Single-impulse photoacoustic computed tomography (SIP-PACT) is commercially available through CalPACT/UPT. Imaging of small animals has played an indispensable role in preclinical research by providing high dimensional physiological, pathological, and phenotypic insights with clinical relevance. Yet pure optical imaging suffers from either shallow penetration (up to ~1–2 mm) or a poor depth-to-resolution ratio (~1/3), and non-optical techniques for whole-body or whole-brain imaging of small animals lack either spatiotemporal resolution or functional contrast. SIP-PACT mitigates these limitations by combining high spatiotemporal resolution (125-μm in-plane resolution, 50 μs / frame data acquisition and 50-Hz frame rate), deep penetration (48-mm cross-sectional width in vivo), anatomical, dynamical and functional contrasts, and full-view fidelity. SIP-PACT has imaged in vivo whole-body or whole brain dynamics of small animals in real time and obtained clear sub-organ anatomical and functional details. SIP-PACT has tracked unlabeled circulating melanoma cells and imaged the vasculature and functional connectivity of whole rat brains.
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Supplementary Video 1In vivo label-free PACT imaging of mouse internal organs. The scanning red line shows the corresponding elevational position of the cross-sectional image. The red box indicates the position of the close-up image. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. Stepping along the animal trunk with a step size of 0.08 mm, a total of 600 cross-sectional images were acquired, with a 25 mm by 30 mm cm field of view. | |
Supplementary Video 2In vivo label-free PACT imaging of mouse whole-body anatomy at a cross-section of the upper thoracic cavity, with contrast enhancement filtering described in Online Methods. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 3In vivo label-free PACT imaging of mouse whole-body anatomy at a cross-section of the lower thoracic cavity, with contrast enhancement filtering described in Online Methods. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 4In vivo label-free PACT imaging of mouse whole-body anatomy at a cross-section of the liver, with contrast enhancement filtering described in Online Methods. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 5In vivo label-free PACT imaging of mouse whole-body anatomy at a cross-section of the upper abdominal cavity, with contrast enhancement filtering described in Online Methods. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 6In vivo label-free PACT imaging of mouse whole-body anatomy at a cross-section of the lower abdominal cavity, with contrast enhancement filtering described in Online Methods. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 7In vivo PACT mouse liver cross-sectional images reconstructed from increasing angular coverage. Angle was gradually increased from 45 to 360 degrees. Reconstruction artifacts are significantly mitigated while angular coverage increases. | |
Supplementary Video 8Pulse wave induced cross-sectional area changes of two vertical arteries over time. The right panel co-plots the normalized cross-sectional areas of the two arteries and shows the relatively stable phase delay between them. | |
Supplementary Video 9In vivo label-free PACT imaging of mouse brain response to oxygen challenge. During the measurement, the pulse repetition rate was 10 Hz. The movie was created by down sampling at a ratio of 25:1. | |
Supplementary Video 10Lower abdominal cavity oxygenation response of a mouse during whole-body oxygen challenge. This cross section shows the spleen, cecum, intestine, and both kidneys. The bottom-right panel shows the change of the signal level averaged over the entire FOV. | |
Supplementary Video 11Label-free tracking of circulating melanoma tumor cells in the mouse brain in vivo. The light fluence on the animal skin was 8 mJ/cm2 at 680 nm, with a pulse repetition rate of 10 Hz. | |
Supplementary Video 12In vivo monitoring of dye perfusion in the mouse brain. The right panel shows the normalized change of the signal level averaged over the entire FOV. The dye solution (100 µL with 0.5% mass concentration) was injected through the carotid artery. The light fluence on the animal skin was 18 mJ/cm2 at 1064 nm, with a pulse repetition rate of 50 Hz. | |
Supplementary Video 13In vivo label-free PACT imaging of rat whole-body anatomy at a cross-section of lower abdominal cavity, with contrast enhancement filtering and adaptive gain compensation described in Online Methods. The entire cross-section (48 mm in width) is clearly visualized with high contrasts of rat internal organs. |
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