A team of scientists led by Lihong Wang at Washington University have more than doubled the resolution capabilities of the world’s fastest receive-only camera.
Now, the camera can take pictures of laser pulses that last just trillionths of a second as they travel through the air.
The new capabilities, which are detailed in the June 30 edition of Optica, have broad implications for researchers studying neuron activity and could help researchers learn more about how the brain works.
The camera, ultimately a series of devices combined to capture raw data, was developed by a team of Washington University engineers led by Wang, the Gene K. Beare Distinguished Professor of Biomedical Engineering, with $4 million in grant money from the National Institutes of Health.
The camera uses a technique developed at Washington University’s School of Engineering and Applied Science called compressed ultrafast photography (CUP) and could have major implications for scientists and researchers looking to acquire images from outside of the universe to reactions within the body, Wang said....
Using a high-tech imaging method, a team of biomedical engineers at the School of Engineering & Applied Science at Washington University in St. Louis was able to see early-developing cancer cells deeper in tissue than ever before with the help of a novel protein from a bacterium.
Lihong Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering at the School of Engineering; Junjie Yao, PhD, a postdoctoral researcher in Wang’s lab, and a team of engineers found that by genetically modifying glioblastoma cancer cells to express BphP1 protein, derived from the rhodopsuedomonas palustris bacterium, they could clearly see tens to hundreds of live cancer cells as deep as 1 centimeter in tissue using photoacoustic tomography.
The work, published Nov. 9 in advanced online publication of Nature Methods, is the first to combine deep-penetration, high-resolution photoacoustic tomography with a reversibly switchable, non-fluorescent bacterial phytochrome....
The migration of photoacoustic (PA) imaging technology from bench top to bedside, long expected thanks to its potential as an alternative to MRI and CT scanning in early-stage cancer detection, continues to take shape.
Use of the technique in breast cancer screening has always been identified as a likely clinical success story – not least by PA pioneer Lihong Wang – as it could offer ways to improve upon the high levels of false-positive results or other uncertain conclusions that current testing methodologies can deliver.
Further proof of that suitability should come from a small-scale clinical trial carried out at the University of Florida, the initial findings of which have now been released. The study used a photoacoustic tomography (PAT) platform developed by the university and now licensed to a new company, Advanced fPAT Imaging Inc (AFPII).
Company CEO Michael Addley told Optics.org that the clinical trial had involved a modest group of between 20 and 25 patients. "This is a small proof-of-concept study, that has had amazing results," he said.
The trial used AFPII’s JBI-360 imaging system, a platform developed from the work of Huabei Jiang at the University of Florida and which employs a functional photoacoustic tomography – or fPAT – approach. In use, maps of total hemoglobin concentration (HbT) and oxygen saturation (O2%), two key indicators of the metabolic activity associated with cancerous and pre-cancerous tissues, are reconstructed using a finite element algorithm to give valuable information about tumor location and sizing....
A human skull, on average, is about 6.8 millimeters (0.3 inches) thick, or roughly the depth of the latest smartphone. Human skin, on the other hand, is about 2 to 3 millimeters (0.1 inches) deep, or about three grains of salt deep. While both of these dimensions are extremely thin, they present major hurdles for any kind of imaging with laser light.
Why? The photons in laser light scatter when they encounter biological tissue. Corralling tiny photons to obtain meaningful details about tissue has proven to be one of the most challenging problems laser researchers have faced to date.
However, researchers at Washington University in St. Louis (WUSTL) decided to eliminate the photon roundup completely and use scattering to their advantage. The result: an imaging technique that would peer right into a skull, penetrating tissue at depths up to 7 centimeters (about 2.8 inches).
The approach, which combines laser light and ultrasound, is based on the photoacoustic effect, a concept first discovered by Alexander Graham Bell in the 1880s. In his work, Bell discovered that the rapid interruption of a focused light beam produces sound.
To produce the photoacoustic effect, Bell focused a beam of light on a selenium block. He then rapidly interrupted the beam with a rotating slotted disk. He discovered that this activity produced sound waves. Bell showed that the photoacoustic effect depended on the absorption of light by the block, and the strength of the acoustic signal depended on how much light the material absorbed.
"We combine some very old physics with a modern imaging concept," said WUSTL researcher Lihong Wang, who pioneered the approach. Wang and his WUSTL colleagues were the first to describe functional photoacoustic tomography (PAT) and 3D photoacoustic microscopy (PAM). [Listening with Lasers: Hybrid Technique Sees Into Human Body ]
The two techniques follow the same basic principles: When the researchers shine a pulsed laser beam into biological tissue, the beam spreads out and generates a small, but rapid rise in temperature. This produces sound waves that are detected by conventional ultrasound transducers. Image reconstruction software converts the sound waves into high-resolution images....
Researchers have created the fastest imaging device of its type—a tool that may transform biomedicine, telecommunications, and more.
Strain as you might, some events happen too fast to perceive—the flap of a hummingbird’s wings, an atomic bomb’s instantaneous detonation, supersonic bullets carving a watermelon. Advances in optical technology have allowed humans to savor ephemera, extending visual perception beyond bodily bounds.
The latest innovation was announced on the cover of the scientific journal Nature in December. Lihong Wang, a professor of biomedical engineering at the University of Washington in St. Louis, and his team have developed a camera fast enough to image light as it’s propagating. The technique, called compressed ultrafast photography, can capture up to 100 billion frames per second—as much as 10,000 times faster than the next fastest camera of its type (single-shot, two dimensional, no extra illumination needed).
