October 09, 2008 — Jesse T. Yen, assistant professor of biomedical engineering in the Viterbi School, has been awarded a three-year, $750,000 grant from the National Cancer Institute (NCI) to develop an improved ultrasound probe to detect prostate cancer.
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Jesse Yen will develop a novel and much improved 3-D ultrasound array for prostate cancer detection.
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Yen’s novel probe design will build on current, state-of-the-art technology by allowing physicians to acquire three-dimensional images of the prostate with little or no manipulation of the probe. Prostate imaging using the new device will improve visualization of the prostate and more precisely guide biopsies, brachytherapy, and other minimally invasive procedures.
“The key to this technology lies in creating a transducer array that can electronically scan a 3-D volume of tissue instead of a 2-D slice,” said Yen, an expert in 3-D ultrasonic imaging technology. “That would be a big improvement over the current technology, which can only image slices of tissue in two dimensions. The probe currently in use is also operated mechanically, which means the user must possess great skill in order to guide a biopsy needle along the scan plane.”
Prostate cancer is the second leading cause of cancer death among men, according to NCI, a branch of the National Institutes of Health (NIH). Since there is no known cure yet, early detection followed by proper treatment offers the greatest chance of survival. Physicians for the most part use digital rectal exams (DRE) and prostate-specific antigen (PSA) tests to screen and diagnose prostate cancer, and then follow up with transrectal ultrasound (TRUS) imaging, which is used to locate the cancerous lesions.
“TRUS alone is not considered an effective method of detecting prostate cancer,” Yen said, “but it’s used not only to confirm DRE and PSA results, but for visualizing the prostate and for guidance of biopsies, as well as other intervention therapies, such as brachytherapy and cryotherapy.”
Brachytherapy is a form of internal radiation therapy where radioactive seeds are delivered to the target site using an image-guided needle system; cryotherapy destroys diseased cells by applying an extremely cold liquid to the lesion.
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Yen's 3-D TRUS probe, which will be able to image a cylindrical volume of tissue.
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To develop the new 3-D probe, Yen will first perform computer modeling and simulations to help evaluate imaging performance according to industry standards. Next, he will investigate methods of manufacturing the probe. The instrument will feature a 4 cm x 4 cm 2-D array with over 65,000 elements and almost 1,200 active channels operating in the 5-to-10 MegaHertz range. Design of the high frequency array will allow the instrument to image a curvilinear (cylindrical) volume of tissue.
USC has been a world leader in the development of these large, 2-D array transducers for real-time 3-D ultrasound imaging. Biut the university is also home to the Ultrasonic Transducer Resource Center, which is the nation’s only NIH resource center for high frequency ultrasonic technology. These technologies are already used for medical diagnostic procedures in ophthalmology and dermatology.
After design and prototyping of the array, Yen will spend the final phase of the study performing imaging experiments to evaluate performance. Then, with the guidance of a radiologist, he will compare his results with a commercially available 2-D TRUS probe. If the results show a marked improvement over the current technology, a clinically viable device could be developed within a few years.
