iodine-125
Sign in to saveAlso known as I-125, 125I
Iodine-125 (125I) is a radioisotope of iodine which has uses in biological assays, nuclear medicine imaging and in radiation therapy as brachytherapy to treat a number of conditions, including prostate cancer, uveal melanomas, and brain tumors. It is the second longest-lived radioisotope of iodine, after iodine-129.
Wikidata facts
- Instance of
- isotope of iodine
- Subclass of
- iodine
- Has part
- iodine
- Mass
- 124.904629333
Show 7 more facts
- atomic number
- 53
- neutron number
- 72
- half-life
- 59.407
- spin quantum number
- 2.5
- parity quantum number
- 1
- mass excess
- -88837.204
- binding energy
- 1056287.5
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Encyclopedic overview
6 sectionsContents
- Production
- Availability and purity
- Producers
- Decay properties
- See also
- Notes and references
Iodine-125 (125I) is a radioisotope of iodine which has uses in biological assays, nuclear medicine imaging and in radiation therapy as brachytherapy to treat a number of conditions, including prostate cancer, uveal melanomas, and brain tumors. It is the second longest-lived radioisotope of iodine, after iodine-129.
Its half-life is 59.392 days and it decays by electron capture to an excited state of tellurium-125. This state is not the metastable 125mTe, but a much shorter-lived excited state that decays either by (7% chance) emitting a gamma ray with energy of 35 keV, or more likely (93% chance), undergoing internally conversion and ejecting an electron (of lower energy than 35 keV). The resulting electron vacancy leads to emission of characteristic X-rays (27–32 keV) and Auger electrons (50 to 500 eV). In either case stable ground state 125Te is the product.
Excerpted from Wikipedia’s “iodine-125” article, available under the CC BY-SA 4.0 licence.