Radiation - How Much Am I Getting?  How Can I Lower It?

What Can I Do to Limit My Exposure?

The American College of Radiology recommends the following:

Patients should also keep a record of their X-ray history and before undergoing a scan, should ask their physician:

  • Why do I need this exam?
  • How will having this exam improve my health care?
  • Are there alternatives that do not use radiation which are equally as good (e.g.. MRI, ultrasound, etc.)
  • Ask, is this facility ACR accredited? (ensures that physician and staff meet education and training standards and that equipment is surveyed regularly by medical physicist to ensure that it is functioning properly)

To ensure that their child is receiving a safe and necessary CT scan, parents may wish to:

  1. Ask whether the scanning protocol has been optimized for the child’s weight and body type.
  2. Make sure the CT scan is absolutely necessary, especially if multiple CT scans are performed.

So How much Radiation Am I Getting?

We absorb radiation from a variety of sources. How much is too much? Experts say 3 mSv per year is probably OK for most of us; 20 mSv for those who must have medical tests.

RADIATION

AMOUNT*

CT scan, full body

10–12 mSv

CT scan, chest

7 mSv

CT scan, Coronary CTA

See notes below

In 12 patients with body mass index (BMI) below 25, scanned for coronary artery evaluation, the average effective dose was 4.6 mSv*.

In 16 patients with BMI between 25 and 40, scanned for coronary artery evaluation, the average effective dose was 6.4 mSv*. Source: GE Medical website

On our CT scanner, the dose for all coronary exams ranged from 4 to 10.3 mSv* (ave 5.5mSv*).

*Actual measurements

Cardiac Catheterization

Up to 22.7 mSv

Nuclear Stress Test - Technicium

9.4 mSv

Nuclear Stress Test - Thallium

40.7 mSv

CT scan, brain

2.0 mSv

CT scan, abdomen 

8 mSv

CT scan, abdomen (liver)

15 mSv

CT Scan, pelvis

6mSv

CT Scan, abdomen pelvis

14 mSv

CT scan, Chest abdomen Pelvis

18 mSv

CT Scan, Virtual Colonoscopy

10 mSv

Fluoro – GI

6 mSv

Fluoro – Small Bowel series

5 mSv

Fluoro – Barium Enema

8 mSv

Mammogram

0.4 mSv

PET, Whole body

14.1 mSv

X-ray of chest

0.1 mSv

X-ray of Abdomen

0.7 mSv

X-ray of Extremity

0.01 mSv

X-ray of Lower Back

1.5 mSv

DEXA (bone-density) scan

0.01–0.05 mSv

Dental X-ray (bitewing)

0.02 mSv
Natural background radiation (from sunlight, radon gas, etc.) from living in high-altitude cities (e.g., Denver, Salt Lake City)

6 mSv (per year)

Natural background radiation from living at sea level (e.g., Chicago)

3.1 mSv (per year)

High-mileage frequent flying (100,000–450,000 miles per year)

1–6.7 mSv

Single airplane flight, coast-to-coast

0.01–0.03 mSv

Tobacco products (amount for a smoker’s lungs from 20 cigarettes a day)  

53 mSv (per year) (source =NIH)

Dosage source: X-rayRisk.com

*mSv=milliSievert, the scientific unit of measurement for radiation dose. At high levels, radiation can mutate the structure (genetic components) of a body’s dividing or reproducing cells and increase cancer risks. Sources: American College of Radiology; Radiological Society of North America; American Association of Physical Medicine; The New England Journal of Medicine; University of California, San Francisco, Cancer Center.