Label-free thermoacoustic imaging of human blood vessels in vivo

Here, we demonstrate that thermoacoustic imaging (TAI) is able to image human blood vessels in vivo without the use of any contrast agent. By optimizing the polarization direction of the antenna used, the microwave energy deposition in blood vessels is significantly enhanced, allowing the in vivo acquisition of thermoacoustic vascular images. Specifically, the fore arms of two adult male volunteers were imaged, and the blood vessels 5.5 mm below the skin in the forearm were recovered by TAI in both cross- and sagittal sections. Ultrasound imaging was used to cross-validate the images of blood vessels thermoacoustically imaged. The results obtained suggest that TAI may have the potential to become a new tool for examining vascular diseases.