Abstract
Optical coherence tomography is a promising biomedical imaging technique, which is widely used in ophthalmology and gastroenterology, etc. In recent years, there are several groups developing Fourier domain optical coherence tomography integrated with laser scanning photoacoustic microscopy since the Fourier domain optical coherence tomography and photoacoustic microscopy have the same scanning mechanism. However, in order to increase the field of view (FOV) of photoacoustic microscopy that it commonly uses an unfocused ultrasonic transducer. The signal-to-noise ratio (SNR) of unfocused ultrasonic transducer is poor and produces a spatial impulse response (SIR) effect, which can lead to deteriorate axial resolution and impede the use of the high frequency and broadband transducer required for functional imaging applications. In order to solve this problem, our previous study has developed a virtual point detector concept for the photoacoustic microscope system that it can increase the signal-to-noise ratio, reduce the space impulse response, and obtain enough scanning field of view at the same time. In this study, we build a spectral-domain optical coherence tomography (SD-OCT) integrated with virtual point detector concept based laser scanning optical-resolution photoacoustic microscopy (OR-PAM) to provide microscopic imaging with both optical scattering and absorption contrast in biological tissues. Currently, the integrated system can provide 7.81 μm lateral and 68.2 μm axial resolution for OR-PAM and 6.20 μm lateral and 15.8 μm axial resolution for SD-OCT. The SD-OCT has much better axial resolution than the OR-PAM so that in addition to complementary image contrast, the SD-OCT can complement the depth resolving capability of the OR-PAM.