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Sample records for proton density-weighted images

  1. Segmentation of humeral head from axial proton density weighted shoulder MR images

    NASA Astrophysics Data System (ADS)

    Sezer, Aysun; Sezer, Hasan Basri; Albayrak, Songul

    2015-01-01

    The purpose of this study is to determine the effectiveness of segmentation of axial MR proton density (PD) images of bony humeral head. PD sequence images which are included in standard shoulder MRI protocol are used instead of T1 MR images. Bony structures were reported to be successfully segmented in the literature from T1 MR images. T1 MR images give more sharp determination of bone and soft tissue border but cannot address the pathological process which takes place in the bone. In the clinical settings PD images of shoulder are used to investigate soft tissue alterations which can cause shoulder instability and are better in demonstrating edema and the pathology but have a higher noise ratio than other modalities. Moreover the alteration of humeral head intensity in patients and soft tissues in contact with the humeral head which have the very similar intensities with bone makes the humeral head segmentation a challenging problem in PD images. However segmentation of the bony humeral head is required initially to facilitate the segmentation of the soft tissues of shoulder. In this study shoulder MRI of 33 randomly selected patients were included. Speckle reducing anisotropic diffusion (SRAD) method was used to decrease noise and then Active Contour Without Edge (ACWE) and Signed Pressure Force (SPF) models were applied on our data set. Success of these methods is determined by comparing our results with manually segmented images by an expert. Applications of these methods on PD images provide highly successful results for segmentation of bony humeral head. This is the first study to determine bone contours in PD images in literature.

  2. Accuracy for detection of simulated lesions: comparison of fluid-attenuated inversion-recovery, proton density--weighted, and T2-weighted synthetic brain MR imaging

    NASA Technical Reports Server (NTRS)

    Herskovits, E. H.; Itoh, R.; Melhem, E. R.

    2001-01-01

    OBJECTIVE: The objective of our study was to determine the effects of MR sequence (fluid-attenuated inversion-recovery [FLAIR], proton density--weighted, and T2-weighted) and of lesion location on sensitivity and specificity of lesion detection. MATERIALS AND METHODS: We generated FLAIR, proton density-weighted, and T2-weighted brain images with 3-mm lesions using published parameters for acute multiple sclerosis plaques. Each image contained from zero to five lesions that were distributed among cortical-subcortical, periventricular, and deep white matter regions; on either side; and anterior or posterior in position. We presented images of 540 lesions, distributed among 2592 image regions, to six neuroradiologists. We constructed a contingency table for image regions with lesions and another for image regions without lesions (normal). Each table included the following: the reviewer's number (1--6); the MR sequence; the side, position, and region of the lesion; and the reviewer's response (lesion present or absent [normal]). We performed chi-square and log-linear analyses. RESULTS: The FLAIR sequence yielded the highest true-positive rates (p < 0.001) and the highest true-negative rates (p < 0.001). Regions also differed in reviewers' true-positive rates (p < 0.001) and true-negative rates (p = 0.002). The true-positive rate model generated by log-linear analysis contained an additional sequence-location interaction. The true-negative rate model generated by log-linear analysis confirmed these associations, but no higher order interactions were added. CONCLUSION: We developed software with which we can generate brain images of a wide range of pulse sequences and that allows us to specify the location, size, shape, and intrinsic characteristics of simulated lesions. We found that the use of FLAIR sequences increases detection accuracy for cortical-subcortical and periventricular lesions over that associated with proton density- and T2-weighted sequences.

  3. MRI of the normal brain from early childhood to middle age. I. Appearances on T2- and proton density-weighted images and occurrence of incidental high-signal foci.

    PubMed

    Autti, T; Raininko, R; Vanhanen, S L; Kallio, M; Santavuori, P

    1994-11-01

    The magnetic resonance images of 67 healthy subjects aged 4-50 years were studied for differences in general signal intensity between the different brain structures, the frequency of focal intensity changes in the brain, and variations in size of the cerebrospinal fluid (CSF) spaces. In adults over 25 years of age the thalamus gave lower signal than the putamen or caudate nucleus. Definite periventricular high signal was found in the white matter of one third of subjects of all ages. Small (< 5 mm in diameter) high signal foci were found in the cerebral white matter on T2-weighted images in 27% of subjects (20% of healthy children and adolescents and 34% of adults). They gave high signal on both short and long echoes in 11% of children and adolescents and in 22% of adults; 51% of all foci gave high signal with both echoes. This does not support the hypothesis that they are caused mainly by enlarged Virchow-Robin spaces. Of the high signal foci on T2-weighted images, 86% were in watershead areas. Two foci were found in one subject in the periventricular watershed area (beside the tips of the frontal horns) and they were never seen in the other deep white matter regions. In healthy, relatively young subjects with no known risk factors, high signal foci other than Virchow-Robin spaces, were common; neither their prevalence nor their number correlated with age in this series. A few slightly large sulci were found in some adults. PMID:7862287

  4. A geometric flow for segmenting vasculature in proton-density weighted MRI.

    PubMed

    Descoteaux, Maxime; Collins, D Louis; Siddiqi, Kaleem

    2008-08-01

    Modern neurosurgery takes advantage of magnetic resonance images (MRI) of a patient's cerebral anatomy and vasculature for planning before surgery and guidance during the procedure. Dual echo acquisitions are often performed that yield proton-density (PD) and T2-weighted images to evaluate edema near a tumor or lesion. In this paper we develop a novel geometric flow for segmenting vasculature in PD images, which can also be applied to the easier cases of MR angiography data or Gadolinium enhanced MRI. Obtaining vasculature from PD data is of clinical interest since the acquisition of such images is widespread, the scanning process is non-invasive, and the availability of vessel segmentation methods could obviate the need for an additional angiographic or contrast-based sequence during preoperative imaging. The key idea is to first apply Frangi's vesselness measure [Frangi, A., Niessen, W., Vincken, K.L., Viergever, M.A., 1998. Multiscale vessel enhancement filtering. In: International Conference on Medical Image Computing and Computer Assisted Intervention, vol. 1496 of Lecture Notes in Computer Science, pp. 130-137] to find putative centerlines of tubular structures along with their estimated radii. This measure is then distributed to create a vector field which allows the flux maximizing flow algorithm of Vasilevskiy and Siddiqi [Vasilevskiy, A., Siddiqi, K., 2002. Flux maximizing geometric flows. IEEE Transactions on Pattern Analysis and Machine Intelligence 24 (12), 1565-1578] to be applied to recover vessel boundaries. We carry out a qualitative validation of the approach on PD, MR angiography and Gadolinium enhanced MRI volumes and suggest a new way to visualize the segmentations in 2D with masked projections. We validate the approach quantitatively on a single-subject data set consisting of PD, phase contrast (PC) angiography and time of flight (TOF) angiography volumes, with an expert segmented version of the TOF volume viewed as the ground truth. We then validate the approach quantitatively on 19 PD data sets from a new digital brain phantom, with semi-automatically obtained labels from the corresponding angiography volumes viewed as ground truth. A significant finding is that both for the single-subject and multi-subject studies, 90% or more of the vasculature in the ground truth segmentation is recovered from the automatic segmentation of the other volumes. PMID:18375175

  5. [Proton imaging applications for proton therapy: state of the art].

    PubMed

    Amblard, R; Floquet, V; Angellier, G; Hannoun-Lvi, J M; Hrault, J

    2015-04-01

    Proton therapy allows a highly precise tumour volume irradiation with a low dose delivered to the healthy tissues. The steep dose gradients observed and the high treatment conformity require a precise knowledge of the proton range in matter and the target volume position relative to the beam. Thus, proton imaging allows an improvement of the treatment accuracy, and thereby, in treatment quality. Initially suggested in 1963, radiographic imaging with proton is still not used in clinical routine. The principal difficulty is the lack of spatial resolution, induced by the multiple Coulomb scattering of protons with nuclei. Moreover, its realization for all clinical locations requires relatively high energies that are previously not considered for clinical routine. Abandoned for some time in favor of X-ray technologies, research into new imaging methods using protons is back in the news because of the increase of proton radiation therapy centers in the world. This article exhibits a non-exhaustive state of the art in proton imaging. PMID:25640216

  6. Proton Therapy Verification with PET Imaging

    PubMed Central

    Zhu, Xuping; Fakhri, Georges El

    2013-01-01

    Proton therapy is very sensitive to uncertainties introduced during treatment planning and dose delivery. PET imaging of proton induced positron emitter distributions is the only practical approach for in vivo, in situ verification of proton therapy. This article reviews the current status of proton therapy verification with PET imaging. The different data detecting systems (in-beam, in-room and off-line PET), calculation methods for the prediction of proton induced PET activity distributions, and approaches for data evaluation are discussed. PMID:24312147

  7. Calibration of the LLNL Imaging Proton Spectrometer

    NASA Astrophysics Data System (ADS)

    Rasmus, A. M.; Manuel, M. J.-E.; Kuranz, C. C.; Klein, S.; Belancourt, P. X.; Fein, J. R.; MacDonald, M. J.; Drake, R. P.; Hazi, A. U.; Pollock, B. B.; Park, J.; Williams, G. J.; Chen, H.

    2014-10-01

    Ultra intense short pulse lasers incident on solid targets (e.g. Au foil) produce well collimated, broadband proton beams. These proton beams can be used to characterize magnetic fields in high-energy-density systems. The Imaging Proton Spectrometer (IPS) was previously designed and built (H. Chen 2010, RSI) for use with such laser produced proton beams. The IPS has an energy range of 50 keV-40 MeV with a resolving power (E/dE) of about 250 at 0.5 MeV and 350 at 2 MeV, as well as a single spatial imaging direction. In order to better characterize the imaging capability of this diagnostic, a 3D FEA solver has been used to calculate the magnetic field of the IPS. Particle trajectories are then obtained via numerical integration to calibrate the imaging axis of the IPS. Experiments using alpha sources will be used to verify the calculated calibration. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, Grant Number DE-NA0001840. Work by LLNL was performed under the auspices of U.S. DOE under Contract DE-AC52-07NA27344.

  8. Advanced proton imaging in computed tomography.

    PubMed

    Mattiazzo, S; Bisello, D; Giubilato, P; Pantano, D; Pozzobon, N; Snoeys, W; Wyss, J

    2015-09-01

    In recent years the use of hadrons for cancer radiation treatment has grown in importance, and many facilities are currently operational or under construction worldwide. To fully exploit the therapeutic advantages offered by hadron therapy, precise body imaging for accurate beam delivery is decisive. Proton computed tomography (pCT) scanners, currently in their R&D phase, provide the ultimate 3D imaging for hadrons treatment guidance. A key component of a pCT scanner is the detector used to track the protons, which has great impact on the scanner performances and ultimately limits its maximum speed. In this article, a novel proton-tracking detector was presented that would have higher scanning speed, better spatial resolution and lower material budget with respect to present state-of-the-art detectors, leading to enhanced performances. This advancement in performances is achieved by employing the very latest development in monolithic active pixel detectors (to build high granularity, low material budget, large area silicon detectors) and a completely new proprietary architecture (to effectively compress the data). PMID:25911407

  9. Techniques in Iterative Proton CT Image Reconstruction

    NASA Astrophysics Data System (ADS)

    Penfold, Scott; Censor, Yair

    2015-11-01

    This is a review paper on some of the physics, modeling, and iterative algorithms in proton computed tomography (pCT) image reconstruction. The primary challenge in pCT image reconstruction lies in the degraded spatial resolution resulting from multiple Coulomb scattering within the imaged object. Analytical models such as the most likely path have been proposed to predict the scattered trajectory from measurements of individual proton location and direction before and after the object. Iterative algorithms provide a flexible tool with which to incorporate these models into image reconstruction. The modeling leads to a large and sparse linear system of equations that can efficiently be solved by projection methods-based iterative algorithms. Such algorithms perform projections of the iterates onto the hyperlanes that are represented by the linear equations of the system. They perform these projections in possibly various algorithmic structures, such as block-iterative projections, string-averaging projections. These algorithmic schemes allow flexibility of choosing blocks, strings, and other parameters. They also cater for parallel implementations which are apt to further save clock time in computations. Experimental results are presented which compare some of those algorithmic options.

  10. Ultrafast laser-driven proton sources and dynamic proton imaging

    SciTech Connect

    Nickles, Peter V.; Schnuerer, Matthias; Sokollik, Thomas; Ter-Avetisyan, Sargis; Sandner, Wolfgang; Amin, Munib; Toncian, Toma; Willi, Oswald; Andreev, Alexander

    2008-07-15

    Ion bursts, accelerated by an ultrafast (40 fs) laser-assisted target normal sheath acceleration mechanism, can be adjusted so as to deliver a nearly pure proton beam. Such laser-driven proton bursts have predominantly a low transverse emittance and a broad kinetic spectrum suitable for continuous probing of the temporal evolution of spatially extended electric fields that arise after laser irradiation of thin foils. Fields with a strength of up to 10{sup 10} V/m were measured with a new streaklike proton deflectometry setup. The data show the temporal and spatial evolution of electric fields that are due to target charge-up and ion-front expansion following intense laser-target interaction at intensities of 10{sup 17}-10{sup 18} W/cm{sup 2}. Measurement of the field evolution is important to gain further insight into lateral electron-transport processes and the influence of field dynamics on ion beam properties.

  11. Modeling and optimization of a time-resolved proton radiographic imaging system for proton cancer treatment

    NASA Astrophysics Data System (ADS)

    Han, Bin

    This dissertation describes a research project to test the clinical utility of a time-resolved proton radiographic (TRPR) imaging system by performing comprehensive Monte Carlo simulations of a physical device coupled with realistic lung cancer patient anatomy defined by 4DCT for proton therapy. A time-resolved proton radiographic imaging system was modeled through Monte Carlo simulations. A particle-tracking feature was employed to evaluate the performance of the proton imaging system, especially in its ability to visualize and quantify proton range variations during respiration. The Most Likely Path (MLP) algorithm was developed to approximate the multiple Coulomb scattering paths of protons for the purpose of image reconstruction. Spatial resolution of 1 mm and range resolution of 1.3% of the total range were achieved using the MLP algorithm. Time-resolved proton radiographs of five patient cases were reconstructed to track tumor motion and to calculate water equivalent length variations. By comparing with direct 4DCT measurement, the accuracy of tumor tracking was found to be better than 2 mm in five patient cases. Utilizing tumor tracking information to reduce margins to the planning target volume, a gated treatment plan was compared with un-gated treatment plan. The equivalent uniform dose (EUD) and the normal tissue complication probability (NTCP) were used to quantify the gain in the quality of treatments. The EUD of the OARs was found to be reduced up to 11% and the corresponding NTCP of organs at risk (OARs) was found to be reduced up to 16.5%. These results suggest that, with image guidance by proton radiography, dose to OARs can be reduced and the corresponding NTCPs can be significantly reduced. The study concludes that the proton imaging system can accurately track the motion of the tumor and detect the WEL variations, leading to potential gains in using image-guided proton radiography for lung cancer treatments.

  12. Proton dose calculation on scatter-corrected CBCT image: Feasibility study for adaptive proton therapy

    PubMed Central

    Park, Yang-Kyun; Sharp, Gregory C.; Phillips, Justin; Winey, Brian A.

    2015-01-01

    Purpose: To demonstrate the feasibility of proton dose calculation on scatter-corrected cone-beam computed tomographic (CBCT) images for the purpose of adaptive proton therapy. Methods: CBCT projection images were acquired from anthropomorphic phantoms and a prostate patient using an on-board imaging system of an Elekta infinity linear accelerator. Two previously introduced techniques were used to correct the scattered x-rays in the raw projection images: uniform scatter correction (CBCTus) and a priori CT-based scatter correction (CBCTap). CBCT images were reconstructed using a standard FDK algorithm and GPU-based reconstruction toolkit. Soft tissue ROI-based HU shifting was used to improve HU accuracy of the uncorrected CBCT images and CBCTus, while no HU change was applied to the CBCTap. The degree of equivalence of the corrected CBCT images with respect to the reference CT image (CTref) was evaluated by using angular profiles of water equivalent path length (WEPL) and passively scattered proton treatment plans. The CBCTap was further evaluated in more realistic scenarios such as rectal filling and weight loss to assess the effect of mismatched prior information on the corrected images. Results: The uncorrected CBCT and CBCTus images demonstrated substantial WEPL discrepancies (7.3 ± 5.3 mm and 11.1 ± 6.6 mm, respectively) with respect to the CTref, while the CBCTap images showed substantially reduced WEPL errors (2.4 ± 2.0 mm). Similarly, the CBCTap-based treatment plans demonstrated a high pass rate (96.0% ± 2.5% in 2 mm/2% criteria) in a 3D gamma analysis. Conclusions: A priori CT-based scatter correction technique was shown to be promising for adaptive proton therapy, as it achieved equivalent proton dose distributions and water equivalent path lengths compared to those of a reference CT in a selection of anthropomorphic phantoms. PMID:26233175

  13. Proton tracking for medical imaging and dosimetry

    NASA Astrophysics Data System (ADS)

    Taylor, J. T.; Allport, P. P.; Casse, G. L.; Smith, N. A.; Tsurin, I.; Allinson, N. M.; Esposito, M.; Kacperek, A.; Nieto-Camero, J.; Price, T.; Waltham, C.

    2015-02-01

    For many years, silicon micro-strip detectors have been successfully used as tracking detectors for particle and nuclear physics experiments. A new application of this technology is to the field of particle therapy, where radiotherapy is carried out by use of charged particles such as protons or carbon ions. Such a treatment has been shown to have advantages over standard x-ray radiotherapy and as a result of this, many new centres offering particle therapy are currently under constructionincluding two in the U.K.. The characteristics of a new silicon micro-strip detector based system for this application will be presented. The array uses specifically designed large area sensors in several stations in an x-u-v co-ordinate configuration suitable for very fast proton tracking with minimal ambiguities. The sensors will form a tracker capable of giving information on the path of high energy protons entering and exiting a patient. This will allow proton computed tomography (pCT) to aid the accurate delivery of treatment dose with tuned beam profile and energy. The tracker will also be capable of proton counting and position measurement at the higher fluences and full range of energies used during treatment allowing monitoring of the beam profile and total dose. Results and initial characterisation of sensors will be presented along with details of the proposed readout electronics. Radiation tests and studies with different electronics at the Clatterbridge Cancer Centre and the higher energy proton therapy facility of iThemba LABS in South Africa will also be shown.

  14. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition

  15. Density Weighted FDF Equations for Simulations of Turbulent Reacting Flows

    NASA Technical Reports Server (NTRS)

    Shih, Tsan-Hsing; Liu, Nan-Suey

    2011-01-01

    In this report, we briefly revisit the formulation of density weighted filtered density function (DW-FDF) for large eddy simulation (LES) of turbulent reacting flows, which was proposed by Jaberi et al. (Jaberi, F.A., Colucci, P.J., James, S., Givi, P. and Pope, S.B., Filtered mass density function for Large-eddy simulation of turbulent reacting flows, J. Fluid Mech., vol. 401, pp. 85-121, 1999). At first, we proceed the traditional derivation of the DW-FDF equations by using the fine grained probability density function (FG-PDF), then we explore another way of constructing the DW-FDF equations by starting directly from the compressible Navier-Stokes equations. We observe that the terms which are unclosed in the traditional DW-FDF equations are now closed in the newly constructed DW-FDF equations. This significant difference and its practical impact on the computational simulations may deserve further studies.

  16. Improved proton computed tomography by dual modality image reconstruction

    SciTech Connect

    Hansen, David C. Bassler, Niels; Petersen, Jørgen Breede Baltzer; Sørensen, Thomas Sangild

    2014-03-15

    Purpose: Proton computed tomography (CT) is a promising image modality for improving the stopping power estimates and dose calculations for particle therapy. However, the finite range of about 33 cm of water of most commercial proton therapy systems limits the sites that can be scanned from a full 360° rotation. In this paper the authors propose a method to overcome the problem using a dual modality reconstruction (DMR) combining the proton data with a cone-beam x-ray prior. Methods: A Catphan 600 phantom was scanned using a cone beam x-ray CT scanner. A digital replica of the phantom was created in the Monte Carlo code Geant4 and a 360° proton CT scan was simulated, storing the entrance and exit position and momentum vector of every proton. Proton CT images were reconstructed using a varying number of angles from the scan. The proton CT images were reconstructed using a constrained nonlinear conjugate gradient algorithm, minimizing total variation and the x-ray CT prior while remaining consistent with the proton projection data. The proton histories were reconstructed along curved cubic-spline paths. Results: The spatial resolution of the cone beam CT prior was retained for the fully sampled case and the 90° interval case, with the MTF = 0.5 (modulation transfer function) ranging from 5.22 to 5.65 linepairs/cm. In the 45° interval case, the MTF = 0.5 dropped to 3.91 linepairs/cm For the fully sampled DMR, the maximal root mean square (RMS) error was 0.006 in units of relative stopping power. For the limited angle cases the maximal RMS error was 0.18, an almost five-fold improvement over the cone beam CT estimate. Conclusions: Dual modality reconstruction yields the high spatial resolution of cone beam x-ray CT while maintaining the improved stopping power estimation of proton CT. In the case of limited angles, the use of prior image proton CT greatly improves the resolution and stopping power estimate, but does not fully achieve the quality of a 360° proton CT scan.

  17. Proton-induced x-ray fluorescence CT imaging

    PubMed Central

    Bazalova-Carter, Magdalena; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Matsuo, Yuto; Fahrig, Rebecca; Shirato, Hiroki; Umegaki, Kikuo; Xing, Lei

    2015-01-01

    Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 3 mm2 CdTe detector placed at 90 with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10 were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R2 > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%5% gold solutions in a small animal sized water phantom has been demonstrated for the first time by means of experiments and MC simulations. PMID:25652502

  18. Proton-induced x-ray fluorescence CT imaging

    SciTech Connect

    Bazalova-Carter, Magdalena Xing, Lei; Ahmad, Moiz; Matsuura, Taeko; Takao, Seishin; Shirato, Hiroki; Umegaki, Kikuo; Matsuo, Yuto; Fahrig, Rebecca

    2015-02-15

    Purpose: To demonstrate the feasibility of proton-induced x-ray fluorescence CT (pXFCT) imaging of gold in a small animal sized object by means of experiments and Monte Carlo (MC) simulations. Methods: First, proton-induced gold x-ray fluorescence (pXRF) was measured as a function of gold concentration. Vials of 2.2 cm in diameter filled with 0%–5% Au solutions were irradiated with a 220 MeV proton beam and x-ray fluorescence induced by the interaction of protons, and Au was detected with a 3 × 3 mm{sup 2} CdTe detector placed at 90° with respect to the incident proton beam at a distance of 45 cm from the vials. Second, a 7-cm diameter water phantom containing three 2.2-diameter vials with 3%–5% Au solutions was imaged with a 7-mm FWHM 220 MeV proton beam in a first generation CT scanning geometry. X-rays scattered perpendicular to the incident proton beam were acquired with the CdTe detector placed at 45 cm from the phantom positioned on a translation/rotation stage. Twenty one translational steps spaced by 3 mm at each of 36 projection angles spaced by 10° were acquired, and pXFCT images of the phantom were reconstructed with filtered back projection. A simplified geometry of the experimental data acquisition setup was modeled with the MC TOPAS code, and simulation results were compared to the experimental data. Results: A linear relationship between gold pXRF and gold concentration was observed in both experimental and MC simulation data (R{sup 2} > 0.99). All Au vials were apparent in the experimental and simulated pXFCT images. Specifically, the 3% Au vial was detectable in the experimental [contrast-to-noise ratio (CNR) = 5.8] and simulated (CNR = 11.5) pXFCT image. Due to fluorescence x-ray attenuation in the higher concentration vials, the 4% and 5% Au contrast were underestimated by 10% and 15%, respectively, in both the experimental and simulated pXFCT images. Conclusions: Proton-induced x-ray fluorescence CT imaging of 3%–5% gold solutions in a small animal sized water phantom has been demonstrated for the first time by means of experiments and MC simulations.

  19. Imaging of Plasma Focus Fusion by Proton Coded Aperture Technique

    NASA Astrophysics Data System (ADS)

    Talebitaher, Alireza; Springham, Stuart Victor; Shutler, Paul Maurice Edmund; Lee, Paul; Rawat, Rajdeep Singh

    2012-06-01

    The coded aperture imaging (CAI) technique has been applied to investigate the spatial distribution of DD fusion in a deuterium filled 1.6 kJ plasma focus (PF) device operated in its neutron-optimized regime. The coded mask has been fabricated in Havar alloy with 20 20 pixels and 57 square holes (14% open area) using a Singer-set Cyclic Difference pattern. Five CAI cameras were employed simultaneously: one placed on-axis (0) and four at 45 to the PF axis. CR-39 polymer nuclear track detectors were used to register proton tracks from D(d,p)T reactions. The detectors were covered by 75 ?m Kapton film to stop all energetic charged particles (mostly deuterons) other than the 3 MeV fusion protons. A de-convolution algorithm was applied to the measured proton track coordinates to obtain images of the fusion source from the five directions. Typically (2-8) 104 proton tracks were registered by each detector per shot. Also two beryllium fast-neutron detectors were employed simultaneously to measure the associated neutron yield and anisotropy. The CAI images show the fusion source is a cigar-shaped region around the pinch column with no indication of plasma column instabilities. The proton anisotropy is comparable to the measured neutron anisotropy.

  20. A proton imaging device: Design and status of realization

    NASA Astrophysics Data System (ADS)

    Sipala, V.; Bruzzi, M.; Bucciolini, M.; Candiano, G.; Capineri, L.; P. Cirrone, G. A.; Civinini, C.; Cuttone, G.; Lo Presti, D.; Marrazzo, L.; Mazzaglia, E.; Menichelli, D.; Randazzo, N.; Talamonti, C.; Valentini, S.

    2010-01-01

    Proton radiation therapy is a precise form of cancer therapy, which requires verification of the patient position and the accurate knowledge of the dose delivered to the patient. At present in the proton treatment centre, patients are positioned with X-ray radiography and dose calculations rely on the patient's morphology and electron densities obtained by X-ray computed tomography [U. Schneider, E. Pedroni, Med. Phys. 22 (1995) 353]. A proton imaging device can improve the accuracy of proton radiation therapy treatment planning and the alignment of the patient with the proton beam. Our collaboration has developed a pCR prototype consisting of a silicon microstrip tracker and a calorimeter to detect the residual energy [R. Shulte, et al., IEEE Trans. Nucl. Sci. 51 (2004) 866-872]. In this contribution we will show some results obtained testing the front-end board of the tracker and measurements performed at LNS (Laboratori Nazionali del Sud) and in LLUMC (Loma Linda University Medical Centre) using 60 and 200 MeV proton beams to test the calorimeter.

  1. The Italian project for a proton imaging device

    NASA Astrophysics Data System (ADS)

    Cirrone, G. A. P.; Candiano, G.; Cuttone, G.; Lo Nigro, S.; Lo Presti, D.; Randazzo, N.; Sipala, V.; Russo, M.; Aiello, S.; Bruzzi, M.; Menichelli, D.; Scaringella, M.; Miglio, S.; Bucciolini, M.; Talamonti, C.; Pallotta, S.

    2007-06-01

    Proton Computed Tomography (or pCT) is a new imaging technique based on the use of high energy proton beams (200-250 MeV) replacing of the commonly adopted X-rays CT. pCT that was firstly proposed in the 1960s but only nowadays, with the continued establishing of new proton therapy centers around the world, the interest in it is growing. The use of protons for tomographic images can represent, in fact, a big enhancement in the quality of a proton therapy treatment either in the patient positioning as well as in the accuracy of the dose calculation for the treatment planning phase. In this paper, after a brief introduction on pCT principles, the main hardware and software characteristics of a first pCT prototype in development by our group (the Italian PRIMA collaboration) will be presented. The role of Monte Carlo simulation in developing will be also emphasized, using the GEANT4 simulation toolkit.

  2. Observation of dayside subauroral proton flashes with IMAGE-FUV.

    NASA Astrophysics Data System (ADS)

    Hubert, B.; Grard, J.-C.; Fuselier, S. A.; Mende, S. B.

    2003-04-01

    The IMAGE-FUV experiment onboard the IMAGE satellite includes three imagers: the WIC and SI13 instruments produce a global scale imaging of the N_2 LBH wavelength range and of the OI 130.4 nm emission respectively, and are thus devoted to the study of the electron aurora. The third imager, SI12, remotely senses the Doppler shifted Lyman-alpha emission, that is solely due to the proton aurora, at the global scale. We present here a new auroral feature observed with the SI12 instrument, consisting of sudden dayside subauroral injections of protons at magnetic latitudes sometimes lower than 60^o MLAT, at the foot of field lines of L shells as low as 4 RE. The extension of the feature in magnetic local time is variable and cases extending from 0700 to 1500 MLT were seen. The relaxation time of these features will be discussed. Most of these dayside subauroral proton flashes are found to be related to sudden solar wind dynamic pressure pulses, but a few counter examples were found. The relationship with the IMF orientation is investigated.

  3. Electron and proton shock aurora observed by IMAGE-FUV

    NASA Astrophysics Data System (ADS)

    Meurant, M.; Grard, J. C.; Hubert, B.; Coumans, V.; Blockx, C.

    2003-04-01

    The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) satellite monitors the aurora in three different spectral regions. The Wideband Imaging Camera (WIC) observes the molecular N_2 LBH and the atomic NI emissions at 140-180 nm. The two channels of the Spectrographic Imager (SI) observe the Doppler shifted Lyman-? emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). Three simultaneous snapshots are recorded each 2 minutes. In this study, the FUV instrument allows a global viewing of the aurora with a high temporal resolution both in proton and electron. It is used to study the shock aurora resulting from the disturbance caused by the arrival of a coronal mass ejection on the front of the magnetosphere. A comparison between electron and proton injection features at global scale is performed for different isolated events with positive and negative interplanetary B_z. A correlation with IMF and solar wind parameters is presented as well as a description of the magnetosphere morphology given by the Tsyganenko model in the shock aurora period.

  4. An adaptive density-weighted contrast enhancement filter for mammographic breast mass detection

    SciTech Connect

    Petrick, N.; Chan, H.P.; Sahiner, B.; Wei, D.

    1996-02-01

    This paper presents a novel approach for segmentation of suspicious mass regions in digitized mammograms using a new adaptive density-weighted contrast enhancement (DWCE) filter in conjunction with Laplacian-Gaussian (LG) edge detection. The DWCE enhances structures within the digitized mammogram so that a simple edge detection algorithm can be used to define the boundaries of the objectives. Once the object boundaries are known, morphological features are extracted and used by a classification algorithm to differentiate regions within the image. This paper introduces the DWCE algorithm and presents results of a preliminary study based on 25 digitized mammograms with biopsy proven masses. It also compares morphological feature classification based on sequential thresholding, linear discriminant analysis, and neural network classifiers for reduction of false-positive detections.

  5. Method and apparatus for imaging through 3-dimensional tracking of protons

    NASA Technical Reports Server (NTRS)

    Ryan, James M. (Inventor); Macri, John R. (Inventor); McConnell, Mark L. (Inventor)

    2001-01-01

    A method and apparatus for creating density images of an object through the 3-dimensional tracking of protons that have passed through the object are provided. More specifically, the 3-dimensional tracking of the protons is accomplished by gathering and analyzing images of the ionization tracks of the protons in a closely packed stack of scintillating fibers.

  6. High resolution Cerenkov light imaging of induced positron distribution in proton therapy

    SciTech Connect

    Yamamoto, Seiichi Fujii, Kento; Morishita, Yuki; Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

    2014-11-01

    Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy. Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a {sup 22}Na point source for the actual imaging setup. Then the transparent acrylic phantoms (100 × 100 × 100 mm{sup 3}) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera. Results: The Cerenkov light’s spatial resolution for the setup was 0.76 ± 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons. Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The authors conclude that Cerenkov light imaging of proton-induced positron is promising for proton therapy.

  7. Proton magnetic resonance spectroscopic imaging in patients with cerebellar degeneration.

    PubMed

    Tedeschi, G; Bertolino, A; Massaquoi, S G; Campbell, G; Patronas, N J; Bonavita, S; Barnett, A S; Alger, J R; Hallett, M

    1996-01-01

    Using proton magnetic resonance spectroscopic imaging, we studied the cerebellum of 9 patients with cerebellar degeneration and of 9 age-matched normal control subjects. This technique permits the simultaneous measurement of N-acetylaspartate, choline-containing compounds, creatine/phosphocreatine, and lactate signal intensities from four 15-mm slices divided into 0.84-ml single-volume elements. Because patients with cerebellar degeneration often show substantial atrophy on magnetic resonance imaging (MRI), we specifically chose to analyze the spectroscopic signals only from tissue that did not have an atrophic appearance on the MRI. The spectroscopic findings showed a significant reduction of N-acetylaspartate in all parts of the cerebellum, a significant correlation with MRI scores of cerebellar atrophy, and a significant correlation with clinical rating scores of cerebellar disturbance. Our method of analysis suggests the presence of a neurodegenerative process in cerebellar areas that do not appear to be atrophic on the MRI. Some limitations of proton magnetic resonance spectroscopic imaging in the present study were related to the partial field inhomogeneity characteristics of the posterior fossa, the anatomical location of the cerebellum, and the particularly severe cerebellar atrophy in some of the patients. PMID:8572670

  8. Reliability of proton-nuclear interaction cross section data to predict proton-induced PET images in proton therapy

    PubMed Central

    Espaa, S; Zhu, X; Daartz, J; El Fakhri, G; Bortfeld, T

    2011-01-01

    In-vivo PET range verification relies on the comparison of measured and simulated activity distributions. The accuracy of the simulated distribution depends on the accuracy of the Monte Carlo code, which is in turn dependent on the accuracy of the available cross sections data for ?+ isotope production. We have explored different cross section data available in the literature for the main reaction channels (16O(p,pn)15O, 12C(p,pn)11C and 16O(p,3p3n)11C) contributing to the production of ?+ isotopes by proton beams in patients. Available experimental and theoretical values were implemented in the simulation and compared with measured PET images obtained with a high-resolution PET scanner. Each reaction channel was studied independently. A phantom with three different materials was built, two of them with high carbon or oxygen concentration and a third one with average soft tissue composition. Monoenergetic and SOBP field irradiations of the phantom were accomplished and measured PET images were compared with simulation results. Different cross section values for the tissue-equivalent material lead to range differences below 1 mm when a 5 min scan time was employed and close to 5 mm differences for a 30 min scan time with 15 min delay between irradiation and scan (a typical off-line protocol). The results presented here emphasize the need of more accurate measurement of the cross section values of the reaction channels contributing to the production of PET isotopes by proton beams before this in-vivo range verification method can achieve mm accuracy. PMID:21464534

  9. Fatty infiltration of the liver: evaluation by proton spectroscopic imaging

    SciTech Connect

    Heiken, J.P.; Lee, J.K.; Dixon, W.T.

    1985-12-01

    The reliability of proton spectroscopic imaging in evaluating fatty infiltration of the liver was investigated in 35 subjects (12 healthy volunteers and 23 patients with fatty livers). With this modified spin-echo technique, fatty liver could be separated from normal liver both visually and quantitatively. On the opposed image, normal liver had an intermediate signal intensity, greater than that of muscle, whereas fatty liver had a lower signal intensity, equal to or less than that of muscle. In normal livers, the lipid signal fraction was less than 10%, while in fatty livers it was greater than 10% and usually exceeded 20%. With this technique, nonuniform fatty infiltration of the liver can be differentiated from hepatic metastases, and the technique may prove useful in the differentiation of some hepatic disorders.

  10. SU-E-J-175: Proton Dose Calculation On Scatter-Corrected CBCT Image: Feasibility Study for Adaptive Proton Therapy

    SciTech Connect

    Park, Y; Winey, B; Sharp, G

    2014-06-01

    Purpose: To demonstrate feasibility of proton dose calculation on scattercorrected CBCT images for the purpose of adaptive proton therapy. Methods: Two CBCT image sets were acquired from a prostate cancer patient and a thorax phantom using an on-board imaging system of an Elekta infinity linear accelerator. 2-D scatter maps were estimated using a previously introduced CT-based technique, and were subtracted from each raw projection image. A CBCT image set was then reconstructed with an open source reconstruction toolkit (RTK). Conversion from the CBCT number to HU was performed by soft tissue-based shifting with reference to the plan CT. Passively scattered proton plans were simulated on the plan CT and corrected/uncorrected CBCT images using the XiO treatment planning system. For quantitative evaluation, water equivalent path length (WEPL) was compared in those treatment plans. Results: The scatter correction method significantly improved image quality and HU accuracy in the prostate case where large scatter artifacts were obvious. However, the correction technique showed limited effects on the thorax case that was associated with fewer scatter artifacts. Mean absolute WEPL errors from the plans with the uncorrected and corrected images were 1.3 mm and 5.1 mm in the thorax case and 13.5 mm and 3.1 mm in the prostate case. The prostate plan dose distribution of the corrected image demonstrated better agreement with the reference one than that of the uncorrected image. Conclusion: A priori CT-based CBCT scatter correction can reduce the proton dose calculation error when large scatter artifacts are involved. If scatter artifacts are low, an uncorrected CBCT image is also promising for proton dose calculation when it is calibrated with the soft-tissue based shifting.

  11. Monitoring proton radiation therapy with in-room PET imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Xuping; Espaa, Samuel; Daartz, Juliane; Liebsch, Norbert; Ouyang, Jinsong; Paganetti, Harald; Bortfeld, Thomas R.; El Fakhri, Georges

    2011-07-01

    We used a mobile positron emission tomography (PET) scanner positioned within the proton therapy treatment room to study the feasibility of proton range verification with an in-room, stand-alone PET system, and compared with off-line equivalent studies. Two subjects with adenoid cystic carcinoma were enrolled into a pilot study in which in-room PET scans were acquired in list-mode after a routine fractionated treatment session. The list-mode PET data were reconstructed with different time schemes to generate in-room short, in-room long and off-line equivalent (by skipping coincidences from the first 15 min during the list-mode reconstruction) PET images for comparison in activity distribution patterns. A phantom study was followed to evaluate the accuracy of range verification for different reconstruction time schemes quantitatively. The in-room PET has a higher sensitivity compared to the off-line modality so that the PET acquisition time can be greatly reduced from 30 to <5 min. Features in deep-site, soft-tissue regions were better retained with in-room short PET acquisitions because of the collection of 15O component and lower biological washout. For soft tissue-equivalent material, the distal fall-off edge of an in-room short acquisition is deeper compared to an off-line equivalent scan, indicating a better coverage of the high-dose end of the beam. In-room PET is a promising low cost, high sensitivity modality for the in vivo verification of proton therapy. Better accuracy in Monte Carlo predictions, especially for biological decay modeling, is necessary.

  12. Noise evaluation of Compton camera imaging for proton therapy.

    PubMed

    Ortega, P G; Torres-Espallardo, I; Cerutti, F; Ferrari, A; Gillam, J E; Lacasta, C; Llosá, G; Oliver, J F; Sala, P R; Solevi, P; Rafecas, M

    2015-03-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming γ energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of detection, from the beam particle entering a phantom to the event classification, is simulated using FLUKA. The range determination is later estimated from the reconstructed image obtained from a two and three-event algorithm based on Maximum Likelihood Expectation Maximization. The neutron background and random coincidences due to a therapeutic-like time structure are analyzed for mono-energetic proton beams. The time structure of the beam is included in the simulations, which will affect the rate of particles entering the detector. PMID:25658644

  13. Noise evaluation of Compton camera imaging for proton therapy

    NASA Astrophysics Data System (ADS)

    Ortega, P. G.; Torres-Espallardo, I.; Cerutti, F.; Ferrari, A.; Gillam, J. E.; Lacasta, C.; Llos, G.; Oliver, J. F.; Sala, P. R.; Solevi, P.; Rafecas, M.

    2015-02-01

    Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming ? energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of detection, from the beam particle entering a phantom to the event classification, is simulated using FLUKA. The range determination is later estimated from the reconstructed image obtained from a two and three-event algorithm based on Maximum Likelihood Expectation Maximization. The neutron background and random coincidences due to a therapeutic-like time structure are analyzed for mono-energetic proton beams. The time structure of the beam is included in the simulations, which will affect the rate of particles entering the detector.

  14. Toward proton MR spectroscopic imaging of stimulated brain function

    SciTech Connect

    Singh, M. . Dept. of Radiology)

    1992-08-01

    With the objective of complementing local cerebral metabolic studies of PET, and as a prelude to spectroscopic imaging, the authors have performed the first localized proton spectroscopic study of the stimulated human auditory cortex. Water suppressed localized spectroscopy (voxel size 3cm [times] 3cm [times] 3cm enclosing the auditory cortex, Te = 272ms, Tr = 3s) was performed on a 1.5T MRI/MRS system and spectra were acquired during stimulation with a 1kHz tone presented at 2Hz. Measurements were conducted for 30-40 min with a temporal resolution of 3.2 min (64 averages per time block). Results included in this paper from six subjects show a lactate peak which increases during stimulation compared to baseline values. These results suggest an increase in anaerobic glycolysis during stimulation and provide unique and valuable information that should complement glucose metabolism and flood flow studies of PET.

  15. Remote sensing of the proton aurora characteristics from IMAGE-FUV

    NASA Astrophysics Data System (ADS)

    Bisikalo, D. V.; Shematovich, V. I.; Grard, J.-C.; Meurant, M.; Mende, S. B.; Frey, H. U.

    2003-11-01

    The combination of simultaneous global images of the north polar region obtained with the IMAGE-FUV imaging system makes it possible to globally map the properties of the electron and proton auroral precipitation. The SI12 imager, which observes the Doppler-shifted Lyman-a

  16. An imaging proton spectrometer for short-pulse laser plasma experiments

    SciTech Connect

    Chen, H; Hazi, A; van Maren, R; Chen, S; Fuchs, J; Gauthier, M; Pape, S L; Rygg, J R; Shepherd, R

    2010-05-11

    Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high resolution, but also provide its angular characteristics. The information obtained from this spectrometer compliments those from commonly used diagnostics including radiochromic film packs, CR39 nuclear track detectors, and non-imaging magnetic spectrometers. The basic characterizations and sample data from this instrument are presented.

  17. An imaging proton spectrometer for short-pulse laser plasma experiments

    SciTech Connect

    Chen, H; Hazi, A; van Maren, R; Chen, S; Fuchs, J; Gauthier, M; Rygg, J R; Shepherd, R

    2010-02-09

    Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better understand these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only provide at high-resolution the energy distribution, but also the protons angular characteristics. The information obtained from this spectrometer compliments those from other methods using radiochromic film packs, CR39 films and other protons spectrometers. The basic characterizations and example data from this diagnostics will be presented. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, as part of the Cimarron project funded by LDRD-09SI11.

  18. Science to Practice: Highly Shifted Proton MR imagingA Shift toward Better Cell Tracking?

    PubMed Central

    Bulte, Jeff W. M.

    2015-01-01

    Summary A hot spot magnetic resonance (MR) imaging cell tracking technique has been developed that allows direct detection of dysprosium- or thulium-1,4,7,10-tetraazacyclododecane-?,??,??,??-tetramethyl-1,4,7,10-tetraacetic acid (DOTMA)labeled protons inside cells. These highly shifted protons may allow specific detection of multiple cell types because it does not rely on acquiring the proton signal from bulk water. PMID:25153271

  19. Quantitative proton imaging from multiple physics processes: a proof of concept

    NASA Astrophysics Data System (ADS)

    Bopp, C.; Rescigno, R.; Rousseau, M.; Brasse, D.

    2015-07-01

    Proton imaging is developed in order to improve the accuracy of charged particle therapy treatment planning. It makes it possible to directly map the relative stopping powers of the materials using the information on the energy loss of the protons. In order to reach a satisfactory spatial resolution in the reconstructed images, the position and direction of each particle is recorded upstream and downstream from the patient. As a consequence of individual proton detection, information on the transmission rate and scattering of the protons is available. Image reconstruction processes are proposed to make use of this information. A proton tomographic acquisition of an anthropomorphic head phantom was simulated. The transmission rate of the particles was used to reconstruct a map of the macroscopic cross section for nuclear interactions of the materials. A two-step iterative reconstruction process was implemented to reconstruct a map of the inverse scattering length of the materials using the scattering of the protons. Results indicate that, while the reconstruction processes should be optimized, it is possible to extract quantitative information from the transmission rate and scattering of the protons. This suggests that proton imaging could provide additional knowledge on the materials that may be of use to further improve treatment planning.

  20. Fatty infiltration of the liver: demonstration by proton spectroscopic imaging: preliminary observations

    SciTech Connect

    Lee, J.K.T.; Dixon, W.T.; Ling, D.; Levitt, R.G.; Murphy, W.A. Jr.

    1984-10-01

    Two normal volunteers and three patients with CT evidence of fatty infiltration of the liver were studied to determine whether magnetic resonance imaging using a pulse sequence designed to differentiate fat and water could be used to detect fatty infiltration of the liver in human being. The magnetic resonance technique used a modified spin echo technique (simple proton spectroscopic imaging). Quantitative data showed that fatty liver can be separated from normal liver using the spin echo technique, and that the opposed image of the proton spectroscopic technique is more sensitive to small changes in hepatic fatty content than in-phase images with any echo time.

  1. Developing a phenomenological model of the proton trajectory within a heterogeneous medium required for proton imaging

    NASA Astrophysics Data System (ADS)

    Collins Fekete, Charles-Antoine; Doolan, Paul; Dias, Marta F.; Beaulieu, Luc; Seco, Joao

    2015-07-01

    To develop an accurate phenomenological model of the cubic spline path estimate of the proton path, accounting for the initial proton energy and water equivalent thickness (WET) traversed. Monte Carlo (MC) simulations were used to calculate the path of protons crossing various WET (10-30?cm) of different material (LN300, water and CB2-50% CaCO3) for a range of initial energies (180-330?MeV). For each MC trajectory, cubic spline trajectories (CST) were constructed based on the entrance and exit information of the protons and compared with the MC using the root mean square (RMS) metric. The CST path is dependent on the direction vector magnitudes (|P0,1|). First, |P0,1| is set to the proton path length (with factor ?0,1\\text{Norm} = 1.0). Then, two optimal factor ?0,1{} are introduced in |P0,1|. The factors are varied to minimize the RMS difference with MC paths for every configuration. A set of ?0,1\\text{opt} factors, function of WET/water equivalent path length (WEPL), that minimizes the RMS are presented. MTF analysis is then performed on proton radiographs of a line-pair phantom reconstructed using the CST trajectories. ?0,1\\text{opt} was fitted to the WET/WEPL ratio using a quadratic function (Y = A + BX2 where A = 1.01,0.99, B = 0.43,-??0.46 respectively for ?0\\text{opt} , ?1\\text{opt} ). The RMS deviation calculated along the path, between the CST and the MC, increases with the WET. The increase is larger when using ?0,1\\text{Norm} than ?0,1\\text{opt} (difference of 5.0% with WET/WEPL = 0.66). For 230/330?MeV protons, the MTF10% was found to increase by 40/16% respectively for a thin phantom (15?cm) when using the ?0,1\\text{opt} model compared to the ?0,1\\text{Norm} model. Calculation times for ?0,1\\text{opt} are scaled down compared to MLP and RMS deviation are similar within standard deviation. Based on the results of this study, using CST with the ?0,1\\text{opt} factors reduces the RMS deviation and increases the spatial resolution when reconstructing proton trajectories.

  2. The electron and proton aurora as seen by IMAGE-FUV and FAST

    NASA Astrophysics Data System (ADS)

    Frey, H. U.; Mende, S. B.; Carlson, C. W.; Grard, J.-C.; Hubert, B.; Spann, J.; Gladstone, R.; Immel, T. J.

    The Far Ultraviolet Instrument (FUV) on the IMAGE spacecraft observes the aurora in three different channels. One of them (SI12) is sensitive to the signal from precipitating protons, while the other two (WIC and SI13) observe auroral emissions which are not only excited by precipitating electrons, but also by protons. We examine a period when in-situ particle measurements by the FAST spacecraft were available simultaneously with global imaging with FUV. The measured electron and proton energy spectra are used to calculate the auroral brightness along the FAST orbit. The comparison with the FUV/IMAGE observations shows good quantitative agreement and demonstrates that under certain circumstances high proton fluxes may produce significant amounts of auroral FUV emission.

  3. Global Imaging of Proton and Electron Aurorae in the far Ultraviolet

    NASA Astrophysics Data System (ADS)

    Mende, S. B.; Frey, H. U.; Immel, T. J.; Gerard, J.-C.; Hubert, B.; Fuselier, S. A.

    2003-10-01

    The IMAGE spacecraft carries three FUV photon imagers, the Wideband Imaging Camera (WIC) and two channels, SI-12 and SI-13, of the Spectrographic Imager. These provide simultaneous global images, which can be interpreted in terms of the precipitating particle types (protons and electrons) and their energies. IMAGE FUV is the first space-borne global imager that can provide instantaneous global images of the proton precipitation. At times a bright auroral spot, rich in proton precipitation, is observed on the dayside, several degrees poleward of the auroral zone. The spot was identified as the footprint of the merging region of the cusp that is located on lobe field lines when IMF Bz was northward. This identification was based on compelling statistical evidence showing that the appearance and location of the spot is consistent with the IMF Bz and By directions. The intensity of the spot is well correlated with the solar wind dynamic pressure and it was found that the direct entry of solar wind particles could account for the intensity of the observed spot without the need for any additional acceleration. Another discovery was the observation of dayside sub-auroral proton arcs. These arcs were observed in the midday to afternoon MLT sector. Conjugate satellite observations showed that these arcs were generated by pure proton precipitation. Nightside auroras and their relationship to substorm phases were studied through single case studies and in a superimposed epoch analysis. It was found that generally there is substantial proton precipitation prior to substorms and the proton intensity only doubles at substorm onset while the electron auroral brightness increases on average by a factor of 5 and sometimes by as much as a factor of 10. Substorm onset occurs in the central region of the pre-existing proton precipitation. Assuming that nightside protons are precipitating from a quasi-stable ring current at its outer regions where the field lines are distorted by neutral sheet currents we can associate the onset location with this region of closed but distorted field lines relatively close to the earth. Our results also show that protons are present in the initial poleward substorm expansion however later they are over taken by the electrons. We also find that the intensity of the substorms as quantified by the intensity of the post onset electron precipitation is correlated with the intensity of the proton precipitation prior to the substorms, highlighting the role of the pre-existing near earth plasma in the production of the next substorm.

  4. Electron and proton excitation of the FUV aurora: Simultaneous IMAGE and NOAA observations

    NASA Astrophysics Data System (ADS)

    Coumans, V.; GRard, J.-C.; Hubert, B.; Evans, D. S.

    2002-11-01

    The Far Ultraviolet (FUV) imaging system on board the IMAGE satellite provides a global view of the north auroral region in different spectral channels. The Wideband Imaging Camera (WIC) is sensitive to the N2 LBH emission and NI emissions produced by both electron and proton precipitations. The SI12 camera images the Lyman-? emission due to incident protons only. We compare WIC and SI12 observations with model predictions based on particle measurements from the TED and the MEPED detectors on board NOAA-TIROS spacecraft. Models of the interaction of auroral particles with the atmosphere are used together with the in situ proton and electron flux and characteristic energy data to calculate the auroral brightness at the magnetic footprint of the NOAA-15 and NOAA-16 orbital tracks. The MEPED experiment measures the precipitating particles with energy higher than 30 keV, so that these comparisons include all auroral energies, in contrast to previous comparisons. A satisfactory agreement in morphology and in magnitude is obtained for most satellite overflights. The observed FUV-WIC signal is well modeled if the different spatial resolution of the two sensors is considered and the in situ measurements properly smoothed. The calculated count rate includes contributions from LBH emission, the NI 149.3 nm line, and the OI 135.6 nm line excited by electrons and protons. The proton contribution in WIC can locally dominate the electrons. The comparisons indicate that protons can significantly contribute to the FUV aurora at specific times and places and cannot be systematically neglected. The results confirm the shift of the proton auroral oval equatorward of the electron oval in the dusk sector. We also show that in some regions, especially in the dusk sector, high-energy protons dominate the proton energy flux and account for a large fraction of the Lyman-? and other FUV emissions.

  5. A scintillating plastic fiber tracking detector for neutron and proton imaging and spectroscopy

    NASA Astrophysics Data System (ADS)

    Ryan, J. M.; Castaneda, C. M.; Holslin, D.; Macri, J. R.; McConnell, M. L.; Romero, J. L.; Wunderer, C. B.

    1999-02-01

    We report on a prototype detector system designed to perform imaging and spectroscopy on 20-250MeV neutrons. The detection techniques employed can be applied to measurements in a variety of disciplines including solar and atmospheric physics, radiation therapy and nuclear materials monitoring. The detector measures the energy and direction of neutrons by detecting double neutron-proton scatters and recording images of the ionization tracks of the recoil protons in a densely packed bundle of scintillating plastic fibers stacked in orthogonal layers. The scintillation tracks are detected and imaged by photomultipliers and image intensifier/CCD camera optics. By tracking the recoil protons from individual neutrons, the kinematics of the scatter are determined. This directional information results in a high signal-to-noise measurement. The self-triggering and track imaging features of a prototype for tracking in two dimensions are demonstrated in calibrations with 14-65MeV neutrons, 20-67.5MeV protons, and with cosmic-ray muons. Preliminary results of phantom imaging measurements using a proton beam are also presented. We discuss several applications for this detector technique and outline future development work.

  6. Multiscale X-ray and Proton Imaging of Bismuth-Tin Solidification

    NASA Astrophysics Data System (ADS)

    Gibbs, P. J.; Imhoff, S. D.; Morris, C. L.; Merrill, F. E.; Wilde, C. H.; Nedrow, P.; Mariam, F. G.; Fezzaa, K.; Lee, W.-K.; Clarke, A. J.

    2014-08-01

    The formation of structural patterns during metallic solidification is complex and multiscale in nature, ranging from the nanometer scale, where solid-liquid interface properties are important, to the macroscale, where casting mold filling and intended heat transfer are crucial. X-ray and proton imaging can directly interrogate structure, solute, and fluid flow development in metals from the microscale to the macroscale. X-rays permit high spatio-temporal resolution imaging of microscopic solidification dynamics in thin metal sections. Similarly, high-energy protons permit imaging of mesoscopic and macroscopic solidification dynamics in large sample volumes. In this article, we highlight multiscale x-ray and proton imaging of bismuth-tin alloy solidification to illustrate dynamic measurement of crystal growth rates and solute segregation profiles that can be that can be acquired using these techniques.

  7. Transverse Imaging of the Proton in Exclusive Diffractive pp Scattering

    SciTech Connect

    Christian Weiss; Leonid Frankfurt; Charles Hyde-Wright; Mark Strikman

    2006-04-20

    In a forthcoming paper we describe a new approach to rapidity gap survival (RGS) in the production of high-mass systems (H = dijet, Higgs, etc.) in exclusive double-gap diffractive pp scattering, pp -> p + H + p. It is based on the idea that hard and soft interactions are approximately independent (QCD factorization), and allows us to calculate the RGS probability in a model-independent way in terms of the gluon generalized parton distributions (GPDs) in the colliding protons and the pp elastic scattering amplitude. Here we focus on the transverse momentum dependence of the cross section. By measuring the ''diffraction pattern'', one can perform detailed tests of the interplay of hard and soft interactions, and even extract information about the gluon GPD in the proton from the data.

  8. Gamma electron vertex imaging and application to beam range verification in proton therapy

    SciTech Connect

    Hyeong Kim, Chan; Hyung Park, Jin; Seo, Hee; Rim Lee, Han

    2012-02-15

    Purpose: This paper describes a new gamma-ray imaging method, ''gamma electron vertex imaging (GEVI)'', which can be used for precise beam range verification in proton therapy. Methods: In GEVI imaging, the high-energy gammas from a source or nuclear interactions are first converted, by Compton scattering, to electrons, which subsequently are traced by hodoscopes to determine the location of the gamma source or the vertices of the nuclear interactions. The performance of GEVI imaging for use in-beam range verification was evaluated by Monte Carlo simulations employing geant4 equipped with the QGSP{sub B}IC{sub H}P physics package. Results: Our simulation results show that GEVI imaging can determine the proton beam range very accurately, within 2-3 mm of error, even without any sophisticated analysis. The results were obtained under simplified conditions of monoenergetic pencil beams stopped in a homogeneous phantom and on the basis of the obtained results it is expected to achieve submillimeter accuracy in proton beam range measurement. Conclusions: If future experimental work confirms the simulated results presented in this paper, the use of GEVI imaging is expected to have a great potential in increasing the accuracy of proton beam range verification in a patient, resulting in significant improvement of treatment effectiveness by enabling tight conformation of radiation dose to the tumor volume and patient safety.

  9. Initial in vivo Rodent Sodium and Proton MR Imaging at 21.1 T

    PubMed Central

    Schepkin, Victor D.; Brey, William W.; Gorkov, Peter L.; Grant, Samuel C.

    2009-01-01

    The first in vivo sodium and proton MR images and localized spectra of rodents were attained using the wide bore (105 mm) high resolution 21.1 T magnet, built and operated at the National High Magnetic Field Laboratory (Tallahassee, FL). Head images of normal mice (C57BL/6J) and Fisher rats (~ 250 g) were acquired with custom designed RF probes at frequencies of 237/900 MHz for sodium and proton, respectively. Sodium MRI resolutions of ~0.125 ?L for mouse and rat heads were achieved by using a 3D back-projection pulse sequence. A gain in SNR of ~ 3 for sodium and of ~ 2 times for proton were found relative to corresponding MR images acquired at 9.4 T. 3D FLASH proton mouse images (505050 ?m3) were acquired in 90 min and corresponding rat images (100100100 ?m3) within a total time of 120 min. Both in vivo large rodent MR imaging and localized spectroscopy at the extremely high field of 21.1 T are feasible and demonstrate improved resolution and sensitivity valuable for structural and functional brain analysis. PMID:20045599

  10. Biophysical characterization of a relativistic proton beam for image-guided radiosurgery

    PubMed Central

    Yu, Zhan; Vanstalle, Marie; La Tessa, Chiara; Jiang, Guo-Liang; Durante, Marco

    2012-01-01

    We measured the physical and radiobiological characteristics of 1GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 110Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery. PMID:22843629

  11. Seasonal effects on the proton auroral precipitation observed by IMAGE-FUV

    NASA Astrophysics Data System (ADS)

    Coumans, V.; Grard, J.-C.; Hubert, B.; Meurant, M.; Mende, S. B.

    2003-04-01

    The statistical approach of the auroral electron precipitation has shown a summer/winter dissymmetry. Electron energy flux in the 1900-0300 MLT sector increases from summer to winter. The frequency of occurrence of intense aurora (with electron energy flux above 5 erg cm-2 s-1) in the dusk-to-midnight sector was observed to be 3 times higher under winter conditions (or conditions of local darkness) than under summer conditions (or in sunlight). On board the IMAGE satellite the FUV instruments monitor the aurora in three different spectral regions and especially one of them only images the auroral proton precipitation. The Wideband Imaging Camera (WIC) observes the molecular N_2 LBH and the atomic NI emissions between 140 and 180 nm. The two channels of the Spectrographic Imager (SI) respond to the Doppler shifted Lyman-? emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). The auroral proton and electron energy fluxes are calculated from the IMAGE-FUV data, relying on energy degradation and auroral emission models. We will discuss possible seasonal asymmetry in the auroral proton precipitation. A statistical study is made with FUV data from 2 successive solstices to minimize effects due to the solar activity variations.

  12. Ionospheric Conductances Due To Auroral Proton and Electron Precipitation Deduced From Image-fuv Observations.

    NASA Astrophysics Data System (ADS)

    Coumans, V.; Hubert, B.; Meurant, M.; Grard, J.-C.; Shematovich, V. I.; Bisikalo, D. V.

    The FUV instrument on the IMAGE (Imager for Magnetopause-to-Aurora Global Ex- ploration) satellite monitors the aurora in three different spectral regions. The Wide- band Imaging Camera (WIC) observes the molecular N2 LBH and the atomic NI emissions at 140-180 nm. The two channels of the Spectrographic Imager (SI) ob- serve the Doppler shifted Lyman- emission at 121.8 nm due to precipitating protons (SI12) and the electron auroral emission of OI at 135.6 nm (SI13). We calculate the Pedersen and Hall ionospheric conductances due to auroral particles based on FUV observations separately for the proton and electron precipitation. We first estimate the electron and proton energy fluxes from the FUV data, relying on energy degradation and auroral emission models. A two-stream model is used for the electron aurora while the proton aurora modeling is based on the direct Monte Carlo method, which gives a stochastic solution to the Boltzmann equations for the H+ - H beam. The electron energy is evaluated by combining observations from the three FUV instruments. For the proton energy, we use a statistical model based on in-situ particle measurements. Second, the particle energy and energy flux are used to estimate the ionization rates separately for protons and electrons, consistently with the energy degradation models. Finally, the electron and ion densities are estimated from ionization profiles, and the Pedersen and Hall conductances are calculated from fundamental equations. Appli- cations of the method to the distribution of the conductance at winter solstice in the course of substorm development over the north polar region will be illustrated.

  13. The Proton and Electron Aurora as Seen by Image-FUV and FAST

    NASA Technical Reports Server (NTRS)

    Gerard, J.-C.; Hubert, B.; Habraken, S.; Renotte, E.; Jamar, C.; Rochus, P.; Spann, J.; Gladstone, R.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    The Far Ultraviolet (FUV) instrument on IMAGE images the aurora in three different wavelength regions. The Wideband Imaging Camera (WIC) observes the molecular Lyman-Birge-Hopfield (LBH) and atomic Nitrogen emissions at 140-190 nm. The two channels of the Spectrographic Imager (SI) observe the Doppler shifted Lyman Alpha emission of precipitating protons at 121.8 nm (SI 12) and the mostly electron produced emission from oxygen OI at 135.6 nm (SI13). The major advantage of FUV compared to previously flown UV imagers is the simultaneous operation of all three imaging systems without the need for filter changes and the uncertainty of temporal changes of the aurora between exposures. The FAST satellite passes every two hours through FUV images during apogee operations. This enables a comparison between the remotely imaged particle precipitation and the in-situ measurements along the FAST track. The detailed analysis of images from all three systems together with a full simulation of auroral emissions based on in-situ measurements by FAST confirms the laboratory calibrations of FUV. The spatial resolution and image quality of WIC permits the observation of a good correspondence between in-situ and remote measurements of precipitation boundaries. The clear separation between the lower latitude proton precipitation and the more structured higher latitude electron precipitation is obtained with both SI-channels.

  14. The influence of CT image noise on proton range calculation in radiotherapy planning.

    PubMed

    Chvetsov, Alexei V; Paige, Sandra L

    2010-03-21

    The purpose of this note is to evaluate the relationship between the stochastic errors in CT numbers and the standard deviation of the computed proton beam range in radiotherapy planning. The stochastic voxel-to-voxel variation in CT numbers called 'noise,' may be due to signal registration, processing and numerical image reconstruction technique. Noise in CT images may cause a deviation in the computed proton range from the physical proton range, even assuming that the error due to CT number-stopping power calibration is removed. To obtain the probability density function (PDF) of the computed proton range, we have used the continuing slowing down approximation (CSDA) and the uncorrelated white Gaussian noise along the proton path. The model of white noise was accepted because for the slice-based fan-beam CT scanner; the power-spectrum properties apply only to the axial (x, y) domain and the noise is uncorrelated in the z domain. However, the possible influence of the noise power spectrum on the standard deviation of the range should be investigated in the future. A random number generator was utilized for noise simulation and this procedure was iteratively repeated to obtain convergence of range PDF, which approached a Gaussian distribution. We showed that the standard deviation of the range, sigma, increases linearly with the initial proton energy, computational grid size and standard deviation of the voxel values. The 95% confidence interval width of the range PDF, which is defined as 4sigma, may reach 0.6 cm for the initial proton energy of 200 MeV, computational grid 0.25 cm and 5% standard deviation of CT voxel values. Our results show that the range uncertainty due to random errors in CT numbers may be significant and comparable to the uncertainties due to calibration of CT numbers. PMID:20182006

  15. NOTE: The influence of CT image noise on proton range calculation in radiotherapy planning

    NASA Astrophysics Data System (ADS)

    Chvetsov, Alexei V.; Paige, Sandra L.

    2010-03-01

    The purpose of this note is to evaluate the relationship between the stochastic errors in CT numbers and the standard deviation of the computed proton beam range in radiotherapy planning. The stochastic voxel-to-voxel variation in CT numbers called 'noise,' may be due to signal registration, processing and numerical image reconstruction technique. Noise in CT images may cause a deviation in the computed proton range from the physical proton range, even assuming that the error due to CT number-stopping power calibration is removed. To obtain the probability density function (PDF) of the computed proton range, we have used the continuing slowing down approximation (CSDA) and the uncorrelated white Gaussian noise along the proton path. The model of white noise was accepted because for the slice-based fan-beam CT scanner; the power-spectrum properties apply only to the axial (x, y) domain and the noise is uncorrelated in the z domain. However, the possible influence of the noise power spectrum on the standard deviation of the range should be investigated in the future. A random number generator was utilized for noise simulation and this procedure was iteratively repeated to obtain convergence of range PDF, which approached a Gaussian distribution. We showed that the standard deviation of the range, ?, increases linearly with the initial proton energy, computational grid size and standard deviation of the voxel values. The 95% confidence interval width of the range PDF, which is defined as 4?, may reach 0.6 cm for the initial proton energy of 200 MeV, computational grid 0.25 cm and 5% standard deviation of CT voxel values. Our results show that the range uncertainty due to random errors in CT numbers may be significant and comparable to the uncertainties due to calibration of CT numbers. Presented at the 51st Annual Meeting of the American Association of Physicists in Medicine, Anaheim, CA, July 26-30, 2009.

  16. A nested phosphorus and proton coil array for brain magnetic resonance imaging and spectroscopy.

    PubMed

    Brown, Ryan; Lakshmanan, Karthik; Madelin, Guillaume; Parasoglou, Prodromos

    2016-01-01

    A dual-nuclei radiofrequency coil array was constructed for phosphorus and proton magnetic resonance imaging and spectroscopy of the human brain at 7T. An eight-channel transceive degenerate birdcage phosphorus module was implemented to provide whole-brain coverage and significant sensitivity improvement over a standard dual-tuned loop coil. A nested eight-channel proton module provided adequate sensitivity for anatomical localization without substantially sacrificing performance on the phosphorus module. The developed array enabled phosphorus spectroscopy, a saturation transfer technique to calculate the global creatine kinase forward reaction rate, and single-metabolite whole-brain imaging with 1.4cm nominal isotropic resolution in 15min (2.3cm actual resolution), while additionally enabling 1mm isotropic proton imaging. This study demonstrates that a multi-channel array can be utilized for phosphorus and proton applications with improved coverage and/or sensitivity over traditional single-channel coils. The efficient multi-channel coil array, time-efficient pulse sequences, and the enhanced signal strength available at ultra-high fields can be combined to allow volumetric assessment of the brain and could provide new insights into the underlying energy metabolism impairment in several neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases, as well as mental disorders such as schizophrenia. PMID:26375209

  17. A knowledge-based imaging informatics approach to managing patients treated with proton beam therapy

    NASA Astrophysics Data System (ADS)

    Liu, B. J.; Huang, H. K.; Law, M.; Le, Anh; Documet, Jorge; Gertych, Arek

    2007-03-01

    Last year we presented work on an imaging informatics approach towards developing quantitative knowledge and tools based on standardized DICOM-RT objects for Image-Guided Radiation Therapy. In this paper, we have extended this methodology to perform knowledge-based medical imaging informatics research on specific clinical scenarios where brain tumor patients are treated with Proton Beam Therapy (PT). PT utilizes energized charged particles, protons, to deliver dose to the target region. Protons are energized to specific velocities which determine where they will deposit maximum energy within the body to destroy cancerous cells. Treatment Planning is similar in workflow to traditional Radiation Therapy methods such as Intensity-Modulated Radiation Therapy (IMRT) which utilizes a priori knowledge to drive the treatment plan in an inverse manner. In March 2006, two new RT Objects were drafted in a DICOM-RT Supplement 102 specifically for Ion Therapy which includes Proton Therapy. The standardization of DICOM-RT-ION objects and the development of a knowledge base as well as decision-support tools that can be add-on features to the ePR DICOM-RT system were researched. We have developed a methodology to perform knowledge-based medical imaging informatics research on specific clinical scenarios. This methodology can be used to extend to Proton Therapy and the development of future clinical decision-making scenarios during the course of the patient's treatment that utilize "inverse treatment planning". In this paper, we present the initial steps toward extending this methodology for PT and lay the foundation for development of future decision-support tools tailored to cancer patients treated with PT. By integrating decision-support knowledge and tools designed to assist in the decision-making process, a new and improved "knowledge-enhanced treatment planning" approach can be realized.

  18. Phantom based evaluation of CT to CBCT image registration for proton therapy dose recalculation

    NASA Astrophysics Data System (ADS)

    Landry, Guillaume; Dedes, George; Zllner, Christoph; Handrack, Josefine; Janssens, Guillaume; Orban de Xivry, Jonathan; Reiner, Michael; Paganelli, Chiara; Riboldi, Marco; Kamp, Florian; Shn, Matthias; Wilkens, Jan J.; Baroni, Guido; Belka, Claus; Parodi, Katia

    2015-01-01

    The ability to perform dose recalculation on the anatomy of the day is important in the context of adaptive proton therapy. The objective of this study was to investigate the use of deformable image registration (DIR) and cone beam CT (CBCT) imaging to generate the daily stopping power distribution of the patient. We investigated the deformation of the planning CT scan (pCT) onto daily CBCT images to generate a virtual CT (vCT) using a deformable phantom designed for the head and neck (H & N) region. The phantom was imaged at a planning CT scanner in planning configuration, yielding a pCT and in deformed, treatment day configuration, yielding a reference CT (refCT). The treatment day configuration was additionally scanned at a CBCT scanner. A Morphons DIR algorithm was used to generate a vCT. The accuracy of the vCT was evaluated by comparison to the refCT in terms of corresponding features as identified by an adaptive scale invariant feature transform (aSIFT) algorithm. Additionally, the vCT CT numbers were compared to those of the refCT using both profiles and regions of interest and the volumes and overlap (DICE coefficients) of various phantom structures were compared. The water equivalent thickness (WET) of the vCT, refCT and pCT were also compared to evaluate proton range differences. Proton dose distributions from the same initial fluence were calculated on the refCT, vCT and pCT and compared in terms of proton range. The method was tested on a clinical dataset using a replanning CT scan acquired close in time to a CBCT scan as reference using the WET evaluation. Results from the aSIFT investigation suggest a deformation accuracy of 2-3?mm. The use of the Morphon algorithm did not distort CT number intensity in uniform regions and WET differences between vCT and refCT were of the order of 2% of the proton range. This result was confirmed by proton dose calculations. The patient results were consistent with phantom observations. In conclusion, our phantom study suggests the vCT approach is adequate for proton dose recalculation on the basis of CBCT imaging.

