Diagnostic x‐ray spectra: A comparison of spectra generated by different computational methods with a measured spectrum

Bhat, Madhava; Pattison, John E.; Bibbo, Giovanni; Caon, Martin

doi:10.1118/1.598170

Cited by 89 publications

(54 citation statements)

References 7 publications

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“…The results as shown in Table 1 are in good agreement with the IPEM Report [51], Bhat et al [52] and Fewell et al [53] however, binning the data into 0.5 keV energy intervals causes small shift in characteristic x-ray energy. Our model allows using a tungsten source in 10-100 keV mean spectrum energy range.…”

Section: X-ray Tube Source Simulationssupporting

confidence: 81%

Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

Włodarczyk

Pietrzak

2015

Biomed. Opt. Express

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This paper presents analytical approach to modeling of a full planar and volumetric acquisition system with image reconstructions originated from partial illumination x-ray phase-contrast imaging at a human scale using graphics processor units. The model is based on x-ray tracing and wave optics methods to develop a numerical framework for predicting the performance of a preclinical phase-contrast imaging system of a human-scaled phantom. In this study, experimental images of simple numerical phantoms and high resolution anthropomorphic phantoms of head and thorax based on non-uniform rational b-spline shapes (NURBS) prove the correctness of the model. Presented results can be used to simulate the performance of partial illumination x-ray phase-contrast imaging system on various preclinical applications. (Wiley, New Jersey 2003). 2. T. Weitkamp, C. David, O. Bunk, J. Bruder, P. Cloetens, and F. Pfeiffer, "X-ray phase radiography and tomography of soft tissue using grating interferometry," Eur. J. Radiol. 68(3 Suppl), S13-S17 (2008). 3. S. A. Zhou and A. Brahme, "Development of phase-contrast x-ray imaging techniques and potential medical applications," Phys. Med. 24(3), 129-148 (2008). 4. C. Raven, A. Snigirev, I. Snigireva, P. Spanne, A. Souvorov, and V. Kohn, "Phase-contrast microtomography with coherent high-energy synchrotron X-rays," Appl. Phys. Lett. 69(13), 1826-1828 (1996). 5. F. Arfelli, M. Assante, V. Bonvicini, A. Bravin, G. Cantatore, E. Castelli, L. Dalla Palma, M. Di Michiel, R. ©2015 Optical Society of America References and links A. R. Webb, Introduction to Biomedical ImagingLongo, A. Olivo, S. Pani, D. Pontoni, P. Poropat, M. Prest, A. Rashevsky, G. Tromba, A. Vacchi, E. Vallazza, and F. Zanconati, "Low-dose phase contrast X-ray medical imaging," Phys. Med. Biol. 43(10), 2845-2852 (1998). 6. S. W. Wilkins, T. E. Gureyev, D. Gao, A. Pogany, and A. W. Stevenson, "Phase-contrast imaging using polychromatic hard X-rays," Nature 384(6607), 335-338 (1996). 7. D. Chapman, W. Thomlinson, R. E. Johnston, D. Washburn, E. Pisano, N. Gmür, Z. Zhong, R. Menk, F. Arfelli, and D. Sayers, "Diffraction enhanced x-ray imaging," Phys. Med. Biol. 42(11), 2015-2025 (1997). 8. A. Snigirev, I. Snigireva, V. Kohn, S. Kuznetsov, and I. Schelokov, "On the possibilities of x-ray phase contrast microimaging by coherent high-energy synchrotron radiation," Rev. Sci. Instrum. 66(12), 5486 (1995). 9. X. Wu and H. Liu, "Clarification of aspects in in-line phase-sensitive x-ray imaging," Med. Phys. 34(2), 737-743 (2007). 10. A. Momose, "Demonstration of phase-contrast X-ray computed tomography using an X-ray interferometer," Nucl. Instrum. Methods Phys.

