Transurethral light delivery for prostate photoacoustic imaging

Area of Science:

• Biomedical Optics
• Medical Imaging
• Prostate Cancer Research

Background:

• Photoacoustic imaging (PAI) shows promise for prostate cancer detection and treatment.
• Current limitations include inadequate light delivery for deep visualization.
• Minimally invasive methods are needed for enhanced imaging of targets like tumors and brachytherapy seeds.

Purpose of the Study:

• To develop and evaluate a side-firing fiber for transurethral PAI of the prostate.
• To improve visualization of brachytherapy seeds and other targets within the prostate.
• To enhance prostate cancer detection and treatment strategies through advanced imaging.

Main Methods:

• A side-firing fiber prototype was constructed for transurethral PAI.
• A method for calculating laser fluence at the fiber tip was developed and validated.
• 3D Monte Carlo simulations were used to model light propagation.
• Imaging was performed on phantoms, ex vivo, and in vivo canine prostates.
• Conventional delay-and-sum and short-lag spatial coherence beamformers were compared.

Main Results:

• The side-firing fiber successfully imaged brachytherapy seeds at depths of 5-30 mm.
• Real-time imaging was achieved at 3-5 frames per second.
• Short-lag spatial coherence beamforming significantly improved and stabilized seed contrast (28-32 dB) compared to delay-and-sum (23-9 dB).
• Improved multitarget visualization was achieved with the new beamforming method.

Conclusions:

• The developed side-firing fiber offers a promising solution for deep light delivery in transurethral PAI.
• Advanced beamforming techniques enhance the visualization capabilities of PAI for prostate applications.
• These advancements hold potential to significantly improve prostate cancer detection and treatment.