  19. Predicting image blur in proton radiography: comparisons between measurements and Monte Carlo simulations

    SciTech Connect

    von Wittenau, A; Aufderheide, M B; Henderson, G L

    2010-05-07

    Given the cost and lead-times involved in high-energy proton radiography, it is prudent to model proposed radiographic experiments to see if the images predicted would return useful information. We recently modified our raytracing transmission radiography modeling code HADES to perform simplified Monte Carlo simulations of the transport of protons in a proton radiography beamline. Beamline objects include the initial diffuser, vacuum magnetic fields, windows, angle-selecting collimators, and objects described as distorted 2D (planar or cylindrical) meshes or as distorted 3D hexahedral meshes. We present an overview of the algorithms used for the modeling and code timings for simulations through typical 2D and 3D meshes. We next calculate expected changes in image blur as scattering materials are placed upstream and downstream of a resolution test object (a 3 mm thick sheet of tantalum, into which 0.4 mm wide slits have been cut), and as the current supplied to the focusing magnets is varied. We compare and contrast the resulting simulations with the results of measurements obtained at the 800 MeV Los Alamos LANSCE Line-C proton radiography facility.

  20. D-D proton spectra and emission imaging for diagnosing imploded capsules on Shenguang III laser prototype facility

    NASA Astrophysics Data System (ADS)

    Teng, Jian; Zhang, Tiankui; Pu, Yudong; Wu, Bo; Hong, Wei; Zhu, Bin; He, Weihua; Lu, Feng; Shan, Lianqiang; Wen, Xianlun; Zhou, Weimin; Cao, Leifeng; Jiang, Shaoen; Gu, Yuqiu

    2013-10-01

    Understanding and controlling implosion dynamics are critical for progress in inertial confinement fusion (ICF). Primary D-D protons spectra and emission imaging is used for diagnosing areal density and implosion asymmetries on Shenguang III laser prototype facility with low neutron yields for the first time. An accurately calibrated charged particle spectrometer (CPS) is used with CR39 detector for the measurement of the proton spectra. The properties of the noise and proton signal on the CR39 are characterized, and the spectra of the implosion proton are obtained by excluding the noise. For the investigation of the implosion asymmetries, a new method of directly imaging of primary DD protons in the implosion region by miniature magnetic quadrupole lenses is proposed. The imaging properties such as spatial resolution and focus length are investigated by simulation and calibration experiment.

  1. Fine phantom image from laser-induced proton radiography with a spatial resolution of several μm

    NASA Astrophysics Data System (ADS)

    Son, Jaebum; Lee, Cheol Ho; Kang, Jeongsoo; Jang, Doh-Yun; Park, Junesic; Kim, Yun Ho; Kim, Yong Kyun; Choi, Chang Il; Kim, I. Jong; Choi, Il Woo; Sung, Jae Hee; Lee, Seong Ku; Jeong, Tae Moon; Lee, Chang-Lyoul; Yu, Tae Jun; Lee, Jongmin

    2014-07-01

    The advantages of a laser-driven proton acceleration have prompted studies of laser-induced proton radiography. As the CR-39 solid-state nuclear-track detector is suitable for measuring charged particles and can be used in proton radiography, we studied laser-induced proton radiography with the CR-39 for several years, and we were able to obtain a spatial resolution of about 10 μm. For obtaining an image with a spatial resolution of a few μm, we investigated the effect of the CR-39 etching conditions on the spatial resolution and carried out imaging experiments using fine phantoms. Experiments were performed using the 100-TW titanium-sapphire laser system at the Advanced Photonics Research Institute of the Gwangju Institute of Science Technology. We have demonstrated that images with a spatial resolution of about several μm can be achieved using laser-induced proton radiography.

  2. Experimental Study of Calculated t1 Images Under Flow Conditions Using Protons and FLUORINE-19 in Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Jie

    A gradient refocused echo (GRE) pulse protocol has been developed and implemented to obtain calculated T1 images under flow conditions. This sequence acquires multiple images with different flip angles and uses a least -square fit to obtain calculated T1 images. A theoretical analysis of imprecision in the calculated T1 images is discussed. In accordance with Wang (49), the optimal parameters as determined by computer simulation were found to be 20 ^circ and 100^ circ for the flip angles in a two point fit for TR falling in the range 0.3 to 1.0 T1. Flow compensation was added to the pulse sequence for imaging flow phantoms containing GD-DTPA doped water and perfluorocarbon (PFC) compounds for a range of flow rates (0-55 cm/s). Flow compensation was found to effectively recover signal loss due to flow related dephasing. Experimental testing of this protocol has been performed on stationary proton and PFC compound phantoms utilizing ^1H and ^{19}F magnetic resonance imaging respectively. There is good agreement between the experimental results and the theoretical predictions about imprecision in the calculated T1 images. Analysis of variance of the mean T1 values of the calculated T1 images of the proton and PFC flow phantoms indicated that for the flow phantom geometry used in this study, there was no statistical difference among these mean T1 values from flow phantoms with different flow rates (including stationary status). It is believed that this protocol may provide an imaging method for mapping the pO _2 distribution in the vascular space in vivo utilizing perfluorocarbon compounds and ^ {19}F magnetic resonance imaging.

  3. Imaging of Plasmas using Proton Beams Generated by Ultra-Intense Laser Pulses

    SciTech Connect

    Borghesi, M,; Campbell, D.H.; Clarke, R.J.; Galimberti, M.; Gizzi, L.A.; Haines, M.G.; Mackinnon, A.J.; Schiavi, A.; Willi, O.

    2002-01-15

    Proton imaging is a diagnostic with enormous potential for the investigation of fundamental plasma physics problems which were impossible to explore up to now. By using this diagnostic, for the first time the measurement of transient electric fields in dense plasmas has been obtained, determining their evolution on a picosecond scale with micrometric spatial resolution. The data is of great relevance to Inertial Confinement Fusion both in the conventional and Fast Ignitor approach. Detailed analysis and modeling is presently undergoing.

  4. Evaluation of a multistage CdZnTe Compton camera for prompt ? imaging for proton therapy

    NASA Astrophysics Data System (ADS)

    McCleskey, M.; Kaye, W.; Mackin, D. S.; Beddar, S.; He, Z.; Polf, J. C.

    2015-06-01

    A new detector system, Polaris J from H3D, has been evaluated for its potential application as a Compton camera (CC) imaging device for prompt ? rays (PGs) emitted during proton radiation therapy (RT) for the purpose of dose range verification. This detector system consists of four independent CdZnTe detector stages and a coincidence module, allowing the user to construct a Compton camera in different geometrical configurations and to accept both double and triple scatter events. Energy resolution for the 662 keV line from 137Cs was found to be 9.7 keV FWHM. The raw absolute efficiencies for double and triple scatter events were 2.2 10-5 and 5.8 10-7, respectively, for ?s from a 60Co source. The position resolution for the reconstruction of a point source from the measured CC data was about 2 mm. Overall, due to the low efficiency of the Polaris J CC, the current system was deemed not viable for imaging PGs emitted during proton RT treatment delivery. However, using a validated Monte Carlo model of the CC, we found that by increasing the size of the detectors and placing them in a two stage configuration, the efficiency could be increased to a level to make PG imaging possible during proton RT.

  5. Prompt gamma imaging of proton pencil beams at clinical dose rate

    NASA Astrophysics Data System (ADS)

    Perali, I.; Celani, A.; Bombelli, L.; Fiorini, C.; Camera, F.; Clementel, E.; Henrotin, S.; Janssens, G.; Prieels, D.; Roellinghoff, F.; Smeets, J.; Stichelbaut, F.; Vander Stappen, F.

    2014-10-01

    In this work, we present experimental results of a prompt gamma camera for real-time proton beam range verification. The detection system features a pixelated Cerium doped lutetium based scintillation crystal, coupled to Silicon PhotoMultiplier arrays, read out by dedicated electronics. The prompt gamma camera uses a knife-edge slit collimator to produce a 1D projection of the beam path in the target on the scintillation detector. We designed the detector to provide high counting statistics and high photo-detection efficiency for prompt gamma rays of several MeV. The slit design favours the counting statistics and could be advantageous in terms of simplicity, reduced cost and limited footprint. We present the description of the realized gamma camera, as well as the results of the characterization of the camera itself in terms of imaging performance. We also present the results of experiments in which a polymethyl methacrylate phantom was irradiated with proton pencil beams in a proton therapy center. A tungsten slit collimator was used and prompt gamma rays were acquired in the 3-6 MeV energy range. The acquisitions were performed with the beam operated at 100 MeV, 160 MeV and 230 MeV, with beam currents at the nozzle exit of several nA. Measured prompt gamma profiles are consistent with the simulations and we reached a precision (2?) in shift retrieval of 4 mm with 0.5 108, 1.4 108 and 3.4 108 protons at 100, 160 and 230 MeV, respectively. We conclude that the acquisition of prompt gamma profiles for in vivo range verification of proton beam with the developed gamma camera and a slit collimator is feasible in clinical conditions. The compact design of the camera allows its integration in a proton therapy treatment room and further studies will be undertaken to validate the use of this detection system during treatment of real patients.

  6. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor

    NASA Astrophysics Data System (ADS)

    Rugar, D.; Mamin, H. J.; Sherwood, M. H.; Kim, M.; Rettner, C. T.; Ohno, K.; Awschalom, D. D.

    2015-02-01

    Magnetic resonance imaging, with its ability to provide three-dimensional, elementally selective imaging without radiation damage, has had a revolutionary impact in many fields, especially medicine and the neurosciences. Although challenging, its extension to the nanometre scale could provide a powerful new tool for the nanosciences, especially if it can provide a means for non-destructively visualizing the full three-dimensional morphology of complex nanostructures, including biomolecules. To achieve this potential, innovative new detection strategies are required to overcome the severe sensitivity limitations of conventional inductive detection techniques. One successful example is magnetic resonance force microscopy, which has demonstrated three-dimensional imaging of proton NMR with resolution on the order of 10 nm, but with the requirement of operating at cryogenic temperatures. Nitrogen-vacancy (NV) centres in diamond offer an alternative detection strategy for nanoscale magnetic resonance imaging that is operable at room temperature. Here, we demonstrate two-dimensional imaging of 1H NMR from a polymer test sample using a single NV centre in diamond as the sensor. The NV centre detects the oscillating magnetic field from precessing protons as the sample is scanned past the NV centre. A spatial resolution of ˜12 nm is shown, limited primarily by the scan resolution.

  7. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor.

    PubMed

    Rugar, D; Mamin, H J; Sherwood, M H; Kim, M; Rettner, C T; Ohno, K; Awschalom, D D

    2015-02-01

    Magnetic resonance imaging, with its ability to provide three-dimensional, elementally selective imaging without radiation damage, has had a revolutionary impact in many fields, especially medicine and the neurosciences. Although challenging, its extension to the nanometre scale could provide a powerful new tool for the nanosciences, especially if it can provide a means for non-destructively visualizing the full three-dimensional morphology of complex nanostructures, including biomolecules. To achieve this potential, innovative new detection strategies are required to overcome the severe sensitivity limitations of conventional inductive detection techniques. One successful example is magnetic resonance force microscopy, which has demonstrated three-dimensional imaging of proton NMR with resolution on the order of 10 nm, but with the requirement of operating at cryogenic temperatures. Nitrogen-vacancy (NV) centres in diamond offer an alternative detection strategy for nanoscale magnetic resonance imaging that is operable at room temperature. Here, we demonstrate two-dimensional imaging of (1)H NMR from a polymer test sample using a single NV centre in diamond as the sensor. The NV centre detects the oscillating magnetic field from precessing protons as the sample is scanned past the NV centre. A spatial resolution of ∼12 nm is shown, limited primarily by the scan resolution. PMID:25531089

  8. Improved spectral data unfolding for radiochromic film imaging spectroscopy of laser-accelerated proton beams

    SciTech Connect

    Schollmeier, M.; Geissel, M.; Sefkow, A. B.; Flippo, K. A.

    2014-04-15

    An improved method to unfold the space-resolved proton energy distribution function of laser-accelerated proton beams using a layered, radiochromic film (RCF) detector stack has been developed. The method takes into account the reduced RCF response near the Bragg peak due to a high linear energy transfer (LET). This LET dependence of the active RCF layer has been measured, and published data have been re-interpreted to find a nonlinear saturation scaling of the RCF response with stopping power. Accounting for the LET effect increased the integrated particle yield by 25% after data unfolding. An iterative, analytical, space-resolved deconvolution of the RCF response functions from the measured dose was developed that does not rely on fitting. After the particle number unfold, three-dimensional interpolation is performed to determine the spatial proton beam distribution for proton energies in-between the RCF data points. Here, image morphing has been implemented as a novel interpolation method that takes into account the energy-dependent, changing beam topology.

  9. Lasers As Particle Accelerators In Medicine: From Laser-Driven Protons To Imaging With Thomson Sources

    SciTech Connect

    Pogorelsky, I. V.; Babzien, M.; Polyanskiy, M. N.; Yakimenko, V.; Dover, N. P.; Palmer, C. A. J.; Najmudin, Z.; Shkolnikov, P.; Williams, O.; Rosenzweig, J.; Oliva, P.; Carpinelli, M.; Golosio, B.; Delogu, P.; Stefanini, A.; Endrizzi, M.

    2011-06-01

    We report our recent progress using a high-power, picosecond CO{sub 2} laser for Thomson scattering and ion acceleration experiments. These experiments capitalize on certain advantages of long-wavelength CO{sub 2} lasers, such as their high number of photons per energy unit and beneficial wavelength- scaling of the electrons' ponderomotive energy and critical plasma frequency. High X-ray fluxes produced in the interactions of the counter-propagating laser- and electron-beams for obtaining single-shot, high-contrast images of biological objects. The laser, focused on a hydrogen jet, generated a monoenergetic proton beam via the radiation-pressure mechanism. The energy of protons produced by this method scales linearly with the laser's intensity. We present a plan for scaling the process into the range of 100-MeV proton energy via upgrading the CO{sub 2} laser. This development will enable an advance to the laser-driven proton cancer therapy.

  10. Advances in functional and structural imaging of the human lung using proton MRI.

    PubMed

    Miller, G Wilson; Mugler, John P; Sá, Rui C; Altes, Talissa A; Prisk, G Kim; Hopkins, Susan R

    2014-12-01

    The field of proton lung MRI is advancing on a variety of fronts. In the realm of functional imaging, it is now possible to use arterial spin labeling (ASL) and oxygen-enhanced imaging techniques to quantify regional perfusion and ventilation, respectively, in standard units of measurement. By combining these techniques into a single scan, it is also possible to quantify the local ventilation-perfusion ratio, which is the most important determinant of gas-exchange efficiency in the lung. To demonstrate potential for accurate and meaningful measurements of lung function, this technique was used to study gravitational gradients of ventilation, perfusion, and ventilation-perfusion ratio in healthy subjects, yielding quantitative results consistent with expected regional variations. Such techniques can also be applied in the time domain, providing new tools for studying temporal dynamics of lung function. Temporal ASL measurements showed increased spatial-temporal heterogeneity of pulmonary blood flow in healthy subjects exposed to hypoxia, suggesting sensitivity to active control mechanisms such as hypoxic pulmonary vasoconstriction, and illustrating that to fully examine the factors that govern lung function it is necessary to consider temporal as well as spatial variability. Further development to increase spatial coverage and improve robustness would enhance the clinical applicability of these new functional imaging tools. In the realm of structural imaging, pulse sequence techniques such as ultrashort echo-time radial k-space acquisition, ultrafast steady-state free precession, and imaging-based diaphragm triggering can be combined to overcome the significant challenges associated with proton MRI in the lung, enabling high-quality three-dimensional imaging of the whole lung in a clinically reasonable scan time. Images of healthy and cystic fibrosis subjects using these techniques demonstrate substantial promise for non-contrast pulmonary angiography and detailed depiction of airway disease. Although there is opportunity for further optimization, such approaches to structural lung imaging are ready for clinical testing. PMID:24990096

  11. Advances in Functional and Structural Imaging of the Human Lung Using Proton MRI

    PubMed Central

    Miller, G. Wilson; Mugler, John P.; S, Rui C.; Altes, Talissa A.; Prisk, G. Kim; Hopkins, Susan R.

    2014-01-01

    The field of proton lung MRI is advancing on a variety of fronts. In the realm of functional imaging, it is now possible to use arterial spin labeling (ASL) and oxygen-enhanced imaging techniques to quantify regional perfusion and ventilation, respectively, in standard units of measure. By combining these techniques into a single scan, it is also possible to quantify the local ventilation-perfusion ratio, which is the most important determinant of gas-exchange efficiency in the lung. To demonstrate potential for accurate and meaningful measurements of lung function, this technique was used to study gravitational gradients of ventilation, perfusion, and ventilation-perfusion ratio in healthy subjects, yielding quantitative results consistent with expected regional variations. Such techniques can also be applied in the time domain, providing new tools for studying temporal dynamics of lung function. Temporal ASL measurements showed increased spatial-temporal heterogeneity of pulmonary blood flow in healthy subjects exposed to hypoxia, suggesting sensitivity to active control mechanisms such as hypoxic pulmonary vasoconstriction, and illustrating that to fully examine the factors that govern lung function it is necessary to consider temporal as well as spatial variability. Further development to increase spatial coverage and improve robustness would enhance the clinical applicability of these new functional imaging tools. In the realm of structural imaging, pulse sequence techniques such as ultrashort echo-time (UTE) radial k-space acquisition, ultrafast steady-state free precession (SSFP), and imaging-based diaphragm triggering can be combined to overcome the significant challenges associated with proton MRI in the lung, enabling high-quality three-dimensional imaging of the whole lung in a clinically reasonable scan time. Images of healthy and cystic fibrosis subjects using these techniques demonstrate substantial promise for non-contrast pulmonary angiography and detailed depiction of airway disease. Although there is opportunity for further optimization, such approaches to structural lung imaging are ready for clinical testing. PMID:24990096

  12. Major Solar Proton Event during September 24-30, 2001 using Imaging Riometer Technique (P42)

    NASA Astrophysics Data System (ADS)

    Sharma, A. K.; Vhatkar, R. S.

    2006-11-01

    sharma_ashokkumar@yahoo.com Major outbursts of mass and energy i.e. a fast full halo CME with speed of 2402 km/sec from region 9632, located on the Sun at S16 E23 was observed at 1030 UT by SOHO/LASCO C3 coronagraph on September 24, 2001. The proton event at greater than 100 MeV began at 1440 UT on 24 September, reached a maximum of 31.2 PFU at 0755 UT on 25 September and ended at 1940 UT on 26 September 2001. The protons event at greater than 10 MeV began at 1215 UT on 24 September, reached a maximum of 12,900 PFU at 2235 UT on 25 September and ended at 1710 UT on 30 September 2001. These extremely high energetic protons accelerated during CMEs produces significant ionization in the D region of the ionosphere at high latitudes. Increase in ionization in the D region causes cosmic noise absorption. The major Polar Cap Absorption (PCA) observed during SEPTEMBER 24 -30, 2001 will be discussed in this paper. Imaging riometer observations were made from Kilpisjarvi (69.05oN; 20.79oW), Northern Finland during the PCA event. For this the remote and insitu data have been used. The imaging riometer for ionospheric studies (IRIS) is used to quantify the intensity, time of occurrence and location of CME effects on the ionosphere.

  13. Comparison of scintillators for single shot imaging of laser accelerated proton beams

    NASA Astrophysics Data System (ADS)

    Cook, Nathan

    2012-03-01

    The application of intense laser pulses incident on specialized targets provides exciting new means for generating energetic beams of protons and ions. Recent work has demonstrated the utility of these beams of particles in a variety of applications, from inertial confinement fusion to radiation therapy. These applications require precise control, and subsequently precise feedback from the beam. Imaging techniques can provide the necessary shot-to-shot characterization to be effective as diagnostics. However, the utility of imaging methods scales with the capability of scintillating materials to emit well characterized and consistent radiation upon irradiance by a charged particle beam. We will discuss three candidates for an ideal diagnostic for MeV range protons and light ions. CsI:Tl^+ and Al2O3:Cr^3+ are two inorganic scintillators which exhibit excellent response to hadrons in this energy range. They are compared with the combination diagnostic micro-channel plate with a P43 phosphor screen, which offers advantages in refresh rate and resolution over direct exposure methods. Ultimately we will determine which candidate performs optimally as part of a robust, inexpensive diagnostic for laser accelerated protons and light ions.

  14. Magnetic properties, water proton relaxivities, and in-vivo MR images of paramagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Gang Ho; Chang, Yongmin

    2015-07-01

    In this mini review, magnetic resonance imaging (MRI) contrast agents based on lanthanideoxide (Ln2O3) nanoparticles are described. Ln2O3 (Ln = Gd, Dy, Ho, and Er) nanoparticles are paramagnetic, but show appreciable magnetic moments at room temperature and even at ultrasmall particle diameters. Among Ln2O3 nanoparticles, Gd2O3 nanoparticles show larger longitudinal water proton relaxivity (r1) values than Gd-chelates because of the large amount of Gd in the nanoparticle, and the other Ln2O3 nanoparticles (Ln = Dy, Ho, and Er) show appreciable transverse water proton relaxivity (r2) values. Therefore, Gd2O3 nanoparticles are potential T1 MRI contrast agents while the other Ln2O3 nanoparticles are potential T2 MRI contrast agents at high MR fields.

  15. Imaging the Proton Concentration and Mapping the Spatial Distribution of the Electric Field of Catalytic Micropumps

    NASA Astrophysics Data System (ADS)

    Farniya, A. Afshar; Esplandiu, M. J.; Reguera, D.; Bachtold, A.

    2013-10-01

    Catalytic engines can use hydrogen peroxide as a chemical fuel in order to drive motion at the microscale. The chemo-mechanical actuation is a complex mechanism based on the interrelation between catalytic reactions and electro-hydrodynamics phenomena. We studied catalytic micropumps using fluorescence confocal microscopy to image the concentration of protons in the liquid. In addition, we measured the motion of particles with different charges in order to map the spatial distributions of the electric field, the electrostatic potential and the fluid flow. The combination of these two techniques allows us to contrast the gradient of the concentration of protons against the spatial variation in the electric field. We present numerical simulations that reproduce the experimental results. Our work sheds light on the interrelation between the different processes at work in the chemomechanical actuation of catalytic pumps. Our experimental approach could be used to study other electrochemical systems with heterogeneous electrodes.

  16. WE-D-BRF-05: Quantitative Dual-Energy CT Imaging for Proton Stopping Power Computation

    SciTech Connect

    Han, D; Williamson, J; Siebers, J

    2014-06-15

    Purpose: To extend the two-parameter separable basis-vector model (BVM) to estimation of proton stopping power from dual-energy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the Bethe-Bloch equation. We have implemented an idealized post-processing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrene-water and water-CaCl2 solution basis pairs for soft tissues and bony tissues, respectively. The coefficients of 24 standard ICRU tissue compositions were estimated by pDECT. The corresponding ρe, Iex, and stopping power tables were evaluated via BVM and compared to tabulated ICRU 44 reference values. Results: BVM-based pDECT was found to estimate ρe and Iex with average and maximum errors of 0.5% and 2%, respectively, for the 24 tissues. Proton stopping power values at 175 MeV, show average/maximum errors of 0.8%/1.4%. For adipose, muscle and bone, these errors result range prediction accuracies less than 1%. Conclusion: A new two-parameter separable DECT model (BVM) for estimating proton stopping power was developed. Compared to competing parametric fit DECT models, BVM has the comparable prediction accuracy without necessitating iterative solution of nonlinear equations or a sample-dependent empirical relationship between effective atomic number and Iex. Based on the proton BVM, an efficient iterative statistical DECT reconstruction model is under development.

  17. Projection imaging with directional electron and proton beams emitted from an ultrashort intense laser-driven thin foil target

    NASA Astrophysics Data System (ADS)

    Nishiuchi, M.; Choi, I. W.; Daido, H.; Nakamura, T.; Pirozhkov, A. S.; Yogo, A.; Ogura, K.; Sagisaka, A.; Orimo, S.; Daito, I.; Bulanov, S. V.; Sung, J. H.; Lee, S. K.; Yu, T. J.; Jeong, T. M.; Kim, I. J.; Kim, C. M.; Kang, S. W.; Pae, K. H.; Oishi, Y.; Lee, J.

    2015-02-01

    Projection images of a metal mesh produced by directional MeV electron beam together with directional proton beam, emitted simultaneously from a thin foil target irradiated by an ultrashort intense laser, are recorded on an imaging plate for the electron imaging and on a CR-39 nuclear track detector for the proton imaging. The directional electron beam means the portion of the electron beam which is emitted along the same direction (i.e., target normal direction) as the proton beam. The mesh patterns are projected to each detector by the electron beam and the proton beam originated from tiny virtual sources of ~20 µm and ~10 µm diameters, respectively. Based on the observed quality and magnification of the projection images, we estimate sizes and locations of the virtual sources for both beams and characterize their directionalities. To carry out physical interpretation of the directional electron beam qualitatively, we perform 2D particle-in-cell simulation which reproduces a directional escaping electron component, together with a non-directional dragged-back electron component, the latter mainly contributes to building a sheath electric field for proton acceleration. The experimental and simulation results reveal various possible applications of the simultaneous, synchronized electron and proton sources to radiography and pump-probe measurements with temporal resolution of ~ps and spatial resolution of a few tens of µm.

  18. Dayside Proton Aurora: Comparisons between Global MHD Simulations and Image Observations

    NASA Technical Reports Server (NTRS)

    Berchem, J.; Fuselier, S. A.; Petrinec, S.; Frey, H. U.; Burch, J. L.

    2003-01-01

    The IMAGE mission provides a unique opportunity to evaluate the accuracy of current global models of the solar wind interaction with the Earth's magnetosphere. In particular, images of proton auroras from the Far Ultraviolet Instrument (FUV) onboard the IMAGE spacecraft are well suited to support investigations of the response of the Earth's magnetosphere to interplanetary disturbances. Accordingly, we have modeled two events that occurred on June 8 and July 28, 2000, using plasma and magnetic field parameters measured upstream of the bow shock as input to three-dimensional magnetohydrodynamic (MHD) simulations. This paper begins with a discussion of images of proton auroras from the FUV SI-12 instrument in comparison with the simulation results. The comparison showed a very good agreement between intensifications in the auroral emissions measured by FUV SI-12 and the enhancement of plasma flows into the dayside ionosphere predicted by the global simulations. Subsequently, the IMAGE observations are analyzed in the context of the dayside magnetosphere's topological changes in magnetic field and plasma flows inferred from the simulation results. Finding include that the global dynamics of the auroral proton precipitation patterns observed by IMAGE are consistent with magnetic field reconnection occurring as a continuous process while the iMF changes in direction and the solar wind dynamic pressure varies. The global simulations also indicate that some of the transient patterns observed by IMAGE are consistent with sporadic reconnection processes. Global merging patterns found in the simulations agree with the antiparallel merging model. though locally component merging might broaden the merging region, especially in the region where shocked solar wind discontinuities first reach the magnetopause. Finally, the simulations predict the accretion of plasma near the bow shock in the regions threaded by newly open field lines on which plasma flows into the dayside ionosphere are enhanced. Overall the results of these initial comparisons between global MHD simulation results and IMAGE observations emphasize the interplay between reconnection and dynamic pressure processes at the dayside magnetopause. as well as the intricate connection between the bow shock and the auroral region.

  19. Determination of electron and proton auroral energy inputs from FUV-IMAGE

    NASA Astrophysics Data System (ADS)

    Grard, J.; Hubert, B.; Meurant, M.; Frey, H. U.; Mende, S. B.; Immel, T.; Bisikalo, D. V.; Shematovich, V. I.; Gladstone, G. R.

    2001-05-01

    The FUV experiment onboard the IMAGE spacecraft offers the unique possibility to obtain simultaneous snapshots of the global north aurora every 2 minutes in three different spectral channels. The WIC camera has a broadband channel covering the 135-190 nm interval including the N2 LBH bands, part of which may be absorbed by O2. The SI13 channel is centered on the OI 135.6 nm line which is optically thin and includes a ~ 40% LBH contribution. Finally, the SI12 camera images the Doppler-shifted Ly-? emission excited by the proton aurora. This set of instrumentation is combined with auroral models to determine the electron and the proton energy fluxes from the magnetosphere. Examples will be presented and compared with the values deduced from the NOAA satellites. Simultaneous in-situ measurements of the particle characteristic energy have been combined with the data extracted from the FUV images to validate the models and derive empirical relationships between the particle flux measured by the detectors and the brightness observed by FUV-IMAGE at the footprint of the same magnetic field line. Finally, we will assess the ability to deduce the characteristic energy of the auroral particles from the ratio of co-registered images in the WIC and SI13 cameras. This method is based on the difference of vertical distribution of the LBH and the OI 135.6 nm emissions. It offers the potential to globally remotely sense not only the energy flux from the magnetosphere but also the main features of the electron characteristic energy.

  20. The effects of mapping CT images to Monte Carlo materials on GEANT4 proton simulation accuracy

    SciTech Connect

    Barnes, Samuel; McAuley, Grant; Slater, James; Wroe, Andrew

    2013-04-15

    Purpose: Monte Carlo simulations of radiation therapy require conversion from Hounsfield units (HU) in CT images to an exact tissue composition and density. The number of discrete densities (or density bins) used in this mapping affects the simulation accuracy, execution time, and memory usage in GEANT4 and other Monte Carlo code. The relationship between the number of density bins and CT noise was examined in general for all simulations that use HU conversion to density. Additionally, the effect of this on simulation accuracy was examined for proton radiation. Methods: Relative uncertainty from CT noise was compared with uncertainty from density binning to determine an upper limit on the number of density bins required in the presence of CT noise. Error propagation analysis was also performed on continuously slowing down approximation range calculations to determine the proton range uncertainty caused by density binning. These results were verified with Monte Carlo simulations. Results: In the presence of even modest CT noise (5 HU or 0.5%) 450 density bins were found to only cause a 5% increase in the density uncertainty (i.e., 95% of density uncertainty from CT noise, 5% from binning). Larger numbers of density bins are not required as CT noise will prevent increased density accuracy; this applies across all types of Monte Carlo simulations. Examining uncertainty in proton range, only 127 density bins are required for a proton range error of <0.1 mm in most tissue and <0.5 mm in low density tissue (e.g., lung). Conclusions: By considering CT noise and actual range uncertainty, the number of required density bins can be restricted to a very modest 127 depending on the application. Reducing the number of density bins provides large memory and execution time savings in GEANT4 and other Monte Carlo packages.

  1. Proton-Electron Double-Resonance Imaging of pH using phosphonated trityl probe

    PubMed Central

    Takahashi, Wataru; Bobko, Andrey A.; Dhimitruka, Ilirian; Hirata, Hiroshi; Zweier, Jay L.; Samouilov, Alexandre

    2014-01-01

    Variable Radio Frequency Proton-Electron Double-Resonance Imaging (VRF PEDRI) enables extracting a functional map from a limited number of images acquired at pre-selected EPR frequencies using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. In this work we explored potential of VRF PEDRI for pH mapping of aqueous samples using recently synthesized pH-sensitive phosphonated trityl radical, pTR. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of pTR probe allows for a pH map extraction. Long relaxation times of pTR allow for pH mapping at EPR irradiation power as low as 1.25 W during 130 s acquisition time with spatial resolution of about 1 mm. This is particularly important for in vivo applications enabling one to avoid sample overheating by reducing RF power deposition. PMID:25530673

  2. Femtoelectron-Based Terahertz Imaging of Hydration State in a Proton Exchange Membrane Fuel Cell

    NASA Astrophysics Data System (ADS)

    Buaphad, P.; Thamboon, P.; Kangrang, N.; Rhodes, M. W.; Thongbai, C.

    2015-08-01

    Imbalanced water management in a proton exchange membrane (PEM) fuel cell significantly reduces the cell performance and durability. Visualization of water distribution and transport can provide greater comprehension toward optimization of the PEM fuel cell. In this work, we are interested in water flooding issues that occurred in flow channels on cathode side of the PEM fuel cell. The sample cell was fabricated with addition of a transparent acrylic window allowing light access and observed the process of flooding formation (in situ) via a CCD camera. We then explore potential use of terahertz (THz) imaging, consisting of femtoelectron-based THz source and off-angle reflective-mode imaging, to identify water presence in the sample cell. We present simulations of two hydration states (water and nonwater area), which are in agreement with the THz image results. A line-scan plot is utilized for quantitative analysis and for defining spatial resolution of the image. Implementing metal mesh filtering can improve spatial resolution of our THz imaging system.

  3. Short-lived positron emitters in beam-on PET imaging during proton therapy.

    PubMed

    Dendooven, P; Buitenhuis, H J T; Diblen, F; Heeres, P N; Biegun, A K; Fiedler, F; van Goethem, M-J; van der Graaf, E R; Brandenburg, S

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of (10)C, T1/2??=??19?s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: (12)N (T1/2??=??11?ms) on carbon (9% of (11)C), (29)P (T1/2??=??4.1?s) on phosphorus (20% of (30)P) and (38m)K (T1/2??=??0.92?s) on calcium (113% of (38g)K). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, (12)N dominates up to 70?s. On bone tissue, (12)N dominates over (15)O during the first 8-15?s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70?s irradiation. From the estimated number of (12)N PET counts, we conclude that, for any tissue, (12)N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of (12)N PET imaging is discussed. PMID:26539812

  4. Short-lived positron emitters in beam-on PET imaging during proton therapy

    NASA Astrophysics Data System (ADS)

    Dendooven, P.; Buitenhuis, H. J. T.; Diblen, F.; Heeres, P. N.; Biegun, A. K.; Fiedler, F.; van Goethem, M.-J.; van der Graaf, E. R.; Brandenburg, S.

    2015-12-01

    The only method for in vivo dose delivery verification in proton beam radiotherapy in clinical use today is positron emission tomography (PET) of the positron emitters produced in the patient during irradiation. PET imaging while the beam is on (so called beam-on PET) is an attractive option, providing the largest number of counts, the least biological washout and the fastest feedback. In this implementation, all nuclides, independent of their half-life, will contribute. As a first step towards assessing the relevance of short-lived nuclides (half-life shorter than that of 10C, T1/2  =  19 s) for in vivo dose delivery verification using beam-on PET, we measured their production in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T1/2  =  11 ms) on carbon (9% of 11C), 29P (T1/2  =  4.1 s) on phosphorus (20% of 30P) and 38mK (T1/2  =  0.92 s) on calcium (113% of 38gK). No short-lived nuclides are produced on oxygen. The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 12N dominates over 15O during the first 8–15 s (depending on carbon-to-oxygen ratio). The short-lived nuclides created on phosphorus and calcium provide 2.5 times more beam-on PET counts than the long-lived ones produced on these elements during a 70 s irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, 12N PET imaging potentially provides equal to superior proton range information compared to prompt gamma imaging with an optimized knife-edge slit camera. The practical implementation of 12N PET imaging is discussed.

  5. Sensitivity study of proton radiography and comparison with kV and MV x-ray imaging using GEANT4 Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Depauw, Nicolas; Seco, Joao

    2011-04-01

    The imaging sensitivity of proton radiography has been studied and compared with kV and MV x-ray imaging using Monte Carlo simulations. A phantom was specifically modeled using 21 different material inserts with densities ranging from 0.001 to 1.92 g cm-3. These simulations were run using the MGH double scattered proton beam, scanned pencil proton beams from 200 to 490 MeV, as well as pure 50 keV, 100 keV, 1 MeV and 2 MeV gamma x-ray beams. In order to compare the physics implied in both proton and photon radiography without being biased by the current state of the art in detector technology, the detectors were considered perfect. Along with spatial resolution, the contrast-to-noise ratio was evaluated and compared for each material. These analyses were performed using radiographic images that took into account the following: only primary protons, both primary and secondary protons, and both contributions while performing angular and energetic cuts. Additionally, tissue-to-tissue contrasts in an actual lung cancer patient case were studied for simulated proton radiographs and compared against the original kV x-ray image which corresponds to the current patient set-up image in the proton clinic. This study highlights the poorer spatial resolution of protons versus x-rays for radiographic imaging purposes, and the excellent density resolution of proton radiography. Contrasts around the tumor are higher using protons in a lung cancer patient case. The high-density resolution of proton radiography is of great importance for specific tumor diagnostics, such as in lung cancer, where x-ray radiography operates poorly. Furthermore, the use of daily proton radiography prior to proton therapy would ameliorate patient set-up while reducing the absorbed dose delivered through imaging.

  6. Proton imaging of siloxanes to map tissue oxygenation levels (PISTOL): a tool for quantitative tissue oximetry.

    PubMed

    Kodibagkar, Vikram D; Wang, Xianghui; Pacheco-Torres, Jesús; Gulaka, Praveen; Mason, Ralph P

    2008-10-01

    Hexamethyldisiloxane (HMDSO) has been identified as a sensitive proton NMR indicator of tissue oxygenation (pO(2)) based on spectroscopic spin-lattice relaxometry. A rapid MRI approach has now been designed, implemented, and tested. The technique, proton imaging of siloxanes to map tissue oxygenation levels (PISTOL), utilizes frequency-selective excitation of the HMDSO resonance and chemical-shift selective suppression of residual water signal to effectively eliminate water and fat signals and pulse-burst saturation recovery (1)H echo planar imaging to map T(1) of HMDSO and hence pO(2). PISTOL was used here to obtain maps of pO(2) in rat thigh muscle and Dunning prostate R3327 MAT-Lu tumor-implanted rats. Measurements were repeated to assess baseline stability and response to breathing of hyperoxic gas. Each pO(2) map was obtained in 3(1/2) min, facilitating dynamic measurements of response to oxygen intervention. Altering the inhaled gas to oxygen produced a significant increase in mean pO(2) from 55 Torr to 238 Torr in thigh muscle and a smaller, but significant, increase in mean pO(2) from 17 Torr to 78 Torr in MAT-Lu tumors. Thus, PISTOL enabled mapping of tissue pO(2) at multiple locations and dynamic changes in pO(2) in response to intervention. This new method offers a potentially valuable new tool to image pO(2) in vivo for any healthy or diseased state by (1)H MRI. PMID:18574806

  7. Absolute calibration of photostimulable image plate detectors used as (0.5-20 MeV) high-energy proton detectors

    SciTech Connect

    Mancic, A.; Fuchs, J.; Antici, P.; Audebert, P.; Gaillard, S. A.

    2008-07-15

    In this paper, the absolute calibration of photostimulable image plates (IPs) used as proton detectors is presented. The calibration is performed in a wide range of proton energies (0.5-20 MeV) by exposing simultaneously the IP and calibrated detectors (radiochromic films and solid state detector CR39) to a source of broadband laser-accelerated protons, which are spectrally resolved. The final result is a calibration curve that enables retrieving the proton number from the IP signal.

  8. In-beam PET imaging for on-line adaptive proton therapy: an initial phantom study

    NASA Astrophysics Data System (ADS)

    Shao, Yiping; Sun, Xishan; Lou, Kai; Zhu, Xiaorong R.; Mirkovic, Dragon; Poenisch, Falk; Grosshans, David

    2014-07-01

    We developed and investigated a positron emission tomography (PET) system for use with on-line (both in-beam and intra-fraction) image-guided adaptive proton therapy applications. The PET has dual rotating depth-of-interaction measurable detector panels by using solid-state photomultiplier (SSPM) arrays and LYSO scintillators. It has a 44 mm diameter trans-axial and 30 mm axial field-of-view (FOV). A 38 mm diameter polymethyl methacrylate phantom was placed inside the FOV. Both PET and phantom axes were aligned with a collimated 179.2 MeV beam. Each beam delivered 50 spills (0.5 s spill and 1.5 s inter-spill time, 3.8 Gy at Bragg peak). Data from each beam were acquired with detectors at a given angle. Nine datasets for nine beams with detectors at nine different angles over 180 were acquired for full-tomographic imaging. Each dataset included data both during and 5 min after irradiations. The positron activity-range was measured from the PET image reconstructed from all nine datasets and compared to the results from simulated images. A 22Na disc-source was also imaged after each beam to monitor the PET system's performance. PET performed well except for slight shifts of energy photo-peak positions (<1%) after each beam, due mainly to the neutron exposure of SSPM that increased the dark-count noise. This minor effect was corrected offline with a shifting 350-650 keV energy window for each dataset. The results show a fast converging of activity-ranges measured by the prototype PET with high sensitivity and uniform resolution. Sub-mm activity-ranges were achieved with minimal 6 s acquisition time and three spill irradiations. These results indicate the feasibility of PET for intra-fraction beam-range verification. Further studies are needed to develop and apply a novel clinical PET system for on-line image-guided adaptive proton therapy.

  9. In-beam PET imaging for on-line adaptive proton therapy: an initial phantom study.

    PubMed

    Shao, Yiping; Sun, Xishan; Lou, Kai; Zhu, Xiaorong R; Mirkovic, Dragon; Poenisch, Falk; Grosshans, David

    2014-07-01

    We developed and investigated a positron emission tomography (PET) system for use with on-line (both in-beam and intra-fraction) image-guided adaptive proton therapy applications. The PET has dual rotating depth-of-interaction measurable detector panels by using solid-state photomultiplier (SSPM) arrays and LYSO scintillators. It has a 44mm diameter trans-axial and 30mm axial field-of-view (FOV). A 38mm diameter polymethyl methacrylate phantom was placed inside the FOV. Both PET and phantom axes were aligned with a collimated 179.2 MeV beam. Each beam delivered ?50 spills (0.5s spill and 1.5s inter-spill time, 3.8 Gy at Bragg peak). Data from each beam were acquired with detectors at a given angle. Nine datasets for nine beams with detectors at nine different angles over 180 were acquired for full-tomographic imaging. Each dataset included data both during and 5min after irradiations. The positron activity-range was measured from the PET image reconstructed from all nine datasets and compared to the results from simulated images. A (22)Na disc-source was also imaged after each beam to monitor the PET system's performance. PET performed well except for slight shifts of energy photo-peak positions (<1%) after each beam, due mainly to the neutron exposure of SSPM that increased the dark-count noise. This minor effect was corrected offline with a shifting 350-650keV energy window for each dataset. The results show a fast converging of activity-ranges measured by the prototype PET with high sensitivity and uniform resolution. Sub-mm activity-ranges were achieved with minimal 6s acquisition time and three spill irradiations. These results indicate the feasibility of PET for intra-fraction beam-range verification. Further studies are needed to develop and apply a novel clinical PET system for on-line image-guided adaptive proton therapy. PMID:24874943

  10. In vivo verification of proton beam path by using post-treatment PET/CT imaging

    SciTech Connect

    Hsi, Wen C.; Indelicato, Daniel J.; Vargas, Carlos; Duvvuri, Srividya; Li Zuofeng; Palta, Jatinder

    2009-09-15

    Purpose: The purpose of this study is to establish the in vivo verification of proton beam path by using proton-activated positron emission distributions. Methods: A total of 50 PET/CT imaging studies were performed on ten prostate cancer patients immediately after daily proton therapy treatment through a single lateral portal. The PET/CT and planning CT were registered by matching the pelvic bones, and the beam path of delivered protons was defined in vivo by the positron emission distribution seen only within the pelvic bones, referred to as the PET-defined beam path. Because of the patient position correction at each fraction, the marker-defined beam path, determined by the centroid of implanted markers seen in the post-treatment (post-Tx) CT, is used for the planned beam path. The angular variation and discordance between the PET- and marker-defined paths were derived to investigate the intrafraction prostate motion. For studies with large discordance, the relative location between the centroid and pelvic bones seen in the post-Tx CT was examined. The PET/CT studies are categorized for distinguishing the prostate motion that occurred before or after beam delivery. The post-PET CT was acquired after PET imaging to investigate prostate motion due to physiological changes during the extended PET acquisition. Results: The less than 2 deg. of angular variation indicates that the patient roll was minimal within the immobilization device. Thirty of the 50 studies with small discordance, referred as good cases, show a consistent alignment between the field edges and the positron emission distributions from the entrance to the distal edge. For those good cases, average displacements are 0.6 and 1.3 mm along the anterior-posterior (D{sub AP}) and superior-inferior (D{sub SI}) directions, respectively, with 1.6 mm standard deviations in both directions. For the remaining 20 studies demonstrating a large discordance (more than 6 mm in either D{sub AP} or D{sub SI}), 13 studies, referred as motion-after-Tx cases, also show large misalignment between the field edge and the positron emission distribution in lipomatous tissues around the prostate. These motion-after-Tx cases correspond to patients with large changes in volume of rectal gas between the post-Tx and the post-PET CTs. The standard deviations for D{sub AP} and D{sub SI} are 5.0 and 3.0 mm, respectively, for these motion-after-Tx cases. The final seven studies, referred to as position-error cases, which had a large discordance but no misalignment, were found to have deviations of 4.6 and 3.6 mm in D{sub AP} and D{sub SI}, respectively. The position-error cases correspond to a large discrepancy on the relative location between the centroid and pelvic bones seen in post-Tx CT and recorded x-ray radiographs. Conclusions: Systematic analyses of proton-activated positron emission distributions provide patient-specific information on prostate motion ({sigma}{sub M}) and patient position variability ({Sigma}{sub p}) during daily proton beam delivery. The less than 2 mm of displacement variations in the good cases indicates that population-based values of {Sigma}{sub p} and {sigma}{sub M} used in margin algorithms for treatment planning at the authors' institution are valid for the majority of cases. However, a small fraction of PET/CT studies (approximately 14%) with {approx}4 mm displacement variations may require different margins. Such data are useful in establishing patient-specific planning target volume margins.

  11. Design of a Nested Eight-Channel Sodium and Four-Channel Proton Coil for 7 Tesla Knee Imaging

    PubMed Central

    Brown, Ryan; Madelin, Guillaume; Lattanzi, Riccardo; Chang, Gregory; Regatte, Ravinder R.; Sodickson, Daniel K.; Wiggins, Graham C.

    2012-01-01

    The critical design aim for a dual-tuned sodium/proton coil is to maximize sodium sensitivity and transmit field (B1+) homogeneity while simultaneously providing adequate proton sensitivity and homogeneity. While most dual-frequency coils utilize lossy high-impedance trap circuits or PIN diodes to allow dual-resonance, we explored a nested-coil design for sodium/proton knee imaging at 7T. A stand-alone eight-channel sodium receive array was implemented without standard dual-resonance circuitry to provide improved sodium signal-to-noise ratio (SNR) over a volume coil. A detunable sodium birdcage was added for homogeneous sodium excitation and a four-channel proton transmit-receive array was added to provide anatomical reference imaging and B0 shimming capability. Both modules were implemented with minimal disturbance to the eight-channel sodium array by managing their respective resonances and geometrical arrangement. In vivo sodium SNR was 1.2 to 1.7 times greater in the developed eight-channel array than in a mono-nuclear sodium birdcage coil, while the developed four-channel proton array provided SNR similar to that of a commercial mono-nuclear proton birdcage coil. PMID:22887123

  12. Novel gradient echo sequence-based amide proton transfer magnetic resonance imaging in hyperacute cerebral infarction

    PubMed Central

    HUANG, DEXIAO; LI, SHENKAI; DAI, ZHUOZHI; SHEN, ZHIWEI; YAN, GEN; WU, RENHUA

    2015-01-01

    In the progression of ischemia, pH is important and is essential in elucidating the association between metabolic disruption, lactate formation, acidosis and tissue damage. Chemical exchange-dependent saturation transfer (CEST) imaging can be used to detect tissue pH and, in particular, a specific form of CEST magnetic resonance imaging (MRI), termed amide proton transfer (APT) MRI, which is sensitive to pH and can detect ischemic lesions, even prior to diffusion abnormalities. The critical parameter governing the ability of CEST to detect pH is the sequence. In the present study, a novel strategy was used, based on the gradient echo sequence (GRE), which involved the insertion of a magnetization transfer pulse in each repetition time (TR) and minimizing the TR for in vivo APT imaging. The proposed GRE-APT MRI method was initially verified using a tissue-like pH phantom and optimized MRI parameters for APT imaging. In order to assess the range of acute cerebral infarction, rats (n=4) were subjected to middle cerebral artery occlusion (MCAO) and MRI scanning at 7 telsa (T). Hyperacute ischemic tissue damage was characterized using multiparametric imaging techniques, including diffusion, APT and T2-Weighted MRI. By using a magnetization transfer pulse and minimizing TR, GRE-APT provided high spatial resolution and a homogeneous signal, with clearly distinguished cerebral anatomy. The GRE-APT and diffusion MRI were significantly correlated with lactate content and the area of cerebral infarction in the APT and apparent diffusion coefficient (ADC) maps matched consistently during the hyperacute period. In addition, compared with the infarction area observed on the ADC MRI map, the APT map contained tissue, which had not yet been irreversibly damaged. Therefore, GRE-APT MRI waa able to detect ischemic lactic acidosis with sensitivity and spatiotemporal resolution, suggesting the potential use of pH MRI as a surrogate imaging marker of impaired tissue metabolism for the diagnosis and prognosis of hyperacute stroke. PMID:25571956

  13. Neurochemistry of Drug Action: Insights from Proton Magnetic Resonance Spectroscopic Imaging And Their Relevance to Addiction

    PubMed Central

    Licata, Stephanie C.; Renshaw, Perry F.

    2011-01-01

    Proton magnetic resonance spectroscopy (1H MRS) is a non-invasive imaging technique that permits measurement of particular compounds or metabolites within the tissue of interest. In the brain, 1H MRS provides a snapshot of the neurochemical environment within a defined volume of interest. A search of the literature demonstrates the widespread utility of this technique for characterizing tumors, tracking the progress of neurodegenerative disease, and for understanding the neurobiological basis of psychiatric disorders. As of relatively recently, 1H MRS has found its way into substance abuse research, and it is beginning to become recognized as a valuable complement in the brain imaging toolbox that also contains positron emission tomography (PET), single photon emission computed tomography (SPECT), and functional magnetic resonance imaging (fMRI). Drug abuse studies employing 1H MRS have identified a number biochemical changes in the brain. The most consistent alterations across drug class were reductions in N-acetylaspartate and elevations in myo-inositol, while changes in choline, creatine, and amino acid transmitters also were abundant. Together, the studies discussed herein provide evidence that drugs of abuse may have a profound impact on neuronal health, energy metabolism and maintenance, inflammatory processes, cell membrane turnover, and neurotransmission, and these biochemical changes may underlie the neuropathology within brain tissue that subsequently gives rise to the cognitive and behavioral impairments associated with drug addiction. PMID:20201852

  14. CBCT/CBDT equipped with the x-ray projection system for image-guided proton therapy

    NASA Astrophysics Data System (ADS)

    Cho, Min Kook; Kim, Jin Sung; Cho, Young-Bin; Youn, Hanbean; Park, Sung Yong; Cho, Seungryong; Kim, Ho Kyung

    2009-02-01

    For image-guided proton therapy, we investigated the feasibility of CBCT (cone-beam computed tomography) and CBDT (cone-beam digital tomosynthesis) technologies in the gantry treatment room. A fully equipped x-ray projection system, which was originally operated for patient alignment, in parallel to proton-beam direction was utilized for acquiring CBCT/CBDT. The performance of the imaging detector was analyzed in terms of MTF (modulation-transfer function), NPS (noise-power spectrum) and DQE (detective quantum efficiency). Tomographic imaging performances, such as spatial resolving power, linearity of CT numbers, SNR (signal-to-noise ratio), and CNR (contrast-to-noise ratio), were analyzed by using the AAPM (American Association of Physicists in Medicine) CT QC phantom. Geometric alignment of CBCT/CBDT system was analyzed by using a calibration phantom, which consists of steal ball bearings. The determined calibration parameters were applied to the image reconstruction procedures. The overall CBCT performances of the system were demonstrated with reconstructed humanoid phantom images. In addition, we implemented the CBDT with a selected number of projection views acquired for CBCT in limited angle ranges. From the reconstructed phantom images, the CBCT system in the gantry treatment room will be very useful as a primary patient alignment system for image-guided proton therapy. The CBDT may provide fast patient positioning with less motion artifact and patient doses.

  15. Deformable motion reconstruction for scanned proton beam therapy using on-line x-ray imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; Knopf, A.; Tanner, C.; Boye, D.; Lomax, A. J.

    2013-12-01

    Organ motion is a major problem for any dynamic radiotherapy delivery technique, and is particularly so for spot scanned proton therapy. On the other hand, the use of narrow, magnetically deflected proton pencil beams is potentially an ideal delivery technique for tracking tumour motion on-line. At PSI, our new Gantry is equipped with a Beams Eye View (BEV) imaging system which will be able to acquire 2D x-ray images in fluoroscopy mode during treatment delivery. However, besides precisely tracking motion from BEVs, it is also essential to obtain information on the 3D motion vector throughout the whole region of interest, and any sparsely acquired surrogate motion is generally not sufficient to describe the deformable behaviour of the whole volume in three dimensions. In this study, we propose a method by which 3D deformable motions can be estimated from surrogate motions obtained using this monoscopic imaging system. The method assumes that example motions over a number of breathing cycles can be acquired before treatment for each patient using 4DMRI. In this study, for each of 11 different subjects, 100 continuous breathing cycles have been extracted from extended 4DMRI studies in the liver and then subject specific motion models have been built using principle component analysis (PCA). To simulate treatment conditions, a different set of 30 continuous breathing cycles from the same subjects have then been used to generate a set of simulated 4DCT data sets (so-called 4DCT(MRI) data sets), from which time-resolved digitally reconstructed radiographs (DRRs) were calculated using the BEV geometry for three treatment fields respectively. From these DRRs, surrogate motions from fiducial markers or the diaphragm have been used as a predictor to estimate 3D motions in the liver region for each subject. The prediction results have been directly compared to the ground truth motions extracted from the same 30 breath cycles of the originating 4DMRI data set. Averaged over all 11 subjects, and for three field directions, for 99% of predicted positions, median (max) error magnitudes of better than 2.63(5.67) mm can be achieved when fiducial markers was chosen as predictor. Furthermore, three single fields, 4D dose calculations have been performed as a verification tool to evaluate the prediction performance of such a model in the context of scanned proton beam therapy. These show a high similarity between plans considering either PCA predicted motion or ground truth motion, where absolute dose differences of more than 5% (Vdosediff = 5%) occur for the worst field scenarios in only 3.61% (median) or 15.13% (max) of dose calculation points in the irradiated volume. The magnitude of these dose differences were insignificantly dependent on whether surrogate motions were tracked by monoscopic or stereoscopic imaging systems, or whether fiducial markers or diaphragm were chosen as surrogate. This study has demonstrated that on-line deformable motion reconstruction from sparse surrogate motions is feasible, even when using only a monoscopic imaging system. In addition, it has also been found that diaphragm motion can be considered as a good predictor for respiratory deformable liver motion prediction, implying that fiducial markers might not be compulsory if used in conjunction with a patient specific PCA based model.

  16. Response functions of Fuji imaging plates to monoenergetic protons in the energy range 0.6-3.2 MeV

    SciTech Connect

    Bonnet, T.; Denis-Petit, D.; Gobet, F.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Aleonard, M. M.

    2013-01-15

    We have measured the responses of Fuji MS, SR, and TR imaging plates (IPs) to protons with energies ranging from 0.6 to 3.2 MeV. Monoenergetic protons were produced with the 3.5 MV AIFIRA (Applications Interdisciplinaires de Faisceaux d'Ions en Region Aquitaine) accelerator at the Centre d'Etudes Nucleaires de Bordeaux Gradignan (CENBG). The IPs were irradiated with protons backscattered off a tantalum target. We present the photo-stimulated luminescence response of the IPs together with the fading measurements for these IPs. A method is applied to allow correction of fading effects for variable proton irradiation duration. Using the IP fading corrections, a model of the IP response function to protons was developed. The model enables extrapolation of the IP response to protons up to proton energies of 10 MeV. Our work is finally compared to previous works conducted on Fuji TR IP response to protons.

  17. Serial proton magnetic resonance spectroscopic imaging, contrast-enhanced magnetic resonance imaging, and quantitative lesion volumetry in multiple sclerosis.

    PubMed

    Narayana, P A; Doyle, T J; Lai, D; Wolinsky, J S

    1998-01-01

    Serial magnetic resonance (MR) studies that included proton MR spectroscopic imaging (MRSI), contrast-enhanced MR imaging (MRI), and lesion volumetric studies were performed on 25 multiple sclerosis (MS) patients with mild to modest clinical deficits. Each patient was scanned at varying intervals for up to 2 years, resulting in a total of 124 usable MR sessions. In these longitudinal studies, metabolic changes were observed on MRSI for some subjects before the appearance of lesions on MRI scanning. Regional changes in metabolite levels were observed to be dynamic and reversible in some patients. Transient changes in N-acetylaspartate (NAA) levels were sometimes found in acute plaques and indicate that a reduced NAA level does not necessarily imply axonal loss. An inverse correlation between the average NAA within the spectroscopic volume and the total lesion volume in the whole brain was observed. This negative correlation implies that NAA can serve as an objective marker of the disease burden. Strong lipid peaks in the absence of gadolinium enhancement and MRI-defined lesions were observed in 4 patients. This observation suggests that demyelination can occur independent of perivenous inflammatory changes and supports the presence of more than one pathophysiological process leading to demyelination in MS. PMID:9450769

  18. Proton-induced Random Telegraph Signal in the CMOS imaging sensor for JANUS, the visible imaging telescope on JUICE

    NASA Astrophysics Data System (ADS)

    Winstone, G. P.; Soman, M. R.; Allanwood, E. A. H.; Holland, A. D.; Gow, J. P. D.; Stefanov, K.; Leese, M.

    2015-09-01

    JUpiter ICy moons Explorer (JUICE) is an ESA L class mission due for launch in 2022 as part of the agency's Cosmic Vision program [1][2]. The primary science goal is to explore and characterise Jupiter and several of its potentially habitable icy moons, particularly Ganymede, Europa and Callisto. The JANUS instrument is designated to be the scientific imager on-board the spacecraft with a wavelength range between 400 nm and 1000 nm and consists of a catoptric telescope coupled to a CMOS detector [3], specifically the CIS115 monolithic active pixel sensor supplied by e2v technologies[3]. A CMOS sensor has been chosen due to a combination of the high radiation tolerance required for all systems aboard the spacecraft and its capability of operating with integration times as low as 1 ms, which is required to prevent blur when imaging the moons at fast ground velocities since the camera has no mechanical shutter. However, an important consideration of using CMOS in high radiation environments is the generation of defects or defect clusters that result in pixels exhibiting Random Telegraph Signal (RTS)[5]. A study of RTS effects in the CIS115 has been undertaken, and the method applied to identify pixels in the array that display RTS behaviour is discussed and individual RTS-exhibiting pixels are characterised. The changes observed in RTS behaviour following irradiation of the CIS115 with protons is presented and the temperature dependence of the RTS behaviour is studied. The implications on the camera design and imaging requirements of the mission are examined.

  19. Measuring radial profiles of nuclear burn in ICF implosions at OMEGA and the NIF using proton emission imaging

    NASA Astrophysics Data System (ADS)

    Seguin, F. H.; Rinderknecht, H. G.; Rosenberg, M.; Zylstra, A.; Frenje, J.; Li, C. K.; Petrasso, R.; Marshall, F. J.; Sangster, T. C.; Hoffman, N. M.; Amendt, P. A.; Bellei, C.; Le Pape, S.; Wilks, S. C.

    2014-10-01

    Fusion reactions in ICF implosions of D3He-filled capsules produce 14.7-MeV D3He protons and 3-MeV DD protons. Measurements of the spatial distributions of the D3He and DD reactions are studied with a penumbral imaging system that utilizes a CR-39-based imaging detector to simultaneously record separate penumbral images of the two types of protons. Measured burn profiles are useful for studying implosion physics and provide a critical test for benchmarking simulations. Recent implosions at OMEGA of CD capsules containing 3He gas fill and SiO2 capsules containing low-pressure D3He gas were expected to have hollow D3He burn profiles (in the 3He-filled capsule, due to fuel-shell mix), but penumbral imaging showed that the reactions were centrally peaked due to enhanced ion diffusion. The imaging technique is to be implemented soon on the NIF. This work was supported in part by NLUF, DOE, and LLE.

  20. Proton Radiography

    NASA Astrophysics Data System (ADS)

    Morris, Christopher L.

    2000-04-01

    Intermediate energy protons are being used for flash radiography. Proton beams provide a flexible time format, excellent position resolution, and adjustable contrast, for a wide range of experiments. Short pulses of protons, provided by the LANSCE 800 MeV linear accelerator at Los Alamos National Laboratory, are dispersed and focused using magnetic lenses. The transmitted beam is then imaged on a detector plane using a magnetic lens . The magnet lens system images scattering angles in the object at an intermediate location. Angle collimators at this location are used to optimize the scene contrast for specific experiments. A system of gated, CCD cameras is used to obtain up to 7 time frames per experiment. More time frames can be obtained by using a second proton lens and image plane, or by using framing cameras. Multiple images have been obtained with pulse spacings as small as 357 ns. Static images have also been taking with 25 GeV protons using a lens system installed in the U line at the AGS at Brookhaven National Laboratory. This technology is rapidly evolving. Recent developments include reconfiguring the lenses to magnify the image, replacing the collimators with beam blockers to image the scattered beam rather than the transmitted beam, and the development of new detector technologies that will provide more dynamic range and more frames.

  1. A linear, separable two-parameter model for dual energy CT imaging of proton stopping power computation

    PubMed Central

    Han, Dong; Siebers, Jeffrey V.; Williamson, Jeffrey F.

    2016-01-01

    Purpose: To evaluate the accuracy and robustness of a simple, linear, separable, two-parameter model (basis vector model, BVM) in mapping proton stopping powers via dual energy computed tomography (DECT) imaging. Methods: The BVM assumes that photon cross sections (attenuation coefficients) of unknown materials are linear combinations of the corresponding radiological quantities of dissimilar basis substances (i.e., polystyrene, CaCl2 aqueous solution, and water). The authors have extended this approach to the estimation of electron density and mean excitation energy, which are required parameters for computing proton stopping powers via the Bethe–Bloch equation. The authors compared the stopping power estimation accuracy of the BVM with that of a nonlinear, nonseparable photon cross section Torikoshi parametric fit model (VCU tPFM) as implemented by the authors and by Yang et al. [“Theoretical variance analysis of single- and dual-energy computed tomography methods for calculating proton stopping power ratios of biological tissues,” Phys. Med. Biol. 55, 1343–1362 (2010)]. Using an idealized monoenergetic DECT imaging model, proton ranges estimated by the BVM, VCU tPFM, and Yang tPFM were compared to International Commission on Radiation Units and Measurements (ICRU) published reference values. The robustness of the stopping power prediction accuracy of tissue composition variations was assessed for both of the BVM and VCU tPFM. The sensitivity of accuracy to CT image uncertainty was also evaluated. Results: Based on the authors’ idealized, error-free DECT imaging model, the root-mean-square error of BVM proton stopping power estimation for 175 MeV protons relative to ICRU reference values for 34 ICRU standard tissues is 0.20%, compared to 0.23% and 0.68% for the Yang and VCU tPFM models, respectively. The range estimation errors were less than 1 mm for the BVM and Yang tPFM models, respectively. The BVM estimation accuracy is not dependent on tissue type and proton energy range. The BVM is slightly more vulnerable to CT image intensity uncertainties than the tPFM models. Both the BVM and tPFM prediction accuracies were robust to uncertainties of tissue composition and independent of the choice of reference values. This reported accuracy does not include the impacts of I-value uncertainties and imaging artifacts and may not be achievable on current clinical CT scanners. Conclusions: The proton stopping power estimation accuracy of the proposed linear, separable BVM model is comparable to or better than that of the nonseparable tPFM models proposed by other groups. In contrast to the tPFM, the BVM does not require an iterative solving for effective atomic number and electron density at every voxel; this improves the computational efficiency of DECT imaging when iterative, model-based image reconstruction algorithms are used to minimize noise and systematic imaging artifacts of CT images. PMID:26745952

  2. Proton therapy monitoring by Compton imaging: influence of the large energy spectrum of the prompt-γ radiation.

    PubMed

    Hilaire, Estelle; Sarrut, David; Peyrin, Françoise; Maxim, Voichiţa

    2016-04-21

    In proton therapy, the prompt-γ (PG) radiation produced by the interactions between protons and matter is related to the range of the beam in the patient. Tomographic Compton imaging is currently studied to establish a PG image and verify the treatment. However the quality of the reconstructed images depends on a number of factors such as the volume attenuation, the spatial and energy resolutions of the detectors, incomplete absorptions of high energy photons and noise from other particles reaching the camera. The impact of all these factors was not assessed in details. In this paper we investigate the influence of the PG energy spectrum on the reconstructed images. To this aim, we describe the process from the Monte Carlo simulation of the proton irradiation, through the Compton imaging of the PG distribution, up to the image reconstruction with a statistical MLEM method. We identify specific PG energy windows that are more relevant to detect discrepancies with the treatment plan. We find that for the simulated Compton device, the incomplete absorption of the photons with energy above about 2 MeV prevents the observation of the PG distributions at specific energies. It also leads to blurred images and smooths the distal slope of the 1D PG profiles obtained as projections on the central beam axis. We show that a selection of the events produced by γ photons having deposited almost all their energy in the camera allows to largely improve the images, a result that emphasizes the importance of the choice of the detector. However, this initial-energy-based selection is not accessible in practice. We then propose a method to estimate the range of the PG profile both for specific deposited-energy windows and for the full spectrum emission. The method relies on two parameters. We use a learning approach for their estimation and we show that it allows to detect few millimeter shifts of the PG profiles. PMID:27008459

  3. Fast proton spectroscopic imaging using steady-state free precession methods.

    PubMed

    Dreher, Wolfgang; Geppert, Christian; Althaus, Matthias; Leibfritz, Dieter

    2003-09-01

    Various pulse sequences for fast proton spectroscopic imaging (SI) using the steady-state free precession (SSFP) condition are proposed. The sequences use either only the FID-like signal S(1), only the echo-like signal S(2), or both signals in separate but adjacent acquisition windows. As in SSFP imaging, S(1) and S(2) are separated by spoiler gradients. RF excitation is performed by slice-selective or chemical shift-selective pulses. The signals are detected in absence of a B(0) gradient. Spatial localization is achieved by phase-encoding gradients which are applied prior to and rewound after each signal acquisition. Measurements with 2D or 3D spatial resolution were performed at 4.7 T on phantoms and healthy rat brain in vivo allowing the detection of uncoupled and J-coupled spins. The main advantages of SSFP based SI are the short minimum total measurement time (T(min)) and the high signal-to-noise ratio per unit measurement time (SNR(t)). The methods are of particular interest at higher magnetic field strength B(0), as TR can be reduced with increasing B(0) leading to a reduced T(min) and an increased SNR(t). Drawbacks consist of the limited spectral resolution, particularly at lower B(0), and the dependence of the signal intensities on T(1) and T(2). Further improvements are discussed including optimized data processing and signal detection under oscillating B(0) gradients leading to a further reduction in T(min). PMID:12939751

  4. Design and evaluation of a radio frequency coil for nuclear magnetic resonance imaging of fluorine and protons.

    PubMed

    Joseph, P M; Fishman, J E

    1985-01-01

    A frequency-switchable, homogeneous-field rf saddle coil has been designed for imaging both protons (1H, 59.1 MHz) and fluorine (19F, 55.6 MHz) on a 1.4-T superconducting small-bore nuclear magnetic resonance imager. Frequency and impedance switching is accomplished by external capacitance and cable length changes; these operations permit imaging of both nuclei without perturbing the sample. The coil is optimized for 19F operation, yet performs better at the proton frequency than does the unswitched 19F coil. The angular distribution of the coil's wires and the use of distributed capacitors are designed to optimize field homogeneity and Q. A quantitative image of field homogeneity is presented. The coil is suitable for imaging small animals (7-cm-diam bore) and couples far better to small samples than does our standard receiver coil (15.2 cm in diameter). Images of phantoms and rats injected with a perfluorinated blood substitute are presented. PMID:4079857

  5. Long-term stability and mechanical characteristics of kV digital imaging system for proton radiotherapy

    SciTech Connect

    Zhu, Mingyao Botticello, Thomas; Lu, Hsiao-Ming; Winey, Brian

    2014-04-15

    Purpose: To quantitatively evaluate the long-term image panel positioning stability and gantry angle dependence for gantry-mounted kV imaging systems. Methods: For patient setup digital imaging systems in isocentric rotating proton beam delivery facilities, physical crosshairs are commonly inserted into the snout to define the kV x-ray beam isocenter. Utilizing an automatic detection algorithm, the authors analyzed the crosshair center positions in 2744 patient setup kV images acquired with the four imagers in two treatment rooms from January 2012 to January 2013. The crosshair position was used as a surrogate for imaging panel position, and its long-term stability at the four cardinal angles and the panel flex dependency on gantry angle was investigated. Results: The standard deviation of the panel position distributions was within 0.32 mm (with the range of variation less than 1.4 mm) in both the X-Z plane and Y direction. The mean panel inplane rotations were not more than 0.51 for the four panels at the cardinal angles, with standard deviations ?0.26. The panel position variations with gantry rotation due to gravity (flex) were within 4 mm, and were panel-specific. Conclusions: The authors demonstrated that the kV image panel positions in our proton treatment system were highly reproducible at the cardinal angles over 13 months and also that the panel positions can be correlated to gantry angles. This result indicates that the kV image panel positions are stable over time; the amount of panel sag is predictable during gantry rotation and the physical crosshair for kV imaging may eventually be removed, with the imaging beam isocenter position routinely verified by adequate quality assurance procedures and measurements.

