Radioactive Materials at CSUF 
Here is information about some of the radioactive materials used on campus:
CARBON 14
PHYSICAL DATA
- Beta Energy: 156 keV (maximum) 49 keV (average) (100% abundance)
- Physical Half-Life: 5730 years
- Biological Half-Life: 12 days
- Effective Half-Life: 12 days (Bound)
- Effective Half-Life: 40 days (Unbound)
- Specific Activity: 4460 mCi/gram
- Maximum Beta Range in Air: 24.00 cm = 10 inches
- Maximum Beta Range in Water/Tissue: 0.28 mm = 0.012 inches
- Maximum Range in Plexiglas/Lucite/Plastic: 0.25 mm = 0.010 inches
- Fraction of 14C beta particles transmitted through dead layer of skin: At 0.007 cm depth = 1%
RADIOLOGICAL DATA
- Critical Organ: Fat Tissue
- Routes of Intake: Ingestion, Inhalation, Skin Contact
- External exposure: Deep dose from weak 14C beta particles is not a radiological concern.
- Internal exposure & contamination: primary radiological concerns
- Committed Dose Equivalent (CDE): 2.08 mrem/uCi (ingested) (Fat Tissue) 2.07 mrem/uCi (puncture) 2.09 mrem/uCi (inhalation)
- Committed Effective Dose Equivalent (CEDE): 1.54 mrem/uCi (ingested)
- Annual Limit on Intake (ALI): 2 mCi (ingestion of labeled organic compound) 2000 mCi (inhalation of carbon monoxide) 200 mCi (inhalation of carbon dioxide) *[1.0 ALI = 2 mCi (ingested C-14 organic compound) = 5,000 mrem CEDE]
- Skin Contamination Dose Rate: 1090-1180 mrem per 1.0 uCi/cm2 (7 mg/cm2 depth) * Dose Rate to Basal Cells from Skin Contamination 1.0 uCi/cm2 = 1400 mrad/hour. * Immersion in 14C Contaminated Air = 2.183E7 mrem/year per uCi/cm3 at 70 um depth of tissue and 4.07E6 mrem/year per uCi/cm3 value averaged over dermis.
SHIELDING
- None required (? 3 mm plexiglass)
SURVEY INSTRUMENTATION
- Can detect 14C using a thin-window G-M survey meter; survey meter probe must be at close range (1 cm.) G-M survey meters have very low counting efficiency for 14C (5%)
- Liquid scintillation counter (indirect counting) may be used to detect removable 14C on wipes
RADIATION MONITORING DOSIMETERS
- Not Needed (beta energy too low)
- 14C Beta Dose Rate: 6.32 rad/hr at 1.0 in air per 1.0 mCi 14C
- Skin Contamination Dose Rate: 13.33 mrad/hr per uCi on skin
- Dose Rate from a 1 mCi isotropic point source of 14C: Distance Rad/Hr 1.0 cm 1241.4 2.0 cm 250.4 15.2 cm 0.126 20.0 cm 0.0046
GENERAL RADIOLOGICAL SAFETY INFORMATION
- Urinalysis: Not required; however, prudent after a 14C radioactive spill or suspected intake.
- Inherent volatility (at STP): Not Significant.
- Possibility of organic 14C compounds being absorbed through gloves.
- Care should be taken NOT to generate 14CO2 gas, which could be inhaled.
- Internal Dose is the concern: Skin contamination, ingestion, inhalation, and puncture.
- Always wear a lab coat and disposable gloves when working with 14C.
- The concentration of carbon in adipose tissue, including the yellow marrow, is about 3 times the average whole body concentration. No other organ or tissue of the body concentrates stable carbon to any significant extent.
- The fractional absorption of dietary carbon (uptake to blood) is usually in excess of 0.90.
- Three main classes of carbon compounds may be inhaled: organic compounds, gases (CO or CO2), and aerosols of carbon containing compounds such as carbonates and carbides.
