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| 2. |
- Gratz, M, et al.
(author)
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Time-gated imaging in radiology: Theoretical and experimental studies
- 1996
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In: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X. ; 2:4, s. 1041-1048
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Journal article (peer-reviewed)abstract
- Novel short-pulse X-ray sources, e.g., laser-produced plasmas, offer new approaches to the solution of the scatter-reduction problem in X-ray imaging, by the use of time-gated detection techniques. Monte Carlo simulations are used to estimate the scatter-reduction performance of time-gated imaging techniques within a range of X-ray energies, gating times and tissue parameters, Significant improvements can be achieved for thick tissues combined with high photon energies, Experimental studies on water phantoms are performed using a laser-produced plasma X-ray source. Problems arising on the technical realization are discussed.
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| 3. |
- Herrlin, K, et al.
(author)
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Contrast-enhanced radiography by differential absorption, using a laser-produced X-ray source
- 1997
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In: Investigative Radiology. - 0020-9996. ; 32:5, s. 306-310
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Journal article (peer-reviewed)abstract
- RATIONALE AND OBJECTIVES. The authors evaluate the feasibility of differential imaging of contrast media, with division of individual pixel values obtained from digital images generated by characteristic radiation from a laser-produced plasma, bridging the K-absorption edge of the contrast agent. METHODS. Laser pulses from an ultrashort-pulse terawatt laser system were focused onto gadolinium and tantalum targets, creating a plasma from which characteristic radiation and Bremsstrahlung was emitted. The elements of the target were selected so the characteristic emission lines of one of the elements were below the K edge of the contrast agent and the emission lines of the other element above. A phantom with gadolinium and other elements in various concentrations was examined. One radiographic exposure was made using a gadolinium target source and a subsequent exposure using a tantalum source. Both images were recorded digitally and the transmission ratios calculated by division of the individual pixel values. RESULTS. When viewed separately, the two images of the test phantom appeared similar. In the differential image, only the gadolinium solutions were bright, reflecting a difference in attenuation between the two exposures. CONCLUSIONS. Element-specific radiographs can be obtained by differential imaging. When fully explored, the technique may allow for contrast-enhanced radiography with increased sensitivity and decreased contrast dose.
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| 4. |
- Svanberg, Sune, et al.
(author)
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Generation, characterization, and medical utilization of laser-produced emission continua
- 2000
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In: Laser and Particle Beams. - 0263-0346. ; 18:3, s. 563-570
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Journal article (peer-reviewed)abstract
- Intense continua of electromagnetic radiation of very brief duration are formed in the interaction of focused ultra-short terawatt laser pulses with matter. Two different kinds of experiments, which have been performed utilizing the Lund 10 Hz titanium-doped sapphire terawatt laser system are being described, where visible radiation and X-rays, respectively, have been generated. Focusing into water leads to the generation of a light continuum through self-phase modulation. The propagation of the light through tissue was studied addressing questions related to optical mammography and specific chromophore absorption. When terawatt laser pulses are focused onto a solid target with high nuclear charge Z, intense X-ray radiation of few ps duration and with energies exceeding hundreds of keV is emitted. Biomedical applications of this radiation are described, including differential absorption and gated-viewing imaging.
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