  6. Measurements of electron and proton heating temperatures from extreme-ultraviolet light images at 68 eV in petawatt laser experiments

    SciTech Connect

    Gu Peimin; Zhang, B.; Key, M. H.; Hatchett, S. P.; Barbee, T.; Freeman, R. R.; Akli, K.; Hey, D.; King, J. A.; Mackinnon, A. J.; Snavely, R. A.; Stephens, R. B.

    2006-11-15

    A 68 eV extreme-ultraviolet light imaging diagnostic measures short pulse isochoric heating by electrons and protons in petawatt laser experiments. Temperatures are deduced from the absolute intensities and comparison with modeling using a radiation hydrodynamics code.

  7. SU-E-J-213: Imaging and Treatment Isocenter Verification of a Gantry Mounted Proton Therapy System

    SciTech Connect

    Price, S; Goddu, S; Rankine, L; Klein, E

    2014-06-01

    Purpose: The Mevion proton therapy machine is the first to feature a gantry mounted sychro-cyclotron. In addition, the system utilizes a 6D motion couch and kV imaging for precise proton therapy. To quantify coincidence between these systems, isocentricity tests were performed based on kV imaging alignment using radiochromic film. Methods: The 100 ton gantry and 6D robotic couch can rotate 190 around isocenter to provide necessary beam angles for treatment. The kV sources and detector panels are deployed as needed to acquire orthogonal portals. Gantry and couch mechanical isocenter were tested using star-shots and radiochromic-film (RCF). Using kV imaging, the star-shot phantom was aligned to an embedded fiducial and the isocenter was marked on RCF with a pinprick. The couch and gantry stars were performed by irradiating films at every 45 and 30, respectively. A proton beam with a range and modulation-width of 18 cm was used. A Winston-Lutz test was also performed at the same gantry and couch rotations using a custom jig holding RCF and a tungsten ball placed at isocenter. A 2 cm diameter circular aperture was used for the irradiation. Results: The couch star-shot indicated a minimum tangent circle of 0.6 mm, with a 0.9 mm offset from the manually marked isocenter. The gantry star-shot showed a 0.6 mm minimum tangent circle with a 0.5 mm offset from the pinprick. The Winston Lutz test performed for gantry rotation showed a maximum deviation from center of 0.5 mm. Conclusion: Based on star-shots and Winston-Lutz tests, the proton gantry and 6D couch isocentricity are within 1 mm. In this study, we have shown that the methods commonly utilized for Linac characterization can be applied to proton therapy. This revolutionary proton therapy system possesses excellent agreement between the mechanical and radiation isocenter, providing highly precise treatment.

  8. Feasibility study of the neutron dose for real-time image-guided proton therapy: A Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Kim, Jin Sung; Shin, Jung Suk; Kim, Daehyun; Shin, Eunhyuk; Chung, Kwangzoo; Cho, Sungkoo; Ahn, Sung Hwan; Ju, Sanggyu; Chung, Yoonsun; Jung, Sang Hoon; Han, Youngyih

    2015-07-01

    Two full rotating gantries with different nozzles (multipurpose nozzle with MLC, scanning dedicated nozzle) for a conventional cyclotron system are installed and being commissioned for various proton treatment options at Samsung Medical Center in Korea. The purpose of this study is to use Monte Carlo simulation to investigate the neutron dose equivalent per therapeutic dose, H/D, for X-ray imaging equipment under various treatment conditions. At first, we investigated the H/D for various modifications of the beamline devices (scattering, scanning, multi-leaf collimator, aperture, compensator) at the isocenter and at 20, 40 and 60 cm distances from the isocenter, and we compared our results with those of other research groups. Next, we investigated the neutron dose at the X-ray equipment used for real-time imaging under various treatment conditions. Our investigation showed doses of 0.07 ~ 0.19 mSv/Gy at the X-ray imaging equipment, depending on the treatment option and interestingly, the 50% neutron dose reduction was observed due to multileaf collimator during proton scanning treatment with the multipurpose nozzle. In future studies, we plan to measure the neutron dose experimentally and to validate the simulation data for X-ray imaging equipment for use as an additional neutron dose reduction method.

  9. Proton Radiography

    NASA Astrophysics Data System (ADS)

    Morris, Christopher L.

    1998-04-01

    Although proton radiography has been studied in the past as an alternative to X-rays, relatively poor position resolution and expense have counterbalanced the dose advantage of protons. More recently we have shown that many of the advantages of protons as a radiographic probe can be realized by using a magnetic lens to focus the transmitted proton beam. Some potential advantages of protons over conventional X-ray techniques for flash radiography of thick, dense, dynamic systems include: 1) high penetrating power, 2) high detection efficiency, 3) small scattered background, 4) no need for a conversion target and the consequent phase space broadening of the beam, 5) inherent multi-pulse capability, and 6) large stand-off distances from the test object and containment vessel to the detectors. Additionally, the use of magnetic lens with thin detectors allows multiple images on a single axis though progressively smaller apertures to be used to vary the magnitude and Z-dependence of the interaction and can provide material identification. I will present data from experiments performed at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory and at the LANSCE accelerator at Los Alamos National Laboratory aimed at demonstrating proton radiography with a high-energy proton beams.

  10. Application of flat panel digital imaging for improvement of ocular melanoma patient set-up in proton beam therapy

    NASA Astrophysics Data System (ADS)

    Daftari, Inder K.; Essert, Timothy; Phillips, Theodore L.

    2009-01-01

    In order to reduce the dose to surrounding critical tissues and also minimize the probability of recurrence of the tumor the placement of radiation fields relative to patient anatomy is very essential in proton beam therapy of ocular tumors. To achieve this objective, patient setup and field placement have been verified before treatment by analyzing the portal images obtained with Polaroid film-camera system. The Polaroid films are becoming expensive and obsolete, making new methods of verifying the patient treatment position essential. The objective of this study was to implement an orthogonal flat panel digital imaging (FPDI) system as a tool to image-guided radiation therapy (IGRT) on the UC Davis cyclotron proton beam therapy line and to use the system for patient setup verification. The image quality of the system is sufficient to see an air hole with a diameter of 0.5 mm at a depth of 9 mm, in a 10 cm Lucite phantom. The subject contrast of the FPDI system varied from 16% to 29% by varying the size of the air hole in the phantom from 1 to 5 mm and changing the depth from 9 to 15 mm. The subject contrast for 0.5 mm air hole was 11%. The comparison of the setup variations as measured from Polaroid port films and FPDI was 0.10.7 mm in the X-direction, 0.20.2 mm in the Y-direction and 0.040.1 mm in Z-direction, respectively. The day-to-day positional variations in-patient set-ups were studied for 30 patients using the FPDI system. The patient position set-up on first day of treatment [defined by the X, Y, Z coordinates of the chair and head holder] was registered as the reference image. The comparison of day-to-day patient position with reference image indicated net translation along the three orthogonal axes as 0.31.88 mm in right-left direction, -0.31.78 in superior-inferior direction and -0.62.8 mm in anterior-posterior direction. The image quality of the FPDI system was sufficient to clearly reveal the radio-opaque markers on the digital image. In conclusion a FPDI system can accurately replace the Polaroid system and will facilitate daily portal alignment and true electronic IGRT verification of patient position and tumor location relative to the proton beam.

  11. Global auroral proton precipitation observed by IMAGE-FUV: Noon and midnight brightness dependence on solar wind characteristics and IMF orientation

    NASA Astrophysics Data System (ADS)

    Coumans, ValRie; GRard, Jean-Claude; Hubert, BenoT.; Meurant, Matthieu

    2006-05-01

    The brightness of proton aurora observed near solar maximum at summer and winter solstices with the FUV-SI12 global imager on board the IMAGE satellite has been correlated with the solar wind and the interplanetary magnetic field characteristics measured by ACE satellite instruments. By contrast to the electron aurora, we find a strong correlation both on nightside and dayside between the proton precipitated power and the solar wind dynamic pressure calculated with 1-hour averaged solar wind data. For both southward and northward IMF, the proton power increases with ?Bz?, but much more rapidly on the nightside for southward IMF orientation. Correlations for the nightside aurora were also calculated with a series of solar wind-magnetosphere coupling functions. We find highest correlation coefficients for expressions containing the dynamic pressure or involving the solar wind electric field in the Y-Z plane. The influence of the solar wind dynamic pressure on the proton aurora is tentatively explained by the effect of the pressure on the shape of the magnetosphere, generating stretching of the magnetotail and proton precipitation but also by other coupling processes between the solar wind and the magnetosphere. Adding FUV-WIC and SI13 electron aurora images in the study, we determine how proton and electron precipitations simultaneously react to solar wind and IMF characteristics and Kp. Results shows that protons are more reactive to dynamic pressure variations than electrons when Bz is positive, while the influence on of both types of particles is similar for negative Bz. The precipitating proton flux is found proportionally larger compared with the electron flux when the total auroral flux increases for low activity level. Instead, for high activity level, the proportion of the proton and the electron powers are similar when auroral power increases. Consequently, it is suggested that similar mechanisms cause proton and electron auroral precipitation for high activity levels, while they appear somewhat decoupled for lower activity conditions.

  12. Online image guided tumour tracking with scanned proton beams: a comprehensive simulation study

    NASA Astrophysics Data System (ADS)

    Zhang, Ye; Knopf, A.; Tanner, C.; Lomax, A. J.

    2014-12-01

    Tumour tracking with scanned particle beams potentially requires accurate 3D information on both tumour motion and related density variations. We have previously developed a model-based motion reconstruction method, which allows for the prediction of deformable motions from sparsely sampled surrogate motions tracked via an on-board imaging system (Zhang et al (2013 Phys. Med. Biol. 58 8621)). Here, we investigate the potential effectiveness of tumour tracking for scanned proton beam therapy using such an approach to guide scanned beam tracking, together with the effectiveness of ‘re-tracking’ for reducing residual motion effects due to tracking uncertainties. Three different beam tracking strategies (2D, 2D deformable and 3D) have been applied to three different liver motion cases, with mean magnitudes ranging from 10-20 mm. All simulations have been performed using simulated 4DCTs derived from 4DMRI datasets, whereby inter-breath-cycle motion variability is taken into account. The results show that, without beam tracking, large interplay effects are observed for all motion cases, resulting in CTV D5-95 values of 34.9/58.5/79.4% for the three cases, respectively. These can be reduced to 16.9/18.8/29.1% with 2D tracking, to 15.5/17.9/23.3% with 2D deformable tracking and to 15.1/17.8/21.0% with 3D tracking. Clear ‘inverse interplay’ effects have also been observed in the proximal portion of the field. However, with three-times re-tracking, D5-95 for the largest motions (20 mm) can be reduced to 13.0/12.8% for 2D and 3D tracking, respectively, and ‘hot spots’ resulting from the ‘inverse interplay’ effect can be substantially reduced. In summary, we have found that, for motions over 10 mm, tracking alone cannot fully mitigate motion effects, and can lead to substantially increased doses to normal tissues in the entrance path of the field. However, three-times re-tracking substantially improves the effectiveness of all types of beam tracking, with substantial advantages of 3D over 2D re-tracking only being observed for the largest motion scenario investigated.

  13. WE-E-BRF-01: The ESTRO-AAPM Joint Symposium On Imaging for Proton Treatment Planning and Guidance

    SciTech Connect

    Parodi, K; Dauvergne, D; Kruse, J

    2014-06-15

    In this first inaugural joint ESTRO-AAPM session we will attempt to provide some answers to the problems encountered in the clinical application of particle therapy. Indeed the main advantage is that the physical properties of ion beams offer high ballistic accuracy for tightly conformal irradiation of the tumour volume, with excellent sparing of surrounding healthy tissue and critical organs, This also its Achilles' heel calling for an increasing role of imaging to ensure safe application of the intended dose to the targeted area during the entire course of fractionated therapy. We have three distinguished speakers addressing possible solutions. Katia Parodi (Ludwig Maximilians University, Munich, Germany) To date, Positron Emission Tomography (PET) is the only technique which has been already clinically investigated for in-vivo visualization of the beam range during or shortly after ion beam delivery. The method exploits the transient amount of ?{sup 2}-activity induced in nuclear interactions between the primary beam and the irradiated tissue, depending on the ion beam species, the tissue elemental composition and physiological properties (in terms of biological clearance), as well as the time course of irradiation and imaging. This contribution will review initial results, ongoing methodological developments and remaining challenges related to the clinical usage of viable but often suboptimal instrumentation and workflows of PET-based treatment verification. Moreover, it will present and discuss promising new detector developments towards next-generation dedicated PET scanners relying on full-ring or dual-head designs for in-beam quasi real-time imaging. Denis Dauvergne (Institut de Physique Nucleaire de Lyon, Lyon, France) Prompt gamma radiation monitoring of hadron therapy presents the advantage of real time capability to measure the ion range. Both simulations and experiments show that millimetric verification of the range can be achieved at the pencil beam scale for active proton beam delivery in homogenous targets. The development of gamma cameras, that has been studied by several groups worldwide over the last years, now reaches - for some of them - the stage of being applicable in clinical conditions, with real size prototypes and count rate capability matching the therapeutic beam intensities. We will review the different concepts of gamma cameras, the advantages and limitations of this method, and the main challenges that should still be overcome before the widespread of prompt gamma quality assurance for proton and hadrontherapy. Jon Kruse (Mayo Clinic, Rochester, MN, USA) Treatment simulation images for proton therapy are used to determine proton stopping power and range in the patient. This talk will discuss the careful control of CT numbers and conversion of CT number to stopping power required in proton therapy. Imaging for treatment guidance of proton therapy also presents unique challenges which will be addressed. Among them are the enhanced relationship between internal anatomy changes and dosimetry, the need for imaging to support adaptive planning protocols, and high operational efficiency. Learning Objectives: To learn about the possibilities of using activation products to determine the range of particle beams in a patient treatment setting To be informed on an alternative methodology using prompt gamma detectors To understand the impact of the accuracy of the knowledge of the patient information with respect to the delivered treatment.

  14. Imaging of Amide Proton Transfer and Nuclear Overhauser Enhancement in Ischemic Stroke with Corrections for Competing Effects

    PubMed Central

    Li, Hua; Zu, Zhongliang; Zaiss, Moritz; Khan, Imad S.; Singer, Robert; Gochberg, Daniel F.; Bachert, Peter; Gore, John C.; Xu, Junzhong

    2015-01-01

    Chemical exchange saturation transfer (CEST) potentially provides the ability to detect small solute pools through indirect measurements of attenuated water signals. However, CEST effects may be diluted by various competing effects such as non-specific magnetization transfer (MT) and asymmetric MT effects, water longitudinal relaxation (T1), and direct water saturation (RF spillover). In the current study, CEST images were acquired in rats following ischemic stroke and analyzed by comparing the reciprocals of the CEST signals at three different saturation offsets. This combined approach corrects the above competing effects and provides a more robust signal metric sensitive specifically to proton exchange rate constant. The corrected amide proton transfer (APT) data show greater differences between the ischemic and the contralateral (non-ischemic) hemispheres. By contrast, corrected nuclear Overhauser enhancements (NOEs) around ?3.5 ppm from water change over time in both hemispheres, indicating whole-brain changes that have not been reported before. This study may help better understand the contrast mechanisms of APT and NOE imaging in ischemic stroke, and also establishes a framework for future stroke measurements using CEST imaging with spillover-, MT- and T1-corrections. PMID:25483870

  15. Imaging the proton via hard exclusive production in diffractive pp scattering

    SciTech Connect

    Charles Hyde; Leonid Frankfurt; Mark Strikman; Christian Weiss

    2007-05-21

    We discuss the prospects for probing Generalized Parton Distributions (GPDs) via exclusive production of a high-mass system (H = heavy quarkonium, di-photon, di-jet, Higgs boson) in diffractive pp scattering, pp -> p + H + p. In such processes the interplay of hard and soft interactions gives rise to a diffraction pattern in the final-state proton transverse momenta, which is sensitive to the transverse spatial distribution of partons in the colliding protons. We comment on the plans for diffractive pp measurements at RHIC and LHC. Such studies could complement future measurements of GPDs in hard exclusive ep scattering (JLab, COMPASS, EIC).

  16. Use of cross-linked hydrogel materials as image contrast agents in proton nuclear magnetic resonance tomography and tissue phantom kits containing such materials

    SciTech Connect

    Becall, P.T.

    1988-03-08

    This patent describes a method of contrasting a proton NMR tomograph of the gastro-intestinal tract, or a portion thereof, by administering enterally to a mammal an effective image contrasting amount of a physiologically tolerable, synthetic, substantially nondegradable cross-linked hydrogel having, in the aqueous swollen state, spin-lattice or spin-spin relaxation values substantially shorter than the surrounding gastro-intestinal tissue environment; and subjecting the mammal to the proton NMR tomography.

  17. Various ligand-coated ultrasmall gadolinium-oxide nanoparticles: Water proton relaxivity and in-vivo T1 MR image

    NASA Astrophysics Data System (ADS)

    Park, Ja Young; Kim, Sung June; Lee, Gang Ho; Jin, Seonguk; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok

    2015-04-01

    Surface coating of nanoparticles with ligands is essential in magnetic resonance imaging (MRI) because of solubility in water and biocompatibility. In this study, five organic molecules were used for surface coating of ultrasmall gadolinium-oxide (Gd2O3) nanoparticles (d avg = 2.0 nm). All of the samples showed large longitudinal (r1) and transverse (r2) water proton relaxivities with r2/r1 ratios that were close to one, corresponding to ideal conditions for T1 MRI contrast agents. Finally, in-vivo T1 MR images were acquired to prove the effectiveness of the surface-coated ultrasmall Gd2O3 nanoparticles as a T1 MRI contrast agent.

  18. VARIABLE FIELD PROTON-ELECTRON DOUBLE-RESONANCE IMAGING: APPLICATION TO pH-MAPPING OF AQUEOUS SAMPLES

    PubMed Central

    Khramtsov, Valery V.; Caia, George L.; Shet, Keerthi; Kesselring, Eric; Petryakov, Sergey; Zweier, Jay L.; Samouilov, Alexandre

    2009-01-01

    A new concept of Variable Field Proton-Electron Double-Resonance Imaging (VF PEDRI) is proposed. This allows for functional mapping using specifically designed paramagnetic probes (e.g. oxygen or pH mapping) with MRI high quality spatial resolution and short acquisition time. Studies performed at 200 G field MRI with phantoms show that a pH map of the sample can be extracted using only two PEDRI images acquired in 140 s at pre-selected EPR excitation fields providing pH resolution of 0.1 pH units and a spatial resolution of 1.25 mm. Note that while concept of functional VF PEDRI was demonstrated using the pH probe, it can be applied for studies of other biologically relevant parameters of the medium such as redox state, concentrations of oxygen or glutathione using specifically designed EPR probes. PMID:20007019

  19. Two-exponential analysis of spin-spin proton relaxation times in MR imaging using surface coils

    SciTech Connect

    Schad, L.R.; Brix, G.; Semmler, W.; Gueckel, F.L.; Lorenz, W.J. )

    1989-07-01

    Proton relaxation time measurements were performed on a standard whole body MR imager operating at 1.5 T using a conventional surface coil of the manufacturer. A combined CP/CPMG multiecho, multislice sequence was used for the T1 and T2 relaxation time measurements. Two repetition times of 2000 ms (30 echoes) and 600 ms (2 echoes) with 180 degrees-pulse intervals of 2 tau = 22 ms were interleaved in this sequence. A two-exponential T2 analysis of each pixel of the spin-echo images was computed in a case of an acoustic neurinoma. The two-exponential images show a short component (T2S) due to white and gray matter and a long component (T2S) due to the cerebrospinal fluid. In the fatty tissue two components with T2S = 35 {plus minus} 3 ms and T2L = 164 {plus minus} 7 ms were measured. Comparing with Gd-DTPA imaging the relaxation time images show a clear differentiation of vital tumor tissue and cerebrospinal fluid.

  20. Effect of the saturation pulse duration on chemical exchange saturation transfer in amide proton transfer MR imaging: a phantom study.

    PubMed

    Wada, Tatsuhiro; Togao, Osamu; Tokunaga, Chiaki; Funatsu, Ryouhei; Kobayashi, Kouji; Nakamura, Yasuhiko

    2016-01-01

    Amide proton transfer (APT) contrast imaging is based on the chemical exchange saturation transfer (CEST) of protons between the amide groups and bulk water. Here, we demonstrate the effect of the saturation pulse duration on CEST in APT imaging with use of a clinical MR scanner. Four samples were prepared from chicken egg white diluted with H2O. Experiments were performed on a 3T clinical MR scanner with use of a body coil for two-channel parallel radiofrequency transmission. APT images were acquired at six frequency offsets (± 3.0, ± 3.5, ± 4.0 ppm) with respect to the water resonance as well as one far off-resonant frequency (-160 ppm) for signal normalization. The CEST effect was defined as asymmetry of the magnetization transfer ratio at 3.5 ppm. We measured the CEST effects in the egg white samples with different concentrations at seven saturation pulse durations. The influence of the extension of repetition time (TR) on the CEST effect was also evaluated. The CEST effect was not influenced by the change in TR. The CEST effect was increased significantly with the concentration when the duration was ≥1.0 s (P < 0.01). The CEST effect was highly correlated with the concentration at all saturation pulse durations, and its increase ratio was higher at longer saturation pulse durations. In conclusion, a long saturation pulse duration is useful for the sensitive detection of mobile proteins and peptides in APT imaging. PMID:26099607

  1. Variable Radio Frequency Proton-Electron Double-Resonance Imaging: Application to pH Mapping of Aqueous Samples

    PubMed Central

    Efimova, Olga V.; Sun, Ziqi; Petryakov, Sergey; Kesselring, Eric; Caia, George L.; Johnson, David; Zweier, Jay L.; Khramtsov, Valery V.; Samouilov, Alexandre

    2011-01-01

    Proton-Electron Double-Resonance Imaging (PEDRI) offers rapid image data collection and high resolution for spatial distribution of paramagnetic probes. Recently we developed the concept of Variable Field (VF) PEDRI which enables extracting a functional map from a limited number of images acquired at pre-selected EPR excitation fields using specific paramagnetic probes (Khramtsov et al. 2010, JMR, 202, 267-273). In this work, we propose and evaluate a new modality of PEDRI-based functional imaging with enhanced temporal resolution which we term Variable Radio Frequency (VRF) PEDRI. The approach allows for functional mapping (e.g., pH mapping) using specifically designed paramagnetic probes with high quality spatial resolution and short acquisition times. This approach uses a stationary magnetic field but different EPR RFs. The ratio of Overhauser enhancements measured at each pixel at two different excitation frequencies corresponding to the resonances of protonated and deprotonated forms of a pH-sensitive nitroxide is converted to a pH map using a corresponding calibration curve. Elimination of field cycling decreased the acquisition time by exclusion periods of ramping and stabilization of the magnetic field. Improved magnetic field homogeneity and stability allowed for the fast MRI acquisition modalities such as fast spin echo. In total, about 30-fold decrease in EPR irradiation time was achieved for VRF PEDRI (2.4 s) compared with VF PEDRI (70 s). This is particularly important for in vivo applications enabling one to overcome the limiting stability of paramagnetic probes and sample overheating by reducing RF power deposition. PMID:21320790

  2. Proton radiography to improve proton therapy treatment

    NASA Astrophysics Data System (ADS)

    Takatsu, J.; van der Graaf, E. R.; Van Goethem, M.-J.; van Beuzekom, M.; Klaver, T.; Visser, J.; Brandenburg, S.; Biegun, A. K.

    2016-01-01

    The quality of cancer treatment with protons critically depends on an accurate prediction of the proton stopping powers for the tissues traversed by the protons. Today, treatment planning in proton radiotherapy is based on stopping power calculations from densities of X-ray Computed Tomography (CT) images. This causes systematic uncertainties in the calculated proton range in a patient of typically 3–4%, but can become even 10% in bone regions [1,2,3,4,5,6,7,8]. This may lead to no dose in parts of the tumor and too high dose in healthy tissues [1]. A direct measurement of proton stopping powers with high-energy protons will allow reducing these uncertainties and will improve the quality of the treatment. Several studies have shown that a sufficiently accurate radiograph can be obtained by tracking individual protons traversing a phantom (patient) [4,6,10]. Our studies benefit from the gas-filled time projection chambers based on GridPix technology [2], developed at Nikhef, capable of tracking a single proton. A BaF2 crystal measuring the residual energy of protons was used. Proton radiographs of phantom consisting of different tissue-like materials were measured with a 30×30 mm2 150 MeV proton beam. Measurements were simulated with the Geant4 toolkit.First experimental and simulated energy radiographs are in very good agreement [3]. In this paper we focus on simulation studies of the proton scattering angle as it affects the position resolution of the proton energy loss radiograph. By selecting protons with a small scattering angle, the image quality can be improved significantly.

  3. Calibration of CT Hounsfield units for proton therapy treatment planning: use of kilovoltage and megavoltage images and comparison of parameterized methods

    NASA Astrophysics Data System (ADS)

    De Marzi, L.; Lesven, C.; Ferrand, R.; Sage, J.; Boul, T.; Mazal, A.

    2013-06-01

    Proton beam range is of major concern, in particular, when images used for dose computations are artifacted (for example in patients with surgically treated bone tumors). We investigated several conditions and methods for determination of computed tomography Hounsfield unit (CT-HU) calibration curves, using two different conversion schemes. A stoichiometric methodology was used on either kilovoltage (kV) or megavoltage (MV) CT images and the accuracy of the calibration methods was evaluated. We then studied the effects of metal artifacts on proton dose distributions using metallic implants in rigid phantom mimicking clinical conditions. MV-CT images were used to evaluate relative proton stopping power in certain high density implants, and a methodology is proposed for accurate delineation and dose calculation, using a combined set of kV- and MV-CT images. Our results show good agreement between measurements and dose calculations or relative proton stopping power determination (<5%). The results also show that range uncertainty increases when only kV-CT images are used or when no correction is made on artifacted images. However, differences between treatment plans calculated on corrected kV-CT data and MV-CT data remained insignificant in the investigated patient case, even with streak artifacts and volume effects that reduce the accuracy of manual corrections.

  4. Imaging of prompt gamma rays emitted during delivery of clinical proton beams with a Compton camera: feasibility studies for range verification

    NASA Astrophysics Data System (ADS)

    Polf, Jerimy C.; Avery, Stephen; Mackin, Dennis S.; Beddar, Sam

    2015-09-01

    The purpose of this paper is to evaluate the ability of a prototype Compton camera (CC) to measure prompt gamma rays (PG) emitted during delivery of clinical proton pencil beams for prompt gamma imaging (PGI) as a means of providing in vivo verification of the delivered proton radiotherapy beams. A water phantom was irradiated with clinical 114 MeV and 150 MeV proton pencil beams. Up to 500 cGy of dose was delivered per irradiation using clinical beam currents. The prototype CC was placed 15?cm from the beam central axis and PGs from 0.2 MeV up to 6.5 MeV were measured during irradiation. From the measured data (2D) images of the PG emission were reconstructed. (1D) profiles were extracted from the PG images and compared to measured depth dose curves of the delivered proton pencil beams. The CC was able to measure PG emission during delivery of both 114 MeV and 150 MeV proton beams at clinical beam currents. 2D images of the PG emission were reconstructed for single 150 MeV proton pencil beams as well as for a 5??????5?cm mono-energetic layer of 114 MeV pencil beams. Shifts in the Bragg peak (BP) range were detectable on the 2D images. 1D profiles extracted from the PG images show that the distal falloff of the PG emission profile lined up well with the distal BP falloff. Shifts as small as 3?mm in the beam range could be detected from the 1D PG profiles with an accuracy of 1.5?mm or better. However, with the current CC prototype, a dose of 400 cGy was required to acquire adequate PG signal for 2D PG image reconstruction. It was possible to measure PG interactions with our prototype CC during delivery of proton pencil beams at clinical dose rates. Images of the PG emission could be reconstructed and shifts in the BP range were detectable. Therefore PGI with a CC for in vivo range verification during proton treatment delivery is feasible. However, improvements in the prototype CC detection efficiency and reconstruction algorithms are necessary to make it a clinically viable PGI system.

  5. Imaging Changes in Pediatric Intracranial Ependymoma Patients Treated With Proton Beam Radiation Therapy Compared to Intensity Modulated Radiation Therapy

    SciTech Connect

    Gunther, Jillian R.; Sato, Mariko; Chintagumpala, Murali; Ketonen, Leena; Jones, Jeremy Y.; Allen, Pamela K.; Paulino, Arnold C.; Okcu, M. Fatih; Su, Jack M.; Weinberg, Jeffrey; Boehling, Nicholas S.; Khatua, Soumen; Adesina, Adekunle; Dauser, Robert; Whitehead, William E.; Mahajan, Anita

    2015-09-01

    Purpose: The clinical significance of magnetic resonance imaging (MRI) changes after radiation therapy (RT) in children with ependymoma is not well defined. We compared imaging changes following proton beam radiation therapy (PBRT) to those after photon-based intensity modulated RT (IMRT). Methods and Materials: Seventy-two patients with nonmetastatic intracranial ependymoma who received postoperative RT (37 PBRT, 35 IMRT) were analyzed retrospectively. MRI images were reviewed by 2 neuroradiologists. Results: Sixteen PBRT patients (43%) developed postradiation MRI changes at 3.8 months (median) with resolution by 6.1 months. Six IMRT patients (17%) developed changes at 5.3 months (median) with 8.3 months to resolution. Mean age at radiation was 4.4 and 6.9 years for PBRT and IMRT, respectively (P=.06). Age at diagnosis (>3 years) and time of radiation (≥3 years) was associated with fewer imaging changes on univariate analysis (odds ratio [OR]: 0.35, P=.048; OR: 0.36, P=.05). PBRT (compared to IMRT) was associated with more frequent imaging changes, both on univariate (OR: 3.68, P=.019) and multivariate (OR: 3.89, P=.024) analyses. Seven (3 IMRT, 4 PBRT) of 22 patients with changes had symptoms requiring intervention. Most patients were treated with steroids; some PBRT patients also received bevacizumab and hyperbaric oxygen therapy. None of the IMRT patients had lasting deficits, but 2 patients died from recurrent disease. Three PBRT patients had persistent neurological deficits, and 1 child died secondarily to complications from radiation necrosis. Conclusions: Postradiation MRI changes are more common with PBRT and in patients less than 3 years of age at diagnosis and treatment. It is difficult to predict causes for development of imaging changes that progress to clinical significance. These changes are usually self-limiting, but some require medical intervention, especially those involving the brainstem.

  6. NOTE: Detection limits for ferrimagnetic particle concentrations using magnetic resonance imaging based proton transverse relaxation rate measurements

    NASA Astrophysics Data System (ADS)

    Pardoe, H.; Chua-anusorn, W.; St. Pierre, T. G.; Dobson, J.

    2003-03-01

    A clinical magnetic resonance imaging (MRI) system was used to measure proton transverse relaxation rates (R2) in agar gels with varying concentrations of ferrimagnetic iron oxide nanoparticles in a field strength of 1.5 T. The nanoparticles were prepared by coprecipitation of ferric and ferrous ions in the presence of either dextran or polyvinyl alcohol. The method of preparation resulted in loosely packed clusters (dextran) or branched chains (polyvinyl alcohol) of particles containing of the order of 600 and 400 particles, respectively. For both methods of particle preparation, concentrations of ferrimagnetic iron in agar gel less than 0.01 mg ml-1 had no measurable effect on the value of R2 for the gel. The results indicate that MRI-based R2 measurements using 1.5 T clinical scanners are not quite sensitive enough to detect the very low concentrations of nanoparticulate biogenic magnetite reported in human brain tissue.

  7. Bio-metals imaging and speciation in cells using proton and synchrotron radiation X-ray microspectroscopy

    PubMed Central

    Ortega, Richard; Devs, Guillaume; Carmona, Asuncin

    2009-01-01

    The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular chemical element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to chemical element analysis in subcellular compartments. The imaging and quantification of trace elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides chemical element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles. PMID:19605403

  8. Five-Year Outcomes from 3 Prospective Trials of Image-Guided Proton Therapy for Prostate Cancer

    SciTech Connect

    Mendenhall, Nancy P.; Hoppe, Bradford S.; Nichols, Romaine C.; Mendenhall, William M.; Morris, Christopher G.; Li, Zuofeng; Su, Zhong; Williams, Christopher R.; Costa, Joseph; Henderson, Randal H.

    2014-03-01

    Purpose: To report 5-year clinical outcomes of 3 prospective trials of image-guided proton therapy for prostate cancer. Methods and Materials: A total of 211 prostate cancer patients (89 low-risk, 82 intermediate-risk, and 40 high-risk) were treated in institutional review board-approved trials of 78 cobalt gray equivalent (CGE) in 39 fractions for low-risk disease, 78 to 82 CGE for intermediate-risk disease, and 78 CGE with concomitant docetaxel therapy followed by androgen deprivation therapy for high-risk disease. Toxicities were graded according to Common Terminology Criteria for Adverse Events (CTCAE), version 3.0. Median follow-up was 5.2 years. Results: Five-year rates of biochemical and clinical freedom from disease progression were 99%, 99%, and 76% in low-, intermediate-, and high-risk patients, respectively. Actuarial 5-year rates of late CTCAE, version 3.0 (or version 4.0) grade 3 gastrointestinal and urologic toxicity were 1.0% (0.5%) and 5.4% (1.0%), respectively. Median pretreatment scores and International Prostate Symptom Scores at >4 years posttreatment were 8 and 7, 6 and 6, and 9 and 8, respectively, among the low-, intermediate-, and high-risk patients. There were no significant changes between median pretreatment summary scores and Expanded Prostate Cancer Index Composite scores at >4 years for bowel, urinary irritative and/or obstructive, and urinary continence. Conclusions: Five-year clinical outcomes with image-guided proton therapy included extremely high efficacy, minimal physician-assessed toxicity, and excellent patient-reported outcomes. Further follow-up and a larger patient experience are necessary to confirm these favorable outcomes.

  9. SU-E-T-387: Achieving Optimal Patient Setup Imaging and Treatment Workflow Configurations in Multi-Room Proton Centers

    SciTech Connect

    Zhang, H; Prado, K; Langen, K; Yi, B; Mehta, M; Regine, W; D'Souza, W

    2014-06-01

    Purpose: To simulate patient flow in proton treatment center under uncertainty and to explore the feasibility of treatment preparation rooms to improve patient throughput and cyclotron utilization. Methods: Three center layout scenarios were modeled: (S1: In-Tx room imaging) patient setup and imaging (planar/volumetric) performed in treatment room, (S2: Patient setup in preparation room) each treatment room was assigned with preparation room(s) that was equipped with lasers only for patient setup and gross patient alignment, and (S3: Patient setup and imaging in preparation room) preparation room(s) was equipped with laser and volumetric imaging for patient setup, gross and fine patient alignment. A 'snap' imaging was performed in treatment room. For each scenario, the number of treatment rooms and the number of preparation rooms serving each treatment room were varied. We examined our results (average of 100 16-hour (two shifts) working days) by evaluating patient throughput and cyclotron utilization. Results: When the number of treatment rooms increased ([from, to]) [1, 5], daily patient throughput increased [32, 161], [29, 184] and [27, 184] and cyclotron utilization increased [13%, 85%], [12%, 98%], and [11%, 98%] for scenarios S1, S2 and S3 respectively. However, both measures plateaued after 4 rooms. With the preparation rooms, the throughput and the cyclotron utilization increased by 14% and 15%, respectively. Three preparation rooms were optimal to serve 1-3 treatment rooms and two preparation rooms were optimal to serve 4 or 5 treatment rooms. Conclusion: Patient preparation rooms for patient setup may increase throughput and decrease the need for additional treatment rooms (cost effective). Optimal number of preparation rooms serving each gantry room varies as a function of treatment rooms and patient setup scenarios. A 5th treatment room may not be justified by throughput or utilization.

  10. An imaging informatics-based system to support animal studies for treating pain in spinal cord injury utilizing proton-beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Verma, Sneha K.; Liu, Brent J.; Gridley, Daila S.; Mao, Xiao W.; Kotha, Nikhil

    2015-03-01

    In previous years we demonstrated an imaging informatics system designed to support multi-institutional research focused on the utilization of proton radiation for treating spinal cord injury (SCI)-related pain. This year we will demonstrate an update on the system with new modules added to perform image processing on evaluation data using immunhistochemistry methods to observe effects of proton therapy. The overarching goal of the research is to determine the effectiveness of using the proton beam for treating SCI-related neuropathic pain as an alternative to invasive surgical lesioning. The research is a joint collaboration between three major institutes, University of Southern California (data collection/integration and image analysis), Spinal Cord Institute VA Healthcare System, Long Beach (patient subject recruitment), and Loma Linda University and Medical Center (human and preclinical animal studies). The system that we are presenting is one of its kind which is capable of integrating a large range of data types, including text data, imaging data, DICOM objects from proton therapy treatment and pathological data. For multi-institutional studies, keeping data secure and integrated is very crucial. Different kinds of data within the study workflow are generated at different stages and different groups of people who process and analyze them in order to see hidden patterns within healthcare data from a broader perspective. The uniqueness of our system relies on the fact that it is platform independent and web-based which makes it very useful in such a large-scale study.

  11. A dual-tuned probe and multiband receiver front end for X-nucleus spectroscopy with proton scout imaging in vivo

    SciTech Connect

    Tropp, J.; Sugiura, S. )

    1989-09-01

    A dual-tuned volume coil probe and a novel multituned receiver front end are described, for spectroscopy in vivo of X nuclei with scout imaging of protons. Detailed circuit information is given for the probe, diplexer, receiver protection switch, and preamplifier.

  12. Investigating CT to CBCT image registration for head and neck proton therapy as a tool for daily dose recalculation

    SciTech Connect

    Landry, Guillaume; Nijhuis, Reinoud; Thieke, Christian; Reiner, Michael; Ganswindt, Ute; Belka, Claus; Dedes, George; Handrack, Josefine; Parodi, Katia; Janssens, Guillaume; Orban de Xivry, Jonathan; Kamp, Florian; Wilkens, Jan J.; Paganelli, Chiara; Riboldi, Marco; Baroni, Guido

    2015-03-15

    Purpose: Intensity modulated proton therapy (IMPT) of head and neck (H and N) cancer patients may be improved by plan adaptation. The decision to adapt the treatment plan based on a dose recalculation on the current anatomy requires a diagnostic quality computed tomography (CT) scan of the patient. As gantry-mounted cone beam CT (CBCT) scanners are currently being offered by vendors, they may offer daily or weekly updates of patient anatomy. CBCT image quality may not be sufficient for accurate proton dose calculation and it is likely necessary to perform CBCT CT number correction. In this work, the authors investigated deformable image registration (DIR) of the planning CT (pCT) to the CBCT to generate a virtual CT (vCT) to be used for proton dose recalculation. Methods: Datasets of six H and N cancer patients undergoing photon intensity modulated radiation therapy were used in this study to validate the vCT approach. Each dataset contained a CBCT acquired within 3 days of a replanning CT (rpCT), in addition to a pCT. The pCT and rpCT were delineated by a physician. A Morphons algorithm was employed in this work to perform DIR of the pCT to CBCT following a rigid registration of the two images. The contours from the pCT were deformed using the vector field resulting from DIR to yield a contoured vCT. The DIR accuracy was evaluated with a scale invariant feature transform (SIFT) algorithm comparing automatically identified matching features between vCT and CBCT. The rpCT was used as reference for evaluation of the vCT. The vCT and rpCT CT numbers were converted to stopping power ratio and the water equivalent thickness (WET) was calculated. IMPT dose distributions from treatment plans optimized on the pCT were recalculated with a Monte Carlo algorithm on the rpCT and vCT for comparison in terms of gamma index, dose volume histogram (DVH) statistics as well as proton range. The DIR generated contours on the vCT were compared to physician-drawn contours on the rpCT. Results: The DIR accuracy was better than 1.4 mm according to the SIFT evaluation. The mean WET differences between vCT (pCT) and rpCT were below 1 mm (2.6 mm). The amount of voxels passing 3%/3 mm gamma criteria were above 95% for the vCT vs rpCT. When using the rpCT contour set to derive DVH statistics from dose distributions calculated on the rpCT and vCT the differences, expressed in terms of 30 fractions of 2 Gy, were within [−4, 2 Gy] for parotid glands (D{sub mean}), spinal cord (D{sub 2%}), brainstem (D{sub 2%}), and CTV (D{sub 95%}). When using DIR generated contours for the vCT, those differences ranged within [−8, 11 Gy]. Conclusions: In this work, the authors generated CBCT based stopping power distributions using DIR of the pCT to a CBCT scan. DIR accuracy was below 1.4 mm as evaluated by the SIFT algorithm. Dose distributions calculated on the vCT agreed well to those calculated on the rpCT when using gamma index evaluation as well as DVH statistics based on the same contours. The use of DIR generated contours introduced variability in DVH statistics.

  13. Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters.

    PubMed

    Cambraia Lopes, Patricia; Clementel, Enrico; Crespo, Paulo; Henrotin, Sebastien; Huizenga, Jan; Janssens, Guillaume; Parodi, Katia; Prieels, Damien; Roellinghoff, Frauke; Smeets, Julien; Stichelbaut, Frederic; Schaart, Dennis R

    2015-08-01

    Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we present an initial performance test of two knife-edge slit camera prototypes based on arrays of digital photon counters (DPCs). PG profiles emitted from a PMMA target upon irradiation with a 160 MeV proton pencil beams (about 6.5 10(9) protons delivered in total) were measured using detector modules equipped with four DPC arrays coupled to BGO or LYSO : Ce crystal matrices. The knife-edge slit collimator and detector module were placed at 15 cm and 30 cm from the beam axis, respectively, in all cases. The use of LYSO : Ce enabled time-of-flight (TOF) rejection of background events, by synchronizing the DPC readout electronics with the 106 MHz radiofrequency signal of the cyclotron. The signal-to-background (S/B) ratio of 1.6 obtained with a 1.5 ns TOF window and a 3 MeV-7 MeV energy window was about 3 times higher than that obtained with the same detector module without TOF discrimination and 2 times higher than the S/B ratio obtained with the BGO module. Even 1 mm shifts of the Bragg peak position translated into clear and consistent shifts of the PG profile if TOF discrimination was applied, for a total number of protons as low as about 6.5 10(8) and a detector surface of 6.6 cm 6.6 cm. PMID:26216269

  14. Proton imaging of hohlraum plasma stagnation in inertial-confinement-fusion experiments

    NASA Astrophysics Data System (ADS)

    Li, C. K.; Sguin, F. H.; Frenje, J. A.; Sinenian, N.; Rosenberg, M. J.; Manuel, M. J.-E.; Rinderknecht, H. G.; Zylstra, A. B.; Petrasso, R. D.; Amendt, P. A.; Landen, O. L.; Mackinnon, A. J.; Town, R. P. J.; Wilks, S. C.; Betti, R.; Meyerhofer, D. D.; Soures, J. M.; Hund, J.; Kilkenny, J. D.; Nikroo, A.

    2013-07-01

    Proton radiography of the spatial structure and temporal evolution of plasma blowing off from a hohlraum wall reveals how the fill gas compresses the wall blow-off, inhibits plasma jet formation and impedes plasma stagnation in the hohlraum interior. The roles of spontaneously generated electric and magnetic fields in hohlraum dynamics and capsule implosions are demonstrated. The heat flux is shown to rapidly convect the magnetic field due to the Nernst effect, which is shown to be 10 times faster than convection by the plasma fluid from expanded wall blow-off (vN 10v). This leads to inhibition of heat transfer from the gas region in the laser beam paths to the surrounding cold gas, resulting in a local plasma temperature increase. The experiments show that interpenetration of the two materials (gas and wall) occurs due to the classical Rayleigh-Taylor instability as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blow-off. This experiment provides physics insight into the effects of fill gas on x-ray-driven implosions, and would impact the ongoing ignition experiments at the National Ignition Facility.

  15. An overview of alignment issues for in-vivo image guided proton therapy

    NASA Astrophysics Data System (ADS)

    Macq, Benoit; Orban de Xivry, Jonathan

    2015-01-01

    Protontherapy is based on physical properties of ion beams which allow the delivery of high radiation doses at very precise location in the body of the patient. The treatment planning aims at maximizing the delivery in the target volume while avoiding any organs at risk. The treatment is generally planned prior the treatment, and the patient is aligned in the treatment room on the basis of fiducial markers. However, the alignment of the patient may suffer from lack of precision and moreover, the body of the patient may vary between the time of imaging for planning and the time of treatment in the protontherapy room. More precise protontherapy and adaptive treatment which can track modifications of the body and the treatment of mobile tumors require the design of in vivo imaging systems to be deployed in the treatment room. The goal of this paper is to overview the present and future development of in-vivo image guided protontherapy and to give some image processing related challenges. The technique mostly used today is to take 2 orthogonal X-ray views of the patient. It requires an efficient 2D-3D coregistration procedure but is quite easy to deploy. Cone Beam CT is a next step which allows the capture of an in-vivo 3-D view on which the 3-D planning can be registered. The ultimate goal is to develop 4-D imaging techniques suited for the treatment of mobile tumors, for the cases of lung cancer. The development of new detectors will allow to validate the treatment by an "a posteriori" validation of the dose delivery in the body.

  16. In Vivo ProtonElectron Double-Resonance Imaging of Extracellular Tumor pH Using an Advanced Nitroxide Probe

    PubMed Central

    Samouilov, Alexandre; Efimova, Olga V.; Bobko, Andrey A.; Sun, Ziqi; Petryakov, Sergey; Eubank, Timothy D.; Trofimov, Dmitrii G.; Kirilyuk, Igor A.; Grigorev, Igor A.; Takahashi, Wataru; Zweier, Jay L.; Khramtsov, Valery V.

    2014-01-01

    A variable radio frequency protonelectron double-resonance imaging (VRF PEDRI) approach for pH mapping of aqueous samples has been recently developed (Efimova et al. J. Magn. Reson. 2011, 209, 227232). A pH map is extracted from two PEDRI acquisitions performed at electron paramagnetic resonance (EPR) frequencies of protonated and unprotonated forms of a pH-sensitive probe. To translate VRF PEDRI to an in vivo setting, an advanced pH probe was synthesized. Probe deuteration resulted in a narrow spectral line of 1.2 G compared to a nondeuterated analogue line width of 2.1 G allowing for an increase of Overhauser enhancements and reduction in rf power deposition. Binding of the probe to the cell-impermeable tripeptide, glutathione (GSH), allows for targeting to extracellular tissue space for monitoring extracellular tumor acidosis, a prognostic factor in tumor pathophysiology. The probe demonstrated pH sensitivity in the 5.87.8 range, optimum for measurement of acidic extracellular tumor pH (pHe). In vivo VRF PEDRI was performed on Met-1 tumor-bearing mice. Compared to normal mammary glands with a neutral mean pHe (7.1 0.1), we observed broader pH distribution with acidic mean pHe (6.8 0.1) in tumor tissue. In summary, VRF PEDRI in combination with a newly developed pH probe provides an analytical approach for spatially resolved noninvasive pHe monitoring, in vivo. PMID:24372284

  17. In vivo proton-electron double-resonance imaging of extracellular tumor pH using an advanced nitroxide probe.

    PubMed

    Samouilov, Alexandre; Efimova, Olga V; Bobko, Andrey A; Sun, Ziqi; Petryakov, Sergey; Eubank, Timothy D; Trofimov, Dmitrii G; Kirilyuk, Igor A; Grigor'ev, Igor A; Takahashi, Wataru; Zweier, Jay L; Khramtsov, Valery V

    2014-01-21

    A variable radio frequency proton-electron double-resonance imaging (VRF PEDRI) approach for pH mapping of aqueous samples has been recently developed (Efimova et al. J. Magn. Reson. 2011, 209, 227-232). A pH map is extracted from two PEDRI acquisitions performed at electron paramagnetic resonance (EPR) frequencies of protonated and unprotonated forms of a pH-sensitive probe. To translate VRF PEDRI to an in vivo setting, an advanced pH probe was synthesized. Probe deuteration resulted in a narrow spectral line of 1.2 G compared to a nondeuterated analogue line width of 2.1 G allowing for an increase of Overhauser enhancements and reduction in rf power deposition. Binding of the probe to the cell-impermeable tripeptide, glutathione (GSH), allows for targeting to extracellular tissue space for monitoring extracellular tumor acidosis, a prognostic factor in tumor pathophysiology. The probe demonstrated pH sensitivity in the 5.8-7.8 range, optimum for measurement of acidic extracellular tumor pH (pH(e)). In vivo VRF PEDRI was performed on Met-1 tumor-bearing mice. Compared to normal mammary glands with a neutral mean pH(e) (7.1 0.1), we observed broader pH distribution with acidic mean pH(e) (6.8 0.1) in tumor tissue. In summary, VRF PEDRI in combination with a newly developed pH probe provides an analytical approach for spatially resolved noninvasive pHe monitoring, in vivo. PMID:24372284

  18. Proton: The Particle

    SciTech Connect

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10{sup 80}. Protons were created at 10{sup −6} –1 second after the Big Bang at ≈1.37 × 10{sup 10} years beforethe present. Proton life span has been experimentally determined to be ≥10{sup 34} years; that is, the age of the universe is 10{sup −24}th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W{sup +}, W{sup −}, Z{sup 0}, and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter.

  19. Proton: the particle.

    PubMed

    Suit, Herman

    2013-11-01

    The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10(80). Protons were created at 10(-6) -1 second after the Big Bang at ≈1.37 × 10(10) years beforethe present. Proton life span has been experimentally determined to be ≥10(34) years; that is, the age of the universe is 10(-24)th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W(+), W(-), Z(0), and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter. PMID:24074929

  20. Proton radiography for clinical applications

    NASA Astrophysics Data System (ADS)

    Talamonti, C.; Reggioli, V.; Bruzzi, M.; Bucciolini, M.; Civinini, C.; Marrazzo, L.; Menichelli, D.; Pallotta, S.; Randazzo, N.; Sipala, V.; Cirrone, G. A. P.; Petterson, M.; Blumenkrantz, N.; Feldt, J.; Heimann, J.; Lucia, D.; Seiden, A.; Williams, D. C.; Sadrozinski, H. F.-W.; Bashkirov, V.; Schulte, R.

    2010-01-01

    Proton imaging is not yet applied as a clinical routine, although its advantages have been demonstrated. In the context of quality assurance in proton therapy, proton images can be used to verify the correct positioning of the patient and to control the range of protons. Proton computed tomography (pCT) is a 3D imaging method appropriate for planning and verification of proton radiation treatments, because it allows evaluating the distributions of proton stopping power within the tissues and can be directly utilized when the patient is in the actual treatment position. The aim of the PRoton IMAging experiment, supported by INFN, and the PRIN 2006 project, supported by MIUR, is to realize a proton computed radiography (pCR) prototype for reconstruction of proton images from a single projection in order to validate the technique with pre-clinical studies and, eventually, to conceive the configuration of a complete pCT system. A preliminary experiment performed at the 250 MeV proton synchrotron of Loma Linda University Medical Center (LLUMC) allowed acquisition of experimental data before the completion of PRIMA project's prototype. In this paper, the results of the LLUMC experiment are reported and the reconstruction of proton images of two phantoms is discussed.

  1. Simultaneous ion luminescence imaging and spectroscopy of individual aerosol particles with external proton or helium microbeams

    NASA Astrophysics Data System (ADS)

    Kada, Wataru; Satoh, Takahiro; Yokoyama, Akihito; Koka, Masashi; Kamiya, Tomihiro

    2014-08-01

    Simultaneous microscopic imaging and spectroscopy of individual aerosol particles were performed with an external microbeam. Visible luminescence induced by the external microbeam was successfully used as a probe to detect organic contaminants in the targets. Combined ion luminescence (IL)/particle-induced X-ray emission (PIXE) analysis of the aerosol targets revealed microscopic chemical and elemental composition distributions under ambient atmospheric conditions. The simple confocal micro-optics for the IL spectroscopy and microscopic imaging were sufficiently sensitive for detecting these molecules at sub-parts per million concentrations and at a wavelength resolution of less than 5 nm. The IL spectra were monitored to prevent severe damage to the samples. Furthermore, our IL system has the advantage that it is simple to add to a conventional micro-PIXE system.

  2. R1 correction in amide proton transfer imaging: indication of the influence of transcytolemmal water exchange on CEST measurements.

    PubMed

    Li, Hua; Li, Ke; Zhang, Xiao-Yong; Jiang, Xiaoyu; Zu, Zhongliang; Zaiss, Moritz; Gochberg, Daniel F; Gore, John C; Xu, Junzhong

    2015-12-01

    Amide proton transfer (APT) imaging may potentially detect mobile proteins/peptides non-invasively in vivo, but its specificity may be reduced by contamination from other confounding effects such as asymmetry of non-specific magnetization transfer (MT) effects and spin-lattice relaxation with rate R1 (=1/T1 ). Previously reported spillover, MT and R1 correction methods were based on a two-pool model, in which the existence of multiple water compartments with heterogeneous relaxation properties in real tissues was ignored. Such simple models may not adequately represent real tissues, and thus such corrections may be unreliable. The current study investigated the effectiveness and accuracy of correcting for R1 in APT imaging via simulations and in vivo experiments using tumor-bearing rats subjected to serial injections of Gd-DTPA that produced different tissue R1 values in regions of blood-brain-barrier breakdown. The results suggest that conventional measurements of APT contrast (such as APT* and MTRasym ) may be significantly contaminated by R1 variations, while the R1 -corrected metric AREX* was found to be relatively unaffected by R1 changes over a broad range (0.4-1 Hz). Our results confirm the importance of correcting for spin-lattice relaxation effects in quantitative APT imaging, and demonstrate the reliability of using the observed tissue R1 for corrections to obtain more specific and accurate measurements of APT contrast in vivo. The results also indicate that, due to relatively fast transcytolemmal water exchange, the influence of intra- and extracellular water compartments on CEST measurements with seconds long saturation time may be ignored in tumors. Copyright 2015 John Wiley & Sons, Ltd. PMID:26466161

  3. Pre- and Posttreatment Glioma: Comparison of Amide Proton Transfer Imaging with MR Spectroscopy for Biomarkers of Tumor Proliferation.

    PubMed

    Park, Ji Eun; Kim, Ho Sung; Park, Kye Jin; Kim, Sang Joon; Kim, Jeong Hoon; Smith, Seth A

    2016-02-01

    Purpose To correlate and compare diagnostic performance with amide proton transfer (APT) imaging as a tumor proliferation index with that with magnetic resonance (MR) spectroscopy in subgroups of patients with pre- and posttreatment glioma. Materials and Methods This retrospective study was approved by the institutional review board. In 40 patients with pretreatment glioma and 25 patients with posttreatment glioma, correlation between APT asymmetry and the choline-to-creatine and choline-to-N-acetylaspartate ratios in corresponding voxels of interest was determined, and the 90% histogram cutoff of APT asymmetry values (APT90) for the entire solid portion of gliomas was calculated for diagnostic performance. Area under the receiver operating characteristic curve (AUC), leave-one-out cross validation, and intraclass correlation coefficients were analyzed. Results The APT asymmetry values showed a moderate correlation (r = 0.49, P < .001) with the choline-to-creatine ratios and a mild correlation with the choline-to-N-acetyl-aspartate ratios (r = 0.32, P = .011) in the corresponding lesions. The APT90 showed comparable diagnostic accuracy for grading of gliomas (AUC, 0.81-0.84 vs 0.86; P = .582-.864) and superior accuracy for differentiation of tumor progression from treatment-related change (AUC, 0.89-0.90 vs 0.60; P = .031-.046) compared with those with MR spectroscopy. The cross-validated area under the curve and accuracy of the APT90 in posttreatment gliomas were 0.89-0.90 and 72%, respectively. The interreader agreement for APT90 was excellent in both pretreatment and posttreatment gliomas (intraclass correlation coefficient, 0.95 and 0.96, respectively). Conclusion APT imaging used as a tumor proliferation index showed moderate correlation with MR spectroscopic values and is a superior imaging method to MR spectroscopy, particularly for assessment of posttreatment gliomas. (©) RSNA, 2015 Online supplemental material is available for this article. PMID:26491847

  4. Proton radiography and tomography with application to proton therapy.

    PubMed

    Poludniowski, G; Allinson, N M; Evans, P M

    2015-09-01

    Proton radiography and tomography have long promised benefit for proton therapy. Their first suggestion was in the early 1960s and the first published proton radiographs and CT images appeared in the late 1960s and 1970s, respectively. More than just providing anatomical images, proton transmission imaging provides the potential for the more accurate estimation of stopping-power ratio inside a patient and hence improved treatment planning and verification. With the recent explosion in growth of clinical proton therapy facilities, the time is perhaps ripe for the imaging modality to come to the fore. Yet many technical challenges remain to be solved before proton CT scanners become commonplace in the clinic. Research and development in this field is currently more active than at any time with several prototype designs emerging. This review introduces the principles of proton radiography and tomography, their historical developments, the raft of modern prototype systems and the primary design issues. PMID:26043157

  5. Fatigue in Multiple Sclerosis: Assessing Pontine Involvement Using Proton MR Spectroscopic Imaging

    PubMed Central

    Zaini, Wan Hazlin; Giuliani, Fabrizio; Beaulieu, Christian; Kalra, Sanjay; Hanstock, Christopher

    2016-01-01

    Background/Objective The underlying mechanism of fatigue in multiple sclerosis (MS) remains poorly understood. Our study investigates the involvement of the ascending reticular activating system (ARAS), originating in the pontine brainstem, in MS patients with symptoms of fatigue. Methods Female relapsing-remitting MS patients (n = 17) and controls (n = 15) underwent a magnetic resonance spectroscopic imaging protocol at 1.5T. Fatigue was assessed in every subject using the Fatigue Severity Scale (FSS). Using an FSS cut-off of 36, patients were categorized into a low (n = 9, 22 ± 10) or high (n = 10, 52 ± 6) fatigue group. The brain metabolites N-acetylaspartate (NAA) and total creatine (tCr) were measured from sixteen 5x5x10 mm3 spectroscopic imaging voxels in the rostral pons. Results MS patients with high fatigue had lower NAA/tCr concentration in the tegmental pons compared to control subjects. By using NAA and Cr values in the cerebellum for comparison, these NAA/tCr changes in the pons were driven by higher tCr concentration, and that these changes were focused in the WM regions. Discussion/Conclusion Since there were no changes in NAA concentration, the increase in tCr may be suggestive of gliosis, or an imbalanced equilibrium of the creatine and phosphocreatine ratio in the pons of relapsing-remitting MS patients with fatigue. PMID:26895076

  6. Monte Carlo study on the sensitivity of prompt gamma imaging to proton range variations due to interfractional changes in prostate cancer patients

    NASA Astrophysics Data System (ADS)

    Schmid, S.; Landry, G.; Thieke, C.; Verhaegen, F.; Ganswindt, U.; Belka, C.; Parodi, K.; Dedes, G.

    2015-12-01

    Proton range verification based on prompt gamma imaging is increasingly considered in proton therapy. Tissue heterogeneity normal to the beam direction or near the end of range may considerably degrade the ability of prompt gamma imaging to detect proton range shifts. The goal of this study was to systematically investigate the accuracy and precision of range detection from prompt gamma emission profiles for various fractions for intensity modulated proton therapy of prostate cancer, using a comprehensive clinical dataset of 15 different CT scans for 5 patients. Monte Carlo simulations using Geant4 were performed to generate spot-by-spot dose distributions and prompt gamma emission profiles for prostate treatment plans. The prompt gammas were scored at their point of emission. Three CT scans of the same patient were used to evaluate the impact of inter-fractional changes on proton range. The range shifts deduced from the comparison of prompt gamma emission profiles in the planning CT and subsequent CTs were then correlated to the corresponding range shifts deduced from the dose distributions for individual pencil beams. The distributions of range shift differences between prompt gamma and dose were evaluated in terms of precision (defined as half the 95% inter-percentile range IPR) and accuracy (median). In total about 1700 individual proton pencil beams were investigated. The IPR of the relative range shift differences between the dose profiles and the prompt gamma profiles varied between  ±1.4 mm and  ±2.9 mm when using the more robust profile shifting analysis. The median was found smaller than 1 mm. Methods to identify and reject unreliable spots for range verification due to range mixing were derived and resulted in an average 10% spot rejection, clearly improving the prompt gamma–dose correlation. This work supports that prompt gamma imaging can offer a reliable indicator of range changes due to anatomical variations and tissue heterogeneity in scanning proton treatment of prostate cancer patients when considering prompt gamma emission profiles.

  7. Monte Carlo patient study on the comparison of prompt gamma and PET imaging for range verification in proton therapy

    NASA Astrophysics Data System (ADS)

    Moteabbed, M.; España, S.; Paganetti, H.

    2011-02-01

    The purpose of this work was to compare the clinical adaptation of prompt gamma (PG) imaging and positron emission tomography (PET) as independent tools for non-invasive proton beam range verification and treatment validation. The PG range correlation and its differences with PET have been modeled for the first time in a highly heterogeneous tissue environment, using different field sizes and configurations. Four patients with different tumor locations (head and neck, prostate, spine and abdomen) were chosen to compare the site-specific behaviors of the PG and PET images, using both passive scattered and pencil beam fields. Accurate reconstruction of dose, PG and PET distributions was achieved by using the planning computed tomography (CT) image in a validated GEANT4-based Monte Carlo code capable of modeling the treatment nozzle and patient anatomy in detail. The physical and biological washout phenomenon and decay half-lives for PET activity for the most abundant isotopes such as 11C, 15O, 13N, 30P and 38K were taken into account in the data analysis. The attenuation of the gamma signal after traversing the patient geometry and respective detection efficiencies were estimated for both methods to ensure proper comparison. The projected dose, PG and PET profiles along many lines in the beam direction were analyzed to investigate the correlation consistency across the beam width. For all subjects, the PG method showed on average approximately 10 times higher gamma production rates than the PET method before, and 60 to 80 times higher production after including the washout correction and acquisition time delay. This rate strongly depended on tissue density and elemental composition. For broad passive scattered fields, it was demonstrated that large differences exist between PG and PET signal falloff positions and the correlation with the dose distribution for different lines in the beam direction. These variations also depended on the treatment site and the particular subject. Thus, similar to PET, direct range verification with PG in passive scattering is not easily viable. However, upon development of an optimized 3D PG detector, indirect range verification by comparing measured and simulated PG distributions (currently being explored for the PET method) would be more beneficial because it can avoid the inherent biological challenges of the PET imaging. The improved correlation of PG and PET with dose when using pencil beams was evident. PG imaging was found to be potentially advantageous especially for small tumors in the presence of high tissue heterogeneities. Including the effects of detector acceptance and efficiency may hold PET superior in terms of the amplitude of the detected signal (depending on the future development of PG detection technology), but the ability to perform online measurements and avoid signal disintegration (due to washout) with PG are important factors that can outweigh the benefits of higher detection sensitivity.

  8. Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters

    NASA Astrophysics Data System (ADS)

    Cambraia Lopes, Patricia; Clementel, Enrico; Crespo, Paulo; Henrotin, Sebastien; Huizenga, Jan; Janssens, Guillaume; Parodi, Katia; Prieels, Damien; Roellinghoff, Frauke; Smeets, Julien; Stichelbaut, Frederic; Schaart, Dennis R.

    2015-08-01

    Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we present an initial performance test of two knife-edge slit camera prototypes based on arrays of digital photon counters (DPCs). PG profiles emitted from a PMMA target upon irradiation with a 160 MeV proton pencil beams (about 6.5   ×   109 protons delivered in total) were measured using detector modules equipped with four DPC arrays coupled to BGO or LYSO : Ce crystal matrices. The knife-edge slit collimator and detector module were placed at 15 cm and 30 cm from the beam axis, respectively, in all cases. The use of LYSO : Ce enabled time-of-flight (TOF) rejection of background events, by synchronizing the DPC readout electronics with the 106 MHz radiofrequency signal of the cyclotron. The signal-to-background (S/B) ratio of 1.6 obtained with a 1.5 ns TOF window and a 3 MeV-7 MeV energy window was about 3 times higher than that obtained with the same detector module without TOF discrimination and 2 times higher than the S/B ratio obtained with the BGO module. Even 1 mm shifts of the Bragg peak position translated into clear and consistent shifts of the PG profile if TOF discrimination was applied, for a total number of protons as low as about 6.5   ×   108 and a detector surface of 6.6 cm  ×  6.6 cm.

  9. 2D-1H proton magnetic resonance spectroscopic imaging study on brain metabolite alterations in patients with diabetic hypertension

    PubMed Central

    CAO, ZHEN; YE, BI-DI; SHEN, ZHI-WEI; CHENG, XIAO-FANG; YANG, ZHONG-XIAN; LIU, YAN-YAN; WU, REN-HUA; GENG, KUAN; XIAO, YE-YU

    2015-01-01

    The aim of the present study was to investigate the possible metabolic alterations in the frontal cortex and parietal white matter in patients with diabetic hypertension (DHT) using proton magnetic resonance (MR) spectroscopic imaging. A total of 33 DHT patients and 30 healthy control subjects aged between 45 and 75 were included in the present study. All subjects were right-handed. The spectroscopy data were collected using a GE Healthcare 1.5T MR scanner. The multi-voxels were located in the semioval center (repetition time/echo time=1,500 ms/35 ms). The area of interest was 8102 cm in volume and contained the two sides of the frontal cortex and the parietal white matter. The spectra data were processed using SAGE software. The ratios of brain metabolite concentrations, particularly for N-acetylaspartate (NAA)/creatine (Cr) and Choline (Cho)/Cr were calculated and analyzed. Statistical analyses were performed using SPSS 17.0. The NAA/Cr ratio of the bilateral prefrontal cortex of the DHT group was significantly lower than that of the control group (left t=?7.854, P=0.000 and right t= ?5.787, P=0.000), The Cho/Cr ratio was also much lower than the control group (left t=2.422, P=0.024 and right t=2.920, P=0.007). NAA/Cr ratio of the left parietal white matter of the DHT group was extremely lower than that of the control group (t=?4.199, P=0.000). Therefore, DHT may result in metabolic disorders in the frontal cortex and parietal white matter but the metabolic alterations are different in various regions of the brain. The alteration in cerebral metabolism is associated with diabetes and hypertension. The ratios of NAA/Cr and Cho/Cr are potential metabolic markers for the brain damage induced by DHT. PMID:25652580

  10. Fluorescent amino acid undergoing excited state intramolecular proton transfer for site-specific probing and imaging of peptide interactions.

    PubMed

    Sholokh, Marianna; Zamotaiev, Oleksandr M; Das, Ranjan; Postupalenko, Viktoriia Y; Richert, Ludovic; Dujardin, Denis; Zaporozhets, Olga A; Pivovarenko, Vasyl G; Klymchenko, Andrey S; Mly, Yves

    2015-02-12

    Fluorescent amino acids bearing environment-sensitive fluorophores are highly valuable tools for site-selective probing of peptide/ligand interactions. Herein, we synthesized a fluorescent l-amino acid bearing the 4'-methoxy-3-hydroxyflavone fluorophore (M3HFaa) that shows dual emission, as a result of an excited state intramolecular proton transfer (ESIPT). The dual emission of M3HFaa was found to be substantially more sensitive to hydration as compared to previous analogues. By replacing the Ala30 and Trp37 residues of a HIV-1 nucleocapsid peptide, M3HFaa was observed to preserve the peptide structure and functions. Interaction of the labeled peptides with nucleic acids and lipid vesicles produced a strong switch in their dual emission, favoring the emission of the ESIPT product. This switch was associated with the appearance of long-lived fluorescence lifetimes for the ESIPT product, as a consequence of the rigid environment in the complexes that restricted the relative motions of the M3HFaa aromatic moieties. The strongest restriction and thus the longest fluorescence lifetimes were observed at position 37 in complexes with nucleic acids, where the probe likely stacks with the nucleobases. Based on the dependence of the lifetime values on the nature of the ligand and the labeled position, two-photon fluorescence lifetime imaging was used to identify the binding partners of the labeled peptides microinjected into living cells. Thus, M3HFaa appears as a sensitive tool for monitoring site selectively peptide interactions in solution and living cells. PMID:25310178

  11. Longitudinal absolute metabolite quantification of white and gray matter regions in healthy controls using proton MR spectroscopic imaging.

    PubMed

    Wiebenga, Oliver T; Klauser, Antoine M; Nagtegaal, Gijsbert J A; Schoonheim, Menno M; Barkhof, Frederik; Geurts, Jeroen J G; Pouwels, Petra J W

    2014-03-01

    The purpose of this study was to evaluate quality parameters, metabolite concentrations and concentration ratios, and to investigate the reproducibility of quantitative proton magnetic resonance spectroscopic imaging ((1)H-MRSI) of selected white and gray matter regions of healthy adults. 2D-quantitative short-TE (1)H-MRSI spectra were obtained at 1.5T from the healthy human brain. Subjects (n?=?12) were scanned twice with an interval of six months. Absolute metabolite concentrations were obtained based on coil loading, taking into account differences in sensitivity of the phased-array head coil. Spectral quality parameters, absolute metabolite concentrations, concentration ratios, and their reproducibility were determined and compared between time-points using a repeated measures general linear model. The quality of the spectra of selected brain areas was good, as determined by a mean spectral linewidth between 4.8 and 7.3 Hz (depending on the region). No significant differences between the two time-points were observed for spectral quality, concentrations, or concentration ratios. The mean intrasubject coefficient of variation (CoV) varied between 4.0 and 8.5% for total N-acetylaspartate, 7.2 and 10.8% for total creatine, 5.9 and 9.8% for myo-inositol, and 8.0 and 13.3% for choline, and remained below 20% for glutamate. CoV was generally lower when concentration ratios were considered. The study shows that longitudinal quantitative short-TE (1)H-MRSI generates reproducible absolute metabolite concentrations in healthy human white and gray matter. This may serve as a background for longitudinal clinical studies in adult patients. PMID:24399803

  12. Multimodal Analysis of the Hippocampus in Schizophrenia Using Proton Magnetic Resonance Spectroscopy and Functional Magnetic Resonance Imaging

    PubMed Central

    Hutcheson, Nathan L.; Reid, Meredith A.; White, David M.; Kraguljac, Nina V.; Avsar, Kathy B.; Bolding, Mark S.; Knowlton, Robert C.; den Hollander, Jan A.; Lahti, Adrienne C.

