Inside Contamination .


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Treatment for Internal Contamination with Radionuclides. Doran Christensen, DO. Associate Director, REAC/TS. Objectives. Understand Principles of Incorporation Know Action Levels for Treatment Know Five Most Common Types of Internal Contamination. 4 Golden Rules of Toxicology.
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Slide 1

Treatment for Internal Contamination with Radionuclides Doran Christensen, DO Associate Director, REAC/TS

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Objectives Understand Principles of Incorporation Know Action Levels for Treatment Know Five Most Common Types of Internal Contamination

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4 Golden Rules of Toxicology (Adapted from Kent Olson, MD FACEP) Treat the Patient before the Poison Prevent or Reduce Exposure Enhance the Elimination of the Agent Consider Specific Adjuncts

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Annual Limit of Intake as far as possible for the measure of radioactive material taken into the body of a grown-up laborer by inward breath or ingestion in a year. ALI is the littler estimation of admission of a given radionuclide in a year by the reference man that would bring about a submitted compelling dosage likeness 5 rems(0.05 sievert) or a conferred measurements likeness 50 rems (0.5 sievert) to any individual organ or tissue. (see 10 CFR 20.1003 .)

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Radiation Accidents can Pose Toxicology Problems The Dose makes the Poison Acute (Threshold Effects) Long-Term Toxicity ALI/MPBB < 1 ALI -No Treatment Necessary 1 - 10 ALI -Consider Short-Term Tx > 10 ALI -Treatment 1 Radiation Protection Dosimetry, Vol 41, No 1, 1992, p. 25

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Sample ALIs Radioisotope ALI-Ingestion ALI-Inhalation (mCi) (mCi) 3 H 80 80 14 C 2 2 32 P 0.6 0.6 33 P 6 8 35 S 10 20 125 I 0.04 0.06 Source – Princeton University, Environmental Health & Safety

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Psychological Aspects of Internal Contamination Radiation Exposure Sometimes Continues Long after Accident Estimates of Dose and Effects are distressingly Variable even among Experts

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Radionuclides versus Different Hazardous Materials Easily Detectable Use Health Physicist Instead of Industrial Hygienist Does not Require Special Clothing for Health Care Providers Not an Immediate Life-Threatening Hazard Can Wait until Patient is Stable before Decontamination

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Use Your Medical or Health Physicist Document Presence of Radionuclides, Activity, Accident Details Collect Samples Documenting Contamination Assist in Decontamination Procedures Calculate/Document Dose Calculations Dispose of Radioactive Waste

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Bioassay is of Limited Value Slow (Days) Must Have Total Collection of Both Urine and Feces Can Overestimate Uptake by Factor of 3 - 5 Specimen May Get Contaminated

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Whole Body Counting Difficult with Actinides Residual Skin Contamination Calibration of Phantoms Deficient Lung Distribution Varies with Time Variable Thickness of Sternum/Chest Wall

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Toxicologic Problem: (Gather Data) Details Radionuclides Involved Laboratory License Maximum Credible Exposure Geometry, Distances, Times Potential for Exposure Poison Control Analogy

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Hospital Resources Radiologist or Nuclear Medicine Physician Medical or Health Physicist Radiation Safety Officer ( RSO ) Nuclear Medicine Decontamination Area Nuclear Medicine Gamma Camera

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Hospital NM Gamma Camera For Selected Internal Contamination Radionuclide WBC (MDA in air) Gamma Camera (MDA in air) G-M Survey Counter Scatter Media (MDA in air) 125 I 030-2.62 3.68-29.90 90 201 Tl 0.20 0.51-0.69 2.40-3.48 188 99m Tc 0.09 0.37-0.39 1.15-1.53 144 111 In 0.12 0.40-0.56 1.36-1.64 165 133 Ba 0.11 0.71-0.89 1.88-2.50 20 131 I 0.12 0.56-1.09 1.51-2.71 59 85 Sr 0.11 0.68-0.99 1.85-3.22 90 137 Cs 0.13 1.04-2.26 2.47-4.03 59 54 Mn 0.10 1.06-1.84 2.70-4.24 38 60 Co 0.10 1.27i-1.48 2.11-3.15 14

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External Resources State Radiological Health Department Radiation Emergency Assistance Center/Training Site (REAC/TS) - 865/576-1005 CHEMTREC (for HazMat segments just) 800/424-9300

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Other External Resources Agency for Toxic Substances Disease Registry (ATSDR) 24 Hour Line 404/639-0615 (No Answer) Dept Of Energy (DOE) Emergency Operations Center 24 Hour Line 202/586-8100 Nuclear Regulatory Commission (NRC) 24 Hour Line 301/816-5100 301/951-0550

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Internal Contamination Ramifications Isolation During Therapy? Follow-up for Possibly Long Periods Counseling for Carcinogenic Implications of Exposure

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Internal Contamination - Involves 4 Stages Deposition Along Route of Entry Translocation Incorporation (Deposition in the Target Organ) Clearance

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Preventing Incorporation Interception Before Radionuclide Reaches Target Organs Decrease Body Uptake Vomit/Lavage Charcoal/Catharsis Other Methods

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Considerations in Treatment for Internal Contamination Chemical Toxicity of Substance Solubility (D,W,Y) Particle Size Quantity Half-existence of Radionuclide: Physical Biological Effective

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Respiratory Tract Clearance Time 1 Segment Time (hours) Anterior nare 1.0 Nasopharynx 0.1 (10 mm/min) Trachea 0.1 Bronchi 1.0 Bronchioles 4.0 Terminal Bronchioles 10.0 Alveoli 100+ days 1 ICRP #30 Model (1979)

