Radiation in Small Doses

What is radiation contamination and how does it differ from radiation exposure?

When radioactive materials in liquid, gas, or powder form are not kept contained, they can transfer to other surfaces or can be carried in the air. When radioactive material is “loose” and comes to rest on something, that something is then said to be contaminated—there is now radioactive material on it. If the something is a countertop, we have countertop contamination. If the radioactive material gets on our skin, we have skin contamination. If it gets inside of us, we are internally contaminated.

We need to know the type of radioactive contamination to determine whether we are being exposed to that radiation. So now it goes back to the discussion of the type of radiation (alpha, beta, gamma) and the energy of that radiation. In general, gamma radiation will expose us if it is an external source, skin contamination, or inside of us. Alpha and beta particles will expose us if they are inside of us. Some high-energy beta particles can expose us if they are on our skin.

A big difference between contamination and exposure comes when we talk about certain devices, like x-ray machines, that expose us to radiation. In this case, we are not talking about a liquid, gas, or powder, so this type of exposure does not cause contamination. Sometimes people who have an x-ray exam performed wonder if they are radioactive afterward. To become radioactive, you would need to become contaminated (have radioactive materials actually deposited on you or inside of you) and the x-ray machine does not do that.

Can radiation exposure be safe?

Yes. Radiation exposure that leads to small radiation doses for our bodies is safe in the sense that there either is no effect or the effect is too small to observe. There has been no evidence of illness or increased cancer risk at small radiation doses that are similar to the amounts we receive from routine x-ray procedures, natural background radiation (excluding radon), or occupational exposure. Radiation exposure in a short period of time that leads to very large radiation doses to our body can cause health effects within months, days, or even sooner. We know from health effect studies that large radiation doses over a long period of time can lead to an increase in some diseases, like cancer.

What can too much radiation exposure do to me?

Cancer is usually the effect that comes to mind for most people when we talk about radiation exposure and dose, but there is much more than that to talk about, including at what doses we need to be concerned. Take a look at the section titled "Radiation & Me" to read more about potential health effects from radiation exposure.

If I am pregnant, should I just say no to any and all medical radiation exposure?

It isn’t necessary to say no to all medical exams that involve radiation. If the exam involves radiation exposure of your lower abdomen and you know you are pregnant, you need to discuss this with your health care provider. If your life is in jeopardy (maybe you were in a car accident and need an abdominal CT scan), the first consideration is to save your life. The amount of radiation dose you would receive from most procedures conducted to diagnose a medical condition is very unlikely to jeopardize the pregnancy.

Can the radioactive substance have hazards other than the radioactivity—like being poisonous?

Yes, it can. If the substance is hazardous to health anyway, the radioactive piece is an additional hazard on top of the hazard that would exist if the substance wasn’t radioactive. An example is uranium. The heavy metal alone can make you sick. Add the fact that it is radioactive and it means you are also being exposed to the radiation it emits. So, if a substance by itself is cause for concern, making it radioactive adds to the concern because it can now potentially make you sick in more than one way.