A Single Sensor Dual-Modality Photoacoustic Fusion Imaging for Compensation of Light Fluence Variation

Objective: A photoacoustic signal is proportional to the product of the optical absorption coefficient and the local light fluence; quantitative photoacoustic measurements of the optical absorption coefficients, therefore, require an accurate compensation of optical fluence variation. Usually, an additional diffuse optical tomography is incorporated to estimate the light fluence variation, but it is often troubled with the bulky measurement system. On this note, we present a dual-modality photoacoustic fusion imaging method that is implemented with a normal photoacoustic imaging (PAI) device. Methods: A single piezoelectric transducer is employed to receive the photoacoustic waves and passive ultrasound (PU) waves simultaneously. Since the PU wave is generated by the backscattering and diffuse reflection photons, it has the capacity to facilitate diffuse reflectance (DR) imaging. We merged photoacoustic and DR imaging based on their dual-modality with a compensation of the optical fluence variation. Results: The absorption coefficient differences caused by the light fluence variation are reduced more than half with the proposed method, when comparing to the pure photoacoustic imaging. Conclusion: The dual-modality photoacoustic fusion imaging is able to correct the PAI errors caused by the optical fluence variation. Significance: The proposed method can be widely accepted by different PAI applications to compensate the light fluence variations without any additional required element.