    2012-01-01

    Background Studies have shown that individuals with schizophrenia suffer from memory impairments. In this study, we combined proton magnetic resonance spectroscopy (1H-MRS) and functional magnetic resonance imaging (fMRI) to clarify the neurobiology of memory deficits in schizophrenia. Methods We used single-voxel MRS acquired in the left hippocampus and fMRI during performance of a memory task to obtain measures of neurochemistry and functional response in 28 stable, medicated participants with schizophrenia (SZ) and 28 matched healthy controls (HC). Results The SZ group had significantly decreased blood oxygen level-dependent (BOLD) signal in left inferior frontal gyrus (IFG) during encoding and in the anterior cingulate cortex (ACC) and superior temporal gyrus (STG) during retrieval. We did not find significant differences in N-acetylaspartate/creatine (NAA/Cr) or glutamate + glutamine (Glx/Cr) levels between the groups, but did find a significant positive correlation between NAA/Cr and Glx/Cr in the HC group that was absent in the SZ group. There were no significant correlations between BOLD and MRS measured in the hippocampus. Further analyses revealed a negative correlation between left IFG BOLD and task performance in the SZ group. Finally, in the HC group, the left IFG BOLD was positively correlated with Glx/Cr. Conclusions We replicated findings of reduced BOLD signal in left IFG and of an altered relationship between IFG BOLD response and task performance in the SZ. The absence of correlation between NAA/Cr and Glx/Cr levels in patients might suggest underlying pathologies of the glutamate-glutamine cycle and/or mitochondria. PMID:22831772

  13. Commissioning of a proton gantry equipped with dual x-ray imagers and a robotic patient positioner, and evaluation of the accuracy of single-beam image registration for this system

    SciTech Connect

    Wang, Ning; Ghebremedhin, Abiel; Patyal, Baldev

    2015-06-15

    Purpose: To check the accuracy of a gantry equipped with dual x-ray imagers and a robotic patient positioner for proton radiotherapy, and to evaluate the accuracy and feasibility of single-beam registration using the robotic positioner. Methods: One of the proton treatment rooms at their institution was upgraded to include a robotic patient positioner (couch) with 6 degrees of freedom and dual orthogonal kilovoltage x-ray imaging panels. The wander of the proton beam central axis, the wander of the beamline, and the orthogonal image panel crosswires from the gantry isocenter were measured for different gantry angles. The couch movement accuracy and couch wander from the gantry isocenter were measured for couch loadings of 50–300 lb with couch rotations from 0° to ±90°. The combined accuracy of the gantry, couch, and imagers was checked using a custom-made 30 × 30 × 30 cm{sup 3} Styrofoam phantom with beekleys embedded in it. A treatment in this room can be set up and registered at a setup field location, then moved precisely to any other treatment location without requiring additional image registration. The accuracy of the single-beam registration strategy was checked for treatments containing multiple beams with different combinations of gantry angles, couch yaws, and beam locations. Results: The proton beam central axis wander from the gantry isocenter was within 0.5 mm with gantry rotations in both clockwise (CW) and counterclockwise (CCW) directions. The maximum wander of the beamline and orthogonal imager crosswire centers from the gantry isocenter were within 0.5 and 0.8 mm, respectively, with the gantry rotations in CW and CCW directions. Vertical and horizontal couch wanders from the gantry isocenter were within 0.4 and 1.3 mm, respectively, for couch yaw from 0° to ±90°. For a treatment with multiple beams with different gantry angles, couch yaws, and beam locations, the measured displacements of treatment beam locations from the one based on the initial setup beam registered at the gantry at 0°/180° and couch yaw at 0° were within 1.5 mm in three translations and 0.5° in three rotations for a 200 lb couch loading. Conclusions: Results demonstrate that the gantry equipped with a robotic patient positioner and dual imaging panels satisfies treatment requirements for proton radiotherapy. The combined accuracy of the gantry, couch, and imagers allows a patient to be registered at one setup position and then moved precisely to another treatment position by commanding the robotic patient positioner and delivering treatment without requiring additional image registration.

  14. Graphene oxide-Fe{sub 3}O{sub 4} nanoparticle composite with high transverse proton relaxivity value for magnetic resonance imaging

    SciTech Connect

    Venkatesha, N.; Srivastava, Chandan; Poojar, Pavan; Geethanath, Sairam; Qurishi, Yasrib

    2015-04-21

    The potential of graphene oxide–Fe{sub 3}O{sub 4} nanoparticle (GO-Fe{sub 3}O{sub 4}) composite as an image contrast enhancing material in magnetic resonance imaging has been investigated. Proton relaxivity values were obtained in three different homogeneous dispersions of GO-Fe{sub 3}O{sub 4} composites synthesized by precipitating Fe{sub 3}O{sub 4} nanoparticles in three different reaction mixtures containing 0.01 g, 0.1 g, and 0.2 g of graphene oxide. A noticeable difference in proton relaxivity values was observed between the three cases. A comprehensive structural and magnetic characterization revealed discrete differences in the extent of reduction of the graphene oxide and spacing between the graphene oxide sheets in the three composites. The GO-Fe{sub 3}O{sub 4} composite framework that contained graphene oxide with least extent of reduction of the carboxyl groups and largest spacing between the graphene oxide sheets provided the optimum structure for yielding a very high transverse proton relaxivity value. It was found that the GO-Fe{sub 3}O{sub 4} composites possessed good biocompatibility with normal cell lines, whereas they exhibited considerable toxicity towards breast cancer cells.

  15. Image-guided method for TLD-based in vivo rectal dose verification with endorectal balloon in proton therapy for prostate cancer

    SciTech Connect

    Hsi, Wen C.; Fagundes, Marcio; Zeidan, Omar; Hug, Eugen; Schreuder, Niek

    2013-05-15

    Purpose: To present a practical image-guided method to position an endorectal balloon that improves in vivo thermoluminiscent dosimeter (TLD) measurements of rectal doses in proton therapy for prostate cancer. Methods: TLDs were combined with endorectal balloons to measure dose at the anterior rectal wall during daily proton treatment delivery. Radiopaque metallic markers were employed as surrogates for balloon position reproducibility in rotation and translation. The markers were utilized to guide the balloon orientation during daily treatment employing orthogonal x-ray image-guided patient positioning. TLDs were placed at the 12 o'clock position on the anterior balloon surface at the midprostatic plane. Markers were placed at the 3 and 9 o'clock positions on the balloon to align it with respect to the planned orientation. The balloon rotation along its stem axis, referred to as roll, causes TLD displacement along the anterior-posterior direction. The magnitude of TLD displacement is revealed by the separation distance between markers at opposite sides of the balloon on sagittal x-ray images. Results: A total of 81 in vivo TLD measurements were performed on six patients. Eighty-three percent of all measurements (65 TLD readings) were within +5% and -10% of the planning dose with a mean of -2.1% and a standard deviation of 3.5%. Examination of marker positions with in-room x-ray images of measured doses between -10% and -20% of the planned dose revealed a strong correlation between balloon roll and TLD displacement posteriorly from the planned position. The magnitude of the roll was confirmed by separations of 10-20 mm between the markers which could be corrected by manually adjusting the balloon position and verified by a repeat x-ray image prior to proton delivery. This approach could properly correct the balloon roll, resulting in TLD positioning within 2 mm along the anterior-posterior direction. Conclusions: Our results show that image-guided TLD-based in vivo dosimetry for rectal dose verification can be perfomed reliably and reproducibly for proton therapy in prostate cancer.

  16. SU-E-J-82: Intra-Fraction Proton Beam-Range Verification with PET Imaging: Feasibility Studies with Monte Carlo Simulations and Statistical Modeling

    SciTech Connect

    Lou, K; Mirkovic, D; Sun, X; Zhu, X; Poenisch, F; Grosshans, D; Shao, Y; Clark, J

    2014-06-01

    Purpose: To study the feasibility of intra-fraction proton beam-range verification with PET imaging. Methods: Two phantoms homogeneous cylindrical PMMA phantoms (290 mm axial length, 38 mm and 200 mm diameter respectively) were studied using PET imaging: a small phantom using a mouse-sized PET (61 mm diameter field of view (FOV)) and a larger phantom using a human brain-sized PET (300 mm FOV). Monte Carlo (MC) simulations (MCNPX and GATE) were used to simulate 179.2 MeV proton pencil beams irradiating the two phantoms and be imaged by the two PET systems. A total of 50 simulations were conducted to generate 50 positron activity distributions and correspondingly 50 measured activity-ranges. The accuracy and precision of these activity-ranges were calculated under different conditions (including count statistics and other factors, such as crystal cross-section). Separate from the MC simulations, an activity distribution measured from a simulated PET image was modeled as a noiseless positron activity distribution corrupted by Poisson counting noise. The results from these two approaches were compared to assess the impact of count statistics on the accuracy and precision of activity-range calculations. Results: MC Simulations show that the accuracy and precision of an activity-range are dominated by the number (N) of coincidence events of the reconstructed image. They are improved in a manner that is inversely proportional to 1/sqrt(N), which can be understood from the statistical modeling. MC simulations also indicate that the coincidence events acquired within the first 60 seconds with 10{sup 9} protons (small phantom) and 10{sup 10} protons (large phantom) are sufficient to achieve both sub-millimeter accuracy and precision. Conclusion: Under the current MC simulation conditions, the initial study indicates that the accuracy and precision of beam-range verification are dominated by count statistics, and intra-fraction PET image-based beam-range verification is feasible. This work was supported by a research award RP120326 from Cancer Prevention and Research Institute of Texas.

  17. Proton therapy

    MedlinePLUS

    ... radiation because proton therapy causes less damage to healthy tissues. Side effects depend upon the area being treated, but may include skin redness in the radiation area, and temporary hair loss. AFTER THE PROCEDURE Following proton therapy, you ...

  18. Enantioselective Protonation

    PubMed Central

    Mohr, Justin T.; Hong, Allen Y.; Stoltz, Brian M.

    2010-01-01

    Enantioselective protonation is a common process in biosynthetic sequences. The decarboxylase and esterase enzymes that effect this valuable transformation are able to control both the steric environment around the proton acceptor (typically an enolate) and the proton donor (typically a thiol). Recently, several chemical methods to achieve enantioselective protonation have been developed by exploiting various means of enantiocontrol in different mechanisms. These laboratory transformations have proven useful for the preparation of a number of valuable organic compounds. PMID:20428461

  19. The localization-delocalization matrix and the electron-density-weighted connectivity matrix of a finite graphene nanoribbon reconstructed from kernel fragments.

    PubMed

    Timm, Matthew J; Matta, Chérif F; Massa, Lou; Huang, Lulu

    2014-11-26

    Bader's quantum theory of atoms in molecules (QTAIM) and chemical graph theory, merged in the localization-delocalization matrices (LDMs) and the electron-density-weighted connectivity matrices (EDWCM), are shown to benefit in computational speed from the kernel energy method (KEM). The LDM and EDWCM quantum chemical graph matrices of a 66-atom C46H20 hydrogen-terminated armchair graphene nanoribbon, in 14 (2×7) rings of C2v symmetry, are accurately reconstructed from kernel fragments. (This includes the full sets of electron densities at 84 bond critical points and 19 ring critical points, and the full sets of 66 localization and 4290 delocalization indices (LIs and DIs).) The average absolute deviations between KEM and directly calculated atomic electron populations, obtained from the sum of the LIs and half of the DIs of an atom, are 0.0012 ± 0.0018 e(-) (∼0.02 ± 0.03%) for carbon atoms and 0.0007 ± 0.0003 e(-) (∼0.01 ± 0.01%) for hydrogen atoms. The integration errors in the total electron population (296 electrons) are +0.0003 e(-) for the direct calculation (+0.0001%) and +0.0022 e(-) for KEM (+0.0007%). The accuracy of the KEM matrix elements is, thus, probably of the order of magnitude of the combined precision of the electronic structure calculation and the atomic integrations. KEM appears capable of delivering not only the total energies with chemical accuracy (which is well documented) but also local and nonlocal properties accurately, including the DIs between the fragments (crossing fragmentation lines). Matrices of the intact ribbon, the kernels, the KEM-reconstructed ribbon, and errors are available as Supporting Information . PMID:25343715

  20. Flash Proton Radiography

    NASA Astrophysics Data System (ADS)

    Merrill, Frank E.

    Protons were first investigated as radiographic probes as high energy proton accelerators became accessible to the scientific community in the 1960s. Like the initial use of X-rays in the 1800s, protons were shown to be a useful tool for studying the contents of opaque materials, but the electromagnetic charge of the protons opened up a new set of interaction processes which complicated their use. These complications in combination with the high expense of generating protons with energies high enough to penetrate typical objects resulted in proton radiography becoming a novelty, demonstrated at accelerator facilities, but not utilized to their full potential until the 1990s at Los Alamos. During this time Los Alamos National Laboratory was investigating a wide range of options, including X-rays and neutrons, as the next generation of probes to be used for thick object flash radiography. During this process it was realized that the charge nature of the protons, which was the source of the initial difficulty with this idea, could be used to recover this technique. By introducing a magnetic imaging lens downstream of the object to be radiographed, the blur resulting from scattering within the object could be focused out of the measurements, dramatically improving the resolution of proton radiography of thick systems. Imaging systems were quickly developed and combined with the temporal structure of a proton beam generated by a linear accelerator, providing a unique flash radiography capability for measurements at Los Alamos National Laboratory. This technique has now been employed at LANSCE for two decades and has been adopted around the world as the premier flash radiography technique for the study of dynamic material properties.

  1. A Proton Beam Therapy System Dedicated to Spot-Scanning Increases Accuracy with Moving Tumors by Real-Time Imaging and Gating and Reduces Equipment Size

    PubMed Central

    Shimizu, Shinichi; Miyamoto, Naoki; Matsuura, Taeko; Fujii, Yusuke; Umezawa, Masumi; Umegaki, Kikuo; Hiramoto, Kazuo; Shirato, Hiroki

    2014-01-01

    Purpose A proton beam therapy (PBT) system has been designed which dedicates to spot-scanning and has a gating function employing the fluoroscopy-based real-time-imaging of internal fiducial markers near tumors. The dose distribution and treatment time of the newly designed real-time-image gated, spot-scanning proton beam therapy (RGPT) were compared with free-breathing spot-scanning proton beam therapy (FBPT) in a simulation. Materials and Methods In-house simulation tools and treatment planning system VQA (Hitachi, Ltd., Japan) were used for estimating the dose distribution and treatment time. Simulations were performed for 48 motion parameters (including 8 respiratory patterns and 6 initial breathing timings) on CT data from two patients, A and B, with hepatocellular carcinoma and with clinical target volumes 14.6 cc and 63.1 cc. The respiratory patterns were derived from the actual trajectory of internal fiducial markers taken in X-ray real-time tumor-tracking radiotherapy (RTRT). Results With FBPT, 9/48 motion parameters achieved the criteria of successful delivery for patient A and 0/48 for B. With RGPT 48/48 and 42/48 achieved the criteria. Compared with FBPT, the mean liver dose was smaller with RGPT with statistical significance (p<0.001); it decreased from 27% to 13% and 28% to 23% of the prescribed doses for patients A and B, respectively. The relative lengthening of treatment time to administer 3 Gy (RBE) was estimated to be 1.22 (RGPT/FBPT: 138 s/113 s) and 1.72 (207 s/120 s) for patients A and B, respectively. Conclusions This simulation study demonstrated that the RGPT was able to improve the dose distribution markedly for moving tumors without very large treatment time extension. The proton beam therapy system dedicated to spot-scanning with a gating function for real-time imaging increases accuracy with moving tumors and reduces the physical size, and subsequently the cost of the equipment as well as of the building housing the equipment. PMID:24747601

  2. Evaluation of the dosimetric impact of interfractional anatomical variations on prostate proton therapy using daily in-room CT images

    PubMed Central

    Wang, Yi; Efstathiou, Jason A.; Sharp, Gregory C.; Lu, Hsiao-Ming; Frank Ciernik, I.; Trofimov, Alexei V.

    2011-01-01

    Purpose: To quantify interfractional anatomical variations and their dosimetric impact during the course of fractionated proton therapy (PT) of prostate cancer and to assess the robustness of the current treatment planning techniques. Methods: Simulation and daily in-room CT scans from ten prostate carcinoma patients were analyzed. PT treatment plans (78 Gy in 39 fractions of 2 Gy) were created on the simulation CT, delivering 25 fractions to PTV1 (expanded from prostate and seminal vesicles), followed by 14 boost fractions to PTV2 (expanded from prostate). Plans were subsequently applied to daily CT, with beams aligned to the prostate center in the sagittal plane. For five patients having a sufficiently large daily imaging volume, structure contours were manually drawn, and plans were evaluated for all CT sets. For the other five patients, the plans were evaluated for six selected fractions. The daily CT was matched to the simulation CT through deformable registration. The registration accuracy was validated for each fraction, and the three patients with a large number of accurately registered fractions were used for dose accumulation. Results: In individual fractions, the coverage of the prostate, seminal vesicles, and PTV1 was generally maintained at the corresponding prescription dose. For PTV2, the volume covered by the fractional prescription dose of 2 Gy (i.e., V2) was, on average, reduced by less than 3% compared to the simulation plan. Among the 225 (39??5?+?6??5) fractions examined, 15 showed a V2 reduction larger than 5%, of which ten were caused by a large variation in rectal gas, and five were due to a prostate shift in the craniocaudal direction. The fractional dose to the anterior rectal wall was found to increase for one patient who had large rectal gas volume in 25 of the 39 fractions, and another who experienced significant prostate volume reduction during the treatment. The fractional bladder dose generally increased with decreasing fullness. In the total accumulated dose for the three patients after excluding a few fractions with inaccurate registration due to a large amount of rectal gas (a condition inconsistent with RTOG protocol), 98.5%, 96.6%, and 98.2% of the PTV2 received the prescription dose of 78 Gy. The V75 and V70 of the anterior rectal wall and bladder both remained within tolerance. Conclusions: The results confirm that the PT planning techniques and dose constraints used at our institution ensure that target coverage to the prescription dose is maintained in the presence of interfractional anatomical variations. Dose coverage in individual fractions can be compromised, and normal tissue dose increased, due to deviations in the bladder and rectal volume compared to the simulation plans or progressive changes in the prostate volume during the treatment. Deviations from the plan can be reduced with efforts aimed at maintaining consistent daily patient anatomy. PMID:21928635

  3. In vitro NMR proton images/0031-9155/41/3/014/img1.gif"/> measurements in peritoneal ascites

    NASA Astrophysics Data System (ADS)

    Yilmaz, A.; Tez, M.; Gral, V.; Boylu, S.; Kaplan, A.; Kavak, G.

    1996-03-01

    The proton spin - lattice relaxation rate images/0031-9155/41/3/014/img10.gif" ALIGN="TOP"/> in malignant and non-malignant ascites was measured with an FT NMR spectrometer operating at 60 MHz. The mean relaxation rate in non-malignant ascites was significantly smaller than that of malignant ascites. However, the images/0031-9155/41/3/014/img11.gif" ALIGN="TOP"/> of malignant ascites overlaps with that of non-malignant ascites over all concentrations of total protein (TP) in samples. The images/0031-9155/41/3/014/img11.gif" ALIGN="TOP"/> in non-malignant ascites correlates strongly with TP, whilst the images/0031-9155/41/3/014/img11.gif" ALIGN="TOP"/> in malignant ascites shows only a moderate correlation. images/0031-9155/41/3/014/img14.gif" ALIGN="TOP"/> measurements before and after addition of ascorbic acid (reductant) suggest that there is a small paramagnetic contribution of ions to the images/0031-9155/41/3/014/img11.gif" ALIGN="TOP"/> in malignant ascites. The least-squares fitting of images/0031-9155/41/3/014/img11.gif" ALIGN="TOP"/> versus TP for non-malignant data gives a linear relationship, and suggests that the images/0031-9155/41/3/014/img14.gif" ALIGN="TOP"/> mechanism in non-malignant ascites is caused by a fast chemical exchange of water molecules between protein-bound water and free water.

  4. Visibility of epidermoid tumors on steady-state free precession images

    SciTech Connect

    Yuji Sakamoto; Mutsumasa Takahashi, Yukitaka, Ushio

    1994-10-01

    To determine whether steady-state free precession sequences improve the MR visibility of epidermoid tumors in comparison with spin-echo images. Patients were four women and three men with epidermoid tumors in the subarachnoid spaces. MR was performed with a 1.5-T superconductive unit. For steady-state free precession imaging, three-dimensional Fourier transform fast imaging with steady-state free precession (FISP) images were used (20-40/7[repetition time/echo time], flip angle of 25{degrees}). The visualization and contrast-to-noise ratio were compared in FISP images and spin-echo images. In one case, the images of FISP and fast low-angle shot were obtained with variable repetition times and flip angles to evaluate the best pulse sequences for the visualization of epidermoid tumors. The contrast-to-noise ratios between tumors and cerebrospinal fluid ranged from 7.9 to 17.5 (average was 12.9) on FISP images. The average of contrast-to-noise ratios on T1, T2 and proton density-weighted spin-echo images were 1.6, 2.0, and 4.2, respectively. Three-dimensional Fourier transform FISP images best showed central nervous system and demonstrated epidermoid tumors excellently. Epidermoid tumors in the subarachnoid spaces were better demonstrated on steady-state free precession (three-dimensional Fourier transform FISP) than on conventional spin-echo images. 13 refs., 5 figs., 2 tabs.

  5. Ring current proton precipitation as displayed by the proton aurora

    NASA Astrophysics Data System (ADS)

    Yahnin, Alexander

    We review recent studies of precipitation of the ring current energetic protons based on obser-vations of proton aurora and direct measurements of energetic particle fluxes by low orbiting satellites. The proton aurora oval is formed by the precipitation of the plasma sheet and outer radiation belt protons scattered into the loss cone due to violation of their adiabatic motion in the region of weak magnetic field (e.g., in the equatorial plane of the nightside magneto-sphere). Equatorward of the proton oval, various detached proton aurora forms have been recently observed onboard the IMAGE spacecraft. The comparison of the sub-oval proton au-rora and electromagnetic ion-cyclotron (EMIC) wave observations in space and on the ground demonstrated that proton precipitation producing these auroras is the result of interaction of the ring current protons and EMIC waves. On the ground, EMIC waves are observed as ge-omagnetic pulsations of the Pc1 range. Different types of the sub-oval proton auroras (such as proton spots, evening-side proton arcs, proton flashes on the dayside) were found to be re-lated with different kinds of the Pc1 pulsations (such as "monochromatic Pc1" during quiet geomagnetic conditions, pulsations with diminishing periods during substorm injections, wide-band "Pc1 bursts" during magnetosphere compressions) representing different regimes of the ion-cyclotron interaction. Close spatial-temporal correlation between sub-oval proton auroras and EMIC waves means that the auroras visualize on the ionospheric "screen" the configuration of the magnetospheric region of the ion-cyclotron interaction and allow monitoring its dynam-ics. Furthermore, since the ion-cyclotron instability typically develops when the ring current particles contact the cold plasma the proton aurora observations provide a tool for monitoring the location of plasmapause and detached plasmaspheric structures.

  6. T1 weighted brain images at 7 Tesla unbiased for Proton Density, T2* contrast and RF coil receive B1 sensitivity with simultaneous vessel visualization.

    PubMed

    Van de Moortele, Pierre-Franois; Auerbach, Edwards J; Olman, Cheryl; Yacoub, Essa; U?urbil, Kmil; Moeller, Steen

    2009-06-01

    At high magnetic field, MR images exhibit large, undesirable signal intensity variations commonly referred to as "intensity field bias". Such inhomogeneities mostly originate from heterogeneous RF coil B(1) profiles and, with no appropriate correction, are further pronounced when utilizing rooted sum of square reconstruction with receive coil arrays. These artifacts can significantly alter whole brain high resolution T(1)-weighted (T(1)w) images that are extensively utilized for clinical diagnosis, for gray/white matter segmentation as well as for coregistration with functional time series. In T(1) weighted 3D-MPRAGE sequences, it is possible to preserve a bulk amount of T(1) contrast through space by using adiabatic inversion RF pulses that are insensitive to transmit B(1) variations above a minimum threshold. However, large intensity variations persist in the images, which are significantly more difficult to address at very high field where RF coil B(1) profiles become more heterogeneous. Another characteristic of T(1)w MPRAGE sequences is their intrinsic sensitivity to Proton Density and T(2)(*) contrast, which cannot be removed with post-processing algorithms utilized to correct for receive coil sensitivity. In this paper, we demonstrate a simple technique capable of producing normalized, high resolution T(1)w 3D-MPRAGE images that are devoid of receive coil sensitivity, Proton Density and T(2)(*) contrast. These images, which are suitable for routinely obtaining whole brain tissue segmentation at 7 T, provide higher T(1) contrast specificity than standard MPRAGE acquisitions. Our results show that removing the Proton Density component can help in identifying small brain structures and that T(2)(*) induced artifacts can be removed from the images. The resulting unbiased T(1)w images can also be used to generate Maximum Intensity Projection angiograms, without additional data acquisition, that are inherently registered with T(1)w structural images. In addition, we introduce a simple technique to reduce residual signal intensity variations induced by transmit B(1) heterogeneity. Because this approach requires two 3D images, one divided with the other, head motion could create serious problems, especially at high spatial resolution. To alleviate such inter-scan motion problems, we developed a new sequence where the two contrast acquisitions are interleaved within a single scan. This interleaved approach however comes with greater risk of intra-scan motion issues because of a longer single scan time. Users can choose between these two trade offs depending on specific protocols and patient populations. We believe that the simplicity and the robustness of this double contrast based approach to address intensity field bias at high field and improve T(1) contrast specificity, together with the capability of simultaneously obtaining angiography maps, advantageously counter balance the potential drawbacks of the technique, mainly a longer acquisition time and a moderate reduction in signal to noise ratio. PMID:19233292

  7. Sparse-view proton computed tomography using modulated proton beams

    SciTech Connect

    Lee, Jiseoc; Kim, Changhwan; Cho, Seungryong; Min, Byungjun; Kwak, Jungwon; Park, Seyjoon; Lee, Se Byeong; Park, Sungyong

    2015-02-15

    Purpose: Proton imaging that uses a modulated proton beam and an intensity detector allows a relatively fast image acquisition compared to the imaging approach based on a trajectory tracking detector. In addition, it requires a relatively simple implementation in a conventional proton therapy equipment. The model of geometric straight ray assumed in conventional computed tomography (CT) image reconstruction is however challenged by multiple-Coulomb scattering and energy straggling in the proton imaging. Radiation dose to the patient is another important issue that has to be taken care of for practical applications. In this work, the authors have investigated iterative image reconstructions after a deconvolution of the sparsely view-sampled data to address these issues in proton CT. Methods: Proton projection images were acquired using the modulated proton beams and the EBT2 film as an intensity detector. Four electron-density cylinders representing normal soft tissues and bone were used as imaged object and scanned at 40 views that are equally separated over 360°. Digitized film images were converted to water-equivalent thickness by use of an empirically derived conversion curve. For improving the image quality, a deconvolution-based image deblurring with an empirically acquired point spread function was employed. They have implemented iterative image reconstruction algorithms such as adaptive steepest descent-projection onto convex sets (ASD-POCS), superiorization method–projection onto convex sets (SM-POCS), superiorization method–expectation maximization (SM-EM), and expectation maximization-total variation minimization (EM-TV). Performance of the four image reconstruction algorithms was analyzed and compared quantitatively via contrast-to-noise ratio (CNR) and root-mean-square-error (RMSE). Results: Objects of higher electron density have been reconstructed more accurately than those of lower density objects. The bone, for example, has been reconstructed within 1% error. EM-based algorithms produced an increased image noise and RMSE as the iteration reaches about 20, while the POCS-based algorithms showed a monotonic convergence with iterations. The ASD-POCS algorithm outperformed the others in terms of CNR, RMSE, and the accuracy of the reconstructed relative stopping power in the region of lung and soft tissues. Conclusions: The four iterative algorithms, i.e., ASD-POCS, SM-POCS, SM-EM, and EM-TV, have been developed and applied for proton CT image reconstruction. Although it still seems that the images need to be improved for practical applications to the treatment planning, proton CT imaging by use of the modulated beams in sparse-view sampling has demonstrated its feasibility.

  8. Three-Dimensional Turbo-Spin-Echo Amide Proton Transfer MR Imaging at 3 Tesla and Its Application to High-Grade Human Brain Tumors

    PubMed Central

    Zhao, Xuna; Wen, Zhibo; Zhang, Ge; Huang, Fanheng; Lu, Shilong; Wang, Xianlong; Hu, Shuguang; Chen, Min; Zhou, Jinyuan

    2012-01-01

    Purpose Amide proton transfer (APT) imaging is able to extend the achievable MRI contrast to the protein level. In this study, we demonstrate the feasibility of applying a turbo spin echo (TSE)-based, three-dimensional (3D) APT sequence into routine clinical practice for patients with brain tumors. Procedures Experiments were performed on a Philips 3T MRI scanner using an eight-channel phased-array coil for reception. A fast 3D APT sequence with a TSE acquisition was proposed (saturation power, 2 μT; saturation time, 500 ms; 8 slices). The gradient echo (GRE)-based field-mapping technique or water-saturation-shift-referencing (WASSR) technique was used to acquire B0 maps to correct for B0-induced artifacts in APT images. The test was performed on a box of homogenous protein solution, four healthy volunteers, and eight patients with high-grade gliomas. Results The experimental data from a homogenous, protein-containing phantom and healthy volunteers show that the sequence produced a uniform contrast across all slices. The average MTRasym(3.5ppm) values with GRE B0-corrected 3D APT imaging and WASSR-corrected 3D APT imaging were both comparable to the values obtained using the undemanding single-slice acquisition. The average APT image intensity was consistently higher in the tumor core than in the peripheral edema and in the contralateral normal-appearing white matter (both P < 0.001). Conclusion 3D APT imaging of brain tumors can be performed in about five minutes at 3T using a routine, commercial eight-channel SENSE coil. PMID:22644987

  9. An imaging informatics-based system utilizing DICOM objects for treating pain in spinal cord injury patients utilizing proton beam radiotherapy

    NASA Astrophysics Data System (ADS)

    Verma, Sneha K.; Liu, Brent J.; Chun, Sophia; Gridley, Daila S.

    2014-03-01

    Many US combat personnel have sustained nervous tissue trauma during service, which often causes Neuropathic pain as a side effect and is difficult to manage. However in select patients, synapse lesioning can provide significant pain control. Our goal is to determine the effectiveness of using Proton Beam radiotherapy for treating spinal cord injury (SCI) related neuropathic pain as an alternative to invasive surgical lesioning. The project is a joint collaboration of USC, Spinal Cord Institute VA Healthcare System, Long Beach, and Loma Linda University. This is first system of its kind that supports integration and standardization of imaging informatics data in DICOM format; clinical evaluation forms outcomes data and treatment planning data from the Treatment planning station (TPS) utilized to administer the proton therapy in DICOM-RT format. It also supports evaluation of SCI subjects for recruitment into the clinical study, which includes the development, and integration of digital forms and tools for automatic evaluation and classification of SCI pain. Last year, we presented the concept for the patient recruitment module based on the principle of Bayesian decision theory. This year we are presenting the fully developed patient recruitment module and its integration to other modules. In addition, the DICOM module for integrating DICOM and DICOM-RT-ION data is also developed and integrated. This allows researchers to upload animal/patient study data into the system. The patient recruitment module has been tested using 25 retrospective patient data and DICOM data module is tested using 5 sets of animal data.

  10. Proton Microscopy at Fair

    NASA Astrophysics Data System (ADS)

    Merrill, F. E.; Golubev, A. A.; Mariam, F. G.; Turtikov, V. I.; Varentsov, D.

    2009-12-01

    Proton radiography was invented in the 1990's at Los Alamos National Laboratory (LANL) as a diagnostic to study dynamic material properties under extreme pressures, strain and strain rate. Since this time hundreds of dynamic proton radiography experiments have been performed at LANL and a facility has been commissioned at the Institute for Theoretical and Experimental Physics (ITEP) in Russia for similar applications in dynamic material studies. Recently an international effort has investigated a new proton radiography capability for the study of dynamic material properties at the Facility for Anti-proton and Ion Research (FAIR) located in Darmstadt, Germany. This new Proton microscope for FAIR (PRIOR) will provide radiographic imaging of dynamic systems with unprecedented spatial, temporal and density resolution, resulting in a window for understanding dynamic material properties at new length scales. It is also proposed to install the PRIOR system at the GSI Helmholtzzentrum für Schwerionenforschung before installation at FAIR for dynamic experiments with different drivers including high explosives, pulsed power and lasers. The design of the proton microscope and expected radiographic performance is presented.

  11. A Web application for the management of clinical workflow in image-guided and adaptive proton therapy for prostate cancer treatments.

    PubMed

    Yeung, Daniel; Boes, Peter; Ho, Meng Wei; Li, Zuofeng

    2015-01-01

    Image-guided radiotherapy (IGRT), based on radiopaque markers placed in the prostate gland, was used for proton therapy of prostate patients. Orthogonal X-rays and the IBA Digital Image Positioning System (DIPS) were used for setup correction prior to treatment and were repeated after treatment delivery. Following a rationale for margin estimates similar to that of van Herk,(1) the daily post-treatment DIPS data were analyzed to determine if an adaptive radiotherapy plan was necessary. A Web application using ASP.NET MVC5, Entity Framework, and an SQL database was designed to automate this process. The designed features included state-of-the-art Web technologies, a domain model closely matching the workflow, a database-supporting concurrency and data mining, access to the DIPS database, secured user access and roles management, and graphing and analysis tools. The Model-View-Controller (MVC) paradigm allowed clean domain logic, unit testing, and extensibility. Client-side technologies, such as jQuery, jQuery Plug-ins, and Ajax, were adopted to achieve a rich user environment and fast response. Data models included patients, staff, treatment fields and records, correction vectors, DIPS images, and association logics. Data entry, analysis, workflow logics, and notifications were implemented. The system effectively modeled the clinical workflow and IGRT process. PMID:26103504

  12. An experimental approach to improve the Monte Carlo modelling of offline PET/CT-imaging of positron emitters induced by scanned proton beams

    NASA Astrophysics Data System (ADS)

    Bauer, J.; Unholtz, D.; Kurz, C.; Parodi, K.

    2013-08-01

    We report on the experimental campaign carried out at the Heidelberg Ion-Beam Therapy Center (HIT) to optimize the Monte Carlo (MC) modelling of proton-induced positron-emitter production. The presented experimental strategy constitutes a pragmatic inverse approach to overcome the known uncertainties in the modelling of positron-emitter production due to the lack of reliable cross-section data for the relevant therapeutic energy range. This work is motivated by the clinical implementation of offline PET/CT-based treatment verification at our facility. Here, the irradiation induced tissue activation in the patient is monitored shortly after the treatment delivery by means of a commercial PET/CT scanner and compared to a MC simulated activity expectation, derived under the assumption of a correct treatment delivery. At HIT, the MC particle transport and interaction code FLUKA is used for the simulation of the expected positron-emitter yield. For this particular application, the code is coupled to externally provided cross-section data of several proton-induced reactions. Studying experimentally the positron-emitting radionuclide yield in homogeneous phantoms provides access to the fundamental production channels. Therefore, five different materials have been irradiated by monoenergetic proton pencil beams at various energies and the induced ?+ activity subsequently acquired with a commercial full-ring PET/CT scanner. With the analysis of dynamically reconstructed PET images, we are able to determine separately the spatial distribution of different radionuclide concentrations at the starting time of the PET scan. The laterally integrated radionuclide yields in depth are used to tune the input cross-section data such that the impact of both the physical production and the imaging process on the various positron-emitter yields is reproduced. The resulting cross-section data sets allow to model the absolute level of measured ?+ activity induced in the investigated targets within a few per cent. Moreover, the simulated distal activity fall-off positions, representing the central quantity for treatment monitoring in terms of beam range verification, are found to agree within 0.6 mm with the measurements at different initial beam energies in both homogeneous and heterogeneous targets. Based on work presented at the Third European Workshop on Monte Carlo Treatment Planning (Seville, 15-18 May 2012).

  13. An experimental approach to improve the Monte Carlo modelling of offline PET/CT-imaging of positron emitters induced by scanned proton beams.

    PubMed

    Bauer, J; Unholtz, D; Kurz, C; Parodi, K

    2013-08-01

    We report on the experimental campaign carried out at the Heidelberg Ion-Beam Therapy Center (HIT) to optimize the Monte Carlo (MC) modelling of proton-induced positron-emitter production. The presented experimental strategy constitutes a pragmatic inverse approach to overcome the known uncertainties in the modelling of positron-emitter production due to the lack of reliable cross-section data for the relevant therapeutic energy range. This work is motivated by the clinical implementation of offline PET/CT-based treatment verification at our facility. Here, the irradiation induced tissue activation in the patient is monitored shortly after the treatment delivery by means of a commercial PET/CT scanner and compared to a MC simulated activity expectation, derived under the assumption of a correct treatment delivery. At HIT, the MC particle transport and interaction code FLUKA is used for the simulation of the expected positron-emitter yield. For this particular application, the code is coupled to externally provided cross-section data of several proton-induced reactions. Studying experimentally the positron-emitting radionuclide yield in homogeneous phantoms provides access to the fundamental production channels. Therefore, five different materials have been irradiated by monoenergetic proton pencil beams at various energies and the induced ?(+) activity subsequently acquired with a commercial full-ring PET/CT scanner. With the analysis of dynamically reconstructed PET images, we are able to determine separately the spatial distribution of different radionuclide concentrations at the starting time of the PET scan. The laterally integrated radionuclide yields in depth are used to tune the input cross-section data such that the impact of both the physical production and the imaging process on the various positron-emitter yields is reproduced. The resulting cross-section data sets allow to model the absolute level of measured ?(+) activity induced in the investigated targets within a few per cent. Moreover, the simulated distal activity fall-off positions, representing the central quantity for treatment monitoring in terms of beam range verification, are found to agree within 0.6mm with the measurements at different initial beam energies in both homogeneous and heterogeneous targets. PMID:23835872

  14. Differentiation of silicone gel from water and fat in MR phase imaging of protons at 0.064 T.

    PubMed

    Derby, K A; Frankel, S D; Kaufman, L; Carlson, J W; Mineyev, M I; Occhipinti, K A; Friedenthal, R

    1993-11-01

    The authors present a method of identifying silicone at magnetic resonance (MR) imaging based on its chemical shift. The method relies on phase images reconstructed from a gradient-recalled-echo sequence that has an echo time chosen to maximize the phase offsets between water, fat, and silicone. Results from studies at 0.064 T of both phantoms and human subjects are presented. This technique was useful in identifying extracapsular silicone and may be applicable at other field strengths. PMID:8210399

  15. Proton Transport

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The transport of protons across membranes is an essential process for both bioenergetics of modern cells and the origins of cellular life. All living systems make use of proton gradients across cell walls to convert environmental energy into a high-energy chemical compound, adenosine triphosphate (ATP), synthesized from adenosine diphosphate. ATP, in turn, is used as a source of energy to drive many cellular reactions. The ubiquity of this process in biology suggests that even the earliest cellular systems were relying on proton gradient for harvesting environmental energy needed to support their survival and growth. In contemporary cells, proton transfer is assisted by large, complex proteins embedded in membranes. The issue addressed in this Study was: how the same process can be accomplished with the aid of similar but much simpler molecules that could have existed in the protobiological milieu? The model system used in the study contained a bilayer membrane made of phospholipid, dimyristoylphosphatidylcholine (DMPC) which is a good model of the biological membranes forming cellular boundaries. Both sides of the bilayer were surrounded by water which simulated the environment inside and outside the cell. Embedded in the membrane was a fragment of the Influenza-A M$_2$ protein and enough sodium counterions to maintain system neutrality. This protein has been shown to exhibit remarkably high rates of proton transport and, therefore, is an excellent model to study the formation of proton gradients across membranes. The Influenza M$_2$ protein is 97 amino acids in length, but a fragment 25 amino acids long. which contains a transmembrane domain of 19 amino acids flanked by three amino acids on each side. is sufficient to transport protons. Four identical protein fragments, each folded into a helix, aggregate to form small channels spanning the membrane. Protons are conducted through a narrow pore in the middle of the channel in response to applied voltage. This channel is large enough to contain water molecules. and is normally filled with water. In analogy to the mechanism of proton transfer in some other channels, it has been postulated that protons are translocated along the network of water molecules filling the pore of the channel. This mechanism, however, must involve an additional important step because the channel contains four histidine amino acid residues, one from each of the helices, which are sufficiently large to occlude the pore and interrupt the water network. The histidine residues ensure channel selectivity by blocking transport of small ions, such as sodium or potassium. They have been also implicated in gating protons due to the ability of each histidine to become positively charged by accepting an additional proton. Two mechanisms of gating have been proposed. In one mechanism, all four histidines acquire an additional proton and, due to repulsion between their positive charges, move away from one another, thus opening the channel. The alternative mechanism relies of the ability of protons to move between different atoms in a molecule (tautomerization). Thus, a proton is captured on one side of the gate while another proton is released from the opposite side, and the molecule returns to the initial state through tautomerization. The simulations were designed to test these two mechanisms. Large-scale, atomic-level molecular dynamics simulations of the channel with the histidine residues in different protonation states revealed that all intermediate states of the system involved in the tautomerization mechanism are structurally stable and the arrangement of water molecules in the channel is conducive to the proton transport. In contrast, in the four-protonated state, postulated to exist in the gate-opening mechanism, the electrostatic repulsion between the histidine residues appears to be so large that the channel loses its structural integrity and one helix moves away from the remaining three. Additional information is contained within the original extended abstract.

  16. Figures of merit for focusing mega-electron-volt ion beams in biomedical imaging and proton beam writing

    SciTech Connect

    Ren Minqin; Whitlow, Harry J.; Ananda Sagari, A. R.; Kan, Jeroen A. van; Osipowicz, Thomas; Watt, Frank

    2008-01-01

    A figure of merit (FOM) has been developed for focusing quadrupole multiplet lenses for ion micro- and nanobeam systems. The method which is based on measurement of the central peak of the two-dimensional autocorrelation function of an image provides separate FOM for the horizontal and vertical directions. The approach has been tested by comparison with the edge widths obtained by nonlinear fitting the edge widths of a Ni grid and found to be reliable. The FOM has the important advantage for ion beam imaging of biomedical samples that the fluence needed is considerably lower than for edge fitting.

  17. Translational Approaches for Studying Neurodevelopmental Disorders Utilizing in Vivo Proton (+H) Magnetic Resonance Spectroscopic Imaging in Rats

    NASA Technical Reports Server (NTRS)

    Ronca, April E.

    2014-01-01

    Intrauterine complications have been implicated in the etiology of neuripsychiatric disorders including schizophrenia, autism and ADHD. This presentation will describe new translational studies derived from in vivo magnetic resonance imaging of developing and adult brain following perinatal asphyxia (PA). Our findings reveal significant effects of PA on neurometabolic profiles at one week of age, and significant relationships between early metabolites and later life phenotypes including behavior and brain morphometry

  18. On proton CT reconstruction using MVCT-converted virtual proton projections

    SciTech Connect

    Wang Dongxu; Mackie, T. Rockwell; Tome, Wolfgang A.

    2012-06-15

    Purpose: To describe a novel methodology of converting megavoltage x-ray projections into virtual proton projections that are otherwise missing due to the proton range limit. These converted virtual proton projections can be used in the reconstruction of proton computed tomography (pCT). Methods: Relations exist between proton projections and multispectral megavoltage x-ray projections for human tissue. Based on these relations, these tissues can be categorized into: (a) adipose tissue; (b) nonadipose soft tissues; and (c) bone. These three tissue categories can be visibly identified on a regular megavoltage x-ray computed tomography (MVCT) image. With an MVCT image and its projection data available, the x-ray projections through heterogeneous anatomy can be converted to the corresponding proton projections using predetermined calibration curves for individual materials, aided by a coarse segmentation on the x-ray CT image. To show the feasibility of this approach, mathematical simulations were carried out. The converted proton projections, plotted on a proton sinogram, were compared to the simulated ground truth. Proton stopping power images were reconstructed using either the virtual proton projections only or a blend of physically available proton projections and virtual proton projections that make up for those missing due to the range limit. These images were compared to a reference image reconstructed from theoretically calculated proton projections. Results: The converted virtual projections had an uncertainty of {+-}0.8% compared to the calculated ground truth. Proton stopping power images reconstructed using a blend of converted virtual projections (48%) and physically available projections (52%) had an uncertainty of {+-}0.86% compared with that reconstructed from theoretically calculated projections. Reconstruction solely from converted virtual proton projections had an uncertainty of {+-}1.1% compared with that reconstructed from theoretical projections. If these images are used for treatment planning, the average proton range uncertainty is estimated to be less than 1.5% for an imaging dose in the milligray range. Conclusions: The proposed method can be used to convert x-ray projections into virtual proton projections. The converted proton projections can be blended with existing proton projections or can be used solely for pCT reconstruction, addressing the range limit problem of pCT using current therapeutic proton machines.

  19. Postoperative fluid-attenuated inversion recovery MR imaging of cerebral gliomas: initial results.

    PubMed

    Essig, M; Metzner, R; Bonsanto, M; Hawighorst, H; Debus, J; Tronnier, V; Knopp, M V; van Kaick, G

    2001-01-01

    Fluid-attenuated inversion-recovery (FLAIR) imaging has shown to be a valuable imaging modality in the assessment of intra-axial brain tumors; however, no data are available about the role of this technique in the clinically important postoperative stage. The purpose of this study was to evaluate the diagnostic potential of FLAIR MR imaging in residual tumor after surgical resection of cerebral gliomas. Fifteen patients with residual cerebral gliomas were examined within the first 18 days after partial surgical resection of cerebral gliomas. The imaging protocol included T1-weighted spin echo, T2- and proton-density-weighted fast spin echo, and FLAIR imaging with identical slice parameters. T1 and FLAIR were repeated after contrast media application. Detection and delineation of residual tumor were the primary parameters of the image analysis. Additionally, the influence of image artifacts on the image interpretation was assessed. On FLAIR images residual signal abnormalities at the border of the resection cavities were observed in all patients, whereas T2- and T1-weighted images present residual abnormalities in 13 of 15 and 10 of 15 patients, respectively. The FLAIR imaging was found to be superior to conventional imaging sequences in the delineation of these changes and comparable to contrast enhanced T1-weighted imaging in the delineation of residual enhancing lesions. Because of protein cell components and blood byproducts within the resection cavity, FLAIR imaging was unable to suppress the cerebrospinal fluid (CSF) in 4 patients. After the decomposition of proteins and blood, CSF could again be completely suppressed and residual or recurrent tumors were clearly identified. Our preliminary study has shown that FLAIR may be a valuable diagnostic modality in the early postoperative MR imaging after resection of cerebral gliomas due to its better delineation of residual pathologic signal at the border of the resection cavity. It should therefore be integrated into the early and/or intraoperative MR imaging protocol. PMID:11702135

  20. Statistical mapping of metabolites in the medial wall of the brain: a proton echo planar spectroscopic imaging study.

    PubMed

    Niddam, David M; Tsai, Shang-Yueh; Lin, Yi-Ru

    2015-03-01

    With magnetic resonance spectroscopic imaging (MRSI), it is possible to simultaneously map distributions of several brain metabolites with relatively good spatial resolution in a short time. Although other functional imaging modalities have taken advantage of population-based inferences using spatially extended statistics, this approach remains little utilized for MRSI. In this study, statistical nonparametric mapping (SnPM) was applied to two-dimensional MRSI data from the medial walls of the human brain to assess the effect of normal aging on metabolite concentrations. The effects of different preprocessing steps on these results were then explored. Short echo time MRSI of left and right medial walls was acquired in conjunction with absolute quantification of total choline, total creatine (tCr), glutamate and glutamine, myo-inositol, and N-acetyl-aspartate. Individual images were spatially warped to a common anatomical frame of reference. Age effects were assessed within SnPM as were the effects of voxel subsampling, variance smoothing, and spatial smoothing. The main findings were: (1) regions in the bilateral dorsal anterior cingulate and in the left posterior cingulate exhibited higher tCr concentrations with age; (2) voxel subsampling but not spatial smoothing enhanced the cluster-level statistical sensitivity; and (3) variance smoothing was of little benefit in this study. Our study shows that spatially extended statistics can yield information about regional-specific changes in metabolite concentrations obtained by short echo time MRSI. This opens up the possibility for systematic comparisons of metabolites in the medial wall of the brain. PMID:25338521

  1. Towards Proton Therapy and Radiography at FAIR

    NASA Astrophysics Data System (ADS)

    Prall, M.; Lang, P. M.; LaTessa, C.; Mariam, F.; Merrill, F.; Shestov, L.; Simoniello, P.; Varentsov, D.; Durante, M.

    2015-04-01

    Protons having energies in the GeV range have been proposed as an alternative to Bragg-peak hadron therapy. This strategy reduces lateral scattering and overcomes uncertainties of particle range and relative biological effectiveness. GeV protons could additionally be used for targeting in image guided stereotactic radiosurgery. We experimentally demonstrated the potential of GeV protons for imaging of biological samples using E=0.8 GeV protons and the pRad setup at Los Alamos National Laboratory (LANL). In this setup, a system of magnetic lenses creates a point-to-point mapping from object to detector. This mapping compensates image blur due to lateral scattering inside the imaged (biological) object. We produced 2-dim proton radiographs of biological samples, an anthropomorphic phantom and performed simple dosimetry. High resolution tomographic reconstructions were derived from the 2-dim proton radiographs. Our experiment was performed within the framework of the PANTERA (Proton Therapy and Radiography) project. In the future, the proton microscope PRIOR (Proton Microscope for FAIR) located in the FAIR facility (Darmstadt), will focus on optimizing the technique for imaging of lesions implanted in animals and couple the irradiation with standard radiotherapy.

  2. Electron and Proton Auroral Dynamics

    NASA Astrophysics Data System (ADS)

    Mende, S. B.; Frey, H. U.; Carlson, C.; Immel, T.; Gerard, J.; Hubert, B.; Fuselier, S.; Spann, J.; Gladstone, R.; Burch, J. L.

    2001-05-01

    Data from the IMAGE Wide-band Imaging Camera (WIC),sensitive to far ultraviolet auroras and from the Spectrographic Imager (SI) channel SI12, sensitive to proton precipitation induced Lyman alpha, were analyzed during a high altitude orbit segment of the IMAGE spacecraft. This segment began during the expansive phase of a substorm. The aurora developed into a double oval configuration, consisting of a set of discrete poleward forms and a separate diffuse auroral oval equatorwards. Although IMF Bz was negative, considerable activity could be seen poleward of the high latitude arcs in the polar cap region. The optical signature of precipitating protons showed that the proton aurora was on the equatorward side of the diffuse aurora and there was a lack of intense energetic proton fluxes in the poleward arcs. A simultaneous FAST pass provided a diagnostic of the particle types in the various regions. These data showed that lower intensity protons were present throughout the entire double oval configuration but with insufficient intensity to produce aurora that could be observed by IMAGE. The FAST data also showed that the bright poleward discrete arcs were accelerated by electrostatic processes, and the wave accelerated electrons were located on the poleward edge of these features.

  3. Proton Radiobiology

    PubMed Central

    Tommasino, Francesco; Durante, Marco

    2015-01-01

    In addition to the physical advantages (Bragg peak), the use of charged particles in cancer therapy can be associated with distinct biological effects compared to X-rays. While heavy ions (densely ionizing radiation) are known to have an energy- and charge-dependent increased Relative Biological Effectiveness (RBE), protons should not be very different from sparsely ionizing photons. A slightly increased biological effectiveness is taken into account in proton treatment planning by assuming a fixed RBE of 1.1 for the whole radiation field. However, data emerging from recent studies suggest that, for several end points of clinical relevance, the biological response is differentially modulated by protons compared to photons. In parallel, research in the field of medical physics highlighted how variations in RBE that are currently neglected might actually result in deposition of significant doses in healthy organs. This seems to be relevant in particular for normal tissues in the entrance region and for organs at risk close behind the tumor. All these aspects will be considered and discussed in this review, highlighting how a re-discussion of the role of a variable RBE in proton therapy might be well-timed. PMID:25686476

  4. Proton geriatrics

    NASA Astrophysics Data System (ADS)

    Kephart, Thomas W.; Nakagawa, Norio

    1984-07-01

    An SO(10) model with particle spectrum and low energy gauge group identical to that of minimal SU (5) below MX but with a nonstandard charge assignment is shown to agree with the experimental best value of sin2θw(Mw) and the lower bound on the proton lifetime.

  5. Technological Advances in Proton Therapy

    NASA Astrophysics Data System (ADS)

    McDonough, James

    2008-03-01

    Proton therapy has interested radiation oncologists since the 1946 paper by Robert R. Wilson describing the energy deposition of proton beams and suggesting it would be more suitable for radiation treatments than beams of x-rays. For all its proposed benefits, only 25,000 or so cancer patients worldwide have been treated with high-energy proton beams over the last fifty years. However, during the past decade that number has started to rapidly increase. In the United States alone the number of dedicated facilities has grown from two to five in the last three years and will likely double again by the end of the current decade. We will soon be treating as many patients in one year as was treated during the first fifty years of proton therapy. Surprisingly, the reason is because of what has been happening in x-ray radiotherapy. Conventional radiotherapy underwent a dramatic change during the past decade with the introduction of multiple advances in imaging technology and beam delivery methods. The imaging advances include both imaging for treatment planning (multislice CT systems, high resolution MRI, and increasing use of PET) and imaging of the target location in the treatment room. The treatment delivery advances, dominated by methods that permit intensity modulated beam delivery, were made possible by increased computational power and more computer control of the treatment delivery. These imaging and beam delivery advances should benefit proton therapy treatments even more than x-ray treatments because of the better conformation of dose to the target that one can achieve with proton beams. However, because of the small size of the proton therapy community it has had difficulty implementing some of the advances made in x-ray therapy. The treatment planning imaging is also used by proton therapy but the on-treatment imaging and the intensity modulation often must be specially developed for each proton therapy system. This talk will present the developments in these areas that are expected to be implemented in the next few years.

  6. Proton maser

    NASA Astrophysics Data System (ADS)

    Ensley, D. L.

    1988-01-01

    New calculations are reported which confirm the ability of an a priori random, initial-phase proton beam to drive a simple, single-stage microwave cavity maser or transit-time oscillator (TTO) to saturation conversion efficiencies of about 11 percent. The required initial TE(011) mode field can be provided from beam ramp-up bandwidth of excitation to a low level from an external source. A saturation field of 45 tesla and output power of 0.2 TW are calculated using an electron insulation field of 10 tesla and a 3 MeV, 400 Ka/sq cm beam. Results are compared to those for an electron beam of the same energy and geometry, and it is shown that proton beams potentially can provide a three order of magnitude increase in overall microwave power production density over that obtainable from electron beam TTOs.

  7. An image-based skeletal model for the ICRP reference adult malespecific absorbed fractions for neutron-generated recoil protons

    NASA Astrophysics Data System (ADS)

    Jokisch, D. W.; Rajon, D. A.; Bahadori, A. A.; Bolch, W. E.

    2011-11-01

    Recoiling hydrogen nuclei are a principle mechanism for energy deposition from incident neutrons. For neutrons incident on the human skeleton, the small sizes of two contrasting media (trabecular bone and marrow) present unique problems due to a lack of charged-particle (protons) equilibrium. Specific absorbed fractions have been computed for protons originating in the human skeletal tissues for use in computing neutron dose response functions. The proton specific absorbed fractions were computed using a pathlength-based range-energy calculation in trabecular skeletal samples of a 40 year old male cadaver.

  8. An image-based skeletal model for the ICRP reference adult male-specific absorbed fractions for neutron-generated recoil protons.

    PubMed

    Jokisch, D W; Rajon, D A; Bahadori, A A; Bolch, W E

    2011-11-01

    Recoiling hydrogen nuclei are a principle mechanism for energy deposition from incident neutrons. For neutrons incident on the human skeleton, the small sizes of two contrasting media (trabecular bone and marrow) present unique problems due to a lack of charged-particle (protons) equilibrium. Specific absorbed fractions have been computed for protons originating in the human skeletal tissues for use in computing neutron dose response functions. The proton specific absorbed fractions were computed using a pathlength-based range-energy calculation in trabecular skeletal samples of a 40 year old male cadaver. PMID:21983482

  9. ADVANCED MAGNETIC RESONANCE IMAGING OF CEREBRAL CAVERNOUS MALFORMATIONS: I. HIGH FIELD IMAGING OF EXCISED HUMAN LESIONS

    PubMed Central

    Shenkar, Robert; Venkatasubramanian, Palamadai N.; Zhao, Jin-cheng; Batjer, H. Hunt; Wyrwicz, Alice M.; Awad, Issam A.

    2008-01-01

    Objectives We hypothesized that structural details would be revealed in cerebral cavernous malformations (CCMs) through the use of high field magnetic resonance (MR) and confocal microscopy, which have not been described previously. The structural details of CCMs excised from human patients were sought by examination with high field MR imaging, and correlated with confocal microscopy of the same specimens. Novel features of CCM structure are outlined, including methodological limitations, venues for future research and possible clinical implications. Methods CCM lesions excised from four patients were fixed in 2% paraformaldehyde and subjected to high resolution MR imaging at 9.4 or 14.1 Tesla by spin-echo and gradient recalled echo methods. Histological validation of angioarchitecture was conducted on thick sections of CCM lesions using fluorescent probes to endothelium under confocal microscopy. Results Images of excised human CCM lesions were acquired with proton density-weighted, T1-weighted, T2-weighted spin echo and T2*-weighted gradient-recalled echo MR. These images revealed large bland regions with thin walled caverns, and honeycombed regions with notable capillary proliferation and smaller caverns surrounding larger caverns. Proliferating capillaries and caverns of various sizes were also associated with the wall of apparent larger blood vessels in the lesions. Similar features were confirmed within thick sections of CCMs by confocal microscopy. MR relaxation times in different regions of interest suggested the presence of different states of blood breakdown products in areas with apparent angiogenic proliferative activity. Conclusions The high field MR imaging techniques demonstrate novel features of CCM angioarchitecture, visible at near histological resolution, including regions with apparently different biologic activity. These preliminary observations will motivate future research, correlating lesion biologic and clinical activity with features of MR imaging at higher field strength. PMID:18981890

  10. Ex vivo differential phase contrast and magnetic resonance imaging for characterization of human carotid atherosclerotic plaques.

    PubMed

    Meletta, Romana; Borel, Nicole; Stolzmann, Paul; Astolfo, Alberto; Klohs, Jan; Stampanoni, Marco; Rudin, Markus; Schibli, Roger; Krmer, Stefanie D; Herde, Adrienne Mller

    2015-10-01

    Non-invasive detection of specific atherosclerotic plaque components related to vulnerability is of high clinical relevance to prevent cerebrovascular events. The feasibility of magnetic resonance imaging (MRI) for characterization of plaque components was already demonstrated. We aimed to evaluate the potential of ex vivo differential phase contrast X-ray tomography (DPC) to accurately characterize human carotid plaque components in comparison to high field multicontrast MRI and histopathology. Two human plaque segments, obtained from carotid endarterectomy, classified according to criteria of the American Heart Association as stable and unstable plaque, were examined by ex vivo DPC tomography and multicontrast MRI (T1-, T2-, and proton density-weighted imaging, magnetization transfer contrast, diffusion-weighted imaging). To identify specific plaque components, the plaques were subsequently sectioned and stained for fibrous and cellular components, smooth muscle cells, hemosiderin, and fibrin. Histological data were then matched with DPC and MR images to define signal criteria for atherosclerotic plaque components. Characteristic structures, such as the lipid and necrotic core covered by a fibrous cap, calcification and hemosiderin deposits were delineated by histology and found with excellent sensitivity, resolution and accuracy in both imaging modalities. DPC tomography was superior to MRI regarding resolution and soft tissue contrast. Ex vivo DPC tomography allowed accurate identification of structures and components of atherosclerotic plaques at different lesion stages, in good correlation with histopathological findings. PMID:26179860

  11. Influence of permittivity and electrical conductivity on image pattern of MRI.

    PubMed

    Harimoto, Takashi; Ohno, Seiichiro; Hattori, Kengo; Hirosue, Miyuki; Miyai, Masahiro; Shibuya, Koichi; Kuroda, Masahiro; Kanazawa, Susumu; Kato, Hirokazu

    2013-01-01

    In proton density-weighted (PDW) MR imaging, the patterns of signal intensity vary depending on the imaged material, and change with the flip angle (FA) applied to the imaged material. The correlation between the pre-determined FA and the actual FA applied to imaged objects was investigated using 4 types of phantoms having different dielectric properties. PDW images were acquired using the spin-echo (SE) method and different pre-determined FA. Dependency of the signal intensity distribution in the phantom on the pre-determined FA differed among phantoms: patterns for water and 0.402 w/w% saline solution phantoms changed with the pre-determined FA, whereas those for olive oil and 4.02 w/w% saline solution phantoms were barely affected by the pre-determined FA. Causes of these phenomena were considered to be the differences between the pre-determined FA and the actual FA among the phantoms; differences were also influenced by the positioning of the phantom. Our study showed that the actual FA in the phantom is greater than the pre-determined FA in high permittivity media, whereas it is reduced by an increased conductivity of the media. PMID:23694908

  12. Proton scaling

    SciTech Connect

    Canavan, Gregory H

    2009-01-01

    This note presents analytic estimates of the performance of proton beams in remote surveillance for nuclear materials. The analysis partitions the analysis into the eight steps used by a companion note: (1) Air scattering, (2) Neutron production in the ship and cargo, (3) Target detection probability, (4) Signal produced by target, (5) Attenuation of signal by ship and cargo, (6) Attenuation of signal by air, (7) Geometric dilution, and (8) Detector Efficiency. The above analyses indicate that the dominant air scattering and loss mechanisms for particle remote sensing are calculable with reliable and accepted tools. They make it clear that the conversion of proton beams into neutron sources rapidly goes to completion in all but thinnest targets, which means that proton interrogation is for all purposes executed by neutrons. Diffusion models and limiting approximations to them are simple and credible - apart from uncertainty over the cross sections to be used in them - and uncertainty over the structure of the vessels investigated. Multiplication is essentially unknown, in part because it depends on the details of the target and its shielding, which are unlikely to be known in advance. Attenuation of neutron fluxes on the way out are more complicated due to geometry, the spectrum of fission neutrons, and the details of their slowing down during egress. The attenuation by air is large but less uncertain. Detectors and technology are better known. The overall convolution of these effects lead to large but arguably tolerable levels of attenuation of input beams and output signals. That is particularly the case for small, mobile sensors, which can more than compensate for size with proximity to operate reliably while remaining below flux limits. Overall, the estimates used here appear to be of adequate accuracy for decisions. That assessment is strengthened by their agreement with companion calculations.

  13. Development of Proton Computed Tomography for Applications in Proton Therapy

    NASA Astrophysics Data System (ADS)

    Bashkirov, Vladimir; Schulte, Reinhard; Coutrakon, George; Erdelyi, Bela; Wong, Kent; Sadrozinski, Hartmut; Penfold, Scott; Rosenfeld, Anatoly; McAllister, Scott; Schubert, Keith

    2009-03-01

    Determination of the Bragg peak position in proton therapy requires accurate knowledge of the electron density and ratio of effective atomic number and mass (Z/A) of the body tissues traversed. While the Z/A ratio is fairly constant for human tissues, the density of tissues varies significantly. One possibility to obtain accurate electron density information of tissues is to use protons of sufficient energy to penetrate the patient and measure their energy loss. From these transmission measurements, it is possible to reconstruct a three-dimensional map of electron densities using algebraic techniques. The interest in proton computed tomography (pCT) has considerably increased in recent years due to the more common use of proton accelerators for cancer treatment world-wide and a modern design concept based on current high-energy physics technology has been suggested. This contribution gives a status update on the pCT project carried out by the pCT Collaboration, a group of institutions sharing interest and expertise in the development of pCT. We will present updated imaging data obtained with a small pCT prototype developed in collaboration with the Santa Cruz Institute of Particle Physics and installed on the proton research beam line at Loma Linda University Medical Center. We will discuss hardware decisions regarding the next-generation pCT scanner, which will permit scanning of head-sized objects. Progress has also been made in the formulation of the most likely path of protons through an object and parallelizable iterative reconstruction algorithms that can be implemented on general-purpose commodity graphics processing units. Finally, we will present simulation studies for utilizing pCT technology for on-line proton dose verification and tumor imaging with positron emission tomography (PET).

  14. π Echo-Planar Imaging with concomitant field compensation for porous media MRI.

    PubMed

    Xiao, Dan; Balcom, Bruce J

    2015-11-01

    The π Echo Planar Imaging (PEPI) method was modified to compensate for concomitant magnetic fields by waveform symmetrization. Samples with very short T2(∗) (a few hundred microseconds) and short T2 (tens of milliseconds to hundreds of milliseconds) were investigated. Echo spacings as short as 1.2 ms were achieved with the gradient pre-equalization method, enabling rapid 3D imaging of short relaxation time species with sub-millimeter resolution. The PEPI method yields superior quality images, compared to the Fast Spin Echo (FSE) method, with significantly reduced gradient duty cycle. Accelerated PEPI measurements with a variable number of centric interleaves are presented. Restricted k-space sampling was demonstrated for specific sample geometries, notably a Locharbriggs sandstone core plug, with the acquisition time further reduced. These methods generate proton density weighted images considering the echo time to sample T2 ratio. These methods are principally designed for 3D studies of fluid saturation in rock core plugs, evolving in time due to some manner of external perturbation, such as water flooding. PMID:26398928

  15. π Echo-Planar Imaging with concomitant field compensation for porous media MRI

    NASA Astrophysics Data System (ADS)

    Xiao, Dan; Balcom, Bruce J.

    2015-11-01

    The π Echo Planar Imaging (PEPI) method was modified to compensate for concomitant magnetic fields by waveform symmetrization. Samples with very short T2∗ (a few hundred microseconds) and short T2 (tens of milliseconds to hundreds of milliseconds) were investigated. Echo spacings as short as 1.2 ms were achieved with the gradient pre-equalization method, enabling rapid 3D imaging of short relaxation time species with sub-millimeter resolution. The PEPI method yields superior quality images, compared to the Fast Spin Echo (FSE) method, with significantly reduced gradient duty cycle. Accelerated PEPI measurements with a variable number of centric interleaves are presented. Restricted k-space sampling was demonstrated for specific sample geometries, notably a Locharbriggs sandstone core plug, with the acquisition time further reduced. These methods generate proton density weighted images considering the echo time to sample T2 ratio. These methods are principally designed for 3D studies of fluid saturation in rock core plugs, evolving in time due to some manner of external perturbation, such as water flooding.

  16. Proton Therapy

    MedlinePLUS

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  17. Electron and Proton Auroral Dynamics

    NASA Technical Reports Server (NTRS)

    Mende, S. B.; Frey, H. U.; Gerard, J. C.; Hubert, B.; Fuselier, S.; Spann, J. F., Jr.; Gladstone, R.; Burch, J. L.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Data from the Wide-band Imaging Camera (WIC) sensitive to far ultraviolet auroras and from the Spectrographic Imager (SI) channel SI12, sensitive to proton precipitation induced Lyman alpha were analyzed during a high altitude orbit segment of the IMAGE spacecraft. This segment began during the expansive phase of a substorm. The aurora changed into a double oval configuration, consisting of a set of discrete pole-ward forms and a separate diffuse auroral oval equatorwards, Although IMF Bz was strongly southward considerable activity could be seen poleward of the discrete auroras in the region that was considered to be the polar cap. The SI12 Doppler shifted Lyman alpha signature of precipitating protons show that the proton aurora is on the equatorward side of the diffuse aurora. In the following several hours the IMF Bz field changed signed. Although the general character of the proton and electron aurora did not change, the dayside aurora moved equatorward when the Bz was negative and more bright aurora was seen in the central polar cap during periods of positive Bz.

  18. Evaluation of the susceptibility artifacts and tissue injury caused by implanted microchips in dogs on 1.5 T magnetic resonance imaging.