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Particle Size and Deposition Fraction

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Nasopharynx Clearance Time 1 Anatomy Clearance Time (min) Anterior nare 60 Nasopharynx 10 (10 mm/min) 1 ICRP #30 Model (1979)

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Gastrointestinal Tract Residence Times 1 Portion Residence Time (hours) Stomach 6/24 Small Intestine 14/24 Upper Colon 18/24 Lower Colon 24/24 1 ICRP #30 Model (1979) (Assumes Stable Substances)

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Schematic Model of Radionuclide Uptake (After Voelz) Ingestion Inhalation Surface Intake: Lung Clearance Skin 1. In place 2. Wounds Lung GI Tract Lymph Nodes Uptake: Blood (Recycle) Kidney Deposition Sites 1. Entire Body 2. Bone 3. Liver 4. Thyroid Excretion: Feces Urine

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Treatment of Internal Emitters TIME: Within 3 hrs, if Possible BENEFIT: 2 to 10 Reduction of Organ Dose RISKS: Minimal, aside from Lung Lavage/ Some Drugs DECISION: Go to Potential Exposure History, Not Dose

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Physiologic Principles Used in Radionuclide Decorporation GI Tract Removal/Enhanced Elimination Dilution of Isotope Displacement Blocking Alkalinization Chelation

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Reduction of Absorption from Gastrointestinal Tract Antacid Precipitation into Soluble Salt Catharsis

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Iodine/Technetium - Block 131 I - Eff Half Life = 7.6 days 99m Tc - Eff Half Life = 1 day* Treat inside 4 Hours ( Best 1 Hour Before Exposure! ) KI or NaI 300 mg tablet SSKI (1 g/ml) - 5 - 6 drops in water Povidone Iodine Theoretically Useful NCRP Report No 65, p 83-86, 104

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Tritium - Dilute Beta Emitter 2% Binds to Cellular Components Essentially Occupies TBW Space Force Fluids 3 - 4 L/day Reduces Half-Time by 1/3 - 1/2 NCRP Report No 65, p 105-106

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Beer Therapy for Tritium

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Chelation Agents DTPA - Transuranics (not Uranium) EDTA - Lead (and others) BAL - Lead, Polonium, Gold, Indium DFOA - Iron, Manganese PCA - Copper, Lead, Mercury , Zinc, Cobalt, Gold DMPS - Mercury (not in US) DMSA - Lead (and Others)

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Comparison of EDTA and DTPA HOOC-H 2 C CH 2 - COOH N-CH 2 - CH 2 - N CH 2 - COOH HOOC-H 2 C EDTA - Ethylenediaminetetraacetic Acid CH 2 - COOH HOOC-H 2 C N-CH 2 - CH 2 - N-CH 2 - CH 2 - N CH 2 HOOC-H 2 C CH 2 - COOH DTPA - Diethylenetriaminepentaacetic Acid

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DTPA Administered for Soluble 239 Pu Within One Hour Retention Organ Control DTPA Treated Liver 14% 0.47% Skeleton 57.0% 5.9%

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Insoluble Prussian Blue Effective for Cs-137 Binds Ions in the Gut Biological Half-Life Reduced to 1/3 Not Systemically Absorbed Side Effects - Constipation, GI Upset at Higher Doses (20 g/day)

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Lung Lavage Does Not Need to be Done Emergently 1 ( 3-5 days after Exposure ) Lavage Technique for Pulmonary Alveolar Proteinosis For bigger testimonies 50 2 - 100 1 ALIs Common Bronchoscopic Lavage (has not been assessed for adequacy) 1 Radiation Protection Dosimetry, Vol 41, No 1, 1992, pp. 32-33. 2 Safety Series No. 47, Vienna: IAEA, 1978, p 23.

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Uranium Compounds and Solubility Classes 1 Solubility Compound Class UF 6 (Uranium Hexafluoride) D UO 2 (NO 3 ) 2 (Uranyl Nitrate) D UO 3 (Uranium Trioxide) D UO 2 Cl 2 (Uranyl Chloride) D UO 4 (Uranium Peroxide) W UO 2 (Uranium Dioxide) W,Y UC 2 (Uranium Dicarbide) Y UO 2 (High-Fired Uranium Dioxide) Y 1 Adapted From Biokinetics and Analysis of Uranium in Man , Hanford Environmental Health Foundation for the US Dept of Energy, 1984

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Uranium in Biological Fluids pH 6.5 - 8 Principal/Most Easily Transported Form of Serum U is Biscarbonato Complex, UO 2 (CO 3 ) 2+ Uranyl Citrate Complex likewise shaped Weak Complex of UO 2 2+ and Iron-Transport Protein, Transferrin additionally Forms in Plasma Adapted From Biokinetics and Analysis of Uranium in Man , Hanford Environmental Health Foundation for the US Dept of Energy, 1984

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Uranium Deposition in Kidney Some of Bound UO 2 2+ is Retained in Kidney Renal Retention Enhanced by: Large Amounts of U Acidic Urine U Kidney Release Half-time is 15 d Enhanced by Alkaline Urine Adapted From Biokinetics and Analysis of Uranium in Man , Hanford Environmental Health Foundation for the US Dept of Energy, 1984

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Uranium - Alkalinize Urine 235 U - Gamma Eff Half Time Depends on Solubility At Normal Enrichment Levels, Primary Renal Toxicity Maintain Urine pH 7.5 to 8 Use Bicarbonate tablets (Do not utilize Alka Seltzer from old writings!) Use Supplemental KCl tablets

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