How video game processors could save lives

Researchers in San Diego unveil CT reconstruction algorithm for GPU platforms that reduce radiation exposure by a factor of 10 or more.

Elizabeth Armstrong Moore
Elizabeth Armstrong Moore is based in Portland, Oregon, and has written for Wired, The Christian Science Monitor, and public radio. Her semi-obscure hobbies include climbing, billiards, board games that take up a lot of space, and piano.
Elizabeth Armstrong Moore
2 min read
Electronic Arts

Are you dreading upgrading your graphics processor yet again just so you can get lost in the alien-infested urban jungle of Crysis 2? Rest assured that the immersive power of these state-of-the-art video processors is now being used for more than just visual pleasure.

A new technique for processing X-rays appears to lower the radiation patients are exposed to during cone beam computed tomography (CBCT) scans by a factor of 10 or more, according to researchers at the University of California, San Diego.

The research is being presented this week at the American Association of Physicists in Medicine's 52nd annual meeting in Philadelphia.

Lead author Xun Jia, a UCSD postdoctoral fellow, based his team's work on recent advances in compressed sensing by developing a CT reconstruction algorithm for graphics processing unit platforms (GPU cards being used for 3D computer graphics, often in video games), thereby increasing computational efficiency to reconstruct a cone beam CT scan in just minutes.

Image-guided radiation therapy (IGRT), a state-of-the-art cancer treatment, relies on dozens and even hundreds of scans during radiation therapy to more precisely target tumors and minimize radiation to surrounding, healthy tissue. (It is a cruel irony that treating cancer can simultaneously increase one's risk of getting cancer.)

The team wanted to investigate ways to reduce this large, cumulative radiation dose, but tuning down the X-ray generator pulse rate, pulse duration, and/or current during a CT scan results in mathematically incomplete data that involves hours of processing.

Compared to the widely used scanning protocol of about 360 projections, Jia says this new processing method uses only 20 to 40 projections, each with lower radiation levels, resulting in 36 to 72 times less exposure over the course of the CT scan.

The reconstruction algorithm is only one piece of the puzzle for the UCSD researchers, whose larger goal is to develop a series of GPU-based low-dose technologies for CT scans.

"The most interesting and compelling possibilities of this technique are beyond cancer radiotherapy," says senior author Steve Jiang. "For each year's use of today's scanning technology, the resulting cancers could cause about 14,500 deaths. Our work, when extended from cancer radiotherapy to general diagnostic imaging, may provide a unique solution to solve this problem by reducing the CT dose per scan."