WorldWideScience

Sample records for linac-based isocentric electron-photon

  1. Linac-based isocentric electron-photon treatment of radically operated breast carcinoma with enhanced dose uniformity in the field gap area.

    Science.gov (United States)

    Tenhunen, Mikko; Nyman, Heidi; Strengell, Satu; Vaalavirta, Leila

    2009-10-01

    Isocentric treatment technique is a standard method in photon radiotherapy with the primary advantage of requiring only a single patient set-up procedure for multiple fields. However, in electron treatments the size of the standard applicators does not generally allow to use an isocentric treatment technique. In this work we have modified and dosimetrically tested electron applicators for isocentric treatments in combination with photons. An isocentric treatment technique with photons and electrons for postmastectomy radiation therapy (PMRT) has been developed with special emphasis on improving the dose uniformity in the field gap area. Standard electron applicators of two Varian Clinac 2100CD linear accelerators were shortened by 10cm allowing isocentric treatments of 90cmelectron fields. Shortened applicators were commissioned and configured for the electron calculation algorithm of the treatment planning system. The field arrangement of PMRT was modified by combining three photon field segments with different gaps and overlaps with the electron field to improve dose uniformity. The developed technique and two other methods for PMRT were compared with each other in the group of 20 patients. Depth dose characteristics of the shortened applicators remained unchanged from those of the standard applicators. Penumbrae were broadened by 0-3mm depending on electron energy and depth as the air gap was increased from 5cm (standard applicator at SSD=100cm) to 10cm (shortened applicator at SSD=95cm). The dose calculation performance of the modified applicators at 95cmelectron dose calculation algorithm of the treatment planning system (Varian Eclipse). The modified isocentric treatment technique for PMRT was superior than the traditional two-dimensional technique. However, with the tangential photon fields without electrons the even better dose uniformity within PTV could be achieved but with increased irradiation of healthy tissues (lung, heart, and contralateral breast

  2. Linac based radiosurgery and stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Mackie, T.R.

    2008-01-01

    The following topics were discussed: Definition of stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT); Stereo market; Indications for SRS/SRT; History of linac-based SRS/SRT; Variety of systems; QA for SRS; Localization; and Imaging. (P.A.)

  3. Isocentric integration of intensity-modulated radiotherapy with electron fields improves field junction dose uniformity in postmastectomy radiotherapy.

    Science.gov (United States)

    Wright, Pauliina; Suilamo, Sami; Lindholm, Paula; Kulmala, Jarmo

    2014-08-01

    In postmastectomy radiotherapy (PMRT), the dose coverage of the planning target volume (PTV) with additional margins, including the chest wall, supraclavicular, interpectoral, internal mammary and axillar level I-III lymph nodes, is often compromised. Electron fields may improve the medial dose coverage while maintaining organ at risk (OAR) doses at an acceptable level, but at the cost of hot and cold spots at the electron and photon field junction. To improve PMRT dose coverage and uniformity, an isocentric technique combining tangential intensity-modulated (IM)RT fields with one medial electron field was implemented. For 10 postmastectomy patients isocentric IMRT with electron plans were created and compared with a standard electron/photon mix and a standard tangent technique. PTV dose uniformity was evaluated based on the tolerance range (TR), i.e. the ratio of the standard deviation to the mean dose, a dice similarity coefficient (DSC) and the 90% isodose coverage and the hot spot volumes. OAR and contralateral breast doses were also recorded. IMRT with electrons significantly improved the PTV dose homogeneity and conformity based on the TR and DSC values when compared with the standard electron/photon and tangent technique (p < 0.02). The 90% isodose coverage improved to 86% compared with 82% and 80% for the standard techniques (p < 0.02). Compared with the standard electron/photon mix, IMRT smoothed the dose gradient in the electron and photon field junction and the volumes receiving a dose of 110% or more were reduced by a third. For all three strategies, the OAR and contralateral breast doses were within clinically tolerable limits. Based on these results two-field IMRT combined with an electron field is a suitable strategy for PMRT.

  4. Monte Carlo electron/photon transport

    International Nuclear Information System (INIS)

    Mack, J.M.; Morel, J.E.; Hughes, H.G.

    1985-01-01

    A review of nonplasma coupled electron/photon transport using Monte Carlo method is presented. Remarks are mainly restricted to linerarized formalisms at electron energies from 1 keV to 1000 MeV. Applications involving pulse-height estimation, transport in external magnetic fields, and optical Cerenkov production are discussed to underscore the importance of this branch of computational physics. Advances in electron multigroup cross-section generation is reported, and its impact on future code development assessed. Progress toward the transformation of MCNP into a generalized neutral/charged-particle Monte Carlo code is described. 48 refs

  5. Coupled electron-photon radiation transport

    International Nuclear Information System (INIS)

    Lorence, L.; Kensek, R.P.; Valdez, G.D.; Drumm, C.R.; Fan, W.C.; Powell, J.L.

    2000-01-01

    Massively-parallel computers allow detailed 3D radiation transport simulations to be performed to analyze the response of complex systems to radiation. This has been recently been demonstrated with the coupled electron-photon Monte Carlo code, ITS. To enable such calculations, the combinatorial geometry capability of ITS was improved. For greater geometrical flexibility, a version of ITS is under development that can track particles in CAD geometries. Deterministic radiation transport codes that utilize an unstructured spatial mesh are also being devised. For electron transport, the authors are investigating second-order forms of the transport equations which, when discretized, yield symmetric positive definite matrices. A novel parallelization strategy, simultaneously solving for spatial and angular unknowns, has been applied to the even- and odd-parity forms of the transport equation on a 2D unstructured spatial mesh. Another second-order form, the self-adjoint angular flux transport equation, also shows promise for electron transport

  6. Setup uncertainties: consequences for multi-isocentre stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Ebert, M.A.; Harper, C.S.

    2000-01-01

    Full text: Beam data for use in dose calculations by planning systems is generally measured under static and controlled conditions. Yet, patient motion and setup uncertainties will effectively blur the resulting dose distributions leading to a discrepancy between planned and delivered dose distributions. This is particularly so for stereotactic radiotherapy where small well-defined fields are used. When multiple isocentres are used (possibly for larger irregular lesions), relative motion of isocentres due to setup variations may have deleterious effects on the intended radiation delivery. The influence of setup uncertainties was examined by performing a three-dimensional convolution of measured off-axis ratio (OAR) data with a Maxwellian distribution, with standard deviations representing several feasible levels of inaccuracy in patient setup. A sample of patient plans (predominantly multi-isocentre plans) were then considered using original (measured) OAR data, and then modified data in order to observe the resulting effect. The effect of systematic localisation error was also considered by examining resulting DVHs as isocentres were shifted by fixed amounts. In all cases considered, the maximum dose varied quite minimally with increase in setup error with the variation decreasing with increasing high-dose volume. The minimum dose however varied more significantly, and this has serious consequences for dose prescription as the minimum dose can be the controlling factor in treatment efficacy. For multi-isocentre plans, the degree of non-uniformity generated by setup error was not as significant as originally expected. This is in part due to the non-uniformity already present in such plans to begin with. Through incorporation of the effect of setup error into planning data, the influence of setup variations on dose distributions for multi-isocentre treatments has been determined. This influence should be considered when creating plans based on the level of spatial

  7. The width of electron-photon cascades in air

    International Nuclear Information System (INIS)

    Allan, H.R.; Crannell, C.J.; Hough, J.H.; Shutie, P.F.; Sun, M.P.

    1975-01-01

    A new Monte-Carlo simulation of electron-photon cascade development is shown to give results in agreement with a) the calculations of Nordheim et al, b) simulations using the Berger-Seltzer electron photon transport programme and c) experimental measurements in water. However, the lateral spread is much narrower than that given by the Nishimura-Kamata functions or the Messel-Crawford tabulations. (orig.) [de

  8. A linac-based stereotactic irradiation technique of uveal melanoma

    International Nuclear Information System (INIS)

    Dieckmann, Karin; Bogner, Joachim; Georg, Dietmar; Zehetmayer, Martin; Kren, Gerhard; Poetter, Richard

    2001-01-01

    Purpose: To describe a stereotactic irradiation technique for uveal melanomas performed at a linac, based on a non-invasive eye fixation and eye monitoring system. Methods: For eye immobilization a light source system is integrated in a standard stereotactic mask system in front of the healthy eye: During treatment preparation (computed tomography/magnetic resonance imaging) as well as for treatment delivery, patients are instructed to gaze at the fixation light source. A mini-video camera monitors the pupil center position of the diseased eye. For treatment planning and beam delivery standard stereotactic radiotherapy equipment is used. If the pupil center deviation from a predefined 'zero-position' exceeds 1 mm (for more than 2 s), treatment delivery is interrupted. Between 1996 and 1999 60 patients with uveal melanomas, where (i) tumor height exceeded 7 mm, or (ii) tumor height was more than 3 mm, and the central tumor distance to the optic disc and/or the macula was less than 3 mm, have been treated. A total dose of 60 or 70 Gy has been given in 5 fractions within 10 days. Results: The repositioning accuracy in the mask system is 0.47±0.36 mm in rostral-occipital direction, 0.75±0.52 mm laterally, and 1.12±0.96 mm in vertical direction. An eye movement analysis performed for 23 patients shows a pupil center deviation from the 'zero' position<1 mm in 91% of all cases investigated. In a theoretical analysis, pupil center deviations are correlated with GTV 'movements'. For a pupil center deviation of 1 mm (rotation of the globe of 5 degree sign ) the GTV is still encompassed by the 80% isodose in 94%. Conclusion: For treatments of uveal melanomas, linac-based stereotactic radiotherapy combined with a non-invasive eye immobilization and monitoring system represents a feasible, accurate and reproducible method. Besides considerable technical requirements, the complexity of the treatment technique demands an interdisciplinary team continuously dedicated to this

  9. Poster — Thur Eve — 65: A dosimetric comparison of isocentric and non-isocentric coplanar SBRT VMAT plans for peripheral lung tumours

    International Nuclear Information System (INIS)

    Conroy, L; Liu, HW; Lau, H; Smith, WL

    2014-01-01

    Volumetric modulated arc therapy (VMAT) delivers lung sterotactic body radiotherapy (SBRT) in shorter treatment time and less monitor units with comparable coverage and organ at risk sparing compared to conventional SBRT treatments. Isocentric VMAT treatment of peripheral lung tumours occasionally requires couch shifts that can inhibit 360° gantry rotation, resulting in additional imaging shifts for each treatment session, and increased potential for involuntary in-fraction motion. Here, we investigate whether non-isocentric VMAT plans can achieve comparable plan quality to isocentric plans for peripheral lung tumours. Three patient plans were selected with targets displaced > 8.5 cm (range: 8.8 – 9.9 cm) laterally from patient midline. For each patient, a plan with isocentre placed within the target volume (isocentric plan) was created and optimized. The same optimization parameters were then used to create a plan with the isocentre at patient midline (non-isocentric plan). Plan quality was evaluated and compared based on planning target volume (PTV) coverage, high dose spillage, dose homogeneity, intermediate dose spillage, dose fall-off gradient, and organ at risk contraints. Non-isocentric plans of equivalent plan quality to isocentric plans were achieved for all patients by optimizing collimator rotations. Field isocentres can be placed at patient midline, as opposed to inside the target volume, with no significant degradation in VMAT plan quality for lateral tumour displacements up to 10 cm. Non-isocentric treatment of peripheral lung tumours could result in decreased overall treatment session time and eliminate the need for imaging shifts prior to VMAT treatment

  10. Linac based photofission inspection system employing novel detection concepts

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, John, E-mail: jstevenson@rapiscansystems.com [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Gozani, Tsahi, E-mail: tgozani@rapiscansystems.com [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States); Elsalim, Mashal; Condron, Cathie; Brown, Craig [Rapiscan Laboratories, Inc., 520 Almanor Avenue, Sunnyvale, CA 94085 (United States)

    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{sub 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{sup 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

  11. Linac based photofission inspection system employing novel detection concepts

    International Nuclear Information System (INIS)

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

    2011-01-01

    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

  12. Electron/Photon Verification Calculations Using MCNP4B

    Energy Technology Data Exchange (ETDEWEB)

    D. P. Gierga; K. J. Adams

    1999-04-01

    MCNP4BW was released in February 1997 with significant enhancements to electron/photon transport methods. These enhancements have been verified against a wide range of published electron/photon experiments, spanning high energy bremsstrahlung production to electron transmission and reflection. The impact of several MCNP tally options and physics parameters was explored in detail. The agreement between experiment and simulation was usually within two standard deviations of the experimental and calculational errors. Furthermore, sub-step artifacts for bremsstrahlung production were shown to be mitigated. A detailed suite of electron depth dose calculations in water is also presented. Areas for future code development have also been explored and include the dependence of cell and detector tallies on different bremsstrahlung angular models and alternative variance reduction splitting schemes for bremsstrahlung production.

  13. Inelastic electron photon scattering at moderate four momentum transfers

    International Nuclear Information System (INIS)

    Berger, C.; Genzel, H.; Grigull, R.; Lackas, W.; Raupach, F.; Klovning, A.; Lillestoel, E.; Skard, J.A.; Ackermann, H.; Buerger, J.

    1980-10-01

    We present new high statistics data on hadron production in photon photon reactions. The data are analyzed in terms of an electron photon scattering formalism. The dependence of the total cross section on Q 2 , the four momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector Dominance and the quark model. (orig.)

  14. 7-MeV electron LINAC based pulse radiolysis facility at RPCD, BARC

    International Nuclear Information System (INIS)

    Naik, C.B.; Nadkarni, S.A.; Toley, M.A.; Shinde, S.J.; Naik, P.D.

    2017-01-01

    7-MeV electron LINAC based pulse radiolysis facility is operational in Chemistry Group of BARC since 1986. The Accelerator is housed in B-132 room in basement of Modular Labs. BARC Accelerator was procured from Radiation Dynamics Inc. UK and its detection system was indigenously developed

  15. High-brightness electron guns for linac-based light sources

    International Nuclear Information System (INIS)

    Lewellen, J.W.

    2004-01-01

    Most proposed linac-based light sources, such as single-pass free-electron lasers and energy-recovery-linacs, require very high-brightness electron beams in order to achieve their design performance. These beam requirements must be achieved not on an occasional basis, but rather must be met by every bunch produced by the source over extended periods of time. It is widely assumed that the beam source will be a photocathode electron gun; the selection of accelerator technique (e.g., dc or rf) for the gun is more dependent on the application.The current state of the art of electron beam production is adequate but not ideal for the first generation of linac-based light sources, such as the Linac Coherent Light Source (LCLS) x-ray free-electron laser (X-FEL). For the next generation of linac-based light sources, an order of magnitude reduction in the transverse electron beam emittance is required to significantly reduce the cost of the facility. This is beyond the present state of the art, given the other beam properties that must be maintained. The requirements for current and future linac-based light source beam sources are presented here, along with a review of the present state of the art. A discussion of potential paths towards meeting future needs is presented at the conclusion.

  16. 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

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

    NARCIS (Netherlands)

    Goloviznin, V.V.; Oepts, W.; Wiel, van der 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

  18. An Electron/Photon/Relaxation Data Library for MCNP6

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, III, H. Grady [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-07

    The capabilities of the MCNP6 Monte Carlo code in simulation of electron transport, photon transport, and atomic relaxation have recently been significantly expanded. The enhancements include not only the extension of existing data and methods to lower energies, but also the introduction of new categories of data and methods. Support of these new capabilities has required major additions to and redesign of the associated data tables. In this paper we present the first complete documentation of the contents and format of the new electron-photon-relaxation data library now available with the initial production release of MCNP6.

  19. Multidimensional electron-photon transport with standard discrete ordinates codes

    International Nuclear Information System (INIS)

    Drumm, C.R.

    1995-01-01

    A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages of using an established discrete ordinates solver, e.g. immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and man-made radiation environments. The cross sections have been successfully used in the DORT, TWODANT and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electronphoton transport problems

  20. Energy spectra from coupled electron-photon slowing down

    International Nuclear Information System (INIS)

    Beck, H.L.

    1976-08-01

    A coupled electron-photon slowing down calculation for determining electron and photon track length in uniform homogeneous media is described. The method also provides fluxes for uniformly distributed isotropic sources. Source energies ranging from 10 keV to over 10 GeV are allowed and all major interactions are treated. The calculational technique and related cross sections are described in detail and sample calculations are discussed. A listing of the Fortran IV computer code used for the calculations is also included. 4 tables, 7 figures, 16 references

  1. Study of Compton broadening due to electron-photon scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao M.

    2010-01-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radia­tion field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation. The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons. It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle. We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  2. Study of Compton Broadening Due to Electron-Photon Scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao, M.

    2010-06-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  3. Light flavon signals at electron-photon colliders

    Science.gov (United States)

    Muramatsu, Yu; Nomura, Takaaki; Shimizu, Yusuke; Yokoya, Hiroshi

    2018-01-01

    Flavor symmetries are useful to realize fermion flavor structures in the standard model (SM). In particular, the discrete A4 symmetry is used to realize lepton flavor structures, and some scalars—called flavons—are introduced to break this symmetry. In many models, flavons are assumed to be much heavier than the electroweak scale. However, our previous work showed that a flavon mass around 100 GeV is allowed by experimental constraints in the A4 symmetric model with a residual Z3 symmetry. In this paper, we discuss collider searches for such a light flavon φT. We find that electron-photon collisions at the International Linear Collider have advantages for searching for these signals. In electron-photon collisions, flavons are produced as e-γ →l-φT and decay into two charged leptons. Then, we analyze signals of the flavor-conserving final state τ+τ-e- and the flavor-violating final states τ+μ-μ- and μ+τ-τ- by carrying out numerical simulations. For the former final state, SM background can be strongly suppressed by imposing cuts on the invariant masses of final-state leptons. For the latter final states, SM background is extremely small, because in the SM there are no such flavor-violating final states. We then find that sufficient discovery significance can be obtained, even if flavons are heavier than the lower limits from flavor physics.

  4. Multidimensional electron-photon transport with standard discrete ordinates codes

    International Nuclear Information System (INIS)

    Drumm, C.R.

    1997-01-01

    A method is described for generating electron cross sections that are comparable with standard discrete ordinates codes without modification. There are many advantages of using an established discrete ordinates solver, e.g. immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and man-made radiation environments. The cross sections have been successfully used in the DORT, TWODANT and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electron-photon transport problems. The key to the method is a simultaneous solution of the continuous-slowing-down (CSD) portion and elastic-scattering portion of the scattering source by the Goudsmit-Saunderson theory. The resulting multigroup-Legendre cross sections are much smaller than the true scattering cross sections that they represent. Under certain conditions, the cross sections are guaranteed positive and converge with a low-order Legendre expansion

  5. Multidimensional electron-photon transport with standard discrete ordinates codes

    International Nuclear Information System (INIS)

    Drumm, C.R.

    1997-01-01

    A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages to using an established discrete ordinates solver, e.g., immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and synthetic radiation environments. The cross sections have been successfully used in the DORT, TWODANT, and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electron-photon transport problems. The key to the method is a simultaneous solution of the continuous-slowing-down and elastic-scattering portions of the scattering source by the Goudsmit-Saunderson theory. The resulting multigroup-Legendre cross sections are much smaller than the true scattering cross sections that they represent. Under certain conditions, the cross sections are guaranteed positive and converge with a low-order Legendre expansion

  6. Digital tomosynthesis using a 35 mm X-ray cinematogram during an isocentric rotational motion

    International Nuclear Information System (INIS)

    Maeda, Hirofumi; Aikawa, Hisayuki; Maeda, Tohru; Miyake, Hidetoshi; Sugahara, Tetsuo.

    1988-01-01

    Digital tomosynthesis is performed using a 35 mm X-ray cinematogram obtained during an isocentric rotational motion of the cineangiographic apparatus. Formula of image shift for digital tomosynthesis using an isocentric rotational motion is induced by perspective projection and affine transformation. Images of desired layer are aligned at the same point in the image processor and summed. Resultant final image is displayed in sharp focus. We can set tomosynthetic factors on any desired projection, sweep angle and depth as concerns digital tomosynthesis using an isocentric rotational motion. Especially we emphasize that tomosynthesis tilted for central axis of isocentric rotational motion can be obtained, using shear transformation of image in the image processor. (author)

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

    International Nuclear Information System (INIS)

    Minehara, E.J.; Yamauchi, T.; Sugimoto, M.

    2000-01-01

    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)

  8. Present status and future directions of the JAERI superconducting RF linac-based FEL

    International Nuclear Information System (INIS)

    Minehara, EJ.; Yamauchi, T.; Sugimori, M.; Sawamura, M.; Hajima, R.; Nagai, R.; Kikuzawa, N.; Nishimori, N.; Shizuma, T.

    2000-01-01

    The JAERI superconducting rf linac based FEL has successfully been lased to produce a 2.34kW FEL light and l00kW electron beam output in quasi continuous wave operation in February 2000. Twice larger output than the present program goal of 1kW was 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 2 years program goal is the 100kW class FEL light and a few 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 and engineering design options needed for such a very high power operation will be discussed to improve and to upgrade the existing facility. Finally, several applications, table-top superconducting rf linac based FELs, and an X-ray FEL R and D will be discussed as a next-five years program at JAERI-FEL laboratory. (author)

  9. Coupled electron/photon transport in static external magnetic fields

    International Nuclear Information System (INIS)

    Halbleib, J.A. Sr.; Vandevender, W.H.

    A model is presented which describes coupled electron/photon transport in the presence of static magnetic fields of arbitrary spatial dependence. The method combines state-of-the-art condensed-history electron collisional Monte Carlo and single-scattering photon Monte Carlo, including electron energy-loss straggling and the production and transport of all generations of secondaries, with numerical field integration via the best available variable-step-size Runge-Kutta-Fehlberg or variable-order/variable-step-size Adams PECE differential equation solvers. A three-dimensional cartesian system is employed in the description of particle trajectories. Although the present model is limited to multilayer material configurations, extension to more complex material geometries should not be difficult. Among the more important options are (1) a feature which permits the neglect of field effects in regions where transport is collision dominated and (2) a method for describing the transport in variable-density media where electron energies and material densities are sufficiently low that the density effect on electronic stopping powers may be neglected. (U.S.)

  10. EGS4, Electron Photon Shower Simulation by Monte-Carlo

    International Nuclear Information System (INIS)

    1998-01-01

    1 - Description of program or function: The EGS code system is one of a chain of three codes designed to solve the electromagnetic shower problem by Monte Carlo simulation. This chain makes possible simulation of almost any electron-photon transport problem conceivable. The structure of the system, with its global features, modular form, and structured programming, is readily adaptable to virtually any interfacing scheme that is desired on the part of the user. EGS4 is a package of subroutines plus block data with a flexible user interface. This allows for greater flexibility without requiring the user to be overly familiar with the internal details of the code. Combining this with the macro facility capabilities of the Mortran3 language, this reduces the likelihood that user edits will introduce bugs into the code. EGS4 uses material cross section and branching ratio data created and fit by the companion code, PEGS4. EGS4 allows for the implementation of importance sampling and other variance reduction techniques such as leading particle biasing, splitting, path length biasing, Russian roulette, etc. 2 - Method of solution: EGS employs the Monte Carlo method of solution. It allows all of the fundamental processes to be included and arbitrary geometries can be treated, also. Other minor processes, such as photoneutron production, can be added as a further generalization. Since showers develop randomly according to the quantum laws of probability, each shower is different. We again are led to the Monte Carlo method. 3 - Restrictions on the complexity of the problem: None noted

  11. [Technique of complex mammary irradiation: Mono-isocentric 3D conformational radiotherapy and helical tomotherapy].

    Science.gov (United States)

    Vandendorpe, B; Guilbert, P; Champagne, C; Antoni, T; Nguyen, T D; Gaillot-Petit, N; Servagi Vernat, S

    2017-12-01

    To evaluate the dosimetric contribution of helical tomotherapy for breast cancers compared with conformal radiotherapy in mono-isocentric technique. For 23 patients, the dosimetric results in mono-isocentric 3D conformational radiotherapy did not satisfy the constraints either of target volumes nor organs at risk. A prospective dosimetric comparison between mono-isocentric 3D conformational radiotherapy and helical tomotherapy was therefore carried out. The use of helical tomotherapy showed a benefit in these 23 patients, with either an improvement in the conformity index or homogeneity, but with an increase in low doses. Of the 23 patients, two had pectus excavatum, five had past thoracic irradiation and two required bilateral irradiation. The other 14 patients had a combination of morphology and/or indication of lymph node irradiation. For these patients, helical tomotherapy was therefore preferred to mono-isocentric 3D conformational radiotherapy. Tomotherapy appears to provide better homogeneity and tumour coverage. This technique of irradiation may be justified in the case of morphological situations such as pectus exavatum and in complex clinical situations. In other cases, conformal radiotherapy in mono-isocentric technique remains to be favoured. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  12. Induction-linac based free-electron laser amplifiers for plasma heating

    International Nuclear Information System (INIS)

    Jong, R.A.

    1988-01-01

    We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging form 280 to 560 GHz. 7 refs., 1 tab

  13. On isocentre adjustment and quality control in linear accelerator based radiosurgery with circular collimators and room lasers

    Energy Technology Data Exchange (ETDEWEB)

    Treuer, H. [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany). E-mail: h.treuer at uni-koeln.de; Hoevels, M.; Luyken, K.; Gierich, A.; Sturm, V. [Department of Stereotaxy and Functional Neurosurgery, University of Cologne, Cologne (Germany); Kocher, M.; Mueller, R.-P. [Department of Radiotherapy, University of Cologne, Cologne (Germany)

    2000-08-01

    We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the wobble of the gantry and table rotation movement, the effect of gantry sag, the stereotactic collimator alignment, and the minimal distance between gantry and table rotation axes. Since the method is based on densitometric measurements, beam spot stability is implicitly tested. The method developed is also suitable for quality assurance and has proved to be useful in optimizing isocentric accuracy. The method is simple to perform and only requires a film box and film scanner for instrumentation. Thus, the method has the potential to become widely available and may therefore be useful in standardizing the description of linear accelerator based radiosurgical systems. (author)

  14. On isocentre adjustment and quality control in linear accelerator based radiosurgery with circular collimators and room lasers

    International Nuclear Information System (INIS)

    Treuer, H.; Kocher, M.; Mueller, R.-P.

    2000-01-01

    We have developed a densitometric method for measuring the isocentric accuracy and the accuracy of marking the isocentre position for linear accelerator based radiosurgery with circular collimators and room lasers. Isocentric shots are used to determine the accuracy of marking the isocentre position with room lasers and star shots are used to determine the wobble of the gantry and table rotation movement, the effect of gantry sag, the stereotactic collimator alignment, and the minimal distance between gantry and table rotation axes. Since the method is based on densitometric measurements, beam spot stability is implicitly tested. The method developed is also suitable for quality assurance and has proved to be useful in optimizing isocentric accuracy. The method is simple to perform and only requires a film box and film scanner for instrumentation. Thus, the method has the potential to become widely available and may therefore be useful in standardizing the description of linear accelerator based radiosurgical systems. (author)

  15. New Techniques for Optimal Treatment Planning for LINAC-based Sterotactic Radiosurgery

    International Nuclear Information System (INIS)

    Suh, Tae Suk

    1992-01-01

    Since LINAC-based stereotactic radiosurgery uses multiple noncoplanar arcs, three-dimensional dose evaluation and many beam parameters, a lengthy computation time is required to optimize even the simplest case by a trial and error. The basic approach presented in this paper is to show promising methods using an experimental optimization and an analytic optimization. The purpose of this paper is not to describe the detailed methods, but introduce briefly, proceeding research done currently or in near future. A more detailed description will be shown in ongoing published papers. Experimental optimization is based on two approaches. One is shaping the target volumes through the use of multiple isocenters determined from dose experience and testing. The other method is conformal therapy using a beam eye view technique and field shaping. The analytic approach is to adapt computer-aided design optimization in finding optimum irradiation parameters automatically

  16. A photocathode rf gun design for a mm-wave linac-based FEL

    Energy Technology Data Exchange (ETDEWEB)

    Nassiri, A.; Berenc, T,; Foster, J.; Waldschmidt, G.; Zhou, J.

    1995-07-01

    In recent years, advances in the rf gun technology have made it possible to produce small beam emittances suitable for short period microundulators which take advantage of the low emittance beam to reduce the wavelength of FELs. At the Advanced Photon Source, we are studying the design of a compact 50-MeV superconducting mm-wave linac-based FEL for the production of short wavelengths ({approximately}300 nm) to carry out FEL demonstration experiments. The electron source considered for the linac is a 30- GHz, 3 1/2-cell {pi}-mode photocathode rf gun. For cold model rf measurements a 15-GHz prototype structure was fabricated. Here we report on the design, numerical modelling and the initial cold-model rf measurement results on the 15-GHz prototype structure.

  17. TH-C-BRC-03: Emerging Linac Based SRS/SBRT Technologies with Modulated Arc Delivery

    International Nuclear Information System (INIS)

    Ren, L.

    2016-01-01

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  18. A photocathode rf gun design for a mm-wave linac-based FEL

    International Nuclear Information System (INIS)

    Nassiri, A.; Berenc, T.; Foster, J.; Waldschmidt, G.; Zhou, J.

    1995-01-01

    In recent years, advances in the rf gun technology have made it possible to produce small beam emittances suitable for short period microundulators which take advantage of the low emittance beam to reduce the wavelength of FELs. At the Advanced Photon Source, we are studying the design of a compact 50-MeV superconducting mm-wave linac-based FEL for the production of short wavelengths (∼300 nm) to carry out FEL demonstration experiments. The electron source considered for the linac is a 30- GHz, 3 1/2-cell π-mode photocathode rf gun. For cold model rf measurements a 15-GHz prototype structure was fabricated. Here we report on the design, numerical modelling and the initial cold-model rf measurement results on the 15-GHz prototype structure

  19. TH-C-BRC-03: Emerging Linac Based SRS/SBRT Technologies with Modulated Arc Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Ren, L. [Duke University Medical Center (United States)

    2016-06-15

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  20. Single-fraction vs. fractionated linac-based stereotactic radiosurgery for vestibular schwannoma: a single-institution study

    NARCIS (Netherlands)

    Meijer, O. W. M.; Vandertop, W. P.; Baayen, J. C.; Slotman, B. J.

    2003-01-01

    PURPOSE: In this single-institution trial, we investigated whether fractionated stereotactic radiation therapy is superior to single-fraction linac-based radiosurgery with respect to treatment-related toxicity and local control in patients with vestibular schwannoma. METHODS AND MATERIALS: All 129

  1. A quality assurance device for the accuracy of the isocentres of teletherapy and simulation machines

    International Nuclear Information System (INIS)

    Arjomandy, Bijan; Altschuler, Martin D.

    2000-01-01

    A new quality assurance device has been designed to measure the location and wobble of the radiation isocentre of linacs and simulation machines as a function of gantry rotation. The radiation isocentre is the intersection in space of the central x-rays of a linac or simulation machine at different gantry angles. Six radio-opaque markers 1 mm in size are embedded in a radio-transparent calibration object (specifically, a hollowed cube) in such a way that the markers are non-coplanar and uniquely identifiable in radiographic projections. The projective radiographs are obtained on the films held by the film holder attached to the gantry during the QA procedure. The marker positions of the calibration object define a known 3D reference frame, and their image positions on each radiograph determine the projective (3D to 2D matrix) transformation for that radiograph. Once the transformation is found, a 3D ray from the radiation source to any radiograph pixel becomes known. The radiographic pixels are coordinated (positioned and scaled) with respect to the projected image of radio-opaque fiducial cross-hairs fixed to a block tray and thus to the gantry. We select the central ray to correspond to the radiographic pixel whose rays at different gantry angles intersect in the smallest spatial domain. That pixel is found by a spiral search in the radiograph outward from the image of the radio-opaque cross-hair intersection. The wobble of the isocentre is defined by the set of points (on the central rays) at closest approach to the isocentre. The device was tested and compared with commercially available QA devices. It is able to locate the isocentre to within 0.5 mm. The offset of this derived radiation isocentre from the intersection of the positioning lasers can be found. To do this, the calibration object is initially placed so that the laser intersection point falls on a seventh radio-opaque marker near the centre of the hollow cube calibration object. The seventh marker

  2. LINAC based stereotactic radiotherapy of uveal melanoma: 4 years clinical experience

    International Nuclear Information System (INIS)

    Dieckmann, Karin; Georg, Dietmar; Zehetmayer, Martin; Bogner, Joachim; Georgopoulos, Michael; Poetter, Richard

    2003-01-01

    Purpose: To study local tumor control and radiogenic side effects after fractionated LINAC based stereotactic radiotherapy for selected uveal melanoma. Patients and methods: Between June 1997 and March 2001, 90 patients suffering from uveal melanoma were treated at a LINAC with 6 MV. The head was immobilized with a modified stereotactic frame system (BrainLAB). For stabilization of the eye position a light source was integrated into the mask system in front of the healthy or the diseased eye. A mini-video camera was used for on-line eye movement control. Tumors included in the study were either located unfavorably with respect to macula and optical disc ( 7 mm. Median tumor volume was 305±234 mm 3 (range 70-1430 mm 3 ), and mean tumor height was 5.4±2.3 mm (range 2.7-15.9 mm). Total doses of 70 (single dose 14 Gy at 80% isodose) or 60 Gy (single dose 12 Gy at 80% isodose) were applied in five fractions within 10 days. The first fractionation results in total dose (TD) (2 Gy) of 175 Gy for tumor and 238 Gy for normal tissue, corresponding values for the second fractionation schedule are 135 and 180 Gy, respectively. Results: After a median follow-up of 20 months (range 1-48 months) local control was achieved in 98% (n=88). The mean relative tumor reductions were 24, 27, and 37% after 12, 24 and 36 months. Three patients (3.3%) developed metastases. Secondary enucleation was performed in seven patients (7.7%). Long term side effects were retinopathy (25.5%), cataract (18.9%), optic neuropathy (20%), and secondary neovascular glaucoma (8.8%). Conclusion: Fractionated LINAC based stereotactic photon beam therapy in conjunction with a dedicated eye movement control system is a highly effective method to treat unfavorably located uveal melanoma. Total doses of 60 Gy (single dose 12 Gy) are considered to be sufficient to achieve good local tumor control

  3. Dosimetry of Gamma Knife and linac-based radiosurgery using radiochromic and diode detectors

    International Nuclear Information System (INIS)

    Somigliana, A.; Borelli, S.; Zonca, G.; Pignoli, E.; Loi, G.; Marchesini, R.; Cattaneo, G.M.; Fiorino, C.; Vecchio, A. del; Calandrino, R.

    1999-01-01

    In stereotactic radiosurgery the choice of appropriate detectors, whether for absolute or relative dosimetry, is very important due to the steep dose gradient and the incomplete lateral electronic equilibrium. For both linac-based and Leksell Gamma Knife radiosurgery units, we tested the use of calibrated radiochromic film to measure absolute doses and relative dose distributions. In addition a small diode was used to estimate the relative output factors. The data obtained using radiochromic and diode detectors were compared with measurements performed with other conventional methods of dosimetry, with calculated values by treatment planning systems and with data prestored in the treatment planning system supplied by the Leksell Gamma Knife (LGK) vendor. Two stereotactic radiosurgery techniques were considered: Leksell Gamma Knife (using γ-rays from 60 Co) and linac-based radiosurgery (LR) (6 MV x-rays). Different detectors were used for both relative and absolute dosimetry: relative output factors (OFs) were estimated by using radiochromic and radiographic films and a small diode; relative dose distributions in the axial and coronal planes of a spherical polystyrene phantom were measured using radiochromic film and calculated by two different treatment planning systems (TPSs). The absolute dose at the sphere centre was measured by radiochromic film and a small ionization chamber. An accurate selection of radiochromic film was made: samples of unexposed film showing a percentage standard deviation of less than 3% were used for relative dose profiles, and for absolute dose and OF evaluations this value was reduced to 1.5%. Moreover a proper calibration curve was made for each set of measurements. With regard to absolute doses, the results obtained with the ionization chamber are in good correlation with radiochromic film-generated data, for both LGK and LR, showing a dose difference of less than 1%. The output factor evaluations, performed using different methods

  4. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Zimmermann, S. J.; Rowshanfarzad, P.; Ebert, M. A.

    2015-01-01

    ) and the radiation field centre (RFC) is calculated. A software package was developed for accurate calculation of the linac isocentre position. This requires precise determination of the position of the ball bearing and the RFC. Results: Data were acquired for 6 MV, 18 MV and flattening filter free (FFF) 6 MV FFF...... radiation isocentre prior to routine use of the cone-beam CT system. The isocentre determination method used in the XVI software is not available to users. The aim of this work is to perform an independent evaluation of the Elekta XVI 4.5 software for isocentre verification with focus on the robustness...... iView GT software. Two images were acquired at each cardinal gantry angle (-180o, -90o , 0o, 90o) at two opposing collimator angles. The images were exported to the conebeam CT software XVI 4.5 where the difference between the ball bearing position in the XYZ-room coordinates (IEC61217...

  5. Conceptual and ion-optical designs of an isocentric gantry for light-ion cancer therapy

    International Nuclear Information System (INIS)

    Vorobiev, L.G.; Weick, H.; Wollnik, H.

    1998-02-01

    Conceptual and ion-optical designs of an isocentric gantry are presented. The gantry is designed for light-ion therapy using a 6 Tm carbon beam. Its main characteristics are: 5 m overall radius, 1.4 m drift to the patient, 20x10 cm 2 treatment field, and two-direction active parallel scanning of a fine focused pencil beam. To achieve these features, the beam scanners are optimally positioned upstream the last 90 bending section consisting of two 45 sector magnets with 4 oblique field boundaries and different apertures. The gantry concept is a compromise between 'barrel' and 'conical' gantry shapes and is likely the most space-saving configuration of single-plane isocentric gantries. This new so-called 'short barrel' configuration features also small aperture quadruple lenses, low intermediate dispersion and a fully achromatic beam transport system. Its overall dimensions stay close to the size of the existing proton gantries. (orig.)

  6. Electron-photon shower distribution function tables for lead, copper and air absorbers

    CERN Document Server

    Messel, H

    2013-01-01

    Electron-Photon Shower Distribution Function: Tables for Lead, Copper and Air Absorbers presents numerical results of the electron-photon shower distribution function for lead, copper, and air absorbers. Electron or photon interactions, including Compton scattering, elastic Coulomb scattering, and the photo-electric effect, are taken into account in the calculations. This book consists of four chapters and begins with a review of both theoretical and experimental work aimed at deducing the characteristics of the cascade produced from the propagation of high energy electrons and photons through

  7. The accuracy assessment of PPS in fixed beam proton therapy: isocentric rotation movement

    International Nuclear Information System (INIS)

    Li Xinping; Zeng Xianwen; Xu Wenling; Li Jiamin; Lv Mingming

    2005-01-01

    Objective: To assess the accuracy of isocentric rotation movement of Patient Positioning System (PPS) in fixed beam proton therapy. Methods: A 2 mm-diameter radioopaque sphere was positioned above the couch and was aligned to room iso-center (ISO). 11 PPS angles were selected to make isocentric rotation test respectively. The displacement of the sphere to ISO were measured and calculated by Digital Image Positioning System (DIPS) respectively when PPS reached each designed position. Totally four group measurements were repeated at different time. all data were collected and statistical analysis were performed. Results: The maximum shifts are (0.29 ± 0.05) mm, (0.21 ± 0.04) mm and (-0.21 ± 0.04) mm on X, Y, Z axes at - 110 degree PPS position, the absolute displacement of the sphere to ISO is (0.41 ± 0.07) mm(1SD). The minimum shifts are (-0.03 ± 0.05) mm, (0.05 ± 0.05) mm and (0.00 ± 0.00) mm on three principle axes at 30 degree PPS position, the absolute displacement of the sphere to ISO is (0.05 ± 0.06) mm. Conclusion: The isocentric rotation movement is the linchpin to realize multi-angle isocentric irradiation in fixed beamproton therapy. It is a complicated combined movement including PPS rotation and PPS translations. Since the high demand in the of precision of patient positioning, the accuracy of this combined movement played important role in proton therapy. In our tests, all shifts are less than 0.5 mm, can reach the requirement of positioning accuracy in proton therapy. (authors)

  8. MRI gel dosimetry for verification of mono-isocentric junction doses in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Back, S.A.J.; Jayasekera, P.M.; Lepage, M.; Baldock, C.; Menzies, N.; Back, P.

    2000-01-01

    Full text: The use of independent collimators in the abutment of two adjacent treatment volumes, as in head and neck radiation treatments, consists typically of positioning the collimator rotation axis (CRA) at the junction of the volumes, and offsetting each field by its half-field width. This has the effect of positioning one of the collimator jaws at the CRA for each field. However, misalignment of the jaws can lead to variations in dose uniformity in the junction region. We have used gel dosimetry to measure junction doses in three dimensions. PAG gel MRI was used to investigate junction dosimetry for a mono-isocentriic treatment of two orthogonal pairs of opposed (ant/post and lateral) 6 MV x-ray beams. PAG gels in an 11cm diameter cylindrical gel phantom were imaged using a Siemens Vision 1.5 T MRI. The exposures were made using a Philips SL 20 linear accelerator with independent jaws that were known to overlap at the isocentre for sequential abutting offset (within manufacturer's specifications for symmetric fields). X-Omat V films were exposed in mono-directional beams, and optically scanned for comparison. Measurements of off-axis ratios and of relative depth profiles using gel MRI and perpendicular film were in excellent agreement with each other. Measurements through the multi-directional junction at the isocentre are illustrated in the graph, for orthogonal planes centred at the isocentre of the neck phantom. They demonstrate a minimum dose of 75 % of that of the adjacent 'treatment' regions, which agrees closely with the results measured (72%) in the mono-directional case with film. We conclude that this measurement confirms that junction dosimetry at the isocentre measured with perpendicular film for a single direction is a good approximation to the situation in multiple directions. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  9. 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.

  10. Investigation of positron moderator materials for electron-linac-based slow positron beamlines

    International Nuclear Information System (INIS)

    Suzuki, Ryoichi; Ohdaira, Toshiyuki; Uedono, Akira

    1998-01-01

    Positron re-emission properties were studied on moderator materials in order to improve the positron moderation system of electron-linac-based intense slow positron beamlines. The re-emitted positron fraction was measured on tungsten, SiC, GaN, SrTiO 3 , and hydrogen-terminated Si with a variable-energy pulsed positron beam. The results suggested that tungsten is the best material for the primary moderator of the positron beamlines while epitaxially grown n-type 6H-SiC is the best material for the secondary moderator. Defect characterization by monoenergetic positron beams and surface characterization by Auger electron spectroscopy were carried out to clarify the mechanism of tungsten moderator degradation induced by high-energy electron irradiation. The characterization experiments revealed that the degradation is due to both radiation-induced vacancy clusters and surface carbon impurities. For the restoration of degraded tungsten moderators, oxygen treatment at ∼900degC is effective. Furthermore, it was found that oxygen at the tungsten surface inhibits positronium formation; as a result, it can increase the positron re-emission fraction. (author)

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

    International Nuclear Information System (INIS)

    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.; Parmigiani, F.; Placidi, M.; Pirkl, W.; Rimmer, R. A.; Wang, S.

    2003-01-01

    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

  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. Beam-transport study of an isocentric rotating ion gantry with minimum number of quadrupoles

    International Nuclear Information System (INIS)

    Pavlovic, Marius; Griesmayer, Erich; Seemann, Rolf

    2005-01-01

    A beam-transport study of an isocentric gantry for ion therapy is presented. The gantry is designed with the number of quadrupoles down to the theoretical minimum, which is the feature published for the first time in this paper. This feature has been achieved without compromising the ion-optical functions of the beam-transport system that is capable of handling non-symmetric beams (beams with different emittances in vertical and horizontal plane), pencil-beam scanning, double-achromatic optics and beam-size control. Ion-optical properties of the beam-transport system are described, discussed and illustrated by computer simulations performed by the TRANSPORT-code

  14. Isocentric rotational performance of the Elekta Precise Table studied using a USB-microscope

    DEFF Research Database (Denmark)

    Riis, Hans L; Zimmermann, Sune J; Riis, Poul

    2010-01-01

    The isocentric three-dimensional performance of the Elekta Precise Table was investigated. A pointer was attached to the radiation head of the accelerator and positioned at the geometric rotational axis of the head. A USB-microscope was mounted on the treatment tabletop to measure the table...... position relative to the pointer tip. The table performance was mapped in terms of USB-microscope images of the pointer tip at different table angles and load configurations. The USB-microscope was used as a detector to measure the pointer tip positions with a resolution down to 0.01 mm. A new elastic...

  15. Neural stem cell sparing by linac based intensity modulated stereotactic radiotherapy in intracranial tumors

    International Nuclear Information System (INIS)

    Oehler, Julia; Brachwitz, Tim; Wendt, Thomas G; Banz, Nico; Walther, Mario; Wiezorek, Tilo

    2013-01-01

    most from IMSRT (p < 0.001). The feasibility of neural stem cell niches sparing with sophisticated linac based inverse IMSRT with 7 beamlets in an unselected cohort of intracranial tumors in relation to topographic situation has been demonstrated. Clinical relevance testing neurotoxicity remains to be demonstrated

  16. PENELOPE, and algorithm and computer code for Monte Carlo simulation of electron-photon showers

    Energy Technology Data Exchange (ETDEWEB)

    Salvat, F.; Fernandez-Varea, J.M.; Baro, J.; Sempau, J.

    1996-10-01

    The FORTRAN 77 subroutine package PENELOPE performs Monte Carlo simulation of electron-photon showers in arbitrary for a wide energy range, from similar{sub t}o 1 KeV to several hundred MeV. Photon transport is simulated by means of the standard, detailed simulation scheme. Electron and positron histories are generated on the basis of a mixed procedure, which combines detailed simulation of hard events with condensed simulation of soft interactions. A simple geometry package permits the generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces, i.e. planes, spheres cylinders, etc. This report is intended not only to serve as a manual of the simulation package, but also to provide the user with the necessary information to understand the details of the Monte Carlo algorithm.

  17. PENELOPE, an algorithm and computer code for Monte Carlo simulation of electron-photon showers

    Energy Technology Data Exchange (ETDEWEB)

    Salvat, F; Fernandez-Varea, J M; Baro, J; Sempau, J

    1996-07-01

    The FORTRAN 77 subroutine package PENELOPE performs Monte Carlo simulation of electron-photon showers in arbitrary for a wide energy range, from 1 keV to several hundred MeV. Photon transport is simulated by means of the standard, detailed simulation scheme. Electron and positron histories are generated on the basis of a mixed procedure, which combines detailed simulation of hard events with condensed simulation of soft interactions. A simple geometry package permits the generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces, i.e. planes, spheres, cylinders, etc. This report is intended not only to serve as a manual of the simulation package, but also to provide the user with the necessary information to understand the details of the Monte Carlo algorithm. (Author) 108 refs.

  18. Attractive electron correlation in wide band gap semiconductors by electron-photon interaction

    International Nuclear Information System (INIS)

    Takeda, Hiroyuki; Yoshino, Katsumi

    2004-01-01

    We theoretically demonstrate attractive electron correlation in wide band gap semiconductors by electron-photon interaction. At low temperature, wavevectors of electromagnetic waves absorbed in wide band gap semiconductors cannot be neglected for wavevectors of electron waves; that is, electromagnetic waves affect the movements of electrons. In particular, attractive interaction occurs between two electrons when one electron changes from a valence band to a conduction band and the other electron changes from a conduction band to a valence band

  19. Evaluation of beam delivery and ripple filter design for non-isocentric proton and carbon ion therapy.

    Science.gov (United States)

    Grevillot, L; Stock, M; Vatnitsky, S

    2015-10-21

    This study aims at selecting and evaluating a ripple filter design compatible with non-isocentric proton and carbon ion scanning beam treatment delivery for a compact nozzle. The use of non-isocentric treatments when the patient is shifted as close as possible towards the nozzle exit allows for a reduction in the air gap and thus an improvement in the quality of scanning proton beam treatment delivery. Reducing the air gap is less important for scanning carbon ions, but ripple filters are still necessary for scanning carbon ion beams to reduce the number of energy steps required to deliver homogeneous SOBP. The proper selection of ripple filters also allows a reduction in the possible transverse and depth-dose inhomogeneities that could appear in non-isocentric conditions in particular. A thorough review of existing ripple filter designs over the past 16 years is performed and a design for non-isocentric treatment delivery is presented. A unique ripple filter quality index (QIRiFi) independent of the particle type and energy and representative of the ratio between energy modulation and induced scattering is proposed. The Bragg peak width evaluated at the 80% dose level (BPW80) is proposed to relate the energy modulation of the delivered Bragg peaks and the energy layer step size allowing the production of homogeneous SOBP. Gate/Geant4 Monte Carlo simulations have been validated for carbon ion and ripple filter simulations based on measurements performed at CNAO and subsequently used for a detailed analysis of the proposed ripple filter design. A combination of two ripple filters in a series has been validated for non-isocentric delivery and did not show significant transverse and depth-dose inhomogeneities. Non-isocentric conditions allow a significant reduction in the spot size at the patient entrance (up to 350% and 200% for protons and carbon ions with range shifter, respectively), and therefore in the lateral penumbra in the patients.

  20. A mono isocentric radiotherapy technique for craniospinal irradiation using asymmetric jaws

    International Nuclear Information System (INIS)

    Isin, G; Oezyar, E.; Guerdalli, S.; Arslan, G.; Uzal, D.; Atahan, I. L.

    1995-01-01

    Dose distribution across the junction of matching of craniospinal fields (lateral cranial fields and posterior spinal field) is important as severe complications may result if the beams overlap or disease may recurs if the gapping is too conservative. Various techniques have been used to achieve an effective transverse plane match and half-beam block technique is one of these techniques. Here, we describe a mono isocentric technique for the treatment of craniospinal fields using the asymmetric jaws of our linear accelerator (Philips SL-25). Before the clinical application of this non-standard technique, basic dosimetry parameters are evaluated. Asymmetric collimator dose distributions for various asymmetric field sizes were obtained and compared with symmetric dose distributions for 6 MV x-ray. A computerized 3-D water phantom with a pair of ionization chambers (reference and field) was used for dose profiles, isodose distributions and Percentage Depth Dose (PDD) for various asymmetric field sizes and different off axis distances. The measured values of off axis ratios for the interested depths were used in MU calculations. This new mono isocentric technique provides an ideal dose distribution at match-line as there is no need to move the patient during treatment. Use of heavy secondary cerrobend blocks (beam splitters) is eliminated. This technique provides the ease of consequent daily set-up's and fulfills the requirements for a conformal radiotherapy

  1. A simple isocentric technique for irradiation of the breast, chest wall and peripheral lymphatics

    International Nuclear Information System (INIS)

    Podgorsak, E.B.; Gosselin, M.; Pla, M.; Kim, T.H.; Freeman, C.R.

    1984-01-01

    The major problem with the standard technique for irradiation of the breast or chest wall and peripheral lymphatics is field matching at the junction between the supraclavicular and tangential fields. Overdosing or underdosing across the junctions is unavoidable because of beam divergence. Various techniques using a half-blocked supraclavicular field in conjunction with special tangential fields have been introduced recently to eliminate the junction problem; they are, however, complicated, involving couch motions and machine isocentre repositioning when changing from the supraclavicular to the tangential fields. The breast treatment technique used by the authors over the past twelve months utilises a supraclavicular half-blocked field, two tangential half-blocked fields and an optional posterior axillary field. The technique is simple and easy to set up since the same machine isocentre is used for all treatment fields and no couch movement or patient repositioning is required. The same half-block collimator used to define the caudad border of the supraclavicular field is used to define the cephalad edges of the two tangential fields. The margin of error of treatment is reduced and the dose measurements demonstrate excellent dose homogeneity through the entire treatment volume with no overdose or underdose at the field junction. (author)

  2. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI

    DEFF Research Database (Denmark)

    Lynggaard Riis, Hans; Moltke, Lars N; Zimmermann, S. J.

    2016-01-01

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning...... orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability...

  3. 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

  4. Measuring Higgs Boson Associated Lepton Flavour Violation in Electron-Photon Collisions at the ILC

    International Nuclear Information System (INIS)

    Kanemura, Shinya; Tsumura, Koji

    2010-08-01

    We study the LFV Higgs production processes e - γ → l - φ (l = μ, τ ;φ = H,A) as a probe of Higgs mediated LFV couplings at an electron-photon collider, where H and A are extra CP even and odd Higgs bosons, respectively, in the two Higgs doublet model. Under the constraints from the current data of muon and tau rare decay, the cross section can be significantly large. It would improve the experimental upper bounds on the effective LFV coupling constants. In addition, the chirality nature of the LFV Higgs coupling constants can be measured by selecting electron beam polarizations. (author)

  5. Application of the Arbitrarily High Order Method to Coupled Electron Photon Transport

    International Nuclear Information System (INIS)

    Duo, Jose Ignacio

    2004-01-01

    This work is about the application of the Arbitrary High Order Nodal Method to coupled electron photon transport.A Discrete Ordinates code was enhanced and validated which permited to evaluate the advantages of using variable spatial development order per particle.The results obtained using variable spatial development and adaptive mesh refinement following an a posteriori error estimator are encouraging.Photon spectra for clinical accelerator target and, dose and charge depositio profiles are simulated in one-dimensional problems using cross section generated with CEPXS code.Our results are in good agreement with ONELD and MCNP codes

  6. 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

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

    International Nuclear Information System (INIS)

    Cetin, I.A.; Marmara Univ., Ustkaynarca/Pendik; Ates, R.; Dhaens, J.; Storme, G.

    2012-01-01

    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 3 (median, 2.3 cm 3 ) and the median marginal dose was 20 Gy (range, 10.4-22). The median 12-Gy volume was 9.94 cm 3 (range, 0.74-60.09 cm 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 3 ], small volume, and a Pollock-Flickinger score less than 1.49; those predicting excellent outcomes were V12 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 3 (p=0.03) and volume greater than 2 cm 3 (p=0.001), as determined by a univariate analysis. The analyses showed an ROC of 0.66. Conclusion: These data suggest that linac-based radiosurgery is

  8. ITS, TIGER System of Coupled Electron Photon Transport by Monte-Carlo

    International Nuclear Information System (INIS)

    Halbleib, J.A.; Mehlhorn, T.A.; Young, M.F.

    1996-01-01

    1 - Description of program or function: ITS permits a state-of-the-art Monte Carlo solution of linear time-integrated coupled electron/ photon radiation transport problems with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. 2 - Method of solution: Through a machine-portable utility that emulates the basic features of the CDC UPDATE processor, the user selects one of eight codes for running on a machine of one of four (at least) major vendors. With the ITS-3.0 release the PSR-0245/UPEML package is included to perform these functions. The ease with which this utility is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is maximized by employing the best available cross sections and sampling distributions, and the most complete physical model for describing the production and transport of the electron/ photon cascade from 1.0 GeV down to 1.0 keV. Flexibility of construction permits the codes to be tailored to specific applications and the capabilities of the codes to be extended to more complex applications through update procedures. 3 - Restrictions on the complexity of the problem: - Restrictions and/or limitations for ITS depend upon the local operating system

  9. ITS Version 6 : the integrated TIGER series of coupled electron/photon Monte Carlo transport codes.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

    2008-04-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of lineartime-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 6, the latest version of ITS, contains (1) improvements to the ITS 5.0 codes, and (2) conversion to Fortran 90. The general user friendliness of the software has been enhanced through memory allocation to reduce the need for users to modify and recompile the code.

  10. Single Fraction Versus Fractionated Linac-Based Stereotactic Radiotherapy for Vestibular Schwannoma: A Single-Institution Experience

    Energy Technology Data Exchange (ETDEWEB)

    Collen, Christine, E-mail: ccollen@uzbrussel.be [Department of Radiation Oncology, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); Ampe, Ben [Department of Neurosurgery, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); Gevaert, Thierry [Department of Radiation Oncology, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); Moens, Maarten [Department of Neurosurgery, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); Linthout, Nadine; De Ridder, Mark; Verellen, Dirk [Department of Radiation Oncology, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); D' Haens, Jean [Department of Neurosurgery, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium); Storme, Guy [Department of Radiation Oncology, UZ Brussel, Vrije Universiteit Brussel (VUB), Laarbeeklaan 101, 1090 Brussels (Belgium)

    2011-11-15

    Purpose: To evaluate and compare outcomes for patients with vestibular schwannoma (VS) treated in a single institution with linac-based stereotactic radiosurgery (SRS) or by fractionated stereotactic radiotherapy (SRT). Methods and Materials: One hundred and nineteen patients (SRS = 78, SRT = 41) were treated. For both SRS and SRT, beam shaping is performed by a mini-multileaf collimator. For SRS, a median single dose of 12.5 Gy (range, 11-14 Gy), prescribed to the 80% isodose line encompassing the target, was applied. Of the 42 SRT treatments, 32 treatments consisted of 10 fractions of 3-4 Gy, and 10 patients received 25 sessions of 2 Gy, prescribed to the 100% with the 95% isodose line encompassing the planning target volume. Mean largest tumor diameter was 16.6 mm in the SRS and 24.6 mm in the SRT group. Local tumor control, cranial nerve toxicity, and preservation of useful hearing were recorded. Any new treatment-induced cranial nerve neuropathy was scored as a complication. Results: Median follow-up was 62 months (range, 6-136 months), 5 patients progressed, resulting in an overall 5-year local tumor control of 95%. The overall 5-year facial nerve preservation probability was 88% and facial nerve neuropathy was statistically significantly higher after SRS, after prior surgery, for larger tumors, and in Koos Grade {>=}3. The overall 5-year trigeminal nerve preservation probability was 96%, not significantly influenced by any of the risk factors. The overall 4-year probability of preservation of useful hearing (Gardner-Robertson score 1 or 2) was 68%, not significantly different between SRS or SRT (59% vs. 82%, p = 0.089, log rank). Conclusion: Linac-based RT results in good local control and acceptable clinical outcome in small to medium-sized vestibular schwannomas (VSs). Radiosurgery for large VSs (Koos Grade {>=}3) remains a challenge because of increased facial nerve neuropathy.

  11. SPHERE: a spherical-geometry multimaterial electron/photon Monte Carlo transport code

    International Nuclear Information System (INIS)

    Halbleib, J.A. Sr.

    1977-06-01

    SPHERE provides experimenters and theorists with a method for the routine solution of coupled electron/photon transport through multimaterial configurations possessing spherical symmetry. Emphasis is placed upon operational simplicity without sacrificing the rigor of the model. SPHERE combines condensed-history electron Monte Carlo with conventional single-scattering photon Monte Carlo in order to describe the transport of all generations of particles from several MeV down to 1.0 and 10.0 keV for electrons and photons, respectively. The model is more accurate at the higher energies, with a less rigorous description of the particle cascade at energies where the shell structure of the transport media becomes important. Flexibility of construction permits the user to tailor the model to specific applications and to extend the capabilities of the model to more sophisticated applications through relatively simple update procedures. 8 figs., 3 tables

  12. Parallel FE Electron-Photon Transport Analysis on 2-D Unstructured Mesh

    International Nuclear Information System (INIS)

    Drumm, C.R.; Lorenz, J.

    1999-01-01

    A novel solution method has been developed to solve the coupled electron-photon transport problem on an unstructured triangular mesh. Instead of tackling the first-order form of the linear Boltzmann equation, this approach is based on the second-order form in conjunction with the conventional multi-group discrete-ordinates approximation. The highly forward-peaked electron scattering is modeled with a multigroup Legendre expansion derived from the Goudsmit-Saunderson theory. The finite element method is used to treat the spatial dependence. The solution method is unique in that the space-direction dependence is solved simultaneously, eliminating the need for the conventional inner iterations, a method that is well suited for massively parallel computers

  13. Electron-photon angular correlation measurements for the 2 1P state of helium

    International Nuclear Information System (INIS)

    Slevin, J.; Porter, H.Q.; Eminyan, M.; Defrance, A.; Vassilev, G.

    1980-01-01

    Electron-photon angular correlations have been measured by detecting in delayed coincidence, electrons inelastically scattered from helium and photons emitted in decays from the 2 1 P state at incident electron energies of 60 and 80 eV. Analysis of the data yields values for the ratio lambda of the differential cross sections for magnetic sublevel excitations and the phase difference X between the corresponding probability amplitudes. The measurements extend over the angular range 10-120 0 of electron scattering angles. The present data are in good agreement with the experimental results of Hollywood et al, (J. Phys. B.; 12: 819 (1979)), and show a marked discrepancy at large scattering angles with the recent data of Steph and Golde. (Phys. Rev.; A in press (1980)). The experimental results are compared with some recent theories. (author)

  14. Space applications of the MITS electron-photon Monte Carlo transport code system

    International Nuclear Information System (INIS)

    Kensek, R.P.; Lorence, L.J.; Halbleib, J.A.; Morel, J.E.