- Organic Compounds - most organic compounds are NOT very volatile under normal circumstances; the probability of these being inhaled as vapors is therefore small. In circumstances where such substances are inhaled, it would be prudent to assume that once they enter the respiratory system they are instantaneously and completely translocated to the systemic circulation without changing their chemical form.
- Gases - the inhalation of CO and its retention in body tissues has been studied extensively. Since gas has a relatively low solubility in tissue water, doses due to absorbed gas in tissues are insignificant in comparison with doses due to the retention of CO bound to hemoglobin. CO2 in the blood exists mainly as a bicarbonate.
- Carbonates & Carbides - It is assumed that inhaled or ingested 14C labeled compounds are instantaneously and uniformly distributed throughout all organs & tissues of the body where they are retained with a biological half-life of 12-40 days
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Copper-67 [67Cu]
PHYSICAL DATA
- Gamma Energy 184.6 keV
- Beta Energy 580 keV
- Physical Half-life 2.58 Days
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HYDROGEN-3 [3H]
PHYSICAL DATA
- Beta Energy: 18.6 keV (maximum) 5.7 keV (average) (100% abundance)
- Physical Half-Life: 12.3 years
- Biological Half-Life: 10-12 days
- Effective Half-Life: 10-12 days
Forcing liquids to tolerance (3-4 liters/day) will reduce the effective half-life of 3H by a factor of 2 or 3. (Relatively easy to flush out of system with fluids.)
- Specific Activity: 9640 Ci/gram
- Maximum Beta Range in Air: 6 mm = 0.6 cm = 1/4"
- Maximum Beta Range in Water: 0.006 mm = 0.0006 cm = 3/10,000"
- Penetrability in Matter or Tissue: Insignificant
[0% of beta particle energy transmitted through dead layer of skin]
RADIOLOGICAL DATA
- Least radiotoxic of all radionuclides.
- Critical Organ: Body Water or Tissue
- Routes of Intake: Ingestion, Inhalation, Puncture, Wound, Skin Contamination (Absorption)
- External exposure from weak 3H beta energy - not a radiological concern
- Internal exposure & contamination are primary radiological concerns.
- Committed Dose Equivalent (CDE): 64 mrem/mCi (ingested) 64 mrem/mCi (inhaled) 64 mrem/mCi (puncture)
- Committed Effective Dose Equivalent (CEDE): 90 mrem/mCi (ingested) 63 mrem/mCi (inhaled)
- Annual Limit on Intake (ALI): 80 mCi (ingestion or inhalation) [3H2O] [1.0 ALI = 80 mCi (3H) = 5,000 mrem CEDE]
- Skin Contamination Exposure Rate: 57,900 mrad/hr/mCi (contact)
Exposure rate to dead layer of skin only.
Skin contamination of 1.0 uCi/cm2 = 0 mrad/hr dose rate to basal cells.
- Rule of Thumb: 0.001 uCi/ml of 3H in urine sample is indicative of a total integrated whole body dose of approximately 10 mrem (average person) if no treatment is instituted (i.e., flush with fluids); [NCRP-65, 1980]
SHIELDING
SURVEY INSTRUMENTATION
- CANNOT detect 3H using a G-M or NaI survey meter.
- Liquid scintillation counter (indirect) is the only monitoring method
RADIATION MONITORING DOSIMETERS
- (Whole Body Badge or Finger Rings): Not Needed (beta energy too low)
RADIOACTIVE WASTE
- Solid, liquids, scintillation vials, pathological materials, animal carcasses
REGULATORY COMPLIANCE INFORMATION
- Derived Air Concentration (DAC): 2.0E-5 uCi/cc (occupational)
- Airborne Effluent Release Limit: 1.0E-7 uCi/cc [Applicable to the assessment & control of dose to the public (10 CFR 20.1302). If this concentration was inhaled continuously for over one year the resulting TEDE would be 50 mrem.]
