup verification without applying shifts. On clinical follow up, treatment response was assessed using Barrow Neurological Institute Pain Intensity Score(BNI-score:I–V). Results: 26/28 TNR-patients (16-males/10-females) who were treated with following single-fraction point-dose to isocenter: 80Gy(n=22),75Gy(n=1),70Gy(n=2) and 60Gy(n=1, re-treatment) were followed up. Median follow-up interval was 8.5-months (ranged:1–48.5months). Median age was 70-yr (ranged:43–93-yr). Right/left TNR ratio was 15/11. Delivered total # of average MUs was 19034±1204. Average beam-on-time: 19.0±1.3min. Brainstem max-dose and dose to 0.5cc were 13.3±2.4Gy (ranged:8.1–16.5Gy) and 3.6±0.4Gy (ranged:3.0–4.9Gy). On average, max-dose to optic-apparatus was ≤1.2Gy. Mean value of max-dose to eyes/lens was 0.26Gy/0.11Gy

  13. SU-E-T-355: A Comparative Study of Robotic and Linac-Based Stereotactitc Body Radiation Therapy for Lumbar Spinal Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, E; Monterroso, M; Couto, M; Ly, B; Mihaylov, I [UniversityMiami, Miami, FL (United States)

    2014-06-01

    Purpose: Dosimetrically compare CyberKnife (CK) and linac-based (LB) stereotactic body radiotherapy (SBRT) plans for lumbar spine. Methods: Ten patient plans with lumbar spine tumors treated with CK were selected and retrospectively optimized using three techniques: CK, volumetric modulated arc (VMAT, three arcs), and 9-field-intensity modulated radiotherapy (IMRT). For the LB plans, the target volume was expanded by 1mm to accommodate additional uncertainty in patient positioning. All plans were optimized to a prescription dose of 27Gy in 3 fractions covering 90% of the PTV. If the dose constraints to the cauda equina (cauda) were not met, the prescription dose was lowered to 24Gy. Parameters evaluated included Paddick Conformity-Index (CI) and Gradient-Index (GI). A two-tailed paired t-test was used to establish statistically significant differences in cauda doses. Results: Target volumes for LB plans were on average 38% larger. In terms of the indices, the closer the index values to unity the steeper the dose falloff and the higher the dose conformity to the target. The results showed that LB plans were in general statistically superior to CK plans. The IMRT plan showed the best average gradient index of 2.995, with VMAT and CK GI values of 3.699 and 5.476, respectively. Similarly, the same trend occurs with the average CI results: 0.821, 0.814, and 0.758, corresponding to IMRT, VMAT, and CK. Notably, in one CK plan the target dose was reduced to 24Gy to meet cauda constraints. Additionally, there was a statistically significant dose difference for the cauda between the CK and LB plans. Conclusion: This study demonstrates that LB plans for lumbar spine SBRT can be as effective or even better than CK plans. Despite the expansion of the target volume, the LB plans did not demonstrate dosimetric inferiority. The LB plans Resultin 2-to-3 fold decrease of treatment time.

  14. Optical Guiding of Trapped Atoms by a Blue-Detuned Hollow Laser Beam in the Horizontal Direction

    Institute of Scientific and Technical Information of China (English)

    JIANG Kai-Jun; LI Ke; WANG Jin; ZHAN Ming-Sheng

    2005-01-01

    @@ Optical guiding of 85 Rb atoms in a magneto-optical trap (MOT) by a blue-detuned horizontal hollow laser beam is demonstrated experimentally. The guiding efficiency and the velocity distribution of the guided atoms are found to have strong dependence on the detuning of the guiding laser. In particular, the optimum guiding occurs when the blue detuning of the hollow laser beam is approximately equal to the hyperfine structure splitting of the 85Rb ground states, in good agreement with the theoretical analysis based on a three-level model.

  15. Precision intrauterine contraception may significantly increase continuation of use: a review of long-term clinical experience with frameless copper-releasing intrauterine contraception devices

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2013-04-01

    Full Text Available Dirk Wildemeersch,1 Ansgar Pett,2 Sohela Jandi,2 Thomas Hasskamp,3 Patrick Rowe,4 Marc Vrijens5 1Gynecological Outpatient Clinic and IUD Training Center, Ghent, Belgium; 2Gynecological Outpatient Clinic, Berlin, Germany; 3Gynecological Outpatient Clinic, Münster, Germany; 4Formely IUD Research Group at the UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, Geneva, Switzerland; 5Gynecological Outpatient Clinic, Ghent, Belgium Objective: The purpose of this paper is to review the experience with the frameless, anchored, GyneFix copper-releasing intrauterine contraceptive devices (IUCDs/IUDs (Contrel Europe, Belgium, and to demonstrate their high acceptability and low rate of discontinuation of use, which could contribute to current efforts that aim to reduce radically the high number of unintended pregnancies and induced abortions, particularly in young women. Materials and methods: This paper is based on studies that examined the differences in uterine volume and cavity size, related to age and parity, and on original clinical research data and practical experience with frameless copper IUDs, as well as on literature data on the IUD–endometrial cavity relationship of conventional IUDs, with special reference to side effects and user discontinuation. Results: The mean transverse diameter in nulliparous and parous women is significantly less than the length of the transverse arm of the TCu380A IUD (ParaGard, Duramed, NY, USA or the levonorgestrel intrauterine system (Mirena, Bayer, Germany. Small, frameless, flexible, and unidimensional copper IUDs appear to be well tolerated, with less impact on menstrual bleeding, resulting in low discontinuation rates when compared with standard-size conventional IUDs, which often result in increased expulsion rates, complaints of pain and erratic or increased menstrual bleeding, and subsequent high rates of

  16. INTER- AND INTRAFRACTION MOTION FOR STEREOTACTIC RADIOSURGERY IN DOGS AND CATS USING A MODIFIED BRAINLAB FRAMELESS STEREOTACTIC MASK SYSTEM.

    Science.gov (United States)

    Dieterich, Sonja; Zwingenberger, Allison; Hansen, Katherine; Pfeiffer, Isabella; Théon, Alain; Kent, Michael S

    2015-01-01

    Precise and accurate patient positioning is necessary when doing stereotactic radiosurgery (SRS) to ensure adequate dosing to the tumor and sparing of normal tissues. This prospective cross-sectional study aimed to assess feasibility of a commercially available modified frameless SRS positioning system for use in veterinary radiotherapy patients with brain tumors. Fifty-one dogs and 12 cats were enrolled. Baseline and verification CT images were acquired. The verification CT images from 32 dogs and five cats had sufficient images for fusion to baseline CT images. A rigid box-based fusion was performed to determine interfraction motion. Forty-eight dogs and 11 cats were assessed for intrafraction motion by cine CT. Seventy percent of dogs and 60% of cats had interfraction 3D vector translational shifts >1 mm, with mean values of 1.9 mm in dogs, and 1.8 mm in cats. In dogs muscle wasting was weakly correlated with translational shifts. The maximum angular interfraction motion observed was 6.3° (roll), 3.5° (pitch), and 3.3° (yaw). There was no correlation between angular interfraction motion and weight, brachycephaly, or muscle wasting. Fifty-seven percent of dogs and 50% of cats had respiration-related intrafraction motion. Of these, 4.5% of dogs and 10% of cats had intrafraction motion >1 mm. This study demonstrates the modified Brainlab system is feasible for SRS in dogs and cats. The smaller cranial size and difference in anatomy increases setup uncertainty in some animals beyond limits usually accepted in SRS. Image-guided positioning is recommended to achieve clinically acceptable setup accuracy (<1 mm) for SRS. © 2015 American College of Veterinary Radiology.

  17. {open_quotes}Optical guiding{close_quotes} limits on extraction efficiencies of single-pass, tapered wiggler amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, W.M. [Lawrence Berkeley Lab., CA (United States)

    1995-12-31

    Single-pass, tapered wiggler amplifiers have an attractive feature of being able, in theory at least, of extracting a large portion of the electron beam energy into light. In circumstances where an optical FEL`s wiggler length is significantly longer than the Rayleigh length Z{sub R} corresponding to the electron beam radius, diffraction losses must be controlled via the phenomenon of {open_quotes}optical guiding{close_quotes}. Since the strength of the guiding depends upon the effective refractive index {eta}{sub r} exceeding one, and since ({eta}{sub r}-1) is inversely proportional to the optical electric field, there is a natural {open_quotes}limiting{close_quotes} mechanism to the on-axis field strength and thus the rate at which energy may be extracted from the electron beam. In particular, the extraction efficiency for a prebunched beam asymptotically grows linearly with z rather than quadratically. We present analytical and numerical simulation results concerning this behavior and discuss its applicability to various FEL designs including oscillator/amplifier-radiator configurations.

  18. Comparison of the air-Q intubating laryngeal airway and the cobra perilaryngeal airway as conduits for fiber optic-guided intubation in pediatric patients

    Directory of Open Access Journals (Sweden)

    Karim K Girgis

    2014-01-01

    Full Text Available Background: One of the methods proposed in cases of difficult airway management in children is using a supraglottic airway device as a conduit for tracheal intubation. The aim of this study was to compare the efficacy of the Air-Q Intubating Laryngeal Airway (Air-Q and the Cobra Perilaryngeal Airway (CobraPLA to function as a conduit for fiber optic-guided tracheal intubation in pediatric patients. Materials and Methods: A total of 60 children with ages ranging from 1 to 6 years, undergoing elective surgery, were randomized to have their airway managed with either an Air-Q or CobraPLA. Outcomes recorded were the success rate, time and number of attempts required for fiber optic-guided intubation and the time required for device removal after intubation. We also recorded airway leak pressure (ALP, fiber optic grade of glottic view and occurrence of complications. Results: Both devices were successfully inserted in all patients. The intubation success rate was comparable with the Air-Q and the CobraPLA (96.7% vs. 90%, as was the first attempt success rate (90% vs. 80%. The intubation time was significantly longer with the CobraPLA (29.5 ± 10.9 s vs. 23.2 ± 9.8 s; P < 0.05, but the device removal time was comparable in the two groups. The CobraPLA showed a significantly higher ALP (20.8 ± 5.2 cmH 2 O vs. 16.3 ± 4.5 cmH 2 O; P < 0.001, but the fiber optic grade of glottic view was comparable with the two devices. The CobraPLA was associated with a significantly higher incidence of blood staining of the device on removal and post-operative sore throat. Conclusion: Both the Air-Q and CobraPLA can be used effectively as a conduit for fiber optic-guided tracheal intubation in children. However, the Air-Q proved to be superior due to a shorter intubation time and less airway morbidity compared with the CobraPLA.

  19. Setup verification in linac-based radiosurgery.

    Science.gov (United States)

    Falco, T; Lachaine, M; Poffenbarger, B; Podgorsak, E B; Fallone, B G

    1999-09-01

    A semi-automatic technique for the direct setup alignment of radiosurgical circular fields from an isocentric linac to treatment room laser cross-hairs is described. Alignment is achieved by acquiring images of the treatment room positioning laser cross-hairs superimposed on the radiosurgical circular field image. An alignment algorithm calculates the center of the radiosurgical field image as well as the intersection of the laser cross-hairs. This determines any alignment deviations and the information is then used to translate the radiosurgical collimator to its correct aligned position. Two detectors, each being sensitive to the lasers and ionizing radiation, were used to acquire the radiation/laser images. The first detector consists of a 0.3-mm-thick layer of photoconducting a-Se deposited on a 1.5-mm-thick copper plate and the second is film. The algorithm and detector system can detect deviations with a precision of approximately 0.04 mm. A device with gyroscopic degrees of freedom was built in order to firmly hold the detector at any orientation perpendicular to the radiosurgical beam axis. This device was used in conjunction with our alignment algorithm to quantify the isocentric sphere relative to the treatment room lasers over all gantry and couch angles used in dynamic stereotactic radiosurgery.

  20. High-quality Linac-based Stereotactic Body Radiation Therapy with Flattening Filter Free Beams and Volumetric Modulated Arc Therapy for Low-Intermediate Risk Prostate Cancer. A Mono-institutional Experience with 90 Patients.

    Science.gov (United States)

    D'Agostino, G; Franzese, C; De Rose, F; Franceschini, D; Comito, T; Villa, E; Alongi, F; Liardo, R; Tomatis, S; Navarria, P; Mancosu, P; Reggiori, G; Cozzi, L; Scorsetti, M

    2016-12-01

    The aim of this phase II study was to evaluate the efficacy and toxicity of stereotactic body radiotherapy in patients with low or intermediate risk prostate cancer. Biopsy-confirmed prostate cancer patients were enrolled, provided that they had the following characteristics: initial prostate-specific antigen (PSA) ≤ 20 ng/ml, Gleason Score free beams. Toxicity was recorded according to CTCAE criteria v4.0. Biochemical failure was calculated according to the Phoenix definition. The Expanded Prostate Cancer Index Composite questionnaire was used to record health-related quality of life. Between December 2011 and March 2015, 90 patients were enrolled (53 low risk, 37 intermediate risk). The median age was 71 years (range 48-82). In total, 58 (64.5%) of the patients had Gleason Score=6, the remaining had Gleason Score=7.The median initial PSA was 6.9 ng/ml (range 2.7-17.0). Acute toxicity was mild, with 32.2 patients presenting grade 1 urinary toxicity and 32.2% of patients presenting grade 2 urinary toxicity, mainly represented by urgency, dysuria and stranguria. Rectal grade 1 toxicity was found in 15.5% of patients, whereas grade 2 toxicity was recorded in 6.6% of patients. Regarding late toxicity, grade 1 proctitis was recorded in 11.1% of patients and grade 1 urinary in 38.8%; only two events of grade 2 urinary toxicity were observed (transient urethral stenosis, resolved by a 24 h catheterisation). At a median follow-up of 27 months (6-62 months) only two intermediate risk patients experienced a biochemical failure. Health-related quality of life revealed a slight worsening in all the domains during treatment, with a return to baseline 3 months after treatment. Stereotactic body radiotherapy delivered using linac-based flattening filter free volumetric modulated arc radiotherapy in low and intermediate risk prostate cancer patients is associated with mild toxicity profiles and good patient-reported quality of life. Copyright © 2016 The Royal College of

  1. Diagnostic yield and morbidity by neuronavigation-guided frameless stereotactic biopsy using magnetic resonance imaging and by frame-based computed tomography-guided stereotactic biopsy

    Directory of Open Access Journals (Sweden)

    Masamitsu Nishihara

    2014-01-01

    Full Text Available Background: We compared the diagnostic yield and morbidity by frame-based computed tomography-guided stereotactic biopsy (CTSTB with Brown-Roberts-Wells (BRW unit and by neuronavigation-guided frameless stereotactic biopsy (NSTB using magnetic resonance imaging (MRI. Methods: The subjects′ age range was 15-83 years. CTSTB with BRW unit was performed for 59 tumors (58 cases, 1988-2007. NSTB was performed for 38 tumors (35 cases, 2007-2013 with the needle sheath attached to the head holder. By NSTB, target locations of sampling points and trajectories were confirmed by using MRI. Diffusion tensor imaging-based fiber tractography was used to achieve safe trajectories. STB by using BRW did not visualize the trajectory virtually; however, the planning images for NSTB were able to show the trajectory virtually before the procedure. Results: Histological diagnoses were established for 93 tumors at the first biopsy. The diagnostic yield was 94.9% by CTSTB and 97.4% by NSTB (P = 0.944. The morbidity rate was 5.1% by CTSTB and 0% by NSTB (P = 0.417. The absolute risk reduction was 23.1% by NSTB when the targets were basal ganglia (putamen, globus pallidus or thalamus. In the cases of glioma for which the targets were basal ganglia (putamen, globus pallidus or thalamus, the absolute risk reduction by NSTB was 30%. Conclusions: There was no significant difference between CTSTB and NSTB concerning the diagnostic yield and morbidity. However, when the target is the basal ganglia (putamen, globus pallidus or thalamus and glioma is suspected, NSTB by using MRI with virtual trajectory is preferable to CTSTB concerning morbidity.

  2. Accuracy and feasibility of frameless stereotactic and robot-assisted CT-based puncture in interventional radiology. A comparative phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Stoffner, R.; Widmann, G.; Bale, R. [Radiologie, Medizinische Univ. Innsbruck (Austria); Augschoell, C. [Chirurgie, LKH Salzburg (Austria); Boehler, D. [LKH Salzburg (Austria)

    2009-09-15

    Purpose: To compare the accuracy of frameless stereotactic and robot-assisted puncture in vitro based on computed tomography (CT) imaging with a slice thickness of 1, 3, and 5 mm. Materials and Methods: 300 punctures were carried out with help of the Atlas aiming device guided by the optical navigation system Stealth Station TREONplus and 150 punctures were guided by the robotic assistance system Innomotion. Conically shaped rods were punctured with Kirschner wires. The accuracy was evaluated on the basis of control CTs by measuring the Euclidean distance between the wire tip and target and the normal distance between the target and wire. Results: With the Stealth Station a mean Euclidean distance of 1.94{+-}0.912, 2.2{+-}1.136, and 2.74{+-}1.166 mm at a slice thickness of 1, 3 and 5 mm, respectively, was reached. The mean normal distance was 1.64{+-}0.919, 1.84{+-}1.189, and 2.48{+-}1.196 mm, respectively. The Innomotion system resulted in a mean Euclidean distance of 1.69{+-}0.772, 1.91{+-}0.673, and 2.30{+-}0.881 mm, respectively, while the mean normal distance was (1.42{+-}0.78), 1.60{+-}0.733, and 1.98{+-}1.002 mm, respectively. A statistical significance between accuracies with both systems with 1 mm and 3 mm slices could not be detected (p > 0.05). At a slice thickness of 5 mm, the robot was significantly more accurate, but not as accurate as when using thinner slices (p < 0.05). The procedure time is longer for the Innomotion system ({proportional_to}30 vs. {proportional_to}18 min), and the practicability is higher with the Stealth Station. (orig.)

  3. SU-E-T-659: Quantitative Evaluation of Patient Setup Accuracy of Stereotactic Radiotherapy with the Frameless 6D-ExacTrac System Using Statistical Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, V; Jin, H; Hossain, S; Algan, O; Ahmad, S; Ali, I [University of Oklahoma Health Science Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To evaluate patient setup accuracy and quantify individual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless-6D-ExacTrac system. Methods: A statistical model was used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the BrainLAB 6D-ExacTrac system using the positioning shifts of 35 patients having cranial lesions (49 total lesions treated in 1, 3, 5 fractions). All these patients were immobilized with rigid head-and-neck masks, simulated with BrainLAB-localizer and planned with iPlan treatment planning system. Infrared imaging (IR) was used initially to setup patients. Then, stereoscopic x-ray images (XC) were acquired and registered to corresponding digitally-reconstructed-radiographs using bony-anatomy matching to calculate 6D-translational and rotational shifts. When the shifts were within tolerance (0.7mm and 1°), treatment was initiated. Otherwise corrections were applied and additional x-rays were acquired (XV) to verify that patient position was within tolerance. Results: The uncertainties from the mask, localizer, IR-frame, x-ray imaging, MV and kV isocentricity were quantified individually. Mask uncertainty (Translational: Lateral, Longitudinal, Vertical; Rotational: Pitch, Roll, Yaw) was the largest and varied with patients in the range (−1.05−1.50mm, −5.06–3.57mm, −5.51−3.49mm; −1.40−2.40°, −1.24−1.74°, and −2.43−1.90°) obtained from mean of XC shifts for each patient. Setup uncertainty in IR positioning (0.88,2.12,1.40mm, and 0.64,0.83,0.96°) was extracted from standard-deviation of XC. Systematic uncertainties of the localizer (−0.03,−0.01,0.03mm, and −0.03,0.00,−0.01°) and frame (0.18,0.25,−1.27mm,−0.32,0.18, and 0.47°) were extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the

  4. SU-E-T-132: Dosimetric Impact of Positioning Errors in Hypo-Fractionated Cranial Radiation Therapy Using Frameless Stereotactic BrainLAB System

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, V; Jin, H; Ali, I; Ahmad, S [Oklahoma Univ. Health Science Ctr., Oklahoma City, OK (United States)

    2014-06-01

    Purpose: To determine dosimetric impact of positioning errors in the stereotactic hypo-fractionated treatment of intracranial lesions using 3Dtransaltional and 3D-rotational corrections (6D) frameless BrainLAB ExacTrac X-Ray system. Methods: 20 cranial lesions, treated in 3 or 5 fractions, were selected. An infrared (IR) optical positioning system was employed for initial patient setup followed by stereoscopic kV X-ray radiographs for position verification. 6D-translational and rotational shifts were determined to correct patient position. If these shifts were above tolerance (0.7 mm translational and 1° rotational), corrections were applied and another set of X-rays was taken to verify patient position. Dosimetric impact (D95, Dmin, Dmax, and Dmean of planning target volume (PTV) compared to original plans) of positioning errors for initial IR setup (XC: Xray Correction) and post-correction (XV: X-ray Verification) was determined in a treatment planning system using a method proposed by Yue et al. (Med. Phys. 33, 21-31 (2006)) with 3D-translational errors only and 6D-translational and rotational errors. Results: Absolute mean translational errors (±standard deviation) for total 92 fractions (XC/XV) were 0.79±0.88/0.19±0.15 mm (lateral), 1.66±1.71/0.18 ±0.16 mm (longitudinal), 1.95±1.18/0.15±0.14 mm (vertical) and rotational errors were 0.61±0.47/0.17±0.15° (pitch), 0.55±0.49/0.16±0.24° (roll), and 0.68±0.73/0.16±0.15° (yaw). The average changes (loss of coverage) in D95, Dmin, Dmax, and Dmean were 4.5±7.3/0.1±0.2%, 17.8±22.5/1.1±2.5%, 0.4±1.4/0.1±0.3%, and 0.9±1.7/0.0±0.1% using 6Dshifts and 3.1±5.5/0.0±0.1%, 14.2±20.3/0.8±1.7%, 0.0±1.2/0.1±0.3%, and 0.7±1.4/0.0±0.1% using 3D-translational shifts only. The setup corrections (XC-XV) improved the PTV coverage by 4.4±7.3% (D95) and 16.7±23.5% (Dmin) using 6D adjustment. Strong correlations were observed between translation errors and deviations in dose coverage for XC. Conclusion

  5. Quantitative evaluation of patient setup uncertainty of stereotactic radiotherapy with the frameless 6D ExacTrac system using statistical modeling.

    Science.gov (United States)

    Keeling, Vance; Hossain, Sabbir; Jin, Hosang; Algan, Ozer; Ahmad, Salahuddin; Ali, Imad

    2016-05-08

    The purpose of this study is to evaluate patient setup accuracy and quantify indi-vidual and cumulative positioning uncertainties associated with different hardware and software components of the stereotactic radiotherapy (SRS/SRT) with the frameless 6D ExacTrac system. A statistical model is used to evaluate positioning uncertainties of the different components of SRS/SRT treatment with the Brainlab 6D ExacTrac system using the positioning shifts of 35 patients having cranial lesions. All these patients are immobilized with rigid head-and-neck masks, simu-lated with Brainlab localizer and planned with iPlan treatment planning system. Stereoscopic X-ray images (XC) are acquired and registered to corresponding digitally reconstructed radiographs using bony-anatomy matching to calculate 6D translational and rotational shifts. When the shifts are within tolerance (0.7 mm and 1°), treatment is initiated. Otherwise corrections are applied and additional X-rays (XV) are acquired to verify that patient position is within tolerance. The uncertain-ties from the mask, localizer, IR -frame, X-ray imaging, MV, and kV isocentricity are quantified individually. Mask uncertainty (translational: lateral, longitudinal, vertical; rotational: pitch, roll, yaw) is the largest and varies with patients in the range (-2.07-3.71 mm, -5.82-5.62 mm, -5.84-3.61 mm; -2.10-2.40°, -2.23-2.60°, and -2.7-3.00°) obtained from mean of XC shifts for each patient. Setup uncer-tainty in IR positioning (0.88, 2.12, 1.40 mm, and 0.64°, 0.83°, 0.96°) is extracted from standard deviation of XC. Systematic uncertainties of the frame (0.18, 0.25, -1.27mm, -0.32°, 0.18°, and 0.47°) and localizer (-0.03, -0.01, 0.03mm, and -0.03°, 0.00°, -0.01°) are extracted from means of all XV setups and mean of all XC distributions, respectively. Uncertainties in isocentricity of the MV radiotherapy machine are (0.27, 0.24, 0.34 mm) and kV imager (0.15, -0.4, 0.21 mm). A statisti-cal model is developed to

  6. SU-E-CAMPUS-J-05: Quantitative Investigation of Random and Systematic Uncertainties From Hardware and Software Components in the Frameless 6DBrainLAB ExacTrac System

    Energy Technology Data Exchange (ETDEWEB)

    Keeling, V; Jin, H; Hossain, S; Ahmad, S; Ali, I [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2014-06-15

    Purpose: To evaluate setup accuracy and quantify individual systematic and random errors for the various hardware and software components of the frameless 6D-BrainLAB ExacTrac system. Methods: 35 patients with cranial lesions, some with multiple isocenters (50 total lesions treated in 1, 3, 5 fractions), were investigated. All patients were simulated with a rigid head-and-neck mask and the BrainLAB localizer. CT images were transferred to the IPLAN treatment planning system where optimized plans were generated using stereotactic reference frame based on the localizer. The patients were setup initially with infrared (IR) positioning ExacTrac system. Stereoscopic X-ray images (XC: X-ray Correction) were registered to their corresponding digitally-reconstructed-radiographs, based on bony anatomy matching, to calculate 6D-translational and rotational (Lateral, Longitudinal, Vertical, Pitch, Roll, Yaw) shifts. XC combines systematic errors of the mask, localizer, image registration, frame, and IR. If shifts were below tolerance (0.7 mm translational and 1 degree rotational), treatment was initiated; otherwise corrections were applied and additional X-rays were acquired to verify patient position (XV: X-ray Verification). Statistical analysis was used to extract systematic and random errors of the different components of the 6D-ExacTrac system and evaluate the cumulative setup accuracy. Results: Mask systematic errors (translational; rotational) were the largest and varied from one patient to another in the range (−15 to 4mm; −2.5 to 2.5degree) obtained from mean of XC for each patient. Setup uncertainty in IR positioning (0.97,2.47,1.62mm;0.65,0.84,0.96degree) was extracted from standard-deviation of XC. Combined systematic errors of the frame and localizer (0.32,−0.42,−1.21mm; −0.27,0.34,0.26degree) was extracted from mean of means of XC distributions. Final patient setup uncertainty was obtained from the standard deviations of XV (0.57,0.77,0.67mm,0

  7. An optically guided microdevice comprising a nanowire

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a microdevice (100) for emitting electromagnetic radiation onto an associated object. Simultaneous non-contact spatial control over the microdevice in terms of translational movement in three dimensions, and rotational movement around at least two axes, preferably...... three axes, is possible. The microdevice further comprises a nanowire (150) being arranged for emitting electromagnetic radiation onto said associated object. This is advantageous for obtaining better spatial control of the microdevice comprising the nanowire, and this enables that light could more...

  8. Frameless ALOHA Protocol for Wireless Networks

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Popovski, Petar; Vukobratovic, Dejan

    2012-01-01

    We propose a novel distributed random access scheme for wireless networks based on slotted ALOHA, motivated by the analogies between successive interference cancellation and iterative belief-propagation decoding on erasure channels. The proposed scheme assumes that each user independently accesse...... process. Our aim is to optimize the slot access probability in order to achieve rateless-like distributions, focusing both on the maximization of the resolution probability of user transmissions and the throughput of the scheme....

  9. The evaluation of neuropsychological functions to frameless stereotactic radiofrequency amygdalohippocampectomy (SAHE) for mesial temporal lobe epilepsy (MTLE)%无框架立体定向海马杏仁核毁损术治疗颞叶内侧癫痫的神经心理学评估

    Institute of Scientific and Technical Information of China (English)

    罗惠民; 王福莉; 于雪; 赵全军; 张剑宁; 田增民; 吴朝辉; 赵虎林; 李志超; 王洪伟; 林鸿

    2012-01-01

    目的 了解无框架立体定向海马杏仁核毁损术在治疗颞叶内侧癫痫中对神经心理学功能的影响.方法 61名MRI阴性药物难治性颞叶癫痫患者在全麻下行经额旁正中入路无框架立体定向海马杏仁核复合体毁损术;其中23例成人患者分别在术前、术后一周及术后6个月进行了韦氏记忆量表及韦氏智力量表检测评分.结果 回访时间14~82个月不等,Engel Ⅰ级31例,Ⅱ级3例,Ⅲ级8例,Ⅳ级19例,痫性发作消失率(Engel Ⅰ)51%.手术前受试者的平均记忆商数、平均智力商数都明显低于健康人群中常值范围.术后一周较术前下降(P<0.05)的有语言智商、操作智商及记忆商数,总智商下降不明显(P>0.05);术后6个月以后受试者较术前明显增加(P<0.05)的有总智商、语言智商、操作智商及记忆商数.右颞叶内侧毁损者言语智商较术前明显增加(P<0.05).结论 无框架立体定向海马杏仁核毁损术术后早期存在记忆力及智力下降,但此类认知功能的下降程度较轻,且会在术后6个月内恢复甚至较术前明显改善,远期来讲右侧手术者其语言智商改善更为明显.无框架立体定向海马杏仁核毁损术在神经心理学功能保留方面是可逆的、甚至是有益的.%Objective To evaluate the risk of a decline of neuropsychological functions for frameless stereotactic radiofrequency amygdalohippocampectomy (SAHE) to mesial temporal lobe epilepsy (MTLE). Methods 61 patients with MTLE were experienced SAHE. Among them, 23 adult patients were compared neuropsychological results before, 7days and 6 monthts after surgery with WAIS-RC and WMS-RC. Results After 14 - 82 months follow-up, 31 patients were classified as Engel ClassⅠ, 3 patients were assessed as Engel Ⅱ, 8 patients were assessed as Engel Ⅲand 19 patients as Engel Ⅳ. The mean scores of neuropsychological examinations including IQ and MQ in patients with medial temporal lobe

  10. Clinical results of LINAC-based stereotactic radiosurgery for pituitary adenoma

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Julia; Yoshida, Masanori; Shioura, Hiroki; Kawamura, Yasutaka; Ito, Harumi; Takeuchi, Hiroaki; Kubota, Toshihiko [Fukui Medical Univ., Matsuoka (Japan); Maruyama, Ichiro [The Wakasa Wan Energy Research Center, Tsuruga, Fukui (Japan)

    2003-05-01

    We retrospectively evaluated our clinical results of stereotactic radiosurgery (SRS) for pituitary adenoma. Between 1995 and 2000, 13 patients were treated with SRS for pituitary adenoma. In all cases, the tumors had already been surgically resected. The adenomas were functional in 5 and non-functional in 8 patients. The median follow-up period was 30 months. SRS was performed with the use of a dedicated stereotactic 10-MV linear accelerator (LINAC). The median dose to the tumor margin was 15 Gy. The dose to the optic apparatus was limited to less than 8 Gy. MR images of 12 patients revealed tumor complete response (CR) in one case and partial response (PR) in 9 cases; in the remaining two patients, tumor size decreased by less than 50%. There was no recognizable regrowth of any of the tumors. In two of four GH-secreting adenomas, hormonal overproduction normalized, while the other two showed reduced hormonal production. One PRL-secreting adenoma did not respond. Reduction of visual acuity and field was seen in one patient. This patient also had a brain infarction. None of the patients developed brain radionecrosis or radiation-induced hypopituitarism. Although further studies based on greater numbers of cases and longer follow-up periods are needed, our results suggest that SRS seems to be a safe, effective treatment for pituitary adenoma. (author)

  11. High Repetition Rate, LINAC-based Nuclear Resonance Fluorescence FY 2009 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mathew Kinlaw; Scott Watson; James Johnson; Alan Hunt; Heather Seipel; Edward Reedy

    2009-10-01

    Nuclear Resonance Fluorescence (NRF), which is possible for nuclei with atomic numbers greater than helium (Z=2), occurs when a nuclear level is excited by resonant absorption of a photon and subsequently decays by reemission of a photon. The excited nuclear states can become readily populated, provided the incident photon’s energy is within the Doppler-broadened width of the energy level being excited. Utilizing continuous energy photon spectra, as is characteristic of a bremsstrahlung photon beam, as the inspection source, ensures that at least some fraction of the impinging beam will contribute to the population of the excited energy levels in the material of interest. Upon de-excitation, either to the ground state or to a lower-energy excited state, the emitted fluorescence photon’s energy will correspond to the energy difference between the excited state and the state to which it decays. As each isotope inherently contains unique nuclear energy levels, the NRF states for each isotope are also unique. By exploiting this phenomenon, NRF photon detection provides a well-defined signature for identifying the presence of individual nuclear species. This report summarizes the second year (Fiscal Year [FY] 2009) of a collaborative research effort between Idaho National Laboratory, Idaho State University’s Idaho Accelerator Center, and Pacific Northwest National Laboratory. This effort focused on continuing to assess and optimize NRF-based detection techniques utilizing a slightly modified, commercially available, pulsed medical electron accelerator.

  12. Linac-based total body irradiation (TBI) with volumetric modulated arc therapy (VMAT)

    Science.gov (United States)

    Tas, B.; Durmus, I. F.; Okumus, A.; Uzel, O. E.

    2017-02-01

    To evaluate dose distribution of Volumetric modulated arc therapy (VMAT) planning tecnique using Versa HD® lineer accelerator to deliver Total Body Irradiation (TBI) on the coach. Eight TBI patient's Treatment Planning System (TPS) were performed with dual arc VMAT for each patient. The VMAT-TBI consisted of three isocentres and three dual overlapping arcs. The prescribed dose was 12 Gy. Mean dose to lung and kidney were restricted less than 10 Gy and max. dose to lens were restricted less than 6 Gy. The plans were verified using 2D array and ion chamber. The comparison between calculation and measurement were made by γ-index analysis and absolute dose. An average total delivery time was determined 923±34 seconds and an average MU was determined 2614±228 MUs for dual arc VMAT. Mean dose to lungs was 9.7±0.2 Gy, mean dose to kidneys was 8.8±0.3 Gy, max. dose to lens was 5.5±0.3 Gy and max. dose was 14.6±0.3 Gy, HI of PTV was 1.13±0.2, mean dose to PTV was 12.6±1.5 Gy and mean γ-index pass rate was %97.1±1.9. The results show that the tecnique for TBI using VMAT on the treatment coach is feasible.

  13. S-band linac-based X-ray source with {pi}/2-mode electron linac

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, Abhay, E-mail: abhay@post.kek.jp [Department of Accelerator Science, School of High Energy Accelerator Science, Graduate University for Advanced Studies, Shonan International Village, Hayama, Miura, Kanagawa 240-0193 (Japan); Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Araki, Sakae [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Dixit, Tanuja [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Fukuda, Masafumi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Krishnan, R; Pethe, Sanjay [Society for Applied Microwave Electronic Engineering and Research (SAMEER), R and D Laboratory of the Government of India, IIT Campus, Powai, Mumbai 400 076 (India); Sakaue, Kazuyuki [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Terunuma, Nobuhiro; Urakawa, Junji [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Washio, Masakazu [Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan)

    2011-05-01

    The activities with the compact X-ray source are attracting more attention, particularly for the applications of the source in medical fields. We propose the fabrication of a compact X-ray source using the SAMEER electron linear accelerator and the KEK laser undulator X-ray source (LUCX) technologies. The linac developed at SAMEER is a standing wave side-coupled S-band linac operating in the {pi}/2 mode. In the proposed system, a photocathode RF gun will inject bunches of electrons in the linac to accelerate and achieve a high-energy, low-emittance beam. This beam will then interact with the laser in the laser cavity to produce X-rays of a type well suited for various applications. The side-coupled structure will make the system more compact, and the {pi}/2 mode of operation will enable a high repetition rate operation, which will help to increase the X-ray yield.

  14. LUX — A Recirculating Linac-based Ultrafast X-ray Source

    Science.gov (United States)

    Corlett, J. N.; Barletta, W. A.; DeSantis, S.; Doolittle, L.; Fawley, W. M.; Green, M. A.; Heimann, P.; Leone, S. R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2004-05-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme. We describe the facility major systems and peformance.

  15. A recirculating linac based synchrotron light source for ultrafast x-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barry, W.; Byrd, J.M.; DeSantis, S.; Heimann, P.; Lidia, S.; Li, D.; Rimmer, R.; Robinson, K.; Schoenlein, R.; Tanabe, J.; Wang, S.; Wan, W.; Wells, R.; Zholents, A.; Placidi, M.; Pirkl, W.

    2002-05-30

    LBNL is pursuing a multi-divisional initiative that has this year further developed design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration. Our proposed x-ray facility [1] has the short x-ray pulse length ({approx};60 fs FWHM) necessary to study very fast dynamics, high flux (approximately 1011 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-10 keV photon energy. The photon production section of the machine accomodates seven 2m long undulators and six 2T field dipole magnets. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typicaly have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimise high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression.

  16. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barry, W.; Barletta, W.A.; Byrd, J.M.; DeSantis, S.; Doolittle, L.; Fawley, W.; Green, M.A.; Hartman, N.; Heimann, P.; Kairan, D.; Kujawski, E.; Li, D.; Lidia, S.; Luft, P.; McClure, R.; Parmigiani, F.; Petroff, Y.; Pirkl, W.; Placidi, M.; Reavill, D.; Reichel, I.; Rimmer, R.A.; Ratti, A.; Robinson, K.E.; Sannibale, F.; Schoenlein, R.; Staples, J.; Tanabe, J.; Truchlikova, D.; Wan, W.; Wang, S.; Wells, R.; Wolski, A.; Zholents, A.

    2002-12-21

    LBNL is pursuing design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length ({approx}60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimize high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression. Synchronization of x-ray pulses to sample excitation signals is expected to be of order 50 - 100 fs. Techniques for making use of the recirculating geometry to provide beam-based signals from early passes through the machine are being studied.

  17. LUX - a recirculating linac-based facility for ultrafast X-ray science

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Penn, G.; Ratti, A.; Reinsch, M.; Schoenlein, R.; Staples, J.; Stover, G.; Virostek, S.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Wurtele, J.; Zholents, A.

    2004-06-29

    We present recent developments in design concepts for LUX - a source of ultra-short synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science [1]. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1-10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, independently tunable harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and resistive wall wakefields. Timing jitter between pump lasers and x-ray pulses is minimized by use of a stable optical master oscillator, distributing timing signals over actively stabilized fiber-optic, phase-locking all lasers to the master oscillator, and generating all rf signals from the master oscillator. We describe technical developments including techniques for minimizing power dissipation in a high repetition rate rf photocathode gun, beam dynamics in two injector configurations, independently tunable beamlines for VUV and soft x-ray production by cascaded harmonic generation, a fast kicker design, timing systems for providing synchronization between experimental pump lasers and the x-ray pulse, and beamline design for maintaining nm-scale density modulation.

  18. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    CERN Document Server

    Corlett, J N; Barry, W; Byrd, J M; De Santis, S; Doolittle, L; Fawley, W; Green, M A; Hartman, N; Heimann, P A; Kairan, D; Kujawski, E; Li, D; Lidia, S M; Luft, P; McClure, R; Parmigiani, F; Petroff, Y; Pirkl, Werner; Placidi, Massimo; Ratti, A; Reavill, D; Reichel, I; Rimmer, R A; Robinson, K E; Sannibale, F; Schönlein, R W; Staples, J; Tanabe, J; Truchlikova, D; Wan, W; Wang, S; Wells, R; Wolski, A; Zholents, A

    2002-01-01

    LBNL is pursuing design studies and the scientific program for a facility of the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length (approx 60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses use...

  19. LUX - A recirculating linac-based ultrafast X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Green, M.A.; Heimann, P.; Leone, S.R.; Lidia, S.; Li, D.; Parmigiani, F.; Ratti, A.; Robinson, K.; Schoenlein, R.; Staples, J.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Zholents, A.

    2003-08-01

    We describe the design of a proposed source of ultra-fast synchrotron radiation x-ray pulses based on a recirculating superconducting linac, with an integrated array of ultrafast laser systems. The source produces x-ray pulses with duration of 10-50 fs at a 10 kHz repetition rate, with tunability from EUV to hard x-ray regimes, and optimized for the study of ultra-fast dynamics. A high-brightness rf photocathode provides electron bunches. An injector linac accelerates the beam to the 100 MeV range, and is followed by four passes through a 700 MeV recirculating linac. Ultrafast hard x-ray pulses are obtained by a combination of electron bunch manipulation, transverse temporal correlation of the electrons, and x-ray pulse compression. EUV and soft x-ray pulses as short as 10 fs are generated in a harmonic-cascade free electron laser scheme.

  20. Gamma Knife and LINAC-Based Stereotactic Treatments of Intracranial Targets: Dosimetric and Radiobiological Considerations

    Science.gov (United States)

    Kendall, Ethan Lee

    The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap water rather than distilled water as the test sample. Flyer plate experiments were conducted in the Shock Physics Laboratory at Marquette University to determine the structure of shock waves within water. A 12.7 mm bore gas gun fired a projectile made of copper, PMMA, or aluminum at a stationary target filled with tap water. Graphite break pins in a circuit determined the initial projectile velocity prior to coming into contact with the target. A Piezoelectric timing pin (PZT pin) at the front surface of the water sample determined the arrival of the leading wave and a Photon Doppler Velocimeter (PDV) measured particle velocity from the rear surface of the water sample. The experimental results were compared to simulated data from a Eulerian Hydrocode called CTH [1]. The experimental results differed from the simulated results with deviations believed to be from experimental equipment malfunctions. The main hypothesis being that the PZT pin false triggered, resulting in measured lower than expected shock velocities. The simulated results were compared to published data from various authors and was within range.

  1. The Interaction of Optical Guided Modes with Waveguide Diffraction Gratings.

    Science.gov (United States)

    Weller-Brophy, Laura Ann

    In this thesis the results of a theoretical and experimental investigation of the coupling of guided modes by waveguide gratings are presented. This work is motivated by the potential application of waveguide gratings to integrated optical devices. The coupling of guided modes obliquely incident to both periodic and aperiodic gratings is a mechanism basic to the operation of integrated optical components such as filters, reflectors, beamsplitters, and modulators. It is shown in the Introduction to this thesis, that this mechanism is not modeled consistently by the analyses presented in the literature. For the case of TM-TM coupling, virtually each analytical treatment predicts a different value for the grating reflectivity. In addition, it is found that the typical Coupled-Mode formalisms used to derive the grating reflectivity do not offer an intuitive picture of the operation of waveguide gratings. These two particular problem areas serve as the focal points of this thesis. The latter of these is addressed through the development of a thin film model of the operation of waveguide gratings. This model presents an intuitively appealing picture of the interaction of waveguide gratings and guided modes. It also yields grating reflectivities which are in excellent agreement with those obtained through the numerical solution of the Coupled-Mode equations for both periodic and aperiodic gratings. The bulk of this research project is directed towards resolving the conflicting theoretical grating analyses presented in the literature. A new derivation of the coupling of guided modes obliquely incident to periodic gratings is presented in Chapter II of this thesis. This derivation is based on the Local Normal Mode expansion used by Marcuse for the case of normal incidence. It produces coupling coefficients which are nearly identical to those derived using the rigorous Boundary Perturbation technique. The coupling coefficients predicted by this Local Normal Mode formalism are shown to differ substantially from those obtained using the Ideal Mode expansion. In Chapter V the details of an experiment designed to determine the accuracy of each of these Coupled-Mode theories is described. While the Ideal Mode theory is typically quoted in the literature, it produces results for the TM-TM coupling which are not substantiated by experimental measurements. The measured grating reflectivities are shown to have features more accurately modeled by the Local Normal Mode formalism presented in Chapter II.

  2. Laser Plasmas : Optical guiding of laser beam in nonuniform plasma

    Indian Academy of Sciences (India)

    Tarsem Singh Gill

    2000-11-01

    A plasma channel produced by a short ionising laser pulse is axially nonuniform resulting from the self-defocusing. Through such preformed plasma channel, when a delayed pulse propagates, the phenomena of diffraction, refraction and self-phase modulation come into play. We have solved the nonlinear parabolic partial differential equation governing the propagation characteristics for an approximate analytical solution using variational approach. Results are compared with the theoretical model of Liu and Tripathi (Phys. Plasmas 1, 3100 (1994)) based on paraxial ray approximation. Particular emphasis is on both beam width and longitudinal phase delay which are crucial to many applications.

  3. Population based ranking of frameless CT-MRI registration methods

    Energy Technology Data Exchange (ETDEWEB)

    Opposits, Gabor; Kis, Sandor A.; Tron, Lajos; Emri, Miklos [Debrecen Univ. (Hungary). Dept. of Nuclear Medicine; Berenyi, Ervin [Debrecen Univ. (Hungary). Dept. of Biomedical Laboratory and Imaging Science; Takacs, Endre [Rotating Gamma Ltd., Debrecen (Hungary); Dobai, Jozsef G.; Bognar, Laszlo [Debrecen Univ., Medical Center (Hungary). Dept. of Neurosurgery; Szuecs, Bernadett [ScanoMed Ltd., Debrecen (Hungary)

    2015-07-01

    Clinical practice often requires simultaneous information obtained by two different imaging modalities. Registration algorithms are commonly used for this purpose. Automated procedures are very helpful in cases when the same kind of registration has to be performed on images of a high number of subjects. Radiotherapists would prefer to use the best automated method to assist therapy planning, however there are not accepted procedures for ranking the different registration algorithms. We were interested in developing a method to measure the population level performance of CT-MRI registration algorithms by a parameter of values in the [0,1] interval. Pairs of CT and MRI images were collected from 1051 subjects. Results of an automated registration were corrected manually until a radiologist and a neurosurgeon expert both accepted the result as good. This way 1051 registered MRI images were produced by the same pair of experts to be used as gold standards for the evaluation of the performance of other registration algorithms. Pearson correlation coefficient, mutual information, normalized mutual information, Kullback-Leibler divergence, L{sub 1} norm and square L{sub 2} norm (dis)similarity measures were tested for sensitivity to indicate the extent of (dis)similarity of a pair of individual mismatched images. The square Hellinger distance proved suitable to grade the performance of registration algorithms at population level providing the developers with a valuable tool to rank algorithms. The developed procedure provides an objective method to find the registration algorithm performing the best on the population level out of newly constructed or available preselected ones.

  4. SU-E-J-48: Imaging Origin-Radiation Isocenter Coincidence for Linac-Based SRS with Novalis Tx

    Energy Technology Data Exchange (ETDEWEB)

    Geraghty, C; Workie, D; Hasson, B [Anne Arundel Medical Center, Annapolis, MD (United States)

    2015-06-15

    Purpose To implement and evaluate an image-based Winston-Lutz (WL) test to measure the displacement between ExacTrac imaging origin and radiation isocenter on a Novalis Tx system using RIT V6.2 software analysis tools. Displacement between imaging and radiation isocenters was tracked over time. The method was applied for cone-based and MLC-based WL tests. Methods The Brainlab Winston-Lutz phantom was aligned to room lasers. The ExacTrac imaging system was then used to detect the Winston- Lutz phantom and obtain the displacement between the center of the phantom and the imaging origin. EPID images of the phantom were obtained at various gantry and couch angles and analyzed with RIT calculating the phantom center to radiation isocenter displacement. The RIT and Exactrac displacements were combined to calculate the displacement between imaging origin and radiation isocenter. Results were tracked over time. Results Mean displacements between ExacTrac origin and radiation isocenter were: VRT: −0.1mm ± 0.3mm, LNG: 0.5mm ± 0.2mm, LAT: 0.2mm ± 0.2mm (vector magnitude of 0.7 ± 0.2mm). Radiation isocenter was characterized by the mean of the standard deviations of the WL phantom displacements: σVRT: 0.2mm, σLNG: 0.4mm, σLAT: 0.6mm. The linac couch base was serviced to reduce couch walkout. This reduced σLAT to 0.2mm. These measurements established a new baseline of radiation isocenter-imaging origin coincidence. Conclusion The image-based WL test has ensured submillimeter localization accuracy using the ExacTrac imaging system. Standard deviations of ExacTrac-radiation isocenter displacements indicate that average agreement within 0.3mm is possible in each axis. This WL test is a departure from the tradiational WL in that imaging origin/radiation isocenter agreement is the end goal not lasers/radiation isocenter.

  5. Estimation of Secondary Skin Cancer Risk Due To Electron Contamination in 18-MV LINAC-Based Prostate Radiotherapy

    Directory of Open Access Journals (Sweden)

    Seyed Mostafa Ghavami

    2016-12-01

    Full Text Available Introduction Accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction Materials and Methods Electron contamination in prostate radiotherapy was investigated using the Monte Carlo (MC code calculation. In addition, field size dependence of the skin dose was assessed. Excess cancer risk induced by electron contamination was determined for the skin, surface dose, and prostate dose-volume histogram (DVH using MC calculation and analytical methods. Results MC calculations indicated that up to 80% of total electron contamination fluence was produced in the linear accelerator. At 5 mm below the skin surface, surface dose was estimated at 6%, 13%, 27%, and 38% for 5×5 cm2, 10×10 cm2, 20×20 cm2, and 40×40 cm2 field sizes, respectively. Relative dose at Dmax was calculated at 0.92% and 5.42% of the maximum dose for 5×5 cm2 and 40×40 cm2 field sizes, respectively. Excess absolute skin cancer risk was obtained at 2.96×10-4 (PY -1 for total 72 Gy. Differences in prostate and skin DVHs were 1.01% and 1.38%, respectively. Conclusion According to the results of this study, non-negligible doses are absorbed from contaminant electrons by the skin, which is associated with an excess risk of cancer induction.

  6. SU-E-T-54: A New Method for Optimizing Radiation Isocenter for Linac-Based SRS

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, S [Southeast Missouri Hospital, Cape Girardeau, MO (United States); Hyer, D; Nixon, E [University Of Iowa, Iowa City, IA (United States)

    2015-06-15

    Purpose: To develop a new method to minimize deviation of linac x-ray beams from the centroid of the volumetric radiation isocenter for all combinations of gantry and table angle. Methods: A set of ball-bearing (Winston-Lutz) images was used to determine the gantry radiation isocenter as the midrange of deviation values. Deviations in the cross-plane direction were minimized by calibration of MLC leaf position offset, and by adjusting beam position steering for each energy. Special attention was also paid to matching the absolute position of isocenter across all energies by adjusting position steering in the gun-target axis. Displacement of table axis from the gantry isocenter, and recommended table axis adjustment for contemporary Elekta linacs, was also determined. Eight images were used to characterize the volumetric isocenter for the full range of gantry and table rotations available. Tabulation of deviation for each beam was used to test compliance with isocenter tolerance. Results: Four contemporary Elekta linacs were evaluated and the radius in the gun-target axis of the radiation isocenter was 0.5 to 0.7 mm. After beam steering adjustment, the radius in the cross-plane direction was typically 0.2 to 0.4 mm. Position matching between energies can be reduced to 0.28 mm. Maximum total deviation was 0.68 to 1.07 mm, depending primarily on the effect of systematic table axis wobble with rotation. Conclusion: This new method effectively facilitates minimization of deviation between beam center and target position. The test, which requires a few minutes to perform, can be easily incorporated into a routine machine QA program. A tighter radiation isocenter for contemporary Elekta linacs would require reducing the effect of gantry arm flex and/or table axis wobble that are the two main components of deviation from the designated isocenter point.

  7. A Compact 5 MeV S-Band Electron Linac Based X-Ray Source for Industrial Radiography

    CERN Document Server

    Auditore, Lucrezia; De Pasquale, Domenico; Emanuele, Umberto; Italiano, Antonio; Trifirò, Antonio; Trimarchi, Marina

    2005-01-01

    A compact and reliable X-ray source, based on a 5 MeV, 1 kW, S-band electron linac, has been set up at the Dipartimento di Fisica, Universit\\'a di Messina. This source, coupled with a GOS scintillator screen and a CCD camera, represents an innovative transportable system for industrial radiography and X-ray tomography. Optimization of the parameters influencing the e-gamma conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 code. The converter choice is the result of the study of the e-gamma conversion performances for different materials and materials thicknesses. Also the converter position with respect to the linac exit window was studied. The chosen converter consists in a Ta-Cu target inserted close to the linac window. The Cu layer acts as a filter both on the electrons from the source and on the low energy X-rays. The X-ray beam angular profile was studied by means of GafChromic films with and without collimation. In the final source project, a collimation system pr...

