Researchers Working To Speed Up Low-Dose CT Image Reconstruction

Researchers at the University of Michigan are working to make low-dose CT scans a viable screening technique by speeding up the image reconstruction from 30 minutes or more to just five minutes.

In December 2013, the US Preventative Services Task Force recommended lung cancer screenings for everyone between ages 55 and 80 who has been a smoker within the past 15 years. Roughly 90% of lung cancer cases are related to smoking, and the health care costs are approximately $12 billion per year in the United States.

"It's known that a radiation dose can increase the risk of cancer, but nobody knows exactly how much," says Jeffrey Fessler, PhD, a professor of electrical and computer engineering who leads the project.

Fessler's team is investigating methods to reduce the dose from around 2 mSv to between 0.24 mSv and 0.4 mSv. The drawback is that the images taken at these low X-ray doses are not as crisp initially as higher-dose images.

At present, it takes 30 to 60 minutes to reconstruct the low-dose images for diagnosis. That is impractical when the scans themselves take just a few minutes. Fessler and his team aim to cut that processing time down to five minutes.

Fessler thinks that today's computers are fast enough for shorter processing times, but they need to work smarter. Collaborating with Thomas Wenisch, PhD, an associate professor of computer science and engineering at the university, the research team aims to speed up processing by taking advantage of multicore computing.

The team's plan is to develop new algorithms to process CT scans that divide the data among the processors, allowing each to handle a certain region, and then stitch the image back together at the end.

The team will work from a data set gathered in a previous study, from volunteer patients who agreed to be scanned twice—once at 20% radiation dose and once at 80% radiation dose. These matched scans will allow the team to compare their upgraded images with higher-quality images.

If successful, the work could help make low-dose CT scans the norm. This would also benefit patients who need CT scans for other reasons. Low doses are particularly important for suspected cancer cases because they require multiple scans, Fessler says. Physicians watch for suspicious tissue that grows between scans.

Source: University of Michigan