Our colleagues at Caltech and USC Vascular Surgery and Neurosurgery, including Lihong Wang, Charles Liu, Tze Woei Tan, and Jonathan Russin, have unveiled a major leap in medical imaging. Published in Nature Biomedical Engineering, the team introduces Hybrid Rotational Ultrasound and Photoacoustic Tomography (RUS-PAT).
Think of it as a high-speed, 3D panoramic camera for our internal anatomy. It bridges the gap between seeing the “house” (structural soft tissue) and the “plumbing” (the vascular network) in a single, elegant platform.
The Tech: RUST meets PAT
The system combines two powerful modalities that share the same detection hardware to keep things fast and cost-effective:
- RUST (Rotational Ultrasound Tomography): Uses a single-element transducer to transmit wide-field acoustic waves and a rotating arc of sensors to “listen,” creating a 3D structural map of soft tissue.
- PAT (Photoacoustic Tomography): Swaps the sound source for a light source—specifically a 1,064 nm laser—to visualize blood vessels with incredible detail without the need for contrast agents or ionizing radiation.
Why This Matters
Current imaging often forces us to choose between the high cost of MRI, the radiation of CT, or the limited “keyhole” view of handheld ultrasound. RUS-PAT breaks those barriers with:
- Speed: Only 10 seconds per imaging modality.
- Detail: Submillimeter isotropic resolution of approximately 400 µm.
- Scope: A large, 10-cm-diameter field of view.
Limb Preservation and the Diabetic Foot
For those of us dedicated to limb preservation, this is a potential game-changer. The manuscript highlights the system’s ability to detect both tissue and vascular abnormalities in patients with diabetic foot ulcers.
In a pilot case, the system successfully imaged a patient’s foot, clearly resolving the ulcerated region and the surrounding vascular network. By providing a high-resolution, 3D look at perfusion and morphology simultaneously, we can move toward more personalized management and earlier detection of complications that often lead to amputation.
Beyond the Foot
The researchers demonstrated the system’s versatility across several anatomical sites:
- Head: Revealed the scalp and cortical regions in a hemicraniectomy patient, showing clear boundaries between the scalp and brain tissue.
- Breast: Captured 3D internal structures and blood vessel distributions in healthy subjects, pointing toward a future in early cancer diagnosis.
- Hands: Mapped muscular tissue and complex vasculature, essential for evaluating injuries or peripheral vascular disease.
RUS-PAT isn’t just another scanner; it’s a safer, faster, and more comprehensive way to look “under the hood.”
Zhang, Y., Na, S., Russin, J. J., Sastry, K., Lin, L., Zheng, J., Luo, Y., Tong, X., An, Y., Hu, P., Maslov, K., Tan, T. W., Liu, C. Y., & Wang, L. V. (2026). Rotational ultrasound and photoacoustic tomography of the human body. Nature Biomedical Engineering. https://doi.org/10.1038/s41551-025-01603-5
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