Frequency domain photoacoustic and fluorescence microscopy

Area of Science:

• Biomedical optics
• Microscopy techniques
• Molecular imaging

Background:

• Photoacoustic microscopy (PAM) and fluorescence microscopy (FM) are powerful imaging modalities.
• Simultaneous acquisition of both signals can provide complementary information for enhanced biological sample analysis.
• Current limitations include resolution and the need for advanced system designs.

Purpose of the Study:

• To demonstrate simultaneous frequency-domain optical-resolution photoacoustic and fluorescence microscopy (FD-OR-PAF-M).
• To achieve sub-micrometer lateral resolution in both imaging channels.
• To compare the complementary information obtained from PA and fluorescence images using a biological sample.

Main Methods:

• Implementation of a frequency-domain photoacoustic microscopy system integrated with a fluorescence microscopy setup.
• Utilized sinusoidal modulation for photoacoustic signal generation and detection.
• Employed a blood smear as a biological sample for simultaneous imaging and data acquisition.

Main Results:

• Achieved simultaneous FD-OR-PAF-M with sub-micrometer lateral resolution.
• Demonstrated that photoacoustic and fluorescence images provide complementary information from the blood smear.
• Compared the signal-to-noise ratios (SNRs) of frequency-domain sinusoidal modulation versus time-domain pulsed excitation theoretically.

Conclusions:

• Simultaneous FD-OR-PAF-M is a viable technique for high-resolution bioimaging.
• The complementary nature of PA and fluorescence signals enhances diagnostic capabilities.
• Theoretical comparison provides insights into optimal excitation strategies for microscopy.