- Controlled Area Removable Contamination Limit: 2,200 dpm/100 cm2
- Urinalysis (Byproduct License): required when handling greater than or equal to 100 mCi 3H
GENERAL RADIOLOGICAL SAFETY INFORMATION
- Inherent Volatility (at STP): Substantial
- Experimental uses include: total body water measurements & in-vivo labeling of proliferatory cells by injection of tritium-labeled compounds (i.e., thymidine). Tritium labeling is also used in a variety of metabolic studies.
- Oxidation of 3H gas in air is usually slow.
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IODINE-125 [125I]
PHYSICAL DATA
- Gamma Energies: 35.5 keV (7% abundance/93% internally converted gamma) (No betas emitted) 27.0 keV (113%, x-ray) 27-32 keV (14%, x-ray) 31.0 keV (26%, x-ray)
- Specific Gamma Ray Constant: 0.27 to 0.70 mR/hr per mCi at 1 meter (Current literature indicates 0.27 mR/hr per mCi at 1 meter)
- Physical Half-Life: 60.1 days
- Biological Half-Life: 120-138 days (unbound iodine)-thyroid elimination
- Effective Half-Life: 42 days (unbound iodine)-thyroid gland.
- Specific Activity: 17,400 Ci/gm (theoretical/carrier free)
- Intrinsic Specific Activity: 22.0 Ci/millimole
RADIOLOGICAL DATA
- Critical Organ (Biological Destination): Thyroid
- Routes of Intake: Ingestion, inhalation (most probable), puncture, wound, skin contamination (absorption)
- External and internal exposure and contamination concerns exist in use of 125I
- Committed Dose Equivalent (CDE): 814 mrem/mCi (thyroid/inhalation/class "D") (Organ Doses) 1185 mrem/mCi (thyroid/ingestion/NaI form) 910 mrem/mCi (thyroid/inhalation) 1258 mrem/mCi (any organ/puncture/adult)
- Committed Effective Dose Equivalent (CEDE): 24 mrem/mCi (whole body/inhalation)
SHIELDING
- Lead foil or sheets (1/32 to 1/16 inch thick): 0.152 mm lead foil
- Half Value Layer: 0.02 mm - 0.008 inches
SURVEY INSTRUMENTATION
- Survey meter equipped with a low energy NaI scintillation probe is necessary.
- Survey meters equipped with GM pancakes or end window GM probes are inefficient. These probes are not useful for contamination monitoring, as they are only about 0.1% efficient.
DOSE RATES (from unshielded 1.0 mCi isotropic point source)
- Distance mrads/hr 1.00 cm 156 - 275 10.00 cm 15.5 - 27.5 100.00 cm 0.156 - 0.28 6.00 in 6.5 (Some literature indicates 0.7 mrad/hr per mCi at 100 cm.)
- Individuals who will be using 125I in the NaI or KI chemical form are required to obtain a thyroid scan to be used as a baseline reference prior to use.
- The thyroid gland accumulates 20 - 30% of the soluble radioiodine taken in by the body. All radioiodines in the body can be assumed to be eliminated quite rapidly via the urine.
- Thyroid Bioassay is required by law when handling greater than or equal to 1 mCi in the NaI or KI chemical form. In accordance with the NRC license and MSU's commitment to ALARA, the threshold amount is taken to be 0.1 mCi. The thyroid scan is to be obtained not less than 24 hours but not more than one week after the handling or use of that quantity and form of 125I. In addition, all workers who assist or observe in manipulations of the above quantity and type of 125I, or are sufficiently close to the process so that intake is possible (within a few meters and in the same room) are required to obtain thyroid scans under the same conditions listed above.
- Fume hood sash glass provides adequate shielding for most iodinations. Extra shielding is not recommended, since it impedes airflow into the hood.
- Shielding is not required for most uses of this nuclide due to the low energy and low amounts typically used.
