Radiation Safety
APPENDIX III: SPECIAL PRECAUTIONS FOR USE OF SPECIFIC NUCLIDES
There are many radionuclides used at UC. Common ones are 14C, 45Ca, 51Cr, 3H, 125I, 131I, 22Na, 32P, 33P, 35S, 99mTc and 201Tl. Information concerning these radionuclides follows. Many of these radionuclides require that special precautions be observed when using them. Some recommended precautions for widely used radionuclides are available in various Biological Effects of Ionizing Radiation (BEIR) reports, Chemical Rubber Company (CRC) Handbooks, and Material Safety Data Sheets (MSDS) available from radiochemical manufacturers. For further guidelines on the use of specific radiation sources, contact the RSOF at 558-4110.
*ALI = Annual Limit of Intake
14C
Radioactive Half-life: 5730 years
Mode of Decay: beta (maximum energy 156 keV)
Beta range in air: 25 cm
Beta range in water: 0.03 cm
Critical Organ: whole body or fat (depending on chemical form)
ALI: 2 millicuries
Dosimetry: urine bioassay
Shielding: none
Monitoring Methods: thin end window GM or pancake GM
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) If volatile, work only in a hood.
3) If possible internal exposure perform urine bioassay.
4) Monitor with a GM survey meter after each use.
45Ca
Radioactive Half-life: 163 days
Mode of Decay: beta (maximum energy 257 keV)
Beta range in air: 52 cm
Beta range in water: 0.07 cm
Critical Organ: bone
ALI: 2 millicuries (ingestion)
Dosimetry: urine bioassay
Shielding: none
Monitoring Methods: thin end window GM or pancake GM wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) If volatile, work only in a hood.
3) If possible internal exposure perform urine bioassay.
4) Monitor with a GM survey meter after each use.
51Cr
Radioactive Half-life: 27.8 days
Mode of Decay: gamma (320 keV, 5 keV)
Critical Organ: lower large intestine
ALI: 40 millicuries (ingestion)
Dosimetry: Internal - urine bioassay or whole body count
External - whole body and ring dosimeter
Shielding: lead
Half-value layer: 2 mm lead
Monitoring Methods: NaI probe, thin end window GM, or pancake GM
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding.
3) Wear whole body and ring dosimeter to monitor external exposure.
4) If volatile, work only in a hood.
5) If possible internal exposure perform urine bioassay and/or whole body count.
6) Monitor with a NaI or GM survey meter after each use.
3H (tritium)
Radioactive Half-life: 12.3 years
Mode of Decay: beta (maximum energy 18.6 keV)
Beta range in air: 6 mm
Beta range in water: 0.006 mm
Critical Organ: whole body for T2O and biological metabolites
ALI: 8 millicuries
Dosimetry: urine bioassay
Shielding: none
Monitoring Methods: wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) If volatile, work only in a hood.
3) If possible internal exposure perform urine bioassay.
4) Wipe test routinely.
125I
Radioactive Half-life: 60.2 days
Mode of Decay: gamma (gamma: 35 keV; x-ray: 27 keV, 31 keV)
Critical Organ: thyroid (as I or I2)
ALI: 40 microcuries (ingestion), 60 microcuries (inhalation)
Dosimetry: Internal - thyroid uptake
External - whole body and ring dosimeter
Shielding: lead
Half value layer: 0.02 mm lead
Monitoring Methods: NaI probe
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding when using millicurie levels.
3) Wear whole body and ring dosimeter to monitor external exposure.
4) If volatile, work only in a hood
5) If possible internal exposure perform thyroid bioassay 6-72 hours after use.
6) Monitor with a NaI survey meter after each use.
131I
Radioactive Half-life: 8.05 days
Mode of Decay: gamma (364 keV, 637 keV, 284 keV, 723 keV, 80 keV)
Critical Organ: thyroid (as I or I2)
ALI: 30 microcuries (ingestion), 50 microcuries (inhalation)
Dosimetry: Internal - thyroid uptake
External - whole body and ring dosimeter
Shielding: lead
Half-value layer: 2.54 mm lead
Monitoring Methods: thin window GM, pancake or NaI probe
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding.
3) Wear whole body and ring dosimeter to monitor external exposure.