    1996-01-01

    The MITS multigroup/continuous-energy electron-photon Monte Carlo transport code system has matured to the point that it is capable of addressing more realistic three-dimensional adjoint applications. It is first employed to efficiently predict point doses as a function of source energy for simple three-dimensional experimental geometries exposed to simulated uniform isotropic planar sources of monoenergetic electrons up to 4.0 MeV. Results are in very good agreement with experimental data. It is then used to efficiently simulate dose to a detector in a subsystem of a GPS satellite due to its natural electron environment, employing a relatively complex model of the satellite. The capability for survivability analysis of space systems is demonstrated, and results are obtained with and without variance reduction

  15. Single Production of Excited Neutrino at Clic based Electron Photon Colliders

    International Nuclear Information System (INIS)

    Kirca, Z.

    2004-01-01

    The discovery of excited quarks and leptons, as predicted by composite models, would supply convincing evidence for substructure of fermions. Electron-photon interactions at very high energies provide ideal conditions to look for excited states of first generations offermions. In particular, in magnetic- transition coupling the electron to a gauge bo son would allow for single production of excited neutrinos (ν * ) through t-channel W boson exchange. In this work, (ν * ) production followed by the electroweak radiative decays ν * →νγ, ν * →eW, ν * →νZ is presented. The production cross sections and P T distributions of excited neutrino are studied for CLlC

  16. CEPXS/ONELD: A one-dimensional coupled electron-photon discrete ordinates code package

    International Nuclear Information System (INIS)

    Lorence, L.J. Jr.; Morel, J.E.

    1992-01-01

    CEPXS/ONELD is a discrete ordinates transport code package that can model the electron-photon cascade from 100 MeV to 1 keV. The CEPXS code generates fully-coupled multigroup-Legendre cross section data. This data is used by the general-purpose discrete ordinates code, ONELD, which is derived from the Los Alamos ONEDANT and ONBTRAN codes. Version 1.0 of CEPXS/ONELD was released in 1989 and has been primarily used to analyze the effect of radiation environments on electronics. Version 2.0 is under development and will include user-friendly features such as the automatic selection of group structure, spatial mesh structure, and S N order

  17. ITS - The integrated TIGER series of coupled electron/photon Monte Carlo transport codes

    International Nuclear Information System (INIS)

    Halbleib, J.A.; Mehlhorn, T.A.

    1985-01-01

    The TIGER series of time-independent coupled electron/photon Monte Carlo transport codes is a group of multimaterial, multidimensional codes designed to provide a state-of-the-art description of the production and transport of the electron/photon cascade. The codes follow both electrons and photons from 1.0 GeV down to 1.0 keV, and the user has the option of combining the collisional transport with transport in macroscopic electric and magnetic fields of arbitrary spatial dependence. Source particles can be either electrons or photons. The most important output data are (a) charge and energy deposition profiles, (b) integral and differential escape coefficients for both electrons and photons, (c) differential electron and photon flux, and (d) pulse-height distributions for selected regions of the problem geometry. The base codes of the series differ from one another primarily in their dimensionality and geometric modeling. They include (a) a one-dimensional multilayer code, (b) a code that describes the transport in two-dimensional axisymmetric cylindrical material geometries with a fully three-dimensional description of particle trajectories, and (c) a general three-dimensional transport code which employs a combinatorial geometry scheme. These base codes were designed primarily for describing radiation transport for those situations in which the detailed atomic structure of the transport medium is not important. For some applications, it is desirable to have a more detailed model of the low energy transport. The system includes three additional codes that contain a more elaborate ionization/relaxation model than the base codes. Finally, the system includes two codes that combine the collisional transport of the multidimensional base codes with transport in macroscopic electric and magnetic fields of arbitrary spatial dependence

  18. Present status of the low energy linac-based slow positron beam and positronium spectrometer in Saclay

    Science.gov (United States)

    Liszkay, L.; Comini, P.; Corbel, C.; Debu, P.; Grandemange, P.; Pérez, P.; Rey, J.-M.; Reymond, J.-M.; Ruiz, N.; Sacquin, Y.; Vallage, B.

    2014-04-01

    A new slow positron beamline featuring a large acceptance positronium lifetime spectrometer has been constructed and tested at the linac-based slow positron source at IRFU CEA Saclay, France. The new instrument will be used in the development of a dense positronium target cloud for the GBAR experiment. The GBAR project aims at precise measurement of the gravitational acceleration of antihydrogen in the gravitational field of the Earth. Beyond application in fundamental science, the positron spectrometer will be used in materials research, for testing thin porous films and layers by means of positronium annihilation. The slow positron beamline is being used as a test bench to develop further instrumentation for positron annihilation spectroscopy (Ps time-of-flight, pulsed positron beam). The positron source is built on a low energy linear electron accelerator (linac). The 4.3 MeV electron energy used is well below the photoneutron threshold, making the source a genuine on-off device, without remaining radioactivity. The spectrometer features large BGO (Bismuth Germanate) scintillator detectors, with sufficiently large acceptance to detect all ortho-positronium annihilation lifetime components (annihilation in vacuum and in nanopores).

  19. Quality assurance system to correct for errors arising from couch rotation in linac-based stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Brezovich, Ivan A.; Pareek, Prem N.; Plott, W. Eugene; Jennelle, Richard L. S.

    1997-01-01

    Purpose: The purpose of this project was the development of a quality assurance (QA) system that would provide geographically accurate targeting for linac-based stereotactic radiosurgery (LBSR). Methods and Materials: The key component of our QA system is a novel device (Alignment Tool) for expedient measurement of gantry and treatment table excursions (wobble) during rotation. The Alignment Tool replaces the familiar pencil-shaped pointers with a ball pointer that is used with the field light of the accelerator to indicate alignment of beam and target. Wobble is measured prior to each patient treatment and analyzed together with the BRW coordinates of the target by a spreadsheet. The corrections required to compensate for any imprecision are identified, and a printout generated indicating the floor stand coordinates for each couch angle used to place the target at isocenter. Results: The Alignment Tool has an inherent accuracy of measurement better than 0.1 mm. The overall targeting error of our QA method, found by evaluating 177 target simulator films of 55 foci in 40 randomly selected patients, was 0.47 ± 0.23 mm. The Alignment Tool was also valuable during installation of the floor stand and a supplemental collimator for the accelerator. Conclusions: The QA procedure described allows accurate targeting in LBSR, even when couch rotation is imprecise. The Alignment Tool can facilitate the installation of any stereotactic irradiation system, and can be useful for annual QA checks as well as in the installation and commissioning of new accelerators

  20. A study into the review and verification of breast images treated with isocentric technique

    International Nuclear Information System (INIS)

    Mitchell, Fiona

    2007-01-01

    In radiation therapy practice, portal imaging is a common occurrence. Radiation Oncologists want to be able to view the actual treatment port and compare it to the simulated view for quality assurance. Historically, this has been the domain of oncologists only but with the changes in imaging technology, this area of practice is now more commonly shared with the radiation therapists. Purpose: The primary aim of this study was to compare the Radiation Therapists' result versus the Radiation Oncologists' practice of review and verification of electronic portal imaging in the treatment of breast cancer. A secondary result was enhancement of electronic portal imaging use. Methods: The study was divided into two parts. Part 1 reviewed imaging of tangential breast treatment and part 2 reviewed mono-isocentric four-field breast technique. The review and verification of the images were conducted by the Radiation Therapists and Radiation Oncologists and their subsequent results were compared. Results: Overall the Radiation Oncologist agreed with 96.9% of the images approved by the Radiation Therapists. This makes for a rejection rate of 3.1%. In general, Radiation Therapists adhered to the guidelines more closely than the Radiation Oncologist hence the rejection rate of Radiation Therapists was greater than the Radiation Oncologist by 7.0%. Conclusions: The practice of electronic portal imaging review and verification in the treatment of breast cancer can be streamlined and achieved more efficiently. The Radiation Therapists consistently demonstrated their ability to review and verify the portal images, as equivalent to the Radiation Oncologist. Given the high standard of accuracy demonstrated the process of portal image review should be transferred to the Radiation Therapist. This transfer leads to reduction in duplicity of task, an increase in the use of technology, an improvement in efficiencies, and an increase in the quality of care, which will potentially lead to more

  1. Performance of a Novel Repositioning Head Frame for Gamma Knife Perfexion and Image-Guided Linac-Based Intracranial Stereotactic Radiotherapy

    International Nuclear Information System (INIS)

    Ruschin, Mark; Nayebi, Nazanin; Carlsson, Per; Brown, Kevin

    2010-01-01

    Purpose: To evaluate the geometric positioning and immobilization performance of a vacuum bite-block repositioning head frame (RHF) system for Perfexion (PFX-SRT) and linac-based intracranial image-guided stereotactic radiotherapy (SRT). Methods and Materials: Patients with intracranial tumors received linac-based image-guided SRT using the RHF for setup and immobilization. Three hundred thirty-three fractions of radiation were delivered in 12 patients. The accuracy of the RHF was estimated for linac-based SRT with online cone-beam CT (CBCT) and for PFX-SRT with a repositioning check tool (RCT) and offline CBCT. The RCT's ability to act as a surrogate for anatomic position was estimated through comparison to CBCT image matching. Immobilization performance was evaluated daily with pre- and postdose delivery CBCT scans and RCT measurements. Results: The correlation coefficient between RCT- and CBCT-reported displacements was 0.59, 0.75, 0.79 (Right, Superior, and Anterior, respectively). For image-guided linac-based SRT, the mean three-dimensional (3D) setup error was 0.8 mm with interpatient (Σ) and interfraction (σ) variations of 0.1 and 0.4 mm, respectively. For PFX-SRT, the initial, uncorrected mean 3D positioning displacement in stereotactic coordinates was 2.0 mm, with Σ = 1.1 mm and σ = 0.8 mm. Considering only RCT setups o in pitch. The mean 3D intrafraction motion was 0.4 ± 0.3 mm. Conclusion: The RHF provides excellent immobilization for intracranial SRT and PFX-SRT. Some small systematic uncertainties in stereotactic positioning exist and must be considered when generating PFX-SRT treatment plans. The RCT provides reasonable surrogacy for internal anatomic displacement.

  2. Anisotropic Electron-Photon and Electron-Phonon Interactions in Black Phosphorus.

    Science.gov (United States)

    Ling, Xi; Huang, Shengxi; Hasdeo, Eddwi H; Liang, Liangbo; Parkin, William M; Tatsumi, Yuki; Nugraha, Ahmad R T; Puretzky, Alexander A; Das, Paul Masih; Sumpter, Bobby G; Geohegan, David B; Kong, Jing; Saito, Riichiro; Drndic, Marija; Meunier, Vincent; Dresselhaus, Mildred S

    2016-04-13

    Orthorhombic black phosphorus (BP) and other layered materials, such as gallium telluride (GaTe) and tin selenide (SnSe), stand out among two-dimensional (2D) materials owing to their anisotropic in-plane structure. This anisotropy adds a new dimension to the properties of 2D materials and stimulates the development of angle-resolved photonics and electronics. However, understanding the effect of anisotropy has remained unsatisfactory to date, as shown by a number of inconsistencies in the recent literature. We use angle-resolved absorption and Raman spectroscopies to investigate the role of anisotropy on the electron-photon and electron-phonon interactions in BP. We highlight, both experimentally and theoretically, a nontrivial dependence between anisotropy and flake thickness and photon and phonon energies. We show that once understood, the anisotropic optical absorption appears to be a reliable and simple way to identify the crystalline orientation of BP, which cannot be determined from Raman spectroscopy without the explicit consideration of excitation wavelength and flake thickness, as commonly used previously.

  3. Self-Adjoint Angular Flux Equation for Coupled Electron-Photon Transport

    International Nuclear Information System (INIS)

    Liscum-Powell, J.L.; Lorence, L.J. Jr.; Morel, J.E.; Prinja, A.K.

    1999-01-01

    Recently, Morel and McGhee described an alternate second-order form of the transport equation called the self adjoint angular flux (SAAF) equation that has the angular flux as its unknown. The SAAF formulation has all the advantages of the traditional even- and odd-parity self-adjoint equations, with the added advantages that it yields the full angular flux when it is numerically solved, it is significantly easier to implement reflective and reflective-like boundary conditions, and in the appropriate form it can be solved in void regions. The SAAF equation has the disadvantage that the angular domain is the full unit sphere and, like the even- and odd- parity form, S n source iteration cannot be implemented using the standard sweeping algorithm. Also, problems arise in pure scattering media. Morel and McGhee demonstrated the efficacy of the SAAF formulation for neutral particle transport. Here we apply the SAAF formulation to coupled electron-photon transport problems using multigroup cross-sections from the CEPXS code and S n discretization

  4. Self-adjoint angular flux equation for coupled electron-photon transport

    International Nuclear Information System (INIS)

    Liscum-Powell, J.L.; Prinja, A.K.; Morel, J.E.; Lorence, L.J. Jr.

    1999-01-01

    Recently, Morel and McGhee described an alternate second-order form of the transport equation called the self-adjoint angular flux (SAAF) equation that has the angular flux as its unknown. The SAAF formulation has all the advantages of the traditional even- and odd-parity self-adjoint equations, with the added advantages that it yields the full angular flux when it is numerically solved, it is significantly easier to implement reflective and reflective-like boundary conditions, and in the appropriate form it can be solved in void regions. The SAAF equation has the disadvantage that the angular domain is the full unit sphere, and, like the even- and odd-parity form, S n source iteration cannot be implemented using the standard sweeping algorithm. Also, problems arise in pure scattering media. Morel and McGhee demonstrated the efficacy of the SAAF formulation for neutral particle transport. Here, the authors apply the SAAF formulation to coupled electron-photon transport problems using multigroup cross sections from the CEPXS code and S n discretization

  5. Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

    International Nuclear Information System (INIS)

    Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

    2010-01-01

    During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

  6. Poster — Thur Eve — 55: An automated XML technique for isocentre verification on the Varian TrueBeam

    International Nuclear Information System (INIS)

    Asiev, Krum; Mullins, Joel; DeBlois, François; Liang, Liheng; Syme, Alasdair

    2014-01-01

    Isocentre verification tests, such as the Winston-Lutz (WL) test, have gained popularity in the recent years as techniques such as stereotactic radiosurgery/radiotherapy (SRS/SRT) treatments are more commonly performed on radiotherapy linacs. These highly conformal treatments require frequent monitoring of the geometrical accuracy of the isocentre to ensure proper radiation delivery. At our clinic, the WL test is performed by acquiring with the EPID a collection of 8 images of a WL phantom fixed on the couch for various couch/gantry angles. This set of images is later analyzed to determine the isocentre size. The current work addresses the acquisition process. A manual WL test acquisition performed by and experienced physicist takes in average 25 minutes and is prone to user manipulation errors. We have automated this acquisition on a Varian TrueBeam STx linac (Varian, Palo Alto, USA). The Varian developer mode allows the execution of custom-made XML script files to control all aspects of the linac operation. We have created an XML-WL script that cycles through each couch/gantry combinations taking an EPID image at each position. This automated acquisition is done in less than 4 minutes. The reproducibility of the method was verified by repeating the execution of the XML file 5 times. The analysis of the images showed variation of the isocenter size less than 0.1 mm along the X, Y and Z axes and compares favorably to a manual acquisition for which we typically observe variations up to 0.5 mm

  7. Extended distance non-isocentric treatment in stereotactic body radiation therapy (SBRT for lung cancer

    Directory of Open Access Journals (Sweden)

    Long Huang

    2015-03-01

    Full Text Available Purpose: To obtain the maximum differential non-coplanar beams angle for a faster dose dropping outside Plan Target Volume (PTV for lung cancer treated by Stereotactic body radiation therapy (SBRT, an extended distance non-isocentric (EDNI treatment method was explored and developed.Methods: The EDNI requires delivering of the treatment beam at 120 cm or farther for sauce axial distance (SAD instead of standard 100 cm. This change provides a more compact dose distribution around PTV and the lower toxicity to organs at risk (OAR due to benefit of 120 cm SAD and more choice of beam and couch angle. A hand calculation formula for the translation between 100 SAD and EDNI was used to verify the treatment plan results. A phantom for end to end study based on this EDNI technique was used to compare with standard 100 SAD deliveries for SBRT. Three patients who underwent SBRT treatment were randomly chosen to demonstrate the benefits of EDNI technique. These treatment re-plans were applied to EDNI and evaluated for conformal index (CI of PTV, R50% of PTV, 2 cm distance (D2cm of PTV and Maximum dose (Dmaxof OARs to compare with original clinical plans.Results: All of the cases delivered by the EDNI technique satisfied dose requirements of RTOG 0263 and showed a faster dose dropping outside of PTV than standard SAD deliveries. The distance from PTV after 1.5 cm for the EDNI technique had a smaller maximum dose and much lower standard deviation for dose distribution. The EDNI applied plans for patients showed less R50% and D2cm of PTV (P≤ 0.05, also similar results for Dmax of esophagus, trachea and spinal cord.Conclusion: The EDNI method enhances the capabilities of linear accelerators as far as the increased gradient of dose drop-off outside of PTV is concerned. More angular separation between beams leads to more compact dose distributions, which allow decreasing volume of high dose exposure in SBRT treatments and better dose distribution on sensitive

  8. On mixed electron-photon radiation therapy optimization using the column generation approach.

    Science.gov (United States)

    Renaud, Marc-André; Serban, Monica; Seuntjens, Jan

    2017-08-01

    Despite considerable increase in the number of degrees of freedom handled by recent radiotherapy optimisation algorithms, treatments are still typically delivered using a single modality. Column generation is an iterative method for solving large optimisation problems. It is well suited for mixed-modality (e.g., photon-electron) optimisation as the aperture shaping and modality selection problem can be solved rapidly, and the performance of the algorithm scales favourably with increasing degrees of freedom. We demonstrate that the column generation method applied to mixed photon-electron planning can efficiently generate treatment plans and investigate its behaviour under different aperture addition schemes. Column generation was applied to the problem of mixed-modality treatment planning for a chest wall case and a leg sarcoma case. 6 MV beamlets (100 cm SAD) were generated for the photon components along with 5 energies for electron beamlets (6, 9, 12, 16 and 20 MeV), simulated as shortened-SAD (80 cm) beams collimated with a photon MLC. For the chest wall case, IMRT-only, modulated electron radiation therapy (MERT)-only, and mixed electron-photon (MBRT) treatment plans were created using the same planning criteria. For the sarcoma case, MBRT and MERT plans were created to study the behaviour of the algorithm under two different sets of planning criteria designed to favour specific modalities. Finally, the efficiency and plan quality of four different aperture addition schemes was analysed by creating chest wall MBRT treatment plans which incorporate more than a single aperture per iteration of the column generation loop based on a heuristic aperture ranking scheme. MBRT plans produced superior target coverage and homogeneity relative to IMRT and MERT plans created using the same optimisation criteria, all the while preserving the normal tissue-sparing advantages of electron therapy. Adjusting the planning criteria to favour a specific modality in the sarcoma

  9. Monolithic Ge-on-Si lasers for large-scale electronic-photonic integration

    Science.gov (United States)

    Liu, Jifeng; Kimerling, Lionel C.; Michel, Jurgen

    2012-09-01

    A silicon-based monolithic laser source has long been envisioned as a key enabling component for large-scale electronic-photonic integration in future generations of high-performance computation and communication systems. In this paper we present a comprehensive review on the development of monolithic Ge-on-Si lasers for this application. Starting with a historical review of light emission from the direct gap transition of Ge dating back to the 1960s, we focus on the rapid progress in band-engineered Ge-on-Si lasers in the past five years after a nearly 30-year gap in this research field. Ge has become an interesting candidate for active devices in Si photonics in the past decade due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In 2007, we proposed combing tensile strain with n-type doping to compensate the energy difference between the direct and indirect band gap of Ge, thereby achieving net optical gain for CMOS-compatible diode lasers. Here we systematically present theoretical modeling, material growth methods, spontaneous emission, optical gain, and lasing under optical and electrical pumping from band-engineered Ge-on-Si, culminated by recently demonstrated electrically pumped Ge-on-Si lasers with >1 mW output in the communication wavelength window of 1500-1700 nm. The broad gain spectrum enables on-chip wavelength division multiplexing. A unique feature of band-engineered pseudo-direct gap Ge light emitters is that the emission intensity increases with temperature, exactly opposite to conventional direct gap semiconductor light-emitting devices. This extraordinary thermal anti-quenching behavior greatly facilitates monolithic integration on Si microchips where temperatures can reach up to 80 °C during operation. The same band-engineering approach can be extended to other pseudo-direct gap semiconductors, allowing us to achieve efficient light emission at wavelengths previously

  10. A simplified spherical harmonic method for coupled electron-photon transport calculations

    International Nuclear Information System (INIS)

    Josef, J.A.

    1996-12-01

    In this thesis we have developed a simplified spherical harmonic method (SP N method) and associated efficient solution techniques for 2-D multigroup electron-photon transport calculations. The SP N method has never before been applied to charged-particle transport. We have performed a first time Fourier analysis of the source iteration scheme and the P 1 diffusion synthetic acceleration (DSA) scheme applied to the 2-D SP N equations. Our theoretical analyses indicate that the source iteration and P 1 DSA schemes are as effective for the 2-D SP N equations as for the 1-D S N equations. Previous analyses have indicated that the P 1 DSA scheme is unstable (with sufficiently forward-peaked scattering and sufficiently small absorption) for the 2-D S N equations, yet is very effective for the 1-D S N equations. In addition, we have applied an angular multigrid acceleration scheme, and computationally demonstrated that it performs as well for the 2-D SP N equations as for the 1-D S N equations. It has previously been shown for 1-D S N calculations that this scheme is much more effective than the DSA scheme when scattering is highly forward-peaked. We have investigated the applicability of the SP N approximation to two different physical classes of problems: satellite electronics shielding from geomagnetically trapped electrons, and electron beam problems. In the space shielding study, the SP N method produced solutions that are accurate within 10% of the benchmark Monte Carlo solutions, and often orders of magnitude faster than Monte Carlo. We have successfully modeled quasi-void problems and have obtained excellent agreement with Monte Carlo. We have observed that the SP N method appears to be too diffusive an approximation for beam problems. This result, however, is in agreement with theoretical expectations

  11. Measurement of cone beam CT coincidence with megavoltage isocentre and image sharpness using the QUASAR Penta-Guide phantom.

    Science.gov (United States)

    Sykes, J R; Lindsay, R; Dean, C J; Brettle, D S; Magee, D R; Thwaites, D I

    2008-10-07

    For image-guided radiotherapy (IGRT) systems based on cone beam CT (CBCT) integrated into a linear accelerator, the reproducible alignment of imager to x-ray source is critical to the registration of both the x-ray-volumetric image with the megavoltage (MV) beam isocentre and image sharpness. An enhanced method of determining the CBCT to MV isocentre alignment using the QUASAR Penta-Guide phantom was developed which improved both precision and accuracy. This was benchmarked against our existing method which used software and a ball-bearing (BB) phantom provided by Elekta. Additionally, a method of measuring an image sharpness metric (MTF(50)) from the edge response function of a spherical air cavity within the Penta-Guide phantom was developed and its sensitivity was tested by simulating misalignments of the kV imager. Reproducibility testing of the enhanced Penta-Guide method demonstrated a systematic error of <0.2 mm when compared to the BB method with near equivalent random error (s=0.15 mm). The mean MTF(50) for five measurements was 0.278+/-0.004 lp mm(-1) with no applied misalignment. Simulated misalignments exhibited a clear peak in the MTF(50) enabling misalignments greater than 0.4 mm to be detected. The Penta-Guide phantom can be used to precisely measure CBCT-MV coincidence and image sharpness on CBCT-IGRT systems.

  12. Electron photon spectra at atmospheric depths 260 and 400 gm/cm2 derived from the Goddard primary proton spectrum using Fermilab data and usual cascade theory

    International Nuclear Information System (INIS)

    Bhattacharyya, D.P.; Gautam, V.P.

    1982-01-01

    The integral electron photon spectra of cosmic rays at airplane altitude and Lenin Peak (altitudes 260 and 400 g-cm -2 air) have been estimated from the primary proton spectrum of Goddard Space Flight Group using Fermilab data of pp→π +- +X and conventional cascade theory. The derived electron-photon spectra fits well the experimental data of Ohta et al. (1975) and Cherdyntseva and Nikol'skii (1976) for energies above 4 TeV

  13. Electron/photon matched field technique for treatment of orbital disease

    International Nuclear Information System (INIS)

    Arthur, Douglas W.; Zwicker, Robert D.; Garmon, Pamela W.; Huang, David T.; Schmidt-Ullrich, Rupert K.

    1997-01-01

    an unmodified photon field edge is matched with the fall-off of the electron field at the 50% isodose lines. By modifying the penumbra, the dose variation is reduced to ±2%. Treatment setup accuracy is essential. Conclusions: The electron/photon matched field technique offers a uniform isodose distribution for treatment of the orbit that has not been previously achieved. With this technique a homogeneous dose can be delivered to the entire orbit while avoiding a significant dose to the anterior segment and minimizing the risk of morbidity

  14. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kosunen, A

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?){sup water} {sub air}, in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in {sup 60}Co gamma beams. In photon beam dosimetry (S I ?){sup water} {sub air} can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation

  15. Metrology and quality of radiation therapy dosimetry of electron, photon and epithermal neutron beams

    International Nuclear Information System (INIS)

    Kosunen, A.

    1999-08-01

    In radiation therapy using electron and photon beams the dosimetry chain consists of several sequential phases starting by the realisation of the dose quantity in the Primary Standard Dosimetry Laboratory and ending to the calculation of the dose to a patient. A similar procedure can be described for the dosimetry of epithermal neutron beams in boron neutron capture therapy (BNCT). To achieve the required accuracy of the dose delivered to a patient the quality of all steps in the dosimetry procedure has to be considered. This work is focused on two items in the dosimetry chains: the determination of the dose in the reference conditions and the evaluation of the accuracy of dose calculation methods. The issues investigated and discussed in detail are: a)the calibration methods of plane parallel ionisation chambers used in electron beam dosimetry, (b) the specification of the critical dosimetric parameter i.e. the ratio of stopping powers for water to air, (S I ?) water air , in photon beams, (c) the feasibility of the twin ionization chamber technique for dosimetry in epithermal neutron beams applied to BNCT and (d) the determination accuracy of the calculated dose distributions in phantoms in electron, photon, and epithermal neutron beams. The results demonstrate that up to a 3% improvement in the consistency of dose determinations in electron beams is achieved by the calibration of plane parallel ionisation chambers in high energy electron beams instead of calibrations in 60 Co gamma beams. In photon beam dosimetry (S I ?) water air can be determined with an accuracy of 0.2% using the percentage dose at the 10 cm depth, %dd(10), as a beam specifier. The use of %odd(10) requires the elimination of the electron contamination in the photon beam. By a twin ionisation chamber technique the gamma dose can be determined with uncertainty of 6% (1 standard deviation) and the total neutron dose with an uncertainty of 15 to 20% (1 standard deviation). To improve the accuracy

  16. ITS Version 3.0: The Integrated TIGER Series of coupled electron/photon Monte Carlo transport codes

    International Nuclear Information System (INIS)

    Halbleib, J.A.; Kensek, R.P.; Valdez, G.D.; Mehlhorn, T.A.; Seltzer, S.M.; Berger, M.J.

    1993-01-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields. It combines operational simplicity and physical accuracy in order to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Flexibility of construction permits tailoring of the codes to specific applications and extension of code capabilities to more complex applications through simple update procedures

  17. ITS Version 3.0: The Integrated TIGER Series of coupled electron/photon Monte Carlo transport codes

    Energy Technology Data Exchange (ETDEWEB)

    Halbleib, J.A.; Kensek, R.P.; Valdez, G.D.; Mehlhorn, T.A. [Sandia National Labs., Albuquerque, NM (United States); Seltzer, S.M.; Berger, M.J. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Ionizing Radiation Div.

    1993-06-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields. It combines operational simplicity and physical accuracy in order to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Flexibility of construction permits tailoring of the codes to specific applications and extension of code capabilities to more complex applications through simple update procedures.

  18. Graviton production by two photon and electron-photon processes in Kaluza-Klein theories with large extra dimensions

    International Nuclear Information System (INIS)

    Atwood, David; Bar-Shalom, Shaouly; Soni, Amarjit

    2000-01-01

    We consider the production of gravitons via two photon and electron-photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We show that at electron-positron colliders, the processes l + l - →l + l - +graviton, with l=e, μ, can lead to a new signal of low energy gravity of the form l + l - →l + l - +missing energy which is well above the standard model background. For example, with two extra dimensions, at the Next Linear Collider with a center of mass energy of 500 or 1000 GeV, hundreds to thousands such l + l - +graviton events may be produced if the scale of the gravitational interactions, M D , is around a few TeV. At a gamma-electron collider, more stringent bounds may be placed on M D via the related reaction e - γ→e - G. For instance, if a 1 TeV e + e - collider is converted to an electron-photon collider, a bound of ∼10(14) TeV may be placed on the scale M D if the number of extra dimensions δ=2, while a bound of ∼4(5) TeV may be placed if δ=4, with unpolarized (right polarized) electron beams. (c) 2000 The American Physical Society

  19. Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

    Directory of Open Access Journals (Sweden)

    Kazuhisa Nakajima

    2014-12-01

    Full Text Available We present a new external-beam radiation therapy system using very-high-energy (VHE electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

  20. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

    International Nuclear Information System (INIS)

    Hsi, Wen C.; Zeidan, Omar A.; Law, Aaron; Schreuder, Andreas N.

    2014-01-01

    Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

  1. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hsi, Wen C., E-mail: Wen.Hsi@Mclaren.org, E-mail: Wenchien.hsi@sphic.org.cn; Zeidan, Omar A., E-mail: omar.zeidan@orlandohealth.com [ProCure Proton Therapy Center, Oklahoma City, Oklahoma 73142 (United States); Law, Aaron; Schreuder, Andreas N., E-mail: niek.schreuder@provisionhp.com [ProCure Training and Development Center, Bloomington, Indiana 47404 (United States)

    2014-08-15

    Purpose: An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. Methods: The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. Results: For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted

  2. Utilization of optical tracking to validate a software-driven isocentric approach to robotic couch movements for proton radiotherapy.

    Science.gov (United States)

    Hsi, Wen C; Law, Aaron; Schreuder, Andreas N; Zeidan, Omar A

    2014-08-01

    An optical tracking and positioning system (OTPS) was developed to validate the software-driven isocentric (SDI) approach to control the six-degrees-of-freedom movement of a robotic couch. The SDI approach to movements rotating around a predefined isocenter, referred to as a GeoIso, instead of a mechanical pivot point was developed by the robot automation industry. With robotic couch-sag corrections for weight load in a traditional SDI approach, movements could be accurately executed for a GeoIso located within a 500 mm cubic volume on the couch for treatments. The accuracy of SDI movement was investigated using the OTPS. The GeoIso was assumed to align with the proton beam isocenter (RadIso) for gantry at the reference angle. However, the misalignment between GeoIso and RadIso was quantitatively investigated by measuring the displacements at various couch angles for a target placed at the RadIso at an initial couch angle. When circular target displacements occur on a plane, a relative isocenter shift (RIS) correction could be applied in the SDI movement to minimize target displacements. Target displacements at a fixed gantry angle without and with RIS correction were measured for 12 robotic couches. Target displacements for various gantry angles were performed on three couches in gantry rooms to study the gantry-induced RadIso shift. The RIS correction can also be applied for the RadIso shift. A new SDI approach incorporating the RIS correction with the couch sag is described in this study. In parallel, the accuracy of SDI translation movements for various weight loads of patients on the couch was investigated during positioning of patients for proton prostate treatments. For a fixed gantry angle, measured target displacements without RIS correction for couch rotations in the horizontal plane varied from 4 to 20 mm. However, measured displacements perpendicular to couch rotation plane were about 2 mm for all couches. Extracted misalignments of GeoIso and RadIso in

  3. A deterministic electron, photon, proton and heavy ion transport suite for the study of the Jovian moon Europa

    International Nuclear Information System (INIS)

    Badavi, Francis F.; Blattnig, Steve R.; Atwell, William; Nealy, John E.; Norman, Ryan B.

    2011-01-01

    A Langley research center (LaRC) developed deterministic suite of radiation transport codes describing the propagation of electron, photon, proton and heavy ion in condensed media is used to simulate the exposure from the spectral distribution of the aforementioned particles in the Jovian radiation environment. Based on the measurements by the Galileo probe (1995-2003) heavy ion counter (HIC), the choice of trapped heavy ions is limited to carbon, oxygen and sulfur (COS). The deterministic particle transport suite consists of a coupled electron photon algorithm (CEPTRN) and a coupled light heavy ion algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means to the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, photon, proton and heavy ion exposure assessment in a complex space structure. In this paper, the reference radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron and proton spectra of the Jovian environment as generated by the jet propulsion laboratory (JPL) Galileo interim radiation electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter system mission (EJSM), the JPL provided Europa mission fluence spectrum, is used to produce the corresponding depth dose curve in silicon behind a default aluminum shield of 100 mils (∼0.7 g/cm 2 ). The transport suite can also accept a geometry describing ray traced thickness file from a computer aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point within the interior of the vehicle. In that regard, using a low fidelity CAD model of the Galileo probe generated by the authors, the transport suite was verified versus Monte Carlo (MC) simulation for orbits JOI-J35 of the Galileo probe

  4. Spatial distribution function of electron-photon shower particles for different values of Esub(0)/. beta. in isothermal atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Ivanenko, I P; Osipova, L N; Roganova, T M; Fedorova, G F [Moskovskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki

    1982-12-01

    Results of calculations of the spatial distribution function (SDF) of electron-photon shower particles for different values of the parameter E/sub 0//..beta.. in an isothermal atmosphere are given. Consideration of finiteness of the parameter E/sub 0//..beta.. leads to narrowing of SDF two times at E/sub 0//..beta.. approximately 10-100 as compared with the Nishimura, Kamata, Greisen SDF (E/sub 0//..beta.. = infinity). Atmosphere inhomogeneity results in SDF broadening in comparison with SDFsub(hom) (E/sub 0//..beta..) calculated for homogeneous atmosphere. SDFsub(inhom) (E/sub 0//..beta..) and SDFsub(hom) (E/sub 0//..beta..) depend on E/sub 0//..beta.. differently which is attributed to different contributions of shower prehistory to SDF formation. The larger is E/sub 0//..beta.., the wider is cascade curve and the higher is the effect of shower prehistory.

  5. Monte Carlo benchmark calculations of energy deposition by electron/photon showers up to 1 GeV

    International Nuclear Information System (INIS)

    Mehlhorn, T.A.; Halbleib, J.A.

    1983-01-01

    Over the past several years the TIGER series of coupled electron/photon Monte Carlo transport codes has been applied to a variety of problems involving nuclear and space radiations, electron accelerators, and radioactive sources. In particular, they have been used at Sandia to simulate the interaction of electron beams, generated by pulsed-power accelerators, with various target materials for weapons effect simulation, and electron beam fusion. These codes are based on the ETRAN system which was developed for an energy range from about 10 keV up to a few tens of MeV. In this paper we will discuss the modifications that were made to the TIGER series of codes in order to extend their applicability to energies of interest to the high energy physics community (up to 1 GeV). We report the results of a series of benchmark calculations of the energy deposition by high energy electron beams in various materials using the modified codes. These results are then compared with the published results of various experimental measurements and other computational models

  6. Electron-photon angular correlation measurements for excitation of the 2P state of hydrogen at 55 and 100 eV

    International Nuclear Information System (INIS)

    Slevin, J.; Eminyan, M.; Woolsey, J.M.; Vassilev, G.; Porter, H.Q.

    1980-01-01

    Electron-photon angular correlations have been measured for excitation of the 2P state of hydrogen at incident energies of 55 and 100 eV. The data presented extend the results of Weigold and co-workers (Flinders Univ. preprint (1980)) to smaller scattering angles and reveal the existence of a deep minimum in the parameter lambda thetasub(e) = 10 0 at and incident electron energy of 100 eV. (author)

  7. Liquid argon as an electron/photon detector in the energy range of 50 MeV to 2 GeV: a Monte Carlo investigation

    International Nuclear Information System (INIS)

    Goodman, M.S.; Denis, G.; Hall, M.; Karpovsky, A.; Wilson, R.; Gabriel, T.A.; Bishop, B.L.

    1980-12-01

    Monte Carlo techniques which have been used to study the characteristics of a proposed electron/photon detector based on the total absorption of electromagnetic showers in liquid argon have been investigated. The energy range studied was 50 MeV to 2 GeV. Results are presented on the energy and angular resolution predicted for the device, along with the detailed predictions of the transverse and longitudinal shower distributions. Comparisons are made with other photon detectors, and possible applications are discussed

  8. Monte Carlo electron-photon transport using GPUs as an accelerator: Results for a water-aluminum-water phantom

    Energy Technology Data Exchange (ETDEWEB)

    Su, L.; Du, X.; Liu, T.; Xu, X. G. [Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2013-07-01

    An electron-photon coupled Monte Carlo code ARCHER - Accelerated Radiation-transport Computations in Heterogeneous Environments - is being developed at Rensselaer Polytechnic Institute as a software test bed for emerging heterogeneous high performance computers that utilize accelerators such as GPUs. In this paper, the preliminary results of code development and testing are presented. The electron transport in media was modeled using the class-II condensed history method. The electron energy considered ranges from a few hundred keV to 30 MeV. Moller scattering and bremsstrahlung processes above a preset energy were explicitly modeled. Energy loss below that threshold was accounted for using the Continuously Slowing Down Approximation (CSDA). Photon transport was dealt with using the delta tracking method. Photoelectric effect, Compton scattering and pair production were modeled. Voxelised geometry was supported. A serial ARHCHER-CPU was first written in C++. The code was then ported to the GPU platform using CUDA C. The hardware involved a desktop PC with an Intel Xeon X5660 CPU and six NVIDIA Tesla M2090 GPUs. ARHCHER was tested for a case of 20 MeV electron beam incident perpendicularly on a water-aluminum-water phantom. The depth and lateral dose profiles were found to agree with results obtained from well tested MC codes. Using six GPU cards, 6x10{sup 6} histories of electrons were simulated within 2 seconds. In comparison, the same case running the EGSnrc and MCNPX codes required 1645 seconds and 9213 seconds, respectively, on a CPU with a single core used. (authors)

  9. 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

  10. OS03.4 Gammaknife versus Linac based (EDGE) radiosurgery (SRS) for patients with limited brain metastases (BMS) from different solid tumor: a phase III randomized trial.

    Science.gov (United States)

    Scorsetti, M.; Navarria, P.; Ascolese, A.; Clerici, E.; Mancosu, P.; Picozzi, P.; Pecchioli, G.; Franzese, C.; Reggiori, G.; Tomatis, S.

    2017-01-01

    Abstract Introduction: Radiosurgery is an emerging terapeutich approach for the treatment of brain metastases (BMs), considering the effective local control obtained without neurological impairment. Different technological modalities have been used: Gammaknife, Cybernife, or Linac with comparable results and different incidence of symptomatic radionecrosis. To date no comparative randomized studies have been published on this matter. We draw this randomized phase III trial with the aim to evaluate incidence of symptomatic radionecrosis using gamma knife radiosurgery versus linac based (EDGE) radiosurgery. Local control (LC) rate and patients overall survival (OS) were assessed as well. Materials: Patients with limited BMs (up to 4) from different solid tumors, except SCLC or hematologic malignancies, were enrolled. Inclusion criteria were a histopatological diagnosis of malignant primary tumor, a KPS ≥70, RPA class I-II, and BMs with maximum diameter ≤3 cm and/or with a total tumor volume <30 cm3. The total dose prescribed was 24 Gy for BMs ≤ 20 mm or 4.2 cm3, and 20 Gy for BMs 21–30 mm or volume <14.1 cm3 as suggested by RTOG guidelines. Clinical outcome was evaluated by neurological examination and MRI at 2 months after SRS and then every 3 months. The radionecrosis was considered the presence of central hypodensity and peripheral enhancement on T1-weighted post-contrast imaging, with edema on T2-weighted sequences and a clear lack of perfusion without any nodular highly vascularized area within the contrast enhanced lesion on perfusion MRI. Local progression was defined as radiographic increase of the enhancing abnormality in the irradiated volume on serial MR imaging, and distant failure by the presence of new brain metastases or leptomeningeal enhancement outside the irradiated volume. Results: From October 2014 to December 2015, 101 consecutives patients of the expected 250, for 167 BMs treated, were evaluated. The most common primary

  11. Measurement of cone beam CT coincidence with megavoltage isocentre and image sharpness using the QUASAR(TM) Penta-Guide phantom

    International Nuclear Information System (INIS)

    Sykes, J R; Lindsay, R; Dean, C J; Thwaites, D I; Brettle, D S; Magee, D R

    2008-01-01

    For image-guided radiotherapy (IGRT) systems based on cone beam CT (CBCT) integrated into a linear accelerator, the reproducible alignment of imager to x-ray source is critical to the registration of both the x-ray-volumetric image with the megavoltage (MV) beam isocentre and image sharpness. An enhanced method of determining the CBCT to MV isocentre alignment using the QUASAR(TM) Penta-Guide phantom was developed which improved both precision and accuracy. This was benchmarked against our existing method which used software and a ball-bearing (BB) phantom provided by Elekta. Additionally, a method of measuring an image sharpness metric (MTF 50 ) from the edge response function of a spherical air cavity within the Penta-Guide phantom was developed and its sensitivity was tested by simulating misalignments of the kV imager. Reproducibility testing of the enhanced Penta-Guide method demonstrated a systematic error of 50 for five measurements was 0.278 ± 0.004 lp mm -1 with no applied misalignment. Simulated misalignments exhibited a clear peak in the MTF 50 enabling misalignments greater than 0.4 mm to be detected. The Penta-Guide phantom can be used to precisely measure CBCT-MV coincidence and image sharpness on CBCT-IGRT systems

  12. Dose gradient analyses in linac-based intracranial stereotactic radiosurgery using paddick's gradient index. Consideration of the optimal method for plan evaluation

    International Nuclear Information System (INIS)

    Ohtakara, Kazuhiro; Hayashi, Shinya; Hoshi, Hiroaki

    2011-01-01

    The objective of our study was to describe the dose gradient characteristics of Linac-based stereotactic radiosurgery using Paddick's gradient index (GI) and to elucidate the factors influencing the GI value. Seventy-three plans for brain metastases using the dynamic conformal arcs were reviewed. The GI values were calculated at the 80% and 90% isodose surfaces (IDSs) and at the different target coverage IDSs (D99, D95, D90, and D85). The GI values significantly decreased as the target coverage of the reference IDS increased (the percentage of the IDS decreased). There was a significant inverse correlation between the GI values and target volume. The plans generated with the addition of a 1-mm leaf margin had worse GI values both at the D99 and D95 relative to those without leaf margin. The number and arrangement of arcs also affected the GI value. The GI values are highly sensitive to the IDS selection variability for dose prescription or evaluation, the target volume, and the planning method. To objectively compare the quality of dose gradient between rival plans, it would be preferable to employ the GI defined at the reference IDS indicating the specific target coverage (exempli gratia (e.g.), D95), irrespective of the intended marginal dose. The modified GI (mGI), defined in this study, substituting the denominator of the original GI with the target volume, would be useful to compensate for the false superior GI value in cases of target over-coverage with the reference IDS and to objectively evaluate the dose gradient outside the target boundary. (author)

  13. TU-H-BRA-08: The Design and Characteristics of a Novel Compact Linac-Based MRI Guided Radiation Therapy (MR-IGRT) System

    International Nuclear Information System (INIS)

    Mutic, S; Low, D; Chmielewski, T; Fought, G; Hernandez, M; Kawrakow, I; Sharma, A; Shvartsman, S; Dempsey, J

    2016-01-01

    Purpose: To describe the design and characteristics of a novel linac-based MRI guided radiation therapy system that addresses RF and magnetic field interference and that can be housed in conventional radiotherapy vaults. Methods: The MR-IGRT system will provide simultaneous MR imaging combined with both simple (3D) and complex (IMRT, SBRT, SRS) techniques. The system is a combination of a) double-donut split solenoidal superconducting 0.345T MRI; and b) a 90 cm isocenter ring-gantry mounted 6MV, flattening filter-free linac coupled with a stacked doubly-focused multileaf collimator with 4 mm resolution. A novel RF shielding and absorption technology was developed to isolate the beam generating RF emissions from the MR, while a novel magnetic shielding sleeve system was developed to place the magnetic field-sensitive components in low-magnetic field regions. The system design produces high spatial resolution radiation beams with state-of-the art radiation dose characteristics and simultaneous MR imaging. Results: Prototype testing with a spectrum analyzer has demonstrated complete elimination of linac RF inside the treatment room. The magnetic field inside of the magnetic shielding was well below the specification, allowing the linear accelerator to operate normally. A novel on-gantry shimming system maintained < 25 ppm magnetic field homogeneity over a 45 cm spherical field of view for all gantry angles. Conclusion: The system design demonstrates the feasibility coupling a state-of-the art linac system with a 0.345T MRI, enabling highly conformal radiation therapy with simultaneous MR image guidance. S. Mutic’s employer (Washington University) has grant with ViewRay; D. Low is former ViewRay scientific advisory board member (ended October 2015); T. Chmielewski, G. Fought, M. Hernandez, I. Kawrakow, A. Sharma, S. Shvartsman, J. Dempsey are employees of ViewRay with stock options (Dempsey has leadership role and Dempsey/Kawrakow have stock).

  14. Poster - 44: Development and implementation of a comprehensive end-to-end testing methodology for linac-based frameless SRS QA using a modified commercial stereotactic anthropomorphic phantom

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Derek; Mutanga, Theodore [University of Toronto, Carlo Fidani Peel Regional Cancer Center (Canada)

    2016-08-15

    Purpose: An end-to-end testing methodology was designed to evaluate the overall SRS treatment fidelity, incorporating all steps in the linac-based frameless radiosurgery treatment delivery process. The study details our commissioning experience of the Steev (CIRS, Norfolk, VA) stereotactic anthropomorphic head phantom including modification, test design, and baseline measurements. Methods: Repeated MR and CT scans were performed with interchanging inserts. MR-CT fusion accuracy was evaluated and the insert spatial coincidence was verified on CT. Five non-coplanar arcs delivered a prescription dose to a 15 mm spherical CTV with 2 mm PTV margin. Following setup, CBCT-based shifts were applied as per protocol. Sequential measurements were performed by interchanging inserts without disturbing the setup. Spatial and dosimetric accuracy was assessed by a combination of CBCT hidden target, radiochromic film, and ion chamber measurements. To facilitate film registration, the film insert was modified in-house by etching marks. Results: MR fusion error and insert spatial coincidences were within 0.3 mm. Both CBCT and film measurements showed spatial displacements of 1.0 mm in similar directions. Both coronal and sagittal films reported 2.3 % higher target dose relative to the treatment plan. The corrected ion chamber measurement was similarly greater by 1.0 %. The 3 %/2 mm gamma pass rate was 99% for both films Conclusions: A comprehensive end-to-end testing methodology was implemented for our SRS QA program. The Steev phantom enabled realistic evaluation of the entire treatment process. Overall spatial and dosimetric accuracy of the delivery were 1 mm and 3 % respectively.

  15. TU-H-BRA-08: The Design and Characteristics of a Novel Compact Linac-Based MRI Guided Radiation Therapy (MR-IGRT) System

    Energy Technology Data Exchange (ETDEWEB)

    Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States); Low, D [UCLA, Los Angeles, CA (United States); Chmielewski, T; Fought, G; Hernandez, M; Kawrakow, I; Sharma, A; Shvartsman, S; Dempsey, J [ViewRay, Inc., Oakwood Village, OH (United States)

    2016-06-15

    Purpose: To describe the design and characteristics of a novel linac-based MRI guided radiation therapy system that addresses RF and magnetic field interference and that can be housed in conventional radiotherapy vaults. Methods: The MR-IGRT system will provide simultaneous MR imaging combined with both simple (3D) and complex (IMRT, SBRT, SRS) techniques. The system is a combination of a) double-donut split solenoidal superconducting 0.345T MRI; and b) a 90 cm isocenter ring-gantry mounted 6MV, flattening filter-free linac coupled with a stacked doubly-focused multileaf collimator with 4 mm resolution. A novel RF shielding and absorption technology was developed to isolate the beam generating RF emissions from the MR, while a novel magnetic shielding sleeve system was developed to place the magnetic field-sensitive components in low-magnetic field regions. The system design produces high spatial resolution radiation beams with state-of-the art radiation dose characteristics and simultaneous MR imaging. Results: Prototype testing with a spectrum analyzer has demonstrated complete elimination of linac RF inside the treatment room. The magnetic field inside of the magnetic shielding was well below the specification, allowing the linear accelerator to operate normally. A novel on-gantry shimming system maintained < 25 ppm magnetic field homogeneity over a 45 cm spherical field of view for all gantry angles. Conclusion: The system design demonstrates the feasibility coupling a state-of-the art linac system with a 0.345T MRI, enabling highly conformal radiation therapy with simultaneous MR image guidance. S. Mutic’s employer (Washington University) has grant with ViewRay; D. Low is former ViewRay scientific advisory board member (ended October 2015); T. Chmielewski, G. Fought, M. Hernandez, I. Kawrakow, A. Sharma, S. Shvartsman, J. Dempsey are employees of ViewRay with stock options (Dempsey has leadership role and Dempsey/Kawrakow have stock).

  16. A Deterministic Electron, Photon, Proton and Heavy Ion Radiation Transport Suite for the Study of the Jovian System

    Science.gov (United States)

    Norman, Ryan B.; Badavi, Francis F.; Blattnig, Steve R.; Atwell, William

    2011-01-01

    A deterministic suite of radiation transport codes, developed at NASA Langley Research Center (LaRC), which describe the transport of electrons, photons, protons, and heavy ions in condensed media is used to simulate exposures from spectral distributions typical of electrons, protons and carbon-oxygen-sulfur (C-O-S) trapped heavy ions in the Jovian radiation environment. The particle transport suite consists of a coupled electron and photon deterministic transport algorithm (CEPTRN) and a coupled light particle and heavy ion deterministic transport algorithm (HZETRN). The primary purpose for the development of the transport suite is to provide a means for the spacecraft design community to rapidly perform numerous repetitive calculations essential for electron, proton and heavy ion radiation exposure assessments in complex space structures. In this paper, the radiation environment of the Galilean satellite Europa is used as a representative boundary condition to show the capabilities of the transport suite. While the transport suite can directly access the output electron spectra of the Jovian environment as generated by the Jet Propulsion Laboratory (JPL) Galileo Interim Radiation Electron (GIRE) model of 2003; for the sake of relevance to the upcoming Europa Jupiter System Mission (EJSM), the 105 days at Europa mission fluence energy spectra provided by JPL is used to produce the corresponding dose-depth curve in silicon behind an aluminum shield of 100 mils ( 0.7 g/sq cm). The transport suite can also accept ray-traced thickness files from a computer-aided design (CAD) package and calculate the total ionizing dose (TID) at a specific target point. In that regard, using a low-fidelity CAD model of the Galileo probe, the transport suite was verified by comparing with Monte Carlo (MC) simulations for orbits JOI--J35 of the Galileo extended mission (1996-2001). For the upcoming EJSM mission with a potential launch date of 2020, the transport suite is used to compute

  17. SU-F-T-615: Comparison of Plan Quality for Linac-Based Stereotactic Radiosurgery (SRS) Using Single- and Multi-Isocenter Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chang, J [Dept of Radiation Medicine, Northwell Health, Lake Success, NY (United States); Dept of Radiation Oncology, NewYork Hospital/Weill Cornell Medical College, New York, NY (United States); Wernicke, A [Dept of Radiation Oncology, NewYork Hospital/Weill Cornell Medical College, New York, NY (United States); Pannullo, S [Dept of Neurological Surgery, NewYork Hospital/Weill Cornell Medical College, New York, NY (United States)

    2016-06-15

    Purpose: To compare the plan quality of linear accelerator (linac)-based stereotactic radiosurgery (SRS) using single-isocenter volumetric arc therapy (SI-VMAT), restricted single-isocenter dynamic-arc (RSI-DARC), and multi-isocenter DARC (MI-DARC) techniques. Methods: Fifteen SRS cases were randomly selected and re-planned using the SI-VMAT (Pinnacle), RSI-DARC (iPlanNet) and MI-DARC (iPlanNet). The number of planning target volumes (PTVs) for each plan ranged from 1 to 6. For SI-VMAT, a single isocenter and 3-4 VMAT beams are used for all PTVs, while for MI-DARC, each PTV has its own isocetner with 3 DARC beams. RSI-DARC uses one isocnter with 3-6 DARC beams to irradiate all PTVs within 2.5-cm radius. Both SI-DARC and RSI-DARC plans were optimized manually. The prescription dose was 20 Gy to each PTV. The maximal dose was 25 Gy for RSI-DARC and MI-DARC, but could not be controlled for SI-VMAT due to the nature of VMAT planning. Plan quality indexes including PTV coverage, mean dose of PTV (PTVmean) and tissue (Tmean), V12Gy, conformity index (CI), and V10Gy/VPTV were calculated and compared. Results: Full PTV coverage was achieved for all three techniques. Using the MI-DARC plans as the gold standard, the PTVmean of the SI-VMAT plans was 12.5%±8.3% (mean±standard deviation) higher, in comparison to 0.7%±1.4% for the RSI-DARC plans. Similar trend was observed for other indexes including V12Gy (39.4%±27.3% vs. 9.3%±7.8%), Tmean (35.0%±26.8% vs. 2.8%±3.4%), and V10Gy/VPTV (42.2%±31.5% vs. 9.9%±8.2%). CI is comparable (6.2%±14.2% vs. 6.3%±7.2%). Assuming the treatment time is proportional to the number of isocenters, the reduction of the treatment time in comparison to MI-DARC was 70% for SI-VMAT and 42% for RSI-DARC. Conclusion: Although the SI-VMAT can save a considerable amount of treatment time, the plan indexes also significantly deviates from the gold standard, MI-DARC. RSI-DARC, on the other hand, provides a good compromise between the treatment

  18. SU-F-T-611: Critical Analysis and Efficacy of Linac Based (Beam Modulator) and Cyberknife Treatment Plans for Acoustic Neuroma/schwannoma

    International Nuclear Information System (INIS)

    KP, Karrthick; Kataria, T; Thiyagarajan, R; Selvan, T; Abhishek, A

    2016-01-01

    Purpose: To study the critical analysis and efficacy of Linac and Cyberknife (CK) treatment plans for acoustic neuroma/schwannoma. Methods: Twelve of acoustic neuroma/schwannoma patients were taken for these study that. Treatment plans were generated in Multiplan treatment planning system (TPS) for CK using 5,7.5 and 10mm diameter collimators. Target volumes were in the range of 0.280 cc to 9.256 cc. Prescription dose (Rx) ranges from 1150cGy to 1950cGy delivered over 1 to 3 Fractions. For same patients stereotactic Volumetric modulated arc plans were generated using Elekta Linac with MLC thickness of 4mm in Monaco TPS. Appropriate calculation algorithms and grid size were used with same Rx and organ at risk (OAR) constrains for both Linac and CK plans. Treatment plans were developed to achieve at least 95% of the target volume to receive the Rx. The dosimetric indices such as conformity index (CI), coverage, OAR dose and volume receiving 50% of Rx (V50%) were used to evaluate the plans. Results: Target volumes ranges from 0.280 cc to 3.5cc shows the CI of 1.16±0.109 and 1.53±0.360 for cyberknife and Linac plans respectively. For small volume targets, the OARs were well spared in CK plans. There are no significant differences in CI and OAR doses were observed between CK and Linac plans that have the target volume >3.5 cc. Perhaps the V50% were lesser in CK plans, and found to be 12.8± 8.4 and 22.8 ± 15.0 for CK and Linac respectively. Conclusion: The analysis shows the importance of collimator size for small volume targets. The target volumes >3.5 cc can be treated in Linac as comparable with CK. For targets <3.5cc CK plans showed superior plan quality with better CI and OAR sparing than the Linac based plans. Further studies may require evaluating the clinical advantage of CK robotic system.

  19. Importance of point-by-point back projection correction for isocentric motion in digital breast tomosynthesis: Relevance to morphology of structures such as microcalcifications

    International Nuclear Information System (INIS)

    Chen Ying; Lo, Joseph Y.; Dobbins, James T. III

    2007-01-01

    Digital breast tomosynthesis is a three-dimensional imaging technique that provides an arbitrary set of reconstruction planes in the breast from a limited-angle series of projection images acquired while the x-ray tube moves. Traditional shift-and-add (SAA) tomosynthesis reconstruction is a common mathematical method to line up each projection image based on its shifting amount to generate reconstruction slices. With parallel-path geometry of tube motion, the path of the tube lies in a plane parallel to the plane of the detector. The traditional SAA algorithm gives shift amounts for each projection image calculated only along the direction of x-ray tube movement. However, with the partial isocentric motion of the x-ray tube in breast tomosynthesis, small objects such as microcalcifications appear blurred (for instance, about 1-4 pixels in blur for a microcalcification in a human breast) in traditional SAA images in the direction perpendicular to the direction of tube motion. Some digital breast tomosynthesis algorithms reported in the literature utilize a traditional one-dimensional SAA method that is not wholly suitable for isocentric motion. In this paper, a point-by-point back projection (BP) method is described and compared with traditional SAA for the important clinical task of evaluating morphology of small objects such as microcalcifications. Impulse responses at different three-dimensional locations with five different combinations of imaging acquisition parameters were investigated. Reconstruction images of microcalcifications in a human subject were also evaluated. Results showed that with traditional SAA and 45 deg. view angle of tube movement with respect to the detector, at the same height above the detector, the in-plane blur artifacts were obvious for objects farther away from x-ray source. In a human subject, the appearance of calcifications was blurred in the direction orthogonal to the tube motion with traditional SAA. With point-by-point BP, the

  20. Thermally controlled coupling of a rolled-up microtube integrated with a waveguide on a silicon electronic-photonic integrated circuit.

    Science.gov (United States)

    Zhong, Qiuhang; Tian, Zhaobing; Veerasubramanian, Venkat; Dastjerdi, M Hadi Tavakoli; Mi, Zetian; Plant, David V

    2014-05-01

    We report on the first experimental demonstration of the thermal control of coupling strength between a rolled-up microtube and a waveguide on a silicon electronic-photonic integrated circuit. The microtubes are fabricated by selectively releasing a coherently strained GaAs/InGaAs heterostructure bilayer. The fabricated microtubes are then integrated with silicon waveguides using an abruptly tapered fiber probe. By tuning the gap between the microtube and the waveguide using localized heaters, the microtube-waveguide evanescent coupling is effectively controlled. With heating, the extinction ratio of a microtube whispering-gallery mode changes over an 18 dB range, while the resonant wavelength remains approximately unchanged. Utilizing this dynamic thermal tuning effect, we realize coupling modulation of the microtube integrated with the silicon waveguide at 2 kHz with a heater voltage swing of 0-6 V.

  1. Combined electron/photon (E/P) postoperative radiotherapy (RT) for early breast cancer based on central lung distance (CLD) values

    International Nuclear Information System (INIS)

    Akahane, Keiko; Takahashi, Satoshi; Nakamura, Michiko

    2008-01-01

    Combined electron/photon (E/P) method has been introduced since 1999 in the postoperative radiotherapy (RT) for 27 early breast cancer patients out of 491, whose central lung disease (CLD) exceeded over 2.5 cm. Several parameters were analyzed between the conventional method and E/P method. Remarkable improvement was established as follows, CLD 2.64 vs. 1.26 cm, maximum lung distance (MLD) 2.75 vs. 1.40 cm and maximum heart distance (MHD) 1.81 vs. 0.58 cm, respectively (p<0.0001). Combined E/P method would be valid to avoid lung complications and long-term cardiac mortality. (author)

  2. On a spatial distribution function of electron-photon shower particles for different values of Esub(0)/#betta# in isothermal atmosphere

    International Nuclear Information System (INIS)

    Ivanenko, I.P.; Osipova, L.N.; Roganova, T.M.; Fedorova, G.F.

    1982-01-01

    Results of calculations of scape distribution function (SDF) of electron-photon shower particles for different values of a parameter E 0 /#betta# in isothermal atmosphere are given. Consideration of finiteness of the parameter E 0 /#betta# leads to narrowing of SDF two times at E 0 /#betta# approximately 10-100 as compared with the Nishimura, Kamata, Greisen SDF (E 0 /#betta# = infinity). Atmosphere inhomogeneity results in SDF broadening in comparison with SDFsub(hom) (E 0 /#betta#) calculated for homogeneous atmosphere. SDFsub(inhom) (E 0 /#betta#) and SDFsub(hom) (E 0 /#betta#) depend on E 0 /#betta# differently which is attributed to different contributions of shower prehistory to SDF formation. The larger is E 0 /#betta# the wider is cascade curve and the higher is the effect of shower prehistory

  3. Low-energy measurements of electron-photon angular correlation in electron-impact excitation of the 21P state of helium

    International Nuclear Information System (INIS)

    Steph, N.C.; Golden, D.E.