- Use a cannula adaptor needle to vent stock vials of 125I used for iodinations. This prevents puff releases.
- Segregate waste from iodinations (free) from other (bound) 125I waste and store it in the fume hood, in tightly sealed Ziploc bags (solid waste) or screw top containers (liquid waste) until waste pickup.
- Cover test tubes used to count or separate fractions from iodinations with parafilm or other tight caps to prevent release while counting or moving outside the fume hood.
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IRON-59 [59Fe]
PHYSICAL DATA
- Gamma Energy: 1,292 keV (44%) 1,110 keV (56%) 192 keV (2.8%) 143 keV (0.8%)
- Beta Energy: 1,570 keV (0.3%) 475 keV (54%) 270 keV (46%)
- Physical Half-Life: 45 days
- Biological Half-Life: 800 days (Total body)
- Effective Half-Life: 42.7 days (Total body)
- Specific Gamma Ray Constant: 6.4 mRem/hr per mCi at 1 meter
RADIOLOGICAL DATA
- Critical Organs: Gastrointestinal tract, Spleen
- Results of Intake: Ingestion, Puncture, Wound
- Internal and Exposure Contamination: Concerns exist in the use of Fe-59
- Committed Dose Equivalent (CDE): researching
- Committed Effective Dose Equivalent (CEDE): researching
SURVEY INSTRUMENTATION
- Survey meter equipped with NaI scintillation probe is best, but a GM-type survey meter can be used
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PHOSPHORUS 32
PHYSICAL DATA
- Beta energy: 1.709 MeV (maximum) 0.690 MeV (average, 100% abundance)
- Physical half-life: 14.3 days
- Biological half-life: 1155 days
- Effective half-life: 14.1 days (bone) /13.5 days (whole body)
- Specific activity: 285,000 Ci/gm
- Maximum range in air: 610cm = 240 inches = 20 feet
- Maximum range in water/tissue: 0.76 cm = 1/3 inch
- Maximum range in plexiglas /lucite/plastic: 0.61 cm = 3/8 inch
- Half-Value Layer (HVL): 2.00 mm (water/tissue)
RADIOLOGICAL DATA
- Critical organ (biological destination) (soluble forms): Bone
- Critical organs (insoluble forms or non-transportable 32P compounds): Lung (inhalation) and G.I. tract/lower large intestine (ingestion)
- Routes of intake: Ingestion, inhalation, puncture, wound, skin contamination (absorption)
- External and internal exposure from 32P
- Committed Dose Equivalent (CDE): 32 mrem/mCi (ingested) (Organ Doses) 37 mrem/mCi (puncture) 22 mrem/mCi (inhaled/Class D/bone marrow)
- Coed Effective Dose Equivalent (CEDE): 7.50 mrem/mCi (ingested/WB) 5.55 mrem/mCi (inhale/Class D) 13.22 mrem/mCi (inhale/Class W)
- Skin contamination dose rate: 8700-9170 mrem/mCi/cm2 (7 mg/cm2 or 0.007 cm depth in tissue)
- Dose rate to basal cells from skin contamination of 1.0 mCi/cm2 (localized dose) = 9200 mrad/hr
- Bone receives approximately 20% of the dose ingested or inhaled for soluble 32P compounds.
- Tissues with rapid cellular turnover rates show higher retention due to concentration of phosphorous in the nucleoproteins.
- 32P is eliminated from the body primarily via urine.
SURVEY INSTRUMENTATION
- GM survey meter and a pancake probe.
- Low-energy NaI probe is used only to detect Bremsstrahlung x-rays.
- Liquid scintillation counter (indirect counting) may be used to detect removable surface contamination of 32P on smears or wipes.
DOSE RATES (from unshielded 1.0 mCi isotropic point source)
- Distance Rads/hr 1.00 cm 348 15.24 cm 1.49 10.00 ft 0.0015
- 780,000 mrad/hr at surface of 1.0 mCi 32P in 1 ml liquid.
