Table 1.
Representative Applications of PAT
| Applications | Imaging contrast/principle | Measured information | PAT system | Selected ref |
|---|---|---|---|---|
| Cellular Imaging | Hemoglobin in red blood cells | RBC morphology, oxygen saturation, cell aggregation, stimulation-response | Ultra-high-frequency PAM | (54, 213, 214) |
| DNA/RNA in cell nuclei | Cell nuclei morphology, nuclear size and packing density in tumor margin assessment | Ultraviolet (UV)-PAM | (214–216) | |
| Cytochrome in mitochondria | Mitochondria morphology and interconnectivity | OR-PAM/PA nanoscopy | (2, 151) | |
| Nanoparticle labeled stem cells | Track stem cell (embryonic, mesenchymal, etc.) migration | Dual-mode ultrasound-PACT | (217–219) | |
| Stained seed cells in engineered scaffolds | Track cell seeding within and quantify porosity and degradation of bio-scaffold | OR-/AR-PAM | (33, 167, 220) | |
| Functional imaging | Oxy- and deoxy-hemoglobin | Map blood oxygenation of whole mouse cortex | MEMS OR-PAM | (15) |
| Photoacoustic thermal tagging | Measure slow blood flow in deep mouse brain | PACT | (17, 136) | |
| Grüneisen parameter | Measure the tissue temperature during thermal therapy | PACT | (152, 153, 156) | |
| Hemodynamic fluctuation | Map brain’s functional connectivity during resting state | PACT | (221–224) | |
| Molecular imaging | Nanoparticle, organic dyes, genetically encoded chromophores | Use exogenous contrast agents as the probes for tumor imaging and cancer staging | PACT | (42, 225, 226) |
| Cancer imaging | Circulating tumor cells | Count the circulating tumor cells in melanoma as an independent indication of metastasis | PA flow cytometry | (227–231) |
| Breast cancer | Estimate the breast tumor size based on the angiogenesis or labeled by nanoparticles | PA mammography | (232–239) | |
| Melanoma | Evaluate the volume, depth and thickness of melanoma and provide staging | PACT | (40, 41) | |
| Prostate cancer | Visualize prostate brachytherapy seeds, detect prostate cancer cells labelled by nanoparticles | PACT | (240–244) | |
| Surgery or treatment guidance | Sentinel lymph node (SLN) | Track the needle tip and map SLN location during biopsy | PACT | (226, 245, 246) |
| PA-guided surgery | Real-time guidance for endonasal surgery and minimally invasive fetal surgery | PACT integrated with surgical tools | (247–252) | |
| High-intensity focused ultrasound | Monitor temperature and blood oxygenation during HIFU ablation | PACT integrated with HIFU | (136, 253, 254) | |
| Photothermal therapy | Monitor the nanoparticle delivery during photothermal therapy | PACT | (255–257) |