The human body is one of the most complicated biological systems on the planet. Modern technology has rapidly aided scientists in accomplishing their never-ending quest to discover the unknown. In some ways, acoustics is helping to lead this new frontier by using ultrasound to listen to light (quite literally) and see “under the hood” of our bodies! Read on to learn more about what is coming down the road.
Ultrasound imaging (ultrasonography) is a popular noninvasive imaging method that uses a small ultrasonic transducer to transmit high-frequency sound waves into someone’s body. Ultrasonography was developed in 1940 by the American acoustical physicist Floyd Firestone and was first used in human bodies in 1941 by Austrian neurologist Karl Theo Dussik. Ultrasonography’s sound waves bounce around the target organ or muscle, are recaptured by the same transducer, and then constructed into a real-time image using a computer interface. In its many years of use, it has had some incredible applications including providing the ability to see an unborn child, to help break up kidney stones, and to provide muscle therapy and rehabilitation, just to name a few.
Ultrasonography is useful but is currently being rivaled by Photoacoustic Imaging (PA). Dr. Lihong V. Wang from Washington University in St. Louis has developed this innovative technology, which introduces an ultra-short pulsed laser to produce ultrasound in soft tissue. In other words, a laser creates vibrations in the desired internal organ or muscle, which are then detected by a series of transducers. An image of the target organ or tissue is reconstructed that is far superior in resolution quality than prior forms of imaging. Being that sound is a form of vibration, this method actually relies on listening to the “sound” generated by “light.”
Photoacoustic Imaging does not require any physical contact and can penetrate deeper than any non-invasive variations. This is currently the only method that is capable of providing high resolution molecular images of organelles, cells, internal organs, and tissues. The most impressive part of PA is its applications, which are currently endless. It will allow for the screening and detection of cancer at a much earlier stage than previous imaging methods, and will not require investigative operations. Additionally, scientists can use PA to determine how new drugs and medicine respond in mice and eventually humans. Even as you’re reading this, scientists are using this tool to conduct research with mice to create 3D, high-resolution images of their brains. By understanding the brain of a mouse, they can better understand the human brain and make serious advances in treating all types of cognitive ailments. If you would like to see what photoacoustic imaging looks like in action check out this video!
While listening to light might sound farfetched, Dr. Wang has brought this new technology to the forefront and opened the gates for further innovation.