- 26,000 mrad/hr at mouth of open vial containing 1.0 ml 32P in 1.0 ml liquid.
SHIELDING
- 3/8 inch thick plexiglas/acrylic/lucite/plastic/wood.
- Do not use lead foil or sheets! Penetrating Bremsstrahlung x-ray will be produced!
- Use lead sheets or foil to shield Bremsstrahlung x-rays only after low density plexiglas/acrylic/lucite/wood shielding
GENERAL PRECAUTIONS
- Because it is a bone seeker, special precautions must be taken to minimize any chance of introducing into the body.
- Airborne contamination can be generated through drying (dust), rapid boiling, or expelling solutions through syringe needles and pipette tips, due to aerosols.
- Personnel radiation monitors (whole body and finger rings) are required when handling greater than 1.0 mCi of 32P at any time.
- Never work directly over an open container; avoid direct eye exposure from penetrating 32P beta particles.
- Always wear a lab coat and disposable gloves when handling 32P.
- Monitor personnel work areas and floors using a GM survey meter equipped with a pancake (beta) probe, for surface contamination.
- Monitor for removable surface contamination by smearing, or wiping where 32P is used.
- Use low-density (low atomic number) shielding material to shield 32P and reduce the generation of Bremsstrahlung x-rays. The following materials are low atomic number materials: Plexiglas, acrylic, lucite, plastic, wood, or water.
- Do NOT use lead foil, lead sheets, or other high density materials (metals) to shield 32P directly. Materials with atomic number higher than that of aluminum (Z =13) should NOT be used. Penetrating Bremsstrahlung x-rays will be generated in lead and other high density shielding material.
- Safety glasses or goggles are recommended when working with 32P.
- Typical GM survey meter with pancake probe efficiency is greater than or equal to 45%. Typical liquid scintillation counter counting efficiency for 32P (full window/maximum) greater than or equal to 85%.
- Typical detection limit of 32P in urine specimens using a liquid scintillation counter = 1.1 x 10-7uCi/ml
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PHYSICAL DATA
- Beta energy: 167 keV (maximum) 53 keV (average) (100% abundance)
- Physical Half Life: 87.4 days
- Biological Half Life: 623 days (unbound 35S)
- Effective Half Life: 44-76 days (unbound 35S)
- Specific Activity: 42,400 Ci/g
- Maximum Beta Range in Air: 26.00 cm. = 10.2 in.
- Maximum Beta Range in Water or Tissue: 0.32 mm. = 0.015 in.
- Maximum Beta Range in Plexiglas or Lucite: 0.25 mm. = 0. 01 in.
- Fraction of 35S betas transmitted through dead layer of skin = 12%
RADIOLOGICAL DATA
- Critical organ: Testis
- Routes of Intake: Ingestion, inhalation, puncture, wound, skin contamination (absorption)
- External exposure (deep dose) from weak 35S beta particles is not a radiological concern.
- Internal exposure and contamination are the primary radiological concerns.
- Committed dose equivalent (CDE): 10.00 mrem/uCi (ingested) 0.352 millirem/uCi (puncture)
- Committed Effective Dose Equivalent (CEDE): 2.6 mrem l/uCi (ingested) (Assumes a 90 day biological half life)
- Annual Limit on Intake (ALI)*: 10 mCi (ingestion of inorganic 35S compounds) 6 mCi (Ingestion of elemental 35S) 8 mCi (ingestion of sulfides or sulfates/LLI)** 10 mCi (inhalation of 35S vapors) 20 mCi (inhalation of sulfides or sulfates) 2 mCi (inhalation of elemental 35S) *1.0 ALI = 10 mCi (inhaled 35S vapors) = 5,000 mrem CEDE **1.0 ALI = 8 mCi (ingestion sulfides/sulfates LLI) = 50,000 mrem CDE * Skin Contamination Dose Rate: 1,170 - 1,260 mrem/1.0 uCi/cm2 (7.0 mg/cm2 depth) * Beta Dose Rates for 35S: 14.94 rad/h (contact) in air per 1.0 mCi 0.20 rad/h (6 inches) in air per 1.0 mCi
SHIELDING
- None required (? 3 mm Plexiglas shields; shielding optional)
SURVEY INSTRUMENTATION
- Can detect using a thin window G-M survey meter (pancake), however, probe MUST be at close range, recommend 1 cm distance.