4) If volatile, work only in a hood.
5) If possible internal exposure perform thyroid bioassay 6-72 hours after use.
6) Monitor with a NaI or GM survey meter after each use.
22Na
Radioactive Half-life: 2.6 year
Mode of Decay: gamma (511 kev, 1274 keV)
beta (maximum energy 545 keV, 2842 keV)
Beta range in air: 56 inches
Beta range in water: 0.07 inches
Critical Organ: whole body
ALI: 400 microcuries (ingestion), 600 microcuries (inhalation)
Dosimetry: Internal - urine analysis or whole body count
External - whole body and ring dosimeter
Shielding: lead
Half value layer: 0.7 cm lead
Monitoring Methods: thin window GM, pancake GM or NaI probe
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding.
3) Wear whole body and ring dosimeter to monitor external exposure.
4) If volatile, work only in a hood.
5) If possible internal exposure perform urine bioassay and/or whole body count.
6) Monitor with a NaI survey meter after each use.
32P
Radioactive Half-life: 14.3 days
Mode of Decay: beta (maximum energy 1709 keV)
Beta range in air: 610 cm
Beta range in water: 0.76 cm
Critical Organ: bone (as phosphate)
ALI: 600 microcuries (ingestion)
Dosimetry: Internal - urine bioassay
External - film and ring badge
Shielding: plastic
Monitoring Methods: thin end window or pancake GM
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Wear safety glasses or goggles.
3) Use plastic shielding.
4) Wear whole body and ring dosimeter to monitor external exposure.
5) If volatile, work only in a hood.
6) If possible internal exposure perform urine bioassay.
7) Monitor with a GM survey meter after each use.
33P
Radioactive Half-life: 25.4 days
Mode of Decay: beta (maximum energy 249 keV)
Beta range in air: 51 cm
Beta range in water: 0.06 cm
Critical Organ: bone (as phosphate)
ALI: 6 millicuries (oral)
Dosimetry: urine bioassay
Shielding: none
Monitoring Methods: thin end window or pancake GM
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) If volatile, work only in a hood.
3) If possible internal exposure perform urine bioassay.
4) Monitor with a GM survey meter after each use.
35S
Radioactive Half-life: 87.1 days
Mode of Decay: beta (maximum energy 167 keV)
Beta range in air: 26 cm
Beta range in water: 0.04 cm
Critical Organ: whole body or testis (depending on chemical form)
ALI: 10 millicuries (ingestion of sulfides);
6 millicuries (ingestion as elemental S-35)
Dosimetry: urine bioassay
Shielding: none
Monitoring Methods: thin end window or pancake GM
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) If volatile, work only in a hood.
3) If possible internal exposure perform bioassay.
4) Monitor with a GM survey meter after each use.
99mTc
Radioactive Half-life: 6.02 hours
Mode of Decay: gamma (140.51 keV, 18.37 keV, 18.25 keV)
Critical Organ: whole body
ALI: 80 millicuries (ingestion)
Dosimetry: Internal - urine bioassay or whole body count
External - whole body and ring dosimeter
Shielding: lead
Half-value layer: 0.17 mm lead
Monitoring Methods: thin end window GM, pancake GM, NaI probe
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding.
3) Wear whole body and ring dosimetry to monitor external exposure.
4) If volatile, work only in a hood.
5) If possible internal exposure perform bioassay.
6) Monitor with a GM survey meter or NaI probe after each use.
201Tl
Radioactive Half-life: 3.04 days
Mode of Decay: gamma (70.8 keV, 68.9 keV, 80.3 keV, 167.4 keV,
135.3 keV)
Critical Organ: lower larger intestine
ALI: 20 millicuries
Dosimetry: External - whole body and ring dosimeter
Internal - urine bioassay or whole body count
Shielding: lead
Half-value layer: 0.006 mm lead
Monitoring Methods: thin end window GM, pancake GM, NaI probe
wipe test
Safety Precautions:
1) Wear vinyl or latex gloves.
2) Use lead shielding.
3) Wear whole body and ring dosimetry to monitor external exposure.
4) If volatile, work only in a hood.
5) If possible internal exposure perform urine bioassay and/or whole body count.
6) Monitor with a GM survey meter or NaI probe after each use.