Simultaneous iodine and barium imaging with photon-counting CT.

Area of Science:

• Medical Imaging
• Materials Science
• Physics

Background:

• Conventional computed tomography (CT) struggles to differentiate materials with close atomic numbers.
• Barium (Z=56) and iodine (Z=53) are contrast agents with similar atomic numbers, posing a challenge for conventional CT.
• Photon-counting computed tomography (PCCT) offers potential for improved material differentiation due to its energy-resolving capabilities.

Purpose of the Study:

• To evaluate the capability of PCCT for simultaneous imaging and differentiation of barium and iodine.
• To assess the accuracy of PCCT in quantifying these contrast agents.
• To compare the performance of K-edge decomposition techniques (subtraction and PCA) for material differentiation.

Main Methods:

• Experiments utilized a bench-top PCCT system with a cadmium zinc telluride detector.
• Phantoms and a biological sample with varying concentrations (1%-5%) of barium and iodine were imaged.
• Multi-energy CT images were acquired by tuning energy thresholds to K-edge absorption energies, followed by K-edge subtraction and principal component analysis (PCA).

Main Results:

• PCCT successfully differentiated and quantified barium and iodine in phantoms and a biological sample with high accuracy (R2≈1).
• Principal component analysis (PCA) demonstrated superior differentiation compared to K-edge subtraction, especially in the presence of calcium.
• The system accurately reconstructed concentrations, highlighting its potential for precise material quantification.

Conclusions:

• PCCT shows significant potential for reliable and detailed imaging, particularly for contrast agents with similar atomic numbers.
• The technology offers improved imaging quality over conventional CT for applications requiring precise material differentiation.
• PCCT is a promising tool for both clinical diagnostics and scientific research, enabling enhanced material characterization.