Finding out you have a brain tumor is scary, but early diagnosis can be the key to successful treatment. C-11 methionine PET scans help detect brain tumors faster and more efficiently.
According to Martin Satter, PET molecular imaging research scientist for Kettering Health Network, Kettering Health Network is the only health network in the United States to use C-11 methionine for PET scans routinely for the diagnosis and treatment of brain tumors in adults.
What is C-11 methionine, and how is it used?
Methionine is required for normal growth and repair of body tissues. The body can’t produce this amino acid itself—instead, we get it through our diet. It is thus considered an essential amino acid.
As amino acids typically collect in brain tumors, having an accumulation of methionine can be an early sign of a developing brain tumor.
To monitor that process, scientists make a radioactive version of methionine, inject it in the bloodstream of the patient, and then take a PET scan of the brain. The man-made C-11 methionine mixes with the naturally occurring methionine, and specialists can see any accumulation in the images.
Carbon-11 is short-lived, so it is important to have a source on-site to make C-11 methionine for the PET scan. A machine called a cyclotron makes the radioactive carbon C-11. Highly specialized radiochemists then add it to the natural methionine molecule to make the radioactive PET drug.
Kettering Health Network has been performing PET scans with C-11 methionine since 1995. With the recent installation of a new, more powerful cyclotron in 2019, we can continue to offer this rare diagnostic tool.
Advantages to C-11 methionine PET scans
Using this unique scan, nuclear medicine physicians can see the extent of the tumor better and earlier than with an MRI or CT scan. PET scans allow physicians to see changes in the brain sooner, leading to an earlier and more accurate diagnosis.
“One of the great advantages of PET imaging is that it is based on looking at biochemical differences in the tumor or in the body tissue, versus CT or MRI that looks at anatomy and anatomical changes,” says Steve Matmuller, chief nuclear pharmacist at Kettering Health Network.
“With PET, we can see smaller changes before they manifest themselves in larger, more anatomical abnormalities that CT or MRI can pick up. That is part of the power of PET.”
The surgeon and radiation therapist then have an advantage, as they can then use precision tools of image-guided surgery and gamma knife to resect or irradiate the tumor.
Candidates for PET scans
Candidacy for C-11 methionine PET scans is determined by the tumor type—typically, this diagnostic scan is used to identify tumors that originate in the brain. According to neurosurgeon Dr. Raymond Poelstra, it can identify parts of the tumor that may be more aggressive.
C-11 methionine PET scans are also used for presumed stroke patients whose diagnostic scans don’t improve with time. No improvement can suggest there is a tumor present in the brain.
“This can help us differentiate if it is a stroke or a tumor,” Dr. Poelstra says. “Sometimes, there is still something showing on a repeat CT scan in people who are assumed to have had a stroke. If there is that suspicion that it is more than a stroke, you can use methionine and determine if it is actually a tumor.”
Following the PET Scan
The C-11 methionine used in a PET scan behaves identically to the methionine obtained through the human diet, so there are no side effects to this imaging.
“The body can’t tell any difference from our version and normal methionine,” Matmuller says.
After a patient has a C-11 methionine PET scan, Kettering Health Network’s unique neuro-oncology tumor board performs a full-scale diagnostic review of their images. This board of multi-specialists meets weekly to discuss and determine the optimal treatment plans for all patients with brain tumors.
C-11 methionine can be used in a PET scan to help effectively diagnose brain tumors.