Molecular Imaging Using Light-Absorbing Imaging Agents and a Clinical Optical Breast Imaging System—a Phantom Study

Abstract

Purpose The aim of the study was to determine the feasibility of using a clinical optical breast scanner with molecular imaging strategies based on modulating light transmission. Procedures Different concentrations of single-walled carbon nanotubes (SWNT; 0.8–20.0 nM) and black hole quencher-3 (BHQ-3; 2.0–32.0 μM) were studied in specifically designed phantoms (200–1,570 mm3) with a clinical optical breast scanner using four wavelengths. Each phantom was placed in the scanner tank filled with optical matching medium. Background scans were compared to absorption scans, and reproducibility was assessed. Results All SWNT phantoms were detected at four wavelengths, with best results at 684 nm. Higher concentrations (≥8.0 μM) were needed for BHQ-3 detection, with the largest contrast at 684 nm. The optical absorption signal was dependent on phantom size and concentration. Reproducibility was excellent (intraclass correlation 0.93–0.98). Conclusion Nanomolar concentrations of SWNT and micromolar concentrations of BHQ-3 in phantoms were reproducibly detected, showing the potential of light absorbers, with appropriate targeting ligands, as molecular imaging agents for clinical optical breast imaging.

Estimation of detection limits of a clinical fluorescence optical mammography system for the near-infrared fluorophore IRDye800CW: phantom experiments

“…The SoftScan system (Advanced Research Technologies Inc., Canada) was used to visualize highly absorbing contrast agents. 32 Single-walled carbon nanotubes were visible in a concentration of 0.8 nM and a Black Hole Quencher was visible in a concentration of 8.0 μM in phantoms with a volume of 0.2 cm 3 . In phantom experiments with a frequency-domain handheld probe-based optical imager developed by the group of Godavarty, concentrations of ICG of 1.0 μM were detectible in small phantoms of 0.10 to 0.45 cm 3 at a depth of 2.5 cm, but large relative differences in phantom-to-background concentrations (up to 25:1) and high baseline concentrations of the fluorophore (1.0 μM) were required for detection.…”

Optical Imaging in Breast Cancer Diagnosis: The Next Evolution

“…The SoftScan system by Advanced Research Technologies Inc., is a system that requires slight breast compression but is able to generate tomographic images of the breast. Using this system, van de Ven concluded that the use of such contrast agents, at least in addition to a targeting ligand, would have a great potential in future optical breast cancer diagnosis [30]. …”

Diagnostic Optical Imaging of Breast Cancer: From Animal Models to First-in-Men Studies

“…Using this system, van de Ven performed a phantom study, testing contrast agents of different intensity. It was concluded that the use of such contrast agents, at best in addition to a targeting ligand, would have a great potential in future optical breast cancer diagnosis (van de Ven et al, 2011). Detectors for fluorescence signals can also be minimized and e.g.…”