    1983-01-01

    Electron-photon angular correlations between electrons which have excited the 2 1 P state of He and photons from the 2 1 P→1 1 S transition have been studied for 27-, 30-, 35-, and 40-eV incident electrons. Values of lambda and Vertical BarchiVertical Bar obtained from these measurements are compared to values obtained in distorted-wave and R-matrix calculations. The values of lambda and Vertical BarchiVertical Bar have been combined to examine the behavior of Vertical BarO 1 /sub -//sup colvertical-bar/ [lambda(1-lambda)sinVertical BarchiVertical Bar], the nonvanishing component of orientation. At 27 eV, a substantial decrease was observed in the values of lambda and Vertical BarO 1 /sub -//sup colvertical-bar/, compared with their values for E> or =30 eV

  4. ITS version 5.0 :the integrated TIGER series of coupled electron/Photon monte carlo transport codes with CAD geometry.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

    2005-09-01

    ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2) multigroup codes with adjoint transport capabilities, (3) parallel implementations of all ITS codes, (4) a general purpose geometry engine for linking with CAD or other geometry formats, and (5) the Cholla facet geometry library. Moreover, the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.

  5. Electron-photon angular correlation measurements of He (1 1S0-2 1P1) excitation by electron impact at 80 eV

    International Nuclear Information System (INIS)

    Steph, N.C.; Golden, D.E.

    1980-01-01

    The electron-photon angular correlation function was measured between 80-eV electrons which excited the 2 1 P 1 state of helium and 58.4-nm photons from the decay of that state for electron scattering angles ranging from 5 0 to 100 0 . The data have been analyzed to yield values of the ratio lambda of the differential cross section for exciting the M/sub j/=0 sublevel to the total differential cross section and the magnitude vertical-barchivertical-bar of the phase difference between the M/sub j/=0 and M/sub j/=1 excitation amplitudes. The data agree with all previous measurements within one standard deviation, with the exception of the large-angle values of lambda obtained by Hollywood, Crowe, and Williams. Possible causes of these discrepancies are discussed. The values of lambda and vertical-barchivertical-bar obtained in this work agree quite well with those given by the distorted-wave calculations of Madison over the entire angular range

  6. Volume CT with a flat-panel detector on a mobile, isocentric C-arm: Pre-clinical investigation in guidance of minimally invasive surgery

    International Nuclear Information System (INIS)

    Siewerdsen, J.H.; Moseley, D.J.; Burch, S.; Bisland, S.K.; Bogaards, A.; Wilson, B.C.; Jaffray, D.A.

    2005-01-01

    A mobile isocentric C-arm (Siemens PowerMobil) has been modified in our laboratory to include a large area flat-panel detector (in place of the x-ray image intensifier), providing multi-mode fluoroscopy and cone-beam computed tomography (CT) imaging capability. This platform represents a promising technology for minimally invasive, image-guided surgical procedures where precision in the placement of interventional tools with respect to bony and soft-tissue structures is critical. The image quality and performance in surgical guidance was investigated in pre-clinical evaluation in image-guided spinal surgery. The control, acquisition, and reconstruction system are described. The reproducibility of geometric calibration, essential to achieving high three-dimensional (3D) image quality, is tested over extended time scales (7 months) and across a broad range in C-arm angulation (up to 45 deg.), quantifying the effect of improper calibration on spatial resolution, soft-tissue visibility, and image artifacts. Phantom studies were performed to investigate the precision of 3D localization (viz., fiber optic probes within a vertebral body) and effect of lateral projection truncation (limited field of view) on soft-tissue detectability in image reconstructions. Pre-clinical investigation was undertaken in a specific spinal procedure (photodynamic therapy of spinal metastases) in five animal subjects (pigs). In each procedure, placement of fiber optic catheters in two vertebrae (L1 and L2) was guided by fluoroscopy and cone-beam CT. Experience across five procedures is reported, focusing on 3D image quality, the effects of respiratory motion, limited field of view, reconstruction filter, and imaging dose. Overall, the intraoperative cone-beam CT images were sufficient for guidance of needles and catheters with respect to bony anatomy and improved surgical performance and confidence through 3D visualization and verification of transpedicular trajectories and tool placement

  7. Polymers for electronic & photonic application

    CERN Document Server

    Wong, C P

    2013-01-01

    The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be info

  8. Investigation of ionization losses of shower electrons in electron-photon shower developed in liquid xenon by gamma quanta in the energy range 1600-3400 MeV

    International Nuclear Information System (INIS)

    Okhrymenko, L.S.; Slowinski, B.; Strugalski, Z.; Sredniawa, B.

    1975-01-01

    Results of the investigation of differential distributions of ionization losses and the corresponding fluctuations for shower electrons in the longitudinal development of electron-photon showers produced by gamma-quanta of energies Esub(γ)=1600-3400 MeV in liquid xenon are given. A simple and convenient from the methodical point of view two-parametric function, approximating the observed distribution has been obtained. The independence of the fluctuations of ionization losses of shower electrons on the energy of gamma-quanta in the investigated interval of Esub(γ) values has been found

  9. Measurement of neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photon induced reaction on natC using laser electron photon beam at NewSUBARU

    Science.gov (United States)

    Itoga, Toshiro; Nakashima, Hiroshi; Sanami, Toshiya; Namito, Yoshihito; Kirihara, Yoichi; Miyamoto, Shuji; Takemoto, Akinori; Yamaguchi, Masashi; Asano, Yoshihiro

    2017-09-01

    Photo-neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photons on natC were measured using laser Compton scattering facility at NewSUBARU BL01. The photon energy spectra were evaluated through measurements and simulations with collimator sizes and arrangements for the laser electron photon. The neutron energy spectra for the natC(g,xn) reaction were measured at 60 degrees in horizontal and 90 degrees in horizontal and vertical with respect to incident photon. The spectra show almost isotropic angular distribution and flat energy distribution from detection threshold to upper limit defined by reaction Q-value.

  10. Measurement of neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photon induced reaction on natC using laser electron photon beam at NewSUBARU

    Directory of Open Access Journals (Sweden)

    Itoga Toshiro

    2017-01-01

    Full Text Available Photo-neutron energy spectra for Eg=23.1 and 26.6 MeV mono-energetic photons on natC were measured using laser Compton scattering facility at NewSUBARU BL01. The photon energy spectra were evaluated through measurements and simulations with collimator sizes and arrangements for the laser electron photon. The neutron energy spectra for the natC(g,xn reaction were measured at 60 degrees in horizontal and 90 degrees in horizontal and vertical with respect to incident photon. The spectra show almost isotropic angular distribution and flat energy distribution from detection threshold to upper limit defined by reaction Q-value.

  11. MO-FG-CAMPUS-TeP1-04: Pseudo-In-Vivo Dose Verification of a New Mono-Isocentric Technique for the Treatment of Multiple Brain Metastases

    International Nuclear Information System (INIS)

    Pappas, E P; Makris, D; Lahanas, V; Papanikolaou, N; Watts, L; Kalaitzakis, G; Boursianis, T; Maris, T; Genitsarios, I; Pappas, E; Stathakis, S

    2016-01-01

    Purpose: To validate dose calculation and delivery accuracy of a recently introduced mono-isocentric technique for the treatment of multiple brain metastases in a realistic clinical case. Methods: Anonymized CT scans of a patient were used to model a hollow phantom that duplicates anatomy of the skull. A 3D printer was used to construct the phantom of a radiologically bone-equivalent material. The hollow phantom was subsequently filled with a polymer gel 3D dosimeter which also acted as a water-equivalent material. Irradiation plan consisted of 5 targets and was identical to the one delivered to the specific patient except for the prescription dose which was optimized to match the gel dose-response characteristics. Dose delivery was performed using a single setup isocenter dynamic conformal arcs technique. Gel dose read-out was carried out by a 1.5 T MRI scanner. All steps of the corresponding patient’s treatment protocol were strictly followed providing an end-to-end quality assurance test. Pseudo-in-vivo measured 3D dose distribution and calculated one were compared in terms of spatial agreement, dose profiles, 3D gamma indices (5%/2mm, 20% dose threshold), DVHs and DVH metrics. Results: MR-identified polymerized areas and calculated high dose regions were found to agree within 1.5 mm for all targets, taking into account all sources of spatial uncertainties involved (i.e., set-up errors, MR-related geometric distortions and registration inaccuracies). Good dosimetric agreement was observed in the vast majority of the examined profiles. 3D gamma index passing rate reached 91%. DVH and corresponding metrics comparison resulted in a satisfying agreement between measured and calculated datasets within targets and selected organs-at-risk. Conclusion: A novel, pseudo-in-vivo QA test was implemented to validate spatial and dosimetric accuracy in treatment of multiple metastases. End-to-end testing demonstrated that our gel dosimetry phantom is suited for such QA

  12. MO-FG-CAMPUS-TeP1-04: Pseudo-In-Vivo Dose Verification of a New Mono-Isocentric Technique for the Treatment of Multiple Brain Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, E P; Makris, D; Lahanas, V [National and Kapodistrian University of Athens, Athens, Attiki (Greece); Papanikolaou, N; Watts, L [University of Texas HSC SA, San Antonio, TX (United States); Kalaitzakis, G; Boursianis, T; Maris, T [University of Crete, Heraklion, Crete (Greece); Genitsarios, I; Pappas, E [Technological Educational Institute Of Athens, Athens, Attiki (Greece); Stathakis, S [Cancer Therapy and Research Center, San Antonio, TX (United States)

    2016-06-15

    Purpose: To validate dose calculation and delivery accuracy of a recently introduced mono-isocentric technique for the treatment of multiple brain metastases in a realistic clinical case. Methods: Anonymized CT scans of a patient were used to model a hollow phantom that duplicates anatomy of the skull. A 3D printer was used to construct the phantom of a radiologically bone-equivalent material. The hollow phantom was subsequently filled with a polymer gel 3D dosimeter which also acted as a water-equivalent material. Irradiation plan consisted of 5 targets and was identical to the one delivered to the specific patient except for the prescription dose which was optimized to match the gel dose-response characteristics. Dose delivery was performed using a single setup isocenter dynamic conformal arcs technique. Gel dose read-out was carried out by a 1.5 T MRI scanner. All steps of the corresponding patient’s treatment protocol were strictly followed providing an end-to-end quality assurance test. Pseudo-in-vivo measured 3D dose distribution and calculated one were compared in terms of spatial agreement, dose profiles, 3D gamma indices (5%/2mm, 20% dose threshold), DVHs and DVH metrics. Results: MR-identified polymerized areas and calculated high dose regions were found to agree within 1.5 mm for all targets, taking into account all sources of spatial uncertainties involved (i.e., set-up errors, MR-related geometric distortions and registration inaccuracies). Good dosimetric agreement was observed in the vast majority of the examined profiles. 3D gamma index passing rate reached 91%. DVH and corresponding metrics comparison resulted in a satisfying agreement between measured and calculated datasets within targets and selected organs-at-risk. Conclusion: A novel, pseudo-in-vivo QA test was implemented to validate spatial and dosimetric accuracy in treatment of multiple metastases. End-to-end testing demonstrated that our gel dosimetry phantom is suited for such QA

  13. LHCb calorimeter electronics. Photon identification. Calorimeter calibration

    International Nuclear Information System (INIS)

    Machefert, F.

    2011-01-01

    LHCb is one of the four large experiments installed on the LHC accelerator ring. The aim of the detector is to precisely measure CP violation observables and rare decays in the B meson sector. The calorimeter system of LHCb is made of four sub-systems: the scintillating pad detector, the pre-shower, the electromagnetic (ECAL) and hadronic (HCAL) calorimeters. It is essential to reconstruct B decays, to efficiently trigger on interesting events and to identify electrons and photons. After a review of the LHCb detector sub-systems, the first part of this document describes the calorimeter electronics. First, the front-end electronics in charge of measuring the ECAL and HCAL signals from the photomultipliers is presented, then the following section is an overview of the control card of the four calorimeters. The chapters three and four concern the test software of this electronics and the technological choices making it tolerant to radiations in the LHCb cavern environment. The measurements performed to ensure this tolerance are also given. The second part of this document concerns both the identification of the photons with LHCb and the calibration of the calorimeters. The photon identification method is presented and the performances given. Finally, the absolute energy calibration of the PRS and ECAL, based on the data stored in 2010 is explained. (author)

  14. Computational methods of electron/photon transport

    International Nuclear Information System (INIS)

    Mack, J.M.

    1983-01-01

    A review of computational methods simulating the non-plasma transport of electrons and their attendant cascades is presented. Remarks are mainly restricted to linearized formalisms at electron energies above 1 keV. The effectiveness of various metods is discussed including moments, point-kernel, invariant imbedding, discrete-ordinates, and Monte Carlo. Future research directions and the potential impact on various aspects of science and engineering are indicated

  15. High-field electron-photon interactions

    International Nuclear Information System (INIS)

    Hartemann, F V.

    1999-01-01

    Recent advances in novel technologies (including chirped-pulse amplification, femtosecond laser systems operating in the TW-PW range, high-gradient rf photoinjectors, and synchronized relativistic electron bunches with subpicosecond durations and THz bandwidths) allow experimentalists to study the interaction of relativistic electrons with ultrahigh-intensity photon fields. Ponderomotive scattering can accelerate these electrons with extremely high gradients in a three-dimensional vacuum laser focus. The nonlinear Doppler shift induced by relativistic radiation pressure in Compton backscattering is shown to yield complex nonlinear spectra which can be modified by using temporal laser pulse shaping techniques. Colliding laser pulses, where ponderomotive acceleration and Compton backscattering are combined, could also yield extremely short wavelength photons. Finally, one expects strong radiative corrections when the Doppler-upshifted laser wavelength approaches the Compton scale. These are discussed within the context of high-field classical electrodynamics, a new discipline borne out of the aforementioned innovations

  16. Enigmatic electrons, photons, and ''empty'' waves

    International Nuclear Information System (INIS)

    MacGregor, M.H.

    1995-01-01

    A spectroscopic analysis is made of electrons and photons from the standpoint of physical realism. In this conceptual framework, moving particles are portrayed as localized entities which are surrounded by ''empty'' waves. A spectroscopic model for the electron Stands as a guide for a somewhat similar, but in essential respects radically different, model for the photon. This leads in turn to a model for the ''zeron''. the quantum of the empty wave. The properties of these quanta mandate new basis states, and hence an extension of our customary framework for dealing with them. The zeron wave field of a photon differs in one important respect from the standard formalism for an electromagnetic wave. The vacuum state emerges as more than just a passive bystander. Its polarization properties provide wave stabilization, particle probability distributions, and orbit quantization. Questions with regard to special relativity are discussed

  17. On the e-linac-based neutron yield

    International Nuclear Information System (INIS)

    Bunatyan, G.G.; Nikolenko, V.G.; Popov, A.B.

    2010-01-01

    We treat neutron generating in high atomic number materials due to the photonuclear reactions induced by the Bremsstrahlung of an electron beam produced by linear electron accelerator (e-linac). The dependence of neutron yield on the electron energy and the irradiated sample size is considered for various sample materials. The calculations are performed without resort to the so-called 'numerical Monte Carlo simulation'. The acquired neutron yields are well correlated with the data asserted in investigations performed at a number of the e-linac-driven neutron sources

  18. Development of collimator insert for linac based stereotactic irradiation

    International Nuclear Information System (INIS)

    Singh, I.R.R.; Brindha, S.; Ravindran, B.P.; Rajshekhar, V.

    1999-01-01

    The aim of this study is to develop collimator inserts of various sizes which are either not commercially available or are expensive to import. The dosimetry parameters such as tissue maximum ratio (TMR), off-axis ratio (OAR) and output factor of the developed collimator insert are compared with that of the commercial collimator insert (Radionics). In order to check the suitability of the collimator insert developed locally for clinical use and to standardize the method of development, a collimator insert of 15 mm identical to the one supplied by Radionics is developed with low-melting alloy (Cerrobend). Moreover for the clinical use of the developed collimator insert, certain acceptance tests are performed which include a collimator concentricity test, beam size check and radiation leakage test. The dose verification is carried out with a thermoluminescent dosimeter ( 7 LiF rods) and an FBX chemical dosimeter in a human-head-shaped Perspex phantom filled with water. The variation between the calculated and measured dose is found to be within +2.4% for 7 LiF rods and -2.0% for the FBX chemical dosimeter thus ensuring the suitability of the developed collimator insert for clinical use. This has encouraged us to standardize the method adapted to develop the collimator insert and to develop collimator inserts of different field sizes. (author)

  19. X-ray diffraction analysis device with electronic photon counter

    International Nuclear Information System (INIS)

    Fillit, R.Y.; Bruyas, H.; Patay, F.

    1985-01-01

    The means provided to control the movements around the three axes are composed of step-by-step motors related to exits control logic which is connected to the calculation and monitored by a clock. The clock monitors also the calculator so as that the calculator controls, together with the programmable clock and control logic, the coordination of the whole rotation movements, along the three rotation axes, their velocity, their duration and the acquisition of the measured intensities of the diffracted X-ray beam [fr

  20. The ARGUS electron/photon calorimeter. Pt. 2

    International Nuclear Information System (INIS)

    Drescher, A.; Graf, H.J.; Graewe, B.; Hofmann, W.; Markees, A.; Matthiesen, U.; Spengler, J.; Wegener, D.

    1983-03-01

    A detailed investigation is described of the photon production and transport in lead scintillator shower counters with wave-length shifter readout built for the ARGUS detector. Experimental data and Monte Carlo calculations are in good agreement. The most prominent effects due to the light collection system are small nonlinearities in the relation between deposited energy and pulse height and an energy dependent decrease of the energy resolution of the counters. (orig.)

  1. Transition radiation and coherent electron-photon scattering

    International Nuclear Information System (INIS)

    Moran, M.J.

    1985-04-01

    Relativistic electron irradiation of thin solid targets is known to generate collimated beams of x-ray photons in the forward direction by a number of different processes. A variety of mechanisms are discussed that share common characteristics in the angular and spectral distributions of the generated photon beams. Some simple physical explanations are offered for the characteristics shared by these processes. Some examples are then given based on experimental results attained at the LLNL electron-positron accelerator

  2. MEMS-Electronic-Photonic Heterogeneous Integrated FMCW Ladar Source

    Science.gov (United States)

    2015-12-18

    1   1.1.   E-­‐ PHI  PHASE  2  –  MEMS  LADAR  SOURCE...4   3.2.   PROPOSED  EO-­‐PLL   ARCHITECTURE  WITH  GATED  RAMP-­‐SWITCHING... PHI  Phase  2  –  MEMS  LADAR  Source   In  Phase  2,  we  continue  the  development  of  the  FMCW  LADAR

  3. Analysis of 125Xe electron-photon coincidence decay

    International Nuclear Information System (INIS)

    Klingberg, F.J.; Biegalski, S.R.

    2016-01-01

    As part of the verification component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), environmental gas samples originating from nuclear fission are analyzed for the presence of 131m Xe, 133m Xe, 133 Xe, and 135 Xe. In this work, the non-traditional radioxenon isotope 125 Xe was investigated. The isotope was produced as an isotopically pure sample via neutron activation of 124 Xe at the University of Texas at Austin Nuclear Engineering Teaching Lab's TRIGA MARK II Reactor. The sample was then measured using a HPGe detector as well as an ARSA-style b-c coincidence detector. Potential sources and sensitivities for production of 125 Xe are also considered for relevance to the CTBT verification mission. (author)

  4. Electron, photons, and molecules: Storing energy from light

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.R. [Argonne National Laboratory, IL (United States)

    1996-09-01

    Molecular charge separation has important potential for photochemical energy storage. Its efficiency can be enhanced by principals which maximize the rates of the electron transfer steps which separate charge and minimize those which recombine high-energy charge pairs to lose stored energy. Dramatic scientific progress in understanding these principals has occurred since the founding of DOE and its predecessor agency ERDA. While additional knowledge in needed in broad areas of molecular electron transfer, some key areas of knowledge hold particular promise for the possibility of moving this area from science toward technology capable of contributing to the nation`s energy economy.

  5. Quantum Kinetic Theory and Applications Electrons, Photons, Phonons

    CERN Document Server

    Vasko, Fedir T

    2006-01-01

    This lecture-style monograph is addressed to several categories of readers. First, it will be useful for graduate students studying theory. Second, the topics covered should be interesting for postgraduate students of various specializations. Third, the researchers who want to understand the background of modern theoretical issues in more detail can find a number of useful results here. The phenomena covered involve kinetics of electron, phonon, and photon systems in solids. The dynamical properties and interactions of electrons, phonons, and photons are briefly described in Chapter 1. Further, in Chapters 2-8, the authors present the main theoretical methods: linear response theory, various kinetic equations for the quasiparticles under consideration, and diagram technique. The presentation of the key approaches is always accompanied by solutions of concrete problems to illustrate ways to apply the theory. The remaining chapters are devoted to various manifestations of quantum transport in solids. The choice...

  6. Electrons/Photons Reconstruction with the ATLAS Detector

    CERN Document Server

    Benslama, K

    2006-01-01

    The calibration of electromagnetic clusters is one of the key issues of ATLAS (and the LHC) in 2007. The cluster alogrithm starting from electronically calibrated calorimeter cells will be described. Local position and local energy variations are corrected for. As a last step, longitudinal weights are applied to correct for energy loss upstream of the calorimeter. Strongly influenced by testbeam studies, the new longitudinal weighting optimizes simultaneously energy resolution and linearity. Methods to derive the final calibration parameters from the physics events have been developped. The electron and photon identification methods (cuts and multivariate analyses) and their performance will then be discussed.

  7. Effect of electron-photon interaction on the knight shift

    International Nuclear Information System (INIS)

    Tripathi, G.S.; Misra, C.M.; Tripathi, P.; Misra, P.K.

    1990-01-01

    The effect of electron-phonon interaction is considered on the spin (K s ), orbital (K o ) and spin-orbit (K so ) contributions to the Knight shift. In case of K s , it is found that the modifications caused due to the magnetic field dependence of electron self-energy in the presence of electron-phonon interaction is cancelled by the electron-phonon mass enhancement. However, in the presence of both electron-electron and electron-phonon interactions, the exchange enhancement parameter α is modified to α(1+γ) -1 where γ is the electron-phonon mass enhancement parameter. The orbital and spin-orbital contributions are mainly modified through the changes in the one-electron energies and wave functions. (orig.)

  8. Two-arm electron/photon/hadron spectrometer TALES collaboration

    International Nuclear Information System (INIS)

    Hayano, R.S.; Sakurai, H.; Shigaki, K.

    1990-12-01

    To discover and probe the existence of a quark gluon plasma, it would seem desirable to have a detector which is sensitive to as many of the proposed 'signatures' as possible, so that they could all be observed and turned on and off in a predictable, reproducible, controllable and unified way. By emphasizing an open geometry experiment, optimized for detecting low-mass, low P T electron-positron pairs, a reasonably comprehensive measurement of the majority of the quark gluon plasma signatures must be obtained. Thus, the report first addresses physics motivation and goals, focusing on dielectron production; π 0 , η and direct photon measurements; global event characterization; identified hadron P T spectra; and charm production. An overview of the proposed central detector is then presented. Next, major detector components and expected performance are discussed, focusing on tracking, electron-pair reconstruction (a gas ring-imaging Cerenkov RICH counter), Dalitz-decay rejection, a highly-segmented electromagnetic calorimeter, global event characterization, an optical forward spectrometer, and a summary of performance. Finally, the report describes major research and development items and estimated costs. (N.K.)

  9. The ARGUS electron-photon calorimeter. Pt. 1

    International Nuclear Information System (INIS)

    Drescher, A.; Graewe, B.; Hofmann, W.; Markees, A.; Matthiesen, U.; Pollmann, D.; Spengler, J.; Wegener, D.

    1982-05-01

    The performance of the ARGUS shower counters in detecting electromagnetic showers in the energy range 10...45 MeV is reported. When these results are considered with earlier measurements at GeV energies, it is seen that the device behaves almost like an ideal calorimeter over three decades in energy, with good linearity and a 1/√E dependence of the energy resolution. The detection threshold is at least as low as 10 MeV. Characteristics of low-energy electromagnetic showers, such as longitudinal shower profile and fraction of energy visible in the scintillator were measured, and are compared with results obtained from the EGS Monte-Carlo code. (orig)

  10. Linac-based radiosurgery of cerebral melanoma metastases. Analysis of 122 metastases treated in 64 patients

    International Nuclear Information System (INIS)

    Herfarth, K.K.; Pirzkall, A.; Izwekowa, O.; Wannenmacher, M.; Thilmann, C.; Debus, J.; Delorme, S.; Hofmann, U.; Schadendorf, D.; Zierhut, D.

    2003-01-01

    Purpose: Stereotactic radiosurgery is an alternative option to neurosurgical excision in the management of patients with brain metastases. We retrospectively analyzed patients with brain metastases of malignant melanoma who were treated at our institution for outcome and prognostic factors. Patients and Methods: 64 patients with 122 cerebral metastases were treated with stereotactic radiosurgery between 1986 and 2000. Twelve patients (19%) showed neurologic symptoms at the time of treatment, and 46 patients (72%) had extracerebral tumor manifestation at that time. The median dose to the 80% isodose line, prescribed to encompass the tumor margin, was 20 Gy (range, 15-22 Gy). Results: Neurologic symptoms improved in five of twelve symptomatic patients. 41 patients remained asymptomatic or unchanged in their neurologic symptoms. Only five patients (8%) temporarily worsened neurologically after therapy despite no signs of tumor progression. With a mean follow-up time of 9.4 months, actuarial local control was 81% after 1 year. There was a statistically significant dose and size dependency of local tumor control. Median actuarial survival after treatment was 10.6 months. Patients without extracerebral tumor manifestation showed a superior survival (p = 0.04). Conclusions: Despite high local tumor control rates, the prognosis of patients with cerebral metastases of malignant melanoma remains poor. Stereotactic radiosurgery has the potential of stabilizing or improving neurologic symptoms in these patients in a palliative setting. (orig.)

  11. Electron energy device for LINAC based Pulse Radiolysis Facility of RPCD

    International Nuclear Information System (INIS)

    Toley, M.A.; Shinde, S.J.; Chaudhari, B.B.; Sarkar, S.K.

    2015-07-01

    The pulse radiolysis facility is the experimental centerpiece of the radiation chemistry activities of the Radiation and Photochemistry Division (RPCD) of Bhabha Atomic Research Centre. This facility was created in 1986 which is based on a 7 MeV Linear Electron Accelerator (LINAC) procured from M/s Radiation Dynamics Ltd., UK. The electron energy is one of the principal parameters that influence the dose distribution within the sample irradiated with a beam of energetic electrons. An easy-to-use and robust device has been developed that can reliably detect day-today small variations in the beam energy. It consists of two identical aluminum plates except for their thickness, which are electrically insulated from each other. The thickness of each plate is carefully selected depending on the electron beam energy. The charge (or current) collected by each plate, under irradiation is measured. The ratio of the charge (or current) signal from the front plate to the sum of the signals from the front and rear plates is very sensitive to the beam energy. The high sensitivity and robustness make this device quite suitable for Electron energy measurement for Pulse radiolysis Facility at RPCD. (author)

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

    International Nuclear Information System (INIS)

    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.

    2002-01-01

    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 (∼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

  13. 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...

  14. The JAERI superconducting RF linac-based FELS and THEIR cryogenics

    International Nuclear Information System (INIS)

    Minehara, Eisuke J.

    2003-01-01

    In the 21st century, we need a powerful and efficient free-electron laser (FEL) for academic and industrial uses in almost all fields. In order to realize such a tunable, highly-efficient, high average power, high peak power and ultra-short pulse FEL, the JAERI FEL group and I have developed an industrial FEL driven by a compact, stand-alone and zero-boil off super-conducting rf linac with an energy-recovery geometry. Our discussions on the JAERI FEL and cryogenics will cover market-requirements for the industrial FELs, some answers from the JAERI compact, stand-alone and zero-boil off cryostat concept and operational experiences over these 9 years, our discovery of the new, highly-efficient, high-power, and ultra-short pulse lasing mode, and the energy-recovery geometry. (author)

  15. 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.

  16. Conformity of LINAC-Based Stereotactic Radiosurgery Using Dynamic Conformal Arcs and Micro-Multileaf Collimator

    International Nuclear Information System (INIS)

    Hazard, Lisa J.; Wang, Brian; Skidmore, Thomas B.; Chern, Shyh-Shi; Salter, Bill J.; Jensen, Randy L.; Shrieve, Dennis C.

    2009-01-01

    Purpose: To assess the conformity of dynamic conformal arc linear accelerator-based stereotactic radiosurgery and to describe a standardized method of isodose surface (IDS) selection. Methods and Materials: In 174 targets, the conformity index (CI) at the prescription IDS used for treatment was calculated as CI = (PIV/PVTV)/(PVTV/TV), where TV is the target volume, PIV (prescription isodose volume) is the total volume encompassed by the prescription IDS, and PVTV is the TV encompassed by the IDS. In addition, a 'standardized' prescription IDS (sIDS) was chosen according to the following criteria: 95% of the TV was encompassed by the PIV and 99% of TV was covered by 95% of the prescription dose. The CIs at the sIDS were also calculated. Results: The median CI at the prescription IDS and sIDS was 1.63 and 1.47, respectively (p < 0.001). In 132 of 174 cases, the volume of normal tissue in the PIV was reduced by the prescription to the sIDS compared with the prescription IDS, in 20 cases it remained unchanged, and in 22 cases it was increased. Conclusion: The CIs obtained with linear accelerator-based stereotactic radiosurgery are comparable to those previously reported for gamma knife stereotactic radiosurgery. Using a uniform method to select the sIDS, adequate target coverage was usually achievable with prescription to an IDS greater than that chosen by the treating physician (prescription IDS), providing sparing of normal tissue. Thus, the sIDS might aid physicians in identifying a prescription IDS that balances coverage and conformity

  17. Initial clinical results of linac-based stereotactic radiosurgery and stereotactic radiotherapy for pituitary adenomas

    International Nuclear Information System (INIS)

    Mitsumori, Michihide; Shrieve, Dennis C.; Alexander, Eben; Kaiser, Ursula B.; Richardson, Gary E.; Black, Peter McL.; Loeffler, Jay S.

    1998-01-01

    Purpose: To retrospectively evaluate the initial clinical results of stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (SRT) for pituitary adenomas with regard to tumor and hormonal control and adverse effects of the treatment. Subjects and Methods: Forty-eight patients with pituitary adenoma who underwent SRS or SRT between September 1989 and September 1995 were analyzed. Of these, 18 received SRS and 30 received SRT. The median tumor volumes were 1.9 cm 3 for SRS and 5.7 cm 3 for SRT. Eleven of the SRS and 18 of the SRT patients were hormonally active at the time of the initial diagnosis. Four of the SRS and none of the SRT patients had a history of prior radiation therapy. Both SRS and SRT were performed using a dedicated stereotactic 6-MV linear accelerator (LINAC). The dose and normalization used for the SRS varied from 1000 cGy at 85% of the isodose line to 1500 cGy at 65% of the isodose line. For SRT patients, a total dose of 4500 cGy at 90% or 95% of the isodose line was delivered in 25 fractions of 180 cGy daily doses. Results: Disease control--The three year tumor control rate was 91.1% (100% for SRS and 85.3% for SRT). Normalization of the hormonal abnormality was achieved in 47% of the 48 patients (33% for SRS and 54% for SRT). The average time required for normalization was 8.5 months for SRS and 18 months for SRT. Adverse effects--The 3-year rate of freedom from central nervous system adverse effects was 89.7% (72.2% for SRS and 100% for SRT). Three patients who received SRS for a tumor in the cavernous sinus developed a ring enhancement in the temporal lobe as shown by follow-up magnetic resonance imaging. Two of these cases were irreversible and were considered to be radiation necrosis. None of the 48 patients developed new neurocognitive or visual disorders attributable to the irradiation. The incidence of endocrinological adverse effects were similar in the two groups, resulting in 3-year rates of freedom from newly initiated hormonal replacement of 78.4% (77.1% for SRS and 79.9% for SRT). Conclusion: Considering the relatively high incidence of morbidity observed in the SRS group, we recommend SRT as the primary method of radiation therapy for pituitary tumors. When treating a lesion in the cavernous sinus with SRS, special attention should be paid to dose distribution in the adjacent brain parenchyma. Longer follow-up is necessary before drawing any conclusions about the advantages of these techniques over conventional external beam radiation therapy

  18. Design and simulation of an optimized e-linac based neutron source for BNCT research

    International Nuclear Information System (INIS)

    Durisi, E.; Alikaniotis, K.; Borla, O.; Bragato, F.; Costa, M.; Giannini, G.; Monti, V.; Visca, L.; Vivaldo, G.; Zanini, A.

    2015-01-01

    The paper is focused on the study of a novel photo-neutron source for BNCT preclinical research based on medical electron Linacs. Previous studies by the authors already demonstrated the possibility to obtain a mixed thermal and epithermal neutron flux of the order of 10"7 cm"−"2 s"−"1. This paper investigates possible Linac’s modifications and a new photo-converter design to rise the neutron flux above 5 10"7 cm"−"2 s"−"1, also reducing the gamma contamination. - Highlights: • Proposal of a mixed thermal and epithermal (named hyperthermal) neutron source based on medical high energy electron Linac. • Photo-neutron production via Giant Dipole Resonance on high Z materials. • MCNP4B-GN simulations to design the photo-converter geometry maximizing the hyperthermal neutron flux and minimizing the fast neutron and gamma contaminations. Hyperthermal neutron field suitable for BNCT preclinical research.

  19. 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.

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

    International Nuclear Information System (INIS)

    Muramatsu, Julia; Yoshida, Masanori; Shioura, Hiroki; Kawamura, Yasutaka; Ito, Harumi; Takeuchi, Hiroaki; Kubota, Toshihiko; Maruyama, Ichiro

    2003-01-01

    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)

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

    International Nuclear Information System (INIS)

    Liu, B; Zhang, L; Rigor, N; Kim, J

    2015-01-01

    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

  2. Quantitative assessment of multi-isocentric radiosurgical irradiation based on the f factor

    International Nuclear Information System (INIS)

    Lefkopoulos, D.; Schlienger, M.; Hancilar, T.; Keraudy, K.; Touboul, E.

    1995-01-01

    To evaluate quantitatively the stereotactic irradiations, we defined a DVH parameter (f) resulting from the lesion underdosage and healthy tissues overdosage curves. The Lesion Underdose Factor (LUF) is the ratio of the lesion volume receiving dose inferior to a reference isodose to the lesion volume. The Healthy Tissue Overdose Factor HTOF quantitates the amount of tissue external to the lesion receiving dose equal to or greater than a given reference isodose relatively to the lesion volume. The LUF and HTOF curves represent the variation of the LUF and HTOF factors as a function of the reference isodose. The f factor is the surface situated below the intersection of the two curves. The optimization goal of the planification procedure could consist in the minimization of f. We have correlated them with clinical results (obliteration of the nidus) of a series of 34 multi-isocenters AVMs linac irradiation. The treatment dose protocol was a peripheral dose of 20 - 25 Gy (50 to 70% isodose range). According to this preliminary study, it seems that f factor provides clinically useful quantitative indices for the treatment plan evaluation. The choice of the optimal treatment plan and reference isodose is realized as follows. For a same patient different treatment plans are calculated by successive modifications of the irradiation parameters, as the number of isocenters, the distances between isocenters, the collimators diameter, the number of arcs and their angular length etc. The choice of optimal treatment plan is based on a clinically validated quantitative factor such as the f factor. According to our preliminary results one should select the treatment plan corresponding to the smallest value of f. The choice of the optimal reference isodose is based on the clinical data (lesion volume and topography, adjacent critical structures) and the LUF and HTOF factors following a well-defined protocol

  3. Craniospinal treatment with IMRT multi-isocentric and image-guided linear accelerator based on Gantry

    International Nuclear Information System (INIS)

    Sanz Beltran, M.; Caballero Perea, B.; Rodriguez Rodriguez, C.; Arminio Diaz, E.; Lopez Fernandez, A.; Gomez Fervienza, J. R.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.; Gomez Fervienza, J. r.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.

    2011-01-01

    The objective is the realization of craniospinal treatment with a linear accelerator equipped with gantry based on MLC, carbon fiber table and Image Guided capability. The great length of treatment (patient l,80m in height) was a great difficulty for want of full length of the longitudinal movement of the table to adequately cover the PTV, plus free metallic screws fastening the head of the table extender preventing further incidents.

  4. Magnetoresistance of non-180° domain wall in the presence of electron-photon interaction

    Science.gov (United States)

    Majidi, Roya

    2013-04-01

    In the present paper, influence of photon on resistance of non-180° domain wall in metallic magnetic nanowires has been studied using the semiclassical approach. The analysis has been based on the Boltzmann transport equation, within the relaxation time approximation. The one-dimensional Néel-type domain wall between two ferromagnetic domains with relative magnetization angle less than 180° is considered. By increasing this angle, the contribution of the domain wall in the resistivity of the nanowire becomes considerable. It is also found that the fundamental contribution of the domain wall in resistivity can be controlled by propagating photon. These results are valuable in designing spintronic devices based on magnetic nanowires.

  5. First results from electron-photon damage equivalence studies on a generic ethylene-propylene rubber

    International Nuclear Information System (INIS)

    Buckalew, W.H.

    1986-04-01

    As part of a simulator adequacy assessment program, the relative effectiveness of electrons and photons to produce damage in a generic ethylene propylene rubber (EPR) has been investigated. The investigation was limited in extent in that a single EPR material, in three thickness, was exposed to Cobalt-60 photons and three electron beam energies. Basing material damage on changes in the EPR mechanical properties elongation and tensile strength, we observed that EPR damage was a smoothly varying function of absorbed energy and independent of irradiating particle type. EPR damage tracked equally well as a function of both incident particle energy and material front surface dose. Based on these preliminary data, we tentatively concluded that a correlation between particle, particle energy, and material damage (as measured by changes in material elongation and/or tensile strength) has been demonstrated. 14 figs

  6. Nanotechnology and neuroscience nano-electronic, photonic and mechanical neuronal interfacing

    CERN Document Server

    Martiradonna, Luigi; Assad, John

    2014-01-01

     This book provides an overview of the different ways in which the “nano-world” can be beneficial for neuroscientists. The volume encompasses the latest developments in the field of micro- and nanotechnology applied to neuroscience, discussing technological approaches applied to both in-vitro and in-vivo experiments. A variety of different nanotechnologies are presented that include nanostructured electrodes and their electrical, mechanical and biochemical properties, active and passive 2D and 3D multi-electrode arrays (MEAs), nanoscale transistors for sub-cellular re-cordings and an overview on methods, tools and applications in optoge-netics. The book focuses specifically on fabrication strategies, to offer a compre-hensive guide for developing and applying micro- and nanostructured tools for neuroscientific applications. It is intended as a reference both for neuroscientists and nanotechnologists on the latest developments in neu-rotechnological tools.   • Provides readers with state-of-the-art in...

  7. Nuclear physics with laser-electron-photons. Developments and perspectives at SPring-8

    International Nuclear Information System (INIS)

    Fujiwara, Mamoru

    1998-01-01

    By the Compton scattering with ultraviolet laser beam using the 8 GeV electron beam of the SPring-8, the photon beam which is polarized by nearly 100% is obtained in 1-3.5 GeV region. The quark nuclear physics research at this facility is unique in the world, and it is expected that in the experiment at the SPring-8, the collision phenomena of polarized, high energy gamma-ray and the quarks in nucleons and the knockout phenomena of quarks are observed. Also the polarization experiment for clarifying ''the origin of nucleon spin'' has been proposed. Japan can stand at the top in the world in the research of quark nuclear physics with leptons. In the inverse Compton scattering using far infrared laser, the gamma-ray with good directionality of MeV range is obtained, and it will be applied widely to the research on E1 resonance and M1 excitation of atomic nuclei. In this report, the medium energy quark nuclear physics developed at the SPring-8 is outlined, and the nuclear physics which is expected to be developed when the high intensity, high polarization gamma-ray of about 10 MeV is generated is discussed. The detection of s, anti-s components in nucleons, research on baryon deformation and baryon spectra, verification of the Gerasimov, Drell-Hearn law of sum, meson structure, test of quark model by the photolysis of deuterons, dual Ginzburg Landau theory exploration, research on the mass and behavior of mesons in nuclear media are discussed. (K.I.)

  8. Electrons, Photons, and Force: Quantitative Single-Molecule Measurements from Physics to Biology

    Science.gov (United States)

    2011-01-01

    Single-molecule measurement techniques have illuminated unprecedented details of chemical behavior, including observations of the motion of a single molecule on a surface, and even the vibration of a single bond within a molecule. Such measurements are critical to our understanding of entities ranging from single atoms to the most complex protein assemblies. We provide an overview of the strikingly diverse classes of measurements that can be used to quantify single-molecule properties, including those of single macromolecules and single molecular assemblies, and discuss the quantitative insights they provide. Examples are drawn from across the single-molecule literature, ranging from ultrahigh vacuum scanning tunneling microscopy studies of adsorbate diffusion on surfaces to fluorescence studies of protein conformational changes in solution. PMID:21338175

  9. Nuclear physics with laser-electron-photons. Developments and perspectives at SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Mamoru [Osaka Univ., Ibaraki (Japan). Research Center for Nuclear Physics

    1998-03-01

    By the Compton scattering with ultraviolet laser beam using the 8 GeV electron beam of the SPring-8, the photon beam which is polarized by nearly 100% is obtained in 1-3.5 GeV region. The quark nuclear physics research at this facility is unique in the world, and it is expected that in the experiment at the SPring-8, the collision phenomena of polarized, high energy gamma-ray and the quarks in nucleons and the knockout phenomena of quarks are observed. Also the polarization experiment for clarifying ``the origin of nucleon spin`` has been proposed. Japan can stand at the top in the world in the research of quark nuclear physics with leptons. In the inverse Compton scattering using far infrared laser, the gamma-ray with good directionality of MeV range is obtained, and it will be applied widely to the research on E1 resonance and M1 excitation of atomic nuclei. In this report, the medium energy quark nuclear physics developed at the SPring-8 is outlined, and the nuclear physics which is expected to be developed when the high intensity, high polarization gamma-ray of about 10 MeV is generated is discussed. The detection of s, anti-s components in nucleons, research on baryon deformation and baryon spectra, verification of the Gerasimov, Drell-Hearn law of sum, meson structure, test of quark model by the photolysis of deuterons, dual Ginzburg Landau theory exploration, research on the mass and behavior of mesons in nuclear media are discussed. (K.I.)

  10. Optimal beam margins in linac-based VMAT stereotactic ablative body radiotherapy: a Pareto front analysis for liver metastases.

    Science.gov (United States)

    Cilla, Savino; Ianiro, Anna; Deodato, Francesco; Macchia, Gabriella; Digesù, Cinzia; Valentini, Vincenzo; Morganti, Alessio G

    2017-11-27

    We explored the Pareto fronts mathematical strategy to determine the optimal block margin and prescription isodose for stereotactic body radiotherapy (SBRT) treatments of liver metastases using the volumetric-modulated arc therapy (VMAT) technique. Three targets (planning target volumes [PTVs] = 20, 55, and 101 cc) were selected. A single fraction dose of 26 Gy was prescribed (prescription dose [PD]). VMAT plans were generated for 3 different beam energies. Pareto fronts based on (1) different multileaf collimator (MLC) block margin around PTV and (2) different prescription isodose lines (IDL) were produced. For each block margin, the greatest IDL fulfilling the criteria (95% of PTV reached 100%) was considered as providing the optimal clinical plan for PTV coverage. Liver D mean , V7Gy, and V12Gy were used against the PTV coverage to generate the fronts. Gradient indexes (GI and mGI), homogeneity index (HI), and healthy liver irradiation in terms of D mean , V7Gy, and V12Gy were calculated to compare different plans. In addition, each target was also optimized with a full-inverse planning engine to obtain a direct comparison with anatomy-based treatment planning system (TPS) results. About 900 plans were calculated to generate the fronts. GI and mGI show a U-shaped behavior as a function of beam margin with minimal values obtained with a +1 mm MLC margin. For these plans, the IDL ranges from 74% to 86%. GI and mGI show also a V-shaped behavior with respect to HI index, with minimum values at 1 mm for all metrics, independent of tumor dimensions and beam energy. Full-inversed optimized plans reported worse results with respect to Pareto plans. In conclusion, Pareto fronts provide a rigorous strategy to choose clinical optimal plans in SBRT treatments. We show that a 1-mm MLC block margin provides the best results with regard to healthy liver tissue irradiation and steepness of dose fallout. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  11. Ultrafast harmonic rf kicker design and beam dynamics analysis for an energy recovery linac based electron circulator cooler ring

    Directory of Open Access Journals (Sweden)

    Yulu Huang

    2016-08-01

    Full Text Available An ultrafast kicker system is being developed for the energy recovery linac (ERL based electron circulator cooler ring (CCR in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously named MEIC. In the CCR, the injected electron bunches can be recirculated while performing ion cooling for 10–30 turns before the extraction, thus reducing the recirculation beam current in the ERL to 1/10−1/30 (150  mA-50  mA of the cooling beam current (up to 1.5 A. Assuming a bunch repetition rate of 476.3 MHz and a recirculating factor of 10 in the CCR, the kicker is required to operate at a pulse repetition rate of 47.63 MHz with pulse width of around 2 ns, so that only every 10th bunch in the CCR will experience a transverse kick while the rest of the bunches will not be disturbed. Such a kicker pulse can be synthesized by ten harmonic modes of the 47.63 MHz kicker pulse repetition frequency, using up to four quarter wavelength resonator (QWR based deflecting cavities. In this paper, several methods to synthesize such a kicker waveform will be discussed and a comparison of their beam dynamics performance is made using ELEGANT. Four QWR cavities are envisaged with high transverse shunt impedance requiring less than 100 W of total rf power for a Flat-Top kick pulse. Multipole fields due to the asymmetry of this type of cavity are analyzed. The transverse emittance growth due to the sextupole component is simulated in ELEGANT. Off-axis injection and extraction issues and beam optics using a multicavity kick-drift scheme will also be discussed.

  12. 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...

  13. 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.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 5·10 11 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Muranaka, T; Debu, P; Dupre, P; Liszkay, L; Mansoulie, B; Perez, P; Rey, J M; Ruiz, N; Sacquin, Y [Irfu, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Crivelli, P; Gendotti, U; Rubbia, A, E-mail: tomoko.muranaka@cea.f [Institut fuer TelichenPhysik, ETHZ, CH-8093 Zuerich (Switzerland)

    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{center_dot}10{sup 11} 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.

  16. SU-E-J-239: IMRT Planning of Prostate Cancer for a MRI-Linac Based On MRI Only

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X; Prior, P; Paulson, E; Lawton, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2014-06-01

    Purpose: : To investigate dosimetric differences between MRI- and CT-based IMRT planning for prostate cancer, the impact of a magnetic field in a MRI-Linac, and to explore the feasibility of IMRT planning based on MRI alone. Methods: IMRT plans were generated based on CT and MRI images acquired on two representative prostate-cancer patients using clinical dose volume constraints. A research planning system (Monaco, Elekta), which employs a Monte Carlo dose engine and includes a perpendicular magnetic field of 1.5T from an MRI-Linac, was used. Bulk electron density assignments based on organ-specific values from ICRU 46 were used to convert MRI (T2) to pseudo CT. With the same beam configuration as in the original CT plan, 5 additional plans were generated based on CT or MRI, with or without optimization (i.e., just recalculation) and with or without the magnetic field. The plan quality in terms of commonly used dose volume (DV) parameters for all plans was compared. The statistical uncertainty on dose was < 1%. Results: For plans with the same contour set but without re-optimization, the DV parameters were different from those for the original CT plan, mostly less than 5% with a few exceptions. These differences were reduced to mostly less than 3% when the plans were re-optimized. For plans with contours from MRI, the differences in the DV parameters varied depending on the difference in the contours as compared to CT. For the optimized plans with contours from MR, the differences for PTV were less than 3%. Conclusion: The prostate IMRT plans based on MRI-only for a MR-Linac were practically similar as compared to the CT plan under the same beam and optimization configuration if the difference on the structure delineation is excluded, indicating the feasibility of using MRI-only for prostate IMRT.

  17. 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.

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

    International Nuclear Information System (INIS)

    Geraghty, C; Workie, D; Hasson, B

    2015-01-01

    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

  19. A program for monitor unit calculation for high energy photon beams in isocentric condition based on measured data

    International Nuclear Information System (INIS)

    Gesheva-Atanasova, N.

    2008-01-01

    The aim of this study is: 1) to propose a procedure and a program for monitor unit calculation for radiation therapy with high energy photon beams, based on data measured by author; 2) to compare this data with published one and 3) to evaluate the precision of the monitor unit calculation program. From this study it could be concluded that, we reproduced with a good agreement the published data, except the TPR values for dept up to 5 cm. The measured relative weight of upper and lower jaws - parameter A was dramatically different from the published data, but perfectly described the collimator exchange effect for our treatment machine. No difference was found between the head scatter ratios, measured in a mini phantom and those measured with a proper brass buildup cap. Our monitor unit calculation program was found to be reliable and it can be applied for check up of the patient's plans for irradiation with high energy photon beams and for some fast calculations. Because of the identity in the construction, design and characteristics of the Siemens accelerators, and the agreement with the published data for the same beam qualities, we hope that most of our experimental data and this program can be used after verification in other hospitals

  20. ‘Inverted Y’ field radiotherapy planning with multi-leaf collimator: A single isocentric technique using multiple fields

    Directory of Open Access Journals (Sweden)

    Puja Sahai

    2015-01-01

    Full Text Available The purpose of our study is to describe a planning technique using multi-leaf collimator and asymmetric fields for irradiating an ‘inverted Y’ shaped geometry in a patient with testicular seminoma. The entire target area covering the para-aortic, pelvic, and inguinal nodal regions was split into three fields. Single isocenter half-beam block technique was employed. The fields were planned with antero-posterior and postero-anterior portals with a differential weightage. The dose was prescribed at the respective reference points of the fields. A uniform dose distribution for the entire portal was achieved without any under- or over-dosing at the field junctions.  

  1. Lifetimes of some 4p levels of Ne I obtained by two-step (electron-photon) excitation

    International Nuclear Information System (INIS)

    Ortiz, M.; Garcia, G.; Blanco, F.; Campos, J.

    1990-01-01

    Radiative lifetimes of some levels belonging to 2p 5 4p configuration of Ne I have been determined using electron excitation followed by selective laser excitation. The experimental results of this work are 123.8±3.6 ns, 120.3±2.8 ns and 135.9±4.5 ns for the 4p'(3/2) 1 , 4p'(1/2) 1 and 4p(5/2) 2 levels respectively. (orig.)

  2. Integrated Tiger Series of electron/photon Monte Carlo transport codes: a user's guide for use on IBM mainframes

    International Nuclear Information System (INIS)

    Kirk, B.L.

    1985-12-01

    The ITS (Integrated Tiger Series) Monte Carlo code package developed at Sandia National Laboratories and distributed as CCC-467/ITS by the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory (ORNL) consists of eight codes - the standard codes, TIGER, CYLTRAN, ACCEPT; the P-codes, TIGERP, CYLTRANP, ACCEPTP; and the M-codes ACCEPTM, CYLTRANM. The codes have been adapted to run on the IBM 3081, VAX 11/780, CDC-7600, and Cray 1 with the use of the update emulator UPEML. This manual should serve as a guide to a user running the codes on IBM computers having 370 architecture. The cases listed were tested on the IBM 3033, under the MVS operating system using the VS Fortran Level 1.3.1 compiler

  3. Theory of electron--photon scattering effects in metals. Progress report, December 1, 1976--November 30, 1977

    International Nuclear Information System (INIS)

    Lawrence, W.E.

    1977-01-01

    The general areas in which the investigations were carried out are transport properties and quasiparticle lifetimes in normal metals and superconductors. The more specific research projects upon which progress is reported are (a) the calculation of order parameter relaxation times in aluminum, (b) transport coefficients of the noble metals (emphasizing deviations from Matthiessen's rule), (c) variational transport calculations for a superconductor, (d) some general results on quasiparticle relaxation time anisotropy in polyvalent metals, and (e) a clarification of the roles of electron-electron and electron-phonon scattering in somple metals at low temperatures

  4. Scintillating liquid xenon calorimeter for precise electron/photon/jet physics at high energy high luminosity hadron colliders

    International Nuclear Information System (INIS)

    Chen, M.; Luckey, D.; Pelly, D.; Shotkin, S.; Sumorok, K.; Wadsworth, B.; Yan, X.J.; You, C.; Zhang, X.; Chen, E.G.; Gaudreau, M.P.J.; Montgomery, D.B.; Sullivan, J.D.; Bolozdynya, A.; Chernyshev, V.; Goritchev, P.; Khovansky, V.; Kouchenkov, A.; Kovalenko, A.; Lebedenko, V.; Vinogradov, V.A.; Epstein, V.; Zeldovich, S.; Krasnokutsky, R.; Shuvalov, R.; Aprile, E.; Mukherjee, R.; Suzuki, M.; Moulsen, M.; Sugimoto, S.; Okada, K.; Fujino, T.; Matsuda, T.; Miyajima, M.; Doke, T.; Kikuchi, J.; Hitachi, A.; Kashiwagi, T.; Nagasawa, Y.; Ichinose, H.; Ishida, N.; Nakasugi, T.; Ito, T.; Masuda, K.; Shibamura, E.; Wallraff, W.; Vivargent, M.; Mutterer, M.; Chen, H.S.; Tang, H.W.; Tung, K.L.; Ding, H.L.; Takahashi, T.

    1990-01-01

    The authors use αs well as e, π, p, d and heavy ion beams to test prototype scintillating liquid xenon detectors, with large UV photodiodes and fast amplifiers submersed directly in liquid xenon. The data show very large photoelectron yields (10 7 /GeV) and high energy resolution (σ(E)/E 1.6 GeV). The α spectra are stable over long term and can be used to calibrate the detectors. Full size liquid xenon detectors have been constructed, to study cosmic μ's and heavy ions. The authors report the progress on the design and construction of the 5 x 5 and 11 x 11 cell liquid xenon detectors which will be tested in high energy beams to determine the e/π ratio. The authors describe the design and the unique properties of the proposed scintillating LXe calorimeter for the SSC

  5. 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.

  6. Application of the extreme value theory to beam loss estimates in the SPIRAL2 linac based on large scale Monte Carlo computations

    Directory of Open Access Journals (Sweden)

    R. Duperrier

    2006-04-01

    Full Text Available The influence of random perturbations of high intensity accelerator elements on the beam losses is considered. This paper presents the error sensitivity study which has been performed for the SPIRAL2 linac in order to define the tolerances for the construction. The proposed driver aims to accelerate a 5 mA deuteron beam up to 20   A MeV and a 1 mA ion beam for q/A=1/3 up to 14.5 A MeV. It is a continuous wave regime linac, designed for a maximum efficiency in the transmission of intense beams and a tunable energy. It consists in an injector (two   ECRs   sources+LEBTs with the possibility to inject from several sources+radio frequency quadrupole followed by a superconducting section based on an array of independently phased cavities where the transverse focalization is performed with warm quadrupoles. The correction scheme and the expected losses are described. The extreme value theory is used to estimate the expected beam losses. The described method couples large scale computations to obtain probability distribution functions. The bootstrap technique is used to provide confidence intervals associated to the beam loss predictions. With such a method, it is possible to measure the risk to loose a few watts in this high power linac (up to 200 kW.

  7. Differences in Clinical Results After LINAC-Based Single-Dose Radiosurgery Versus Fractionated Stereotactic Radiotherapy for Patients With Vestibular Schwannomas

    International Nuclear Information System (INIS)

    Combs, Stephanie E.; Welzel, Thomas; Schulz-Ertner, Daniela; Huber, Peter E.; Debus, Juergen

    2010-01-01

    Purpose: To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS). Methods and Materials: This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a median total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose. Results: FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of ≤13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (≤13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of ≤13 Gy, cranial nerve toxicity was comparable to that of the FSRT group. Conclusions: FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of ≤13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.

  8. In-vivo dosimetry with Gafchromic films for multi-isocentric VMAT irradiation of total marrow lymph-nodes: a feasibility study

    International Nuclear Information System (INIS)

    Mancosu, Pietro; Navarria, Pierina; Reggiori, Giacomo; Cozzi, Luca; Fogliata, Antonella; Gaudino, Anna; Lobefalo, Francesca; Paganini, Lucia; Palumbo, Valentina; Sarina, Barbara; Stravato, Antonella; Castagna, Luca; Tomatis, Stefano; Scorsetti, Marta

    2015-01-01

    Total marrow (lymph-nodes) irradiation (TMI-TMLI) by volumetric modulated arc therapy (VMAT) was shown to be feasible by dosimetric feasibility studies. It was demonstrated that several partially overlapping arcs with different isocenters are required to achieve the desired coverage of the hematopoietic or lymphoid tissues targets and to spare the neighbouring healthy tissues. The effect of isocenter shifts was investigated with the treatment planning system but an in- vivo verification of the procedure was not carried out. The objective of this study was the in-vivo verification of the consistency between the delivered and planned doses using bi-dimensional GafChromic EBT3 films. In a first phase a phantom study was carried out to quantify the uncertainties under controlled conditions. In a second phase three patients treated with TMLI were enrolled for in-vivo dosimetry. The dose prescription was 2Gy in single fraction. Ten arcs paired on 4-6 isocenters were used to cover the target. Cone Beam Computed Tomography (CBCT) was used to verify the patient positioning at each isocenter. GafChromic EBT3 films were placed below the patient on the top of a dedicated immobilization system specifically designed. The dose maps measured with the EBT3 films were compared with the corresponding calculations along the patient support couch. Gamma Agreement Index (GAI) with dose difference of 5% and distance to agreement of 5 mm was computed. In the phantom study, optimal target coverage and healthy tissue sparing was observed. GAI(5%,5 mm) was 99.4%. For the patient-specific measurements, GAI(5%,5 mm) was greater than 95% and GAI (5%,3 mm) > 90% for all patients. In vivo measurements demonstrated the delivered dose to be in good agreement with the planned one for the TMI-TMLI protocol where partially overlapping arcs with different isocenters are required

  9. ICNBME-2011: International Conference on Nanotechnologies and Biomedical Engineering; German-Moldovan Workshop on Novel Nanomaterials for Electronic, Photonic and Biomedical Applications. Proceedings

    International Nuclear Information System (INIS)

    Tiginyanu, Ion; Sontea, Victor

    2011-01-01

    This book includes articles which cover a vast range of subjects, such as: nano technologies and nano materials, micro- and nano-objects, nanostructured and highly integrated systems, biophysics, biomedical instrumentation and devices, biomaterials, medical imaging, information technologies for health care, tele medicine, etc.

  10. ICNBME-2013: 2. international conference on nanotechnologies and biomedical engineering; German-Moldovan workshop on novel nanomaterials for electronic, photonic and biomedical applications. Proceedings

    International Nuclear Information System (INIS)

    Tiginyanu, Ion; Sontea, Victor

    2013-01-01

    This book includes articles which cover a vast range of subjects, such as: nano technologies and nano materials, micro- and nano-objects, nanostructured and highly integrated systems, biophysics, biomedical instrumentation and devices, biomaterials, medical imaging, information technologies for health care, tele medicine, etc.

  11. XRAY applied program package for calculation of electron-photon fields in the energy range of 1-1000 keV

    International Nuclear Information System (INIS)

    Lappa, A.V.; Khadyeva, Z.M.; Burmistrov, D.S.; Vasil'ev, O.N.

    1990-01-01

    The package of applied XRAY programs is intended for calculating the linear and fluctuation characteristics of photon and electron radiation fields in heterogeneous medium within 1-1000 keV energy range. The XRAY program package consists of moduli written in FORTRAN-IV and data files. 9 refs

  12. Search for Leptoquarks in Electron-Photon Scattering at $\\sqrt{s_{ee}}$ up to 209 GeV at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Couchman, J.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Dervan, P.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kormos, Laura L.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Littlewood, C.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rozen, Y.; Runge, K.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Sproston, M.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomas, J.; Thomson, M.A.; Torrence, E.; Toya, D.; Trefzger, T.; Tricoli, A.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, G.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    2002-01-01

    Searches for first generation scalar and vector leptoquarks, and for squarks in R-parity violating SUSY models with the direct decay of the squark into Standard Model particles, have been performed using e+e- collisions collected with the OPAL detector at LEP at e+e- centre-of-mass energies between 189 and 209 GeV. No excess of events is found over the expectation from Standard Model background processes. Limits are computed on the leptoquark couplings for different values of the branching ratio to electron-quark final states.

