Photoacoustic imaging (PAI), based on the photoacoustic effect, is a noninvasive imaging modality which has several merits for imaging biological tissues, especially small blood vessels. 

Since new blood vessels are an important indicator of early-stage prostate cancer, PAI promises to be an optimal candidate for prostate cancer diagnosis. 

Researchers from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences designed a novel handheld PAI probe with better performance and low cost for prostate cancer screening. The study was published in IEEE Sensors Journal.  

In the proposed probe, the light was guided to the sample surface directly below the ultrasound transducer. With this design, the laser energy was utilized with higher efficiency, leading to high signal to noise ratio (SNR) and deep imaging penetration.  

Besides, by using a single optical fiber rather than fiber bundle, the efficiency of laser transmission and the flexibility of the probe for operation were enhanced.

The sensitivity of the probe was high due to the higher transmission efficiency of the single optical fiber as well as the optimal optical illumination design.  

Moreover, the research team, in collaboration with The Third Affiliated Hospital of Sun Yat-sen University, executed in vivo canine prostate experiment and ex vivo human prostate experiment.

The results showed that the proposed probe could achieve high light transmission and illumination efficiency, high SNR, large imaging depth, and wide field-of-view (FOV) with laser energy well below the American National Standards Institute (ANSI) safety limit. 

This study sheds light on early screening of prostate cancer and early preventive treatment of prostate tumor. 

Single fiber-based transrectal PAUS probe design (Image by SIAT)