Aims and objectives
Dual-energy (DE) radiography is a technique that can remove specific anatomical noise from a radiograph and generate tissue-subtracted images.
Typically,
a trio of images is presented comprised of a standard digital radiography (DR) image,
a soft-tissue image –where the bone clutter has been removed,– and a bone image –where the soft tissue is not present.
Such a technique is of particular interest in chest radiography,
where the detection of lung nodules has been shown to be primarily limited by anatomical noise[1].
Here,
the use of...
Methods and materials
A prototype for a multi-energy X-ray detector was built,
consisting of three stacked sensitive layers that will each simultaneously generate a digital image and serve as a beam-hardening filter for the subsequent layer.
Each layer consisted of a scintillator-based flat-panel sensor.
DR images were reconstructed by summing all layers’ images,
while tissue-subtracted images were generated using logarithmic subtraction.
Unlike conventional single-shot detectors,
this design does not require the use a metal mid-filter.
Therefore,
it enables the potential for high dose efficiency while maintaining a good...
Results
The detector was successfully able to produce high-quality tissue-subtracted images of the anatomical chest phantom at clinical radiologic exposure levels.
The amount and uniformity of tissue subtraction,
as well as the resulting image noise,
was subjectively comparable to current commercial systems.
No type of image alignment artifacts was present in the images.
The generated DR images DQE measurements showed improvement of up to 20% across the spatial frequency spectrum over established single-layer devices.
This shows that this detector is capable of simultaneously producing tissue-subtracted images...
Conclusion
The presented multi-energy detector has clear advantages over both the established dual-shot techniques –i.e.
real-time operation,
portability,
absence of motion artifacts,
and easy integration into existing systems– and single-shot systems –namely,
higher dose efficiency,
and allowance for more complex algorithms.
This feasibility study shows that this type of design can generate tissue-subtracted images in a clinical setting,
and hence proves that these advantages can be delivered.
Moreover,
the DQE measurements show that this detector lives up to its promise of increased dose efficiency without the...
References
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