Detection geometry of the EOS system. The strips’ projections point to the x-ray tube focal spot. Photons enter through a collimation slit and a window (not shown).
Fraction of total energy converted by each electromagnetic process for different absorbers, for spectra of 50 (RQA 3), 70 (RQA 5), 90 (RQA 7), and (RQA 9). , , and gases are thick at , and are 0.5 and thick, respectively. The attenuation data come from XCOM (Ref. 22).
Diagram of the EOS device with a virtual patient (Ref. 23). The x-ray tubes and detectors move together. The images are acquired from top to bottom (dashed arrows).
Human subject images taken simultaneously at with tubes set at (face) and (profile). Subject is wearing a geometric calibration vest. The denser and thicker pelvic region is noisier but the images are nevertheless valid for orthopedic planning or follow-up measurements.
Computed center of mass coordinates of a circular radio-opaque object for 16 consecutive images.
Detector response curve for . The linear fit was done with air kerma values less or equal to the limit indicated by the arrow.
(a) LSF and (b) MTF in the horizontal direction for the 50, 80, and beams.
(a) LSF and (b) MTF in the vertical direction for the 50, 80, and beams.
Typical NPS for the EOS system showing anisotropy and ripple artifacts in the vertical directions, computed from a flat-field image taken at , , and . Nonlinear display windowing was applied to magnified low frequency components.
NPS in the (a) vertical and (b) horizontal direction for . A polynomial was fitted to the highest exposure and scaled according to Eq. (8) to produce (dotted lines).
Noisy channels can produce vertical line artifacts in images, as shown by arrows here.
Noise level in function of exposure at . The linear fit zero intercept is 0.06.
DQE in the (a) vertical and (b) horizontal directions for the beam.
DQE behavior in function of beam energy in the (a) vertical and (b) horizontal directions, with corrections accounting for the detector’s window absorption.
If Characteristics of the beams used in this work. is the input fluence per air kerma and is the fraction of the exposure that goes through the detector’s entrance window.
MTF values for different beam qualities at the IEC mandatory frequencies.
The measured and corrected DQE values at the IEC mandatory frequencies.
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