Radiation Exposure

Radiation is energy that travels in the form of waves or high-speed particles. We are exposed to radiation all the time from natural sources in the earth and from space. The x-rays used for making medical images and pictures are similar to light, but have a higher energy.

Your doctor has ordered a radiology test to get important information about your health. This information will help your doctor make an accurate diagnosis. Like most medical tests, radiology tests using x-ray radiation have some risks.

How Does Radiation Affect You?

The amount of radiation exposure that you receive from most radiology tests and procedures is small and the risk to you is low. Imaging Services works to keep your exposure to radiation to a minimum. You can help by discussing your concerns.

You should inform your radiologist or technologist about previous radiology tests that you have had, especially those tests that have been done in the past 12 months.

While most x-ray tests do not pose a critical risk to a developing baby, in some cases adverse effects are possible. It is important that you tell the radiologist or technologist if you think that you may be pregnant. They may decide to reschedule the test, take special precautions, or choose a different test.

If you are breastfeeding at the time of your test or procedure, you need to tell your radiologist or technologist. Some radioactive materials and contrast medication can pass into a mother’s breast milk. You may need to hold or stop breastfeeding for a period of time before or after your procedure.

Some imaging procedures and exams may require special preparation before you have the exam. You may be asked:

  • Not to eat or drink prior to your procedure
  • To have a driver present to take you home
  • To drink a contrast medication. There may be a period of time between drinking the contrast medication and having your exam
  • To wait after your exam for a period of time to recover before you go home

Inform your technologist of any allergies that you have. If you have a contrast allergy, you may be required to take medication prior to your exam. This medication will be prescribed by the physician who has ordered your exam.

An IV may be needed if your imaging exam requires the use of intravenous medication.

Additional testing that may be needed prior to your radiology exam:

  • Blood sugar level
  • Creatinine level
  • Pregnancy testing
  • PT/INR level 

Common Imaging/Radiology Exams

  • Angiography
  • CT scans(Computed Tomography)
  • DEXA (Bone Densitometry)
  • Fluoroscopy
  • IVP(Intravenous Pyelogram)
  • Mammography
  • MRI (Magnetic Resonance Imaging with no x-ray radiation)
  • Nuclear Medicine
  • Ultrasound (no x-ray radiation)
  • X-ray

Radiation Exposure Equivalents

Exam Effective Dose (mrem)

  • Abdominal x-ray: 140
  • Cerebral angiogram: 690
  • Cervical spine x-ray: 20
  • Chest x-ray: 10
  • DEXA: 6
  • IVP: 160
  • Mammogram: 40
  • Nuclear medicine cardiac study: 3,600

Risk Equivalent Values for Everyday Activities

Activity Effective Dose

  • One year of natural radiation for a typical American: 300
  • Plane flight from Los Angeles to Boston: 5
  • Rock climbing for 75 minutes: 10
  • Traveling 125 miles by motorcycle: 10