  8. Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

    Science.gov (United States)

    Muranaka, T.; Debu, P.; Dupré, P.; Liszkay, L.; Mansoulie, B.; Pérez, P.; Rey, J. M.; Ruiz, N.; Sacquin, Y.; Crivelli, P.; Gendotti, U.; Rubbia, A.

    2010-04-01

    We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5·1011 per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

  9. WE-B-19A-01: SRT II: Uncertainties in SRT

    Energy Technology Data Exchange (ETDEWEB)

    Dieterich, S [UC Davis Medical Center, Sacramento, CA (United States); Schlesinger, D [University of Virginia Health Systems, Charlottesville, VA (United States); Geneser, S [University of California San Francisco, San Francisco, CA (United States)

    2014-06-15

    SRS delivery has undergone major technical changes in the last decade, transitioning from predominantly frame-based treatment delivery to imageguided, frameless SRS. It is important for medical physicists working in SRS to understand the magnitude and sources of uncertainty involved in delivering SRS treatments for a multitude of technologies (Gamma Knife, CyberKnife, linac-based SRS and protons). Sources of SRS planning and delivery uncertainty include dose calculation, dose fusion, and intra- and inter-fraction motion. Dose calculations for small fields are particularly difficult because of the lack of electronic equilibrium and greater effect of inhomogeneities within and near the PTV. Going frameless introduces greater setup uncertainties that allows for potentially increased intra- and interfraction motion, The increased use of multiple imaging modalities to determine the tumor volume, necessitates (deformable) image and contour fusion, and the resulting uncertainties introduced in the image registration process further contribute to overall treatment planning uncertainties. Each of these uncertainties must be quantified and their impact on treatment delivery accuracy understood. If necessary, the uncertainties may then be accounted for during treatment planning either through techniques to make the uncertainty explicit, or by the appropriate addition of PTV margins. Further complicating matters, the statistics of 1-5 fraction SRS treatments differ from traditional margin recipes relying on Poisson statistics. In this session, we will discuss uncertainties introduced during each step of the SRS treatment planning and delivery process and present margin recipes to appropriately account for such uncertainties. Learning Objectives: To understand the major contributors to the total delivery uncertainty in SRS for Gamma Knife, CyberKnife, and linac-based SRS. Learn the various uncertainties introduced by image fusion, deformable image registration, and contouring

  10. CyberKnife radiosurgery: Precision without incision

    Directory of Open Access Journals (Sweden)

    Enja Siva Prasad Reddy

    2015-01-01

    Full Text Available CyberKnife stereotactic radiosurgery system is an innovative, effective, frameless, non-invasive substitute for conventional surgical treatment of cancer. It works on the principle of stereotaxy. It is used for the treatment of both cancerous and non-cancerous tumors, intracranial lesions, tumors of lung, spine, prostate, and kidney, recurrent cases of oral squamous cell carcinoma, arteriovenous malformation, and trigeminal neuralgia. It has an advantage over other systems like Gamma knife radiosurgery and linear accelerator (LINAC-based systems, as it is frameless, has submillimeter accuracy, does not affect the normal cells adjacent to the lesion, and tracks the lesion in synchronization with the patient′s respiratory rate. The future of CyberKnife encompasses possibilities such as incremental improvements in accuracy and better shaping of the field of radiation and would certainly allow extension of radiosurgery as an effective substitute for chemotherapy. This paper aims to review and highlight the immense potential that CyberKnife holds in the field of dentistry in treating disorders of the head and neck region, thereby ensuring enhanced longevity for the patients.

  11. Improving Surgical Resection of Metastatic Liver Tumors With Near-Infrared Optical-Guided Fluorescence Imaging.

    Science.gov (United States)

    Barabino, Gabriele; Porcheron, Jack; Cottier, Michèle; Cuilleron, Muriel; Coutard, Jean-Guillaume; Berger, Michel; Molliex, Serge; Beauchesne, Brigitte; Phelip, Jean Marc; Grichine, Alexei; Coll, Jean-Luc

    2016-08-01

    Objective The aim of this study was to investigate the feasibility and future clinical applications of near-infrared (NIR) fluorescence imaging to guide liver resection surgery for metastatic cancer to improve resection margins. Summary Background Data A subset of patients with metastatic hepatic tumors can be cured by surgery. The degree of long-term and disease-free survival is related to the quality of surgery, with the best resection defined as "R0" (complete removal of all tumor cells, as evidenced by microscopic examination of the margins). Although intraoperative ultrasonography can evaluate the surgical margins, surgeons need a new tool to perfect the surgical outcome. Methods A preliminary study was performed on 3 patients. We used NIR imaging postoperatively "ex vivo" on the resected liver tissue. The liver tumors were preoperatively labelled by intravenously injecting the patient with indocyanine green (ICG), a NIR fluorescent agent (24 hours before surgery, 0.25 mg/kg). Fluorescent images were obtained using a miniaturized fluorescence imaging system (FluoStic, Fluoptics, Grenoble, France). Results After liver resection, the surgical specimens from each patient were sliced into 10-mm sections in the operating room and analyzed with the FluoStic. All metastatic tumors presented rim-type fluorescence. Two specimens had incomplete rim fluorescence. The pathologist confirmed the presence of R1 margins (microscopic residual resection), even though the ultrasonographic analysis indicated that the result was R0. Conclusions Surgical liver resection guided by NIR fluorescence can help detect potentially uncertain anatomical areas that may be missed by preoperative imaging and by ultrasonography during surgery. These preliminary results will need to be confirmed in a larger prospective patient series.

  12. A frameless, cylindrically shaped, multiwire proportional chamber using charge division readout

    CERN Document Server

    Fainberg, A; Linscott, I; Moneti, G

    1977-01-01

    PWCs have been constructed in the shape of cylindrical quandrants, placed them around the bicone in an experiment at the CERN ISR, and operated them in a charge division mode to obtain two dimensional position information. A pair of PWCs share a cylindrical styrofoam shell as the basic support member, and contain approximately 0.008 radiation lengths of material. The observed charge division resolution is delta x/L approximately 0.5% in reasonable agreement with an expected resolution of approximately 0.3% due primarily to digitization noise. Reduction of digitization noise is limited by available dynamic range of the electronics and the width of the pulse height distributions. A method is described, using X-rays from /sup 55 /Fe strip sources for calibrating the electronics, which is sufficiently accurate to match the observed resolution. (13 refs).

  13. Frameless high dose rate stereotactic lung radiotherapy: intrafraction tumor position and delivery time.

    Science.gov (United States)

    Peguret, Nicolas; Dahele, Max; Cuijpers, Johan P; Slotman, Ben J; Verbakel, Wilko F A R

    2013-06-01

    Intrafraction change in tumor position (Δ) was evaluated for stereotactic lung radiotherapy delivered with flattening filter free volumetric modulated arc therapy. In 140 fractions from 32 patients mean Δ (±SD) was -0.7±1.4 mm (vertical), -0.7±1.3 mm (longitudinal) and +0.2±1.2 mm (lateral) with mean vector 2.1±1.2 mm. Mean delivery time was 4.4±3.4 min (mean beam-on 1.9±0.4 min). Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. SU-E-T-420: Failure Effects Mode Analysis for Trigeminal Neuralgia Frameless Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Howe, J [Associates In Medical Physics, Louisville, KY (United States)

    2015-06-15

    Purpose: Functional radiosurgery has been used successfully in the treatment of trigeminal neuralgia but presents significant challenges to ensuring the high prescription dose is delivered accurately. A review of existing practice should help direct the focus of quality improvement for this treatment regime. Method: Failure modes and effects analysis was used to identify the processes in preparing radiosurgery treatment for TN. The map was developed by a multidisciplinary team including: neurosurgeon, radiation oncology, physicist and therapist. Potential failure modes were identified for each step in the process map as well as potential causes and end effect. A risk priority number was assigned to each cause. Results: The process map identified 66 individual steps (see attached supporting document). Corrective actions were developed for areas of high risk priority number. Wrong site treatment is at higher risk for trigeminal neuralgia treatment due to the lack of site specific pathologic imaging on MR and CT – additional site specific checks were implemented to minimize the risk of wrong site treatment. Failed collision checks resulted from an insufficient collision model in the treatment planning system and a plan template was developed to address this problem. Conclusion: Failure modes and effects analysis is an effective tool for developing quality improvement in high risk radiotherapy procedures such as functional radiosurgery.

  15. Neuroendoscopic Intraventricular Biopsy in Children with Small Ventricles Using Frameless VarioGuide System.

    Science.gov (United States)

    Avecillas-Chasin, Josué M; Budke, Marcelo; Villarejo, Francisco

    2016-03-01

    Endoscopic biopsy for intraventricular tumors in pediatric patients with small ventricles is a challenging procedure because of the risk of morbidity during the intraventricular approach. We describe the use of the VarioGuide system for intraventricular endoscopic biopsy in 9 consecutive pediatric patients with intraventricular lesions and small ventricular size. All patients had lesions in the anterior part of the third ventricle with a median frontal and occipital horn ratio of 0.33. Patients presented with growth failure (n = 4), visual disturbances (n = 4), and seizures (n = 1). The VarioGuide system consists of an ergonomic arm with 3 joints for gross adjustment. The 3 rotational joints on the distal side of the system are adjusted according to the angles of the planned trajectory. The endoscope is adjusted to the distal side of the VarioGuide and inserted through the ring, previously set for the diameter of the endoscope and for the planned trajectory. The accuracy of the trajectory and correct ventricular cannulation are confirmed under endoscopic guidance. The biopsy is carried out according to the standard technique. In all cases, the biopsy sample provided the definitive diagnosis. Diagnoses included germinomas in 4 patients, hamartoma in 1 patient, hypothalamic astrocytoma in 2 patients, and craniopharyngioma in 2 patients. The use of the VarioGuide system for intraventricular endoscopic biopsy is highly recommended for pediatric patients with small ventricle size. This technique may help minimize the risk of unnecessary brain damage during the entrance to small ventricles.

  16. Establishing an Initial Electron Beam Model with Monte Carlo Simulation for a Single 6 MV X-ray Medical Linac Based on Particle Dynamics Characteristics

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong-bin; KONG Xiao-xiao; LI Quan-feng; LIN Xiao-qi; BAO Shang-lian

    2009-01-01

    Objective:In this study,we try to establish an initial electron beam model by combining Monte Carlo simulation method with particle dynamic calculation (TRSV) for the single 6 MV X-ray accelerating waveguide of BJ- 6 medical linac. Methods and Materials:1. We adapted the treatment head configuration of BJ- 6 medical linac made by Beijing Medical Equipment Institute (BMEI) as the radiation system for this study. 2. Use particle dynamics calculation code called TRSV to drive out the initial electron beam parameters of the energy spectrum, the spatial intensity distribution, and the beam incidence angle. 3. Analyze the 6 MV X-ray beam characteristics of PDDc, OARc in a water phantom by using Monte Carlo simulation (BEAMnrc,DOSXYZnrc) for a preset of the initial electron beam parameters which have been determined by TRSV, do the comparisons of the measured results of PDDm, OARm in a real water phantom, and then use the deviations of calculated and measured results to slightly modify the initial electron beam model back and forth until the deviations meet the error less than 2%. Results:The deviations between the Monte Carlo simulation results of percentage depth doses at PDDc and off-axis ratios OARc and the measured results of PDDm and OARm in a water phantom were within 2%. Conclusion:When doing the Monte Carlo simulation to determine the parameters of an initial electron beam for a particular medical linac like BJ- 6, modifying some parameters based on the particle dynamics calculation code would give some more reasonable and more acceptable results.

  17. Radiation-Induced Peripheral Malignant Nerve Sheath Tumor Arising from Vestibular Schwannoma after Linac-Based Stereotactic Radiation Therapy: A Case Report and Review of Literatures

    Directory of Open Access Journals (Sweden)

    Putipun Puataweepong

    2012-01-01

    Full Text Available In recent years the use of stereotactic radiation for vestibular schwannomas has increased worldwide. However, malignant transformation associated with radiation, although uncommon, has been reported in recent publications. We present a case of the 34 year-old female who had left vestibular schwannoma and who underwent surgery and postoperative stereotactic radiotherapy (SRT, hypofraction in 2005. At 6 years after SRT, the patient came with left facial palsy and severe headache. CT brain revealed progression in size with cystic and hemorrhagic changes of the preexisting tumor at left CPA with new obstructive hydrocephalus. Partial tumor removal was done, and the pathological report was malignant peripheral nerve sheath tumor (MPNST. Regarding the uncertainty of carcinogenesis risk, we should still practice radiation therapy with caution, especially in the young patient with tumor predisposition syndrome. Because of low incidence of MPNST after radiation, it should not be a major decision about giving radiotherapy. However, with the poor prognosis of MPNST, this possibility should be explained to the patient before radiation treatment option.

  18. Linac-based extracranial radiosurgery with Elekta volumetric modulated arc therapy and an anatomy-based treatment planning system: Feasibility and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Cilla, Savino, E-mail: savinocilla@gmail.com [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Deodato, Francesco; Macchia, Gabriella; Digesù, Cinzia [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Ianiro, Anna; Viola, Pietro; Craus, Maurizio [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Valentini, Vincenzo [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Radiation Oncology Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Piermattei, Angelo [Medical Physics Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Morganti, Alessio G. [Radiation Oncology Unit, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, S. Orsola-Malpighi Hospital, University of Bologna, Bologna (Italy)

    2016-07-01

    We reported our initial experience in using Elekta volumetric modulated arc therapy (VMAT) and an anatomy-based treatment planning system (TPS) for single high-dose radiosurgery (SRS-VMAT) of liver metastases. This study included a cohort of 12 patients treated with a 26-Gy single fraction. Single-arc VMAT plans were generated with Ergo++ TPS. The prescription isodose surface (IDS) was selected to fulfill the 2 following criteria: 95% of planning target volume (PTV) reached 100% of the prescription dose and 99% of PTV reached a minimum of 90% of prescription dose. A 1-mm multileaf collimator (MLC) block margin was added around the PTV. For a comparison of dose distributions with literature data, several conformity indexes (conformity index [CI], conformation number [CN], and gradient index [GI]) were calculated. Treatment efficiency and pretreatment dosimetric verification were assessed. Early clinical data were also reported. Our results reported that target and organ-at-risk objectives were met for all patients. Mean and maximum doses to PTVs were on average 112.9% and 121.5% of prescribed dose, respectively. A very high degree of dose conformity was obtained, with CI, CN, and GI average values equal to 1.29, 0.80, and 3.63, respectively. The beam-on-time was on average 9.3 minutes, i.e., 0.36 min/Gy. The mean number of monitor units was 3162, i.e., 121.6 MU/Gy. Pretreatment verification (3%-3 mm) showed an optimal agreement with calculated values; mean γ value was 0.27 and 98.2% of measured points resulted with γ < 1. With a median follow-up of 16 months complete response was observed in 12/14 (86%) lesions; partial response was observed in 2/14 (14%) lesions. No radiation-induced liver disease (RILD) was observed in any patients as well no duodenal ulceration or esophagitis or gastric hemorrhage. In conclusion, this analysis demonstrated the feasibility and the appropriateness of high-dose single-fraction SRS-VMAT in liver metastases performed with Elekta VMAT and Ergo++ TPS. Preliminary clinical outcomes showed a high rate of local control and minimum incidence of acute toxicity.

  19. Canadian Optically-guided approach for Oral Lesions Surgical (COOLS trial: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Poh Catherine F

    2011-10-01

    Full Text Available Abstract Background Oral cancer is a major health problem worldwide. The 5-year survival rate ranges from 30-60%, and has remained unchanged in the past few decades. This is mainly due to late diagnosis and high recurrence of the disease. Of the patients who receive treatment, up to one third suffer from a recurrence or a second primary tumor. It is apparent that one major cause of disease recurrence is clinically unrecognized field changes which extend beyond the visible tumor boundary. We have previously developed an approach using fluorescence visualization (FV technology to improve the recognition of the field at risk surrounding a visible oral cancer that needs to be removed and preliminary results have shown a significant reduction in recurrence rates. Method/Design This paper describes the study design of a randomized, multi-centre, double blind, controlled surgical trial, the COOLS trial. Nine institutions across Canada will recruit a total of 400 patients with oral severe dysplasia or carcinoma in situ (N = 160 and invasive squamous cell carcinoma (N = 240. Patients will be stratified by participating institution and histology grade and randomized equally into FV-guided surgery (experimental arm or white light-guided surgery (control arm. The primary endpoint is a composite of recurrence at or 1 cm within the previous surgery site with 1 the same or higher grade histology compared to the initial diagnosis (i.e., the diagnosis used for randomization; or 2 further treatment due to the presence of severe dysplasia or higher degree of change at follow-up. This is the first randomized, multi-centre trial to validate the effectiveness of the FV-guided surgery. Discussion In this paper we described the strategies, novelty, and challenges of this unique trial involving a surgical approach guided by the FV technology. The success of the trial requires training, coordination, and quality assurance across multiple sites within Canada. The COOLS trial, an example of translational research, may result in reduced recurrence rates following surgical treatment of early-stage oral cancer with significant impacts on survival, morbidity, patients' quality of life and the cost to the health care system. Trial Registration Clinicaltrials.gov NCT01039298

  20. A Multiscale Adaptive Mesh Refinement Approach to Architectured Steel Specification in the Design of a Frameless Stressed Skin Structure

    DEFF Research Database (Denmark)

    Nicholas, Paul; Stasiuk, David; Nørgaard, Esben

    2015-01-01

    and material. Adaptive mesh refinement is used to support localised variance in resolution and information flow across these scales. The adaptation of mesh resolution is linked to structural analysis, panelisation, local geometric formation, connectivity, and the calculation of forming strains and material...

  1. An Integrated Modelling and Toolpathing Approach for a Frameless Stressed Skin Structure, Fabricated Using Robotic Incremental Sheet Forming

    DEFF Research Database (Denmark)

    Nicholas, Paul; Stasiuk, David; Nørgaard, Esben Clausen

    2016-01-01

    For structural assemblies that depend upon robotic incremental sheet forming (ISF) the rigidity, connectivity, customization and aesthetics play an important role for an integrated and accurate modeling process. Furthermore, it is critical to consider fabrication and forming parameters jointly...... with calculated and observed micro behaviour; the organisation and extraction of toolpaths; and rig setup logics for fabrication. Finally, the validity of these models is evaluated for structural performance, and for geometric accuracy at multiple scales....... with performance implications at material, element and structural scales. This paper briefly presents ISF as a method of fabrication, and introduces the context of structures where the skin plays an integral role. It describes the development of an integrated approach for the modelling and fabrication of Stressed...

  2. Actuality and Development of Fibre-optic Guided Missile%光纤制导导弹的现状与发展

    Institute of Scientific and Technical Information of China (English)

    刘方; 刘滨涛

    2005-01-01

    光纤制导(fibre-optic guidance)是融电视制导、光传感器、计算机智能化数据处理和控制技术等为一体,利用光纤作双向数据传输来实现图像制导的一种新型制导技术.由于光纤制导具有导线制导、无线电制导、红外制导、可见光制导以及激光制导等所不具备的独特优点,广泛应用于反直升机、反舰艇和反坦克光纤制导导弹.首先分析了国际上光纤制导导弹的现状,然后探讨了其在战术运用中的优势和不足,最后提出了下一步的发展趋势,对我国开展该项研究具有一定的现实意义.

  3. Nursing cooperation of frameless stereotactic operation by computer and robot%机器人辅助脑立体定向手术患者的护理

    Institute of Scientific and Technical Information of China (English)

    郝秋星

    2007-01-01

    目的 总结在"无框架脑立体定向手术"中的计算机与机器人的应用经验及护理配合经验,提出科学有效的工作方法,提高手术配合质量.方法 回顾分析246例手术的配合过程,分析影响手术精度的因素,规范护理操作程序.结果 本组手术过程顺利,平均误差<1.5 mm,无手术并发症发生.结论 掌握计算机相关知识及机器人操作技术,对于配合"无框架脑立体定向手术"具有重要意义;了解本学科新技术新业务,顺应医疗科学的发展,是每个护理人员面临的挑战.

  4. Frameless Stereotactic Insertion of Viewsite Brain Access System with Microscope-Mounted Tracking Device for Resection of Deep Brain Lesions: Technical Report.

    Science.gov (United States)

    White, Tim; Chakraborty, Shamik; Lall, Rohan; Fanous, Andrew A; Boockvar, John; Langer, David J

    2017-02-04

    The surgical management of deep brain tumors is often challenging due to the limitations of stereotactic needle biopsies and the morbidity associated with transcortical approaches. We present a novel microscopic navigational technique utilizing the Viewsite Brain Access System (VBAS) (Vycor Medical, Boca Raton, FL, USA) for resection of a deep parietal periventricular high-grade glioma as well as another glioma and a cavernoma with no related morbidity. The approach utilized a navigational tracker mounted on a microscope, which was set to the desired trajectory and depth. It allowed gentle continuous insertion of the VBAS directly to a deep lesion under continuous microscopic visualization, increasing safety by obviating the need to look up from the microscope and thus avoiding loss of trajectory. This technique has broad value for the resection of a variety of deep brain lesions.

  5. Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation

    Science.gov (United States)

    Wiersma, Rodney D.; Wen, Zhifei; Sadinski, Meredith; Farrey, Karl; Yenice, Kamil M.

    2010-01-01

    Stereotactic radiosurgery delivers radiation with great spatial accuracy. To achieve sub-millimeter accuracy for intracranial SRS, a head ring is rigidly fixated to the skull to create a fixed reference. For some patients, the invasiveness of the ring can be highly uncomfortable and not well tolerated. In addition, placing and removing the ring requires special expertise from a neurosurgeon, and patient setup time for SRS can often be long. To reduce the invasiveness, hardware limitations and setup time, we are developing a system for performing accurate head positioning without the use of a head ring. The proposed method uses real-time 6D optical position feedback for turning on and off the treatment beam (gating) and guiding a motor-controlled 3D head motion compensation stage. The setup consists of a central control computer, an optical patient motion tracking system and a 3D motion compensation stage attached to the front of the LINAC couch. A styrofoam head cast was custom-built for patient support and was mounted on the compensation stage. The motion feedback of the markers was processed by the control computer, and the resulting motion of the target was calculated using a rigid body model. If the target deviated beyond a preset position of 0.2 mm, an automatic position correction was performed with stepper motors to adjust the head position via the couch mount motion platform. In the event the target deviated more than 1 mm, a safety relay switch was activated and the treatment beam was turned off. The feasibility of the concept was tested using five healthy volunteers. Head motion data were acquired with and without the use of motion compensation over treatment times of 15 min. On average, test subjects exceeded the 0.5 mm tolerance 86% of the time and the 1.0 mm tolerance 45% of the time without motion correction. With correction, this percentage was reduced to 5% and 2% for the 0.5 mm and 1.0 mm tolerances, respectively.

  6. Development of a frameless stereotactic radiosurgery system based on real-time 6D position monitoring and adaptive head motion compensation

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, Rodney D; Wen Zhifei; Sadinski, Meredith; Farrey, Karl; Yenice, Kamil M [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637 (United States)], E-mail: rwiersma@uchicago.edu

    2010-01-21

    Stereotactic radiosurgery delivers radiation with great spatial accuracy. To achieve sub-millimeter accuracy for intracranial SRS, a head ring is rigidly fixated to the skull to create a fixed reference. For some patients, the invasiveness of the ring can be highly uncomfortable and not well tolerated. In addition, placing and removing the ring requires special expertise from a neurosurgeon, and patient setup time for SRS can often be long. To reduce the invasiveness, hardware limitations and setup time, we are developing a system for performing accurate head positioning without the use of a head ring. The proposed method uses real-time 6D optical position feedback for turning on and off the treatment beam (gating) and guiding a motor-controlled 3D head motion compensation stage. The setup consists of a central control computer, an optical patient motion tracking system and a 3D motion compensation stage attached to the front of the LINAC couch. A styrofoam head cast was custom-built for patient support and was mounted on the compensation stage. The motion feedback of the markers was processed by the control computer, and the resulting motion of the target was calculated using a rigid body model. If the target deviated beyond a preset position of 0.2 mm, an automatic position correction was performed with stepper motors to adjust the head position via the couch mount motion platform. In the event the target deviated more than 1 mm, a safety relay switch was activated and the treatment beam was turned off. The feasibility of the concept was tested using five healthy volunteers. Head motion data were acquired with and without the use of motion compensation over treatment times of 15 min. On average, test subjects exceeded the 0.5 mm tolerance 86% of the time and the 1.0 mm tolerance 45% of the time without motion correction. With correction, this percentage was reduced to 5% and 2% for the 0.5 mm and 1.0 mm tolerances, respectively.

  7. WE-A-19A-01: SRT I: Comparison of SRT Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G [UCSD Medical Center, La Jolla, CA (United States); Schlesinger, D [University of Virginia Health Systems, Charlottesville, VA (United States); Descovich, M [University of California San Francisco, San Francisco, CA (United States)

    2014-06-15

    Within the past several years, the field of radiosurgery has seen numerous technological enhancements, including new dedicated devices for stereotactic delivery, the use of re-locatable frames to facilitate fractionated delivery and the image guided frameless approaches. The goal of this symposium is to compare and contrast competing technologies for cranial SRS/SRT. The symposium will open with a review of the general concept of cranial SRS/SRT procedures as well as describe the key differences from conventional radiotherapy. The speakers will then review each of the delivery technique (Gamma Knife, CyberKnife and Conventional linear accelerator) in turn. The focus of each speaker will be to describe the general workflow of each SRS modality, indications and counterindications for treatment. To compare and contrast different technologies, 2–3 cases examples demonstrating interesting treatment situations and expected outcomes, a sample treatment plan (either live or pre-recorded with live commentary) demonstrating the treatment planning technique, and machine and patient-specific QA required for treatment (if applicable). Additionally, workflows and data describing the use of immobilization devices or tracking/monitoring during SRS/SRT delivery will also be discussed. The session will close with a roundtable discussion of methods to evaluate plan quality, and achievable technical and clinical goals for intracranial SRS. Learning Objectives: Understand the key differences between cranial SRS/SRT and conventional treatments. Review Gamma Knife, CyberKnife and Conventional Linac-based radiosurgery delivery techniques and quality assurance Compare and contrast treatment plans, treatment planning strategy and and quality assurance procedures for each technology. Be able to establish cranial SRS/SRT procedure with optimized quality assurance program for each technology.

  8. Attenuation of external elements in the calculation frame less radiosurgery system from Varian (Zmed); Atenuacion de elementos externos al calculo en el sistema frameless de radiocirugia de varian (ZMED)

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Ortega, J.; Ordonez Marquez, J.; Molina Lopez, Y.

    2011-07-01

    Zmed frame less system, marketed by Varian, is based on infrared detection of a localised with reflective spheres is fixed by a dental mold to the patient's head. In this work we have studied the dosimetric differences would be found if an arc radiosurgery pierced plastic bar overhang used for the treatment main difference between the two media. (Author)

  9. Screw Placement Accuracy and Outcomes following O-Arm-Navigated Atlantoaxial Fusion: A Feasibility Study

    National Research Council Canada - National Science Library

    Smith, Jacob D; Jack, Megan M; Harn, Nicholas R; Bertsch, Judson R; Arnold, Paul M

    2016-01-01

    .... Methods Between 2011 and 2014, seven patients underwent posterior atlantoaxial fusion using intraoperative frameless stereotactic O-arm Surgical Imaging and StealthStation Surgical Navigation System (Medtronic, Inc...

  10. The Compact Pulsed Hadron Source Construction Status

    CERN Document Server

    Wei, Jie; Cai, Jinchi; Chen, Huaibi; Cheng, Cheng; Du, Qiang; Du, Taibin; Feng, Qixi; Feng, Zhe; Gong, Hui; Guan, Xialing; Han, Xiaoxue; Huang, Tuchen; Huang, Zhifeng; Li, Renkai; Li, Wenqian; Loong, Chun-Keung; Tang, Chuanxiang; Tian, Yang; Wang, Xuewu; Xie, Xiaofeng; Xing, Qingzi; Xiong, Zhengfeng; Xu, Dong; Yang, Yigang; Zeng, Zhi; Zhang, Huayi; Zhang, Xiaozhang; Zheng, Shu-xin; Zheng, Zhihong; Zhong, Bin; Billen, James; Young, Lloyd; Fu, Shinian; Tao, Juzhou; Zhao, Yaliang; Guan, Weiqiang; He, Yu; Li, Guohua; Li, Jian; Zhang, Dong-sheng; Li, Jinghai; Liang, Tianjiao; Liu, Zhanwen; Sun, Liangting; Zhao, Hongwei; Shao, Beibei; Stovall, James

    2010-01-01

    This paper reports the design and construction status, technical challenges, and future perspectives of the proton-linac based Compact Pulsed Hadron Source (CPHS) at the Tsinghua University, Beijing, China

  11. 机器人无框架立体定向仪在顽固性癫痫定位和治疗方面的应用%To locate the epileptic onset zone and treat the intractable epilepsy by robot assistant frameless system

    Institute of Scientific and Technical Information of China (English)

    吴朝晖; 田增民; 赵全军; 张剑宁; 肖霞; 王红; 林鸿; 王福莉

    2013-01-01

    目的 探讨机器人辅助无框架立体定向系统置入深部电极和射频热凝毁损的方法及效果.方法 对7例额、颞发作间期存在痫样放电的顽固性癫痫患者,采用机器人辅助无框架立体定向系统经额向双侧颞叶内侧置入深部电极,记录深部电极脑电图.深部电极脑电图记录到颞叶内侧为临床发作或电发作起源灶者,遂行机器人立体定向系统经额入路射频热凝颞叶深部结构;并对6例同意进行神经干细胞移植者移植干细胞.结果 术后24 ~52个月,7例随访按照Engel分级系统Ⅰ级4例(其中Ⅰa级3例、Ⅰd级1例),Ⅳa级2例、Ⅳc级1例.未有术后神经功能明显下降.结论 机器人辅助立体定向系统置入深部电极、射频热凝毁损和移植神经干细胞安全、有效、方便、快捷,部分额、颞叶顽固性癫痫患者对立体定向射频热凝和神经干细胞移植治疗反应良好.

  12. Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

    Science.gov (United States)

    Ma, L.; Kwok, Y.; Chin, L. S.; Yu, C.; Regine, W. F.

    2005-11-01

    Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

  13. Comparative analyses of linac and Gamma Knife radiosurgery for trigeminal neuralgia treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L; Kwok, Y; Chin, L S; Yu, C; Regine, W F [University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

    2005-11-21

    Dedicated linac-based radiosurgery has been reported for trigeminal neuralgia treatments. In this study, we investigated the dose fall-off characteristics and setup error tolerance of linac-based radiosurgery as compared with standard Gamma Knife radiosurgery. In order to minimize the errors from different treatment planning calculations, consistent imaging registration, dose calculation and dose volume analysis methods were developed and implemented for both Gamma Knife and linac-based treatments. Intra-arc setup errors were incorporated into the treatment planning process of linac-based deliveries. The effects of intra-arc setup errors with increasing number of arcs were studied and benchmarked against Gamma Knife deliveries with and without plugging patterns. Our studies found equivalent dose fall-off properties between Gamma Knife and linac-based radiosurgery given a sufficient number of arcs (>7) and small intra-arc errors (<0.5 mm) were satisfied for linac-based deliveries. Increasing the number of arcs significantly decreased the variations in the dose fall-off curve at the low isodose region (e.g. from 40% to 10%) and also improved dose uniformity at the high isodose region (e.g. from 70% to 90%). As the number of arcs increased, the effects of intra-arc setup errors on the dose fall-off curves decreased. Increasing the number of arcs also reduced the integral dose to the distal normal brain tissues. In conclusion, linac-based radiosurgery produces equivalent dose fall-off characteristics to Gamma Knife radiosurgery with a high number of arcs. However, one must note the increased treatment time for a large number of arcs and isocentre accuracies.

  14. Contemporary methods of radiosurgery treatment with the Novalis linear accelerator system.

    Science.gov (United States)

    Chen, Joseph C T; Rahimian, Javad; Girvigian, Michael R; Miller, Michael J

    2007-01-01

    Radiosurgery has emerged as an indispensable component of the multidisciplinary approach to neoplastic, functional, and vascular diseases of the central nervous system. In recent years, a number of newly developed integrated systems have been introduced for radiosurgery and fractionated stereotactic radiotherapy treatments. These modern systems extend the flexibility of radiosurgical treatment in allowing the use of frameless image-guided radiation delivery as well as high-precision fractionated treatments. The Novalis linear accelerator system demonstrates adequate precision and reliability for cranial and extracranial radiosurgery, including functional treatments utilizing either frame-based or frameless image-guided methods.

  15. Intraoperative 3D Ultrasonography for Image-Guided Neurosurgery

    NARCIS (Netherlands)

    Letteboer, Marloes Maria Johanna

    2004-01-01

    Stereotactic neurosurgery has evolved dramatically in recent years from the original rigid frame-based systems to the current frameless image-guided systems, which allow greater flexibility while maintaining sufficient accuracy. As these systems continue to evolve, more applications are found, and i

  16. Evaluation of stereotactic body radiotherapy (SBRT) boost in the management of endometrial cancer.

    Science.gov (United States)

    Demiral, S; Beyzadeoglu, M; Uysal, B; Oysul, K; Kahya, Y Elcim; Sager, O; Dincoglan, F; Gamsiz, H; Dirican, B; Surenkok, S

    2013-01-01

    The purpose of this study is to evaluate the use of linear accelerator (LINAC)-based stereotactic body radiotherapy (SBRT) boost with multileaf collimator technique after pelvic radiotherapy (RT) in patients with endometrial cancer. Consecutive patients with endometrial cancer treated using LINAC-based SBRT boost after pelvic RT were enrolled in the study. All patients had undergone surgery including total abdominal hysterectomy and bilateral salpingo-oophorectomy ± pelvic/paraortic lymphadenectomy before RT. Prescribed external pelvic RT dose was 45 Gray (Gy) in 1.8 Gy daily fractions. All patients were treated with SBRT boost after pelvic RT. The prescribed SBRT boost dose to the upper two thirds of the vagina including the vaginal vault was 18 Gy delivered in 3 fractions with 1-week intervals. Gastrointestinal and genitourinary toxicity was assessed using the Common Terminology Criteria for Adverse Events version 3 (CTCAE v3).Between April 2010 and May 2011, 18 patients with stage I-III endometrial cancer were treated with LINAC-based SBRT boost after pelvic RT. At a median follow-up of 24 (8-26) months with magnetic resonance imaging (MRI) and gynecological examination, local control rate of the study group was 100 % with negligible acute and late toxicity.LINAC-based SBRT boost to the vaginal cuff is a feasible gynecological cancer treatment modality with excellent local control and minimal toxicity that may replace traditional brachytherapy boost in the management of endometrial cancer.

  17. Three-dimensional, computer simulated navigation in endoscopic neurosurgery

    Directory of Open Access Journals (Sweden)

    Roberta K. Sefcik, BHA

    2017-06-01

    Conclusion: Three-dimensional, frameless neuronavigation systems are useful in endoscopic neurosurgery to assist in the pre-operative planning of potential trajectories and to help localize the pathology of interest. Neuronavigation appears to be accurate to <1–2 mm without issues related to brain shift. Further work is necessary in the investigation of the effect of neuronavigation on operative time, cost, and patient-centered outcomes.

  18. Conference on Aerospace Transparent Materials and Enclosures Held in Monterey, California on 16-20 January 1989

    Science.gov (United States)

    1989-04-01

    and W. R. Pinnell , AFWAL/FDER, Wright-Patterson Air Force Base REPAIR AND RESTORATION OF COMBAT DAMAGE TRANSPARENCIES 19.1 G. Renieri and D. Kovensky...AFWAL/MLSE, Wright-Patterson Air Force Base FRAMELESS AIRCRAFT TRANSPARENCY TECHNOLOGY DEVELOPMENT 507 William R. Pinnell , AFWAL/FDER, Wright-Patterson...14) indicated that in all cases , the V-22 windshield had a higher or an equal resolution when compared to the A-6E production windshield. The pilots

  19. Radiosurgery with photon beams; Physical aspects and adequacy of linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Podgorsak, E.B.; Pla, M.; Souhami, L. (McGill University, Montreal (Canada). Department of Radiation Oncology); Pike, G.B.; Olivier, A. (McGill University, Montreal (Canada). Department of Neurosurgery)

    1990-03-01

    The question of the adequacy of isocentric linear accelerators (linacs) for use in radiosurgery is addressed. The general physical requirements for radiosurgery, mainly a high spatial and numerical accuracy of dose delivery, reasonable treatment time, and low skin and leakage dose as well as cost considerations are examined. Various linac-based procedures are analyzed in view of their ability to meet these requirements and are contrasted with the clinically proven system of the Gamma unit. It is shown that the linac-based multiple converging arcs techniques and the dynamic rotation meet the stringent physical requirements on dose delivery and are thus viable alternatives to radiosurgery with the commercially available and dedicated Gamma unit. (author). 15 refs.; 2 figs.; 1 tab.

  20. Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: Hypothalamic dose and endocrine outcomes.

    OpenAIRE

    Andrew eElson; Joseph eBovi; Kawaljeet eKaur; Diana eMaas; Grant eSinson; Chris eSchultz

    2014-01-01

    Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic-pituitary (HP) axis dysfunction.Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or Gamma Knife) on hypothalamic dose and correlate these with HP-Axis deficits after radiotherapy.Methods:Radiation plans of patients treated postoperatively for pituitary adenomas using Linac-based 3D Conformal Radiotherapy (CRT) ...

  1. Effect of Treatment Modality on the Hypothalamic–Pituitary Function of Patients Treated with Radiation Therapy for Pituitary Adenomas: Hypothalamic Dose and Endocrine Outcomes

    OpenAIRE

    Elson, Andrew; Bovi, Joseph; Kaur, Kawaljeet; Maas, Diana; Sinson, Grant; Schultz, Chris

    2014-01-01

    Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic–pituitary (HP) axis dysfunction. Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or gamma knife) on hypothalamic dose and correlate these with HP-axis deficits after radiotherapy. Methods: Radiation plans of patients treated post-operatively for pituitary adenomas using Linac-based 3D-conformal radiother...

  2. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  3. Optical wear monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kidane, Getnet S; Desilva, Upul P.; He, Chengli; Ulerich, Nancy H.

    2016-07-26

    A gas turbine includes first and second parts having outer surfaces located adjacent to each other to create an interface where wear occurs. A wear probe is provided for monitoring wear of the outer surface of the first part, and includes an optical guide having first and second ends, wherein the first end is configured to be located flush with the outer surface of the first part. A fiber bundle includes first and second ends, the first end being located proximate to the second end of the optical guide. The fiber bundle includes a transmit fiber bundle comprising a first plurality of optical fibers coupled to a light source, and a receive fiber bundle coupled to a light detector and configured to detect reflected light. A processor is configured to determine a length of the optical guide based on the detected reflected light.

  4. Deep Brain Stimulation for Essential Vocal Tremor: A Technical Report.

    Science.gov (United States)

    Ho, Allen L; Choudhri, Omar; Sung, C Kwang; DiRenzo, Elizabeth E; Halpern, Casey H

    2015-03-01

    Essential vocal tremor (EVT) is the presence of a tremulous voice that is commonly associated with essential tremor. Patients with EVT often report a necessary increase in vocal effort that significantly worsens with stress and anxiety and can significantly impact quality of life despite optimal medical and behavioral treatment options. Deep brain stimulation (DBS) has been proposed as an effective therapy for vocal tremor, but very few studies exist in the literature that comprehensively evaluate the efficacy of DBS for specifically addressing EVT. We present a technical report on our multidisciplinary, comprehensive operative methodology for treatment of EVT with frameless, awake deep brain stimulation (DBS).

  5. Low cost solar array project production process and equipment task: A Module Experimental Process System Development Unit (MEPSDU)

    Science.gov (United States)

    1981-01-01

    Several major modifications were made to the design presented at the PDR. The frame was deleted in favor of a "frameless" design which will provide a substantially improved cell packing factor. Potential shaded cell damage resulting from operation into a short circuit can be eliminated by a change in the cell series/parallel electrical interconnect configuration. The baseline process sequence defined for the MEPSON was refined and equipment design and specification work was completed. SAMICS cost analysis work accelerated, format A's were prepared and computer simulations completed. Design work on the automated cell interconnect station was focused on bond technique selection experiments.

  6. Development of Device Quality Nonlinear Optical Materials and Definition of Mechanisms of Optical Nonlinearity

    Science.gov (United States)

    1994-09-01

    Pasillas, P.; Hoover, J.; Lindsay, G.; Henry, R. J. Appi. Phys. 1990, 68 , 456. 139. Hampsch, H.; Yang, J.; Wong, G.; Torkelson, J. Macromolecules 1990, 23...New York, 1992. 295. Syms, R.; Cozens, J. Optical Guided Waves and Devices, McGraw Hill: New York, 1992. 296. Marcuse , D. Theory of Optical Dielectric

  7. Guided Acoustic and Optical Waves in Silicon-on-Insulator for Brillouin Scattering and Optomechanics

    Science.gov (United States)

    2016-08-01

    environment, they also isolate devices from heat-dissipating thermal linkages and on-chip electronics. The intuition of “index-guided” confinement of...coupling. Consider the optical guided modes for 100 nm wide fins spaced 40 nm apart in 340 nm thick silicon shown in Figure 2(b). For these

  8. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

    2005-02-28

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  9. Effect of treatment modality on the hypothalamic-pituitary function of patients treated with radiation therapy for pituitary adenomas: Hypothalamic dose and endocrine outcomes.

    Directory of Open Access Journals (Sweden)

    Andrew eElson

    2014-04-01

    Full Text Available Background: Both fractionated external beam radiotherapy and single fraction radiosurgery for pituitary adenomas are associated with the risk of hypothalamic-pituitary (HP axis dysfunction.Objective: To analyze the effect of treatment modality (Linac, TomoTherapy, or Gamma Knife on hypothalamic dose and correlate these with HP-Axis deficits after radiotherapy.Methods:Radiation plans of patients treated postoperatively for pituitary adenomas using Linac-based 3D Conformal Radiotherapy (CRT (n=11, TomoTherapy-based Intensity Modulated Radiation Therapy (IMRT (n=10, or Gamma Knife Stereotactic Radiosurgery (SRS(n=12 were retrospectively reviewed. Dose to the hypothalamus was analyzed and postradiotherapy hormone function including growth hormone (GH, thyroid (TSH, adrenal (ACTH, prolactin (PRL, and gonadotropins (FSH/LH were assessed. Results:Post-radiation, 13 of 27 (48% patients eligible for analysis developed at least one new hormone deficit, of which 8 of 11 (72% occurred in the Linac group, 4 of 8 (50% occurred in the TomoTherapy group, and 1 of 8 (12.5% occurred in the Gamma Knife group. Compared with fractionated techniques, Gamma Knife showed improved hypothalamic sparing for DMax Hypo, and V12Gy. For fractionated modalities, TomoTherapy showed improved dosimetric characteristics over Linac-based treatment with hypothalamic DMean (44.8 Gy vs. 26.8 Gy p=0.02, DMax (49.8 Gy vs. 39.1 Gy p=0.04, and V12Gy (100% vs. 76% p=0.004.Conclusion:Maximal dosimetric avoidance of the hypothalamus was achieved using Gamma Knife-based radiosurgery followed by TomoTherapy-based IMRT, and Linac-based 3D conformal radiation therapy, respectively.

  10. Testing a Low-Influence Spindle Drive Motor

    Energy Technology Data Exchange (ETDEWEB)

    Hale, L; Wulff, T; Sedgewick, J

    2003-11-05

    Precision spindles used for diamond turning and other applications requiring low error motion generally require a drive system that ideally applies a pure torque to the rotating spindle. Frequently a frameless motor, that is, one without its own bearings, is directly coupled to the spindle to make a compact and simple system having high resonant frequencies. Although in addition to delivering drive torque, asymmetries in the motor cause it to generate disturbance loads (forces and moments) which influence the spindle error motion of the directly coupled system. This paper describes the tests and results for a particular frameless, brushless DC motor that was originally developed for military and space applications requiring very low torque ripple. Because the construction of the motor should also lead to very low disturbance loads, it was selected for use on a new diamond turning and grinding machine under developed at Lawrence Livermore National Laboratory. The level of influence for this motor-spindle combination is expected to be of order one nanometer for radial and axial error motion.

  11. A 1.2 THz Planar Tripler Using GaAs Membrane Based Chips

    Science.gov (United States)

    Bruston, J.; Maestrini, A.; Pukala, D.; Martin, S.; Nakamura, B.; Mehdi, I.

    2001-01-01

    Fabrication technology for submillimeter-wave monolithic circuits has made tremendous progress in recent years and it is now possible to fabricate sub-micron GaAs Schottky devices on a number of substrate types, such as membranes, frame-less membranes or substrateless circuits. These new technologies allow designers to implement very high frequency circuits, either Schottky mixers or multipliers, in a radically new manner. This paper will address the design, fabrication, and preliminary results of a 1.2 THz planar tripler fabricated on a GaAs frame-less membrane, the concept of which was described previously. The tripler uses a diode pair in an antiparallel configuration similar to designs used at lower frequency. To date, this tripler has produced a peak output power of 80 microW with 0.9% efficiency at room temperature (at 1126 GHz). The measured fix-tuned 3 dB bandwidth is about 3.5%. When cooled, the output power reached a peak of 195 microW at 120 K and 250 microW at 50 K. The ease with which this circuit was implemented along with the superb achieved performance indicates that properly designed planar devices such as this tripler can now usher in a new era of practical very high frequency multipliers.

  12. Practical Advice for Emergency IUD Contraception in Young Women

    Directory of Open Access Journals (Sweden)

    Norman D. Goldstuck

    2015-01-01

    Full Text Available Too few women are aware of the very high efficacy of intrauterine copper devices (IUDs to prevent pregnancy after unprotected intercourse. Women who frequently engage in unprotected intercourse or seek emergency contraception (EC are at high risk of unplanned pregnancy and possible abortion. It is therefore important that these women receive precise and accurate information about intrauterine devices as they may benefit from using an IUD for EC as continuing contraception. Copper IUDs should be used as first choice options given their rapid onset of action and their long-term contraceptive action which require minimal thought or intervention on the part of the user. In the United States, there is only one copper IUD presently available which limits treatment options. There are numerous copper IUDs available for use in EC, however, their designs and size are not always optimal for use in nulliparous women or women with smaller or narrower uteruses. Utilization of frameless IUDs which do not require a larger transverse arm for uterine retention may have distinct advantages, particularly in young women, as they will be suitable for use in all women irrespective of uterine size. This paper provides practical information on EC use with emphasis on the use of the frameless IUD.

  13. Practical Advice for Emergency IUD Contraception in Young Women.

    Science.gov (United States)

    Goldstuck, Norman D; Wildemeersch, Dirk

    2015-01-01

    Too few women are aware of the very high efficacy of intrauterine copper devices (IUDs) to prevent pregnancy after unprotected intercourse. Women who frequently engage in unprotected intercourse or seek emergency contraception (EC) are at high risk of unplanned pregnancy and possible abortion. It is therefore important that these women receive precise and accurate information about intrauterine devices as they may benefit from using an IUD for EC as continuing contraception. Copper IUDs should be used as first choice options given their rapid onset of action and their long-term contraceptive action which require minimal thought or intervention on the part of the user. In the United States, there is only one copper IUD presently available which limits treatment options. There are numerous copper IUDs available for use in EC, however, their designs and size are not always optimal for use in nulliparous women or women with smaller or narrower uteruses. Utilization of frameless IUDs which do not require a larger transverse arm for uterine retention may have distinct advantages, particularly in young women, as they will be suitable for use in all women irrespective of uterine size. This paper provides practical information on EC use with emphasis on the use of the frameless IUD.

  14. A treatment planning comparison between modulated tri-cobalt-60 teletherapy and linear accelerator–based stereotactic body radiotherapy for central early-stage non−small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Merna, Catherine; Rwigema, Jean-Claude M.; Cao, Minsong; Wang, Pin-Chieh; Kishan, Amar U.; Michailian, Argin; Lamb, James; Sheng, Ke; Agazaryan, Nzhde; Low, Daniel A.; Kupelian, Patrick; Steinberg, Michael L.; Lee, Percy, E-mail: percylee@mednet.ucla.edu

    2016-04-01

    We evaluated the feasibility of planning stereotactic body radiotherapy (SBRT) for large central early-stage non−small cell lung cancer with a tri-cobalt-60 (tri-{sup 60}Co) system equipped with real-time magnetic resonance imaging (MRI) guidance, as compared to linear accelerator (LINAC)–based SBRT. In all, 20 patients with large central early-stage non−small cell lung cancer who were treated between 2010 and 2015 with LINAC-based SBRT were replanned using a tri-{sup 60}Co system for a prescription dose of 50 Gy in 4 fractions. Doses to organs at risk were evaluated based on established MD Anderson constraints for central lung SBRT. R{sub 100} values were calculated as the total tissue volume receiving 100% of the dose (V{sub 100}) divided by the planning target volume and compared to assess dose conformity. Dosimetric comparisons between LINAC-based and tri-{sup 60}Co SBRT plans were performed using Student's t-test and Wilcoxon Ranks test. Blinded reviews by radiation oncologists were performed to assess the suitability of both plans for clinical delivery. The mean planning target volume was 48.3 cc (range: 12.1 to 139.4 cc). Of the tri-{sup 60}Co SBRT plans, a mean 97.4% of dosimetric parameters per patient met MD Anderson dose constraints, whereas a mean 98.8% of dosimetric parameters per patient were met with LINAC-based SBRT planning (p = 0.056). R{sub 100} values were similar between both plans (1.20 vs 1.21, p = 0.79). Upon blinded review by 4 radiation oncologists, an average of 90% of the tri-{sup 60}Co SBRT plans were considered acceptable for clinical delivery compared with 100% of the corresponding LINAC-based SBRT plans (p = 0.17). SBRT planning using the tri-{sup 60}Co system with built-in MRI is feasible and achieves clinically acceptable plans for most central lung patients, with similar target dose conformity and organ at risk dosimetry. The added benefit of real-time MRI-guided therapy may further optimize tumor targeting while

  15. Plan Quality and Treatment Efficiency for Radiosurgery to Multiple Brain Metastases: Non-Coplanar RapidArc vs. Gamma Knife

    OpenAIRE

    Liu, Haisong; Andrews, David W.; Evans, James J.; Werner-Wasik, Maria; Yan YU; Dicker, Adam Paul; Shi, Wenyin

    2016-01-01

    Objectives This study compares the dosimetry and efficiency of two modern radiosurgery [stereotactic radiosurgery (SRS)] modalities for multiple brain metastases [Gamma Knife (GK) and LINAC-based RapidArc/volumetric modulated arc therapy], with a special focus on the comparison of low-dose spread. Methods Six patients with three or four small brain metastases were used in this study. The size of targets varied from 0.1 to 10.5 cc. SRS doses were prescribed according to the size of ...

  16. Plan Quality and Treatment Efficiency for Radiosurgery to Multiple Brain Metastases: Non-Coplanar RapidArc vs Gamma Knife

    OpenAIRE

    Haisong eLiu; Andrews, David W.; Evans, James J.; Maria eWerner-wasik; Yan eYu; Adam Paul Dicker; Wenyin eShi

    2016-01-01

    Objectives: This study compares the dosimetry and efficiency of two modern radiosurgery (SRS) modalities for multiple brain metastases (Gamma Knife and LINAC-based RapidArc/volumetric modulated arc therapy), with a special focus on the comparison of low dose spread.Methods: Six patients with three or four small brain metastases were used in this study. The size of targets varied from 0.1 ~ 10.5 cc. SRS doses were prescribed according to size of lesions. SRS plans were made using both Gamma Kn...

