5 results for Aamir, R.

  • Reducing beam hardening effects and metal artefacts in spectral CT using Medipix3RX

    Rajendran, K; Walsh, M. F.; de Ruiter, N. J. A.; Chernoglazov, A. I.; Panta, R. K.; Butler, P. H.; Bell, S. T.; Woodfield, T. B. F.; Tredinnick, J.; Healy, J. L.; Bateman, C. J.; Aamir, R.; Doesburg, R. M. N.; Renaud, P. F.; Gieseg, S. P.; Smithies, D. J.; Mohr, J. L.; Mandalika, V. B. H.; Opie, A. M. T.; Cook, N. J.; Ronaldson, J. P.; Nik, S. J.; Atharifard, A.; Clyne, M.; Bones, P. J.; Bartneck, C.; Grasset, R.; Schleich, N.; Billinghurst, M.; Butler, A. P. H.; Anderson, N. G. (2014-02-05)

    Unclassified
    University of Canterbury Library

    DICOM Raw Data, with explanatory text files.

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  • Reducing beam hardening effects and metal artefacts using Medipix3RX: With applications from biomaterial science

    Rajendran, K.; Walsh, M.F.; de Ruiter, N.J.A.; Chernoglazov, A.I.; Panta, R.K.; Butler, A.P.H.; Butler, P.H.; Bell, S.T.; Anderson, N.G.; Woodfield, T.B.F.; Tredinnick, S.J.; Healy, J.L.; Bateman, C.J.; Aamir, R.; Doesburg, R.M.N.; Renaud, P.F.; Gieseg, S.P.; Smithies, D.J.; Mohr, J.L.; Mandalika, V.B.H.; Opie, A.M.T.; Cook, N.J.; Ronaldson, J.P.; Nik, S.J.; Atharifard, A.; Clyne, M.; Bones, P.J.; Bartneck, C.; Grasset, R.; Schleich, N.; Billinghurst, M. (2014)

    Journal Articles
    University of Canterbury Library

    This paper discusses methods for reducing beam hardening effects using spectral data for biomaterial applications. A small-animal spectral scanner operating in the diagnostic energy range was used. We investigate the use of photon-processing features of the Medipix3RX ASIC in reducing beam hardening and associated artefacts. A fully operational charge summing mode was used during the imaging routine. We present spectral data collected for metal alloy samples, its analysis using algebraic 3D reconstruction software and volume visualisation using a custom volume rendering software. Narrow high energy acquisition using the photon-processing detector revealed substantial reduction in beam hardening effects and metal artefacts.

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  • Using Algebraic Reconstruction in Computed Tomography

    Tang, N.D.; de Ruiter, N.; Mohr, J.L.; Butler, A.P.H.; Aamir, R. (2012)


    University of Canterbury Library

    Spectral Computed Tomography (spectral CT) is a newly emerging, medical imaging modality. It extends CT by acquiring multiple datasets over different x-ray energy bins. As the x-ray absorption of materials is energy dependent, the energy bins together provide significantly more information about the composition of the subject. To exploit the full potential of spectral CT, there are many new image processing challenges including reconstruction, material decomposition, and visualization. This paper introduces the development of a unique reconstruction algorithm which fully exploits the nature of spectral CT data. A small application called mART was developed which implements a standard Simultaneous Algebraic Reconstruction Technique (SART). mART will form the basis for future research and development. We demonstrate that in its current form it produces reconstructions of superior quality to the commercial reconstruction package Octopus CT which is the standard software adopted by our team. In addition, future plans for the reconstruction algorithm will be discussed.

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  • Pixel sensitivity variation in a CdTe-Medipix2 detector using poly-energetic x-rays

    Aamir, R.; Lansley, S.P.; Zainon, R.; Fiederle, M.; Fauler, A.; Greiffenberg, D.; Butler, P.H.; Butler, A.P.H. (2011)

    Conference Contributions - Published
    University of Canterbury Library

    We have a 1-mm-thick cadmium telluride (CdTe) sensor bump-bonded to a Medipix2 readout chip. This detector has been characterized using a poly-energetic x-ray beam. Open beam images (i.e. without an attenuating specimen between the x-ray source and the detector) have been acquired at room temperature using the MARS-CT system. Profiles of various rows and columns were analyzed for one hundred, 35-ms exposures taken with a bias voltage of -300 V (operating in electron collection mode). A region of increased sensitivity is observed around the edges of the detector. A reasonably periodic, repeatable variation in pixel sensitivity is observed. Some small regions with very low sensitivity and others with zero signals are also observed. Surrounding these regions are circular rings of pixels with higher counts. At higher flux (higher tube current in the x-ray source) there is evidence of saturation of the detector assembly. In this paper we present our understanding of the origin of these features and demonstrate the improved image quality obtained after correcting for these variations.

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  • Reducing beam hardening effects and metal artefacts in spectral CT using Medipix3RX

    Rajendran, K; Walsh, M. F.; de Ruiter, N. J. A.; Chernoglazov, A. I.; Panta, R. K.; Butler, P. H.; Bell, S. T.; Woodfield, T. B. F.; Tredinnick, J.; Healy, J. L.; Bateman, C. J.; Aamir, R.; Doesburg, R. M. N.; Renaud, P. F.; Gieseg, S. P.; Smithies, D. J.; Mohr, J. L.; Mandalika, V. B. H.; Opie, A. M. T.; Cook, N. J.; Ronaldson, J. P.; Nik, S. J.; Atharifard, A.; Clyne, M.; Bones, P. J.; Bartneck, C.; Grasset, R.; Schleich, N.; Billinghurst, M.; Butler, A. P. H.; Anderson, N. G. (2013-11-21)

    Datasets
    University of Canterbury Library

    MARS Spectral Data

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