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Section: X-ray Tube Source Simulationssupporting

confidence: 81%

Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

Włodarczyk

Pietrzak

2015

Biomed. Opt. Express

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“…The output spectra of tungsten-anode x-ray tubes have been measured by Bhat and co-authors for several generator input voltages (Bhat et al 1998). At 80 kVp input the spectrum peaks at 32 keV and The spectrum peaks at 32 keV and has a full width at half maximum (FWHM) of 30 keV.…”

Section: Discussionmentioning

confidence: 99%

Dynamic fluorescence imaging of the free radical products of X-ray absorption in live cells

2012

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The immediate products of x-ray absorption in aqueous biological samples are free radicals including *OH, H 2 O 2 , *H and solvated electrons. Because their lifetimes and diffusion ranges are dependent on the local bio-molecular environment, imaging these free radicals in real-time while they are produced by a scanning x-ray nanobeam may provide a biological microscopy method of high resolution. As a first step towards this goal, we investigated the feasibility of imaging the initial free radical products of x-ray absorption in live cells using fluorescent free radical sensors. We selected six commercially available fluorescent sensors for screening tests of their sensitivities towards x-ray radiation in solution form. Two of the six dyes were found to have high sensitivities. One of the two was successfully used for dynamic confocal fluorescence imaging of x-ray generated free radicals in the intracellular space of mouse embryonic fibroblasts. Time series of fluorescence images before and during x-ray radiation were acquired. The rate of increase of cellular fluorescence showed both the initial production of free radicals by the physical ionization events as well as stimulated biological production of reactive oxygen species later on. The implications of the results for future development of microscopy techniques are discussed.

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“…The model-based methods usually generate spectra from empirical or semiempirical physical models [1][2][3][4][5][6] and the measurement-based methods reconstruct spectra from measured data, essentially making an indirect measurement of the spectra. [7][8][9][10][11][12][13][14][15][16] The transmission method is one of the measurement-based methods.…”

Section: Introductionmentioning

confidence: 99%

CT scanner x‐ray spectrum estimation from transmission measurements

Duan¹,

Wang²,

Yu³

et al. 2011

Medical Physics

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Purpose:In diagnostic CT imaging, multiple important applications depend on the knowledge of the x-ray spectrum, including Monte Carlo dose calculations and dual-energy material decomposition analysis. Due to the high photon flux involved, it is difficult to directly measure spectra from the x-ray tube of a CT scanner. One potential method for indirect measurement involves estimating the spectrum from transmission measurements. The expectation maximization ͑EM͒ method is an accurate and robust method to solve this problem. In this article, this method was evaluated in a commercial CT scanner. Methods: Two step-wedges ͑polycarbonate and aluminum͒ were used to produce different attenuation levels. Transmission measurements were performed on the scanner and the measured data from the scanner were exported to an external computer to calculate the spectra. The EM method was applied to solve the equations that represent the attenuation processes of polychromatic x-ray photons. Estimated spectra were compared to the spectra simulated using a software provided by the manufacturer of the scanner. To test the accuracy of the spectra, a verification experiment was performed using a phantom containing different depths of water. The measured transmission data were compared to the transmission values calculated using the estimated spectra. Results: Spectra of 80, 100, 120, and 140 kVp from a dual-source CT scanner were estimated. The estimated and simulated spectra were well matched. The differences of mean energies were less than 1 keV. In the verification experiment, the measured and calculated transmission values were in excellent agreement. Conclusions: Spectrum estimation using transmission data and the EM method is a quantitatively accurate and robust technique to estimate the spectrum of a CT system. This method could benefit studies relying on accurate knowledge of the x-ray spectra from CT scanner.

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Diagnostic x‐ray spectra: A comparison of spectra generated by different computational methods with a measured spectrum

Cited by 89 publications

References 7 publications

Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

Analytical reconstructions of intensity modulated x-ray phase-contrast imaging of human scale phantoms

Dynamic fluorescence imaging of the free radical products of X-ray absorption in live cells

CT scanner x‐ray spectrum estimation from transmission measurements

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