Comparison of Rhenium and Iodine as Contrast Agents in X-Ray Imaging

Area of Science:

• Medical Imaging
• Materials Science
• Radiology

Background:

• Iodine-based X-ray contrast agents (I-XCA) have limitations in high kVp X-rays due to iodine's low atomic number and K-edge.
• Rhenium (Re), a high atomic number element, presents an alternative for X-ray contrast enhancement, but its use in X-ray contrast agents (XCA) is underexplored.

Purpose of the Study:

• To compare image quality and absorbed dose between I-XCA and Re-XCA.
• To prepare and evaluate a rhenium-doped scaffold for radiopacity.

Main Methods:

• I-XCA and Re-XCA were imaged using micro-computed tomography (µCT) and digital radiography (50-120 kVp) and planar X-ray imaging (120-220 kVp).
• X-ray beam hardening was achieved using copper filters (0.1-1.6 mm).
• A rhenium-doped scaffold was fabricated via electrospinning, coated onto catheters, and imaged using µCT.

Main Results:

• Re-XCA demonstrated superior contrast-to-noise ratio (CNR) at >120 kVp compared to I-XCA.
• The CNR advantage of Re-XCA increased with thicker copper filters, showing up to 59.1% improvement at 120 kVp with a 1.6 mm filter.
• Rhenium-coated catheters became radiopaque, indicating potential for enhanced visualization during procedures.

Conclusions:

• Monte Carlo simulations suggest Re-XCA can reduce absorbed dose while maintaining high image quality in high kVp X-rays.
• Radiopaque catheters offer potential for improved contrast during catheterizations, enabling faster and more precise placement.
• Rhenium-based contrast agents represent a promising advancement in X-ray imaging technology.