Detective quantum efficiency of fluoroscopic systems: the case for a spatial-temporal approach (or, does the ideal observer have infinite patience?)

Cunningham, Ian; Moschandreou, Terry E.; Subotic, Varja

doi:10.1117/12.430871

Cited by 19 publications

(27 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11 To illustrate the effect of lag, the RQA9 beam quality was used to irradiate the flat panel detector for a duration of 4 seconds at an exposure of 71 µR/frame. A lead shield is initially placed outside the beam path between the x-ray tube and the detector, and is moving into the beam path at about 1.5 seconds after the start of the exposure.…”

Section: Detective Quantum Efficiency (Dqe) Estimatesmentioning

confidence: 99%

Progress in the development of a dedicated breast CT scanner

et al. 2004

View full text Add to dashboard Cite

A pendant-geometry, cone-beam breast CT scanner has been constructed and is undergoing thorough testing in our facility. The system is capable of acquiring 30 frames/sec in 2×2 binning mode (1024×768 pixels) using a flat panel detector coupled to a thallium-doped cesium iodide scintillator. The DQE of the detector system for RQA5 and RQA9x-ray beam qualities were computed, and the low frequency DQE values were 65% and 57% respectively at approximately 16 µR/frame. The results also shown that minor improvements in DQE are achieved for exposures greater than 16 µR/frame. It is expected that the scanner will be available for the imaging of human volunteers in the first half of 2004.

show abstract

Section: Detective Quantum Efficiency (Dqe) Estimatesmentioning

confidence: 99%

Progress in the development of a dedicated breast CT scanner

et al. 2004

View full text Add to dashboard Cite

show abstract

“…In the context of standardized DQE-measurement protocols and comparisons, it is important that these potential errors be well understood. In addition, metrics that depend on the MTF-squared integral ͑such as Wagner's bandwidth integral 19,20 or recent work on temporal MTF properties of fluoroscopic systems [21][22][23][24] ͒ are very sensitive to systematic biases and normalization errors in the MTF.…”

Section: Introductionmentioning

confidence: 99%

Normalization of the modulation transfer function: The open‐field approach

Friedman

Cunningham

2008

Medical Physics

View full text Add to dashboard Cite

The modulation transfer function (MTF) is widely used to describe the spatial resolution of x-ray imaging systems. The MTF is defined to have a zero-frequency value of unity, and it is common practice to ensure this by normalizing a measured MTF curve by the zero-frequency value. However, truncation of the line spread function (LSF) within a finite region of interest (ROI) results in spectral leakage and causes a reduction in the measured MTF zero-frequency value equal to the area of truncated LSF tails. Subsequent normalization by this value may result in inflated MTF values. We show that open-field normalization with the edge method produces accurate MTF values at all nonzero frequencies without need for further normalization by the zero-frequency value, regardless of ROI size. While both normalization techniques are equivalent for a sufficiently large ROI, a 5% inflation in MTF values was observed for a CsI-based flat-panel system when using a 10 cm ROI. Use of open-field normalization avoids potential inflation caused by zero-frequency normalization.

show abstract

“…The concept of SNR rate 2 has been discussed in detail in earlier papers. [9][10][11][12] For a related approach see the paper of Cunningham et al 13 Our purpose in this paper is mainly to clarify the relationship between SNR rate 2 and the results of the visual measurements: subjective threshold contrast determination, 2-AFC, and 16-AFC-tests. The variability of human observers in stating the threshold contrast must be taken into account in this comparison; therefore, this variability is also evaluated here.…”

Section: Introductionmentioning

confidence: 99%

How should low‐contrast detail detectability be measured in fluoroscopy?

Tapiovaara

Sandborg

2004

Medical Physics

View full text Add to dashboard Cite

The relationship and precision of four methods for measuring the low-contrast detail detectability in fluoroscopic imaging were studied. These included the physical measurement of the accumulation rate of the square of the signal-to-noise ratio (SNR(rate)2), two-alternative forced-choice (2-AFC) experiments, sixteen-alternative forced-choice (16-AFC) experiments and subjective determination of the threshold contrast. The precision and sensitivity of the threshold contrast measurement were seen to be modest in the constancy testing of fluoroscopic equipment: only large changes in system performance could be reliably detected by that method. The measurement of the SNR(rate)2 is suggested instead. The relationship between the results of the various methods were studied, and it was found that human performance can be related to SNR(rate)2 by introducing the concept of the effective image information integration time (t(eff)). When measured for an unlimited observation time, it depicts the saturation of human performance in detecting a static low-contrast detail in dynamic image noise. Here, t(eff) was found to be about 0.6 s in 2-AFC tests and 0.3 s in 16-AFC tests.

show abstract

Detective quantum efficiency of fluoroscopic systems: the case for a spatial-temporal approach (or, does the ideal observer have infinite patience?)

Cited by 19 publications

References 10 publications

Progress in the development of a dedicated breast CT scanner

Progress in the development of a dedicated breast CT scanner

Normalization of the modulation transfer function: The open‐field approach

How should low‐contrast detail detectability be measured in fluoroscopy?

Contact Info

Product

Resources

About