  13. Efficient and accurate simulations of two-dimensional electronic photon-echo signals: Illustration for a simple model of the Fenna-Matthews-Olson complex

    International Nuclear Information System (INIS)

    Sharp, Leah Z.; Egorova, Dassia; Domcke, Wolfgang

    2010-01-01

    Two-dimensional (2D) photon-echo spectra of a single subunit of the Fenna-Matthews-Olson (FMO) bacteriochlorophyll trimer of Chlorobium tepidum are simulated, employing the equation-of-motion phase-matching approach (EOM-PMA). We consider a slightly extended version of the previously proposed Frenkel exciton model, which explicitly accounts for exciton coherences in the secular approximation. The study is motivated by a recent experiment reporting long-lived coherent oscillations in 2D transients [Engel et al., Nature 446, 782 (2007)] and aims primarily at accurate simulations of the spectroscopic signals, with the focus on oscillations of 2D peak intensities with population time. The EOM-PMA accurately accounts for finite pulse durations as well as pulse-overlap effects and does not invoke approximations apart from the weak-field limit for a given material system. The population relaxation parameters of the exciton model are taken from the literature. The effects of various dephasing mechanisms on coherence lifetimes are thoroughly studied. It is found that the experimentally detected multiple frequencies in peak oscillations cannot be reproduced by the employed FMO model, which calls for the development of a more sophisticated exciton model of the FMO complex.

  14. Measurement of thermal neutron cross-section and resonance integral for the 165Ho(n,γ) 166gHo reaction using electron linac-based neutron source

    Science.gov (United States)

    Nguyen, Van Do; Pham, Duc Khue; Kim, Tien Thanh; Kim, Guinyun; Lee, Manwoo; Kim, Kyung Sook; Kang, Heung-Sik; Cho, Moo-Hyun; Ko, In Soo; Namkung, Won

    2011-01-01

    The thermal neutron cross-section and the resonance integral of the 165Ho(n,γ) 166gHo reaction have been measured by the activation method using a 197Au(n,γ) 198Au monitor reaction as a single comparator. The high-purity natural Ho and Au foils with and without a cadmium shield case of 0.5 mm thickness were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a calibrated p-type high-purity Ge detector. The correction factors for the γ-ray attenuation ( Fg), the thermal neutron self-shielding ( Gth), the resonance neutron self-shielding ( Gepi) effects, and the epithermal neutron spectrum shape factor ( α) were taken into account. The thermal neutron cross-section for the 165Ho(n,γ) 166gHo reaction has been determined to be 59.7 ± 2.5 barn, relative to the reference value of 98.65 ± 0.09 barn for the 197Au(n,γ) 198Au reaction. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral for the 165Ho(n,γ) 166gHo reaction is 671 ± 47 barn, which is determined relative to the reference value of 1550 ± 28 barn for the 197Au(n,γ) 198Au reaction. The present results are, in general, good agreement with most of the previously reported data within uncertainty limits.

  15. Craniospinal treatment with IMRT multi-isocentric and image-guided linear accelerator based on Gantry; Tratamiento craneoespinal multi-isocentrico con IMRT y guiado por imagen en acelerador lineal basado en Gantry

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Beltran, M.; Caballero Perea, B.; Rodriguez Rodriguez, C.; Arminio Diaz, E.; Lopez Fernandez, A.; Gomez Fervienza, J. R.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.; Gomez Fervienza, J. r.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.

    2011-07-01

    The objective is the realization of craniospinal treatment with a linear accelerator equipped with gantry based on MLC, carbon fiber table and Image Guided capability. The great length of treatment (patient l, 80m in height) was a great difficulty for want of full length of the longitudinal movement of the table to adequately cover the PTV, plus free metallic screws fastening the head of the table extender preventing further incidents.

  16. [3-D reconstruction of the breast implants from isocentric stereoscopic x-ray images for the application monitoring and irradiation planning of a remote-controlled interstitial afterloading method].

    Science.gov (United States)

    Löffler, E; Sauer, O

    1988-01-01

    An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using 192Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45 degrees, depending on the importance given to the individual parts and almost without being influenced by the relation between the isocenter-film and the focus-isocenter distances. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

  17. Three-dimensional reconstruction of breast implants based on isocentric stereoscopic X-ray pictures (ISXP) for application monitoring and irradiation planning of a remote-controlled interstitial afterloading method

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, E.; Sauer, O.

    1988-01-01

    An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using /sup 192/Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45/sup 0/, depending on the importance given to the individual parts and almost without being influenced by the relation between the distance isocenter-film and the distance focus-isocenter. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

  18. Radiation dose in critical organs due to non-coplanar irradiation of the pituitary gland

    International Nuclear Information System (INIS)

    Schulte, R.W.M.; Rittmann, K.L.; Meinass, H.J.; Rennicke, P.

    1996-01-01

    In order to estimate the somatic and genetic risk associated with a non-coplanar linac-based radiation technique of the pituitary gland, systematic secondary-dose measurements in a phantom and sample measurements of the dose near critical organs of patients were performed. For measurements of the dose outside the primary radiation field an acrylic-PVC phantom was used which was irradiated with a single field (4x4 cm 2 ). Eight patients with pituitary tumors were treated isocentrically with a combination of sagittal and transverse rotational arcs. To measure the dose in critical organs, LiF thermoluminescence dosimeters (TLD) in chip form were placed onto 1 eyelid, the skin over the thyroid, and the patient's clothes covering the region of breasts and ovaries of female patients and the testicles of male patients. Measurements were performed for all patients during 1 sagittal irradiation and for the majority of patients during 1 transverse irradiation. The phantom measurements demonstrated that the secondary dose measured on the patients surface can be considered as a good approximation for the dose in adjacent organs. The median dose in critical organs for sagittal irradiation was in the range of 25.8 mGy (eyes) to 1.9 mGy (testicles), and for transverse irradiation in the range of 23.3 mGy (eyes) to 1.3 mGy (testicles). The ratio of median organ doses for sagittal and transverse irradiation was 2.1 for the thyroid gland, 1.1 for the eyes, and 1.5 for the other organs. The dose in critical organs due to non-coplanar irradiation of the pituitary gland is only a small fraction of the dose delivered to the reference point of the planning target volume. The risk of a radiation-induced tumor and a genetic consequence associated with these small doses is generally less than 1% and 0.1%, respectively. (orig./MG) [de

  19. Quality Assurance Results for a Commercial Radiosurgery System: A Communication.

    Science.gov (United States)

    Ruschin, Mark; Lightstone, Alexander; Beachey, David; Wronski, Matt; Babic, Steven; Yeboah, Collins; Lee, Young; Soliman, Hany; Sahgal, Arjun

    2015-10-01

    The purpose of this communication is to inform the radiosurgery community of quality assurance (QA) results requiring attention in a commercial FDA-approved linac-based cone stereo-tactic radiosurgery (SRS) system. Standard published QA guidelines as per the American Association of Physics in Medicine (AAPM) were followed during the SRS system's commissioning process including end-to-end testing, cone concentricity testing, image transfer verification, and documentation. Several software and hardware deficiencies that were deemed risky were uncovered during the process and QA processes were put in place to mitigate these risks during clinical practice. In particular, the present work focuses on daily cone concentricity testing and commissioning-related findings associated with the software. Cone concentricity/alignment is measured daily using both optical light field inspection, as well as quantitative radiation field tests with the electronic portal imager. In 10 out of 36 clini-cal treatments, adjustments to the cone position had to be made to align the cone with the collimator axis to less than 0.5 mm and on two occasions the pre-adjustment measured offset was 1.0 mm. Software-related errors discovered during commissioning included incorrect transfer of the isocentre in DICOM coordinates, improper handling of non-axial image sets, and complex handling of beam data, especially for multi-target treatments. QA processes were established to mitigate the occurrence of the software errors. With proper QA processes, the reported SRS system complies with tolerances set out in established guidelines. Discussions with the vendor are ongoing to address some of the hardware issues related to cone alignment. © The Author(s) 2014.

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

    International Nuclear Information System (INIS)

    Rüegsegger, Michael B.; Steiner, Patrick; Kowal, Jens H.; Geiser, Dominik; Pica, Alessia; Aebersold, Daniel M.

    2014-01-01

    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

  1. Procedure for field axes measurement, beam indication adjustment, and figure of convergence determination within performance tests for radiation therapy equipment

    Energy Technology Data Exchange (ETDEWEB)

    Quast, U; Krause, K; Rassow, J [Essen Univ. (Gesamthochschule) (Germany, F.R.). Abt. fuer Klinische Strahlenphysik

    1976-09-01

    A routine measuring procedure for the verification of radiation field axes and figure of convergence within a spatial resolution of +- 0.5 mm is described. Measurements are done in two parallel planes in a certain distance before and behind the presumed isocentre. The used test arrangement permits rapid check and controlled adjustment of the alignment of beam or isocentre indicating devices for all isocentric radiation therapy equipment.

  2. Contribution of the deep-inspiration breath-hold technique in patients treated for a left breast cancer by mono-isocentric conformational irradiation; Apport du blocage inspiratoire profond chez des patientes traitees pour un cancer du sein gauche par irradiation conformationnelle mono-isocentrique

    Energy Technology Data Exchange (ETDEWEB)

    Zioueche, A.; Mege, A.; Bodez, V.; Rauglaudre, G. de [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at assessing the benefit of a deep-inspiration-breath-hold on heart sparing in 31 women treated in the left breast or wall and locoregional ganglionary areas by three-dimensional conformational irradiation with field-in-field optimization. All heart and lung parameters (delivered doses) have been significantly improved by a deep-inspiration-breath-hold. Short communication

  3. Dosimetric comparison of standard bi-dimensional radiotherapy, mono-isocentric three-dimensional and arc-therapy for a bilateral breast cancer case with ganglionary attack; Comparaison dosimetrique pour un cas de cancer du sein bilateral avec atteinte ganglionnaire de la radiotherapie bidimensionnelle standard, la radiotherapie tridimensionnelle mono-isocentrique et l'arctherapie

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, A. [Centre Leon-Berard, Lyon (France); Bodez, V.; Alric, K.; Chastel, D.; Mege, A. [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at determining the optimal radiotherapy technique for a patient operated from a bilateral breast cancer with ganglionary attack and peculiar thoracic conformation. A dosimetric study has been performed. Target volumes and lung and heart coverages have been compared for three techniques: bi-dimensional and three-dimensional radiotherapy, and arc-therapy. It appears that arc-therapy would allow a dosimetric and therapeutic duration gain without improving the target volume coverage while increasing doses delivered to organs at risk. Short communication

  4. 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.

  5. A treatment planning comparison of two different 3D conformal techniques for irradiation of head and neck cancer patients

    International Nuclear Information System (INIS)

    Krstevska, Valentina; Lukarski, Dusko; Petkovska, Sonja

    2010-01-01

    The purpose of this treatment planning study was to compare two different three dimensional conformal irradiation techniques for head and neck cancer patients. For 33 patients with head and neck carcinoma, irradiated according to the classical technique, we computed and evaluated a second irradiation technique in order to optimize the treatment planning protocol. The classical technique, termed 'electron-photon fields', employed two lateral semi-fields (23 fractions) for irradiation of the upper part of the planning target volume that should receive 50 Gy (PTV50) and an anterior and posterior field for the lower part. After the 23rd fraction the lateral fields were reduced from the dorsal side (2 fractions), in order to exclude the spinal cord from them. At the same time the dose to the shielded part of the target volume was delivered with matched electron fields. Finally, after the 25th fraction, the high risk volume was irradiated to the desired dose with plan where the spinal cord was completely shielded. In the new technique, termed 'oblique photon fields', 4 oblique isocentric photon fields were used (25 fractions): two anterior fields that covered the entire target volume that should receive 50 Gy and two posterior fields that covered only half of the target volume in order to shield the spinal cord. Thus, the necessity for using electron fields is eliminated. We kept the plan for irradiation of the high risk planning target volume the same as in the classical technique. The prescribed dose per fraction in all plans was 2 Gy. In both techniques the plans were optimized to the same maximal point dose and the same dose to the spinal cord. The oblique fields plan showed better coverage and homogeneity of the PTV50, except for the patients with positive resection margins receiving postoperative radiotherapy (receiving 66 Gy), where the coverage did not differ significantly. The conformity in both techniques did not differ significantly. The mean dose to the

  6. Free Electron Lasers 1998. Proceedings of the Twentieth International Free Electron Laser Conference Held in Williamsburg, Virginia, USA, on August 16-21, 1998

    National Research Council Canada - National Science Library

    Neil, G

    1999-01-01

    .... Sessions highlighting research in the following topics were: New Lasing, FEL Theory, SASE FELs, Accelerator Technology, FEL Technology, Linac-Based FELS, Storage-Ring-Based FELs, UV and X-ray Sources, and New Concepts...

  7. Electro- and photonuclear physics at intermediate energies: Saclay activities since 1970 and future prospects

    International Nuclear Information System (INIS)

    Schuhl, C.

    1981-06-01

    A review of experiments performed at the 600 MeV electron linear accelerator with electron, photon, pion and muon beams is reported and it is shown the long range perspective of nuclear physics in that domain

  8. To the calculation of energy resolution of ionization calorimeter

    International Nuclear Information System (INIS)

    Uchajkin, V.V.; Lagutin, A.A.

    1976-01-01

    The question of energy resolution of the ionization calorimeter is considered analytically. A method is discussed for calculating the probability characteristics (mean value and dispersion) of energy losses of an electron-photon shower by ionization in the calorimeter volume

  9. Seminar on gamma-gamma physics

    International Nuclear Information System (INIS)

    1984-04-01

    The following subjects have been studied in this seminar: photon pair production, hard scattering processes in photon-photon and electron-photon collisions, radiative corrections, final state interactions

  10. Overview of the Defense Programs Research and Technology Development Program for Fiscal Year 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-30

    This documents presents a programmatic overview and program element plan summaries for conceptual design and assessment; physics; computation and modeling; system engineering science and technology; electronics, photonics, sensors, and mechanical components; chemistry and materials; special nuclear materials, tritium, and explosives.

  11. Research in elementary particle physics: Technical progress report, June 1, 1987-May 31, 1988

    International Nuclear Information System (INIS)

    Kirsch, L.E.; Schnitzer, H.J.; Abbott, L.F.; Bensinger, J.R.; Blocker, C.A.

    1988-01-01

    The main topics discussed in the progress report: electron/photon algorithm groups; W and Z analysis; heavy quark analysis; gas gain monitoring; database upgrade; CDF test beam studies; string theory; cosmology; and neutral networks

  12. Antiaromatic bisindeno-[n]thienoacenes with small singlet biradical characters: Syntheses, structures and chain length dependent physical properties

    KAUST Repository

    Shi, Xueliang; Burrezo, Paula Mayorga; Lee, Sangsu; Zhang, Wenhua; Zheng, Bin; Dai, Gaole; Chang, Jingjing; Lõ pez Navarrete, Juan Teodomiro; Huang, Kuo-Wei; Kim, Dongho; Casado, Juan; Chi, Chunyan

    2014-01-01

    showing promising applications for organic electronics, photonics and spintronics. In this work, we designed and synthesized a new type of hybrid system, the so-called bisindeno-[n]thienoacenes (n = 1-4), by annulation of quinoidal fused α

  13. Solution of the electromagnetic cascade shower problem by analog Monte Carlo methods-EGS

    CERN Document Server

    Nelson, W R

    1980-01-01

    The development of the Electron-Gamma shower code system (EGS) is outlined and in its current form the author considers that there is now available a means of simulating almost any electron-photon transport problem. (20 refs).

  14. Photon-Electron Interaction and Condense Beams

    International Nuclear Information System (INIS)

    Chattopadhyay, S.

    1998-01-01

    We discuss beams of charged particles and radiation from multiple perspectives. These include fundamental acceleration and radiation mechanisms, underlying electron-photon interaction, various classical and quantum phase-space concepts and fluctuational interpretations

  15. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Research Center for Electron-Photon Science, Tohoku University, 1-2-1 ... nuclei precisely determined by elastic scattering [1]. .... In order to fulfill these requirements, a window-frame shaped dipole magnet with a gap.

  16. Progress in electronics and photonics with nanomaterials

    DEFF Research Database (Denmark)

    Mishra, Yogendra Kumar; Murugan, Arul; Kotakoski, Jani

    2017-01-01

    Nanomaterials have been at the center of attraction for almost five decades as their contributions to different disciplines such as electronics, photonics and medicine are enormous. Various kinds of nanomaterials have been developed and are currently utilized in innumerable applications. Neverthe......Nanomaterials have been at the center of attraction for almost five decades as their contributions to different disciplines such as electronics, photonics and medicine are enormous. Various kinds of nanomaterials have been developed and are currently utilized in innumerable applications...

  17. An anthropomorphic phantom study of visualisation of surgical clips for partial breast irradiation (PBI) setup verification

    International Nuclear Information System (INIS)

    Thomas, Carys W.; Nichol, Alan M.; Park, Julie E.; Hui, Jason F.; Giddings, Alison A.; Grahame, Sheri; Otto, Karl

    2009-01-01

    Surgical clips were investigated for partial breast image-guided radiotherapy (IGRT). Small titanium clips were insufficiently well visualised. Medium tantalum clips were best for megavoltage IGRT and small tantalum clips were best for floor mounted kilovoltage IGRT (ExacTrac TM ). Both small tantalum and medium titanium clips were suitable for isocentric kilovoltage IGRT

  18. General-purpose radiological examination device

    Energy Technology Data Exchange (ETDEWEB)

    Slaby, J

    1978-03-15

    Equipment is described suitable for all radiological examinations using x-ray and neuroradiological diagnostic machines. The equipment consists of a gimbal suspension supporting a base plate and an imaging system, a gantry on which a neurological seat is pivoted capable of isocentrically positioning the patient's head.

  19. Pitch dependence of longitudinal sampling and aliasing effects in multi-slice helical computed tomography (CT)

    International Nuclear Information System (INIS)

    La Riviere, Patrick J.; Pan Xiaochuan

    2002-01-01

    In this work, we investigate longitudinal sampling and aliasing effects in multi-slice helical CT. We demonstrate that longitudinal aliasing can be a significant, complicated, and potentially detrimental effect in multi-slice helical CT reconstructions. Multi-slice helical CT scans are generally undersampled longitudinally for all pitches of clinical interest, and the resulting aliasing effects are spatially variant. As in the single-slice case, aliasing is shown to be negligible at the isocentre for circularly symmetric objects due to a fortuitous aliasing cancellation phenomenon. However, away from the isocentre, aliasing effects can be significant, spatially variant, and highly pitch dependent. This implies that measures more sophisticated than isocentre slice sensitivity profiles are needed to characterize longitudinal properties of multi-slice helical CT systems. Such measures are particularly important in assessing the question of whether there are preferred pitches in helical CT. Previous analyses have generally focused only on isocentre sampling patterns, and our more global analysis leads to somewhat different conclusions than have been reached before, suggesting that pitches 3, 4, 5, and 6 are favourable, and that half-integer pitches are somewhat suboptimal. (author)

  20. Determination and evaluation of intra fractional and set-up changes during radiotherapy to the cervical carcinoma using cone beam computed tomography

    International Nuclear Information System (INIS)

    Pathak, Pankaj; Kumar, Rajesh; Birbiya, Narendra; Mishra, Praveen Kumar; Singh, Manisha; Mishra, Pankaj Kumar

    2017-01-01

    To confirm the accuracy of the location of the Fudicial markings in relation to the actual isocentre of the irradiated volume due to Intra-fractional and Set-Up changes in Cancer Cervix with the help of Cone Beam computed Tomography (CBCT)

  1. An anthropomorphic phantom study of visualisation of surgical clips for partial breast irradiation (PBI) setup verification.

    Science.gov (United States)

    Thomas, Carys W; Nichol, Alan M; Park, Julie E; Hui, Jason F; Giddings, Alison A; Grahame, Sheri; Otto, Karl

    2009-01-01

    Surgical clips were investigated for partial breast image-guided radiotherapy (IGRT). Small titanium clips were insufficiently well visualised. Medium tantalum clips were best for megavoltage IGRT and small tantalum clips were best for floor mounted kilovoltage IGRT (ExacTrac). Both small tantalum and medium titanium clips were suitable for isocentric kilovoltage IGRT.

  2. The radiation isocenter verification using an electronic system of image portal; Verificacion del isocentro de radiacion utilizando un sistema electronico de imagen portal

    Energy Technology Data Exchange (ETDEWEB)

    Merino Gestoso, J. A.; Portas Ferradas, B. C.; Rosa Menendez, P.; Chapel Gomez, M. L.; Fernandez Cerezo, S.; Vazquez Varela, P.

    2013-07-01

    In this paper we present a procedure optimized for verification the isocenter of radiation with respect to the rotation of the gantry and the turn isocentric table of two accelerators SIEMENS, ONCOR and ARTISTE with a mannequin developed in our service and analyzing the images acquired with the EPID from each of the teams. (Author)

  3. SU-G-TeP4-12: Individual Beam QA for a Robotic Radiosurgery System Using a Scintillator Cone

    Energy Technology Data Exchange (ETDEWEB)

    McGuinness, C; Descovich, M; Sudhyadhom, A [University of California San Francisco, San Francisco, CA (United States)

    2016-06-15

    Purpose: The targeting accuracy of the Cyberknife system is measured by end-to-end tests delivering multiple isocentric beams to a point in space. While the targeting accuracy of two representative beams can be determined by a Winston-Lutz-type test, no test is available today to determine the targeting accuracy of each clinical beam. We used a scintillator cone to measure the accuracy of each individual beam. Methods: The XRV-124 from Logos Systems Int’l is a scintillator cone with an imaging system that is able to measure individual beam vectors and a resulting error between planned and measured beam coordinates. We measured the targeting accuracy of isocentric and non-isocentric beams for a number of test cases using the Iris and the fixed collimator. The average difference between plan and measured beam position was 0.8–1.2mm across the collimator sizes and plans considered here. The max error for a single beam was 2.5mm for the isocentric plans, and 1.67mm for the non-isocentric plans. The standard deviation of the differences was 0.5mm or less. Conclusion: The CyberKnife System is specified to have an overall targeting accuracy for static targets of less than 0.95mm. In E2E tests using the XRV124 system we measure average beam accuracy between 0.8 to 1.23mm, with maximum of 2.5mm. We plan to investigate correlations between beam position error and robot position, and to quantify the effect of beam position errors on patient specific plans. Martina Descovich has received research support and speaker honoraria from Accuray.

  4. SU-G-TeP4-12: Individual Beam QA for a Robotic Radiosurgery System Using a Scintillator Cone

    International Nuclear Information System (INIS)

    McGuinness, C; Descovich, M; Sudhyadhom, A

    2016-01-01

    Purpose: The targeting accuracy of the Cyberknife system is measured by end-to-end tests delivering multiple isocentric beams to a point in space. While the targeting accuracy of two representative beams can be determined by a Winston-Lutz-type test, no test is available today to determine the targeting accuracy of each clinical beam. We used a scintillator cone to measure the accuracy of each individual beam. Methods: The XRV-124 from Logos Systems Int’l is a scintillator cone with an imaging system that is able to measure individual beam vectors and a resulting error between planned and measured beam coordinates. We measured the targeting accuracy of isocentric and non-isocentric beams for a number of test cases using the Iris and the fixed collimator. The average difference between plan and measured beam position was 0.8–1.2mm across the collimator sizes and plans considered here. The max error for a single beam was 2.5mm for the isocentric plans, and 1.67mm for the non-isocentric plans. The standard deviation of the differences was 0.5mm or less. Conclusion: The CyberKnife System is specified to have an overall targeting accuracy for static targets of less than 0.95mm. In E2E tests using the XRV124 system we measure average beam accuracy between 0.8 to 1.23mm, with maximum of 2.5mm. We plan to investigate correlations between beam position error and robot position, and to quantify the effect of beam position errors on patient specific plans. Martina Descovich has received research support and speaker honoraria from Accuray

  5. Electron and photon-beam induced reactions of adsorbed disilane: Low-temperature thin-film growth

    International Nuclear Information System (INIS)

    Bozso, F.; Avouris, Ph.

    1991-01-01

    Electrons and photons of sufficient energy can cause fragmentation and desorption of adsorbed molecules or fragments of them, by inducing electronic excitations to dissociative states. The surface species after such excitations are mostly of highly reactive radical character, which readily react with the substrate and with other molecular or radical species in the adsorbed layer. This paper discusses the adsorption, thermal and electron/photon-beam induced reactions of disilane, oxygen and ammonia on Si(111)-7x7, and the electron/photon-induced growth of silicon, silicon dioxide and silicon nitride films at 100K

  6. Stereotactic treatment. Definitions and literature overview

    International Nuclear Information System (INIS)

    Fontenla, D.P.

    2008-01-01

    The topics discussed include, among others, the following: Radiosurgery definitions; Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT); Available uncertainties in SRS; Gamma knife; Linac-based SRS; Components of a radiosurgery system; Stereotactic hardware (brain lab); m3 linac attachment; Radiosurgery - clinical procedure; Cancer management; Rationale for SRT; Role of radiosurgery in the management of intracranial tumors; Indications for stereotactic SRS/SRT; Physical components required for SRS/SRT; Stereotactic patient set-up; Stereotactic CT scan for SRS; Physical components required for SRT: Relocatable head frame (GTC); Patient immobilization; Treatment planning system; Basic requirements for SRS dosimetry (Linac based); Stereotactic set-up QA (Linac); Stereotactic frames and QA; Beam dose measurements; Dose evaluation tools; Phantoms. (P.A.)

  7. Potential use of superconducting magnets for neutron therapy

    Energy Technology Data Exchange (ETDEWEB)

    Duthil, R; Kircher, F; Lottin, J C; Palanque, S [CEA/Saclay, 91 - Gif-sur-Yvette (France); Aucouturier, J; Fache, P [DT, CGR MeV, 78 Buc (France)

    1984-01-01

    The results of a feasibility study on the use of superconducting magnets for neutron therapy devices will be reported. Two possibilities can be foreseen: - SC magnets used in the isocentric primary beam transport line. The advantage is to increase the energy of the particles which can be transported (up to 70 MeV for protons), compared to existing systems, with a lower weight. This solution could be used very quickly. - A SC isocentric cyclotron, working at on average field of 4.7 T for accelerating deuterons up to 30 MeV. The feasibility of such a machine is fairly established but technical developments are needed, mainly in view of the rotation and of the miniaturisation of the cyclotron.

  8. Selection of the optimal radiotherapy technique for locally advanced hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Lee, Ik-Jae; Seong, Jinsil; Koom, Woong-Sub; Kim, Yong-Bae; Jeon, Byeong-Chul; Kim, Joo-Ho; Han, Kwang-Hyub

    2011-01-01

    Various techniques are available for radiotherapy of hepatocellular carcinoma, including three-dimensional conformal radiotherapy, linac-based intensity-modulated radiotherapy and helical tomotherapy. The purpose of this study was to determine the optimal radiotherapy technique for hepatocellular carcinoma. Between 2006 and 2007, 12 patients underwent helical tomotherapy for locally advanced hepatocellular carcinoma. Helical tomotherapy computerized radiotherapy planning was compared with the best computerized radiotherapy planning for three-dimensional conformal radiotherapy and linac-based intensity-modulated radiotherapy for the delivery of 60 Gy in 30 fractions. Tumor coverage was assessed by conformity index, radical dose homogeneity index and moderated dose homogeneity index. Computerized radiotherapy planning was also compared according to the tumor location. Tumor coverage was shown to be significantly superior with helical tomotherapy as assessed by conformity index and moderated dose homogeneity index (P=0.002 and 0.03, respectively). Helical tomotherapy showed significantly lower irradiated liver volume at 40, 50 and 60 Gy (V40, V50 and V60, P=0.04, 0.03 and 0.01, respectively). On the contrary, the dose-volume of three-dimensional conformal radiotherapy at V20 was significantly smaller than those of linac-based intensity-modulated radiotherapy and helical tomotherapy in the remaining liver (P=0.03). Linac-based intensity-modulated radiotherapy showed better sparing of the stomach compared with helical tomotherapy in the case of separated lesions in both lobes (12.3 vs. 24.6 Gy). Helical tomotherapy showed the high dose-volume exposure to the left kidney due to helical delivery in the right lobe lesion. Helical tomotherapy achieved the best tumor coverage of the remaining normal liver. However, helical tomotherapy showed much exposure to the remaining liver at the lower dose region and left kidney. (author)

  9. Dosimetric feasibility of magnetic resonance imaging-guided tri-cobalt 60 preoperative intensity modulated radiation therapy for soft tissue sarcomas of the extremity.

    Science.gov (United States)

    Kishan, Amar U; Cao, Minsong; Mikaeilian, Argin G; Low, Daniel A; Kupelian, Patrick A; Steinberg, Michael L; Kamrava, Mitchell

    2015-01-01

    The purpose of this study was to investigate the dosimetric differences of delivering preoperative intensity modulated radiation therapy (IMRT) to patients with soft tissue sarcomas of the extremity (ESTS) with a teletherapy system equipped with 3 rotating (60)Co sources and a built-in magnetic resonance imaging and with standard linear accelerator (LINAC)-based IMRT. The primary study population consisted of 9 patients treated with preoperative radiation for ESTS between 2008 and 2014 with LINAC-based static field IMRT. LINAC plans were designed to deliver 50 Gy in 25 fractions to 95% of the planning target volume (PTV). Tri-(60)Co system IMRT plans were designed with ViewRay system software. Tri-(60)Co-based IMRT plans achieved equivalent target coverage and dosimetry for organs at risk (long bone, skin, and skin corridor) compared with LINAC-based IMRT plans. The maximum and minimum PTV doses, heterogeneity indices, and ratio of the dose to 50% of the volume were equivalent for both planning systems. One LINAC plan violated the maximum bone dose constraint, whereas none of the tri-(60)Co plans did. Using a tri-(60)Co system, we were able to achieve equivalent dosimetry to the PTV and organs at risk for patients with ESTS compared with LINAC-based IMRT plans. The tri-(60)Co system may be advantageous over current treatment platforms by allowing PTV reduction and by elimination of the additional radiation dose associated with daily image guidance, but this needs to be evaluated prospectively. Copyright © 2015 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  10. Volume Changes After Stereotactic LINAC Radiotherapy in Vestibular Schwannoma: Control Rate and Growth Patterns

    International Nuclear Information System (INIS)

    Langenberg, Rick van de; Dohmen, Amy J.C.; Bondt, Bert J. de; Nelemans, Patty J.; Baumert, Brigitta G.; Stokroos, Robert J.

    2012-01-01

    Purpose: The purpose of this study was to evaluate the control rate of vestibular schwannomas (VS) after treatment with linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) or radiotherapy (SRT) by using a validated volumetric measuring tool. Volume-based studies on prognosis after LINAC-based SRS or SRT for VS are reported scarcely. In addition, growth patterns and risk factors predicting treatment failure were analyzed. Materials and Methods: Retrospectively, 37 VS patients treated with LINAC based SRS or SRT were analyzed. Baseline and follow-up magnetic resonance imaging scans were analyzed with volume measurements on contrast enhanced T1-weighted magnetic resonance imaging. Absence of intervention after radiotherapy was defined as “no additional intervention group, ” absence of radiological growth was defined as “radiological control group. ” Significant growth was defined as a volume change of 19.7% or more, as calculated in a previous study. Results: The cumulative 4-year probability of no additional intervention was 96.4% ± 0.03; the 4-year radiological control probability was 85.4% ± 0.1). The median follow-up was 40 months. Overall, shrinkage was seen in 65%, stable VS in 22%, and growth in 13%. In 54% of all patients, transient swelling was observed. No prognostic factors were found regarding VS growth. Previous treatment and SRS were associated with transient swelling significantly. Conclusions: Good control rates are reported for LINAC based SRS or SRT in VS, in which the lower rate of radiological growth control is attributed to the use of the more sensitive volume measurements. Transient swelling after radiosurgery is a common phenomenon and should not be mistaken for treatment failure. Previous treatment and SRS were significantly associated with transient swelling.

  11. Radiosurgery for cerebral arteriovenous malformation during pregnancy: A case report focusing on fetal exposure to radiation

    OpenAIRE

    Nagayama, Kazuki; Kurita, Hiroki; Tonari, Ayako; Takayama, Makoto; Shiokawa, Yoshiaki

    2010-01-01

    Introduction: We present the case of a pregnant woman who underwent linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) and we discuss the fetal exposure to radiation. Clinical Presentation: A 20-year-old woman at 18 weeks of gestation presented with right cerebral hemorrhage and underwent urgent evacuation of the hematoma. She recovered well after surgery, but cerebral angiography after the surgery revealed a small deeply seated arteriovenous malformation (AVM) in the right fron...

  12. "Riesenrad" Ion Gantry for Hadron Therapy, 3

    OpenAIRE

    Benedikt, Michael; Bryant, P J; Holy, P; Pullia, M

    1999-01-01

    When using accelerator beams for cancer therapy, the three-dimensional freedom afforded by a gantry helps the treatment planner to spread out surface doses, avoid directions that intercept vital organs and irradiate a volume that is conformal with the tumour. The general preference is for an iso-centric gantry turning 360° in the vertical plane around the patient bed with sufficient space to be able to orientate the patient through 360° in the horizontal plane. For hadrontherapy, gantries are...

  13. An ill-conditioning conformal radiotherapy analysis based on singular values decomposition

    International Nuclear Information System (INIS)

    Lefkopoulos, D.; Grandjean, P.; Bendada, S.; Dominique, C.; Platoni, K.; Schlienger, M.

    1995-01-01

    Clinical experience in stereotactic radiotherapy of irregular complex lesions had shown that optimization algorithms were necessary to improve the dose distribution. We have developed a general optimization procedure which can be applied to different conformal irradiation techniques. In this presentation this procedure is tested on the stereotactic radiotherapy modality of complex cerebral lesions treated with multi-isocentric technique based on the 'associated targets methodology'. In this inverse procedure we use the singular value decomposition (SVD) analysis which proposes several optimal solutions for the narrow beams weights of each isocentre. The SVD analysis quantifies the ill-conditioning of the dosimetric calculation of the stereotactic irradiation, using the condition number which is the ratio of the bigger to smaller singular values. Our dose distribution optimization approach consists on the study of the irradiation parameters influence on the stereotactic radiotherapy inverse problem. The adjustment of the different irradiation parameters into the 'SVD optimizer' procedure is realized taking into account the ratio of the quality reconstruction to the time calculation. It will permit a more efficient use of the 'SVD optimizer' in clinical applications for real 3D lesions. The evaluation criteria for the choice of satisfactory solutions are based on the dose-volume histograms and clinical considerations. We will present the efficiency of ''SVD optimizer'' to analyze and predict the ill-conditioning in stereotactic radiotherapy and to recognize the topography of the different beams in order to create optimal reconstructed weighting vector. The planification of stereotactic treatments using the ''SVD optimizer'' is examined for mono-isocentrically and complex dual-isocentrically treated lesions. The application of the SVD optimization technique provides conformal dose distribution for complex intracranial lesions. It is a general optimization procedure

  14. Comparison between In-house developed and Diamond commercial software for patient specific independent monitor unit calculation and verification with heterogeneity corrections.

    Science.gov (United States)

    Kuppusamy, Vijayalakshmi; Nagarajan, Vivekanandan; Jeevanandam, Prakash; Murugan, Lavanya

    2016-02-01

    The study was aimed to compare two different monitor unit (MU) or dose verification software in volumetric modulated arc therapy (VMAT) using modified Clarkson's integration technique for 6 MV photons beams. In-house Excel Spreadsheet based monitor unit verification calculation (MUVC) program and PTW's DIAMOND secondary check software (SCS), version-6 were used as a secondary check to verify the monitor unit (MU) or dose calculated by treatment planning system (TPS). In this study 180 patients were grouped into 61 head and neck, 39 thorax and 80 pelvic sites. Verification plans are created using PTW OCTAVIUS-4D phantom and also measured using 729 detector chamber and array with isocentre as the suitable point of measurement for each field. In the analysis of 154 clinically approved VMAT plans with isocentre at a region above -350 HU, using heterogeneity corrections, In-house Spreadsheet based MUVC program and Diamond SCS showed good agreement TPS. The overall percentage average deviations for all sites were (-0.93% + 1.59%) and (1.37% + 2.72%) for In-house Excel Spreadsheet based MUVC program and Diamond SCS respectively. For 26 clinically approved VMAT plans with isocentre at a region below -350 HU showed higher variations for both In-house Spreadsheet based MUVC program and Diamond SCS. It can be concluded that for patient specific quality assurance (QA), the In-house Excel Spreadsheet based MUVC program and Diamond SCS can be used as a simple and fast accompanying to measurement based verification for plans with isocentre at a region above -350 HU. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. Proton spectroscopic imaging of polyacrylamide gel dosimeters for absolute radiation dosimetry

    International Nuclear Information System (INIS)

    Murphy, P.S.; Schwarz, A.J.; Leach, M.O.

    2000-01-01

    Proton spectroscopy has been evaluated as a method for quantifying radiation induced changes in polyacrylamide gel dosimeters. A calibration was first performed using BANG-type gel samples receiving uniform doses of 6 MV photons from 0 to 9 Gy in 1 Gy intervals. The peak integral of the acrylic protons belonging to acrylamide and methylenebisacrylamide normalized to the water signal was plotted against absorbed dose. Response was approximately linear within the range 0-7 Gy. A large gel phantom irradiated with three, coplanar 3x3cm square fields to 5.74 Gy at isocentre was then imaged with an echo-filter technique to map the distribution of monomers directly. The image, normalized to the water signal, was converted into an absolute dose map. At the isocentre the measured dose was 5.69 Gy (SD = 0.09) which was in good agreement with the planned dose. The measured dose distribution elsewhere in the sample shows greater errors. A T 2 derived dose map demonstrated a better relative distribution but gave an overestimate of the dose at isocentre of 18%. The data indicate that MR measurements of monomer concentration can complement T 2 -based measurements and can be used to verify absolute dose. Compared with the more usual T 2 measurements for assessing gel polymerization, monomer concentration analysis is less sensitive to parameters such as gel pH and temperature, which can cause ambiguous relaxation time measurements and erroneous absolute dose calculations. (author)

  16. Multicentre dosimetric comparison of photon-junctioning techniques in head and neck radiotherapy

    International Nuclear Information System (INIS)

    Kron, T.

    2003-01-01

    Because many head and neck radiotherapy treatment techniques rely on a junction between X-ray fields, it was the aim of the present study to investigate the use of different junctioning techniques and the affect on the dose across the junction. Techniques in use at nine radiotherapy centres in Australia were investigated using thermoluminescence dosimetry (TLD). The techniques could broadly be divided into two groups: (i) use of the light field to match the fields after moving the patient; and (ii) use of asymmetric collimation to create a single isocentre located in the junction. The mean dose at the junction and its reproducibility was studied in five consecutive treatments in each centre using 25 TLD chips placed throughout the junction in an anthropomorphic phantom. There was a tendency for the mono-isocentric technique to deliver a lower, more accurate mean dose at the junction (Group I: 1.22 Gy (n = 8) vs Group II: 0.96 Gy (n = 5) for 1 Gy planned, some centres contributed to both technique) with greater reproducibility (Group I: 9.6%, Group II: 5.1 % of the mean dose). We conclude that a mono-isocentric treatment technique has the potential to deliver a more accurate and reproducible dose distribution at the field junction of photon beams in head and neck treatment. Copyright (2003) Blackwell Science Pty Ltd

  17. Measurement for the MLC leaf velocity profile by considering the leaf leakage using a radiographic film

    International Nuclear Information System (INIS)

    Chow, James C L; Grigorov, Grigor N

    2006-01-01

    A method to measure the velocity profile of a multi-leaf collimator (MLC) leaf along its travel range using a radiographic film is reported by considering the intra-leaf leakage. A specific dynamic MLC field with leaves travelling from the field edge to the isocentre line was designed. The field was used to expose a radiographic film, which was then scanned, and the dose profile along the horizontal leaf axis was measured. The velocity at a sampling point on the film can be calculated by considering the horizontal distance between the sampling point and the isocentre line, dose at the sampling point, dose rate of the linear accelerator, the total leaf travel time from the field edge to isocentre line and the pre-measured dose rate of leaf leakage. With the leaf velocities and velocity profiles for all MLC leaves measured routinely, a comprehensive and simple QA for the MLC can be set up to test the consistency of the leaf velocity performance which is essential to the IMRT delivery using a sliding window technique. (note)

  18. Abdominal CT during pregnancy: a phantom study on the effect of patient centring on conceptus radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Solomou, G.; Damilakis, J. [University of Crete, Faculty of Medicine, Department of Medical Physics, Heraklion, P.O. Box 2208, Crete (Greece); Papadakis, A.E. [University Hospital of Heraklion, Department of Medical Physics, Heraklion, P.O. Box 1352, Crete (Greece)

    2015-04-01

    To investigate the effect of patient centring on conceptus radiation dose and image quality in abdominal CT during pregnancy. Three anthropomorphic phantoms that represent a pregnant woman at the three trimesters of gestation were subjected to a routine abdominal CT. Examinations were performed with fixed mAs (mAs{sub f}) and with the automatic exposure control system (AEC) activated. The percent reduction between mAs{sub f} and modulated mAs (mAs{sub mod}) was calculated. Conceptus dose (D{sub c}) was measured using thermoluminescent dosimeters. To study the effect of misplacement of pregnant women on D{sub c}, each phantom was positioned at various locations relative to gantry isocentre. Image quality was evaluated on the basis of image noise, signal-to-noise ratio, and contrast-to-noise ratio. The maximum reduction between mAs{sub f} and mAs{sub mod} was 59.8 %, while the corresponding D{sub C} reduction was 59.3 %. D{sub C} was found to decrease by up to 25 % and 7.9 % for phantom locations below and above the isocentre, respectively. Image quality deteriorated when AEC was activated, and it was progressively improved from lower to higher than the isocentre locations. Centring errors do not result in an increase in D{sub c}. To maintain image quality, accurate centring is required. (orig.)

  19. A quality assurance program of simulators in radiotherapy. Pt. 2. Extent and results of long-term quality assurance tests on a therapy simulator

    International Nuclear Information System (INIS)

    Mueller-Sievers, K.; Kober, B.

    1997-01-01

    Background: Since 1990 we follow a quality assurance program with periodical tests of functional performance values of a 16-year-old simulator. Material and Method: For this purpose we adopted and modified German standards for quality assurance on linear accelerators and international standards elaborated for simulators (International Electrotechnical Commission). The tests are subdivided into daily visual checks (light field indication, optical distance indicator, isocentre-indicating devices, indication of gantry and collimator angles) and monthly and annually tests of relevant simulator parameters. Some important examples demonstrate the small variation of parameters over 6 years: Position of the light field centre when rotating the collimator, diameter of the isocentre circle when rotating the gantry, accuracy of the isocentre indication device, and coincidence of light field and simulated radiation field. Results: As an important result we can state, that by these rigid periodic tests it was possible to detect and compensate deteriorations of simulators quality rapidly. Conclusions: Technical improvements and specific calling-in of maintenance personnel whenever felt appropriate provided performance characteristics of our old simulator which are required by international recommendations as a basis for modern radiotherapy. (orig.) [de

  20. An augmented space formulation of the optical conductivity of random semiconducting alloys

    International Nuclear Information System (INIS)

    Mookerjee, A.

    1984-08-01

    A formalism has been developed for the study of optical conductivity of disordered semiconducting alloys effect of off-diagonal disorder, clustering and randomness in the electron-photon interaction matrix may be incorporated within this. The aim is to finally study GaAssub(x)Sbsub(1-x) as well as deep levels in this alloy. (author)

  1. Quantum processes in an intense electromagnetic field

    International Nuclear Information System (INIS)

    Gitman, D.M.

    1976-01-01

    An approach is proposed to the consideration of processes in an external electromagnetic field which produces real pairs. Interaction with the field is taken into account precisely with the aid of solutions of the Dirac's equation. Processes of arbitrary order with respect to electron-photon interaction are considered

  2. Spontaneous symmetry breakdown in gauge theories

    International Nuclear Information System (INIS)

    Scadron, M.D.

    1982-01-01

    The dynamical theory of spontaneous breakdown correctly predicts the bound states and relates the order parameters of electron-photon superconductivity and quark-gluon chiral symmetry. A similar statement cannot be made for the standard electro-weak gauge symmetry. (author)

  3. Research in elementary particle physics: Technical progress report, June 1, 1988--May 31, 1989

    International Nuclear Information System (INIS)

    Kirsch, L.E.; Schnitzer, H.J.; Abbott, L.F.; Bensinger, J.R.; Blocker, C.A.

    1989-01-01

    This paper discusses the following topics: electroweak decays; search for top decay into leptons; search for top decay into jets; electron photon algorithm group; jet momenta corrections; superconducting supercollider program; strings and conformal field theories; quantum gravity and wormholes; and neural networks

  4. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ... the presence of carbides. Volume 24 Issue 3 June 2001 pp 317-322 Cement and Concrete Materials. Characterization of ancient Indian iron and entrapped slag inclusions using electron, photon and nuclear microprobes ... 483-491 Alloys and Steels. Alloy design of ductile phosphoric iron: Ideas from archaeometallurgy.

  5. Environmental dose rate heterogeneity of beta radiation and its implications for luminescence dating: Monte Carlo modelling and experimental validation

    DEFF Research Database (Denmark)

    Nathan, R.P.; Thomas, P.J.; Jain, M.

    2003-01-01

    and identify the likely size of these effects on D-e distributions. The study employs the MCNP 4C Monte Carlo electron/photon transport model, supported by an experimental validation of the code in several case studies. We find good agreement between the experimental measurements and the Monte Carlo...

  6. Measurement of the Higgs boson mass from the H -> gamma gamma and H -> ZZ* -> 4l channels in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector

    Czech Academy of Sciences Publication Activity Database

    Aad, G.; Abbott, B.; Abdallah, J.; Böhm, Jan; Chudoba, Jiří; Havránek, Miroslav; Hejbal, Jiří; Jakoubek, Tomáš; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Lysák, Roman; Marčišovský, Michal; Mikeštíková, Marcela; Němeček, Stanislav; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Vrba, Václav

    2014-01-01

    Roč. 90, č. 5 (2014), "052004-1"-"052004-10" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LG13009 Institutional support: RVO:68378271 Keywords : Higgs particle * width * ATLAS * mass spectrum * CERN LHC Coll * calibration * CERN Lab * electron * photon Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.643, year: 2014

  7. On the transparency of the metagalaxy to ultrahigh-energy gamma rays

    International Nuclear Information System (INIS)

    Aharonyan, F.A.; Vardanyan, V.V.

    1987-01-01

    The electron-photon shower production in the field of the microwave background radiation (MBR) is considered. The absolute flux of ultrahigh-energy cascade gamma-rays (E>or approx.5X10 19 eV), resulting from the Π-meson photoproduction in the field of the MBR is obtained

  8. Tuning of InGaAsP planar photonic crystal nanocavities by local liquid crystal infiltration

    NARCIS (Netherlands)

    Kicken, H.H.J.E.

    2009-01-01

    Future data-processing will increasingly employ photonic circuits in addition to conventional electronics. Photonic crystals (PC), a periodic arrangement of dielectrics, can influence the flow of light on the smallest scale, i.e. at or below the optical wavelength. Therefore PCs are a necessary tool

  9. MIT Lincoln Laboratory Annual Report 2012

    Science.gov (United States)

    2012-01-01

    variety of “beyond silicon” pathways, including three-dimensional integration, mixed materials, electronic-photonic circuit integration, graphene ...and to spackle, prime, and paint walls. They also hung siding and installed doors and insulation. Community giving Members of the Hispanic and Latino

  10. Digital device for synchronous storage

    International Nuclear Information System (INIS)

    Kobzar', Yu.M.; Kovtun, V.G.; Pashechko, N.I.

    1991-01-01

    Synchronous storage digital device for IR electron-photon emission spectrometer operating with analogue-to-digital converter F4223 or monocrystal converter K572PV1 is described. The device accomplished deduction of noise-background in each storage cycle. Summation and deduction operational time equals 90 ns, device output code discharge - 20, number of storages -2 23

  11. 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.

    Science.gov (United States)

    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

    2016-01-01

    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-(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-(60)Co system for a prescription dose of 50Gy in 4 fractions. Doses to organs at risk were evaluated based on established MD Anderson constraints for central lung SBRT. R100 values were calculated as the total tissue volume receiving 100% of the dose (V100) divided by the planning target volume and compared to assess dose conformity. Dosimetric comparisons between LINAC-based and tri-(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 48.3cc (range: 12.1 to 139.4cc). Of the tri-(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). R100 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-(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-(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 improving normal tissue sparing, which warrants further

  12. SU-F-T-293: Experimental Comparisons of Ionization Chambers with Different Volumes for CyberKnife Delivery Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, M [Kobe Minimally invasive Cancer Center, Kobe, Hyogo (Japan); Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Munetomo, Y; Ogata, T; Uehara, K; Tsudou, S; Nishimura, H; Mayahara, H [Kobe Minimally invasive Cancer Center, Kobe, Hyogo (Japan); Sasaki, R [Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan)

    2016-06-15

    Purpose: To evaluate the practicality use of ionization chambers with different volumes for delivery quality assurance of CyberKnife plans, Methods: Dosimetric measurements with a spherical solid water phantom and three ionization chambers with volumes of 0.13, 0.04, and 0.01 cm3 (IBA CC13, CC04, and CC01, respectively) were performed for various CyberKnife clinical treatment plans including both isocentric and nonisocentric delivery. For each chamber, the ion recombination correction factors Ks were calculated using the Jaffe plot method and twovoltage method at a 10-cm depth for a 60-mm collimator field in a water phantom. The polarity correction factors Kpol were determined for 5–60-mm collimator fields in same experimental setup. The measured doses were compared to the doses for the detectors calculated using a treatment planning system. Results: The differences in the Ks between the Jaffe plot method and two-voltage method were −0.12, −0.02, and 0.89% for CC13, CC04, and CC01, respectively. The changes in Kpol for the different field sizes were 0.2, 0.3, and 0.8% for CC13, CC04, and CC01, respectively. The measured doses for CC04 and CC01 were within 3% of the calculated doses for the clinical treatment plans with isocentric delivery with collimator fields greater than 12.5 mm. Those for CC13 had differences of over 3% for the plans with isocentric delivery with collimator fields less than 15 mm. The differences for the isocentric plans were similar to those for the single beam plans. The measured doses for each chamber were within 3% of the calculated doses for the non-isocentric plans except for that with a PTV volume less than 1.0 cm{sup 3}. Conclusion: Although there are some limitations, the ionization chamber with a smaller volume is a better detector for verification of the CyberKnife plans owing to the high spatial resolution.

  13. TH-EF-BRB-03: Significant Cord and Esophagus Dose Reduction by 4π Non-Coplanar Spine Stereotactic Body Radiation Therapy and Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Yu, V; Tran, A; Nguyen, D; Woods, K; Cao, M; Kaprealian, T; Chin, R; Low, D; Sheng, K [UCLA, Los Angeles, CA (United States)

    2016-06-15

    Purpose: To demonstrate significant organ-at-risk (OAR) sparing achievable with 4π non-coplanar radiotherapy on spine SBRT and SRS patients. Methods: Twenty-five stereotactic spine cases previously treated with VMAT (n = 23) or IMRT (n = 2) were included in this study. A computer-aided-design model of a Linac with a 3D-scanned human surface was utilized to determine the feasible beam space throughout the 4π steradian and beam specific source-to-target-distances (STD) required for collision avoidance. 4π radiotherapy plans integrating beam orientation and fluence map optimization were then created using a column-generation algorithm. Twenty optimal beams were selected for each case. To evaluate the tradeoff between dosimetric benefit and treatment complexity, 4π plans including only isocentrically deliverable beams were also created. Beam angles of all standard and isocentric 4π plans were imported into Eclipse to recalculate the dose using the same calculation engine as the clinical plans for unbiased comparison. OAR and PTV dose statistics for the clinical, standard-4π, and isocentric-4π plans were compared. Results: Comparing standard-4π to clinical plans, particularly significant average percent reduction in the [mean, maximum] dose of the cord and esophagus of [41%, 21.7%], and [38.7%, 36.4%] was observed, along with global decrease in all other OAR dose statistics. The average cord volume receiving more than 50% prescription dose was substantially decreased by 76%. In addition, improved PTV coverage was demonstrated with a maximum dose reduction of 0.93% and 1.66% increase in homogeneity index (D95/D5). All isocentric-4π plans achieved dosimetric performance equivalent to that of the standard-4π plans with higher delivery complexity. Conclusion: 4π radiotherapy significantly improves stereotactic spine treatment dosimetry. With the substantial OAR dose sparing, PTV dose escalation is considerably safer. Isocentric-4π is sufficient to achieve the

  14. Automated treatment planning for a dedicated multi-source intra-cranial radiosurgery treatment unit accounting for overlapping structures and dose homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Ghobadi, Kimia; Ghaffari, Hamid R. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Aleman, Dionne M. [Department of Mechanical and Industrial Engineering, University of Toronto, Ontario M5S 3G8 (Canada); Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario M5T 3M6 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Ontario M5T 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Ontario M5S 3E2 (Canada); Department of Medical Biophysics, University of Toronto, Ontario M5G 2M9 (Canada); Institute of Biomaterial and Biomedical Engineering, University of Toronto, Ontario M5S 2J7 (Canada); Techna Institute, University Health Network, Ontario M5G 1P5 (Canada); Ontario Cancer Institute, Ontario M5G 0A3 (Canada); Ruschin, Mark [Department of Medical Physics, Odette Cancer Centre, Toronto, Ontario M4N 3M5 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2 (Canada)

    2013-09-15

    Purpose: The purpose of this work is to advance the two-step approach for Gamma Knife{sup ®} Perfexion™ (PFX) optimization to account for dose homogeneity and overlap between the planning target volume (PTV) and organs-at-risk (OARs).Methods: In the first step, a geometry-based algorithm is used to quickly select isocentre locations while explicitly accounting for PTV-OARs overlaps. In this approach, the PTV is divided into subvolumes based on the PTV-OARs overlaps and the distance of voxels to the overlaps. Only a few isocentres are selected in the overlap volume, and a higher number of isocentres are carefully selected among voxels that are immediately close to the overlap volume. In the second step, a convex optimization is solved to find the optimal combination of collimator sizes and their radiation duration for each isocentre location.Results: This two-step approach is tested on seven clinical cases (comprising 11 targets) for which the authors assess coverage, OARs dose, and homogeneity index and relate these parameters to the overlap fraction for each case. In terms of coverage, the mean V{sub 99} for the gross target volume (GTV) was 99.8% while the V{sub 95} for the PTV averaged at 94.6%, thus satisfying the clinical objectives of 99% for GTV and 95% for PTV, respectively. The mean relative dose to the brainstem was 87.7% of the prescription dose (with maximum 108%), while on average, 11.3% of the PTV overlapped with the brainstem. The mean beam-on time per fraction per dose was 8.6 min with calibration dose rate of 3.5 Gy/min, and the computational time averaged at 205 min. Compared with previous work involving single-fraction radiosurgery, the resulting plans were more homogeneous with average homogeneity index of 1.18 compared to 1.47.Conclusions: PFX treatment plans with homogeneous dose distribution can be achieved by inverse planning using geometric isocentre selection and mathematical modeling and optimization techniques. The quality of the

  15. Robust frameless stereotactic localization in extra-cranial radiotherapy

    International Nuclear Information System (INIS)

    Riboldi, Marco; Baroni, Guido; Spadea, Maria Francesca; Bassanini, Fabio; Tagaste, Barbara; Garibaldi, Cristina; Orecchia, Roberto; Pedotti, Antonio

    2006-01-01

    In the field of extra-cranial radiotherapy, several inaccuracies can make the application of frameless stereotactic localization techniques error-prone. When optical tracking systems based on surface fiducials are used, inter- and intra-fractional uncertainties in marker three-dimensional (3D) detection may lead to inexact tumor position estimation, resulting in erroneous patient setup. This is due to the fact that external fiducials misdetection results in deformation effects that are poorly handled in a rigid-body approach. In this work, the performance of two frameless stereotactic localization algorithms for 3D tumor position reconstruction in extra-cranial radiotherapy has been specifically tested. Two strategies, unweighted versus weighted, for stereotactic tumor localization were examined by exploiting data coming from 46 patients treated for extra-cranial lesions. Measured isocenter displacements and rotations were combined to define isocentric procedures, featuring 6 degrees of freedom, for correcting patient alignment (isocentric positioning correction). The sensitivity of the algorithms to uncertainties in the 3D localization of fiducials was investigated by means of 184 numerical simulations. The performance of the implemented isocentric positioning correction was compared to conventional point-based registration. The isocentric positioning correction algorithm was tested on a clinical dataset of inter-fractional and intra-fractional setup errors, which was collected by means of an optical tracker on the same group of patients. The weighted strategy exhibited a lower sensitivity to fiducial localization errors in simulated misalignments than those of the unweighted strategy. Isocenter 3D displacements provided by the weighted strategy were consistently smaller than those featured by the unweighted strategy. The peak decrease in median and quartile values of isocenter 3D displacements were 1.4 and 2.7 mm, respectively. Concerning clinical data, the

  16. Practical performance for CT simulator set up and commissioning for 3d radiotherapy

    International Nuclear Information System (INIS)

    Wang, Y.; Rinks, A.; Zealey, W.

    2004-01-01

    Full text: We present a summary of the protocol used to commission two GE LightSpeed and One Siemens CT-Sim for 3D radiotherapy in early 2004. The protocol defined was based on AAPM TG-66 and ACPSEM 1997 position paper. Scanning Med-TEC Iso-align Laser Alignment Device for three-D isocentre alignment 1. Couch Movement Accuracy for both manual and scanning movement checked before isocentre alignment, as the reference distance is required for the external isocentre setup. 2. Gantry scan rotation circle vertical and tilted angle alignment checked by overlaying the vertical and horizontal image coordinate lines using the aligned ball-bearings in the phantom to determine the gantry cross plane image vertical accuracy and tilt angle accuracy. 3. Zero scan position determined by scanning the horizontally set Med-Align phantom, and adjusting the phantom position forward and backward to match the image scanning centre. 4. Internal lasers position determined by the position of aligned Med-Align phantom after the scanning centre determined. 5. Couch top to Gantry Perpendicular checked by matching the couch axis in the longitudinal and lateral direction to the position of the laser lines determined according to the CT scanning orientation. 6. Couch Central Axis aligned to ensure the couch travels though the internal isocentre for the full range of longitudinal of movement. 7. External isocentre and laser focus can be determined by moving the couch back a set distance (50cm or 60cm normally) from the internal isocentre. Planning image transfer and DRR image alignment 1. Scanning Centre indicated on the planning image depends on the functionality of the planning system. Some planning systems load the image with the scanning centre at zero position, others load up the image with the absolute distance. 2. Zero Slice position aligned to the centre of the phantom using the external laser. 3. Orientation and Distance were checked by scanning the Iso-align in both vertical and

  17. Hippocampal-Sparing Whole-Brain Radiotherapy: A 'How-To' Technique Using Helical Tomotherapy and Linear Accelerator-Based Intensity-Modulated Radiotherapy

    International Nuclear Information System (INIS)

    Gondi, Vinai; Tolakanahalli, Ranjini; Mehta, Minesh P.; Tewatia, Dinesh; Rowley, Howard; Kuo, John S.; Khuntia, Deepak; Tome, Wolfgang A.

    2010-01-01

    Purpose: Sparing the hippocampus during cranial irradiation poses important technical challenges with respect to contouring and treatment planning. Herein we report our preliminary experience with whole-brain radiotherapy using hippocampal sparing for patients with brain metastases. Methods and Materials: Five anonymous patients previously treated with whole-brain radiotherapy with hippocampal sparing were reviewed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5-mm volumetric expansion around the hippocampus. Helical tomotherapy and linear accelerator (LINAC)-based intensity-modulated radiotherapy (IMRT) treatment plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the hippocampal avoidance volume was 3.3 cm 3 , occupying 2.1% of the whole-brain planned target volume. Helical tomotherapy spared the hippocampus, with a median dose of 5.5 Gy and maximum dose of 12.8 Gy. LINAC-based IMRT spared the hippocampus, with a median dose of 7.8 Gy and maximum dose of 15.3 Gy. On a per-fraction basis, mean dose to the hippocampus (normalized to 2-Gy fractions) was reduced by 87% to 0.49 Gy 2 using helical tomotherapy and by 81% to 0.73 Gy 2 using LINAC-based IMRT. Target coverage and homogeneity was acceptable with both IMRT modalities, with differences largely attributed to more rapid dose fall-off with helical tomotherapy. Conclusion: Modern IMRT techniques allow for sparing of the hippocampus with acceptable target coverage and homogeneity. Based on compelling preclinical evidence, a Phase II cooperative group trial has been developed to test the postulated neurocognitive benefit.

  18. 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.

  19. 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.

  20. Results of a Conservative Dose Plan Linear Accelerator-Based Stereotactic Radiosurgery for Pediatric Intracranial Arteriovenous Malformations.

