What is radiolabeling?
AME Studies (Absorption, Metabolism and Excretion)
Radiolabeled studies are also known as AME studies (absorption, metabolism and excretion) because of what they measure.
In an AME study, the study drug is specially prepared to contain radiolabeled carbon or tritium (found in soil, rocks and air). Adding a low dose of radiation to the study drug does not change how the drug works but helps us to see how the drug appears in body fluids such as blood, urine and stool after it is given to you.
What do I need to know about radiolabeled studies?
- Exposure to radioactivity can be measured in units called millirem (mrem). The amount of environmental radiation exposure depends on a number of factors and will vary from place to place. For example, here in Madison, Wisconsin, where these AME studies take place, we know the background radiation level is 620 mrem/year.
- The Food and Drug Administration (FDA) sets limits as to the amount of radioactivity that a research subject can be exposed to on a per study basis and over a given year.
- Maximum whole-body radiation exposure is 5,000 mrem/year and 3,000 mrem/study. We have a mandatory three-month “washout period” (the length of time between completing one study and starting a new study) for AME studies at our clinic; however, each study may have their preferred washout period.
- Our team of doctors and scientists calculates how much radioactivity you would be exposed to during a study to ensure that you are exposed to limits much lower than what is set forth in the FDA regulations.
Common radioactivity myths
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Will I glow in the dark if I take a radioactive drug?
No—radioactivity is invisible to the naked eye.
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Will radioactivity make me grow a third arm?
Radioactivity at the doses we administer will not change your appearance. The doses we do administer do have the potential to cause birth defects when a developing child is exposed to large quantities. Therefore, we place very important birth control restrictions for each study to prevent any such events from occurring.
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Will I feel the radiation inside me?
No—the only thing you will feel are the standard study procedures such as discomfort from a blood draw.
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Am I a risk to friends and family once I return home?
The amount radioactivity we administer is so low that even if you leave right after your dose you would be considered safe to your friends, family and the environment.
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Will there be any lasting effects from the radiation?
The amount administered is so low that the exposure is much less than you would receive on an annual basis from your normal environment.
Bananas and AME studies:
Putting radioactivity exposure into perspective
Radiation is everywhere in the environment, including the foods we eat. For example, eating one banana exposes you to one-hundredth (0.01) of a millirem (mrem) of radioactivity due to the radioactive potassium that is naturally occurring in the fruit. Normal daily activities can expose you to radioactivity, so let’s take a look at different exposures in terms of bananas.
When you fly in an airplane, you are exposed to radioactivity in the atmosphere. The higher the altitude, the less shielding you will get from the atmosphere so the higher the exposure. Flying at an altitude of 33,000 ft for one hour, your radiation exposure is estimated to be approximately 0.1 mrem (or 10 bananas).
A routine dental X-ray will expose you to approximately 0.5 mrem of radioactivity (50 bananas).
The annual radiation exposure by living in Madison, Wisconsin, is 620 mrem/year (62,000 bananas). In comparison, the average exposure per AME study is 360 (360 bananas or just a bit more than 5 dental X-rays).
To put these exposures into perspective, acute radiation sickness would take a dose of approximately 100,000 mrem of radioactivity (10 million bananas).
The most radioactive place on earth? A smoker’s lungs. The annual exposure of radioactivity to a smoker’s lungs is approximately 16,000 mrem/year—the equivalent of eating 1.6 million bananas.
How do I start enrollment for an AME study?
Fill out a brief form and we'll follow up to see if you qualify for an AME study. Or you can call us directly at 866-429-3700.