Single-pulse photoacoustic computed tomography provides complete cross-sectional images of small animal organs

Many small experimental animals, the most common of which are mice, are indispensable for new drug development, physiological, pathological and preclinical research. If we can better study the living conditions of these small animals, it will be more valuable for many studies, such as tumor development, drug delivery, and prognosis research. Let's follow the editor of Medical Electronics to learn about the relevant content.

Single-pulse photoacoustic computed tomography provides complete cross-sectional images of small animal organs

Researchers from Duke University and Washington University in St. Louis have developed a technique called single pulse photoacoustic computed tomography (SIP-PACT). This is a new combination of photoacoustic technology that provides amazingly high resolution and can achieve real-time tomography of living small animals. The new technology can observe what organs look like in vivo, blood flowing, nerves firing, and tumors growing. The research was published in Nature Biomedical Engineering.

Photoacoustic imaging, which uses light to induce cells to emit ultrasound waves, can now scan the entire body of a living mouse in just one minute. (Image credit: Duke University )

Previously, whole-body imaging of these animal models relied on classical non-optical methods, including magnetic resonance imaging (MRI), X-ray computed tomography (X-ray CT), positron emission tomography (PET) or single photon emission computed tomography (SPECT) and ultrasound tomography (UST). Although these techniques can provide deep penetration, they have various limitations. Taking MRI as an example, achieving microscopic resolution requires expensive high magnetic fields and long data acquisition times, ranging from seconds to minutes, which is too slow for dynamic studies. X-ray CT lacks functional contrast, and PET and SPECT have poor spatial resolution when used alone. In addition, X-ray CT, PET and SPECT deliver strong ionizing radiation, which is not suitable for whole-body use in living subjects.

The photoacoustic imaging technology we introduced today breaks the long-standing barriers to resolution and speed in whole-body imaging of small animals. The new technology quickly provides complete cross-sectional images of the internal tissues and organs of small animals.

Using new technology to perform photoacoustic imaging of the workings of the intestines in mice. (Image source: Duke University)

Traditional optical microscopy can show fast, high-resolution images of tissue absorption and emission of light, but light can only penetrate a few millimeters into tissue, severely limiting its application. Ultrasound can penetrate deep into tissue, but cannot read the chemical composition and optical information of tissue. SIP-PACT technology integrates photoacoustic imaging into one platform. The technology uses extremely short laser pulses to enter the tissue, which generates ultrasound waves due to tissue heating and expansion, and then the ultrasound transducer can detect these sound waves to render images.

Schematic diagram of the SIP-PACT technology principle (Source: Nature Biomedical Engineering)

This is a safe imaging technology that can currently achieve a depth of 5 cm and sub-millimeter resolution, while retaining the functionality of an optical microscope. The upgraded device can scan adult rats in cross-section at a frequency of 50 times per second and image the details of the inner workings of living organisms at a resolution of 120 microns.

The new technology tracks neuronal firing in the brains of living mice by measuring oxygen levels, similar to functional magnetic resonance imaging scans. (Image credit: Duke University)

"The panoramic effect provides information from all angles, so you don't miss any information from each laser emission," said the researcher. "You can watch the real-time operation of the body - the heart pumping, the arteries dilating, the operation of various tissues."

This imaging technique has great potential for clinical application, it is safe and does not rely on any injected contrast agent. Currently, this technique is suitable for preclinical research and will be a powerful aid for drug development and evaluation, as well as disease research and treatment prognosis.

The above is an introduction to the use of single-pulse photoacoustic computed tomography in medical electronics to provide complete cross-sectional images of small animal organs. If you want to know more related information, please pay more attention to eeworld. eeworld Electronic Engineering will provide you with more complete, detailed and updated information.