[Accuracy Verification for Slice Sensitivity Profile Measurement Method by Averaging the Multiple Tilted Wires in...

Area of Science:

• Medical Imaging
• Computed Tomography (CT)
• Image Reconstruction

Background:

• The tilted-wire method is often considered unsuitable for slice sensitivity profile (SSP) measurements in helical CT scans.
• Accurate SSP assessment is crucial for quantitative analysis and image quality in CT imaging.

Purpose of the Study:

• To compare the accuracy of the tilted-wire averaging method against the conventional micro-coin method for SSP determination in helical CT.
• To evaluate the influence of the number of wires and their positioning on the accuracy of the tilted-wire method.

Main Methods:

• A 64-detector row CT scanner was used to acquire images of micro-coin and tilted-wire averaging phantoms.
• Phantoms were scanned at central and off-center positions, with varying X-ray tube starting points.
• Images were reconstructed with a slice thickness of 0.5 mm for analysis.

Main Results:

• The tilted-wire averaging method showed minimal relative errors (-1.98% to -0.56%) at the center compared to the micro-coin method.
• Off-center measurements revealed increasing relative errors (up to 10.25%) with greater distance from the center and fewer wires.
• Accuracy was maintained regardless of the number of wires at the center, but decreased with fewer wires at off-center locations.

Conclusions:

• The tilted-wire averaging method, utilizing four or more wires arranged at 90-degree intervals, provides accurate SSP measurements.
• This optimized tilted-wire approach offers a reliable alternative for SSP assessment in helical CT imaging.