    Science.gov (United States)

    Rajshekhar, Vedantam; Moorthy, Ranjith K; Jeyaseelan, Visalakshi; John, Subhashini; Rangad, Faith; Viswanathan, P N; Ravindran, Paul; Singh, Rabiraja

    2016-11-01

    To evaluate the obliteration rate and clinical outcome following linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) for intracranial arteriovenous malformation (AVM) in pediatric patients (age ≤18 years). Factors associated with the obliteration rate and neurologic complications were studied retrospectively in pediatric patients who underwent LINAC-based SRS for AVM between June 1995 and May 2014. The study cohort comprised 36 males and 33 females, with a median age at the time of SRS of 14 years (range, 7-18 years). The mean AVM volume was 8.5 ± 8.7 cc (range, 0.6-41.8 cc). The median marginal dose of radiation delivered was 15 Gy (range, 9-20 Gy). Magnetic resonance imaging (MRI) demonstrated complete obliteration of the AVM in 44 of the 69 patients (63.8%), at a mean follow up of 27.5 months (range, 12-90 months). On subgroup analysis, 41 of the 53 AVMs of ≤14 cc in volume (77.3%) were obliterated. AVMs with a modified AVM radiosurgery score <1 had significantly shorter obliteration times from the time of SRS (P = .006). On multivariate analysis, the mean marginal dose of radiation delivered to the AVM was the sole significant predictor of obliteration (odds ratio, 1.6; 95% confidence interval, 1 to 2.4). A modest median marginal dose of 15 Gy (16 Gy in the obliterated AVM group vs. 12 Gy in the nonobliterated group) resulted in an obliteration rate of 66.7% after LINAC-based SRS for intracranial AVM, with low rate. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Evaluation of permanent I-125 prostate implants using radiographs and MRI

    International Nuclear Information System (INIS)

    Moerland, M.A.; Beersma, R.; Bhagwandien, R.; Wijrdeman, H.K.; Battermann, J.J.

    1995-01-01

    Introduction: Localized prostatic cancer is managed by radical prostatectomy, external beam irradiation or a permanent implant with I-125 seeds. Permanent implants are indicated for small tumours (T1-T2) with a well to moderate histological differentiation. The technique used is a transrectal ultrasound guided transperineal implantation technique, which aims for a seed and dose distribution such that the initial doserate line of 7.8 cGy/h encompasses the prostate resulting in an accumulated dose of 160 Gy. Up till now the seed and dose distribution is evaluated from isocentric radiographs, which do not show the relation with the prostate. Objectives: The aim of this study is the development of a technique to reconstruct and evaluate the seed and dose distribution within the prostate. Methods: Twenty patients underwent radiography on the simulator and scanning on a whole body NMR system within 3 days after implantation of the I-125 seeds. Isocentric radiographs were used for reconstruction of the seed distribution, after which registration with the MR images provided the seed positions in relation to the prostate. Volume dose histograms were used to evaluate the implants. Results: The I-125 seeds and the prostate anatomy were well depicted on T1-weighted spin echo images with minimal read out gradient strength. To date, ten implants were evaluated. According to our method, the prostate volumes receiving the prescribed dose of 160 Gy ranged from 30 to 70% of the total prostate volumes. Conclusion: The combination of isocentric radiographs and MRI enables reconstruction of the seed and dose distribution in relation to the prostate and the computation of dose volume histograms, which may be of value in the evaluation of implant quality

  2. Photon and electron collimator effects on electron output and abutting segments in energy modulated electron therapy

    International Nuclear Information System (INIS)

    Olofsson, Lennart; Karlsson, Magnus G.; Karlsson, Mikael

    2005-01-01

    In energy modulated electron therapy a large fraction of the segments will be arranged as abutting segments where inhomogeneities in segment matching regions must be kept as small as possible. Furthermore, the output variation between different segments should be minimized and must in all cases be well predicted. For electron therapy with add-on collimators, both the electron MLC (eMLC) and the photon MLC (xMLC) contribute to these effects when an xMLC tracking technique is utilized to reduce the x-ray induced leakage. Two add-on electron collimator geometries have been analyzed using Monte Carlo simulations: One isocentric eMLC geometry with an isocentric clearance of 35 cm and air or helium in the treatment head, and one conventional proximity geometry with a clearance of 5 cm and air in the treatment head. The electron fluence output for 22.5 MeV electrons is not significantly affected by the xMLC if the shielding margins are larger than 2-3 cm. For small field sizes and 9.6 MeV electrons, the isocentric design with helium in the treatment head or shielding margins larger than 3 cm is needed to avoid a reduced electron output. Dose inhomogeneity in the matching region of electron segments is, in general, small when collimator positions are adjusted to account for divergence in the field. The effect of xMLC tracking on the electron output can be made negligible while still obtaining a substantially reduced x-ray leakage contribution. Collimator scattering effects do not interfere significantly when abutting beam techniques are properly applied

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

    International Nuclear Information System (INIS)

    Siemann, R.H.

    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

  4. The 4th Generation Light Source at Jefferson Lab

    International Nuclear Information System (INIS)

    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 Shinn; Christopher Tennant; Richard Walker; Shukui Zhang; Gwyn Williams

    2007-01-01

    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

  5. Stereotactic radiosurgery: incision less surgery

    International Nuclear Information System (INIS)

    Alvarez, Victor M.; Palma, Raul B.

    1997-01-01

    Stereotactic Radiosurgery (SRS) involves the application of focused high dose, high energy radiation to precisely (stereotactically) localized targets in the head without opening the skull for the purpose of destroying pathologic tissues like tumors, and also for producing discrete lesions for the relief of certain functional disorders. This procedure was pioneered by Lars Leksel in the 1950s and has progressively been refined with the development of more powerful computer technology and more precise and safer radiation delivery systems. The used of the Linear Accelerator (LINAC)- based radiosurgery system would be the most cost-effective and appropriate system for this treatment

  6. Failure mode and effects analysis and fault tree analysis of surface image guided cranial radiosurgery.

    Science.gov (United States)

    Manger, Ryan P; Paxton, Adam B; Pawlicki, Todd; Kim, Gwe-Ya

    2015-05-01

    Surface image guided, Linac-based radiosurgery (SIG-RS) is a modern approach for delivering radiosurgery that utilizes optical stereoscopic imaging to monitor the surface of the patient during treatment in lieu of using a head frame for patient immobilization. Considering the novelty of the SIG-RS approach and the severity of errors associated with delivery of large doses per fraction, a risk assessment should be conducted to identify potential hazards, determine their causes, and formulate mitigation strategies. The purpose of this work is to investigate SIG-RS using the combined application of failure modes and effects analysis (FMEA) and fault tree analysis (FTA), report on the effort required to complete the analysis, and evaluate the use of FTA in conjunction with FMEA. A multidisciplinary team was assembled to conduct the FMEA on the SIG-RS process. A process map detailing the steps of the SIG-RS was created to guide the FMEA. Failure modes were determined for each step in the SIG-RS process, and risk priority numbers (RPNs) were estimated for each failure mode to facilitate risk stratification. The failure modes were ranked by RPN, and FTA was used to determine the root factors contributing to the riskiest failure modes. Using the FTA, mitigation strategies were formulated to address the root factors and reduce the risk of the process. The RPNs were re-estimated based on the mitigation strategies to determine the margin of risk reduction. The FMEA and FTAs for the top two failure modes required an effort of 36 person-hours (30 person-hours for the FMEA and 6 person-hours for two FTAs). The SIG-RS process consisted of 13 major subprocesses and 91 steps, which amounted to 167 failure modes. Of the 91 steps, 16 were directly related to surface imaging. Twenty-five failure modes resulted in a RPN of 100 or greater. Only one of these top 25 failure modes was specific to surface imaging. The riskiest surface imaging failure mode had an overall RPN-rank of eighth

  7. 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.

  8. 6 MeV RF Linac for cargo scanning and industrial radiography

    International Nuclear Information System (INIS)

    2017-01-01

    RF Linac-based X-ray sources are very widely used for cargo-scanning and industrial X-ray radiography applications. A 6 MeV on-axis coupled-cavity S-band RF linac has been designed, developed and tested successfully at Electron Beam Centre, Navi Mumbai. This facility falls under the purview of BARC Safety Council, which has conducted safety reviews and awarded regulatory clearances for the operation of the linac system. This paper outlines the salient features of the 6 MeV linac, its safety aspects and test results. A brief history of regulatory aspects is also presented

  9. Large aperture contact ionized Cs+1 ion source for an induction linac

    International Nuclear Information System (INIS)

    Abbott, S.; Chupp, W.; Faltens, A.; Herrmannsfeldt, W.; Hoyer, E.; Keefe, D.; Kim, C.H.; Rosenblum, S.; Shiloh, J.

    1979-03-01

    A 500 KeV one-ampere Cs +1 ion beam has been generated by contact ionization with a 30 cm dia. iridium hot plate. Reproducibility of space charge limited ion current wave forms at repetition rates up to 1 Hz has been verified. The beam is characterized to be very bright and suitable as an ion source for the induction linac based heavy ion fusion scheme. The hot anode plate was found to be reliable and self-cleaning during the operation

  10. 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.

  11. Beam energy variability and other system considerations for a deuteron linac materials research neutron source

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1989-01-01

    There are many overall system aspects and tradeoffs that must be considered in the design of a deuteron linac based neutron source for materials research, in order to obtain a facility with the best possible response to the user's needs, efficient and reliable operation and maintenance, at the optimum construction and operating cost. These considerations should be included in the facility design from the earliest conceptual stages, and rechecked at each stage to insure consistency and balance. Some of system requirements, particularly that of beam energy variability and its implications, are outlined in this talk. (author)

  12. 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

  13. HIBALL-II - an improved conceptual heavy ion beam driven fusion reactor study

    International Nuclear Information System (INIS)

    Badger, B.; Corradini, M.; El-Guebaly, L.; Engelstad, R.; Henderson, D.; Klein, A.; Kulcinski, G.; Larsen, E.; Lovell, E.; Moses, G.; Peterson, R.; Pong, L.; Sawan, M.; Sviatoslavsky, I.; Symon, K.; Vogelsang, W.; White, A.; Wittenberg, L.; Beckert, K.; Bock, R.; Boehne, D.; Hofmann, I.; Keller, R.; Mueller, R.; Bozsik, I.; Jahnke, A.; Brezina, J.; Nestle, H.; Wendel, W.; Wollnik, H.; Lessmann, E.; Froehlich, R.; Goel, B.; Hoebel, W.; Kessler, G.; Moellendorff, U. von; Moritz, N.; Plute, K.; Schretzmann, K.; Sze, D.

    1985-07-01

    An improved design of the HIBALL inertial-confinement fusion power station is presented. The new RF-linac based heavy ion driver has improved concepts for beam stacking, bunching and final focusing. The new target design takes into account radiation transport effects in a coarse approximation. The system of four reactors with a net total output of 3.8 GW electric is essentially the same as described earlier, however, progress in the analysis has enhanced its credibility and self-consistency. Considerations of environmental and safety aspects and cost estimates are given. (orig.) [de

  14. Pilot material handling system for radiation processing of agricultural and medical products

    International Nuclear Information System (INIS)

    Sandha, R.S.; Nageswar Rao, J; Dwivedi, Jishnu; Petwal, V.C.; Soni, H.C.

    2005-01-01

    A 10 MeV, 10 kW electron LINAC based radiation processing facility is being constructed at Centre for Advanced Technology, Indore for radiation processing of various food products like potatoes, onion, spices, home pack items and medical sterilization. A pilot material handling system has been designed, manufactured, and installed at CAT to verify process parameters viz. conveying speed, dose uniformity, and to study the effect of packing shape and size for radiation processing of different product. This paper describes various features of pilot material handling system. (author)

  15. Independent collimators are sufficient to conform and combine adjacent fields?; Os colimadores independentes sao suficientes para conformar e combinar campos adjacentes?

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Neto, Enock de A. [Hospital Sirio Libanes, Sao Paulo, SP (Brazil). Sociedade Beneficente de Senhoras. Servico de Radioterapia; Santos Neto, Geraldo [Grupo COI, Rio de Janeiro, RJ (Brazil). Servico de Radioterapia; Sant' Anna, Marcelo C., E-mail: enock92@gmail.com [RADCLIN Centro de Oncologia, Volta Redonda, RJ (Brazil). Servico de Radioterapia

    2014-12-15

    Consider a radiotherapy treatment in which the tumor is located in the region of head and neck. In general, isocentric technique combined with three tangents half-beam fields are used. How these fields must be collimated? We show that the combination of independent collimators and multi-leaf results in a uniform dose in the region which these fields touch each other. Moreover, we recommend a setup that minimizes the heterogeneity for LINAC's that doesn't possess a multi-leaf collimator. (author)

  16. Possibility of construction in Bulgaria of a fast neutron therapy center on the base of the U-250 isochronous cyclotron

    International Nuclear Information System (INIS)

    Angelov, V.A.; Enchevich, I.B.

    1985-01-01

    Development of oncological disease treatment by fast neutrons in the world practice is reviewed. Main radiobiological results, which point to peculiarities of neutron therapy in comparison with standard X-ray therapy are considered. Main requirements for devices to be met, used in fast neutron therapy, are enumerated. On the basis of it, the possibility of construction in Bulgaria a fast neutron therapy center using the U-250 multipurpose cyclotron has been made. The conclusion is made that the main parameters of a proton beam in combination with an isocentrical head as a fast neutron source will create the conditions for realization of high-efficiency neutron therapy

  17. Three-dimensional irradiation planning of laryngeal and hypopharyngeal cancers based on phantom examinations Pt. 1

    International Nuclear Information System (INIS)

    Esik, Olga; Schlegel, Wolfgang; Doll, Josef; Nemeth, Gyoergy; Lorenz, W.J.

    1989-01-01

    Three-dimensional dose distributions were computed for the photon radiotherapy of laryngeal and hypopharyngeal cancers using a pair of opposing lateral beams in fixed positions. Treatment plans obtained under various irradiation conditions ( 60 Co gamma unit, photon beams from a 8 MeV and a 15 MeV linear accelerator) are analyzed and compared. The 8 MeV and 15 MeV plans are somewhat superior to the cobalt ones in all cases. Simulations show that extreme care is needed in positioning the isocentre: an accuracy of ±3 mm is required in the median sagittal plane. (author) 21 refs.; 11 figs

  18. Evaluation of the uncertainties in the TLD radiosurgery postal dose system

    International Nuclear Information System (INIS)

    Campos, Luciana Tourinho; Leite, Sandro Passos; Almeida, Carlos Eduardo Veloso de; Magalhães, Luís Alexandre Gonçalves

    2017-01-01

    Radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. The Radiological Science Laboratory (LCR/UERJ) operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy and the dosimetric conditions of the TPS. The programme works in such a way those TLDs are sent to the centre where they are to be irradiated to a certain dose. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data. (author)

  19. Special set-up and treatment techniques for the radiotherapy of pediatric malignancies

    International Nuclear Information System (INIS)

    Martinez, A.; Donaldson, S.S.; Bagshaw, M.A.

    1977-01-01

    The prevention of serious and long term complications of treatment have become as important a consideration in the therapy of children with malignant disease as the goal of tumor control. This balance requires meticulous treatment planning and attention to the treatment preparation and immobilization techniques when radiotherapy is administered to children. Accurate localization of tumor volume and daily reproducibility is essential for delivering precise irradiation. Four special set-up and treatment techniques which have a specific usefulness in radiotherapy for pediatric malignancies are defined and illustrated with the aid of clinical cases. They include the three point set-up, the split beam technique, the isocentric technique, and the strinking field technique

  20. Evaluation of the uncertainties in the TLD radiosurgery postal dose system

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Luciana Tourinho; Leite, Sandro Passos; Almeida, Carlos Eduardo Veloso de; Magalhães, Luís Alexandre Gonçalves, E-mail: tc_luciana@yahoo.com.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. The Radiological Science Laboratory (LCR/UERJ) operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy and the dosimetric conditions of the TPS. The programme works in such a way those TLDs are sent to the centre where they are to be irradiated to a certain dose. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data. (author)

  1. Installation and testing of a hospital-based cyclotron for radiation therapy and isotope production

    International Nuclear Information System (INIS)

    Almond, P.R.; Marbach, J.R.; Otte, V.A.

    1983-01-01

    A hospital based cyclotron is under installation at The University of Texas M.D. Anderson Hospital in Houston. This machine will be used for the production of radioactive isotopes and for the generation of neutrons for the radiotherapy treatment of cancer. It is a Cyclotron Corporation CP-42 negative proton accelerator. For neutron production the protons are transported through an isocentrically mounted beam transport system that can be rotated around the patient. The shielding requirements of this facility will be described as will the initial measurements on the characteristics of the neutron beam

  2. Superconductivity in Medicine

    Science.gov (United States)

    Alonso, Jose R.; Antaya, Timothy A.

    2012-01-01

    Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

  3. R&D Studies of the ATLAS LAr Calorimeter Readout Electronics for super-LHC

    CERN Document Server

    Chen, H

    2009-01-01

    The ATLAS Liquid Argon (LAr) calorimeters are high precision, high sensitivity and high granularity detectors designed to provide precision measurements of electrons, photons, jets and missing transverse energy. 180,000 signals are digitized and processed real-time on detector, to provide energy and time deposited in each detector element at every occurrence of the L1-trigger. A luminosity upgrade (x10) of the LHC will occur around 2016. The current readout electronics will have to be upgraded to sustain the higher radiation levels. A completely innovative readout scheme is being developed. The frontend readout will send out data continuously at each bunch crossing through highspeed radiation resistant optical links. The data (100Gbps each board) will be processed real-time with the possibility of implementing trigger algorithms for clusters and electron/photon identification at a much higher granularity than what currently implemented. We present here an overview of the R&D activities and architectural s...

  4. Photoelectric effect in the relativistic domain revealed by the time-reversed process for highly charged uranium ions

    International Nuclear Information System (INIS)

    Stoehlker, T.; Mokler, P.H.; Kozhuharov, C.; Warczak, A.

    1996-10-01

    The photoelectric effect in the near relativistic energy regime of 80 to 350 keV is studied by the time-reversed process in ion-atom collisions, i.e. by the radiative capture of a quasi-free target electron. We review shell and subshell differential photon-angular distribution studies of radiative capture into highly-charged uranium ions. The experimental data are compared with exact relativistic calculations and give detailed insight into both the atomic structure of high-Z few-electron ions and into the fundamental electron-photon interaction process involved. In particular it is shown that the angular-differential measurements provide a unique method to study the magnetic interaction in relativistic electron-photon encoun- (orig.)

  5. Electroluminescence Caused by the Transport of Interacting Electrons through Parallel Quantum Dots in a Photon Cavity

    Science.gov (United States)

    Gudmundsson, Vidar; Abdulla, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

    2018-02-01

    We show that a Rabi-splitting of the states of strongly interacting electrons in parallel quantum dots embedded in a short quantum wire placed in a photon cavity can be produced by either the para- or the dia-magnetic electron-photon interactions when the geometry of the system is properly accounted for and the photon field is tuned close to a resonance with the electron system. We use these two resonances to explore the electroluminescence caused by the transport of electrons through the one- and two-electron ground states of the system and their corresponding conventional and vacuum electroluminescense as the central system is opened up by coupling it to external leads acting as electron reservoirs. Our analysis indicates that high-order electron-photon processes are necessary to adequately construct the cavity-photon dressed electron states needed to describe both types of electroluminescence.

  6. Monte Carlo simulation of gas Cerenkov detectors

    International Nuclear Information System (INIS)

    Mack, J.M.; Jain, M.; Jordan, T.M.

    1984-01-01

    Theoretical study of selected gamma-ray and electron diagnostic necessitates coupling Cerenkov radiation to electron/photon cascades. A Cerenkov production model and its incorporation into a general geometry Monte Carlo coupled electron/photon transport code is discussed. A special optical photon ray-trace is implemented using bulk optical properties assigned to each Monte Carlo zone. Good agreement exists between experimental and calculated Cerenkov data in the case of a carbon-dioxide gas Cerenkov detector experiment. Cerenkov production and threshold data are presented for a typical carbon-dioxide gas detector that converts a 16.7 MeV photon source to Cerenkov light, which is collected by optics and detected by a photomultiplier

  7. Neutral Pion Rejection at L2 using the CMS Endcap Preshower

    CERN Document Server

    Kyriakis, Aristotelis; Loukas, Demetrios; Mousa, Jehad; Seez, Christopher

    1999-01-01

    Applying a general Artificial Neural Network approach, we have examined the possibility of neutral pion rejection at the Level 2 Trigger stage ( L2) principally using information from the CMS Endcap Preshower. We have studied both pion/photon and pion/electron discrimination. For L2 the hope was to achieve some useful pion/electron discrimination for a high electron efficiency. For a single electron/photon efficiency of 95% the results show that no useful rejection of neutral pions against electrons/photons can be obtained using this algorithm alone, due to the presence of tracker material. If the efficiency is lowered or information from the tracker is available, the rejection can increase dramatically. This will be the case for off-line analyses.

  8. A Halo Event observed by the Hybrid Experiment at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    Aoki, H.; Hashimoto, K.; Honda, K.; Inoue, N.; Kawasumi, N.; Martinic, N.; Navia O, C.; Ochi, N.; Ohmori, N.; Ohsawa, A.; Oliveira, C.; Shinozaki, K.; Tamada, M.; Ticona, R.; Tsushima, I.

    2006-01-01

    An experiment using an air shower array, a hadron calorimeter and an emulsion chamber is under way at Mt. Chacaltaya (5200 m, Bolivia). One of the highest energy events, having a halo (∼ 1 cm) in the centre of the family together with many γ-ray and hadron showers, is analyzed in detail. Available data for the event are on the halo (E halo =750 TeV) and on the high energy particles of electron/photon components by the emulsion chamber, and on the characteristics of the accompanied air shower (Ne=7.0x10 7 , s=0.59) by the air shower array. The diagram of the air shower size and the total energy of electron/photon components in the family, which shows discrepancy between the experimental data and simulated events (QGSJET code for nuclear collisions) in our previous reports, is discussed including the present event

  9. Electro-magnetic cascade calculation using EGS4 code

    International Nuclear Information System (INIS)

    Namito, Yoshihito; Hirayama, Hideo

    2001-01-01

    The outline of the general-purpose electron-photon transport code EGS4 (Electron-Gamma-Shower Version 4) is described. In section 1, the history of the electron photon Monte Carlo transport code toward EGS4 is described. In section 2, the features of the EGS4 and the physical processes treated, cross section preparation and language is explained. The upper energy limit of EGS4 is a few thousand GeV. The lower energy limit of EGS4 is 1 keV and 10 keV for photon and electron, respectively. In section 3, particle transport method in EGS4 code is discussed. The points are; condensed history method, continuous slowing down approximation and multiple scattering approximation. Order of the particle transport calculation is also mentioned. The switches to control scoring routine AUSGAB is listed. In section 4, the output from the code is described. In section 5, several benchmark calculations are described. (author)

  10. Relaxation of electron energy in the polar semiconductor double quantum dots

    Czech Academy of Sciences Publication Activity Database

    Král, Karel; Khás, Zdeněk; Zdeněk, Petr; Čerňanský, Marian; Lin, C. Y.

    2002-01-01

    Roč. 314, - (2002), s. 490-493 ISSN 0921-4526 R&D Projects: GA AV ČR IAA1010113; GA MŠk OC P5.20 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum dots * relaxation * double quantum dots * electron-photon interaction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.609, year: 2002

  11. Automated Monte Carlo biasing for photon-generated electrons near surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Brian Claude; Crawford, Martin James; Kensek, Ronald Patrick

    2009-09-01

    This report describes efforts to automate the biasing of coupled electron-photon Monte Carlo particle transport calculations. The approach was based on weight-windows biasing. Weight-window settings were determined using adjoint-flux Monte Carlo calculations. A variety of algorithms were investigated for adaptivity of the Monte Carlo tallies. Tree data structures were used to investigate spatial partitioning. Functional-expansion tallies were used to investigate higher-order spatial representations.

  12. Noncommutative QED and anomalous dipole moments

    International Nuclear Information System (INIS)

    Riad, I.F.; Sheikh-Jabbari, M.M.

    2000-09-01

    We study QED on noncommutative spaces, NCQED. In particular we present the detailed calculation for the noncommutative electron-photon vertex and show that the Ward identity is satisfied. We discuss that in the noncommutative case moving electron will show electric dipole effects. In addition, we work out the electric and magnetic dipole moments up to one loop level. For the magnetic moment we show that noncommutative electron has an intrinsic (spin independent) magnetic moment. (author)

  13. SASP - Symposium on atomic, cluster and surface physics `94

    Energy Technology Data Exchange (ETDEWEB)

    Maerk, T D; Schrittwieser, R; Smith, D

    1994-12-31

    This international symposium (Founding Chairman: W. Lindinger, Innsbruck) is one in a continuing biennial series of conferences which seeks to promote the growth of scientific knowledge and its effective exchange among scientists in the field of atomic, molecular, cluster and surface physics and related areas. The symposium deals in particular with interactions between ions, electrons, photons, atoms, molecules, and clusters and their interactions with surfaces. (author).

  14. MAESTRO: Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology

    Science.gov (United States)

    Barthe, Jean; Hugon, Régis; Nicolai, Jean Philippe

    2007-12-01

    The integrated project MAESTRO (Methods and Advanced Equipment for Simulation and Treatment in Radio-Oncology) under contract with the European Commission in life sciences FP6 (LSHC-CT-2004-503564), concerns innovative research to develop and validate in clinical conditions, advanced methods and equipment needed in cancer treatment for new modalities in high-conformal external radiotherapy using electrons, photons and protons beams of high energy.

  15. Status of PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Sempau, J. [Univ. Politecnica de Catalunya, Barcelona (Spain). Inst. de Tecniques Energetiques; Fernandez-Varea, J.M.; Salvat, F.; Benedito, E.; Dingfelder, M.; Oulad Ben Tahar, H. [Barcelona Univ. (ES). Societat Catalana de Fisica (IEC); Llovet, X. [Barcelona Univ. (Spain). Serveis Cientificotecnics; Acosta, E. [Univ. Nacional de Cordoba (Argentina). Facultad de Matematica, Astronomia y Fisica; Sanchez-Reyes, A.; Asenjo, J. [Hospital Clinic de Barcelona (Spain)

    2001-07-01

    PENELOPE is a general-purpose Monte Carlo code system for the simulation of coupled electron-photon transport in complex material structures. Its most characteristic feature is the systematic use of mixed simulation for electrons and positrons. This not only improves the accuracy of the simulation but also simplifies the structure and operation of the code. The reliability of the code has been tested by means of extensive comparisons with experimental data and with results from analog codes. (orig.)

  16. Confined exciton spectroscopy

    International Nuclear Information System (INIS)

    Torres, Clivia M.S.

    1998-01-01

    Full text: In this work, the exciton is considered as a sensor of the electronic and optical properties of materials such as semiconductors, which have size compared to the exciton De Broglie wavelength, approximately 20 nm, depending on the semiconductor. Examples of electron-phonon, electron-electron, photon-electron, exciton-polariton, phonon-plasmon, are presented, under different confinement conditions such as quantum wells, superlattices

  17. Optical properties and electron transport in low-dimensional nanostructures

    Czech Academy of Sciences Publication Activity Database

    Král, Karel; Menšík, Miroslav

    2011-01-01

    Roč. 54, 2-2 (2011), s. 4-13 ISSN 0021-3411 R&D Projects: GA MŠk(CZ) OC10007 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40500505 Keywords : quantum dots * electron -photon interaction * optical properties * electron relaxation * DNA molecule Subject RIV: BE - The oretical Physics http://elibrary.ru/contents.asp?issueid=1010336

  18. Topics in gauge theories and the unification of elementary particle interactions. Progress report, February 1, 1993--January 31, 1994

    International Nuclear Information System (INIS)

    Srivastava, Y.N.; Vaughn, M.T.

    1994-02-01

    We report on work done by the principal investigators (Y.N. Srivastava and M.T. Vaughn) and their collaborators on (1) Interference Between Past and Future Events in Neutral Kaon Decays in Φ → K bar K; (2) Single Top Production at LEP II and at Electron -- Photon Colliders; (3) Renormahzation Group Studies of Unified Gauge Theories; (4) Analysis of Classical Field Theories; and (5) Quantum Effects of Strong Classical Electromagnetic Fields

  19. The ATLAS Level-1 Calorimeter Trigger

    International Nuclear Information System (INIS)

    Achenbach, R; Andrei, V; Adragna, P; Apostologlou, P; Barnett, B M; Brawn, I P; Davis, A O; Edwards, J P; Asman, B; Bohm, C; Ay, C; Bauss, B; Bendel, M; Dahlhoff, A; Eckweiler, S; Booth, J R A; Thomas, P Bright; Charlton, D G; Collins, N J; Curtis, C J

    2008-01-01

    The ATLAS Level-1 Calorimeter Trigger uses reduced-granularity information from all the ATLAS calorimeters to search for high transverse-energy electrons, photons, τ leptons and jets, as well as high missing and total transverse energy. The calorimeter trigger electronics has a fixed latency of about 1 μs, using programmable custom-built digital electronics. This paper describes the Calorimeter Trigger hardware, as installed in the ATLAS electronics cavern

  20. The ATLAS Level-1 Calorimeter Trigger

    Energy Technology Data Exchange (ETDEWEB)

    Achenbach, R; Andrei, V [Kirchhoff-Institut fuer Physik, University of Heidelberg, D-69120 Heidelberg (Germany); Adragna, P [Physics Department, Queen Mary, University of London, London E1 4NS (United Kingdom); Apostologlou, P; Barnett, B M; Brawn, I P; Davis, A O; Edwards, J P [STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (United Kingdom); Asman, B; Bohm, C [Fysikum, Stockholm University, SE-106 91 Stockholm (Sweden); Ay, C; Bauss, B; Bendel, M; Dahlhoff, A; Eckweiler, S [Institut fuer Physik, University of Mainz, D-55099 Mainz (Germany); Booth, J R A; Thomas, P Bright; Charlton, D G; Collins, N J; Curtis, C J [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)], E-mail: e.eisenhandler@qmul.ac.uk (and others)

    2008-03-15

    The ATLAS Level-1 Calorimeter Trigger uses reduced-granularity information from all the ATLAS calorimeters to search for high transverse-energy electrons, photons, {tau} leptons and jets, as well as high missing and total transverse energy. The calorimeter trigger electronics has a fixed latency of about 1 {mu}s, using programmable custom-built digital electronics. This paper describes the Calorimeter Trigger hardware, as installed in the ATLAS electronics cavern.

  1. Structure and operation of the ITS code system

    International Nuclear Information System (INIS)

    Halbleib, J.

    1988-01-01

    The TIGER series of time-independent coupled electron-photon Monte Carlo transport codes is a group of multimaterial and multidimensional codes designed to provide a state-of-the-art description of the production and transport of the electron-photon cascade by combining microscopic photon transport with a macroscopic random walk for electron transport. Major contributors to its evolution are listed. The author and his associates are primarily code users rather than code developers, and have borrowed freely from existing work wherever possible. Nevertheless, their efforts have resulted in various software packages for describing the production and transport of the electron-photon cascade that they found sufficiently useful to warrant dissemination through the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory. The ITS system (Integrated TIGER Series) represents the organization and integration of this combined software, along with much additional capability from previously unreleased work, into a single convenient package of exceptional user friendliness and portability. Emphasis is on simplicity and flexibility of application without sacrificing the rigor or sophistication of the physical model

  2. Radiosurgery for cerebral arteriovenous malformation during pregnancy: A case report focusing on fetal exposure to radiation

    Science.gov (United States)

    Nagayama, Kazuki; Kurita, Hiroki; Tonari, Ayako; Takayama, Makoto; Shiokawa, Yoshiaki

    2010-01-01

    Introduction: We present the case of a pregnant woman who underwent linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) and we discuss the fetal exposure to radiation. Clinical Presentation: A 20-year-old woman at 18 weeks of gestation presented with right cerebral hemorrhage and underwent urgent evacuation of the hematoma. She recovered well after surgery, but cerebral angiography after the surgery revealed a small deeply seated arteriovenous malformation (AVM) in the right frontal lobe extending to the right basal ganglia. Methods and Results: We examined the diffuse AVM and treated it with LINAC-based SRS at 24 weeks of gestation. Before SRS, the fetus was exposed to a radiation dose of 8.26 mGy, which was estimated by conducting an experiment using an adult RANDO phantom, and a radiophotoluminescent (RPL) glass rod dosimeter (GRD) system. The patient underwent Caesarean delivery at 36 weeks of gestation and gave birth to a healthy baby. Conclusion: The exposure of fetus to radiation during SRS was exceedingly low. SRS can be used as an alternative treatment to microsurgery for resolving small deeply seated AVMs even in pregnant patients. PMID:22028762

  3. Effects of bone- and air-tissue inhomogeneities on the dose distributions of the Leksell Gamma Knife (registered) calculated with PENELOPE

    International Nuclear Information System (INIS)

    Al-Dweri, Feras M O; Rojas, E Leticia; Lallena, Antonio M

    2005-01-01

    Monte Carlo simulation with PENELOPE (version 2003) is applied to calculate Leksell Gamma Knife (registered) dose distributions for heterogeneous phantoms. The usual spherical water phantom is modified with a spherical bone shell simulating the skull and an air-filled cube simulating the frontal or maxillary sinuses. Different simulations of the 201 source configuration of the Gamma Knife have been carried out with a simplified model of the geometry of the source channel of the Gamma Knife recently tested for both single source and multisource configurations. The dose distributions determined for heterogeneous phantoms including the bone- and/or air-tissue interfaces show non-negligible differences with respect to those calculated for a homogeneous one, mainly when the Gamma Knife isocentre approaches the separation surfaces. Our findings confirm an important underdosage (∼10%) nearby the air-tissue interface, in accordance with previous results obtained with the PENELOPE code with a procedure different from ours. On the other hand, the presence of the spherical shell simulating the skull produces a few per cent underdosage at the isocentre wherever it is situated

  4. Beam testing of the lab model 2700 head magnet

    International Nuclear Information System (INIS)

    Hutcheon, R.M.; Gillies, B.A.

    1981-07-01

    A modern cancer therapy electron accelerator unit must satisfy many design constraints, one of which is the isocentric height above floor level. Usually 130 cm is considered the maximum height at which a nurse can work with a patient. The advent of higher energy machines has increasingly made this more difficult to achieve, as higher magnetic fields are required in the magnet that directs the beam onto the patient. A new 270 0 doubly achromatic magnet configuration has been developed which minimizes the isocentre height for a given maximum energy and maximum magnetic field. The system is an asymmetric two magnet configuration, with zero field index, equal fields and a bend of greater than 180 0 in the first magnet. It is compact, easy to manufacture and relatively insensitive to assembly tolerances. Energy defining slits are easily incorporated in the design and can readily be radiation shielded. Input and output beam matching and steering is easily accomplished with a compact input quadrupole doublet and small steering windings. The design and bench testing of such a head magnet for a 25 MeV electron accelerator is described in report AECL-7057. The present report details the testing of the magnet at both 10 and 21 MeV using the variable energy electron beam from the Therac 25 cancer therapy accelerator

  5. Quality assurance in fractionated stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Warrington, A.P.; Laing, R.W.; Brada, M.

    1994-01-01

    The recent development of fractionated stereotactic radiotherapy (SRT), which utilises the relocatable Gill-Thomas-Cosman frame (GTC 'repeat localiser'), requires comprehensive quality assurance (QA). This paper focuses on those QA procedures particularly relevant to fractionated SRT treatments, and which have been derived from the technique used at the Royal Marsden Hospital. They primarily relate to the following: (i) GTC frame fitting, initially in the mould room, and then at each imaging session and treatment fraction; (ii) checking of the linear accelerator beam geometry and alignment lasers; and (iii) setting up of the patient for each fraction of treatment. The precision of the fractionated technique therefore depends on monitoring the GTC frame relocation at each fitting, checking the accuracy of the radiation isocentre of the treatment unit, its coincidence with the patient alignment lasers and the adjustments required to set the patient up accurately. The results of our quality control checks show that setting up to a mean radiation isocentre using precisely set-up alignment lasers can be achievable to within 1 mm accuracy. When this is combined with a mean GTC frame relocatability of 1 mm on the patient, a 2-mm allowance between the prescribed isodose surface and the defined target volume is a realistic safety margin for this technique

  6. Quality assurance program for prototype stereotactic system developed for neptun 10 Pc linac

    International Nuclear Information System (INIS)

    Khoshbin Khoshnazar, A.R.; Bahreyni Toossi, M.T.; Hashemiyan, A.R.; Bahreyni Toossi, M.T.; Salek, R.

    2005-01-01

    A prototype stereotactic radiosurgery set was designed and constructed for a Neptun 10 Pc linac that is currently being used at Imam Reza hospital in Mashad. Materials and Methods: A complete quality assurance program was designed and performed for the constructed system including isocentric accuracy test, localization accuracy test, dose delivery accuracy test and leakage radiation test. Target simulator, control alignment device and plexiglass phantom which were parts of the developed hardware were used to fulfill quality assurance program. Results: The average isocentric shift resulted from the gantry rotation and couch turning were respectively obtained to be 1.4 and 2 mm. The average localization error in the three coordinates was found to be 2.2 mm. The total treatment uncertainty due to all of the probable errors in the system was equal to 4.32 mm. The dose delivery accuracy test was carried out, the result indicated a 3.7% difference between the given and measured dose. Conclusion: The quality assurance tests showed consistent performance of the constructed system within the accepted limits; however, some inconsistency might exist in certain cases. The safety of stereotactic radiosurgery system method is increased when the overall uncertainty is minimized nd the treatment of the lesions adjacent to critical organs is avoided

  7. Breast conserving surgery in locoregional treatment of breast carcinoma after Hodgkin lymphoma

    International Nuclear Information System (INIS)

    Haberer, S.; Le Scodan, R.; Kirova, Y.M.; Moisson, P.; Campana, F.; Fourquet, A.; Bollet, M.A.; Belin, L.; Savignoni, A.; Stevens, D.; Decaudin, D.; Pierga, J.Y.; Reyal, F.

    2012-01-01

    Purpose. - To report characteristics and outcome of breast cancer after irradiation for Hodgkin lymphoma with special focus on breast conservation surgery. Patients and methods. - Medical records of 72 women who developed either ductal carcinoma in situ or stage I-III invasive carcinoma of the breast after Hodgkin lymphoma between 1978 and 2009 were retrospectively reviewed. Results. - Median age at Hodgkin lymphoma diagnosis was 23 years old. Median total dose received by the mediastinum was 40 Gy, mostly by a mantle field technique. Breast cancer occurred after a median time interval of 21 years. Ductal invasive carcinoma and ductal carcinoma in situ represented respectively 71% and 19% of the cases. Locoregional treatment for breast cancer consisted of mastectomy with or without radiotherapy in 39 patients and of lumpectomy with or without adjuvant radiotherapy in 32 patients. The isocentric lateral decubitus radiation technique was used in 17 patients after breast conserving surgery (57%). With a median follow-up of 7 years, 5-year overall survival rate and locoregional control rate were respectively 74.5% and 82% for invasive carcinoma and 100% and 92% for in situ carcinoma. Thirteen patients died of progressive breast cancer and contralateral breast cancer was diagnosed in ten patients (14%). Conclusions. - Breast conserving treatment can be an option for breast cancers that occur after Hodgkin lymphoma despite prior thoracic irradiation. It should consist of lumpectomy and adjuvant breast radiotherapy with use of adequate techniques, such as the lateral decubitus isocentric position. (authors)

  8. Study of the IMRT interplay effect using a 4DCT Monte Carlo dose calculation.

    Science.gov (United States)

    Jensen, Michael D; Abdellatif, Ady; Chen, Jeff; Wong, Eugene

    2012-04-21

    Respiratory motion may lead to dose errors when treating thoracic and abdominal tumours with radiotherapy. The interplay between complex multileaf collimator patterns and patient respiratory motion could result in unintuitive dose changes. We have developed a treatment reconstruction simulation computer code that accounts for interplay effects by combining multileaf collimator controller log files, respiratory trace log files, 4DCT images and a Monte Carlo dose calculator. Two three-dimensional (3D) IMRT step-and-shoot plans, a concave target and integrated boost were delivered to a 1D rigid motion phantom. Three sets of experiments were performed with 100%, 50% and 25% duty cycle gating. The log files were collected, and five simulation types were performed on each data set: continuous isocentre shift, discrete isocentre shift, 4DCT, 4DCT delivery average and 4DCT plan average. Analysis was performed using 3D gamma analysis with passing criteria of 2%, 2 mm. The simulation framework was able to demonstrate that a single fraction of the integrated boost plan was more sensitive to interplay effects than the concave target. Gating was shown to reduce the interplay effects. We have developed a 4DCT Monte Carlo simulation method that accounts for IMRT interplay effects with respiratory motion by utilizing delivery log files.

  9. Design and construction of a novel compact doubly achromatic asymmetric 2700 magnet system for 25 MeV therapy electron accelerator

    International Nuclear Information System (INIS)

    Hutcheon, R.M.; Hodge, S.B.

    1980-09-01

    A modern cancer therapy electron accelerator unit must satisfy many design constraints, one of which is the isocentric height above floor level. Usually 130 cm is considered the maximum height at which a nurse can work with a patient. The advent of higher energy machines has increasingly made this more difficult to achieve, as higher magnetic fields are required in the magnet that directs the beam onto the patient. A new 270 degree doubly-achromatic magnet configuration has been developed which minimizes the isocentre height for a given maximum energy and maximum magnetic field. The system is an asymmetric two-magnet configuration, with zero field index, equal fields and a bend of greater than 180 degrees in the first magnet. It is compact, easy to manufacture and relatively insensitive to assembly tolerances. Energy defining slits are easily incorporated in the design and can readily be radiation shielded. Input and output beam matching and steering is easily accomplished with a compact input quadrupole doublet and small steering windings. This report details the design and bench testing of a head magnet for a 25 MeV electron accelerator with +- 10 percent energy acceptance. The output beam requirement is < 3 mm diameter with < +- 17 mrad angular divergence. (auth)

  10. Design principles and clinical possibilities with a new generation of radiation therapy equipment

    Energy Technology Data Exchange (ETDEWEB)

    Ruden, B P [Department of Hospital physics Karolinska institute, (Sudan)

    1997-12-31

    The main steps in the development of isocentric megavoltage external beam radiation therapy machines are briefly reviewed identifying three principal types or generations of equipment to date. The new fourth generation of equipment presented here is characterized by considerably increased flexibility in dose delivery through the use of scanned elementary electron and photon beams of very high quality. Furthermore, the wide energy range and the possibility of using high resolution multi leaf collimation with all beam modalities makes it possible to simplify irradiation techniques and increase the accuracy in dose delivery. The main design features are described including a dual magnet scanning system, a photon beam purging magnet, a helium atmosphere in the treatment head, a beam`s eye view video read-out system of the collimator setting and a radiotherapeutic computed tomography facility. Some of the clinical applications of this new type of radiation therapy machine are finally reviewed, such as the ease of performance, became flattening, beam filtering and compensation, and the simplification of many treatment techniques using the wide spectrum of high quality electron and photon beams. Finally, the interesting possibility of doing conformation and more general isocentric treatments with non-uniform beams using the multi leaf collimator and the scanning systems are demonstrated. 9 figs., 1 tab.

  11. An MCNP-based model for the evaluation of the photoneutron dose in high energy medical electron accelerators.

    Science.gov (United States)

    Carinou, Eleutheria; Stamatelatos, Ion Evangelos; Kamenopoulou, Vassiliki; Georgolopoulou, Paraskevi; Sandilos, Panayotis

    The development of a computational model for the treatment head of a medical electron accelerator (Elekta/Philips SL-18) by the Monte Carlo code mcnp-4C2 is discussed. The model includes the major components of the accelerator head and a pmma phantom representing the patient body. Calculations were performed for a 14 MeV electron beam impinging on the accelerator target and a 10 cmx10 cm beam area at the isocentre. The model was used in order to predict the neutron ambient dose equivalent at the isocentre level and moreover the neutron absorbed dose distribution within the phantom. Calculations were validated against experimental measurements performed by gold foil activation detectors. The results of this study indicated that the equivalent dose at tissues or organs adjacent to the treatment field due to photoneutrons could be up to 10% of the total peripheral dose, for the specific accelerator characteristics examined. Therefore, photoneutrons should be taken into account when accurate dose calculations are required to sensitive tissues that are adjacent to the therapeutic X-ray beam. The method described can be extended to other accelerators and collimation configurations as well, upon specification of treatment head component dimensions, composition and nominal accelerating potential.

  12. Effect of residual patient motion on dose distribution during image-guided robotic radiosurgery for skull tracking based on log file analysis

    International Nuclear Information System (INIS)

    Inoue, Mitsuhiro; Shiomi, Hiroya; Sato, Kengo

    2014-01-01

    The present study aimed to assess the effect of residual patient motion on dose distribution during intracranial image-guided robotic radiosurgery by analyzing the system log files. The dosimetric effect was analyzed according to the difference between the original and estimated dose distributions, including targeting error, caused by residual patient motion between two successive image acquisitions. One hundred twenty-eight treatments were analyzed. Forty-two patients were treated using the isocentric plan, and 86 patients were treated using the conformal (non-isocentric) plan. The median distance from the imaging center to the target was 55 mm, and the median interval between the acquisitions of sequential images was 79 s. The median translational residual patient motion was 0.1 mm for each axis, and the rotational residual patient motion was 0.1 deg for Δpitch and Δroll and 0.2 deg for Δyaw. The dose error for D 95 was within 1% in more than 95% of cases. The maximum dose error for D 10 to D 90 was within 2%. None of the studied parameters, including the interval between the acquisitions of sequential images, was significantly related to the dosimetric effect. The effect of residual patient motion on dose distribution was minimal. (author)

  13. Breast radiotherapy in the lateral decubitus position: A technique to prevent lung and heart irradiation

    International Nuclear Information System (INIS)

    Campana, Francois; Kirova, Youlia M.; Rosenwald, Jean-Claude; Dendale, Remi; Vilcoq, Jacques R.; Dreyfus, Helene; Fourquet, Alain

    2005-01-01

    Purpose: To present an original technique for breast radiotherapy, with the aim of limiting lung and heart irradiation, satisfying quality assurance criteria. Methods and Material: An original radiotherapy technique for breast irradiation has been developed at the Institute Curie in January 1996. It consists of isocentric breast irradiation in the lateral decubitus position (isocentric lateral decubitus [ILD]). This technique is indicated for voluminous or pendulous breasts needing breast irradiation only. Thin carbon fiber supports and special patient positioning devices have been developed especially for this technique. In vivo measurements were performed to check the dose distribution before the routine use of the technique. Results: ILD has been successfully implemented in routine practice, and 500 patients have been already treated. Breast radiotherapy is performed using a dose of 50 Gy at ICRU point in 25 fractions. ILD shows good homogeneity of the dose in breast treatment volume, treatment fields are perpendicular to the skin ensuring its protection, and extremely low dose is delivered to the underlying lung and heart. Conclusion: In cases of voluminous breasts or patients with a history of lung and heart disease, our technique provides several advantages over the conventional technique with opposing tangential fields. This technique improves the dose homogeneity according to the ICRU recommendations

  14. Resampling: An optimization method for inverse planning in robotic radiosurgery

    International Nuclear Information System (INIS)

    Schweikard, Achim; Schlaefer, Alexander; Adler, John R. Jr.

    2006-01-01

    By design, the range of beam directions in conventional radiosurgery are constrained to an isocentric array. However, the recent introduction of robotic radiosurgery dramatically increases the flexibility of targeting, and as a consequence, beams need be neither coplanar nor isocentric. Such a nonisocentric design permits a large number of distinct beam directions to be used in one single treatment. These major technical differences provide an opportunity to improve upon the well-established principles for treatment planning used with GammaKnife or LINAC radiosurgery. With this objective in mind, our group has developed over the past decade an inverse planning tool for robotic radiosurgery. This system first computes a set of beam directions, and then during an optimization step, weights each individual beam. Optimization begins with a feasibility query, the answer to which is derived through linear programming. This approach offers the advantage of completeness and avoids local optima. Final beam selection is based on heuristics. In this report we present and evaluate a new strategy for utilizing the advantages of linear programming to improve beam selection. Starting from an initial solution, a heuristically determined set of beams is added to the optimization problem, while beams with zero weight are removed. This process is repeated to sample a set of beams much larger compared with typical optimization. Experimental results indicate that the planning approach efficiently finds acceptable plans and that resampling can further improve its efficiency

  15. Ion-optical studies for a range adaptation method in ion beam therapy using a static wedge degrader combined with magnetic beam deflection

    International Nuclear Information System (INIS)

    Chaudhri, Naved; Saito, Nami; Bert, Christoph; Franczak, Bernhard; Steidl, Peter; Durante, Marco; Schardt, Dieter; Rietzel, Eike

    2010-01-01

    Fast radiological range adaptation of the ion beam is essential when target motion is mitigated by beam tracking using scanned ion beams for dose delivery. Electromagnetically controlled deflection of a well-focused ion beam on a small static wedge degrader positioned between two dipole magnets, inside the beam delivery system, has been considered as a fast range adaptation method. The principle of the range adaptation method was tested in experiments and Monte Carlo simulations for the therapy beam line at the GSI Helmholtz Centre for Heavy Ions Research. Based on the simulations, ion optical settings of beam deflection and realignment of the adapted beam were experimentally applied to the beam line, and additional tuning was manually performed. Different degrader shapes were employed for the energy adaptation. Measured and simulated beam profiles, i.e. lateral distribution and range in water at isocentre, were analysed and compared with the therapy beam values for beam scanning. Deflected beam positions of up to ±28 mm on degrader were performed which resulted in a range adaptation of up to ±15 mm water equivalence (WE). The maximum deviation between the measured adapted range from the nominal range adaptation was below 0.4 mm WE. In experiments, the width of the adapted beam at the isocentre was adjustable between 5 and 11 mm full width at half maximum. The results demonstrate the feasibility/proof of the proposed range adaptation method for beam tracking from the beam quality point of view.

  16. MO-G-201-04: Knowledge-Based Planning for Single-Isocenter Stereotactic Radiosurgery to Multiple Brain Metastases

    International Nuclear Information System (INIS)

    Ziemer, B; Shiraishi, S; Hattangadi-Gluth, J; Sanghvi, P; Moore, K

    2016-01-01

    Purpose: Single-isocenter, linac-based SRS for multiple brain metastases (multi-mets) can deliver highly conformal radiation doses and reduce overall patient treatment time compared to other therapy techniques. This study aims to quantify the dosimetric benefits of knowledge-based planning (KBP) for multi-met treatments. Methods: Using a previously-published KBP methodology (an artificial neural network (ANN) trained on single-target linac-based SRS plans), 3D dose distribution predictions for multi-met patients were obtained by treating each brain lesion as a solitary target and subsequently combining individual predictions into a single distribution using a dose-weighted geometric averaging to obtain the best results in the inter-target space. 17 previously-treated multi-met plans, with target numbers ranging from N=2–5, were used to validate the ANN predictions and subsequent KBP auto-planning routine. The fully-deliverable KBP plans were developed by converting dose distribution predictions into patient-specific optimization objectives while maintaining identical target normalizations (typically PTV V100%=D98%). Plan quality improvements were quantified by the difference between SRS quality metrics (QMs): δdQM=QM(clinical)-QM(KBP). QMs of interest were: gradient measure (GM), conformity index (CI), brain V10 and V5, brainstem D0.1cc and heterogeneity index (HI). Finally, overall plan quality was judged via blinded plan comparison by SRS-specializing physicians. Results: Two clinical plans were found to be significant outliers wherein plan quality was dramatically worse than KBP. Despite indicating KBP superiority, these were removed from the QM analysis to prevent skewing the results. In the remaining cases, clinical and KBP QMs were nearly identical with modest improvements in the KBP sample: δGM=0.12±0.56mm, δCI=−0.01±0.04, Brain δV10=0.8±2.6cc, brain δV5=6.3 ±10.7cc, brainstem δD0.1cc=0.06±1.19Gy and δHI= −0.04±0.05. Ultimately, 13/17 KBP

  17. 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

  18. MO-G-201-04: Knowledge-Based Planning for Single-Isocenter Stereotactic Radiosurgery to Multiple Brain Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, B [University of California, San Diego, La Jolla, CA (United States); Shiraishi, S [Mayo Clinic, Rochester, MN (United States); Hattangadi-Gluth, J; Sanghvi, P; Moore, K

    2016-06-15

    Purpose: Single-isocenter, linac-based SRS for multiple brain metastases (multi-mets) can deliver highly conformal radiation doses and reduce overall patient treatment time compared to other therapy techniques. This study aims to quantify the dosimetric benefits of knowledge-based planning (KBP) for multi-met treatments. Methods: Using a previously-published KBP methodology (an artificial neural network (ANN) trained on single-target linac-based SRS plans), 3D dose distribution predictions for multi-met patients were obtained by treating each brain lesion as a solitary target and subsequently combining individual predictions into a single distribution using a dose-weighted geometric averaging to obtain the best results in the inter-target space. 17 previously-treated multi-met plans, with target numbers ranging from N=2–5, were used to validate the ANN predictions and subsequent KBP auto-planning routine. The fully-deliverable KBP plans were developed by converting dose distribution predictions into patient-specific optimization objectives while maintaining identical target normalizations (typically PTV V100%=D98%). Plan quality improvements were quantified by the difference between SRS quality metrics (QMs): δdQM=QM(clinical)-QM(KBP). QMs of interest were: gradient measure (GM), conformity index (CI), brain V10 and V5, brainstem D0.1cc and heterogeneity index (HI). Finally, overall plan quality was judged via blinded plan comparison by SRS-specializing physicians. Results: Two clinical plans were found to be significant outliers wherein plan quality was dramatically worse than KBP. Despite indicating KBP superiority, these were removed from the QM analysis to prevent skewing the results. In the remaining cases, clinical and KBP QMs were nearly identical with modest improvements in the KBP sample: δGM=0.12±0.56mm, δCI=−0.01±0.04, Brain δV10=0.8±2.6cc, brain δV5=6.3 ±10.7cc, brainstem δD0.1cc=0.06±1.19Gy and δHI= −0.04±0.05. Ultimately, 13/17 KBP

  19. The effects of pentoxifylline on the survival of human glioma cells with continuous and intermittent stereotactic radiosurgery irradiation

    International Nuclear Information System (INIS)

    Eley, Kerry W.; Benedict, Stanley H.; Chung, Theodore D.K.; Kavanagh, Brian D.; Broaddus, William C.; Schmidt-Ullrich, Rupert K.A.; Lin, P.-S.

    2002-01-01

    Purpose: In linac-based stereotactic radiosurgery, treatment is delivered intermittently via multiple individual small radiotherapy arcs. The time lapses between the individual arcs permit greater damage repair and increased tumor cell survival in comparison with continuous irradiation. Because pentoxifylline (PTX) has been reported to prevent radiation-induced cell cycle arrest at the G2/M checkpoint, where damage repair is critically linked to cell survival, we hypothesized that PTX would exert a favorable radiosensitization effect by reducing the recovery observed during intermittent stereotactic radiosurgery. Methods and Materials: The human glioma cell line T98G was used to study the effects of continuous vs. intermittent irradiation with or without PTX. Cell cycle patterns were studied using flow cytometry. Clonogenic assays of single cells and spheroid outgrowth assays provided a quantitative measure of PTX-mediated radiosensitization. The PTX effect upon cells in low oxygen conditions was also studied in vitro after enzymatic oxygen scavenging. Results: Flow Cytometry: T98G cells exposed to both continuous and intermittent irradiation exhibit similar arrest at the G2/M checkpoint. The addition of 2 mM PTX significantly reduced the radiation-induced G2/M block in both irradiation schemes. Clonogenic Assays: The same PTX concentration applied before a continuous dose of 12 Gy, two intermittent doses of 6 Gy, or three intermittent doses of 4 Gy, all given within a 1-h interval, consistently caused radiosensitization. The drug enhancement ratios for PTX were 1.5, 2.7, and 6.0 for the continuous and two different intermittent dose schedules, respectively. Adding PTX after irradiation yielded lower enhancement ratios than pre-irradiation application. A similar pattern was observed after total doses of 4, 6, 9, or 12 Gy, as well. In low oxygen conditions, PTX was seen to have the same effects as in normoxic conditions. Spheroid Outgrowth Assays: The in vitro PTX

  20. Diffusion tractography imaging-guided frameless linear accelerator stereotactic radiosurgical thalamotomy for tremor: case report.

    Science.gov (United States)

    Kim, Won; Sharim, Justin; Tenn, Stephen; Kaprealian, Tania; Bordelon, Yvette; Agazaryan, Nzhde; Pouratian, Nader

    2018-01-01

    Essential tremor and Parkinson's disease-associated tremor are extremely prevalent within the field of movement disorders. The ventral intermediate (VIM) nucleus of the thalamus has been commonly used as both a neuromodulatory and neuroablative target for the treatment of these forms of tremor. With both deep brain stimulation and Gamma Knife radiosurgery, there is an abundance of literature regarding the surgical planning, targeting, and outcomes of these methodologies. To date, there have been no reports of frameless, linear accelerator (LINAC)-based thalomotomies for tremor. The authors report the case of a patient with tremor-dominant Parkinson's disease, with poor tremor improvement with medication, who was offered LINAC-based thalamotomy. High-resolution 0.9-mm isotropic MR images were obtained, and simulation was performed via CT with 1.5-mm contiguous slices. The VIM thalamic nucleus was determined using diffusion tensor imaging (DTI)-based segmentation on FSL using probabilistic tractography. The supplemental motor and premotor areas were the cortical target masks. The authors centered their isocenter within the region of the DTI-determined target and treated the patient with 140 Gy in a single fraction. The DTI-determined target had coordinates of 14.2 mm lateral and 8.36 mm anterior to the posterior commissure (PC), and 3 mm superior to the anterior commissure (AC)-PC line, which differed by 3.30 mm from the original target determined by anatomical considerations (15.5 mm lateral and 7 mm anterior to the PC, and 0 mm superior to the AC-PC line). There was faint radiographic evidence of lesioning at the 3-month follow-up within the target zone, which continued to consolidate on subsequent scans. The patient experienced continued right upper-extremity resting tremor improvement starting at 10 months until it was completely resolved at 22 months of follow-up. Frameless LINAC-based thalamotomy guided by DTI-based thalamic segmentation is a feasible method

  1. Characterization of an extendable multi-leaf collimator for clinical electron beams

    Science.gov (United States)

    O'Shea, Tuathan P.; Ge, Yuanyuan; Foley, Mark J.; Faddegon, Bruce A.

    2011-12-01

    An extendable x-ray multi-leaf collimator (eMLC) is investigated for collimation of electron beams on a linear accelerator. The conventional method of collimation using an electron applicator is impractical for conformal, modulated and mixed beam therapy techniques. An eMLC would allow faster, more complex treatments with potential for reduction in dose to organs-at-risk and critical structures. The add-on eMLC was modelled using the EGSnrc Monte Carlo code and validated against dose measurements at 6-21 MeV with the eMLC mounted on a Siemens Oncor linear accelerator at 71.6 and 81.6 cm source-to-collimator distances. Measurements and simulations at 8.4-18.4 cm airgaps showed agreement of 2%/2 mm. The eMLC dose profiles and percentage depth dose curves were compared with standard electron applicator parameters. The primary differences were a wider penumbra and up to 4.2% reduction in the build-up dose at 0.5 cm depth, with dose normalized on the central axis. At 90 cm source-to-surface distance (SSD)--relevant to isocentric delivery--the applicator and eMLC penumbrae agreed to 0.3 cm. The eMLC leaves, which were 7 cm thick, contributed up to 6.3% scattered electron dose at the depth of maximum dose for a 10 × 10 cm2 field, with the thick leaves effectively eliminating bremsstrahlung leakage. A Monte Carlo calculated wedge shaped dose distribution generated with all six beam energies matched across the maximum available eMLC field width demonstrated a therapeutic (80% of maximum dose) depth range of 2.1-6.8 cm. Field matching was particularly challenging at lower beam energies (6-12 MeV) due to the wider penumbrae and angular distribution of electron scattering. An eMLC isocentric electron breast boost was planned and compared with the conventional applicator fixed SSD plan, showing similar target coverage and dose to critical structures. The mean dose to the target differed by less than 2%. The low bremsstrahlung dose from the 7 cm thick MLC leaves had the added

  2. Is mask-based stereotactic head-and-neck fixation as precise as stereotactic head fixation for precision radiotherapy?