  17. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  18. Symposium on electron linear accelerators in honor of Richard B. Neal's 80th birthday: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Siemann, R.H. [ed.

    1998-07-01

    The papers presented at the conference are: (1) the construction of SLAC and the role of R.B. Neal; (2) symposium speech; (3) lessons learned from the SLC; (4) alternate approaches to future electron-positron linear colliders; (5) the NLC technical program; (6) advanced electron linacs; (7) medical uses of linear accelerators; (8) linac-based, intense, coherent X-ray source using self-amplified spontaneous emission. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  19. Measurement of photoneutron spectrum at Pohang Neutron Facility

    CERN Document Server

    Kim, G N; Lee, Y S; Skoy, V; Cho, M H; Ko, I S; Namkung, W; Lee, D W; Kim, H D; Ko, S K; Park, S H; Kim, D S; Ro, T I; Min, Y G

    2002-01-01

    The Pohang Neutron Facility, an electron linear accelerator (linac) based pulsed neutron facility, was constructed for nuclear data production in Korea. It consists of an electron linac, a water-cooled Ta target with a water moderator, and a time-of-flight path with an 11 m length. The neutron energy spectra are measured for different water levels inside the moderator and compared with calculations by the Monte Carlo N-Particle transport code. The optimum size of the water moderator is determined based on these results.

  20. Ion tracking in photocathode rf guns

    Directory of Open Access Journals (Sweden)

    John W. Lewellen

    2002-02-01

    Full Text Available Projected next-generation linac-based light sources, such as PERL or the TESLA free-electron laser, generally assume, as essential components of their injector complexes, long-pulse photocathode rf electron guns. These guns, due to their design rf pulse durations of many milliseconds to continuous wave, may be more susceptible to ion bombardment damage of their cathodes than conventional rf guns, which typically use rf pulses of microsecond duration. This paper explores this possibility in terms of ion propagation within the gun, and presents a basis for future study of the subject.

  1. Intense ultrashort pulse generation using the JAERI far-infrared free electron laser

    CERN Document Server

    Nagai, R; Nishimori, N; Kikuzawa, N; Sawamura, M; Minehara, E J

    2002-01-01

    An intense ultrashort optical pulse has been quasi-continuously generated using a superconducting RF linac-based free-electron laser at a wavelength of 22.5 mu m. The pulse shape and width are measured by second-order optical autocorrelation with a birefringent Te crystal. At synchronism of the optical resonator, the pulse shape is a smooth single pulse with an FWHM width of 255 fs and energy of 74 mu J. A train of subpulses is developed by increasing the desynchronism of the optical resonator. The measured results are in good agreement with numerical simulation.

  2. The 4th Generation Light Source at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Albert Grippo; Christopher Gould; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; Kevin Jordan; John Klopf; Steven Moore; George Neil; Thomas Powers; Joseph Preble; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Shukui Zhang; Gwyn Williams

    2007-04-25

    A number of "Grand Challenges" in Science have recently been identified in reports from The National Academy of Sciences, and the U.S. Dept. of Energy, Basic Energy Sciences. Many of these require a new generation of linac-based light source to study dynamical and non-linear phenomena in nanoscale samples. In this paper we present a summary of the properties of such light sources, comparing them with existing sources, and then describing in more detail a specific source at Jefferson Lab. Importantly, the JLab light source has developed some novel technology which is a critical enabler for other new light sources.

  3. An Injector Test Facility for the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Colby, E., (ed.); /SLAC

    2007-03-14

    SLAC is in the privileged position of being the site for the world's first 4th generation light source as well as having a premier accelerator research staff and facilities. Operation of the world's first x-ray free electron laser (FEL) facility will require innovations in electron injectors to provide electron beams of unprecedented quality. Upgrades to provide ever shorter wavelength x-ray beams of increasing intensity will require significant advances in the state-of-the-art. The BESAC 20-Year Facilities Roadmap identifies the electron gun as ''the critical enabling technology to advance linac-based light sources'' and recognizes that the sources for next-generation light sources are ''the highest-leveraged technology'', and that ''BES should strongly support and coordinate research and development in this unique and critical technology''.[1] This white paper presents an R&D plan and a description of a facility for developing the knowledge and technology required to successfully achieve these upgrades, and to coordinate efforts on short-pulse source development for linac-based light sources.

  4. Perineural spread of cutaneous malignancy to the brain: a review of the literature and five patients treated with stereotactic radiotherapy.

    Science.gov (United States)

    Fowler, B Zach; Crocker, Ian R; Johnstone, Peter A S

    2005-05-15

    The retrospective analysis was performed to investigate the role of stereotactic radiotherapy (SRT) techniques for patients with intracranial perineural spread (PNS) of a primary cutaneous malignancy. Five patients were identified who received SRT from 1993 to 2003 for cutaneous malignancies with intracranial PNS to the cavernous sinus (n = 3) or Meckel's cave (n = 2). Patients were treated with GammaKnife stereotactic radiosurgery (n = 2), linear accelerator (linac)-based fractionated SRT (n = 2), or linac-based stereotactic radiosurgery (n = 1). The median overall survival (OS) periods from diagnoses of cutaneous malignancy and intracranial PNS were 63.0 months (range, 22.0-102.2 months) and 25.5 months (range, 22.0-55.2 months), respectively. The median OS from SRT was 24.2 months (range, 19.5-53.2 months). One patient was alive and without evidence of disease at 53 months of follow-up. The median durations of local and regional control from SRT were 19.5 months (range, 1.5-53.2 months) and 7.0 months (range, 1.5-53.2 months), respectively. Previous reports generally have recommended that patients with intracranial PNS receive palliative external-beam radiotherapy. Results from the current study suggest that some of these patients may have prolonged survival, or even may be cured. Judicious use of SRT should be considered in their management.

  5. Indoor Soiling Method and Outdoor Statistical Risk Analysis of Photovoltaic Power Plants

    Science.gov (United States)

    Rajasekar, Vidyashree

    This is a two-part thesis. Part 1 presents an approach for working towards the development of a standardized artificial soiling method for laminated photovoltaic (PV) cells or mini-modules. Construction of an artificial chamber to maintain controlled environmental conditions and components/chemicals used in artificial soil formulation is briefly explained. Both poly-Si mini-modules and a single cell mono-Si coupons were soiled and characterization tests such as I-V, reflectance and quantum efficiency (QE) were carried out on both soiled, and cleaned coupons. From the results obtained, poly-Si mini-modules proved to be a good measure of soil uniformity, as any non-uniformity present would not result in a smooth curve during I-V measurements. The challenges faced while executing reflectance and QE characterization tests on poly-Si due to smaller size cells was eliminated on the mono-Si coupons with large cells to obtain highly repeatable measurements. This study indicates that the reflectance measurements between 600-700 nm wavelengths can be used as a direct measure of soil density on the modules. Part 2 determines the most dominant failure modes of field aged PV modules using experimental data obtained in the field and statistical analysis, FMECA (Failure Mode, Effect, and Criticality Analysis). The failure and degradation modes of about 744 poly-Si glass/polymer frameless modules fielded for 18 years under the cold-dry climate of New York was evaluated. Defect chart, degradation rates (both string and module levels) and safety map were generated using the field measured data. A statistical reliability tool, FMECA that uses Risk Priority Number (RPN) is used to determine the dominant failure or degradation modes in the strings and modules by means of ranking and prioritizing the modes. This study on PV power plants considers all the failure and degradation modes from both safety and performance perspectives. The indoor and outdoor soiling studies were jointly

  6. Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Yi; Wu, J.; Cai, Y.; Chao, A.W.; Fawley, W.M.; Frisch, J.; Huang, Z.; Nuhn, H.-D.; /SLAC; Pellegrini, C.; /SLAC /UCLA; Reiche, S.; /PSI, Villigen

    2012-02-15

    Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered after the FEL saturation. By use of ray equation approximation to combine the one-dimensional FEL theory and optical guiding approach, an explicit physical model is built to provide insight to the mechanism of the electron-radiation coherent interaction with variable undulator parameters as well as electron beam radius. The contribution of variation in electron beam radius and related transverse effects are studied based on the presented model and numerical simulation. Taking a recent studied terawatt, 120 m long tapered FEL as an example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

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

    Science.gov (United States)

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

    2013-01-01

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

  8. Vocal Tremor: Novel Therapeutic Target for Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Vinod K. Ravikumar

    2016-10-01

    Full Text Available Tremulous voice is characteristically associated with essential tremor, and is referred to as essential vocal tremor (EVT. Current estimates suggest that up to 40% of individuals diagnosed with essential tremor also present with EVT, which is associated with an impaired quality of life. Traditional EVT treatments have demonstrated limited success in long-term management of symptoms. However, voice tremor has been noted to decrease in patients receiving deep brain stimulation (DBS with the targeting of thalamic nuclei. In this study, we describe our multidisciplinary procedure for awake, frameless DBS with optimal stimulation targets as well as acoustic analysis and laryngoscopic assessment to quantify tremor reduction. Finally, we investigate the most recent clinical evidence regarding the procedure.

  9. Sum rates of asynchronous GFDMA and SC-FDMA for 5G uplink

    Directory of Open Access Journals (Sweden)

    Woojin Park

    2015-12-01

    Full Text Available The fifth generation (5G of mobile communication envisions ultralow latency less than 1 ms for radio interface. To this end, frameless asynchronous multiple access may be needed to allow users to transmit instantly without waiting for the next frame start. In this paper, generalized frequency division multiple-access (GFDMA, one of the promising multiple-access candidates for 5G mobile, is compared with the conventional single-carrier FDMA (SC-FDMA in terms of the uplink sum rate when both techniques are adapted for the asynchronous scenario. In particular, a waveform windowing technique is applied to both schemes to mitigate the inter-user interference due to non-zero out-of-band emission.

  10. Multi-view display module employing MEMS projector array.

    Science.gov (United States)

    Takaki, Yasuhiro; Takenaka, Hiromitsu; Morimoto, Yasuhiro; Konuma, Osamu; Hirabayashi, Kenji

    2012-12-17

    A frameless multi-view display module that consists of an array of microelectromechanical system (MEMS) based projectors, a sparse lenticular lens, and a vertical diffuser is proposed to provide a large-screen autostereoscopic display. The projectors are positioned in a horizontal vector form or in a matrix form in front of the transfer screen in order to produce the same number of three-dimensional (3D) pixels in each cylindrical lens constituting the lenticular lens to increase the horizontal resolution of the module. The projectors generate a slanted two-dimensional array of dots on the vertical diffuser to provide a large number of viewpoints. The experimental display system was constructed using four projectors. The system had a 3D resolution of 160 × 120, and it provided 64 views. The screen size was 14.4 in.

  11. Stereotactic Radiosurgery as Part of Multimodal Treatment in a Bulky Leptomeningeal Recurrence of Breast Cancer.

    Science.gov (United States)

    Bertke, Matthew H; Burton, Eric C; Shaughnessy, Joseph N

    2016-03-08

    Breast cancer metastatic to the brain and/or leptomeningeal spread of disease is a frequently encountered clinical situation, especially given the extended course of disease in these patients. Systemic therapies can often effectively prolong extracranial disease control, making effective strategies to control central nervous system-based disease even more critical. We present a case of bulky leptomeningeal relapse of breast cancer in the setting of prior whole brain radiation therapy. In order to treat the patient's bulky disease and leptomeningeal spread while avoiding the potential toxicities of repeat whole brain radiation, the patient was treated with frameless stereotactic radiosurgery and intrathecal chemotherapy. This is the first report of this treatment approach for leptomeningeal relapse of breast cancer. The patient had an excellent response to treatment and durable intracranial control.

  12. The Ripple Pond: Enabling Spiking Networks to See

    Directory of Open Access Journals (Sweden)

    Saeed eAfshar

    2013-11-01

    Full Text Available We present the biologically inspired Ripple Pond Network (RPN, a simply connected spiking neural network which performs a transformation converting two dimensional images to one dimensional temporal patterns suitable for recognition by temporal coding learning and memory networks. The RPN has been developed as a hardware solution linking previously implemented neuromorphic vision and memory structures such as frameless vision sensors and neuromorphic temporal coding spiking neural networks. Working together such systems are potentially capable of delivering end-to-end high-speed, low-power and low-resolution recognition for mobile and autonomous applications where slow, highly sophisticated and power hungry signal processing solutions are ineffective. Key aspects in the proposed approach include utilising the spatial properties of physically embedded neural networks and propagating waves of activity therein for information processing, using dimensional collapse of imagery information into amenable temporal patterns and the use of asynchronous frames for information binding.

  13. Accuracy of spinal navigation for Magerl-screws

    CERN Document Server

    Herz, T

    2001-01-01

    Study design: assessment of the accuracy of frameless stereotactic navigation at the second cervical vertebra. Objectives: to assess the influence of the protocol of preoperative CT-scan and the registration technique on the accuracy of navigation for implanting Magerl-screws. Summary of background data: the use of navigation systems for implanting Magerl-screws could help to decrease the risk of complications and to reduce the required skin incision. Two parameters conceivably affecting the accuracy are the protocol of the preoperative CT-scan and the registration technique. Methods: four cervical spine segments of human cadavers were scanned with two different protocols (3 mm slice thickness/2 mm table increment, 1 mm slice thickness/1 mm table increment). Registration was performed either based on anatomical landmarks or using a specially designed percutaneous registration device. For the accuracy-check, the pointer tip was exactly placed on markers. The distance between the pointer and the marker displaye...

  14. Development of Cu(In,Ga)Se2 Test Coupons for Potential Induced Degradation Studies

    Energy Technology Data Exchange (ETDEWEB)

    Contreras, Miguel A.; Hacke, Peter; Repins, Ingrid

    2016-11-21

    We report on the design, fabrication and accelerated testing of fully encapsulated small area coupons (approximately 7.5cm x 7.5 cm) for the purpose of researching potential induced degradation in Cu(In, Ga)Se2 based PV modules. The fabrication of these coupons enables the study of the solar cells and the materials used in PV module manufacturing such as top and bottom glass covers of different composition (soda-lime glass, high temperature glass, alkaline-free glass, etc), plastic-based top covers, ethylene vinyl acetate and edge seal encapsulation materials. The coupons can also be used to emulate framed and frameless modules that utilize either monolithically interconnected modules or singular cell type of modules. The design of the coupons, their fabrication, the materials used and their testing for 1000 hours under 85 degrees C and 85% RH conditions are presented.

  15. Two-dimensional pixel array image sensor for protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Beuville, E.; Beche, J.-F.; Cork, C. [and others

    1996-07-01

    A 2D pixel array image sensor module has been designed for time resolved Protein Crystallography. This smart pixels detector significantly enhances time resolved Laue Protein crystallography by two to three orders of magnitude compared to existing sensors like films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow one to study the evolution of structural changes that occur within the protein as a function of time. This detector will also considerably accelerate data collection in static Laue or monochromatic crystallography and make better use of the intense beam delivered by synchrotron light sources. The event driven pixel array detectors, based on the column Architecture, can provide multiparameter information (energy discrimination, time), with sparse and frameless readout without significant dead time. The prototype module consists of a 16x16 pixel diode array bump-bonded to the integrated circuit. The detection area is 150x150 square microns.

  16. Effect of residue hematoma volume on inflammation factors in hypertensive intracranial hemorrhage

    Directory of Open Access Journals (Sweden)

    You-san ZHANG

    2016-10-01

    Full Text Available Objectives  In this study, the relationships of residue hematoma volume to brain edema and inflammation factors were studied after intracerebral hematoma was evacuated with a frameless stereotactic aspiration. Methods  Eighty-nine patients with hypertensive intracerebral hemorrhage (ICH were treated by frameless stereotactic aspiration. According to residual volume of the hematoma, the patients were divided into gross-total removal of hematoma (GTRH (≤5ml and sub-total removal of hematoma (STRH (≥10ml groups after the operation. The pre-operative and postoperative data of the patients were compared between the two groups. The pre-operative data included age, sex, hematoma volume, time interval from the ictus to the operation, and Glasgow Coma Scale (GCS scores. The post-operative information included edema grade, level of thromboxane B2 (TXB2, 6-keto-prostaglandin F1α(6-K-PGF1α, tumor necrosis factor-α(TNF-α and endothelin (ET in hematoma cavity or cerebral spinal fluid (CSF. Results  There were 46 patients in GTRH group and 43 in STRH group respectively. There was no statistical difference in the pre-operative data between the two groups. The levels of TXB2, 6-K-PGF1α, TNF-αand ET were significantly lower in the GTRH group than in the STRH group at different post-operative time points. There was a significant difference between the two groups. The post-operative CT scan at different time points showed that the brain edema grades were better in the GTRH group than in the STRH group. Conclusions  GTRH is helpful for decreasing ICH-induced injury to brain tissue, which is related to decreased perihematomal edema formation and secondary injury by coagulation end products activated inflammatory cascade. DOI: 10.11855/j.issn.0577-7402.2016.09.12

  17. A new tool for touch-free patient registration for robot-assisted intracranial surgery: application accuracy from a phantom study and a retrospective surgical series.

    Science.gov (United States)

    Cardinale, Francesco; Rizzi, Michele; d'Orio, Piergiorgio; Casaceli, Giuseppe; Arnulfo, Gabriele; Narizzano, Massimo; Scorza, Davide; De Momi, Elena; Nichelatti, Michele; Redaelli, Daniela; Sberna, Maurizio; Moscato, Alessio; Castana, Laura

    2017-05-01

    OBJECTIVE The purpose of this study was to compare the accuracy of Neurolocate frameless registration system and frame-based registration for robotic stereoelectroencephalography (SEEG). METHODS The authors performed a 40-trajectory phantom laboratory study and a 127-trajectory retrospective analysis of a surgical series. The laboratory study was aimed at testing the noninferiority of the Neurolocate system. The analysis of the surgical series compared Neurolocate-based SEEG implantations with a frame-based historical control group. RESULTS The mean localization errors (LE) ± standard deviations (SD) for Neurolocate-based and frame-based trajectories were 0.67 ± 0.29 mm and 0.76 ± 0.34 mm, respectively, in the phantom study (p = 0.35). The median entry point LE was 0.59 mm (interquartile range [IQR] 0.25-0.88 mm) for Neurolocate-registration-based trajectories and 0.78 mm (IQR 0.49-1.08 mm) for frame-registration-based trajectories (p = 0.00002) in the clinical study. The median target point LE was 1.49 mm (IQR 1.06-2.4 mm) for Neurolocate-registration-based trajectories and 1.77 mm (IQR 1.25-2.5 mm) for frame-registration-based trajectories in the clinical study. All the surgical procedures were successful and uneventful. CONCLUSIONS The results of the phantom study demonstrate the noninferiority of Neurolocate frameless registration. The results of the retrospective surgical series analysis suggest that Neurolocate-based procedures can be more accurate than the frame-based ones. The safety profile of Neurolocate-based registration should be similar to that of frame-based registration. The Neurolocate system is comfortable, noninvasive, easy to use, and potentially faster than other registration devices.

  18. Analytical Design Package (ADP2): A computer aided engineering tool for aircraft transparency design

    Science.gov (United States)

    Wuerer, J. E.; Gran, M.; Held, T. W.

    1994-01-01

    The Analytical Design Package (ADP2) is being developed as a part of the Air Force Frameless Transparency Program (FTP). ADP2 is an integrated design tool consisting of existing analysis codes and Computer Aided Engineering (CAE) software. The objective of the ADP2 is to develop and confirm an integrated design methodology for frameless transparencies, related aircraft interfaces, and their corresponding tooling. The application of this methodology will generate high confidence for achieving a qualified part prior to mold fabrication. ADP2 is a customized integration of analysis codes, CAE software, and material databases. The primary CAE integration tool for the ADP2 is P3/PATRAN, a commercial-off-the-shelf (COTS) software tool. The open architecture of P3/PATRAN allows customized installations with different applications modules for specific site requirements. Integration of material databases allows the engineer to select a material, and those material properties are automatically called into the relevant analysis code. The ADP2 materials database will be composed of four independent schemas: CAE Design, Processing, Testing, and Logistics Support. The design of ADP2 places major emphasis on the seamless integration of CAE and analysis modules with a single intuitive graphical interface. This tool is being designed to serve and be used by an entire project team, i.e., analysts, designers, materials experts, and managers. The final version of the software will be delivered to the Air Force in Jan. 1994. The Analytical Design Package (ADP2) will then be ready for transfer to industry. The package will be capable of a wide range of design and manufacturing applications.

  19. Development of stereotactic mass spectrometry for brain tumor surgery.

    Science.gov (United States)

    Agar, Nathalie Y R; Golby, Alexandra J; Ligon, Keith L; Norton, Isaiah; Mohan, Vandana; Wiseman, Justin M; Tannenbaum, Allen; Jolesz, Ferenc A

    2011-02-01

    Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue. To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents. Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity. Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence. The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of

  20. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    Energy Technology Data Exchange (ETDEWEB)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

    2005-09-01

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for

  1. LiTrack A Fast longitudinal phase space tracking code with graphical user interface

    CERN Document Server

    Emma, Paul

    2005-01-01

    Many linear accelerators, such as linac-based light sources and linear colliders, apply longitudinal phase space manipulations in their design, including electron bunch compression and wakefield-induced energy spread control. Several computer codes handle such issues, but most require detailed information on the transverse focusing lattice. In fact, in most linear accelerators, the transverse distributions do not significantly affect the longitudinal, and can be ignored initially. This allows the use of a fast 2D code to study longitudinal aspects without time-consuming considerations of the transverse focusing. LiTrack is based on a 15-year old code (same name) originally written by one of us (KB), which is now a MATLAB-based code with additional features, such as a graphical user interface and output plotting. The single-bunch tracking includes RF acceleration, bunch compression to 3rd order, geometric and resistive wakefields, aperture limits, synchrotron radiation, and flexible output plotting. The code w...

  2. Summary report of working group 2 on {open_quotes}Beam Production{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Serafini, Luca [INFN and Universita di Milano Via Celoria 16, 20133Milano (Italy)] Cornacchia, Max [SSRL---Stanford Linear Accelerator Center, Stanford, California94309 (United States)

    1997-06-01

    We summarize here the discussions and the communications presented in the working group on {open_quotes}Beam Production{close_quotes}, whose main aim was actually focused on identification of main processes limiting the maximum achievable electron beam brightness at injection into the undulator of a generic linac-based X-Ray single pass FEL. These processes have been divided into three main categories: stochastic effects in the photoelectric emission at the cathode, emittance degradation due to space charge effects in the injector, coherent spontaneous emission in bends ({ital e.g.} magnetic compressors) and its related impact on the emittance and/or peak current budget. {copyright} {ital 1997 American Institute of Physics.}

  3. Ultrafast Science Opportunities with Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    DURR, HERMANN; Wang, X.J., ed.

    2016-04-28

    X-rays and electrons are two of the most fundamental probes of matter. When the Linac Coherent Light Source (LCLS), the world’s first x-ray free electron laser, began operation in 2009, it transformed ultrafast science with the ability to generate laser-like x-ray pulses from the manipulation of relativistic electron beams. This document describes a similar future transformation. In Transmission Electron Microscopy, ultrafast relativistic (MeV energy) electron pulses can achieve unsurpassed spatial and temporal resolution. Ultrafast temporal resolution will be the next frontier in electron microscopy and can ideally complement ultrafast x-ray science done with free electron lasers. This document describes the Grand Challenge science opportunities in chemistry, material science, physics and biology that arise from an MeV ultrafast electron diffraction & microscopy facility, especially when coupled with linac-based intense THz and X-ray pump capabilities.

  4. Hie-Isolde High Beta Cavity Study and Measurements

    CERN Document Server

    D'Elia, A; Pasini, M

    2009-01-01

    The upgrade of the ISOLDE machine at CERN foresees a superconducting linac based on two gap independently phased Nb sputtered Quarter Wave Resonators (QWRs) working at 101.28MHz and producing an accelerating field of 6MV/m on axis. A careful study of the fields in the cavity has been carried out in order to pin down the crucial e-m parameters of the structure such as peak fields, quality factor and e-m power dissipated on the cavity wall. A tuning system with about 200kHz frequency range has been developed in order to cope with fabrication tolerances. In this paper we will report on the cavity simulations. The tuning plate design will be described. Finally the frequency measurements on a cavity prototype at room temperature will be presented.

  5. Reference Physics Design for 1 GeV Injector Linac and Accumulator Ring for Indian Spallation Neutron Source

    CERN Document Server

    Sharma, Amalendu; Patidar, Chirag Bhai; Pal, Mukesh Kumar; Kulkarni, Nita; Goyal, Pradeep Kumar; Jana, Prasanta Kumar; Gaur, Rahul; Prakash, Ram; Dhingra, Rinky; Singh, Urmila; Kumar, Vinit

    2016-01-01

    As a part of the ongoing plan project titled 'R&D activities for high energy proton linac based spallation neutron source', the work on physics design of various subsystems of the injector linac and accumulator ring has been taken up. For the 1 GeV H- injector linac, physics design studies of individual systems have been completed, and the end to end beam dynamics simulation studies have been performed to ensure that the stringent beam dynamics criteria are satisfied for the optimized lattice. Physics design studies to optimize the linear lattice of the accumulator ring have also been completed. The design studies for the beam transport lines from the injector linac to the accumulator ring, and from the accumulator ring to target are currently in progress. This report describes the physics design of various systems of the injector linac and the accumulator ring.

  6. Compact Electron-Linac Design Concept for a Gamma Ray Source

    CERN Document Server

    Chan, K C D; Dale, G; Garnett, R; Kirbie, C; Krawczyk, F L; Russell, S J; Wangler, T P

    2004-01-01

    Gamma-ray sources, particularly sources that are easily transportable, are in high demand for different homeland security applications. We have carried out a review of commercially available electron-linac-based sources, and have investigated alternative compact electron-linac systems that use updated technologies compared with sources that are available commercially. As the results, we propose to develop a new source using an electron linac operating at 17 GHz. It uses a klystron, instead of a magnetron, and a IGBT-switched HV power supply. The source design takes advantages of the advances in X-band linac technology and solid-state HV technology. The higher frequency and upgraded technologies offer smaller size, lighter weight, better efficiency, easier operation, and higher reliability, compared with commercially-available linacs. In this paper, we will describe the source design and our choice of technologies.

  7. A high-compression electron gun for C6+ production: concept, simulations and mechanical design

    Science.gov (United States)

    Mertzig, Robert; Breitenfeldt, M.; Mathot, S.; Pitters, J.; Shornikov, A.; Wenander, F.

    2017-07-01

    In this paper we report on simulations and the mechanical design of a high-compression electron gun for an Electron Beam Ion Source (EBIS) dedicated for production of high intensity and high repetition rate pulses of bare carbon ions for injection into linac-based hadron therapy facilities. The gun is presently under construction at CERN to be retrofitted into the TwinEBIS test bench for experimental studies. We describe the design constraints, show results of numeric simulations and report on the mechanical design featuring several novel ideas. The reported design makes use of combined-function units with reduced number of mechanical joints that were carefully controlled and tuned during the manufacturing phase. The simulations addressed a wide range of topics including the influence of thermal effects, focusing optics, symmetry-breaking misalignments and injection into a full 5 T field.

  8. TOF Spectroscopy measurement with waveform Digitizer at TMSR Photoneutron Source

    CERN Document Server

    Liu, Longxiang; Ma, Yugang; Cao, Xiguang; Cai, Xiangzhou; Chen, Jingen; Zhang, Guilin; Han, Jianlong; Zhang, Guogiang; Hu, Jifeng; Wang, Xiaohe

    2015-01-01

    The Photo-Neutron Source(PNS,phase 1), is an electron linear accelerator (linac) based pulsed neutron facility, combined with TOF technique, was constructed for nuclear data measurement of Thorium Molten Salt Reactor(TMSR) in Shanghai Institute of Applied Physics(SINAP) at JiaDing campus. The TOF detector signal, with the arrive time, pulse shape and pulse hight information, was recorded by a waveform digitizer. Through the pulse-shape discrimination(PSD) between neutrons and gamma-rays and time of Gamma Flash and Neutron signal analyse, the neutron TOF spectrum was deduced with this simple electronics design, and a new DAQ system based on waveform digitizer was used in this test experiment.

  9. High-gradient high-duty-factor Rf photo-cathode electron gun

    Science.gov (United States)

    Rimmer, R. A.; Hartman, N.; Lidia, S. M.; Wang, S.

    2002-05-01

    We describe the analysis and preliminary design of a high-gradient, high-duty factor RF photocathode gun. The gun is designed to operate at high repetition rate or CW, with high gradient on the cathode surface to minimize emittance growth due to space charge forces at high bunch charge. The gun may also be operated in a solenoidal magnetic field for emittance compensation. The design is intended for use in short-pulse, high-charge, and high-repetition rate applications such as linac based X-ray sources. We present and compare the results of gun simulations using different codes, as well as RF and thermal analysis of the structure.

  10. Pulsed Photofission Delayed Gamma Ray Detection for Nuclear Material Identification

    Energy Technology Data Exchange (ETDEWEB)

    John Kavouras; Xianfei Wen; Daren R. Norman; Dante R. Nakazawa; Haori Yang

    2012-11-01

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. High-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. After photofission reactions, delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the fission signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. Isotopic composition measurement methods based on delayed gamma ray spectroscopy will be the primary focus of this work.

  11. Late bilateral temporal lobe necrosis after conventional radiotherapy. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, Michio; Hayashi, Toshiyuki; Kagami, Hiroshi; Murase, Ikurou; Nakatsukasa, Masashi [Saiseikai Utsunomiya Hospital (Japan)

    2003-04-01

    A 63-year-old woman presented with radionecrosis in the bilateral temporal lobes manifesting as dementia about 30 years after undergoing conventional radiotherapy for pituitary adenoma. Computed tomography and magnetic resonance (MR) imaging showed edema and cystic lesions in both temporal lobes. The mass in the left temporal lobe was excised. MR imaging 12 days after surgery showed reduced edema. Her dementia had improved. Radionecrosis usually occurs between several months and a few years after radiotherapy. The incidence of radionecrosis is estimated as 5%, but may be higher with longer follow-up periods. Clinical reports have suggested that larger total doses of radiation are associated with earlier onset of delayed necrosis and the fractional dose is the most significant factor causing cerebral radionecrosis. Radionecrosis can occur long after conventional radiotherapy or stereotactic radiosurgery using a linac-based system or a gamma knife unit. (author)

  12. Compact x-ray lasers in the laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Barletta, W.A.

    1988-10-03

    Compact x-ray lasers in the laboratory can be produced with ultrahigh gradient rf linacs based on recent advances in linac technology by an SLAC-LLNL-LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft x rays in the range of 2--10 nm by passage through short period, high field strength wigglers. Alternatively, the beam can pump a low density dielectric to produce x rays via recombination. Such linear light sources can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 15 refs., 7 figs., 3 tabs.

  13. Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

    Science.gov (United States)

    Yahya, S; Heyes, G; Nightingale, P; Lamin, S; Chavda, S; Geh, I; Spooner, D; Cruickshank, G; Sanghera, P

    2017-04-01

    Arteriovenous malformations (AVMs) are the leading causing of intra-cerebral haemorrhage. Stereotactic radiosurgery (SRS) is an established treatment for arteriovenous malformations (AVM) and commonly delivered using Gamma Knife within dedicated radiosurgery units. Linear accelerator (LINAC) SRS is increasingly available however debate remains over whether it offers an equivalent outcome. The aim of this project is to evaluate the outcomes using LINAC SRS for AVMs used within a UK neurosciences unit and review the literature to aid decision making across various SRS platforms. Results have shown comparability across platforms and strongly supports that an adapted LINAC based SRS facility within a dynamic regional neuro-oncology department delivers similar outcomes (in terms of obliteration and toxicity) to any other dedicated radio-surgical platform. Locally available facilities can facilitate discussion between options however throughput will inevitably be lower than centrally based dedicated national radiosurgery units.

  14. Steady-state thermal studies on the HIE-ISOLDE high-$\\beta$ superconducting cavities

    CERN Document Server

    Alberty, L

    2013-01-01

    The activity of the High Intensity and Energy ISOLDE (HIE-ISOLDE) project aims to construct a superconducting linac based on 101.28 MHz niobium sputtered Quarter Wave Resonators (QWRs). For this, several prototypes of superconducting cavities are currently being developed at CERN using OFE copper as substrate material for Niobium film coating. Two main concepts are currently under development: one consists of rolled, machined, deepdrawed and welded parts; the other is based on machined parts which are put together using electron beam welding. This study presents the results of simulations carried out in order to assess the thermal performance of different designs. The interest for such analysis was raised up before launching the manufacture of the first industrial series, since both rolled and bulk approaches seemed possible.

  15. Diagnostics and Instrumentation for FEL

    CERN Document Server

    Couprie, M E

    2001-01-01

    Free Electron Laser are coherent sources of radiation based on the interaction of a relativistic electron beam in an undulator field. According to the energy of the accelerator, they presently cover a wide spectral range, from the infra-red to the VUV. FELs combine the diagnostics of typical laser systems (for the measurement of spectral and temporal characteristics, the transverse mode pattern, the polarisation) and the diagnostics of relativistic electron beams. The electron beam is characterised in order to evaluate and control the FEL performances, but also in order to measure the effect of the FEL on the electron beam. The FEL characteristics are monitored with various types of detectors, depending mainly on the spectral range. Diagnostics for Linac based Infra Red FELs and storage ring FELs in the UV-VUV will be described. Particular instrumentation, required for FEL operation, such as the optical resonator, possible diagnostics inside the undulator will also be analysed.

  16. Liquid sample delivery techniques for serial femtosecond crystallography.

    Science.gov (United States)

    Weierstall, Uwe

    2014-07-17

    X-ray free-electron lasers overcome the problem of radiation damage in protein crystallography and allow structure determination from micro- and nanocrystals at room temperature. To ensure that consecutive X-ray pulses do not probe previously exposed crystals, the sample needs to be replaced with the X-ray repetition rate, which ranges from 120 Hz at warm linac-based free-electron lasers to 1 MHz at superconducting linacs. Liquid injectors are therefore an essential part of a serial femtosecond crystallography experiment at an X-ray free-electron laser. Here, we compare different techniques of injecting microcrystals in solution into the pulsed X-ray beam in vacuum. Sample waste due to mismatch of the liquid flow rate to the X-ray repetition rate can be addressed through various techniques.

  17. An injector for the proposed Berkeley Ultrafast X-Ray Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Lidia, Steven; Corlett, John; Pusina, Jan; Staples, John; Zholents, Alexander

    2003-05-19

    Berkeley Lab has proposed to build a recirculating linac based X-ray source for ultra-fast dynamic studies [1]. This machine requires a flat electron beam with a small vertical emittance and large x/y emittance ratio to allow for compression of spontaneous undulator emission of soft and hard x-ray pulses, and a low-emittance, round electron beam for coherent emission of soft x-rays via the FEL process based on cascaded harmonic generation [2]. We propose an injector system consisting of two high gradient high repetition rate photo cathode guns [3] (one for each application), an {approx}120 MeV super conducting linear accelerator, a 3rd harmonic cavity for linearization of the longitudinal phase space, and a bunch compressor. We present details of the design and the results of particle tracking studies using several computer codes.

  18. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a (60)Co Magnetic Resonance Image Guidance Radiation Therapy System

    DEFF Research Database (Denmark)

    Wooten, H Omar; Green, Olga; Yang, Min

    2015-01-01

    % prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range doses >20 Gy. The mean doses for all (60)Co plan OARs were within......PURPOSE: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. METHODS AND MATERIALS...... plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses...

  19. MIXI: Mobile Intelligent X-Ray Inspection System

    Science.gov (United States)

    Arodzero, Anatoli; Boucher, Salime; Kutsaev, Sergey V.; Ziskin, Vitaliy

    2017-07-01

    A novel, low-dose Mobile Intelligent X-ray Inspection (MIXI) concept is being developed at RadiaBeam Technologies. The MIXI concept relies on a linac-based, adaptive, ramped energy source of short X-ray packets of pulses, a new type of fast X-ray detector, rapid processing of detector signals for intelligent control of the linac, and advanced radiography image processing. The key parameters for this system include: better than 3 mm line pair resolution; penetration greater than 320 mm of steel equivalent; scan speed with 100% image sampling rate of up to 15 km/h; and material discrimination over a range of thicknesses up to 200 mm of steel equivalent. Its minimal radiation dose, size and weight allow MIXI to be placed on a lightweight truck chassis.

  20. Practical implications for the quality assurance of modulated radiation therapy techniques using point detector arrays.

    Science.gov (United States)

    Kantz, Steffi; Troeller McDermott, Almut; Söhn, Matthias; Reinhardt, Sabine; Belka, Claus; Parodi, Katia; Reiner, Michael

    2017-08-30

    Linac parameters potentially influencing the delivery quality of IMRT and VMAT plans are investigated with respect to threshold ranges, consequently to be considered in a linac based quality assurance procedure. Three commercially available 2D arrays are used to further investigate the influence of the measurement device. Using three commercially available 2D arrays (Mx: MatriXX(evolution) , Oc: Octavius(1500) , Mc: MapCHECK2), simple static measurements, measurements for MLC characterization and dynamic interplay of gantry movement, MLC movement and variable dose rate were performed. The results were evaluated with respect to each single array as well as among each other. Simple static measurements showed different array responses to dose, dose rate and profile homogeneity and revealed instabilities in dose delivery and profile shape during linac ramp up. Using the sweeping gap test, all arrays were able to detect small leaf misalignments down to ±0.1 mm, but this test also demonstrated up to 15% dose deviation due to profile instabilities and fast accelerating leaves during linac ramp up. Tests including gantry rotation showed different stability of gantry mounts for each array. Including gantry movement and dose rate variability, differences compared to static delivery were smaller compared to dose differences when simultaneously controling interplay of gantry movement, leaf movement and dose rate variability. Linac based QA is feasible with the tested commercially available 2D arrays. Limitations of each array and the linac ramp up characteristics should be carefully considered during individual plan generation and regularly checked in linac QA. Especially the dose and dose profile during linac ramp up should be checked regularly, as well as MLC positioning accuracy using a sweeping gap test. Additionally, dynamic interplay tests including various gantry rotation speeds and angles, various leaf speeds and various dose rates should be included. © 2017 The

  1. Ultrafast X-ray Science at the Sub-Picosecond Pulse Source

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Kelly J.; /SLAC, SSRL

    2005-09-30

    The ultrafast, high brightness x-ray free electron laser (XFEL) sources of the future have the potential to revolutionize the study of time dependent phenomena in the natural sciences. These linear accelerator (linac) sources will generate femtosecond (fs) x-ray pulses with peak flux comparable to conventional lasers, and far exceeding all other x-ray sources. The Stanford Linear Accelerator Center (SLAC) has pioneered the development of linac science and technology for decades, and since 2000 SLAC and the Stanford Synchrotron Radiation Laboratory (SSRL) have focused on the development of linac based ultrafast electron and x-ray sources. This development effort has led to the creation of a new x-ray source, called the Sub-Picosecond Pulse Source (SPPS), which became operational in 2003 [1]. The SPPS represents the first step toward the world's first hard x-ray free electron laser (XFEL), the Linac Coherent Light Source (LCLS), due to begin operation at SLAC in 2009. The SPPS relies on the same linac-based acceleration and electron bunch compression schemes that will be used at the LCLS to generate ultrashort, ultrahigh peak brightness electron bunches [2]. This involves creating an energy chirp on the electron bunch during acceleration and subsequent compression of the bunch in a series of energy-dispersive magnetic chicanes to create 80 fs electron pulses. The SPPS has provided an excellent opportunity to demonstrate the viability of these electron bunch compression schemes and to pursue goals relevant to the utilization and validation of XFEL light sources.

  2. Hyperthermically induced changes in high spectral and spatial resolution MR images of tumor tissue – a pilot study

    OpenAIRE

    Foxley, Sean; Fan, Xiaobing; River, Jonathan; Zamora, Marta; Markiewicz, Erica; Sokka, Shunmugavelu; Karczmar, Gregory S.

    2012-01-01

    This pilot study investigated the feasibility of using MRI based on BOLD (blood oxygen level dependent) contrast to detect physiological effects of locally induced hyperthermia in a rodent tumor model. Nude mice bearing AT6.1 rodent prostate tumors inoculated in the hind leg were imaged at 9.4T scanner using a multi-gradient echo pulse sequence to acquire high spectral and spatial resolution (HiSS) data. Approximately 6 °C increases were produced locally in tumor tissue using fiber optic guid...

  3. Exact and variational solutions of 3D eigenmodes in high gain FELs [Exact and variational solutions of 3D eigenmodes in high gain free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2000-05-18

    Exact solution and variational approximation of eigenmodes in high gain FELs are presented. These eigenmodes specify transverse profiles and exponential growth rates of the laser field before saturation. They are self-consistent solutions of coupled Maxwell–Vlasov equations describing FEL interaction taking into account the effects due to energy spread, emittance and betatron oscillations of the electron beam, as well as diffraction and optical guiding of the laser field. A new formalism of scaling is introduced and based on which solutions in various limiting cases are discussed. Additionally, a fitting formula is obtained from interpolating the variational solution for quick calculation of exponential growth rate of the fundamental mode.

  4. TOPS optical correlation program

    Science.gov (United States)

    Lindell, Scott D.

    1993-09-01

    Martin Marietta is conducting a TOPS optical correlation program in which several algorithms and four optical correlators involving two spatial light modulator technologies will be developed and tested. The program will culminate in 1994 with an automatic target recognition flight demonstration using a UH-1 helicopter flying a Fiber Optic Guide Missile (FOG-M) mission profile. The flight demonstration will be conducted by US Army Missile Command (MICOM) and Martin Marietta and will involve detecting, locating and tracking a M60A2 tank positioned among an array of five vehicle types. Current status of the TOPS program will be given.

  5. Guided wave photonics fundamentals and applications with Matlab

    CERN Document Server

    Binh, Le Nguyen

    2012-01-01

    IntroductionHistorical Overview of Integrated Optics and PhotonicsWhy Analysis of Optical Guided-wave Devices?Principal ObjectivesChapters OverviewSingle Mode Planar Optical WaveguidesFormation of Planar Single Mode Waveguide ProblemsApproximate Analytical Methods of SolutionAPPENDIX A: Maxwell Equations in Dielectric MediaAPPENDIX B: Exact Analysis of Clad-linear Optical WaveguidesAPPENDIX C: Wentzel-Kramers-Brilluoin Method, Turning Points and Connection FormulaeAPPENDIX D: Design and Simulation of Planar Optical Waveguides3D Integrated Optical WaveguidesMarcatili's Method| Effective Index M

  6. ALOHA/CHARA at 1.55 μm: sensitivity improvement and on-sky ability to detect astronomical sources in H band

    Science.gov (United States)

    Darré, P.; Grossard, L.; Delage, L.; Reynaud, F.; Scott, N. J.; Sturmann, J.; Ten Brummelaar, T. A.

    2016-07-01

    The interferometric concept named ALOHA (Astronomical Light Optical Hybrid Analysis) offers an alternative for high resolution imaging in the mid-infrared domain by shifting the astronomical light to shorter wavelength where optical guided components from telecommunications are available and efficient. A prototype with two arms converting a signal from 1.55 μm to 630 nm is used to validate the concept in laboratory and on-sky. Thanks to collaboration with the CHARA team, photometric tests were achieved with a single arm of the interferometer and have allowed to predict instrument performance in its interferometric configuration in order to obtain first fringes in H band.

  7. Intraoperative computed tomography with integrated navigation system in a multidisciplinary operating suite.

    Science.gov (United States)

    Uhl, Eberhard; Zausinger, Stefan; Morhard, Dominik; Heigl, Thomas; Scheder, Benjamin; Rachinger, Walter; Schichor, Christian; Tonn, Jörg-Christian

    2009-05-01

    We report our preliminary experience in a prospective series of patients with regard to feasibility, work flow, and image quality using a multislice computed tomographic (CT) scanner combined with a frameless neuronavigation system (NNS). A sliding gantry 40-slice CT scanner was installed in a preexisting operating room. The scanner was connected to a frameless infrared-based NNS. Image data was transferred directly from the scanner into the navigation system. This allowed updating of the NNS during surgery by automated image registration based on the position of the gantry. Intraoperative CT angiography was possible. The patient was positioned on a radiolucent operating table that fits within the bore of the gantry. During image acquisition, the gantry moved over the patient. This table allowed all positions and movements like any normal operating table without compromising the positioning of the patient. For cranial surgery, a carbon-made radiolucent head clamp was fixed to the table. Experience with the first 230 patients confirms the feasibility of intraoperative CT scanning (136 patients with intracranial pathology, 94 patients with spinal lesions). After a specific work flow, interruption of surgery for intraoperative scanning can be limited to 10 to 15 minutes in cranial surgery and to 9 minutes in spinal surgery. Intraoperative imaging changed the course of surgery in 16 of the 230 cases either because control CT scans showed suboptimal screw position (17 of 307 screws, with 9 in 7 patients requiring correction) or that tumor resection was insufficient (9 cases). Intraoperative CT angiography has been performed in 7 cases so far with good image quality to determine residual flow in an aneurysm. Image quality was excellent in spinal and cranial base surgery. The system can be installed in a preexisting operating environment without the need for special surgical instruments. It increases the safety of the patient and the surgeon without necessitating a change

  8. Optical diagnostics for laser wakefields in plasma channels

    Science.gov (United States)

    Gaul, E. W.; Le Blanc, S. P.; Downer, M. C.

    1998-11-01

    Laser wakefield accelerators can excite large amplitude electrostatic fields (E >= 100 GV/m) which are potentially suitable for compact accelerators and advanced high energy colliders. An accurate diagnostic tool is necessary to test the physical effects in the wakefield predicted by theory and numerical simulations, and to have control over experiments. Frequency domain interferometry (FDI) (C. W. Siders et. al.), Phys. Rev. Lett. 76, 3570 (1995) has been developed in previous work. We experimentally demonstrate single-shot FDI as a sensitive diagnostic technique for probing laser wakefields. To generate wakefields longer than the diffraction limit, optical guiding of the laser pulse is necessary. An optical guide is formed by the hydrodynamic expansion of a cylindrical shock wave driven by a laser heated plasma, which is generated by laser pulse focused with an axicon lens (C. G. Durfee and H. M. Milchberg, Phys. Rev. Lett. 71, 2409 (1993)) to intensities of ~= 10^13 W/cm^2. These are too low to reach multi-photon ionization or significant collisional ionization in <= 1 atm helium. We preionize Helium gas with an electrical discharge for efficient inverse bremsstrahlung absorption of the laser pulse and formation of a plasma channel. Spatially resolved chirped pulse interferometry is used to measure the radial electron density profile of the channel.

  9. POGAL B-Axis Motor Test

    Energy Technology Data Exchange (ETDEWEB)

    Hale, L C; Wulff, T A

    2004-06-28

    The Aerotech model S-180-69-A, a brushless DC motor of slotless design, was selected as the B-axis drive for the Precision Optical Grinder and Lathe (POGAL). It is common knowledge that a slotless motor will have effectively no magnetic cogging and much less torque ripple than a traditional slot-type motor. It is logical to believe that the radial and axial forces generated between the rotor and stator would also be smaller for a slotless design. This is important when a frameless motor is directly coupled to the axis, as these forces directly influence the axis and affect its error motion. It is the purpose of this test to determine the radial and axial forces generated by the Aerotech motor and to estimate their effect on the error motion of the axis using a mathematical model of the hydrostatic bearing being designed for POGAL. The test results combined with a mathematical model of the POGAL B axis indicate that the directly coupled Aerotech motor will be quite acceptable. In the radial direction, the residual motor force, after subtracting out the one-cycle force, could cause sub nanometer level error motion at the tool point. The axial direction is not in a sensitive direction for turning.

  10. Clinical results of a pilot study on stereovision-guided stereotactic radiotherapy and intensity modulated radiotherapy.

    Science.gov (United States)

    Li, Shidong; Kleinberg, Lawrence R; Rigamonti, Daniele; Wharam, Moody D; Rashid, Abdul; Jackson, Juan; Djajaputra, David; He, Shenjen; Creasey, Tunisia; DeWeese, Theodore L

    2010-12-01

    Real-time stereovision-guidance has been introduced for efficient and convenient fractionated stereotactic radiotherapy (FSR) and image-guided intensity-modulated radiation therapy (IMRT). This first pilot study is to clinically evaluate its accuracy and precision as well as impact on treatment doses. Sixty-one FSR patients wearing stereotactic masks (SMs) and nine IMRT patients wearing flexible masks (FMs), were accrued. Daily target reposition was initially based-on biplane-radiographs and then adjusted in six degrees of freedom under real-time stereovision guidance. Mean and standard deviation of the head displacements measured the accuracy and precision. Head positions during beam-on times were measured with real-time stereovisions and used for determination of delivered doses. Accuracy ± ± precision in direction with the largest errors shows improvement from 0.4 ± 2.3 mm to 0.0 ± 1.0 mm in the inferior-to-superior direction for patients wearing SM or from 0.8 ± 4.3 mm to 0.4 ± 1.7 mm in the posterior-to-anterior direction for patients wearing FM. The image-guidance increases target volume coverage by >30% for small lesions. Over half of head position errors could be removed from the stereovision-guidance. Importantly, the technique allows us to check head position during beam-on time and makes it possible for having frameless head refixation without tight masks.

  11. Evaluation of Setup Uncertainties for Single-Fraction SRS by Comparing the Two Different Mask-Creation Methods

    CERN Document Server

    Baek, Jong Geun; Oh, Young Kee; Lee, Hyun Jeong; Kim, Eng Chan

    2015-01-01

    The purpose of this study was to evaluate the setup uncertainties for single-fraction stereotactic radiosurgery (SF-SRS) based on the clinical data with the two different mask-creation methods using pretreatment CBCT imaging guidance. Dedicated frameless fixation BrainLAB masks for 23 patients were created as a routine mask (R-mask) making method, as explained in the BrainLAB user manual. The alternative masks (A-mask) which were created by modifying the cover range of the R-mask for the patient head were used for 23 patients. The systematic errors including the each mask and stereotactic target localizer were analyzed and the errors were calculated as the mean and standard deviation (SD) from the LR, SI, AP, and yaw setup corrections. In addition, the frequency of three-dimensional (3D) vector length were also analyzed. The values of the mean setup corrections for the R-mask in all directions were small; < 0.7 mm and < 0.1 degree, whereas the magnitudes of the SDs were relatively large compared to the ...

  12. Technological Advances in Deep Brain Stimulation.

    Science.gov (United States)

    Ughratdar, Ismail; Samuel, Michael; Ashkan, Keyoumars

    2015-01-01

    Functional and stereotactic neurosurgery has always been regarded as a subspecialty based on and driven by technological advances. However until recently, the fundamentals of deep brain stimulation (DBS) hardware and software design had largely remained stagnant since its inception almost three decades ago. Recent improved understanding of disease processes in movement disorders as well clinician and patient demands has resulted in new avenues of development for DBS technology. This review describes new advances both related to hardware and software for neuromodulation. New electrode designs with segmented contacts now enable sophisticated shaping and sculpting of the field of stimulation, potentially allowing multi-target stimulation and avoidance of side effects. To avoid lengthy programming sessions utilising multiple lead contacts, new user-friendly software allows for computational modelling and individualised directed programming. Therapy delivery is being improved with the next generation of smaller profile, longer-lasting, re-chargeable implantable pulse generators (IPGs). These include IPGs capable of delivering constant current stimulation or personalised closed-loop adaptive stimulation. Post-implantation Magnetic Resonance Imaging (MRI) has long been an issue which has been partially overcome with 'MRI conditional devices' and has enabled verification of DBS lead location. Surgical technique is considering a shift from frame-based to frameless stereotaxy or greater role for robot assisted implantation. The challenge for these contemporary techniques however, will be in demonstrating equivalent safety and accuracy to conventional methods. We also discuss potential future direction utilising wireless technology allowing for miniaturisation of hardware.

