Photoacoustic imaging a PDT response marker for monitoring vasculature changes

Photoacoustic imaging (PAI) is an evolving modality for studying and imaging tumor hypoxia. The exper-imental results from animals treated with ALA for Pre-PDT, Post-PDT, 4hr PDT, 24 hr PDT show a short-term increase in the BV followed by a strong decrease; however, no complete stasis. An alternate method is created by looking at the spatial and frequency domain histogram to observe the tumor vasculature. The images are represented in frequency domains by application of two-dimensional Fast Fourier Transform (FFT) on spatial domain images. The variations in acoustic impedance after Photodynamic Therapy (PDT) are studied. The photoacoustic signals implemented on tumor models indicated PDT influ-enced variations in the hemoglobin levels against different time periods and studied their outcome on the tumor necrosis.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Photoacoustic imaging is an evolving modality for studying and imaging tumor hypoxia. Experimental results show a short-term increase followed by a strong decrease in the tumor vasculature after Photodynamic Therapy (PDT), but no complete stasis. An alternate method is developed by analyzing the spatial and frequency domain histogram of the tumor vasculature using two-dimensional Fast Fourier Transform (FFT). The variations in acoustic impedance and hemoglobin levels after PDT are studied, and their impact on tumor necrosis is investigated.