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Radionuclide Dosimetric Data Sheets
Iodine-128
Summary data
General
Classification
Isotope: I-128
Atomic number (Z): 53
Mass number (A): 128
Neutron number (N): 75
Radioactive decay
Decay modes: β-, β+, Electron capture
Half-life: 24.99 [m]
Decay constant: 4.6228e-04 [1/s]
Daughters: Xe-128 (93.1%), Te-128 (6.9%)
Radioactive daughters: None
Dosimetric constants
Mean alpha energy: 0.0 [MeV]
Mean electron energy: 0.74631 [MeV]
Mean photon energy: 0.06762 [MeV]
Air kerma rate constant, Γ10: 2.851e-18 [Gy·m2/Bq·s]
Air kerma coefficient, Kair: 2.852e-18 [Gy·m2/Bq·s]
Equilibrium dose constant for weakly-penetrating radiations (α and/or
electrons), Δwp: 1.196e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for alphas, Δα: 0.000e+00
[Gy·kg/Bq·s]
Equilibrium dose constant for betas/electrons, Δβ-,β+,e-:
1.196e-13 [Gy·kg/Bq·s]
Equilibrium dose constant for photons, Δp: 1.083e-14
[Gy·kg/Bq·s]
Dose point kernels (plot)
Dose point kernel source: Graves, et al. Medical Physics. 2019 Nov.; 46(11):5284-5293.
Note: Bins are spaced every 0.1 mm until a radius of 10 cm, and every 1 mm until a radius of 2 m.
Download tabulated dose point kernel file here: www.mirdsoft.org/products/MIRDspecs/I-128 DPK.csv
Summary spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/I-128 Summary Spectrum.csv
Beta spectra (plot)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Download tabulated beta spectra file here: www.mirdsoft.org/products/MIRDspecs/I-128 Beta Spectrum.csv
Tabulated data
Summary spectra (table)
Spectra source: ICRP Publication 107: Nuclear Decay Data for Dosimetric Calculations. Ann. ICRP 2008, 38 (3).
Note: Radiations with yield < 0.01 are excluded from the table, but are available in the linked *.csv data.
Download tabulated summary spectra file here: www.mirdsoft.org/products/MIRDspecs/I-128 Summary Spectrum.csv
|
Energy [MeV] |
Yield [#/nt] if > 0.01 |
Radiation type |
|
1.36107e-05 |
8.852e-01 |
X-ray |
|
1.66174e-05 |
2.014e-02 |
X-ray |
|
2.71868e-02 |
1.486e-02 |
X-ray |
|
2.74652e-02 |
2.767e-02 |
X-ray |
|
4.42901e-01 |
1.262e-01 |
Gamma |
|
5.26557e-01 |
1.203e-02 |
Gamma |
|
4.06732e-01 |
1.501e-02 |
Beta |
|
6.33655e-01 |
1.157e-01 |
Beta |
|
8.31946e-01 |
8.002e-01 |
Beta |
|
2.29240e-05 |
4.325e-01 |
Auger electron |
|
2.49255e-05 |
1.445e-01 |
Auger electron |
|
1.21007e-04 |
4.979e-02 |
Auger electron |
|
4.49506e-04 |
1.113e-01 |
Auger electron |
|
3.08483e-03 |
4.370e-02 |
Auger electron |
|
3.67897e-03 |
1.237e-02 |
Auger electron |
Useful Links
Isotope decay characteristics are periodically updated as better measurements can be made - changes that may not be reflected on this page. Please see useful links:
National Nuclear Data Center (NNDC): https://www.nndc.bnl.gov/nudat3/mird/
International Atomic Energy Agency (IAEA) Livechart: https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html
Reference Links
ICRP Report 107: https://www.icrp.org/publication.asp?id=ICRP%20Publication%20107
Graves et al. Dose Point Kernels: https://doi.org/10.1002/mp.13789
MIRD Decay Schemes 2nd Edition: https://sites.snmmi.org/SNMMI-MAIN/iCore/Store/StoreLayouts/Item_Detail.aspx?iProductCode=0-932004-80-6
MIRDsoft MIRDspecs version 20250101 (www.mirdsoft.org)
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