Researchers have successfully purified a highly concentrated, hyperpolarized form of krypton gas called Krypton-83 which can be used as a novel MRI contrast agent for pulmonary imaging
Magnetic resonance imaging, or MRI, is an imaging technique that uses magnetic forces and radio frequency waves to produce 3D images of internal body structures like organs or bone. Contrast agents provide a clearer and more detailed MRI image, and can be either injected into or inhaled in one breath by the patient. In practice, hyperpolarized noble gases like helium and xenon are used for pulmonary MRI imaging and when inhaled, can be held in the lungs and scanned to produce high-resolution images.
In a recent paper in PNAS, researchers from the University of Nottingham reported that they had created a highly concentrated hyperpolarized form of krypton gas called Krypton-83, using a simple and controlled combustion reaction approach. The nuclei of gases for MRI must be hyperpolarized, or aligned, so that their density is more than that of tissue, resulting in a stronger MRI signal. To create Krypton-83, Krypton gas was combined with hydrogen in a process called spin-exchange optical pumping, followed by oxygen exposure. Exposure of the krypton-hydrogen gas mixture to oxygen triggers a combustion reaction that results in the creation of highly concentrated, hyperpolarized krypton and a small amount of water vapour.
This is a huge breakthrough in MRI technology as krypton is difficult to maintain in a hyperpolarized state during the preparation process before the MRI scan. The creation of a highly concentrated form of krypton presents an alternative to existing gaseous contrast agents for clinical use in pulmonary MRI, and the technology described in this study can be applied to the creating gases like xenon in a cheaper and simpler fashion for clinical monitoring and imaging technologies.
Written by Fiona Wong, PhD