OHSU

Radionuclide Info

The following are resources for the safe handling of radioactive materials at OHSU: 

 

Radioactive Decay Calculator - install here

Common radionuclides used at OHSU:


Tritium 3H

Physical Data:

  • Physical Half-Life:  12.35 years

  • Maximum Beta Energy:  0.019 MeV (100%)

  • Maximum Range of Beta in Air:  ≈ 4.7 mm (0.19 inch)

  • Detector to use: Liquid Scintillation Counter only.  (note:  3H cannot be detected with hand-held survey instruments).

Dosimetry:

  • Millicurie quantities of 3H do not present an external exposure hazard because the low-energy betas emitted cannot penetrate the outer dead layer of skin.

  • The ciritical organ for 3H uptake is the whole body water.

  • Tritiated water is eliminated with a ten-day biological half-life.  Increasing water intake may increase elimination rates.

  • No external dosimetry is required

CARBON-14    14C

Physical Data:

  • Physical Half-Life:  5730 years

  • Maximum Beta energy:  0.156 MeV (100%)

  • Maximum range of Beta in Air:  ≈ 22 cm (8.6 inches)

  • Detector to use:  pancake G-M

Dosimetry:

  • Millicurie quantities of 14C do not present a significant external exposure hazard because the low energy betas emitted barely penetrate the outer dead skin layer.

  • The critical organ for uptake of many 14C labeled compounds is the fat.  Most 14C labeled compounds are rapidly metabolized and the radionuclide is exhaled as  14CO2.  Some compounds and their metabolites are eliminated via the urine.

  • Biological half-lives vary from a few minutes to 35 days - ten days being a conservative value for most compounds.

  • No external dosimetry is required.

 

SODIUM-22       22Na

Physical Data:

  • Physical Half-Life:  2.6 years

  • Principle Radiation Emissions: 

    • Gamma:  1.275 MeV (100%)  0.511 MeV (180%)

    • Beta: 0.546 MeV (90%)

  • Half Value Layer for Lead Shielding = 10 mm (0.39 inches)

  • Unshielded Exposure Rate from 1 mCi Point Source at 1 cm = 11.8 R/Hr

  • Detector to use:  NaI scintillation detector

Dosimetry:

  • The whole body is the critical organ for intake of transportable compounds of 22Na

  • Sodium is eliminated from the body with a biological half-life of 11 Days.

  • Whole body and/or ring badges may be required for external monitoring, depending on the activity used.



PHOSPHORUS-32      32P

Physical Data:

  • Physical Half-Life:  14.29 Days

  • Maximum Beta Energy:  1.71 MeV (100%)

  • Maximum Range of Beta in Air:  ≈ 6 m (20 feet)

  • Maximum Range of Beta in Water:  ≈ 8 mm  (0.3 inch)

  • Detector to use:  

    • Best - pancake G-M

    • Acceptable - NaI scintillation detector

Dosimetry:

  • The high-energy beta emissions can present a substantial skin dose hazard depending on activity, frequency and duration of use. 

  • The bones is the critical organ for intake of transportable compounds of  32P  bones

  • Phosphorus metabolism is complex.  30% is rapidly eliminated from the body.  40% possesses a 19 day biological half-life, and the remaining 30% is reduced by radioactive decay. 

  • The lung and lower large intestine are the critical organs for inhalation and ingestion, respectively of non-transportable 32P compounds.

  • Ring badges are required for personnel handling 32P.

PHOSPHORUS- 33      33P

Physical Data:

  • Physical Half-life:  25.2 Days

  • Maximum Beta energy:  0.249 MeV (100%)

  • Maximum Range of Beta in Air:  ≈ 50 cm (19.7 inches)

  • Detector to use: pancake G-M

Dosimetry:

  • Millicurie quantities of 33P do not present a significant external exposure hazard because the low energy betas emitted barely penetrate gloves and the outer dead skin layer.

  • The bones are the critical organ for intake of transportable compounds of 33P.

  • Phosphorus metabolism is complex.  30% is rapidly eliminated from the body, 40% possesses a 19 day biological half-life, and the remaining 30% is reduced by radioactive decay.  The lungs and lower intestine are the critical organs for inhalation and ingestion, respectively, of non-transportable 33P compounds.

  • No external dosimetry is required.

 

SULFUR-35     35S  

Physical Data:

  • Physical Half-Life:  87.4 Days

  • Maximum Beta energy:  0.167 MeV (100%)

  • Maximum Range of Beta in Air:  ≈ 24 cm (9.6 inches)

  • Detector to use: pancake G-M

Dosimetry:

  • Millicurie quantities of 35S do not present a significant external exposure hazard since the low energy emissions barely penetrate the outer dead layer of skin.

  • The critical organ for 35S is the whole body.

  • The elimination rate of 35S depends on the chemical form.  Most 35S labeled compounds are eliminated via the urine.35S methionine used for metabolic labeling is volatile.  Vials should be opened in an operating fume hood.  Activated charcoal should be placed in incubators to reduce contamination.

  • No external dosimetry is required

CALCIUM-45     45Ca 

Physical Data:

  • Physical Half-Life:  163 Days

  • Maximum Beta Energy:  0.257 MeV (100%)

  • Maximum Range of Beta in Air:  ≈ 52 cm (20.5 inches)

  • Detector to use:  pancake G-M

Dosimetry:

  • Milicurie quantities of 45Ca do not present a significant external exposure hazard because the low energy betas emitted barely penetrate gloves and the outer dead layer of skin. 

  • The critical organ for the uptake of 45Ca is bones.No external dosimetry is required.



CHROMIUM-51      51Cr

Physical Data:

  • Physical Half-Life:  27.7 Days

  • Principle Radiation Emissions:

    • Gamma:  0.320 MeV (9.8%)

    • X-ray:  0.005 MeV (22.3%)

  • Auger Electrons:  0.004 MeV (66.9%)

  • Half Value Layer for Lead Shielding = 1.7 mm (0.067 inches)

  • Unshielded Exposure Rate from 1 mCi Point Source at 1 cm = 0.18 R/hr

  • Detector to use:  NaI scintillation detector

Dosimetry:

  • The lower large intestine is the critical organ for the intake of soluble 51Cr compounds and ingestion of insoluble compounds.

  • An uptake of chromium is slowly eliminated from the body equally via urine and feces with a biological half-life of 616 days.  The dose committed is reduced by the short physical half-life of 51Cr.

  • No external dosimetry is required.

IODINE-125       125I

Physical Data:

  • Physical Half-Life:  60 Days

  • Principle Radiation Emissions: 

    • Gamma 0.035 MeV (6.5%)

    • Ka X-rays 0.027 MeV (112.0%)

    • Kb X-rays 0.031 MeV (25.4%)

  • Unshielded Exposure Rate at 1 cm from 1 mCi Point Source = 1.4 R/hr

  • Half-value Layer for Lead Shielding = 0.02 mm (0.01 inch)

  • Detector to use:  NaI scintillation detector

Dosimetry:

  • The thyroid is the critical organ for 125I uptake.

  • Individual uptake and metabolism vary over a wide range.  The thyroid may be assumed to accumulate 30% of soluable radioiodine uptake to the body and retain iodine with a 138 day biological half-life. 

  • Personnel performing iodinations with NaI or Bolton Hunter reagent are required to have a baseline thyroid scan and follow-up scans within 72 hours of the iodination. 

  • All procedures must be performed in an operating fume hood. Due to its volatility, all vials of Na125I must be vented through a charcoal trap prior to opening.

  • No external dosimetry is required.