  13. Stereotaxy, navigation and the temporal concatenation.

    Science.gov (United States)

    Apuzzo, M L; Chen, J C

    1999-01-01

    Nautical and cerebral navigation share similar elements of functional need and similar developmental pathways. The need for orientation necessitates the development of appropriate concepts, and such concepts are dependent on technology for practical realization. Occasionally, a concept precedes technology in time and requires periods of delay for appropriate development. A temporal concatenation exists where time allows the additive as need, concept and technology ultimately provide an endpoint of elegant solution. Nautical navigation has proceeded through periods of dead reckoning and celestial navigation to satellite orientation with associated refinements of instrumentation and charts for guidance. Cerebral navigation has progressed from craniometric orientation and burr hole mounted guidance systems to simple rectolinear and arc-centered devices based on radiographs to guidance by complex anatomical and functional maps provided as an amalgam of modern imaging modes. These maps are now augmented by complex frame and frameless systems which allow not only precise orientation, but also point and volumetric action. These complex technical modalities required and developed in part from elements of maritime navigation that have been translated to cerebral navigation in a temporal concatenation.

  14. Refining the Indications for the Addition of Orbital Osteotomy during Anterior Cranial Base Approaches: Morphometric and Radiologic Study of the Anterior Cranial Base Osteology.

    Science.gov (United States)

    DeBattista, Juan Carlos; Andaluz, Norberto; Zuccarello, Mario; Kerr, Robert G; Keller, Jeffrey T

    2014-08-01

    Objectives In anatomic and radiologic morphometric studies, we examine a predictive method, based on preoperative imaging of the anterior cranial base, to define when addition of orbital osteotomy is warranted. Design Anatomic and radiographic study. Setting In 100 dry skulls, measurements in the anterior cranial fossa included three lines and two angles based on computerized tomography (CT) scans taken in situ and validated using frameless stereotactic navigation. The medial angle (coronal plane) was the intersection between the highest point of both orbits and the midpoint between the two frontoethmoidal sutures to each orbital roof high point. The oblique angle (sagittal plane) was the intersection at the midpoint of the limbus sphenoidale. Results No identifiable morphometric patterns were found for our classification of anterior fossae; the two-tailed distribution pattern was similar for all skulls, disproving the hypothetical correlation between visual appearance and morphometry. Orbital heights (range: 6.6-18.7 mm) showed a linear relationship with medial and oblique angles, and they had a linear distribution relative to angular increments. Orbital heights > 11 mm were associated with angles ≥ 20 degrees and more likely to benefit from orbitotomy. Conclusion Preoperative CT measurement of orbital height appears feasible for predicting when orbitotomy is needed, and it warrants further testing.

  15. Performance Comparison of Stion CIGS Modules to Baseline Monocrystalline Modules at the New Mexico Florida and Vermont Regional Test Centers: January 2015-December 2016.

    Energy Technology Data Exchange (ETDEWEB)

    Lave, Matthew Samuel [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Stein, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Burnham, Laurie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-01

    This report provides performance data and analysis for two Stion copper indium gallium selenide (CIGS) module types, one framed, the other frameless, and installed at the New Mexico, Florida and Vermont RTCs. Sandia looked at data from both module types and compared the latter with data from an adjacent monocrystalline baseline array at each RTC. The results indicate that the Stion modules are slightly outperforming their rated power, with efficiency values above 100% of rated power, at 25degC cell temperatures. In addition, Sandia sees no significant performance differences between module types, which is expected because the modules differ only in their framing. In contrast to the baseline systems, the Stion strings showed increasing efficiency with increasing irradiance, with the greatest increase between zero and 400 Wm -2 but still noticeable increases at 1000 Wm -2 . Although baseline data availability in Vermont was spotty and therefore comparative trends are difficult to discern, the Stion modules there may offer snow- shedding advantages over monocrystalline-silicon modules but these findings are preliminary.

  16. System precision assessment ExacTrac 6D® BrainLab of the Hospital das Clinicas da Faculdade de Medicina da USP; Avaliacao da precisao do sistema Exactrac 6D® BrainLab do Hospital das Clinicas da Faculdade de Medicina da USP

    Energy Technology Data Exchange (ETDEWEB)

    Maistro, Carlos E.B., E-mail: carloseduardo.bravinmaistro@gmail.com [Programa de Residencia Multiprofissional em Fisica Medica, Faculdade de Medicina de Sao Paulo, SP (Brazil); Nakandakari, Marcos V.N.; Ribeiro, Victor A.B.; Sales, Camila P. de; Rodrigues, Laura N. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Radiologia. Servico de Radioterapia. Hospital das Clinicas

    2015-08-15

    The goal of this study was to evaluate the precision of ExacTrac 6D® Brainlab system, installed at Hospital das Clinicas da Faculdade de Medicina da USP, in frameless radiosurgery treatments. Four sets of tests were performed for different purposes in order to assess the following parameters: the accuracy of location through infrared system; evaluation of the reproducibility of fusion algorithm; evaluation of the X-ray system; and the end-to-end test with the goal of assess the overall accuracy of the system. It was found that the infrared system showed a maximum deviation of 0.5 mm in terms of positioning and the X-ray system showed a precision of 0.15 mm and 0.6°. The reproducibility of fusion algorithms provided a maximum deviation in position which was less than 0.5 mm and 0.5° and the quantitative analysis of the results for end-to-end test showed an overall accuracy of the system better than 0.8 mm. (author)

  17. Miniature Bose-Einstein condensate system design based on a transparent atom chip

    Science.gov (United States)

    Cheng, Jun; Li, Xiaolin; Zhang, Jingfang; Xu, Xinping; Jiang, Xiaojun; Zhang, Haichao; Wang, Yuzhu

    2016-08-01

    We propose a new miniature Bose-Einstein condensate (BEC) system based on a transparent atom chip with a compact external coil structure. A standard six-beam macroscopic magneto-optical trap (MOT) is able to be created near the chip surface due to the chip’s transparency. A novel wire pattern consisting of a double-z wire and a z-shaped wire is designed on the transparent atom chip. With a vertical bias magnetic field, the double-z wire can create the quadrupole magnetic field of an intermediate chip MOT, which is suitable for transporting atoms from the macroscopic MOT to the chip z-wire trap efficiently. The compact external coil structure is designed with a rectangular frameless geometry consisting of only four coil pairs and its volume is less than 0.3 liters. The maximum system power consumption during the BEC generation procedure is about 45 W. The miniature system is evaluated, and about 3 × 106 atoms can be loaded into the chip z-wire trap. The miniature chip BEC system has the advantages of small volume and low power consumption, and it has great potential for practical applications of BEC.

  18. Clinical efficacy and safety of surface imaging guided radiosurgery (SIG-RS) in the treatment of benign skull base tumors.

    Science.gov (United States)

    Lau, Steven K M; Patel, Kunal; Kim, Teddy; Knipprath, Erik; Kim, Gwe-Ya; Cerviño, Laura I; Lawson, Joshua D; Murphy, Kevin T; Sanghvi, Parag; Carter, Bob S; Chen, Clark C

    2017-04-01

    Frameless, surface imaging guided radiosurgery (SIG-RS) is a novel platform for stereotactic radiosurgery (SRS) wherein patient positioning is monitored in real-time through infra-red camera tracking of facial topography. Here we describe our initial clinical experience with SIG-RS for the treatment of benign neoplasms of the skull base. We identified 48 patients with benign skull base tumors consecutively treated with SIG-RS at a single institution between 2009 and 2011. Patients were diagnosed with meningioma (n = 22), vestibular schwannoma (n = 20), or nonfunctional pituitary adenoma (n = 6). Local control and treatment-related toxicity were retrospectively assessed. Median follow-up was 65 months (range 61-72 months). Prescription doses were 12-13 Gy in a single fraction (n = 18), 8 Gy × 3 fractions (n = 6), and 5 Gy × 5 fractions (n = 24). Actuarial tumor control rate at 5 years was 98%. No grade ≥3 treatment-related toxicity was observed. Grade ≤2 toxicity was associated with symptomatic lesions (p = 0.049) and single fraction treatment (p = 0.005). SIG-RS for benign skull base tumors produces clinical outcomes comparable to conventional frame-based SRS techniques while enhancing patient comfort.

  19. Advanced polymer PV system: PVMaT 4A1 annual report, September 1995--September 1996

    Energy Technology Data Exchange (ETDEWEB)

    Hanoka, J; Chleboski, R; Farber, M; Fava, J; Kane, P; Martz, J [Evergreen Solar, Inc., Waltham, MA (United States)

    1997-06-01

    Purpose of this subcontract was to produce lower module and systems costs through the innovative use of polymeric materials. The Innovative Mounting System (IMS) was developed and testing begun during the first year of this contract. IMS reduces the cost of installed PV systems by reducing labor and materials costs both in the factory and in field installation. It incorporates several advances in polymers, processing methods and product design. An advanced backskin material permits elimination of the conventional Al perimeter frame by protecting and sealing the edge and by direct bonding of multifunctional mounting bars. Electrical interconnection is easier and more reliable with a new junction box. Feasibility of a non-vacuum, high-throughput lamination method was also demonstrated, involving a novel transparent encapsulant with UV stabilization package that can be laminated in air and which should lead to longer field life than conventional designs. The first-year program culminated in the fielding of prototype products with the new encapsulant, backskin, junction box, frameless edge seal, and IMS. Feedback and marketing information from potential customers were solicited. Result promises a $0.50/watt manufacturing and system cost reductions as well as increased system lifetime. The second year will complete refinement and test of the encapsulant and backskin, complete the new lamination method, and refine product designs.

  20. Daily-diary Evaluated Side Effects of Dose-escalation Radiotherapy of Prostate Cancer Using the Stereotactic Beamcath Technique

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, Per; Bergstroem, Per; Loefroth, Per-Olov; Franzen, Lars; Henriksson, Roger; Widmark, Anders [Umeaa Univ. (Sweden). Dept. of Radiation Sciences

    2003-06-01

    The aim of this study was to evaluate self-assessed late side effects in patients with prostate cancer treated with frameless stereotactic dose-escalation radiotherapy using BeamCath, a new technique that has been developed for accurate positioning of the prostate at treatment set-up, and in which a specially designed urethral catheter containing high-density fiducial markers is used. The method was tested in the first 104 patients in a Scandinavian dose-escalation study with doses up to 76 Gy. Side effects were reported in a daily diary and evaluated at the start of treatment (baseline) and at 1-year follow-up. The patients were compared with those treated with conventional (n=53) and conformal techniques (n=175). Dose-escalation radiotherapy (76 Gy) decreased urinary frequency, urgency and starting problems at 1-year in comparison with baseline. The dose-escalation therapy did not induce any increase in gastrointestinal side effects in comparison with the effect of conformal therapy h70 Gy at the 1-year follow-up, apart from a slight increase in rectal mucus in the 76 Gy group. All groups, except patients receiving the 74 Gy with smaller fields, reported a slight increase in gastrointestinal toxicity at 1-year compared with baseline. Dose-escalation radiotherapy of prostate cancer using the BeamCath technique did not induce any significant increase in late side effects in comparison with conformal technique.

  1. New Technologies for Intrauterine Contraception and Treatment: Design that Fits

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2011-01-01

    Full Text Available A strategic advantage of intrauterine devices and systems is that, unlike the Pill, they are genuinely ‘fit-and-forget’. In use, they are more effective than Pills, particularly in adolescents and nulliparous women, as they have a relatively high continuation of use. The World Health Organization concluded that IUDs can be used and that they are safe for young women, including adolescents. Because adolescents and young nulliparous women contribute disproportionately to the epidemic of unintended pregnancies, suitable long-acting methods of contraception, such as the IUD or IUS, should be advocated as firstline choices for interval, emergency and immediate post-abortal contraception in this population of women. However, a major drawback is that they do not fit in uterine cavities of many women. Uterine cavities of nulliparous women are usually smaller than those of parous women. As current copper IUDs and the, at present, only available LNG-IUS may not be suitable for many young women, new developments in intrauterine technology, smaller frameless and framed copper and hormone-releasing devices, could help increase the prevalence of use, particularly continued use of this method in women, including in adolescents and nulliparous women, and help reduce the number of unintended pregnancies and induced abortions.

  2. A Case of Primary Central Nervous System Lymphoma Located at Brain Stem in a Child

    Science.gov (United States)

    Kim, Jinho

    2016-01-01

    Primary central nervous system lymphoma (PCNSL) is an extranodal Non-Hodgkin's lymphoma that is confined to the brain, eyes, and/or leptomeninges without evidence of a systemic primary tumor. Although the tumor can affect all age groups, it is rare in childhood; thus, its incidence and prognosis in children have not been well defined and the best treatment strategy remains unclear. A nine-year old presented at our department with complaints of diplopia, dizziness, dysarthria, and right side hemiparesis. Magnetic resonance image suggested a diffuse brain stem glioma with infiltration into the right cerebellar peduncle. The patient was surgically treated by craniotomy and frameless stereotactic-guided biopsy, and unexpectedly, the histopathology of the mass was consistent with diffuse large B cell lymphoma, and immunohistochemical staining revealed positivity for CD20 and CD79a. Accordingly, we performed a staging work-up for systemic lymphoma, but no evidence of lymphoma elsewhere in the body was obtained. In addition, she had a negative serologic finding for human immunodeficient virus, which confirmed the histopathological diagnosis of PCNSL. She was treated by radiosurgery at 12 Gy and subsequent adjuvant combination chemotherapy based on high dose methotrexate. Unfortunately, 10 months after the tissue-based diagnosis, she succumbed due to an acute hydrocephalic crisis. PMID:27867930

  3. Interval From Imaging to Treatment Delivery in the Radiation Surgery Age: How Long Is Too Long?

    Energy Technology Data Exchange (ETDEWEB)

    Seymour, Zachary A., E-mail: seymourz@radonc.ucsf.edu [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States); Fogh, Shannon E.; Westcott, Sarah K.; Braunstein, Steve [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States); Larson, David A. [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States); Department of Neurological Surgery, University of California at San Francisco, San Francisco, California (United States); Barani, Igor J.; Nakamura, Jean; Sneed, Penny K. [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California (United States)

    2015-09-01

    Purpose: The purpose of this study was to evaluate workflow and patient outcomes related to frameless stereotactic radiation surgery (SRS) for brain metastases. Methods and Materials: We reviewed all treatment demographics, clinical outcomes, and workflow timing, including time from magnetic resonance imaging (MRI), computed tomography (CT) simulation, insurance authorization, and consultation to the start of SRS for brain metastases. Results: A total of 82 patients with 151 brain metastases treated with SRS were evaluated. The median times from consultation, insurance authorization, CT simulation, and MRI for treatment planning were 15, 7, 6, and 11 days to SRS. Local freedom from progression (LFFP) was lower in metastases with MRI ≥14 days before treatment (P=.0003, log rank). The 6- and 12-month LFFP rate were 95% and 75% for metastasis with interval of <14 days from MRI to treatment compared to 56% and 34% for metastases with MRI ≥14 days before treatment. On multivariate analysis, LFFP remained significantly lower for lesions with MRI ≥14 days at SRS (P=.002, Cox proportional hazards; hazard ratio: 3.4, 95% confidence interval: 1.6-7.3). Conclusions: Delay from MRI to SRS treatment delivery for brain metastases appears to reduce local control. Future studies should monitor the timing from imaging acquisition to treatment delivery. Our experience suggests that the time from MRI to treatment should be <14 days.

  4. Photovoltaic stand-alone modular systems, phase 2

    Science.gov (United States)

    Naff, G. J.; Marshall, N. A.

    1983-01-01

    The final hardware and system qualification phase of a two part stand-alone photovoltaic (PV) system development is covered. The final design incorporated modular, power blocks capable of expanding incrementally from 320 watts to twenty kilowatts (PK). The basic power unit (PU) was nominally rated 1.28 kWp. The controls units, power collection buses and main lugs, electrical protection subsystems, power switching, and load management circuits are housed in a common control enclosure. Photo-voltaic modules are electrically connected in a horizontal daisy-chain method via Amp Solarlok plugs mating with compatible connectors installed on the back side of each photovoltaic module. A pair of channel rails accommodate the mounting of the modules into a frameless panel support structure. Foundations are of a unique planter (tub-like) configuration to allow for world-wide deployment without restriction as to types of soil. One battery string capable of supplying approximately 240 ampere hours nominal of carryover power is specified for each basic power unit. Load prioritization and shedding circuits are included to protect critical loads and selectively shed and defer lower priority or noncritical power demands. The baseline system, operating at approximately 2 1/2 PUs (3.2 kW pk.) was installed and deployed. Qualification was successfully complete in March 1983; since that time, the demonstration system has logged approximately 3000 hours of continuous operation under load without major incident.

  5. Toward integrated image guided liver surgery

    Science.gov (United States)

    Jarnagin, W. R.; Simpson, Amber L.; Miga, M. I.

    2017-03-01

    While clinical neurosurgery has benefited from the advent of frameless image guidance for over three decades, the translation of image guided technologies to abdominal surgery, and more specifically liver resection, has been far more limited. Fundamentally, the workflow, complexity, and presentation have confounded development. With the first real efforts in translation beginning at the turn of the millennia, the work in developing novel augmented technologies to enhance screening, planning, and surgery has come to realization for the field. In this paper, we will review several examples from our own work that demonstrate the impact of image-guided procedure methods in eight clinical studies that speak to: (1) the accuracy in planning for liver resection, (2) enhanced surgical planning with portal vein embolization impact, (3) linking splenic volume changes to post-hepatectomy complications, (4) enhanced intraoperative localization in surgically occult lesions, (5) validation of deformation correction, and a (6) a novel blinded study focused at the value of deformation correction. All six of these studies were achieved in human systems and show the potential impact image guided methodologies could make on liver tissue resection procedures.

  6. Extended abstracts from the eight international meeting on progress in radio-oncology (ICRO/OeGRO 8), Salzburg, May 16-19, 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-12-15

    This part of the journal includes 25 extended abstracts from the Eight International Meeting on Progress in Radio-Oncology ICRO/OeGRO8 in Salzburg, Austria (May 16-19, 2007): adaptive radiotherapy of prostate cancer; homoradiation of prostate cancer; radiation therapy, chemotherapy and combined chemoradiation in the management of malignant glioma; return of high-dose per fraction radiotherapy: paradigm change, lesson from the past; from bench to bedside: enhancing the effects of radiotherapy through biological escalation; gastric cancer: MAGIC or Macdonald; analysis of set-up errors in 70 consecutive patients treated for rectal carcinoma; molecular targeted therapy; teleradiooncology: telematics applications in therapeutic radiology and oncology; in-room guidance technologies for adaptive radiotherapy; dose escalation with photons - emerging technologies; late side-effects after pelvic irradiation; a frameless robotic stereotactic system for highly focused extracranial radiotherapy; altered fractionation in head and neck tumors: an alternative to chemotherapy; integration of molecular targeting with radiotherapy; OGRT pf prostate cancer patients based on CBCT and kV images; hyperfractionation in medulloblastoma; re-irradiation of recurrent prostate cancer; dose reduction of radiotherapy in early-stage testicular semimoma; photons versus protons; randomized clinical trials on postoperative radiotherapy for high-risk head and neck cancer; cardiac risk in multimodal breast cancer treatment; the use of hyperthermia treatment planning in clinical practice; presentation of the ICRU-IAEA Joint Report 'prescribing, recording, and reporting proton-beam therapy'.

  7. A 2D smart pixel detector for time-resolved protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Beuville, E.; Cork, C.; Earnest, T. [and others

    1995-10-01

    A smart pixel detector is being developed for Time Resolved Crystallography for biological and material science applications. Using the Pixel detector presented here, the Laue method will enable the study of the evolution of structural changes that occur within the protein as a function of time. The x-ray pixellated detector is assembled to the integrated circuit through a bump bonding process. Within a pixel size of 150 x 150 {mu}m{sup 2}, a low noise preamplifier-shaper, a discriminator, a 3 bit counter and the readout logic are integrated. The readout, based on the Column Architecture principle, will accept hit rates above 5x10{sup 8}/cm{sup 2}/s with a maximum hit rate per pixel of 1 MHz. This detector will allow time resolved Laue crystallography to be performed in a frameless operation mode, without dead time. Target specifications, architecture, and preliminary results on the 8 x 8 front-end prototype and column readout are presented.

  8. [Neuronavigation in the surgical planning of callosotomy].

    Science.gov (United States)

    Valencia Calderón, Carlos; Castro Cevallos, Alfredo; Calderón Valdiviezo, Ana; Escobar Dávila, Roberto; Parra Rosales, Fausto; Quispe Alcocer, Julio; Vásquez Hahn, Catalina

    2016-01-01

    To describe the usefulness of 3D computer-assisted preoperative neuronavigation for stereoscopic location of the venous sinuses, arterial branches, and corpus callosum, to extrapolate anatomical landmarks on the surgical field and make decisions before the intervention. A prospective analysis was performed on patients with refractory epilepsy who underwent neuronavigation-assisted callosotomy (BRAIN LAB Dual). A total of 10 neuronavigation-assisted callosotomies were performed in the year 2014. The ages of the patients (4 males and 6 females) were between 4 and 13 years (mean 7; SD 3.02). The most common indication for callosotomy in our sample was Lennox Gastoux (5 patients). A right parasagittal craniotomy was performed in 8 patients. An anterior two-thirds callosotomy was performed in 8 patients and anterior three-quarters in 2 patients. The mean accuracy of the neuronavigation procedure was less than 2mm. In no cases were there significant intraoperative surgical complications. Callosotomy using frameless guided neuronavigation is an accurate and safe technique in patients with epilepsy refractory to surgical resection. Copyright © 2015 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  9. STRUCTURAL SOLUTIONS AND SPECIAL FEATURES OF THE THERMAL PROTECTION ANALYSIS OF EXTERIOR WALLS OF BUILDINGS MADE OF AUTOCLAVED GAS-CONCRETE BLOCKS

    Directory of Open Access Journals (Sweden)

    Bedov Anatolij Ivanovich

    2012-10-01

    Full Text Available Relevant structural solutions, physical and mechanical characteristics, coefficients of thermal conductivity for exterior masonry walls made of autoclaved gas-concrete blocks are provided in the article. If a single-layer wall is under consideration, an autoclaved gas-concrete block is capable of performing the two principal functions of a shell structure, including the function of thermal protection and the bearing function. The functions are performed simultaneously. Therefore, the application of the above masonry material means the design development and erection of exterior walls of residential buildings noteworthy for their thermal efficiency. In the event of frameless structures, the height of the residential building in question may be up to 5 stories, while the use of a monolithic or a ready-made frame makes it possible to build high-rise buildings, and the number of stories is not limited in this case. If the average block density is equal to 400…500 kilograms per cubic meter, the designed wall thickness is to be equal to 400 mm. Its thermal resistance may be lower than the one set in the event of the per-element design of the thermal protection (Rreq = 3.41 м2 C/Watt, in Ufa, although it will meet the requirements of the applicable regulations if per-unit power consumption rate is considered.

  10. Environmental life cycle assessment of a large-scale grid-connected PV power plant. Case study Moura 62 MW PV power plant

    Energy Technology Data Exchange (ETDEWEB)

    Suomalainen, Kiti

    2006-01-15

    An environmental life cycle assessment has been conducted for a 62 MW grid-connected photovoltaic installation to study the role of BOS components in the total environmental load. Also the influence of the current electricity supply has been investigated. For an alternative approach a net output approach has been used, where all electricity requirements are supplied by the photovoltaic installation itself. The components taken into account are monocrystalline silicon cells in frameless modules, steel support structures in concrete foundations, inverters, transformers, cables, transports and construction of roads and buildings. For stationary inert products without intrinsic energy requirements, such as cables, inverters, support structures etc., only raw material acquisition and processing are taken into account, since they are considered the most dominant stages in the life cycle. The results confirm a minor environmental load from BOS components compared to the module life cycle, showing approximately ten to twenty percent impact of the total. Uncertainties lie in the approximations for electronic devices as well as in the emissions from silicon processing. Concerning the electricity supply, the results differ considerably depending on which system perspective is used. In the net output approach the impacts decrease with approximately ninety percent from the traditional approach. Some increases are also shown in toxicity categories due to the increased module production needed for the enlargement of the installation.

  11. Radiosurgery in the management of brain metastasis: a retrospective single-center study comparing Gamma Knife and LINAC treatment.

    Science.gov (United States)

    Tuleasca, Constantin; Negretti, Laura; Faouzi, Mohamed; Magaddino, Vera; Gevaert, Thierry; von Elm, Erik; Levivier, Marc

    2017-03-24

    OBJECTIVE The authors present a retrospective analysis of a single-center experience with treatment of brain metastases using Gamma Knife (GK) and linear accelerator (LINAC)-based radiosurgery and compare the results. METHODS From July 2010 to July 2012, 63 patients with brain metastases were treated with radiosurgery. Among them, 28 (with 83 lesions) were treated with a GK unit and 35 (with 47 lesions) with a LINAC. The primary outcome was local progression-free survival (LPFS), evaluated on a per-lesion basis. The secondary outcome was overall survival (OS), evaluated per patient. Statistical analysis included standard tests and Cox regression with shared-frailty models to account for the within-patient correlation. RESULTS The mean follow-up period was 11.7 months (median 7.9 months, range 1.7-32 months) for GK and 18.1 months (median 17 months, range 7.5-28.7 months) for LINAC. The median number of lesions per patient was 2.5 (range 1-9) in the GK group and 1 (range 1-3) in the LINAC group (p 0.05). The mean OS was 16.0 months (95% CI 11.2-20.9 months) in the GK group, compared with 20.9 months (95% CI 16.4-25.3 months) in the LINAC group. Univariate and multivariate analysis showed that a lower graded prognostic assessment (GPA) score, noncontrolled systemic status at last radiological assessment, and older age were associated with lower OS; after adjustment of these covariables by Cox regression, the OS was similar in the 2 groups. CONCLUSIONS In this retrospective study comparing GK and LINAC-based radiosurgery for brain metastases, patients with more severe disease were treated by GK, including those harboring lesions of greater number, of radioresistant type, or in highly functional areas. The risk of local progression for the LINAC group was almost twice that in the GK group, although the difference was not statistically significant. Importantly, the OS rates were similar for the 2 groups, although GK was used in patients with more complex brain

  12. Photon science 2008. Highlights and HASYLAB annual report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The following topics are dealt with: A femtosecond X-ray/optical cross-correlator, ultrafast movies of nanoscale dynamics, massively parallel X-ray holography, clusters in super intense FLASH pulses, a chemical driven insulator-metal transition, tough silk, insight into the reactivity, the many faces of molecular assemblies in electronic devices, cooperative or self-centred electrons, visualizing a lost painting by Vincent van Gogh, metal contaminations in small water fleas, small-angle X-ray scattering as complement of crystallography, mapping the protein world, how metallic iron eats its own native oxide, hard X-ray diffraction imaging, the centre for free-electron laser science CFEL, the Hamburg EMBL unit, the Max-Planck unit for structural molecular biology, the GKSS Research Centre Geesthacht, the GFZ Helmholtz Centre Potsdam, the University of Hamburg on the DESY site, the light sources DORIS III, FLASH, PETRA III, and the European XFEL project, beamline enhancements and photon diagnostics at FLASH, undulator development for the European XFEL, special X-ray monochromators for PETRA III, high-power photon slits and shutters, the generation of brilliant beams, undulator demagnetization in LINAC based FELs, the control of experiments, advanced detection. (HSI)

  13. Beam extraction dynamics at the space-charge-limit of the high brightness E-XFEL electron source at DESY-PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ye; Gjonaj, Erion; Weiland, Thomas [TEMF, Technische Universitaet Darmstadt, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

    2015-07-01

    The physics of the photoemission, as one of the key issues for successful operation of linac based free-electron lasers like the European X-ray Free Electron Laser (E-XFEL) and the Free-electron Laser in Hamburg (FLASH), is playing an increasingly important role in the high brightness DESY-PITZ electron source. We study photoemission physics and discuss full three-dimensional numerical modeling of the electron bunch emission. The beam extraction dynamics at the photocathode has been investigated through the 3D fully electromagnetic (EM) Particle-in-Cell (PIC) solver of CST Particle Studio under the assumption of the photoemission source operating at or close to its space charge limit. PIC simulation results have shown good agreements with measurements on total emitted bunch charge for distinct experimental parameters. Further comparisons showed a general failure for the conventional Poisson solver based tracking algorithm to correctly predict the beam dynamics at the space charge limit. It is furthermore found, that fully EM PIC simulations are also consistent with a simple emission model based on the multidimensional Child-Langmuir law.

  14. Cryostat for Testing HIE-Isolde Superconducting RF Cavities

    CERN Document Server

    Capatina, O; Cuccuru, G; Pasini, M; Renaglia, T; Therasse, M; Vullierme, B

    2011-01-01

    The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN [1], with the objective of increasing the energy and intensity of the delivered radioactive ion beams (RIB). This project aims to fill the request for a more energetic post-accelerated beam by means of a new superconducting (SC) linac based on Quarter Wave Resonators (QWR). A research and development (R&D) programme looking at all the different aspects of the SC linac started in 2008 and continued throughout 2010. The R&D effort has particularly focused on the development of the high β cavities (β = 10.3%) for which the Nb sputtered on Cu substrate technology has been adopted. Two prototype cavities were manufactured and are undergoing RF cold tests. The pre-series cavity manufacturing is under way using 3D forged Cu billets. A single vacuum cryostat was designed and built to test these cavities at liquid helium temperatures. This paper details the main design concep...

  15. Dechirper Wakefields for Short Bunches

    CERN Document Server

    Bane, Karl

    2016-01-01

    In previous work [1] general expressions, valid for arbitrary bunch lengths, were derived for the wakefields of corrugated structures with flat geometry, such as is used in the RadiaBeam/LCLS dechirper. However, the bunch at the end of linac-based X-ray FELs--like the LCLS--is extremely short, and for short bunches the wakes can be considerably simplified. In this work, we first derive analytical approximations to the short-range wakes. These are generalized wakes, in the sense that their validity is not limited to a small neighborhood of the symmetry axis, but rather extends to arbitrary transverse offsets of driving and test particles. The validity of these short-bunch wakes holds not only for the corrugated structure, but rather for any flat structure whose beam-cavity interaction can be described by a surface impedance. We use these wakes to obtain, for a short bunch passing through a dechirper: estimates of the energy loss as function of gap, the transverse kick as function of beam offset, the slice ener...

  16. Wakefields of a Beam near a Single Plate in a Flat Dechirper

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl; Stupakov, Gennady; /SLAC; Zagorodnov, Igor; /DESY

    2016-11-29

    At linac-based, X-ray free electron lasers (FELs), there is interest in streaking the beam by inducing the transverse wakes in a flat dechirper, by passing the beam near to one of its two jaws. For LCLS-II - as has already been done for LCLS-I - this way of using the dechirper will e.g. facilitate two-color and fresh slice schemes of running the FEL. With the beam a distance from the near wall of say b ~ 0.25 mm and from the far wall by ≳ 5 mm, the second wall will no longer affect the results. The physics will be quite different from the two plate case: with two plates the impedance has a resonance spike whose frequency depends on the plate separation 2a; in the single plate case this parameter no longer exists. Formulas for the longitudinal, dipole, and quadrupole wakes for a beam off-axis between two dechirper plates, valid for the range of bunch lengths of interest in an X-ray FEL, are given in reference 3. By taking the proper limit, we can obtain the corresponding wakes for a beam close to one dechirper plate and far from the other. This is the task we perform in this note.

  17. CONDITIONS FOR CSR MICROBUNCHING GAIN SUPPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng Ying [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); di Mitri, Simone [Elettra–Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy

    2016-05-01

    The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to*. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver***. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain.

  18. Potential diagnostics for the next-generation light sources

    CERN Document Server

    Lumpkin, Alex H

    1999-01-01

    There is continued interest in developing a diffraction-limited soft or hard X-ray source. Candidate paths include the storage-ring-based free-electron laser (FEL) and the linac-based self-amplified spontaneous emission (SASE) FEL for the two regimes, respectively. As previously discussed, target beam parameters are sigma sub x sub , sub y approx 10 mu m, sigma sub x sub ' sub , sub y sub ' =1 mu rad, and sigma sub t approx 1 ps (0.1 ps for the linac case). We report the use of few- to sub-angstrom radiation emitted by a 7-GeV beam transitting a 198-period diagnostics undulator and a bending magnet to characterize the particle beam. A particle beam divergence as low as sigma sub y sub ' =3.3 mu rad was measured using an X-ray monochromator. Additionally, a particle beam size of sigma sub y <45 mu m and a bunch length of sigma sub t =28 ps with 4-ps resolution were measured using an X-ray pinhole camera with a unique synchroscan and dual-sweep X-ray streak camera as the detector. The adjustable pinhole aper...

  19. CERN Developments for 704 MHz Superconducting Cavities

    CERN Document Server

    Capatina, O; Aviles Santillana, I; Arnau Izquierdo, G; Bonomi, R; Calatroni, S; Chambrillon, J; Gerigk, F; Garoby, R; Guinchard, M; Junginger, T; Malabaila, M; Marques Antunes Ferreira, L; Mikulas, S; Parma, V; Pillon, F; Renaglia, T; Schirm, K; Tardy, T; Therasse, M; Vacca, A; Valverde Alonso, N; Vande Craen, A

    2013-01-01

    The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium beta=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the stat...

  20. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a ⁶⁰Co Magnetic Resonance Image Guidance Radiation Therapy System.

    Science.gov (United States)

    Wooten, H Omar; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H Harold; Mutic, Sasa

    2015-07-15

    This work describes a commercial treatment planning system, its technical features, and its capabilities for creating (60)Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. The ViewRay treatment planning system (Oakwood Village, OH) was used to create (60)Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The (60)Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. All (60)Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for (60)Co was within 20 Gy. The mean doses for all (60)Co plan OARs were within clinical tolerances. A commercial (60)Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Extreme hypofractionation for early prostate cancer: Biology meets technology.

    Science.gov (United States)

    De Bari, Berardino; Arcangeli, Stefano; Ciardo, Delia; Mazzola, Rosario; Alongi, Filippo; Russi, Elvio G; Santoni, Riccardo; Magrini, Stefano M; Jereczek-Fossa, Barbara A

    2016-11-01

    The aim of this review is to present the available radiobiological, technical and clinical data about extreme hypofractionation in primary prostate cancer radiotherapy. The interest in this technique is based on the favourable radiobiological characteristics of prostate cancer and supported by advantageous logistic aspects deriving from short overall treatment time. The clinical validity of short-term treatment schedule is proven by a body of non-randomised studies, using both isocentric (LINAC-based) or non-isocentric (CyberKnife(®)-based) stereotactic body irradiation techniques. Twenty clinical studies, each enrolling more than 40 patients for a total of 1874 treated patients, were revised in terms of technological setting, toxicity, outcome and quality of life assessment. The implemented strategies for the tracking of the prostate and the sparing of the rectal wall have been investigated with particular attention. The urinary toxicity after prostate stereotactic body irradiation seems slightly more pronounced as compared to rectal adverse events, and this is more evident for late occurring events, but no worse as respect to conventional fractionation schemes. As far as the rate of severe acute toxicity is concerned, in all the available studies the treatment was globally well tolerated. While awaiting long-term data on efficacy and toxicity, the analysed studies suggest that the outcome profile of this approach, alongside the patient convenience and reduced costs, is promising. Forty-eight ongoing clinical trials are also presented as a preview of the expectation from the near future.

  2. Analytical bunch compression studies for FLUTE

    CERN Document Server

    Schreck, M

    2014-01-01

    The current article deals with analytical bunch compression studies for FLUTE whose results are compared to simulations. FLUTE is a linac-based electron accelerator with a design energy of approximately 40 MeV currently being constructed at the Karlsruhe Institute of Technology. One of the goals of FLUTE is to generate electron bunches with their length lying in the femtosecond regime. In the first phase this will be accomplished using a magnetic bunch compressor. This compressor forms the subject of the studies presented. The paper is divided into three parts. The first part deals with pure geometric investigations of the bunch compressor where space charge effects and the back reaction of bunches with coherent synchrotron radiation (CSR) are neglected. The second part is dedicated to the treatment of space charge effects and the third part gives some analytical results on the emission of CSR. The upshot is that the results of the first and the third part agree quite well with what is obtained from simulatio...

  3. A Comparison of Helical Intensity-Modulated Radiotherapy, Intensity-Modulated Radiotherapy, and 3D-Conformal Radiation Therapy for Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Poppe, Matthew M.; Narra, Venkat; Yue, Ning J.; Zhou Jinghao; Nelson, Carl [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States); Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States); Jabbour, Salma K., E-mail: jabbousk@umdnj.edu [Department of Radiation Oncology, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT (United States); Department of Radiation Oncology, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (United States)

    2011-01-01

    We assessed dosimetric differences in pancreatic cancer radiotherapy via helical intensity-modulated radiotherapy (HIMRT), linac-based IMRT, and 3D-conformal radiation therapy (3D-CRT) with regard to successful plan acceptance and dose to critical organs. Dosimetric analysis was performed in 16 pancreatic cases that were planned to 54 Gy; both post-pancreaticoduodenectomy (n = 8) and unresected (n = 8) cases were compared. Without volume modification, plans met constraints 75% of the time with HIMRT and IMRT and 13% with 3D-CRT. There was no statistically significantly improvement with HIMRT over conventional IMRT in reducing liver V35, stomach V45, or bowel V45. HIMRT offers improved planning target volume (PTV) dose homogeneity compared with IMRT, averaging a lower maximum dose and higher volume receiving the prescription dose (D100). HIMRT showed an increased mean dose over IMRT to bowel and liver. Both HIMRT and IMRT offer a statistically significant improvement over 3D-CRT in lowering dose to liver, stomach, and bowel. The results were similar for both unresected and resected patients. In pancreatic cancer, HIMRT offers improved dose homogeneity over conventional IMRT and several significant benefits to 3D-CRT. Factors to consider before incorporating IMRT into pancreatic cancer therapy are respiratory motion, dose inhomogeneity, and mean dose.

  4. Analysis of High Order Modes in 1.3 GHZ CW SRF Electron Linac for a Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, A. [Fermilab; Vostrikov, A. [Fermilab; Yakovlev, V. [Fermilab

    2013-01-01

    Design of a Light Source (LS) based on the continuous wave superconducting RF (CW SRF) electron linac is currently underway. This facility will provide soft coherent X-ray radiation for a braod spectrum of basic research applications. Quality of the X-ray laser radiation is affected by the electron beam parameters such as the stability of the transverse beam position and longitudinal and transverse beam emittances. High order modes (HOMs) excited in the SRF structures by a passing beam may deteriorate the beam quality and affect the beam stability. Deposition of HOM energy in the walls of SRF cavities adds to the heat load of he cryogenic system and leads to the increased cost of building and operation of the linac. In this paper we evaluate effects of HOMs in an LS CW SRF linac based on Tesla-type 9-cell 1.3 GHz cavities. We analyze non-coherent losses and resonance excitation of HOMs. We estimate heat load due to the very high frequency HOMs. We study influence of the HOMs on the transverse beam dynamics.

  5. Deliverable D3 - Low- and Medium-beta linac

    CERN Document Server

    A. Facco, A. Balabin, R. Paparella, D. Zenere, INFN-Laboratori Nazionali di Legnaro, Padova, Italy; D. Berkovits, J. Rodnizki, SOREQ, Yavne, Israel; J. L. Biarrotte, S. Bousson, A. Ponton, G. Olry, IPN Orsay, France; R. Duperrier, D. Uriot, CEA/Saclay, France; V. Zvyagintsev, TRIUMF, Vancouver, Canada.

    The present document describes the Low- and Medium-beta section of the EURISOL DS Driver Accelerator. This section consists of a superconducting linac, based on Half-Wave (HWR) and SPOKE type resonators, preceded by a short, normal-conducting MEBT (Medium Energy Beam Transport) section that performs input beam matching. The scope of this linac is to bring the beams of H-, D+ and 3He++ produced by the Ion Injector (Deliverable D-5) to the energy and beam parameters required for injection in the superconducting High-beta linac (Deliverable D4-High beta linac). The present beam dynamics design reaches the goal of accelerating the required high current beams to the design energy (about 100 MeV/A, depending on the ion species), with minimum emittance growth and with low losses, using realistic and cost-effective, although innovative, technological solutions. The Low- and Medium-beta linac layout is described, together with the fundamental parameters and characteristics of its components and the system performanc...

  6. Deliverable D3 - Low- and Medium-beta linac

    CERN Document Server

    A. Facco, A. Balabin, R. Paparella, D. Zenere, INFN-Laboratori Nazionali di Legnaro, Padova, Italy; D. Berkovits, J. Rodnizki, SOREQ, Yavne, Israel; J. L. Biarrotte, S. Bousson, A. Ponton, G. Olry, IPN Orsay, France; R. Duperrier, D. Uriot, CEA/Saclay, France; V. Zvyagintsev, TRIUMF, Vancouver, Canada.

    The present document describes the Low- and Medium-beta section of the EURISOL DS Driver Accelerator. This section consists of a superconducting linac, based on Half-Wave (HWR) and SPOKE type resonators, preceded by a short, normal-conducting MEBT (Medium Energy Beam Transport) section that performs input beam matching. The scope of this linac is to bring the beams of H-, D+ and 3He++ produced by the Ion Injector (Deliverable D-5) to the energy and beam parameters required for injection in the superconducting High-beta linac (Deliverable D4-High beta linac). The present beam dynamics design reaches the goal of accelerating the required high current beams to the design energy (about 100 MeV/A, depending on the ion species), with minimum emittance growth and with low losses, using realistic and cost-effective, although innovative, technological solutions. The Low- and Medium-beta linac layout is described, together with the fundamental parameters and characteristics of its components and the system performance.

  7. Neutron time-of-flight spectroscopy measurement using a waveform digitizer

    Science.gov (United States)

    Liu, Long-Xiang; Wang, Hong-Wei; Ma, Yu-Gang; Cao, Xi-Guang; Cai, Xiang-Zhou; Chen, Jin-Gen; Zhang, Gui-Lin; Han, Jian-Long; Zhang, Guo-Qiang; Hu, Ji-Feng; Wang, Xiao-He

    2016-05-01

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the Thorium Molten Salt Reactor (TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal used for TOF calculation, with information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and γ-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The DAQ system developed is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy. Supported by Strategic Priority Research Program of the Chinese Academy of Science(TMSR) (XDA02010100), National Natural Science Foundation of China(NSFC)(11475245,No.11305239), Shanghai Key Laboratory of Particle Physics and Cosmology (11DZ2260700)

  8. Evaluation of nuclear data for R and D projects; development of database for medical nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Tae Suk [Catholic University, Seoul (Korea); Shin, D. O. [Kyung Hee University, Seoul (Korea); Joh, C. W.; Chang, J. S. [Ajou University, Suwon (Korea); Choi, Y. [Sungkyunkwan University, Seoul (Korea); Kim, S. H. [Hanyang University, Seoul (Korea); Park, S. Y. [National Cancer Center, Seoul (Korea); Shin, D. H.; Lee, S [Kyonggi University, Seoul (Korea)

    2002-04-01

    Medical nuclear data used in the country is not provided by academic associations and organizations concerned and even by government organizations concerned. This is aimed to investigate the diagnostic and therapeutic equipments in the clinical use and the domestic present status of nuclear data and physical properties of sealed or unsealed radioactive isotopes and to establish the nuclear database. About 120 domestic centers take nuclear medicine tests and 52 medical centers do radiotherapy. The 30-odd different kinds of radionuclides are usually used in nuclear medicine in the country. The 30-odd kinds of unsealed sources are used for diagnosis and therapy and 10-odd kinds of sealed sources for brachytherapy in the country. The special radiotherapy includes Gamma-knife, linac-based stereotactic radiosurgery, conformal radiotherapy and Intensity modulated radiotherapy. The nuclear data base has been completed on the basis of these data collected and the web site made is available with ease to anyone who want to get nuclear data. 39 refs., 20 figs., 8 tabs. (Author)

  9. Time-resolved pump-probe experiments at the LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Glownia, James; /SLAC /Stanford U., Appl. Phys. Dept.; Cryan, J.; /SLAC /Stanford U., Phys. Dept.; Andreasson, J.; /Uppsala U.; Belkacem, A.; /LBNL, Berkeley; Berrah, N.; /Western Michigan U.; Blaga, C.L.; /Ohio State U.; Bostedt, C.; Bozek, J.; /SLAC; DiMauro, L.F.; /Ohio State U.; Fang, L.; /Western Michigan U.; Frisch, J.; /SLAC; Gessner, O.; /LBNL; Guhr, M.; /SLAC; Hajdu, J.; /Uppsala U.; Hertlein, M.P.; /LBNL; Hoener, M.; /Western Michigan U. /LBNL; Huang, G.; Kornilov, O.; /LBNL; Marangos, J.P.; /Imperial Coll., London; March, A.M.; /Argonne; McFarland, B.K.; /SLAC /Stanford U., Phys. Dept. /SLAC /IRAMIS, Saclay /Stanford U., Phys. Dept. /Georgia Tech /Argonne /Kansas State U. /SLAC /Stanford U., Phys. Dept. /SLAC /Stanford U., Appl. Phys. Dept. /Stanford U., Appl. Phys. Dept. /SLAC /LBNL /Argonne /SLAC /SLAC /Stanford U., Appl. Phys. Dept. /Stanford U., Phys. Dept.

    2011-08-12

    The first time-resolved x-ray/optical pump-probe experiments at the SLAC Linac Coherent Light Source (LCLS) used a combination of feedback methods and post-analysis binning techniques to synchronize an ultrafast optical laser to the linac-based x-ray laser. Transient molecular nitrogen alignment revival features were resolved in time-dependent x-ray-induced fragmentation spectra. These alignment features were used to find the temporal overlap of the pump and probe pulses. The strong-field dissociation of x-ray generated quasi-bound molecular dications was used to establish the residual timing jitter. This analysis shows that the relative arrival time of the Ti:Sapphire laser and the x-ray pulses had a distribution with a standard deviation of approximately 120 fs. The largest contribution to the jitter noise spectrum was the locking of the laser oscillator to the reference RF of the accelerator, which suggests that simple technical improvements could reduce the jitter to better than 50 fs.

  10. submitter Introduction to Collective Effects in Particle Accelerators

    CERN Document Server

    Zimmermann, Frank

    2016-01-01

    The beam intensity and the beam brightness of particle accelerators or colliders operated for high - energy physics were, and are, often severely limited by “collective effects” (e.g.[1]). By contrast, new light sources, such as linac - based free electron lasers, may even rely on collective instabilities to accomplish their mission! The term “collective effects” refers to the interaction of beam particles with each other through a variety of processes, e.g. (1) non-delayed self-fields and image fields present even for constant perfectly conducting and magnetic boundaries (direct and indirect “space - charge effects”), (2) longer - lived electro-magnetic “wake fields” due to a finite chamber resistivity or geometric variation in the beam - pipe cross section, which typically affect later parts of the beam, (3) coherent synchrotron radiation, which on a curved trajectory may even influence earlier parts of the beam, giving rise to “non-causal” wake fields, otherwise not normally encountered...

  11. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Science.gov (United States)

    Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  12. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    Energy Technology Data Exchange (ETDEWEB)

    Rimjaem, S., E-mail: sakhorn.rimjaem@cmu.ac.th [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand); Kusoljariyakul, K.; Thongbai, C. [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics (ThEP), Commission on Higher Education, Bangkok 10400 (Thailand)

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012{sup ©}. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  13. Advances in radiation oncology in new millennium in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Seung Jae [College of Medicine, Sungkyunkwan Univ., Seoul (Korea, Republic of); Park, Charn Il [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    2000-06-01

    The objective of recent radiation therapy is to improve the quality of treatment and the after treatment quality of life. In Korea, sharing the same objective, significant advancement was made due to the gradual increase of patient number and rapid increase of treatment facilities. The advancement includes generalization of three-dimensional conformal radiotherapy (3D-CRT), application of linac-based stereotactic radiosurgery (SRS), and furthermore, the introduction of intensity modulated radiation therapy (IMRT). Authors in this paper prospectively review the followings: the advancement of radiation oncology in Korea, the recent status of four-dimensional radiation therapy. IMRT, the concept of the treatment with biological conformity, the trend of combined chemoradiotherapy, the importance of internet and radiation oncology information management system as influenced by the revolution of information technology, and finally the global trend of telemedicine in radiation oncology. Additionally, we suggest the methods to improve radiotherapy treatment, which include improvement of quality assurance (QA) measures by developing Koreanized QA protocol and system, regional study about clinical protocol development for phase three clinical trial, suggestion of unified treatment protocol and guideline by academic or research societies, domestic generation of treatment equipment's or system, establishment of nationwide data base of radiation-oncology-related information, and finally pattems-of-care study about major cancers.

  14. X-ray tomography system for industrial applications

    Science.gov (United States)

    Auditore, L.; Barna, R. C.; Emanuele, U.; Loria, D.; Trifiro, A.; Trimarchi, M.

    2008-05-01

    X-ray radiography and tomography are two of the most used non-destructive testing techniques both in industrial and cultural heritage fields. However, the inspection of heavy materials or thick objects requires X-ray energies larger than the maximum energy provided by commercial X-ray tubes (600 kV). For this reason, and owing to the long experience of the INFN-Gruppo Collegato di Messina in designing and assembling low energy electron linacs, a 5 MeV electron linac based X-ray tomographic system has been developed at the Dipartimento di Fisica, Università di Messina. The X-ray source, properly designed, provides a 16 cm diameter X-ray spot at the sample position, and a beam opening angle of about 3.6 degree. Optimization of the parameters influencing the e-γ conversion and the X-ray beam characteristics have been studied by means of the MCNP-4C2 (Monte-Carlo-N-Particle, version 4C2) code. The image acquisition system consists of a CCD camera and a scintillator screen. Preliminary radiographies and tomographies showing the high quality performances of the tomographic system have been acquired. Finally, the compactness of the accelerator system is one of the advantages of the discussed tomography device which could be made transportable.

  15. High-intensity positron microprobe at Jefferson Lab

    CERN Document Server

    Golge, Serkan; Wojtsekhowski, Bogdan

    2014-01-01

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 10$^{10}$ e$^+$/s. Reaching this intensity in our design relies on the transport of positrons (T$_+$ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effective...

  16. X-ray Sources by Energy Recovered Linacs and Their Needed R&D

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey Krafft, Stephen Benson, Michael Borland, David Douglas, David Dowell, Carlos Hernandez-Garcia, Dmitry Kayran, Robert Legg, Elizabeth Moog, Takashi Obina, Robert Rimmer, Vitaly Yakimenko

    2011-05-01

    In this paper we review the current state of research on energy recovered linacs as drivers for future X-ray sources. For many types of user experiments, such sources may have substantial advantages compared to the workhorse sources of the present: high energy storage rings. Energy recovered linacs need to be improved beyond present experience in both energy and average current to support this application. To build an energy recovered linac based X-ray user facility presents many interesting challenges. We present summaries on the Research and Development (R&D) topics needed for full development of such a source, including the discussion at the Future Light Sources Workshop held in Gaithersberg, Maryland on September 15-17, 2009. A first iteration of an R&D plan is presented that is founded on the notion of building a set of succeedingly larger test accelerators exploring cathode physics, high average current injector physics, and beam recirculation and beam energy recovery at high average current. Our basic conclusion is that a reviewable design of such a source can be developed after an R&D period of reasonably short duration.

