Guidance on Selection of Radiation Type

When You Are Given the Separate Doses For Named Radiations

CAUTION: If you are uncertain about how to select the radiation type, you should consult experts in radioactive decay and internal dosimetry models.

Photons

For each radionuclide separately, the energy range can be selected on the basis of the average energy of emitted photons.

1. E > 250 keV - Applies to decay of mixed fission or activation products and many common photon-emitting radionuclides including, for example, ⁵⁸Co, ⁶⁰Co, ⁶⁵Zn, ¹⁰⁶Ru+¹⁰⁶Rh, ¹³¹I, ¹³²I, ¹³³I, ¹³⁴Cs, and ¹³⁷Cs+^137mBa.
2. E = 30-250 keV - Radionuclides that emit photon energies in this range include, for example, ⁵⁷Co, ¹⁴⁴Ce+¹⁴⁴Pr decay products, ¹⁵⁵Eu, ²³⁵U, and ²⁴¹Am.
3. E < 30 keV - Radionuclides that emit photon energies in this range include, for example, ⁵⁵Fe, ⁵⁹Ni, ^93mNb, and ^103mRh.

Electrons

For each radionuclide separately, the energy range can be selected on the basis of the average energy of emitted electrons, including the continuous spectrum of beta particles or positrons and discrete internal conversion and Auger electrons.

1. E > 15 keV - Radionuclides that emit electrons with average energies in this range include, for example, ¹⁴C, ⁶⁰Co, ⁸⁹Sr, ⁹⁰Sr+⁹⁰Y, ¹³¹I, ¹³²I, ¹³³I, and ¹³⁷Cs.
2. E < 15 keV - Radionuclides that emit electrons with average energies in this range include, for example, ³H, ⁵¹Cr, ⁵⁵Fe, ⁵⁷Co, ⁶⁵Zn, ¹⁰⁷Pd, and ¹²⁵I. However, this energy range should not be selected when the radionuclide emits low-energy Auger electrons and the radionuclide is known to be incorporated into DNA; in these cases, assistance from experts in microdosimetry should be sought.

Alpha Particles

Select "alpha" in all cases.