Quantitative fluorescence tomography using a trimodality system: in vivo validation.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Optical Imaging

Background:

• Accurate quantification of fluorescence in biological tissues is challenging.
• Multimodality imaging offers complementary information for improved image reconstruction.
• Diffuse optical tomography (DOT) and x-ray computed tomography (XCT) provide optical property and anatomical data, respectively.

Purpose of the Study:

• To develop and validate a fully integrated trimodality fluorescence tomography (FT), diffuse optical tomography (DOT), and x-ray computed tomography (XCT) system.
• To enhance the quantitative accuracy of fluorescence concentration imaging in small animals.
• To demonstrate the necessity of combined functional and structural a priori information for accurate FT reconstruction.

Main Methods:

• Integration of FT, DOT, and XCT systems for simultaneous small animal imaging.
• Utilizing DOT-derived optical properties and XCT-derived anatomical information as a priori data for FT reconstruction.
• In vivo experiments on nude mice with a deep-seated fluorescence inclusion.

Main Results:

• Localization of a 2-mm fluorescence inclusion 8 mm deep was only possible with DOT data.
• Without structural information, recovered fluorophore concentration error was ~87% using only DOT.
• With both DOT and XCT a priori information, fluorophore concentration was recovered with <2% error.

Conclusions:

• A trimodality FT/DOT/XCT system enables accurate quantitative fluorescence imaging in small animals.
• Combining functional (DOT) and structural (XCT) a priori information is critical for precise FT reconstruction.
• This integrated approach significantly improves the localization and quantification of fluorescence in vivo.