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Currently, there are four major medical imaging technologies in the clinic: X-ray computer tomography (X-CT), ultrasound scan imaging (US), positron emission tomography (PET), and magnetic resonance imaging (MRI). They have developed rapidly, but they all have their own disadvantages. Compared with the above four imaging methods, the photoacoustic imaging (PAI) technology based on the photoacoustic effect has been extensively researched. PAI combines the high-contrast advantages of pure optical imaging and the high resolution of pure ultrasound imaging, which can achieve deeper imaging of biological tissues, and is currently widely used in biological imaging. The research in this paper is the expansion of the depth of field of the PAI system. The basic principle of PAI is to irradiate the target tissue with a short pulse laser, to excite ultrasound. The light absorption distribution reflecting the internal structure of the target tissue is reconstructed from the sampled sound waves. Since it needs to focus the laser strongly, this will result in a small imaging depth of field. Many biological tissues (such as brain, abdomen, etc.) have curved surfaces. Due to the limited depth of field of the optical imaging system, the blood vessels in the imaging field of view may not be on the same focal plane. It is arduous to get all accurately focused blood vessel images. It is not conducive to the observation of changes in the structure and composition of blood vessels, which brings great inconvenience to related researchers. In order to solve this problem, this paper proposes a large depth of field and high-resolution three-dimensional photoacoustic information fusion technology suitable for PAI systems. In this paper, the virtual blood vessel data sets are used to simulate the three-dimensional data sets of blood vessels at different focal positions collected by the PAI system. Based on the visualization software Amira, the two sets of three-dimensional data are reconstructed and fused. The results demonstrate that the fused virtual blood vessel imaging structure shows a complete high-resolution structure in the entire field of view. The validity and reliability of the method are verified.
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