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Proactive Disclosure
Safety Code 34. Radiation Protection and Safety for Industrial X-Ray Equipment
Appendix II - Recommended Dose Limits for Ionizing Radiation
In its 1990 Publication 60 (1), the International Commission on Radiological Protection (ICRP) recommended dose limits for ionizing radiation. The dose limits do not include medical and natural background ionizing radiation exposures and are indicated below.
Table 1. Effective dose limits
| Person |
Period |
Effective Dose (mSv) |
Radiation worker |
(a) One year |
(a) 20 (average)
50 (special circumstances) |
(b) 5- year period |
(b) 100 |
Pregnant radiation
worker § |
Remainder of pregnancy |
2 |
Public |
One year |
1 |
§ In the case of a female radiation worker who is pregnant, the fetus must be protected from radiation exposure for the remainder of the pregnancy once pregnancy has been diagnosed.
Table 2. Equivalent dose limits
| Tissue or Organ |
Person |
Period |
Equivalent
dose (mSv) |
Skin |
(a) Radiation worker |
One year |
500 |
(b) Public |
One year |
50 |
Lens of
the eye |
(a) Radiation worker |
One year |
150 |
(b) Public |
One year |
15 |
Hands and feet |
(a) Radiation worker |
One year |
500 |
(b) Public |
One year |
50 |
Table 3. Organ or tissue weighting factors
| Organ or Tissue |
Weighting Factor, wT |
Gonads (testes or ovaries) |
0.2 |
Red bone marrow |
0.12 |
Colon |
0.12 |
Lung |
0.12 |
Stomach |
0.12 |
Bladder |
0.05 |
Breast |
0.05 |
Liver |
0.05 |
Oesophagus |
0.05 |
Thyroid |
0.05 |
Skin |
0.01 |
Bone surface |
0.01 |
Remainder organs mean all organs
and tissues, excluding the twelve
listed above, and include: adrenals,
brain, upper large intestine, small
intestine, kidney, muscle, pancreas,
spleen, thymus and uterus |
0.05 |
Whole body |
1 |
In those rare cases in which one of these remainder organs receives an equivalent dose that exceeds the equivalent dose received by any one of the preceding 12 organs listed, a weighting factor of 0.025 shall be applied to that organ or tissue and a weighting factor of 0.025 shall be applied to the average equivalent dose received by the remainder organs and tissues.
Table 4. Radiation weighting factors
| Radiation type and energy |
Radiation weighting
factor, wR |
Photons, all energies |
1 |
Electrons and muons, all energies § |
1 |
Neutrons of energy < 10 keV |
5 |
Neutrons of energy 10 keV to 100 keV |
10 |
Neutrons of energy >100 keV to 2 MeV |
20 |
Neutrons of energy > 2 MeV to 20 MeV |
10 |
Neutrons of energy > 20 MeV |
5 |
Protons, other than recoil protons, of energy > 2 MeV |
5 |
Alpha particles, fission fragments, heavy nuclei |
20 |
§Refer to Table S- 1 in ICRP 1990 Publication 60 (1) for specific notes on radiation types and energy.