    PubMed

    Saito, Miyoko; Ono, Shin; Kayanuma, Hideki; Honnami, Muneki; Muto, Makoto; Une, Yumi

    2010-05-01

    Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. The purpose of this study was to investigate these complications in dogs with implanted microchips by evaluating MR images and the histopathological changes after 1.5 Tesla (T) MRI. Five dogs underwent microchip implantation in the cervicothoracic area. One month later, the area was imaged using 1.5T MRI in three dogs. The microchips were removed surgically together with the surrounding tissue in all dogs. There was significant signal loss and image distortion over a wide range around the area where the microchip was implanted. This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. The artifact was more extensive in T2*-weighted images (gradient-echo) and less extensive in proton density-weighted images (fast spin-echo with short echo time). Histopathologically, all microchips were well-encapsulated with granulation tissue, and there were no evidence of migration of microchips. Cell debris and a moderate number of degenerated cells with fibrin were seen in the inner layer of the granulation tissue in each dog that underwent MRI. These changes were very subtle and did not seem to be clinically significant. The results of this study suggest that, in 1.5T MRI, susceptibility artifacts produced by implanted microchips can be marked, although the dogs with implants appeared to be scanned safely. PMID:20086326

  19. Magnetic Resonance Imaging of Subchondral Bone Marrow Lesions in Association with Osteoarthritis

    PubMed Central

    Xu, Li; Hayashi, Daichi; Roemer, Frank W.; Felson, David T.; Guermazi, Ali

    2013-01-01

    Objectives This nonsystematic literature review provides an overview of magnetic resonance imaging (MRI) of subchondral bone marrow lesions (BMLs) in association with osteoarthritis (OA), with particular attention to the selection of MRI sequences and semiquantitative scoring systems, characteristic morphology, and differential diagnosis. Histologic basis, natural history, and clinical significance are also briefly discussed. Methods PubMed was searched for articles published up to 2011, using the keywords bone marrow lesion, osteoarthritis, magnetic resonance imaging, bone marrow edema, histology, pain, and subchondral. Results BMLs in association with OA correspond to fibrosis, necrosis, edema, and bleeding of fatty marrow as well as abnormal trabeculae on histopathology. Lesions may fluctuate in size within a short time and are associated with the progression of articular cartilage loss and fluctuation of pain in knee OA. The characteristic subchondral edema-like signal intensity of BMLs should be assessed using T2-weighted, proton density-weighted, intermediate-weighted fat-suppressed fast spin echo or short tau inversion recovery. Several semiquantitative scoring systems are available to characterize and grade the severity of BMLs. Quantitative approaches have also been introduced. Differential diagnoses of degenerative BMLs include a variety of traumatic or nontraumatic pathologies that may appear similar to OA-related BMLs on MRI. Conclusions Subchondral BMLs are a common imaging feature of OA with clinical significance and typical signal alteration patterns, which can be assessed and graded by semiquantitative scoring systems using sensitive MRI sequences. PMID:22542276

  20. Synchrotron based proton drivers

    SciTech Connect

    Weiren Chou

    2002-09-19

    Proton drivers are the proton sources that produce intense short proton bunches. They have a wide range of applications. This paper discusses the proton drivers based on high-intensity proton synchrotrons. It gives a review of the high-intensity proton sources over the world and a brief report on recent developments in this field in the U.S. high-energy physics (HEP) community. The Fermilab Proton Driver is used as a case study for a number of challenging technical design issues.

  1. Measurement of pion, kaon and proton production in proton-proton collisions at TeV

    NASA Astrophysics Data System (ADS)

    Adam, J.; Adamov, D.; Aggarwal, M. M.; Rinella, G. Aglieri; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmed, I.; Ahn, S. U.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Molina, R. Alfaro; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Prado, C. Alves Garcia; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Anti?i?, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Azmi, M. D.; Bach, M.; Badal, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Ball, M.; Pedrosa, F. Baltasar Dos Santos; Baral, R. C.; Barbano, A. M.; Barbera, R.; Barile, F.; Barnafldi, G. G.; Barnby, L. S.; Barret, V.; Bartalini, P.; Bartke, J.; Bartsch, E.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Camejo, A. Batista; Batyunya, B.; Batzing, P. C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Martinez, H. Bello; Bellwied, R.; Belmont, R.; Belmont-Moreno, E.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Biel?k, J.; Biel?kov, J.; Bilandzic, A.; Biswas, S.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bggild, H.; Boldizsr, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Borri, M.; Boss, F.; Botje, M.; Botta, E.; Bttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Brucken, E. J.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Buxton, J. T.; Caffarri, D.; Cai, X.; Caines, H.; Diaz, L. Calero; Caliva, A.; Villar, E. Calvo; Camerini, P.; Carena, F.; Carena, W.; Castellanos, J. Castillo; Castro, A. J.; Casula, E. A. R.; Cavicchioli, C.; Sanchez, C. Ceballos; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Chartier, M.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Barroso, V. Chibante; Chinellato, D. D.; Chochula, P.; Choi, K.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Balbastre, G. Conesa; Valle, Z. Conesa del; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Morales, Y. Corrales; Maldonado, I. Corts; Cortese, P.; Cosentino, M. R.; Costa, F.; Crochet, P.; Albino, R. Cruz; Cuautle, E.; Cunqueiro, L.; Dahms, T.; Dainese, A.; Danu, A.; Das, D.; Das, I.; Das, S.; Dash, A.; Dash, S.; De, S.; Caro, A. De; Cataldo, G. de; Cuveland, J. de; Falco, A. De; Gruttola, D. De; Marco, N. De; Pasquale, S. De; Deisting, A.; Deloff, A.; Dnes, E.; D'Erasmo, G.; Bari, D. Di; Mauro, A. Di; Nezza, P. Di; Corchero, M. A. Diaz; Dietel, T.; Dillenseger, P.; Divi, R.; Djuvsland, .; Dobrin, A.; Dobrowolski, T.; Gimenez, D. Domenicis; Dnigus, B.; Dordic, O.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erhardt, F.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Eum, J.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabbietti, L.; Fabris, D.; Faivre, J.; Fantoni, A.; Fasel, M.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Tllez, A. Fernndez; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Fleck, M. G.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Girard, M. Fusco; Gaardhje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Gasik, P.; Germain, M.; Gheata, A.; Gheata, M.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Giubilato, P.; Dziadus, E. Gladysz; Glssel, P.; Ramirez, A. Gomez; Zamora, P. Gonzlez; Gorbunov, S.; Grlich, L.; Gotovac, S.; Grabski, V.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J.-Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, .; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Corral, G. Herrera; Hess, B. A.; Hetland, K. F.; Hilden, T. E.; Hillemanns, H.; Hippolyte, B.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hussain, T.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Izucheev, V.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H. S. Y.; Jena, C.; Jena, S.; Bustamante, R. T. Jimenez; Jones, P. G.; Jung, H.; Jusko, A.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Uysal, A. Karasu; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L. D.; Keil, M.; Khan, K. H.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, H.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, C.; Klein, J.; Klein-Bsing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobayashi, T.; Kobdaj, C.; Kofarago, M.; Khler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Kondratyuk, E.; Konevskikh, A.; Kouzinopoulos, C.; Kovalenko, O.; Kovalenko, V.; Kowalski, M.; Kox, S.; Meethaleveedu, G. Koyithatta; Kral, J.; Krlik, I.; Krav?kov, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kubera, A. M.; Ku?era, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kumar, L.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Pointe, S. L. La; Rocca, P. La; Fernandes, C. Lagana; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; Laudi, E.; Lea, R.; Leardini, L.; Lee, G. R.; Lee, S.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Monzn, I. Len; Leoncino, M.; Lvai, P.; Li, S.; Li, X.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Loizides, C.; Lopez, X.; Torres, E. Lpez; Lowe, A.; Lu, X.-G.; Luettig, P.; Lunardon, M.; Luparello, G.; Maevskaya, A.; Mager, M.; Mahajan, S.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Cervantes, I. Maldonado; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mare, J.; Margagliotti, G. V.; Margotti, A.; Margutti, J.; Marn, A.; Markert, C.; Marquard, M.; Martin, N. A.; Blanco, J. Martin; Martinengo, P.; Martnez, M. I.; Martnez Garca, G.; Pedreira, M. Martinez; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Masui, H.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Mcdonald, D.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Prez, J. Mercado; Meres, M.; Miake, Y.; Mieskolainen, M. M.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Minervini, L. M.; Mischke, A.; Mishra, A. N.; Mi?kowiec, D.; Mitra, J.; Mitu, C. M.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Zetina, L. Montao; Montes, E.; Morando, M.; Godoy, D. A. Moreira De; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mhlheim, D.; Muhuri, S.; Mukherjee, M.; Mller, H.; Mulligan, J. D.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Naru, M. U.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nellen, L.; Ng, F.; Nicassio, M.; Niculescu, M.; Niedziela, J.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Ohlson, A.; Okatan, A.; Okubo, T.; Olah, L.; Oleniacz, J.; Silva, A. C. Oliveira Da; Oliver, M. H.; Onderwaater, J.; Oppedisano, C.; Velasquez, A. Ortiz; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Pachmayer, Y.; Pagano, P.; Pai?, G.; Pajares, C.; Pal, S. K.; Pan, J.; Pandey, A. K.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Costa, H. Pereira Da; Filho, E. Pereira De Oliveira; Peresunko, D.; Lara, C. E. Prez; Peskov, V.; Pestov, Y.; Petr?ek, V.; Petrov, V.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; P?osko?, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L. M.; Poghosyan, M. G.; Polichtchouk, B.; Poljak, N.; Poonsawat, W.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Pospisil, J.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puccio, M.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rajput, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Rsnen, S. S.; Rascanu, B. T.; Rathee, D.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Ren, X.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J.-P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Ristea, C.; Rivetti, A.; Rocco, E.; Cahuantzi, M. Rodrguez; Manso, A. Rodriguez; Red, K.; Rogochaya, E.; Rohr, D.; Rhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Montero, A. J. Rubio; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; afa?k, K.; Sahlmuller, B.; Sahoo, P.; Sahoo, R.; Sahoo, S.; Sahu, P. K.; Saini, J.; Sakai, S.; Saleh, M. A.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Castro, X. Sanchez; ndor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Seeder, K. S.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Senosi, K.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabanov, A.; Shabetai, A.; Shadura, O.; Shahoyan, R.; Shangaraev, A.; Sharma, A.; Sharma, N.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Sielewicz, K. M.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Slupecki, M.; Smirnov, N.; Snellings, R. J. M.; Snellman, T. W.; Sgaard, C.; Soltz, R.; Song, J.; Song, M.; Song, Z.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Stassinaki, M. Spyropoulou; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Strmen, P.; Suaide, A. A. P.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; umbera, M.; Symons, T. J. M.; Szabo, A.; Toledo, A. Szanto de; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tanaka, N.; Tangaro, M. A.; Takaki, J. D. Tapia; Peloni, A. Tarantola; Tariq, M.; Tarzila, M. G.; Tauro, A.; Muoz, G. Tejeda; Telesca, A.; Terasaki, K.; Terrevoli, C.; Teyssier, B.; Thder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trogolo, S.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Utrobicic, A.; Vajzer, M.; Vala, M.; Palomo, L. Valencia; Vallero, S.; Maarel, J. Van Der; Hoorne, J. W. Van; Leeuwen, M. van; Vanat, T.; Vyvre, P. Vande; Varga, D.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vauthier, A.; Vechernin, V.; Veen, A. M.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Limn, S. Vergara; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Baillie, O. Villalobos; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Vislavicius, V.; Viyogi, Y. P.; Vodopyanov, A.; Vlkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; Haller, B. von; Vorobyev, I.; Vranic, D.; Vrlkov, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wang, H.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Weber, S. G.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C. S.; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yano, S.; Yasnopolskiy, S.; Yin, Z.; Yokoyama, H.; Yoo, I.-K.; Yurchenko, V.; Yushmanov, I.; Zaborowska, A.; Zaccolo, V.; Zaman, A.; Zampolli, C.; Zanoli, H. J. C.; Zaporozhets, S.; Zarochentsev, A.; Zvada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, Y.; Zhou, Z.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zyzak, M.

    2015-05-01

    The measurement of primary , , and production at mid-rapidity ( 0.5) in proton-proton collisions at 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/ for pions, from 0.2 up to 6 GeV/ for kaons and from 0.3 up to 6 GeV/ for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

  2. Images

    Cancer.gov

    Home News and Events Multimedia Library Images Images: Cancer Biology Image:Cell with DNA72 DPI|300 DPIDrawing depicting DNA molecule unwinding from a chromosome inside the nucleus of a cell. NHGRI>>View All Cancer Pathology/Imaging Image:Female

  3. Proton Therapy - Accelerating Protons to Save Lives

    SciTech Connect

    Keppel, Cynthia

    2011-10-25

    In 1946, physicist Robert Wilson first suggested that protons could be used as a form of radiation therapy in the treatment of cancer because of the sharp drop-off that occurs on the distal edge of the radiation dose. Research soon confirmed that high-energy protons were particularly suitable for treating tumors near critical structures, such as the heart and spinal column. The precision with which protons can be delivered means that more radiation can be deposited into the tumor while the surrounding healthy tissue receives substantially less or, in some cases, no radiation. Since these times, particle accelerators have continuously been used in cancer therapy and today new facilities specifically designed for proton therapy are being built in many countries. Proton therapy has been hailed as a revolutionary cancer treatment, with higher cure rates and fewer side effects than traditional X-ray photon radiation therapy. Proton therapy is the modality of choice for treating certain small tumors of the eye, head or neck. Because it exposes less of the tissue surrounding a tumor to the dosage, proton therapy lowers the risk of secondary cancers later in life - especially important for young children. To date, over 80,000 patients worldwide have been treated with protons. Currently, there are nine proton radiation therapy facilities operating in the United States, one at the Hampton University Proton Therapy Institute. An overview of the treatment technology and this new center will be presented.

  4. Proton aurora related to intervals of pulsations of diminishing periods

    NASA Astrophysics Data System (ADS)

    Yahnin, A. G.; Yahnina, T. A.; Frey, H. U.; Bsinger, T.; Manninen, J.

    2009-12-01

    Geomagnetic pulsations in the Pc1 frequency range are believed to be an indicator of electromagnetic ion cyclotron waves arriving from the equatorial magnetosphere, where the waves are generated because of a cyclotron instability of the anisotropic distribution of ring current ions. Proton precipitation produced by the cyclotron instability can be responsible for proton aurora. Indeed, the relationship between some types of proton aurora (proton spots and proton flashes) and pulsations in the Pc1 range (quasi-monochromatic Pc1 and Pc1 bursts) has already been found. The aim of this study is to find the proton aurora pattern, which relates to the kind of geomagnetic pulsations in the Pc1 range called intervals of pulsation of diminishing periods (IPDP). This is done on the basis of 2 year observations of geomagnetic pulsations at the Finnish meridional network of search coil magnetometers and proton aurora from the IMAGE spacecraft. We found that during IPDP the proton arcs appear equatorward of the proton oval at the meridian of the ground magnetometers. The maximum intensity of the pulsations is observed at the ground station, which is closest to the proton arc. The proton arcs tend to appear at lower latitudes at later magnetic local times (MLTs). This agrees with the facts that the IPDP occurrence exhibits a similar behavior and that the IPDP end frequency tends to increase with increasing MLT. In addition, data from geosynchronous spacecraft showed that IPDP occur when clouds of energy-dispersed energetic protons pass through the meridian of the ground magnetometers. The spatial-temporal correlation of IPDP with proton aurora arcs confirms the expectation that the proton arcs, like the proton spots and flashes, are the ionospheric image of the region where the ion cyclotron instability develops in the equatorial magnetosphere. In the case of IPDP the instability develops when drifting proton clouds resulting from particle injections in the night sector contact the plasmaspheric plume onto which the proton arcs map.

  5. SU-E-J-244: Validation of a 6D-Robotic-Couch and Image Guidance Radiation Therapy (IGRT) System for Localization in World's First Single-Room Proton Therapy System

    SciTech Connect

    Rankine, L; Klein, E; Grantham, K; Goddu, S; Cessac, R; Baker, K; Santanam, L

    2014-06-01

    Purpose: The Mevion S250 proton therapy unit is equipped with a 6D-robotic couch and IGRT system (Verity). The patient alignment process allows corrections in six degrees of freedom: translation (x,y,z), pitch, roll, and yaw (θ,ϑ,ψ). Geometric accuracy of couch corrections and imaging vs. radiation isocenter coincidence were quantified before clinical implementation. Methods: A commercial phantom with sixteen 2mm tungsten BBs was rigidly couch-mounted and imaged with CT. Seventeen rigid translations/rotations of known magnitude were digitally applied to the original CT image using commercial software, validated with Varian OBI system. For each altered image, phantom was mounted on robotic couch in original position, then Verity 2D:2D match (PA-LLAT) was performed using DRRs from altered images. Corrections were recorded and applied, phantom was imaged a second time and residual corrections recorded. Physical measurements verified that applied couch corrections coincided with both physical couch shifts/rotations and known CT image translations/rotations. Additionally, image vs. radiation isocenter coicidence was quantified over couch treatment angles (±90° from setup position) using radiochromic film and an image-guided couch star-shot. Posterior-anterior and left-lateral kV radiographs were taken before each beam was delivered to verify imaging/radiation isocentricity. Results: Verity suggested couch corrections and known CT shifts/rotations agreed within ±1mm (average: Δ lat=0.5mm; Δ vert=0.4mm; Δ long=0.3mm) and ± 0.4° (average: Δ pitch=0.24° Δ roll=0.01°; Δ yaw=0.10°). Physical couch measurements and Verity applied corrections agreed within ± 1mm (average: Δlat=0.5mm; Δvert=0.4mm; Δlong=0.2mm) and ±0.2° (average: Δpitch=0.03°; Δ roll=0.04°; Δ yaw=0.04°). The directionality of all translations and rotations were qualitatively verified. The image vs. radiation isocenter coincidence was <1mm and radiation-isocenter precision was <1mm over the 180° of couch motion, as indicated by film analysis. Conclusion: The Verity IGRT software and 6D-couch combination on the Mevion S250 was verified as accurate within 1mm and 0.5°. This complies with the TG-142 standards for a stereotactic radiotherapy IGRT system. Rob Cessac is employed as Product Manager for Mevion Medical Systems.

  6. Proton Therapy for Thoracoabdominal Tumors

    NASA Astrophysics Data System (ADS)

    Sakurai, Hideyuki; Okumura, Toshiyuki; Sugahara, Shinji; Nakayama, Hidetsugu; Tokuuye, Koichi

    In advanced-stage disease of certain thoracoabdominal tumors, proton therapy (PT) with concurrent chemotherapy may be an option to reduce side effects. Several technological developments, including a respiratory gating system and implantation of fiducial markers for image guided radiation therapy (IGRT), are necessary for the treatment in thoracoabdominal tumors. In this chapter, the role of PT for tumors of the lung, the esophagus, and liver are discussed.

  7. A 3T Sodium and Proton Composite Array Breast Coil

    PubMed Central

    Kaggie, Joshua D.; Hadley, J. Rock; Badal, James; Campbell, John R.; Park, Daniel J.; Parker, Dennis L.; Morrell, Glen; Newbould, Rexford D.; Wood, Ali F.; Bangerter, Neal K.

    2013-01-01

    Purpose The objective of this study was to determine whether a sodium phased array would improve sodium breast MRI at 3T. The secondary objective was to create acceptable proton images with the sodium phased array in place. Methods A novel composite array for combined proton/sodium 3T breast MRI is compared to a coil with a single proton and sodium channel. The composite array consists of a 7-channel sodium receive array, a larger sodium transmit coil, and a 4-channel proton transceive array. The new composite array design utilizes smaller sodium receive loops than typically used in sodium imaging, uses novel decoupling methods between the receive loops and transmit loops, and uses a novel multi-channel proton transceive coil. The proton transceive coil reduces coupling between proton and sodium elements by intersecting the constituent loops to reduce their mutual inductance. The coil used for comparison consists of a concentric sodium and proton loop with passive decoupling traps. Results The composite array coil demonstrates a 25x improvement in SNR for sodium imaging and similar SNR for proton imaging when compared to a simple single-loop dual resonant design. Conclusion The improved SNR of the composite array gives breast sodium images of unprecedented quality in reasonable scan times. PMID:24105740

  8. -delayed proton emission branches in 43Cr

    SciTech Connect

    Pomorski, M.; Miernik, K.; Dominik, W.; Janas, Z.; Pfutzner, M.; Bingham, C. R.; Czyrkowski, H.; Cwiok, Mikolaj; Darby, Iain; Dabrowski, Ryszard; Ginter, T. N.; Grzywacz, Robert Kazimierz; Karny, M.; Korgul, A.; Kusmierz, W.; Liddick, Sean; Rajabali, M. M.; Rykaczewski, Krzysztof Piotr; Stolz, A.

    2011-01-01

    The + decay of very neutron-deficient 43Cr was studied by means of an imaging time projection chamber that allowed recording tracks of charged particles. Events of -delayed emission of one, two, and three protons were clearly identified. The absolute branching ratios for these channels were determined to be (81 4)%, (7.1 0.4)%, and (0.08 0.03)%, respectively. 43Cr is thus established as the second case in which the -3p decay occurs. Although the feeding to the proton-bound states in 43V is expected to be negligible, the large branching ratio of (12 4)% for decays without proton emission is found.

  9. Proton shadow camera using CR-39 track detectors

    SciTech Connect

    Stone, G.F.; Ceglio, N.M.

    1983-09-01

    We have developed a capability for imaging proton sources of moderate energy (6 MeV), with moderate spatial resolution (approx. = 9 ..mu..m), as a diagnostic for laser fusion research. Our technique involves the use of Fresnel zone plate coded imaging coupled with nuclear track detectors (CR-39). We report on a series of test experiments in which a zone plate shadow camera successfully produced images of a proton source distribution. The zone plate shadow patterns were optically reconstructed in higher order producing diffraction-limited point response images with FWHM values of approx. = 9 ..mu..m for a 6 MeV proton source.

  10. Elastic proton-proton scattering at RHIC

    SciTech Connect

    Yip, K.

    2011-09-03

    Here we describe elastic proton+proton (p+p) scattering measurements at RHIC in p+p collisions with a special optics run of {beta}* {approx} 21 m at STAR, at the center-of-mass energy {radical}s = 200 GeV during the last week of the RHIC 2009 run. We present preliminary results of single and double spin asymmetries.

  11. What's In a Proton?

    ScienceCinema

    Brookhaven Lab

    2010-01-08

    Physicist Peter Steinberg explains that fundamental particles like protons are themselves made up of still smaller particles called quarks. He discusses how new particles are produced when quarks are liberated from protons...a process that can be observed

  12. What's In a Proton?

    SciTech Connect

    Brookhaven Lab

    2009-07-08

    Physicist Peter Steinberg explains that fundamental particles like protons are themselves made up of still smaller particles called quarks. He discusses how new particles are produced when quarks are liberated from protons...a process that can be observed

  13. Development and evaluation of a short-range applicator for treating superficial moving tumors with respiratory-gated spot-scanning proton therapy using real-time image guidance.

    PubMed

    Matsuura, Taeko; Fujii, Yusuke; Takao, Seishin; Yamada, Takahiro; Matsuzaki, Yuka; Miyamoto, Naoki; Takayanagi, Taisuke; Fujitaka, Shinichiro; Shimizu, Shinichi; Shirato, Hiroki; Umegaki, Kikuo

    2016-02-21

    Treatment of superficial tumors that move with respiration (e.g. lung tumors) using spot-scanning proton therapy (SSPT) is a high-priority research area. The recently developed real-time image-gated proton beam therapy (RGPT) system has proven to be useful for treating moving tumors deep inside the liver. However, when treating superficial tumors, the proton's range is small and so is the sizes of range straggling, making the Bragg-peaks extremely sharp compared to those located in deep-seated tumors. The extreme sharpness of Bragg-peaks is not always beneficial because it necessitates a large number of energy layers to make a spread-out Bragg-peak, resulting in long treatment times, and is vulnerable to motion-induced dose deterioration. We have investigated a method to treat superficial moving tumors in the lung by the development of an applicator compatible with the RGPT system. A mini-ridge filter (MRF) was developed to broaden the pristine Bragg-peak and, accordingly, decrease the number of required energy layers to obtain homogeneous irradiation. The applicator position was designed so that the fiducial marker's trajectory can be monitored by fluoroscopy during proton beam-delivery. The treatment plans for three lung cancer patients were made using the applicator, and four-dimensional (4D) dose calculations for the RGPT were performed using patient respiratory motion data. The effect of the MRF on the dose distributions and treatment time was evaluated. With the MRF, the number of energy layers was decreased to less than half of that needed without it, whereas the target volume coverage values (D99%, D95%, D50%, D2%) changed by less than 1% of the prescribed dose. Almost no dose distortion was observed after the 4D dose calculation, whereas the treatment time decreased by 26%-37%. Therefore, we conclude that the developed applicator compatible with RGPT is useful to solve the issue in the treatment of superficial moving tumors with SSPT. PMID:26815927

  14. Note: A new angle-resolved proton energy spectrometer

    SciTech Connect

    Zheng, Y.; Su, L. N.; Liu, M.; Liu, B. C.; Shen, Z. W.; Fan, H. T.; Li, Y. T.; Chen, L. M.; Lu, X.; Ma, J. L.; Wang, W. M.; Wang, Z. H.; Wei, Z. Y.; Zhang, J.; Key Laboratory for Laser Plasmas and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240

    2013-09-15

    In typical laser-driven proton acceleration experiments Thomson parabola proton spectrometers are used to measure the proton spectra with very small acceptance angle in specific directions. Stacks composed of CR-39 nuclear track detectors, imaging plates, or radiochromic films are used to measure the angular distributions of the proton beams, respectively. In this paper, a new proton spectrometer, which can measure the spectra and angular distributions simultaneously, has been designed. Proton acceleration experiments performed on the Xtreme light III laser system demonstrates that the spectrometer can give angle-resolved spectra with a large acceptance angle. This will be conductive to revealing the acceleration mechanisms, optimization, and applications of laser-driven proton beams.

  15. Automated segmentation of mouse brain images using extended MRF.

    PubMed

    Bae, Min Hyeok; Pan, Rong; Wu, Teresa; Badea, Alexandra

    2009-07-01

    We introduce an automated segmentation method, extended Markov random field (eMRF), to classify 21 neuroanatomical structures of mouse brain based on three dimensional (3D) magnetic resonance images (MRI). The image data are multispectral: T2-weighted, proton density-weighted, diffusion x, y and z weighted. Earlier research (Ali, A.A., Dale, A.M., Badea, A., Johnson, G.A., 2005. Automated segmentation of neuroanatomical structures in multispectral MR microscopy of the mouse brain. NeuroImage 27 (2), 425-435) successfully explored the use of MRF for mouse brain segmentation. In this research, we study the use of information generated from support vector machine (SVM) to represent the probabilistic information. Since SVM in general has a stronger discriminative power than the Gaussian likelihood method and is able to handle nonlinear classification problems, integrating SVM into MRF improved the classification accuracy. The eMRF employs the posterior probability distribution obtained from SVM to generate a classification based on the MR intensity. Secondly, the eMRF introduces a new potential function based on location information. Third, to maximize the classification performance, the eMRF uses the contribution weights optimally determined for each of the three potential functions: observation, location and contextual functions, which are traditionally equally weighted. We use the voxel overlap percentage and volume difference percentage to evaluate the accuracy of eMRF segmentation and compare the algorithm with three other segmentation methods--mixed ratio sampling SVM (MRS-SVM), atlas-based segmentation and MRF. Validation using classification accuracy indices between automatically segmented and manually traced data shows that eMRF outperforms other methods. PMID:19236923

  16. Density resolution of proton computed tomography

    SciTech Connect

    Schulte, Reinhard W.; Bashkirov, Vladimir; Loss Klock, Margio C.; Li Tianfang; Wroe, Andrew J.; Evseev, Ivan; Williams, David C.; Satogata, Todd

    2005-04-01

    Conformal proton radiation therapy requires accurate prediction of the Bragg peak position. Protons may be more suitable than conventional x rays for this task since the relative electron density distribution can be measured directly with proton computed tomography (CT). However, proton CT has its own limitations, which need to be carefully studied before this technique can be introduced into routine clinical practice. In this work, we have used analytical relationships as well as the Monte Carlo simulation tool GEANT4 to study the principal resolution limits of proton CT. The noise level observed in proton CT images of a cylindrical water phantom with embedded tissue-equivalent density inhomogeneities, which were generated based on GEANT4 simulations, compared well with predictions based on Tschalar's theory of energy loss straggling. The relationship between phantom thickness, initial energy, and the relative electron density resolution was systematically investigated to estimate the proton dose needed to obtain a given density resolution. We show that a reasonable density resolution can be achieved with a relatively small dose, which is comparable to or even lower than that of x-ray CT.

  17. Monte Carlo comparison of x-ray and proton CT for range calculations of proton therapy beams

    NASA Astrophysics Data System (ADS)

    Arbor, N.; Dauvergne, D.; Dedes, G.; Létang, J. M.; Parodi, K.; Quiñones, C. T.; Testa, E.; Rit, S.

    2015-10-01

    Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framework to assess proton CT performances for the main steps of a proton therapy treatment planning, i.e. proton or x-ray CT imaging, conversion to RSP maps based on the calibration of a tissue phantom, and proton dose simulations. Irradiations of a computational phantom with pencil beams were simulated on various anatomical sites and the proton range was assessed on the reference, the proton CT-based and the x-ray CT-based material maps. Errors on the tissue’s RSP reconstructed from proton CT were found to be significantly smaller and less dependent on the tissue distribution. The imaging dose was also found to be much more uniform and conformal to the primary beam. The mean absolute deviation for range calculations based on x-ray CT varies from 0.18 to 2.01 mm depending on the localization, while it is smaller than 0.1 mm for proton CT. Under the assumption of a perfect detection system, proton range predictions based on proton CT are therefore both more accurate and more uniform than those based on x-ray CT.

  18. Proton-counting radiography for proton therapy: a proof of principle using CMOS APS technology

    NASA Astrophysics Data System (ADS)

    Poludniowski, G.; Allinson, N. M.; Anaxagoras, T.; Esposito, M.; Green, S.; Manolopoulos, S.; Nieto-Camero, J.; Parker, D. J.; Price, T.; Evans, P. M.

    2014-06-01

    Despite the early recognition of the potential of proton imaging to assist proton therapy (Cormack 1963 J. Appl. Phys. 34 2722), the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as computed tomography (CT), the water-equivalent-path-length that each proton has travelled through an imaged object must be inferred. Typically, scintillator-based technology has been used in various energy/range telescope designs. Here we propose a very different alternative of using radiation-hard CMOS active pixel sensor technology. The ability of such a sensor to resolve the passage of individual protons in a therapy beam has not been previously shown. Here, such capability is demonstrated using a 36 MeV cyclotron beam (University of Birmingham Cyclotron, Birmingham, UK) and a 200 MeV clinical radiotherapy beam (iThemba LABS, Cape Town, SA). The feasibility of tracking individual protons through multiple CMOS layers is also demonstrated using a two-layer stack of sensors. The chief advantages of this solution are the spatial discrimination of events intrinsic to pixelated sensors, combined with the potential provision of information on both the range and residual energy of a proton. The challenges in developing a practical system are discussed.

  19. Proton-counting radiography for proton therapy: a proof of principle using CMOS APS technology

    PubMed Central

    Poludniowski, G; Allinson, N M; Anaxagoras, T; Esposito, M; Green, S; Manolopoulos, S; Nieto-Camero, J; Parker, D J; Price, T; Evans, P M

    2014-01-01

    Despite the early recognition of the potential of proton imaging to assist proton therapy the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as Computed Tomography (CT), the Water-Equivalent-Path-Length (WEPL) that each proton has travelled through an imaged object must be inferred. Typically, scintillator-based technology has been used in various energy/range telescope designs. Here we propose a very different alternative of using radiation-hard CMOS Active Pixel Sensor (APS) technology. The ability of such a sensor to resolve the passage of individual protons in a therapy beam has not been previously shown. Here, such capability is demonstrated using a 36 MeV cyclotron beam (University of Birmingham Cyclotron, Birmingham, UK) and a 200 MeV clinical radiotherapy beam (iThemba LABS, Cape Town, SA). The feasibility of tracking individual protons through multiple CMOS layers is also demonstrated using a two-layer stack of sensors. The chief advantages of this solution are the spatial discrimination of events intrinsic to pixelated sensors, combined with the potential provision of information on both the range and residual energy of a proton. The challenges in developing a practical system are discussed. PMID:24785680

  20. Development and evaluation of a short-range applicator for treating superficial moving tumors with respiratory-gated spot-scanning proton therapy using real-time image guidance

    NASA Astrophysics Data System (ADS)

    Matsuura, Taeko; Fujii, Yusuke; Takao, Seishin; Yamada, Takahiro; Matsuzaki, Yuka; Miyamoto, Naoki; Takayanagi, Taisuke; Fujitaka, Shinichiro; Shimizu, Shinichi; Shirato, Hiroki; Umegaki, Kikuo

    2016-02-01

    Treatment of superficial tumors that move with respiration (e.g. lung tumors) using spot-scanning proton therapy (SSPT) is a high-priority research area. The recently developed real-time image-gated proton beam therapy (RGPT) system has proven to be useful for treating moving tumors deep inside the liver. However, when treating superficial tumors, the proton’s range is small and so is the sizes of range straggling, making the Bragg-peaks extremely sharp compared to those located in deep-seated tumors. The extreme sharpness of Bragg-peaks is not always beneficial because it necessitates a large number of energy layers to make a spread-out Bragg-peak, resulting in long treatment times, and is vulnerable to motion-induced dose deterioration. We have investigated a method to treat superficial moving tumors in the lung by the development of an applicator compatible with the RGPT system. A mini-ridge filter (MRF) was developed to broaden the pristine Bragg-peak and, accordingly, decrease the number of required energy layers to obtain homogeneous irradiation. The applicator position was designed so that the fiducial marker’s trajectory can be monitored by fluoroscopy during proton beam-delivery. The treatment plans for three lung cancer patients were made using the applicator, and four-dimensional (4D) dose calculations for the RGPT were performed using patient respiratory motion data. The effect of the MRF on the dose distributions and treatment time was evaluated. With the MRF, the number of energy layers was decreased to less than half of that needed without it, whereas the target volume coverage values (D99%, D95%, D50%, D2%) changed by less than 1% of the prescribed dose. Almost no dose distortion was observed after the 4D dose calculation, whereas the treatment time decreased by 26%–37%. Therefore, we conclude that the developed applicator compatible with RGPT is useful to solve the issue in the treatment of superficial moving tumors with SSPT.

  1. A colorimetric proton sponge.

    PubMed

    Swor, Charles D; Zakharov, Lev N; Tyler, David R

    2010-10-15

    1,8-Bis(dimethylamino)naphthalene ("Proton Sponge") and bromomaleic anhydride react quickly at room temperature, generating 3-(4,5-bis(dimethylamino)napthalen-1-yl)furan-2,5-dione (4-maleicanhydridoproton sponge or "MAPS"). MAPS is a deep purple solid that exhibits positive solvatochromism in solution. It is a weaker base than Proton Sponge. When protonated in solution, MAPS loses its color, but the color change can be reversed by deprotonation with a stronger base. MAPS thus acts as a colorimetric version of a proton sponge. PMID:20857948

  2. Imaging.

    PubMed

    Wilkinson, R

    1986-12-01

    Imaging of the musculoskeletal system includes many modalities and is an area that is changing rapidly. Selection of the most accurate techniques and avoidance of duplication are vital to both good patient care and cost containment. PMID:3466135

  3. Evaluation of fatty liver by using in-phase and opposed-phase MR images and in-vivo proton MR spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Seung; Im, In-Chul; Goo, Eun-Hoe; Park, Hyong-Hu; Kwak, Byung-Joon

    2012-12-01

    The purpose of this study was to evaluate the necessity of in-phase and opposed-phase MR images and their correlations with weight, the aspartate aminotransferase/alanine aminotransferase (AST/ALT) value, and age. Magnetic resonance spectroscopy (MRS) was used as a reference in this study. We selected 68 people as subjects, among which 14 were volunteers with normal AST/ALT values ( <40/35 U/L) on a liver function study and 54 were non-alcoholic fatty liver patients for whom ultrasonic images had been obtained within 3 months of the study. In this study, the liver was more enhanced than the spleen or kidney. When the Eq. (3) formula was applied to normal volunteers, the difference between the in-phase and the opposed-phase images was -3.54 12.56. The MRS study result showed a high sensitivity of 96.6% and a specificity of 100% ( p = 0.000) when the cutoff value was 20%. Furthermore, this result showed a high sensitivity of 94% and a specificity of 80% with a similar cutoff when the Eq. (2) formula was applied to non-alcoholic fatty liver patients ( p = 0.000). The MRS study revealed a strong correlation between normal volunteers and non-alcoholic fatty liver patients (r = 0.59, p = 0.04). The correlations between AST/ALT and Eq. (3) (r = 0.45, p = 0.004), age and Eq. (3) (r = 0.73, p = 0.03), and weight and Eq. (3) (r = 0.77, p = 0.000) values were all statistically significant. In the case of non-alcoholic liver disease, MRS was found to be significantly correlated with Eq. (1) (r = 0.39, p = 0.002), Eq. (2) (r = 0.68, p = 0.04), Eq. (3) (r = 0.67, p = 0.04), and AST/ALT (r = 0.77, p = 0.000). In conclusion, in-phase and opposed-phase images can help to distinguish a normal liver from a fatty liver in order to identify non-alcoholic fatty liver patients. The intensity difference between the in-phase and opposed-phase MR signals showed valuable correlations with respect to weight, AST/ALT value, and age, with all values being above the mild lipid value (r = 0.3).

  4. A Single-Scan Imaging Technique for Measurement of the Relative Concentrations of Fat and Water Protons and Their Transverse Relaxation Times

    NASA Astrophysics Data System (ADS)

    Ma, J.; Wehrli, F. W.; Song, H. K.; Hwang, S. N.

    1997-03-01

    A two-component chemical-shift-imaging technique is described from which fat and water images can be obtained in a single scan and in the presence of an inhomogeneous field. In addition, the method provides transverse relaxation ratesR2andR2?separately for each of the spectral components. The method is a combination and extension of the GESFIDE [gradient echo sampling of FID and echo, J. Ma and F. W. Wehrli,J. Magn. Reson. B111,61 (1996)] and the multipoint Dixon techniques. It is based on sampling the descending and ascending portions of a Hahn spin echo with a train of gradient echoes which are spaced at one-half of the chemical-shift modulation period. Processing of the complex echo data, involving an automated phase unwrapping algorithm, affords relative amplitudes and transverse relaxation rates of the two spectral components. An additional benefit of the method is its superior signal-to-noise ratio resulting from echo summation. Applications targeted and illustrated involve MRI osteodensitometry of trabecular bone in the presence of varying fractions of hematopoietic and fatty bone marrow.

  5. Proton microscopy at GSI and FAIR

    SciTech Connect

    Merrill, Frank E; Mariam, Fesseha G; Golubev, A A; Turtikov, V I; Varentsov, D

    2009-01-01

    Proton radiography was invented in the 1990's at Los Alamos National Laboratory (LANL) as a diagnostic to study dynamic material properties under extreme pressures, strain and strain rate. Since this time hundreds of dynamic proton radiography experiments have been performed at LANL and facilities have been commissioned at the Institute for Theoretical and Experimental Physics (ITEP) in Russia for similar applications in dynamic material studies. Recently an international collaboration was formed to develop a new proton radiography capability for the study of dynamic material properties at the Facility for Anti-proton and Ion Research (FAIR) located at Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt, Germany. This new Proton microscope for FAIR (PRIOR) will provide radiographic imaging of dynamic systems with unprecedented spatial, temporal and density resolution, resulting in a window for understanding dynamic material properties at new length scales. These dynamic experiments will be driven with many energy sources including heavy ions, high explosives and lasers. The design of the proton microscope and expected radiographic performance is presented.

  6. In vivo proton range verification: a review

    NASA Astrophysics Data System (ADS)

    Knopf, Antje-Christin; Lomax, Antony

    2013-08-01

    Protons are an interesting modality for radiotherapy because of their well defined range and favourable depth dose characteristics. On the other hand, these same characteristics lead to added uncertainties in their delivery. This is particularly the case at the distal end of proton dose distributions, where the dose gradient can be extremely steep. In practice however, this gradient is rarely used to spare critical normal tissues due to such worries about its exact position in the patient. Reasons for this uncertainty are inaccuracies and non-uniqueness of the calibration from CT Hounsfield units to proton stopping powers, imaging artefacts (e.g. due to metal implants) and anatomical changes of the patient during treatment. In order to improve the precision of proton therapy therefore, it would be extremely desirable to verify proton range in vivo, either prior to, during, or after therapy. In this review, we describe and compare state-of-the art in vivo proton range verification methods currently being proposed, developed or clinically implemented.

  7. A Detector for Proton Computed Tomography

    SciTech Connect

    Blazey, G.; et al.,

    2013-12-06

    Radiation therapy is a widely recognized treatment for cancer. Energetic protons have distinct features that set them apart from photons and make them desirable for cancer therapy as well as medical imaging. The clinical interest in heavy ion therapy is due to the fact that ions deposit almost all of their energy in a sharp peak – the Bragg peak- at the very end of their path. Proton beams can be used to precisely localize a tumor and deliver an exact dose to the tumor with small doses to the surrounding tissue. Proton computed tomography (pCT) provides direct information on the location on the target tumor, and avoids position uncertainty caused by treatment planning based on imaging with X-ray CT. The pCT project goal is to measure and reconstruct the proton relative stopping power distribution directly in situ. To ensure the full advantage of cancer treatment with 200 MeV proton beams, pCT must be realized.

  8. Proton pump inhibitors

    MedlinePLUS

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in the lining ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a condition in ...

  9. The Schwarzschild Proton

    SciTech Connect

    Haramein, Nassim

    2010-11-24

    We review our model of a proton that obeys the Schwarzschild condition. We find that only a very small percentage ({approx}10{sup -39}%) of the vacuum fluctuations available within a proton volume need be cohered and converted to mass-energy in order for the proton to meet the Schwarzschild condition. This proportion is equivalent to that between gravitation and the strong force where gravitation is thought to be {approx}10{sup -38} to 10{sup -40} weaker than the strong force. Gravitational attraction between two contiguous Schwarzschild protons can accommodate both nucleon and quark confinement. We calculate that two contiguous Schwarzschild protons would rotate at c and have a period of 10{sup -23} s and a frequency of 10{sup 22} Hz which is characteristic of the strong force interaction time and a close approximation of the gamma emission typically associated with nuclear decay. We include a scaling law and find that the Schwarzschild proton data point lies near the least squares trend line for organized matter. Using a semi-classical model, we find that a proton charge orbiting at a proton radius at c generates a good approximation to the measured anomalous magnetic moment.

  10. Design and construction of the 1{sup st} proton CT scanner

    SciTech Connect

    Coutrakon, G.; Rykalin, V.; Bashkirov, V.; Hurley, F.; Schulte, R.; Johnson, R.; Sadrozinski, H.

    2013-04-19

    This paper discusses the design and operation of the 1{sup st} proton CT scanner for 3D imaging. Reduction of proton range uncertainties and improved dose accuracy in the patient for treatment planning are central goals. A central CT slice acquired by reconstruction of 134 million proton tracks through a 14 cm spherical polystyrene phantom with high and low density inserts is presented.

  11. Medipix2 as a tool for proton beam characterization

    NASA Astrophysics Data System (ADS)

    Bisogni, M. G.; Cirrone, G. A. P.; Cuttone, G.; Del Guerra, A.; Lojacono, P.; Piliero, M. A.; Romano, F.; Rosso, V.; Sipala, V.; Stefanini, A.

    2009-08-01

    Proton therapy is a technique used to deliver a highly accurate and effective dose for the treatment of a variety of tumor diseases. The possibility to have an instrument able to give online information could reduce the time necessary to characterize the proton beam. To this aim we propose a detection system for online proton beam characterization based on the Medipix2 chip. Medipix2 is a detection system based on a single event counter read-out chip, bump-bonded to silicon pixel detector. The read-out chip is a matrix of 256×256 cells, 55×55 μm 2 each. To demonstrate the capabilities of Medipix2 as a proton detector, we have used a 62 MeV flux proton beam at the CATANA beam line of the LNS-INFN laboratory. The measurements performed confirmed the good imaging performances of the Medipix2 system also for the characterization of proton beams.

  12. Investigation of Proton Focusing and Conversion Efficiency for Proton Fast Ignition

    NASA Astrophysics Data System (ADS)

    Bartal, Teresa Jean

    Recent advances in generating high energy (> 50 MeV) protons from intense laser-matter interactions has opened up new areas of research, with applications in radiography, high energy density physics, and ion-proton beam fast ignition (FI). The ability to focus the proton beam has made these applications more attractive. Fast ignition (FI) is an evolved concept of conventional inertial confinement fusion (ICF). In proton FI, a collimated beam of protons is used to deliver the necessary ignition energy to the compressed Deuterium-Tritium (DT) fuel capsule instead of the original concept of a beam composed of relativistic electrons. In cone-guided FI, a cone is embedded into the side of the fuel capsule where the proton source foil is placed within the cone. The cone provides a clear path to the dense core and protects the proton source foil from radiation during the compression of the capsule. The proton source foil is a segment of a hemispherical shell target used to help focus the proton beam to the core to spark ignition. The viability of proton FI requires focusing of the generated proton beam to a 40 mum spot at the compressed fuel and a laser to proton conversion efficiency of 15%. Here, proton focusing and the laser to proton conversion efficiency are investigated using flat foils and hemispherical shell targets. Experiments were conducted on the 200 TW short pulse laser at Los Alamos Laboratory. The 1053 nm laser pulse delivered 70--80 J on target in 500--600 fs focused by an f/8 parabolic mirror. The generated proton beam from the target was examined by placing a mesh downstream of the target, which the proton beam would pass though and then imaged with a pack of radiochromic film (RCF). A 3D ray-tracing technique was developed to determine the focal position and focal spot size of the generated proton beam by tracing the proton trajectories from the image of the mesh collected by the RCF back through the mesh to the central axis. The focal position calculated from the ray-tracing technique for the flat foils resulted in a real focus, contrasting the convention wisdom of a virtual focus. Investigation of the proton expansion from flat foils established that initially the protons are accelerated normal to the surface, due to the fact that the electrostatic sheath field generated by the escaping hot electrons is only a few microns beyond the rear surface of the foil. As time progresses and more electrons are accelerated into the target by the laser irradiation, the sheath expands away from the rear surface of the foil, developing a bell-shaped curvature. The protons are then accelerated normal to the sheath field, which is at the leading edge of the expansion. Due to the bell-shaped curvature, protons that are accelerated further away from the central axis of the laser interaction experience gradients within the expansion causing the protons to gain radial velocity, which changes the angle of divergence of the protons. The radial velocity gained by the protons affects the trajectory of the protons, resulting in a calculated real focal position when trajectories are calculated the ray-tracing technique. The trajectories of the protons are further affected by the mounting technique. When the foils are mounted to washers for stability, electrons accelerated in the foil escaped into the washer creating a field along the interior wall of washer. The field affects the proton trajectories near the wall and decreases the laser to proton conversion efficiency. With the understanding gained from the flat foil targets, proton focusing is further investigated using freestanding hemispherical shell targets. Using the 3D ray-tracing technique, the calculated focal position is determined to be located inside the radius of curvature of the hemisphere, which is less than the distance of 1.7R (where R is the radius of curvature of the hemispherical shell) determined from proton heating experiments. With the aid of particle-in-cell (PIC) simulations, using the code LSP (large-scale-plasma), it was determined that proton trajecto

  13. Electron-proton spectrometer

    NASA Technical Reports Server (NTRS)

    Winckler, J. R.

    1973-01-01

    An electron-proton spectrometer was designed to measure the geomagnetically trapped radiation in a geostationary orbit at 6.6 earth radii in the outer radiation belt. This instrument is to be flown on the Applications Technology Satellite-F (ATS-F). The electron-proton spectrometer consists of two permanent magnet surface barrier detector arrays and associated electronics capable of selecting and detecting electrons in three energy ranges: (1) 30-50 keV, (2) 150-200 keV, and (3) 500 keV and protons in three energy ranges. The electron-proton spectrometer has the capability of measuring the fluxes of electrons and protons in various directions with respect to the magnetic field lines running through the satellite. One magnet detector array system is implemented to scan between EME north and south through west, sampling the directional flux in 15 steps. The other magnet-detector array system is fixed looking toward EME east.

  14. Proton Engineering Frontier Project

    SciTech Connect

    Choi, Byung-Ho

    2005-06-08

    PEFP (Proton Engineering Frontier Project) approved and launched by the Korean government in July 2002 includes a 100MeV proton linear accelerator development and its utilization and application programs. In the first phase of the project from 2002 to 2005, a 20MeV proton linear accelerator is under development. It consists of 50keV proton injector, 3MeV RFQ, and 20MeV DTL. The 50keV injector had been installed and tested, the 3MeV RFQ is under beam test, and the 20MeV DTL is being fabricated and will be assembled for the beam test in 2005. In parallel, application and utilization programs using proton beam have been planned and developed. Some of them are being carried out. The status and progresses of the project are reported in detail.

  15. Proton Magnetic Resonance Spectroscopic Imaging in Newly Diagnosed Glioblastoma: Predictive Value for the Site of Postradiotherapy Relapse in a Prospective Longitudinal Study

    SciTech Connect

    Laprie, Anne Catalaa, Isabelle; Cassol, Emmanuelle; McKnight, Tracy R.; Berchery, Delphine; Marre, Delphine; Bachaud, Jean-Marc; Berry, Isabelle; Moyal, Elizabeth Cohen-Jonathan

    2008-03-01

    Purpose: To investigate the association between magnetic resonance spectroscopic imaging (MRSI)-defined, metabolically abnormal tumor regions and subsequent sites of relapse in data from patients treated with radiotherapy (RT) in a prospective clinical trial. Methods and Materials: Twenty-three examinations were performed prospectively for 9 patients with newly diagnosed glioblastoma multiforme studied in a Phase I trial combining Tipifarnib and RT. The patients underwent magnetic resonance imaging (MRI) and MRSI before treatment and every 2 months until relapse. The MRSI data were categorized by the choline (Cho)/N-acetyl-aspartate (NAA) ratio (CNR) as a measure of spectroscopic abnormality. CNRs corresponding to T1 and T2 MRI for 1,207 voxels were evaluated before RT and at recurrence. Results: Before treatment, areas of CNR2 (CNR {>=}2) represented 25% of the contrast-enhancing (T1CE) regions and 10% of abnormal T2 regions outside T1CE (HyperT2). The presence of CNR2 was often an early indicator of the site of relapse after therapy. In fact, 75% of the voxels within the T1CE+CNR2 before therapy continued to exhibit CNR2 at relapse, compared with 22% of the voxels within the T1CE with normal CNR (p < 0.05). The location of new contrast enhancement with CNR2 corresponded in 80% of the initial HyperT2+CNR2 vs. 20.7% of the HyperT2 voxels with normal CNR (p < 0.05). Conclusion: Metabolically active regions represented a small percentage of pretreatment MRI abnormalities and were predictive for the site of post-RT relapse. The incorporation of MRSI data in the definition of RT target volumes for selective boosting may be a promising avenue leading to increased local control of glioblastomas.

  16. 200 MeV Proton Radiography Studies with a Hand Phantom Using a Prototype Proton CT Scanner

    PubMed Central

    Plautz, Tia; Bashkirov, V.; Feng, V.; Hurley, F.; Johnson, R.P.; Leary, C.; Macafee, S.; Plumb, A.; Rykalin, V.; Sadrozinski, H.F.-W.; Schubert, K.; Schulte, R.; Schultze, B.; Steinberg, D.; Witt, M.; Zatserklyaniy, A.

    2014-01-01

    Proton radiography has applications in patient alignment and verification procedures for proton beam radiation therapy. In this paper, we report an experiment which used 200 MeV protons to generate proton energy-loss and scattering radiographs of a hand phantom. The experiment used the first-generation proton CT scanner prototype, which was installed on the research beam line of the clinical proton synchrotron at Loma Linda University Medical Center (LLUMC). It was found that while both radiographs displayed anatomical details of the hand phantom, the energy-loss radiograph had a noticeably higher resolution. Nonetheless, scattering radiography may yield more contrast between soft and bone tissue than energy-loss radiography, however, this requires further study. This study contributes to the optimization of the performance of the next-generation of clinical proton CT scanners. Furthermore, it demonstrates the potential of proton imaging (proton radiography and CT), which is now within reach of becoming available as a new, potentially low-dose medical imaging modality. PMID:24710156

  17. Young Investigator Award presentation at the 13th Annual Meeting of the ESMRMB, September 1996, Prague. A proton-electron double-resonance imaging apparatus with simultaneous multiple electron paramagnetic resonance irradiation at 10 mT.

    PubMed

    Alecci, M; Lurie, D J; Nicholson, I; Placidi, G; Sotgiu, A

    1996-01-01

    The detection of free radicals in vivo is very important for the study of many physiologic and pathologic conditions. Free radicals have been implicated in a number of diseases such as ischemia, inflammation, kidney damage, and cancer. Proton-electron double-resonance imaging (PEDRI) allows the indirect detection of free radicals via the Overhauser effect. Nitroxide free radicals used for in vivo PEDRI studies present spectra with two or three lines, but most PEDRI experiments performed to date have used only single-line electron paramagnetic resonance (EPR) irradiation. There is theoretical evidence that simultaneous irradiation of multiple EPR transitions could increase the maximum achievable PEDRI enhancement. From the experimental point of view, this requires the combined use of a suitable multiple-frequency EPR source and a multiple-tuned EPR resonator. A novel radiofrequency (RF) triple-tuned loop-gap resonator for use in PEDRI has recently been developed, and dynamic nuclear polarization (DNP) data were reported. In the present study we describe a new PEDRI apparatus, equipped with a triple-tuned resonator, that is suitable for simultaneous double- or triple-EPR irradiation of nitroxide free radicals. In particular, the details of the EPR hardware used to generate the two or three EPR frequencies are given, and PEDRI images obtained with simultaneous multiple EPR irradiation are shown. Moreover, DNP experimental results showing the increase of the enhancement as a function of the EPR power for single and simultaneous double EPR irradiation are presented. The main goal of this apparatus is to improve the sensitivity and/or to reduce EPR irradiation power in a PEDRI experiment. This is likely to be particularly important in future biologic applications of PEDRI where the applied power must be optimized to reduce sample heating. PMID:9220407

  18. Proton-proton colliding beam facility ISABELLE

    SciTech Connect

    Hahn, H

    1980-01-01

    This paper attempts to present the status of the ISABELLE construction project, which has the objective of building a 400 + 400 GeV proton colliding beam facility. The major technical features of the superconducting accelerators with their projected performance are described. Progress made so far, difficulties encountered, and the program until completion in 1986 is briefly reviewed.

  19. Single-proton spin detection by diamond magnetometry.

    PubMed

    Loretz, M; Rosskopf, T; Boss, J M; Pezzagna, S; Meijer, J; Degen, C L

    2014-10-16

    Extending magnetic resonance imaging to the atomic scale has been a long-standing aspiration, driven by the prospect of directly mapping atomic positions in molecules with three-dimensional spatial resolution. We report detection of individual, isolated proton spins by a nitrogen-vacancy (NV) center in a diamond chip covered by an inorganic salt. The single-proton identity was confirmed by the Zeeman effect and by a quantum coherent rotation of the weakly coupled nuclear spin. Using the hyperfine field of the NV center as an imaging gradient, we determined proton-NV distances of less than 1 nm. PMID:25323696

  20. The Diagnostic Ability of Follow-Up Imaging Biomarkers after Treatment of Glioblastoma in the Temozolomide Era: Implications from Proton MR Spectroscopy and Apparent Diffusion Coefficient Mapping

    PubMed Central

    Bulik, Martin; Kazda, Tomas; Slampa, Pavel; Jancalek, Radim

    2015-01-01

    Objective. To prospectively determine institutional cut-off values of apparent diffusion coefficients (ADCs) and concentration of tissue metabolites measured by MR spectroscopy (MRS) for early differentiation between glioblastoma (GBM) relapse and treatment-related changes after standard treatment. Materials and Methods. Twenty-four GBM patients who received gross total resection and standard adjuvant therapy underwent MRI examination focusing on the enhancing region suspected of tumor recurrence. ADC maps, concentrations of N-acetylaspartate, choline, creatine, lipids, and lactate, and metabolite ratios were determined. Final diagnosis as determined by biopsy or follow-up imaging was correlated to the results of advanced MRI findings. Results. Eighteen (75%) and 6 (25%) patients developed tumor recurrence and pseudoprogression, respectively. Mean time to radiographic progression from the end of chemoradiotherapy was 5.8 ± 5.6 months. Significant differences in ADC and MRS data were observed between those with progression and pseudoprogression. Recurrence was characterized by N-acetylaspartate ≤ 1.5 mM, choline/N-acetylaspartate ≥ 1.4 (sensitivity 100%, specificity 91.7%), N-acetylaspartate/creatine ≤ 0.7, and ADC ≤ 1300 × 10−6 mm2/s (sensitivity 100%, specificity 100%). Conclusion. Institutional validation of cut-off values obtained from advanced MRI methods is warranted not only for diagnosis of GBM recurrence, but also as enrollment criteria in salvage clinical trials and for reporting of outcomes of initial treatment. PMID:26448943

  1. The diffusion tensor imaging (DTI) component of the NIH MRI study of normal brain development (PedsDTI).

    PubMed

    Walker, Lindsay; Chang, Lin-Ching; Nayak, Amritha; Irfanoglu, M Okan; Botteron, Kelly N; McCracken, James; McKinstry, Robert C; Rivkin, Michael J; Wang, Dah-Jyuu; Rumsey, Judith; Pierpaoli, Carlo

    2016-01-01

    The NIH MRI Study of normal brain development sought to characterize typical brain development in a population of infants, toddlers, children and adolescents/young adults, covering the socio-economic and ethnic diversity of the population of the United States. The study began in 1999 with data collection commencing in 2001 and concluding in 2007. The study was designed with the final goal of providing a controlled-access database; open to qualified researchers and clinicians, which could serve as a powerful tool for elucidating typical brain development and identifying deviations associated with brain-based disorders and diseases, and as a resource for developing computational methods and image processing tools. This paper focuses on the DTI component of the NIH MRI study of normal brain development. In this work, we describe the DTI data acquisition protocols, data processing steps, quality assessment procedures, and data included in the database, along with database access requirements. For more details, visit http://www.pediatricmri.nih.gov. This longitudinal DTI dataset includes raw and processed diffusion data from 498 low resolution (3mm) DTI datasets from 274 unique subjects, and 193 high resolution (2.5mm) DTI datasets from 152 unique subjects. Subjects range in age from 10days (from date of birth) through 22years. Additionally, a set of age-specific DTI templates are included. This forms one component of the larger NIH MRI study of normal brain development which also includes T1-, T2-, proton density-weighted, and proton magnetic resonance spectroscopy (MRS) imaging data, and demographic, clinical and behavioral data. PMID:26048622

  2. Reconstruction for proton computed tomography by tracing proton trajectories: a Monte Carlo study.

    PubMed

    Li, Tianfang; Liang, Zhengrong; Singanallur, Jayalakshmi V; Satogata, Todd J; Williams, David C; Schulte, Reinhard W

    2006-03-01

    Proton computed tomography (pCT) has been explored in the past decades because of its unique imaging characteristics, low radiation dose, and its possible use for treatment planning and on-line target localization in proton therapy. However, reconstruction of pCT images is challenging because the proton path within the object to be imaged is statistically affected by multiple Coulomb scattering. In this paper, we employ GEANT4-based Monte Carlo simulations of the two-dimensional pCT reconstruction of an elliptical phantom to investigate the possible use of the algebraic reconstruction technique (ART) with three different path-estimation methods for pCT reconstruction. The first method assumes a straight-line path (SLP) connecting the proton entry and exit positions, the second method adapts the most-likely path (MLP) theoretically determined for a uniform medium, and the third method employs a cubic spline path (CSP). The ART reconstructions showed progressive improvement of spatial resolution when going from the SLP [2 line pairs (lp) cm(-1)] to the curved CSP and MLP path estimates (5 lp cm(-1)). The MLP-based ART algorithm had the fastest convergence and smallest residual error of all three estimates. This work demonstrates the advantage of tracking curved proton paths in conjunction with the ART algorithm and curved path estimates. PMID:16878573

  3. A maximum likelihood proton path formalism for application in proton computed tomography.

    PubMed

    Schulte, R W; Penfold, S N; Tafas, J T; Schubert, K E

    2008-11-01

    The limited spatial resolution in proton computed tomography (pCT) in comparison to x-ray CT is related to multiple Coulomb scattering (MCS) within the imaged object. The current generation pCT design utilizes silicon detectors that measure the position and direction of individual protons prior to and post-traversing the patient to maximize the knowledge of the path of the proton within the imaged object. For efficient reconstruction with the proposed pCT system, one needs to develop compact and flexible mathematical formalisms that model the effects of MCS as the proton traverses the imaged object. In this article, a compact, matrix-based most likely path (MLP) formalism is presented employing Bayesian statistics and a Gaussian approximation of MCS. Using GEANT4 simulations in a homogeneous 20 cm water cube, the MLP expression was found to be able to predict the Monte Carlo tracks of 200 MeV protons to within 0.6 mm on average when employing 3sigma cuts on the relative exit angle and exit energy. These cuts were found to eliminate the majority of events not conforming to the Gaussian model of MCS used in the MLP derivation. M riszwana Banu PMID:19070218

  4. Reconstruction for proton computed tomography by tracing proton trajectories: A Monte Carlo study

    SciTech Connect

    Li Tianfang; Liang Zhengrong; Singanallur, Jayalakshmi V.; Satogata, Todd J.; Williams, David C.; Schulte, Reinhard W.

    2006-03-15

    Proton computed tomography (pCT) has been explored in the past decades because of its unique imaging characteristics, low radiation dose, and its possible use for treatment planning and on-line target localization in proton therapy. However, reconstruction of pCT images is challenging because the proton path within the object to be imaged is statistically affected by multiple Coulomb scattering. In this paper, we employ GEANT4-based Monte Carlo simulations of the two-dimensional pCT reconstruction of an elliptical phantom to investigate the possible use of the algebraic reconstruction technique (ART) with three different path-estimation methods for pCT reconstruction. The first method assumes a straight-line path (SLP) connecting the proton entry and exit positions, the second method adapts the most-likely path (MLP) theoretically determined for a uniform medium, and the third method employs a cubic spline path (CSP). The ART reconstructions showed progressive improvement of spatial resolution when going from the SLP [2 line pairs (lp) cm{sup -1}] to the curved CSP and MLP path estimates (5 lp cm{sup -1}). The MLP-based ART algorithm had the fastest convergence and smallest residual error of all three estimates. This work demonstrates the advantage of tracking curved proton paths in conjunction with the ART algorithm and curved path estimates.

  5. Are protons nonidentical fermions?

    SciTech Connect

    Mart, T.

    2014-09-25

    We briefly review the progress of our investigation on the electric (charge) radius of the proton. In order to explain the recently measured proton radius, which is significantly smaller than the standard CODATA value, we assume that the real protons radii are not identical, they are randomly distributed in a certain range. To obtain the measured radius we average the radii and fit both the mean radius and the range. By using an averaged dipole form factor we obtain the charge radius r{sub E} = 0.8333 fm, in accordance with the recent measurement of the Lamb shift in muonic hydrogen.

  6. Proof of principle study of the use of a CMOS active pixel sensor for proton radiography

    SciTech Connect

    Seco, Joao; Depauw, Nicolas

    2011-02-15

    Purpose: Proof of principle study of the use of a CMOS active pixel sensor (APS) in producing proton radiographic images using the proton beam at the Massachusetts General Hospital (MGH). Methods: A CMOS APS, previously tested for use in s-ray radiation therapy applications, was used for proton beam radiographic imaging at the MGH. Two different setups were used as a proof of principle that CMOS can be used as proton imaging device: (i) a pen with two metal screws to assess spatial resolution of the CMOS and (ii) a phantom with lung tissue, bone tissue, and water to assess tissue contrast of the CMOS. The sensor was then traversed by a double scattered monoenergetic proton beam at 117 MeV, and the energy deposition inside the detector was recorded to assess its energy response. Conventional x-ray images with similar setup at voltages of 70 kVp and proton images using commercial Gafchromic EBT 2 and Kodak X-Omat V films were also taken for comparison purposes. Results: Images were successfully acquired and compared to x-ray kVp and proton EBT2/X-Omat film images. The spatial resolution of the CMOS detector image is subjectively comparable to the EBT2 and Kodak X-Omat V film images obtained at the same object-detector distance. X-rays have apparent higher spatial resolution than the CMOS. However, further studies with different commercial films using proton beam irradiation demonstrate that the distance of the detector to the object is important to the amount of proton scatter contributing to the proton image. Proton images obtained with films at different distances from the source indicate that proton scatter significantly affects the CMOS image quality. Conclusion: Proton radiographic images were successfully acquired at MGH using a CMOS active pixel sensor detector. The CMOS demonstrated spatial resolution subjectively comparable to films at the same object-detector distance. Further work will be done in order to establish the spatial and energy resolution of the CMOS detector for protons. The development and use of CMOS in proton radiography could allow in vivo proton range checks, patient setup QA, and real-time tumor tracking.

  7. Elemental bioimaging of thulium in mouse tissues by laser ablation-ICPMS as a complementary method to heteronuclear proton magnetic resonance imaging for cell tracking experiments.

    PubMed

    Reifschneider, Olga; Wentker, Kristina S; Strobel, Klaus; Schmidt, Rebecca; Masthoff, Max; Sperling, Michael; Faber, Cornelius; Karst, Uwe

    2015-04-21

    Due to the fact that cellular therapies are increasingly finding application in clinical trials and promise success by treatment of fatal diseases, monitoring strategies to investigate the delivery of the therapeutic cells to the target organs are getting more and more into the focus of modern in vivo imaging methods. In order to monitor the distribution of the respective cells, they can be labeled with lanthanide complexes such as thulium-1,4,7,10-tetraazacyclodoecane-?,?,?,?-tetramethyl-1,4,7,10-tetraacetic acid (Tm(DOTMA)). In this study, experiments on a mouse model with two different cell types, namely, tumor cells and macrophages labeled with Tm(DOTMA), were performed. The systemic distribution of Tm(DOTMA) of both cell types was investigated by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS). Using the high resolution of 25 ?m, distribution maps of Tm in different tissues such as tumor, liver, lung, and spleen as well as in explanted gel pellets were generated and the behavior of the labeled cells inside the tissue was investigated. Additionally, quantitative data were obtained using homemade matrix-matched standards based on egg yolk. Using this approach, limits of detection and quantification of 2.2 and 7.4 ngg(-1), respectively, and an excellent linearity over the concentration range from 0.01 to 46 ?gg(-1) was achieved. The highest concentration of the label agent, 32.4 ?gg(-1), in tumor tissue was observed in the area of the injection of the labeled tumor cells. Regarding the second experiment with macrophages for cell tracking, Tm was detected in the explanted biogell pellet with relatively low concentrations below 60 ngg(-1) and in the liver with a relatively high concentration of 10 ?gg(-1). Besides thulium, aluminum was detected with equal distribution behavior in the tumor section due to a contamination resulting from the labeling procedure, which includes the usage of an Al electrode. PMID:25791208

  8. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. )

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  9. Proton channel models

    PubMed Central

    Pupo, Amaury; Baez-Nieto, David; Martnez, Agustn; Latorre, Ramn; Gonzlez, Carlos

    2014-01-01

    Voltage-gated proton channels are integral membrane proteins with the capacity to permeate elementary particles in a voltage and pH dependent manner. These proteins have been found in several species and are involved in various physiological processes. Although their primary topology is known, lack of details regarding their structures in the open conformation has limited analyses toward a deeper understanding of the molecular determinants of their function and regulation. Consequently, the function-structure relationships have been inferred based on homology models. In the present work, we review the existing proton channel models, their assumptions, predictions and the experimental facts that support them. Modeling proton channels is not a trivial task due to the lack of a close homolog template. Hence, there are important differences between published models. This work attempts to critically review existing proton channel models toward the aim of contributing to a better understanding of the structural features of these proteins. PMID:24755912

  10. Proton beam therapy facility

    SciTech Connect

    Not Available

    1984-10-09

    It is proposed to build a regional outpatient medical clinic at the Fermi National Accelerator Laboratory (Fermilab), Batavia, Illinois, to exploit the unique therapeutic characteristics of high energy proton beams. The Fermilab location for a proton therapy facility (PTF) is being chosen for reasons ranging from lower total construction and operating costs and the availability of sophisticated technical support to a location with good access to patients from the Chicago area and from the entire nation. 9 refs., 4 figs., 26 tabs.

  11. Proton irradiation on materials

    NASA Astrophysics Data System (ADS)

    Chang, C. Ken

    1993-12-01

    A computer code is developed by utilizing a radiation transport code developed at NASA Langley Research Center to study the proton radiation effects on materials which have potential application in NASA's future space missions. The code covers the proton energy from 0.01 Mev to 100 Gev and is sufficient for energetic protons encountered in both low earth and geosynchronous orbits. With some modification, the code can be extended for particles heavier than proton as the radiation source. The code is capable of calculating the range, stopping power, exit energy, energy deposition coefficients, dose, and cumulative dose along the path of the proton in a target material. The target material can be any combination of the elements with atomic number ranging from 1 to 92, or any compound with known chemical composition. The generated cross section for a material is stored and is reused in future to save computer time. This information can be utilized to calculate the proton dose a material would receive in an orbit when the radiation environment is known. It can also be used to determine, in the laboratory, the parameters such as beam current of proton and irradiation time to attain the desired dosage for accelerated ground testing of any material. It is hoped that the present work be extended to include polymeric and composite materials which are prime candidates for use as coating, electronic components, and structure building. It is also desirable to determine, for ground testing these materials, the laboratory parameters in order to simulate the dose they would receive in space environments. A sample print-out for water subject to 1.5 Mev proton is included as a reference.

  12. Proton irradiation on materials

    NASA Technical Reports Server (NTRS)

    Chang, C. Ken

    1993-01-01

    A computer code is developed by utilizing a radiation transport code developed at NASA Langley Research Center to study the proton radiation effects on materials which have potential application in NASA's future space missions. The code covers the proton energy from 0.01 Mev to 100 Gev and is sufficient for energetic protons encountered in both low earth and geosynchronous orbits. With some modification, the code can be extended for particles heavier than proton as the radiation source. The code is capable of calculating the range, stopping power, exit energy, energy deposition coefficients, dose, and cumulative dose along the path of the proton in a target material. The target material can be any combination of the elements with atomic number ranging from 1 to 92, or any compound with known chemical composition. The generated cross section for a material is stored and is reused in future to save computer time. This information can be utilized to calculate the proton dose a material would receive in an orbit when the radiation environment is known. It can also be used to determine, in the laboratory, the parameters such as beam current of proton and irradiation time to attain the desired dosage for accelerated ground testing of any material. It is hoped that the present work be extended to include polymeric and composite materials which are prime candidates for use as coating, electronic components, and structure building. It is also desirable to determine, for ground testing these materials, the laboratory parameters in order to simulate the dose they would receive in space environments. A sample print-out for water subject to 1.5 Mev proton is included as a reference.