- G-M survey meter has low efficiency, usually 4 - 6%.
- Liquid scintillation counter (wipes, smears) may be used for secondary, but will NOT detect non-removable contamination!
RADIATION MONITORING DEVICES
- Badges: Not needed, because 35S beta energy is too low, and is not an external radiation hazard.
- Dose Rate from a 1 millicurie unshielded isotropic point source of 35S: Distance Rad/Hr 1.0 cm 1173.6 2.5 cm 93.7 15.24 cm 0.2 20.00 cm 0.01
GENERAL RADIATION SAFETY INFORMATION
- Urinalysis: Not required, but may be requested by Health Physics staff after a spill or personnel contamination involving 35S.
- Inherent volatility (STP): SIGNIFICANT for 35S methionine and cysteine.
- Radiolysis of 35S amino acids (cysteine and methionine) during storage and use may lead to the release of volatile impurities. Volatile impurities are small (? 0.05%)
- Metabolic behavior of organic compounds of sulfur (cysteine and methionine) differs considerably from the metabolic behavior of inorganic compounds.
- Organic compounds of sulfur (cysteine and methionine) become incorporated into various metabolites. Thus, sulfur entering the body as an organic compound is often tenaciously retained.
- The fractional absorption of sulfur from the gastrointestinal tract is typically >60% for organic compounds of sulfur. Elemental sulfur is less well absorbed from the GI tract than are inorganic compounds of the element (80% for all inorganic compounds and 10% for sulfur in its elemental form).
- Elemental sulfur is an NRC inhalation Class W (meaning it is retained for weeks in the body).
- Inhalation of the gases SO2, COS, H2S, and CS2 must be considered. Sulfur entering the lungs in these forms is completely and instantaneously translocated to the transfer compartment; from there, its metabolism is the same as that of sulfur entering the transfer compartment following ingestion or inhalation of any other organic compound of sulfur.
- Contamination of internal surfaces of storage and reaction vessels may occur (rubber stoppers, gaskets or o rings).
- Vials of 35S labeled cysteine and methionine should be opened and used in ventilated enclosures (exhaust hoods).
- The volatile components of 35S labeled amino acids should be opened and used in ventilated enclosures (exhaust hoods).
- The volatile components of 35S labeled cysteine and methionine are presumed to be hydrogen sulfide (H2S) and methyl mercaptan (CH3SH), respectively.
- 35S vapors may be released when opening vials containing labeled amino acids, during any incubating of culture or cells containing 35S, and the storage of 35S contaminated wastes.
- Excessive contamination can be found on the inside surfaces and in water reservoirs of incubators used for 35S work. Most notable surface contamination can be found on rubber seals of incubators and centrifuges.
- Radiolytic breakdown may occur during freezing processes, releasing as much as 1.0 uCi of 35S per 8.0 mCi vial of 35S amino acid during the thawing process.
- 35S labeled amino acids work should be conducted in an exhaust hood designated for radiolytic work.
- Vent 35S amino acid stock vials with an open-ended charcoal-filled disposable syringe. Activated charcoal has a high affinity for 35S vapors.
- Place an activated carbon or charcoal canister, absorbent sheet, or tray (50-100 grams of granules evenly distributed in a tray or dish) into an incubator to passively absorb 35S vapors. Discard absorbers that exhibit survey meter readings above normal area background levels in the solid radioactive waste.
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