Quantitative imaging of electron density and effective atomic number using phase contrast CT

Area of Science:

• Medical Imaging
• Materials Science
• Physics

Background:

• Single energy CT provides limited material information (x-ray linear attenuation coefficients).
• Dual-energy CT quantitatively determines electron density and effective atomic number but requires dual energy spectra.
• Material characterization is crucial for medical and industrial applications.

Purpose of the Study:

• To present a novel quantitative imaging method based on phase contrast CT as an alternative to dual-energy CT.
• To extract quantitative information on electron density and effective atomic number from a single X-ray energy spectrum.
• To validate the method using physical phantoms.

Main Methods:

• Utilized diffraction-grating-based phase contrast CT.
• Reconstructed images of linear attenuation and refractive index decrement from single projection data.
• Developed relationships to derive electron density and effective atomic number.

Main Results:

• Electron density was accurately determined from refractive index decrement via a linear relationship.
• Effective atomic number was explicitly derived using the ratio of linear attenuation to refractive index decrement.
• The method demonstrated quantitative material property extraction from a single energy spectrum.

Conclusions:

• The presented phase contrast CT method enables quantitative material separation using a single X-ray energy spectrum.
• This technique offers a viable alternative to dual-energy CT for material characterization.
• The method has potential applications in both medical and industrial fields.