Conical ring array detector for large depth of field photoacoustic macroscopy

Area of Science:

• Biomedical Optics
• Acoustic Imaging
• Medical Device Technology

Background:

• Photoacoustic microscopy and macroscopy (PAM) offer high resolution and sensitivity for imaging biological tissues.
• A key challenge in deep-tissue PAM is maintaining constant lateral resolution across a large depth of field.

Purpose of the Study:

• To develop and evaluate a new detector design for scanning photoacoustic macroscopy.
• To address the challenge of achieving constant lateral resolution over an extended depth of field in deep-tissue PAM.

Main Methods:

• A novel sensor array geometry was designed using simulation and fabricated with polyvinylidene fluoride (PVDF) concentric ring elements.
• A reconstruction algorithm incorporating dynamic focusing and coherence weighting was employed.
• Experimental measurements using manufactured phantoms were conducted to assess array performance.

Main Results:

• The developed sensor array achieved a constant axial resolution of 95 µm and lateral resolution of 285 µm.
• This resolution was maintained over a significant depth of field of 20 mm.
• The system demonstrated reduced artifacts compared to single-element conical sensors.

Conclusions:

• The novel detector design significantly improves resolution consistency in photoacoustic macroscopy.
• The 20 mm depth of field is relevant for imaging biological tissues up to their maximum imaging depth.
• This technology holds promise for imaging localized regions of interest within biological tissues.