  13. The Effect of Flip Angle on the Accuracy and Repeatability of Hepatic Proton Density Fat Fraction Estimation by Complex data-based, T1-independent, T2*-corrected, Spectrum-Modeled Magnetic Resonance Imaging

    PubMed Central

    Johnson, Benjamin L.; Schroeder, Michael E.; Wolfson, Tanya; Gamst, Anthony C.; Hamilton, Gavin; Shiehmorteza, Masoud; Loomba, Rohit; Schwimmer, Jeffrey B.; Reeder, Scott; Middleton, Michael S.; Sirlin, Claude B.

    2013-01-01

    Purpose To evaluate the effect of flip angle (FA) on accuracy and within-examination repeatability of hepatic proton-density fat fraction (PDFF) estimation with complex data-based magnetic resonance imaging (MRI). Materials and Methods PDFF was estimated at 3T in thirty subjects, using two sets of five MRI sequences with FA from 1 to 5 in each set. One set used 7ms repetition time and acquired 6 echoes (TR7/E6); the other used 14ms and acquired 12 echoes (TR14/E12). For each FA in both sets, the accuracy of MRI-PDFF was assessed relative to MR spectroscopy (MRS)-PDFF using four regression parameters (slope, intercept, average bias, R2). Each subject had four random sequences repeated; within-examination repeatability of MRI-PDFF for each FA was assessed with intraclass correlation coefficient (ICC). Pairwise comparisons were made using bootstrap-based tests. Results Most FAs provided high MRI-PDFF estimation accuracy (intercept range -1.250.84, slope 0.891.06, average bias 0.241.65, R2 0.850.97). Most comparisons of regression parameters between FAs were not significant. Informally, in the TR7/E6 set, FAs of 2 and 3 provided the highest accuracy, while FAs of 1 and 5 provided the lowest. In the TR14/E12 set, accuracy parameters did not differ consistently between FAs. FAs in both sets provided high within-examination repeatability (ICC range 0.9810.998). Conclusion MRI-PDFF was repeatable and, for most FAs, accurate in both sequence sets. In the TR7/E6 sequence set, FAs of 2 and 3 informally provided the highest accuracy. In the TR14/E12 sequence set, all FAs provided similar accuracy. PMID:23596052

  14. Statistical Behavior of Proton and Electron Auroras During Substorms

    NASA Astrophysics Data System (ADS)

    Morsony, B.; Mende, S.; Frey, H.; Immel, T.

    2002-12-01

    The IMAGE FUV imager can provide global maps of electron and proton precipitation and it is possible to observe how these maps change as a result of substorms. The large body of IMAGE FUV data permits the performance of a superimposed epoch analysis for many substorms. For each substorm the onset locations and times were determined from the Wideband Imaging Camera (WIC) images which represent mainly electron auroras. For the superimposed epoch analysis the WIC (electron) and Spectrographic Imager SI12 (proton) images were transformed into rectangular magnetic latitude (MLAT) and magnetic local time coordinates (MLT). Each event was plotted on a time scale related to the time of onset and the MLT scale was shifted until the onset point of each substorm was lined up at 0 relative magnetic local time (RMLT). A double Gaussian was then fitted to the data at RMLT of -4,-2,0,+2,+4 by representing the auroral intensity, I, as a function of MLAT. From the Gaussian coefficients we were able to obtain the mean of the peak auroral intensities, the mean location of the maximum intensity, and the mean position of the poleward and equatorward boundary of the proton and electron precipitation. From 91 substorms we derived some statistically meaningful quantities. We showed that pre-substorm there is an equatorward motion of the equatorward boundary of the electron and proton aurora. At onset the proton auroral peak intensity increases only by a factor of two compared to a factor of 5 for the electrons. There is rapid poleward expansion of the proton aurora after onset which slows down after the first few minutes. The electron onset continues towards higher latitudes. The relative position of the proton and electron aurora and their boundaries was investigated for various RMLT during substorm phases.

  15. Laser-plasma interaction generated proton isochoric heating and focusing

    NASA Astrophysics Data System (ADS)

    Zhang, Bingbing

    Fast ignition (FI) by laser-generated, ballistically focused protons is a new proposed alternative to the original concept of FI by laser-generated relativistic electrons. The key potential advantage in using proton FI lies in less-complex energy transport into dense plasma. Because of the high mass ratio of proton over electron, protons can maintain a stiff trace while traversing dense plasma. The requirement for proton FI is to heat D-T fuel with total 18 k3 proton energy at 3 MeV in 10 ps over 30 mum diameter. Due to the generation mechanism, a concave spherical target surface is used to focus protons. The focal plane position and focal size are currently under study. In this dissertation, for the first time, the blackbody radiation from the proton-heated target is used for the temperature measurement. Through the temperature measurement, focal plane position can be derived to be the location where the target's rear surface temperature peaks. In the experiments, the heated target's rear surface is reflected and imaged onto a detector using a spherically-bent multilayer mirror operating at near-normal incidence angle and a flat 45 turning mirror. Two sets of multilayer mirrors are precisely fabricated to reflect photons with energy of 68 eV and 256 eV. The XUV images of Al and polymer slabs at different separations from hemisphere are captured and analyzed to display the results of focal plane position for protons with different energy. Another novel technique for detecting both focal size and focal plane position of protons with different energy is proposed in this dissertation. In this technique, radiochromic films (RCF) are used to picture Cu mesh images projected by focused protons. The RCF consists of a series of films which stops different energy protons. By studying the magnifications and using the proportionalities of similar triangles, proton beam's focal plane position and focal size can be determined. The focal plane position calculated through this method is compared with the value derived from XUV images under the same condition in this dissertation.

  16. Feasibility study of proton-based quality assurance of proton range compensator

    NASA Astrophysics Data System (ADS)

    Park, S.; Jeong, C.; Min, B. J.; Kwak, J.; Lee, J.; Cho, S.; Shin, D.; Lim, Y. K.; Park, S. Y.; Lee, S. B.

    2013-06-01

    All patient specific range compensators (RCs) are customized for achieving distal dose conformity of target volume in passively scattered proton therapy. Compensators are milled precisely using a computerized machine. In proton therapy, precision of the compensator is critical and quality assurance (QA) is required to protect normal tissues and organs from radiation damage. This study aims to evaluate the precision of proton-based quality assurance of range compensator. First, the geometry information of two compensators was extracted from the DICOM Radiotherapy (RT) plan. Next, RCs were irradiated on the EBT film individually by proton beam which is modulated to have a photon-like percent depth dose (PDD). Step phantoms were also irradiated on the EBT film to generate calibration curve which indicates relationship between optical density of irradiated film and perpendicular depth of compensator. Comparisons were made using the mean absolute difference (MAD) between coordinate information from DICOM RT and converted depth information from the EBT film. MAD over the whole region was 1.7, and 2.0 mm. However, MAD over the relatively flat regions on each compensator selected for comparison was within 1 mm. These results shows that proton-based quality assurance of range compensator is feasible and it is expected to achieve MAD over the whole region less than 1 mm with further correction about scattering effect of proton imaging.

  17. Feasibility of pulsed proton acoustics for 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Alsanea, Fahed M.

    Proton therapy has the potential to deposit its energy in tissue with high conformity to the tumor and significantly reduced integral dose to normal tissue compared to conventional radiation, such as x-rays. As a result, local control can be enhanced while reducing side-effects and secondary cancers. This is due to the way charged Particles deposit their energy or dose, where protons form a Bragg peak and establish a well-defined distal edge as a function of depth (range). To date, the dose delivered to a patient from proton therapy remains uncertain, in particular the positioning of the distal edge of the Bragg peak and the lateral displacement of the beam. The need for quality assurance methods to monitor the delivered dose during proton therapy, in particular intensity modulated proton therapy (IMPT) is critical. We propose to measure the acoustic signal generated from the deposited energy from ionizing radiation, in particular a proton beam; and to investigate the feasibility of ultrasound tomographic imaging to map the three dimensional dose (3D) dose from a proton pencil beam. A pulsed proton beam in water was simulated using Monte Carlo (MC) methods, and the pressure signal resulting from the deposited dose was simulated based on the thermoacoustics wave. A cylindrical scanner design with 71 ultrasound transducers focused to a centeral point within the scanner was utilized. Finally, a 3-D filtered backprojection algorithm was developed to reconstruct computed tomographic images of the deposited dose. The MC dose profile was compared to the radioacoustic reconstructed images, and the dependency of the proton pulse sequence parameters, pulse width (tPW) and rise time ( Delta t), on sensitivity were investigated. Based on simulated data, the reconstructed radioacoustic image intensity was within 2%, on average, of the MC generated dose within the Bragg peak, and the location of the distal edge was within 0.5mm. The simulated pressure signal for different tPW and Delta t for the same number of protons (1.8x107) demonstrated that compressing the protons in a shorter period of time significantly increased the thermoacoustic signal and thus sensitivity. This study demonstrates that computed tomographic scanner based on ionizing radiation induced acoustics can be used to verify dose distribution and proton range. Realizing this technology into the clinic will have significant impact on treatment verification during particle beam therapy and image guided techniques.

  18. Proton Radiography Peers into Metal Solidification

    NASA Astrophysics Data System (ADS)

    Clarke, Amy; Imhoff, Seth; Gibbs, Paul; Cooley, Jason; Morris, Christopher; Merrill, Frank; Hollander, Brian; Mariam, Fesseha; Ott, Thomas; Barker, Martha; Tucker, Tim; Lee, Wah-Keat; Fezzaa, Kamel; Deriy, Alex; Patterson, Brian; Clarke, Kester; Montalvo, Joel; Field, Robert; Thoma, Dan; Smith, James; Teter, David

    2013-06-01

    Historically, metals are cut up and polished to see the structure and to infer how processing influences the evolution. We can now peer into a metal during processing without destroying it using proton radiography. Understanding the link between processing and structure is important because structure profoundly affects the properties of engineering materials. Synchrotron x-ray radiography has enabled real-time glimpses into metal solidification. However, x-ray energies favor the examination of small volumes and low density metals. Here we use high energy proton radiography for the first time to image a large metal volume (>10,000 mm3) during melting and solidification. We also show complementary x-ray results from a small volume (<1 mm3), bridging four orders of magnitude. Real-time imaging will enable efficient process development and the control of structure evolution to make materials with intended properties; it will also permit the development of experimentally informed, predictive structure and process models.

  19. Proton re-evaluated

    NASA Astrophysics Data System (ADS)

    Clark, P. S.

    1986-08-01

    The three versions of the Proton booster used to date are presented and connections are made between the Proton and the U.S.S.R.'s lunar program. The question as to whether or not the proton could be manrated is addressed. The original version of the Proton, known as the SL-9 vehicle, consists of the first stage cluster of six engines with a 13-ton second stage. The second version was the SL-12 and the third version was the SL-13. The SL-13 consists of the SL-9 with a new 5.6-ton third stage added. The SL-12, introduced before the SL-13, uses the basic three stages of the SL-13 with a fourth escape stage added. The use of the SL-12 vehicle in two major series of applications satellites put in earth orbit is described. It is noted that if the loss of the Challenger Orbiter results in a major shift in Shuttle payload philosophy, the Proton and other expendable boosters will be called upon to fill the gaps.

  20. Proton dynamics in cancer

    PubMed Central

    2010-01-01

    Cancer remains a leading cause of death in the world today. Despite decades of research to identify novel therapeutic approaches, durable regressions of metastatic disease are still scanty and survival benefits often negligible. While the current strategy is mostly converging on target-therapies aimed at selectively affecting altered molecular pathways in tumor cells, evidences are in parallel pointing to cell metabolism as a potential Achilles' heel of cancer, to be disrupted for achieving therapeutic benefit. Critical differences in the metabolism of tumor versus normal cells, which include abnormal glycolysis, high lactic acid production, protons accumulation and reversed intra-extracellular pH gradients, make tumor site a hostile microenvironment where only cancer cells can proliferate and survive. Inhibiting these pathways by blocking proton pumps and transporters may deprive cancer cells of a key mechanism of detoxification and thus represent a novel strategy for a pleiotropic and multifaceted suppression of cancer cell growth. Research groups scattered all over the world have recently started to investigate various aspects of proton dynamics in cancer cells with quite encouraging preliminary results. The intent of unifying investigators involved in this research line led to the formation of the "International Society for Proton Dynamics in Cancer" (ISPDC) in January 2010. This is the manifesto of the newly formed society where both basic and clinical investigators are called to foster translational research and stimulate interdisciplinary collaboration for the development of more specific and less toxic therapeutic strategies based on proton dynamics in tumor cell biology. PMID:20550689

  1. High Temperature Protonic Conductors

    NASA Technical Reports Server (NTRS)

    Dynys, Fred; Berger, Marie-Helen; Sayir, Ali

    2007-01-01

    High Temperature Protonic Conductors (HTPC) with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells. Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated. A laser melt modulation (LMM) process was utilized to fabricate bulk samples, while pulsed laser deposition (PLD) was utilized to fabricate thin film membranes . Sr3Ca(1+x)Nb(2-x)O9 and SrCe(1-x)Y(x)O3 bulk samples were fabricated by LMM. Thin film BaCe(0.85)Y(0.15)O3 membranes were fabricated by PLD on porous substrates. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.

  2. Giant resonances - why protons

    SciTech Connect

    Bertrand, F.E.

    1983-01-01

    Protons excite giant resonances, indeed the systematic establishment of the existence of the first non-dipole giant resonance, the giant quadrupole resonance (GQR) came from the use of inelastic proton scatering. The question addressed, however, is how does the proton stack up for such studies when compared to the use of other hadronic probes. What can we uniquely learn about giant multipole resonances using proton scattering. Specifically, results from (p, p'), and (..cap alpha.., ..cap alpha..') and (/sup 16/o, /sup 16/O') reactions are compared as regards excitation of giant multipole resonances, and some of the advantages and disadvantages to the use of each probe are detailed. It is hoped to leave the impression that it is in the determination of resonance multipolarity by comparison of measured and calculated angular distributions that the proton is a winner. It is shown what we are learning about high-L (L > 3) giant resonances using the (p, p') angular distribution. This discussion will generally be limited to isoscalar electric (i.e., T = 0, S = 0) giant resonances.

  3. Proton charge extensions

    NASA Astrophysics Data System (ADS)

    Stryker, Jesse R.; Miller, Gerald A.

    2016-01-01

    We examine how corrections to S -state energy levels En S in hydrogenic atoms due to the finite proton size are affected by moments of the proton charge distribution. The corrections to En S are computed moment by moment. The results demonstrate that the next-to-leading order term in the expansion is of order rp/aB times the size of the leading order term. Our analysis thus dispels any concern that the larger relative size of this term for muonic hydrogen versus electronic hydrogen might account for the current discrepancy of proton radius measurements extracted from the two systems. Furthermore, the next-to-leading order term in powers of rp/aB that we derive from a dipole proton form factor is proportional to , rather than , as would be expected from the scalar nature of the form factor. The dependence of the finite-size correction on and higher odd-power moments is shown to be a general result for any spherically symmetric proton charge distribution. A method for computing the moment expansion of the finite-size correction to arbitrary order is introduced and the results are tabulated for principal quantum numbers up to n =7 .

  4. Magnifying lens for 800 MeV proton radiography

    SciTech Connect

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-10-15

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

  5. Magnifying lens for 800 MeV proton radiography

    NASA Astrophysics Data System (ADS)

    Merrill, F. E.; Campos, E.; Espinoza, C.; Hogan, G.; Hollander, B.; Lopez, J.; Mariam, F. G.; Morley, D.; Morris, C. L.; Murray, M.; Saunders, A.; Schwartz, C.; Thompson, T. N.

    2011-10-01

    This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.

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

    SciTech Connect

    Wonneberger, Uta; Schnackenburg, Bernhard; Streitparth, Florian Walter, Thula Rump, Jens Teichgraeber, Ulf K. M.

    2010-04-15

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

  7. Solar proton event forecasts

    NASA Astrophysics Data System (ADS)

    Heckman, G. R.

    1988-04-01

    The United States operates a space weather service to provide information on space hazards including solar proton events to Federal government agencies and other users who operate systems that are affected by disturbances in the upper atmosphere and interplanetary environment. The observation and prediction of solar proton events has been continuous through solar cycle 21 (1976 to 1986), establishing a base of experience that can be used in providing similar support to space operations in the 1990's. The observations, indices, alerts, and forecasts used in the service are described. Also provided is a short summary of the experience obtained from making proton event predictions in solar cycle 21 including the years 1976 to 1986.

  8. The physics of proton therapy

    NASA Astrophysics Data System (ADS)

    Newhauser, Wayne D.; Zhang, Rui

    2015-04-01

    The physics of proton therapy has advanced considerably since it was proposed in 1946. Today analytical equations and numerical simulation methods are available to predict and characterize many aspects of proton therapy. This article reviews the basic aspects of the physics of proton therapy, including proton interaction mechanisms, proton transport calculations, the determination of dose from therapeutic and stray radiations, and shielding design. The article discusses underlying processes as well as selected practical experimental and theoretical methods. We conclude by briefly speculating on possible future areas of research of relevance to the physics of proton therapy.

  9. Using Proton Radioactivity to Locate the Proton Dripline

    NASA Astrophysics Data System (ADS)

    Davids, C. N.; Seweryniak, D. S.

    2003-04-01

    Experiments in proton radioactivity yield the proton decay energy E_p, which in turn gives the proton separation energy S_p. By definition, Sp is negative for nuclides beyond the proton drip line. Except for Z=59 and Z=61, proton emitters have been observed for every odd-Z element in the region Z=51-83. In addition, information from alpha-decay branches of proton emitters allows the derivation of Sp values for the alpha-decay daughter nuclei, providing further information on the mass surface near the proton drip line. The location of the proton dripline for this region will be shown, and compared with the results of various mass predictions.

  10. Proton irradiation and endometriosis

    SciTech Connect

    Wood, D.H.; Yochmowitz, M.G.; Salmon, Y.L.; Eason, R.L.; Boster, R.A.

    1983-08-01

    It was found that female rhesus monkeys given single total-body exposures of protons of varying energies developed endometriosis at a frequency significantly higher than that of nonirradiated animals of the same age. The minimum latency period was determined to be 7 years after the proton exposure. The doses and energies of the radiation received by the experimental animals were within the range that could be received by an aircrew member in near-earth orbit during a random solar flare event. It is concluded that endometriosis should be a consideration in assessing the risk of delayed radiation effects in female crew members. 15 references.

  11. Automated method of tracing proton tracks in nuclear emulsions

    NASA Astrophysics Data System (ADS)

    Ruan, Jin-lu; Li, Hong-yun; Song, Ji-wen; Zhang, Jian-fu; Chen, Liang; Zhang, Zhong-bing; Liu, Jin-liang; Liu, Lin-yue

    2015-07-01

    The low performance of the manual recognition of proton-recoil tracks in nuclear emulsions has limited its application to energy spectrum measurement of a pulsed neutron source. We developed an automated microscope system to trace proton-recoil tracks in nuclear emulsions. Given a start point on the proton track of interest, the microscope system can automatically trace and record the entire track using an image processing algorithm. Tests indicate that no interaction of the operator is needed in tracing the entire track. This automated microscope greatly reduces the labor of the operator and increases the efficiency of track data collection in nuclear emulsion.

  12. Proton-Proton Scattering at 105 Mev and 75 Mev

    DOE R&D Accomplishments Database

    Birge, R. W.; Kruse, U. E.; Ramsey, N. F.

    1951-01-31

    The scattering of protons by protons provides an important method for studying the nature of nuclear forces. Recent proton-proton scattering experiments at energies as high as thirty Mev{sup 1} have failed to show any appreciable contribution to the cross section from higher angular momentum states, but it is necessary to bring in tensor forces to explain the magnitude of the observed cross section.

  13. High-energy test of proton radiography concepts

    SciTech Connect

    Amann, J.F.; Atencio, L.G.; Espinoza, C.J.

    1997-07-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this work was to demonstrate the use of high energy protons to produce radiographs of heavy metal test objects. The authors executed a proof-of-principle experiment using GeV proton beams available at the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS). The experiment produced proton radiographs of a suitably dense, unclassified test object. The experiment tested capabilities in data collection, image reconstruction, and hydro-code simulation and validated models of high-energy proton radiography. A lens was designed using existing quadrupole magnets, constructed on the A1 beam line of the AGS and used to image 10-GeV protons. The results include: (1) images made with an integrating detector, (2) measurements of the background and measurements of the resolution functions, and (3) forward model fits to the transmission data. In all cases the results agree with initial estimates and provide strong support for the utility of proton radiography as a new hydrotest diagnostic.

  14. Predictions of diffractive cross sections in proton-proton collisions

    SciTech Connect

    Goulianos, Konstantin

    2013-04-15

    We review our pre-LHC predictions of the total, elastic, total-inelastic, and diffractive components of proton-proton cross sections at high energies, expressed in the form of unitarized expressions based on a special parton-model approach to diffraction employing inclusive proton parton distribution functions and QCD color factors and compare with recent LHC results.

  15. Three new defined proton affinities for polybasic molecules in the gas-phase: Proton microaffinity, proton macroaffinity and proton overallaffinity

    NASA Astrophysics Data System (ADS)

    Salehzadeh, Sadegh; Bayat, Mehdi

    2006-08-01

    A theoretical study on complete protonation of a series of tetrabasic molecules with general formula N[(CH 2) nNH 2][(CH 2) mNH 2][(CH 2) pNH 2] (tren, pee, ppe, tpt, epb and ppb) is reported. For first time, three kinds of gas-phase proton affinities for each polybasic molecule are defined as: 'proton microaffinity (PA n, i)', 'proton macroaffinity (PA)' and 'proton overall affinity ( PA)'. The variations of calculated logPA in the series of these molecules is very similar to that of their measured log Kn. There is also a good correlation between the calculated gas-phase proton macroaffinities and proton overallaffinities with corresponding equilibrium macroconstants and overall protonation constants in solution.

  16. The Search for Proton Decay.

    ERIC Educational Resources Information Center

    Marshak, Marvin L.

    1984-01-01

    Provides the rationale for and examples of experiments designed to test the stability of protons and bound neutrons. Also considers the unification question, cosmological implications, current and future detectors, and current status of knowledge on proton decay. (JN)

  17. Statistical behavior of proton and electron auroras during substorms

    NASA Astrophysics Data System (ADS)

    Mende, S. B.; Frey, H. U.; Morsony, B. J.; Immel, T. J.

    2003-09-01

    The substorm evolution was studied by performing a superposed epoch analysis of 91 substorms using IMAGE FUV data. Onset locations and times were determined from images produced by the Wideband Imaging Camera (WIC) usually dominated by electron aurora. Images taken by WIC and by the Spectrographic Imager SI12 channel, responsive to proton aurora, were transformed into rectangular magnetic latitude (ML) and magnetic local time (MLT) coordinates and plotted on a timescale related to the time of substorm onset (T = 0) and to a Relative MLT (RMLT) normalized to onset MLT. A double Gaussian was fitted to the auroral intensity data as a function of ML at RMLT of -4, -2, 0, +2, and +4. From the Gaussian coefficients the means of several parameters were plotted as a function of time. Presubstorm, there was an equatorward motion of the mean low-latitude boundary of the electron and proton aurora. There was no evidence of preonset auroral fading in the mean intensity. At onset the proton auroral peak intensity increased only by a factor of 2 compared with 5 for the electrons. At RMLT = 0, rapid poleward expansion of the proton aurora after onset occurred. The proton expansion slowed down after the first few minutes, while the electron surge continued toward higher latitudes. The mean poleward expansion of the electron aurora reached about 3.5 in 5 min and reached a total expansion of 5.5 in an hour. The protons expanded about 2.5 in 5 min and expanded about 3 one hour after onset. The latitude width of the aurora increased at onset due to both a large poleward and a moderate equatorward expansion. There appeared to be stronger substorm-related activity in the local time range toward dawn than toward dusk. In the RMLT sector duskward of onset the proton auroras were located equatorward of the electrons and poleward in the dawnward RMLT sector.

  18. Proton Dispersion Forces

    PubMed Central

    Zundel, G.; Lubos, W. D.; Klkenbeck, K.

    1972-01-01

    In the double helix formed by the semiprotonated polycytidylic acid (poly C), both strands are linked via NH+...N hydrogen bonds. It is a known fact that such symmetrical hydrogen bonds with a double minimum potential well are extremely polarizable. This polarizability causes interaction effects, in particular the proton dispersion forces between such hydrogen bonds. These forces result in a shift of the energy levels and a continuum is observed in the infrared (IR) spectra of solutions in which such hydrogen bonds are present. The continuum occurs in the IR spectrum of the semiprotonated poly C, when the former is present in coiled state. If the double helix forms, an extremely broad band of the NH stretching vibration is observed instead of the continuum, since in the double helix all hydrogen bonds are oriented equally to one another and polarize each other mutually to a strong degree. The proton dispersion forces between the hydrogen bonds balance a considerable part of the electrostatic repulsion of the protons and hence enable the double helix to form. It is conceivable that an unsymmetrical double minimum potential well is present in the NH...N bonds in the DNA and RNA. Such bonds may likewise be considerably more polarizable than electron systems and thus, in this case too, proton dispersion forces would contribute to helix stabilization. PMID:4642224

  19. Proton bunch compression strategies

    SciTech Connect

    Lebedev, Valeri; /Fermilab

    2009-10-01

    The paper discusses main limitations on the beam power and other machine parameters for a 4 MW proton driver for muon collider. The strongest limitation comes from a longitudinal microwave instability limiting the beam power to about 1 MW for an 8 GeV compressor ring.

  20. High Power Proton Facilities

    NASA Astrophysics Data System (ADS)

    Nagaitsev, Sergei

    2015-04-01

    This presentation will provide an overview of the capabilities and challenges of high intensity proton accelerators, such as J-PARC, Fermilab MI, SNS, ISIS, PSI, ESS (in the future) and others. The presentation will focus on lessons learned, new concepts, beam loss mechanisms and methods to mitigate them.

  1. Proton-transfer laser

    SciTech Connect

    Acuna, A.U.; Costela, A.; Munoz, J.M.

    1986-06-19

    Stimulated radiation was generated by an active medium where the population inversion results from excited-state intramolecular proton-transfer reaction. The operation of a salicylamide pulsed laser, built on this principle, is described. The laser shows a 5% energy conversion efficiency when pumped with 5-20 mJ of 308-nm radiation.

  2. Proton radiography and proton computed tomography based on time-resolved dose measurements

    NASA Astrophysics Data System (ADS)

    Testa, Mauro; Verburg, Joost M.; Rose, Mark; Min, Chul Hee; Tang, Shikui; Hassane Bentefour, El; Paganetti, Harald; Lu, Hsiao-Ming

    2013-11-01

    We present a proof of principle study of proton radiography and proton computed tomography (pCT) based on time-resolved dose measurements. We used a prototype, two-dimensional, diode-array detector capable of fast dose rate measurements, to acquire proton radiographic images expressed directly in water equivalent path length (WEPL). The technique is based on the time dependence of the dose distribution delivered by a proton beam traversing a range modulator wheel in passive scattering proton therapy systems. The dose rate produced in the medium by such a system is periodic and has a unique pattern in time at each point along the beam path and thus encodes the WEPL. By measuring the time dose pattern at the point of interest, the WEPL to this point can be decoded. If one measures the time-dose patterns at points on a plane behind the patient for a beam with sufficient energy to penetrate the patient, the obtained 2D distribution of the WEPL forms an image. The technique requires only a 2D dosimeter array and it uses only the clinical beam for a fraction of second with negligible dose to patient. We first evaluated the accuracy of the technique in determining the WEPL for static phantoms aiming at beam range verification of the brain fields of medulloblastoma patients. Accurate beam ranges for these fields can significantly reduce the dose to the cranial skin of the patient and thus the risk of permanent alopecia. Second, we investigated the potential features of the technique for real-time imaging of a moving phantom. Real-time tumor tracking by proton radiography could provide more accurate validations of tumor motion models due to the more sensitive dependence of proton beam on tissue density compared to x-rays. Our radiographic technique is rapid (˜100 ms) and simultaneous over the whole field, it can image mobile tumors without the problem of interplay effect inherently challenging for methods based on pencil beams. Third, we present the reconstructed pCT images of a cylindrical phantom containing inserts of different materials. As for all conventional pCT systems, the method illustrated in this work produces tomographic images that are potentially more accurate than x-ray CT in providing maps of proton relative stopping power (RSP) in the patient without the need for converting x-ray Hounsfield units to proton RSP. All phantom tests produced reasonable results, given the currently limited spatial and time resolution of the prototype detector. The dose required to produce one radiographic image, with the current settings, is ˜0.7 cGy. Finally, we discuss a series of techniques to improve the resolution and accuracy of radiographic and tomographic images for the future development of a full-scale detector.

  3. Filtered backprojection proton CT reconstruction along most likely paths

    SciTech Connect

    Rit, Simon; Dedes, George; Freud, Nicolas; Sarrut, David; Letang, Jean Michel

    2013-03-15

    Purpose: Proton CT (pCT) has the potential to accurately measure the electron density map of tissues at low doses but the spatial resolution is prohibitive if the curved paths of protons in matter is not accounted for. The authors propose to account for an estimate of the most likely path of protons in a filtered backprojection (FBP) reconstruction algorithm. Methods: The energy loss of protons is first binned in several proton radiographs at different distances to the proton source to exploit the depth-dependency of the estimate of the most likely path. This process is named the distance-driven binning. A voxel-specific backprojection is then used to select the adequate radiograph in the distance-driven binning in order to propagate in the pCT image the best achievable spatial resolution in proton radiographs. The improvement in spatial resolution is demonstrated using Monte Carlo simulations of resolution phantoms. Results: The spatial resolution in the distance-driven binning depended on the distance of the objects from the source and was optimal in the binned radiograph corresponding to that distance. The spatial resolution in the reconstructed pCT images decreased with the depth in the scanned object but it was always better than previous FBP algorithms assuming straight line paths. In a water cylinder with 20 cm diameter, the observed range of spatial resolutions was 0.7 - 1.6 mm compared to 1.0 - 2.4 mm at best with a straight line path assumption. The improvement was strongly enhanced in shorter 200 Degree-Sign scans. Conclusions: Improved spatial resolution was obtained in pCT images with filtered backprojection reconstruction using most likely path estimates of protons. The improvement in spatial resolution combined with the practicality of FBP algorithms compared to iterative reconstruction algorithms makes this new algorithm a candidate of choice for clinical pCT.

  4. Proton computed tomography from multiple physics processes

    NASA Astrophysics Data System (ADS)

    Bopp, C.; Colin, J.; Cussol, D.; Finck, Ch; Labalme, M.; Rousseau, M.; Brasse, D.

    2013-10-01

    Proton CT (pCT) nowadays aims at improving hadron therapy treatment planning by mapping the relative stopping power (RSP) of materials with respect to water. The RSP depends mainly on the electron density of the materials. The main information used is the energy of the protons. However, during a pCT acquisition, the spatial and angular deviation of each particle is recorded and the information about its transmission is implicitly available. The potential use of those observables in order to get information about the materials is being investigated. Monte Carlo simulations of protons sent into homogeneous materials were performed, and the influence of the chemical composition on the outputs was studied. A pCT acquisition of a head phantom scan was simulated. Brain lesions with the same electron density but different concentrations of oxygen were used to evaluate the different observables. Tomographic images from the different physics processes were reconstructed using a filtered back-projection algorithm. Preliminary results indicate that information is present in the reconstructed images of transmission and angular deviation that may help differentiate tissues. However, the statistical uncertainty on these observables generates further challenge in order to obtain an optimal reconstruction and extract the most pertinent information.

  5. Study of spatial resolution of proton computed tomography using a silicon strip detector

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Izumikawa, T.; Goto, J.; Kawasaki, T.; Kimura, T.

    2014-01-01

    Proton computed tomography (CT) is an imaging technique using a high-energy proton beam penetrating the human body and shows promise for improving the quality of cancer therapy with high-energy particle beams because more accurate electron density distribution measurements can be achieved with proton CT. The deterioration of the spatial resolution owing to multiple Coulomb scattering is, however, a crucial issue. The control of the radiation dose and the long exposure time are also problems to be solved. We have developed a prototype system for proton CT with a silicon strip detector and performed a beam test for imaging. The distribution of the electron density has been measured precisely. We also demonstrated an improvement in spatial resolution by reconstructing the proton trajectory. A spatial resolution of 0.45 mm is achieved for a 25-mm-thick polyethylene object. This will be a useful result for upgrading proton CT application for practical use.

  6. Validating the predicted lateral straggling of MeV-energy proton beams.

    SciTech Connect

    Felter, Thomas E.; Antolak, Arlyn J.; Bench, Graham

    2004-02-01

    Proton imaging is a potential nondestructive method for characterizing NIF (National Ignition Facility) targets in two- and three-dimensions with micron-scale spatial resolution. The main limitation for high resolution imaging with proton beams, especially for thick samples, is the positional blurring of the proton beam, known as 'lateral straggling'. Accurate prediction of the amount of lateral straggling and, consequently, the achievable spatial resolution in pertinent NIF target material combinations and geometries requires validated proton transport models. We present results of Monte Carlo simulations of MeV-energy proton transport through thin ({approx}1 micron thick) metal foils. The calculated residual proton distributions are compared to recent lateral straggling measurements obtained at the LLNL 4-MV Pelletron accelerator.

  7. Smashing Protons to Smithereens

    ScienceCinema

    Marc-André Pleier

    2010-09-01

    Pleier discusses the extraordinary research taking place at the Large Hadron Collider (LHC) ? the world?s newest, biggest, and highest energy particle accelerator located at CERN. Pleier is one of hundreds of researchers from around the world working on ATLAS, a seven-story particle detector positioned at a point where the LHC?s oppositely circulating beams of protons slam into one another head-on.

  8. Smashing Protons to Smithereens

    SciTech Connect

    Marc-André Pleier

    2010-05-05

    Pleier discusses the extraordinary research taking place at the Large Hadron Collider (LHC) — the world’s newest, biggest, and highest energy particle accelerator located at CERN. Pleier is one of hundreds of researchers from around the world working on ATLAS, a seven-story particle detector positioned at a point where the LHC’s oppositely circulating beams of protons slam into one another head-on.

  9. Ionospherically reflected proton whistlers

    NASA Astrophysics Data System (ADS)

    Vavilov, D. I.; Shklyar, D. R.

    2014-12-01

    We present experimental observations and detailed investigation of the variety of proton whistlers that includes transequatorial and ionospherically reflected proton whistlers. The latter have previously been indicated from numerical modeling of spectrograms. The study is based on six-component ELF wave data from the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite which permits to obtain not only spectrograms displaying the power spectral density but also such wave properties as the polarization, wave normal angle, wave refractive index, and normalized parallel component of the Poynting vector. The explanation of various types of proton whistlers is based on the properties of ion cyclotron wave propagation in a multicomponent magnetoplasma, with special consideration of the effect of ion hybrid resonance reflection. Analysis of experimental data is supplemented by numerical modeling of spectrograms that reproduces the main features of experimental ones. As a self-contained result, we provide conclusive experimental evidences that the region illuminated by a lightning stroke in the Earth-ionosphere waveguide may spread over a distance of 4000 km in both hemispheres.

  10. "Decoupled" Proton NMR Spectra

    NASA Astrophysics Data System (ADS)

    Woodley, M.; Freeman, R.

    High-resolution proton NMR spectra are recorded in a new form where all resonances are singlets at the chemical-shift frequencies, with no spin-spin splittings. These "decoupled" proton spectra are derived from two-dimensional J spectra after real Fourier transformation (without frequency discrimination in F1) so that each spin multiplet lies along both the 45° and the 135° diagonal, forming a pattern similar to St. Andrew's cross, with C 4 symmetry. The chemical shifts are located by searching for these centers of symmetry with a postacquisition data-processing algorithm. This is designed to facilitate the separation of overlapping and interpenetrating spin multiplets. The method is illustrated with applications to the 400 MHz high-resolution proton spectra of dehydrotestosterone and 4-androsten-3,17-dione. It is also possible to separate the spectra of components in a mixture and this is illustrated by breaking down the spectrum of an aqueous solution of D-glucose into subspectra from the α and β anomers, in order to follow the time evolution of the mutarotation.

  11. Pion, Kaon, Proton and Antiproton Production in Proton-Proton Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Blattnig, Steve R.

    2008-01-01

    Inclusive pion, kaon, proton, and antiproton production from proton-proton collisions is studied at a variety of proton energies. Various available parameterizations of Lorentz-invariant differential cross sections as a function of transverse momentum and rapidity are compared with experimental data. The Badhwar and Alper parameterizations are moderately satisfactory for charged pion production. The Badhwar parameterization provides the best fit for charged kaon production. For proton production, the Alper parameterization is best, and for antiproton production the Carey parameterization works best. However, no parameterization is able to fully account for all the data.

  12. First measurements of laser-accelerated proton induced luminescence

    SciTech Connect

    Floquet, V.; Ceccotti, T.; Dobosz Dufrenoy, S.; Bonnaud, G.; Monot, P.; Martin, Ph.; Gremillet, L.

    2012-09-15

    We present our first results about laser-accelerated proton induced luminescence in solids. In the first part, we describe the optimization of the proton source as a function of the target thickness as well as the laser pulse duration and energy. Due to the ultra high contrast ratio of our laser beam, we succeeded in using targets ranging from the micron scale down to nanometers thickness. The two optimal thicknesses we put in evidence are in good agreement with numerical simulations. Laser pulse duration shows a small influence on proton maximum energy, whereas the latter turns out to vary almost linearly as a function of laser energy. Thanks to this optimisation work, we have been able to acquire images of the proton energy deposition in a solid scintillator.

  13. Protonation of heterocyclic aromatic molecules

    NASA Astrophysics Data System (ADS)

    Lorenz, Ulrich Joseph; Lemaire, Joel; Maitre, Philippe; Crestoni, Maria-Elisa; Fornarini, Simonetta; Dopfer, Otto

    2007-11-01

    Protonated furan (C4H5O+, furanH+) and protonated pyrrole (C4H6N+, pyrroleH+) are generated by chemical ionization of the respective parent molecules in the cell of an FT-ICR mass spectrometer using CH5+/C2H5+ as protonating agents. The protonation site is investigated by resonant infrared multiphoton dissociation (IRMPD) spectroscopy in the 900-1700 cm-1 fingerprint range employing the free electron laser (FEL) at the Centre Laser Infrarouge Orsay (CLIO). Comparison with quantum chemical calculations at the B3LYP/6-311G(2df, 2pd) level of theory demonstrates unambiguously that only the C[alpha] protonated isomers are observed, which correspond to the global minima on the potential energy surfaces of both protonated heterocyclic molecules. Spectroscopic features corresponding to protonation at the C[beta] atom or at the heteroatom are not detected. The IRMPD spectra correspond to the first spectroscopic identification of both protonated heterocyclic molecules in the gas phase. During the course of the experiments, the IRMPD spectrum of the furan radical cation (C4H4O+, furan+) has been detected as well. Comparison of the IR spectra of the neutral molecules with the IRMPD spectra of the radical cation and the protonated species reveals the effects of both ionization and protonation on the structural properties of these fundamental heterocyclic molecules.

  14. Nuclear spin noise imaging.

    PubMed

    Mller, Norbert; Jerschow, Alexej

    2006-05-01

    NMR images were obtained from the proton spin noise signals of a water-containing phantom, which was placed in the highly tuned, low-noise resonant circuit of a cryogenically cooled NMR probe in the presence of systematically varied magnetic field gradients. The spatially resolved proton spin density was obtained from the raw signal by a modified projection-reconstruction protocol. Although spin noise imaging is inherently less sensitive than conventional magnetic resonance imaging, it affords an entirely noninvasive visualization of the interior of opaque objects or subjects. Thus, tomography becomes possible even when neither x-ray nor radio frequency radiation can be applied for technical or safety reasons. PMID:16636281

  15. Structural Investigation of Protonated Azidothymidine and Protonated Dimer

    NASA Astrophysics Data System (ADS)

    Ziegler, Blake E.; Marta, Rick A.; Burt, Michael B.; Martens, Sabrina M.; Martens, Jonathan K.; McMahon, Terry B.

    2013-12-01

    Infrared multiple photon dissociation (IRMPD) spectroscopy experiments and quantum chemical calculations have been used to explore the possible structures of protonated azidothymidine and the corresponding protonated dimer. Many interesting differences between the protonated and neutral forms of azidothymidine were found, particularly associated with keto-enol tautomerization. Comparison of computational vibrational and the experimental IMRPD spectra show good agreement and give confidence that the dominant protonated species has been identified. The protonated dimer of azidothymidine exhibits three intramolecular hydrogen bonds. The IRMPD spectrum of the protonated dimer is consistent with the spectrum of the most stable computational structure. This work brings to light interesting keto-enol tautomerization and exocyclic hydrogen bonding involving azidothymidine and its protonated dimer. The fact that one dominant protonated species is observed in the gas phase, despite both the keto and enol structures being similar in energy, is proposed to be the direct result of the electrospray ionization process in which the dominant protonated dimer structure dissociates in the most energetically favorable way.

  16. Differential Cross Sections for Proton-Proton Elastic Scattering

    NASA Technical Reports Server (NTRS)

    Norman, Ryan B.; Dick, Frank; Norbury, John W.; Blattnig, Steve R.

    2009-01-01

    Proton-proton elastic scattering is investigated within the framework of the one pion exchange model in an attempt to model nucleon-nucleon interactions spanning the large range of energies important to cosmic ray shielding. A quantum field theoretic calculation is used to compute both differential and total cross sections. A scalar theory is then presented and compared to the one pion exchange model. The theoretical cross sections are compared to proton-proton scattering data to determine the validity of the models.

  17. Modeling the electromagnetic ion cyclotron wave-induced formation of detached subauroral proton arcs

    NASA Astrophysics Data System (ADS)

    Jordanova, V. K.; Spasojevic, M.; Thomsen, M. F.

    2007-08-01

    Detached dayside proton arcs have been recently observed at Earth with the IMAGE FUV instrument as subauroral arcs separated from the main oval and extending over several hours of local time in the afternoon sector. We investigate the mechanisms causing the proton precipitation during two subauroral arc events that occurred on 23 January 2001 and 18 June 2001. We employ our kinetic physics-based model coupled with a dynamic plasmasphere model and calculate the growth rate of electromagnetic ion cyclotron (EMIC) waves self-consistently with the evolving ring current H+, O+, and He+ ion distributions. Modeled plasmaspheric densities agree well with in situ observations from geosynchronous LANL satellites and duskside plasmapause observations from IMAGE EUV but overestimate the drainage plume extent toward noon on 18 June. Global images of precipitating H+ ions are obtained and compared with IMAGE observations of proton arcs. We find that EMIC waves are preferentially excited, and proton precipitation maximizes, within regions of spatial overlap of energetic ring current protons and dayside plasmaspheric plumes and along steep density gradients at the plasmapause. The model matches very well the temporal and spatial evolution of FUV observations on 23 January. The predicted location of the proton precipitation on 18 June extends a few hours westward of the observations, and an offset of 2 hours in the convection electric field is needed to reproduce well the evolution of the proton arc. This study indicates that cyclotron resonant wave-particle interactions are a viable mechanism for the generation of subauroral proton arcs.

  18. Computer Simulations of Proton Channels

    NASA Astrophysics Data System (ADS)

    Voth, Gregory A.

    2002-03-01

    A theoretical and computer simulation model of proton transport through gramicidin A, synthetic leucine-serine ion channels, and the M2 proton channel of the influenza A virus will be presented. Insight will be given into the atomistic factors which determine the proton transport rate and the mechanism(s) for the proton hopping process. The possible role of the protonation/deprotonation of histidine groups in the M2 channel will also be considered. In all cases, the likely origin of the activation free energy barriers and the anisotropic diffusion properties will be discussed. The modeling of the excess proton and its interaction with its surroundings will be presented based on a novel multi-state empirical valence bond force field approach which has been implemented within a biomolecular MD simulation code.

  19. Changes in water content and distribution in Quercus ilex leaves during progressive drought assessed by in vivo 1H magnetic resonance imaging

    PubMed Central

    2010-01-01

    Background Drought is a common stressor in many regions of the world and current climatic global circulation models predict further increases in warming and drought in the coming decades in several of these regions, such as the Mediterranean basin. The changes in leaf water content, distribution and dynamics in plant tissues under different soil water availabilities are not well known. In order to fill this gap, in the present report we describe our study withholding the irrigation of the seedlings of Quercus ilex, the dominant tree species in the evergreen forests of many areas of the Mediterranean Basin. We have monitored the gradual changes in water content in the different leaf areas, in vivo and non-invasively, by 1H magnetic resonance imaging (MRI) using proton density weighted (?w) images and spin-spin relaxation time (T2) maps. Results ?w images showed that the distal leaf area lost water faster than the basal area and that after four weeks of similar losses, the water reduction was greater in leaf veins than in leaf parenchyma areas and also in distal than in basal leaf area. There was a similar tendency in all different areas and tissues, of increasing T2 values during the drought period. This indicates an increase in the dynamics of free water, suggesting a decrease of cell membranes permeability. Conclusions The results indicate a non homogeneous leaf response to stress with a differentiated capacity to mobilize water between its different parts and tissues. This study shows that the MRI technique can be a useful tool to follow non-intrusively the in vivo water content changes in the different parts of the leaves during drought stress. It opens up new possibilities to better characterize the associated physiological changes and provides important information about the different responses of the different leaf areas what should be taken into account when conducting physiological and metabolic drought stress studies in different parts of the leaves during drought stress. PMID:20735815

  20. Proton irradiation and endometriosis

    SciTech Connect

    Wood, D.H.; Yochmowitz, M.G.; Salmon, Y.L.; Eason, R.L.; Boster, R.A.

    1983-08-01

    Female rhesus monkeys given single total-body exposures of protons of varying energies developed endometriosis at a frequency significantly higher than that of nonirradiated animals of the same age. The minimum latency period was 7 years after exposure. The doses and energies of the radiation received were within the range that could be received by an aircrew member in near-earth orbit during a random solar flare event, leading to the conclusion that endometriosis should be a consideration in assessing the risk of delayed radiation effects in female crewmembers.

  1. Proton Size Anomaly

    SciTech Connect

    Barger, Vernon; Chiang, Cheng-Wei; Keung, Wai-Yee; Marfatia, Danny

    2011-04-15

    A measurement of the Lamb shift in muonic hydrogen yields a charge radius of the proton that is smaller than the CODATA value by about 5 standard deviations. We explore the possibility that new scalar, pseudoscalar, vector, and tensor flavor-conserving nonuniversal interactions may be responsible for the discrepancy. We consider exotic particles that, among leptons, couple preferentially to muons and mediate an attractive nucleon-muon interaction. We find that the many constraints from low energy data disfavor new spin-0, spin-1, and spin-2 particles as an explanation.

  2. Spin of the proton

    SciTech Connect

    Nathan Isgur

    1996-12-01

    The author argues that their response to the spin crisis should not be to abandon the naive quark model baby, but rather to allow it to mature. In particular, he advocates dressing the baby in qq pairs, first showing that this can be done without compromising the naive quark model's success with either spectroscopy or the OZI rule. Finally, he shows that despite their near invisibility elsewhere, pairs do play an important role in the proton's spin structure by creating an antipolarized qq sea. In the context of an explicit calculation he demonstrates that it is plausible that the entire ''spin crisis'' arises from this effect.

  3. Proton Upset Monte Carlo Simulation

    NASA Technical Reports Server (NTRS)

    O'Neill, Patrick M.; Kouba, Coy K.; Foster, Charles C.

    2009-01-01

    The Proton Upset Monte Carlo Simulation (PROPSET) program calculates the frequency of on-orbit upsets in computer chips (for given orbits such as Low Earth Orbit, Lunar Orbit, and the like) from proton bombardment based on the results of heavy ion testing alone. The software simulates the bombardment of modern microelectronic components (computer chips) with high-energy (.200 MeV) protons. The nuclear interaction of the proton with the silicon of the chip is modeled and nuclear fragments from this interaction are tracked using Monte Carlo techniques to produce statistically accurate predictions.

  4. Proton MRS in neurological disorders.

    PubMed

    Bonavita, S; Di Salle, F; Tedeschi, G

    1999-05-01

    Proton magnetic resonance spectroscopy (1H MRS) permits the acquisition of the signal arising from several brain metabolites. At long echo-time (TE) 1H MRS can detect N-acetyl-aspartate containing compounds, choline containing compounds, creatine + phosphocreatine and lactate. At short TE, lipids, tryglicerides, alanine, glutamate, glutamine, GABA, scyllo-inositol, glucose, myo-inositol, carnosine and histydine are visible. 1H MRS can be performed with single-voxel, multivoxel, single slice and multislice techniques. With single voxel 1H MRS it is possible to measure metabolites relaxation time, which allows the measurement of metabolite concentrations. This technique can be useful in the study of focal lesions in the central nervous system (CNS) such as epilepsy (pre-surgical identification of epileptic focus), brain tumors (evaluation of recurrence and radiation necrosis), stroke, multiple sclerosis, etc. Single slice and multislice 1H MRS imaging (1H MRSI) can be performed only at long TE and permits the mapping of the brain metabolites distribution which makes them particularly useful in studying diffuse diseases and heterogeneous lesions of the CNS. 1H MRS can also be useful in the evaluation of 'ischemic penumbra' of stroke; developmental (myelin and neuronal dysgenesis); head trauma (evaluation of cerebral damage not visible with MRI); degenerative disorders (identification of microscopic pathology not visible with MRI); and metabolic diseases (metabolic disturbances with specific metabolic patterns). PMID:10401593

  5. Proton-air and proton-proton cross sections from air shower data

    NASA Technical Reports Server (NTRS)

    Linsley, J.

    1985-01-01

    Data on the fluctuations in depth of maximum development of cosmic ray air showers, corrected for the effects of mixed primary composition and shower development fluctuations, yield values of the inelastic proton-air cross section for laboratory energies in the range 10 to the 8th power to 10 to the 10th power GeV. From these values of proton-air cross section, corresponding values of the proton-proton total cross section are derived by means of Glauber theory and geometrical scaling. The resulting values of proton-proton cross section are inconsistent with a well known 1n(2)s extrapolation of ISR data which is consistent with SPS data; they indicate a less rapid rate of increase in the interval 540 sq root of s 100000 GeV.

  6. Proton in SRF Niobium

    SciTech Connect

    Wallace, John Paul

    2011-03-31

    Hydrogen is a difficult impurity to physically deal with in superconducting radio frequency (SRF) niobium, therefore, its properties in the metals should be well understood to allow the metal's superconducting properties to be optimized for minimum loss in the construction of resonant accelerator cavities. It is known that hydrogen is a paramagnetic impurity in niobium from NMR studies. This paramagnetism and its effect on superconducting properties are important to understand. To that end analytical induction measurements aimed at isolating the magnetic properties of hydrogen in SRF niobium are introduced along with optical reflection spectroscopy which is also sensitive to the presence of hydrogen. From the variety, magnitude and rapid kinetics found in the optical and magnetic properties of niobium contaminated with hydrogen forced a search for an atomic model. This yielded quantum mechanical description that correctly generates the activation energy for diffusion of the proton and its isotopes not only in niobium but the remaining metals for which data is available. This interpretation provides a frame work for understanding the individual and collective behavior of protons in metals.

  7. Proton in SRF Niobium

    NASA Astrophysics Data System (ADS)

    Wallace, John Paul

    2011-03-01

    Hydrogen is a difficult impurity to physically deal with in superconducting radio frequency (SRF) niobium, therefore, its properties in the metals should be well understood to allow the metal's superconducting properties to be optimized for minimum loss in the construction of resonant accelerator cavities. It is known that hydrogen is a paramagnetic impurity in niobium from NMR studies. This paramagnetism and its effect on superconducting properties are important to understand. To that end analytical induction measurements aimed at isolating the magnetic properties of hydrogen in SRF niobium are introduced along with optical reflection spectroscopy which is also sensitive to the presence of hydrogen. From the variety, magnitude and rapid kinetics found in the optical and magnetic properties of niobium contaminated with hydrogen forced a search for an atomic model. This yielded quantum mechanical description that correctly generates the activation energy for diffusion of the proton and its isotopes not only in niobium but the remaining metals for which data is available. This interpretation provides a frame work for understanding the individual and collective behavior of protons in metals.

  8. Berkeley Proton Linear Accelerator

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  9. Fractionated proton beam irradiation of pituitary adenomas

    SciTech Connect

    Ronson, Brian B.; Schulte, Reinhard W.; Han, Khanh P.; Loredo, Lilia N.; Slater, James M.; Slater, Jerry D. . E-mail: jdslater@dominion.llumc.edu

    2006-02-01

    Purpose: Various radiation techniques and modalities have been used to treat pituitary adenomas. This report details our experience with proton treatment of these tumors. Methods and Materials: Forty-seven patients with pituitary adenomas treated with protons, who had at least 6 months of follow-up, were included in this analysis. Forty-two patients underwent a prior surgical resection; 5 were treated with primary radiation. Approximately half the tumors were functional. The median dose was 54 cobalt-gray equivalent. Results: Tumor stabilization occurred in all 41 patients available for follow-up imaging; 10 patients had no residual tumor, and 3 had greater than 50% reduction in tumor size. Seventeen patients with functional adenomas had normalized or decreased hormone levels; progression occurred in 3 patients. Six patients have died; 2 deaths were attributed to functional progression. Complications included temporal lobe necrosis in 1 patient, new significant visual deficits in 3 patients, and incident hypopituitarism in 11 patients. Conclusion: Fractionated conformal proton-beam irradiation achieved effective radiologic, endocrinological, and symptomatic control of pituitary adenomas. Significant morbidity was uncommon, with the exception of postradiation hypopituitarism, which we attribute in part to concomitant risk factors for hypopituitarism present in our patient population.

  10. Umbrella sampling of proton transfer in a creatine-water system

    NASA Astrophysics Data System (ADS)

    Ivchenko, Olga; Bachert, Peter; Imhof, Petra

    2014-04-01

    Proton transfer reactions are among the most common processes in chemistry and biology. Proton transfer between creatine and surrounding solvent water is underlying the chemical exchange saturation transfer used as a contrast in magnetic resonance imaging. The free energy barrier, determined by first-principles umbrella sampling simulations (EaDFT 3 kcal/mol) is in the same order of magnitude as the experimentally obtained activation energy. The underlying mechanism is a first proton transfer from the guanidinium group to the water pool, followed by a second transition where a proton is "transferred back" from the nearest water molecule to the deprotonated nitrogen atom of creatine.

  11. SU-E-J-144: MRI Visualization of a Metallic Fiducial Marker Used for Image Guided Prostate Radiotherapy

    SciTech Connect

    Yee, S; Krauss, D; Yan, D

    2014-06-01

    Purpose: Unlike on the daily CBCT used for the image-guided radiation therapy, the visualization of an implantable metallic fiducial marker on the planning MRI images has been a challenge due to the inherent insensitivity of metal in MRI, and very thin (? 1 mm or less) diameter. Here, an MRI technique to visualize a marker used for prostate cancer radiotherapy is reported. Methods: During the MRI acquisitions, a multi-shot turbo spin echo (TSE) technique (TR=3500 ms, TE=8.6 ms, ETL=17, recon voxel=0.42x0.42x3.5 mm3) was acquired in Philips 3T Ingenia together with a T2-weighted multi-shot TSE (TR=5381 ms, TE=110 ms, ETL=17, recon voxel=0.470.473 mm3) and a balanced turbo field echo (bTFE, flip angle 60, TR=2.76 ms, TE=1.3 ms, 0.850.853 mm3, NSA=4). In acquiring the MRI to visualize the fiducial marker, a particular emphasis was made to improve the spatial resolution and visibility in the generally dark, inhomogeneous prostate area by adjusting the slice profile ordering and TE values of TSE acquisition (in general, the lower value of TE in TSE acquisition generates a brighter signal but at the cost of high spatial resolution since the k-space, responsible for high spatial resolution, is filled with noisier data). Results: While clearly visible in CT, the marker was not visible in either T2-weighted TSE or bTFE, although the image qualities of both images were superior. In the new TSE acquisition (? a proton-density weighted image) adjusted by changing the profile ordering and the TE value, the marker was visible as a negative (but clear) contrast in the magnitude MRI, and as a positive contrast in the imaginary image of the phase-sensitive MRI. Conclusion: A metallic fiducial marker used for image guidance before prostate cancer radiotherapy can be made visible in MRI, which may facilitate more use of MRI in planning and guiding such radiation therapy.

  12. TU-A-9A-09: Proton Beam X-Ray Fluorescence CT

    SciTech Connect

    Bazalova, M; Ahmad, M; Fahrig, R; Xing, L

    2014-06-15

    Purpose: To evaluate x-ray fluorescence computed tomography induced with proton beams (pXFCT) for imaging of gold contrast agent. Methods: Proton-induced x-ray fluorescence was studied by means of Monte Carlo (MC) simulations using TOPAS, a MC code based on GEANT4. First, proton-induced K-shell and L-shell fluorescence was studied as a function of proton beam energy and 1) depth in water and 2) size of contrast object. Second, pXFCT images of a 2-cm diameter cylindrical phantom with four 5- mm diameter contrast vials and of a 20-cm diameter phantom with 1-cm diameter vials were simulated. Contrast vials were filled with water and water solutions with 1-5% gold per weight. Proton beam energies were varied from 70-250MeV. pXFCT sinograms were generated based on the net number of gold K-shell or L-shell x-rays determined by interpolations from the neighboring 0.5keV energy bins of spectra collected with an idealized 4π detector. pXFCT images were reconstructed with filtered-back projection, and no attenuation correction was applied. Results: Proton induced x-ray fluorescence spectra showed very low background compared to x-ray induced fluorescence. Proton induced L-shell fluorescence had a higher cross-section compared to K-shell fluorescence. Excitation of L-shell fluorescence was most efficient for low-energy protons, i.e. at the Bragg peak. K-shell fluorescence increased with increasing proton beam energy and object size. The 2% and 5% gold contrast vials were accurately reconstructed in K-shell pXFCT images of both the 2-cm and 20-cm diameter phantoms. Small phantom L-shell pXFCT image required attenuation correction and had a higher sensitivity for 70MeV protons compared to 250MeV protons. With attenuation correction, L-shell pXFCT might be a feasible option for imaging of small size (∼2cm) objects. Imaging doses for all simulations were 5-30cGy. Conclusion: Proton induced x-ray fluorescence CT promises to be an alternative quantitative imaging technique to the commonly considered XFCT imaging with x-ray beams.

  13. Fan beam intensity modulated proton therapy

    NASA Astrophysics Data System (ADS)

    Hill, Patrick M.

    A fan beam proton therapy is developed which delivers intensity modulated proton therapy using distal edge tracking. The system may be retrofit onto existing proton therapy gantries without alterations to infrastructure in order to improve treatments through intensity modulation. A novel range and intensity modulation system is designed using acrylic leaves that are inserted or retracted from subsections of the fan beam. Leaf thicknesses are chosen in a base-2 system and motivated in a binary manner. Dose spots from individual beam channels range between 1 and 5 cm. Integrated collimators attempting to limit crosstalk among beam channels are investigated, but found to be inferior to uncollimated beam channel modulators. A treatment planning system performing data manipulation in MATLAB and dose calculation in MCNPX is developed. Beamlet dose is calculated on patient CT data and a fan beam source is manually defined to produce accurate results. An energy deposition tally follows the CT grid, allowing straightforward registration of dose and image data. Simulations of beam channels assume that a beam channel either delivers dose to a distal edge spot or is intensity modulated. A final calculation is performed separately to determine the deliverable dose accounting for all sources of scatter. Treatment plans investigate the effects that varying system parameters have on dose distributions. Beam channel apertures may be as large as 20 mm because the sharp distal falloff characteristic of proton dose provides sufficient intensity modulation to meet dose objectives, even in the presence of coarse lateral resolution. Dose conformity suffers only when treatments are delivered from less than 10 angles. Jaw widths of 1--2 cm produce comparable dose distributions, but a jaw width of 4 cm produces unacceptable target coverage when maintaining critical structure avoidance. Treatment time for a prostate delivery is estimated to be on the order of 10 minutes. Neutron production and dose estimates are found to be comparable to or slightly less than those found for existing passively scattered systems.

  14. Protonated pyrimidine-purine-purine triplex.

    PubMed Central

    Malkov, V A; Voloshin, O N; Veselkov, A G; Rostapshov, V M; Jansen, I; Soyfer, V N; Frank-Kamenetskii, M D

    1993-01-01

    We have studied a protonated pyrimidine-purine-purine (Py-Pu-Pu) triplex, which is formed between the d(C)nd(G)n duplex and the d(AG)m oligonucleotide as the third strand and carries the CG*A+ protonated base-triads. We have observed such an intermolecular complex between a plasmid carrying the d(C)18 d(G)18 insert and the d(AG)5 oligonucleotide without bivalent cations in 200 mM of Na+ at pH4.0. Bivalent cations additionally stabilize the complex. We propose the structures for nearly isomorphous base-triads TA*A, CG*G and CG*A+. To identify the H-DNA-like structure, which includes the triplex between d(C)n d(G)n duplex and the AG-strand, we have cloned in a superhelical plasmid the insert: G10TTAA(AG)5. The data on photofootprinting and chemical modification with diethyl pyrocarbonate, potassium permanganate and dimethyl sulfate demonstrate that the H-like structure with triplex carrying CG*G and CG*A+ base triads is actually formed under acid conditions. In the course of this study we have come across unexpected results on probing of Py-Pu-Pu triplexes by dimethyl sulfate (DMS): the protection effect is observed not only for guanines entering the duplex but also for guanines in the third strand lying in the major groove. We have demonstrated this effect not only for the case the novel protonated Py-Pu-Pu triplex but also for the traditional non-protonated Py-Pu-Pu intramolecular triplex (H*-DNA) formed by the d(C)37 d(G)37 insert in supercoiled plasmid in the presence of Mg2+ ions. Images PMID:8382787

  15. NMR imaging

    SciTech Connect

    Andrew, E.R.

    1983-04-01

    Since hydrogen is the most abundant element in all living organisms, proton NMR lends itself well as a method of investigation in biology and medicine. NMR imaging has some special advantages as a diagnostic tool: no ionizing radiation is used, it is noninvasive; it provides a safer means of imaging than the use of x-rays, gamma rays, positrons, or heavy ions. In contrast with ultrasound, the radiation penetrates the bony structures without attenuation. In additional to morphological information, NMR imaging provides additional diagnostic insights through relaxation parameters, which are not available from other imaging methods. In the decade since the first primitive NMR images were obtained, the quality of images now obtained approaches those from CT x-ray scanners. Prototype instruments are being constructed for clinical evaluation and the first whole-body scanners are beginning to appear on the market at costs comparable to CT scanners. Primary differences in equipment for conventional NMR and NMR imaging are the much larger aperture magnets that are required for the examination of human subjects and the addition of coils to generate field gradients and facilities for manipulating the gradients. Early results from clinical trials in many parts of the world are encouraging, and in a few years, the usefuleness of this modality of medical imaging to the medical profession in diagnosis and treatment of disease will be defined. 10 figures.

  16. Studies of electron and proton isochoric heating for fast ignition

    SciTech Connect

    Mackinnon, A; Key, M; Akli, K; Beg, F; Clarke, R; Clarke, D; Chen, M; Chung, H; Chen, S; Freeman, R; Green, J; Gu, P; Gregori, G; Highbarger, K; Habara, H; Hatchett, S; Hey, D; Heathcote, R; Hill, J; King, J; Kodama, R; Koch, J; Lancaster, K; Langdon, B; Murphy, C; Norreys, P; Neely, D; Nakatsutsumi, M; Nakamura, H; Patel, N; Patel, P; Pasley, J; Snavley, R; Stephens, R; Stoeckl, C; Foord, M; Tabak, M; Theobald, W; Storm, M; Tanaka, K; Tempo, M; Toley, M; Town, R; Wilks, S; VanWoerkom, L; Weber, R; Yabuuchi, T; Zhang, B

    2006-10-02

    Isochoric heating of inertially confined fusion plasmas by laser driven MeV electrons or protons is an area of great topical interest in the inertial confinement fusion community, particularly with respect to the fast ignition (FI) proposal to use this technique to initiate burn in a fusion capsule. Experiments designed to investigate electron isochoric heating have measured heating in two limiting cases of interest to fast ignition, small planar foils and hollow cones. Data from Cu K{alpha} fluorescence, crystal x-ray spectroscopy of Cu K shell emission, and XUV imaging at 68eV and 256 eV are used to test PIC and Hybrid PIC modeling of the interaction. Isochoric heating by focused proton beams generated at the concave inside surface of a hemi-shell and from a sub hemi-shell inside a cone have been studied with the same diagnostic methods plus imaging of proton induced K{alpha}. Conversion efficiency to protons has also been measured and modeled. Conclusions from the proton and electron heating experiments will be presented. Recent advances in modeling electron transport and innovative target designs for reducing igniter energy and increasing gain curves will also be discussed.

  17. ULF waves associated with enhanced subauroral proton precipitation

    NASA Astrophysics Data System (ADS)

    Immel, Thomas J.; Mende, S. B.; Frey, H. U.; Patel, J.; Bonnell, J. W.; Engebretson, M. J.; Fuselier, S. A.

    Several types of sub-auroral proton precipitation events have been identified using the Spectrographic Imager (SI) onboard the NASA-IMAGE satellite, including dayside subauroral proton flashes and detached proton arcs in the dusk sector. These have been observed at various levels of geomagnetic activity and solar wind conditions and the mechanism driving the precipitation has often been assumed to be scattering of protons into the loss cone by enhancement of ion-cyclotron waves in the interaction of the thermal plasmaspheric populations and more energetic ring current particles. Indeed, recent investigation of the detached arcs using the MPA instruments aboard the LANL geosynchronous satellites has shown there are nearly always heightened densities of cold plasma on high-altitude field lines which map down directly to the sub-auroral precipitation. If the ion-cyclotron instability is a causative mechanism, the enhancement of wave activity at ion-cyclotron frequencies should be measurable. It is here reported that magnetic pulsations in the Pc1 range occur in the vicinity of each of 4 detached arcs observed in 2000-2002, though with widely varying signatures. Additionally, longer period pulsations in the Pc5 ranges are also observed in the vicinity of the arcs, leading to the conclusion that a bounce-resonance of ring-current protons with the azimuthal Pc5 wave structure may also contribute to the detached precipitation.

  18. Proton Collimators for Fusion Reactors

    NASA Technical Reports Server (NTRS)

    Miley, George H.; Momota, Hiromu

    2003-01-01

    Proton collimators have been proposed for incorporation into inertial-electrostatic-confinement (IEC) fusion reactors. Such reactors have been envisioned as thrusters and sources of electric power for spacecraft and as sources of energetic protons in commercial ion-beam applications.

  19. Fragmentation pathways of protonated peptides.

    PubMed

    Paizs, Bla; Suhai, Sndor

    2005-01-01

    The fragmentation pathways of protonated peptides are reviewed in the present paper paying special attention to classification of the known fragmentation channels into a simple hierarchy defined according to the chemistry involved. It is shown that the 'mobile proton' model of peptide fragmentation can be used to understand the MS/MS spectra of protonated peptides only in a qualitative manner rationalizing differences observed for low-energy collision induced dissociation of peptide ions having or lacking a mobile proton. To overcome this limitation, a deeper understanding of the dissociation chemistry of protonated peptides is needed. To this end use of the 'pathways in competition' (PIC) model that involves a detailed energetic and kinetic characterization of the major peptide fragmentation pathways (PFPs) is proposed. The known PFPs are described in detail including all the pre-dissociation, dissociation, and post-dissociation events. It is our hope that studies to further extend PIC will lead to semi-quantative understanding of the MS/MS spectra of protonated peptides which could be used to develop refined bioinformatics algorithms for MS/MS based proteomics. Experimental and computational data on the fragmentation of protonated peptides are reevaluated from the point of view of the PIC model considering the mechanism, energetics, and kinetics of the major PFPs. Evidence proving semi-quantitative predictability of some of the ion intensity relationships (IIRs) of the MS/MS spectra of protonated peptides is presented. PMID:15389847

  20. First tests for an online treatment monitoring system with in-beam PET for proton therapy

    NASA Astrophysics Data System (ADS)

    Kraan, A. C.; Battistoni, G.; Belcari, N.; Camarlinghi, N.; Cappucci, F.; Ciocca, M.; Ferrari, A.; Ferretti, S.; Mairani, A.; Molinelli, S.; Pullia, M.; Retico, A.; Sala, P.; Sportelli, G.; Del Guerra, A.; Rosso, V.

    2015-01-01

    PET imaging is a non-invasive technique for particle range verification in proton therapy. It is based on measuring the β+ annihilations caused by nuclear interactions of the protons in the patient. In this work we present measurements for proton range verification in phantoms, performed at the CNAO particle therapy treatment center in Pavia, Italy, with our 10 × 10 cm2 planar PET prototype DoPET. PMMA phantoms were irradiated with mono-energetic proton beams and clinical treatment plans, and PET data were acquired during and shortly after proton irradiation. We created 1-D profiles of the β+ activity along the proton beam-axis, and evaluated the difference between the proximal rise and the distal fall-off position of the activity distribution. A good agreement with FLUKA Monte Carlo predictions was obtained. We also assessed the system response when the PMMA phantom contained an air cavity. The system was able to detect these cavities quickly after irradiation.