  17. A proposed VUV oscillator-based FEL upgrade at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S. V. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Douglas, D. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Evtushenko, P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hannon, F. E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hernandez-Garcia, C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Klopf, J. M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Legg, R. A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Neil, G. R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Shinn, M. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, C. D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Williams, G. P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2011-09-20

    Advances in superconducting linac technology offer the possibility of an upgrade of the Jefferson Lab Free Electron Laser (JLab FEL) facility to an oscillator-based VUV-FEL that would produce 6 x 10{sup 12} coherent 100 eV photons per pulse at multi-MHz repetition rates in the fundamental. At present JLab operates a pair of oscillator-based continuous-wave Free Electron Lasers (FELs) as a linac-based next generation light source in the IR and UV, with sub-picosecond pulses up to 75 MHz. Harmonics upwards of 10 eV are produced and the fully coherent nature of the source results in peak and average brightness values that are several orders of magnitude higher than storage rings. The accelerator uses an energy recovered linac design for efficiency of operation. New style superconducting linac cryomodules with higher gradient, combined with a new injector and beam transport system allow the development of the FEL to higher photon energies.

  18. High Frequency Linacs for Hadrontherapy

    Science.gov (United States)

    Amaldi, Ugo; Braccini, Saverio; Puggioni, Paolo

    The use of radiofrequency linacs for hadrontherapy was proposed about 20 years ago, but only recently has it been understood that the high repetition rate together with the possibility of very rapid energy variations offers an optimal solution to the present challenge of hadrontherapy: "paint" a moving tumor target in three dimensions with a pencil beam. Moreover, the fact that the energy, and thus the particle range, can be electronically adjusted implies that no absorber-based energy selection system is needed, which, in the case of cyclotron-based centers, is the cause of material activation. On the other side, a linac consumes less power than a synchrotron. The first part of this article describes the main advantages of high frequency linacs in hadrontherapy, the early design studies, and the construction and test of the first high-gradient prototype which accelerated protons. The second part illustrates some technical issues relevant to the design of copper standing wave accelerators, the present developments, and two designs of linac-based proton and carbon ion facilities. Superconductive linacs are not discussed, since nanoampere currents are sufficient for therapy. In the last two sections, a comparison with circular accelerators and an overview of future projects are presented.

  19. Beam dynamics and expected performance of Sweden’s new storage-ring light source: MAX IV

    Directory of Open Access Journals (Sweden)

    S. C. Leemann

    2009-12-01

    Full Text Available MAX IV will be Sweden’s next-generation high-performance synchrotron radiation source. The project has recently been granted funding and construction is scheduled to begin in 2010. User operation for a broad and international user community should commence in 2015. The facility is comprised of two storage rings optimized for different wavelength ranges, a linac-based short-pulse facility and a free-electron laser for the production of coherent radiation. The main radiation source of MAX IV will be a 528 m ultralow emittance storage ring operated at 3 GeV for the generation of high-brightness hard x rays. This storage ring was designed to meet the requirements of state-of-the-art insertion devices which will be installed in nineteen 5 m long dispersion-free straight sections. The storage ring is based on a novel multibend achromat design delivering an unprecedented horizontal bare lattice emittance of 0.33 nm rad and a vertical emittance below the 8 pm rad diffraction limit for 1 Å radiation. In this paper we present the beam dynamics considerations behind this storage-ring design and detail its expected unique performance.

  20. lightsources.org: An Internet Site for Light SourceCommunication

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Art

    2004-10-04

    Research at the world's accelerator- (storage-ring and linac) based light sources is one of the most dynamic and rapidly growing fields of science. It frequently results in direct benefits to society, thereby demonstrating the value of the research with very concrete examples, but this is not widely understood or appreciated outside of the immediate user community. Our growing group of light source communicators from facilities in Europe, Asia, and the Americas, inspired by the Interactions.org Web site created by high-energy (elementary-particle)physics communicators, concluded that a light source community Web site (lightsources.org) would be the best tool for establishing effective collaboration between the communications offices of the world's light sources and to maximize the impact of our efforts. We envision lightsources.org to serve as a one-stop-shopping site for information about all aspects of light sources and the research they make possible. Audiences to be served include science communicators, the press, policymakers, the light source community, the wider scientific community, the science-interested public, and students and educators. Our proposal has been sent to the world's light source facility directors by J. Murray Gibson (APS) and William G. Stirling (ESRF). As a result,light sources.org is now being supported by a growing list of facilities from Europe, North America, and Asia. We hope to launch lightsources.org before the end of 2004.

  1. Active Interrogation using Photofission Technique for Nuclear Materials Control and Accountability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haori [Oregon State Univ., Corvallis, OR (United States)

    2016-03-31

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. In addition to thermal or high-energy neutrons, high-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. Electron linear accelerators (linacs) are widely used as the interrogating photon sources for inspection methods involving photofission technique. After photofission reactions, prompt signals are much stronger than the delayed signals, but it is difficult to quantify them in practical measurements. Delayed signals are easily distinguishable from the interrogating radiation. linac-based, advanced inspection techniques utilizing the delayed signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope.

  2. Beam-Based Procedures for RF Guns

    CERN Document Server

    Krasilnikov, Mikhail; Grabosch, H J; Hartrott, Michael; Hui Han, Jang; Miltchev, Velizar; Oppelt, Anne; Petrosyan, Bagrat; Staykov, Lazar; Stephan, Frank

    2005-01-01

    A wide range of rf photo injector parameters has to be optimized in order to achieve an electron source performance as required for linac based high gain FELs. Some of the machine parameters can not be precisely controlled by direct measurements, whereas the tolerance on them is extremely tight. Therefore, this should be met with beam-based techniques. Procedures for beam-based alignment (BBA) of the laser on the photo cathode as well as solenoid alignment have been developed. They were applied at the Photo Injector Test facility at DESY Zeuthen (PITZ) and at the photo injector of the VUV-FEL at DESY Hamburg. A field balance of the accelerating mode in the 1 ½ cell gun cavity is one of the key beam dynamics issues of the rf gun. Since no direct field measurement in the half and full cell of the cavity is available for the PITZ gun, a beam-based technique to determine the field balance has been proposed. A beam-based rf phase monitoring procedure has been developed as well.

  3. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Science.gov (United States)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

    2014-02-01

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  4. Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik, E-mail: hskang@postech.ac.kr [Pohang Accelerator Laboratory, San31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

    2014-02-14

    An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E < 12.47% for 99% particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 10{sup 11} n/cm{sup 2}/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

  5. Design and parameter optimization of a small-scale electron-based ADS for radioactive waste transmutation

    Science.gov (United States)

    Feizi, H.; Ranjbar, A. H.

    2015-05-01

    This paper presents the design and feasibility of an electron-LINAC-based small-scale system (ADS) for nuclear waste transmutation. FLUKA simulations have been performed to evaluate the photoneutron yield in high- Z metallic targets such as silver, tungsten, lead, tantalum and uranium irradiated by electron beams of 20-200MeV. The parameters involved in the photoneutron production mechanism including electron beam energy, target material and target shape have been investigated in order to obtain maximum photoneutron production. The neutron reflectors of the ADS, in particular, beryllium, lead and beryllium oxide (BeO) with various thicknesses have been studied. The results show that a combination of an internal reflector of Pb with a thickness of 3cm and an external reflector of BeO with a thickness of 10cm improves the fluence rate. The photoneutron energy spectrum, photoneutron fluence distribution and heat deposition in the electron target have also been presented. At incident electron beam energy of 155MeV, a neutron source of ˜ 4.6 × 1010 (n/cm2/s/mA) has been achieved, which is highly applicable for using in nuclear waste transmutation. The designed ADS has the ability to transmute ˜ 1.5 × 1022 (atoms/y/mA). The obtained results are promising and could lead to the development of a small-scale ADS based on electron LINAC for radioactive waste transmutation and for numerous applications when employed as a photoneutron source.

  6. Seeding the FEL of the SCSS Phase 1 Facility with the 13th Laser Harmonic of a Ti-Sa Laser Produced in Xe Gas

    CERN Document Server

    Lambert, G

    2005-01-01

    In order to reach very short wavelengths in systems based on Free Electrons Laser (FEL), and to have a more compact, fully coherent and tunable source, a particular seeding configuration is studied here. It is foreseen to test it as a demonstration experiment in 2006 into the SCSS phase 1 facility (Spring-8 Compact Sase Source, Japan). SCSS phase 1 is a linac-based FEL project, providing a compact SASE source with high brightness in the X-ray range. The external laser source, which is employed, is straightfully in the XUV range, the 13th harmonic of a Ti:Sa femtosecond laser (61.5 nm), generated in Xe gas. This harmonic can be now easily generated by focusing the Ti: Sa laser (25 mJ, 10 Hz, 100 fs) on a 10 Hz pulsed Xe gas cell. This High order Harmonics Generation (HHG) process provides us with a VUV beam with intense (1 μJ) and ultra-short (50 fs) properties.

  7. Preliminary study of EEHG-based superradiant undulator radiation at the HLS-II storage ring

    Science.gov (United States)

    Gao, Wei-Wei; Li, He-Ting; Wang, Lin

    2017-07-01

    We investigate storage ring-based Echo-Enabled Harmonic Generation (EEHG) superradiant undulator radiation as a possible scheme to obtain shorter wavelengths at the HLS-II (Hefei Light Source-II) storage ring. In this paper we give the designation of the storage ring based EEHG up to the 26th harmonic, where 31 nm vacuum ultraviolet light is radiated from an 800 nm seeded laser. The novelty of our design is that both the two dispersion sections of EEHG are realized by the storage ring’s own magnet structure. In particular, the whole ring is used as the first dispersion section, and two modulators of the traditional EEHG can be done with the same undulator. These two dispersion sections are realized by changing the superperiod of the present lattice structure, and more precisely by changing the focusing strengths of the present structure. Since no additional magnets and chicanes are used, the beam circulates around the storage ring repeatedly, and thus this storage ring-based EEHG can have a higher repetition rate than a linac-based EEHG. Supported by National Natural Science Foundation of China (11305170)

  8. Overview of High Power Vacuum Dry RF Load Designs

    Energy Technology Data Exchange (ETDEWEB)

    Krasnykh, Anatoly [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    A specific feature of RF linacs based on the pulsed traveling wave (TW) mode of operation is that only a portion of the RF energy is used for the beam acceleration. The residual RF energy has to be terminated into an RF load. Higher accelerating gradients require higher RF sources and RF loads, which can stably terminate the residual RF power. RF feeders (from the RF source though the accelerating section to the load) are vacuumed to transmit multi-megawatt high power RF. This overview will outline vacuumed RF loads only. A common method to terminate multi-MW RF power is to use circulated water (or other liquid) as an absorbing medium. A solid dielectric interface (a high quality ceramic) is required to separate vacuum and liquid RF absorber mediums. Using such RF load approaches in TW linacs is troubling because there is a fragile ceramic window barrier and a failure could become catastrophic for linac vacuum and RF systems. Traditional loads comprising of a ceramic disk have limited peak and average power handling capability and are therefore not suitable for high gradient TW linacs. This overview will focus on ''vacuum dry'' or ''all-metal'' loads that do not employ any dielectric interface between vacuum and absorber. The first prototype is an original design of RF loads for the Stanford Two-Mile Accelerator.

  9. Design of APhF-IH Linac for a Compact Medical Accelerator

    CERN Document Server

    Kapin, V; Iwata, Y

    2003-01-01

    The design of a small injection linac for a compact medical synchrotron is discussed. The linac design is based on interdigital H-type (IH) drift-tube structure with alternative phase focusing (APhF). A high acceleration rate and an absence of magnetic lenses inside drift-tubes reduce the cost and length of APhF-IH linac in comparison with HIMAC linac based on Alvarez structure with magnet quadrupoles inside drift-tubes. To reduce effects of emittance growth, the RFQ structure is used in front of the APhF linac. In such linac layout, the current transmission of a carbon beam can reach up to 90-100%. In this report, the basic parameters of whole linac are presented, while the design of APhF structure is considered in details. Two reference designs of 4 MeV/u 200 MHz APhF linacs with different voltage distributions along the whole tank have been generated and analyzed numerically. For the first design, a constant voltage distribution along the tank is assumed. The total length of the structure is about 4.2 m. F...

  10. Design study of the bending sections between harmonic cascade FEL stages

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Weishi; Corlett, John; Fawley, William; Zholents, A.

    2004-06-30

    The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.

  11. Status of the Superconducting Proton Linac (SPL) Cryo-Module

    CERN Document Server

    Parma, V; Capatina, O; Chambrillon, J; Montesinos, E; Schirm, K; Vande Craen, A; Vandoni, G; Van Weelderen, R

    2014-01-01

    The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art SRF technology. Such an accelerator could serve as a driver in new physics facilities for neutrinos and/or radioactive ion beams [1]. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium beta=1 elliptical cavities (operating at 2 K and providing an accelerating gradient of 25 MV/m) and the test of a string of cavities integrated in a machine-type cryo-module. In an initial phase, only four out of the eight cavities of the SPL cryo-module will be tested in a half-length cryo-module developed for this purpose, which nonetheless preserves the main features of the full size module. This paper presents the final design of the cryo-module and the status of the construction of the main cryostat parts. Preliminary plans for the assembly a...

  12. Investigation of slice emittance using an energy-chirped electron beam in a dispersive section for photo injector characterization at PITZ

    Energy Technology Data Exchange (ETDEWEB)

    Ivanisenko, Yevgeniy

    2012-06-15

    This work describes a transverse slice emittance diagnostics with an RMS temporal resolution down to 2 ps that was implemented at the Photo Injector Test facility in Zeuthen (PITZ). The measurements were performed for several bunch charges generated by a laser pulse that has a flat-top temporal profile of 21-22 ps FWHM duration. This diagnostics allows to study the beam projected emittance compensation with a solenoid magnetic field experimentally and therefore contributes to the beam emittance optimization for the needs of short wavelength linac-based FELs in particular. The diagnostics is based upon the usage of electron bunches which have a correlation between the longitudinal position and the momentum of the bunch particles. This property allows to convert the bunch longitudinal distribution into a transverse one in a dipole magnet. A slit with a narrow opening at the dipole exit selects a fraction of the particle ensemble, a slice, which emittance is analyzed at a screen downstream. Slit scan and quadrupole scan techniques can be used to measure the emittance of the slices. In the experiments it was found that the slice emittance values are 5-10% lower than the projected emittance values, indicating a good effectivity of the solenoid compensation. The emittance obtained using quadrupole scan technique has shown different results when compared to slit scan technique due to a beam halo. The observed beam halo in phase space contributes up to 40% of the emittance value while having only 10% of the bunch charge.

  13. Initial studies of Bremsstrahlung energy deposition in small-bore superconducting undulator structures in linac environments

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, T.; Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    One of the more promising technologies for developing minimal-length insertion devices for linac-driven, single-pass Free Electron Lasers (FELs) operating in the x-ray range is based on the use of superconducting (SC) materials. In recent FEL simulations, for example, a bifilar helical SC device with a 2 cm period and 1.8 T field was found to require a 30 m saturation length for operation at 1.5{Angstrom} on a 15 GeV linac, more than 40% shorter than an alternative hybrid/permanent magnet (hybrid/PM) undulator. AT the same time, however, SC technology is known to present characteristic difficulties for insertion device design, both in engineering detail and in operation. Perhaps the most critical problem, as observed, e.g., by Madey and co-workers in their initial FEL experiments, was the frequent quenching induced by scattered electrons upstream of their (bifilar) device. Postulating that this quenching was precipitated by directly-scattered or bremsstrahlung-induced particle energy deposited into the SC material or into material contiguous with it, the importance of numerical and experimental characterizations of this phenomenon for linac-based, user-facility SC undulator design becomes evident. In this paper we discuss selected prior experimental results and report on initial EGS4 code studies of scattered and bremsstrahlung induced particle energy deposition into SC structures with geometries comparable to a small-bore bifilar helical undulator.

  14. Multi-channel medical imaging system

    Science.gov (United States)

    Frangioni, John V

    2013-12-31

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remain in the subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may provide an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide used to capture images. The system may be configured for use in open surgical procedures by providing an operating area that is closed to ambient light. The systems described herein provide two or more diagnostic imaging channels for capture of multiple, concurrent diagnostic images and may be used where a visible light image may be usefully supplemented by two or more images that are independently marked for functional interest.

  15. Simulations of Laser Pulse Coupling and Transmission Efficiency in Plasma Channels

    CERN Document Server

    Giacone, Rodolfo; Cary, John R; Dimitrov, Dimitre; Esarey, Eric; Geddes, Cameron G R; Leemans, Wim; Messmer, Peter

    2005-01-01

    Optical guiding of the laser pulse in a laser wakefield accelerator (LWFA) via plasma channels can greatly increase the interaction length and, hence, the maximun energy of trapped electrons.* Energy efficient coupling of laser pulses from vacuum into plasma channels is very important for optimal LWFA performance. We present 2D particle-in-cell simulations of this problem using the VORPAL code.** Some of the mechanisms considered are enhanced leakage of laser energy transversely through the channel walls, enhanced refraction due to tunneling ionization of neutral gas on the periphery of the gas jet, ionization of neutral gas by transverse wings of the laser pulse and effect of the pulse being off axis of the channel. Using power spectral diagnostics,*** we are able to differentiate between pump depletion and leakage from the channel. The results from our simulations show that for short (≈λp

  16. Deposited low temperature silicon GHz modulator

    CERN Document Server

    Lee, Yoon Ho Daniel; Lipson, Michal

    2013-01-01

    The majority of silicon photonics is built on silicon-on-insulator (SOI) wafers while the majority of electronics, including CPUs and memory, are built on bulk silicon wafers, limiting broader acceptance of silicon photonics. This discrepancy is a result of silicon photonics's requirement for a single-crystalline silicon (c-Si) layer and a thick undercladding for optical guiding that bulk silicon wafers to not provide. While the undercladding problem can be partially addressed by substrate removal techniques, the complexity of co-integrating photonics with state-of-the-art transistors and real estate competition between electronics and photonics remain problematic. We show here a platform for deposited GHz silicon photonics based on polycrystalline silicon with high optical quality suitable for high performance electro-optic devices. We demonstrate 3 Gbps polysilicon electro-optic modulator fabricated on a deposited polysilicon layer fully compatible with CMOS backend integration. These results open up an arr...

  17. Biocompatible PEGylated gold nanorods as colored contrast agents for targeted in vivo cancer applications

    Science.gov (United States)

    Kopwitthaya, Atcha; Yong, Ken-Tye; Hu, Rui; Roy, Indrajit; Ding, Hong; Vathy, Lisa A.; Bergey, Earl J.; Prasad, Paras N.

    2010-08-01

    In this contribution, we report the use of a PEGylated gold nanorods formulation as a colored dye for tumor labeling in vivo. We have demonstrated that the nanorod-targeted tumor site can be easily differentiated from the background tissues by the 'naked eye' without the need of sophisticated imaging instruments. In addition to tumor labeling, we have also performed in vivo toxicity and biodistribution studies of PEGylated gold nanorods in vivo by using BALB/c mice as the model. In vivo toxicity studies indicated no mortality or adverse effects or weight changes in BALB/c mice treated with PEGylated gold nanorods. This finding will provide useful guidelines in the future development of diagnostic probes for cancer diagnosis, optically guided tumor surgery, and lymph node mapping applications.

  18. Multi-channel medical imaging system

    Science.gov (United States)

    Frangioni, John V.

    2016-05-03

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remain in a subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may provide an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide used to capture images. The system may be configured for use in open surgical procedures by providing an operating area that is closed to ambient light. The systems described herein provide two or more diagnostic imaging channels for capture of multiple, concurrent diagnostic images and may be used where a visible light image may be usefully supplemented by two or more images that are independently marked for functional interest.

  19. Summary of the transfer of optical processing to systems: optical pattern recognition program

    Science.gov (United States)

    Lindell, Scott D.

    1995-06-01

    Martin Marietta has successfully completed a TOPS optical pattern recognition program. The program culminated in August 1994 with an automatic target recognition flight demonstration inwhich an M60A2 tank was acquired, identified, and tracked with a visible seeker from a UH-1 helicopter flying a fiber optic guided missile (FOG-M) mission profile. The flight demonstration was conducted by the US Army Missile Command (MICOM) and supported by Martin Marietta. The pattern recognition system performance for acquiring and identifying the M60A2 tank, which was positioned among an array with five other vehicle types, was 90% probability of correct identification and a 4% false identification for over 40,000 frames of imagery processed. Imagery was processed at a 15 Hz input rate with a 1 ft3, 76 W, 4 GFLOP processor performing up to 800 correlations per second.

  20. Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

    Energy Technology Data Exchange (ETDEWEB)

    Martínez de Mendívil, Jon; Pérez Delgado, Alberto; Lifante, Ginés; Jaque, Daniel [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Ródenas, Airán [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Benayas, Antonio, E-mail: antonio.benayas@emt.inrs.ca [Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049 (Spain); Institut National de la Recherche Scientifique, Centre – Énergie Matériaux et Télécommunications, 1650, Boul. Lionel Boulet Varennes, Quebec J3X 1S2 (Canada); Aguiló, Magdalena; Diaz, Francesc [Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona 43007 (Spain); Kar, Ajoy K. [Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2015-01-14

    The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution.

  1. Multi-channel medical imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Frangioni, John V.

    2016-05-03

    A medical imaging system provides simultaneous rendering of visible light and fluorescent images. The system may employ dyes in a small-molecule form that remain in a subject's blood stream for several minutes, allowing real-time imaging of the subject's circulatory system superimposed upon a conventional, visible light image of the subject. The system may provide an excitation light source to excite the fluorescent substance and a visible light source for general illumination within the same optical guide used to capture images. The system may be configured for use in open surgical procedures by providing an operating area that is closed to ambient light. The systems described herein provide two or more diagnostic imaging channels for capture of multiple, concurrent diagnostic images and may be used where a visible light image may be usefully supplemented by two or more images that are independently marked for functional interest.

  2. Fluorescence imaging of lattice re-distribution on step-index direct laser written Nd:YAG waveguide lasers

    Science.gov (United States)

    Martínez de Mendívil, Jon; Ródenas, Airán; Benayas, Antonio; Aguiló, Magdalena; Diaz, Francesc; Pérez Delgado, Alberto; Lifante, Ginés; Jaque, Daniel; Kar, Ajoy K.

    2015-01-01

    The laser performance and crystalline micro-structural properties of near-infrared step-index channel waveguides fabricated inside Neodymium doped YAG laser ceramics by means of three-dimensional sub-picosecond pulse laser direct writing are reported. Fluorescence micro-mapping of the waveguide cross-sections reveals that an essential crystal lattice re-distribution has been induced after short pulse irradiation. Such lattice re-distribution is evidenced at the waveguide core corresponding to the laser written refractive index increased volume. The waveguides core surroundings also present diverse changes including slight lattice disorder and bi-axial strain fields. The step-index waveguide laser performance is compared with previous laser fabricated waveguides with a stress-optic guiding mechanism in absence of laser induced lattice re-distribution.

  3. Particle-In-Cell Modeling of Plasma-Based Accelerators in Two and Three Dimensions

    CERN Document Server

    Hemker, Roy G

    2015-01-01

    In this dissertation, a fully object-oriented, fully relativistic, multi-dimensional Particle-In-Cell code was developed and applied to answer key questions in plasma-based accelerator research. The simulations increase the understanding of the processes in laser plasma and beam-plasma interaction, allow for comparison with experiments, and motivate the development of theoretical models. The simulations support the idea that the injection of electrons in a plasma wave by using a transversely propagating laser pulse is possible. The beam parameters of the injected electrons found in the simulations compare reasonably with beams produced by conventional methods and therefore laser injection is an interesting concept for future plasma-based accelerators. Simulations of the optical guiding of a laser wakefield driver in a parabolic plasma channel support the idea that electrons can be accelerated over distances much longer than the Rayleigh length in a channel. Simulations of plasma wakefield acceleration in the ...

  4. Design of folded holographic spectrum-splitting photovoltaic system for direct and diffuse illumination conditions

    Science.gov (United States)

    Wu, Yuechen; Vorndran, Shelby D.; Russo, Juan M.; Ayala, Silvana; Kostuk, Raymond K.

    2014-10-01

    Spectrum-splitting is a beneficial technique to increase the efficiency and reduce the cost of photovoltaic (PV) systems. This method divides the incident solar spectrum into spectral components that are spatially separated and directed to PV cells with matching spectral responsivity characteristics. This approach eliminates problems associated with current and lattice matching that must be maintained in tandem multi-junction systems. In this paper, a two-junction holographic spectrum-splitting photovoltaic system is demonstrated with a folded PV geometry. The system is designed to use both direct and diffuse solar irradiation. It consists of holographic elements, a wedge-shaped optical guide, and PV substrates with back reflectors. The holographic elements and back reflectors spatially separate the incident solar spectrum and project spectral components onto matching PV cell types. In addition, the wedge-shaped optical guide traps diffuse illumination inside the system to increase absorption. In this paper, the wedge spectrum splitting system is analyzed using tabulated data for InGaP2/GaAs cells with direct illumination combined with experimental data for reflection volume holograms. A system efficiency of 31.42% is obtained with experimental reflection hologram data. This efficiency is a 21.42% improvement over a similar system that uses one PV cell with the highest efficiency (GaAs). Simulation results show large acceptance angle for both in-plane and out-of plane directions. Simulation of the output power of the system with different configurations at different times of the year are also presented.

  5. Efficiency of scalp epileptiform discharge dipole for stereotactic radiofrequency to refactory mesial temporal lobe epilepsy%(癎)样放电偶极子对颞叶内侧型顽固性癫(癎)的定位价值

    Institute of Scientific and Technical Information of China (English)

    吴朝晖; 田增民; 赵全军; 张剑宁; 肖霞; 王红; 林鸿; 王福莉

    2012-01-01

    目的:探讨(癎)样放电偶极子分析结合临床特征和其它无创检查对颞叶内侧型顽固性癫(癎)的定位价值.方法:对21例发作间期主要在颞区存在(癎)样放电且每月致残性发作1次以上的顽固性癫(癎)患者,结合临床特征和其它无创检查确诊为颞叶内侧型癫(癎)并定侧后,进行机器人辅助立体定向射频热凝毁损颞叶内侧结构治疗.结果:术后12~37个月,按照Engel分级系统:Ⅰ级6例(29%,其中Ⅰa级5例,Ⅰd级1例),Ⅱb级3例(14%),Ⅳa级4例(19%),Ⅳb级7例(30%),Ⅳc级1例(5%).术后患者的神经功能均无明显下降.结论:机器人辅助立体定向系统射频热凝毁损术安全、有效、方便、快捷,部分颞叶内侧型顽固性癫(癎)患者对立体定向射频热凝治疗反应良好.%To investigate the efficiency of scalp epileptiform discharge dipole,ictal character and other non-ivasive tests for stereotactic radiofrequency to refactory mesial temporgllobe epilepsy by robot assistant f rameless stereotaxy. Methods: Twenty-one patients with interictal epileptiform discharge in the temporal area located in mesial temporal lobe by spike-sharp dipole were diagnosed as the cases with mesial temporal lobe epilepsy with ictal character by epileptiform discharge dipole analysis and other non-ivasive tests. All the patients had disabling seizure at least once per month,and were refactory to antiepileptic drug. They all accepted transfrontal mesial temporal lobe radiofrequency thermocoagula-tion performed by robot assistant frameless system. Results: The postoperative outcomes were evaluated according to Engel classification: 6(29%) patients achieved Engel class I (including 5 I a,l I d),3 (14%) Engel classU.b, 4(19%) Engel class IVa,7(30%) Engel class IVb.and 1(5%) Engel IVc. No one had permanently functional disability. Conclusion; Robot assistant frameless stereotaxy for radiofrequency thermocoagulation is safe,effective,convenient and swift

  6. Accuracy evaluation of the optical surface monitoring system on EDGE linear accelerator in a phantom study.

    Science.gov (United States)

    Mancosu, Pietro; Fogliata, Antonella; Stravato, Antonella; Tomatis, Stefano; Cozzi, Luca; Scorsetti, Marta

    2016-01-01

    Frameless stereotactic radiosurgery (SRS) requires dedicated systems to monitor the patient position during the treatment to avoid target underdosage due to involuntary shift. The optical surface monitoring system (OSMS) is here evaluated in a phantom-based study. The new EDGE linear accelerator from Varian (Varian, Palo Alto, CA) integrates, for cranial lesions, the common cone beam computed tomography (CBCT) and kV-MV portal images to the optical surface monitoring system (OSMS), a device able to detect real-time patient׳s face movements in all 6 couch axes (vertical, longitudinal, lateral, rotation along the vertical axis, pitch, and roll). We have evaluated the OSMS imaging capability in checking the phantoms׳ position and monitoring its motion. With this aim, a home-made cranial phantom was developed to evaluate the OSMS accuracy in 4 different experiments: (1) comparison with CBCT in isocenter location, (2) capability to recognize predefined shifts up to 2° or 3cm, (3) evaluation at different couch angles, (4) ability to properly reconstruct the surface when the linac gantry visually block one of the cameras. The OSMS system showed, with a phantom, to be accurate for positioning in respect to the CBCT imaging system with differences of 0.6 ± 0.3mm for linear vector displacement, with a maximum rotational inaccuracy of 0.3°. OSMS presented an accuracy of 0.3mm for displacement up to 1cm and 1°, and 0.5mm for larger displacements. Different couch angles (45° and 90°) induced a mean vector uncertainty < 0.4mm. Coverage of 1 camera produced an uncertainty < 0.5mm. Translations and rotations of a phantom can be accurately detect with the optical surface detector system.

  7. A-mode ultrasound-based registration in computer-aided surgery of the skull.

    Science.gov (United States)

    Amstutz, Christoph; Caversaccio, Marco; Kowal, Jens; Bächler, Richard; Nolte, Lutz-Peter; Häusler, Rudolf; Styner, Martin

    2003-12-01

    To evaluate the integration and accuracy of A (amplitude)-mode ultrasound-based surface matching for noninvasive registration of the head into a frameless computer-aided surgery system for otorhinology and skull base surgery. Experimental study and case series. Academic medical center. Twelve patients underwent anterior and paranasal skull base surgery with the routine use of a computer-aided surgery system. A computer-aided surgery system, based on an optoelectronic localizer, was used to track the skull and the surgical tools, including the A-mode ultrasound probe. The A-mode probe was a 10-MHz immersion transducer. An acoustic lens attached to the transducer focused the ultrasonic beam to a depth of 1 to 10 mm. Accuracy tests were performed for the ultrasound setup. Different surface point distributions were evaluated with respect to matching accuracy on a human cadaver skull specimen equipped with fiducial markers. The matching comparison was based on the fiducial registration error. For the clinical evaluation, the laboratory setup was transferred to the operating room. Noninvasive registration of the skull by using A-mode ultrasound in computer-aided surgery (practical and clinical measurements). The accuracy tests on the human skull specimen revealed that the mean +/- SD fiducial registration error was 1.00 +/- 0.19 mm in the best series for A-mode ultrasound surface matchings and was robust with respect to different sets of surface points. The mean +/- SD root mean square error from the 12 A-mode ultrasound matchings in the patient study was 0.49 +/- 0.20 mm. A-mode ultrasound surface matching can be used as a noninvasive and accurate registration procedure in computer-aided surgery of the head.

  8. SU-E-T-300: Spatial Variations of Multiple Off-Axial Targets for a Single Isocenter SRS Treatment Plan in ExacTrac 6D Robotic Couch System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S [Genesis Medical Center, Davenport, IA (United States); Tseng, T [Mount Sinai Hospital, NY, NY (United States)

    2014-06-01

    Purpose: To evaluate the spatial variations of multiple off-axial targets for a single isocenter stereotactic radiosurgery (SRS) treatment plan in ExacTrac 6D robotic couch system (BrainLab AG). Methods: Five metallic ball bearing (BB) markers were placed sparsely in 3D off-axial locations (non-coplanar) inside a skull phantom as the representatives of multiple targets mimicking multiple brain metastases. The locations of the BB markers were carefully chosen to minimize overlapping of each other in a port imaging detector plane. The skull phantom was immobilized by a frameless mask and CT scanned with a BrainLab Head and Neck Localizer using a GE Optima MDCT scanner. The CT images were exported to iPlan software (BrainLab AG) and a multiple target PTV was drawn by combining all the contours of the BBs. The margin of the MLC opening was selected as 3 mm expansion outward. Two coplanar arc beams were placed to generate a single isocenter SRS plan to treat the PTV. The arc beams were delivered using Novalis Tx system with portal imaging acquisition mode per 10% temporal resolution. The locations of the BBs were visualized and analyzed with respect to the MLC aperture in the treatment plan similar to the Winston-Lutz test. Results: All the BBs were clearly identified inside the MLC openings. The positional errors for the BBs were overall less than 1 mm along the rotational path of the two arcs. Conclusion: This study verified that the spatial deviations of multiple off-axial targets for a single isocenter SRS treatment plan is within sub-millimeter range in ExacTrac 6D robotic couch system. Accompanied with the Winston-Lutz test, this test will quality-assure the spatial accuracies of the isocenter as well as the positions of multiple off-axial targets for the SRS treatment using a single isocenter multiple target treatment plan.

  9. SU-E-J-163: A Biomechanical Lung Model for Respiratory Motion Study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X; Belcher, AH; Grelewicz, Z; Wiersma, RD [The University of Chicago, Chicago, IL (United States)

    2015-06-15

    Purpose: This work presents a biomechanical model to investigate the complex respiratory motion for the lung tumor tracking in radiosurgery by computer simulation. Methods: The models include networked massspring-dampers to describe the tumor motion, different types of surrogate signals, and the force generated by the diaphragm. Each mass-springdamper has the same mechanical structure and each model can have different numbers of mass-spring-dampers. Both linear and nonlinear stiffness parameters were considered, and the damping ratio was tuned in a range so that the tumor motion was over-damped (no natural tumor oscillation occurs without force from the diaphragm). The simulation was run by using ODE45 (ordinary differential equations by Runge-Kutta method) in MATLAB, and all time courses of motions and inputs (force) were generated and compared. Results: The curvature of the motion time courses around their peaks was sensitive to the damping ratio. Therefore, the damping ratio can be determined based on the clinical data of a high sampling rate. The peak values of different signals and the time the peaks occurred were compared, and it was found that the diaphragm force had a time lead over the tumor motion, and the lead time (0.1–0.4 seconds) depended on the distance between the tumor and the diaphragm. Conclusion: We reported a model based analysis approach for the spatial and temporal relation between the motion of the lung tumor and the surrogate signals. Due to the phase lead of the diaphragm in comparing with the lung tumor motion, the measurement of diaphragm motion (or its electromyography signal) can be used as a beam gating signal in radiosurgery, and it can also be an additional surrogate signal for better tumor motion tracking. The research is funded by the American Cancer Society (ACS) grant. The grant name is: Frameless SRS Based on Robotic Head Motion Cancellation. The grant number is: RSG-13-313-01-CCE.

  10. A Low-Cost iPhone-Assisted Augmented Reality Solution for the Localization of Intracranial Lesions.

    Directory of Open Access Journals (Sweden)

    YuanZheng Hou

    Full Text Available Precise location of intracranial lesions before surgery is important, but occasionally difficult. Modern navigation systems are very helpful, but expensive. A low-cost solution that could locate brain lesions and their surface projections in augmented reality would be beneficial. We used an iPhone to partially achieve this goal, and evaluated its accuracy and feasibility in a clinical neurosurgery setting.We located brain lesions in 35 patients, and using an iPhone, we depicted the lesion's surface projection onto the skin of the head. To assess the accuracy of this method, we pasted computed tomography (CT markers surrounding the depicted lesion boundaries on the skin onto 15 patients. CT scans were then performed with or without contrast enhancement. The deviations (D between the CT markers and the actual lesion boundaries were measured. We found that 97.7% of the markers displayed a high accuracy level (D ≤ 5mm. In the remaining 20 patients, we compared our iPhone-based method with a frameless neuronavigation system. Four check points were chosen on the skin surrounding the depicted lesion boundaries, to assess the deviations between the two methods. The integrated offset was calculated according to the deviations at the four check points. We found that for the supratentorial lesions, the medial offset between these two methods was 2.90 mm and the maximum offset was 4.2 mm.This low-cost, image-based, iPhone-assisted, augmented reality solution is technically feasible, and helpful for the localization of some intracranial lesions, especially shallow supratentorial intracranial lesions of moderate size.

  11. CyberKnife Radiosurgery – Value as an Adjunct to Surgical Treatment of HCC?

    Science.gov (United States)

    Schoenberg, Markus; Khandoga, Andrey; Stintzing, Sebastian; Trumm, Christoph; Schiergens, Tobias Simon; Angele, Martin; op den Winkel, Mark; Werner, Jens; Rentsch, Markus

    2016-01-01

    Introduction CyberKnife radiosurgery (CK) is an effective tool for the treatment of malignancies. Its greatest potential is in high-dose radiosurgery delivered to targets in organs that move with respiration, e.g., liver tumors. For hepatocellular carcinoma (HCC), however, surgical treatment (resection, transplantation) is most likely to produce long-term survival; for non-resectable tumors, therapies other than radiosurgery are typically recommended. This study evaluated the long-lasting anti-tumor effects of CK combined with surgery in patients with HCC. Materials and methods  Eighteen patients (three women, 15 men) were included in this prospective observational study. They received 21 single-fraction CK treatments (26 Gy). Patient characteristics, treatment effects, tumor response (according to the Response Evaluation Criteria In Solid Tumors (RECIST) grading) and survival were measured for a median period of 29 months. Results Local tumor control was achieved in 15 patients, with complete and partial remission observed in 10 and five patients, respectively. One patient was treated for two separate lesions in one session, and one received three treatments each separated by two-year intervals; both patients are tumor-free. Two patients showed minimal response, and in one patient local tumor viability could not be excluded by MRI. Nine patients had HCC recurrence, all distant to the treated site. Nine patients died during follow-up, including two with clear relation to tumor progress. Tumor-free survival was 79.4% after one year and 29.8% after three years, and the corresponding overall survival was 84.8% and 66%. Conclusion  This study shows the high effectiveness of single-session frameless CyberKnife radiosurgery for treatment of hepatocellular carcinoma and reconfirms previous results of fractioned radiotherapy of HCC. It also demonstrates the potential of radiosurgery to be combined with surgical concepts. PMID:27284498

  12. SU-E-T-669: Radiosurgery Failure for Trigeminal Neuralgia: A Study of Radiographic Spatial Fidelity

    Energy Technology Data Exchange (ETDEWEB)

    Howe, J [Associates In Medical Physics, Louisville, KY (United States); Spalding, A [Norton Cancer Institute, Louisville, Kentucky (United States)

    2015-06-15

    Purpose: Management of Trigeminal Neuralgia with radiosurgery is well established, but often met with limited success. Recent advancements in imaging afford improvements in target localization for radiosurgery. Methods: A Trigeminal Neuralgia radiosurgery specific protocol was established for MR enhancement of the trigeminal nerve using a CISS scan with slice spacing of 0.7mm. Computed Tomography simulation was performed using axial slices on a 40 slice CT with slice spacing of 0.6mm. These datasets were registered using a mutual information algorithm and localized in a stereotactic coordinate system. Image registration between the MR and CT was evaluated for each patient by a Medical Physicist to ensure accuracy. The dorsal root entry zone target was defined on the CISS MR by a Neurosurgeon and dose calculations performed on the localized CT. Treatment plans were reviewed and approved by a Radiation Oncologist and Neurosurgeon. Image guided radiosurgery was delivered using positioning tolerance of 0.5mm and 1°. Eight patients with Trigeminal Neuralgia were treated with this protocol. Results: Seven patients reported a favorable response to treatment with average Barrow Neurological Index pain score of four before treatment and one following treatment. Only one patient had a BNI>1 following treatment and review of the treatment plan revealed that the CISS MR was registered to the CT via a low resolution (5mm slice spacing) T2 MR. All other patients had CISS MR registered directly with the localized CT. This patient was retreated 6 months later using direct registration between CISS MR and localized CT and subsequently responded to treatment with a BNI of one. Conclusion: Frameless radiosurgery offers an effective solution to Trigeminal Neuralgia management provided appropriate technology and imaging protocols (utilizing submillimeter imaging) are established and maintained.

  13. Contraception. Slow train gathers speed.

    Science.gov (United States)

    Hampton, N; Kubba, A

    The otherwise slow pace of contraceptive research developments has recently quickened, with new products developed, more on the way, and encouraging new data emerging about existing methods. While the 1995 UK pill scare called attention to a differential in the risk of venous thromboembolism (VTE) between pills containing levonorgestrel or norethisterone and those containing desogestrel or gestodene, there is only an extremely small level of excess mortality attributable to third-generation progestogens, less than 2 per million women per year. Tentative evidence suggests that pills with less anti-estrogenic progestogens are neutral with regard to coronary artery disease. The pill remains extremely safe for healthy young women, although additional research with larger numbers of participants is warranted. Salient research findings are that the combined oral contraceptive pill may protect against colon cancer, the pill appears to offer no protection against bone fractures, new products contain less estrogen and have a shortened pill-free interval, a WHO paper showed no significant association between cardiovascular disease and the use of oral or injectable progestogens, a UK study showed no correlation between bone density and plasma estrogen concentrations among long-term users of depot medroxyprogesterone acetate, and a WHO controlled trial found a progestogen-only method of emergency contraception to be considerably more effective in preventing expected pregnancies than the Yuzpe regimen. The T 380 copper IUD provides very high protection against intrauterine and extrauterine pregnancies for 10 years and is now available in an improved inserting mechanism, the Mirena levonorgestrel-releasing IUD system is now licensed for 5 years, and the GyneFIX IUD implant is a frameless device fixed during insertion to the fundal myometrium.

  14. Exploring the contributions of premotor and parietal cortex to spatial compatibility using image-guided TMS.

    Science.gov (United States)

    Koski, Lisa; Molnar-Szakacs, Istvan; Iacoboni, Marco

    2005-01-15

    Functional brain imaging studies have demonstrated increased activity in dorsal premotor and posterior parietal cortex when performing spatial stimulus-response compatibility tasks (SRC). We tested the specific role of these regions in stimulus-response mapping using single-pulse transcranial magnetic stimulation (TMS). Subjects were scanned using functional magnetic resonance imaging (fMRI) prior to the TMS session during performance of a task in which spatial compatibility was manipulated. For each subject, the area of increased signal within the regions of interest was registered onto their own high-resolution T1-weighted anatomic scan. TMS was applied to these areas for each subject using a frameless stereotaxic system. Task accuracy and reaction time (RT) were measured during blocks of compatible or incompatible trials and during blocks of real TMS or sham stimulation. On each trial, a single TMS pulse was delivered at 50, 100, 150, or 200 ms after the onset of the stimulus in the left or right visual field. TMS over the left premotor cortex produced various facilitatory effects, depending on the timing of the stimulation. At short intervals, TMS appeared to prime the left dorsal premotor cortex to select a right-hand response more quickly, regardless of stimulus-response compatibility. The strongest effect of stimulation, however, occurred at the 200-ms interval, when TMS facilitated left-hand responses during the incompatible condition. Facilitation of attention to the contralateral visual hemifield was observed during stimulation over the parietal locations. We conclude that the left premotor cortex is one of the cortical regions responsible for overriding automatic stimulus-response associations.

  15. Extended use of the intrauterine device: a literature review and recommendations for clinical practice.

    Science.gov (United States)

    Wu, Justine P; Pickle, Sarah

    2014-06-01

    There are multiple advantages to "extended use" of the intrauterine device (IUD) use beyond the manufacturer-approved time period, including prolongation of contraceptive and non-contraceptive benefits. We performed a literature review of studies that have reported pregnancy outcomes associated with extended use of IUDs, including copper IUDs and the levonorgestrel intrauterine system (LNG-IUS). Among parous women who are at least 25 years old at the time of IUD insertion, there is good evidence to support extended use of the following devices: the TCu380A and the TCu220 for 12 years, the Multiload Cu-375 for 10 years, the frameless GyneFix® (330 mm²) for 9 years, the levonorgestrel intrauterine system 52 mg (Mirena®) for 7 years and the Multiload Cu-250 for 4 years. Women who are at least 35 years old at the time of insertion of a TCu380A IUD can continue use until menopause with a negligible risk of pregnancy. We found no data to support use of the LNG-IUS 13.5 mg (Skyla®) beyond 3 years. When counseling about extended IUD use, clinicians should consider patient characteristics and preferences, as well as country- and community-specific factors. Future research is necessary to determine the risk of pregnancy associated with extended use of the copper IUD and the LNG-IUS among nulliparous women and women less than 25 years old at the time of IUD insertion. More data are needed on the potential effect of overweight and obesity on the long-term efficacy of the LNG-IUS.

  16. Intraoperative magnetic resonance imaging.

    Science.gov (United States)

    Hall, Walter A; Truwit, Charles L

    2011-01-01

    Neurosurgeons have become reliant on image-guidance to perform safe and successful surgery both time-efficiently and cost-effectively. Neuronavigation typically involves either rigid (frame-based) or skull-mounted (frameless) stereotactic guidance derived from computed tomography (CT) or magnetic resonance imaging (MRI) that is obtained days or immediately before the planned surgical procedure. These systems do not accommodate for brain shift that is unavoidable once the cranium is opened and cerebrospinal fluid is lost. Intraoperative MRI (ioMRI) systems ranging in strength from 0.12 to 3 Tesla (T) have been developed in part because they afford neurosurgeons the opportunity to accommodate for brain shift during surgery. Other distinct advantages of ioMRI include the excellent soft tissue discrimination, the ability to view the surgical site in three dimensions, and the ability to "see" tumor beyond the surface visualization of the surgeon's eye, either with or without a surgical microscope. The enhanced ability to view the tumor being biopsied or resected allows the surgeon to choose a safe surgical corridor that avoids critical structures, maximizes the extent of the tumor resection, and confirms that an intraoperative hemorrhage has not resulted from surgery. Although all ioMRI systems allow for basic T1- and T2-weighted imaging, only high-field (>1.5 T) MRI systems are capable of MR spectroscopy (MRS), MR angiography (MRA), MR venography (MRV), diffusion-weighted imaging (DWI), and brain activation studies. By identifying vascular structures with MRA and MRV, it may be possible to prevent their inadvertent injury during surgery. Biopsying those areas of elevated phosphocholine on MRS may improve the diagnostic yield for brain biopsy. Mapping out eloquent brain function may influence the surgical path to a tumor being resected or biopsied. The optimal field strength for an ioMRI-guided surgical system and the best configuration for that system are as yet

  17. Non-invasive Transcranial Magnetic Stimulation (TMS of the Motor Cortex for Neuropathic Pain—At the Tipping Point?

    Directory of Open Access Journals (Sweden)

    Roi Treister

    2013-10-01

    Full Text Available The term “neuropathic pain” (NP refers to chronic pain caused by illnesses or injuries that damage peripheral or central pain-sensing neural pathways to cause them to fire inappropriately and signal pain without cause. Neuropathic pain is common, complicating diabetes, shingles, HIV, and cancer. Medications are often ineffective or cause various adverse effects, so better approaches are needed. Half a century ago, electrical stimulation of specific brain regions (neuromodulation was demonstrated to relieve refractory NP without distant effects, but the need for surgical electrode implantation limited use of deep brain stimulation. Next, electrodes applied to the dura outside the brain’s surface to stimulate the motor cortex were shown to relieve NP less invasively. Now, electromagnetic induction permits cortical neurons to be stimulated entirely non-invasively using transcranial magnetic stimulation (TMS. Repeated sessions of many TMS pulses (rTMS can trigger neuronal plasticity to produce long-lasting therapeutic benefit. Repeated TMS already has US and European regulatory approval for treating refractory depression, and multiple small studies report efficacy for neuropathic pain. Recent improvements include “frameless stereotactic” neuronavigation systems, in which patients’ head MRIs allow TMS to be applied to precise underlying cortical targets, minimizing variability between sessions and patients, which may enhance efficacy. Transcranial magnetic stimulation appears poised for the larger trials necessary for regulatory approval of a NP indication. Since few clinicians are familiar with TMS, we review its theoretical basis and historical development, summarize the neuropathic pain trial results, and identify issues to resolve before large-scale clinical trials.

  18. Accuracy evaluation of the optical surface monitoring system on EDGE linear accelerator in a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Fogliata, Antonella, E-mail: Antonella.Fogliata@humanitas.it; Stravato, Antonella; Tomatis, Stefano; Cozzi, Luca; Scorsetti, Marta

    2016-07-01

    Frameless stereotactic radiosurgery (SRS) requires dedicated systems to monitor the patient position during the treatment to avoid target underdosage due to involuntary shift. The optical surface monitoring system (OSMS) is here evaluated in a phantom-based study. The new EDGE linear accelerator from Varian (Varian, Palo Alto, CA) integrates, for cranial lesions, the common cone beam computed tomography (CBCT) and kV-MV portal images to the optical surface monitoring system (OSMS), a device able to detect real-time patient's face movements in all 6 couch axes (vertical, longitudinal, lateral, rotation along the vertical axis, pitch, and roll). We have evaluated the OSMS imaging capability in checking the phantoms' position and monitoring its motion. With this aim, a home-made cranial phantom was developed to evaluate the OSMS accuracy in 4 different experiments: (1) comparison with CBCT in isocenter location, (2) capability to recognize predefined shifts up to 2° or 3 cm, (3) evaluation at different couch angles, (4) ability to properly reconstruct the surface when the linac gantry visually block one of the cameras. The OSMS system showed, with a phantom, to be accurate for positioning in respect to the CBCT imaging system with differences of 0.6 ± 0.3 mm for linear vector displacement, with a maximum rotational inaccuracy of 0.3°. OSMS presented an accuracy of 0.3 mm for displacement up to 1 cm and 1°, and 0.5 mm for larger displacements. Different couch angles (45° and 90°) induced a mean vector uncertainty < 0.4 mm. Coverage of 1 camera produced an uncertainty < 0.5 mm. Translations and rotations of a phantom can be accurately detect with the optical surface detector system.

  19. Screw Placement Accuracy and Outcomes Following O-Arm-Navigated Atlantoaxial Fusion: A Feasibility Study.

    Science.gov (United States)

    Smith, Jacob D; Jack, Megan M; Harn, Nicholas R; Bertsch, Judson R; Arnold, Paul M

    2016-06-01

    Study Design Case series of seven patients. Objective C2 stabilization can be challenging due to the complex anatomy of the upper cervical vertebrae. We describe seven cases of C1-C2 fusion using intraoperative navigation to aid in the screw placement at the atlantoaxial (C1-C2) junction. Methods Between 2011 and 2014, seven patients underwent posterior atlantoaxial fusion using intraoperative frameless stereotactic O-arm Surgical Imaging and StealthStation Surgical Navigation System (Medtronic, Inc., Minneapolis, Minnesota, United States). Outcome measures included screw accuracy, neurologic status, radiation dosing, and surgical complications. Results Four patients had fusion at C1-C2 only, and in the remaining three, fixation extended down to C3 due to anatomical considerations for screw placement recognized on intraoperative imaging. Out of 30 screws placed, all demonstrated minimal divergence from desired placement in either C1 lateral mass, C2 pedicle, or C3 lateral mass. No neurovascular compromise was seen following the use of intraoperative guided screw placement. The average radiation dosing due to intraoperative imaging was 39.0 mGy. All patients were followed for a minimum of 12 months. All patients went on to solid fusion. Conclusion C1-C2 fusion using computed tomography-guided navigation is a safe and effective way to treat atlantoaxial instability. Intraoperative neuronavigation allows for high accuracy of screw placement, limits complications by sparing injury to the critical structures in the upper cervical spine, and can help surgeons make intraoperative decisions regarding complex pathology.

