Ultrasound-switchable fluorescence thermometry with dual detection channels using temperature-sensitive liposomes

Area of Science:

• Biomedical Engineering
• Optical Imaging
• Therapeutic Monitoring

Background:

• Accurate temperature measurements are vital for studying biological processes and metabolic activities.
• Existing thermometry methods may have limitations in noninvasive, high-resolution applications.
• Developing advanced techniques for localized temperature mapping is essential for biological research.

Purpose of the Study:

• To introduce and validate a novel noninvasive thermometry technique using two-color ultrasound-switchable fluorescence (USF).
• To enable local temperature mapping within biological samples using temperature-sensitive liposomes.
• To assess the accuracy and reliability of the USF thermometry method compared to established techniques.

Main Methods:

• Utilized a two-color ultrasound-switchable fluorescence (USF) approach for thermometry.
• Employed temperature-sensitive liposomes as nanoimaging agents for local temperature sensing.
• Analyzed temperature-dependent fluorescence emission and appearance times of characteristic temperatures.
• Employed a camera-based USF system with two detection channels and simultaneous IR thermography for validation.

Main Results:

• Identified four characteristic temperatures based on liposome fluorescence emission.
• Estimated local background temperature by analyzing dynamic USF signals.
• Achieved a high degree of accuracy, with a minimal difference of 0.38°C ± 0.27°C compared to IR thermography.
• Demonstrated reliable performance within the physiological temperature range of 36.48°C-40.14°C.

Conclusions:

• The two-color USF thermometry technique is a reliable and noninvasive method for temperature measurements.
• This technique offers excellent spatial and thermal resolution for localized temperature mapping.
• USF thermometry shows significant potential for applications in biological research and metabolic activity studies.