Wang and his team’s invention combines two well-known pieces of equipment: a streak camera (which takes a signal and spreads it sideways into a smear) and a digital micro-mirror device (the engine of many electronic projection displays). Together, the components are able to resolve images in two planes on the order tens of picoseconds. (A picosecond is one trillionth of a second.) Brian Pogue, an engineering professor at Dartmouth College and author of commentary accompanying the Nature paper, says he believes the device’s steep price could easily drop by an order of magnitude, to $10,000, if the streak camera finds a larger market....
In the Jan. 5 issue of Nature Communications, Wang, the Gene K. Beare Professor of Biomedical Engineering in the School of Engineering & Applied Science at Washington University in St. Louis, reveals for the first time a new technique that focuses diffuse light inside a dynamic scattering medium containing living tissue.
In addition, Wang and his team have improved the speed of optical focusing deep inside tissue by two orders of magnitude. This improvement in speed is an important step toward noninvasive optical imaging in deep tissue and photodynamic therapy.
In the new research, the team built on a technique it developed in 2010 to improve the focusing speed of time-reversed ultrasonically encoded (TRUE) optical focusing for applications in living tissue. To focus light, the engineers use a virtual internal guide star at the targeted location. By detecting the wavefront of light emitted from the guide star, they can determine an optimum phase pattern that allows scattered light moving along different paths to focus at the targeted location.
When light is shined into living biological tissue, breathing and blood flow changes the optical interference, or speckle pattern, which can cause previous methods to focus diffuse light inside scattering media to fail. Scientists have to act quickly to get a clear image.
The new TRUE technology combines two techniques: focused ultrasonic modulation and optical phase conjugation. Researchers use a type of mirror to record then time-reverse the ultrasound-modulated light emitted from the ultrasonic focus to achieve the best focus....
A team of biomedical engineers at Washington University in St. Louis, led by Lihong Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering, has developed the world’s fastest receive-only 2-D camera, a device that can capture events up to 100 billion frames per second.
That’s orders of magnitude faster than any current receive-only ultrafast imaging techniques, which are limited by on-chip storage and electronic readout speed to operations of about 10 million frames per second.
Using a technique developed at the School of Engineering & Applied Science called compressed ultrafast photography (CUP), Wang and his colleagues have made movies of the images they took with single laser shots of four physical phenomena: laser pulse reflection, refraction, faster-than light propagation of what is called non-information, and photon racing in two media. While it’s no day at the races, the images are entertaining, awe-inspiring and represent the opening of new vistas of scientific exploration.
The research appears in the Dec. 4, 2014, issue of Nature.
“For the first time, humans can see light pulses on the fly,” Wang said. “Because this technique advances the imaging frame rate by orders of magnitude, we now enter a new regime to open up new visions. Each new technique, especially one of a quantum leap forward, is always followed a number of new discoveries. It’s our hope that CUP will enable new discoveries in science — ones that we can’t even anticipate yet.”...
Lihong Wang, PhD, the Gene K. Beare Distinguished Professor of Biomedical Engineering in the School of Engineering & Applied Science at Washington University in St. Louis, has received a prestigious BRAIN Initiative Award from the National Institutes of Health (NIH).
Wang’s three-year, $2.7 million award, is one of 58 grants totaling $46 million announced Sept. 30 by Francis S. Collins, MD, PhD, director of the NIH, in Washington, D.C.
The award is part of the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, a national research effort launched by President Barack Obama last year to revolutionize the understanding of the human mind and uncover new ways to treat, prevent and cure brain disorders such as Alzheimer’s disease, schizophrenia, autism, epilepsy and traumatic brain injury.
With the new grants, more than 100 investigators in 15 states and several countries will work to develop new tools and technologies to understand neural circuit function and capture a dynamic view of the brain in action. These new tools and this deeper understanding will ultimately catalyze new treatments and cures for devastating brain disorders and diseases that are estimated by the World Health Organization to affect more than 1 billion people worldwide....
Biomedical engineer Lihong Wang, PhD, and researchers in his lab work with lasers used in photoacoustic imaging for early-cancer detection and a close look at biological tissue. But sometimes there are limitations to what they can do, and as engineers, they work to find a way around those limitations.
Wang, the Gene K. Beare Distinguished Professor of Biomedical Engineering in the School of Engineering & Applied Science at Washington University in St. Louis, and Junjie Yao, PhD, a postdoctoral research associate in Wang’s lab, found a unique and novel way to use an otherwise unwanted side effect of the lasers they use — the photo bleaching effect — to their advantage.
The results were published online Jan. 10 in Physical Review Letters.
The researchers use an optical microscopy method called photoacoustic microscopy to take an intensely close look at tissues. The laser beam is a mere 200 nanometers wide. However, the center of the laser beam is so strong that it bleaches the center of the tissue sample. When researchers pulse the laser beam on the tissue, the molecules no longer give signals packed with information....
Wang will receive the James B. Eads Award, which recognizes a distinguished individual for outstanding achievement in engineering or technology.
Wang and his lab were the founders of a type of medical imaging that gives physicians a new look at the body’s internal organs, publishing the first paper on the technique in 2003. Called functional photoacoustic tomography, the technique relies on light and sound to create detailed, color pictures of tumors deep inside the body and may eventually help doctors diagnose cancer earlier than is now possible and to more precisely monitor the effects of cancer treatment — all without the radiation involved in X-rays and CT scans or the expense of MRIs.
A leading researcher on new methods of cancer imaging, Wang has received more than 30 research grants as the principal investigator with a cumulative budget of more than $40 million. In 2013, Wang received a Transformative Research Award from the National Institutes of Health.
The Academy of Science of St. Louis aims to foster the advancement of science and encouragement of public interest in and understanding of the sciences. The awards will be given April 9 at the Chase Park Plaza Hotel...