Comparing Radiation Doses For Different Tests*
Imaging Test | Approximate Number of Chest X-Rays (PA) Needed to Get the Same Dose | Approximate Environmental Exposure Equivalent to the Dose† |
|---|---|---|
Chest x-ray (2 views PA and lateral [side] | 5 | 10 days |
Screening digital mammography (CC plus MLO each breast) | 14 | 34 days |
An x-ray series of the lumbar spine | 70 | 180 days |
CT of the head | 80–100 | 210–250 days |
CT of the abdomen or pelvis | 300–400 | 2–2.7 years |
Coronary artery angiography during cardiac catheterization | 350–750 | 2.3–4.9 years |
DEXA | 0.05 | 3 hours |
X-ray of the abdomen (AP view) | 30 | 60-80 days |
* These doses account for how much radiation is delivered and how susceptible the body part exposed to radiation is to radiation damage. | ||
† People are exposed constantly to low levels of naturally occurring radiation but the amount varies in different geographic locations. | ||
AP = anteroposterior (eg, front to back); CC = craniocaudal (eg, top to bottom); CT = computed tomography; DEXA = dual-energy x-ray absorptiometry; MLO = mediolateral oblique (eg, side view); PA = posteroanterior (eg, back to front). | ||