    International Nuclear Information System (INIS)

    Georg, Dietmar; Bogner, Joachim; Dieckmann, Karin; Poetter, Richard

    2006-01-01

    Background: The aim of this study was to compare setup accuracy and reproducibility of a stereotactic head and a head-and-neck fixation system, both based on thermoplastic material. Methods and Material: Ten patients were immobilized with a head and a head-and-neck fixation system (both BrainLAB, Germany). Both mask systems were modified with a custom-made mouthpiece and a strip of thermoplastic material attached to the lower part of the mask. During the first treatment session, after positioning patients using room lasers, two orthogonal portal images were taken as reference. Later on, at least five sets of orthogonal portal images were acquired for each patient. The isocentric setup accuracy was determined by comparing field edges and anatomic landmarks and the repositioning accuracy in the mask was obtained by comparing individual anatomic landmarks with respect to the metal balls, fixed on the masks. Systematic and random deviations and resulting three-dimensional (3D) vectors were calculated. Additionally, margins were derived from the systematic and random component of the isocentric setup accuracy. Finally, inter- and intraobserver variations were analyzed. Results: The systematic variation of the isocentric setup accuracy was very similar for the two mask systems, but the random variations were slightly larger for the head-and-neck system, resulting in a 0.4-mm larger 3D vector. The repositioning variations for the head mask were smaller compared with the head-and-neck mask, resulting in smaller 3D vectors for the random (∼0.4 mm) and systematic variations (∼0.6 mm). For both mask systems, a 2-mm margin can be used in lateral and anteroposterior direction, whereas in craniocaudal direction, this margin should be extended to 2.5 mm for the head mask and to 3 mm for the head-and-neck mask. The average absolute differences between two observers were within 0.5 mm, maximum deviations around 1 mm. Conclusion: Thermoplastic mask-based stereotactic head

  3. Quality assurance of a conformal treatment technique

    Energy Technology Data Exchange (ETDEWEB)

    Kroes, A P.G.; Bruinvis, I A.D.; Lanson, J H; Uiterwaal, G J [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands)

    1995-12-01

    For a parotid gland irradiation technique with a pair of oblique wedged photon beams the target coverage near the surface was investigated. The planning target volume extends to 5 millimetres under the skin; a minimum target dose of 95% is required when the dose at the centre is set to 100%. The treatment technique was simulated on a water phantom with a beam of 45 degree gantry angle, 55 degree wedge, 8 x 10 cm{sup 2} field size and the isocentre at 2 cm depth. Beam energies of 4, 6 and 8 MV were used. The dose distributions were measured in two orthogonal planes through the isocentre perpendicular to the water surface with p-type silicon diodes along lines through the isocentre every 45 degrees. Dose distributions were calculated in these planes with our 3-D planning system (U-Mplan, University of Michigan planning system), with model parameters are fitted to depth dose curves and profiles of open and wedged normally incident beams. The location of the 95% isodose was determined in five points near the surface. For 4, 6 and 8 MV the depths of the 95% isodose were 6.0, 10.3 and 11.0 mm, respectively. The depths of the 95% points of single normally incident open fields were 6.0, 9.0 and 11.5 mm, respectively. The treatment planning system (TPS) calculated the 95% isodose for the parotid technique at 5.5, 7.3 and 11.5 mm depths, for 4, 6 and 8 MV, respectively. Thus for 6 MV the 95% was 3 mm deeper than calculated by the TPS; 2 mm were caused by the inaccuracy of the open field depth dose curve fit in the build-up region. The depth near the surface of the 95% isodose for this treatment technique can be estimated from single open field depth dose curves with acceptable accuracy. This result is not obvious because the effects of the wedge and oblique incidence on the dose distribution are also involved. The TPS performed well for the 4 and 8 MV beams, but for treatments with 6 MV target under dosage could have remained undetected. (Abstract Truncated)

  4. A simple technique for treating age-related macular degeneration with external beam radiotherapy

    International Nuclear Information System (INIS)

    Roos, Daniel E.; Francis, J. Winston; Newnham, W. John

    1999-01-01

    Purpose: To develop a simple external beam photon radiotherapy technique to treat age-related macular degeneration without the need for simulation, planning computed tomography (CT) or computer dosimetry. Methods and Materials: The goal was to enable the treatment to be set up reliably on the treatment machine on Day 1 with the patient supine in a head cast without any prior planning. Using measurements of ocular globe topography from Karlsson et al. (Int J Radiat Oncol Biol Phys 1996; 33: 705-712), we chose a point 1.5 cm behind the anterior surface of the upper eyelid (ASUE) as the isocentre of a half-beam, blocked, 5.0 x 3.0-cm, angled lateral field to treat the involved eye. This would position the isocentre about 0.5 cm behind the posterior surface of the lens, and a little over 1 cm in front of the macula, according to Karlsson et al. The setup requires initial adjustment of the gantry from horizontal (to account for any asymmetry of position of the eyes), then angling 15 deg. posteriorly to avoid the contralateral eye. Finally, the couch is raised to position the isocentre 1.5 cm behind the ASUE. Results: To verify the applicability of the technique, we performed CT and computer dosimetry on the first 11 eyes so treated. Our CT measurements were in good agreement with Karlsson et al. The lens dose was < 5% and the macula was within the 95% isodose curve in each case (6-MV linac). Treatment setup time is approximately 10 min each day. The 11 patients were treated with 5 x 2.00 Gy (2 patients) or 5 x 3.00 Gy (9 patients), and subjective response on follow-up over 1 to 12 months (median 4 months) was comparable to previously reported results, with no significant acute side effects. Conclusion: Our technique is easy to set up and reliably treats the macula, with sparing of the lens and contralateral eye. It enables treatment to commence rapidly and cost-effectively without the need for simulation or CT computer planning

  5. PTV dose prescription strategies for SBRT of metastatic liver tumours

    International Nuclear Information System (INIS)

    Pooter, Jacco A. de; Wunderink, Wouter; Mendez Romero, Alejandra; Storchi, Pascal R.M.; Heijmen, Ben J.M.

    2007-01-01

    Purpose: Recently we have demonstrated that our in-house developed algorithm for automated plan generation for fully non-coplanar SBRT of liver patients (designated Cycle) yields plans that are superior to conventionally generated plans of experienced dosimetrists. Here we use Cycle in the comparison of plans with prescription isodoses of 65% or 80% of the isocentre dose. Methods: Plans were generated using CT-data of 15 previously treated patients. For each patient, both for the 65%- and the 80% strategy, Cycle was used to generate a plan with the maximum isocentre dose, D isoc , while strictly obeying a set of hard constraints for the organs at risk (OAR). Plans for the two strategies were compared using D isoc , D PTV,99% (the minimum dose delivered to 99% of the PTV), and the generalised equivalent uniform dose, gEUD PTV (a), for several values of the parameter a. Moreover, for the OARs, the distance to the constraint values was analysed. Results: The 65% strategy resulted in treatment plans with a higher D isoc (average 17.6%, range 7.6-31.1%) than the 80% strategy, at the cost of a somewhat lower D PTV,99% (average -2.0%, range -9.6% to 9.3%). On average, voxels with a dose in the 65% strategy, lower than the minimum PTV dose in the 80% strategy, were within 0.2 cm from the PTV surface. For a ≥ -10, the 65% strategy yielded on average a significantly (P PTV (a) than the 80% strategy, whereas for highly negative a-values the 80% approach was slightly better, although not significantly. Large variations between patients were observed. Generally, for the OAR the approach to the constraint levels was similar for the two strategies. Conclusion: On average, PTV dose delivery is superior with the 65% strategy. However, apart from the isocentre dose, for each applied PTV dose parameter at least one patient would have been better off with the 80% dose prescription strategy

  6. Monolithic silicon photonics in a sub-100nm SOI CMOS microprocessor foundry: progress from devices to systems

    Science.gov (United States)

    Popović, Miloš A.; Wade, Mark T.; Orcutt, Jason S.; Shainline, Jeffrey M.; Sun, Chen; Georgas, Michael; Moss, Benjamin; Kumar, Rajesh; Alloatti, Luca; Pavanello, Fabio; Chen, Yu-Hsin; Nammari, Kareem; Notaros, Jelena; Atabaki, Amir; Leu, Jonathan; Stojanović, Vladimir; Ram, Rajeev J.

    2015-02-01

    We review recent progress of an effort led by the Stojanović (UC Berkeley), Ram (MIT) and Popović (CU Boulder) research groups to enable the design of photonic devices, and complete on-chip electro-optic systems and interfaces, directly in standard microelectronics CMOS processes in a microprocessor foundry, with no in-foundry process modifications. This approach allows tight and large-scale monolithic integration of silicon photonics with state-of-the-art (sub-100nm-node) microelectronics, here a 45nm SOI CMOS process. It enables natural scale-up to manufacturing, and rapid advances in device design due to process repeatability. The initial driver application was addressing the processor-to-memory communication energy bottleneck. Device results include 5Gbps modulators based on an interleaved junction that take advantage of the high resolution of the sub-100nm CMOS process. We demonstrate operation at 5fJ/bit with 1.5dB insertion loss and 8dB extinction ratio. We also demonstrate the first infrared detectors in a zero-change CMOS process, using absorption in transistor source/drain SiGe stressors. Subsystems described include the first monolithically integrated electronic-photonic transmitter on chip (modulator+driver) with 20-70fJ/bit wall plug energy/bit (2-3.5Gbps), to our knowledge the lowest transmitter energy demonstrated to date. We also demonstrate native-process infrared receivers at 220fJ/bit (5Gbps). These are encouraging signs for the prospects of monolithic electronics-photonics integration. Beyond processor-to-memory interconnects, our approach to photonics as a "More-than- Moore" technology inside advanced CMOS promises to enable VLSI electronic-photonic chip platforms tailored to a vast array of emerging applications, from optical and acoustic sensing, high-speed signal processing, RF and optical metrology and clocks, through to analog computation and quantum technology.

  7. Nonrelativistic quantum electrodynamic approach to photoemission theory

    International Nuclear Information System (INIS)

    Fujikawa, Takashi; Arai, Hiroko

    2005-01-01

    A new nonrelativistic many-body theory to analyze X-ray photoelectron spectroscopy (XPS) spectra has been developed on the basis of quantum electrodynamic (QED) Keldysh Green's function approach. To obtain XPS current density we calculate electron Green's function g which partly includes electron-photon interactions. We first separate longitudinal and transverse parts of these Green's functions in the Coulomb gauge. The transverse electron selfenergy describes the electron-photon interaction, whereas the longitudinal electron selfenergy describes the electron-electron interaction. We derive the QED Hedin's equation from which we obtain systematic skeleton expansion in the power series of the screened Coulomb interaction W and the photon Green's function D kl . We show the present theory provides a sound theoretical tool to study complicated many-body processes such as the electron propagation damping, intrinsic, extrinsic losses and their interference, and furthermore, resonant photoemission processes. We have also found the importance of the mixed photon Green's functions D 0k and D k0 which have been supposed to be unimportant for the XPS analyses. They, however, directly describe the radiation field screening. In this work, photon field screening effects are discussed in one-step theory, where the electron-photon interaction operator Δ is proved to be replaced by ε -1 Δ beyond linear approximation. Beyond free photon Green's function approximation, photon scatterings from the electron density are incorporated within the present QED theory. These photon field effects can directly describe the microscopic photon field spatial variation specific to near the surface region and nanoparticle systems

  8. Elsa: an infrared free electron laser

    International Nuclear Information System (INIS)

    Guimbal, P.; Chaix, P.

    1998-01-01

    Since the first experiments, twenty years ago, free-electron lasers (FEL) have known a strong development because of their promise: broadband tunability from X-rays to microwaves and high (peak or average) power, limited only by technological issues. ELSA has been designed as a research tool to investigate the physics of high-power FELs. After a brief introduction of the FEL field of research, we point out the unique characteristics of ELSA and why it is a valuable tool for the study of FEL interaction in the strong electron-photon coupling. The main experimental results are reviewed. We conclude on the concept of Two-Frequency-Wiggler. (author)

  9. Time evolution of absorption process in nonlinear metallic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Hatef, Ali [Department of Physics and Astronomy, University of Western Ontario, London (Canada)

    2009-05-15

    The time evolution of the absorption coefficient in metallic photonic crystals has been studied numerically. These crystals are made from metallic spheres which are arranged periodically in air. The refractive index of the metallic spheres depends on the plasma frequency. Probe and pump fields are applied to monitor the absorption process. Ensembles of three-level particles are embedded in the crystal. Nanoparticles are interacting with the metallic crystals via the electron-photon interaction. It is found that when the resonance states lie away from the band edges system goes to transparent state. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. A new approach to modelling radiation noise in CCD's

    International Nuclear Information System (INIS)

    Chugg, A.; Hopkinson, G.

    1998-01-01

    The energy depositions reported by Monte Carlo electron-photon irradiation transport codes are subject to a random error due to the finite number of particle histories used to generate the results. These statistical variations, normally a nuisance, may also be identified with the real radiation noise effects experienced by CCD pixels in persistent radiation environments. This paper explores the practicability of such radiation noise modelling by applying the ACCEPT code from the ITS suite to the case of a shielded CCD exposed to an electron flux. The results are compared with those obtained in a subsequent electron irradiation of the CCD by a Van de Graaff accelerator

  11. Image-converter streak cameras with very high gain

    International Nuclear Information System (INIS)

    1975-01-01

    A new camera is described with slit scanning and very high photonic gain (G=5000). Development of the technology of tubes and microchannel plates has enabled integration of such an amplifying element in an image converter tube which does away with the couplings and the intermediary electron-photon-electron conversions of the classical converter systems having external amplification. It is thus possible to obtain equal or superior performance while retaining considerable gain for the camera, great compactness, great flexibility in use, and easy handling. (author)

  12. Relativistic quantum dynamics in strong fields: Photon emission from heavy, few-electron ions

    International Nuclear Information System (INIS)

    Fritzsche, S.; Stoehlker, T.

    2005-03-01

    Recent progress in the study of the photon emission from highly-charged heavy ions is reviewed. These investigations show that high-Z ions provide a unique tool for improving the understanding of the electron-electron and electron-photon interaction in the presence of strong fields. Apart from the bound-state transitions, which are accurately described in the framework of quantum electrodynamics, much information has been obtained also from the radiative capture of (quasi-) free electrons by high-Z ions. Many features in the observed spectra hereby confirm the inherently relativistic behavior of even the simplest compound quantum systems in nature. (orig.)

  13. The elementary process of Bremsstrahlung

    CERN Document Server

    Haug, Eberhard

    2004-01-01

    This book deals with the theory and experiment of the elementary process of bremsstrahlung, where photons are detected in coincidence with decelerated outgoing electrons. Such experiments allow for a more stringent check of the theoretical work. The main emphasis is laid on electron-atom bremsstrahlung and electron-electron bremsstrahlung, but further bremsstrahlung processes are also dealt with. In the theoretical parts, triply differential cross sections are derived in various approximations, including electron spin and photon-polarization. In the experimental sections, electron-photon coinc

  14. First-principles electron dynamics control simulation of diamond under femtosecond laser pulse train irradiation

    International Nuclear Information System (INIS)

    Wang Cong; Jiang Lan; Wang Feng; Li Xin; Yuan Yanping; Xiao Hai; Tsai, Hai-Lung; Lu Yongfeng

    2012-01-01

    A real-time and real-space time-dependent density functional is applied to simulate the nonlinear electron-photon interactions during shaped femtosecond laser pulse train ablation of diamond. Effects of the key pulse train parameters such as the pulse separation, spatial/temporal pulse energy distribution and pulse number per train on the electron excitation and energy absorption are discussed. The calculations show that photon-electron interactions and transient localized electron dynamics can be controlled including photon absorption, electron excitation, electron density, and free electron distribution by the ultrafast laser pulse train. (paper)

  15. Detectors for particle radiation. 2. rev. ed.

    International Nuclear Information System (INIS)

    Kleinknecht, K.

    1987-01-01

    This book is a description of the set-up and mode of action of detectors for charged particles and gamma radiation for students of physics, as well as for experimental physicists and engineers in research and industry: Ionization chamber, proportional counter, semiconductor counter; proportional chamber, drift chamber, bubble chamber, spark chamber, photomultiplier, laser ionization, silicion strip detector; Cherenkov counter, transition radiation detector; electron-photon-cascade counter, hadron calorimeter; magnetic spectrometer; applications in nuclear medicine, geophysics, space travel, atom physics, nuclear physics, and high-energy physics. With 149 figs., 20 tabs [de

  16. Phase-I Trigger Readout Electronics Upgrade for the ATLAS Liquid-Argon Calorimeters

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00452211; The ATLAS collaboration

    2017-01-01

    The upgrade of the Large Hadron Collider (LHC) scheduled for the Long Shut-down period of 2019-2020 (LS2), referred to as Phase-I upgrade, will increase the instantaneous luminosity to about three times the design value. Since the current ATLAS trigger system does not allow sucient increase of the trigger rate, an improvement of the trigger system is required. The Liquid Argon (LAr) Calorimeter read-out will therefore be modi ed to use digital trigger signals with a higher spatial granularity in order to improve the identi cation effciencies of electrons, photons, tau, jets and missing energy, at high background rejection rates at the Level-1 trigger.

  17. Optical waveguiding and applied photonics technological aspects, experimental issue approaches and measurements

    CERN Document Server

    Massaro, Alessandro

    2012-01-01

    Optoelectronics--technology based on applications light such as micro/nano quantum electronics, photonic devices, laser for measurements and detection--has become an important field of research. Many applications and physical problems concerning optoelectronics are analyzed in Optical Waveguiding and Applied Photonics.The book is organized in order to explain how to implement innovative sensors starting from basic physical principles. Applications such as cavity resonance, filtering, tactile sensors, robotic sensor, oil spill detection, small antennas and experimental setups using lasers are a

  18. Influence of time-periodic potentials on electronic transport in double-well structure

    International Nuclear Information System (INIS)

    Chun-Lei, Li; Yan, Xu

    2010-01-01

    Within the framework of the Floquet theorem, we have investigated single-electron photon-assisted tunneling in a double-well system using the transfer matrix technique. The transmission probability displays satellite peaks on both sides of the main resonance peaks and these satellite peaks originate from emission or absorption photons. The single-electron resonance tunneling can be controlled through changing the applied harmonically potential positions, such as driven potential in wells, in barriers, or in whole double-well systems. This advantage should be useful in the optimization of the parameters of a transmission device. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. A general search for new phenomena with the ATLAS detector in pp collisions at √ s = 7TeV

    International Nuclear Information System (INIS)

    Amoroso, S.

    2013-01-01

    We present results of a Model-Independent General Search for new physics in proton-proton collisions at √ s = 7TeV. Data collected by the ATLAS experiment in 2011, for a total integrated luminosity of 4.7 fb −1 has been used. All event topologies involving isolated electrons, photons, muons, jets, b-jets and missing transverse momentum are subdivided according to their final states into exclusive classes. A search algorithm is then used to scan all classes for deviations from the Monte Carlo simulated background in the distribution of the scalar sum of transverse momenta. No excess over the Standard Model expectation is observed.

  20. The ATLAS Liquid Argon Calorimeters At The Dawn Of LHC Run-2

    CERN Document Server

    Camincher, Clement; The ATLAS collaboration

    2015-01-01

    The Liquid Argon Calorimeters are key sub-detectors of ATLAS. They are essential to detect and measure the properties of electrons, photons and are also crucial for jets and missing transverse energy measurements. During the LHC shutdown in 2013-2014, the hardware and the software have been optimized to improve their reliability. The first collisions allows to assess the performance of the detector in the LHC Run-2 real conditions. In view of the next LHC Run in 2020, an upgrade of the level-1 trigger system is also under test. A status at the restart of the LHC Run-2 is presented in this document.

  1. Transition effect of extensive air showers in thick scintillators

    International Nuclear Information System (INIS)

    Lidvanskij, A.S.; Navarra, Dzh.; Chernyaev, A.V.

    1985-01-01

    Transition effect of extensive air showers has been measured by means of the ''Kover'' facility of the Baksan neutrino laboratory. The transition effect represents the ratio of ''scintillation'' particle density detected with detectors and particle density under the facility concrete roof (21 gxcm -2 ). Measurement results are compared with data obtained by means of the program of electron-photon cascade gaming. Good agreement of experimental and calculational data has been obtained. It follows from the data in the paper that the transition effect for one scintillator in the absence of roof can be produced by the gaming rather reliably

  2. EGS4 in '94: A decade of enhancements

    International Nuclear Information System (INIS)

    Nelson, W.R.; Bielajew, A.F.; Rogers, D.W.O.

    1994-01-01

    This paper presents an overview of the developments made to the EGS4 code over the past decade. This code is a Monte Carlo code developed to study electron-photon transport properties. It is widely used, in particular in the medical physics field, it has been updated, expanded, benchmarked, and applied to a wide array of problems. The paper covers precursors to this code, a basic snapshop of its physics and calculation methods, and an overview of how it has been expanded during the past decade

  3. Test calculations of photoneutrons emission from surface of uranium sphere irradiated by 28 MeV electrons

    International Nuclear Information System (INIS)

    Blokhin, A.I.; Degtyarev, I.I.

    2002-01-01

    In this paper the results of physical verification for the BOFOD photonuclear data files are reported, available for the uranium isotopes U 235 , U 238 . These results were compared with calculated data by the parameterization driven model of photonuclear reaction and experimental data. Experimental data of photoneutron yields from surface of uranium sphere irradiated by 28 MeV electrons are used for a verification. Both calculations have been carried out with the RTS and T general purpose Monte Carlo code with detailed electron-photon-nucleon transport simulation using the ENDF/B-VI and EPDL evaluated data libraries

  4. Performance of the CMS Level-1 Trigger during Commissioning with Cosmic Ray Muons and LHC beams

    CERN Document Server

    Chatrchyan, S; Sirunyan, A M; Adam, W; Arnold, B; Bergauer, H; Bergauer, T; Dragicevic, M; Eichberger, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kastner, K; Krammer, M; Liko, D; Magrans de Abril, I; Mikulec, I; Mittermayr, F; Neuherz, B; Oberegger, M; Padrta, M; Pernicka, M; Rohringer, H; Schmid, S; Schöfbeck, R; Schreiner, T; Stark, R; Steininger, H; Strauss, J; Taurok, A; Teischinger, F; Themel, T; Uhl, D; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C E; Chekhovsky, V; Dvornikov, O; Emeliantchik, I; Litomin, A; Makarenko, V; Marfin, I; Mossolov, V; Shumeiko, N; Solin, A; Stefanovitch, R; Suarez Gonzalez, J; Tikhonov, A; Fedorov, A; Karneyeu, A; Korzhik, M; Panov, V; Zuyeuski, R; Kuchinsky, P; Beaumont, W; Benucci, L; Cardaci, M; De Wolf, E A; Delmeire, E; Druzhkin, D; Hashemi, M; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Adler, V; Beauceron, S; Blyweert, S; D'Hondt, J; De Weirdt, S; Devroede, O; Heyninck, J; Kalogeropoulos, A; Maes, J; Maes, M; Mozer, M U; Tavernier, S; Van Doninck, W; Van Mulders, P; Villella, I; Bouhali, O; Chabert, E C; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Elgammal, S; Gay, A P R; Hammad, G H; Marage, P E; Rugovac, S; Vander Velde, C; Vanlaer, P; Wickens, J; Grunewald, M; Klein, B; Marinov, A; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Basegmez, S; Bruno, G; Caudron, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Lemaitre, V; Militaru, O; Ovyn, S; Piotrzkowski, K; Quertenmont, L; Schul, N; Beliy, N; Daubie, E; Alves, G A; Pol, M E; Souza, M H G; Carvalho, W; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Oguri, V; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Fernandez Perez Tomei, T R; Ferreira Dias, M A; Gregores, E M; Novaes, S F; Abadjiev, K; Anguelov, T; Damgov, J; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Stoykova, S; Sultanov, G; Trayanov, R; Vankov, I; Dimitrov, A; Dyulendarova, M; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Toteva, Z; Chen, G M; Chen, H S; Guan, W; Jiang, C H; Liang, D; Liu, B; Meng, X; Tao, J; Wang, J; Wang, Z; Xue, Z; Zhang, Z; Ban, Y; Cai, J; Ge, Y; Guo, S; Hu, Z; Mao, Y; Qian, S J; Teng, H; Zhu, B; Avila, C; Baquero Ruiz, M; Carrillo Montoya, C A; Gomez, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Reyes Romero, D; Sanabria, J C; Godinovic, N; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Fereos, R; Galanti, M; Mousa, J; Papadakis, A; Ptochos, F; Razis, P A; Tsiakkouri, D; Zinonos, Z; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Anttila, E; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; 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Yang, Y; Zhang, L; Zhu, K; Zhu, R Y; Akgun, B; Carroll, R; Ferguson, T; Jang, D W; Jun, S Y; Paulini, M; Russ, J; Terentyev, N; Vogel, H; Vorobiev, I; Cumalat, J P; Dinardo, M E; Drell, B R; Ford, W T; Heyburn, B; Luiggi Lopez, E; Nauenberg, U; Stenson, K; Ulmer, K; Wagner, S R; Zang, S L; Agostino, L; Alexander, J; Blekman, F; Cassel, D; Chatterjee, A; Das, S; Gibbons, L K; Heltsley, B; Hopkins, W; Khukhunaishvili, A; Kreis, B; Kuznetsov, V; Patterson, J R; Puigh, D; Ryd, A; Shi, X; Stroiney, S; Sun, W; Teo, W D; Thom, J; Vaughan, J; Weng, Y; Wittich, P; Beetz, C P; Cirino, G; Sanzeni, C; Winn, D; Abdullin, S; Afaq, M A; Albrow, M; Ananthan, B; Apollinari, G; Atac, M; Badgett, W; Bagby, L; Bakken, J A; Baldin, B; Banerjee, S; Banicz, K; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Biery, K; Binkley, M; Bloch, I; Borcherding, F; Brett, A M; Burkett, K; Butler, J N; Chetluru, V; Cheung, H W K; Chlebana, F; Churin, I; Cihangir, S; Crawford, M; Dagenhart, W; Demarteau, M; Derylo, G; Dykstra, D; Eartly, D P; Elias, J E; Elvira, V D; Evans, D; Feng, L; Fischler, M; Fisk, I; Foulkes, S; Freeman, J; Gartung, P; Gottschalk, E; Grassi, T; Green, D; Guo, Y; Gutsche, O; Hahn, A; Hanlon, J; Harris, R M; Holzman, B; Howell, J; Hufnagel, D; James, E; Jensen, H; Johnson, M; Jones, C D; Joshi, U; Juska, E; Kaiser, J; Klima, B; Kossiakov, S; Kousouris, K; Kwan, S; Lei, C M; Limon, P; Lopez Perez, J A; Los, S; Lueking, L; Lukhanin, G; Lusin, S; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Moccia, S; Mommsen, R; Mrenna, S; Muhammad, A S; Newman-Holmes, C; Noeding, C; O'Dell, V; Prokofyev, O; Rivera, R; Rivetta, C H; Ronzhin, A; Rossman, P; Ryu, S; Sekhri, V; Sexton-Kennedy, E; Sfiligoi, I; Sharma, S; Shaw, T M; Shpakov, D; Skup, E; Smith, R P; Soha, A; Spalding, W J; Spiegel, L; Suzuki, I; Tan, P; Tanenbaum, W; Tkaczyk, S; Trentadue, R; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wicklund, E; Wu, W; Yarba, J; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Barashko, V; Bourilkov, D; Chen, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fu, Y; Furic, I K; Gartner, J; Holmes, D; Kim, B; Klimenko, S; Konigsberg, J; Korytov, A; Kotov, K; Kropivnitskaya, A; Kypreos, T; Madorsky, A; Matchev, K; Mitselmakher, G; Pakhotin, Y; Piedra Gomez, J; Prescott, C; Rapsevicius, V; Remington, R; Schmitt, M; Scurlock, B; Wang, D; Yelton, J; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, T; Askew, A; Baer, H; Bertoldi, M; Chen, J; Dharmaratna, W G D; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prettner, E; Prosper, H; Sekmen, S; Baarmand, M M; Guragain, S; Hohlmann, M; Kalakhety, H; Mermerkaya, H; Ralich, R; Vodopiyanov, I; Abelev, B; Adams, M R; Anghel, I M; Apanasevich, L; Bazterra, V E; Betts, R R; Callner, J; Castro, M A; Cavanaugh, R; Dragoiu, C; Garcia-Solis, E J; Gerber, C E; Hofman, D J; Khalatian, S; Mironov, C; Shabalina, E; Smoron, A; Varelas, N; Akgun, U; Albayrak, E A; Ayan, A S; Bilki, B; Briggs, R; Cankocak, K; Chung, K; Clarida, W; Debbins, P; Duru, F; Ingram, F D; Lae, C K; McCliment, E; Merlo, J P; Mestvirishvili, A; Miller, M J; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Parsons, J; Schmidt, I; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Chien, C Y; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Zhang, Y; Baringer, P; Bean, A; Grachov, O; Murray, M; Radicci, V; Sanders, S; Wood, J S; Zhukova, V; Bandurin, D; Bolton, T; Kaadze, K; Liu, A; Maravin, Y; Onoprienko, D; Svintradze, I; Wan, Z; Gronberg, J; Hollar, J; Lange, D; Wright, D; Baden, D; Bard, R; Boutemeur, M; Eno, S C; Ferencek, D; Hadley, N J; Kellogg, R G; Kirn, M; Kunori, S; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Toole, T; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; D'Enterria, D; Everaerts, P; Gomez Ceballos, G; Hahn, K A; Harris, P; Jaditz, S; Kim, Y; Klute, M; Lee, Y J; Li, W; Loizides, C; Ma, T; Miller, M; Nahn, S; Paus, C; Roland, C; Roland, G; Rudolph, M; Stephans, G; Sumorok, K; Sung, K; Vaurynovich, S; Wenger, E A; Wyslouch, B; Xie, S; Yilmaz, Y; Yoon, A S; Bailleux, D; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dolgopolov, A; Dudero, P R; Egeland, R; Franzoni, G; Haupt, J; Inyakin, A; Klapoetke, K; Kubota, Y; Mans, J; Mirman, N; Petyt, D; Rekovic, V; Rusack, R; Schroeder, M; Singovsky, A; Zhang, J; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Sonnek, P; Summers, D; Bloom, K; Bockelman, B; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Lundstedt, C; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Iashvili, I; Kharchilava, A; Kumar, A; Smith, K; Strang, M; Alverson, G; Barberis, E; Boeriu, O; Eulisse, G; Govi, G; McCauley, T; Musienko, Y; Muzaffar, S; Osborne, I; Paul, T; Reucroft, S; Swain, J; Taylor, L; Tuura, L; Anastassov, A; Gobbi, B; Kubik, A; Ofierzynski, R A; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolberg, T; Lannon, K; Lynch, S; Marinelli, N; Morse, D M; Ruchti, R; Slaunwhite, J; Warchol, J; Wayne, M; Bylsma, B; Durkin, L S; Gilmore, J; Gu, J; Killewald, P; Ling, T Y; Williams, G; Adam, N; Berry, E; Elmer, P; Garmash, A; Gerbaudo, D; Halyo, V; Hunt, A; Jones, J; Laird, E; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Stickland, D; Tully, C; Werner, J S; Wildish, T; Xie, Z; Zuranski, A; Acosta, J G; Bonnett Del Alamo, M; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Santacruz, N; Zatzerklyany, A; Alagoz, E; Antillon, E; Barnes, V E; Bolla, G; Bortoletto, D; Everett, A; Garfinkel, A F; Gecse, Z; Gutay, L; Ippolito, N; Jones, M; Koybasi, O; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Sedov, A; Shipsey, I; Yoo, H D; Zheng, Y; Jindal, P; Parashar, N; Cuplov, V; Ecklund, K M; Geurts, F J M; Liu, J H; Maronde, D; Matveev, M; Padley, B P; Redjimi, R; Roberts, J; Sabbatini, L; Tumanov, A; Betchart, B; Bodek, A; Budd, H; Chung, Y S; de Barbaro, P; Demina, R; Flacher, H; Gotra, Y; Harel, A; Korjenevski, S; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Demortier, L; Goulianos, K; Hatakeyama, K; Lungu, G; Mesropian, C; Yan, M; Atramentov, O; Bartz, E; Gershtein, Y; Halkiadakis, E; Hits, D; Lath, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Watts, T L; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Aurisano, A; Eusebi, R; Golyash, A; Gurrola, A; Kamon, T; Nguyen, C N; Pivarski, J; Safonov, A; Sengupta, S; Toback, D; Weinberger, M; Akchurin, N; Berntzon, L; Gumus, K; Jeong, C; Kim, H; Lee, S W; Popescu, S; Roh, Y; Sill, A; Volobouev, I; Washington, E; Wigmans, R; Yazgan, E; Engh, D; Florez, C; Johns, W; Pathak, S; Sheldon, P; Andelin, D; Arenton, M W; Balazs, M; Boutle, S; Buehler, M; Conetti, S; Cox, B; Hirosky, R; Ledovskoy, A; Neu, C; Phillips II, D; Ronquest, M; Yohay, R; Gollapinni, S; Gunthoti, K; Harr, R; Karchin, P E; Mattson, M; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Crotty, I; Dasu, S; Dutta, S; Efron, J; Feyzi, F; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Jaworski, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Magrans de Abril, M; Mohapatra, A; Ott, G; Polese, G; Reeder, D; Savin, A; Smith, W H; Sourkov, A; Swanson, J; Weinberg, M; Wenman, D; Wensveen, M; White, A

    2010-01-01

    The CMS Level-1 trigger was used to select cosmic ray muons and LHC beam events during data-taking runs in 2008, and to estimate the level of detector noise. This paper describes the trigger components used, the algorithms that were executed, and the trigger synchronisation. Using data from extended cosmic ray runs, the muon, electron/photon, and jet triggers have been validated, and their performance evaluated. Efficiencies were found to be high, resolutions were found to be good, and rates as expected.

  5. Lepton and photon performance at ATLAS and CMS

    CERN Document Server

    Lesage, Arthur; The ATLAS collaboration

    2017-01-01

    These proceedings report on lepton and photon performance results obtained using data recorded in 2015 and 2016 at the LHC by the two experiments ATLAS and CMS. For each particle (electrons, photons and muons), the reconstruction and identification efficiencies are presented for the two experiments together with the isolation studies. Results concerning the electron and photon energy calibration as well as the muon momentum scale and resolution are also reported. Despite more challenging pile-up conditions with respect to Run 1, the two experiments achieved impressive performance in early Run 2.

  6. Experimental-theoretical comparisons of 1/sup 1/S. -->. 3/sup 1/P differential magnetic sublevel cross sections for electron-helium scattering at 80 and 100 eV

    Energy Technology Data Exchange (ETDEWEB)

    Chutjian, A [Jet Propulsion Lab., Pasadena, Calif. (USA)

    1976-07-11

    Experimental normalized absolute differential cross sections (DCS) for the excitation 1/sup 1/S ..-->.. 3/sup 1/P in helium are reported at incident electron energies of 80 and 100 eV, and at scattering angles between 7/sup 0/ and 135/sup 0/. The measurements are combined with results of recent electron-photon coincidence studies, and absolute DCS for the excitation of the magnetic sublevels 3/sup 1/P/sub 0/ and 3/sup 1/Psub(+-1) are obtained. These experimental sublevel cross sections, and their sum, are compared with results of recent calculations in the multichannel eikonal and distorted-wave polarized-orbital theories.

  7. Control, Test and Monitoring Software Framework for the ATLAS Level-1 Calorimeter Trigger

    CERN Document Server

    Achenbach, R; Aharrouche, M; Andrei, V; Åsman, B; Barnett, B M; Bauss, B; Bendel, M; Bohm, C; Booth, J R A; Bracinik, J; Brawn, I P; Charlton, D G; Childers, J T; Collins, N J; Curtis, C J; Davis, A O; Eckweiler, S; Eisenhandler, E F; Faulkner, P J W; Fleckner, J; Föhlisch, F; Gee, C N P; Gillman, A R; Goringer, C; Groll, M; Hadley, D R; Hanke, P; Hellman, S; Hidvegi, A; Hillier, S J; Johansen, M; Kluge, E E; Kühl, T; Landon, M; Lendermann, V; Lilley, J N; Mahboubi, K; Mahout, G; Meier, K; Middleton, R P; Moa, T; Morris, J D; Müller, F; Neusiedl, A; Ohm, C; Oltmann, B; Perera, V J O; Prieur, D P F; Qian, W; Rieke, S; Rühr, F; Sankey, D P C; Schäfer, U; Schmitt, K; Schultz-Coulon, H C; Silverstein, S; Sjölin, J; Staley, R J; Stamen, R; Stockton, M C; Tan, C L A; Tapprogge, S; Thomas, J P; Thompson, P D; Watkins, P M; Watson, A; Weber, P; Wessels, M; Wildt, M

    2008-01-01

    The ATLAS first-level calorimeter trigger is a hardware-based system designed to identify high-pT jets, electron/photon and tau candidates and to measure total and missing ET in the ATLAS calorimeters. The complete trigger system consists of over 300 customdesignedVME modules of varying complexity. These modules are based around FPGAs or ASICs with many configurable parameters, both to initialize the system with correct calibrations and timings and to allow flexibility in the trigger algorithms. The control, testing and monitoring of these modules requires a comprehensive, but well-designed and modular, software framework, which we will describe in this paper.

  8. Beta/gamma test problems for ITS

    International Nuclear Information System (INIS)

    Mei, G.T.

    1993-01-01

    The Integrated Tiger Series of Coupled Electron/Photon Monte Carlo Transport Codes (ITS 3.0, PC Version) was used at Oak Ridge National Laboratory (ORNL) to compare with and extend the experimental findings of the beta/gamma response of selected health physics instruments. In order to assure that ITS gives correct results, several beta/gamma problems have been tested. ITS was used to simulate these problems numerically, and results for each were compared to the problem's experimental or analytical results. ITS successfully predicted the experimental or analytical results of all tested problems within the statistical uncertainty inherent in the Monte Carlo method

  9. SASP. Contributions to the 13. Symposium on atomic and surface physics and related topics

    International Nuclear Information System (INIS)

    Scheier, P.; Maerk, T.

    2002-01-01

    The XIII symposium on Atomic and Surface Physics and related Topics (SASP) is devoted to cover the research of interactions between ions, electrons, photons, atoms, molecules and clusters and their interaction with surfaces. This year there was a special session dedicated to proton transfer reaction mass spectrometry covering its applications in different fields and a mini symposium on the radiation action on bio-molecules such as uracil. The contributions included in the proceeding correspond to invited lectures and poster sessions, consisting of short and extended abstracts as well as short articles. (nevyjel)

  10. Measurements of lambda and chi parameters for excitation of the 21P state of helium at 80 eV

    International Nuclear Information System (INIS)

    Slevin, J.; Porter, H.Q.; Eminyan, M.; Defrance, A.; Vassilev, G.

    1980-01-01

    Electron-photon angular correlations have been measured for excitation of the 2 1 P state of helium at an incident energy of 80 eV over the range 10-115 0 of electron scattering angles. analysis of the data yields values for the alignment and orientation parameters lambda and |chi| which are in excellent agreement with data of Hollywood et al (J. Phys. B.; 12: 819 (1979)) but the data for lambda are in marked disagreement with the results of Steph and Golden (preprint. Univ. of Oklahoma (1979)) at electron scattering angles thetasub(c)> 70 0 . (author)

  11. Current correlations for the transport of interacting electrons through parallel quantum dots in a photon cavity

    Science.gov (United States)

    Gudmundsson, Vidar; Abdullah, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

    2018-06-01

    We calculate the current correlations for the steady-state electron transport through multi-level parallel quantum dots embedded in a short quantum wire, that is placed in a non-perfect photon cavity. We account for the electron-electron Coulomb interaction, and the para- and diamagnetic electron-photon interactions with a stepwise scheme of configuration interactions and truncation of the many-body Fock spaces. In the spectral density of the temporal current-current correlations we identify all the transitions, radiative and non-radiative, active in the system in order to maintain the steady state. We observe strong signs of two types of Rabi oscillations.

  12. Interpretation of the radioactive background observed in the OSO-7 gamma ray monitor

    International Nuclear Information System (INIS)

    Dyer, C.S.

    1975-01-01

    Application of a spallation activation calculation to the OSO-7 gamma-ray monitor background shows that major line features and about 30% of the continuum can be understood as activation of the central detector crystal by trapped protons. Weaker line features arise from activation of materials unshielded by the anticoincidence cup, while the remaining continuum and annihilation line would seem to come largely continuum and annihilation line would seem to come largely from electron-photon cascades originating in the spacecraft. (orig.) [de

  13. Pseudospins and Topological Effects of Phonons in a Kekulé Lattice

    Science.gov (United States)

    Liu, Yizhou; Lian, Chao-Sheng; Li, Yang; Xu, Yong; Duan, Wenhui

    2017-12-01

    The search for exotic topological effects of phonons has attracted enormous interest for both fundamental science and practical applications. By studying phonons in a Kekulé lattice, we find a new type of pseudospin characterized by quantized Berry phases and pseudoangular momenta, which introduces various novel topological effects, including topologically protected pseudospin-polarized interface states and a phonon pseudospin Hall effect. We further demonstrate a pseudospin-contrasting optical selection rule and a pseudospin Zeeman effect, giving a complete generation-manipulation-detection paradigm of the phonon pseudospin. The pseudospin and topology-related physics revealed for phonons is general and applicable for electrons, photons, and other particles.

  14. Report from the ZEUS Collaboration at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Weizmann Institute of Science, Rehovot (Israel)

    1994-12-01

    This is a short overview of the results obtained by the ZEUS Collaboration with data collected during HERA`s first year and corresponding to an integrated luminosity of 25 nb{sup {minus}1}. Included are the measurement of the total, partial, and {rho} photoproduction cross sections, a study of high mass diffractive photoproduction, new results from hard photoproduction where a clear signal of a direct photon contribution has been established, the measurement of the photon structure function F{sub 2}, and first results on diffractive dissociation of the virtual photon in the deep inelastic electron photon scattering. Limits on leptoquarks and excited electrons are also presented.

  15. Calculation of energy and angular distributions of the bremsstrahlung of 10 MeV electrons bombarding a thick tungsten target

    International Nuclear Information System (INIS)

    Tsovbun, V.I.

    1977-01-01

    Computer calculations have been performed to extend the data available on energy and angular distribution of the 10 MeV electron bremsrahlung into a higher angle region. The ETRAN-16D program developed by R.G.Berger for calculation of electron-photon cascades passing through matter using computers IBM-360 and UNIVAC-1108 was modified to operate with the CDC-6500 computer. A brief summary of the program is provided. An angular distribution of the bremsstrahlung dose absorbed in the air has been also calculated. The results extended into the 90-180 deg region can be used to calculate the biological shield of electron accelerators

  16. Monte Carlo 20 and 45 MeV Bremsstrahlung and dose-reduction calculations

    Energy Technology Data Exchange (ETDEWEB)

    Goosman, D.R.

    1984-08-14

    The SANDYL electron-photon coupled Monte Carlo code has been compared with previously published experimental bremsstrahlung data at 20.9 MeV electron energy. The code was then used to calculate forward-directed spectra, angular distributions and dose-reduction factors for three practical configurations. These are: 20 MeV electrons incident on 1 mm of W + 59 mm of Be, 45 MeV electrons of 1 mm of W and 45 MeV electrons on 1 mm of W + 147 mm of Be. The application of these results to flash radiography is discussed. 7 references, 12 figures, 1 table.

  17. Monte Carlo 20 and 45 MeV Bremsstrahlung and dose-reduction calculations

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1984-01-01

    The SANDYL electron-photon coupled Monte Carlo code has been compared with previously published experimental bremsstrahlung data at 20.9 MeV electron energy. The code was then used to calculate forward-directed spectra, angular distributions and dose-reduction factors for three practical configurations. These are: 20 MeV electrons incident on 1 mm of W + 59 mm of Be, 45 MeV electrons of 1 mm of W and 45 MeV electrons on 1 mm of W + 147 mm of Be. The application of these results to flash radiography is discussed. 7 references, 12 figures, 1 table

  18. Piezoelectric ZnO nanostructure for energy harvesting

    CERN Document Server

    Leprince-Wang, Yamin

    2015-01-01

    Over the past decade, ZnO as an important II-VI semiconductor has attracted much attention within the scientific community over the world owing to its numerous unique and prosperous properties. This material, considered as a "future material", especially in nanostructural format, has aroused many interesting research works due to its large range of applications in electronics, photonics, acoustics, energy and sensing. The bio-compatibility, piezoelectricity & low cost fabrication make ZnO nanostructure a very promising material for energy harvesting.

  19. Activities of the JILA Atomic Collisions Cross Sections Data Center

    International Nuclear Information System (INIS)

    Gallagher, J.W.

    1983-01-01

    The JILA Atomic Collisions Cross Sections Data Center compiles, critically evaluates, and reviews cross sections and rates for low energy (<100 keV) collisions of electrons, photons, and heavy particles with atoms, ions, and simple molecules. Reports are prepared which provide easily accessible recommended data with error limits, list the fundamental literature related to specific topics, identify regions where data are missing, and point out inconsistencies in existing data. The general methodology used in producing evaluated compilations is described. Recently completed projects and work in progress are reported

  20. Production and decay of heavy selectrons; Produktion und Nachweis schwerer Selektronen

    Energy Technology Data Exchange (ETDEWEB)

    Csallner, S.

    2007-04-03

    We investigate the production and the decay of selectrons with masses beyond the threshold for pair production at future linear colliders with center-of-mass energies of 500 GeV and 800 GeV. For this we study the production of left and right selectrons in association with the lightest neutralino or chargino, respectively, via electron-electron, electron-positron and electron-photon scattering in the framework of the MSSM. Furthermore we analyse the production via electron-electron scattering in two extended models, the NMSSM and an E6-model with an additional U(1) gauge factor. (orig.)

  1. Advantages of axially aligned crystals used in positron production at future linear colliders

    Directory of Open Access Journals (Sweden)

    X. Artru

    2003-09-01

    Full Text Available The characteristics of the electron-photon showers initiated by 2 to 10 GeV electrons aligned along the ⟨111⟩ axis of tungsten crystals are compared with those for the amorphous tungsten. In this energy range, as known, the positron yield at the optimal target thicknesses is larger in a crystal case only by several percent. However, the amount of the energy deposition in a crystal turns out to be considerably (by 20%–50% lower than in an amorphous target providing the same positron yield, while the peak energy-deposition density is approximately of the same magnitude in both cases.

  2. SASP. Contributions to the 13. Symposium on atomic and surface physics and related topics

    Energy Technology Data Exchange (ETDEWEB)

    Scheier, P; Maerk, T [eds.

    2002-07-01

    The XIII symposium on Atomic and Surface Physics and related Topics (SASP) is devoted to cover the research of interactions between ions, electrons, photons, atoms, molecules and clusters and their interaction with surfaces. This year there was a special session dedicated to proton transfer reaction mass spectrometry covering its applications in different fields and a mini symposium on the radiation action on bio-molecules such as uracil. The contributions included in the proceeding correspond to invited lectures and poster sessions, consisting of short and extended abstracts as well as short articles. (nevyjel)

  3. EGS code system: computer programs for the Monte Carlo simulation of electromagnetic cascade showers. Version 3. [EGS, PEGS, TESTSR, in MORTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Ford, R.L.; Nelson, W.R.

    1978-06-01

    A code to simulate almost any electron--photon transport problem conceivable is described. The report begins with a lengthy historical introduction and a description of the shower generation process. Then the detailed physics of the shower processes and the methods used to simulate them are presented. Ideas of sampling theory, transport techniques, particle interactions in general, and programing details are discussed. Next, EGS calculations and various experiments and other Monte Carlo results are compared. The remainder of the report consists of user manuals for EGS, PEGS, and TESTSR codes; options, input specifications, and typical output are included. 38 figures, 12 tables. (RWR)

  4. Diamonds for beam instrumentation

    International Nuclear Information System (INIS)

    Griesmayer, Erich

    2013-01-01

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  5. Silicon PIN diode based electron-gamma coincidence detector system for Noble Gases monitoring.

    Science.gov (United States)

    Khrustalev, K; Popov, V Yu; Popov, Yu S

    2017-08-01

    We present a new second generation SiPIN based electron-photon coincidence detector system developed by Lares Ltd. for use in the Noble Gas measurement systems of the International Monitoring System and the On-site Inspection verification regimes of the Comprehensive Nuclear-Test Ban Treaty (CTBT). The SiPIN provide superior energy resolution for electrons. Our work describes the improvements made in the second generation detector cells and the potential use of such detector systems for other applications such as In-Situ Kr-85 measurements for non-proliferation purposes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Experimental Search for a Heavy Electron

    Science.gov (United States)

    Boley, C. D.; Elias, J. E.; Friedman, J. I.; Hartmann, G. C.; Kendall, H. W.; Kirk, P.N.; Sogard, M. R.; Van Speybroeck, L. P.; de Pagter, J. K.

    1967-09-01

    A search for a heavy electron of the type considered by Low and Blackmon has been made by studying the inelastic scattering of 5 BeV electrons from hydrogen. The search was made over a range of values of the mass of the heavy electron from 100 t0 1300 MeV. No evidence for such a particle was observed. Upper limits on the production cross sections were determined and employed to deducelimits on the values of the electron-photon-heavy electron coupling constant in Low and Blackmon=s theory.

  7. Quantum Information Processing and Quantum Error Correction An Engineering Approach

    CERN Document Server

    Djordjevic, Ivan

    2012-01-01

    Quantum Information Processing and Quantum Error Correction is a self-contained, tutorial-based introduction to quantum information, quantum computation, and quantum error-correction. Assuming no knowledge of quantum mechanics and written at an intuitive level suitable for the engineer, the book gives all the essential principles needed to design and implement quantum electronic and photonic circuits. Numerous examples from a wide area of application are given to show how the principles can be implemented in practice. This book is ideal for the electronics, photonics and computer engineer

  8. The CMS High-Level Trigger

    International Nuclear Information System (INIS)

    Covarelli, R.

    2009-01-01

    At the startup of the LHC, the CMS data acquisition is expected to be able to sustain an event readout rate of up to 100 kHz from the Level-1 trigger. These events will be read into a large processor farm which will run the 'High-Level Trigger'(HLT) selection algorithms and will output a rate of about 150 Hz for permanent data storage. In this report HLT performances are shown for selections based on muons, electrons, photons, jets, missing transverse energy, τ leptons and b quarks: expected efficiencies, background rates and CPU time consumption are reported as well as relaxation criteria foreseen for a LHC startup instantaneous luminosity.

  9. The CMS High-Level Trigger

    CERN Document Server

    Covarelli, Roberto

    2009-01-01

    At the startup of the LHC, the CMS data acquisition is expected to be able to sustain an event readout rate of up to 100 kHz from the Level-1 trigger. These events will be read into a large processor farm which will run the "High-Level Trigger" (HLT) selection algorithms and will output a rate of about 150 Hz for permanent data storage. In this report HLT performances are shown for selections based on muons, electrons, photons, jets, missing transverse energy, tau leptons and b quarks: expected efficiencies, background rates and CPU time consumption are reported as well as relaxation criteria foreseen for a LHC startup instantaneous luminosity.

  10. The CMS High-Level Trigger

    Science.gov (United States)

    Covarelli, R.

    2009-12-01

    At the startup of the LHC, the CMS data acquisition is expected to be able to sustain an event readout rate of up to 100 kHz from the Level-1 trigger. These events will be read into a large processor farm which will run the "High-Level Trigger" (HLT) selection algorithms and will output a rate of about 150 Hz for permanent data storage. In this report HLT performances are shown for selections based on muons, electrons, photons, jets, missing transverse energy, τ leptons and b quarks: expected efficiencies, background rates and CPU time consumption are reported as well as relaxation criteria foreseen for a LHC startup instantaneous luminosity.

  11. ITS Version 3.0: Powerful, user-friendly software for radiation modelling

    International Nuclear Information System (INIS)

    Kensek, R.P.; Halbleib, J.A.; Valdez, G.D.

    1993-01-01

    ITS (the Integrated Tiger Series) is a powerful, but user-friendly, software package permitting state-of-the-art modelling of electron and/or photon radiation effects. The programs provide Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields. The ITS system combines operational simplicity and physical accuracy in order to provide experimentalist and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems

  12. Beam dynamics simulation in the X-ray Compton source

    Energy Technology Data Exchange (ETDEWEB)

    Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A. E-mail: shcherbakov@kipt.kharkov.ua; Zelinsky, A

    2002-05-01

    At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

  13. Beam dynamics simulation in the X-ray Compton source

    International Nuclear Information System (INIS)

    Gladkikh, P.; Karnaukhov, I.; Telegin, Yu.; Shcherbakov, A.; Zelinsky, A.

    2002-01-01

    At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center

  14. Beam dynamics simulation in the X-ray Compton source

    CERN Document Server

    Gladkikh, P; Telegin, Yu P; Shcherbakov, A; Zelinsky, A

    2002-01-01

    At the National Science Center 'Kharkov Institute of Physics and Technology' the X-ray source based on Compton scattering has been developed. The computer code for simulation of electron beam dynamics with taking into account the Compton scattering effect based on Monte Carlo method is described in this report. The first results of computer simulation of beam dynamics with electron-photon interaction, parameters of electron and photon beams are presented. Calculations were carried out with the lattice of synchrotron light source SRS-800 Ukrainian Synchrotron Center.

  15. Orientation, alignment and polarisation in electron-helium collisions

    International Nuclear Information System (INIS)

    Beijers, J.P.M.

    1987-01-01

    In this thesis electron-photon coincidence experiments to study the excitation of helium by electron impact are updated. This is achieved by cross firing a well collimated and mono-energetic electron beam with a thermal helium beam and measuring the angular and/or polarisation distribution of the decay photons in coincidence with the inelastically scattered electrons. In this way target parameters are determined for the 2 1 P, 3 1 P, 3 1 D and 3 3 P states of helium. (Auth.)

  16. Electron energy deposition in a multilayered carbon--uranium--carbon configuration and in semi-infinite uranium

    International Nuclear Information System (INIS)

    Lockwood, G.J.; Miller, G.H.; Halbleib, J.A. Sr.

    1977-10-01

    Absolute measurements of electron energy deposition profiles are reported here for electrons incident on the multilayer configuration of carbon-uranium-carbon. These measurements were for normally incident source electrons at an energy of 1.0 MeV. To complement these measurements, electron energy deposition profiles were also obtained for electrons incident on semi-infinite uranium as a function of energy and angle of incidence. The results are compared with the predictions of a coupled electron/photon Monte Carlo transport model. In general, the agreement between theory and experiment is good. This work was in support of the Reactor Safety Research Equation-of-State Program

  17. Scientific conference at the Department of Biomedical Sciences, Russian Academy of Medical Sciences

    International Nuclear Information System (INIS)

    Rybakova, M.N.

    1997-01-01

    Review of reports at the scientific conference of the department of biomedical sciences of the Russian Academy of Medical Sciences, held in April, 1997, on the topic of Novel techniques in biomedical studied. Attention was paid to the creation and uses of rapid diagnosis instruments in micro devices, to the development of electron-photon, immuno enzyme and radionuclide techniques and their realization in automatic special equipment. Delay of native industry in creation of scientific-capacious highly efficient products, especially in the field of radiodiagnosis and instruments for laboratory studies was marked

  18. Project objectives and progress at the Research Laboratory of Electronics

    International Nuclear Information System (INIS)

    Allen, J.

    1983-01-01

    Molecule microscopy, semiconductor surface studies, atomic resonance and scattering, reaction dynamics at semiconductor surfaces, X-ray diffuse scattering, phase transitions in chemisorbed systems, optics and quantum electronics, photonics, optical spectroscopy of disordered materials and X-ray scattering from surfaces, infrared nonlinear optics, quantum optics and electronics, microwave and millimeter wave techniques, microwave and quantum magnetics, radio astronomy, electromagnetic wave theory and remote sensing, electronic properties of amorphous silicon dioxide, photon correlation spectroscopy and applications, submicron structures fabrication, plasma dynamics, optical propagation and communication, digital signal processing, speech communication, linguistics, cognitive information processing, custom integrated circuits, communications biophysics, and physiology, are discussed

  19. arXiv Charge reconstruction study of the DAMPE Silicon-Tungsten Tracker with ion beams

    CERN Document Server

    Qiao, Rui; Guo, Dong-Ya; Zhao, Hao; Wang, Huan-Yu; Gong, Ke; Zhang, Fei; Wu, Xin; Azzarello, Phillip; Tykhonov, Andrii; Asfandiyarov, Ruslan; Gallo, Valentina; Ambrosi, Giovanni; Mazziotta, Nicola; De Mitri, Ivan

    The DArk Matter Particle Explorer (DAMPE) is one of the four satellites within Strategic Pioneer Research Program in Space Science of the Chinese Academy of Science (CAS). DAMPE can detect electrons, photons in a wide energy range (5 GeV to 10 TeV) and ions up to iron (100GeV to 100 TeV). Silicon-Tungsten Tracker (STK) is one of the four subdetectors in DAMPE, providing photon-electron conversion, track reconstruction and charge identification for ions. Ion beam test was carried out in CERN with 60GeV/u Lead primary beams. Charge reconstruction and charge resolution of STK detectors were investigated.

  20. Out of Sight, Out of Mind—On Guy Schofield’s “Sleepers”

    Directory of Open Access Journals (Sweden)

    Jamie Allen

    2011-03-01

    Full Text Available Video. Computational “3D models” don’t actually model any thing. They are assumed imitative, but in contemporary production, these are vectorized thought- objects, prototypes of notions and design ideals. The photographic image on the other hand, as a pipeline of indexical pixels, is the apogee of our attempts to describe and represent the world outside. 65,536 levels of red, green and blue, rendered into and out of the real world of electrons, photons and “live-action.”

  1. EGS code system: computer programs for the Monte Carlo simulation of electromagnetic cascade showers. Version 3

    International Nuclear Information System (INIS)

    Ford, R.L.; Nelson, W.R.

    1978-06-01

    A code to simulate almost any electron--photon transport problem conceivable is described. The report begins with a lengthy historical introduction and a description of the shower generation process. Then the detailed physics of the shower processes and the methods used to simulate them are presented. Ideas of sampling theory, transport techniques, particle interactions in general, and programing details are discussed. Next, EGS calculations and various experiments and other Monte Carlo results are compared. The remainder of the report consists of user manuals for EGS, PEGS, and TESTSR codes; options, input specifications, and typical output are included. 38 figures, 12 tables

  2. EGS4 in `94: A decade of enhancements

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W.R. [Stanford Univ., CA (United States); Bielajew, A.F.; Rogers, D.W.O. [National Research Council of Canada, Ottawa (Canada). Institute for National Measurement Standards; Hirayama, H. [National Lab. for High Energy Physics, Ibaraki-ken (Japan)

    1994-08-18

    This paper presents an overview of the developments made to the EGS4 code over the past decade. This code is a Monte Carlo code developed to study electron-photon transport properties. It is widely used, in particular in the medical physics field, it has been updated, expanded, benchmarked, and applied to a wide array of problems. The paper covers precursors to this code, a basic snapshop of its physics and calculation methods, and an overview of how it has been expanded during the past decade.

  3. Program EPICSHOW. A computer code to allow interactive viewing of the EPIC data libraries (Version 98-1). Summary documentation

    International Nuclear Information System (INIS)

    Pronyaev, V.G.; McLaughlin, P.K.

    1999-01-01

    EPICSHOW (Electron Photon Interactive Code - Show Data) is an interactive graphics code that allows users to view and interact with neutron, photon, electron and light charged particle data. Besides on screen graphics the code provides hard copy in the form of tabulated listings and Postscript output files. The code has been implemented on UNIX, IBM-PC, Power MAC, and even Laptop computers. It should be relatively easy to use it on almost any computer. All of the data included in this system is based on the Lawrence Livermore National Laboratory Databases and the neutron and photon data is used in the TART97 Monte Carlo transport code system. (author)

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

    International Nuclear Information System (INIS)

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

    2003-01-01

    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 ∼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

  5. Parallel Beam Dynamics Simulation Tools for Future Light Source Linac Modeling

    International Nuclear Information System (INIS)

    Qiang, Ji; Pogorelov, Ilya v.; Ryne, Robert D.

    2007-01-01

    Large-scale modeling on parallel computers is playing an increasingly important role in the design of future light sources. Such modeling provides a means to accurately and efficiently explore issues such as limits to beam brightness, emittance preservation, the growth of instabilities, etc. Recently the IMPACT codes suite was enhanced to be applicable to future light source design. Simulations with IMPACT-Z were performed using up to one billion simulation particles for the main linac of a future light source to study the microbunching instability. Combined with the time domain code IMPACT-T, it is now possible to perform large-scale start-to-end linac simulations for future light sources, including the injector, main linac, chicanes, and transfer lines. In this paper we provide an overview of the IMPACT code suite, its key capabilities, and recent enhancements pertinent to accelerator modeling for future linac-based light sources

  6. 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. Copyright © 2016. Published by Elsevier Ltd.

  7. Positron Factory project

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Sohei; Sunaga, Hiromi; Kaneko, Hirohisa; Kawasuso, Atsuo; Masuno, Shin-ichi; Takizawa, Haruki; Yotsumoto, Keiichi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    We have started drafting a construction program for the Positron Factory, in which linac-based intense monoenergetic positron beams are planned to be applied for materials science, biotechnology and basic physics and chemistry. A technical survey study confirmed the feasibility of manufacturing a dedicated electron linac of 100 kW class with a beam energy of 100 MeV, which will produce a world-highest monoenergetic positron beam of more than 10{sup 10}/sec in intensity. A self-driven rotating converter (electrons to positrons and photons) suitable for the high power electron beam was devised and successfully tested. The practicability of simultaneous extraction of multi-channel monoenergetic positron beams with multiple moderator assemblies, which had been originated on the basis of a Monte Carlo simulation, was demonstrated by an experiment using an electron linac. An efficient moderator structure, which is composed of honeycomb-like assembled moderator foils and reflectors, is also proposed. (author)

  8. The CEBAF [Continuous Electron Beam Accelerator Facility] superconducting accelerator: An overview

    International Nuclear Information System (INIS)

    Leemann, C.W.