  1. Proton therapy for pancreatic cancer

    PubMed Central

    Nichols, Romaine C; Huh, Soon; Li, Zuofeng; Rutenberg, Michael

    2015-01-01

    Radiotherapy is commonly offered to patients with pancreatic malignancies although its ultimate utility is compromised since the pancreas is surrounded by exquisitely radiosensitive normal tissues, such as the duodenum, stomach, jejunum, liver, and kidneys. Proton radiotherapy can be used to create dose distributions that conform to tumor targets with significant normal tissue sparing. Because of this, protons appear to represent a superior modality for radiotherapy delivery to patients with unresectable tumors and those receiving postoperative radiotherapy. A particularly exciting opportunity for protons also exists for patients with resectable and marginally resectable disease. In this paper, we review the current literature on proton therapy for pancreatic cancer and discuss scenarios wherein the improvement in the therapeutic index with protons may have the potential to change the management paradigm for this malignancy. PMID:26380057

  2. Voltage-Gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2013-01-01

    The history of research on voltage-gated proton channels is recounted, from their proposed existence in dinoflagellates by Hastings in 1972 and their demonstration in snail neurons by Thomas and Meech in 1982, to the discovery (after a decade of controversy) of genes that unequivocally code for proton channels in 2006. Voltage-gated proton channels are perfectly selective for protons, conduct deuterons half as well, and the conductance is strongly temperature dependent. These properties are consistent with a conduction mechanism involving hydrogen-bonded-chain transfer, in which the selectivity filter is a titratable amino acid residue. Channel opening is regulated stringently by pH such that only outward current is normally activated. Main functions of proton channels include acid extrusion from cells and charge compensation for the electrogenic activity of the phagocyte NADPH oxidase. Genetic approaches hold the promise of rapid progress in the near future. PMID:18463791

  3. The proton (nuclear) microprobe

    NASA Astrophysics Data System (ADS)

    Legge, G. J. F.

    1989-04-01

    The scanning proton microprobe (SPMP) is closely related to the scanning electron microprobe (SEMP) or scanning electron microscope (SEM) with X-ray detector. Though the much greater elemental sensitivity of the SPMP is inherent in the physics, the generally inferior spatial resolution of the SPMP is not inherent and big improvements are possible, As its alternative name would imply, the SPMP is often used with heavier particle beams and with nuclear rather than atomic reactions. Its versatility and quantitative accuracy have justified greater instrumentation and computer power than that associated with other microprobes. It is fast becoming an industrially and commercially important instrument and there are few fields of scientific research in which it has not played a part. Notable contributions have been made in biology, medicine, agriculture, semiconductors, geology, mineralogy, extractive metallurgy, new materials, archaeology, forensic science, catalysis, industrial problems and reactor technology.

  4. Intravenous proton pump inhibitors.

    PubMed

    Baker, Danial E

    2006-01-01

    Intravenous (IV) administration of a proton pump inhibitor (PPI) is a faster way to achieve gastric acid suppression than oral administration of the same agent. Peak suppression after IV administration occurs within hours, compared with several days later after oral administration. Thus the IV route of administration offers a faster onset of gastric suppression, achievement of intragastric pH closer to neutrality, and better bioavailability. The PPIs that have IV formulations in the United States (esomeprazole, lansoprazole, and pantoprazole) are approved for different indications; the key differences among them relate to their ability to reach specific gastric pH, time to maintain a specific gastric pH, and ease of use of the IV formulation (eg, reconstitution, requirement of inline filters, infusion times). PMID:16520709

  5. Optical Diagnostics of Mercury Jet for an Intense Proton Target

    SciTech Connect

    Park, H; Tsang, T; Kirk, H.; Ladeinde, F; Graves, Van B; Spampinato, Philip Thomas; Carroll, Adam J; Titus, P; Mcdonald, K

    2008-01-01

    An optical diagnostic system is designed and constructed for imaging a free mercury jet interacting with a high intensity proton beam in a pulsed high-field solenoid magnet. The optical imaging system employs a back-illuminated, laser shadow photography technique. Object illumination and image capture are transmitted through radiation-hard multi-mode optical fibers and flexible coherent imaging fibers. A retro-reflected illumination design allows the entire passive imaging system to fit inside the bore of the solenoid magnet. A sequence of synchronized short laser light pulses are used to freeze the transient events, and the images are recorded by several high speed charge coupled devices. Quantitative and qualitative data analysis using image processing based on probability approach is described. The characteristics of free mercury jet as a high power target for beam-jet interaction at various level of the magnetic induction field is reported in this paper.

  6. Optical diagnostics of mercury jet for an intense proton target

    SciTech Connect

    Park, H.; Ladeinde, F.; Tsang, T.; Kirk, H. G.; Graves, V. B.; Spampinato, P. T.; Carroll, A. J.; Titus, P. H.; McDonald, K. T.

    2008-04-15

    An optical diagnostic system is designed and constructed for imaging a free mercury jet interacting with a high intensity proton beam in a pulsed high-field solenoid magnet. The optical imaging system employs a backilluminated, laser shadow photography technique. Object illumination and image capture are transmitted through radiation-hard multimode optical fibers and flexible coherent imaging fibers. A retroreflected illumination design allows the entire passive imaging system to fit inside the bore of the solenoid magnet. A sequence of synchronized short laser light pulses are used to freeze the transient events, and the images are recorded by several high speed charge coupled devices. Quantitative and qualitative data analysis using image processing based on probability approach is described. The characteristics of free mercury jet as a high power target for beam-jet interaction at various levels of the magnetic induction field is reported in this paper.

  7. Proton Radiography Peers into Metal Solidification

    PubMed Central

    Clarke, Amy; Imhoff, Seth; Gibbs, Paul; Cooley, Jason; Morris, Christopher; Merrill, Frank; Hollander, Brian; Mariam, Fesseha; Ott, Thomas; Barker, Martha; Tucker, Tim; Lee, Wah-Keat; Fezzaa, Kamel; Deriy, Alex; Patterson, Brian; Clarke, Kester; Montalvo, Joel; Field, Robert; Thoma, Dan; Smith, James; Teter, David

    2013-01-01

    Historically, metals are cut up and polished to see the structure and to infer how processing influences the evolution. We can now peer into a metal during processing without destroying it using proton radiography. Understanding the link between processing and structure is important because structure profoundly affects the properties of engineering materials. Synchrotron x-ray radiography has enabled real-time glimpses into metal solidification. However, x-ray energies favor the examination of small volumes and low density metals. Here we use high energy proton radiography for the first time to image a large metal volume (>10,000 mm3) during melting and solidification. We also show complementary x-ray results from a small volume (<1 mm3), bridging four orders of magnitude. Real-time imaging will enable efficient process development and the control of structure evolution to make materials with intended properties; it will also permit the development of experimentally informed, predictive structure and process models. PMID:23779063

  8. An 800-MeV proton radiography facility for dynamic experiments

    SciTech Connect

    King, N.S.P.; Adams, K.; Ables, E.

    1998-12-01

    The capability has been successfully developed at the Los Alamos Nuclear Science Center (LANSCE) to utilize a spatially and temporally prepared 800-MeV proton beam to produce proton radiographs. A series of proton bursts are transmitted through a dynamically varying object and transported, via a unique magnetic lens system, to an image plane. The magnetic lens system permits correcting for the effects of multiple coulomb scattering which would otherwise completely blur the spatially transmitted information at the image plane. The proton radiographs are recorded on either a time integrating film plate or with a recently developed multi-frame electronic imaging camera system. The latter technique permits obtaining a time dependent series of proton radiographs with time intervals (modulo 358 ns) up to many microseconds and variable time intervals between images. One electronically shuttered, intensified, CCD camera is required per image. These cameras can detect single protons interacting with a scintillating fiber optic array in the image plane but also have a dynamic range which permits recording radiographs with better than 5% statistics for observation of detailed density variations in the object. A number of tests have been carried out to characterize the quality of the proton radiography system for absolute mass determination, resolution, and dynamic range. Initial dynamic experiments characterized the temporal and spatial behavior of shock propagation in high explosives with up to six images per experiment. Based on experience with the prototype system, a number of upgrades are being implemented including the anticipated capability for enhanced mass discrimination through differential multiple coulomb scattering radiographs and more images with improved imaging techniques.

  9. Dosimetric uncertainty in prostate cancer proton radiotherapy

    SciTech Connect

    Lin Liyong; Vargas, Carlos; Hsi Wen; Indelicato, Daniel; Slopsema, Roelf; Li Zuofeng; Yeung, Daniel; Horne, Dave; Palta, Jatinder

    2008-11-15

    Purpose: The authors we evaluate the uncertainty in proton therapy dose distribution for prostate cancer due to organ displacement, varying penumbra width of proton beams, and the amount of rectal gas inside the rectum. Methods and Materials: Proton beam treatment plans were generated for ten prostate patients with a minimum dose of 74.1 cobalt gray equivalent (CGE) to the planning target volume (PTV) while 95% of the PTV received 78 CGE. Two lateral or lateral oblique proton beams were used for each plan. The authors we investigated the uncertainty in dose to the rectal wall (RW) and the bladder wall (BW) due to organ displacement by comparing the dose-volume histograms (DVH) calculated with the original or shifted contours. The variation between DVHs was also evaluated for patients with and without rectal gas in the rectum for five patients who had 16 to 47 cc of visible rectal gas in their planning computed tomography (CT) imaging set. The uncertainty due to the varying penumbra width of the delivered protons for different beam setting options on the proton delivery system was also evaluated. Results: For a 5 mm anterior shift, the relative change in the RW volume receiving 70 CGE dose (V{sub 70}) was 37.9% (5.0% absolute change in 13.2% of a mean V{sub 70}). The relative change in the BW volume receiving 70 CGE dose (V{sub 70}) was 20.9% (4.3% absolute change in 20.6% of a mean V{sub 70}) with a 5 mm inferior shift. A 2 mm penumbra difference in beam setting options on the proton delivery system resulted in the relative variations of 6.1% (0.8% absolute change) and 4.4% (0.9% absolute change) in V{sub 70} of RW and BW, respectively. The data show that the organ displacements produce absolute DVH changes that generally shift the entire isodose line while maintaining the same shape. The overall shape of the DVH curve for each organ is determined by the penumbra and the distance of the target in beam's eye view (BEV) from the block edge. The beam setting option producing a 2 mm sharper penumbra at the isocenter can reduce the magnitude of maximal doses to the RW by 2% compared to the alternate option utilizing the same block margin of 7 mm. The dose to 0.1 cc of the femoral head on the distal side of the lateral-posterior oblique beam is increased by 25 CGE for a patient with 25 cc of rectal gas. Conclusion: Variation in the rectal and bladder wall DVHs due to uncertainty in the position of the organs relative to the location of sharp dose falloff gradients should be accounted for when evaluating treatment plans. The proton beam delivery option producing a sharper penumbra reduces maximal doses to the rectal wall. Lateral-posterior oblique beams should be avoided in patients prone to develop a large amount of rectal gas.

  10. Nuclear Emulsion Film Detectors for Proton Radiography:. Design and Test of the First Prototype

    NASA Astrophysics Data System (ADS)

    Braccini, S.; Ereditato, A.; Kreslo, I.; Moser, U.; Pistillo, C.; Studer, S.; Scampoli, P.

    2010-04-01

    Proton therapy is nowadays becoming a wide spread clinical practice in cancer therapy and sophisticated treatment planning systems are routinely used to exploit at best the ballistic properties of charged particles. The information on the quality of the beams and the range of the protons is a key issue for the optimization of the treatment. For this purpose, proton radiography can be used in proton therapy to obtain direct information on the range of the protons, on the average density of the tissues for treatment planning optimization and to perform imaging with negligible dose to the patient. We propose an innovative method based on nuclear emulsion film detectors for proton radiography, a technique in which images are obtained by measuring the position and the residual range of protons passing through the patient's body. Nuclear emulsion films interleaved with tissue equivalent absorbers can be fruitfully used to reconstruct proton tracks with very high precision. The first prototype of a nuclear emulsion based detector has been conceived, constructed and tested with a therapeutic proton beam at PSI. The scanning of the emulsions has been performed at LHEP in Bern, where a fully automated microscopic scanning technology has been developed for the OPERA experiment on neutrino oscillations. After track reconstruction, the first promising experimental results have been obtained by imaging a simple phantom made of PMMA with a step of 1 cm. A second phantom with five 5 5 mm2 section aluminum rods located at different distances and embedded in a PMMA structure has been also imaged. Further investigations are in progress to improve the resolution and to image more sophisticated phantoms.

  11. Proton diffusion along biological membranes

    NASA Astrophysics Data System (ADS)

    Medvedev, E. S.; Stuchebrukhov, A. A.

    2011-06-01

    Biological surfaces are known to be capable of retaining protons and facilitating their lateral diffusion. Since the surface dynamically exchanges protons with the bulk, the proton movement from a source to a target at the surface acquires a complicated pattern of coupled surface and bulk (2D + 3D) diffusion of which the main feature is that the surface acts as a proton-collecting antenna enhancing the proton flux from the bulk. A phenomenological model of this process is reviewed and its applications to recent experiments on lipid bilayers and small unilaminar vesicles are discussed. The model (i) introduces the important notions of the fast and slow regimes of proton exchange between the surface and the bulk, (ii) permits evaluation of the antenna radius and amplification coefficient in both regimes, (iii) explains the observed macroscopically large distances (in the micrometer range; Antonenko and Pohl 1998 FEBS Lett. 429 197) that the proton can travel along lipid membranes embedded into pure aqueous solutions, and (iv) predicts the dependence of the steady-state proton flux and the kinetics of the non-stationary diffusion upon the buffer concentration in buffered solutions. The surface diffusion coefficient for small unilaminar vesicles is calculated from experimental data (Sandn et al 2010 Proc. Natl Acad. Sci. USA 107 4129) to be 1 10 - 5 cm2 s - 1. The dependence of the shape of the kinetic curves representing protonation/deprotonation of a lipid-bound pH-sensitive dye attached to a planar bilayer lipid membrane upon the buffer concentration (Serowy et al 2003 Biophys. J. 84 1031) and the effect of changing the membrane composition (Antonenko and Pohl 2008 Eur. Biophys. J. 37 865) are explained.

  12. RHIC Polarized proton operation

    SciTech Connect

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above injection, the polarized hydrogen jet target runs for every fill with both beams. Based on the known analyzing power, there is very little polarization loss between injection and 100 GeV. An alternative way is to measure the asymmetry at 100 GeV followed by ramping up to 250 GeV and back down to 100 GeV and then to measure the asymmetry again at 100 GeV. If the asymmetry after the down ramp is similar to the measurement before the up ramp, polarization was also preserved during the ramp to 250 GeV. The analyzing power at storage energy can then be extracted from the asymmetries measured at 100 GeV and 250 GeV. The tune and orbit feedbacks are essential for the down ramp to be possible. The polarized proton operation is still going on. We will push bunch intensity higher until reaching the beam-beam limit. The even higher intensity will have to wait for the electron lenses to compensate the beam-beam effect. To understand the details of spin dynamics in RHIC with two snakes, spin simulation with the real magnet fields have been developed recently. The study will provide guidance for possible polarization loss schemes. Further polarization gain will requires a polarized source upgrade; more careful setup jump quads in the AGS to get full benefit; and control emittance in the whole accelerator chain.

  13. Where is the proton's spin

    SciTech Connect

    Close, F.E.

    1988-01-01

    There has been much recent excitement arising from the claim by the EMC collaboration that none of the proton's spin is carried by quarks. There are many textbooks, including those written by some members of this audience, which assert that the proton's spin is carried by quarks. I will review the history of deep inelastic scattering of polarized leptons from polarized protons, culminating in this most recent dramatic claim. I will show that, for the last decade, data have appeared consistent with predictions of the quark model and highlight what the new and potentially exciting data are. I will conclude with suggestions for the future. 33 refs.

  14. Eta Meson Production in Proton-Proton and Nuclear Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank

    2008-01-01

    Total cross sections for eta meson production in proton - proton collisions are calculated. The eta meson is mainly produced via decay of the excited nucleon resonance at 1535 MeV. A scalar quantum field theory is used to calculate cross sections, which also include resonance decay. Comparison between theory and experiment is problematic near threshold when resonance decay is not included. When the decay is included, the comparison between theory and experiment is much better.

  15. Proton Auroral Emissions without Electron Auroral Emissions in Long-lasting Complex Substorms

    NASA Astrophysics Data System (ADS)

    Bryant, C. R.; Murphree, J. S.; Mende, S.

    2008-12-01

    The SI-12 and WIC FUV instruments aboard the IMAGE satellite provide a unique ability to compare LBH and proton auroral emissions. The auroral power allows for the examination of the relationship of proton and electron emissions. In the past, measurements in the LBH band have been used to identify substorms. There are, however, cases where there is significant proton auroral emission while there is little to no electron emission in the LBH band. During intense, long-lasting complex substorms it is possible that while the WIC images show a decreasing intensity and entry into a more recovered state. At the same time, images from the SI-12 camera show increased intensities and possibly further substorms seen only in the proton emissions. An example of this can be seen in the events of November 15, 2001 from 1700-2200 UT. An investigation of this event will be presented and possible explanations of these events will be put forth.

  16. Jet energy measurement with the ATLAS detector in proton-proton collisions at ?{s}=7 TeV

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B. S.; Adams, D. L.; Addy, T. N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; kesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Akiyama, A.; Aktas, A.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alviggi, M. G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V. V.; Amorim, A.; Amors, G.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Archambault, J. P.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; sman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Backhaus, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimares da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, D.; Bartsch, V.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H. S.; Beare, B.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Beck, G. A.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benekos, N.; Benhammou, Y.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M. I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bser, S.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bona, M.; Bondarenko, V. G.; Bondioli, M.; Boonekamp, M.; Boorman, G.; Booth, C. N.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozhko, N. I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brodbeck, T. J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N. J.; Buchholz, P.; Buckingham, R. M.; Buckley, A. G.; Buda, S. I.; Budagov, I. A.; Budick, B.; Bscher, V.; Bugge, L.; Buira-Clark, D.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C. P.; Butin, F.; Butler, B.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Buttinger, W.; Caballero, J.; Cabrera Urbn, S.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L. P.; Caloi, R.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carrillo Montoya, G. D.; Carter, A. A.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A. M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N. F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Cattani, G.; Caughron, S.; Cauz, D.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cetin, S. A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapleau, B.; Chapman, J. D.; Chapman, J. W.; Chareyre, E.; Charlton, D. G.; Chavda, V.; Chavez Barajas, C. A.; Cheatham, S.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V. F.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Cheung, S. L.; Chevalier, L.; Chiefari, G.; Chikovani, L.; Childers, J. T.; Chilingarov, A.; Chiodini, G.; Chizhov, M. V.; Choudalakis, G.; Chouridou, S.; Christidi, I. A.; Christov, A.; Chromek-Burckhart, D.; Chu, M. L.; Chudoba, J.; Ciapetti, G.; Ciba, K.; Ciftci, A. K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M. D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, P. J.; Cleland, W.; Clemens, J. C.; Clement, B.; Clement, C.; Clifft, R. W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Cogan, J. G.; Coggeshall, J.; Cogneras, E.; Cojocaru, C. D.; Colas, J.; Colijn, A. P.; Collard, C.; Collins, N. J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Conde Muio, P.; Coniavitis, E.; Conidi, M. C.; Consonni, M.; Consorti, V.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Copic, K.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Costin, T.; Ct, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B. 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J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Villa, M.; Villani, E. G.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinek, E.; Vinogradov, V. B.; Virchaux, M.; Virzi, J.; Vitells, O.; Viti, M.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vladoiu, D.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, G.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A. P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T. T.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vujicic, M.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wakabayashi, J.; Walbersloh, J.; Walch, S.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, J. C.; Wang, R.; Wang, S. M.; Warburton, A.; Ward, C. P.; Warsinsky, M.; Wastie, R.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, A. T.; Waugh, B. M.; Weber, J.; Weber, M.; Weber, M. S.; Weber, P.; Weidberg, A. R.; Weigell, P.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P. S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Wessels, M.; Weydert, C.; Whalen, K.; Wheeler-Ellis, S. J.; Whitaker, S. P.; White, A.; White, M. J.; White, S.; Whitehead, S. R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wijeratne, P. A.; Wildauer, A.; Wildt, M. A.; Wilhelm, I.; Wilkens, H. G.; Will, J. Z.; Williams, E.; Williams, H. H.; Willis, W.; Willocq, S.; Wilson, J. A.; Wilson, M. G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M. W.; Wolters, H.; Wong, W. C.; Wooden, G.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wraight, K.; Wright, C.; Wright, M.; Wright, D.; Wrona, B.; Wu, S. L.; Wu, X.; Wu, Y.; Wulf, E.; Wunstorf, R.; Wynne, B. M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yacoob, S.; Yamada, M.; Yamaguchi, H.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamanaka, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U. K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, Y.; Yasu, Y.; Ybeles Smit, G. V.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V. G.; Zaidan, R.; Zaitsev, A. M.; Zajacova, Z.; Zalite, Yo. K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zeitnitz, C.; Zeller, M.; Zeman, M.; Zemla, A.; Zendler, C.; Zenin, O.; eni, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi della Porta, G.; Zhan, Z.; Zhang, D.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhang, Q.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Zinonos, Z.; Ziolkowski, M.; Zitoun, R.; ivkovi?, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zutshi, V.; Zwalinski, L.

    2013-03-01

    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of sqrt{s}=7 TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti- k t algorithm with distance parameters R=0.4 or R=0.6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta p T?20 GeV and pseudorapidities | ?|<4.5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2.5 % in the central calorimeter region (| ?|<0.8) for jets with 60? p T<800 GeV, and is maximally 14 % for p T<30 GeV in the most forward region 3.2?| ?|<4.5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon p T, the sum of the transverse momenta of tracks associated to the jet, or a system of low- p T jets recoiling against a high- p T jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high- p T jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined.

  17. Wolfenstein Polarization Observables for the Reactions Proton-Proton --> Proton-Positive Pion Nucleon and Proton - --> Proton-Proton Pion at 800MEV and 650MEV Beam Energies.

    NASA Astrophysics Data System (ADS)

    Xu, Shen-Wu.

    The first measurements of the Wolfenstein polarization parameters D_{NN}, D _{SOmega}, and D _{LOmega}, the induced polarization parameter P and analyzing power A for the reactions vec PP to vec Ppi^+N and vec PP to vec PPpi ^0 at 800 Mev and 650MeV are reported. The experiment was carried out in the external proton beam area of the Clinton P. Anderson Meson Physics Facility (LAMPF), Los Alamos National Laboratory. The 800MeV and 650MeV polarized protein beam was directed onto a liquid -hydrogen target. Three proton beam polarization directions were used: longitudinal (L), sideways (S) in the scattering plane, and normal (N) to the scattering plane. Scattered protons were analyzed in momentum in the dipole-magnet spectrometer. Two orthogonal polarization components of scattered protons were detected with the polarimeter located directly behind the dipole magnet. The measurements were made with the spectrometer spectrometer-polarimeter placed at three central angles, 8.1^circ , 15.2^circ, and 22.0 ^circ, and the conjugate charged particle detectors covered the regions of 20^ circ to 50^circ, and 90^circ to 140 ^circ, corresponding geometrically to Delta production from ~5^circ to ~50^circ in the center-of-mass system. Comparisons are made to results from the model of Dubach, Kloet, and Silbar.

  18. Energy distribution of proton microbeam transmitted through two flat plates

    NASA Astrophysics Data System (ADS)

    Nagy, G. U. L.; Rajta, I.; Bereczky, R. J.; Tőkési, K.

    2015-07-01

    The transmission of 1 MeV proton microbeam passing between two parallel flat plates was investigated. Three different materials were used in our experiments. As insulators we used Polytetrafluoroethylene and borosilicate glass plates and glass with gold layer on the surface as conductor. The surface of the plates was parallel to the beam axis and one of the plates was moved towards the beam. The energy distribution and the deflection of the transmitted beam were measured as the function of the sample distance relative to the beam. We found systematic differences between the behaviour of the metallic and insulator samples. The proton microbeam suffered significant deflection towards the sample surface due to the image acceleration when using conductor material. In case of the glass and Polytetrafluoroethylene plates the beam was deflected into the opposite direction, and the incident protons did not suffer significant energy loss, which is the consequence of the guiding effect.

  19. Proton radiotherapy: some perspectives

    SciTech Connect

    Kirn, T.F.

    1988-02-12

    A news article highlighting the use of protons in radiotherapy is presented. Development of stereotaxic radiosurgery is the result of contributions from physicists, radiologists, and neurosurgeons, says Jacob Fabrikant, MD, head of the Arteriovenous Malformation Program at the University of California's Lawrence Berkeley laboratory. It also appears to have been the product of Harvard University (Boston) and University of California (Berkeley) cooperation. Robert R. Wilson, PhD, now a professor emeritus at Cornell University, Ithaca, NY, is credited with proposing the medical use of charged particles. Wilson, a physicist, says that the idea occurred to him while he was at Berkeley in the mid-1940's, designing the cyclotron to be built at Harvard. Although he was aware of their work, he does not remember discussing it with Robert Stone, MD, or John Lawrence, MD, who only a few years earlier at Berkeley had begun the initial medical experiments with neutrons. Wilson says that it simply occurred to him that in certain instances charged particles had two advantages over x-rays.

  20. Proton-Coupled Electron Transfer

    SciTech Connect

    Weinberg, Dave; Gagliardi, Christopher J.; Hull, Jonathan F; Murphy, Christine Fecenko; Kent, Caleb A.; Westlake, Brittany C.; Paul, Amit; Ess, Daniel H; McCafferty, Dewey Granville; Meyer, Thomas J

    2012-07-11

    Proton-Coupled Electron Transfer (PCET) describes reactions in which there is a change in both electron and proton content between reactants and products. It originates from the influence of changes in electron content on acid-base properties and provides a molecular-level basis for energy transduction between proton transfer and electron transfer. Coupled electron-proton transfer or EPT is defined as an elementary step in which electrons and protons transfer from different orbitals on the donor to different orbitals on the acceptor. There is (usually) a clear distinction between EPT and H-atom transfer (HAT) or hydride transfer, in which the transferring electrons and proton come from the same bond. Hybrid mechanisms exist in which the elementary steps are different for the reaction partners. EPT pathways such as PhO•/PhOH exchange have much in common with HAT pathways in that electronic coupling is significant, comparable to the reorganization energy with H{sub DA} ~ λ. Multiple-Site Electron-Proton Transfer (MS-EPT) is an elementary step in which an electron-proton donor transfers electrons and protons to different acceptors, or an electron-proton acceptor accepts electrons and protons from different donors. It exploits the long-range nature of electron transfer while providing for the short-range nature of proton transfer. A variety of EPT pathways exist, creating a taxonomy based on what is transferred, e.g., 1e-/2H+ MS-EPT. PCET achieves “redox potential leveling” between sequential couples and the buildup of multiple redox equivalents, which is of importance in multielectron catalysis. There are many examples of PCET and pH-dependent redox behavior in metal complexes, in organic and biological molecules, in excited states, and on surfaces. Changes in pH can be used to induce electron transfer through films and over long distances in molecules. Changes in pH, induced by local electron transfer, create pH gradients and a driving force for long-range proton transfer in Photosysem II and through other biological membranes. In EPT, simultaneous transfer of electrons and protons occurs on time scales short compared to the periods of coupled vibrations and solvent modes. A theory for EPT has been developed which rationalizes rate constants and activation barriers, includes temperature- and driving force (ΔG)-dependences implicitly, and explains kinetic isotope effects. The distance-dependence of EPT is dominated by the short-range nature of proton transfer, with electron transfer being far less demanding.Changes in external pH do not affect an EPT elementary step. Solvent molecules or buffer components can act as proton donor acceptors, but individual H2O molecules are neither good bases (pKa(H3O+) = -1.74) nor good acids (pKa(H2O) = 15.7). There are many examples of mechanisms in chemistry, in biology, on surfaces, and in the gas phase which utilize EPT. PCET and EPT play critical roles in the oxygen evolving complex (OEC) of Photosystem II and other biological reactions by decreasing driving force and avoiding high-energy intermediates.

  1. Source characterization and modeling development for monoenergetic-proton radiography experiments on OMEGA

    SciTech Connect

    Manuel, M. J.-E.; Zylstra, A. B.; Rinderknecht, H. G.; Casey, D. T.; Rosenberg, M. J.; Sinenian, N.; Li, C. K.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.

    2012-06-15

    A monoenergetic proton source has been characterized and a modeling tool developed for proton radiography experiments at the OMEGA [T. R. Boehly et al., Opt. Comm. 133, 495 (1997)] laser facility. Multiple diagnostics were fielded to measure global isotropy levels in proton fluence and images of the proton source itself provided information on local uniformity relevant to proton radiography experiments. Global fluence uniformity was assessed by multiple yield diagnostics and deviations were calculated to be {approx}16% and {approx}26% of the mean for DD and D{sup 3}He fusion protons, respectively. From individual fluence images, it was found that the angular frequencies of Greater-Than-Or-Equivalent-To 50 rad{sup -1} contributed less than a few percent to local nonuniformity levels. A model was constructed using the Geant4 [S. Agostinelli et al., Nuc. Inst. Meth. A 506, 250 (2003)] framework to simulate proton radiography experiments. The simulation implements realistic source parameters and various target geometries. The model was benchmarked with the radiographs of cold-matter targets to within experimental accuracy. To validate the use of this code, the cold-matter approximation for the scattering of fusion protons in plasma is discussed using a typical laser-foil experiment as an example case. It is shown that an analytic cold-matter approximation is accurate to within Less-Than-Or-Equivalent-To 10% of the analytic plasma model in the example scenario.

  2. Source characterization and modeling development for monoenergetic-proton radiography experiments on OMEGA

    NASA Astrophysics Data System (ADS)

    Manuel, M. J.-E.; Zylstra, A. B.; Rinderknecht, H. G.; Casey, D. T.; Rosenberg, M. J.; Sinenian, N.; Li, C. K.; Frenje, J. A.; Sguin, F. H.; Petrasso, R. D.

    2012-06-01

    A monoenergetic proton source has been characterized and a modeling tool developed for proton radiography experiments at the OMEGA [T. R. Boehly et al., Opt. Comm. 133, 495 (1997)], 10.1016/S0030-4018(96)00325-2 laser facility. Multiple diagnostics were fielded to measure global isotropy levels in proton fluence and images of the proton source itself provided information on local uniformity relevant to proton radiography experiments. Global fluence uniformity was assessed by multiple yield diagnostics and deviations were calculated to be 16% and 26% of the mean for DD and D3He fusion protons, respectively. From individual fluence images, it was found that the angular frequencies of ?50 rad-1 contributed less than a few percent to local nonuniformity levels. A model was constructed using the Geant4 [S. Agostinelli et al., Nuc. Inst. Meth. A 506, 250 (2003)], 10.1016/S0168-9002(03)01368-8 framework to simulate proton radiography experiments. The simulation implements realistic source parameters and various target geometries. The model was benchmarked with the radiographs of cold-matter targets to within experimental accuracy. To validate the use of this code, the cold-matter approximation for the scattering of fusion protons in plasma is discussed using a typical laser-foil experiment as an example case. It is shown that an analytic cold-matter approximation is accurate to within ?10% of the analytic plasma model in the example scenario.

  3. Proton acceleration experiments with Z-Petawatt.

    SciTech Connect

    Arefiev, A.; Schaumann, G.; Deppert, O.; Rambo, Patrick K.; Roth, M.; Geissel, Matthias; Schwarz, Jens; Sefkow, Adam B.; Atherton, Briggs W.; Kimmel, Mark W.; Schollmeier, Marius; Breizman, B.

    2010-08-01

    The outline of this presentation: (1) Proton acceleration with high-power lasers - Target Normal Sheath Acceleration concept; (2) Proton acceleration with mass-reduced targets - Breaking the 60 MeV threshold; (3) Proton beam divergence control - Novel focusing target geometry; and (4) New experimental capability development - Proton radiography on Z.

  4. Parametric Model for Astrophysical Proton-Proton Interactions and Applications

    SciTech Connect

    Karlsson, Niklas; ,

    2008-01-29

    Observations of gamma-rays have been made from celestial sources such as active galaxies, gamma-ray bursts and supernova remnants as well as the Galactic ridge. The study of gamma rays can provide information about production mechanisms and cosmic-ray acceleration. In the high-energy regime, one of the dominant mechanisms for gamma-ray production is the decay of neutral pions produced in interactions of ultra-relativistic cosmic-ray nuclei and interstellar matter. Presented here is a parametric model for calculations of inclusive cross sections and transverse momentum distributions for secondary particles--gamma rays, e{sup {+-}}, {nu}{sub e}, {bar {nu}}{sub e}, {nu}{sub {mu}} and {bar {nu}}{sub {mu}}--produced in proton-proton interactions. This parametric model is derived on the proton-proton interaction model proposed by Kamae et al.; it includes the diffraction dissociation process, Feynman-scaling violation and the logarithmically rising inelastic proton-proton cross section. To improve fidelity to experimental data for lower energies, two baryon resonance excitation processes were added; one representing the {Delta}(1232) and the other multiple resonances with masses around 1600 MeV/c{sup 2}. The model predicts the power-law spectral index for all secondary particle to be about 0.05 lower in absolute value than that of the incident proton and their inclusive cross sections to be larger than those predicted by previous models based on the Feynman-scaling hypothesis. The applications of the presented model in astrophysics are plentiful. It has been implemented into the Galprop code to calculate the contribution due to pion decays in the Galactic plane. The model has also been used to estimate the cosmic-ray flux in the Large Magellanic Cloud based on HI, CO and gamma-ray observations. The transverse momentum distributions enable calculations when the proton distribution is anisotropic. It is shown that the gamma-ray spectrum and flux due to a pencil beam of protons varies drastically with viewing angle. A fanned proton jet with a Gaussian intensity profile impinging on surrounding material is given as a more realistic example. As the observer is moved off the jet axis, the peak of the spectrum is moved to lower energies.

  5. Voltage-gated proton channels.

    PubMed

    Decoursey, Thomas E

    2012-04-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely, the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance approximately 10(3) times smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ?pH, and potent inhibition by Zn(2+) (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B-lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H(+) for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  6. Proton driver power supply system

    SciTech Connect

    C. Jach and D. Wolff

    2002-06-03

    This paper describes magnet power supply system for a proposed Proton Driver at Fermilab. The magnet power supply system consists of resonant dipole/quadrupole power supply system, quadrupole tracking, dipole correction (horizontal and vertical) and sextupole power supply systems. This paper also describes preliminary design of the power distribution system supplying 13.8 kV power to all proton Driver electrical systems.

  7. Voltage-gated Proton Channels

    PubMed Central

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ?pH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  8. High intensity protons in RHIC

    SciTech Connect

    Montag, C.; Ahrens, L.; Blaskiewicz, M.; Brennan, J. M.; Drees, K. A.; Fischer, W.; Huang, H.; Minty, M.; Robert-Demolaize, G.; Thieberger, P.; Yip, K.

    2012-01-05

    During the 2012 summer shutdown a pair of electron lenses will be installed in RHIC, allowing the beam-beam parameter to be increased by roughly 50 percent. To realize the corresponding luminosity increase bunch intensities have to be increased by 50 percent, to 2.5 {center_dot} 10{sup 11} protons per bunch. We list the various RHIC subsystems that are most affected by this increase, and propose beam studies to ensure their readiness. The proton luminosity in RHIC is presently limited by the beam-beam effect. To overcome this limitation, electron lenses will be installed in IR10. With the help of these devices, the headon beam-beam kick experienced during proton-proton collisions will be partially compensated, allowing for a larger beam-beam tuneshift at these collision points, and therefore increasing the luminosity. This will be accomplished by increasing the proton bunch intensity from the presently achieved 1.65 {center_dot} 10{sup 11} protons per bunch in 109 bunches per beam to 2.5 {center_dot} 10{sup 11}, thus roughly doubling the luminosity. In a further upgrade we aim for bunch intensities up to 3 {center_dot} 10{sup 11} protons per bunch. With RHIC originally being designed for a bunch intensity of 1 {center_dot} 10{sup 11} protons per bunch in 56 bunches, this six-fold increase in the total beam intensity by far exceeds the design parameters of the machine, and therefore potentially of its subsystems. In this note, we present a list of major subsystems that are of potential concern regarding this intensity upgrade, show their demonstrated performance at present intensities, and propose measures and beam experiments to study their readiness for the projected future intensities.

  9. Proton beam monitor chamber calibration

    NASA Astrophysics Data System (ADS)

    Gom, C.; Lorentini, S.; Meer, D.; Safai, S.

    2014-09-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differencesof the order of 3%were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depthi.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambersrather than cylindrical chambersfor the reference dosimetry of pseudo-monoenergetic proton beams.

  10. Recent Solar-Proton Fluxes

    NASA Technical Reports Server (NTRS)

    Reedy, R. C.

    2005-01-01

    The event-integrated fluences of energetic solar protons up to 2004 at the Earth have been determined and compared to previous data. The current solar cycle has been very active, and very large fluxes of solar protons have been observed that have had serious effects in the solar system and will have produced many radionuclides in the surfaces of meteorites. Such huge events are not expected again until about 2008 or 2009.

  11. In Vivo Proton Beam Range Verification Using Spine MRI Changes

    SciTech Connect

    Gensheimer, Michael F.; Yock, Torunn I.; Liebsch, Norbert J.; Sharp, Gregory C.; Paganetti, Harald; Madan, Neel; Grant, P. Ellen; Bortfeld, Thomas

    2010-09-01

    Purpose: In proton therapy, uncertainty in the location of the distal dose edge can lead to cautious treatment plans that reduce the dosimetric advantage of protons. After radiation exposure, vertebral bone marrow undergoes fatty replacement that is visible on magnetic resonance imaging (MRI). This presents an exciting opportunity to observe radiation dose distribution in vivo. We used quantitative spine MRI changes to precisely detect the distal dose edge in proton radiation patients. Methods and Materials: We registered follow-up T1-weighted MRI images to planning computed tomography scans from 10 patients who received proton spine irradiation. A radiation dose-MRI signal intensity curve was created using the lateral beam penumbra in the sacrum. This curve was then used to measure range errors in the lumbar spine. Results: In the lateral penumbra, there was an increase in signal intensity with higher dose throughout the full range of 0-37.5 Gy (RBE). In the distal fall-off region, the beam sometimes appeared to penetrate farther than planned. The mean overshoot in 10 patients was 1.9 mm (95% confidence interval, 0.8-3.1 mm), on the order of the uncertainties inherent to our range verification method. Conclusions: We have demonstrated in vivo proton range verification using posttreatment spine MRI changes. Our analysis suggests the presence of a systematic overshoot of a few millimeters in some proton spine treatments, but the range error does not exceed the uncertainty incorporated into the treatment planning margin. It may be possible to extend our technique to MRI sequences that show early bone marrow changes, enabling adaptive treatment modification.

  12. Technical Note: Spatial resolution of proton tomography: Impact of air gap between patient and detector

    SciTech Connect

    Schneider, Uwe; Besserer, Juergen; Hartmann, Matthias

    2012-02-15

    Purpose: Proton radiography and tomography were investigated since the early 1970s because of its low radiation dose, high density resolution, and ability to image directly proton stopping power. However, spatial resolution is still a limiting factor. In this note, preliminary results of the impact of an air gap between detector system and patient on spatial resolution are presented. Methods: Spatial resolution of proton radiography and tomography is governed by multiple Coulomb scattering (MCS) of the protons in the patient. In this note, the authors employ Monte Carlo simulations of protons traversing a 20 cm thick water box. Entrance and exit proton coordinate measurements were simulated for improved spatial resolution. The simulations were performed with and without a 5 cm air gap in front of and behind the patient. Loss of spatial resolution due to the air gap was studied for protons with different initial angular confusion. Results: It was found that spatial resolution is significantly deteriorated when a 5 cm air gap between the position sensitive detector and the patient is included. For a perfect parallel beam spatial resolution worsens by about 40%. Spatial resolution is getting worse with increasing angular confusion and can reach 80%. Conclusions: When proton radiographies are produced by measuring the entrance and exit coordinates of the protons in front of and behind the patient the air gap between the detector and the patient can significantly deteriorate the spatial resolution of the system by up to 80%. An alternative would be to measure in addition to the coordinates also the exit and entrance angles of each proton. In principle, using the air gap size and proton angle, images can be reconstructed with the same spatial resolution than without air gap.

  13. Note: Proton microbeam formation with continuously variable kinetic energy using a compact system for three-dimensional proton beam writing

    SciTech Connect

    Ohkubo, T. Ishii, Y.

    2015-03-15

    A compact focused gaseous ion beam system has been developed to form proton microbeams of a few hundreds of keV with a penetration depth of micrometer range in 3-dimensional proton beam writing. Proton microbeams with kinetic energies of 100-140 keV were experimentally formed on the same point at a constant ratio of the kinetic energy of the object side to that of the image side. The experimental results indicate that the beam diameters were measured to be almost constant at approximately 6 ?m at the same point with the kinetic energy range. These characteristics of the system were experimentally and numerically demonstrated to be maintained as long as the ratio was constant.

  14. Generation of proton aurora by magnetosonic waves

    PubMed Central

    Xiao, Fuliang; Zong, Qiugang; Wang, Yongfu; He, Zhaoguo; Su, Zhenpeng; Yang, Chang; Zhou, Qinghua

    2014-01-01

    Earth's proton aurora occurs over a broad MLT region and is produced by the precipitation of low-energy (2–10 keV) plasmasheet protons. Proton precipitation can alter chemical compositions of the atmosphere, linking solar activity with global climate variability. Previous studies proposed that electromagnetic ion cyclotron waves can resonate with protons, producing proton scattering precipitation. A long-outstanding question still remains whether there is another mechanism responsible for the proton aurora. Here, by performing satellite data analysis and diffusion equation calculations, we show that fast magnetosonic waves can produce trapped proton scattering that yields proton aurora. This provides a new insight into the mechanism of proton aurora. Furthermore, a ray-tracing study demonstrates that magnetosonic wave propagates over a broad MLT region, consistent with the global distribution of proton aurora. PMID:24898626

  15. Generation of proton aurora by magnetosonic waves.

    PubMed

    Xiao, Fuliang; Zong, Qiugang; Wang, Yongfu; He, Zhaoguo; Su, Zhenpeng; Yang, Chang; Zhou, Qinghua

    2014-01-01

    Earth's proton aurora occurs over a broad MLT region and is produced by the precipitation of low-energy (2-10?keV) plasmasheet protons. Proton precipitation can alter chemical compositions of the atmosphere, linking solar activity with global climate variability. Previous studies proposed that electromagnetic ion cyclotron waves can resonate with protons, producing proton scattering precipitation. A long-outstanding question still remains whether there is another mechanism responsible for the proton aurora. Here, by performing satellite data analysis and diffusion equation calculations, we show that fast magnetosonic waves can produce trapped proton scattering that yields proton aurora. This provides a new insight into the mechanism of proton aurora. Furthermore, a ray-tracing study demonstrates that magnetosonic wave propagates over a broad MLT region, consistent with the global distribution of proton aurora. PMID:24898626

  16. Relaxation of Protons by Radicals in Rotationally Immobilized Proteins

    PubMed Central

    Korb, Jean-Pierre; Diakova, Galina; Goddard, Yanina; Bryant, Robert G.

    2007-01-01

    Proton spin-lattice relaxation by paramagnetic centers may be dramatically enhanced if the paramagnetic center is rotationally immobilized in the magnetic field. The details of the relaxation mechanism are different from those appropriate to solutions of paramagnetic relaxation agents. We report here large enhancements in the proton spin-lattice relaxation rate constants associated with organic radicals when the radical system is rigidly connected with a rotationally immobilized macromolecular matrix such as a dry protein or a cross-linked protein gel. The paramagnetic contribution to the protein-proton population is direct and distributed internally among the protein protons by efficient spin diffusion. In the case of a cross-linked-protein gel, the paramagnetic effects are carried to the water spins indirectly by chemical exchange mechanisms involving water molecule exchange with rare long-lived water molecule binding sites on the immobilized protein and proton exchange. The dramatic increase in the efficiency of spin relaxation by organic radicals compared with metal systems at low magnetic field strengths results because the electron relaxation time of the radical is orders of magnitude larger than that for metal systems. This gain in relaxation efficiency provides completely new opportunities for the design of spin-lattice relaxation based contrast agents in magnetic imaging and also provides new ways to examine intramolecular protein dynamics. PMID:17336112

  17. The physics of Cerenkov light production during proton therapy.

    PubMed

    Helo, Y; Kacperek, A; Rosenberg, I; Royle, G; Gibson, A P

    2014-12-01

    There is increasing interest in using Cerenkov emissions for quality assurance and in vivo dosimetry in photon and electron therapy. Here, we investigate the production of Cerenkov light during proton therapy and its potential applications in proton therapy. A primary proton beam does not have sufficient energy to generate Cerenkov emissions directly, but we have demonstrated two mechanisms by which such emissions may occur indirectly: (1) a fast component from fast electrons liberated by prompt gamma (99.13%) and neutron (0.87%) emission; and (2) a slow component from the decay of radioactive positron emitters. The fast component is linear with dose and doserate but carries little spatial information; the slow component is non-linear but may be localised. The properties of the two types of emission are explored using Monte Carlo modelling in GEANT4 with some experimental verification. We propose that Cerenkov emissions could contribute to the visual sensation reported by some patients undergoing proton therapy of the eye and we discuss the feasibility of some potential applications of Cerenkov imaging in proton therapy. PMID:25365447

  18. Heteronuclear proton assisted recoupling

    NASA Astrophysics Data System (ADS)

    De Pape, Gal; Lewandowski, Jzef R.; Loquet, Antoine; Eddy, Matt; Megy, Simon; Bckmann, Anja; Griffin, Robert G.

    2011-03-01

    We describe a theoretical framework for understanding the heteronuclear version of the third spin assisted recoupling polarization transfer mechanism and demonstrate its potential for detecting long-distance intramolecular and intermolecular 15N-13C contacts in biomolecular systems. The pulse sequence, proton assisted insensitive nuclei cross polarization (PAIN-CP) relies on a cross term between 1H-15N and 1H-13C dipolar couplings to mediate zero- and/or double-quantum 15N-13C recoupling. In particular, using average Hamiltonian theory we derive effective Hamiltonians for PAIN-CP and show that the transfer is mediated by trilinear terms of the form NC?Hz (ZQ) or NCHz (DQ) depending on the rf field strengths employed. We use analytical and numerical simulations to explain the structure of the PAIN-CP optimization maps and to delineate the appropriate matching conditions. We also detail the dependence of the PAIN-CP polarization transfer with respect to local molecular geometry and explain the observed reduction in dipolar truncation. In addition, we demonstrate the utility of PAIN-CP in structural studies with 15N-13C spectra of two uniformly 13C,15N labeled model microcrystalline proteinsGB1, a 56 amino acid peptide, and Crh, a 85 amino acid domain swapped dimer (MW = 2 10.4 kDa). The spectra acquired at high magic angle spinning frequencies (?r/2? > 20 kHz) and magnetic fields (?0H/2? = 700-900 MHz) using moderate rf fields, yield multiple long-distance intramonomer and intermonomer 15N-13C contacts. We use these distance restraints, in combination with the available x-ray structure as a homology model, to perform a calculation of the monomer subunit of the Crh protein.

  19. Can we Observe "stimulated" Proton Beta Decay?

    NASA Astrophysics Data System (ADS)

    Borcea, Catalin

    2015-06-01

    The possibility of observing proton beta decay in a scattering system proton- (high Z) nucleus is examined from a simplified perspective. The proton is supposed to move on a Rutherford trajectory and the extra proton energy necessary to compensate the mass difference with respect to decay products can be provided on the account of potential energy of the proton in the electrostatic field of the nucleus.

  20. Computing Proton Dose to Irregularly Moving Targets

    PubMed Central

    Phillips, Justin; Gueorguiev, Gueorgui; Shackleford, James A.; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C.

    2014-01-01

    Purpose While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, and 95.7% with 3 cm drift in the phantom (2 mm, 2%), and 90.8% (3 mm, 3%)for the patient data. Conclusions We have demonstrated a method for accurately reproducing proton dose to an irregularly moving target from a single CT image. We believe this algorithm could prove a useful tool to study the dosimetric impact of baseline shifts either before or during treatment. PMID:25029239

  1. Computing proton dose to irregularly moving targets

    NASA Astrophysics Data System (ADS)

    Phillips, Justin; Gueorguiev, Gueorgui; Shackleford, James A.; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C.

    2014-08-01

    Purpose: While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods: The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results: A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, 95.7% with 3 cm drift in the phantom (2 mm, 2%), and 90.8% (3 mm, 3%)for the patient data. Conclusions: We have demonstrated a method for accurately reproducing proton dose to an irregularly moving target from a single CT image. We believe this algorithm could prove a useful tool to study the dosimetric impact of baseline shifts either before or during treatment.

  2. Comparison of short-lived medical isotopes activation by laser thin target induced protons and conventional cyclotron proton beams

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Dudnikova, Galina; Liu, Tung-Chang; Papadopoulos, Dennis; Sagdeev, Roald; Su, J. J.; UMD MicroPET Team

    2014-10-01

    Production diagnostic or therapeutic nuclear medicines are either by nuclear reactors or by ion accelerators. In general, diagnostic nuclear radioisotopes have a very short half-life varying from tens of minutes for PET tracers and few hours for SPECT tracers. Thus supplies of PET and SPECT radiotracers are limited by regional production facilities. For example 18F-fluorodeoxyglucose (FDG) is the most desired tracer for positron emission tomography because its 110 minutes half-life is sufficient long for transport from production facilities to nearby users. From nuclear activation to completing image taking must be done within 4 hours. Decentralized production of diagnostic radioisotopes will be idea to make high specific activity radiotracers available to researches and clinicians. 11 C, 13 N, 15 O and 18 F can be produced in the energy range from 10-20 MeV by protons. Protons of energies up to tens of MeV generated by intense laser interacting with hydrogen containing targets have been demonstrated by many groups in the past decade. We use 2D PIC code for proton acceleration, Geant4 Monte Carlo code for nuclei activation to compare the yields and specific activities of short-lived isotopes produced by cyclotron proton beams and laser driven protons.

  3. Proton-proton Scattering Above 3 GeV/c

    SciTech Connect

    A. Sibirtsev, J. Haidenbauer, H.-W. Hammer S. Krewald ,Ulf-G. Meissner

    2010-01-01

    A large set of data on proton-proton differential cross sections, analyzing powers and the double-polarization parameter A{sub NN} is analyzed employing the Regge formalism. We find that the data available at proton beam momenta from 3 GeV/c to 50 GeV/c exhibit features that are very well in line with the general characteristics of Regge phenomenology and can be described with a model that includes the {rho}, {omega}, f{sub 2}, and a{sub 2} trajectories and single-Pomeron exchange. Additional data, specifically for spin-dependent observables at forward angles, would be very helpful for testing and refining our Regge model.

  4. IMAGES, IMAGES, IMAGES

    SciTech Connect

    Marcus, A.

    1980-07-01

    The role of images of information (charts, diagrams, maps, and symbols) for effective presentation of facts and concepts is expanding dramatically because of advances in computer graphics technology, increasingly hetero-lingual, hetero-cultural world target populations of information providers, the urgent need to convey more efficiently vast amounts of information, the broadening population of (non-expert) computer users, the decrease of available time for reading texts and for decision making, and the general level of literacy. A coalition of visual performance experts, human engineering specialists, computer scientists, and graphic designers/artists is required to resolve human factors aspects of images of information. The need for, nature of, and benefits of interdisciplinary effort are discussed. The results of an interdisciplinary collaboration are demonstrated in a product for visualizing complex information about global energy interdependence. An invited panel will respond to the presentation.

  5. Large-scale proton radiography with micrometer spatial resolution using femtosecond petawatt laser system

    NASA Astrophysics Data System (ADS)

    Wang, W. P.; Shen, B. F.; Zhang, H.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Yu, L. H.; Chu, Y. X.; Li, Y. Y.; Xu, T. J.; Zhang, H.; Zhai, S. H.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.

    2015-10-01

    An image of dragonfly with many details is obtained by the fundamental property of the high-energy proton source on a femtosecond petawatt laser system. Equal imaging of the dragonfly and high spatial resolution on the micrometer scale are simultaneously obtained. The head, wing, leg, tail, and even the internal tissue structures are clearly mapped in detail by the proton beam. Experiments show that image blurring caused by multiple Coulomb scattering can be reduced to a certain extent and the spatial resolution can be increased by attaching the dragonfly to the RCFs, which is consistent with theoretical assumptions.

  6. Measurement of the Wolfenstein parameters for proton-proton and proton-neutron scattering at 500 MeV

    SciTech Connect

    Marshall, J.A.

    1984-07-01

    Using liquid hydrogen and liquid deuterium targets respectively, forward angle (ten degrees to sixty degrees in the center of Mass) free proton-proton and quasielastic proton-proton and proton-neutron triple scattering data at 500 MeV have been obtained using the high resolution spectrometer at the Los Alamos Meson Physics Facility. The data are in reasonable agreement with recent predictions from phase shift analyses, indicating that the proton-nucleon scattering amplitudes are fairly well determined at 500 MeV. 32 references.

  7. The Structure of the Proton

    DOE R&D Accomplishments Database

    Chambers, E. E.; Hofstadter, R.

    1956-04-01

    The structure and size of the proton have been studied by means of the methods of high-energy electron scattering. The elastic scattering of electrons from protons in polyethylene has been investigated at the following energies in the laboratory system: 200, 300, 400, 500, 550 Mev. The range of laboratory angles examined has been 30 degrees to 135 degrees. At the largest angles and the highest energy, the cross section for scattering shows a deviation below that expected from a point proton by a factor of about nine. The magnitude and variation with angle of the deviations determine a structure factor for the proton, and thereby determine the size and shape of the charge and magnetic-moment distributions within the proton. An interpretation, consistent at all energies and angles and agreeing with earlier results from this laboratory, fixes the rms radius at 0.77 {plus or minus} 0.10 x 10{sup -13} cm for each of the charge and moment distributions. The shape of the density function is not far from a Gaussian with rms radius 0.70 x 10{sup -13} cm or an exponential with rms radius 0.80 x 10 {sup -13} cm. An equivalent interpretation of the experiments would ascribe the apparent size to a breakdown of the Coulomb law and the conventional theory of electromagnetism.

  8. Intramolecular proton transfer in channelrhodopsins.

    PubMed

    Sineshchekov, Oleg A; Govorunova, Elena G; Wang, Jihong; Li, Hai; Spudich, John L

    2013-02-19

    Channelrhodopsins serve as photoreceptors that control the motility behavior of green flagellate algae and act as light-gated ion channels when heterologously expressed in animal cells. Here, we report direct measurements of proton transfer from the retinylidene Schiff base in several channelrhodopsin variants expressed in HEK293 cells. A fast outward-directed current precedes the passive channel current that has the opposite direction at physiological holding potentials. This rapid charge movement occurs on the timescale of the M intermediate formation in microbial rhodopsins, including that for channelrhodopsin from Chlamydomonas augustae and its mutants, reported in this study. Mutant analysis showed that the glutamate residue corresponding to Asp(85) in bacteriorhodopsin acts as the primary acceptor of the Schiff-base proton in low-efficiency channelrhodopsins. Another photoactive-site residue corresponding to Asp(212) in bacteriorhodopsin serves as an alternative proton acceptor and plays a more important role in channel opening than the primary acceptor. In more efficient channelrhodopsins from Chlamydomonas reinhardtii, Mesostigma viride, and Platymonas (Tetraselmis) subcordiformis, the fast current was apparently absent. The inverse correlation of the outward proton transfer and channel activity is consistent with channel function evolving in channelrhodopsins at the expense of their capacity for active proton transport. PMID:23442959

  9. Petrophysical applications of NMR imaging

    SciTech Connect

    Rothwell, W.P.; Vinegar, H.J.

    1985-12-01

    A system for obtaining high-resolution NMR images of oil field cores is described. Separate proton density and T/sub 2/ relaxation images are obtained to distinguish spatial variations of fluid-filled porosity and the physical nature of the pores. Results are presented for typical sandstones.

  10. Heavy quark photoproduction in proton-proton collisions

    SciTech Connect

    Goncalves, V.P.; Machado, M.V.T.

    2005-01-01

    We calculate the photoproduction of heavy quarks in proton-proton collisions at RHIC, Tevatron, and CERN LHC energies, where the photon reaches energies larger than those accessible at DESY-HERA. The integrated cross section and the rapidity distributions for open charm and bottom production are computed employing sound high energy QCD formalisms. For the linear perturbative QCD approaches we consider both the usual collinear factorization and the k{sub perpendicular}-factorization formalisms, whereas for the nonlinear QCD (saturation) calculations one considers the Golec-Biernat-Wuesthoff and the Iancu-Itakura-Munier parametrizations for the dipole cross section within the color dipole picture.

  11. Measuring the strong electrostatic and magnetic fields with proton radiography for ultra-high intensity laser channeling on fast ignitiona)

    NASA Astrophysics Data System (ADS)

    Uematsu, Y.; Ivancic, S.; Iwawaki, T.; Habara, H.; Lei, A. L.; Theobald, W.; Tanaka, K. A.

    2014-11-01

    In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E 1011 V/m and B 108 G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma.

  12. Measuring the strong electrostatic and magnetic fields with proton radiography for ultra-high intensity laser channeling on fast ignition.

    PubMed

    Uematsu, Y; Ivancic, S; Iwawaki, T; Habara, H; Lei, A L; Theobald, W; Tanaka, K A

    2014-11-01

    In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E ∼ 10(11) V/m and B ∼ 10(8) G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma. PMID:25430358

  13. Measuring the strong electrostatic and magnetic fields with proton radiography for ultra-high intensity laser channeling on fast ignition

    SciTech Connect

    Uematsu, Y.; Iwawaki, T.; Habara, H. Tanaka, K. A.; Ivancic, S.; Theobald, W.; Lei, A. L.

    2014-11-15

    In order to investigate the intense laser propagation and channel formation in dense plasma, we conducted an experiment with proton deflectometry on the OMEGA EP Laser facility. The proton image was analyzed by tracing the trajectory of mono-energetic protons, which provides understanding the electric and magnetic fields that were generated around the channel. The estimated field strengths (E ? 10{sup 11} V/m and B ? 10{sup 8} G) agree with the predictions from 2D-Particle-in-cell (PIC) simulations, indicating the feasibility of the proton deflectometry technique for over-critical density plasma.

  14. Optical Emissions from Proton Aurora

    NASA Technical Reports Server (NTRS)

    Lummerzheim, D.; Galand, M.; Kubota, M.

    2003-01-01

    Hydrogen emissions are the signature of proton aurora. The Doppler-shifted hydrogen emission lines can be interpreted in terms of the mean energy of the precipitating protons. A red shifted component of the line profiles observed from the ground indicates upward going hydrogen atoms due to angular redistribution of the precipitation. Secondary electrons from ionization and stripping collisions also contribute to the auroral emissions. Since the energy distribution of these secondaries has a lower mean energy than secondary electrons in electron aurora, the relative brightness of eniission features differs from that in electron aurora. The secondaries contribute little to additional ionization. These differences between proton and electron aurora can lead to misinterpretation when brightness ratios are used to derive ionospheric conductances with parameterizations that are based on electron aurora.

  15. The search for proton decay

    SciTech Connect

    Haines, T.; Kaneyuki, K.; McGrew, C.; Mohapatra, R.; Peterson, E.; Cline, D.B.

    1994-12-31

    The conservation of the quantum number called baryon number, like lepton (or family) number, is an empirical fact even though there are very good reasons to expect otherwise. Experimentalists have been searching for baryon number violating decays of the proton and neutron for decades now without success. Theorists have evolved deep understanding of the relationship between the natural forces in the development of various Grand Unified Theories (GUTs) that nearly universally predict baryon number violating proton decay, or related phenomena like n-{bar n} oscillations. With this in mind, the Proton Decay Working Group reviewed the current experimental and theoretical status of the search for baryon number violation with an eye to the advancement in the next decade.

  16. Polarized proton beams in RHIC

    SciTech Connect

    Zelenski, A.

    2010-10-04

    The polarized beam for RHIC is produced in the optically-pumped polarized H{sup -} ion source and then accelerated in Linac to 200 MeV for strip-injection to Booster and further accelerated 24.3 GeV in AGS for injection in RHIC. In 2009 Run polarized protons was successfully accelerated to 250 GeV beam energy. The beam polarization of about 60% at 100 GeV beam energy and 36-42% at 250 GeV beam energy was measured with the H-jet and p-Carbon CNI polarimeters. The gluon contribution to the proton spin was studied in collisions of longitudinally polarized proton beams at 100 x 100 GeV. At 250 x 250 GeV an intermediate boson W production with the longitudinally polarized beams was studied for the first time.

  17. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    NASA Astrophysics Data System (ADS)

    Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  18. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV.

    PubMed

    Sjue, S K L; Mariam, F G; Merrill, F E; Morris, C L; Saunders, A

    2016-01-01

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets. PMID:26827356

  19. Physiologic and Radiographic Evidence of the Distal Edge of the Proton Beam in Craniospinal Irradiation

    SciTech Connect

    Krejcarek, Stephanie C.; Grant, P. Ellen; Henson, John W.; Tarbell, Nancy J.; Yock, Torunn I. . E-mail: tyock@partners.org

    2007-07-01

    Purpose: Fatty replacement of bone marrow resulting from radiation therapy can be seen on T1-weighted magnetic resonance (MR) images. We evaluated the radiographic appearance of the vertebral bodies in children treated with proton craniospinal irradiation (CSI) to illustrate the distal edge effect of proton radiotherapy. Methods and Materials: The study cohort consisted of 13 adolescents aged 12-18 years who received CSI with proton radiotherapy at Massachusetts General Hospital. Ten of these patients had reached maximal or near-maximal growth. Proton beam radiation for these 10 patients was delivered to the thecal sac and exiting nerve roots only, whereas the remaining 3 patients had a target volume that included the thecal sac, exiting nerve roots, and entire vertebral bodies. Median CSI dose was 27 [range, 23.4-36] cobalt gray equivalent (CGE) given in 1.8-CGE fractions. Magnetic resonance images of the spine were obtained after completion of radiotherapy. Results: Magnetic resonance images of patients who received proton radiotherapy to the thecal sac only demonstrate a sharp demarcation of hyperintense T1-weighted signal in the posterior aspects of the vertebral bodies, consistent with radiation-associated fatty marrow replacement. Magnetic resonance images of the patients prescribed proton radiotherapy to the entire vertebral column had corresponding hyperintense T1-weighted signal involving the entire vertebral bodies. Conclusion: The sharp delineation of radiation-associated fatty marrow replacement in the vertebral bodies demonstrates the rapid decrease in energy at the edge of the proton beam. This provides evidence for a sharp fall-off in radiation dose and supports the premise that proton radiotherapy spares normal tissues unnecessary irradiation.

  20. Physiologic and Radiographic Evidence of the Distal Edge of the Proton Beam in Craniospinal Irradiation

    PubMed Central

    Krejcarek, Stephanie C.; Grant, P. Ellen; Henson, John. W.; Tarbell, Nancy J.; Yock, Torunn I.

    2007-01-01

    Purpose Fatty replacement of bone marrow resulting from radiation therapy can be seen on T1-weighted magnetic resonance (MR) images. We evaluated the radiographic appearance of the vertebral bodies in children treated with proton craniospinal irradiation (CSI) to illustrate the distal edge effect of proton radiotherapy. Methods The study cohort consists of 13 adolescents between the ages of 1218 who received CSI with proton radiotherapy at Massachusetts General Hospital. Ten of these patients had reached maximal or near-maximal growth. Proton beam radiation for these ten patients was delivered to the thecal sac and exiting nerve roots only, whereas the remaining three patients had a target volume that included the thecal sac, exiting nerve roots and entire vertebral bodies. Median CSI dose was 27 [range 23.436] Cobalt Gray Equivalents (CGE) given in 1.8 CGE fractions. MR images of the spine were obtained after completion of radiotherapy. Results MR images of patients who received proton radiotherapy to the thecal sac only demonstrate a sharp demarcation of hyperintense T1-weighted signal in the posterior aspects of the vertebral bodies, consistent with radiation-associated fatty marrow replacement. MR images of the patients prescribed proton radiotherapy to the entire vertebral column had corresponding hyperintense T1-weighted signal involving the entire vertebral bodies. Conclusion The sharp delineation of radiation-associated fatty marrow replacement in the vertebral bodies demonstrates the rapid decrease in energy at the edge of the proton beam. This provides evidence for a sharp fall-off in radiation dose and supports the premise that proton radiotherapy spares normal tissues unnecessary irradiation. PMID:17449195

  1. Proton aurora and substorm intensifications

    NASA Technical Reports Server (NTRS)

    Samson, J. C.; Xu, B.; Lyons, L. R.; Newell, P. T.; Creutzberg, F.

    1993-01-01

    Ground based measurements from the CANOPUS array of meridian scanning photometers and precipitating ion and electron data from the DMSP F9 satellite show that the electron arc which brightens to initiate substorm intensifications is formed within a region of intense proton precipitation that is well equatorward (approximately four to six degrees) of the nightside open-closed field line boundary. The precipitating protons are from a population that is energized via earthward convection from the magnetotail into the dipolar region of the magnetosphere and may play an important role in the formation of the electron arcs leading to substorm intensifications on dipole-like field lines.

  2. Charge transport along proton wires.

    PubMed

    Karahka, Markus Leopold; Kreuzer, Hans Jürgen

    2013-12-01

    Using density functional theory we look at the quantum mechanics of charge transport along water wires both with free ends and donor/acceptor terminated. With the intermediate geometries in the DFT iterations we can follow the charge transfer mechanism and also construct the energy landscape explicitly. It shows activation barriers when a proton is transferred from one water molecule to the next. This, together with snapshots of intermediate geometries, leads to a justification and further elucidation of the Grotthuss mechanism and the Bjerrum effect. The charge transfer times and the conductivity of the proton wire are obtained in agreement with experimental results. PMID:24706126

  3. Modeling of Proton-Induced CCD Degradation in the Chandra X-Ray Observatory

    NASA Technical Reports Server (NTRS)

    Lo, D. H.; Srour, J. R.

    2003-01-01

    Modeling results are presented for proton-induced degradation of charge-coupled devices (CCDs) used in the Advanced CCD Imaging Spectrometer instrument on the Chandra X-Ray Observatory. A methodology is described that provides insights regarding degradation mechanism and on-orbit performance for front-illuminated and back-illuminated CCDs Proton-induced changes in charge transfer inefficiency are modeled. The observed amount of on-orbit degradation can be accounted for using a proton spectrum at the CCD location that is reduced in magnitude by a factor of approx. 1E5 compared to the spectrum incident on the spacecraft.

  4. Search for proton radioactivity in65As,69Br and77Y

    NASA Astrophysics Data System (ADS)

    Hourani, E.; Azaiez, F.; Dessagne, Ph.; Elayi, A.; Fortier, S.; Gales, S.; Maison, J. M.; Massolo, P.; Miehe, Ch.; Richard, A.

    1989-09-01

    A search for proton radioactivity in65As,69Br and77Y, produced as residues of fusion reactions, was carried out at the Orsay Tandem accelerator. The residues were collected at the image point of the spectrometer Soleno and implanted into the gaseous medium of an ionization chamber which was also used to detect the radioactivity protons. No such protons have been observed in the energy range of 250 600 keV and in the half-life interval of 10 ?s-100 ms, within a production cross section sensitivity of 1 ?b.

  5. Shockwave and detonation studies at ITEP-TWAC proton radiography facility

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Sergey; Dudin, Sergey; Lavrov, Vladimir; Nikolaev, Dmitry; Mintsev, Victor; Shilkin, Nikolay; Ternovoi, Vladimir; Utkin, Alexander; Yakushev, Vladislav; Yuriev, Denis; Fortov, Vladimir; Golubev, Alexander; Kantsyrev, Alexey; Shestov, Lev; Smirnov, Gennady; Turtikov, Vladimir; Sharkov, Boris; Burtsev, Vasily; Zavialov, Nikolay; Kartanov, Sergey; Mikhailov, Anatoly; Rudnev, Alexey; Tatsenko, Mikhail; Zhernokletov, Mikhail

    2012-03-01

    In recent years studies of shock and detonation wave phenomena at extreme dynamic conditions were performed at proton radiography facility developed at the 800 MeV proton beam line of ITEP Terawatt Accelerator (ITEP-TWAC). The facility provides a multi-frame imaging capability at 50 ?m spatial and 70 ns temporal resolution. The results of latest studies conducted there are presented, including explosion and detonation of pressed and emulsion high explosives, shock-induced dense non-ideal plasma of argon and xenon and shock loading of non-uniform metal surfaces. New compact explosive generators developed specifically for a use at proton radiography facilities are also presented.

  6. Vision 20/20: Proton therapy

    SciTech Connect

    Smith, Alfred R.

    2009-02-15

    The first patients were treated with proton beams in 1955 at the Lawrence Berkeley Laboratory in California. In 1970, proton beams began to be used in research facilities to treat cancer patients using fractionated treatment regimens. It was not until 1990 that proton treatments were carried out in hospital-based facilities using technology and techniques that were comparable to those for modern photon therapy. Clinical data strongly support the conclusion that proton therapy is superior to conventional radiation therapy in a number of disease sites. Treatment planning studies have shown that proton dose distributions are superior to those for photons in a wide range of disease sites indicating that additional clinical gains can be achieved if these treatment plans can be reliably delivered to patients. Optimum proton dose distributions can be achieved with intensity modulated protons (IMPT), but very few patients have received this advanced form of treatment. It is anticipated widespread implementation of IMPT would provide additional improvements in clinical outcomes. Advances in the last decade have led to an increased interest in proton therapy. Currently, proton therapy is undergoing transitions that will move it into the mainstream of cancer treatment. For example, proton therapy is now reimbursed, there has been rapid development in proton therapy technology, and many new options are available for equipment, facility configuration, and financing. During the next decade, new developments will increase the efficiency and accuracy of proton therapy and enhance our ability to verify treatment planning calculations and perform quality assurance for proton therapy delivery. With the implementation of new multi-institution clinical studies and the routine availability of IMPT, it may be possible, within the next decade, to quantify the clinical gains obtained from optimized proton therapy. During this same period several new proton therapy facilities will be built and the cost of proton therapy is expected to decrease, making proton therapy routinely available to a larger population of cancer patients.

  7. Sub-oval proton aurora spots: Mapping relatively to the plasmapause

    NASA Astrophysics Data System (ADS)

    Yahnin, A. G.; Yahnina, T. A.; Frey, H.; Pierrard, V.

