Molecular imaging using light-absorbing imaging agents and a clinical optical breast imaging system--a phantom study

Area of Science:

• Biomedical optics
• Molecular imaging
• Nanotechnology

Background:

• Optical breast imaging offers a non-ionizing alternative for breast cancer detection.
• Molecular imaging strategies can enhance the sensitivity and specificity of optical breast scanners.
• Developing novel contrast agents is crucial for advancing optical breast imaging.

Purpose of the Study:

• To assess the feasibility of using a clinical optical breast scanner for molecular imaging.
• To evaluate the detection of single-walled carbon nanotubes (SWNT) and black hole quencher-3 (BHQ-3) as potential imaging agents.
• To determine the optimal conditions for detecting these agents using light transmission modulation.

Main Methods:

• Investigated SWNT (0.8-20.0 nM) and BHQ-3 (2.0-32.0 µM) in phantoms of varying sizes (200-1,570 mm³).
• Utilized a clinical optical breast scanner with four wavelengths and an optical matching medium.
• Assessed absorption signals, compared background scans, and evaluated detection reproducibility.

Main Results:

• SWNT phantoms were detected across all four wavelengths, with optimal results at 684 nm.
• BHQ-3 detection required higher concentrations (≥8.0 µM), showing maximum contrast at 684 nm.
• Optical absorption signal correlated with phantom size and concentration; excellent reproducibility (ICC 0.93-0.98) was achieved.

Conclusions:

• Nanomolar SWNT and micromolar BHQ-3 were reproducibly detected in phantoms.
• Light absorbers, particularly SWNT and BHQ-3, show promise as molecular imaging agents for clinical optical breast imaging.
• The study validates the potential of these agents when combined with appropriate targeting ligands.