How Much Radiation Is Too Much?

We are constantly exposed to radiation. When we reheat pizza in the microwave, we absorb trace amounts of radiation. We also get it when we walk through medical detectors at the airport, or when we get X-rays at the dentist. But that radiation is rarely a reason to panic. There are some cases where you do need to protect yourself, but we can generally handle more radiation than we realize.

Radiation sickness is a real thing, but it’s not caused by things like X-rays and CT scans. It’s much more likely to happen after some sort of industrial or chemical accident. Here’s a few things worth knowing about radiation, including cases where some protection is warranted.

Radiation in Medical Settings

We get the most exposure to radiation in medical and dental offices. When a dental technician places a lead apron over your body before taking X-rays of your mouth, they’re not doing it because it’s fashionable. Lead aprons are there to protect your body. You’ll probably notice that in many cases, lab technicians are also wearing some sort of protective gear. They’re typically in the room for multiple X-rays a day, so it’s even more important that they have a layer of protection between themselves and the radiation.

You won’t get sick from a standard amount of X-rays or CT scans. You might, however, feel queasy from radiation treatment for something like cancer. Radiation is designed to kill the cancer cells, but it typically takes other cells along with it as collateral damage. Radiation treatment isn’t done on the whole body; instead, it’s focused on the part of the body that has the cancer. You don’t want to protect that part of your body from radiation treatment that’s supposed to cure a disease.

Radiation therapy is designed to wipe out cancer cells, but it can also slightly raise the risk of cancer. That may sound like a cruel irony, but most doctors will opt to treat that problem that does exist now rather than worry about the small chance that treatment will cause additional problems later. If your doctor recommends radiation therapy, you should ask about the risk of cancer. It’s not something to be taken lightly, but in most cases, the long-term benefits outweigh the long-term risks.

How Radiation Is Measured

Radiation dosage is measured in something called sieverts. According to a report from Reuters, the sievert unit “quantifies the amount of radiation absorbed by human tissues.” One sievert equals 1,000 millisieverts. In 2011, an earthquake caused a Japanese power plant to explode; in the wake of that disaster, hourly radiation levels reached a peak of 400 millisieverts an hour. That’s 20 times higher than the annual exposure rate for uranium miners.

But most of us don’t go around throwing out millisievert and sievert measurements, so let’s put those numbers in context. When a doctor takes a chest X-ray to look for signs of pneumonia, that means exposure to 0.02 millisieverts, which is very low. A dental X-ray is even less than that. Experts believe you’d have to be exposed to at least 100 millisieverts a year for your chances of cancer to go up. That’s a ridiculous amount of X-rays, and no one has that many cavities.

What about CT scans? You get more radiation in those. A CT scan of the chest offers an effective dose of seven millisieverts, while a CT scan of the abdomen comes with eight millisieverts. If you get a lot of CT scans, those numbers can start to add up. If you’re concerned, you should feel free to talk to your doctor. A good doctor will take time to discuss the issue and figure out if there are any viable alternatives.