Development of a System Based on Photoacoustic Technology to Detect the Thickness of Cholesterol Oleate in the Blood Vessels of the Heart

As the composition of lipids in atherosclerosis is one of the main factors for indicating plaque vulnerability, a sensitive and accurate diagnostic method is desirable in the inspection of interiors of veins and arteries. In this regard, Intravascular Photoacoustic (IVPA) imaging modality is developed as a new and fast-growing medical diagnostic method. In this project, a novel analytical and signal processing methodology for increasing the axial resolution of a frequency-modulated photoacoustic imaging system is considered.

In this study, a photoacoustic imaging modality using an orthogonal correlated signal processing algorithm has been considered. The method uses a 1210 nm CW diode laser which modulates coherently-synchronously by pre-programmed and synthesized chirped signal.

The orthogonal correlated coherent photoacoustic imaging technique was developed as a novel method to increase the axial resolution of frequency-modulated photoacoustic system. The ultimate attainable axial resolution was ~ 20 um for cholesterol oleate.

Medical Photoacoustic imaging uses non-ionizing radiation to detect targets that harm living organisms in the human body. Different methods, in terms of modulation and signal processing, have been developed to render the chemical and topological properties of specific biological compounds. In this work, a novel frequency-modulated PA imaging based on an orthogonal correlation signal processing approach was developed. According to the experimental results and theoretical predictions, the present method was able to reach as low as ~20um axial resolution for cholesterol oleate.