    1986-01-01

    The CEBAF accelerator is a CW linac based on rf superconductivity and making use of multiple recirculation. Its major components are a 50 MeV injector, two linac segments of 0.5 GeV energy gain each, and recirculator arcs connecting the two linac segments. Each linac segment consists of 25 cryomodules, separated by warm sections with quadrupoles, steering magnets, and beam diagnostics. Each cryomodule contains 8, 1500 MHz, 5-cell, Cornell type cavities with waveguide couplers for fundamental power and HOM damping, each cavity being powered by its own klystron. Recirculator arcs are vertically stacked, large radius, strong focusing beam lines that minimize synchrotron radiation effects. A high quality (ΔE/E ∼ 10 -4 , ε ∼ 10 -9 m) beam of 200μA, 100% duty factor, with 0.5 GeV ≤ E ≤ 4.0 GeV will be generated

  9. TH-C-BRC-01: An Overview of Emerging Technologies in SRS/SBRT Delivery

    International Nuclear Information System (INIS)

    Ma, L.

    2016-01-01

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  10. A high-gradient high-duty-factor Rf photo-cathode electron gun

    International Nuclear Information System (INIS)

    Rimmer, Robert A.; Hartman, Neal; Lidia, Steven M.; Wang, Shaoheng

    2002-01-01

    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

  11. A high-gradient high-duty-factor RF photo-cathode electron gun

    International Nuclear Information System (INIS)

    Rimmer, Robert; Hartman, N.; Lidia, S.; Wang, S.H.

    2002-01-01

    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

  12. Design of RF chopper system for improving beam quality in FEL injector with thermionic gun

    International Nuclear Information System (INIS)

    Chen, Q.; Qin, B.; Tan, P.; Hu, T.; Pei, Y.; Zhang, F.

    2014-01-01

    For a linac-based Free Electron Laser (FEL), good beam quality largely contributes to the success of the final radiation. An imperfection confronted with the HUST THz-FEL facility is the long beam tail that emerges in the electron gun and exists through the whole beam line. This paper proposes to deploy a chopper system after the electron gun to truncate the beam tails before they enter into the linac. Physical dimensions of the chopper cavity are discussed in detail and we have developed and derived new analytical expressions applying to all frequencies for the optimal design. Also, technical issues of the cavity are considered. Beam dynamic simulation is performed to examine the truncation effect and the results show that more than 78% of the beam tail can be removed effectively, while preserving the emittance and energy spread in acceptable level

  13. Important aspects of linac beams for food irradiation

    International Nuclear Information System (INIS)

    McKeown, J.; Jones, R.T.

    1987-01-01

    Linac based irradiators will require careful design before they can be routinely adopted for the radiation processing of food. The transverse emittance and energy spread from simple injectors provide a significant challenge to the design of a beam delivery system which must handle high power especially in photon mode. Any nonuniform current distribution at the plane of the product is further complicated by large dose variations near the air/product interface, even with simple geometries. The paper describes the use of methods developed at AECL to control and monitor linac behaviour as well as electron interactions at the product surface. It also reports on activation cross-section measurements and particularly on neutron yields from composite targets, designed to monitor the energy of accelerators used in food applications. (orig.)

  14. 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)

  15. TH-C-BRC-00: Emerging Technologies in SRS/SBRT Delivery

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  16. TH-C-BRC-02: A Review of Emerging Technologies in Robotic SRS/SBRT Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L. [Stanford University Cancer Center (United States)

    2016-06-15

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  17. TH-C-BRC-01: An Overview of Emerging Technologies in SRS/SBRT Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L. [UCSF Comprehensive Cancer Center, San Francisco, CA (United States)

    2016-06-15

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  18. Harmonic Content of the BESSY FEL Radiation

    CERN Document Server

    Meseck, Atoosa

    2005-01-01

    BESSY proposes a linac-based cascaded High-Gain Harmonic-Generation (HGHG) free electron laser (FEL) multi-user facility. The BESSY soft X-ray FEL will consist of three undulator lines. The associated tunable lasers will cover the spectral range of 230nm to 460nm. Two to four HGHG stages reduce the seed wavelength to the desired radiation range of 1.24nm < λ < 51nm. The harmonic content of the high-intensity radiator output can be used to reduce the number of necessary HGHG stages. Moreover the higher harmonic content of the final output extends the offered spectral range and thus is of high interest for the user community. In this paper, the higher harmonic content of the final output as well as of the output of several radiators are investigated. The main parameters such as output power, pulse duration and bandwidth as well as their suitability for seeding are discussed.

  19. Present status of positron factory project

    International Nuclear Information System (INIS)

    Okada, S.; Sunaga, H.; Kaneko, H.; Tachibana, H.; Yotsumoto, K.; Okamoto, J.

    1992-01-01

    The Japan Atomic Energy Research Institute, JAERI, has been promoting design studies for the 'Positron Factory', in which linac-based intense monoenergetic positron beams are planned to be applied to advanced materials characterization and new fields of basic research. A tentative goal of the beam intensity is 10 10 s -1 , which is assumed to be realized with an electron linac of 100 kW class with a beam energy around 100 to 150 MeV. We performed a technical survey on the dedicated linac. It confirmed technical feasibility of manufacturing the state-of-the-art machine. We have been carrying out a design study of the target. A new concept of the target design is proposed, which is expected to supply intense slow positron beams simultaneously for multiple beam channels, on the basis of Monte Carlo simulations. (author)

  20. TH-C-BRC-00: Emerging Technologies in SRS/SBRT Delivery

    International Nuclear Information System (INIS)

    2016-01-01

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  1. Status report of the KAERI/NDEL. P1

    International Nuclear Information System (INIS)

    Chang, Jonghwa

    2001-01-01

    KAERI/NDEL has successfully finished a 4 year national nuclear Research and Development project, Establishment of Nuclear Data System, and started a new 4 year project, Evaluation of Nuclear Data for Nuclear Research and development Projects. KAERI/NDEL is providing nuclear data on-line service targeting non-nuclear data experts. Three new facilities have been added for nuclear data measurement capability of Korea, namely, E-Linac based TOF; Tandem VDG based n-source; and Cyclotron based Vacuum chamber. Main directions of nuclear data development on next 4 years are the Fission Products data for Transmutation, the data for Thorium cycle, the Photon-production data for in-core detector, and the Intermediate energy data for ADS

  2. TH-C-BRC-02: A Review of Emerging Technologies in Robotic SRS/SBRT Delivery

    International Nuclear Information System (INIS)

    Wang, L.

    2016-01-01

    The delivery techniques for SRS/SBRT have been under rapid developments in recent years, which pose new challenges to medical physicists ranging from planning and quality assurance to imaging and motion management. This educational course will provide a general overview of the latest delivery techniques in SRS/SBRT, and discuss the clinical processes to address the challenges of each technique with special emphasis on dedicated gamma-ray based device, robotic x-band linac-based system and conventional C-arm s-band linac-based SRS systems. (1). Gamma-ray based SRS/SRT: This is the gold standard of intracranial SRS. With the advent of precision imaging guidance and frameless patient positioning capabilities, novel stereoscopic CBCT and automatic dose adaption solution are introduced to the Gamma-ray based SRS for the first time. The first North American system has been approved by the US regulatory for patient treatments in the spring of 2016. (2). Robotic SRS/SBRT system: A number of technological milestones have been developed in the past few years, including variable aperture collimator, sequential optimization technique, and the time reduction technique. Recently, a new robotic model allows the option of a multi-leaf collimator. These technological advances have reduced the treatment time and improved dose conformity significantly and could potentially expand the application of radiosurgery for the treatment of targets not previously suitable for robotic SRS/SBRT or fractionated stereotactic radiotherapy. These technological advances have created new demanding mandates on hardware and patient quality assurance (QA) tasks, as well as the need for updating/educating the physicists in the community on these requirements. (3). Conventional Linac based treatments: Modulated arc therapy (MAT) has gained wide popularities in Linac-based treatments in recent years due to its high delivery efficiency and excellent dose conformities. Recently, MAT has been introduced to

  3. 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...

  4. 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.

  5. 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.

  6. rf conditioning and breakdown analysis of a traveling wave linac with collinear load cells

    Science.gov (United States)

    Chen, Qushan; Hu, Tongning; Qin, Bin; Xiong, Yongqian; Fan, Kuanjun; Pei, Yuanji

    2018-04-01

    Huazhong University of Science and Technology (HUST) has built a compact linac-based terahertz free electron laser (THz-FEL) prototype. In order to achieve compact structure, the linac uses collinear load cells instead of conventional output coupler to absorb remanent power at the end of linac. The new designed structure is confronted with rf breakdown problem after a long time conditioning process, so we tried to figure out the breakdown site in the linac. Without transmitted signal, we propose two methods to analyze the breakdown site mainly based on the forward and the reflected power signals. One method focuses on the time relationship of the two signals while the other focuses on the amplitude. Both the two methods indicate the breakdown events happened at the end of the linac and more likely in the first or the second load cell.

  7. rf conditioning and breakdown analysis of a traveling wave linac with collinear load cells

    Directory of Open Access Journals (Sweden)

    Qushan Chen

    2018-04-01

    Full Text Available Huazhong University of Science and Technology (HUST has built a compact linac-based terahertz free electron laser (THz-FEL prototype. In order to achieve compact structure, the linac uses collinear load cells instead of conventional output coupler to absorb remanent power at the end of linac. The new designed structure is confronted with rf breakdown problem after a long time conditioning process, so we tried to figure out the breakdown site in the linac. Without transmitted signal, we propose two methods to analyze the breakdown site mainly based on the forward and the reflected power signals. One method focuses on the time relationship of the two signals while the other focuses on the amplitude. Both the two methods indicate the breakdown events happened at the end of the linac and more likely in the first or the second load cell.

  8. High time resolution beam-based measurement of the rf-to-laser jitter in a photocathode rf gun

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2014-03-01

    Full Text Available Characterizing the rf-to-laser jitter in the photocathode rf gun and its possible origins is important for improving the synchronization and beam quality of the linac based on the photocathode rf gun. A new method based on the rf compression effect in the photocathode rf gun is proposed to measure the rf-to-laser jitter in the gun. By taking advantage of the correlation between the rf compression and the laser injection phase, the error caused by the jitter of the accelerating field in the gun is minimized and thus 10 fs time resolution is expected. Experimental demonstration at the Tsinghua Thomson scattering x-ray source with a time resolution better than 35 fs is reported in this paper. The experimental results are successfully used to obtain information on the possible cause of the jitter and the accompanying drifts.

  9. Virtual simulation. First clinical results in patients with prostate cancer

    International Nuclear Information System (INIS)

    Buchali, A.; Dinges, S.; Koswig, S.; Rosenthal, P.; Salk, S.; Harder, C.; Schlenger, L.; Budach, V.

    1998-01-01

    Investigation of options of virtual simulation in patients with localized prostate cancer. Twenty-four patients suffering from prostate cancer were virtual simulated. The clinical target volume was contoured and the planning target volume was defined after CT scan. The isocenter of the planning target volume was determined and marked at patient's skin. The precision of patients marking was controlled with conventional simulation after physical radiation treatment planning. Mean differences of the patient's mark revealed between the 2 simulations in all room axes around 1 mm. The organs at risk were visualized in the digital reconstructed radiographs. The precise patient's mark of the isocentre by virtual simulation allows to skip the conventional simulation. The visualisation of organs at risk leeds to an unnecessarity of an application of contrast medium and to a further relieve of the patient. The personal requirement is not higher in virtual simulation than in conventional CT based radiation treatment planning. (orig./MG) [de

  10. Assessment of a Philips' Pendo Diagnost and Traumob C system for skull radiography

    International Nuclear Information System (INIS)

    1983-03-01

    The design of the system assessed introduces a number of innovations for positioning for skull radiography. These include: facilities for rotation of the table about the isocentre of the X-ray beam, digital indication of angular and linear movement, stationary cross light positioning aids for lateral and frontal projections, and vertical movement of the table top. The report commends the features of the design which allow precise, reproducible positioning with minimal patient disturbance for skull and casualty radiography. These features include the clever light aids mentioned above, the ability to view the patient through the cassette holders, well positioned controls for the effectively braked movements, and a variable-height, floating-top and wheeled patient-table. (author)

  11. Design of a "Riesenrad" Ion Gantry for Hadrontherapy

    CERN Document Server

    Reimoser, S

    2000-01-01

    The benefit of hadrontherapy can be maximized by offering the possibility to deliver the particle beam from any direction in space towards the patient with the help of a medical gantry. For carbon ions, their increased (magnetic) beam rigidity yields considerable structural difficulties and has so far prevented a practical realization of an ion gantry. The concept of a 'Riesenrad' ion gantry promises to provide an effective and efficient solution. The basic idea is to deflect the ion beam with a single 90° dipole, which rotates around the incoming beam axis, and direct it towards the eccentrically positioned patient cabin. Inside the cabin similar conditions as exist in a classical isocentric treatment room prevail. The practical design of such a Riesenrad gantry, its structural principles and its function are presented. The underlying beam optics and its integration into the mechanical structure are explained. Aspects of safety, and flexibility are discussed.

  12. Characterization of an add-on multileaf collimator for electron beam therapy

    International Nuclear Information System (INIS)

    Gauer, T; Sokoll, J; Cremers, F; Schmidt, R; Harmansa, R; Luzzara, M

    2008-01-01

    An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the isocentre through interchangeable holders. The mechanical implementation of this feature results in a maximum field displacement of less than 0.6 mm at 90 0 and 270 0 gantry angles. Compared to a 10 x 10 cm applicator at 6-14 MeV, the beam penumbra of the eMLC at a 16 cm collimator-to-isocentre distance is 0.8-0.4 cm greater and the depth-dose curves show a larger build-up effect. Due to the loss in energy dependence of the therapeutic range and the much lower dose output at small beam sizes, a minimum beam size of 3 x 3 cm is necessary to avoid suboptimal dose delivery. Dose output and beam symmetry are not affected by collimator scatter when the central axis is blocked. As a consequence of the broader beam penumbra, uniform dose distributions were measured in the junction region of adjacent beams at perpendicular and oblique beam incidence. However, adjacent beams with a high difference in a beam energy of 6 to 14 MeV generate cold and hot spots of approximately 15% in the abutting region. In order to

  13. Biophysical sciences

    International Nuclear Information System (INIS)

    1988-01-01

    The neutron therapy system consists of an isocentric gantry capable of ± 185 degrees rotation. Field sizes of between 5 x 5 cm 2 and 30 x 30 cm 2 are defined by a rotatable continuously variable collimator. Neutrons are produced by the p(66 MeV)/Be(40 MeV) reaction. Basic neutron beam data were initially measured in order to provide sufficient information for radiobiological experiments to be undertaken. Some of these experiments indicated a differential in the biological effectiveness of the beam at the surface and at depth in a phantom. In order to reduce this differential at 2.5 cm thick polyethylene beam-hardening filter has been mounted in the treatment head. In addition beam-flattening filters are now also being used to flatten the beam profiles at depth in phantom. Measurements of the characteristics of the beam with the new configuration are still in progress. 12 figs., 6 refs

  14. Semi-empirical equivalent field method for dose determination in midline block fields for cobalt - 60 beam

    International Nuclear Information System (INIS)

    Tagoe, S.N.A.; Nani, E.K.; Yarney, J.; Edusa, C.; Quayson-Sackey, K.; Nyamadi, K.M.; Sasu, E.

    2012-01-01

    For teletherapy treatment time calculations, midline block fields are resolved into two fields, but neglecting scattering from other fields, the effective equivalent square field size of the midline block is assumed to the resultant field. Such approach is underestimation, and may be detrimental in achieving the recommended uncertainty of ± 5 % for patient's radiation dose delivery. By comparison, the deviations of effective equivalent square field sizes by calculations and experiments were within 13.2 % for cobalt 60 beams of GWGP80 cobalt 60 teletherapy. Therefore, a modified method incorporating the scatter contributions was adopted to estimate the effective equivalent square field size for midline block field. The measured outputs of radiation beams with the block were compared with outputs of square fields without the blocks (only the block tray) at depths of 5 and 10 cm for the teletherapy machine employing isocentric technique, and the accuracy was within ± 3 % for the cobalt 60 beams. (au)

  15. A six-bank multi-leaf system for high precision shaping of large fields

    International Nuclear Information System (INIS)

    Topolnjak, R; Heide, U A van der; Raaymakers, B W; Kotte, A N T J; Welleweerd, J; Lagendijk, J J W

    2004-01-01

    In this study, we present the design for an alternative MLC system that allows high precision shaping of large fields. The MLC system consists of three layers of two opposing leaf banks. The layers are rotated 60 deg. relative to each other. The leaves in each bank have a standard width of 1 cm projected at the isocentre. Because of the symmetry of the collimator set-up it is expected that collimator rotation will not be required, thus simplifying the construction considerably. A 3D ray tracing computer program was developed in order to simulate the fluence profile for a given collimator and used to optimize the design and investigate its performance. The simulations show that a six-bank collimator will afford field shaping of fields of about 40 cm diameter with a precision comparable to that of existing mini MLCs with a leaf width of 4 mm

  16. Safety Improvement in Radiotherapy Treatment Plan. Planning vs Redundant Check vs in vivo Dosimetry

    International Nuclear Information System (INIS)

    Torres Diaz, J.; Ascencion Ybarra, Y.; La Fuentes Rosales, L. de; Lara Mas, E.; Larrinaga Cortinas, E.

    2013-01-01

    In Cuba it is mandatory to have an independent monitor units check before any radiotherapy treatment is started. The main objective of this paper is to enhance the safety of the radiotherapy planning by developing and testing a practical tool to double check the monitor units calculation for external beam high energy photon therapy. A software for monitor units (MUs) verification was designed and coded. It considers the common in clinical practice isocentric set-ups. The in vivo dosimetry measurements were done with a silicon diode system for 6 MV photon beams to support the validation of the software. The results show a discrepancy within 5% between the 3 methods which is in accordance with international recommendations. (Author)

  17. Preliminary design of a dedicated proton therapy linac

    International Nuclear Information System (INIS)

    Hamm, R.W.; Crandall, K.R.; Potter, J.M.

    1991-01-01

    The preliminary design has been completed for a low current, compact proton linac dedicated to cancer therapy. A 3 GHz side-coupled structure accelerates the beam from a 70 MeV drift tube linac using commercially available S-band rf power systems and accelerating cavities. This significantly reduces the linac cost and allows incremental energies up to 250 MeV. The short beam pulse width and high repetition rate make the linac similar to the high energy electron linacs now used for cancer therapy, yet produce a proton flux sufficient for treatment of large tumors. The high pulse repetition rate permits raster scanning, and the small output beam size and emittance result in a compact isocentric gantry design. Such a linac will reduce the facility and operating costs for a dedicated cancer therapy system

  18. Evaluation of the uncertainties in the TLD radiosurgery postal dose system

    Science.gov (United States)

    Campos, L. T.; Leite, S. P.; de Almeida, C. E. V.; Magalhães, L. A. G.

    2018-03-01

    Stereotactic radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. To guarantee a high quality standard, a comprehensive Quality Assurance programme is extremely important to ensure that the measured dose is consistent with the tolerance considered to improve treatment quality. The Radiological Science Laboratory operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy in known geometry and the dosimetric conditions of the TPS. The programme works in such a way those thermoluminescence dosimeters, consisting of LiF chips, are sent to the centre where they are to be irradiated to a certain dose. The TLD are then returned, where they are evaluated and the absorbed dose is obtained from TLDs readings. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data.

  19. Stereotactic radiosurgery

    International Nuclear Information System (INIS)

    Souhami, L.; Podgorsak, E.B.

    1990-01-01

    Radiosurgery is an irradiation technique which over the last few years became frequently utilized. Because of the sophisticated and expensive equipments originally required, its use was restricted initially to a few and specialized centers in the world. The introduction of new techniques based on isocentric linear accelerators made now this therapy available to the major radiotherapy centers. Some of the essential requirements for radiosurgery include an accurate determination of the target volume, 3-dimensional dose calculation, accurate dose delivery to the target volume and a sharp dose fall-off outside the target volume. In this paper, we discuss the principles, the indications, some of the techniques, and the initial therapeutics results with radiosurgery. (author) [pt

  20. Dual purpose QA tool developed for teletherapy unit and CT scan in SNDH

    International Nuclear Information System (INIS)

    Shilvant, D.V.; Tamane, C.J.; Pangam, S.B.; Raees, M.D.; Aynoor, S.K.; Pol, P.S.; Verghese, Aju; Ghorpade, C.J.

    2007-01-01

    To make a simple device used in Teletherapy unit and CT scan for depth data measurement. The accurate depth data is essential and very important factor for precise treatment in SAD isocentric setup calculation. In CT scan based treatment planning, the calculation obtained is from the depth given by the CT scan. The success of treatment depends on the same parameters in treatment unit matched with diagnostic CT scan data. To check the depth parameters in both CT scan and Teletherapy unit we have developed a single QA tool in our hospital. As this tool is precise, handy and easily accessible the results obtained from it assures the quality of Teletherapy unit as well as CT scan depth data. This small device resulted data helps a lot in calculations of complicated SAD setup in Telecobalt and also useful in recent new treatment modalities such as IMRT, micro MLC, etc

  1. The Italian project for a hadrontherapy centre

    Energy Technology Data Exchange (ETDEWEB)

    Amaldi, U. [European Organization for Nuclear Research, Geneva (Switzerland)]|[Universita di Milano, Como Seat, Via Lucini 3, 22100 Como (Italy); Arduini, G. [ASP, Villa Gualino, Via Settimio Severo 65, 10133 Torino (Italy); Badano, L. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Cambria, R. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Campi, D. [European Organization for Nuclear Research, Geneva (Switzerland); Gerardi, F. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Gramatica, F. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Leone, R. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Manfredi, G. [Consiglio Nazionale delle Ricerche, ITBA, Via Ampere 56, 20131 Milano (Italy); Nonis, M. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Pullia, M. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Rossi, S. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy); Sangaletti, L. [Fondazione Italiana Ricerca sul Cancro, Via F. Corridoni 7, 20122 Milano (Italy); Silari, M. [Consiglio Nazionale delle Ricerche, ITBA, Via Ampere 56, 20131 Milano (Italy); Tosi, G. [Fondazione per Adroterapia Oncologica, Via Puccini 11, 28100 Novara (Italy)]|[Istituto Europeo di Oncologia, Via Ripamonti 435, 22100 Milano (Italy)

    1995-06-01

    A feasibility study has just been completed for a hospital-based hadrontherapy facility to be built in Italy. This facility aims at the treatment of 1000 patients/year in 5 treatment rooms served by a H{sup -}/light ion synchrotron producing proton beams with energies ranging from 60 to 250 MeV. Generation of neutron beams for boron neutron capture therapy and production of positron emitting radionuclides for PET diagnostics is also foreseen. After an account of the rationale for the use of hadron beams in radiation therapy, a brief overview is given of both the technical components and the facility layout. Two of the treatment rooms will be equipped with a rotating isocentric irradiation unit. The design foresees the possibility of implementing, as a future development, acceleration of fully stripped light ions up to {sup 16}O to energies in the 120-400 MeV/u range. (orig.).

  2. Characterization of an add-on multileaf collimator for electron beam therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gauer, T; Sokoll, J; Cremers, F; Schmidt, R [Department of Radiotherapy and Radio-Oncology, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Harmansa, R [3D Line, Schwarzenbruck (Germany); Luzzara, M [3D Line, Milan (Italy)], E-mail: t.gauer@uke.uni-hamburg.de

    2008-02-21

    An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the isocentre through interchangeable holders. The mechanical implementation of this feature results in a maximum field displacement of less than 0.6 mm at 90{sup 0} and 270{sup 0} gantry angles. Compared to a 10 x 10 cm applicator at 6-14 MeV, the beam penumbra of the eMLC at a 16 cm collimator-to-isocentre distance is 0.8-0.4 cm greater and the depth-dose curves show a larger build-up effect. Due to the loss in energy dependence of the therapeutic range and the much lower dose output at small beam sizes, a minimum beam size of 3 x 3 cm is necessary to avoid suboptimal dose delivery. Dose output and beam symmetry are not affected by collimator scatter when the central axis is blocked. As a consequence of the broader beam penumbra, uniform dose distributions were measured in the junction region of adjacent beams at perpendicular and oblique beam incidence. However, adjacent beams with a high difference in a beam energy of 6 to 14 MeV generate cold and hot spots of approximately 15% in the abutting region. In

  3. Total body irradiation with a reconditioned cobalt teletherapy unit.

    Science.gov (United States)

    Evans, Michael D C; Larouche, Renée-Xavière; Olivares, Marina; Léger, Pierre; Larkin, Joe; Freeman, Carolyn R; Podgorsak, Ervin B

    2006-01-01

    While the current trend in radiotherapy is to replace cobalt teletherapy units with more versatile and technologically advanced linear accelerators, there remain some useful applications for older cobalt units. The expansion of our radiotherapy department involved the decommissioning of an isocentric cobalt teletherapy unit and the replacement of a column-mounted 4-MV LINAC that has been used for total body irradiation (TBI). To continue offering TBI treatments, we converted the decommissioned cobalt unit into a dedicated fixed-field total body irradiator and installed it in an existing medium-energy LINAC bunker. This article describes the logistical and dosimetric aspects of bringing a reconditioned cobalt teletherapy unit into clinical service as a total body irradiator.

  4. Designing for cancer care

    International Nuclear Information System (INIS)

    Jefferson, John; Mason, Andrew; Hill, Fred; Gosnell, Jeffrey; Westwood, Jacquie; Jones, Mike; Field, Anthony; Dawson, Susan.

    1993-01-01

    A description of the recently-built Mid-Kent Oncology Centre is given. There are brief comments from the client, architect, structural engineer, science engineer and users. A brief appraisal and cost comment are included. The working details and plan of the linear accelerator enclosure, which houses the high-and medium-energy linear accelerators are given. The mass and geometry provide protection from radiation; the walls and roof are made of thick reinforced concrete and have an additional primary radiation protective collar surrounding the isocentre of the linear accelerator. Neutrons given off by the accelerator are controlled by a neutron attenuating wax-like substance and a coating on the back of the walls and ceiling. Access is controlled and staff monitor the treatment from a control room. (UK)

  5. Quality control of a virtual simulation installation. SFPM report nr 25, August 2009

    International Nuclear Information System (INIS)

    Foulquier, Jean-Noel; Allieres, Norbert; Batalla, Alain; Beaumont, Stephane; Di Bartolo, Cristelle; Khodri, Mustapha; Tauziede, Jean-Marc; Dedieu, Veronique; Bramoule, Celine; Caselles, Olivier; Lacaze, Brigitte; Mazurier, Jocelyne

    2009-08-01

    This report is a notably comprehensive guide for the different controls which can be performed on devices present in a Virtual Simulation installation. After a brief historical recall, the authors present the definition and organisation of a virtual simulation, the different components of a virtual simulation installation, and the different steps of virtual simulation process. Then, they address the quality control of the scanner-simulator (linearity and periodicity of controls, patient table or support, tolerance levels and periodicity of controls of this support). They address tracking systems (quality control of laser systems), the quality control of virtual simulation tools (iso-centre contouring and positioning, ballistic tools, tolerance levels, control periodicity), the quality control of data transfer or objects (elements to be analysed during an image transfer, tolerance levels and control periodicity), the imager quality control, and tests phantoms (the physical and digital phantoms)

  6. The proton therapy system for MGH's NPTC: equipment description and progress report

    International Nuclear Information System (INIS)

    Jongen, Y.; Beeckman, W.; Cohilis, P.

    1996-01-01

    At the beginning of 1994, the Massachusetts General Hospital (MGH) of the Harvard Medical School in Boston (MA, USA) a pioneer in proton therapy since 1959, selected a team led by Ion Beam Applications SA (IBA) to supply the proton therapy equipment of its new Northeast Proton Therapy Centre (NPTC),. The IBA integrated system includes a compact 235 MeV isochronous cyclotron, a short energy selection transforming the fixed energy beam extracted form the cyclotron into a variable energy beam, one or more isocentric gantries fitted with a nozzle, a system consisting of one or more horizontal beam lines, a global control system including an accelerator control unit and several independent but networked therapy control stations, a global safety management system, and a robotic patient positioning system. The present paper presents the equipment being built for the NPTC. (author)

  7. Two new DOSXYZnrc sources for 4D Monte Carlo simulations of continuously variable beam configurations, with applications to RapidArc, VMAT, TomoTherapy and CyberKnife

    International Nuclear Information System (INIS)

    Lobo, Julio; Popescu, I Antoniu

    2010-01-01

    We present two new Monte Carlo sources for the DOSXYZnrc code, which can be used to compute dose distributions due to continuously variable beam configurations. These sources support a continuously rotating gantry and collimator, dynamic multileaf collimator (MLC) motion, variable monitor unit (MU) rate, couch rotation and translation in any direction, arbitrary isocentre motion with respect to the patient and variable source-to-axis distance (SAD). These features make them applicable to Monte Carlo simulations for RapidArc(TM), Elekta VMAT, TomoTherapy(TM) and CyberKnife(TM). Unique to these sources is the synchronization between the motion in the DOSXYZnrc geometry and the motion within the linac head, represented by a shared library (either a BEAMnrc accelerator with dynamic component modules, or an external library). The simulations are achieved in single runs, with no intermediate phase space files.

  8. Tumour regrowth after irradiation. An experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, H; Matsuzawa, T [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer

    1979-03-01

    Structural changes in irradiated tumours and their regrowth were studied in a rat hepatoma, AH109A, using histological and transparent-chamber techniques. The development of the tumour was examined by means of vascular morphometry as observed in the chamber. Schematically, the tumour tissue was divided into four isocentric layers according to vascular morphology and measurements of vessel volume, surface area, and length per mm/sup 3/ of tissue. The vascularity was greatest in the outermost region, decreased towards the inner parts and reached an absence of vascularity at the central necrosis. The tumours were gamma- or X-irradiated with various doses. The inside hypoxic region was destroyed completely after 300 rad, and regrowths started exclusively from the outermost area of the tumour where enhancement of the effect of radiation by oxygen was thought to be greatest. Possible mechanisms of tumour regrowth are discussed.

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

    International Nuclear Information System (INIS)

    Dieterich, S; Schlesinger, D; Geneser, S

    2014-01-01

    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. Is it sufficient to repeat LINEAR accelerator stereotactic radiosurgery in choroidal melanoma?

    Science.gov (United States)

    Furdova, A; Horkovicova, K; Justusova, P; Sramka, M

    One day session LINAC based stereotactic radiosurgery (SRS) at LINAC accelerator is a method of "conservative" attitude to treat the intraocular malignant uveal melanoma. We used model Clinac 600 C/D Varian (system Aria, planning system Corvus version 6.2 verification IMRT OmniPro) with 6 MeV X by rigid immobilization of the eye to the Leibinger frame. The stereotactic treatment planning after fusion of CT and MRI was optimized according to the critical structures (lens, optic nerve, also lens and optic nerve at the contralateral side, chiasm). The first plan was compared and the best plan was applied for therapy at C LINAC accelerator. The planned therapeutic dose was 35.0 Gy by 99 % of DVH (dose volume histogram). In our clinical study in the group of 125 patients with posterior uveal melanoma treated with SRS, in 2 patients (1.6 %) was repeated SRS indicated. Patient age of the whole group ranged from 25 to 81 years with a median of 54 TD was 35.0 Gy. In 2 patients after 5 year interval after stereotactic radiosurgery for uveal melanoma stage T1, the tumor volume increased to 50 % of the primary tumor volume and repeated SRS was necessary. To find out the changes in melanoma characteristics after SRS in long term interval after irradiation is necessary to follow up the patient by an ophthalmologist regularly. One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T1 to T3 stage posterior uveal melanoma and to preserve the eye globe. In some cases it is possible to repeat the SRS after more than 5 year interval (Fig. 8, Ref. 23).

  11. Comparison of dose-volume histograms for Tomo therapy, linear accelerator-based 3D conformal radiation therapy, and intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Choi, Seong-Kwan; Chung, Woon-Kwan; Lee, Jong-Woong

    2011-01-01

    Highlights: → Evaluation of DVH from 3D CRT, IMRT and Tomo therapy was conducted for tumor therapy. → The doses of GTV and CTV were compared using DVHs from 3D CRT, IMRT and Tomo therapy. → The GTV was higher when Tomo therapy was used, while the doses of critical organ were low. → They said that Tomo therapy satisfied the goal of radiation therapy more than the others. - Abstract: Evaluation of dose-volume histograms from three-dimensional conformal radiation therapy (3D CRT), intensity-modulated radiation therapy (IMRT), and Tomo therapy was conducted. These three modalities are among the diverse treatment systems available for tumor therapy. Three patients who received tumor therapy for a malignant oligodendroglioma in the cranium, nasopharyngeal carcinoma in the cervical neck, and prostate cancer in the pelvis were selected as study subjects. Therapy plans were made for the three patients before dose-volume histograms were obtained. The doses of the gross tumor volume (GTV) and the clinical target volume (CTV) were compared using the dose-volume histograms obtained from the LINAC-based 3D CRT, IMRT planning station (Varian Eclipse-Varian, version 8.1), and Tomo therapy planning station. In addition, the doses of critical organs in the cranium, cervix, and pelvis that should be protected were compared. The GTV was higher when Tomo therapy was used compared to 3D CRT and the LINAC-based IMRT, while the doses of critical organ tissues that required protection were low. These results demonstrated that Tomo therapy satisfied the ultimate goal of radiation therapy more than the other therapies.

  12. RAPIDARC (RA) in the uterine cervical cancer; dosimetric gain vs 3D-Crt

    International Nuclear Information System (INIS)

    Ramirez, J.; Garcia, B.; Quispe, K.; Gonzales, A.; Marquina, J.

    2014-08-01

    This work aims to quantitatively assess RAPIDARC (RA) treatments versus three dimensional-Conformal Radiation Therapy with field to field technique (3D-Crt-Fin F). 11 patients with cervical cancer treated at our institution radically or adjuvant clinical stages I-III B were evaluated. The prescribed dose was 50 Gy (2 Gy / Fr). The RA plans consisted of two isocentric complete arcs and conformational plans of 4 isocentric fields (previous, subsequent, right side and left side) with 3D-Crt-Fin F technique; both cases carried out ??in the Eclipse version 10 planner with calculation algorithm analytical anisotropic algorithm (AAA) and volumetric optimization software (for VMAT plans). Homogeneity indices (Hi), conformity indices (CI) Sigma indices (S-Index), monitor units (MU) and the time required for each treatment were compared. The mean age was 52 years (32-65) of the 11 patients 9 were clinical stages I-II B. The Hi varied from 0.052 for RA to 0.163 for 3D-Crt-Fin F (p = 0.009), and the CI between 1.005 and 1.35 (p = 0.26), the S-index from 1.2 to 3.7 (p = 0.001) and the H-index of 1.08 to 1.15 (p = 0.24). All dose limits in risk organs were met with a significant difference in the RA plans versus 3D-Crt-Fin F. In patients with cervical cancer the treatment plans quality with the indices aforementioned seems to be better with the RA technique, being observed a significant reduction of radiation to surrounding organs. (author)

  13. Robotic path-finding in inverse treatment planning for stereotactic radiosurgery with continuous dose delivery

    Energy Technology Data Exchange (ETDEWEB)

    Vandewouw, Marlee M., E-mail: marleev@mie.utoronto.ca; Aleman, Dionne M. [Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario M5S 3G8 (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario M5G 2M9 (Canada)

    2016-08-15

    Purpose: Continuous dose delivery in radiation therapy treatments has been shown to decrease total treatment time while improving the dose conformity and distribution homogeneity over the conventional step-and-shoot approach. The authors develop an inverse treatment planning method for Gamma Knife® Perfexion™ that continuously delivers dose along a path in the target. Methods: The authors’ method is comprised of two steps: find a path within the target, then solve a mixed integer optimization model to find the optimal collimator configurations and durations along the selected path. Robotic path-finding techniques, specifically, simultaneous localization and mapping (SLAM) using an extended Kalman filter, are used to obtain a path that travels sufficiently close to selected isocentre locations. SLAM is novelly extended to explore a 3D, discrete environment, which is the target discretized into voxels. Further novel extensions are incorporated into the steering mechanism to account for target geometry. Results: The SLAM method was tested on seven clinical cases and compared to clinical, Hamiltonian path continuous delivery, and inverse step-and-shoot treatment plans. The SLAM approach improved dose metrics compared to the clinical plans and Hamiltonian path continuous delivery plans. Beam-on times improved over clinical plans, and had mixed performance compared to Hamiltonian path continuous plans. The SLAM method is also shown to be robust to path selection inaccuracies, isocentre selection, and dose distribution. Conclusions: The SLAM method for continuous delivery provides decreased total treatment time and increased treatment quality compared to both clinical and inverse step-and-shoot plans, and outperforms existing path methods in treatment quality. It also accounts for uncertainty in treatment planning by accommodating inaccuracies.

  14. Robotic path-finding in inverse treatment planning for stereotactic radiosurgery with continuous dose delivery

    International Nuclear Information System (INIS)

    Vandewouw, Marlee M.; Aleman, Dionne M.; Jaffray, David A.

    2016-01-01

    Purpose: Continuous dose delivery in radiation therapy treatments has been shown to decrease total treatment time while improving the dose conformity and distribution homogeneity over the conventional step-and-shoot approach. The authors develop an inverse treatment planning method for Gamma Knife® Perfexion™ that continuously delivers dose along a path in the target. Methods: The authors’ method is comprised of two steps: find a path within the target, then solve a mixed integer optimization model to find the optimal collimator configurations and durations along the selected path. Robotic path-finding techniques, specifically, simultaneous localization and mapping (SLAM) using an extended Kalman filter, are used to obtain a path that travels sufficiently close to selected isocentre locations. SLAM is novelly extended to explore a 3D, discrete environment, which is the target discretized into voxels. Further novel extensions are incorporated into the steering mechanism to account for target geometry. Results: The SLAM method was tested on seven clinical cases and compared to clinical, Hamiltonian path continuous delivery, and inverse step-and-shoot treatment plans. The SLAM approach improved dose metrics compared to the clinical plans and Hamiltonian path continuous delivery plans. Beam-on times improved over clinical plans, and had mixed performance compared to Hamiltonian path continuous plans. The SLAM method is also shown to be robust to path selection inaccuracies, isocentre selection, and dose distribution. Conclusions: The SLAM method for continuous delivery provides decreased total treatment time and increased treatment quality compared to both clinical and inverse step-and-shoot plans, and outperforms existing path methods in treatment quality. It also accounts for uncertainty in treatment planning by accommodating inaccuracies.

  15. Peripheral photon and neutron doses from prostate cancer external beam irradiation.

    Science.gov (United States)

    Bezak, Eva; Takam, Rundgham; Marcu, Loredana G

    2015-12-01

    Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative. Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for (6)LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy(-1) for thyroid and 7.0±5.4 mSv Gy(-1) for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy(-1) for thyroid and 8.1±9.7 mSv Gy(-1) for colon. Paired (6)LiF:Mg,Cu,P and (7)LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. SU-E-T-432: A Rapid and Comprehensive Procedure for Daily Proton QA

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, T; Sun, B; Grantham, K; Knutson, N; Santanam, L; Goddu, S; Klein, E [Washington University, St. Louis, MO (United States)

    2014-06-01

    Purpose: The objective is to develop a rapid and comprehensive daily QA procedure implemented at the S. Lee Kling Proton Therapy Center at Barnes-Jewish Hospital. Methods: A scribed phantom with imbedded fiducials is used for checking lasers accuracy followed by couch isocentricity and for X-ray imaging congruence with isocenter. A Daily QA3 device (Sun Nuclear, FL) was used to check output, range and profiles. Five chambers in the central region possess various build-ups. After converting the thickness of the inherent build-ups into water equivalent thickness (WET) for proton, range of any beam can be checked with additional build-up on the Daily QA3 device. In our procedure, 3 beams from 3 bands (large, small and deep) with nominal range of 20 cm are checked daily. 17cm plastic water with WET of 16.92cm are used as additional build-up so that four chambers sit on the SOBP plateau at various depths and one sit on the distal fall off. Reading from the five chambers are fitted to an error function that has been parameterized to match the SOBP with the same nominal range. Shifting of the error function to maximize the correlation between measurements and the error function is deemed as the range shift from the nominal value. Results: We have found couch isocentricity maintained over 180 degrees. Imaging system exhibits accuracy in regard to imaging and mechanical isocenters. Ranges are within 1mm accuracy from measurements in water tank, and sensitive to change of sub-millimeter. Data acquired since the start of operation show outputs, profiles and range stay within 1% or 1mm from baselines. The whole procedure takes about 40 minutes. Conclusion: Taking advantage of the design of Daily QA3 device turns the device originally designed for photon and electron into a comprehensive and rapid tool for proton daily QA.

  17. The relative biological effectiveness of out-of-field dose

    International Nuclear Information System (INIS)

    Balderson, Michael; Koger, Brandon; Kirkby, Charles

    2016-01-01

    Purpose: using simulations and models derived from existing literature, this work investigates relative biological effectiveness (RBE) for out-of-field radiation and attempts to quantify the relative magnitudes of different contributing phenomena (spectral, bystander, and low dose hypersensitivity effects). Specific attention is paid to external beam radiotherapy treatments for prostate cancer. Materials and methods: using different biological models that account for spectral, bystander, and low dose hypersensitivity effects, the RBE was calculated for different points moving radially out from isocentre for a typical single arc VMAT prostate case. The RBE was found by taking the ratio of the equivalent dose with the physical dose. Equivalent doses were calculated by determining what physical dose would be necessary to produce the same overall biological effect as that predicted using the different biological models. Results: spectral effects changed the RBE out-of-field less than 2%, whereas response models incorporating low dose hypersensitivity and bystander effects resulted in a much more profound change of the RBE for out-of-field doses. The bystander effect had the largest RBE for points located just outside the edge of the primary radiation beam in the cranial caudal (z-direction) compared to low dose hypersensitivity and spectral effects. In the coplanar direction, bystander effect played the largest role in enhancing the RBE for points up to 8.75 cm from isocentre. Conclusions: spectral, bystander, and low dose hypersensitivity effects can all increase the RBE for out-of-field radiation doses. In most cases, bystander effects seem to play the largest role followed by low dose hypersensitivity. Spectral effects were unlikely to be of any clinical significance. Bystander, low dose hypersensitivity, and spectral effect increased the RBE much more in the cranial caudal direction (z-direction) compared with the coplanar directions. (paper)

  18. Initial Australian experience with daily ultrasound localisation for prostate radiotherapy

    International Nuclear Information System (INIS)

    Kneebone, A.; Fuller, M.W.; Williams, M.J.

    2003-01-01

    Variability in prostate position is a major problem in the delivery of external beam radiotherapy (EBRT). Daily ultrasound localisation prior to radiotherapy has become popular in the United States but to date has not been used clinically in Australia or New Zealand. Daily transabdominal ultrasound images through the prostate were acquired using the BAT ultrasound system. Contour data from the planning system is reconstructed at the same locations/angles as the BAT images. By overlaying the planned contours with the newly acquired images, the isocentre is adjusted to ensure that the prostate will be within the irradiated volume. After commissioning by Medical Physics, an initial pre-clinical trial period was adopted. This involved performing BAT alignments daily but treating to the planned isocentre in 30 patients. Eighty three percent of patients (25/30) had images judged to be of good or excellent quality by the reviewing radiation oncologist. It was noted that for each operator there was a period needed to build confidence/competence in both imaging and interpreting the images for the moves. The median scan time in addition to the normal patient set-up was 3.2 minutes (range=1.5-12.0 mins) with the second 15 patients scanned quicker than the first 15 (2.9 minutes versus 3.8 minutes). A summary of the movements recommended by the BAT system is contained in the table. We feel that daily prostate ultrasound localization offers a significant advance in delivering EBRT for prostate cancer. The incorporation of the system into clinical use, however, was not without difficulty and requires significant time and effort from therapists, physicists and medical staff. Further clinical evaluation of the unit is ongoing

  19. Dosimetry studies with TLDs for stereotactic radiation techniques for intraocular tumours

    International Nuclear Information System (INIS)

    Ertl, A.; Schoeggl, A.; Zehetmayer, M.; Kindl, P.; Hartl, R.

    1997-01-01

    Between March 1993 and January 1997, stereotactic radiation techniques were used to irradiate 66 intraocular tumour patients with the Gamma Knife (Leksell Gamma Knife, model B unit) at the University of Vienna, Austria. This study investigates the dosimetry for stereotactic irradiation of ocular structures. For the dosimetry program KULA 4.4, Gamma Knife stereotactic irradiation of the eye represents an extreme frontal skull position. In addition, irradiation of the eye may be performed in the usual supine position in exceptional cases only. With the patient in the prone position, the dose planning program has to calculate with a significantly large number of single-beam extrapolations. In our first experiment we measured the isocentre dose for eight different γ-angle positions, both in prone and supine positions, using TLD measurements in an Alderson head phantom. We found a maximum deviation of ±1.6% using these individually calibrated TLDs. In the second experiment we examined the dose cross profiles for the two most frequently used treatment positions (supine position, γ = 65 deg., and prone position, γ = 140 deg.). For this purpose we implanted a specially designed TLD array into the orbit of a human cadaver head. We found excellent agreement of the dose values measured for the isocentre as well as the posterior part of the eye with orbit with deviations of less than -2.7%. However, for the anterior part of the eye, deviations between computer-generated calculations and the TLD measurements were found to range up to -30%. These differences were noticed both for supine and prone positions. For the Gamma Knife stereotactic irradiation of ocular tumours or pathologies, precautions should be taken to avoid significant underdosage in the anterior part of the radiation field. (author)

  20. SU-E-T-432: A Rapid and Comprehensive Procedure for Daily Proton QA

    International Nuclear Information System (INIS)

    Zhao, T; Sun, B; Grantham, K; Knutson, N; Santanam, L; Goddu, S; Klein, E

    2014-01-01

    Purpose: The objective is to develop a rapid and comprehensive daily QA procedure implemented at the S. Lee Kling Proton Therapy Center at Barnes-Jewish Hospital. Methods: A scribed phantom with imbedded fiducials is used for checking lasers accuracy followed by couch isocentricity and for X-ray imaging congruence with isocenter. A Daily QA3 device (Sun Nuclear, FL) was used to check output, range and profiles. Five chambers in the central region possess various build-ups. After converting the thickness of the inherent build-ups into water equivalent thickness (WET) for proton, range of any beam can be checked with additional build-up on the Daily QA3 device. In our procedure, 3 beams from 3 bands (large, small and deep) with nominal range of 20 cm are checked daily. 17cm plastic water with WET of 16.92cm are used as additional build-up so that four chambers sit on the SOBP plateau at various depths and one sit on the distal fall off. Reading from the five chambers are fitted to an error function that has been parameterized to match the SOBP with the same nominal range. Shifting of the error function to maximize the correlation between measurements and the error function is deemed as the range shift from the nominal value. Results: We have found couch isocentricity maintained over 180 degrees. Imaging system exhibits accuracy in regard to imaging and mechanical isocenters. Ranges are within 1mm accuracy from measurements in water tank, and sensitive to change of sub-millimeter. Data acquired since the start of operation show outputs, profiles and range stay within 1% or 1mm from baselines. The whole procedure takes about 40 minutes. Conclusion: Taking advantage of the design of Daily QA3 device turns the device originally designed for photon and electron into a comprehensive and rapid tool for proton daily QA

  1. Dosimetric comparison of volumetric modulated arc therapy and linear accelerator-based radiosurgery for the treatment of one to four brain metastases.

    Science.gov (United States)

    Salkeld, Alison L; Unicomb, Kylie; Hayden, Amy J; Van Tilburg, Kevin; Yau, Shan; Tiver, Kenneth

    2014-12-01

    The purpose of this study is to compare and evaluate volumetric modulated arc therapy (VMAT) and linear accelerator-based radiosurgery (Linac RS) for the treatment of one to four brain metastases. Radiotherapy plans for 10 patients with 1 to 4 brain metastases that were planned and treated using conventional Linac RS were replanned using a mono-isocentric VMAT technique using two to four arcs. The same doses, target volumes and organs at risk (OAR) were used in both plans. The plans were evaluated for target volume coverage, dose conformity, homogeneity and dose to OAR. For VMAT plans, 18/19 brain metastases met acceptable Radiation Therapy Oncology Group (RTOG) radiosurgery dose coverage, homogeneity and conformity criteria. There was no observed difference between the mean homogeneity indices for VMAT and Linac RS plans. VMAT plans had a lower mean RTOG conformity index compared with the Linac RS plans (1.10 ± 0.06 versus 2.06 ± 1.02). For the OAR, there was no difference in maximal doses to the brain stem, optic chiasm or optic nerves. The volume of normal brain receiving 12 Gy was lower in the VMAT plans (13.3 cm(3) versus 23.1 cm(3) ) compared with the Linac RS plans. The mean total number of monitor units (MUs) was 31.3% less in the VMAT plans (5231.2 MU versus 3593.5 MU). Mono-isocentric VMAT plans using two to four arcs meet RTOG radiosurgery quality criteria in patients with one to four brain metastases, with an improvement in conformity and 12-Gy normal brain volume when compared with patients treated with Linac RS at our institution. © 2014 The Royal Australian and New Zealand College of Radiologists.

  2. RAPIDARC (RA) in the uterine cervical cancer; dosimetric gain vs 3D-Crt; RAPIDARC (RA) en el cancer de cervix uterino; ganancia dosimetrica vs 3D-CRT

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, J.; Garcia, B.; Quispe, K.; Gonzales, A.; Marquina, J., E-mail: jose.ramirez@aliada.com.pe [Clinica Aliada, Oncologia Integral, Av. Jose Galvez Barrenechea 1044, San Isidro, Lima (Peru)

    2014-08-15

    This work aims to quantitatively assess RAPIDARC (RA) treatments versus three dimensional-Conformal Radiation Therapy with field to field technique (3D-Crt-Fin F). 11 patients with cervical cancer treated at our institution radically or adjuvant clinical stages I-III B were evaluated. The prescribed dose was 50 Gy (2 Gy / Fr). The RA plans consisted of two isocentric complete arcs and conformational plans of 4 isocentric fields (previous, subsequent, right side and left side) with 3D-Crt-Fin F technique; both cases carried out ??in the Eclipse version 10 planner with calculation algorithm analytical anisotropic algorithm (AAA) and volumetric optimization software (for VMAT plans). Homogeneity indices (Hi), conformity indices (CI) Sigma indices (S-Index), monitor units (MU) and the time required for each treatment were compared. The mean age was 52 years (32-65) of the 11 patients 9 were clinical stages I-II B. The Hi varied from 0.052 for RA to 0.163 for 3D-Crt-Fin F (p = 0.009), and the CI between 1.005 and 1.35 (p = 0.26), the S-index from 1.2 to 3.7 (p = 0.001) and the H-index of 1.08 to 1.15 (p = 0.24). All dose limits in risk organs were met with a significant difference in the RA plans versus 3D-Crt-Fin F. In patients with cervical cancer the treatment plans quality with the indices aforementioned seems to be better with the RA technique, being observed a significant reduction of radiation to surrounding organs. (author)

  3. Characterization of 2 MeV, 4 MeV, 6 MeV and 18 MeV buildup caps for use with a 0.6 cubic centimeter thimble ionization chamber

    International Nuclear Information System (INIS)

    Salyer, R.L.; VanDenburg, J.W.; Prinja, A.K.; Kirby, T.; Busch, R.; Hong-Nian Jow

    1996-07-01

    The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm 3 thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm 3 active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response

  4. Hadron production in photon-photon collisions

    International Nuclear Information System (INIS)

    Pandita, P.N.; Singh, Y.

    1976-01-01

    We analyze deep-inelastic photon-photon collisions via the two-photon mechanism in electron-positron (-electron) colliding beams in a form especially suitable for experimental analysis. It is shown that by a helicity analysis similar to that used in electroproduction experiments, we can separate five of the eight structure functions describing the process γ* + γ* → hadrons. The helicity cross sections for this process and for the process with one real photon (inelastic electron-photon scattering) are related to structure functions, and are evaluated using quark light-cone algebra. There are anomalous contributions to the structure functions for the inelastic electron-photon scattering which arise both in parton as well as generalized vector-meson-dominance models. This suggests a connection between these two types of models for photon-photon scattering. Further, we use vector-meson dominance to construct a sum rule for sigma/sub gamma//sub gamma/ /sub arrow-right/ from which it is estimated that roughly 20% of the cross section should be built up from higher-mass vector states. Using a spectral representation for the total transverse cross section, and the ''aligned-jet'' vector-dominance model we achieve a connection, via a ''correspondence principle,'' with the parton model for the hadron multiplicities in photon-photon collisions. We also comment on inclusive pion multiplicities and the approach to scaling for photon-photon processes in the light-cone algebra

  5. Rotational symmetry breaking and topological phase transition in the exciton-polariton condensate of gapped 2D Dirac material

    Science.gov (United States)

    Lee, Ki Hoon; Lee, Changhee; Jeong, Jae-Seung; Min, Hongki; Chung, Suk Bum

    For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon coupling can lead to the emergence of bosonic quasiparticles consisting of the exciton and the cavity photon known as polariton, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped Dirac material such as the transition metal dichalcogenide (TMD) MoS2 or WTe2. Specifically, in forming excitons, the electron-photon coupling from the optical selection rule due to the Berry phase competes against, rather than cooperates with, the Coulomb interaction. We find that this competition gives rise to the spontaneous breaking of the rotational symmetry in the polariton condensate and also drives topological phase transition, both novel features in polariton condensation. We also investigate the possible detection of this competition through photoluminescence. This work was supported in part by the Institute for Basic Science of Korea (IBS) under Grant IBS-R009-Y1 and by the National Research Foundation of Korea (NRF) under the Basic Science Research Program Grant No. 2015R1D1A1A01058071.

  6. Ab Initio Optimized Effective Potentials for Real Molecules in Optical Cavities: Photon Contributions to the Molecular Ground State

    Science.gov (United States)

    2018-01-01

    We introduce a simple scheme to efficiently compute photon exchange-correlation contributions due to the coupling to transversal photons as formulated in the newly developed quantum-electrodynamical density-functional theory (QEDFT).1−5 Our construction employs the optimized-effective potential (OEP) approach by means of the Sternheimer equation to avoid the explicit calculation of unoccupied states. We demonstrate the efficiency of the scheme by applying it to an exactly solvable GaAs quantum ring model system, a single azulene molecule, and chains of sodium dimers, all located in optical cavities and described in full real space. While the first example is a two-dimensional system and allows to benchmark the employed approximations, the latter two examples demonstrate that the correlated electron-photon interaction appreciably distorts the ground-state electronic structure of a real molecule. By using this scheme, we not only construct typical electronic observables, such as the electronic ground-state density, but also illustrate how photon observables, such as the photon number, and mixed electron-photon observables, for example, electron–photon correlation functions, become accessible in a density-functional theory (DFT) framework. This work constitutes the first three-dimensional ab initio calculation within the new QEDFT formalism and thus opens up a new computational route for the ab initio study of correlated electron–photon systems in quantum cavities. PMID:29594185

  7. Optimisation of the level-1 calorimeter trigger at ATLAS for Run II

    Energy Technology Data Exchange (ETDEWEB)

    Suchek, Stanislav [Kirchhoff-Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg (Germany); Collaboration: ATLAS-Collaboration

    2015-07-01

    The Level-1 Calorimeter Trigger (L1Calo) is a central part of the ATLAS Level-1 Trigger system, designed to identify jet, electron, photon, and hadronic tau candidates, and to measure their transverse energies, as well total transverse energy and missing transverse energy. The optimisation of the jet energy resolution is an important part of the L1Calo upgrade for Run II. A Look-Up Table (LUT) is used to translate the electronic signal from each trigger tower to its transverse energy. By optimising the LUT calibration we can achieve better jet energy resolution and better performance of the jet transverse energy triggers, which are vital for many physics analyses. In addition, the improved energy calibration leads to significant improvements of the missing transverse energy resolution. A new Multi-Chip Module (MCM), as a part of the L1Calo upgrade, provides two separate LUTs for jets and electrons/photons/taus, allowing to optimise jet transverse energy and missing transverse energy separately from the electromagnetic objects. The optimisation is validated using jet transverse energy and missing transverse energy triggers turn-on curves and rates.

  8. MCNP6.1 simulations for low-energy atomic relaxation: Code-to-code comparison with GATEv7.2, PENELOPE2014, and EGSnrc

    Science.gov (United States)

    Jung, Seongmoon; Sung, Wonmo; Lee, Jaegi; Ye, Sung-Joon

    2018-01-01

    Emerging radiological applications of gold nanoparticles demand low-energy electron/photon transport calculations including details of an atomic relaxation process. Recently, MCNP® version 6.1 (MCNP6.1) has been released with extended cross-sections for low-energy electron/photon, subshell photoelectric cross-sections, and more detailed atomic relaxation data than the previous versions. With this new feature, the atomic relaxation process of MCNP6.1 has not been fully tested yet with its new physics library (eprdata12) that is based on the Evaluated Atomic Data Library (EADL). In this study, MCNP6.1 was compared with GATEv7.2, PENELOPE2014, and EGSnrc that have been often used to simulate low-energy atomic relaxation processes. The simulations were performed to acquire both photon and electron spectra produced by interactions of 15 keV electrons or photons with a 10-nm-thick gold nano-slab. The photon-induced fluorescence X-rays from MCNP6.1 fairly agreed with those from GATEv7.2 and PENELOPE2014, while the electron-induced fluorescence X-rays of the four codes showed more or less discrepancies. A coincidence was observed in the photon-induced Auger electrons simulated by MCNP6.1 and GATEv7.2. A recent release of MCNP6.1 with eprdata12 can be used to simulate the photon-induced atomic relaxation.

  9. Monolithically Integrated Ge-on-Si Active Photonics

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2014-07-01

    Full Text Available Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs, electroabsorption modulators (EAMs, and laser diodes (LDs, and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.

  10. Triggering on electrons and photons with CMS

    Directory of Open Access Journals (Sweden)

    Zabi Alexandre

    2012-06-01

    Full Text Available Throughout the year 2011, the Large Hadron Collider (LHC has operated with an instantaneous luminosity that has risen continually to around 4 × 1033cm−2s−1. With this prodigious high-energy proton collisions rate, efficient triggering on electrons and photons has become a major challenge for the LHC experiments. The Compact Muon Solenoid (CMS experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 106. The first level (L1 is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger (HLT combines fine-grain information from all sub-detectors. In this intense hadronic environment, the L1 electron/photon trigger provides a powerful tool to select interesting events. It is based upon information from the Electromagnetic Calorimeter (ECAL, a high-resolution detector comprising 75848 lead tungstate (PbWO4 crystals in a “barrel” and two “endcaps”. The performance as well as the optimization of the electron/photon trigger are presented.

  11. Gauge-invariant dynamical quantities of QED with decomposed gauge potentials

    International Nuclear Information System (INIS)

    Zhou Baohua; Huang Yongchang

    2011-01-01

    We discover an inner structure of the QED system; i.e., by decomposing the gauge potential into two orthogonal components, we obtain a new expansion of the Lagrangian for the electron-photon system, from which, we realize the orthogonal decomposition of the canonical momentum conjugate to the gauge potential with the canonical momentum's two components conjugate to the gauge potential's two components, respectively. Using the new expansion of Lagrangian and by the general method of field theory, we naturally derive the gauge invariant separation of the angular momentum of the electron-photon system from Noether theorem, which is the rational one and has the simplest form in mathematics, compared with the other four versions of the angular momentum separation available in literature. We show that it is only the longitudinal component of the gauge potential that is contained in the orbital angular momentum of the electron, as Chen et al. have said. A similar gauge invariant separation of the momentum is given. The decomposed canonical Hamiltonian is derived, from which we construct the gauge invariant energy operator of the electron moving in the external field generated by a proton [Phys. Rev. A 82, 012107 (2010)], where we show that the form of the kinetic energy containing the longitudinal part of the gauge potential is due to the intrinsic requirement of the gauge invariance. Our method provides a new perspective to look on the nucleon spin crisis and indicates that this problem can be solved strictly and systematically.

  12. Recent developments in discrete ordinates electron transport

    International Nuclear Information System (INIS)

    Morel, J.E.; Lorence, L.J. Jr.

