PURPOSE: To investigate the feasibility of characterizing a Si strip photon-counting detector using x-ray fluorescence. METHODS: X-ray fluorescence was generated by using a pencil beam from a tungsten anode x-ray tube with 2 mm Al filtration. Spectra were acquired at 90° from the primary beam direction with an energy-resolved photon-counting detector based on an edge illuminated Si strip detector. The distances from the source to target and the target to detector were approximately 19 and 11 cm, respectively. Four different materials, containing silver (Ag), iodine (I), barium (Ba), and gadolinium (Gd), were placed in small plastic containers with a diameter of approximately 0.7 cm for x-ray fluorescence measurements. Linear regression analysis was performed to derive the gain and offset values for the correlation between the measured fluorescence peak center and the known fluorescence energies. The energy resolutions and charge-sharing fractions were also obtained from analytical fittings of the recorded fluorescence spectra. An analytical model, which employed four parameters that can be determined from the fluorescence calibration, was used to estimate the detector response function. RESULTS: Strong fluorescence signals of all four target materials were recorded with the investigated geometry for the Si strip detector. The average gain and offset of all pixels for detector energy calibration were determined to be 6.95 mV/keV and -66.33 mV, respectively. The detector's energy resolution remained at approximately 2.7 keV for low energies, and increased slightly at 45 keV. The average charge-sharing fraction was estimated to be 36% within the investigated energy range of 20-45 keV. The simulated detector output based on the proposed response function agreed well with the experimental measurement. CONCLUSIONS: The performance of a spectral imaging system using energy-resolved photon-counting detectors is very dependent on the energy calibration of the detector. The proposed x-ray fluorescence technique offers an accurate and efficient way to calibrate the energy response of a photon-counting detector.
PURPOSE: To investigate the feasibility of characterizing a Si strip photon-counting detector using x-ray fluorescence. METHODS: X-ray fluorescence was generated by using a pencil beam from a tungsten anode x-ray tube with 2 mm Al filtration. Spectra were acquired at 90° from the primary beam direction with an energy-resolved photon-counting detector based on an edge illuminated Si strip detector. The distances from the source to target and the target to detector were approximately 19 and 11 cm, respectively. Four different materials, containing silver (Ag), iodine (I), barium (Ba), and gadolinium (Gd), were placed in small plastic containers with a diameter of approximately 0.7 cm for x-ray fluorescence measurements. Linear regression analysis was performed to derive the gain and offset values for the correlation between the measured fluorescence peak center and the known fluorescence energies. The energy resolutions and charge-sharing fractions were also obtained from analytical fittings of the recorded fluorescence spectra. An analytical model, which employed four parameters that can be determined from the fluorescence calibration, was used to estimate the detector response function. RESULTS: Strong fluorescence signals of all four target materials were recorded with the investigated geometry for the Si strip detector. The average gain and offset of all pixels for detector energy calibration were determined to be 6.95 mV/keV and -66.33 mV, respectively. The detector's energy resolution remained at approximately 2.7 keV for low energies, and increased slightly at 45 keV. The average charge-sharing fraction was estimated to be 36% within the investigated energy range of 20-45 keV. The simulated detector output based on the proposed response function agreed well with the experimental measurement. CONCLUSIONS: The performance of a spectral imaging system using energy-resolved photon-counting detectors is very dependent on the energy calibration of the detector. The proposed x-ray fluorescence technique offers an accurate and efficient way to calibrate the energy response of a photon-counting detector.
Authors: Dipanjan Pan; Ewald Roessl; Jens-Peter Schlomka; Shelton D Caruthers; Angana Senpan; Mike J Scott; John S Allen; Huiying Zhang; Grace Hu; Patrick J Gaffney; Eric T Choi; Volker Rasche; Samuel A Wickline; Roland Proksa; Gregory M Lanza Journal: Angew Chem Int Ed Engl Date: 2010-12-10 Impact factor: 15.336
Authors: J P Schlomka; E Roessl; R Dorscheid; S Dill; G Martens; T Istel; C Bäumer; C Herrmann; R Steadman; G Zeitler; A Livne; R Proksa Journal: Phys Med Biol Date: 2008-07-08 Impact factor: 3.609
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Authors: X Wang; D Meier; S Mikkelsen; G E Maehlum; D J Wagenaar; B M W Tsui; B E Patt; E C Frey Journal: Phys Med Biol Date: 2011-04-05 Impact factor: 3.609
Authors: David P Cormode; Ewald Roessl; Axel Thran; Torjus Skajaa; Ronald E Gordon; Jens-Peter Schlomka; Valentin Fuster; Edward A Fisher; Willem J M Mulder; Roland Proksa; Zahi A Fayad Journal: Radiology Date: 2010-07-28 Impact factor: 11.105
Authors: Ehsan Abadi; William P Segars; Benjamin M W Tsui; Paul E Kinahan; Nick Bottenus; Alejandro F Frangi; Andrew Maidment; Joseph Lo; Ehsan Samei Journal: J Med Imaging (Bellingham) Date: 2020-04-11