Table 1.
Radiation Exposures from Natural Background
and Medical Sources
Natural background (annuel exposures)
Total
_
Roentgens
0.085 - 0.20
Gamma rays (from territorial
sources) and cosmic rays
O.1 (varies)
Potassium-40 (internal)
0.018 (varies)
Carbon-14
7001
Medical Exposures
Chest X-ray
(per exposure)
0.2
Back X-ray
(per exposure)
O.4
Photoflurogram (per exposure)
_
about 0.5 - 2.0
Gastro-intestinal series
about 30.
59.
c¢