  20. A Palestinian State - Yes or No? Constructing political discourse in the Israeli print news media - An experimental design

    Directory of Open Access Journals (Sweden)

    Samuel Peleg

    2005-10-01

    Full Text Available This paper describes a research project which examines how attitudes are shaped and formed and how opinion makers and agenda setters influence such attitudes in their followers. We concentrate on the written media as our research environment. We explore how framing of news items affect readers. Our research design creates three articles which describe an identical topic: the ratification of a Palestinian state by the Israeli Cabinet. The three articles are framed differently: one advocates the decision and thus is imbued with positive framing, the second condemns it, and accordingly is permeated by negative frames and the third is frameless. Three different reader groups grapple with the texts and are being tested with the same three tests: memory, categorization and meaning tests. We predict that people who read the pro-state text would respond favorably to the idea of a Palestinian state, whereas those who were exposed to the opposite framing would develop an adverse attitude. In sum, the interaction between leaders and followers is extremely important in shaping attitudes such as adherence, loyalty and commitment. Leaders with established authority and command have the potential of molding and forging beliefs, judgments and evaluations. Our results demonstrate significant support for this claim. This research might have long-range implications beyond indicating the nexus between manipulating a text and the comprehension of its readers. The suggestions and conclusions elaborated here can be incorporated into a broader research agenda, which deals with issues such as: authority and legitimacy (how do leaders lead, why do adherents follow?, recruitment and mobilization (how to animate and stimulate crowds?, political activism (how to elicit loyalty, commitment and willing to sacrifice?, propaganda and incitement (how to sway opinions and positions?, and from there, to even larger scaled explorations into the political, psychological and

  1. Contraception - Update and Trends

    Directory of Open Access Journals (Sweden)

    Rabe T

    2007-01-01

    Full Text Available In the future, fertility control will focus on the improvement of existing methods (efficacy, side effects, easy use, duration of action, manufacturing process, costs, on new approaches (mode of action and on new targets for contraception. Counselling of women in view of contraceptive choices based on individual risks (e. g. cardiovascular disease, thrombophilia, family risk of breast cancer, sexually transmitted diseases will gain more and more importance. Only a few companies can afford research in contraception such as Bayer-Schering-Pharma, Wyeth-Ayerst, Ortho-McNeil and Organon. Female contraception: Ovulation inhibition: In the future, a focus will be placed on the preselection of patients to minimize their individual risk, new oral contraceptive (OC regimen, OC with new progestins, OC with estradiol or estradiolesters, new ovulation inhibitors with new progestins and new regimens including long cycles and continuous steroidal contraceptives, new contraceptive patches, vaginal rings, spray-on contraceptives, recently identified genes involved in the ovulation process as new targets for ovulation inhibitors. Fertilisation inhibition: New intrauterine systems will comprise: a smaller Mirena intrauterine system releasing levonorgestrel (LNG and new frameless progestin-releasing intrauterine systems (IUS. Various new contraceptive barriers have been introduced. Research is ongoing on substances acting both as spermicides and as microbicides, reducing the risk of sexually transmitted diseases. New implantables and injectables will feature an improved pharmacokinetic profile, decreased side effects and a safer delivery system. Additionally, there are various new approaches in female sterilisation. Immunocontraception for the female will not be available in the near future. Implantation inhibition: Selective progesterone receptor modulators (SPRMs are tested for postcoital contraception. New targets are analysed for immunocontraceptives. Male

  2. The cortex-based alignment approach to TMS coil positioning.

    Science.gov (United States)

    Duecker, Felix; Frost, Martin A; de Graaf, Tom A; Graewe, Britta; Jacobs, Christianne; Goebel, Rainer; Sack, Alexander T

    2014-10-01

    TMS allows noninvasive manipulation of brain activity in healthy participants and patients. The effectiveness of TMS experiments critically depends on precise TMS coil positioning, which is best for most brain areas when a frameless stereotactic system is used to target activation foci based on individual fMRI data. From a purely scientific perspective, individual fMRI-guided TMS is thus the method of choice to ensure optimal TMS efficiency. Yet, from a more practical perspective, such individual functional data are not always available, and therefore alternative TMS coil positioning approaches are often applied, for example, based on functional group data reported in Talairach coordinates. We here propose a novel method for TMS coil positioning that is based on functional group data, yet only requires individual anatomical data. We used cortex-based alignment (CBA) to transform individual anatomical data to an atlas brain that includes probabilistic group maps of two functional regions (FEF and hMT+/V5). Then, these functional group maps were back-transformed to the individual brain anatomy, preserving functional-anatomical correspondence. As a proof of principle, the resulting CBA-based functional targets in individual brain space were compared with individual FEF and hMT+/V5 hotspots as conventionally localized with individual fMRI data and with targets based on Talairach coordinates as commonly done in TMS research in case only individual anatomical data are available. The CBA-based approach significantly improved localization of functional brain areas compared with traditional Talairach-based targeting. Given the widespread availability of CBA schemes and preexisting functional group data, the proposed procedure is easy to implement and at no additional measurement costs. However, the accuracy of individual fMRI-guided TMS remains unparalleled, and the CBA-based approach should only be the method of choice when individual functional data cannot be obtained or

  3. Five Fraction Image-Guided Radiosurgery for Primary and Recurrent Meningiomas

    Directory of Open Access Journals (Sweden)

    Eric Karl Oermann

    2013-08-01

    Full Text Available Purpose: Benign tumors that arise from the meninges can be difficult to treat due to their potentially large size and proximity to critical structures such as cranial nerves and sinuses. Single fraction radiosurgery may increase the risk of symptomatic peritumoral edema. In this study, we report our results on the efficacy and safety of five fraction image-guided radiosurgery for benign meningiomas. Materials/Methods: Clinical and radiographic data from 38 patients treated with five fraction radiosurgery were reviewed retrospectively. Mean tumor volume was 3.83mm3 (range, 1.08-20.79 mm3. Radiation was delivered using the CyberKnife, a frameless robotic image-guided radiosurgery system with a median total dose of 25 Gy (range, 25 Gy-35 Gy. Results: The median follow-up was 20 months. Acute toxicity was minimal with eight patients (21% requiring a short course of steroids for headache at the end of treatment. Pre-treatment neurological symptoms were present in 24 patients (63.2%. Post treatment, neurological symptoms resolved completely in 14 patients (58.3%, and were persistent in eight patients (33.3%. There were no local failures, 24 tumors remained stable (64% and 14 regressed (36%. Pre-treatment peritumoral edema was observed in five patients (13.2%. Post-treatment asymptomatic peritumoral edema developed in five additional patients (13.2%. On multivariate analysis, pre-treatment peritumoral edema and location adjacent to a large vein were significant risk factors for radiographic post-treatment edema (p = 0.001 and p = 0.026 respectively. Conclusions: These results suggest that five fraction image-guided radiosurgery is well tolerated with a response rate for neurologic symptoms that is similar to other standard treatment options. Rates of peritumoral edema and new cranial nerve deficits following five fraction radiosurgery were low. Longer follow-up is required to validate the safety and long-term effectiveness of this treatment approach.

  4. Hypofractionated stereotactic radiotherapy for brain metastases from lung cancer. Evaluation of indications and predictors of local control

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Takeaki [Kobe University Graduate School of Medicine, Division of Radiation Oncology, Hyogo (Japan); Seirei Mikatahara General Hospital, Department of Radiation Oncology, Shizuoka (Japan); Yamada, Kazunari; Isogai, Kenta; Tonosaki, Yoshihiro [Seirei Mikatahara General Hospital, Department of Radiation Oncology, Shizuoka (Japan); Harada, Aya [Kobe Minimum Invasive Cancer Medical Center, Department of Radiation Oncology, Hyogo (Japan); Demizu, Yusuke [Hyogo Ion Beam Medical Center, Department of Radiology, Hyogo (Japan); Miyawaki, Daisuke; Yoshida, Kenji; Ejima, Yasuo; Sasaki, Ryohei [Kobe University Graduate School of Medicine, Division of Radiation Oncology, Hyogo (Japan)

    2016-06-15

    To evaluate the efficacy and toxicity of hypofractionated stereotactic radiotherapy (HSRT) for brain metastases (BMs) from lung cancer, and to explore prognostic factors associated with local control (LC) and indication. We evaluated patients who were treated with linac-based HSRT for BMs from lung cancer. Lesions treated with stereotactic radiosurgery (SRS) in the same patients during the same periods were analysed and compared with HSRT in terms of LC or toxicity. There were 53 patients with 214 lesions selected for this analysis (HSRT: 76 lesions, SRS: 138 lesions). For HSRT, the median prescribed dose was 35 Gy in 5 fractions. The 1-year LC rate was 83.6 % in HSRT; on multivariate analysis, a planning target volume (PTV) of <4 cm{sup 3}, biologically effective dose (BED{sub 10}) of ≥51 Gy, and adenocarcinoma were significantly associated with better LC. Moreover, in PTVs ≥ 4 cm{sup 3}, there was a significant difference in LC between BED{sub 10} < 51 Gy and ≥ 51 Gy (p = 0.024). On the other hand, in PTVs < 4 cm{sup 3}, both HSRT and SRS had good LC with no significant difference (p = 0.195). Radiation necrosis emerged in 5 of 76 lesions (6.6 %) treated with HSRT and 21 of 138 (15.2 %) lesions treated with SRS (p = 0.064). Linac-based HSRT was safe and effective for BMs from lung cancer, and hence might be particularly useful in or near an eloquent area. PTV, BED{sub 10}, and pathological type were significant prognostic factors. Furthermore, in BMs ≥ 4 cm{sup 3}, a dose of BED ≥ 51 Gy should be considered. (orig.) [German] Beurteilung von Wirksamkeit und Toxizitaet einer hypofraktionierten stereotaktischen Strahlentherapie (HSRT) zur Behandlung von Hirnmetastasen (HM) eines Lungenkarzinoms und Erforschung von mit der lokalen Kontrolle (LK) und der Indikation assoziierten Prognosefaktoren. Analysiert wurden Daten von Patienten (n = 53), die sich einer Linearbeschleuniger-basierten HSRT unterzogen (mit HSRT behandelte Laesionen n = 76; Median der

  5. Quality of Intensity Modulated Radiation Therapy Treatment Plans Using a {sup 60}Co Magnetic Resonance Image Guidance Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, H. Omar, E-mail: hwooten@radonc.wustl.edu; Green, Olga; Yang, Min; DeWees, Todd; Kashani, Rojano; Olsen, Jeff; Michalski, Jeff; Yang, Deshan; Tanderup, Kari; Hu, Yanle; Li, H. Harold; Mutic, Sasa

    2015-07-15

    Purpose: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating {sup 60}Co intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. Methods and Materials: The ViewRay treatment planning system (Oakwood Village, OH) was used to create {sup 60}Co IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The {sup 60}Co and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. Results: All {sup 60}Co IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for {sup 60}Co was within <1% and 3% of linac plans for 100% and 95% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range <20 Gy, but comparable sparing for organs with mean doses >20 Gy. The mean doses for all {sup 60}Co plan OARs were within clinical tolerances. Conclusions: A commercial {sup 60}Co MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system.

  6. Conditions for coherent-synchrotron-radiation-induced microbunching suppression in multibend beam transport or recirculation arcs

    Science.gov (United States)

    Tsai, C.-Y.; Di Mitri, S.; Douglas, D.; Li, R.; Tennant, C.

    2017-02-01

    The coherent synchrotron radiation (CSR) of a high-brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in beam phase space degradation. On one hand, CSR can perturb electron transverse motion in dispersive regions along the beam line and possibly cause emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching instability. For transport arcs, several schemes have been proposed to suppress the CSR-induced emittance growth. Correspondingly, a few scenarios have been introduced to suppress CSR-induced microbunching instability, which however mostly aim for linac-based machines. In this paper we provide sufficient conditions for suppression of CSR-induced microbunching instability along transport or recirculation arcs. Examples are presented with the relevant microbunching analyses carried out by our developed semianalytical Vlasov solver [C.-Y. Tsai, D. Douglas, R. Li, and C. Tennant, Linear microbunching analysis for recirculation machines, Phys. Rev. ST Accel. Beams 19, 114401 (2016), 10.1103/PhysRevAccelBeams.19.114401]. The example lattices include low-energy (˜100 MeV ) and high-energy (˜1 GeV ) recirculation arcs, and medium-energy compressor arcs. Our studies show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. Beam current dependences of maximal CSR microbunching gains are also demonstrated, which should help outline a beam line design for different scales of nominal currents. We expect this analysis can shed light on the lattice design approach that aims to control the CSR-induced microbunching.

  7. Clinical outcome of fiducial-less CyberKnife radiosurgery for stage I non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Jung, In Hye; Song, Si Yeol; Cho, Byung Chul; Kwak, Jung Won; Jung, Nuri Hyun; Kim, Su Ssan; Choi, Eun Kyung [Dept. of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jung, Jin Hong [Dept. of Radiation Oncology, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul (Korea, Republic of); Je, Hyoung Uk [Dept. of Radiation Oncology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of); Choi, Won Sik [Dept. of Radiation Oncology, Gangneung Asan Hospital, Uiversity of Ulsan College of Medicine, Gangneung (Korea, Republic of)

    2015-06-15

    To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS). From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21. The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression. The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication.

  8. Linear Accelerator-Based Radiosurgery Alone for Arteriovenous Malformation: More Than 12 Years of Observation

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, Takayuki, E-mail: takayuki@nagasaki-u.ac.jp; Kamada, Kensaku; Izumo, Tsuyoshi; Hayashi, Nobuyuki; Nagata, Izumi

    2014-07-01

    Purpose: Although radiosurgery is an accepted treatment method for intracranial arteriovenous malformations (AVMs), its long-term therapeutic effects have not been sufficiently evaluated, and many reports of long-term observations are from gamma-knife facilities. Furthermore, there are few reported results of treatment using only linear accelerator (LINAC)-based radiosurgery (LBRS). Methods and Materials: Over a period of more than 12 years, we followed the long-term results of LBRS treatment performed in 51 AVM patients. Results: The actuarial obliteration rates, after a single radiosurgery session, at 3, 5, 10, and 15 years were 46.9%, 54.0%, 64.4%, and 68.0%, respectively; when subsequent radiosurgeries were included, the rates were 46.9%, 61.3%, 74.2%, and 90.3%, respectively. Obliteration rates were significantly related to target volumes ≥4 cm{sup 3}, marginal doses ≥12 Gy, Spetzler-Martin grades (1 vs other), and AVM scores ≥1.5; multivariate analyses revealed a significant difference for target volumes ≥4 cm{sup 3}. The postprocedural actuarial symptomatic radiation injury rates, after a single radiation surgery session, at 5, 10, and 15 years were 12.3%, 16.8%, and 19.1%, respectively. Volumes ≥4 cm{sup 3}, location (lobular or other), AVM scores ≥1.5, and the number of radiosurgery were related to radiation injury incidence; multivariate analyses revealed significant differences associated with volumes ≥4 cm{sup 3} and location (lobular or other). Conclusions: Positive results can be obtained with LBRS when performed with a target volume ≤4 cm{sup 3}, an AVM score ≤1.5, and ≥12 Gy radiation. Bleeding and radiation injuries may appear even 10 years after treatment, necessitating long-term observation.

  9. Conditions for coherent-synchrotron-radiation-induced microbunching suppression in multibend beam transport or recirculation arcs

    Directory of Open Access Journals (Sweden)

    C.-Y. Tsai

    2017-02-01

    Full Text Available The coherent synchrotron radiation (CSR of a high-brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in beam phase space degradation. On one hand, CSR can perturb electron transverse motion in dispersive regions along the beam line and possibly cause emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching instability. For transport arcs, several schemes have been proposed to suppress the CSR-induced emittance growth. Correspondingly, a few scenarios have been introduced to suppress CSR-induced microbunching instability, which however mostly aim for linac-based machines. In this paper we provide sufficient conditions for suppression of CSR-induced microbunching instability along transport or recirculation arcs. Examples are presented with the relevant microbunching analyses carried out by our developed semianalytical Vlasov solver [C.-Y. Tsai, D. Douglas, R. Li, and C. Tennant, Linear microbunching analysis for recirculation machines, Phys. Rev. ST Accel. Beams 19, 114401 (2016PRABFM1098-440210.1103/PhysRevAccelBeams.19.114401]. The example lattices include low-energy (∼100  MeV and high-energy (∼1  GeV recirculation arcs, and medium-energy compressor arcs. Our studies show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. Beam current dependences of maximal CSR microbunching gains are also demonstrated, which should help outline a beam line design for different scales of nominal currents. We expect this analysis can shed light on the lattice design approach that aims to control the CSR-induced microbunching.

  10. Noninvasive referencing of intraocular tumors for external beam radiation therapy using optical coherence tomography: A proof of concept

    Energy Technology Data Exchange (ETDEWEB)

    Rüegsegger, Michael B.; Steiner, Patrick; Kowal, Jens H., E-mail: jens.kowal@artorg.unibe.ch [ARTORG Center for Biomedical Engineering Research, University of Bern, Bern 3010 (Switzerland); Geiser, Dominik [Berne University of Applied Sciences, HuCE OptoLab, 2501 (Switzerland); Pica, Alessia; Aebersold, Daniel M. [Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Bern 3010 (Switzerland)

    2014-08-15

    Purpose: External beam radiation therapy is currently considered the most common treatment modality for intraocular tumors. Localization of the tumor and efficient compensation of tumor misalignment with respect to the radiation beam are crucial. According to the state of the art procedure, localization of the target volume is indirectly performed by the invasive surgical implantation of radiopaque clips or is limited to positioning the head using stereoscopic radiographies. This work represents a proof-of-concept for direct and noninvasive tumor referencing based on anterior eye topography acquired using optical coherence tomography (OCT). Methods: A prototype of a head-mounted device has been developed for automatic monitoring of tumor position and orientation in the isocentric reference frame for LINAC based treatment of intraocular tumors. Noninvasive tumor referencing is performed with six degrees of freedom based on anterior eye topography acquired using OCT and registration of a statistical eye model. The proposed prototype was tested based on enucleated pig eyes and registration accuracy was measured by comparison of the resulting transformation with tilt and torsion angles manually induced using a custom-made test bench. Results: Validation based on 12 enucleated pig eyes revealed an overall average registration error of 0.26 ± 0.08° in 87 ± 0.7 ms for tilting and 0.52 ± 0.03° in 94 ± 1.4 ms for torsion. Furthermore, dependency of sampling density on mean registration error was quantitatively assessed. Conclusions: The tumor referencing method presented in combination with the statistical eye model introduced in the past has the potential to enable noninvasive treatment and may improve quality, efficacy, and flexibility of external beam radiotherapy of intraocular tumors.

  11. SU-E-T-449: Hippocampal Sparing Radiotherapy Using Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Moon, S [Korea University, Seoul (Korea, Republic of); Kyung Hee University Hospital at Gangdong, Gangdong-gu (Korea, Republic of); Kim, D; Chung, W [Kyung Hee University Hospital at Gangdong, Gangdong-gu (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: The hippocampus sparing during the cranial irradiation has become interesting because it may mitigate radiation-induced neurocognitive toxicity. Herein we report our preliminary study for sparing the hippocampus with and without tilling condition for patient with brain metastases. Methods: Ten patients previously treated with whole brain were reviewed. Five patients tilted the head to around 30 degrees and others were treated without tilting. Treatment plans of linear accelerator (Linac)-based volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) were generated for prescription dose of 30 Gy in 15 fractions. Hippocampal avoidance regions were created with 5-mm volumetric expansion around the hippocampus. Whole brain, hippocampus and hippocampal avoidance volume were 1372cm3, 6cm3 and 30cm3 and hippocampal avoidance volume was 2.2% of the whole brain planned target volume in average. Organs at risk (OARs) are hippocampus, eyes, lens, and cochleae. Coverage index (CVI), conformity index (CI), homogeneity index (HI) and mean dose to OARs were used to compare dose characteristic of tilted and non-tilted cases. Results: In IMRT, when CI, CVI and HI of whole brain were 0.88, 0.09 and 0.98 in both tilted and non-tilted cases, absorbed dose of hippocampal avoidance volume in tilted cases were 10% lower than non-tilted cases. Doses in other OARs such as eyes, lens, and cochleae were also decreased about 20% when tilting the head. When CI, HI and CVI in VMAT were 0.9, 0.08 and 0.99, the dose-decreased ratio of OARs in both with and without tilting cases were almost the same with IMRT. But absolute dose of hippocampal avoidance volume in VMAT was 30% lower than IMRT. Conclusion: This study confirms that dose to hippocampus decreases if patients tilt the head. When treating the whole brain with head tilted, patients can acquire the same successful treatment Result and also preserve their valuable memory.

  12. Bowel sparing in pediatric cranio-spinal radiotherapy: a comparison of combined electron and photon and helical TomoTherapy techniques to a standard photon method

    Energy Technology Data Exchange (ETDEWEB)

    Harron, Elizabeth, E-mail: elizabeth.harron@nuh.nhs.uk [Regional Medical Physics Department, Freeman Hospital, Freeman Road, Newcastle upon Tyne (United Kingdom); Lewis, Joanne [Northern Centre for Cancer Care, Freeman Hospital, Freeman Road, Newcastle upon Tyne (United Kingdom)

    2012-07-01

    The aim of this study was to compare the dose to organs at risk (OARs) from different craniospinal radiotherapy treatment approaches available at the Northern Centre for Cancer Care (NCCC), with a particular emphasis on sparing the bowel. Method: Treatment plans were produced for a pediatric medulloblastoma patient with inflammatory bowel disease using 3D conformal 6-MV photons (3DCP), combined 3D 6-MV photons and 18-MeV electrons (3DPE), and helical photon TomoTherapy (HT). The 3DPE plan was a modification of the standard 3DCP technique, using electrons to treat the spine inferior to the level of the diaphragm. The plans were compared in terms of the dose-volume data to OARs and the nontumor integral dose. Results: The 3DPE plan was found to give the lowest dose to the bowel and the lowest nontumor integral dose of the 3 techniques. However, the coverage of the spine planning target volume (PTV) was least homogeneous using this technique, with only 74.6% of the PTV covered by 95% of the prescribed dose. HT was able to achieve the best coverage of the PTVs (99.0% of the whole-brain PTV and 93.1% of the spine PTV received 95% of the prescribed dose), but delivered a significantly higher integral dose. HT was able to spare the heart, thyroid, and eyes better than the linac-based techniques, but other OARs received a higher dose. Conclusions: Use of electrons was the best method for reducing the dose to the bowel and the integral dose, at the expense of compromised spine PTV coverage. For some patients, HT may be a viable method of improving dose homogeneity and reducing selected OAR doses.

  13. Hypofractionated stereotactic radiotherapy for low grade glioma at McGill University: long-term follow-up.

    Science.gov (United States)

    Roberge, D; Souhami, L; Olivier, A; Leblanc, R; Podgorsak, E

    2006-02-01

    Small, well-defined, unresectable low-grade gliomas are attractive targets for stereotactic irradiation. Fractionated stereotactic irradiation of these targets has the theoretical benefit of increased normal tissue sparing beyond that provided by the physical characteristics of stereotactic radiosurgery. From July 1987 to November 1992, 21 patients were treated for low-grade glioma at our institution using a hypofractionated regimen of stereotactic radiotherapy. All patients had well-circumscribed, < 40 mm tumors. No patient had had prior radiotherapy. All lesions were histologically proven WHO grade I or II glial tumors. Lesions involved sensitive brain structures and were deemed unresectable. A typical dose of 42 Gy was delivered in 6 fractions over a two-week period using rigid immobilization and a linac-based dynamic stereotactic radiosurgical technique. Patients had a median age of 23 years (9-74) and were predominantly female (60%). Median tumor diameter was 20 mm. With a median follow-up for living patients of 13.3 years, the actuarial 5, 10, and 15-year overall survival rates are 76%, 71%, and 63%, respectively. Treatment was acutely well tolerated although three patients experienced late post-therapy complications. Our results and those of 241 patients treated in nine other institutional series are reviewed. Despite some examples of favorable short-term outcomes, all reported series are highly selected and thus likely biased. The data regarding the use of SRS is limited and, in our opinion, insufficient to claim a clear therapeutic advantage to SRS in the initial management of low-grade glioma. Our own results with hypofractionated stereotactic radiotherapy are similar to those expected with standard therapy.

  14. The solenoidal transport option: IFE drivers, near term research facilities, and beam dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.P. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Briggs, R.J. [Science Applications International Corp., Pleasanton, CA (United States)

    1997-09-01

    Solenoidal magnets have been used as the beam transport system in all the high current electron induction accelerators that have been built in the past several decades. They have also been considered for the front end transport system for heavy ion accelerators for Inertial Fusion Energy (IFE) drivers, but this option has received very little attention in recent years. The analysis reported here was stimulated mainly by the recent effort to define an affordable {open_quotes}Integrated Research Experiment{close_quotes} (IRE) that can meet the near term needs of the IFE program. The 1996 FESAC IFE review panel agreed that an integrated experiment is needed to fully resolve IFE heavy ion driver science and technology issues; specifically, {open_quotes}the basic beam dynamics issues in the accelerator, the final focusing and transport issues in a reactor-relevant beam parameter regime, and the target heating phenomenology{close_quotes}. The development of concepts that can meet these technical objectives and still stay within the severe cost constraints all new fusion proposals will encounter is a formidable challenge. Solenoidal transport has a very favorable scaling as the particle mass is decreased (the main reason why it is preferred for electrons in the region below 50 MeV). This was recognized in a recent conceptual study of high intensity induction linac-based proton accelerators for Accelerator Driven Transmutation Technologies, where solenoidal transport was chosen for the front end. Reducing the ion mass is an obvious scaling to exploit in an IRE design, since the output beam voltage will necessarily be much lower than that of a full scale driver, so solenoids should certainly be considered as one option for this experiment as well.

  15. Practical and clinical considerations in Cobalt-60 tomotherapy

    Directory of Open Access Journals (Sweden)

    Joshi Chandra

    2009-01-01

    Full Text Available Cobalt-60 (Co-60 based radiation therapy continues to play a significant role in not only developing countries, where access to radiation therapy is extremely limited, but also in industrialized countries. Howver, technology has to be developed to accommodate modern techniques, in-clud-ing image guided and adaptive radiation therapy (IGART. In this paper we describe some of the practical and clinical considerations for Co-60 based tomotherapy by comparing Co-60 and 6 MV linac-based tomotherapy plans for a head and neck (HandN cancer and a prostate cancer case. The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX. The EGSnrc/BEAMnrc Monte Carlo (MC code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data. An in-house inverse treatment planning program was then used to generate optimized tomotherapy dose distributions for the H and N and prostate cases. The dose distributions, cumulative dose area histograms (DAHs and dose difference maps were used to evaluate and compare Co-60 and 6 MV based tomotherapy plans. A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes and OARs (spinal cord in HandN case, and rectum in prostate case.

  16. The influence of field size on stopping-power ratios in- and out-of-field: quantitative data for the BrainLAB m3 micro-multileaf collimator.

    Science.gov (United States)

    Taylor, Michael; Kairn, Tanya; Kron, Tomas; Dunn, Leon; Johnston, Peter N; Franich, Rick D

    2012-11-08

    The objective of this work is to quantify the systematic errors introduced by the common assumption of invariant secondary electron spectra with changing field sizes, as relevant to stereotactic radiotherapy and other treatment modes incorporating small beam segments delivered with a linac-based stereotactic unit. The EGSnrc/BEAMnrc Monte Carlo radiation transport code was used to construct a dosimetrically-matched model of a Varian 600C linear accelerator with mounted BrainLAB micro-multileaf collimator. Stopping-power ratios were calculated for field sizes ranging from 6 × 6 mm2 up to the maximum (98 × 98 mm2), and differences between these and the reference field were computed. Quantitative stopping power data for the BrainLAB micro-multileaf collimator has been compiled. Field size dependent differences to reference conditions increase with decreasing field size and increasing depth, but remain a fraction of a percent for all field sizes studied. However, for dosimetry outside the primary field, errors induced by the assumption of invariant electron spectra can be greater than 1%, increasing with field size. It is also shown that simplification of the Spencer-Attix formulation by ignoring secondary electrons below the cutoff kinetic energy applied to the integration results in underestimation of stopping-power ratios of about 0.3% (and is independent of field size and depth). This work is the first to quantify stopping powers from a BrainLAB micro-multileaf collimator. Many earlier studies model simplified beams, ignoring collimator scatter, which is shown to significantly influence the spectrum. Importantly, we have confirmed that the assumption of unchanging electron spectra with varying field sizes is justifiable when performing (typical) in-field dosimetry of stereotactic fields. Clinicians and physicists undertaking precise out-of-field measurements for the purposes of risk estimation, ought to be aware that the more pronounced spectral variation results

  17. Stem cell transplantation strategies for the restoration of cognitive dysfunction caused by cranial radiotherapy.

    Science.gov (United States)

    Acharya, Munjal M; Roa, Dante E; Bosch, Omar; Lan, Mary L; Limoli, Charles L

    2011-10-18

    Radiotherapy often provides the only clinical recourse for those afflicted with primary or metastatic brain tumors. While beneficial, cranial irradiation can induce a progressive and debilitating decline in cognition that may, in part, be caused by the depletion of neural stem cells. Given the increased survival of patients diagnosed with brain cancer, quality of life in terms of cognitive health has become an increasing concern, especially in the absence of any satisfactory long-term treatments. To address this serious health concern we have used stem cell replacement as a strategy to combat radiation-induced cognitive decline. Our model utilizes athymic nude rats subjected to cranial irradiation. The ionizing radiation is delivered as either whole brain or as a highly focused beam to the hippocampus via linear accelerator (LINAC) based stereotaxic radiosurgery. Two days following irradiation, human neural stem cells (hNSCs) were stereotaxically transplanted into the hippocampus. Rats were then assessed for changes in cognition, grafted cell survival and for the expression of differentiation-specific markers 1 and 4-months after irradiation. Our cognitive testing paradigms have demonstrated that animals engrafted with hNSCs exhibit significant improvements in cognitive function. Unbiased stereology reveals significant survival (10-40%) of the engrafted cells at 1 and 4-months after transplantation, dependent on the amount and type of cells grafted. Engrafted cells migrate extensively, differentiate along glial and neuronal lineages, and express a range of immature and mature phenotypic markers. Our data demonstrate direct cognitive benefits derived from engrafted human stem cells, suggesting that this procedure may one day afford a promising strategy for the long-term functional restoration of cognition in individuals subjected to cranial radiotherapy. To promote the dissemination of the critical procedures necessary to replicate and extend our studies, we have

  18. Development of beam halo monitors for the European XFEL using radiation hard sensors and demonstration of the technology at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Ignatenko, Alexandr

    2015-05-15

    The European X-Ray Free-Electron Laser (E-XFEL), currently under construction in Hamburg, Germany, is intended to be an international linear accelerator (linac) based user facility. Its electron beam can carry maximal average power of 600 kW. A beam with such a high power needs to be carefully transmitted through the machine and safely dumped after utilization. This is supported by various diagnostics tools. A Beam Halo Monitor (BHM) based on synthetic diamond and sapphire sensors has been designed. Diamond sensors are developed by the company element6 for the detection of ionizing radiation and used previously elsewhere. Sapphire sensors are in this thesis applied for the first time. The BHM concept has been applied already at the Free-electron Laser in Hamburg (FLASH). A module with four diamond and four sapphire sensors was designed, installed inside the beam pipe, commissioned, calibrated and has been successfully operated for 4 years. The system contributed significantly to safe and efficient operation of FLASH. Both types of the sensors for the BHM were characterized. Measurements of radiation tolerance are done in a 10 MeV electron beam for polycrystalline CVD (pCVD) diamond sensors for the first time up to a dose of 10 MGy and for sapphire sensors up to 5 MGy. The charge collection efficiency (CCE) drops as a function of the absorbed dose, is however still sufficient for application as a BHM. To improve a main sensor characteristic, the charge collection efficiency, for sapphire sensors the impurity concentration was reduced and different growth techniques were compared. Finally, charge collection efficiency of about 5 % for a bias voltage of 500 V was reached. The BHM concept for the XFEL is designed and in the construction phase.

  19. Fast kilovoltage/megavoltage (kVMV) breathhold cone-beam CT for image-guided radiotherapy of lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wertz, Hansjoerg; Stsepankou, Dzmitry; Blessing, Manuel; Boda-Heggemann, Judit; Hesser, Juergen; Lohr, Frank; Wenz, Frederik [Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim (Germany); Rossi, Michael; Gros, Uwe [Elekta Ltd, Hamburg (Germany); Knox, Chris; Brown, Kevin [Elekta Ltd, Crawley (United Kingdom); Walter, Cornelia, E-mail: hansjoerg.wertz@umm.d [Department of Radiation Oncology, Marienhospital Stuttgart (Germany)

    2010-08-07

    Long image acquisition times of 60-120 s for cone-beam CT (CBCT) limit the number of patients with lung cancer who can undergo volume image guidance under breathhold. We developed a low-dose dual-energy kilovoltage-megavoltage-cone-beam CT (kVMV-CBCT) based on a clinical treatment unit reducing imaging time to {<=}15 s. Simultaneous kVMV-imaging was achieved by dedicated synchronization hardware controlling the output of the linear accelerator (linac) based on detector panel readout signals, preventing imaging artifacts from interference of the linac's MV-irradiation and panel readouts. Optimization was performed to minimize the imaging dose. Single MV-projections, reconstructed MV-CBCT images and images of simultaneous 90{sup 0} kV- and 90{sup 0} MV-CBCT (180{sup 0} kVMV-CBCT) were acquired with different parameters. Image quality and imaging dose were evaluated and compared to kV-imaging. Hardware-based kVMV synchronization resulted in artifact-free projections. A combined 180{sup 0} kVMV-CBCT scan with a total MV-dose of 5 monitor units was acquired in 15 s and with sufficient image quality. The resolution was 5-6 line pairs cm{sup -1} (Catphan phantom). The combined kVMV-scan dose was equivalent to a kV-radiation scan dose of {approx}33 mGy. kVMV-CBCT based on a standard linac is promising and can provide ultra-fast online volume image guidance with low imaging dose and sufficient image quality for fast and accurate patient positioning for patients with lung cancer under breathhold.

  20. Optimizations of transverse projected emittance at the photo-injector test facility at DESY, location Zeuthen

    Energy Technology Data Exchange (ETDEWEB)

    Rimjaem, S., E-mail: r.sakhorn@gmail.com [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Stephan, F.; Krasilnikov, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Ackermann, W. [Technische Universtaet Darmstadt, Schossgartenstrasse 8, 64289 Darmstadt (Germany); Asova, G.; Baehr, J. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Gjonaj, E. [Technische Universtaet Darmstadt, Schossgartenstrasse 8, 64289 Darmstadt (Germany); Grabosch, H.J.; Hakobyan, L.; Haenel, M.; Ivanisenko, Y.; Khojoyan, M.; Klemz, G. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Lederer, S. [Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22607 Hamburg (Germany); Mahgoub, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); Michelato, P.; Monaco, L. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano - LASA, Via F.lli Cervi 201, 20090 Segrate Milano (Italy); Nozdrin, M.; O' Shea, B.; Otevrel, M. [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, 15738 Zeuthen (Germany); and others

    2012-04-11

    High brightness electron sources for linac based short-wavelength free-electron lasers are developed and optimized for small transverse projected emittance at the photo-injector test facility at DESY, location Zeuthen (PITZ). A major part of the measurement program at PITZ is dedicated to transverse phase space optimization in order to fulfill the requirements of the European X-ray free-electron laser (European XFEL). A laser-driven RF-gun, treated with a dry-ice sublimation-impulse cleaning technique, a new photocathode laser system allowing short rise and fall times of the flat-top temporal distribution as well as several new diagnostic components have been installed at PITZ in 2008. The electrons generated via the photo-effect at a cesium telluride (Cs{sub 2}Te) cathode are accelerated by a 1.6 cell L-band RF-gun cavity with a maximum accelerating gradient at the cathode of about 60 MV/m. The transverse projected emittance is measured using a single slit scan technique. In the 2008-2009 run period, a detailed characterization of the projected transverse emittance was performed at different operating conditions. Optimizations and measurement results as well as simulation predictions of the transverse projected emittance for bunch charges of 1, 0.5, 0.25 and 0.1 nC are presented and discussed in this paper. The geometric mean of the normalized projected rms emittance in both transverse directions for an electron bunch charge of 1 nC was measured to be 0.89{+-}0.01 mm mrad for a 100% rms phase-space distribution.

  1. Fiber-optic triggered release of liposome in vivo: implication of personalized chemotherapy

    Directory of Open Access Journals (Sweden)

    Huang HL

    2015-08-01

    Full Text Available Huei-Ling Huang,1 Pei-Hsuan Lu,1 Hung-Chih Yang,1 Gi-Da Lee,1,2 Han-Ru Li,1 Kuo-Chih Liao1 1Graduate Institute of Biomedical Engineering, National Chung Hsing University, 2Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan Abstract: The aim of this research is to provide proof of principle by applying the fiber-optic triggered release of photo-thermally responsive liposomes embedded with gold nanoparticles (AuNPs using a 200 µm fiber with 65 mW and 532 nm excitation for topical release in vivo. The tunable delivery function can be paired with an apoptosis biosensor based on the same fiber-optic configuration for providing real-time evaluation of chemotherapy efficacy in vivo to perform as a personalized chemotherapy system. The pattern of topical release triggered by laser excitation conveyed through optical fibers was monitored by the increase in fluorescence resulting from the dilution of self-quenching (75 mM fluorescein encapsulated in liposomes. In in vitro studies (in 37°C phosphate buffer saline, the AuNP-embedded liposomes showed a more efficient triggered release (74.53%±1.63% in 40 minutes than traditional temperature-responsive liposomes without AuNPs (14.53%±3.17% or AuNP-liposomes without excitation (21.92%±2.08% by spectroscopic measurements. Using the mouse xenograft studies, we first demonstrated that the encapsulation of fluorescein in liposomes resulted in a more substantial content retention (81% in the tumor than for free fluorophores (14% at 120 minutes after administration from in vivo fluorescence imaging. Furthermore, the preliminary results also suggested the tunable release capability of the system by demonstrating consecutive triggered releases with fiber-optic guided laser excitation. Keywords: fiber-optic guided excitation, light excitation triggered release, photo-thermal responsive liposome, gold nanoparticles, tunable release in vivo

  2. SU-E-J-13: Six Degree of Freedom Image Fusion Accuracy for Cranial Target Localization On the Varian Edge Stereotactic Radiosurgery System: Comparison Between 2D/3D and KV CBCT Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H [Wayne State University, Detroit, MI (United States); Song, K; Chetty, I; Kim, J [Henry Ford Health System, Detroit, MI (United States); Wen, N [Henry Ford Health System, West Bloomfield, MI (United States)

    2015-06-15

    -based system provides accurate target positioning for frameless image-guided cranial stereotactic radiosurgery.

  3. A new strategy of CyberKnife treatment system based radiosurgery followed by early use of adjuvant bevacizumab treatment for brain metastasis with extensive cerebral edema.

    Science.gov (United States)

    Wang, Yang; Wang, Enmin; Pan, Li; Dai, Jiazhong; Zhang, Nan; Wang, Xin; Liu, Xiaoxia; Mei, Guanghai; Sheng, Xiaofang

    2014-09-01

    Bevacizumab blocks the effects of vascular endothelial growth factor in leakage-prone capillaries and has been suggested as a new treatment for cerebral radiation edema and necrosis. CyberKnife is a new, frameless stereotactic radiosurgery system. This work investigated the safety and efficacy of CyberKnife followed by early bevacizumab treatment for brain metastasis with extensive cerebral edema. The eligibility criteria of the patients selected for radiosurgery followed by early use of adjuvant bevacizumab treatment were: (1) brain tumors from metastasis with one solitary brain lesion and symptomatic extensive cerebral edema; (2) >18 years of age; (3) the patient refused surgery due to the physical conditions and the risk of surgery; (4) no contraindications for bevacizumab. (5) bevacizumab was applied for a minimum of 2 injections and a maximum of 6 injections with a 2-week interval between treatments, beginning within 2 weeks of the CyberKnife therapy; (6) Karnofsky performance status (KPS) ≥30. Tumor size and edema were monitored by magnetic resonance imaging (MRI). Dexamethasone dosage, KPS, adverse event occurrence and associated clinical outcomes were also recorded. Eight patients were accrued for this new treatment. Radiation dose ranged from 20 to 33 Gy in one to five sessions, prescribed to the 61-71 % isodose line. Bevacizumab therapy was administered 3-10 days after completion of CyberKnife treatment for a minimum of two cycles (5 mg/kg, at 2-week intervals). MRI revealed average reductions of 55.8 % (post-gadolinium) and 63.4 % (T2/FLAIR). Seven patients showed significant clinical neurological improvements. Dexamethasone was reduced in all patients, with five successfully discontinuing dexamethasone treatment 4 weeks after bevacizumab initiation. Hypertension, a bevacizumab-related adverse event, occurred in one patient. After 3-8 months, all patients studied were alive and primary brain metastases were under control, 2 developed new brain

  4. Intrauterine device quo vadis? Why intrauterine device use should be revisited particularly in nulliparous women?

    Directory of Open Access Journals (Sweden)

    Wildemeersch D

    2015-01-01

    uterus are viewed as second best. Conclusion: One of the reasons of the high unintended pregnancy rate in the USA may be the paucity of suitable IUDs. Also, the legal climate in the USA seems to be a problem for developers as many lawsuits have recently been reported. Clinical studies conducted in young nulliparous and adolescent women suggest that IUDs that fit well in the uterine cavity, like a shoe, result in better tolerance, less side effects, and last but not least, higher use continuation rates. Keywords: IUD screening, counseling, frameless IUD/IUS, adapted IUDs, efficacy, tolerance, continuation rate

  5. Neuronavigator-guided percutaneous radiofrequency thermocoagulation in the treatment of intractable trigeminal neuralgia

    Institute of Scientific and Technical Information of China (English)

    XU Shu-jun; ZHANG Wen-hua; CHEN Teng; WU Cheng-yuan; ZHOU Mao-de

    2006-01-01

    Background Percutaneous radiofrequency thermocoagulation of the trigeminal ganglion (PRTTG) is regarded as the first choice for most patients with trigeminal neuralgia (TN) because of its safety and feasibility. However,neuronavigator-guided PRTTG has been seldom reported. The purpose of this study was to assess the safety and efficacy of neuronavigator-guided PRTTG for the treatment of intractable TN.Methods Between January 2000 and December 2004, 54 patients with intractable TN were enrolled into this study and were randomly divided into two groups. The patients in navigation group (n=26) underwent PRTTG with frameless neuronavigation, and those in control group (n=28) received PRTTG without neuronavigation.Three months after the operation, the efficacy, side effects, and complications of the surgery were recorded. The patients in the control group were followed up for 10 to 54 months (mean, 34±5), and those in the navigation group were followed up for 13 to 58 months (mean, 36±7). Kaplan-Meier analyses of the pain-free survival curves were used for the censored survival data, and the log-rank test was used to compare survival curves of the two groups.Results The immediate complete pain-relief rate of the navigation group was 100%, whereas it was 95% in the control. The proportion of sustained pain-relief rates at 12, 24 and 36 months after the procedure were 85%, 77%,and 62% in the navigation group, and 54%, 40%, and 35% in the control. Recurrences in the control group were more common than that in the navigation group. Annual recurrence rate in the first and second years were 15% and 23% in the navigation group, and 46%, 60% in the control group. No side-effect and complication was noted in the navigation group except minimal facial hypesthesia.Conclusion Neuronavigator-guided PRTTG is a safe and promising method for treatment of intractable TN with better short- and long-term outcomes and lower complication rate than PRTTG without neuronavigation.

  6. Contraception - Update and Trends

    Directory of Open Access Journals (Sweden)

    Rabe T

    2010-01-01

    Full Text Available Fertility control in the future will focus on the improvement of existing methods (efficacy, side effects, easy use, duration of action, manufacturing process, costs, on new approaches (mode of action bringing additional health benefits, and on new targets for nonhormonal contraception. Counselling of women in view to contraceptive choices based on the individual risk (e. g. cardiovascular disease, thrombophilia, family risk of breast cancer, sexually transmitted diseases will gain more and more importance. Only a few companies can afford research in contraception such as Bayer-Schering-Pharma, and MSD. Female contraception: Ovulation inhibition: preselection of patients to minimize the individual risk. New oral contraceptive (OC regimen, OC with new progestins, OC with estradiol or estradiol esters, new ovulation inhibitors with new progestins and new regimen including long cycles and continuous delivery of steroidal contraceptives, new contraceptive patches, vaginal rings andsprayon contraceptives. Recently identified genes involved in the ovulation process as new targets for ovulation inhibitors. Fertilisation inhibition: new intrauterine systems have been developed: a smaller Mirena intrauterine system releasing levonorgestrel (LNG and a new frameless progestinreleasing intrauterine systems (IUS. Various new contraceptive barriers have been introduced. Research is ongoing on substances acting both as spermicide and as microbicides as a dualprotection method reducing both the risk of unwanted pregnancy and the risk of sexually transmitted diseases. New implantable systems and improved injectables (with improved pharmacokinetic profile, decreased side effects and a safer delivery system have been made available recently. Various new approaches in female sterilisation include non invasive method of tubal occlusion Immunocontraception for the female will not be available in the near future. Implantation inhibition: selective progesterone

  7. Adaptive fractionated stereotactic Gamma Knife radiotherapy of meningioma using integrated stereotactic cone-beam-CT and adaptive re-planning (a-gkFSRT).

    Science.gov (United States)

    Stieler, F; Wenz, F; Abo-Madyan, Y; Schweizer, B; Polednik, M; Herskind, C; Giordano, F A; Mai, S

    2016-11-01

    The Gamma Knife Icon (Elekta AB, Stockholm, Sweden) allows frameless stereotactic treatment using a combination of cone beam computer tomography (CBCT), a thermoplastic mask system, and an infrared-based high-definition motion management (HDMM) camera system for patient tracking during treatment. We report on the first patient with meningioma at the left petrous bone treated with adaptive fractionated stereotactic radiotherapy (a-gkFSRT). The first patient treated with Gamma Knife Icon at our institute received MR imaging for preplanning before treatment. For each treatment fraction, a daily CBCT was performed to verify the actual scull/tumor position. The system automatically adapted the planned shot positions to the daily position and recalculated the dose distribution (online adaptive planning). During treatment, the HDMM system recorded the intrafractional patient motion. Furthermore, the required times were recorded to define a clinical treatment slot. Total treatment time was around 20 min. Patient positioning needed 0.8 min, CBCT positioning plus acquisition 1.65 min, CT data processing and adaptive planning 2.66 min, and treatment 15.6 min. The differences for the five daily CBCTs compared to the reference are for rotation: -0.59 ± 0.49°/0.18 ± 0.20°/0.05 ± 0.36° and for translation: 0.94 ± 0.52 mm/-0.08 ± 0.08 mm/-1.13 ± 0.89 mm. Over all fractions, an intrafractional movement of 0.13 ± 0.04 mm was observed. The Gamma Knife Icon allows combining the accuracy of the stereotactic Gamma Knife system with the flexibility of fractionated treatment with the mask system and CBCT. Furthermore, the Icon system introduces a new online patient tracking system to the clinical routine. The interfractional accuracy of patient positioning was controlled with a thermoplastic mask and CBCT.

  8. Commissioning of the Leksell Gamma Knife(®) Icon™.

    Science.gov (United States)

    Zeverino, Michele; Jaccard, Maud; Patin, David; Ryckx, Nick; Marguet, Maud; Tuleasca, Constantin; Schiappacasse, Luis; Bourhis, Jean; Levivier, Marc; Bochud, Francois O; Moeckli, Raphaël

    2017-02-01

    The Leksell Gamma Knife (LGK) Icon has been recently introduced to provide Gamma Knife technology with frameless stereotactic treatments which use an additional cone-beam CT (CBCT) imaging system and a motion tracking system (IFMM, Intra-Fraction Motion Management). The system was commissioned for the treatment unit itself as well as the imaging system. The LGK Icon was calibrated using an A1SL ionization chamber. EBT3 radiochromic films were employed to independently check the machine calibration, to measure the relative output factors (ROFs) and to collect dose distributions. Coincidence between CBCT isocenter and radiological focus was evaluated by means of EBT3 films. CBCT image quality was investigated in terms of spatial resolution, contrast-to-noise ratio (CNR), and uniformity for the two presets available (low dose and high dose). Computed Tomography Dose Index (CTDI) was also measured for both presets. The absolute dose rate of the LGK Icon was 3.86 ± 0.09 Gy/min. This result was confirmed by EBT3 readings. ROF were found to be 0.887 ± 0.035 and 0.797 ± 0.032 for the 8 mm and 4 mm collimators, respectively, which are within 2% of the Monte Carlo-derived ROF values. Excellent agreement was found between calculated and measured dose distribution with the gamma pass rate >95% of points for the nine dose distributions analyzed with 3%/1 mm criteria. CBCT isocenter was found to be within 0.2 mm with respect to radiological focus. Image quality parameters were found to be well within the manufacturer's specifications with the high-dose preset being superior in terms of CNR and uniformity. CTDI values were 2.41 mGy and 6.32 mGy, i.e. -3.6% and 0.3% different from the nominal values for the low-dose and high-dose presets, respectively. The LGK Icon was successfully commissioned for clinical use. The use of the EBT3 to characterize the treatment unit was demonstrated to be feasible. The CBCT imaging system operates well within the manufacturer's specifications

  9. Stereotactic probability and variability of speech arrest and anomia sites during stimulation mapping of the language dominant hemisphere.

    Science.gov (United States)

    Chang, Edward F; Breshears, Jonathan D; Raygor, Kunal P; Lau, Darryl; Molinaro, Annette M; Berger, Mitchel S

    2017-01-01

    OBJECTIVE Functional mapping using direct cortical stimulation is the gold standard for the prevention of postoperative morbidity during resective surgery in dominant-hemisphere perisylvian regions. Its role is necessitated by the significant interindividual variability that has been observed for essential language sites. The aim in this study was to determine the statistical probability distribution of eliciting aphasic errors for any given stereotactically based cortical position in a patient cohort and to quantify the variability at each cortical site. METHODS Patients undergoing awake craniotomy for dominant-hemisphere primary brain tumor resection between 1999 and 2014 at the authors' institution were included in this study, which included counting and picture-naming tasks during dense speech mapping via cortical stimulation. Positive and negative stimulation sites were collected using an intraoperative frameless stereotactic neuronavigation system and were converted to Montreal Neurological Institute coordinates. Data were iteratively resampled to create mean and standard deviation probability maps for speech arrest and anomia. Patients were divided into groups with a "classic" or an "atypical" location of speech function, based on the resultant probability maps. Patient and clinical factors were then assessed for their association with an atypical location of speech sites by univariate and multivariate analysis. RESULTS Across 102 patients undergoing speech mapping, the overall probabilities of speech arrest and anomia were 0.51 and 0.33, respectively. Speech arrest was most likely to occur with stimulation of the posterior inferior frontal gyrus (maximum probability from individual bin = 0.025), and variance was highest in the dorsal premotor cortex and the posterior superior temporal gyrus. In contrast, stimulation within the posterior perisylvian cortex resulted in the maximum mean probability of anomia (maximum probability = 0.012), with large variance

  10. Intraoperative computed tomography with integrated navigation system in spinal stabilizations.

    Science.gov (United States)

    Zausinger, Stefan; Scheder, Ben; Uhl, Eberhard; Heigl, Thomas; Morhard, Dominik; Tonn, Joerg-Christian

    2009-12-15

    STUDY DESIGN.: A prospective interventional case-series study plus a retrospective analysis of historical patients for comparison of data. OBJECTIVE.: To evaluate workflow, feasibility, and clinical outcome of navigated stabilization procedures with data acquisition by intraoperative computed tomography. SUMMARY OF BACKGROUND DATA.: Routine fluoroscopy to assess pedicle screw placement is not consistently reliable. Our hypothesis was that image-guided spinal navigation using an intraoperative CT-scanner can improve the safety and precision of spinal stabilization surgery. METHODS.: CT data of 94 patients (thoracolumbar [n = 66], C1/2 [n = 12], cervicothoracic instability [n = 16]) were acquired after positioning the patient in the final surgical position. A sliding gantry 40-slice CT was used for image acquisition. Data were imported to a frameless infrared-based neuronavigation workstation. Intraoperative CT was obtained to assess the accuracy of instrumentation and, if necessary, the extent of decompression. All patients were clinically evaluated by Odom-criteria after surgery and after 3 months. RESULTS.: Computed accuracy of the navigation system reached /=2 mm without persistent neurologic or vascular damage in 20/414 screws (4.8%) leading to immediate correction of 10 screws (2.4%). Control-iCT changed the course of surgery in 8 cases (8.5% of all patients). The overall revision rate was 8.5% (4 wound revisions, 2 CSF fistulas, and 2 epidural hematomas). There was no reoperation due to implant malposition. According to Odom-criteria all patients experienced a clinical improvement. A retrospective analysis of 182 patients with navigated thoracolumbar transpedicular stabilizations in the preiCT era revealed an overall revision rate of 10.4% with 4.4% of patients requiring screw revision. CONCLUSION.: Intraoperative CT in combination with neuronavigation provides high accuracy of screw placement and thus safety for patients undergoing spinal stabilization

  11. 26+ Year Old Photovoltaic Power Plant: Degradation and Reliability Evaluation of Crystalline Silicon Modules -- South Array

    Science.gov (United States)

    Olakonu, Kolapo

    As the use of photovoltaic (PV) modules in large power plants continues to increase globally, more studies on degradation, reliability, failure modes, and mechanisms of field aged modules are needed to predict module life expectancy based on accelerated lifetime testing of PV modules. In this work, a 26+ year old PV power plant in Phoenix, Arizona has been evaluated for performance, reliability, and durability. The PV power plant, called Solar One, is owned and operated by John F. Long's homeowners association. It is a 200 kW dc, standard test conditions (STC) rated power plant comprised of 4000 PV modules or frameless laminates, in 100 panel groups (rated at 175 kW ac). The power plant is made of two center-tapped bipolar arrays, the north array and the south array. Due to a limited time frame to execute this large project, this work was performed by two masters students (Jonathan Belmont and Kolapo Olakonu) and the test results are presented in two masters theses. This thesis presents the results obtained on the south array and the other thesis presents the results obtained on the north array. Each of these two arrays is made of four sub arrays, the east sub arrays (positive and negative polarities) and the west sub arrays (positive and negative polarities), making up eight sub arrays. The evaluation and analyses of the power plant included in this thesis consists of: visual inspection, electrical performance measurements, and infrared thermography. A possible presence of potential induced degradation (PID) due to potential difference between ground and strings was also investigated. Some installation practices were also studied and found to contribute to the power loss observed in this investigation. The power output measured in 2011 for all eight sub arrays at STC is approximately 76 kWdc and represents a power loss of 62% (from 200 kW to 76 kW) over 26+ years. The 2011 measured power output for the four south sub arrays at STC is 39 kWdc and represents a power

  12. Universal structure motifs in biominerals: a lesson from nature for the efficient design of bioinspired functional materials.

