Structure, functional, contrast-enhanced photoacoustic imaging of metastatic liver tumor in vivo

Metastatic tumors are challenging to diagnose and monitor treatment due to their unpredictable growth patterns and complex biology. Here, we demonstrate the application of photoacoustic computed tomography (PACT) for the detection and characterization of metastatic liver tumors. PACT enables simultaneous structural, functional, and contrast-enhanced imaging by exploiting the unique light absorption properties of biomolecules, allowing selective imaging through wavelength tuning. First, we observe the morphological changes in the metastatic liver tumor model in a non-invasive manner. Also, we visualize the heterogeneity of tumor tissues, achieving oxygen saturation distribution images. For models without significant structural changes, micelle-loaded IR780 nanoparticles were injected, leveraging the enhanced permeability and retention (EPR) effect to enhance tumor accumulation. These findings demonstrate the potential of PACT as a non-invasive, multiparametric tool for metastatic tumor detection, with promising future applications in clinical cancer diagnosis and treatment monitoring.