Time-Reversed Ultrasound

Ultrasound technology has evolved to view just about every area of the body but it still has its limitations in efficiently penetrate varying tissues, which has limited ultrasound’s ability to treat and image critical areas of the body such as the brain, liver, and heart.  But, time-reversed ultrasound is an emerging technology designed to improve the accuracy of both imaging and therapeutic ultrasound technology.

Time-reversal captures and records a sound wave.  The wave is then compressed and stored in a database, and then sent back in the opposite order it was received.  So, it is sent back to its exact origin but at a much higher power.  This allows it to be very accurate through multiple tissue layers while producing a highly focused sound wave that requires less power to generate.

Focused ultrasound as a therapy has been approved since 2004 for treatment for uterine fibroids.  Although highly successful in soft tissue applications, it has limited accuracy when passing through bone or open body cavities.  Transcranial focused ultrasound surgery, an emerging technology for treating brain tumors, has realized the benefits of time-reversal technology.  In fact, one study found that refocusing the ultrasonic beam at the target improved the error to lower than 0.7 mm.

I had asked Dr. Emad S. Ebbini, Ph.D., biomedical researcher and associate professor at the University of Minnesota in Minneapolis, Minn., about the applications of Time Reversal technology and he noted, “Overall, time-reversal acoustics will be used to improve ultrasound technology.  With the time-reversal technique, you can correct for tissue aberrations and refocus the ultrasound wave to make it more accurate.  This overcomes the problem when you focus ultrasound through different types of tissue,”

Ultrasound is an amazing technology; it provides excellent image quality while being safe to both the operator and patient.  This and new handheld technology are two primary factors in driving a market that is expected to reach $1.4 billion by 2014.  When time-reversal acoustics becomes available, ultrasound will play a much larger role in the therapy market.

James Laskaris, EE, BME
James Laskaris, EE, BME, Clinical Analyst — Mr. James Laskaris is a senior emerging technology analyst at MD Buyline and has been with the company since 1994. With over 30 years of experience in the healthcare field, Mr. Laskaris is the primary analyst of high-end OR technology. He also covers issues related to the legislative and reimbursement effect on healthcare and authors a bimonthly “Issues that Matter” publication. Mr. Laskaris received his biomedical engineering degree from Southern Illinois University. His work has been published in hfm Magazine, Radiology Manager and Healthcare Purchasing News.