    Science.gov (United States)

    Harris, Joe; Böhm, Corinna F; Wolf, Stephan E

    2017-08-06

    Biominerals are typically indispensable structures for their host organism in which they serve varying functions, such as mechanical support and protection, mineral storage, detoxification site, or as a sensor or optical guide. In this perspective article, we highlight the occurrence of both structural diversity and uniformity within these biogenic ceramics. For the first time, we demonstrate that the universality-diversity paradigm, which was initially introduced for proteins by Buehler et al. (Cranford & Buehler 2012 Biomateriomics; Cranford et al. 2013 Adv. Mater.25, 802-824 (doi:10.1002/adma.201202553); Ackbarow & Buehler 2008 J. Comput. Theor. Nanosci.5, 1193-1204 (doi:10.1166/jctn.2008.001); Buehler & Yung 2009 Nat. Mater.8, 175-188 (doi:10.1038/nmat2387)), is also valid in the realm of biomineralization. A nanogranular composite structure is shared by most biominerals which rests on a common, non-classical crystal growth mechanism. The nanogranular composite structure affects various properties of the macroscale biogenic ceramic, a phenomenon we attribute to emergence. Emergence, in turn, is typical for hierarchically organized materials. This is a clear call to renew comparative studies of even distantly related biomineralizing organisms to identify further universal design motifs and their associated emergent properties. Such universal motifs with emergent macro-scale properties may represent an unparalleled toolbox for the efficient design of bioinspired functional materials.

  13. Development of a resin curing model for UV nanoimprint.

    Science.gov (United States)

    Lee, Jin Woo; Cho, Dong-Woo

    2005-10-01

    UV nanoimprint lithography uses UV light as an energy source. It is performed at room temperature and low pressure, and has its own merits as compared to thermal nanoimprint. In this paper, a measurement system was developed to measure the degree of resin curing in UV nanoimprint to improve our understanding of the resin solidification phenomenon. A curing model was then established based on the measurement results. The measurement system measured the degree of cure in real time and was composed of a Fourier transform infrared spectroscopy system, a UV light source, and an optical guide. Also, new UV-curable resins that had low viscosity values were developed for the UV nanoimprint process, and imprint tests using these resins were performed successfully. The curing model considered the UV irradiation time, power, and curing temperature, which are important parameters in the UV nanoimprint process. The degree of cure had an exponential relation to UV irradiation time, power, and temperature; thus, the curing model was expressed as an exponential function of the UV irradiation time, power, and temperature. The developed model was verified for various UV-curable resins.

  14. Design of a Novel Photobioreactor for Culture of Microalgae

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents the design of a novel photobioreactor for cultivation of microalgae. The body of the reactor with volume of about 40 L is parallelipipedic and divided in five compartments that can be put in series. The optical guides, plunged perpendicularly into the compartments, are upright Plexiglas plates on which side faces there are defined grooves that are able to diffuse light laterally and ensure an even distribution of light in the medium. External airlifts through the side columns are used for mixing of culture medium. The external light source is a SON-T lamp mounted inside a projector that provides a conical light dispersion, it is interchangeable and may take different positions. The design offers the photobioreactor characteristics including mainly interchangeable light source, homogenous distribution of light, perfect mixing of suspension of algae, high ratio of illuminating surface to volume of reactor, compactness and absence of contamination. Schemes, view of the photobioractor and data of continuous culture for Spirulina maxima are presented.

  15. The New Mexico Tech Extrasolar Spectroscopic Survey Instrument (NESSI)

    Science.gov (United States)

    Creech-Eakman, Michelle J.; Jurgenson, C.; Vasisht, G.; Swain, M.; Boston, P.; Santoro, F.

    2010-01-01

    We present the design and scientific objectives behind NESSI, a near-infrared spectroscopic purpose-built for studying exoplanet atmospheres. This instrument is being designed and assembled by a team of scientists and engineers at New Mexico Tech (NMT), the Magdalena Ridge Observatory (MRO) and NASA's Jet Propulsion Lab (JPL), and is scheduled for deployment in late 2010 at the MRO 2.4m telescope. NESSI's unique design is driven by recent space and ground-based NIR spectroscopy of exoplanet atmospheres by members of our team. Optimization of the instrument to achieve 0.01% relative accuracies in spectra of exoplanetary molecular constituents requires careful attention to certain design features and a new technical approach. We present an overview of NESSI's design, including the four major subassemblies: 1) a field derotator, 2) a reimaging module, 3) an optical guiding module, and 4) a multi-object spectrograph subassembly. We also present an overview of our science program specifically designed to build the community of exoplanet researchers and students in NM. The financial support of our team and NESSI itself have been made possible by a NM NASA EPSCoR grant, matching funds from the NMT administration, and internal support for the NESSI hardware from Dr. Van Romero, NMT's Research Vice-President.

  16. 基于空域的光学动像传递函数数学模型建立方法研究%Study on construction method of mathematical models for optical transfer function of motive image based on airspace

    Institute of Scientific and Technical Information of China (English)

    潘鸿飞

    2012-01-01

    从调制传递函数的研究出发,分析了动像传递函数模型建立对应的运动状态,提出了基于基于空域的动像传递函数数学模型建立方法,建立了动像传递函数的曲线,并对动像传递函数曲线的物理意义进行了详细分析,该研究可以应用于光学制导武器动态等效测试等方面.%Transfer function models of motive image is analysed and the corresponding movement states are established, according to the research of the transfer function modulation firstly. Then .the construction of the mathematical models for transfer function of the motive image in space field is proposed. Moreover,the transfer function curve of motive image is built and its physical significance is analyzed in detail. The research in this paper can be applied in the dynamic equivalent test of the optical guide weapons.

  17. New magnet transport system for the LHC beam transfer lines

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system (pictured here in one of the tunnels) is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. The lead vehicle is powered by an electric rail set into the roof of the tunnel. The system is backed up by electrical batteries that enable it to operate in the absence of an outside power source or in the event of power failure. Last but not least, for the long-distance transport of magnets, it can be optically guided by a line traced on the tunnel floor. The convoy moves through the particularly narr...

  18. Optogenetic toolkit reveals the role of Ca2+ sparklets in coordinated cell migration.

    Science.gov (United States)

    Kim, Jin Man; Lee, Minji; Kim, Nury; Heo, Won Do

    2016-05-24

    Cell migration is controlled by various Ca(2+) signals. Local Ca(2+) signals, in particular, have been identified as versatile modulators of cell migration because of their spatiotemporal diversity. However, little is known about how local Ca(2+) signals coordinate between the front and rear regions in directionally migrating cells. Here, we elucidate the spatial role of local Ca(2+) signals in directed cell migration through combinatorial application of an optogenetic toolkit. An optically guided cell migration approach revealed the existence of Ca(2+) sparklets mediated by L-type voltage-dependent Ca(2+) channels in the rear part of migrating cells. Notably, we found that this locally concentrated Ca(2+) influx acts as an essential transducer in establishing a global front-to-rear increasing Ca(2+) gradient. This asymmetrical Ca(2+) gradient is crucial for maintaining front-rear morphological polarity by restricting spontaneous lamellipodia formation in the rear part of migrating cells. Collectively, our findings demonstrate a clear link between local Ca(2+) sparklets and front-rear coordination during directed cell migration.

  19. Thin-film perovskites-ferroelectric materials for integrated optics

    Energy Technology Data Exchange (ETDEWEB)

    Walker, F.J. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States); McKee, R.A. [Oak Ridge National Lab., TN (United States)

    1995-12-31

    Optical guided wave (OGW) devices, based on LiNbO{sub 3} or GaAs. are commercially available products with established markets and applications. While LiNbO{sub 3} presently dominates the commercial applications, there are several drivers for the development of improved electro-optic (EO) materials. If the appropriate crystal quality could be obtained for thin-film BaTiO{sub 3} supported on MgO for example, or for an integrated BaTiO{sub 3}/Mg0 structure on silicon or GaAs, then the optimum OGW device structure might be realized. We report on our results for the growth of optical quality, epitaxial BaTiO{sub 3} and SrTiO{sub 3} on single-crystal MgO substrates using source shuttering molecular beam epitaxy (MBE) techniques. We also discuss how these materials can be integrated onto silicon. Our MBE studies show that, for this important class of perovskite oxides, heteroepitaxy between the perovskites and alkaline earth oxides is dominated by interfacial electrostatics at the first atomic layers. We have been able to demonstrate that a layer-by-layer energy minimization associated with interfacial electrostatics leads to the growth of high quality thin films of these materials. We have fabricated waveguides from these materials, and the optical clarity and loss coefficients have been characterized and found to be comparable to in-diffused waveguide structures typically represented by Ti drifted LiNbO{sub 3}.

  20. Surface-etched distributed Bragg reflector lasers in photonic integrated circuits

    Science.gov (United States)

    Price, Raymond Kirk

    Semiconductor lasers have been used as a highly efficient, coherent source of light for commercial, industrial, and medical applications. Recently, much work has been done to engineer optical devices with a high degree of functionality. Photonic integrated circuits (PICs) achieve technology's twin goals of miniaturization and integration by implementing multiple optical functions on a single chip. This dissertation shows that asymmetric cladding surface-etched distributed Bragg reflector (ACSE-DBR) lasers are ideal candidates for monolithic photonic integration for the purpose of optical heterodyning. The active laser devices in these ACSE-DBR lasers exhibit high quantum efficiencies, tunable performance, and narrow spectral linewidths. The asymmetric cladding ridge waveguides are shown to provide low-loss routing structures, enabling monolithic integration of active and passive devices with a small layout footprint. This technology is applied to two specific purposes: a dual wavelength source for generating terahertz radiation via optical heterodyning, and high-power DBR laser arrays for spectral beam combining. A dual-wavelength PIC at 850 nm for the purpose of optical heterodyning is presented in this work. The engineering of the active and passive structures is extensively analyzed. These structures are shown to be ideally suited for high pulsed-power optical heterodyning applications. A high-power DBR laser array is also presented for use in spectral beam combining systems. The laser structure for this application is engineered for high-power applications. The engineering of the lateral optical guiding structure as well as the surface-etched grating is discussed.

  1. Diagnostic and therapeutic peroral cholangioscopy

    Directory of Open Access Journals (Sweden)

    Jong Ho Moon

    2012-01-01

    Full Text Available Peroral cholangioscopy (POC provides direct visualization of the bile duct and facilitates diagnostic or therapeutic intervention. The currently available single-operator POC systems are "Mother-baby" scope system, SpyGlass direct visualization system, and direct POC using a regular ultra-slim upper endoscope. Direct POC using an ultra-slim upper endoscope having a larger 2-mm working channel can provide a valuable and economic solution for evaluating bile-duct lesions. Main diagnostic procedures under direct POC are visual characterization and optically guided target biopsy for the indeterminate bile duct lesion. Image-enhanced endoscopy such as narrow-band imaging has shown promise for more detailed evaluation of mucosal abnormality and can be performed under direct POC. Intracorporeal lithotripsy such as electrohydraulic lithotripsy or laser lithotripsy is a main therapeutic intervention of direct POC for patients with bile duct stones that are resistant to conventional endoscopic stone-removal procedures. Besides, tumor ablation therapy, such as photodynamic therapy and argon plasma coagulation may be also performed using direct POC. Further developments of the endoscope and specialized accessories or devices are expected to facilitate diagnostic and therapeutic role of this cholangioscopic procedure.

  2. Dispersion properties and low infrared optical losses in epitaxial AlN on sapphire substrate in the visible and infrared range

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, A., E-mail: ali.soltani@iemn.univ-lille1.fr; Stolz, A.; Gerbedoen, J.-C.; Rousseau, M.; Bourzgui, N.; De Jaeger, J.-C. [Institut d' Électronique, Microélectronique et Nanotechnologie, UMR-CNRS 8520, PRES Université Lille Nord de France, Cité Scientifique, Avenue Poincaré, CS 60069, 59652 Villeneuve d' Ascq Cedex (France); Charrier, J. [Fonctions Optiques pour les Technologies de l' informatiON, UMR-CNRS 6082, ENSSAT 6, rue de Kerampont, CS 80518, 22305 Lannion Cedex (France); Mattalah, M. [Laboratoire de Microélectronique, Université Djilali Liabes, 22000 Sidi Bel Abbes (Algeria); Barkad, H. A. [Institut Universitaire Technologique Industriel, Université de Djibouti, Avenue Georges Clémenceau, BP 1904 Djibouti (Djibouti); Mortet, V. [Institute of Physics of Academy of Sciences of Czech Republic, Fyzikální ústav AV CR, v.v.i., Na Slovance 1999/2 (Czech Republic); BenMoussa, A. [Solar Terrestrial Center of Excellence, Royal Observatory of Belgium, Circular 3, B-1180 Brussels (Belgium)

    2014-04-28

    Optical waveguiding properties of a thick wurtzite aluminum nitride highly [002]-textured hetero-epitaxial film on (001) basal plane of sapphire substrate are studied. The physical properties of the film are determined by X-ray diffraction, atomic force microscopy, microRaman, and photocurrent spectroscopy. The refractive index and the thermo-optic coefficients are determined by m-lines spectroscopy using the classical prism coupling technique. The optical losses of this planar waveguide are also measured in the spectral range of 450–1553 nm. The lower value of optical losses is equal to 0.7 dB/cm at 1553 nm. The optical losses due to the surface scattering are simulated showing that the contribution is the most significant at near infrared wavelength range, whereas the optical losses are due to volume scattering and material absorption in the visible range. The good physical properties and the low optical losses obtained from this planar waveguide are encouraging to achieve a wide bandgap optical guiding platform from these aluminum nitride thin films.

  3. A Novel Label-Free Optical Biosensor Using Synthetic Oligonucleotides from E. coli O157:H7: Elementary Sensitivity Tests

    Directory of Open Access Journals (Sweden)

    Ahmet Yavuz Oral

    2009-06-01

    Full Text Available SiO2-TiO2 thin films for use as fiber optic guiding layers of optical DNA biosensors were fabricated by the sol-gel dip coating technique. The chemical structure and the surface morphology of the films were characterized before immobilization. Single probe DNA strands were immobilized on the surface and the porosity of the films before the hybridization process was measured. Refractive index values of the films were measured using a Metricon 2010 prism coupler. On the surface of each film, 12 different spots were taken for measurement and calculation of the mean refractive index values with their standard deviations. The increased refractive index values after the immobilization of single DNA strands indicated that immobilization was successfully achieved. A further refractive index increase after the hybridization with target single DNA strands showed the possibility of detection of the E. coli O157:H7 EDL933 species using strands of 20-mers (5’-TAATATCGGTTGCGGAGGTG -3’ sequence.

  4. AlGaN/AlN integrated photonics platform for the ultraviolet and visible spectral range.

    Science.gov (United States)

    Soltani, Mohammad; Soref, Richard; Palacios, Tomas; Englund, Dirk

    2016-10-31

    We analyze a photonic integrated circuit (PIC) platform comprised of a crystalline AlxGa1-xN optical guiding layer on an AlN substrate for the ultraviolet to visible (UV-vis) wavelength range. An Al composition of x~0.65 provides a refractive index difference of ~0.1 between AlxGa1-xN and AlN, and a small lattice mismatch (xGa1-xN/AlN interface. This small refractive index difference is beneficial at shorter wavelengths to avoid extra-small waveguide dimensions. The platform enables compact waveguides and bends with high field confinement in the wavelength range from 700 nm down to 300 nm (and potentially lower) with waveguide cross-section dimensions comparable to those used for telecom PICs such as silicon and silicon nitride waveguides, allowing for well-established optical lithography. This platform can potentially enable cost-effective, manufacturable, monolithic UV-vis photonic integrated circuits.

  5. Toward TW-Level, Hard X-Ray Pulses at LCLS

    Energy Technology Data Exchange (ETDEWEB)

    Fawley, W.M.; Frisch, J.; Huang, Z.; Jiao, Y.; Nuhn, H.-D.; /SLAC; Pellegrini, C.; /SLAC /UCLA; Reiche, S.; /PSI, Villigen; Wu, J,; /SLAC

    2011-12-13

    Coherent diffraction imaging of complex molecules such as proteins requires a large number (e.g., {approx} 10{sup 13}/pulse) of hard X-ray photons within a time scale of {approx} 10 fs or less. This corresponds to a peak power of {approx} 1 TW, much larger than that currently generated by LCLS or other proposed X-ray free electron lasers (FELs). We study the feasibility of producing such pulses using a LCLS-like, low charge electron beam, as will be possible in the LCLS-II upgrade project, employing a configuration beginning with a SASE amplifier, followed by a 'self-seeding' crystal monochromator, and finishing with a long tapered undulator. Our results suggest that TW-level output power at 8.3 keV is possible from a total undulator system length around 200 m. In addition power levels larger than 100 GW are generated at the third harmonic. We present a tapering strategy that extends the original 'resonant particle' formalism by optimizing the transport lattice to maximize optical guiding and enhance net energy extraction. We discuss the transverse and longitudinal coherence properties of the output radiation pulse and the expected output pulse energy sensitivity, both to taper errors and to power fluctuations on the monochromatized SASE seed.

  6. Terawatt x-ray free-electron-laser optimization by transverse electron distribution shaping

    Directory of Open Access Journals (Sweden)

    C. Emma

    2014-11-01

    Full Text Available We study the dependence of the peak power of a 1.5 Å Terawatt (TW, tapered x-ray free-electron laser (FEL on the transverse electron density distribution. Multidimensional optimization schemes for TW hard x-ray free-electron lasers are applied to the cases of transversely uniform and parabolic electron beam distributions and compared to a Gaussian distribution. The optimizations are performed for a 200 m undulator and a resonant wavelength of λ_{r}=1.5  Å using the fully three-dimensional FEL particle code genesis. The study shows that the flatter transverse electron distributions enhance optical guiding in the tapered section of the undulator and increase the maximum radiation power from a maximum of 1.56 TW for a transversely Gaussian beam to 2.26 TW for the parabolic case and 2.63 TW for the uniform case. Spectral data also shows a 30%–70% reduction in energy deposited in the sidebands for the uniform and parabolic beams compared with a Gaussian. An analysis of the transverse coherence of the radiation shows the coherence area to be much larger than the beam spotsize for all three distributions, making coherent diffraction imaging experiments possible.

  7. Photonic spatial reformatting of stellar light for diffraction-limited spectroscopy

    CERN Document Server

    Harris, Robert J; Choudhury, Debaditya; Morris, Tim J; Gendron, Eric; Basden, Alastair G; Brown, Graeme; Allington-Smith, Jeremy R; Thomson, Robert R

    2014-01-01

    The spectral resolution of a dispersive spectrograph is limited by the width of the entrance slit. This inherently means that astronomical spectrographs trade-off throughput with spectral resolving power. Recently, optical guided-wave transitions known as 'photonic-lanterns' have been proposed to circumvent this trade-off, by enabling the efficient reformatting of multimode light into a pseudo-slit which is highly multimode in one axis, but diffraction-limited in the other. Here, we demonstrate the successful reformatting of a telescope point-spread-function into such a slit using a three-dimensional integrated optical waveguide device, which we name the 'photonic-dicer'. Using the CANARY Adaptive-Optics system on the William Herschel Telescope, and broadband celestial light between 1350 nm and 1550 nm, the device exhibits throughputs of 19.5%, 10.5% and 9.0%, under closed-loop, open-loop and tip-tilt modes of operation respectively. This work clearly demonstrates that integrated photonic technologies can fac...

  8. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults.

    Science.gov (United States)

    Frerk, C; Mitchell, V S; McNarry, A F; Mendonca, C; Bhagrath, R; Patel, A; O'Sullivan, E P; Woodall, N M; Ahmad, I

    2015-12-01

    These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

  9. Modeling and multidimensional optimization of a tapered free electron laser

    Directory of Open Access Journals (Sweden)

    Y. Jiao

    2012-05-01

    Full Text Available Energy extraction efficiency of a free electron laser (FEL can be greatly increased using a tapered undulator and self-seeding. However, the extraction rate is limited by various effects that eventually lead to saturation of the peak intensity and power. To better understand these effects, we develop a model extending the Kroll-Morton-Rosenbluth, one-dimensional theory to include the physics of diffraction, optical guiding, and radially resolved particle trapping. The predictions of the model agree well with that of the GENESIS single-frequency numerical simulations. In particular, we discuss the evolution of the electron-radiation interaction along the tapered undulator and show that the decreasing of refractive guiding is the major cause of the efficiency reduction, particle detrapping, and then saturation of the radiation power. With this understanding, we develop a multidimensional optimization scheme based on GENESIS simulations to increase the energy extraction efficiency via an improved taper profile and variation in electron beam radius. We present optimization results for hard x-ray tapered FELs, and the dependence of the maximum extractable radiation power on various parameters of the initial electron beam, radiation field, and the undulator system. We also study the effect of the sideband growth in a tapered FEL. Such growth induces increased particle detrapping and thus decreased refractive guiding that together strongly limit the overall energy extraction efficiency.

  10. Image-guided endoscopic transnasal removal of recurrent pituitary adenomas.

    Science.gov (United States)

    Lasio, Giovanni; Ferroli, Paolo; Felisati, Giovanni; Broggi, Giovanni

    2002-07-01

    To assess the role that neuronavigation plays in assisting endoscopic transsphenoidal reoperations for recurrent pituitary adenomas. During a 45-month period, 19 endoscopic endonasal transsphenoidal reoperations were performed for recurrent pituitary adenomas. In 11 of 19 patients, the procedure was performed with the aid of an optically guided system. Clinical records were reviewed retrospectively, with attention to the following: comparison of baseline clinical data, the duration of surgery, and the postoperative course and complications of both image-guided and non-image-guided endoscopic reoperations. In addition, to test the reliability of the neuronavigation system, we made measurements of intraoperative accuracy in five additional transnasal endoscopic procedures in "virgin" noses and sphenoidal sinuses. In both groups studied, we found no difference with regard to either morbidity or mortality, which were null. The mean setup time was 13 minutes shorter in non-image-guided procedures (P = 0.021), and the operative time was 36 minutes shorter in image-guided procedures (P = 0.038). No other statistically significant differences were found between the two groups. In all cases, we found that the system performed without malfunction. Continuous information regarding instrument location and trajectory was provided to the surgeon. Measurements of the intraoperative accuracy in the axial, coronal, and sagittal planes indicated a mean intraoperatively verified system error of 1.6 +/- 0.6 mm. Neuronavigation can be applied during endonasal transsphenoidal endoscopic surgery and requires a minimal amount of time. It makes reoperation easier, faster, and probably safer.

  11. Wave-Based Subsurface Guide Star

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K

    2011-07-26

    Astronomical or optical guide stars are either natural or artificial point sources located above the Earth's atmosphere. When imaged from ground-based telescopes, they are distorted by atmospheric effects. Knowing the guide star is a point source, the atmospheric distortions may be estimated and, deconvolved or mitigated in subsequent imagery. Extending the guide star concept to wave-based measurement systems to include acoustic, seismo-acoustic, ultrasonic, and radar, a strong artificial scatterer (either acoustic or electromagnetic) may be buried or inserted, or a pre-existing or natural sub-surface point scatterer may be identified, imaged, and used as a guide star to determine properties of the sub-surface volume. That is, a data collection is performed on the guide star and the sub-surface environment reconstructed or imaged using an optimizer assuming the guide star is a point scatterer. The optimization parameters are the transceiver height and bulk sub-surface background refractive index. Once identified, the refractive index may be used in subsequent reconstructions of sub-surface measurements. The wave-base guide star description presented in this document is for a multimonostatic ground penetrating radar (GPR) but is applicable to acoustic, seismo-acoustic, and ultrasonic measurement systems operating in multimonostatic, multistatic, multibistatic, etc., modes.

  12. Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2017-05-21

    challenging issues for such high-brightness or high-intensity beam transport, as it would degrade lasing performance in the fourth-generation light sources, reduce cooling efficiency in electron cooling facilities, and compromise the luminosity of colliding beams in lepton or lepton-hadron colliders. The dissertation work will focus on the MBI in modern recirculating electron accelerators. It has been known that the collective interactions, the coherent synchrotron radiation (CSR) and the longitudinal space charge (LSC) forces, can drive MBI. The CSR effect is a collective phenomenon in which the electrons in a curved motion, e.g. a bending dipole, emit radiation at a scale comparable to the micro-bunched structure of the bunch distribution. The LSC effect stems from non-uniformity of the charge distribution, acts as plasma oscillation, and can eventually accumulate an amount of energy modulation when the beam traverses a long section of a beamline. MBI can be seeded by non-uniformity or shot noise of the beam, which originates from granularity of the elementary charge. Through the aforementioned collective effects, the modulation of the bunch sub-structure can be amplified and, once the beam-wave interaction formed a positive feedback, can result in MBI. The problem of MBI has been intensively studied for linac-based facilities and for storage-ring accelerators. However, systematic studies for recirculation machines are still very limited and form a knowledge gap. Because of the much more complicated machine configuration of the recirculating accelerators than that of linacs, the existing MBI analysis needs to be extended to accommodate the high-brightness particle beam transport in modern recirculating accelerators. This dissertation is focused on theoretical investigation of MBI in such machine configuration in the following seven themes: (1) Development and generalization of MBI theory The theoretical formulation has been extended so as to be applicable to a general

  13. SU-E-T-198: Hippocampal-Sparing Radiotherapy (HSRT) for Patients with Head and Neck Cancer (HNC) Using Intensity-Modulated Radiation Therapy (IMRT)

    Energy Technology Data Exchange (ETDEWEB)

    Dunlop, A; Welsh, L; Nutting, C; Harrington, K; Bhide, S; Newbold, K

    2014-06-01

    Purpose: There is increasing evidence that decline in cognitive function following brain radiotherapy (RT) is related to the radiation dose delivered to the hippocampi. In this work we evaluate the feasibility of using IMRT to generate HSRT plans in HNC. Methods: A planning study was undertaken for ten representative patients with HNC previously treated with radical (chemo)-RT using standard IMRT techniques. The hippocampi were delineated according to the RTOG hippocampal contouring atlas, on a T1w- MRI scan that was registered with the RT planning CT. LINAC-based, clinically acceptable, HSRT plans were generated and assessed using the Pinnacle3 treatment planning system. Results: Using a VMAT technique, a reduction in hippocampal dose was achievable in six cases. For these cases, the EQD2-D40% of the bilateral hippocampi was significantly reduced by HSRT (p = 0.006) from a median of 18.8Gy (range 14.4–34.6) to 6.5 Gy (4.2–9.5) for the delivered and HSRT plans respectively. Plans were also generated using a fixed-field IMRT technique with non-coplanar beams that were designed to avoid the bilateral hippocampi, resulting in a median EQD2-D40% of 11.2Gy (8.0–14.5). Both HSRT techniques also resulted in lower doses to the whole brain, brain stem, and cerebellum. The HSRT plans resulted in higher doses to some regions of non-contoured normaltissue, but the magnitude of these dose differences is unlikely to be of clinical significance in terms of acute and late toxicity. Conclusion: This study has demonstrated that it is possible, in many cases, to adapt treatment plans for HNC to significantly reduce dose to the hippocampi. This reduction in dose would be predicted to Resultin a significant reduction in the probability of subsequent decline in cognitive function following RT. Our results point towards the need for the collection of prospective data on cognitive outcomes for the HNC patient population treated with radical (chemo)-RT.

  14. SU-E-J-225: Quantitative Evaluation of Rigid and Non-Rigid Motion of Liver Tumors Using Stereo Imaging During SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q; Hanna, G; Kubicek, G; Asbell, S; Chen, Y; LaCouture, T [MD Anderson Cancer Center at Cooper, Mt Laurel, NJ (United States); Grimm, J [Holy Redeemer, Meadowbrook, PA (United States); Pahlajani, N [First Radiation and Oncology Group, Jacksonville, FL (United States); Fan, J [Virtua Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    utilized for tumor margin design and motion management in in conventional linac-based treatments.

  15. SU-E-T-150: End to End Tests On the First Clinical EDGETM

    Energy Technology Data Exchange (ETDEWEB)

    Scheib, S; Schmelzer, P [Varian Medical Systems, Baden - Daettwil (Switzerland); Vieira, S; Greco, C [Champalimaud Foundation, Lisbon (Portugal)

    2014-06-01

    Purpose: To quantify the sub millimeter overall accuracy of EDGETM, the dedicated linac based SRS/SABR treatment platform from Varian, using a novel End-to-End (E2E) test phantom. Methods: The new E2E test phantom developed by Varian consists of a cube with an outer dimension of 15x15x15 cm3. The phantom is equipped with an exchangable inner cube (7×7×7 cm3) to hold radiochromic films or a tungsten ball (diameter = 5 mm) for Winston-Lutz tests. 16 ceramic balls (diameter = 5 mm) are embedded in the outer cube. Three embedded Calypso transponders allow for Calypso based monitoring. The outer surface of the phantom is tracked using the Optical Surface Monitoring System (OSMS). The phantom is positioned using kV, MV and CBCT images. A simCT of the phantom was acquired and SRS/SABR plans were treated using the new phantom on the first clinical installed EDGETM. As a first step a series of EPID based Winston-Lutz tests have been performed. As a second step the calculated dose distribution applied to the phantom was verified with radiochromic films in orthogonal planes. The measured dose distribution is compared with the calculated (Eclipse) one based on the known isocenter on both dose distributions. The geometrical shift needed to match both dose distributions is the overall accuracy and is determined using dose profiles, isodose lines or gamma pass rates (3%, 1 mm). Results: Winston-Lutz tests using the central tungsten BB demonstrated a targeting accuracy of 0.44±0.18mm for jaw (2cm × 2cm) defined 0.39±0.19mm for MLC (2cm × 2cm) defined and 0.37±0.15mm for cone (12.5 mm) defined fields. A treated patient plan (spinal metastases lesion with integrated boost) showed a dosimetric dose localization accuracy of 0.6mm. Conclusion: Geometric and dosimetric E2E tests on EDGETM, show sub-millimeter E2E targeting and dose localisation accuracy.

  16. A prediction model of radiation-induced necrosis for intracranial radiosurgery based on target volume.

    Science.gov (United States)

    Zhao, Bo; Wen, Ning; Chetty, Indrin J; Huang, Yimei; Brown, Stephen L; Snyder, Karen C; Siddiqui, Farzan; Movsas, Benjamin; Siddiqui, M Salim

    2017-08-01

    This study aims to extend the observation that the 12 Gy-radiosurgical-volume (V12Gy) correlates with the incidence of radiation necrosis in patients with intracranial tumors treated with radiosurgery by using target volume to predict V12Gy. V12Gy based on the target volume was used to predict the radiation necrosis probability (P) directly. Also investigated was the reduction in radiation necrosis rates (ΔP) as a result of optimizing the prescription isodose lines for linac-based SRS. Twenty concentric spherical targets and 22 patients with brain tumors were retrospectively studied. For each case, a standard clinical plan and an optimized plan with prescription isodose lines based on gradient index were created. V12Gy were extracted from both plans to analyze the correlation between V12Gy and target volume. The necrosis probability P as a function of V12Gy was evaluated. To account for variation in prescription, the relation between V12Gy and prescription was also investigated. A prediction model for radiation-induced necrosis was presented based on the retrospective study. The model directly relates the typical prescribed dose and the target volume to the radionecrosis probability; V12Gy increased linearly with the target volume (R(2)  > 0.99). The linear correlation was then integrated into a logistic model to predict P directly from the target volume. The change in V12Gy as a function of prescription was modeled using a single parameter, s (=-1.15). Relatively large ΔP was observed for target volumes between 7 and 28 cm(3) with the maximum reduction (8-9%) occurring at approximately 18 cm(3) . Based on the model results, optimizing the prescription isodose line for target volumes between 7 and 28 cm(3) results in a significant reduction in necrosis probability. V12Gy based on the target volume could provide clinicians a predictor of radiation necrosis at the contouring stage thus facilitating treatment decisions. © 2017 American Association of

  17. Active Interrogation using Photofission Technique for Nuclear Materials Control and Accountability

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haori [Oregon State Univ., Corvallis, OR (United States)

    2016-03-31

    Innovative systems with increased sensitivity and resolution are in great demand to detect diversion and to prevent misuse in support of nuclear materials management for the U.S. fuel cycle. Nuclear fission is the most important multiplicative process involved in non-destructive active interrogation. This process produces the most easily recognizable signature for nuclear materials. In addition to thermal or high-energy neutrons, high-energy gamma rays can also excite a nucleus and cause fission through a process known as photofission. Electron linear accelerators (linacs) are widely used as the interrogating photon sources for inspection methods involving photofission technique. After photofission reactions, prompt signals are much stronger than the delayed signals, but it is difficult to quantify them in practical measurements. Delayed signals are easily distinguishable from the interrogating radiation. Linac-based, advanced inspection techniques utilizing the delayed signals after photofission have been extensively studied for homeland security applications. Previous research also showed that a unique delayed gamma ray energy spectrum exists for each fissionable isotope. In this work, high-energy delayed γ-rays were demonstrated to be signatures for detection, identification, and quantification of special nuclear materials. Such γ-rays were measured in between linac pulses using independent data acquisition systems. A list-mode system was developed to measure low-energy delayed γ-rays after irradiation. Photofission product yields of 238U and 239Pu were determined based on the measured delayed γ-ray spectra. The differential yields of delayed γ-rays were also proven to be able to discriminate nuclear from non-nuclear materials. The measurement outcomes were compared with Monte Carlo simulation results. It was demonstrated that the current available codes have capabilities and limitations in the simulation of photofission process. A two

  18. Dosimetric performance of the new high-definition multileaf collimator for intracranial stereotactic radiosurgery.

    Science.gov (United States)

    Dhabaan, Anees; Elder, Eric; Schreibmann, Eduard; Crocker, Ian; Curran, Walter J; Oyesiku, Nelson M; Shu, Hui-Kuo; Fox, Tim

    2010-06-21

    positive, indicating improvement, and ranging from 0.1 to 8.3 for normal tissue receiving 50% (NTV50), 70% (NTV70) and 90% (NTV90) of the prescription dose. The MLC2.5 has a dosimetric advantage over the MLC5 in Linac-based radiosurgery using DCA method for intracranial lesions, both in treatment conformity and normal tissue sparing when target shape complexity increases.

  19. Do technological advances in linear accelerators improve dosimetric outcomes in stereotaxy? A head-on comparison of seven linear accelerators using volumetric modulated arc therapy-based stereotactic planning

    Directory of Open Access Journals (Sweden)

    B Sarkar

    2016-01-01

    Full Text Available Introduction: Linear accelerator (Linac based stereotactic radiosurgery (SRS and stereotactic radiotherapy (SRT using volumetric modulated arc therapy (VMAT has been used for treating small intracranial lesions. Recent development in the Linacs such as inbuilt micro multileaf collimator (MLC and flattening filter free (FFF beam are intended to provide a better dose conformity and faster delivery when using VMAT technique. This study was aimed to compare the dosimetric outcomes and monitor units (MUs of the stereotactic treatment plans for different commercially available MLC models and beam profiles. Materials and Methods: Ten patients having 12 planning target volume (PTV/gross target volume's (GTVs who received the SRS/SRT treatment in our clinic using Axesse Linac (considered reference arm gold standard were considered for this study. The test arms comprised of plans using Elekta Agility with FFF, Elekta Agility with the plane beam, Elekta APEX, Varian Millennium 120, Varian Millennium 120HD, and Elekta Synergy in Monaco treatment planning system. Planning constraints and calculation grid spacing were not altered in the test plans. To objectively evaluate the efficacy of MLC-beam model, the resultant dosimetric outcomes were subtracted from the reference arm parameters. Results: V95%, V100%, V105%, D1%, maximum dose, and mean dose of PTV/GTV showed a maximum inter MLC - beam model variation of 1.5% and 2% for PTV and GTV, respectively. Average PTV conformity index and heterogeneity index shows a variation in the range 0.56–0.63 and 1.08–1.11, respectively. Mean dose difference (excluding Axesse for all organs varied between 1.1 cGy and 74.8 cGy (mean dose = 6.1 cGy standard deviation [SD] = 26.9 cGy and 1.7 cGy–194.5 cGy (mean dose 16.1 cGy SD = 57.2 cGy for single and multiple fraction, respectively. Conclusion: The dosimetry of VMAT-based SRS/SRT treatment plan had minimal dependence on MLC and beam model variations. All tested MLC

  20. Novel technique for high-precision stereotactic irradiation of mouse brains

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, J.; Woelfelschneider, J.; Derer, A.; Fietkau, R.; Gaipl, U.S.; Bert, C.; Frey, B. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Department of Radiation Oncology, Universitaetsklinikum Erlangen, Erlangen (Germany); Stache, C.; Buslei, R.; Hoelsken, A. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Institute of Neuropathology, Universitaetsklinikum Erlangen, Erlangen (Germany); Schwarz, M.; Baeuerle, T. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Institute of Radiology, Preclinical Imaging Platform Erlangen (PIPE), Universitaetsklinikum Erlangen, Erlangen (Germany)

    2016-11-15

    Small animal irradiation systems were developed for preclinical evaluation of tumor therapy closely resembling the clinical situation. Mostly only clinical LINACs are available, so protocols for small animal partial body irradiation using a conventional clinical system are essential. This study defines a protocol for conformal brain tumor irradiations in mice. CT and MRI images were used to demarcate the target volume and organs at risk. Three 6 MV photon beams were planned for a total dose of 10 fractions of 1.8 Gy. The mouse position in a dedicated applicator was verified by an X-ray patient positioning system before each irradiation. Dosimetric verifications (using ionization chambers and films) were performed. Irradiation-induced DNA damage was analyzed to verify the treatment effects on the cellular level. The defined treatment protocol and the applied fractionation scheme were feasible. The in-house developed applicator was suitable for individual positioning at submillimeter accuracy of anesthetized mice during irradiation, altogether performed in less than 10 min. All mice tolerated the treatment well. Measured dose values perfectly matched the nominal values from treatment planning. Cellular response was restricted to the target volume. Clinical LINAC-based irradiations of mice offer the potential to treat orthotopic tumors conformably. Especially with respect to lateral penumbra, dedicated small animal irradiation systems exceed the clinical LINAC solution. (orig.) [German] Kleintierbestrahlungsanlagen wurden entwickelt um praeklinische Studien in der Tumortherapie unter moeglichst klinischen Bedingungen durchzufuehren. Da an den meisten Instituten nur klinische LINACs zur Verfuegung stehen, werden Standardprotokolle zur Kleintierbestrahlung benoetigt, die konventionelle Systeme nutzen. In dieser Studie wird ein solches Protokoll fuer tumorkonforme Hirnbestrahlung von Maeusen definiert. CT- und MRT-Bilder wurden aufgenommen, um Zielvolumen und

  1. Plan Quality and Treatment Efficiency for Radiosurgery to Multiple Brain Metastases: Non-Coplanar RapidArc vs Gamma Knife

    Directory of Open Access Journals (Sweden)

    Haisong eLiu

    2016-02-01

    Full Text Available Objectives: This study compares the dosimetry and efficiency of two modern radiosurgery (SRS modalities for multiple brain metastases (Gamma Knife and LINAC-based RapidArc/volumetric modulated arc therapy, with a special focus on the comparison of low dose spread.Methods: Six patients with three or four small brain metastases were used in this study. The size of targets varied from 0.1 ~ 10.5 cc. SRS doses were prescribed according to size of lesions. SRS plans were made using both Gamma Knife® Perfexion and a single-isocenter, multiple non-coplanar RapidArc®. Dosimetric parameters analyzed included RTOG conformity index (CI, gradient index (GI, 12 Gy isodose volume (V12Gy for each target, and the dose spread (Dspread for each plan. Dspread reflects SRS plan’s capability of confining radiation to within the local vicinity of the lesion and to not spread out to the surrounding normal brain tissues. Each plan has a dose (Dspread, such that once dose decreases below Dspread (on total tissue DVH, isodose volume starts increasing dramatically. Dspread is defined as that dose when volume increase first exceeds 20 cc per 0.1 Gy dose decrease. Results: RapidArc SRS has smaller CI (1.19 ±0.14 vs. 1.50 ± 0.16, p<0.001 and larger GI (4.77 ± 1.49 vs. 3.65 ± 0.98, p <0.01. V12Gy results were comparable (2.73 ± 1.38 cc vs. 3.06 ± 2.20 cc, p = 0.58. Moderate to lower dose spread, V6, V4.5, and V3, were also equivalent. Gamma Knife plans achieved better very low dose spread (≤3 Gy and also had slightly smaller Dspread, 1.9 Gy vs 2.5 Gy. Total treatment time for Gamma Knife is estimated between 60~100 min. Gamma Knife treatments are between 3~5 times longer compared to RapidArc treatment techniques.Conclusion: Dosimetric parameters reflecting prescription dose conformality (CI, dose fall off (GI, radiation necrosis indicator (V12Gy, and dose spread (Dspread were compared between Gamma Knife SRS and RapidArc SRS for multi-mets. RapidArc plans have

  2. Is high–dose rate RapidArc-based radiosurgery dosimetrically advantageous for the treatment of intracranial tumors?

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Bo; Yang, Yong, E-mail: yangy2@upmc.edu; Li, Xiang; Li, Tianfang; Heron, Dwight E.; Saiful Huq, M.

    2015-04-01

    In linac-based stereotactic radiosurgery (SRS) and radiotherapy (SRT), circular cone(s) or conformal arc(s) are conventionally used to treat intracranial lesions. However, when the target is in close proximity to critical structures, it is frequently quite challenging to generate a quality plan using these techniques. In this study, we investigated the dosimetric characteristics of using high–dose rate RapidArc (RA) technique for radiosurgical treatment of intracranial lesions. A total of 10 intracranial SRS/SRT cases previously planned using dynamic conformal arc (DCA) or cone-based techniques have been included in this study. For each case, 3 treatment plans were generated: (1) a DCA plan with multiple noncoplanar arcs, (2) a high–dose rate RA plan with arcs oriented the same as DCA (multiple-arc RA), and 3) a high–dose rate RA plan with a single coplanar arc (single-arc RA). All treatment plans were generated under the same prescription and similar critical structure dose limits. Plan quality for different plans was evaluated by comparing various dosimetric parameters such as target coverage, conformity index (CI), homogeneity index (HI), critical structures, and normal brain tissue doses as well as beam delivery time. With similar critical structure sparing, high–dose rate RA plans can achieve much better target coverage, dose conformity, and dose homogeneity than the DCA plans can. Plan quality indices CI and HI, for the DCA, multiple-arc RA, and single-arc RA techniques, were measured as 1.67 ± 0.39, 1.32 ± 0.28, and 1.38 ± 0.30 and 1.24 ± 0.11, 1.10 ± 0.04, and 1.12 ± 0.07, respectively. Normal brain tissue dose (V{sub 12} {sub Gy}) was found to be similar for DCA and multiple-arc RA plans but much larger for the single-arc RA plans. Beam delivery was similar for DCA and multiple-arc RA plans but shorter with single-arc RA plans. Multiple-arc RA SRS/SRT can provide better treatment plans than conventional DCA plans, especially for complex cases.

  3. High energy photon reference for radiation protection: technical design of the LINAC beam and ionization chambers; and calculation of monoenergetic conversion coefficients

    Science.gov (United States)

    Dusciac, D.; Bordy, J.-M.; Daures, J.; Blideanu, V.

    2016-09-01

    In this work, we present the results of the first part of a research project aimed at offering a complete response to dosimeters providers and nuclear physicists' demands for high-energy (6 - 9 MeV) photon beams for radiation protection purposes. Classical facilities allowing the production of high-energy photonic radiation (proton accelerators, nuclear reactors) are very rare and need large investment for development and use. A novel solution is proposed, consisting in the use of a medical linear accelerator, allowing a significant decrease of all costs.Using Monte Carlo simulations (MCNP5 and PENELOPE codes), a specifically designed electron-photon conversion target allowing for obtaining a high energy photon beam (with an average energy weighted by fluence of about 6 MeV) has been built for radiation protection purposes. Due to the specific design of the target, this "realistic" radiation protection high-energy photon beam presents a uniform distribution of air kerma rate at a distance of 1 m, over a 30 × 30 cm2 surface. Two graphite cavity ionizing chambers for ionometric measurements have been built. For one of these chambers, the charge collection volume has been measured allowing for its use as a primary standard. The second ionizing chamber is used as a transfer standard; as such it has been calibrated in a 60Co beam, and in the high energy photon beam for radiation protection.The measurements with these ionizing chambers allowed for an evaluation of the air kerma rate in the LINAC based high-energy photon beam for radiation protection: the values cover a range between 36 mGy/h and 210 mGy/h, compatible with radiation protection purposes.Finally, using Monte Carlo simulations, conversion coefficients from air kerma to dose equivalent quantities have been calculated in the range between 10 keV and 22.4 MeV, for the spectral distribution of the fluence corresponding to the beam produced by the linear accelerator of the LNE-LNHB.

  4. On-site Real-Time Inspection System for Pump-impeller using X-band Linac X-ray Source

    Science.gov (United States)

    Yamamoto, Tomohiko; Natsui, Takuya; Taguchi, Hiroki; Taniguchi, Yoshihiro; Lee, Ki woo; Hashimoto, Eiko; Sakamoto, Fumito; Sakumi, Akira; Yusa, Noritaka; Uesaka, Mitsuru; Nakamura, Naoki; Yamamoto, Masashi; Tanabe, Eiji

    2009-03-01

    The methods of nondestructive testing (NDT) are generally ultrasonic, neutron, eddy-current and X-rays, NDT by using X-rays, in particular, is the most useful inspection technique having high resolution. We can especially evaluate corroded pipes of petrochemical complex, nuclear and thermal-power plants by the high energy X-ray NDT system. We develop a portable X-ray NDT system with X-band linac and magnetron. This system can generate a 950 keV electron beam. We are able to get X-ray images of samples with 1 mm spatial resolution. This system has application to real time impeller inspection because linac based X-ray sources are able to generate pulsed X-rays. So, we can inspect the rotating impeller if the X-ray pulse rate is synchronized with the impeller rotation rate. This system has application in condition based maintenance (CBM) of nuclear plants, for example. However, 950 keV X-ray source can only be used for thin tubes with 20 mm thickness. We have started design of a 3.95 MeV X-band linac for broader X-ray NDT application. We think that this X-ray NDT system will be useful for corrosion wastage and cracking in thicker tubes at nuclear plants and impeller of larger pumps. This system consists of X-band linac, thermionic cathode electron gun, magnetron and waveguide components. For achieving higher electric fields the 3.95 MeV X-band linac structure has the side-coupled acceleration structure. This structure has more efficient acceleration than the 950 keV linac with alternating periodic structure (APS). We adopt a 1.3 MW magnetron for the RF source. This accelerator system is about 30 cm long. The beam current is about 150 mA, and X-ray dose rate is 10 Gy@1 m/500 pps. In this paper, the detail of the whole system concept and the electromagnetic field of designed linac structure will be reported.

  5. High energy photon reference for radiation protection: technical design of the LINAC beam and ionization chambers; and calculation of monoenergetic conversion coefficients

    Directory of Open Access Journals (Sweden)

    Dusciac D.

    2016-01-01

    Full Text Available In this work, we present the results of the first part of a research project aimed at offering a complete response to dosimeters providers and nuclear physicists’ demands for high-energy (6 – 9 MeV photon beams for radiation protection purposes. Classical facilities allowing the production of high-energy photonic radiation (proton accelerators, nuclear reactors are very rare and need large investment for development and use. A novel solution is proposed, consisting in the use of a medical linear accelerator, allowing a significant decrease of all costs.Using Monte Carlo simulations (MCNP5 and PENELOPE codes, a specifically designed electron-photon conversion target allowing for obtaining a high energy photon beam (with an average energy weighted by fluence of about 6 MeV has been built for radiation protection purposes. Due to the specific design of the target, this “realistic” radiation protection high-energy photon beam presents a uniform distribution of air kerma rate at a distance of 1 m, over a 30 × 30 cm2 surface. Two graphite cavity ionizing chambers for ionometric measurements have been built. For one of these chambers, the charge collection volume has been measured allowing for its use as a primary standard. The second ionizing chamber is used as a transfer standard; as such it has been calibrated in a 60Co beam, and in the high energy photon beam for radiation protection.The measurements with these ionizing chambers allowed for an evaluation of the air kerma rate in the LINAC based high-energy photon beam for radiation protection: the values cover a range between 36 mGy/h and 210 mGy/h, compatible with radiation protection purposes.Finally, using Monte Carlo simulations, conversion coefficients from air kerma to dose equivalent quantities have been calculated in the range between 10 keV and 22.4 MeV, for the spectral distribution of the fluence corresponding to the beam produced by the linear accelerator of the LNE-LNHB.

  6. Plan quality and treatment planning technique for single isocenter cranial radiosurgery with volumetric modulated arc therapy.

