Noise considerations in dual energy CT scanning

Area of Science:

• Medical Imaging
• Radiology
• Physics

Background:

• Dual energy CT scanning (tomochemistry) is a technique used to determine elemental composition of tissues.
• Two primary methods exist: the
• two crystal
• technique and the
• two kV
• technique.

Purpose of the Study:

• To compare the relative noise and precision of dual energy CT scanning techniques.
• To evaluate the impact of CT image noise on measurement precision for tissue densities.

Main Methods:

• Review of three common approaches for utilizing dual energy CT scan data.
• Construction of a theoretical formalism to analyze noise influence.
• Comparison of spectral data overlap and signal-to-noise ratios between techniques.

Main Results:

• The
• two crystal
• technique exhibits lower signal-to-noise ratio due to spectral data overlap.
• The
• two kV
• technique requires hard filtration, which was not previously appreciated.
• The
• two kV
• technique offers a lower radiation dose for a given x-ray tube heat load.

Conclusions:

• The
• two kV
• technique is superior to the
• two crystal
• technique in terms of signal-to-noise ratio and radiation dose.
• Hard filtration is essential for the high energy beam in the
• two kV
• technique.