Article by Wayne Gillam, Photos by Ryan Hoover / UW ECE News
UW ECE Assistant Professor Sajjad Moazeni and graduate students in his lab are part of a multidisciplinary, multi-institutional research team developing a new, three-dimensional imaging system for early detection of lung cancer. Moazeni’s contribution to this work includes development of sophisticated silicon photonic microchips — integrated circuits that use both electrons and photons (light) to process information. Shown above, an example of a silicon photonic chip from Moazeni’s lab. Moazeni will be developing chips similar to this one for the imaging system.
UW ECE Assistant Professor Sajjad Moazeni and graduate students in his lab are part of a multidisciplinary, multi-institutional research team developing a new, three-dimensional imaging system for early detection of lung cancer. This disease is one of the most common cancers worldwide, and in the U.S., it accounts for one in five cancer deaths, according to the American Cancer Society, which notes that early detection is key to survival.
The probe at the tip of this first-of-its kind imaging system is tiny, about the size of a grain of rice. This compact size will enable the team to shrink the bronchoscope that surrounds the system, which is used to investigate the lungs. Moazeni estimates that this slender bronchoscope could be approximately 10 times smaller in diameter than what is currently in use in clinics today — providing unprecedented access to small bronchial tubes inside the lungs.
The research team is led by Professor Soner Sonmezoglu from Northeastern University. In addition to Sonmezoglu, Moazeni, and their graduate students, the team includes engineers and medical professionals from Johns Hopkins University and Massachusetts General Hospital.
Moazeni’s contribution to this work includes development of sophisticated silicon photonic microchips — integrated circuits that use both electrons and photons (light) to process information. These chips will convert, digitize, and process electrical and optical signals within the imaging system. His lab will also be working with optical fibers to connect the imaging system probe to an electronic controller outside the body.
“One of the major novelties in this work is that all the communication from the tip of the probe that sends the signal through this bronchoscope to the external unit is being done in the optical domain, using optical fibers,” Moazeni said. “We’ll use just a few fibers to enable a high-quality, high-signal readout from the probe tip.”
The project is funded by an award of up to $13.2 million from the United States government Advanced Research Projects Agency for Health, known as ARPA-H. This agency provides funding for research that aims to improve health outcomes across a wide range of patient populations, communities, diseases, and conditions. ARPA-H focuses on transformative ideas for health research breakthroughs and technological advancements.
Blending photoacoustic imaging and silicon photonics
UW ECE Assistant Professor Sajjad Moazeni
The width of bronchoscopes today is typically measured in centimeters, but the research team’s bronchoscope will have a diameter measured in millimeters, enabling the imaging system to navigate deep into the lungs for early cancer detection. The prototype the team is developing will use a disposable probe that is 1.5 millimeters in diameter and a reusable electronic controller connected by optical fibers. The device will be able to gather high-resolution, 3D images that convey functional and structural information about tumors inside the lungs and whether they are benign or malignant. In addition to being compact, the device will be low power to avoid overheating sensitive tissues in the body, and it will be capable of producing precise, clear images in real time as the bronchoscope navigates the lungs.
The imaging system will use a technique called “photoacoustic imaging” to differentiate between healthy and cancerous tissue. Photoacoustic imaging combines optical excitation of tissue using a laser with ultrasound detection to produce high definition, 3D images. It is a method that has been gaining popularity in recent years for detecting breast cancer, skin cancer, and other types of cancers as well.
“Photoacoustic imaging has a lot of advantages for cancerous tumor detection, but in clinics, it is usually done through bulky equipment that is outside the body,” Moazeni said. “Here, we are making the probe tiny, so it can fit into a bronchoscope small enough to get into the finest pathways inside the lungs.”
Moazeni will use a silicon photonic microchip to interface optical fibers with ultrasound detectors at the tip of the bronchoscope probe. Outside of the body, in the electronic controller, he is building a chip that will convert optical signals from the bronchoscope into electrical signals. This chip will have 500 optical receiver channels, which, if achieved, will be a world record. Moazeni, who is known for developing advanced silicon photonic microchips for data centers, noted the advantages of this technology for medical applications.
“This is still optical communication, but instead of being between two computer racks in a data center, it is between the probe tip and the external module,” he said. “It’s very exciting to see that the same type of advanced chip that can revolutionize data centers can also have some real impacts on biomedical devices.”
Looking forward to clinical applications
The five-year grant and support from ARPA-H will enable the team to produce a prototype that can be moved into rigorous testing, commercialization, and adoption by doctors and clinicians. Through Johns Hopkins University and Massachusetts General Hospital, the team will have access to many medical professionals, who will provide guidance and input along the way.
Moazeni noted that this 3D-imaging system could also prove to be useful for detecting other types of diseases deep inside the body, including ovarian, prostate, and bladder cancers.
“Photoacoustic imaging has been proven to be very effective for cancer diagnosis and treatment, but so far, it has limited clinical use because of the form factor — how difficult it is to make the system small and compact,” Moazeni said. “Our device will aid early detection of lung cancer, and it could have a lot of other applications as well. It’s a highly sensitive tumor detector that could fit not only into the lungs, but potentially the veins, arteries, and maybe even the brain. So, eventually, it could have a huge impact on diagnosis and treatment of many different types of cancer.”
Learn more about this research in this recent press release from Northeastern University. More information about UW ECE Assistant Professor Sajjad Moazeni is available on his website bio.