Portable Blood Flow-Imaging Watch Observing On the Move

Researchers have devised a compact version of photoacoustic imaging systems, offering a detailed view into the body, previously hindered by their bulky size. The miniaturized version fits into a watch, with its hardware housed in a backpack of comparable weight to an average five-month-old baby. This non-invasive device provides an effective means of assessing cardiac function.

In simple terms, photoacoustic imaging operates as follows: Initially, an object absorbs light, such as laser pulses, converting the absorbed optical energy into heat and causing a temperature increase. Subsequently, thermoelastic expansion leads to the emission of detectable sound waves. Unlike ultrasound imaging, which primarily identifies anatomy, photoacoustic imaging provides higher-resolution functional and structural images.

Advanced Applications of Photoacoustic Imaging

Due to its ability to penetrate tissues up to a depth of 2-3 cm (0.8-1.2 in), photoacoustic imaging has been utilized for scanning blood vessels, estimating blood oxygenation levels (oxygen saturation), and diagnosing skin conditions and cancer. Researchers from the Southern University of Science and Technology (SUSTech) in China have developed a compact photoacoustic imaging device that can fit inside a watch.

Lei Xi, the corresponding author of the study detailing the researchers’ new system, stated, “Although photoacoustic imaging is highly sensitive to changes in hemodynamics, challenges in miniaturizing and optimizing the imaging interface have hindered the advancement of wearable photoacoustic devices. To our knowledge, this is the first wearable photoacoustic device suitable for healthcare applications.”

Hemodynamics refers to the dynamics of blood flow. Monitoring hemodynamic parameters such as heart rate, blood pressure, and oxygen saturation provides insight into the efficiency of cardiac function.

The device developed by the researchers comprises a watch with an imaging interface, a handheld computer, and a backpack housing the laser and power supply (weighing 7 kg/15 lb). It is designed to allow the wearer unrestricted movement. The device’s adaptable laser focus enables imaging of multilayered structures like the skin, with a resolution of 8.7 µm adequate for imaging most small blood vessels within a maximum field of view of approximately 3 mm in diameter.

Field Testing of Photoacoustic Device

Volunteers utilized the photoacoustic device to evaluate its performance under various conditions, including walking and experiencing temporary blood flow blockage to the arm using a cuff. The tests confirmed that the system was functional, compact, and sufficiently stable to enable unrestricted movement.

Xi highlighted the potential of miniaturized wearable imaging systems, such as the one they’ve developed, for use in community health centers to diagnose diseases initially or continuously monitor blood circulation parameters in hospitals, offering valuable insights for treating various illnesses. Further improvements could enable these systems to aid in early detection of skin conditions like psoriasis and melanoma, as well as in analyzing burns.

The researchers are working on enhancing the system by creating a smaller laser source with a higher pulse repetition rate, which would improve compactness, reduce weight, and enhance safety and resolution, ultimately eliminating the need for the backpack.

Xi expressed confidence in the feasibility of developing a more advanced and intelligent photoacoustic watch, leveraging rapid advancements in modern laser diode and electronic information technologies, and eliminating the reliance on a backpack.

Additionally, the researchers aim to increase the device’s durability for strenuous physical activities like running and jumping. They also plan to incorporate more hemodynamic parameters, including qualitative assessments of blood vessel count and volume, to support early diagnosis of cancer and cardiovascular disease.

Read the original article on: New Atlas

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