    2013-07-01

    Sub-oval proton auroras discovered by the IMAGE spacecraft correlate with EMIC waves (geomagnetic pulsations of the Pc1 range). This means that a common source of the waves and proton precipitation is the ion-cyclotron (IC) instability developing in the vicinity of the equatorial plane. Different forms of the proton auroras reflect different regimes of the IC instability and different conditions in the near-Earth equatorial magnetosphere. To understand what are the conditions for the generation of the sub-oval proton aurora one may map the aurora onto the equatorial plane and compare the projection with some important magnetospheric boundaries. In this report we compare the projection of so-called proton aurora spots with the location of the plasmapause. The latter is determined by the plasmapause formation model based on the quasi-interchange instability mechanism. The comparison shows that often the proton aurora spot source is located in the vicinity of the plasmapause or in the cold plasma gradient inside the plasmapause. In some events, the proton aurora spots map well outside the plasmapause. We assume that in the latter case the IC instability develops when westward drifting energetic protons interact with the cold plasma that was earlier detached from the plasmasphere.

  8. The donut and dynamic polarization effects in proton channeling through carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Borka, D.; Mowbray, D. J.; Mikovi?, Z. L.; Petrovi?, S.; Nekovi?, N.

    2010-04-01

    We investigate the angular and spatial distributions of protons with an energy of 0.223 MeV after channeling them through an (11, 9) single-wall carbon nanotube of 0.2 ?m length. The proton incident angle is varied between 0 and 10 mrad, being close to the critical angle for channeling. We show that, as the proton incident angle increases and approaches the critical angle for channeling, a ring-like structure is developed in the angular distributionthe donut effect. We demonstrate that it is the rainbow effect. If the proton incident angle is between zero and half of the critical angle for channeling, the image force affects considerably the number and positions of the maxima of the angular and spatial distributions. However, if the proton incident angle is close to the critical angle for channeling, its influence on the angular and spatial distributions is considerably decreased. We demonstrate that an increase of the proton incident angle can lead to a significant rearrangement of the propagating protons within the nanotube. This effect may be used to locate atomic impurities in nanotubes as well as for creating nanosized proton beams to be used in materials science, biology and medicine.

  9. COMPARISON OF PARTICLE-TRACKING FEATURES IN GEANT4 AND MCNPX CODES FOR APPLICATIONS IN MAPPING OF PROTON RANGE UNCERTAINTY.

    PubMed

    Bednarz, Bryan; Chen, Gty; Paganetti, Harald; Han, Bin; Ding, Aiping; Xu, X George

    2011-07-01

    The accuracy of proton therapy is partially limited by uncertainties that result from changing pathological conditions in the patient such as tumor motion and shrinkage. These uncertainties can be minimized with the help of a time-resolved range telescope. Monte Carlo methods can help improve the performance of range telescopes by tracking proton interactions on a particle-by-particle basis thus broadening our understanding on the behavior of protons within the patient and the detector. This paper compared the proton multiple coulomb scattering algorithms in the Monte Carlo codes MCNPX and Geant4 to well-established scattering theories. We focus only on beam energies associated with proton imaging. Despite slight discrepancies between scattering algorithms, both codes appear to be capable of providing useful particle-tracking information for applications such as the proton range telescope. PMID:22389531

  10. Long-range azimuthal correlations in protonproton and protonnucleus collisions from the incoherent scattering of partons

    SciTech Connect

    Ma, Guo -Liang; Bzdak, Adam

    2014-11-04

    In this study, we show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest partonparton cross-section of ? = 1.5 3 mb, naturally explains the long-range two-particle azimuthal correlation as observed in protonproton and protonnucleus collisions at the Large Hadron Collider.

  11. Fetal imaging by nuclear magnetic resonance: a study in goats: work in progress

    SciTech Connect

    Foster, M.A.; Knight, C.H.; Rimmington, J.E.; Mallard, J.R.

    1983-10-01

    Nuclear magnetic resonance proton imaging was used to obtain images of goat fetuses in utero. The long T1 relaxation time of amniotic fluid makes it appear black on proton density images when examined using the Aberdeen imager, and so allows very good discrimination of the position and structure of the fetus. Some fetal internal tissues can be seen on T1 images. These findings suggest that NMR imaging has great potential in pregnancy studies.

  12. Fire Under Fire: Proton Probabilities at Perihelion

    NASA Technical Reports Server (NTRS)

    Kiplinger, A. L.; Tsurutani, B. T.

    1996-01-01

    This paper computes the probabilities that the near-Sun flyby mission, Fire, might be bombarded by high energy protons from solar-activity related proton acceleration lying beneath Fire's perihelion altitude of three solar radii.

  13. Determining the mechanism of cusp proton aurora

    PubMed Central

    Xiao, Fuliang; Zong, Qiugang; Su, Zhenpeng; Yang, Chang; He, Zhaoguo; Wang, Yongfu; Gao, Zhonglei

    2013-01-01

    Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2–10 keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora. PMID:23575366

  14. Polarized protons and parity violating asymmetries

    SciTech Connect

    Trueman, T.L.

    1984-01-01

    The potential for utilizing parity violating effects, associated with polarized protons, to study the standard model, proton structure, and new physics at the SPS Collider is summarized. 24 references.

  15. Determining the mechanism of cusp proton aurora.

    PubMed

    Xiao, Fuliang; Zong, Qiugang; Su, Zhenpeng; Yang, Chang; He, Zhaoguo; Wang, Yongfu; Gao, Zhonglei

    2013-01-01

    Earth's cusp proton aurora occurs near the prenoon and is primarily produced by the precipitation of solar energetic (2-10?keV) protons. Cusp auroral precipitation provides a direct source of energy for the high-latitude dayside upper atmosphere, contributing to chemical composition change and global climate variability. Previous studies have indicated that magnetic reconnection allows solar energetic protons to cross the magnetopause and enter the cusp region, producing cusp auroral precipitation. However, energetic protons are easily trapped in the cusp region due to a minimum magnetic field existing there. Hence, the mechanism of cusp proton aurora has remained a significant challenge for tens of years. Based on the satellite data and calculations of diffusion equation, we demonstrate that EMIC waves can yield the trapped proton scattering that causes cusp proton aurora. This moves forward a step toward identifying the generation mechanism of cusp proton aurora. PMID:23575366

  16. Alpha proton x ray spectrometer

    NASA Technical Reports Server (NTRS)

    Rieder, Rudi; Waeke, H.; Economou, T.

    1994-01-01

    Mars Pathfinder will carry an alpha-proton x ray spectrometer (APX) for the determination of the elemental chemical composition of Martian rocks and soils. The instrument will measure the concentration of all major and some minor elements, including C, N, and O at levels above typically 1 percent.

  17. Invariant Spin in the Proton

    SciTech Connect

    Thomas, Anthony W.

    2008-10-13

    We discuss recent theoretical progress in understanding the distribution of spin and orbital angular momentum in the proton. Particular attention is devoted to the effect of QCD evolution and to the distinction between 'chiral' and 'invariant' spin. This is particularly significant with respect to the possible presence of polarized strange quarks.

  18. Resist materials for proton micromachining

    NASA Astrophysics Data System (ADS)

    van Kan, J. A.; Sanchez, J. L.; Xu, B.; Osipowicz, T.; Watt, F.

    1999-10-01

    The production of high aspect ratio microstructures is a potential growth area. The combination of deep X-ray lithography with electroforming and micromolding (i.e. LIGA) is one of the main techniques used to produce 3D microstructures. The new technique of proton micromachining employs focused MeV protons in a direct write process which is complementary to LIGA, e.g. micromachining with 2 MeV protons results in microstructures with a height of 63 ?m and lateral sub-micrometer resolution in PMMA resist. The aim of this paper is to investigate the capabilities of proton micromachining as a lithographic technique. This involves the study of different types of resists. The dose distribution of high molecular weight PMMA is compared with three other types of resist: First the positive photo resist AZ P4620 will be discussed and then PMGI SF 23, which can be used as a deep UV, e-beam or X-ray resist. Finally SU-8, a new deep UV negative type of chemically amplified resist will be discussed. All these polymers are applied using the spin coating technique at thicknesses of between 1 and 36 ?m

  19. Low-Energy Proton Testing Methodology

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.; Marshall, Paul W.; Heidel, David F.; Schwank, James R.; Shaneyfelt, Marty R.; Xapsos, M.A.; Ladbury, Raymond L.; LaBel, Kenneth A.; Berg, Melanie; Kim, Hak S.; Phan, Anthony; Friendlich, M.R.; Rodbell, Kenneth P.; Hakey, Mark C.; Dodd, Paul E.; Reed, Robert A.; Weller, Robert A.; Mendenhall, Marcus H.; Sierawski, B.D.

    2009-01-01

    Use of low-energy protons and high-energy light ions is becoming necessary to investigate current-generation SEU thresholds. Systematic errors can dominate measurements made with low-energy protons. Range and energy straggling contribute to systematic error. Low-energy proton testing is not a step-and-repeat process. Low-energy protons and high-energy light ions can be used to measure SEU cross section of single sensitive features; important for simulation.

  20. Proton pump inhibitor-induced hypomagnesemic hypoparathyroidism

    PubMed Central

    Swaminathan, Krishnan

    2015-01-01

    Proton pump inhibitors are the one of the most widely used drugs in the world. Hypomagnesemic hypoparathyroidism has been reported with different proton pump inhibitors with prolonged oral use. We report the first reported case of possible such effect with intravenous preparation of proton pump inhibitor. This case report raises awareness among physicians worldwide of this often unknown association, as life-threatening cardiac and neuromuscular complications can arise with unrecognized hypocalcemia and hypomagnesemia with proton pump inhibitors. PMID:26069375

  1. The size of the proton.

    PubMed

    Pohl, Randolf; Antognini, Aldo; Nez, Franois; Amaro, Fernando D; Biraben, Franois; Cardoso, Joo M R; Covita, Daniel S; Dax, Andreas; Dhawan, Satish; Fernandes, Luis M P; Giesen, Adolf; Graf, Thomas; Hnsch, Theodor W; Indelicato, Paul; Julien, Lucile; Kao, Cheng-Yang; Knowles, Paul; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, Jos A M; Ludhova, Livia; Monteiro, Cristina M B; Mulhauser, Franoise; Nebel, Tobias; Rabinowitz, Paul; Dos Santos, Joaquim M F; Schaller, Lukas A; Schuhmann, Karsten; Schwob, Catherine; Taqqu, David; Veloso, Joo F C A; Kottmann, Franz

    2010-07-01

    The proton is the primary building block of the visible Universe, but many of its properties-such as its charge radius and its anomalous magnetic moment-are not well understood. The root-mean-square charge radius, r(p), has been determined with an accuracy of 2 per cent (at best) by electron-proton scattering experiments. The present most accurate value of r(p) (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants. This value is based mainly on precision spectroscopy of atomic hydrogen and calculations of bound-state quantum electrodynamics (QED; refs 8, 9). The accuracy of r(p) as deduced from electron-proton scattering limits the testing of bound-state QED in atomic hydrogen as well as the determination of the Rydberg constant (currently the most accurately measured fundamental physical constant). An attractive means to improve the accuracy in the measurement of r(p) is provided by muonic hydrogen (a proton orbited by a negative muon); its much smaller Bohr radius compared to ordinary atomic hydrogen causes enhancement of effects related to the finite size of the proton. In particular, the Lamb shift (the energy difference between the 2S(1/2) and 2P(1/2) states) is affected by as much as 2 per cent. Here we use pulsed laser spectroscopy to measure a muonic Lamb shift of 49,881.88(76) GHz. On the basis of present calculations of fine and hyperfine splittings and QED terms, we find r(p) = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm. Our result implies that either the Rydberg constant has to be shifted by -110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient. PMID:20613837

  2. Solar proton fluences at GEO

    NASA Astrophysics Data System (ADS)

    Ikeda, Masahiko; Goka, Tateo; Kazama, Yoichi

    NWIP: 14N532 "Observed Proton Fluences over long duration at GEO and Guideline for selection of confidence level in statistical model of Solar Proton Fluences" was approved. 1. Background:Solar energetic protons (SEP) degrade solar panels of GEO spacecrafts. Today, mission lives of many GEO satellites are longer than 11 years. At the end of its mission, solar panel of such satellite outputs more power than estimated. This suggests that today's statistical SEP models predict SEP harsher than natural environment. 2. Purpose:To estimate "proper" proton fluences for the solar cell degradation over long duration at GEO is our goal. This project is for engineering community, and its benefits are adapted to satellite manufactures of the world. 3.Outline of estimation (1) Prepare time-series observed proton daily fluences at GEO. (2) Calculate n-year fluences by integrating daily fluences by shifting the integrating window day-by-day. (3) Select maximum of set of the integrated fluences as the estimated fluences for the n-year mission period. (4) Compare the estimated fluences with confidence level of statistical SEP models. Drs Goka and Kazama already orally presented this method, and their paper is in press. 4.Status at ISO WG4 (1) Project participants of 14N532 are France, Japan, Russia, Ukraine, USA and China. (2) WD is under study. (3) Next target date is 1/23/2009 for CD. To meet the request by world satellite manufactures, namely practical guideline for confidence level, NWIP will be registered as the TS quickly. And actual result will be accumulated then promote to IS, if beneficial.

  3. Fast neutron production from lithium converters and laser driven protons

    SciTech Connect

    Storm, M.; Jiang, S.; Wertepny, D.; Orban, C.; Morrison, J.; Willis, C.; McCary, E.; Balencourt, P.; Snyder, J.; Chowdhury, E.; Freeman, R. R.; Akli, K.; Bang, W.; Gaul, E.; Dyer, G.; Ditmire, T.

    2013-05-15

    Experiments to generate neutrons from the {sup 7}Li(p,n){sup 7}Be reaction with 60 J, 180 fs laser pulses have been performed at the Texas Petawatt Laser Facility at the University of Texas at Austin. The protons were accelerated from the rear surface of a thin target membrane using the target-normal-sheath-acceleration mechanism. The neutrons were generated in nuclear reactions caused by the subsequent proton bombardment of a pure lithium foil of natural isotopic abundance. The neutron energy ranged up to 2.9 MeV. The total yield was estimated to be 1.6 10{sup 7} neutrons per steradian. An extreme ultra-violet light camera, used to image the target rear surface, correlated variations in the proton yield and peak energy to target rear surface ablation. Calculations using the hydrodynamics code FLASH indicated that the ablation resulted from a laser pre-pulse of prolonged intensity. The ablation severely limited the proton acceleration and neutron yield.

  4. Proton radiography and fluoroscopy of lung tumors: A Monte Carlo study using patient-specific 4DCT phantoms

    PubMed Central

    Han, Bin; Xu, X. George; Chen, George T. Y.

    2011-01-01

    Purpose: Monte Carlo methods are used to simulate and optimize a time-resolved proton range telescope (TRRT) in localization of intrafractional and interfractional motions of lung tumor and in quantification of proton range variations. Methods: The Monte Carlo N-Particle eXtended (MCNPX) code with a particle tracking feature was employed to evaluate the TRRT performance, especially in visualizing and quantifying proton range variations during respiration. Protons of 230 MeV were tracked one by one as they pass through position detectors, patient 4DCT phantom, and finally scintillator detectors that measured residual ranges. The energy response of the scintillator telescope was investigated. Mass density and elemental composition of tissues were defined for 4DCT data. Results: Proton water equivalent length (WEL) was deduced by a reconstruction algorithm that incorporates linear proton track and lateral spatial discrimination to improve the image quality. 4DCT data for three patients were used to visualize and measure tumor motion and WEL variations. The tumor trajectories extracted from the WEL map were found to be within ?1 mm agreement with direct 4DCT measurement. Quantitative WEL variation studies showed that the proton radiograph is a good representation of WEL changes from entrance to distal of the target. Conclusions:MCNPX simulation results showed that TRRT can accurately track the motion of the tumor and detect the WEL variations. Image quality was optimized by choosing proton energy, testing parameters of image reconstruction algorithm, and comparing to ground truth 4DCT. The future study will demonstrate the feasibility of using the time resolved proton radiography as an imaging tool for proton treatments of lung tumors. PMID:21626923

  5. Proton Radiography: Cross Section Measurements and Detector Development

    SciTech Connect

    Michael J. Longo; H. R. Gustafson: Durga Rajaram; Turgun Nigmanov

    2010-04-16

    Proton radiography has become an important tool for predicting the performance of stockpiled nuclear weapons. Current proton radiography experiments at LANSCE are confined to relatively small targets on the order of centimeters in size because of the low beam energy. LANL scientists have made radiographs with 12 and 24 GeV protons produced by the accelerator at Brookhaven National Laboratory. These energies are in the range required for hydrotest radiography. The design of a facility for hydrotest radiography requires knowledge of the cross sections for producing high-energy particles in the forward direction, which are incorporated into the Monte Carlo simulation used in designing the beam and detectors. There are few existing measurements of neutron production cross sections for proton-nuclei interactions in the 50 GeV range, and almost no data exist for forward neutron production, especially for heavy target nuclei. Thus the data from the MIPP EMCAL and HCAL, for which our group was responsible, are critical to proton radiography. Since neutrons and photons cannot be focused by magnets, they cause a background “fog” on the images. This problem can be minimized by careful design of the focusing system and detectors. The purpose of our research was to measure forward production of neutrons produced by high-energy proton beams striking a variety of targets. The forward-going particles carry most of the energy from a high-energy proton interaction, so these are the most important to proton radiography. This work was carried out in conjunction with the Fermilab E-907 (MIPP) collaboration. Our group was responsible for designing and building the E907 forward neutron and photon calorimeters. With the support of our Stewardship Science Academic Alliances grants, we were able to design, build, and commission the calorimeters on budget and ahead of schedule. The MIPP experiment accumulated a large amount of data in the first run that ended in early 2006. Our group has almost completed the analysis the forward neutron production data. Large dis-crepancies between our neutron production data and Monte Carlo expectations have been found.

  6. Sequence dependent proton conduction in self-assembled peptide nanostructures

    NASA Astrophysics Data System (ADS)

    Lerner Yardeni, Jenny; Amit, Moran; Ashkenasy, Gonen; Ashkenasy, Nurit

    2016-01-01

    The advancement of diverse electrochemistry technologies depends on the development of novel proton conducting polymers. Inspired by the efficacy of proton transport through proteins, we show in this work that self-assembling peptide nanostructures may be a promising alternative for such organic proton conducting materials. We demonstrate that aromatic amino acids, which participate in charge transport in nature, unprecedentedly promote proton conduction under both high and low relative humidity conditions for d,l α-cyclic peptide nanotubes. For dehydrated networks long-range order of the assemblies, induced by the aromatic side chains, is shown to be a dominating factor for promoting conductivity. However, for hydrated networks this order of effect is less significant and conductivity can be improved by the introduction of proton donating carboxylic acid peptide side chains in addition to the aromatic side chains despite the lower order of the assemblies. Based on these observations, a novel cyclic peptide that incorporates non-natural naphthyl side chains was designed. Self-assembled nanotubes of this peptide show greatly improved dehydrated conductivity, while maintaining high conductivity under hydrated conditions. We envision that the demonstrated modularity and versatility of these bio inspired nanostructures will make them extremely attractive building blocks for the fabrication of devices for energy conversion and storage applications, as well as other applications that involve proton transport, whether dry or wet conductivity is desired.The advancement of diverse electrochemistry technologies depends on the development of novel proton conducting polymers. Inspired by the efficacy of proton transport through proteins, we show in this work that self-assembling peptide nanostructures may be a promising alternative for such organic proton conducting materials. We demonstrate that aromatic amino acids, which participate in charge transport in nature, unprecedentedly promote proton conduction under both high and low relative humidity conditions for d,l α-cyclic peptide nanotubes. For dehydrated networks long-range order of the assemblies, induced by the aromatic side chains, is shown to be a dominating factor for promoting conductivity. However, for hydrated networks this order of effect is less significant and conductivity can be improved by the introduction of proton donating carboxylic acid peptide side chains in addition to the aromatic side chains despite the lower order of the assemblies. Based on these observations, a novel cyclic peptide that incorporates non-natural naphthyl side chains was designed. Self-assembled nanotubes of this peptide show greatly improved dehydrated conductivity, while maintaining high conductivity under hydrated conditions. We envision that the demonstrated modularity and versatility of these bio inspired nanostructures will make them extremely attractive building blocks for the fabrication of devices for energy conversion and storage applications, as well as other applications that involve proton transport, whether dry or wet conductivity is desired. Electronic supplementary information (ESI) available: Details of c(K&cmb.b.line;KNaph)4 synthesis, AFM images, additional electrical characterization including conductance vs. electrode distance data, example of transient measurement and additional I-V. See DOI: 10.1039/c5nr06750b

  7. Fast Whole-Brain Three-dimensional Macromolecular Proton Fraction Mapping in Multiple Sclerosis

    PubMed Central

    Bowen, James D.; Samsonov, Alexey; Repovic, Pavle; Mayadev, Angeli; Qian, Peiqing; Gangadharan, Beena; Keogh, Bart P.; Maravilla, Kenneth R.; Jung Henson, Lily K.

    2015-01-01

    Purpose To evaluate the clinical utility of fast whole-brain macromolecular proton fraction (MPFmacromolecular proton fraction) mapping in multiple sclerosis (MSmultiple sclerosis) and compare MPFmacromolecular proton fraction with established quantitative magnetic resonance (MR) imaging measures of tissue damage including magnetization transfer (MTmagnetization transfer) ratio and relaxation rate (R1). Materials and Methods In this institutional review boardapproved and HIPAA-compliant study, 14 healthy control participants, 18 relapsing-remitting MSmultiple sclerosis (RRMSrelaxing-remitting MS) patients, and 12 secondary progressive MSmultiple sclerosis (SPMSsecondary progressive MS) patients provided written informed consent and underwent 3-T MR imaging. Three-dimensional MPFmacromolecular proton fraction maps were reconstructed from MTmagnetization transfer-weighted images and R1 maps by the single-point method. Mean MPFmacromolecular proton fraction, R1, and MTmagnetization transfer ratio in normal-appearing white matter (WMwhite matter), gray matter (GMgray matter), and lesions were compared between subject groups by using analysis of variance. Correlations (Pearson r) between imaging data and clinical scores (Expanded Disability Status Scale [EDSS] and MSmultiple sclerosis Functional Composite [MSFCMS functional composite]) were compared by using Hotelling-Williams test. Results RRMSrelaxing-remitting MS patients had lower WMwhite matter and GMgray matter MPFmacromolecular proton fraction than controls, with percentage decreases of 6.5% (P < .005) and 5.4% (P < .05). MPFmacromolecular proton fraction in SPMSsecondary progressive MS was reduced relative to RRMSrelaxing-remitting MS in WMwhite matter, GMgray matter, and lesions by 6.4% (P < .005), 13.4% (P < .005), and 11.7% (P < .05), respectively. EDSSExpanded Disability Status Scale and MSFCMS functional composite demonstrated strongest correlations with MPFmacromolecular proton fraction in GMgray matter (r = ?0.74 and 0.81; P < .001) followed by WMwhite matter (r = ?0.57 and 0.72; P < .01) and lesions (r = ?0.42 and 0.50; P < .05). R1 and MTmagnetization transfer ratio in all tissues were significantly less correlated with clinical scores than GMgray matter MPFmacromolecular proton fraction (P < .05). Conclusion MPFmacromolecular proton fraction mapping enables quantitative assessment of demyelination in normal-appearing brain tissues and shows primary clinical relevance of GMgray matter damage in MSmultiple sclerosis. MPFmacromolecular proton fraction outperforms MTmagnetization transfer ratio and R1 in detection of MSmultiple sclerosis-related tissue changes. RSNA, 2014 PMID:25208343

  8. Field match verification during combination proton, photon, and electron therapy for oligometastatic inflammatory breast cancer

    SciTech Connect

    Amos, Richard A.; Woodward, Wendy A.

    2012-01-01

    Postmastectomy radiation therapy (PMRT) has been shown in randomized trials to improve overall survival for patients with locally advanced breast cancer. The standard PMRT clinical target volume (CTV) encompasses the chest wall and undissected regional lymphatics. Conformal isodose distributions covering the standard CTV with acceptable dose limits to normal tissue can typically be achieved with a combination of photon and electron fields. Field borders are marked on the patient's skin using a light field projection of each beam and are subsequently used to verify daily field matching clinically. Initial imaging of a patient with oligometastatic inflammatory breast cancer demonstrated direct extension of disease from the involved internal mammary lymph node chain into the anterior mediastinum as the only site of metastatic disease. The patient achieved a pathologic complete response to neoadjuvant chemotherapy and underwent mastectomy. The initial sites of gross disease, including the anterior mediastinal node was included in the CTV for PMRT, and treatment planning demonstrated a clear advantage to the inclusion of proton fields in this case. The absence of a light source on the proton delivery system that accurately projects proton field edges onto the patient's skin posed a significant challenge for daily verification of proton-to-photon and -electron field matching. Proton field-specific radiographic imaging devices were designed and used such that proton field edges could be delineated on the patient's skin and used for daily matching with photon and electron fields. Manufacture of the imaging devices was quick and inexpensive. Weekly verification of proton field alignment with the proton field delineation on the skin demonstrated agreement within 3-mm tolerance. The patient remains with no evidence of disease 18 months after completing radiation. Other patients with similar indications may benefit from multimodality radiation therapy.

  9. Proton Range Uncertainty Due to Bone Cement Injected Into the Vertebra in Radiation Therapy Planning

    SciTech Connect

    Lim, Young Kyung; Hwang, Ui-Jung; Shin, Dongho; Kim, Dong Wook; Kwak, Jungwon; Yoon, Myonggeun; Lee, Doo Hyun; Lee, Se Byeong; Lee, Sang-Yeob; Park, Sung Yong; Pyo, Hong Ryeol

    2011-10-01

    We wanted to evaluate the influence of bone cement on the proton range and to derive a conversion factor predicting the range shift by correcting distorted computed tomography (CT) data as a reference to determine whether the correction is needed. Two CT datasets were obtained with and without a bone cement disk placed in a water phantom. Treatment planning was performed on a set of uncorrected CT images with the bone cement disk, and the verification plan was applied to the same set of CT images with an effective CT number for the bone cement disk. The effective CT number was determined by measuring the actual proton range with the bone cement disk. The effects of CT number, thicknesses, and position of bone cement on the proton range were evaluated in the treatment planning system (TPS) to draw a conversion factor predicting the range shift by correcting the CT number of bone cement. The effective CT number of bone cement was 260 Hounsfield units (HU). The calculated proton range for native CT data was significantly shorter than the measured proton range. However, the calculated range for the corrected CT data with the effective CT number coincided exactly with the measured range. The conversion factor was 209.6 [HU . cm/mm] for bone cement and predicted the range shift by approximately correcting the CT number. We found that the heterogeneity of bone cement could cause incorrect proton ranges in treatment plans using CT images. With an effective CT number of bone cement derived from the proton range and relative stopping power, a more actual proton range could be calculated in the TPS. The conversion factor could predict the necessity for CT data correction with sufficient accuracy.

  10. Protonation of silylenol ether via excited state proton transfer catalysis.

    PubMed

    Das, Anjan; Banerjee, Tanmay; Hanson, Kenneth

    2016-01-14

    We demonstrate the photocatalytic protonation of a silylenol ether using 7-bromo-2-naphthol as an ESPT catalyst with phenol as the sacrificial proton source. Greater than 95% conversion is achieved with 1 mol% catalyst. The reaction cycle is dependent on the significantly increased acidity of the catalyst in the excited state as well as the long lifetime for the triplet excited state of 7-bromo-2-naphthol. The reaction does not occur in the absence of light (367 nm) and can readily be controlled by light intensity modulation. We also demonstrate that a 72% reaction yield can be obtained with unsubstituted naphthol as the catalyst by coupling triplet energy transfer, via a visible light absorbing (445 nm) sensitizer, into the catalytic cycle. These results open the door to an entirely new class of sensitized photocatalytic reactions that harness the excited state acidity of ESPT dyes. PMID:26502917

  11. Near threshold proton-proton fusion in effective field theory

    NASA Astrophysics Data System (ADS)

    Chen, Jiunn-Wei; Liu, C.-P.; Yu, Shen-Hsi

    2013-03-01

    The astrophysical S-factor for proton-proton fusion, S11 (E), is obtained with the nuclear matrix element analytically calculated in pionless effective field theory. To the third order, the zero-energy result S11 (0) and the first energy derivative S11? (0) are found to be (3.99 0.14) 10-25MeV b and S11 (0) (11.3 0.1)MeV-1, respectively; both consistent with the current adopted values. The second energy derivative is also calculated for the first time, and the result S11? (0) =S11 (0) (170 2)MeV-2 contributes at the level of 0.5% to the fusion rate at the solar center, which is smaller than 1% as previously estimated.

  12. Sensitivity and Source of Amine Proton EXchange (APEX) and Amide Proton Transfer (APT) MRI in Cerebral Ischemia

    PubMed Central

    Zong, Xiaopeng; Wang, Ping; Kim, Seong-Gi; Jin, Tao

    2013-01-01

    Purpose Amide proton transfer (APT) and amine-water proton exchange (APEX) can be viable to map pH-decreasing ischemic regions. However, their exact contributions are unclear. Methods We measured APEX- and APT-weighted magnetization transfer ratio asymmetry (denoted as APEXw and APTw), ADC, T2 and T1 images, and localized proton spectra in rats with permanent middle cerebral artery occlusion at 9.4 T. Phantoms and theoretical studies were also performed. Results Within one hour post-occlusion, APEXw and APTw maps showed hyperintensity (3.1% of M0) and hypointensity (?1.8%), respectively, in regions with decreased ADC. Ischemia increased lactate and gamma aminobutyric acid (GABA) concentrations, but decreased glutamate and taurine concentrations. Over time, the APEXw contrast decreased with glutamate, taurine and creatine, while the APTw contrast and lactate level were similar. Phantom and theoretical studies suggest that the source of APEXw signal is mainly from proteins at normal pH, while at decreased pH, GABA and glutamate contributions increase, inducing the positive APEXw contrast in ischemic regions. The APTw contrast is sensitive to lactate concentration and pH, but contaminated from contributions of the faster amine-water proton exchange processes. Conclusion Positive APEXw contrast is more sensitive to ischemia than negative APTw contrast. They may provide complementary tissue metabolic information. PMID:23401310

  13. MRI-Based Computed Tomography Metal Artifact Correction Method for Improving Proton Range Calculation Accuracy

    SciTech Connect

    Park, Peter C.; Schreibmann, Eduard; Roper, Justin; Elder, Eric; Crocker, Ian; Fox, Tim; Zhu, X. Ronald; Dong, Lei; Dhabaan, Anees

    2015-03-15

    Purpose: Computed tomography (CT) artifacts can severely degrade dose calculation accuracy in proton therapy. Prompted by the recently increased popularity of magnetic resonance imaging (MRI) in the radiation therapy clinic, we developed an MRI-based CT artifact correction method for improving the accuracy of proton range calculations. Methods and Materials: The proposed method replaces corrupted CT data by mapping CT Hounsfield units (HU number) from a nearby artifact-free slice, using a coregistered MRI. MRI and CT volumetric images were registered with use of 3-dimensional (3D) deformable image registration (DIR). The registration was fine-tuned on a slice-by-slice basis by using 2D DIR. Based on the intensity of paired MRI pixel values and HU from an artifact-free slice, we performed a comprehensive analysis to predict the correct HU for the corrupted region. For a proof-of-concept validation, metal artifacts were simulated on a reference data set. Proton range was calculated using reference, artifactual, and corrected images to quantify the reduction in proton range error. The correction method was applied to 4 unique clinical cases. Results: The correction method resulted in substantial artifact reduction, both quantitatively and qualitatively. On respective simulated brain and head and neck CT images, the mean error was reduced from 495 and 370 HU to 108 and 92 HU after correction. Correspondingly, the absolute mean proton range errors of 2.4 cm and 1.7 cm were reduced to less than 2 mm in both cases. Conclusions: Our MRI-based CT artifact correction method can improve CT image quality and proton range calculation accuracy for patients with severe CT artifacts.

  14. Proton conduction in biopolymer exopolysaccharide succinoglycan

    SciTech Connect

    Kweon, Jin Jung; Lee, Kyu Won; Kim, Hyojung; Lee, Cheol Eui; Jung, Seunho; Kwon, Chanho

    2014-07-07

    Protonic currents play a vital role in electrical signalling in living systems. It has been suggested that succinoglycan plays a specific role in alfalfa root nodule development, presumably acting as the signaling molecules. In this regard, charge transport and proton dynamics in the biopolymer exopolysaccharide succinoglycan have been studied by means of electrical measurements and nuclear magnetic resonance (NMR) spectroscopy. In particular, a dielectric dispersion in the system has revealed that the electrical conduction is protonic rather electronic. Besides, our laboratory- and rotating-frame {sup 1}H NMR measurements have elucidated the nature of the protonic conduction, activation of the protonic motion being associated with a glass transition.

  15. Excited state of protonated benzene and toluene

    NASA Astrophysics Data System (ADS)

    Esteves-Lpez, Natalia; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2015-08-01

    We present photo-fragmentation electronic spectra of the simplest protonated aromatic molecules, protonated benzene and toluene, recorded under medium resolution conditions and compared with the photo-fragmentation spectrum of protonated pyridine. Despite the resolution and cold temperature achieved in the experiment, the electronic spectra of protonated benzene and toluene are structure-less, thus intrinsically broadened. This is in agreement with the large geometrical changes and the fast dynamic toward internal conversion predicted by ab initio calculations for protonated benzene [Rode et al., J. Phys. Chem. A 113, 5865-5873 (2009)].

  16. Compact proton spectrometers for measurements of shock

    SciTech Connect

    Mackinnon, A; Zylstra, A; Frenje, J A; Seguin, F H; Rosenberg, M J; Rinderknecht, H G; Johnson, M G; Casey, D T; Sinenian, N; Manuel, M; Waugh, C J; Sio, H W; Li, C K; Petrasso, R D; Friedrich, S; Knittel, K; Bionta, R; McKernan, M; Callahan, D; Collins, G; Dewald, E; Doeppner, T; Edwards, M J; Glenzer, S H; Hicks, D; Landen, O L; London, R; Meezan, N B

    2012-05-02

    The compact Wedge Range Filter (WRF) proton spectrometer was developed for OMEGA and transferred to the National Ignition Facility (NIF) as a National Ignition Campaign (NIC) diagnostic. The WRF measures the spectrum of protons from D-{sup 3}He reactions in tuning-campaign implosions containing D and {sup 3}He gas; in this work we report on the first proton spectroscopy measurement on the NIF using WRFs. The energy downshift of the 14.7-MeV proton is directly related to the total {rho}R through the plasma stopping power. Additionally, the shock proton yield is measured, which is a metric of the final merged shock strength.

  17. Proton hydrates as soft ion/ion proton transfer reagents for multiply deprotonated biomolecules

    NASA Astrophysics Data System (ADS)

    Bowers, Jeremiah J.; Hodges, Brittany D. M.; Saad, Ola M.; Leary, Julie A.; McLuckey, Scott A.

    2008-10-01

    Ion/ion proton transfer from protonated strong gaseous bases such as pyridine and 1,8-bis(dimethylamino)naphthalene (i.e., the proton sponge), to multiply charged anions derived from a sulfated pentasaccharide drug, Arixtra(TM), gives rise to extensive fragmentation of the oligosaccharide. This drug serves as a model for sulfated glycosaminoglycans, an important class of polymers in glycobiology. The extent of fragmentation appears to correlate with the proton affinity of the molecule used to transfer the proton, which in turn correlates with the reaction exothermicity. Consistent with tandem mass spectrometry results, anions with sodium counter-ions are more stable with respect to fragmentation under ion/ion proton transfer conditions than ions of the same charge state with protons counter-ions. Proton hydrates were found to give rise to much less anion fragmentation and constitute the softest protonation agents thus far identified for manipulating the charge states of multiply charged biopolymer anions. The reaction exothermicities associated with proton hydrates comprised of five or more water molecules are lower than that for protonated proton sponge, which is among the softest reagents thus far examined for ion/ion proton transfer reactions. The partitioning of ion/ion reaction exothermicity among all of the degrees of freedom of the products may also differ for proton hydrates relative to protonated molecules. However, a difference in energy partitioning need not be invoked to rationalize the results reported here.

  18. Far Ultraviolet Imaging from the Image Spacecraft

    NASA Technical Reports Server (NTRS)

    Mende, S. B.; Heetderks, H.; Frey, H. U.; Lampton, M.; Geller, S. P.; Stock, J. M.; Abiad, R.; Siegmund, O. H. W.; Tremsin, A. S.; Habraken, S.

    2000-01-01

    Direct imaging of the magnetosphere by the IMAGE spacecraft will be supplemented by observation of the global aurora. The IMAGE satellite instrument complement includes three Far Ultraviolet (FUV) instruments. The Wideband Imaging Camera (WIC) will provide broad band ultraviolet images of the aurora for maximum spatial and temporal resolution by imaging the LBH N2 bands of the aurora. The Spectrographic Imager (SI), a novel form of monochromatic imager, will image the aurora, filtered by wavelength. The proton-induced component of the aurora will be imaged separately by measuring the Doppler-shifted Lyman-a. Finally, the GEO instrument will observe the distribution of the geocoronal emission to obtain the neutral background density source for charge exchange in the magnetosphere. The FUV instrument complement looks radially outward from the rotating IMAGE satellite and, therefore, it spends only a short time observing the aurora and the Earth during each spin. To maximize photon collection efficiency and use efficiently the short time available for exposures the FUV auroral imagers WIC and SI both have wide fields of view and take data continuously as the auroral region proceeds through the field of view. To minimize data volume, the set of multiple images are electronically co-added by suitably shifting each image to compensate for the spacecraft rotation. In order to minimize resolution loss, the images have to be distort ion-corrected in real time. The distortion correction is accomplished using high speed look up tables that are pre-generated by least square fitting to polynomial functions by the on-orbit processor. The instruments were calibrated individually while on stationary platforms, mostly in vacuum chambers. Extensive ground-based testing was performed with visible and near UV simulators mounted on a rotating platform to emulate their performance on a rotating spacecraft.

  19. Dynamic Protonation Equilibrium of Solvated Acetic Acid

    SciTech Connect

    Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

    2007-04-13

    For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

  20. Proton Emission from Neutron Deficient Nuclei

    SciTech Connect

    Rodrigues, M. M. N.; Duarte, S. B.; Tavares, O. A. P.; Medeiros, E. L.; Teruya, N.

    2010-05-21

    We calculate the one-proton emission rate of nuclei near the proton drip line based on the WKB-approximation to determine Gamow's penetrability factor. An analytical potential barrier parametrization is proposed, and the obtained results in the calculation are in good agreement with existing experimental data for one-proton emitters. In addition, the sum-energy distribution for two-proton emission from {sup 45}Fe is also determined. This decay mode has been observed by Miernik et al.[Phys. Rev. Lett. 99, 192501 (2007)], where the measured two-proton energy distribution for simultaneous emission has been also reported. We show that this energy distribution is well reproduced with the statistical assumption of two-proton emission being described by a product of the calculated individual one-proton emission rates.

  1. How long solar proton radiation belts exists?

    NASA Astrophysics Data System (ADS)

    Lazutin, Leonid; Logachev, Yurii; Muravjeva, E.

    Solar protons of 1-5 MeV range were trapped during recovery phases of the strong magnetic storms on October 2003, July and November 2004 and after additional acceleration remain in the proton radiation belts for a long time. Using measurements of the low-altitude polar satel-lites CORONAS-F, SERVIS-1 and TATJANA-UNIVERSITETSKY we found, that enhanced proton flux of the 15 MeV energy remains about half a year at L=3-5, and about one year protons with 1 MeV energy. Additional 1 MeV proton belt at L=1.8-2.2 existed continuously from October 2003 at least to December 2006. Extrapolation of the measurements to the pre-vious 11-year cycles shows that solar proton contribution to the proton radiation belt of 1-5 MeV energy range may be important for the half of the solar cycle time.

  2. Radiobiology Using Laser Driven Protons

    NASA Astrophysics Data System (ADS)

    Kakolee, K.; Doria, D.; Kar, S.; Litt, S.; Zepf, M.; Borghesi, M.; Fiorini, F.; Kirby, D.; Green, S.; Kirkby, K.; Jeynes, C.; Merchant, M.

    2010-11-01

    The advantage of using ion beams in radiotherapy is easily understood in terms of the Bragg peak effect if compared to widely used x-ray irradiation systems. There is therefore a large literature about cell irradiation using ions from conventional accelerators. Employing the TARANIS Terawatt laser at Queen's University, the effect of proton irradiation of biological cells, on timescales orders of magnitude shorter than with conventional accelerators, has been investigated. The laser driven MeV proton beam has been energy dispersed by using a magnetic system prior to the irradiation, allowing simultaneous irradiation of a number of cell spots with different doses on a ns timescale. Consistent lethal effects on V-79 cancer cells have been observed.

  3. Proton synchrotron radiation at Fermilab

    SciTech Connect

    Thurman-Keup, Randy; /Fermilab

    2006-05-01

    While protons are not generally associated with synchrotron radiation, they do emit visible light at high enough energies. This paper presents an overview of the use of synchrotron radiation in the Tevatron to measure transverse emittances and to monitor the amount of beam in the abort gap. The latter is necessary to ensure a clean abort and prevent quenches of the superconducting magnets and damage to the silicon detectors of the collider experiments.

  4. Proton Resonance Spectroscopy -- Final Report

    SciTech Connect

    Shriner, Jr, J F

    2009-07-27

    This report summarizes work supported by the DOE Grant DE-FG02-96ER40990 during its duration from June 1996 to May 2009. Topics studied include (1) statistical descriptions of nuclear levels and measurements of proton resonances relevant to such descriptions, including measurements toward a complete level scheme for 30P, (2) the development of methods to estimate the missing fraction of levels in a given measurement, and (3) measurements at HRIBF relevant to nuclear astrophysics.

  5. Direct Observation of Two Proton Radioactivity Using Digital Photography

    SciTech Connect

    Rykaczewski, Krzysztof Piotr; Pfutzner, M.; Dominik, Wojciech; Janas, Z.; Miernik, K.; Bingham, C. R.; Czyrkowski, Henryk; Cwiok, Mikolaj; Darby, Iain; Dabrowski, Ryszard; Ginter, T. N.; Grzywacz, Robert Kazimierz; Karny, M.; Korgul, A.; Kusmierz, Waldemar; Liddick, Sean; Rajabali, Mustafa; Stolz, A.

    2007-01-01

    Recently the observation of a new type of spontaneous radioactive decay has been claimed in which two protons are simultaneously ejected by an atomic nucleus from the ground state1,2,3. Experimental data obtained for the extremely neutron-deficient nuclei 45Fe and 54Zn, were interpreted as the first evidence of such a decay mode which has been sought since 1960.4 However, the technique applied in those studies allowed only measurements of the decay time and the total energy released. Particles emitted in the decay were not identified and the conclusions had to be supported by theoretical arguments. Here we show for the first time, directly and unambiguously, that 45Fe indeed disintegrates by two-proton decay. Furthermore, we demonstrate that the decay branch of this isotope leads to various particle emission channels including two-proton and three-proton emission. To achieve this result we have developed a new type of detector V the Optical Time Projection Chamber (OTPC) in which digital photography is applied to nuclear physics for the first time. The detector records images of tracks from charged particles, allowing for their unambiguous identification and the reconstruction of decay events in three dimensions. This new and simple technique provides a powerful method to identify exotic decay channels involving emission of charged particles. It is expected that further studies with the OTPC device will yield important information on nuclei located at and beyond the proton drip-line, thus providing new material for testing and improving models of very unstable atomic nuclei.

  6. Proton Aurora Dynamics in Response to the IMF and Solar Wind Variations

    NASA Technical Reports Server (NTRS)

    Chang, S.; Mende, S.; Frey, H.; Gallagher, D. L.; Lepping, R. P.; Six, N. Frank (Technical Monitor)

    2002-01-01

    On May 23, 2000, proton auroras observed by IMAGE (Imager for Magnetopause to Aurora Global Exploration) FUV (Far Ultraviolet) on the dayside were very dynamic. Auroral pattern in the cusp is well correlated with Interplanetary Magnetic Field (IMF) and solar wind parameters. When IMF were northward, cusp proton aurora appeared at high latitude poleward from the auroral oval. A high-latitude proton aurora brightened after solar wind ion temperature increased and it disappeared after IMF turned southward. Under the southward IMF condition, auroral activity occurred only in the dayside auroral oval. As IMF $B_z$ reverted to northward, cusp proton aurora reappeared at high latitude. The magnetic local time of the cusp proton aurora changes with the IMF $B_y$ polarity, consistent with previous reports. These results suggest an upstream source of the high-latitude cusp proton aurora for this event. One possible explanation is that bow shock energetic ions are transported into the cusp via the high-latitude magnetic merging process to induce optical emissions in the ionosphere.

  7. Development of a proton Computed Tomography detector system

    NASA Astrophysics Data System (ADS)

    Naimuddin, Md.; Coutrakon, G.; Blazey, G.; Boi, S.; Dyshkant, A.; Erdelyi, B.; Hedin, D.; Johnson, E.; Krider, J.; Rukalin, V.; Uzunyan, S. A.; Zutshi, V.; Fordt, R.; Sellberg, G.; Rauch, J. E.; Roman, M.; Rubinov, P.; Wilson, P.

    2016-02-01

    Computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantegeous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

  8. Solid-state proton conductors

    SciTech Connect

    Jewulski, J.R.; Osif, T.L.; Remick, R.J.

    1990-12-01

    The purpose of this program was to survey the field of solid-state proton conductors (SSPC), identify conductors that could be used to develop solid-state fuel cells suitable for use with coal derived fuel gases, and begin the experimental research required for the development of these fuel cells. This document covers the following topics: the history of developments and current status of the SSPC, including a review of proton conducting electrolyte structures, the current status of the medium temperature SSPC development, electrodes for moderate temperature (SSPC) fuel cell, basic material and measurement techniques applicable for SSPC development, modeling and optimization studies. Correlation and optimization studies, to include correlation studies on proton conduction and oxide cathode optimization for the SSPC fuel cell. Experiments with the SSPC fuel cells including the fabrication of the electrolyte disks, apparatus for conducting measurements, the strontium-cerium based electrolyte, the barium-cerium based electrolyte with solid foil electrodes, the barium-cerium based electrolyte with porous electrodes, and conduction mechanisms. 164 refs., 27 figs., 13 tabs.

  9. High-Intensity Proton Accelerator

    SciTech Connect

    Jay L. Hirshfield

    2011-12-27

    Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

  10. Antiquark distributions in the proton

    SciTech Connect

    Brooks, M.; Carey, T.; Garvey, G.

    1997-07-01

    This is the final report of a three-year Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The study of quark and antiquark distributions in the nucleon has been a major endeavor in nuclear and particle physics. Results from a recent deep-inelastic scattering experiment suggest the surprising possibility that the up and down antiquark distributions in the proton are not symmetric. A sensitive and direct determination of the antiquark distributions in the proton can be made by comparing the Drell-Yan cross sections on hydrogen versus deuterium targets. The authors have proposed a new experiment (E866) at Fermilab to carry out such measurements. E866 has been taking data since September 1996. Preliminary results show that the apparatus is working very well. The authors anticipate having seven months of beam in 1997, which would allow them to achieve the sensitivities for a definitive measurement of flavor symmetry of sea quarks in the proton.

  11. Proton Beams from Nanotube Accelerator

    NASA Astrophysics Data System (ADS)

    Murakami, Masakatsu; Tanaka, Motohiko

    2013-10-01

    A carbon nanotube (CNT) is known to have extraordinary material and mechanical properties. Here we propose a novel ion acceleration scheme with nanometer-size CNT working at such an extreme circumstance as temperatures higher than billions of degree and durations shorter than tens of femtosecond, dubbed as nanotube accelerator, with which quasimonoenergetic and collimated MeV-order proton beams are generated. In nanotube accelerators, CNTs with fragments of a hydrogen compound embedded inside are irradiated by an ultrashort ultraintense laser. Under such laser and target conditions, low-Z materials such as hydrogen and carbon will be fully ionized. Substantial amount of electrons of the system are then blown off by the brutal laser electric field within only a few laser cycles. This leads to a new type of ion acceleration, in which the nanotube and embedded materials play the roles of a gun barrel and bullets, respectively, to produce highly collimated and quasimonoenergetic proton beams. Three-dimensional particle simulations, that take all the two-body Coulomb interactions into account, demonstrate generation of quasimonoenergetic 1.5-MeV proton beams under a super-intense electrostatic field ~ 1014 V m-1.

  12. Proton Radiation Therapy for Head and Neck Cancer: A Review of the Clinical Experience to Date

    SciTech Connect

    Holliday, Emma B.; Frank, Steven J.

    2014-06-01

    Proton beam radiation has been used for cancer treatment since the 1950s, but recent increasing interest in this form of therapy and the construction of hospital-based and clinic-based facilities for its delivery have greatly increased both the number of patients and the variety of tumors being treated with proton therapy. The mass of proton particles and their unique physical properties (ie, the Bragg peak) allow proton therapy to spare normal tissues distal to the tumor target from incidental irradiation. Initial observations show that proton therapy is particularly useful for treating tumors in challenging locations close to nontarget critical structures. Specifically, improvements in local control outcomes for patients with chordoma, chonodrosarcoma, and tumors in the sinonasal regions have been reported in series using proton. Improved local control and survival outcomes for patients with cancer of the head and neck region have also been seen with the advent of improvements in better imaging and multimodality therapy comprising surgery, radiation therapy, and chemotherapy. However, aggressive local therapy in the proximity of critical normal structures to tumors in the head and neck region may produce debilitating early and late toxic effects. Great interest has been expressed in evaluating whether proton therapy can improve outcomes, especially early and late toxicity, when used in the treatment of head and neck malignancies. This review summarizes the progress made to date in addressing this question.

  13. Physiologic Reactions After Proton Beam Therapy in Patients With Prostate Cancer: Significance of Urinary Autoactivation

    SciTech Connect

    Shimizu, Masakazu; Sasaki, Ryohei Miyawaki, Daisuke; Nishimura, Hideki; Demizu, Yusuke; Akagi, Takashi; Suga, Daisaku; Sakamoto, Hidenobu; Murakami, Masao; Sugimura, Kazuro; Hishikawa, Yoshio

    2009-10-01

    Purpose: Proton therapy is a sophisticated treatment modality for prostate cancer. We investigated how physiologic factors affected the distribution of autoactivation as detected by positron emission tomography (PET) after proton beam therapy. Methods and Materials: Autoactivation was evaluated in 59 patients treated with a 210-MeV proton beam. Data acquisition for autoactivation by PET started 5minutes after proton irradiation to assess activation. In the first 29 patients, five regions of interest were evaluated: planning target volume (PTV) center, urinary bladder inside the PTV, urinary bladder outside the PTV, rectum (outside the PTV), and contralateral femoral bone head (outside the PTV). In the remaining 30 patients, urine activity was measured directly. In a phantom study autoactivation and its diffusion after proton beam irradiation were evaluated with water or an ice block. Results: Mean activities calculated by use of PET were 629.3Bq in the PTV center, 555.6Bq in the urinary bladder inside the PTV, 332.5Bq in the urinary bladder outside the PTV, 88.4Bq in the rectum, and 23.7Bq in the femoral bone head (p < 0.001). Mean urine activity was 679.4Bq, recorded 10minutes after therapy completion, and the half-life for urine autoactivation was 4.5minutes. Conclusions: Urine is a major diffusion mediator of autoactivation after proton beam therapy. Our results indicate that physiologic factors can influence PET images of autoactivation in the context of proton beam therapy verification.

  14. Water-soluble core/shell nanoparticles for proton therapy through particle-induced radiation

    NASA Astrophysics Data System (ADS)

    Park, Jeong Chan; Jung, Myung-Hwan; Kim, Maeng Jun; Kim, Kye-Ryung

    2015-02-01

    Metallic nanoparticles have been used in biomedical applications such as magnetic resonance imaging (MRI), therapy, and drug delivery systems. Metallic nanoparticles as therapeutic tools have been demonstrated using radio-frequency magnetic fields or near-infrared light. Recently, therapeutic applications of metallic nanomaterials combined with proton beams have been reported. Particle-induced radiation from metallic nanoparticles, which can enhance the therapeutic effects of proton therapy, was released when the nanoparticles were bombarded by a high-energy proton beam. Core/shell nanoparticles, especially Au-coated magnetic nanoparticles, have drawn attention in biological applications due to their attractive characteristics. However, studies on the phase transfer of organic-ligand-based core/shell nanoparticles into water are limited. Herein, we demonstrated that hydrophobic core/shell structured nanomaterials could be successfully dispersed in water through chloroform/surfactant mixtures. The effects of the core/shell nanomaterials and the proton irradiation on Escherichia coli (E. coli) were also explored.

  15. Absorption characteristics of protons and photons in tissue.

    PubMed

    Dicello, John F

    2007-08-01

    This presentation reviews the radiation quality of protons and other energetic ion beams, where radiation quality refers to those relevant physical properties other than the dose of the different types of radiations that can contribute to differences in the absorption characteristics in various tissues and the corresponding clinical outcomes. Prior to initiation of clinical trials with protons, neutrons, pions, and heavy ions, it was generally believed that such particles might have a therapeutic advantage resulting from their greater relative biological effectiveness (RBE). Potential clinical advantages resulting from a greater biological effectiveness, however, have generally been overshadowed during the last three decades by improved controls or reduced complications resulting primarily from the better dose delivery and localization that was possible with these heavier particles in conjunction with improved imaging. The successes both in delivery and in the clinical responses with protons and other light ions resulting from improved dose localization have arguably led the way in stereotactic radiosurgery, intensity modulated radiation therapy, and tomotherapy, stimulating improved methods with conventional radiations as well. Protons or light ions differ significantly in comparison with photon or electron beams in how they interact with the tissue atoms and molecules, and in how they transfer energy to those tissues. Microscopically, the heavier particles tend to travel in straight lines and produce long tracks with the energy concentrated closer to the track of the primary particle, while photons or electrons tend to scatter more easily and produce a more uniform distribution of energy transfers. Because they are hadrons, i.e., nuclear particles, protons and ions are more likely to produce long-range nuclear secondaries with higher masses. This higher concentration of energy associated with the heavier particle beams and the more massive secondaries results in differences in dose localization, clinically and microscopically, and therefore potential differences in short-term and long-term chemical and biological processes. Protons tend to have the least differences in clinical response in comparison with photons and electrons, the radiations used conventionally in therapy, but biological differences have been observed for these particles; it behooves us, therefore, to understand these different mechanisms if we are to take full advantage of their benefits. This article reviews the physical properties of these different particles in terms of microdosimetric distributions of energy deposition in order to compare protons with photons and heavy ions. PMID:17668948

  16. SU-E-J-35: Clinical Performance Evaluation of a Phase II Proton CT Scanner

    SciTech Connect

    Mandapaka, A; Ghebremedhin, A; Farley, D; Giacometti, V; Vence, N; Bashkirov, V; Patyal, B; Schulte, R; Plautz, T; Zatserklyaniy, A; Johnson, R; Sadrozinski, H

    2014-06-01

    Purpose: To develop the methodology to evaluate the clinical performance of a Phase II Proton CT scanner Methods: Range errors on the order of 3%-5% constitute a major uncertainty in current charged particle treatment planning based on Hounsfield Unit (HU)-relative stopping power (RSP) calibration curves. Within our proton CT collaboration, we previously developed and built a Phase I proton CT scanner that provided a sensitive area of 9 cm (axial) 18 cm (in-plane). This scanner served to get initial experience with this new treatment planning tool and to incorporate lessons learned into the next generation design. A Phase II scanner was recently completed and is now undergoing initial performance testing. It will increase the proton acquisition rate and provide a larger detection area of 9 cm x 36 cm. We are now designing a comprehensive evaluation program to test the image quality, imaging dose, and range uncertainty associated with this scanner. The testing will be performed along the lines of AAPM TG 66. Results: In our discussion of the evaluation protocol we identified the following priorities. The image quality of proton CT images, in particular spatial resolution and low-density contrast discrimination, will be evaluated with the Catphan600 phantom. Initial testing showed that the Catphan uniformity phantom did not provide sufficient uniformity; it was thus replaced by a cylindrical water phantom. The imaging dose will be tested with a Catphan dose module, and compared to a typical cone beam CT dose for comparable image quality. Lastly, we developed a dedicated dosimetry range phantom based on the CIRS pediatric head phantom HN715. Conclusion: A formal evaluation of proton CT as a new tool for proton treatment planning is an important task. The availability of the new Phase II proton CT scanner will allow us to perform this task. This research is supported by the National Institute of Biomedical Imaging and Bioengineering of the NIH under award number R01EB013118. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

  17. {beta}-delayed proton decays near the proton drip line

    SciTech Connect

    Xu, S.-W.; Li, Z.-K.; Xie, Y.-X.; Pan, Q.-Y.; Huang, W.-X.; Wang, X.-D.; Yu, Y.; Xing, Y.-B.; Shu, N.-C.; Chen, Y.-S.; Xu, F.-R.; Wang, K.

    2005-05-01

    We briefly reviewed and summarized the experimental study on {beta}-delayed proton decays published by our group over the last 8 years, namely the experimental observation of {beta}-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N{approx}Z by utilizing the p-{gamma} coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for {sup 85}Mo, {sup 92}Rh, as well as the predicted 'waiting point' nuclei {sup 89}Ru and {sup 93}Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the predictions of the mass abundances of the nuclides produced in the rp process. (2) The experimental assignments of spin and parity for the drip-line nuclei {sup 142}Ho and {sup 128}Pm could not be well predicted by any of the nuclear models. Nevertheless, the configuration-constrained nuclear potential-energy surfaces calculated by means of a Woods-Saxon-Strutinsky method could reproduce the assignments. (3) The ALICE code overestimated by one or two orders of magnitude the production-reaction cross sections of the nine studied rare-earth nuclei, while the HIVAP code overestimated them by approximately one order of magnitude.

  18. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun

    1990-12-31

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  19. Proton-proton and proton-antiproton elastic scattering at high energies: Theory, phenomenology, and experiment

    SciTech Connect

    Wu, Tai Tsun.

    1990-01-01

    This is a brief review of the progress in the understanding, during the past twenty years, of hadronic elastic scattering near the forward direction at high energies. On the basis of quantum gauge field theories, the Pomeron is found to be a branch cut above 1. Using the physical picture that this result implies, phenomenology for proton-proton and antiproton-proton elastic scattering is constructed. Two noteworthy features are that, at high energies, both the total cross section and the ratio of the integrated elastic cross section to the total cross section to the total cross section are increasing functions of the center-of-mass energy. Detailed predictions are given for the elastic differential cross sections, Coulomb interference and the ratios of the real to imaginary parts of the forward amplitudes. These predictions have been extensively and accurately confirmed by experiments, and have also been given both for future experiments on existing accelerators and for experiments on future accelerators. 14 refs., 2 figs.

  20. The M. D. Anderson proton therapy system

    SciTech Connect

    Smith, Alfred; Gillin, Michael; Bues, Martin; Zhu, X. Ronald; Suzuki, Kazumichi; Mohan, Radhe; Woo, Shiao; Lee, Andrew; Komaki, Ritsko; Cox, James; Hiramoto, Kazuo; Akiyama, Hiroshi; Ishida, Takayuki; Sasaki, Toshie; Matsuda, Koji

    2009-09-15

    Purpose: The purpose of this study is to describe University of Texas M. D. Anderson proton therapy system (PTC-H) including the accelerator, beam transport, and treatment delivery systems, the functionality and clinical parameters for passive scattering and pencil beam scanning treatment modes, and the results of acceptance tests. Methods: The PTC-H has a synchrotron (70-250 MeV) and four treatment rooms. An overall control system manages the treatment, physics, and service modes of operation. An independent safety system ensures the safety of patients, staff, and equipment. Three treatment rooms have isocentric gantries and one room has two fixed horizontal beamlines, which include a large-field treatment nozzle, used primarily for prostate treatments, and a small-field treatment nozzle for ocular treatments. Two gantry treatment rooms and the fixed-beam treatment room have passive scattering nozzles. The third gantry has a pencil beam scanning nozzle for the delivery of intensity modulated proton treatments (IMPT) and single field uniform dose (SFUD) treatments. The PTC-H also has an experimental room with a fixed horizontal beamline and a passive scattering nozzle. The equipment described above was provided by Hitachi, Ltd. Treatment planning is performed using the Eclipse system from Varian Medical Systems and data management is handled by the MOSAIQ system from IMPAC Medical Systems, Inc. The large-field passive scattering nozzles use double scattering systems in which the first scatterers are physically integrated with the range modulation wheels. The proton beam is gated on the rotating range modulation wheels at gating angles designed to produce spread-out-Bragg peaks ranging in size from 2 to 16 g/cm{sup 2}. Field sizes of up to 25x25 cm{sup 2} can be achieved with the double scattering system. The IMPT delivery technique is discrete spot scanning, which has a maximum field size of 30x30 cm{sup 2}. Depth scanning is achieved by changing the energy extracted from the synchrotron (energy can be changed pulse to pulse). The PTC-H is fully integrated with DICOM-RT ION interfaces for imaging, treatment planning, data management, and treatment control functions. Results: The proton therapy system passed all acceptance tests for both passive scattering and pencil beam scanning. Treatments with passive scattering began in May 2006 and treatments with the scanning system began in May 2008. The PTC-H was the first commercial system to demonstrate capabilities for IMPT treatments and the first in the United States to treat using SFUD techniques. The facility has been in clinical operation since May 2006 with up-time of approximately 98%. Conclusions: As with most projects for which a considerable amount of new technology is developed and which have duration spanning several years, at project completion it was determined that several upgrades would improve the overall system performance. Some possible upgrades are discussed. Overall, the system has been very robust, accurate, reproducible, and reliable. The authors found the pencil beam scanning system to be particularly satisfactory; prostate treatments can be delivered on the scanning nozzle in less time than is required on the passive scattering nozzle.

  1. Contribution of proton precipitation to space-based auroral FUV observations

    NASA Astrophysics Data System (ADS)

    Galand, M.; Lummerzheim, D.; Frey, H. U.; Paxton, L. J.; Christensen, A. B.

    2002-12-01

    Energetic electrons and protons precipitating from the magnetosphere are a major energy source in the high latitude regions inducing significant ionospheric and thermospheric perturbations through ionization and heating. The aurora is the optical manifestation of the interaction of these energetic particles with atmospheric neutrals. Auroral brightnesses and brightness ratios can be used to determine the particle characteristics for estimation of the subsequent atmospheric response or for tracking magnetospheric processes. Imaging from space offers a unique way to access to the global picture, and its temporal varibility, of the particle energy input over the auroral ovals. Usually only the electron component of the precipitation is considered. Electron characteristics are inferred from the analysis of auroral images taken from space in two different spectral bands in UV or visible. In the aurora most of the energy is carried by electrons, but at some locations and certain times protons are a major energy source, that is, a major ionization source of the atmosphere. The response of POLAR/UVI, IMAGE/WIC and SI13, and TIMED/GUVI -used for retrieving the electron components- to proton precipitation will be estimated. Secondary electrons produced within the proton beam also contribute to auroral emissions. Since they are less energetic than the secondary electrons produced in electron precipitation, they have a different spectral signature. In addition, for a given energy flux, protons are usually more efficient at ionizing than electrons and yield larger values of the Pedersen ionospheric conductance. Therefore, the difference between proton and electron aurora can lead to misinterpretation when brightness ratios are used to derive ionospheric conductances with parameterizations that are based on electron aurora. The validation and limitations of auroral analysis will be discussed, especially in the winter cusp region and at the equatorward edge of the afternoon oval, where protons are expected to be a significant energy source.

  2. CRRES high energy proton flux maps

    SciTech Connect

    Gussenhoven, M.S.; Mullen, E.G.; Violet, M.D. . Phillips Lab.); Hein, C.; Bass, J. ); Madden, D. )

    1993-12-01

    The Combined Release and Radiation Effects Satellite (CRRES) hosted the most sophisticated complement of high energy particle detectors ever flown in the inner magnetosphere. Proton flux maps of near-Earth space are presented using the Proton Telescope (PROTEL) detector on CRRES. The proton energy range covered is 1--100 MeV. Contamination of PROTEL measurements due to > 100 MeV protons is corrected using loss cone data, resulting in consistency with dosimeter measurements and a Monte Carlo computer model of PROTEL. Two states of the inner magnetosphere were found during the CRRES mission, a quiet state having a single proton belt, and an active state with a double belt. The properties of the new population in the second belt are presented. Comparisons with NASA proton codes are made.

  3. Commissioning of the PRIOR proton microscope

    NASA Astrophysics Data System (ADS)

    Varentsov, D.; Antonov, O.; Bakhmutova, A.; Barnes, C. W.; Bogdanov, A.; Danly, C. R.; Efimov, S.; Endres, M.; Fertman, A.; Golubev, A. A.; Hoffmann, D. H. H.; Ionita, B.; Kantsyrev, A.; Krasik, Ya. E.; Lang, P. M.; Lomonosov, I.; Mariam, F. G.; Markov, N.; Merrill, F. E.; Mintsev, V. B.; Nikolaev, D.; Panyushkin, V.; Rodionova, M.; Schanz, M.; Schoenberg, K.; Semennikov, A.; Shestov, L.; Skachkov, V. S.; Turtikov, V.; Udrea, S.; Vasylyev, O.; Weyrich, K.; Wilde, C.; Zubareva, A.

    2016-02-01

    Recently, a new high energy proton microscopy facility PRIOR (Proton Microscope for FAIR Facility for Anti-proton and Ion Research) has been designed, constructed, and successfully commissioned at GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany). As a result of the experiments with 3.5-4.5 GeV proton beams delivered by the heavy ion synchrotron SIS-18 of GSI, 30 μm spatial and 10 ns temporal resolutions of the proton microscope have been demonstrated. A new pulsed power setup for studying properties of matter under extremes has been developed for the dynamic commissioning of the PRIOR facility. This paper describes the PRIOR setup as well as the results of the first static and dynamic proton radiography experiments performed at GSI.

  4. Commissioning of the PRIOR proton microscope.

    PubMed

    Varentsov, D; Antonov, O; Bakhmutova, A; Barnes, C W; Bogdanov, A; Danly, C R; Efimov, S; Endres, M; Fertman, A; Golubev, A A; Hoffmann, D H H; Ionita, B; Kantsyrev, A; Krasik, Ya E; Lang, P M; Lomonosov, I; Mariam, F G; Markov, N; Merrill, F E; Mintsev, V B; Nikolaev, D; Panyushkin, V; Rodionova, M; Schanz, M; Schoenberg, K; Semennikov, A; Shestov, L; Skachkov, V S; Turtikov, V; Udrea, S; Vasylyev, O; Weyrich, K; Wilde, C; Zubareva, A

    2016-02-01

    Recently, a new high energy proton microscopy facility PRIOR (Proton Microscope for FAIR Facility for Anti-proton and Ion Research) has been designed, constructed, and successfully commissioned at GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany). As a result of the experiments with 3.5-4.5 GeV proton beams delivered by the heavy ion synchrotron SIS-18 of GSI, 30 μm spatial and 10 ns temporal resolutions of the proton microscope have been demonstrated. A new pulsed power setup for studying properties of matter under extremes has been developed for the dynamic commissioning of the PRIOR facility. This paper describes the PRIOR setup as well as the results of the first static and dynamic proton radiography experiments performed at GSI. PMID:26931841

  5. 4D dose calculation and delivery with interplay effects between respiratory motion and uniform scanning proton beam

    NASA Astrophysics Data System (ADS)

    Zhao, Qingya

    2011-12-01

    Proton radiotherapy has advantages to deliver accurate high conformal radiation dose to the tumor while sparing the surrounding healthy tissue and critical structures. However, the treatment effectiveness is degraded greatly due to patient free breathing during treatment delivery. Motion compensation for proton radiotherapy is especially challenging as proton beam is more sensitive to the density change along the beam path. Tumor respiratory motion during treatment delivery will affect the proton dose distribution and the selection of optimized parameters for treatment planning, which has not been fully addressed yet in the existing approaches for proton dose calculation. The purpose of this dissertation is to develop an approach for more accurate dose delivery to a moving tumor in proton radiotherapy, i.e., 4D proton dose calculation and delivery, for the uniform scanning proton beam. A three-step approach has been carried out to achieve this goal. First, a solution for the proton output factor calculation which will convert the prescribed dose to machine deliverable monitor unit for proton dose delivery has been proposed and implemented. The novel sector integration method is accurate and time saving, which considers the various beam scanning patterns and treatment field parameters, such as aperture shape, aperture size, measuring position, beam range, and beam modulation. Second, tumor respiratory motion behavior has been statistically characterized and the results have been applied to advanced image guided radiation treatment. Different statistical analysis and correlation discovery approaches have been investigated. The internal / external motion correlation patterns have been simulated, analyzed, and applied in a new hybrid gated treatment to improve the target coverage. Third, a dose calculation method has been developed for 4D proton treatment planning which integrates the interplay effects of tumor respiratory motion patterns and proton beam delivery mechanism. These three steps provide an innovative integrated framework for accurate 4D proton dose calculation and treatment planning for a moving tumor, which extends the functionalities of existing 3D planning systems. In short, this dissertation work addresses a few important problems for effective proton radiotherapy to a moving target. The outcomes of the dissertation are very useful for motion compensation with advanced image guided proton treatment.

  6. An observation of proton-induced latchup

    NASA Technical Reports Server (NTRS)

    Nichols, Donald K.; Coss, James R.; Watson, R. K.; Schwartz, Harvey R.; Pease, Ronald L.

    1992-01-01

    Proton-induced latchup in a CMOS microprocessor known to have a very low heavy-ion-induced latchup threshold LET was observed. The latchup cross section vs. proton energy for three different bias conditions is displayed. Average measures of latchup current within an 11-ms window following the onset of latchup are provided, as a function of bias and incident proton energy. These data can be interpreted in terms of the present understanding of SEE phenomena.

  7. Molecular Mechanism of Biological Proton Transport

    SciTech Connect

    Pomes, R.

    1998-09-01

    Proton transport across lipid membranes is a fundamental aspec