Optical-resolution parallel ultraviolet photoacoustic microscopy for slide-free histology

Area of Science:

• Biomedical Optics
• Surgical Technology
• Medical Imaging

Background:

• Intraoperative imaging of slide-free specimens is vital for accurate tumor margin identification in oncology.
• Current high-resolution ultraviolet photoacoustic microscopy (UVPAM) lacks sufficient speed and depth of field for real-time surgical guidance.

Purpose of the Study:

• To enhance the imaging speed and depth of field of UVPAM for intraoperative slide-free fresh specimen analysis.
• To develop a parallel UVPAM (PUV-PAM) system capable of rapid, histology-like imaging during surgery.

Main Methods:

• Developed PUV-PAM utilizing simultaneous scanning of eight optical foci to increase imaging speed.
• Employed eight needle-shaped beams to achieve an extended depth of field for imaging irregular tissue surfaces.
• Utilized a 50-kilohertz laser to achieve high-resolution imaging.

Main Results:

• Achieved an imaging speed of 0.4 mm²/s (4.2 min/cm²) at 1.3-micrometer resolution.
• Demonstrated fast imaging of slide-free tissues with irregular surfaces due to extended depth of field.
• Successfully acquired histology-like images of fresh specimens.

Conclusions:

• PUV-PAM significantly improves UVPAM imaging speed, overcoming limitations of low laser repetition rates.
• The extended depth of field capability enables rapid imaging of challenging, uneven tissue surfaces.
• PUV-PAM shows promise for enabling rapid intraoperative photoacoustic histology and advancing ultrafast optical-resolution PAM.