    1986-01-01

    The discrete ordinates method is a deterministic method for numerically solving the Boltzmann equation. It was originally developed for neutron transport calculations, but is routinely used for photon and coupled neutron-photon transport calculations as well. The computational state of the art for coupled electron-photon transport (CEPT) calculations is not as developed as that for neutron transport calculations. The only production codes currently available for CEPT calculations are condensed-history Monte Carlo codes such as the ETRAN and ITS codes. A deterministic capability for production calculations is clearly needed. In response to this need, we have begun the development of a production discrete ordinates code for CEPT calculations. The purpose of this paper is to describe the basic approach we are taking, discuss the current status of the project, and present some new computational results. Although further characterization of the coupled electron-photon discrete ordinates method remains to be done, the results to date indicate that the discrete ordinates method can be just as accurate and from 10 to 100 times faster than the Monte Carlo method for a wide variety of problems. We stress that these results are obtained with standard discrete ordinates codes such as ONETRAN. It is clear that even greater efficiency can be obtained by developing a new generation of production discrete ordinates codes specifically designed to solve the Boltzmann-Fokker-Planck equation. However, the prospects for such development in the near future appear to be remote

  13. Penelope-2006: a code system for Monte Carlo simulation of electron and photon transport

    International Nuclear Information System (INIS)

    2006-01-01

    The computer code system PENELOPE (version 2006) performs Monte Carlo simulation of coupled electron-photon transport in arbitrary materials for a wide energy range, from a few hundred eV to about 1 GeV. Photon transport is simulated by means of the standard, detailed simulation scheme. Electron and positron histories are generated on the basis of a mixed procedure, which combines detailed simulation of hard events with condensed simulation of soft interactions. A geometry package called PENGEOM permits the generation of random electron-photon showers in material systems consisting of homogeneous bodies limited by quadric surfaces, i.e. planes, spheres, cylinders, etc. This report is intended not only to serve as a manual of the PENELOPE code system, but also to provide the user with the necessary information to understand the details of the Monte Carlo algorithm. These proceedings contain the corresponding manual and teaching notes of the PENELOPE-2006 workshop and training course, held on 4-7 July 2006 in Barcelona, Spain. (author)

  14. Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

    2011-03-15

    Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group

  15. Characterization of an extendable multi-leaf collimator for clinical electron beams

    International Nuclear Information System (INIS)

    O'Shea, Tuathan P; Foley, Mark J; Ge Yuanyuan; Faddegon, Bruce A

    2011-01-01

    An extendable x-ray multi-leaf collimator (eMLC) is investigated for collimation of electron beams on a linear accelerator. The conventional method of collimation using an electron applicator is impractical for conformal, modulated and mixed beam therapy techniques. An eMLC would allow faster, more complex treatments with potential for reduction in dose to organs-at-risk and critical structures. The add-on eMLC was modelled using the EGSnrc Monte Carlo code and validated against dose measurements at 6–21 MeV with the eMLC mounted on a Siemens Oncor linear accelerator at 71.6 and 81.6 cm source-to-collimator distances. Measurements and simulations at 8.4–18.4 cm airgaps showed agreement of 2%/2 mm. The eMLC dose profiles and percentage depth dose curves were compared with standard electron applicator parameters. The primary differences were a wider penumbra and up to 4.2% reduction in the build-up dose at 0.5 cm depth, with dose normalized on the central axis. At 90 cm source-to-surface distance (SSD)-–relevant to isocentric delivery-–the applicator and eMLC penumbrae agreed to 0.3 cm. The eMLC leaves, which were 7 cm thick, contributed up to 6.3% scattered electron dose at the depth of maximum dose for a 10 × 10 cm 2 field, with the thick leaves effectively eliminating bremsstrahlung leakage. A Monte Carlo calculated wedge shaped dose distribution generated with all six beam energies matched across the maximum available eMLC field width demonstrated a therapeutic (80% of maximum dose) depth range of 2.1–6.8 cm. Field matching was particularly challenging at lower beam energies (6–12 MeV) due to the wider penumbrae and angular distribution of electron scattering. An eMLC isocentric electron breast boost was planned and compared with the conventional applicator fixed SSD plan, showing similar target coverage and dose to critical structures. The mean dose to the target differed by less than 2%. The low bremsstrahlung dose from the 7 cm thick MLC leaves

  16. Implementation of virtual simulation with a wide-bore multislice helcalct scanner

    International Nuclear Information System (INIS)

    Greer, P.; Kenny, J.

    2004-01-01

    relative to the laser plane. 4) Offsets in the CT and isocentre coordinates occur during the transfer to Pinnacle, however the anatomical locations of the beams are transferred correctly. Plan names and identifiers are not imported into Pinnacle making plan identification problematic. Scanning should wherever possible be performed within the 50 cm diameter fully sampled region due to inferior quality and large variation in CT number. The isocentre defined in CT coordinates within the patient during virtual simulation is ∼4 mm above the tattoos marked using the external lasers without patient sag, therefore couch-height set-up must be used for virtual simulation patients. The GE scanner and ASim software export the DICOM standard patient-specific coordinate system, while the Pinnacle RTFS currently does not. It is advisable to print hard-copies of plan details and isocentre location as transfer of the correct plan to Pinnacle is otherwise difficult to verify. No major problems resulting from the lack of a conventional simulator within the department have arisen to date. Copyright (2004) Australasian College of Physical Scientists and Engineers in Medicine

  17. Calculation of entrance exposed area from recorded images in cardiac diagnostic and interventional procedures

    International Nuclear Information System (INIS)

    Bibbo, G.; Balman, D.

    2000-01-01

    With increasing number of interventional radiological procedures performed on patients of all ages, it is important to determine the skin entrance dose of patients to limit the side effects of radiation. In most cases the skin dose is measured using thermoluminescent detectors (TLD). However, these detectors need to be placed in the radiation field on the skin of the patient, which may interfere with the procedure. Also, not all radiological practices are equipped with TLD readers which are expensive or have staff with the appropriate knowledge and expertise to be able to make use of TLD. The alternative to TLD is to use the dose area product (DAP) measured with a diamentor fitted to the angiography x-ray equipment. The difficulties in using DAP to calculate skin dose is that the irradiated area of the skin is not known. The area could change in size and location during the procedure as the radiologist/medical specialist varies the collimation and region of interest. For angiography equipment the distance between the anode and image intensifier is variable, as is the height of the examination table. The only point of reference is the isocentre. With recorded images it is possible to determine the irradiated area of the patient at the isocentre plane using the stenosis algorithm. The recorded image is calibrated such that it corresponds to the physical size in the plane of the isocentre. For non-recorded images, it may be necessary to assume that collimation has not changed and that the irradiated area is the same as that shown on the recorded images. The Women's and Children's Hospital has a Toshiba DFP2000 Biplane Digital Imaging system used for all cardiac and general angiography and interventional procedures. With this system the exposure factors (kVp, mA, field sizes) are recorded with the images. The source to image distance (SID), magnification factor (calibration factor of the recorded images) and angle of rotation are displayed on the Display Panel of the

  18. Helical Tomotherapy-Based STAT RT: Dosimetric Evaluation for Clinical Implementation of a Rapid Radiation Palliation Program

    International Nuclear Information System (INIS)

    McIntosh, Alyson; Dunlap, Neal; Sheng, Ke; Geezey, Constance; Turner, Benton; Blackhall, Leslie; Weiss, Geoffrey; Lappinen, Eric; Larner, James M.; Read, Paul W.

    2010-01-01

    Helical tomotherapy-based STAT radiation therapy (RT) uses an efficient software algorithm for rapid intensity-modulated treatment planning, enabling conformal radiation treatment plans to be generated on megavoltage computed tomography (MVCT) scans for CT simulation, treatment planning, and treatment delivery in one session. We compared helical tomotherapy-based STAT RT dosimetry with standard linac-based 3D conformal plans and standard helical tomotherapy-based intensity-modulated radiation therapy (IMRT) dosimetry for palliative treatments of whole brain, a central obstructive lung mass, multilevel spine disease, and a hip metastasis. Specifically, we compared the conformality, homogeneity, and dose with regional organs at risk (OARs) for each plan as an initial step in the clinical implementation of a STAT RT rapid radiation palliation program. Hypothetical planning target volumes (PTVs) were contoured on an anthropomorphic phantom in the lung, spine, brain, and hip. Treatment plans were created using three planning techniques: 3D conformal on Pinnacle 3 , helical tomotherapy, and helical tomotherapy-based STAT RT. Plan homogeneity, conformality, and dose to OARs were analyzed and compared. STAT RT and tomotherapy improved conformality indices for spine and lung plans (CI spine = 1.21, 1.17; CI lung = 1.20, 1.07, respectively) in comparison with standard palliative anteroposterior/posteroanterior (AP/PA) treatment plans (CI spine = 7.01, CI lung = 7.30), with better sparing of heart, esophagus, and spinal cord. For palliative whole-brain radiotherapy, STAT RT and tomotherapy reduced maximum and mean doses to the orbits and lens (maximum/mean lens dose: STAT RT = 2.94/2.65 Gy, tomotherapy = 3.13/2.80 Gy, Lateral opposed fields = 7.02/3.65 Gy), with an increased dose to the scalp (mean scalp dose: STAT RT = 16.19 Gy, tomotherapy = 15.61 Gy, lateral opposed fields = 14.01 Gy). For bony metastatic hip lesions, conformality with both tomotherapy techniques (CI = 1

  19. A pencil beam dose calculation model for CyberKnife system

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Bin; Li, Yongbao; Liu, Bo; Zhou, Fugen [Image Processing Center, Beihang University, Beijing 100191 (China); Xu, Shouping [Department of Radiation Oncology, PLA General Hospital, Beijing 100853 (China); Wu, Qiuwen, E-mail: Qiuwen.Wu@Duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2016-10-15

    Purpose: CyberKnife system is initially equipped with fixed circular cones for stereotactic radiosurgery. Two dose calculation algorithms, Ray-Tracing and Monte Carlo, are available in the supplied treatment planning system. A multileaf collimator system was recently introduced in the latest generation of system, capable of arbitrarily shaped treatment field. The purpose of this study is to develop a model based dose calculation algorithm to better handle the lateral scatter in an irregularly shaped small field for the CyberKnife system. Methods: A pencil beam dose calculation algorithm widely used in linac based treatment planning system was modified. The kernel parameters and intensity profile were systematically determined by fitting to the commissioning data. The model was tuned using only a subset of measured data (4 out of 12 cones) and applied to all fixed circular cones for evaluation. The root mean square (RMS) of the difference between the measured and calculated tissue-phantom-ratios (TPRs) and off-center-ratio (OCR) was compared. Three cone size correction techniques were developed to better fit the OCRs at the penumbra region, which are further evaluated by the output factors (OFs). The pencil beam model was further validated against measurement data on the variable dodecagon-shaped Iris collimators and a half-beam blocked field. Comparison with Ray-Tracing and Monte Carlo methods was also performed on a lung SBRT case. Results: The RMS between the measured and calculated TPRs is 0.7% averaged for all cones, with the descending region at 0.5%. The RMSs of OCR at infield and outfield regions are both at 0.5%. The distance to agreement (DTA) at the OCR penumbra region is 0.2 mm. All three cone size correction models achieve the same improvement in OCR agreement, with the effective source shift model (SSM) preferred, due to their ability to predict more accurately the OF variations with the source to axis distance (SAD). In noncircular field validation

  20. Linear accelerator radiosurgery for vestibular schwannomas: Results of medium-term follow-up.

    Science.gov (United States)

    Ellenbogen, Jonathan R; Waqar, Mueez; Kinshuck, Andrew J; Jenkinson, Michael D; Lesser, Tristram H J; Husband, David; Javadpour, Mohsen

    2015-01-01

    To examine tumour control, via volume changes, and the complications of linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) treatment of vestibular schwannomas (VSs) on medium-term follow-up. Between September 2003 and November 2009 fifty consecutive patients with VSs treated with SRS using a marginal dose of 12.5 Gy utilizing a LINAC equipped with a micro-multileaf collimator were identified. Evaluation included serial magnetic resonance imaging (MRI), and neurological and hearing examinations. The median tumour volume at treatment was 2.4 (range: 0.24-10.59) cm3. The intracranial diameter of the tumours ranged between 7.7 and 28.7 (median: 15.8) mm. Follow-up MRI was available for analysis on 49 patients. The median radiological follow-up period was 5.8 (range: 1.4-9.2) years. The median tumour volume at last follow-up was 1.1 (range: 0.03-5.3) cm3. VS decreased in size in 45 (90%) patients, with a median reduction in tumour volume of 1.46 (range: 0.06-9.29) cm3 or a median tumour size reduction of 59% of the baseline (range: 6-90%) in these patients. VS remained stable in 2 patients and increased in size in 2 patients. Only 1 patient (2%) required additional intervention (surgery). 15 patients had useful hearing pre-treatment; 10 post-treatment pure-tone audiograms of these patients were available. 5 (50%) patients still had useful hearing post treatment. Non-auditory adverse radiation effects included new (House-Brackmann grade II) or worsened facial nerve palsy (House-Brackmann grade II to grade V) in 2 (4%) patients and trigeminal sensory disturbance in 2 (4%) patients. At medium term, the vast majority of VSs treated with LINAC-based SRS exhibit tumour shrinkage. The slightly higher rate of facial nerve palsy compared with Gamma Knife surgery (GKS) results may be related to the learning curve. Other complications were similar to reported GKS results for VSs of comparable sizes.

  1. SU-E-J-139: One Institution’s Experience with Surface Imaging in Proton Therapy

    International Nuclear Information System (INIS)

    Zhao, L; Singh, H; Zheng, Y

    2015-01-01

    Purpose: X-ray system is commonly used for IGRT in proton therapy, however image acquisition not only increases treatment time but also adds imaging dose. We studied a 3D surface camera system (AlignRT) performance for proton therapy. Methods: System accuracy was evaluated with rigid phantom under two different camera location configurations. For initial clinical applications, post mastectomy chest wall and partial breast treatments were studied. X-ray alignment was used as our ground truth. Our studies included: 1) comparison of daily patient setup shifts between X-ray alignment and SI calculation; 2) interfractional breast surface position variation when aligning to bony landmark on X-ray; 3) absolute positioning using planning CT DICOM data; 4) shifts for multi-isocenter treatment plan; 5) couch isocentric rotation accuracy. Results: Camera locations affected the system performance. After camera relocation, the accuracy of the system for the rigid phantom was within 1 mm (fixed couch), and 1.5 mm (isocentric rotation). For intrafractional patient positioning, X-ray and AlignRT shifts were highly correlated (r=0.99), with the largest difference (mean ± SD) in the longitudinal direction (2.14 ± 1.02 mm). For interfractional breast surface variation and absolute positioning, there were still larger disagreements between the two modalities due to different focus on anatomical landmarks, and 95% of the data lie within 5mm with some outliers at 7 mm–9 mm. For multi-isocenter shifts, the difference was 1 ± 0.56 mm over an 11 cm shift in longitudinal direction. For couch rotation study, the differences was 1.36 ± 1.0 mm in vertical direction, 3.04 ± 2.11 mm in longitudinal direction, and 2.10 ± 1.66 mm in lateral direction, with all rotation differences < 1.5 degree. Conclusion: Surface imaging is promising for intrafractional treatment application in proton therapy to reduce X-ray frequency. However the interfractional discrepancy between the X-ray and SI

  2. SU-E-J-139: One Institution’s Experience with Surface Imaging in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, L; Singh, H; Zheng, Y [ProCure Proton Therapy Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: X-ray system is commonly used for IGRT in proton therapy, however image acquisition not only increases treatment time but also adds imaging dose. We studied a 3D surface camera system (AlignRT) performance for proton therapy. Methods: System accuracy was evaluated with rigid phantom under two different camera location configurations. For initial clinical applications, post mastectomy chest wall and partial breast treatments were studied. X-ray alignment was used as our ground truth. Our studies included: 1) comparison of daily patient setup shifts between X-ray alignment and SI calculation; 2) interfractional breast surface position variation when aligning to bony landmark on X-ray; 3) absolute positioning using planning CT DICOM data; 4) shifts for multi-isocenter treatment plan; 5) couch isocentric rotation accuracy. Results: Camera locations affected the system performance. After camera relocation, the accuracy of the system for the rigid phantom was within 1 mm (fixed couch), and 1.5 mm (isocentric rotation). For intrafractional patient positioning, X-ray and AlignRT shifts were highly correlated (r=0.99), with the largest difference (mean ± SD) in the longitudinal direction (2.14 ± 1.02 mm). For interfractional breast surface variation and absolute positioning, there were still larger disagreements between the two modalities due to different focus on anatomical landmarks, and 95% of the data lie within 5mm with some outliers at 7 mm–9 mm. For multi-isocenter shifts, the difference was 1 ± 0.56 mm over an 11 cm shift in longitudinal direction. For couch rotation study, the differences was 1.36 ± 1.0 mm in vertical direction, 3.04 ± 2.11 mm in longitudinal direction, and 2.10 ± 1.66 mm in lateral direction, with all rotation differences < 1.5 degree. Conclusion: Surface imaging is promising for intrafractional treatment application in proton therapy to reduce X-ray frequency. However the interfractional discrepancy between the X-ray and SI

  3. Evaluation of permanent I-125 prostate implants using radiography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Moerland, Marinus A.; Wijrdeman, Harm K.; Beersma, Robert; Bakker, Chris J.G.; Battermann, Jan J.

    1997-01-01

    Purpose: The aim of this study is the evaluation of permanent I-125 prostate implants using radiography and magnetic resonance imaging (MRI). Methods and Materials: Twenty-one patients underwent radiography on the simulator and MRI within 3 days after implantation of the I-125 seeds. Isocentric radiographs were used for reconstruction of the seed distribution, after which registration with the seed-induced signal voids on MRI provided the seed positions in relation to the prostate. The prostate was contoured on the transversal magnetic resonance images, and dose-volume histograms were computed to evaluate the implants. The validity of the ellipsoidal prostate volume approximation, as applied in preimplant dose calculation, was assessed by comparison of ellipsoidal volumes given by prostate width, height, and length and prostate volumes obtained by a slice-by-slice contouring method, both on postimplant MRI. Prostate volume changes due to postimplant prostate swelling were assessed from radiographs taken at 3 days and 1 month after the implantation. Results: The seeds were readily identified on T 1 -weighted spin-echo images and matched with the seed distribution reconstructed from the isocentric radiographs. The matching error, averaged over 21 patients, amounted to 1.8 ± 0.4 mm (mean ± standard deviation). The fractions of the prostate volumes receiving the prescribed matched peripheral dose (MPD) ranged from 32 to 71% (mean ± standard deviation: 60 ± 10%). Prostate volumes, obtained by the contouring method on postimplant MRI, were a factor 1.5 ± 0.3 larger than the ellipsoidal volumes given by the prostate dimensions on postimplant MRI. Prostate volumes 3 days after the implantation were a factor 1.3 ± 0.2 larger than the prostate volumes 1 month after the implantation. Registration of the reconstructed seed distribution and the MR images showed inaccuracies in seed placement, for example, two or more seeds clustering together or seeds outside the prostate

  4. SU-E-T-229: Craniospinal Radiotherapy Planning with VMAT, Two First Years Experience

    Energy Technology Data Exchange (ETDEWEB)

    Lliso, F; Carmona, V; Gimeno, J; Candela-Juan, C; Bautista, J [La Fe University and Polytechnic Hospital, Valencia, Valencia (Spain); Richart, J [ITIC, Hospital Clinica Benidorm, Benidorm, Alicante (Spain); Perez-Calatayud, J [La Fe University and Polytechnic Hospital, Valencia, Valencia (Spain); ITIC, Hospital Clinica Benidorm, Benidorm, Alicante (Spain)

    2015-06-15

    Purpose: To describe how we moved to VMAT in the craniospinal radiotherapy planning process, the actual procedure details, and the results for the patients treated. Methods: Twelve patients underwent craniospinal irradiation with the new procedure, based on the paper by Lee et al. (IJROBP 82, 2012), with some additional modifications. Patients were treated in supine position in Varian Clinac iX linacs with 6 MV RapidArc; prescription doses ranged from 23.4 to 40 Gy (13 to 20 fractions); depending on the PTV length, 2 or 3 isocenters were used, all coordinates being equal except the longitudinal one, setting a few centimeter-long overlapping region; 2 arcs (RA) sharing isocentre for the cranial region, RA1 encompassing cranium and superior spinal region, and RA2 intended to improve conformity, only for cranium; for spine, 1 or 2 isocenters were employed; optimization was performed with Eclipse (V 13.0) using AAA algorithm, establishing sets of optimization parameters to give high conformity while sparing OAR. In pediatric patients, homogeneous irradiation of the vertebrae was also required.Conformity (CI) and heterogeneity (HI) indices (same as Lee et al.), and mean and maximum doses for OAR were calculated. Several pre-treatment verification methods were used: Octavius4D (PTW) for each isocentre, point dose at the junction region, Portal Dosimetry (when possible), and independent MU verification software (Diamond, PTW). Results: CI median value was 1.02 (0.99–1.07) and HI, 1.07 (1.06–1.09); a great reduction was observed for CI and OAR mean doses with respect to Lee et al. data; median maximum eye lens dose was 7.3 Gy (4.0–12.0); mean LungV20Gy was 1.9%; in children, vertebrae were homogeneously irradiated (D95%=20.8 Gy, Dmean= 23.2 Gy).All pre-treatment verifications were found within our action levels except for Portal Dosimetry. Conclusion: A RapidArc planning process for craniospinal axis irradiation has been implemented with significant advantages on

  5. Two-dimensional versus three-dimensional treatment planning of tangential breast irradiation

    International Nuclear Information System (INIS)

    Damen, E.M.F.; Bruinvis, I.A.D.; Mijnheer, B.J.

    1995-01-01

    Purpose: Full three-dimensional (3-D) treatment planning requires 3-D patient contours and density information, derived either from CT scanning or from other 3-D contouring methods. These contouring techniques are time consuming, and are often not available or cannot be used. Two-dimensional (2-D) treatment planning can be performed using only a few patient contours, made with much simpler techniques, in combination with simulator images for estimating the lung position. In order to investigate the need for full 3-D planning, we compared the performance of both a 2-D and a 3-D planning system in calculating absolute dose values and relative dose distributions in tangential breast irradiation. Methods: Two breast-shaped phantoms were used in this study. The first phantom consists of a polyethylene mould, filled with water and cork to mimic the lung. An ionization chamber can be inserted in the phantom at fixed positions. The second phantom is made of 25 transverse slices of polystyrene and cork, made with a computerized milling machine from CT information. In this phantom, films can be inserted in three sagittal planes. Both phantoms have been irradiated with two tangential 8 MV photon beams. The measured dose distribution has been compared with the dose distribution predicted by the two planning systems. Results: In the central plane, the 3-D planning system predicts the absolute dose with an accuracy of 0.5 - 4%. The dose at the isocentre of the beams agrees within 0.5% with the measured dose. The 2-D system predicts the dose with an accuracy of 0.9 - 3%. The dose calculated at the isocentre is 2.6% higher than the measured dose, because missing lateral scatter is not taken into account in this planning system. In off-axis planes, the calculated absolute dose agrees with the measured dose within 4% for the 2-D system and within 6% for the 3-D system. However, the relative dose distribution is predicted better by the 3-D planning system. Conclusions: This study

  6. Is ad-hoc plan adaptation based on 2-Step IMRT feasible?

    International Nuclear Information System (INIS)

    Bratengeier, Klaus; Polat, Buelent; Gainey, Mark; Grewenig, Patricia; Meyer, Juergen; Flentje, Michael

    2009-01-01

    Background: The ability of a geometry-based method to expeditiously adapt a '2-Step' step and shoot IMRT plan was explored. Both changes of the geometry of target and organ at risk have to be balanced. A retrospective prostate planning study was performed to investigate the relative benefits of beam segment adaptation to the changes in target and organ at risk coverage. Methods: Four patients with six planning cases with extraordinarily large deformations of rectum and prostate were chosen for the study. A 9-field IMRT plan (A) using 2-Step IMRT segments was planned on an initial CT study. The plan had to fulfil all the requirements of a conventional high-quality step and shoot IMRT plan. To adapt to changes of the anatomy in a further CT data set, three approaches were considered: the original plan with optimized isocentre position (B), a newly optimized plan (C) and the original plan, adapted using the 2-Step IMRT optimization rules (D). DVH parameters were utilized for quantification of plan quality: D 99 for the CTV and the central planning target volume (PTV), D 95 for an outer PTV, V 95 , V 80 and V 50 for rectum and bladder. Results: The adapted plan (D) achieved almost the same target coverage as the newly optimized plan (C). Target coverage for plan B was poor and for the organs at risk, the rectum V 80 was slightly increased. The volume with more than 95% of the target dose (V 95 ) was 1.5 ± 1.5 cm 3 for the newly optimized plan (C), compared to 2.2 ± 1.3 cm 3 for the original plan (A) and 7.2 ± 4.8 cm 3 (B) on the first and the second CT, respectively. The adapted plan resulted in 4.3 ± 2.1 cm 3 (D), an intermediate dose load to the rectum. All other parameters were comparable for the newly optimized and the adapted plan. Conclusions: The first results for adaptation of interfractional changes using the 2-Step IMRT algorithm are encouraging. The plans were superior to plans with optimized isocentre position and only marginally inferior to a newly

  7. SU-E-T-226: Junction Free Craniospinal Irradiation in Linear Accelerator Using Volumetric Modulated Arc Therapy : A Novel Technique Using Dose Tapering

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, B; Roy, S; Paul, S; Munshi, A; Roy, Shilpi; Jassal, K; Ganesh, T; Mohanti, BK [Fortis Memorial Research Institute, Gurgaon (India)

    2014-06-01

    Purpose: Spatially separated fields are required for craniospinal irradiation due to field size limitation in linear accelerator. Field junction shits are conventionally done to avoid hot or cold spots. Our study was aimed to demonstrate the feasibility of junction free irradiation plan of craniospinal irradiation (CSI) for Meduloblastoma cases treated in linear accelerator using Volumetric modulated arc therapy (VMAT) technique. Methods: VMAT was planned using multiple isocenters in Monaco V 3.3.0 and delivered in Elekta Synergy linear accelerator. A full arc brain and 40° posterior arc spine fields were planned using two isocentre for short (<1.3 meter height ) and 3 isocentres for taller patients. Unrestricted jaw movement was used in superior-inferior direction. Prescribed dose to PTV was achieved by partial contribution from adjacent beams. A very low dose gradient was generated to taper the isodoses over a long length (>10 cm) at the conventional field junction. Results: In this primary study five patients were planned and three patients were delivered using this novel technique. As the dose contribution from the adjacent beams were varied (gradient) to create a complete dose distribution, therefore there is no specific junction exists in the plan. The junction were extended from 10–14 cm depending on treatment plan. Dose gradient were 9.6±2.3% per cm for brain and 7.9±1.7 % per cm for spine field respectively. Dose delivery error due to positional inaccuracy was calculated for brain and spine field for ±1mm, ±2mm, ±3mm and ±5 mm were 1%–0.8%, 2%–1.6%, 2.8%–2.4% and 4.3%–4% respectively. Conclusion: Dose tapering in junction free CSI do not require a junction shift. Therefore daily imaging for all the field is also not essential. Due to inverse planning dose to organ at risk like thyroid kidney, heart and testis can be reduced significantly. VMAT gives a quicker delivery than Step and shoot or dynamic IMRT.

  8. SU-F-T-459: ArcCHECK Machine QA : Highly Efficient Quality Assurance Tool for VMAT, SRS & SBRT Linear Accelerator Delivery

    International Nuclear Information System (INIS)

    Mhatre, V; Patwe, P; Dandekar, P

    2016-01-01

    Purpose: Quality assurance (QA) of complex linear accelerators is critical and highly time consuming. ArcCHECK Machine QA tool is used to test geometric and delivery aspects of linear accelerator. In this study we evaluated the performance of this tool. Methods: Machine QA feature allows user to perform quality assurance tests using ArcCHECK phantom. Following tests were performed 1) Gantry Speed 2) Gantry Rotation 3) Gantry Angle 4)MLC/Collimator QA 5)Beam Profile Flatness & Symmetry. Data was collected on trueBEAM stX machine for 6 MV for a period of one year. The Gantry QA test allows to view errors in gantry angle, rotation & assess how accurately the gantry moves around the isocentre. The MLC/Collimator QA tool is used to analyze & locate the differences between leaf bank & jaw position of linac. The flatness & Symmetry test quantifies beam flatness & symmetry in IEC-y & x direction. The Gantry & Flatness/Symmetry test can be performed for static & dynamic delivery. Results: The Gantry speed was 3.9 deg/sec with speed maximum deviation around 0.3 deg/sec. The Gantry Isocentre for arc delivery was 0.9mm & static delivery was 0.4mm. The maximum percent positive & negative difference was found to be 1.9 % & – 0.25 % & maximum distance positive & negative diff was 0.4mm & – 0.3 mm for MLC/Collimator QA. The Flatness for Arc delivery was 1.8 % & Symmetry for Y was 0.8 % & X was 1.8 %. The Flatness for gantry 0°,270°,90° & 180° was 1.75,1.9,1.8 & 1.6% respectively & Symmetry for X & Y was 0.8,0.6% for 0°, 0.6,0.7% for 270°, 0.6,1% for 90° & 0.6,0.7% for 180°. Conclusion: ArcCHECK Machine QA is an useful tool for QA of Modern linear accelerators as it tests both geometric & delivery aspects. This is very important for VMAT, SRS & SBRT treatments.

  9. SU-E-T-226: Junction Free Craniospinal Irradiation in Linear Accelerator Using Volumetric Modulated Arc Therapy : A Novel Technique Using Dose Tapering

    International Nuclear Information System (INIS)

    Sarkar, B; Roy, S; Paul, S; Munshi, A; Roy, Shilpi; Jassal, K; Ganesh, T; Mohanti, BK

    2014-01-01

    Purpose: Spatially separated fields are required for craniospinal irradiation due to field size limitation in linear accelerator. Field junction shits are conventionally done to avoid hot or cold spots. Our study was aimed to demonstrate the feasibility of junction free irradiation plan of craniospinal irradiation (CSI) for Meduloblastoma cases treated in linear accelerator using Volumetric modulated arc therapy (VMAT) technique. Methods: VMAT was planned using multiple isocenters in Monaco V 3.3.0 and delivered in Elekta Synergy linear accelerator. A full arc brain and 40° posterior arc spine fields were planned using two isocentre for short (<1.3 meter height ) and 3 isocentres for taller patients. Unrestricted jaw movement was used in superior-inferior direction. Prescribed dose to PTV was achieved by partial contribution from adjacent beams. A very low dose gradient was generated to taper the isodoses over a long length (>10 cm) at the conventional field junction. Results: In this primary study five patients were planned and three patients were delivered using this novel technique. As the dose contribution from the adjacent beams were varied (gradient) to create a complete dose distribution, therefore there is no specific junction exists in the plan. The junction were extended from 10–14 cm depending on treatment plan. Dose gradient were 9.6±2.3% per cm for brain and 7.9±1.7 % per cm for spine field respectively. Dose delivery error due to positional inaccuracy was calculated for brain and spine field for ±1mm, ±2mm, ±3mm and ±5 mm were 1%–0.8%, 2%–1.6%, 2.8%–2.4% and 4.3%–4% respectively. Conclusion: Dose tapering in junction free CSI do not require a junction shift. Therefore daily imaging for all the field is also not essential. Due to inverse planning dose to organ at risk like thyroid kidney, heart and testis can be reduced significantly. VMAT gives a quicker delivery than Step and shoot or dynamic IMRT

  10. SU-F-T-459: ArcCHECK Machine QA : Highly Efficient Quality Assurance Tool for VMAT, SRS & SBRT Linear Accelerator Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Mhatre, V; Patwe, P; Dandekar, P [Sir HN RF Hospital, Mumbai, Maharashtra (India)

    2016-06-15

    Purpose: Quality assurance (QA) of complex linear accelerators is critical and highly time consuming. ArcCHECK Machine QA tool is used to test geometric and delivery aspects of linear accelerator. In this study we evaluated the performance of this tool. Methods: Machine QA feature allows user to perform quality assurance tests using ArcCHECK phantom. Following tests were performed 1) Gantry Speed 2) Gantry Rotation 3) Gantry Angle 4)MLC/Collimator QA 5)Beam Profile Flatness & Symmetry. Data was collected on trueBEAM stX machine for 6 MV for a period of one year. The Gantry QA test allows to view errors in gantry angle, rotation & assess how accurately the gantry moves around the isocentre. The MLC/Collimator QA tool is used to analyze & locate the differences between leaf bank & jaw position of linac. The flatness & Symmetry test quantifies beam flatness & symmetry in IEC-y & x direction. The Gantry & Flatness/Symmetry test can be performed for static & dynamic delivery. Results: The Gantry speed was 3.9 deg/sec with speed maximum deviation around 0.3 deg/sec. The Gantry Isocentre for arc delivery was 0.9mm & static delivery was 0.4mm. The maximum percent positive & negative difference was found to be 1.9 % & – 0.25 % & maximum distance positive & negative diff was 0.4mm & – 0.3 mm for MLC/Collimator QA. The Flatness for Arc delivery was 1.8 % & Symmetry for Y was 0.8 % & X was 1.8 %. The Flatness for gantry 0°,270°,90° & 180° was 1.75,1.9,1.8 & 1.6% respectively & Symmetry for X & Y was 0.8,0.6% for 0°, 0.6,0.7% for 270°, 0.6,1% for 90° & 0.6,0.7% for 180°. Conclusion: ArcCHECK Machine QA is an useful tool for QA of Modern linear accelerators as it tests both geometric & delivery aspects. This is very important for VMAT, SRS & SBRT treatments.

  11. Treatment accuracy of fractionated stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Kumar, Shaleen; Burke, Kevin; Nalder, Colin; Jarrett, Paula; Mubata, Cephas; A'Hern, Roger; Humphreys, Mandy; Bidmead, Margaret; Brada, Michael

    2005-01-01

    Background and purpose: To assess the geometric accuracy of the delivery of fractionated stereotactic radiotherapy (FSRT) for brain tumours using the Gill-Thomas-Cosman (GTC) relocatable frame. Accuracy of treatment delivery was measured via portal images acquired with an amorphous silicon based electronic portal imager (EPI). Results were used to assess the existing verification process and to review the current margins used for the expansion of clinical target volume (CTV) to planning target volume (PTV). Patients and methods: Patients were immobilized in a GTC frame. Target volume definition was performed on localization CT and MRI scans and a CTV to PTV margin of 5 mm (based on initial experience) was introduced in 3D. A Brown-Roberts-Wells (BRW) fiducial system was used for stereotactic coordinate definition. The existing verification process consisted of an intercomparison of the coordinates of the isocentres and anatomy between the localization and verification CT scans. Treatment was delivered with 6 MV photons using four fixed non-coplanar conformal fields using a multi-leaf collimator. Portal imaging verification consisted of the acquisition of orthogonal images centred through the treatment isocentre. Digitally reconstructed radiographs (DRRs) created from the CT localization scans were used as reference images. Semi-automated matching software was used to quantify set up deviations (displacements and rotations) between reference and portal images. Results: One hundred and twenty six anterior and 123 lateral portal images were available for analysis for set up deviations. For displacements, the total errors in the cranial/caudal direction were shown to have the largest SD's of 1.2 mm, while systematic and random errors reached SD's of 1.0 and 0.7 mm, respectively, in the cranial/caudal direction. The corresponding data for rotational errors (the largest deviation was found in the sagittal plane) was 0.7 deg. SD (total error), 0.5 deg. (systematic) and 0

  12. Sci-Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques - 02: Feasibility of using multileaf collimation for stereotactic radiosurgery of arteriovenous malformation

    International Nuclear Information System (INIS)

    Lee, Young; Ruschin, Mark; Tsao, May; Schwartz, Michael

    2016-01-01

    SRS using linac and cones offers steep dose fall-off but a tradeoff exists between conformality and treatment time, which depends on the number of isocentres. Purpose of this study is to quantify planning metrics between cones- and MLC-based SRS for arteriovenous malformation(AVM). Seven AVM cases treated with cones were re-planned with MLC on Pinnacle treatment planning system. Planning target volume(PTV) was created with 1mm uniform margin to the AVM to account for MLC positional variation. Clinically-planned prescription dose(15–25Gy) was used. Four plans were generated per case:non-coplanar VMAT(ncV), single-arc VMAT(saV), non-coplanar IMRT(ncI), non-coplanar conformal(ncC). Plans were compared for conformity(CI), heterogeneity(HI) and gradient(GI) indices and brain doses. Estimated treatment times and monitor units(MU) were compared. Cone-based plans required 2–6 isocentres. Though CI-RTOG was similar for plans(median=0.98), CI-Paddick was most favourable for ncV(median=0.86) and worst for cones(0.54). HI for MLC plans(median=1.19–1.27) were lower than cone-based plans(1.43). GI was similar for all plans. For 2/7 ncC had brainstem maximum dose>16.7Gy and therefore were clinically unacceptable. Brain V12Gy,V10Gy,V2Gy were lowest in the cones plan. ncV brain V12Gy,V10Gy,V2Gy were lowest of all MLC-based plans studied. Treatment MUs were similar for MLC-based plans and up to 70% lower than clinically delivered plans. ncV showed best conformality in this study. Of the MLC-based plans, ncV also showed lowest normal tissue dose with reasonable treatment time.

  13. Sci-Fri PM: Radiation Therapy, Planning, Imaging, and Special Techniques - 02: Feasibility of using multileaf collimation for stereotactic radiosurgery of arteriovenous malformation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young; Ruschin, Mark [Department of Medical Physics, Sunnybrook Health Science Centre, University of Toronto (Canada); Tsao, May [Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto (Canada); Schwartz, Michael [Department of Surgery (Neurosurgery), Sunnybrook Health Sciences Centre, University of Toronto (Canada)

    2016-08-15

    SRS using linac and cones offers steep dose fall-off but a tradeoff exists between conformality and treatment time, which depends on the number of isocentres. Purpose of this study is to quantify planning metrics between cones- and MLC-based SRS for arteriovenous malformation(AVM). Seven AVM cases treated with cones were re-planned with MLC on Pinnacle treatment planning system. Planning target volume(PTV) was created with 1mm uniform margin to the AVM to account for MLC positional variation. Clinically-planned prescription dose(15–25Gy) was used. Four plans were generated per case:non-coplanar VMAT(ncV), single-arc VMAT(saV), non-coplanar IMRT(ncI), non-coplanar conformal(ncC). Plans were compared for conformity(CI), heterogeneity(HI) and gradient(GI) indices and brain doses. Estimated treatment times and monitor units(MU) were compared. Cone-based plans required 2–6 isocentres. Though CI-RTOG was similar for plans(median=0.98), CI-Paddick was most favourable for ncV(median=0.86) and worst for cones(0.54). HI for MLC plans(median=1.19–1.27) were lower than cone-based plans(1.43). GI was similar for all plans. For 2/7 ncC had brainstem maximum dose>16.7Gy and therefore were clinically unacceptable. Brain V12Gy,V10Gy,V2Gy were lowest in the cones plan. ncV brain V12Gy,V10Gy,V2Gy were lowest of all MLC-based plans studied. Treatment MUs were similar for MLC-based plans and up to 70% lower than clinically delivered plans. ncV showed best conformality in this study. Of the MLC-based plans, ncV also showed lowest normal tissue dose with reasonable treatment time.

  14. The Integrated Tiger Series version 5.0

    International Nuclear Information System (INIS)

    Laub, Th.W.; Kensek, R.P.; Franke, B.C.; Lorence, L.J.; Crawford, M.J.; Quirk, Th.J.

    2005-01-01

    The Integrated Tiger Series (ITS) is a powerful and user-friendly software package permitting Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. The package contains programs to perform 1-, 2-, and 3-dimensional simulations. Improvements in the ITS code package since the release of version 3.0 include improved physics, multigroup and adjoint capabilities, Computer-Aided Design geometry tracking, parallel implementations of all ITS codes, and more automated sub-zoning capabilities. These improvements and others are described as current or planned development efforts. The ITS package is currently at version 5.0. (authors)

  15. Accelerating execution of the integrated TIGER series Monte Carlo radiation transport codes

    International Nuclear Information System (INIS)

    Smith, L.M.; Hochstedler, R.D.

    1997-01-01

    Execution of the integrated TIGER series (ITS) of coupled electron/photon Monte Carlo radiation transport codes has been accelerated by modifying the FORTRAN source code for more efficient computation. Each member code of ITS was benchmarked and profiled with a specific test case that directed the acceleration effort toward the most computationally intensive subroutines. Techniques for accelerating these subroutines included replacing linear search algorithms with binary versions, replacing the pseudo-random number generator, reducing program memory allocation, and proofing the input files for geometrical redundancies. All techniques produced identical or statistically similar results to the original code. Final benchmark timing of the accelerated code resulted in speed-up factors of 2.00 for TIGER (the one-dimensional slab geometry code), 1.74 for CYLTRAN (the two-dimensional cylindrical geometry code), and 1.90 for ACCEPT (the arbitrary three-dimensional geometry code)

  16. Boltzmann-Fokker-Planck calculations using standard discrete-ordinates codes

    International Nuclear Information System (INIS)

    Morel, J.E.

    1987-01-01

    The Boltzmann-Fokker-Planck (BFP) equation can be used to describe both neutral and charged-particle transport. Over the past several years, the author and several collaborators have developed methods for representing Fokker-Planck operators with standard multigroup-Legendre cross-section data. When these data are input to a standard S/sub n/ code such as ONETRAN, the code actually solves the Boltzmann-Fokker-Planck equation rather than the Boltzmann equation. This is achieved wihout any modification to the S/sub n/ codes. Because BFP calculations can be more demanding from a numerical viewpoint than standard neutronics calculations, we have found it useful to implement new quadrature methods ad convergence acceleration methods in the standard discrete-ordinates code, ONETRAN. We discuss our BFP cross-section representation techniques, our improved quadrature and acceleration techniques, and present results from BFP coupled electron-photon transport calculations performed with ONETRAN. 19 refs., 7 figs

  17. A comparison of experiment, CEPXS/ONETRAN, TIGERP, and TIGER net electron emission coefficients for various bremsstrahlung spectra

    International Nuclear Information System (INIS)

    Ballard, W.P.; Lorence, L.J. Jr.; Snowden, D.P.; Van Lint, V.A.J.; Beale, E.S.

    1987-01-01

    This work compares a carefully designed experiment to measure photoemission with the predictions of three different codes (CEPXS/ONETRAN, TIGERP, and TIGER) for the complex bremsstrahlung spectra typical of very intense pulsed power x-ray generators. The Monte Carlo codes TIGER and TIGERP can calculate the net photon-induced electron emission but accurate results may require that statistical error be minimized. CEPXS/ONETRAN is a new deterministic coupled electron/photon transport code that is faster than Monte Carlo and is not subject to statistical error. The comparison of net yields is a sensitive test of the relative accuracy and efficiency of these various codes. The authors find that all of the codes substantially agree with the experiments for the forward net yields. However, for reverse net yields from high-Z materials, the codes overpredict relative to measurements

  18. PCR nuclear composition at 1-20 PeV according to lateral distributions of all EAS and EAS accompanied high-energy-gamma rays and hadrons in EC at Tien-Shan level

    International Nuclear Information System (INIS)

    Nesterova, N.M.; Pavlyuchenko, V.P.; Chubenko, A.P.; Shaulov, S.B.

    2003-01-01

    The Tien-Shan array Adron data are presented on electron-photon component lateral distributions (age parameter S) of extensive air showers of cosmic rays. The data are given as a dependence on the electron size N e for all showers and for showers accompanied by high-energy gamma rays and hadrons in X-ray films. N e characterizes the energy of primary-cosmic-ray nuclei E 0 . Later events are generated by primary photons chiefly. That allows judging on the proton role with E 0 change. S distributions point to the considerable part of light nuclei, protons mainly, at the region above knee of the spectrum at N e > 10 6 up to N e = 5 x 10 6 (E 0 ∼ 10 PeV) at least [ru

  19. ZZ ENDLIB, Coupled Electron and Photon Transport Library in ENDL Format

    International Nuclear Information System (INIS)

    2002-01-01

    Description of program or function: The LLNL Evaluated Nuclear Data Library has existed since 1958 in a succession of forms and formats. The present form is as a machine-independent character file format and contains data for the evaluated atomic relaxation data library (EADL), the evaluated photon interaction data library (EPDL), and the evaluated electron interaction data library (EEDL). The purpose of these libraries is to furnish data for coupled electron-photon transport calculations. In order to perform coupled photon-electron transport calculations, all three libraries are required. The UCRL-ID-117796 report included in the documentation for this package provides information on the contents and formats for all three libraries, which are included in this package. All of these libraries span atomic numbers, Z, from 1 to 100. Additionally the electron and photon interaction libraries cover the incident particle energy range from 10 eV to 100 GeV

  20. Theory, simulation and experiments for precise deflection control of radiotherapy electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa, R.; Leiva, J.; Moncada, R.; Rojas, L.; Santibanez, M.; Valente, M.; Young, H. [Universidad de la Frontera, Centro de Fisica e Ingenieria en Medicina, Av. Francisco Salazar 1145, Casilla 54-D, Temuco (Chile); Velasquez, J. [Universidad de la Frontera, Departamento de Ciencias Fisicas, Av. Francisco Salazar 1145, Casilla 54-D, Temuco (Chile); Zelada, G. [Clinica Alemana de Santiago, Av. Vitacura 5951, 13132 Vitacura, Santiago (Chile); Astudillo, R., E-mail: rodolfo.figueroa@ufrontera.cl [Hospital Base de Valdivia, C. Simpson 850, XIV Region de los Rios, Valdivia (Chile)

    2017-10-15

    Conventional radiotherapy is mainly applied by linear accelerators. Although linear accelerators provide dual (electron/photon) radiation beam modalities, both of them are intrinsically produced by a megavoltage electron current. Modern radiotherapy treatment techniques are based on suitable devices inserted or attached to conventional linear accelerators. Thus, precise control of delivered beam becomes a main key issue. This work presents an integral description of electron beam deflection control as required for novel radiotherapy technique based on convergent photon beam production. Theoretical and Monte Carlo approaches were initially used for designing and optimizing devices components. Then, dedicated instrumentation was developed for experimental verification of electron beam deflection due to the designed magnets. Both Monte Carlo simulations and experimental results support the reliability of electrodynamics models used for predict megavoltage electron beam control. (Author)

  1. Development of a computer program to determine the pulse-height distribution in a gamma-ray detector from an arbitrary geometry source -feasibility study

    International Nuclear Information System (INIS)

    Currie, G.D.; Marshall, M.

    1989-03-01

    The feasibility of developing a computer program suitable for evaluating the pulse-height spectrum in a gamma-ray detector from a complex geometry source has been examined. A selection of relevant programs, Monte Carlo radiation transport codes, have been identified and their applicability to this study discussed. It is proposed that the computation be performed in two parts: the evaluation of the photon fluence at the detector using a photon transport code, and calculation of the pulse-height distribution from this spectrum using response functions determined with an electron-photon transport code. The two transport codes selected to perform this procedure are MCNP (Monte Carlo Neutron Photon code), and EGS4 (Electron Gamma Shower code). (Author)

  2. Study of Growth Kinetics in One Dimensional and Two Dimensional ZnO Nanostructures

    Science.gov (United States)

    Yin, Xin

    Because of the merits arising from the unique geometry, nanostructure materials have been an essential class of materials, which have shown great potentials in the fields of electronics, photonics, and biology. With various nanostructures being intensively investigated and successfully complemented into device applications, there has been one increasing demand to the investigation of the growth mechanism devoted to the controlled nanostructure synthesis. Motivated by this situation, this thesis is focused on the fundamental understanding of the nanostructure growth. Specifically, by taking zinc oxide as an example material, through controlling the basic driving force, that is, the supersaturation, I have rationally designed and synthesized various of nanostructures, and further applied the classical layer-by-layer growth mechanism to the understanding on the formation of these nanostructures, they are, the convex-plate-capped nanowires, the concave-plate-capped nanowires, the facet evolution at the tip of the nanowires, and the ultrathin 2D nanosheets.

  3. A 19-state R-matrix investigation of resonances in e--He scattering at low energies. Pt. 4

    International Nuclear Information System (INIS)

    Fon, W.C.; Lim, K.P.

    1993-01-01

    The authors have previously reported the 11-state and 19-state R-matrix calculations of 1 1 S-2 3,1 S and 1 1 S-2 3 P differential cross sections at low energies. In this paper, the same R-matrix calculations are extended to obtain the differential cross sections and the electron-photon coincidence parameters λ and |Χ| for the excitation of the ground state helium to the 2 1 P state. Convergence studies are carried out between the 11-state and 19-state R-matrix calculations. Only the 19-state R-matrix results are presented in full at scattering angles of 20 o , 30 o , 60 o , 90 o , 120 o and 140 o from the excitation threshold up to 23.8 eV. (author)

  4. Temporary acceleration of electrons while inside an intense electromagnetic pulse

    Directory of Open Access Journals (Sweden)

    Kirk T. McDonald

    1999-12-01

    Full Text Available A free electron can temporarily gain a very significant amount of energy if it is overrun by an intense electromagnetic wave. In principle, this process would permit large enhancements in the center-of-mass energy of electron-electron, electron-positron, and electron-photon interactions if these take place in the presence of an intense laser beam. Practical considerations severely limit the utility of this concept for contemporary lasers incident on relativistic electrons. A more accessible laboratory phenomenon is electron-positron production via an intense laser beam incident on a gas. Intense electromagnetic pulses of astrophysical origin can lead to very energetic photons via bremsstrahlung of temporarily accelerated electrons.

  5. MUSiC. A model unspecific search in CMS based on 2010 LHC data

    Energy Technology Data Exchange (ETDEWEB)

    Pieta, Holger

    2012-06-20

    A Model Unspecific Search in CMS (MUSiC) is presented in this work, along with its results on the data taken in 2010 by the Compact Muon Solenoid (CMS) at the Large Hadron Collider (LHC). This analysis shows a sensitivity to various models for new physics and provides a broad view at the data, due to its minimal theoretical bias. Events are classified with respect to their reconstructed objects: Muons, electrons, photons, jets and missing transverse energy. Up to three kinematic variables in each of these classes are systematically scanned for continuous bin regions deviating significantly from the predictions by the Standard Model of particle physics. No deviations beyond expected fluctuations are observed, when taking systematic uncertainties into account. The sensitivity of the analysis to certain models beyond the Standard Model is demonstrated.

  6. Phase Transitions of the Polariton Condensate in 2D Dirac Materials.

    Science.gov (United States)

    Lee, Ki Hoon; Lee, Changhee; Min, Hongki; Chung, Suk Bum

    2018-04-13

    For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon (e-ph) coupling can lead to the hybridizations of the exciton and the cavity photon known as polaritons, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped two-dimensional Dirac material such as the transition metal dichalcogenide MoS_{2} or WSe_{2}. Specifically, in forming the polariton, the e-ph coupling from the optical selection rule due to the Berry phase can compete against the Coulomb electron-electron (e-e) interaction. We find that this competition gives rise to a rich phase diagram for the polariton condensate involving both topological and symmetry breaking phase transitions, with the former giving rise to the quantum anomalous Hall and the quantum spin Hall phases.

  7. Phase Transitions of the Polariton Condensate in 2D Dirac Materials

    Science.gov (United States)

    Lee, Ki Hoon; Lee, Changhee; Min, Hongki; Chung, Suk Bum

    2018-04-01

    For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon (e -ph) coupling can lead to the hybridizations of the exciton and the cavity photon known as polaritons, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped two-dimensional Dirac material such as the transition metal dichalcogenide MoS2 or WSe2 . Specifically, in forming the polariton, the e -ph coupling from the optical selection rule due to the Berry phase can compete against the Coulomb electron-electron (e -e ) interaction. We find that this competition gives rise to a rich phase diagram for the polariton condensate involving both topological and symmetry breaking phase transitions, with the former giving rise to the quantum anomalous Hall and the quantum spin Hall phases.

  8. A general search for new phenomena at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania)]|[Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Inst., Moscow (RU)] (and others)

    2008-12-15

    A model-independent search for deviations from the Standard Model prediction is performed using the full e{sup {+-}}p data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis. (orig.)

  9. A general search for new phenomena in ep scattering at HERA

    International Nuclear Information System (INIS)

    Aktas, A.; Andreev, V.

    2004-08-01

    A model-independent search for deviations from the standard model prediction is performed in e + p and e - p collisions at HERA using H1 data corresponding to an integrated luminosity of 117 pb -1 . For the first time all event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A statistical algorithm is developed to search for deviations from the standard model in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles and to quantify their significance. A good agreement with the standard model prediction is observed in most of the event classes. The most significant deviation is found for a topology containing an isolated muon, missing transverse momentum and a jet, consistent with a previously reported observation. (orig.)

  10. A Model Independent General Search for new physics in ATLAS

    CERN Document Server

    Amoroso, S; The ATLAS collaboration

    2016-01-01

    We present results of a model-independent general search for new phenomena in proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. The data set corresponds to a total integrated luminosity of 20.3~\\ifb. Event topologies involving isolated electrons, photons and muons, as well as jets, including those identified as originating from \\textit{b}-quarks (\\textit{b}-jets) and missing transverse momentum are investigated. The events are subdivided according to their final states into exclusive event classes. For the 697 classes with a Standard Model expectation greater than 0.1 events, a search algorithm tests the compatibility of data against the Monte Carlo simulated background in three kinematic variables sensitive to new physics effects. No significant deviation is found in data. The number and size of the observed deviations follow the Standard Model expectation obtained from simulated pseudo-experiments.

  11. A General Search for New Phenomena at HERA

    CERN Document Server

    Aaron, F D; Andreev, V; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Behnke, O; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Hansson, M; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jonsson, L; Jung, Andreas Werner; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, Matthias Ulrich; Mudrinic, M; Muller, K; Murin, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, Ivan; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, Arnd E; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wessels, M; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F

    2009-01-01

    A model--independent search for deviations from the Standard Model prediction is performed using the full $e^\\pm p$ data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis.

  12. A Model Independent General Search for new physics in ATLAS

    Science.gov (United States)

    Amoroso, S.; ATLAS Collaboration

    2016-04-01

    We present results of a model-independent general search for new phenomena in proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. The data set corresponds to a total integrated luminosity of 20.3 fb-1. Event topologies involving isolated electrons, photons and muons, as well as jets, including those identified as originating from b-quarks (b-jets) and missing transverse momentum are investigated. The events are subdivided according to their final states into exclusive event classes. For the 697 classes with a Standard Model expectation greater than 0.1 events, a search algorithm tests the compatibility of data against the Monte Carlo simulated background in three kinematic variables sensitive to new physics effects. No significant deviation is found in data. The number and size of the observed deviations follow the Standard Model expectation obtained from simulated pseudo-experiments.

  13. General analysis of HERA II data

    International Nuclear Information System (INIS)

    Schoening, A

    2008-01-01

    A model-independent search for deviations from the Standard Model prediction is performed in e ± p collisions. Data collected in the years 2003-2007 corresponding to an integrated luminosity of about 340 pb -1 are analyzed. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A statistical algorithm is applied to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles and to quantify their significance. A good agreement with the Standard Model prediction is observed in most of the event classes. No significant deviation is observed in the phase-space and in the event topologies covered by this analysis

  14. A general search for new phenomena with the ATLAS detector at sqrt(s) = 8 TeV

    CERN Document Server

    Amoroso, S; The ATLAS collaboration

    2014-01-01

    We present a model-independent general search for new physics in proton proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. The data set, recorded by the ATLAS experiment during 2012, corresponds to a total integrated luminosity of 20.3~fb^{-1}. Event topologies involving isolated electrons, photons, muons, jets, b-jets and missing transverse momentum are investigated. The events are subdivided according to their final states into 713 exclusive analysis channels. For each channel, a search algorithm tests the compatibility of the effective mass distribution in data against the distribution in the Monte Carlo simulated background. Although this search approach is less sensitive than optimized searches for specific models it provides a more comprehensive investigation for new physics signals. No significant deviations between data and the Standard Model expectations have been observed.

  15. A general search for new phenomena in ep scattering at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kruger, K.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Paramonov, A.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2004-01-01

    A model-independent search for deviations from the Standard Model prediction is performed in e^+ p and e^- p collisions at HERA using H1 data corresponding to an integrated luminosity of 117 pb^-1. For the first time all event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A statistical algorithm is developed to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles and to quantify their significance. A good agreement with the Standard Model prediction is observed in most of the event classes. The most significant deviation is found for a topology containing an isolated muon, missing transverse momentum and a jet, consistent with a previously reported observation.

  16. A general search for new phenomena with the ATLAS detector in pp collisions at sort(s)=7 TeV.

    CERN Document Server

    The ATLAS collaboration

    2012-01-01

    This note presents a model-independent general search for new physics in proton proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector at the LHC. The data set, recorded by the ATLAS experiment during 2011, correspond to a total integrated luminosity of 4.7 fb-1. Event topologies involving isolated electrons, photons, muons, jets, b-jets and missing transverse momentum are investigated. The events are subdivided according to their final states into 655 exclusive analysis channels. For each channel, a search algorithm tests the compatibility of the effective mass distribution in data against the distribution in the Monte Carlo simulated background. Although this search approach is less sensitive than optimized searches for specific models it provides a more comprehensive in- vestigation for new physics signals. No significant deviations between data and the Standard Model expectations have been observed.

  17. Status of the Atlas Calorimeters: their performance during three years of LHC operation and plans for future upgrades.

    CERN Document Server

    Majewski, S; The ATLAS collaboration

    2014-01-01

    The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. Its calorimeter system measures the energy and direction of final state particles over the pseudorapidity range $|\\eta| < 4.9$. Accurate identification and measurement of the characteristics of electromagnetic objects (electrons/photons) are performed by liquid argon (LAr)-lead sampling calorimeters in the region $|\\eta| < 3.2$, using an innovative accordion geometry that provides a fast, uniform response without azimuthal gaps. This system played a critical role in the ATLAS analyses contributing to the Higgs boson discovery announced in 2012. The hadronic calorimeters measure the properties of hadrons, jets, and tau leptons, and also contribute to the measurement of the missing transverse energy and the identification of muons. A scintillator-steel sampling calorimeter (TileCal) is employed in the region $|\\eta| < 1.7$, while the region $1.5 < |\\eta| < 3.2$ is covered wi...

  18. Status of the Atlas Calorimeters: their performance after two years of LHC operation and plans for future upgrades

    CERN Document Server

    Solans, CA; The ATLAS collaboration

    2012-01-01

    The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. Its calorimeter system measures the energy and direction of final state particles with pseudo rapidity $|eta| < 4.9$. Accurate identification and measurement of the characteristics of electromagnetic objects (electrons/photons) are performed by liquid argon (LAr)-lead sampling calorimeters in the region $|eta| < 3.2$, using an innovative accordion geometry that provides a fast, uniform azimuthal response without gaps. The hadronic calorimeters measure the properties of hadrons, jets, and tau leptons, and also contribute to the measurement of the missing transverse energy and identification of muons. This is done in the region $|eta| < 1.7$ with a scintillator-steel sampling calorimeter, and in the region $1.4 < |eta| < 3.2$ with a copper-LAr sampling calorimeter. The coverage is extended to $|eta| < 4.9$ by an integrated forward calorimeter (FCal...

  19. The determination of electron momentum densities by inelastic scattering gamma-ray-electron coincidence measurements: The (γ,eγ)-experiment

    International Nuclear Information System (INIS)

    Rollason, A.J.; Bell, F.; Schneider, J.R.

    1989-09-01

    Measurements have been made of the recoiling electron in 320 keV gamma ray inelastic scattering collisions in thin aluminium targets. The angular correlation of these electrons detected in coincidence with the scattered photon is in agreement with the kinematic requirements of the Compton effect and is correctly predicted by Monte Carlo simulations based on the impulse approximation. Further simulations of ideal-geometry experiments indicate that information about the initial electron momenta is available from an examination of those electron-photon events originating in a surface layer of one electronic mean free path depth and that elastic scattering of the recoil electrons from greater depths produces a nearly flat background to this signal. The results clearly demonstrate the feasibility of the (γ,eγ) experiment for studying electron momentum densities with synchrotron radiation. (orig.) With 23 refs., 17 figs

  20. Solitons in one-dimensional charge density wave systems

    International Nuclear Information System (INIS)

    Su, W.P.

    1981-01-01

    Theoretical research on one dimensional charge density wave systems is outlined. A simple coupled electron-photon Hamiltonian is studied including a Green's function approach, molecular dynamics, and Monte Carlo path integral method. As in superconductivity, the nonperturbative nature of the system makes the physical ground states and low energy excitations drastically different from the bare electrons and phonons. Solitons carry quantum numbers which are entirely different from those of the bare electrons and holes. The fractional charge character of the solitons is an example of this fact. Solitons are conveniently generated by doping material with donors or acceptors or by photon absorption. Most predictions of the theory are in qualitative agreement with experiments. The one dimensional charge density wave system has potential technological importance and a possible role in uncovering phenomena which might have implications in relativistic field theory and elementary particle physics