First, some background
Nuclear magnetic resonance imaging (MRI) is a technique that scientists can use for medical research. It visualizes the distribution of specific atoms in the body. Most of the time MRI maps the hydrogen atoms in the body, which can reveal various abnormalities.
In one hot area of MRI research, scientists are developing ways to map out other atoms in the body besides hydrogen. For example, MagLab researchers have been improving techniques for targeting sodium, which can be used to show how brain tumors respond to chemotherapy.
What is the finding?
This research resulted in an important first: The first time that MRI has been used to see oxygen in a living brain, resulting in a relatively clear image, using the MagLab’s 21.1 tesla NMR/MRI magnet. Specifically, it was used to locate a specific isotope of oxygen (oxygen-17,or 17O, also called enriched oxygen), which had been incorporated into glucose and injected into a living rat.
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons, which can result in different properties. Oxygen-16 is by far the most abundant oxygen isotope, but it can’t be detected using MRI. So scientists manufactured glucose (the form of sugar used by our cells) with 17O, which can be detected using MRI. They then injected it into rats that had cancerous brain tumors, which consume a lot of glucose.
When the researchers did MRI scans of the animals that searched for the 17O from the injected glucose, they confirmed its appearance in the rats’ brains, effectively identifying the location of the tumor.
Why is this important?
Currently, a technique called PET (positron emission tomography) is often used to detect brain tumors in humans. However, PET scans have several downsides: They’re costly, result in fairly fuzzy images and, because they require injecting patients with radioactive isotopes, can be risky.
This research demonstrates a new and safe alternative that features the advantages of high-resolution magnetic resonance imaging.
Who did the research?
Victor D. Schepkin1, Andreas Neubauer2, Christian Schuch3, Tilo Glaeser3, Michael Kievel3, Steven L. Ranner1, William W. Brey1, Shannon Helsper1 and Lothar Schad2
1MagLab/FSU; 2University of Heidelberg, Mannheim, Germany; 3NUKEM Isotopes, Alzenau, Germany;
Why did this research need the MagLab?
The efficiency of 17O MRI increases dramatically with high magnetic fields. A two times increase in the magnetic field gives a 16 times reduction of the MRI scan time.
With the MagLab’s unique 21.1 tesla NMR/MRI magnet, the MRI of 17O is possible with a record resolution of 1 mm3 in the rat head (see image). Also, experts at the MagLab developed the special instrumentation required for this work, a double-tuned 17O/1H in vivo probe.
Details for scientists
- View or download the expert-level Science Highlight, The first observation of 17O MRI in normal rat brains at 21.1 T
This research was funded by the following grant: G.S. Boebinger (NSF DMR-1157490);
For more information, contact Victor Schepkin.