Ruthenium-106/Rhodium-106 - UW-L Brachy Course


Relevant historical data:

Ruthenium 106 - discovered in 1844 by Karl Klaus; named after the Latin word Ruthenia (Russia).
Rhodium 106 - discovered in 1803 by William Wollaston; name=Greek - rhodon (rose).
Lommatzsch and Vollmar introduced the use of Ruthenium 106 and Rhodium 106 eye plaques in 1966.

Chemical/Radioactive Composition:

Transition Metal-Group #8, Period# 5
Chemical Symbol: Ru
Atomic number (Z, # of protons)=44
Mass number (A, # of protons + neutrons)= 106
Ru-106 - Atomic mass=105.9; number of neutrons=62.
Rh-106 - Atomic mass=105.9; number of neutrons=61.

Energy Characteristics:

Average energy= 96.9Kev,

Ru-106 decays by beta emission with decay energy (.039MeV) to Rh-106.
Rh-106 decays by beta emission with decay energy (3.541 MeV) to Pd-106.

Exposure Rate Constant:

  • Rh-106 - 0.138158

  • Half-life Properties:

    Ru-106: Half Life is 373.59D; or 1.02 years;
    Rh-106: Half life is 29.9 seconds.

    Forms available for use:

    Ruthenium 106 - used in Platinum alloys;
    Rhodium 106 - used in coatings.

    HVL in lead:

    HVL in lead=Range max E= 1800mg/cm2
    HVL in water= 24mm


    Visual inspection, surface contamination, leakage, and dose-rate verification. The surface contamination test consists of a wet wipe test at moderate pressure. The certified energy dose-rate statements of the manufacturer are examined with a 1 mm(3) plastic scintillator for consistency.

    Used in formula/calculation:

    Calculation of radiation dose:Dose rate in mGy X depth in mm

    Uses in Radiation Oncology:

    Ru-106 is used to treat choroidal and ocular with the use of eye plaque or applicator.

    Treatment Planning:

    Dose calculation are typically done with tables provided by manufacturer.

    One other interesting fact:

    Ru-106 and its short-lived daughter Rh-106 contribute an important fraction of the residual radiation in reactor fuels a year following their use. Recovery of the unused fissionable material is made difficult because of the radiation hazard and the chemical similarity between Ruthenium and Platinum.


    "Ruthenium-106 Brachytherapy for Uveal Melanomas- Preliminary Results : A Single Institutional Experience." Rodrigo Souza Dias,Adelmo José Giordani,Clélia Maria Erwenne Accessed at on March 29,2008

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