Figure 4. Effect of PUT on a rabbit ear model in vivo and histological photographs of rabbit ear tissues.

(a,b) Examples of the blood perfusion maps measured by a PeriCam PSI System before and after PUT on a rabbit ear. The perfusion map clearly demonstrated diminished blood flow in the treated microvessels (white arrows) after the treatment. Scale bar: 1000 μm. (c) Averaged blood perfusion rate in the target microvessels before and after PUT treatment in 5 rabbits. **p < 0.01, ***p < 0.001. The applied ultrasound negative peak pressure was 0.45 MPa at 1 MHz with 10% duty cycle, and the laser fluence was 20 mJ/cm² at 584 nm. (d) H&E stain image of rabbit ear tissue without PUT treatment, showing a normal auricular microvessel with a monolayer of integrated endothelial cells, basement membrane, and vascular smooth muscle (scale bar: 50 μm). (e,f) H&E stain images of rabbit ear tissue immediately following and 7 days after PUT treatment (scale bar: 50 μm), respectively. The formation of fibrin clot (black arrow) within the lumen in an auricular vein can be noticed, while the surrounding cells outside the blood vessel are not damaged.