What Is the Radiation Dose in X-Ray Imaging?
X-ray imaging is a diagnostic tool used by many oncologists to confirm a cancer diagnosis, stage a tumor or determine if a tumor is responding well to treatment. During an X-ray exam, radiation is used to create pictures of the inside of the body. Since parts of the body absorb radiation at different rates—for example, bones absorb the most radiation while the lungs absorb the least—they show up as white, black or gray images. The more radiation that is absorbed, the whiter the image. That’s why bones show up as white while soft tissue is gray.
It’s common to be concerned about the amount of radiation in X-ray imaging. Anyone who undergoes an X-ray exam will have some radiation exposure, but it’s not enough to cause a medical concern in the large majority of cases. In fact, there’s no scientific evidence that X-ray imaging increases one’s risk of cancer.
Everyone is exposed to radiation daily; this is called background radiation. Radon gas in a home, cosmic rays from space and natural materials in our environment expose people to radiation every day. On average, Americans are exposed to radiation at a rate of 3 millisieverts (mSv) a year. Compare that to the mSv of a chest X-ray (0.1), which means 10 days of natural background radiation is equal to one of these diagnostic tests.
Radiation dose in X-ray imaging
The radiation dose in an X-ray exam varies depending on what part of the body is being tested. For example:
- Extremity X-rays – exposure of 0.001 mSv
- Chest X-rays – exposure of 0.1 mSv
- Mammograms – exposure of 0.4 mSv
- Spine X-ray – exposure of 1.5 mSv
- CT scan of the head – exposure of 2 mSv
- CT scan of the spine – exposure of 6 mSv
- CT scan of the chest – exposure of 7 mSv
- GI tract X-rays – exposure of 8 mSv
- CT scan of the abdomen and pelvis – exposure of 10 mSv
- PET/CT scan – exposure of 25 mSv
X-rays and other imaging tests at Moffitt Cancer Center
Moffitt Cancer Center offers state-of-the-art diagnostic imaging from licensed technologists and board-certified radiologists who have subspecialty training in a specific area of cancer. For example, breast imaging exams are interpreted by radiologists with fellowship training in breast imaging. This unparalleled level of expertise provides our patients with accurate results for even the most complex forms of cancer. Our radiologists work hand-in-hand with other members of our oncological team to discuss treatment plans, additional testing and other services, helping our patients achieve the best possible outcomes and quality of life.