Scientists at Colorado State Investigate Laser-Polarized Krypton Gas for Medical Imaging

Laser-polarized krypton gas could someday be used to provide physicians with a quick, non-invasive way to study lung diseases, according to new research conducted at Colorado State University that appears this week in the journal, "Proceedings of the National Academy of Sciences."

Scientists are in the very early stages of exploring krypton as a gas for use in medical imaging, largely because it’s one of the best gases for improving contrast in pictures of the respiratory system produced by magnetic resonance imaging or MRI, according to Thomas Meersmann, assistant professor at Colorado State University since 2000 and principal investigator on the project.

"Contrast is really what we’re looking for so pulmonary diseases become visible and may be diagnosed," Meersmann said. "Any kind of contrast you can introduce is valuable."

How it would work: Patients would breathe the laser-polarized krypton gas, which is a noble gas. A distinguishing characteristic of noble gases is that they have no harmful effects on living tissues. The laser polarization has no physiological side effects but strongly amplifies the magnetic resonance imaging signals and allows researchers to obtain MRI scans of the lungs. The laser-polarized krypton also helps to create heightened contrast and makes the potential problem areas stand out.

One challenge is keeping the gas from depolarizing quickly until the MRI scan is taken. The laser-induced polarization decays within tens of seconds, which has made krypton very difficult to work with, Meersmann said.

"On the positive side, krypton can give you a contrast that other techniques can’t give you," he said.

Laser-polarized helium and xenon, also noble gases, have been successfully tested in the past as agents for lung MRI, but Meersmann expects years of further research and development before the technique will reach its full potential. A major research effort is being made to obtain additional contrast that allows for more detailed medical diagnosis of pulmonary diseases. Laser-polarized krypton may provide the key to tackle the problem, in particular if used in conjunction with laser-polarized helium and xenon MRI.

Other authors on the paper released Monday include Galina Pavlovskaya, Zackary Cleveland and Karl Stupic from the chemistry department and Randall Basaraba from the microbiology, immunology and pathology department at Colorado State.

While testing so far has been on porous materials and in vitro lung samples, Meersmann is collaborating with Susan Kraft, associate professor of radiology at the Veterinary Teaching Hospital at Colorado State, on studies of animal patients with lung disease.

"Animals and people suffer from a number of acute and chronic lung diseases, including asthma, chronic obstructive pulmonary disease, bronchitis, cystic fibrosis and emphysema," Kraft said. "Currently, there are few imaging methods for studying these diseases. Radiography and CT scans allow us to see anatomy and certain aspects of lung pathology but provide no information about lung physiology.

"Dr. Meersmann’s work is particularly exciting because he has developed an entirely new MRI contrast agent," she said. "Compared to the other laser-polarized gases, contrast enhancement of lungs with Krypton-83 may provide not only ventilation images but also unique information about the chemical nature of the air-exchange surfaces of the lung."

"Proceedings of the National Academy of Sciences," established in 1914, is one of the world’s most-cited multidisciplinary scientific serials.