We have developed a fast, wide field-of-view, simple-to-implement laser scanning photoacoustic microscopy (PAM) system that is capable of imaging of the whole rat brain in < 1s. The system utilizes galvo scanners and a novel scanning scheme, that can counter the trade off between imaging speed and scanning area. We performed in-vivo imaging of rat brain to demonstrate the imaging capability of the system.
Photoacoustic microscopy (PAM) has demonstrated a wide range of medical and biomedical applications by providing vascular information. Since the size of PAM images is usually extremely large, an efficient compression method can help in the storage and transportation of these images. We have implemented multiple signal compression methods in LabVIEW with a high compression ratio, and an execution time below the repetition rate of the pulsed laser. The qualitative and quantitative results of ex vivo vasculature imaging with and without compression showed nearidentical images with significantly smaller size.
Photoacoustic (PA) signal experiences excessive background noise when generated using cost-effective, low-energy laser diodes. A denoising technique is essential in this case. Averaging is a common approach to increase the Signal-to-Noise Ratio (SNR) of PA signals. This technique requires numbers of data acquisition in hundreds and thousands and hence, demands more hardware and time consuming at the same time. Here, an adaptive method based on Adaptive Line Enhancers (ALE) algorithm to improve the SNR of PA signals has been presented. Our results validate the feasibility of the usage of an adaptive method and also indicate excellent improvement in terms of increasing the SNR of the PA signals. Additionally, this proposed algorithm requires way less number of acquisitions as compared to the conventional averaging techniques that leads to faster PA image processing.
Photoacoustic tomography (PAT) is an emerging modality for imaging living biological tissue. Being label free, non-invasive, and having comparable resolution to ultrasound, PAT has many medical translations. This paper demonstrates our development of a low-cost 16 element transducer array for rapid imaging (1 frame per second) of biological samples. For the first time we demonstrate quality images obtained with a completely low-cost system. A rotatable platform houses our 16 equidistant Technisonic transducers, which is rotated 22.5° to acquire a full 360° field of view. We use Ekspla NL200 series Q-switched laser at 532 nm illumination wavelength with coupled optical fiber for overhead illumination. Our transducers send data to a National Instrument data acquisition system, triggered by the previously mentioned laser for efficient detection of photoacoustic signal. We have characterized this system through the imaging of complex optical absorbing lead phantoms. Thin lead has been imaged to demonstrate the spatial resolution of the system using the point spread function. Characterization of this system will allow us to move to ex-vivo imaging. We aim to develop this system as a platform for quality small animal functional brain imaging.