    Science.gov (United States)

    Clark, Grant M; Popple, Richard A; Prendergast, Brendan M; Spencer, Sharon A; Thomas, Evan M; Stewart, John G; Guthrie, Barton L; Markert, James M; Fiveash, John B

    2012-01-01

    To demonstrate plan quality and provide a practical, systematic approach to the treatment planning technique for single isocenter cranial radiosurgery with volumetric modulated arc therapy (VMAT; RapidArc, Varian Medical systems, Palo Alto, CA). Fifteen patients with 1 or more brain metastases underwent single isocenter VMAT radiosurgery. All plans were normalized to deliver 100% of the prescription dose to 99%-100% of the target volume. All targets per plan were treated to the same dose. Plans were created with dose control tuning structures surrounding targets to maximize conformity and dose gradient. Plan quality was evaluated by calculation of conformity index (CI = 100% isodose volume/target volume) and homogeneity index (HI = maximum dose/prescription dose) scores for each target and a Paddick gradient index (GI = 50% isodose volume/100% isodose volume) score for each plan. The median number of targets per patient was 2 (range, 1-5). The median number of non-coplanar arcs utilized per plan was 2 (range, 1- 4). Single target plans were created with 1 or 2 non-coplanar arcs while multitarget plans utilized 2 to 4 non-coplanar arcs. Prescription doses ranged from 5-16 Gy in 1-5 fractions. The mean conformity index was 1.12 (± SD, 0.13) and the mean HI was 1.44 (± SD, 0.11) for all targets. The mean GI per plan was 3.34 (± SD, 0.42). We have outlined a practical approach to cranial radiosurgery treatment planning using the single isocenter VMAT platform. One or 2 arc single isocenter plans are often adequate for treatment of single targets, while 2-4 arcs may be more advantageous for multiple targets. Given the high plan quality and extreme clinical efficiency, this single isocenter VMAT approach will continue to become more prevalent for linac-based radiosurgical treatment of 1 or more intracranial targets and will likely replace multiple isocenter techniques. Copyright © 2012 American Society for Radiation Oncology. Published by Elsevier Inc. All rights

  7. MO-AB-BRA-03: Calorimetry-Based Absorbed Dose to Water Measurements Using Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Martinez, E; Malin, M; DeWerd, L [University of WI-Madison/ADCL, Madison, WI (United States)

    2015-06-15

    Purpose: Interferometry-based calorimetry is a novel technique to measure radiation-induced temperature changes allowing the measurement of absorbed dose to water (ADW). There are no mechanical components in the field. This technique also has the possibility of obtaining 2D dose distributions. The goal of this investigation is to calorimetrically-measure doses between 2.5 and 5 Gy over a single projection in a photon beam using interferometry and compare the results with doses calculated using the TG-51 linac calibration. Methods: ADW was determined by measuring radiation-induced phase shifts (PSs) of light passing through water irradiated with a 6 MV photon beam. A 9×9×9 cm{sup 3} glass phantom filled with water and placed in an arm of a Michelson interferometer was irradiated with 300, 400, 500 and 600 monitor units. The whole system was thermally insulated to achieve sufficient passive temperature control. The depth of measurement was 4.5 cm with a field size of 7×7 cm{sup 2}. The intensity of the fringe pattern was monitored with a photodiode and used to calculate the time-dependent PS curve. Data was acquired 60 s before and after the irradiation. The radiation-induced PS was calculated by taking the difference in the pre- and post-irradiation drifts extrapolated to the midpoint of the irradiation. Results were compared to computed doses. Results: Average comparison of calculated ADW values with interferometry-measured values showed an agreement to within 9.5%. k=1 uncertainties were 4.3% for calculations and 14.7% for measurements. The dominant source of uncertainty for the measurements was a temperature drift of about 30 µK/s caused by heat conduction from the interferometer’s surroundings. Conclusion: This work presented the first absolute ADW measurements using interferometry in the dose range of linac-based radiotherapy. Future work to improve measurements’ reproducibility includes the implementation of active thermal control techniques.

  8. SU-D-BRA-02: Motion Assessment During Open Face Mask SRS Using CBCT and Surface Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Williams, BB; Fox, CJ; Hartford, AC; Gladstone, DJ [Dartmouth-Hitchcock Medical Center, Lebanon, NH (Lebanon)

    2016-06-15

    Purpose: To assess the robustness of immobilization using open-face mask technology for linac-based stereotactic radiosurgery (SRS) with multiple non-coplanar arcs via repeated CBCT acquisition, with comparison to contemporaneous optical surface tracking data. Methods: 25 patients were treated in open faced masks with cranial SRS using 3–4 non-coplanar arcs. Repeated CBCT imaging was performed to verify the maintenance of proper patient positioning during treatment. Initial patient positioning was performed based on prescribed shifts and optical surface tracking. Positioning refinements employed rigid 3D-matching of the planning CT and CBCT images and were implemented via automated 6DOF couch control. CBCT imaging was repeated following the treatment of all non-transverse beams with associated couch kicks. Detected patient translations and rotations were recorded and automatically corrected. Optical surface tracking was applied throughout the treatments to monitor motion, and this contemporaneous patient positioning data was recorded to compare against CBCT data and 6DOF couch adjustments. Results: Initial patient positions were refined on average by translations of 3±1mm and rotations of ±0.9-degrees. Optical surface tracking corroborated couch corrections to within 1±1mm and ±0.4-degrees. Following treatment of the transverse and subsequent superior-oblique beam, average translations of 0.6±0.4mm and rotations of ±0.4-degrees were reported via CBCT, with optical surface tracking in agreement to within 1.1±0.6mm and ±0.6-degrees. Following treatment of the third beam, CBCT indicated additional translations of 0.4±0.2mm and rotations of ±0.3-degrees. Cumulative couch corrections resulted in 0.7 ± 0.4mm average magnitude translations and rotations of ±0.4-degrees. Conclusion: Based on CBCT measurements of patients during SRS, the open face mask maintained patient positioning to within 1.5mm and 1-degree with >95% confidence. Patient positioning

  9. [Radiosurgery of the brain at the beginning of the 21st century: gamma knife with C-table].

    Science.gov (United States)

    Szeifert, G; Levivier, M; Kondziolka, D; Lunsford, D; Brotchi, J; Nyáry, I

    2001-10-07

    The goal of stereotactic radiosurgery by definition is "the delivery of a single, high dose of radiation allowing the precise and complete destruction of chosen target structures containing healthy and/or pathological cells, without significant concomitant or late radiation damage to adjacent tissues". This effect is obtained by the precise focusing of multiple low energy radiation beams crossing at the target. Three different techniques can be used for radiosurgery: linear accelerator (LINAC) based radiosurgery, Bragg-peak (proton) therapy and Gamma Knife radiosurgery. Leksell Gamma Knife (LGK) is a dedicated neurosurgical device for brain surgery to destroy predetermined intracranial targets through the intact skull. It operates via the radiobiological effect of stereotactically directed, highly focused ionizing gamma-beams of 201 cobalt-60 sources. The LGK offers the best precision of target during irradiation. The mechanical accuracy is about 0.3 mm, which makes it particularly suitable for highly sophisticated neurosurgical interventions. Radiosurgery was originally developed to treat functional neurological disorders, but soon after its introduction cerebral arteriovenous malformations, and brain tumors became the main targets for the technique. Since the first LGK installation at the Sophiahemmet Hospital, Stockholm, Sweden in 1967, over 150,000 patients have already been treated in more than 150 units worldwide. The accumulated clinical experience with the LGK has established this method as the "golden standard" of radiosurgery. In December 1999, a new development, the LGK Model-C was installed at the Centre Gamma Knife, Université Libre de Bruxelles, Hôpital Académique Erasme, Brussels, Belgium. This was followed by completion of two similar units in Krefeld, Germany, and at the Presbyterian University Hospital, Pittsburgh, Pennsylvania, U.S.A. The major innovation in the design of the LGK Model-C is the robotic Automatic Positioning System, which

  10. Heuristic knowledge-based planning for single-isocenter stereotactic radiosurgery to multiple brain metastases.

    Science.gov (United States)

    Ziemer, Benjamin P; Sanghvi, Parag; Hattangadi-Gluth, Jona; Moore, Kevin L

    2017-07-21

    Single-isocenter, volumetric-modulated arc therapy (VMAT) stereotactic radiosurgery (SRS) for multiple brain metastases (multimets) can deliver highly conformal dose distributions and reduce overall patient treatment time compared to other techniques. However, treatment planning for multimet cases is highly complex due to variability in numbers and sizes of brain metastases, as well as their relative proximity to organs-at-risk (OARs). The purpose of this study was to automate the VMAT planning of multimet cases through a knowledge-based planning (KBP) approach that adapts single-target SRS dose predictions to multiple target predictions. Using a previously published artificial neural network (ANN) KBP system trained on single-target, linac-based SRS plans, 3D dose distribution predictions for multimet patients were obtained by treating each brain lesion as a solitary target and subsequently combining individual dose predictions into a single distribution. Spatial dose distributions di(r→) for each of the i = 1…N lesions were merged using the combination function d(r→)=∑iNdin(r→)1/n. The optimal value of n was determined by minimizing root-mean squared (RMS) difference between clinical multimet plans and predicted dose per unit length along the line profile joining each lesion in the clinical cohort. The gradient measure GM=[3/4π]1/3V50%1/3-V100%1/3 is the primary quality metric for SRS plan evaluation at our institution and served as the main comparative metric between clinical plans and the KBP results. A total of 41 previously treated multimet plans, with target numbers ranging from N = 2-10, were used to validate the ANN predictions and subsequent KBP auto-planning routine. Fully deliverable KBP plans were developed by converting predicted dose distribution into patient-specific optimization objectives for the clinical treatment planning system (TPS). Plan parity was maintained through identical arc configuration and target normalization. Overall

  11. Hyperthermically induced changes in high spectral and spatial resolution MR images of tumor tissue—a pilot study

    Science.gov (United States)

    Foxley, Sean; Fan, Xiaobing; River, Jonathan; Zamora, Marta; Markiewicz, Erica; Sokka, Shunmugavelu; Karczmar, Gregory S.

    2012-05-01

    This pilot study investigated the feasibility of using MRI based on BOLD (blood-oxygen-level-dependent) contrast to detect physiological effects of locally induced hyperthermia in a rodent tumor model. Nude mice bearing AT6.1 rodent prostate tumors inoculated in the hind leg were imaged using a 9.4 T scanner using a multi-gradient echo pulse sequence to acquire high spectral and spatial resolution (HiSS) data. Temperature increases of approximately 6 °C were produced in tumor tissue using fiber-optic-guided light from a 250 W halogen lamp. HiSS data were acquired over three slices through the tumor and leg both prior to and during heating. Water spectra were produced from these datasets for each voxel at each time point. Time-dependent changes in water resonance peak width were measured during 15 min of localized tumor heating. The results demonstrated that hyperthermia produced both significant increases and decreases in water resonance peak width. Average decreases in peak width were significantly larger in the tumor rim than in normal muscle (p = 0.04). The effect of hyperthermia in tumor was spatially heterogeneous, i.e. the standard deviation of the change in peak width was significantly larger in the tumor rim than in normal muscle (p = 0.005). Therefore, mild hyperthermia produces spatially heterogeneous changes in water peak width in both tumor and muscle. This may reflect heterogeneous effects of hyperthermia on local oxygenation. The peak width changes in tumor and muscle were significantly different, perhaps due to abnormal tumor vasculature and metabolism. Response to hyperthermia measured by MRI may be useful for identifying and/or characterizing suspicious lesions as well as guiding the development of new hyperthermia protocols.

  12. Localizing the VHE γ-ray source at the Galactic Centre

    Science.gov (United States)

    Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Braun, I.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Conrad, J.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'c.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fiasson, A.; Förster, A.; Fontaine, G.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Keogh, D.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Marandon, V.; Martineau-Huynh, O.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Orford, K. J.; Ostrowski, M.; Panter, M.; Arribas, M. Paz; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Reimer, O.; Renaud, M.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schönwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Superina, G.; Sushch, I.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.; H.E.S.S. Collaboration

    2010-03-01

    The inner 10pc of our Galaxy contains many counterpart candidates of the very high energy (VHE; >100GeV) γ-ray point source HESS J1745-290. Within the point spread function of the H.E.S.S. measurement, at least three objects are capable of accelerating particles to VHE and beyond and of providing the observed γ-ray flux. Previous attempts to address this source confusion were hampered by the fact that the projected distances between these objects were of the order of the error circle radius of the emission centroid (34arcsec, dominated by the pointing uncertainty of the H.E.S.S. instrument). Here we present H.E.S.S. data of the Galactic Centre region, recorded with an improved control of the instrument pointing compared to H.E.S.S. standard pointing procedures. Stars observed during γ-ray observations by optical guiding cameras mounted on each H.E.S.S. telescope are used for off-line pointing calibration, thereby decreasing the systematic pointing uncertainties from 20 to 6arcsec per axis. The position of HESS J1745-290 is obtained by fitting a multi-Gaussian profile to the background-subtracted γ-ray count map. A spatial comparison of the best-fitting position of HESS J1745-290 with the position and morphology of candidate counterparts is performed. The position is, within a total error circle radius of 13arcsec, coincident with the position of the supermassive black hole Sgr A* and the recently discovered pulsar wind nebula candidate G359.95-0.04. It is significantly displaced from the centroid of the supernova remnant Sgr A East, excluding this object with high probability as the dominant source of the VHE γ-ray emission.

  13. Intra-operative airway management in patients with maxillofacial trauma having reduction and immobilization of facial fractures

    Directory of Open Access Journals (Sweden)

    Babatunde Babasola Osinaike

    2015-01-01

    Full Text Available Background: Despite advancements in airway management, treatment of fractures in the maxillofacial region under general anesthesia remains a unique anesthetic challenge. We reviewed the pattern of airway management in patients with maxillofacial fractures and assessed those challenges associated with the different airway management techniques employed. Materials and Methods: The anesthetic chart, theatre and maxillofacial operations records of patients who had reduction and immobilization of various maxillofacial fractures over a 2-year period were reviewed. Information obtained included the patient demographics, mechanisms of injury, types of fractures and details about airway management. Statistical Package for Social Sciences, SPSS version 17.0 was utilized for all data analysis. Results: Fifty-one patients were recruited during the 2-year study period. Mask ventilation was easy in 80-90% of the patients, 80% had Mallampati three or four, while 4 (7.8% had laryngoscopy grading of 4. There was no statistically significant difference between the fracture groups in terms of the laryngoscopy grading (P = 0.153 but there was statistical significant difference in the technique of airway management (P = 0.0001. Nasal intubation following direct laryngoscopy was employed in 64.7% of the patients, fiber-optic guided nasal intubation was utilized in only 7.8%. None of the patients had tracheostomy either before or during operative management. Conclusion: Laryngoscopic grading and not adequacy of mouth opening predicted difficult intubation in this group of patients in the immediate preoperative period. Despite the distortions in the anatomy of the upper airway that may result from maxillofacial fractures, nasal intubation following direct laryngoscopy may be possible in many patients with maxillofacial fractures.

  14. A proposal for digital electro-optic switches with free-carrier dispersion effect and Goos-Hanchen shift in silicon-on-insulator waveguide corner mirror

    Science.gov (United States)

    Sun, DeGui

    2013-09-01

    In a silicon-on-insulator (SOI) waveguide corner mirror (WCM) structure, with the quantum process of a frustrated total internal reflection (FTIR) phenomenon and the time delay principle in the two-dimensional potential barrier tunneling process of a mass of particles, we derive an accurate physical model for the Goos-Hanchen (GH) shift of optical guided-mode in the FTIR process, and in principle match the GH shift jumping states with the independent guided-modes. Then, we propose and demonstrate a new regime of 1 × N digital optical switches with a matching state between the free-carrier dispersion (FCD) based refractive index modulation (RIM) of silicon to create a GH shift jumping function of a photonic signal at the reflecting interface and the independent guided-modes in the FTIR process, where a MOS-capacitor type electro-optic modulation regime is proposed and discussed to realize an effective FCD-based RIM. At the critical matching state, i.e., the incident of an optical beam is at the vicinity of Brewster angle in the WCM, a mini-change of refractive index of waveguide material can cause a great jump of GH shift along the FTIR reflecting interface, and further a 1 × N digital optical switching process could be realized. For a 350-500 nm single-mode rib waveguide made on the 220 nm CMOS-compatible SOI substrate and with the FCD effect based RIM of silicon crystal, a concentration variation of 1018-1019 cm-3 has caused a 0.5-2.5 μm GH shift of reflected beam, which is at 2-5 times of a mode-size and hence radically convinces an optical switching function with a 1 × 3-1 × 10 scale.

  15. Theory of the ion-channel laser

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, D.H.

    1990-09-01

    A relativistic electron beam propagating through a plasma in the ion-focussed regime exhibits an electromagnetic instability with peak growth rate near a resonant frequency {omega}{approximately}2 {gamma}{sup 2} {omega}{beta}, where {gamma} is the Lorentz factor and {omega}{beta} is the betatron frequency. The physical basis for this instability is that an ensemble of relativistic simple harmonic oscillators, weakly driven by an electromagnetic wave, will lose energy to the wave through axial bunching. This bunching'' corresponds to the development of an rf component in the beam current, and a coherent centroid oscillation. The subject of this thesis is the theory of a laser capitalizing on this electromagnetic instability. A historical perspective is offered. The basic features of relativistic electron beam propagation in the ion-focussed regime are reviewed. The ion-channel laser (ICL) instability is explored theoretically through an eikonal formalism, analgous to the KMR'' formalism for the free-electron laser (FEL). The dispersion relation is derived, and the dependence of growth rate on three key parameters is explored. Finite temperature effects are assessed. From this work it is found that the typical gain length for amplification is longer than the Rayleigh length and we go on to consider three mechanisms which will tend to guide waveguide. First, we consider the effect of the ion channel as a dielectric waveguide. We consider next the use of a conducting waveguide, appropriate for a microwave amplifier. Finally, we examine a form of optical guiding'' analgous to that found in the FEL. The eikonal formalism is used to model numerically the instability through and beyond saturation. Results are compared with the numerical simulation of the full equations of motion, and with the analytic scalings. The analytical requirement on detuning spread is confirmed.

  16. Combined hostile fire and optics detection

    Science.gov (United States)

    Brännlund, Carl; Tidström, Jonas; Henriksson, Markus; Sjöqvist, Lars

    2013-10-01

    Snipers and other optically guided weapon systems are serious threats in military operations. We have studied a SWIR (Short Wave Infrared) camera-based system with capability to detect and locate snipers both before and after shot over a large field-of-view. The high frame rate SWIR-camera allows resolution of the temporal profile of muzzle flashes which is the infrared signature associated with the ejection of the bullet from the rifle. The capability to detect and discriminate sniper muzzle flashes with this system has been verified by FOI in earlier studies. In this work we have extended the system by adding a laser channel for optics detection. A laser diode with slit-shaped beam profile is scanned over the camera field-of-view to detect retro reflection from optical sights. The optics detection system has been tested at various distances up to 1.15 km showing the feasibility to detect rifle scopes in full daylight. The high speed camera gives the possibility to discriminate false alarms by analyzing the temporal data. The intensity variation, caused by atmospheric turbulence, enables discrimination of small sights from larger reflectors due to aperture averaging, although the targets only cover a single pixel. It is shown that optics detection can be integrated in combination with muzzle flash detection by adding a scanning rectangular laser slit. The overall optics detection capability by continuous surveillance of a relatively large field-of-view looks promising. This type of multifunctional system may become an important tool to detect snipers before and after shot.

  17. Using the Galileoscope in Public Outreach Programs In the United States and Chile

    Science.gov (United States)

    Sparks, Robert T.; Pompea, Stephen M.; Seguel, Juan C.; Munizaga, Daniel A.; Opazo, Leonor; Walker, Constance Elaine; Tresch Fienberg, Richard; Arion, Douglas N.

    2015-08-01

    The Galileoscope was developed by a team of educators, astronomers and optical engineers as one of the cornerstone projects for the International Year of Astronomy 2009 (IYA). Over 230,000 Galileoscopes have been distributed.The National Optical Astronomy Observatory (NOAO) has developed a variety of educational materials to accompany the Galileoscope. The Galileoscope Optics Guide contains a variety of experiments and demonstrations (adapted from the National Science Foundation funded Hands-On Optics program) to help students understand how a telescope focuses light and produces an image. The Teaching With Telescopes kit developed at NOAO contains a variety of materials teachers can use to teach about light and optics. The Teaching With Telescopes kit is a basis for teacher professional development. The Galileoscope Observing Guide (updated annually) contains a variety of observing tips and information on the best objects to observe with the Galileoscope.NOAO has used Galileoscopes in a wide variety of educational environments. NOAO received a grant from Science Foundation Arizona to bring the Hands-On Optics program to Boys and Girls Clubs in Arizona. All the Boys and Girls Clubs received Galileoscopes as part of the grant. Edelman Financial made a donation that allowed us to distribute 15,000 Galileoscopes to Project ASTRO sites, members of the National Earth Science Teacher’s Association and individual teachers. Science Foundation Arizona partnered with NOAO in the Arizona Galileoscope program to conduct star parties in Yuma, Flagstaff, Safford, Globe and Payson. NOAO partnered with Raytheon in the MathMovesU program to build Galileoscopes with over 2,000 students in Tucson. NOAO has used Galileoscopes in professional development workshops with teachers at meetings including the American Astronomical Society, the Astronomical Society of the Pacific, and the National Science Teachers Association.

  18. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults†

    Science.gov (United States)

    Frerk, C.; Mitchell, V. S.; McNarry, A. F.; Mendonca, C.; Bhagrath, R.; Patel, A.; O'Sullivan, E. P.; Woodall, N. M.; Ahmad, I.

    2015-01-01

    These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team. PMID:26556848

  19. Adaptive fractionated stereotactic Gamma Knife radiotherapy of meningioma using integrated stereotactic cone-beam-CT and adaptive re-planning (a-gkFSRT)

    Energy Technology Data Exchange (ETDEWEB)

    Stieler, F.; Wenz, F.; Abo-Madyan, Y.; Schweizer, B.; Polednik, M.; Herskind, C.; Giordano, F.A.; Mai, S. [University of Heidelberg, Department of Radiation Oncology, University Medical Center Mannheim, Mannheim (Germany)

    2016-11-15

    The Gamma Knife Icon (Elekta AB, Stockholm, Sweden) allows frameless stereotactic treatment using a combination of cone beam computer tomography (CBCT), a thermoplastic mask system, and an infrared-based high-definition motion management (HDMM) camera system for patient tracking during treatment. We report on the first patient with meningioma at the left petrous bone treated with adaptive fractionated stereotactic radiotherapy (a-gkFSRT). The first patient treated with Gamma Knife Icon at our institute received MR imaging for preplanning before treatment. For each treatment fraction, a daily CBCT was performed to verify the actual scull/tumor position. The system automatically adapted the planned shot positions to the daily position and recalculated the dose distribution (online adaptive planning). During treatment, the HDMM system recorded the intrafractional patient motion. Furthermore, the required times were recorded to define a clinical treatment slot. Total treatment time was around 20 min. Patient positioning needed 0.8 min, CBCT positioning plus acquisition 1.65 min, CT data processing and adaptive planning 2.66 min, and treatment 15.6 min. The differences for the five daily CBCTs compared to the reference are for rotation: -0.59 ± 0.49 /0.18 ± 0.20 /0.05 ± 0.36 and for translation: 0.94 ± 0.52 mm/-0.08 ± 0.08 mm/-1.13 ± 0.89 mm. Over all fractions, an intrafractional movement of 0.13 ± 0.04 mm was observed. The Gamma Knife Icon allows combining the accuracy of the stereotactic Gamma Knife system with the flexibility of fractionated treatment with the mask system and CBCT. Furthermore, the Icon system introduces a new online patient tracking system to the clinical routine. The interfractional accuracy of patient positioning was controlled with a thermoplastic mask and CBCT. (orig.) [German] Das Gamma Knife Icon (Elekta AB, Stockholm, Schweden) ermoeglicht die stereotaktische Behandlung von Patienten mittels Cone-beam-Computertomographie (CBCT

  20. Hypofractionated stereotactic radiotherapy of acoustic neuroma. Volume changes and hearing results after 89-month median follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Kranzinger, Manfred; Fastner, Gerd [Paracelsus Medical University Clinics (PMU), University Clinic of Radiotherapy and Radio-Oncology, Salzburg County Hospital, Salzburg (Austria); Zehentmayr, Franz; Sedlmayer, Felix [Paracelsus Medical University Clinics (PMU), University Clinic of Radiotherapy and Radio-Oncology, Salzburg County Hospital, Salzburg (Austria); Salzburg County Hospital, Paracelsus Medical University Clinics, radART - Institute for Research and Development on Advanced Radiation Technologies, Salzburg (Austria); Oberascher, Gerhard [Paracelsus Medical University Clinics (PMU), University Clinic of Ear, Nose and Throat Diseases, Salzburg County Hospital, Salzburg (Austria); Merz, Florian; Rahim, Hassan [Salzburg County Hospital, Paracelsus Medical University Clinics, Medical Radiation Protection Unit, Salzburg (Austria); Nairz, Olaf [Clinic Bad Trissl, Oberaudorf (Germany)

    2014-09-15

    The goal of this work was to evaluate toxicity and local control following hypofractionated stereotactic radiation treatment with special focus on changes in tumor volume and hearing capacity. In all, 29 patients with unilateral acoustic neuroma were treated between 2001 and 2007 within a prospective radiation protocol (7 x 4 Gy ICRU dose). Median tumor volume was 0.9 ml. Follow-up started at 6 months and was repeated annually with MRI volumetry and audiometry. Hearing preservation was defined as preservation of Class A/B hearing according to the guidelines of the American Academy of Otolaryngology (1995). No patient had any intervention after a median imaging follow-up of 89.5 months, one patient showed radiological progression. Transient increase of tumor volume developed in 17/29 patients, whereas 22/29 patients (75.9 %) presented with a volume reduction at last follow-up. A total of 21 patients were eligible for hearing evaluation. Mean pure tone average (PTA) deteriorated from 39.3 to 65.9 dB and mean speech discrimination score (SDS) dropped from 74.3 to 38.1 %. The 5-year actuarial Class A/B hearing preservation rate was 50.0 ± 14.4 %. Radiation increases only minimally, if at all, the hearing deterioration which emerges by observation alone. Presbyacusis is not responsible for this deterioration. Transient tumor enlargement is common. Today radiation of small- and medium-sized acoustic neuroma can be performed with different highly conformal techniques as fractionated treatment or single low-dose radiosurgery with equal results regarding tumor control, hearing preservation, and side effects. Hypofractionation is more comfortable for the patient than conventional regimens and represents a serious alternative to frameless radiosurgery. (orig.) [German] Ziel der Studie war die Evaluierung der Toxizitaet und der lokalen Tumorkontrolle einer hypofraktionierten stereotaktischen Bestrahlung mit besonderem Augenmerk auf Veraenderungen von Tumorvolumen und

  1. Design and Fabrication of Nereid-UI: A Remotely Operated Underwater Vehicle for Oceanographic Access Under Ice

    Science.gov (United States)

    Whitcomb, L. L.; Bowen, A. D.; Yoerger, D.; German, C. R.; Kinsey, J. C.; Mayer, L. A.; Jakuba, M. V.; Gomez-Ibanez, D.; Taylor, C. L.; Machado, C.; Howland, J. C.; Kaiser, C. L.; Heintz, M.; Pontbriand, C.; Suman, S.; O'hara, L.

    2013-12-01

    The Woods Hole Oceanographic Institution and collaborators from the Johns Hopkins University and the University of New Hampshire are developing for the Polar Science Community a remotely-controlled underwater robotic vehicle capable of being tele-operated under ice under remote real-time human supervision. The Nereid Under-Ice (Nereid-UI) vehicle will enable exploration and detailed examination of biological and physical environments at glacial ice-tongues and ice-shelf margins, delivering high-definition video in addition to survey data from on board acoustic, chemical, and biological sensors. Preliminary propulsion system testing indicates the vehicle will be able to attain standoff distances of up to 20 km from an ice-edge boundary, as dictated by the current maximum tether length. The goal of the Nereid-UI system is to provide scientific access to under-ice and ice-margin environments that is presently impractical or infeasible. FIBER-OPTIC TETHER: The heart of the Nereid-UI system is its expendable fiber optic telemetry system. The telemetry system utilizes many of the same components pioneered for the full-ocean depth capable HROV Nereus vehicle, with the addition of continuous fiber status monitoring, and new float-pack and depressor designs that enable single-body deployment. POWER SYSTEM: Nereid-UI is powered by a pressure-tolerant lithium-ion battery system composed of 30 Ah prismatic pouch cells, arranged on a 90 volt bus and capable of delivering 15 kW. The cells are contained in modules of 8 cells, and groups of 9 modules are housed together in oil-filled plastic boxes. The power distribution system uses pressure tolerant components extensively, each of which have been individually qualified to 10 kpsi and operation between -20 C and 40 C. THRUSTERS: Nereid-UI will employ eight identical WHOI-designed thrusters, each with a frameless motor, oil-filled and individually compensated, and designed for low-speed (500 rpm max) direct drive. We expect an end

  2. Optimizing brain tumor resection. Midfield interventional MR imaging.

    Science.gov (United States)

    Alexander, E

    2001-11-01

    using advanced navigational tools and computer technology, it represents an integration of frameless stereotactic methods with real-time interactive imaging. The midfield imager provides sufficient spatial and temporal resolution and image quality to assess anatomy and pathology adequately, to monitor a surgical procedure, and make image-based decisions. The intraoperative use of this unique system is not limited to biopsies or limited-access procedures. The entire range of neurosurgical procedures can be performed, if the requisite instrumentation is available. Much work remains to be done, however. The team did not develop this system only to enable the performance of current neurosurgical procedures. Forty years ago, the operating microscope enabled not only the performance of undreamt-of procedures but opened the door to entire new subspecialties. The entire landscape of neurosurgery will change at a fundamental level as the full ramifications of this exciting idea come to fruition. The holy grail of image-guided surgery is a seamless interface between the eye and hand in the purest sense (i.e., the mind's eye and hand). Ideally, this seamless interface represents effortless flow between the procedural goal compared with the present situation and the manipulation of the tools available to accomplish the task, whether they be the scalpel, drill, laser, ultrasonic aspirator, phased array focused ultrasound, microrobot, or high-dose irradiator. As in the realm of high-performance military jet fighters, the physical limits of the human being demarcate the confining boundary of the system. Those limits are much tighter around the domain of tool manipulation, where the surgeon will yield, early on, to the enhanced performance of robotics and other technical adjuncts. The era of large open magnet imaging systems for surgical procedures then will come to a close; however, the grander era of the surgeon's integration of precision-guided, multimodality therapeutics will just

  3. Pelvic nodal dose escalation with prostate hypofractionation using conformal avoidance defined (H-CAD) intensity modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Theodore S.; Tome, Wolfgang A.; Jaradat, Hazim; Raisbeck, Bridget M.; Ritter, Mark A. [Univ. of Wisconsin Medical School, Madison, WI (United States). Dept. of Human Oncology

    2006-09-15

    The management of prostate cancer patients with a significant risk of pelvic lymph node involvement is controversial. Both whole pelvis radiotherapy and dose escalation to the prostate have been linked to improved outcome in such patients, but it is unclear whether conventional whole pelvis doses of only 45-50 Gy are optimal for ultimate nodal control. The purpose of this study is to examine the dosimetric and clinical feasibility of combining prostate dose escalation via hypofractionation with conformal avoidance-based IMRT (H-CAD) dose escalation to the pelvic lymph nodes. One conformal avoidance and one conventional plan were generated for each of eight patients. Conformal avoidance-based IMRT plans were generated that specifically excluded bowel, rectum, and bladder. The prostate and lower seminal vesicles (PTV 70) were planned to receive 70 Gy in 2.5 Gy/fraction while the pelvic lymph nodes (PTV 56) were to concurrently receive 56 Gy in 2 Gy/fraction. The volume of small bowel receiving >45 Gy was restricted to 300 ml or less. These conformal avoidance plans were delivered using helical tomotherapy or LINAC-based IMRT with daily imaging localization. All patients received neoadjuvant and concurrent androgen deprivation with a planned total of two years. The conventional, sequential plans created for comparison purposes for all patients consisted of a conventional 4-field pelvic box prescribed to 50.4 Gy (1.8 Gy/fraction) followed by an IMRT boost to the prostate of 25.2 Gy (1.8 Gy/fraction) yielding a final prostate dose of 75.6 Gy. For all plans, the prescription dose was to cover the target structure. Equivalent uniform dose (EUD) analyses were performed on all targets and dose-volume histograms (DVH) were displayed in terms of both physical and normalized total dose (NTD), i.e. dose in 2 Gy fraction equivalents. H-CAD IMRT plans were created for and delivered to all eight patients. Analysis of the H-CAD plans demonstrates prescription dose coverage of >95

  4. Image-guided stereotactic radiotherapy for patients with vestibular schwannoma. A clinical study

    Energy Technology Data Exchange (ETDEWEB)

    Badakhshi, H.; Muellner, S.; Budach, V. [Charite School of Medicine and University Hospital of Berlin, Departments for Radiation Oncology, Berlin (Germany); Wiener, E. [School of Medicine and University Hospital of Berlin, Institute for Neuroradiology, Berlin (Germany)

    2014-06-15

    Local tumor control and functional outcome after linac-based stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) for vestibular schwannoma (VS) were assessed. In all, 250 patients with VS were treated: 190 patients with tumors < 2 cm diameter underwent SRS and 60 patients with tumors >2 to 3.5 cm underwent FSRT. Dose prescription for all cases with SRS (n = 190, 76 %) was 13.5 Gy. For FSRT, mainly two hypofractionated schedules (n = 60, 24 %) with either 7 fractions of 5 Gy (total dose: 35 Gy; n = 35) or 11 fractions of 3.8 Gy (total dose: 41.8 Gy; n = 16) were used. The primary endpoint was local tumor control. Secondary endpoints were symptomatic control and morbidity. The median follow-up was 33.8 months. The 3-year local tumor control was 88.9 %. Local control for SRS and FSRT was 88 and 92 %, respectively. For FSRT with 35 and 41.8 Gy, local control was 90 and 100 %, respectively. There were no acute reactions exceeding grade I. In 61 cases (24.4 % of the entire cohort), trigeminal neuralgia was reported prior to treatment. At last follow-up, 16.3 % (10/61) of those patients reported relief of pain. Regarding facial nerve dysfunction, 45 patients (18 %) presented with symptoms prior to RT. At the last follow-up, 13.3% (6/45) of those patients reported a relief of dysesthesia. Using SRS to treat small VS results in good local control rates. FSRT for larger lesions also seems effective. Severe treatment-related complications are not frequent. Therefore, image-guided stereotactic radiotherapy is an appropriate alternative to microsurgery for patients with VS. (orig.) [German] Wir analysierten die lokale Kontrolle und die funktionellen Verlaeufe bei Patienten mit einem Vestibularisschwannom (VS), die sich einer linacbasierten stereotaktischen Radiochirurgie (SRS) oder einer fraktionierten stereotaktischen Radiotherapie (FSRT) unterzogen. Zwischen 1998 und 2008 wurden 250 Patienten mit einem VS behandelt. In dieser Kohorte wurden 190

  5. Statistical analysis of IMRT dosimetry quality assurance measurements for local delivery guideline

    Directory of Open Access Journals (Sweden)

    Ye Sung-Joon

    2011-03-01

    Full Text Available Abstract Purpose To establish our institutional guideline for IMRT delivery, we statistically evaluated the results of dosimetry quality assurance (DQA measurements and derived local confidence limits using the concept confidence limit of |mean|+1.96σ. Materials and methods From June 2006 to March 2009, 206 patients with head and neck cancer, prostate cancer, liver cancer, or brain tumor were treated using LINAC-based IMRT technique. In order to determine site specific DQA tolerances at a later stage, a hybrid plan with the same fluence maps as in the treatment plan was generated on CT images of a cylindrical phantom of acryl. Points of measurement using a 0.125 cm3 ion-chamber were typically located in the region of high and uniform doses. The planar dose distributions perpendicular to the central axis were measured by using a diode array in solid water with all fields delivered, and assessed using gamma criteria of 3%/3 mm. The mean values and standard deviations were used to develop the local confidence and tolerance limits. The dose differences and gamma pass rates for the different treatment sites were also evaluated in terms of total monitor uints (MU, MU/cGy, and the number of PTV's pieces. Results The mean values and standard deviations of ion-chamber dosimetry differences between calculated and measured doses were -1.6 ± 1.2% for H&N cancer, -0.4 ± 1.2% for prostate and abdominal cancer, and -0.6 ± 1.5% for brain tumor. Most of measured doses (92.2% agreed with the calculated doses within a tolerance limit of ±3% recommended in the literature. However, we found some systematic under-dosage for all treatment sites. The percentage of points passing the gamma criteria, averaged over all treatment sites was 97.3 ± 3.7%. The gamma pass rate and the agreement of ion-chamber dosimetry generally decreased with increasing the number of PTV's pieces, the degree of modulation (MU/cGy, and the total MU beyond 700. Our local confidence limits

  6. Evaluation of volumetric modulated arc therapy for cranial radiosurgery using multiple noncoplanar arcs

    Energy Technology Data Exchange (ETDEWEB)

    Audet, Chantal; Poffenbarger, Brett A.; Chang, Pauling; Jackson, Paul S.; Lundahl, Robert E.; Ryu, Stephen I.; Ray, Gordon R. [Radiation Oncology Department, Palo Alto Medical Foundation, Palo Alto, California 94301 (United States); Neurosurgery Department, Palo Alto Medical Foundation, Palo Alto, California 94301 (United States); Radiation Oncology Department, Palo Alto Medical Foundation, Palo Alto, California 94301 (United States); Neurosurgery Department, Palo Alto Medical Foundation, Palo Alto, California 94301 (United States); Radiation Oncology Department, Palo Alto Medical Foundation, Palo Alto, California 94301 (United States)

    2011-11-15

    Purpose: To evaluate a commercial volumetric modulated arc therapy (VMAT), using multiple noncoplanar arcs, for linac-based cranial radiosurgery, as well as evaluate the combined accuracy of the VMAT dose calculations and delivery. Methods: Twelve patients with cranial lesions of variable size (0.1-29 cc) and two multiple metastases patients were planned (Eclipse RapidArc AAA algorithm, v8.6.15) using VMAT (1-6 noncoplanar arcs), dynamic conformal arc (DCA, {approx}4 arcs), and IMRT (nine static fields). All plans were evaluated according to a conformity index (CI), healthy brain tissue doses and volumes, and the dose to organs at risk. A 2D dose distribution was measured (Varian Novalis Tx, HD120 MLC, 1000 MU/min, 6 MV beam) for the {approx}4 arc VMAT treatment plans using calibrated film dosimetry. Results: The CI (0-1 best) average for all plans was best for {approx}4 noncoplanar arc VMAT at 0.86 compared with {approx}0.78 for IMRT and a single arc VMAT and 0.68 for DCA. The volumes of healthy brain receiving 50% of the prescribed target coverage dose or more (V{sub 50%}) were lowest for the four arc VMAT [RA(4)] and DCA plans. The average ratio of the V{sub 50%} for the other plans to the RA(4) V{sub 50%} were 1.9 for a single noncoplanar arc VMAT [RA(1nc)], 1.4 for single full coplanar arc VMAT [RA(1f)] and 1.3 for IMRT. The V{sub 50%} improved significantly for single isocenter multiple metastases plan when two noncoplanar VMAT arcs were added to a full single coplanar one. The maximum dose to 5 cc of the outer 1 cm rim of healthy brain which one may want to keep below nonconsequential doses of 300-400 cGy, was 2-3 times greater for IMRT, RA(1nc) and RA(1f) plans compared with the multiple noncoplanar arc DCA and RA(4) techniques. Organs at risk near (0-4 mm) to targets were best spared by (i) single noncoplanar arcs when the targets are lateral to the organ at risk and (ii) by skewed nonvertical planes of IMRT fields when the targets are not lateral to the

  7. SU-E-P-41: Imaging Coordination of Cone Beam CT, On-Board Image Conjunction with Optical Image Guidance for SBRT Treatment with Respiratory Motion Management

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y; Campbell, J [INTEGRIS Cancer Institute of Oklahoma, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To spare normal tissue for SBRT lung/liver patients, especially for patients with significant tumor motion, image guided respiratory motion management has been widely implemented in clinical practice. The purpose of this study was to evaluate imaging coordination of cone beam CT, on-board X-ray image conjunction with optical image guidance for SBRT treatment with motion management. Methods: Currently in our clinic a Varian Novlis Tx was utilized for treating SBRT patients implementing CBCT. A BrainLAB X-ray ExacTrac imaging system in conjunction with optical guidance was primarily used for SRS patients. CBCT and X-ray imaging system were independently calibrated with 1.0 mm tolerance. For SBRT lung/liver patients, the magnitude of tumor motion was measured based-on 4DCT and the measurement was analyzed to determine if patients would be beneficial with respiratory motion management. For patients eligible for motion management, an additional CT with breath holding would be scanned and used as primary planning CT and as reference images for Cone beam CT. During the SBRT treatment, a CBCT with pause and continuing technology would be performed with patients holding breath, which may require 3–4 partially scanned CBCT to combine as a whole CBCT depending on how long patients capable of holding breath. After patients being setup by CBCT images, the ExactTrac X-ray imaging system was implemented with patients’ on-board X-ray images compared to breath holding CT-based DRR. Results: For breath holding patients SBRT treatment, after initially localizing patients with CBCT, we then position patients with ExacTrac X-ray and optical imaging system. The observed deviations of real-time optical guided position average at 3.0, 2.5 and 1.5 mm in longitudinal, vertical and lateral respectively based on 35 treatments. Conclusion: The respiratory motion management clinical practice improved our physician confidence level to give tighter tumor margin for sparing normal

  8. Lattice damage assessment and optical waveguide properties in LaAlO3 single crystal irradiated with swift Si ions

    Science.gov (United States)

    Liu, Y.; Crespillo, M. L.; Huang, Q.; Wang, T. J.; Liu, P.; Wang, X. L.

    2017-02-01

    As one of the representative ABO3 perovskite-structured oxides, lanthanum aluminate (LaAlO3) crystal has emerged as one of the most valuable functional-materials, and has attracted plenty of fundamental research and promising applications in recent years. Electronic, magnetic, optical and other properties of LaAlO3 strongly depend on its crystal structure, which could be strongly modified owing to the nuclear or electronic energy loss deposited in an ion irradiation environment and, therefore, significantly affecting the performance of LaAlO3-based devices. In this work, utilizing swift (tens of MeV) Si-ion irradiation, the damage behavior of LaAlO3 crystal induced by nuclear or electronic energy loss has been studied in detail utilizing complementary characterization techniques. Differing from other perovskite-structured crystals in which the electronic energy loss could lead to the formation of an amorphous region based on the thermal spike mechanism, in this case, intense electronic energy loss in LaAlO3 will not induce any obvious structural damage. The effects of ion irradiation on the mechanical properties, including hardness increase and elastic modulus decrease, have been confirmed. On the other hand, considering the potential applications of LaAlO3 in the field of integrated optoelectronics, the optical-waveguide properties of the irradiation region have been studied. The significant correspondence (symmetrical inversion) between the iWKB-reconstructed refractive-index profile and SRIM-simulated dpa profile further proves the effects (irradiation-damage production and refractive-index decrease) of nuclear energy loss during the swift-ion penetration process in LaAlO3 crystal. In the case of the rather-thick damage layer produced by swift-ion irradiation, obtaining a damage profile will be constrained owing to the analysis-depth limitation of the characterization techniques (RBS/channeling), and our analysis process (optical guided-mode measurement and

  9. NIKOS II--a system for noninvasive coronary angiography with synchrotron radiation (abstract)

    Science.gov (United States)

    Dix, W.-R.; Graeff, W.; Heuer, J.; Engelke, K.; Jabs, H.; Kupper, W.; Stellmaschek, K. H.

    1989-07-01

    During the last years attempts have been underway at several synchrotron radiation laboratories1-4 to employ the abrupt change of absorption at the iodine K edge (33.17 keV) to the imaging of coronary arteries. The subtraction of two images taken with photon energies just above and below the edge strongly surpresses background contrast like bone and soft tissue and allows for amplification of iodinated structure contrast. At HASYLAB, for these studies, a beamline at a bending magnet was only available until 1987. At this beamline the system NIKOS I was tested to obtain information on its essential components like monochromator and detector by in-vivo investigations of dogs. The basic feature which differs from the approaches in other laboratoriesis simultaneous registration of two stationary beams in a two-line detector without any beam switching. Based on the experience with this system during the last year all its components have been improved and changed to dimensions capable of taking a 12-cm-wide image of the human heart. At present the new system NIKOS II is under testing at the new wiggler beamline HARWI. The new monochromator comprises two pairs of a thin Si Laue case crystal and a Ge Bragg crystal, each, with inherent focussing of the beam to a horizontal line focus of about 0.5 mm height and 12 cm width. The advantage of the Laue crystals which are optimized in thickness (30 μm) for maximum reflectivity, is the low heat absorption and the full use of the white beam in the production of two monochromatic beams. The crystals are cooled in a stream of helium. Compared to the NIKOS I version5 the detector was changed in the following points: The two detection lines are enlarged to 125 mm width and the phosphor at the entrance is exchangeable to be either made of powderlike Gd2O2S:Tb or of single crystals like CdWO4 or CaF2:Eu separated by thin walls for optimum spatial resolution. The numerical aperture of the glass fiber optics guiding the light via image

  10. 三维可视化图像引导立体定位脑干及松果体区病灶活检术的研究%The technical report of three-dimension visualized image-guided stereotactic biopsy for lesions in pineal region and brain stem

    Institute of Scientific and Technical Information of China (English)

    王亚明; 于新; 李志超; 惠瑞; 刘锐; 尹丰; 张雷鸣; 程岗; 张剑宁

    2015-01-01

    Objective To investigate the methodology,technical essential and significance of threedimension visualized image-guided stereotactic biopsy (SB) for lesions in pineal region and brain stem.Methods A total of 88 cases of lesions in pineal region and brain stem underwent image-guided SB in our department were retrospectively studied.Frame-based and CAS-2 type frameless SBs were performed in 57 and 31 cases respectively.Pre-biopsy three-dimension visualized image reconstruction was performed by SB planning software and the structure related to possible trajectory in each image slice was confirmed.The most suitable trajectory was selected accordingly.For lesions in pineal region,anterior-frontal trans-tentorium cerebella hiatus trajectory for avoiding tentorial margin was used.For lesions in mesencephalon,posteriorfrontal trans-lateral ventrical-thalamus trajectory via the vertical axis of brain stem was used.For pontal lesions,supra-occipital trans-pedunculus cerebellaris medius trajectory was used.Results Histological diagnosis was established in all 88 cases,which gave a high diagnostic yield (100%).Fifty-six lesions (64%) located in brain stem (middle brain and pons) and 32 (36%) in pineal region.In 56 brain stem lesions,there were 38 cases (68%) of glioma,3(5%) lymphoma,2(4%) neurodegenerative disease,6 (11%) multiple sclerosis and tumefactive demyelinating lesion,2 (4%) non-specific inflammation,2 (4%)brain infarct,2(4%) brain metastases,and 1 (2%) radiation necrosis.For lesions in pineal region,there were 18 cases (56%) of germ cell tumor,4(13%) glioma,9 (28%) pineal cell tumor,and 1 (3%) Wemicke encephalopathy.One case (1%) died of biopsy-related hemorrhage.The neurological deficits became severe because of hemorrhage in 5 cases,the medical treatment was adopted in 3 cases (3%)and drainage in 2 (2%).Conclusions Stereotactic biopsy for lesions in pineal region and brain stem was a safe and effective procedure that could help

  11. Integration of optical imaging with a small animal irradiator

    Energy Technology Data Exchange (ETDEWEB)

    Weersink, Robert A., E-mail: robert.weersink@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada and Techna Institute, University Health Network, 124-100 College Street, Toronto, Ontario M5G 1P5 (Canada); Ansell, Steve; Wang, An; Wilson, Graham [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9 (Canada); Shah, Duoaud [Techna Institute, University Health Network, 124-100 College Street, Toronto, Ontario M5G 1P5 (Canada); Lindsay, Patricia E. [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 1A1 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9 (Canada); Techna Institute, University Health Network, 124-100 College Street, Toronto, Ontario M5G 1P5 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 1A1 (Canada); Ontario Cancer Institute, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 1A1 (Canada)

    2014-10-15

    Purpose: The authors describe the integration of optical imaging with a targeted small animal irradiator device, focusing on design, instrumentation, 2D to 3D image registration, 2D targeting, and the accuracy of recovering and mapping the optical signal to a 3D surface generated from the cone-beam computed tomography (CBCT) imaging. The integration of optical imaging will improve targeting of the radiation treatment and offer longitudinal tracking of tumor response of small animal models treated using the system. Methods: The existing image-guided small animal irradiator consists of a variable kilovolt (peak) x-ray tube mounted opposite an aSi flat panel detector, both mounted on a c-arm gantry. The tube is used for both CBCT imaging and targeted irradiation. The optical component employs a CCD camera perpendicular to the x-ray treatment/imaging axis with a computer controlled filter for spectral decomposition. Multiple optical images can be acquired at any angle as the gantry rotates. The optical to CBCT registration, which uses a standard pinhole camera model, was modeled and tested using phantoms with markers visible in both optical and CBCT images. Optically guided 2D targeting in the anterior/posterior direction was tested on an anthropomorphic mouse phantom with embedded light sources. The accuracy of the mapping of optical signal to the CBCT surface was tested using the same mouse phantom. A surface mesh of the phantom was generated based on the CBCT image and optical intensities projected onto the surface. The measured surface intensity was compared to calculated surface for a point source at the actual source position. The point-source position was also optimized to provide the closest match between measured and calculated intensities, and the distance between the optimized and actual source positions was then calculated. This process was repeated for multiple wavelengths and sources. Results: The optical to CBCT registration error was 0.8 mm. Two

  12. Andy Sessler: The Full Life of an Accelerator Physicist

    Science.gov (United States)

    Kim, Kwang-Je; Budnitz, Robert J.; Winick, Herman

    2015-02-01

    This article describes the distinguished career of Andrew M. Sessler, the visionary former director of the Lawrence Berkeley National Laboratory (LBNL), one of the most influential accelerator physicists, and a strong, dedicated human-rights activist. Andy died on 17 April 2014 from cancer at age 85. He grew up in New York City, and attended Harvard (BA in Mathematics, 1949) and then Columbia (PhD in Physics, 1953.) After an NSF postdoc at Cornell with Hans Bethe and a stint on the faculty at the Ohio State University in 1954-59, he joined the Lawrence Radiation Laboratory (now LBNL) in 1959, and spent the remainder of his career there. Although Andy l his mark on several areas of physics, including nuclear structure theory, elementary-particle physics, and many-body problems, his lasting and most important contributions came from his efforts in accelerator physics and engineering, to which he devoted most of his life's work. In collaboration with his colleagues of the legendary Midwestern Universities Research Association, he developed theories for the RF acceleration process and the collective instability phenomena, helping to realize the colliding-beam accelerators with which most of the high-energy-physics discoveries of the last few decades have been made. His work in connection with the free-electron-laser (FEL) amplifier for high-power microwave generation constructed at the Lawrence Livermore National Laboratory anticipated the optical-guiding and the self-amplified spontaneous-emission principles, upon which the success of the X-ray FELs as the fourth-generation light sources is based. Throughout his career Andy made major contributions to issues related to the impact of science and technology on society. He helped usher in a new era of research on energy efficiency and sustainable-energy technology and was instrumental in building the research agendas in those areas for the Atomic Energy Commission (AEC) and later the Department of Energy. With a lifelong

  13. SUPPORT OF GULF OF MEXICO HYDRATE RESEARCH CONSORTIUM: ACTIVITIES TO SUPPORT ESTABLISHMENT OF A SEA FLOOR MONITORING STATION PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Paul Higley; J. Robert Woolsey; Ralph Goodman; Vernon Asper; Boris Mizaikoff; Angela Davis

    2005-11-01

    fiber optic guiding light have been performed and validate the design concept as a potentially viable deep sea sensing probe. (5c) Ray tracing simulations have been performed to evaluate light propagation through HATR elements to facilitate the optimal design of both the sensing probe and optical configuration of ''sphereIR''. (5d) The highly permeable polymer, polydimethylsiloxane (PDMS), was investigated as a potential methane enrichment membrane for IR-ATR sensors. (6) Progress on the Seismo-acoustic Characterization of Sea Floor Properties and Processes at the Hydrate Monitoring Station: (6a) All system components underwent extensive testing in preparation for determining sea floor acoustic reflection responses at the Gas Hydrate Monitoring Station. (6b) Final testing and commissioning have been completed.