Unexpected Radiation Exposure Scenarios Timur Durrani, MD, MPH, MBA Associate Professor of Medicine, UCSF Site Occupational Medical Director, LBNL March 7, 2020 Outline • The Advanced Light Source (ALS) • Expected radiation exposure scenarios • Review of types of radiation • Overview of radiation assessment • Examples of radiation injury and treatment • Unexpected radiation exposure scenarios
The Advanced Light Source (ALS) A specialized particle accelerator that generates bright beams of x-ray light for scientific research. Electron bunches travel at nearly the speed of light in a circular path, emitting ultraviolet and x-ray light in the process. The light is directed through about 40 beamlines to numerous experimental end stations, where scientists can conduct research in a wide variety of fields, including materials science, biology, chemistry, physics, and the environmental sciences. The wavelengths of the synchrotron light span the electromagnetic spectrum from infrared to x-rays and have just the right size and energy range for examining the atomic and electronic structure of matter. ALS Beamlines The Electromagnetic Spectrum https://www.ehs.washington.edu/radiation/non-ionizing-radiation-safety
http://nuclearsafety.gc.ca/eng/resources/radiation/introduction-to-radiation/types-and-sources-of-radiation.cfm Annual outdoor effective dose from cosmic radiation for North America, 2004 http://nuclearsafety.gc.ca/eng/resources/radiation/introduction-to-radiation/types-and-sources-of-radiation.cfm Metals in Earth’s crust Abundance (atom fraction) of the chemical elements in Earth’s upper continental crust as a function of atomic number. U.S. Geological Survey Fact Sheet 087-02
Ionizing Radiation Exposure to the Public USNRC Technical Training Center: https://www.nrc.gov/reading-rm/basic-ref/students/for-educators/06.pdf The atom Radioactive Decay
How x-rays work Types of Ionizing Radiation Alpha – concern for internal contamination (i.e. Radon) Beta – concern for internal and external contamination Gamma – like X-rays, but emitted from nucleus, X-ray emitted from electrons. Concern for internal contamination. Neutrons – uncharged particles from the nucleus. More potent than Gamma Rays. Have the ability to make something else radioactive. Ionizing Radiation Paper Concrete Plastic Lead α β γ neutron
Periodic Table Categories of Isotopes University Five 14 C, 32 P, 125 I, 131 I, 252 Cf Industrial three: 192 IR, 137 Cs, 60 Co Military five: 3 H, 235 U, 238 U, 239 Pu, 241 Am Fission/Activation products: • Iodine • Strontium • Cesium • Uranium • Plutonium How Fission works Large atom (Plutonium) bombarded with neutrons, causes the atom to split (fission) in uneven products Plutonium (235) = Strontium (87) + Cesium (132) + Neutrons The core of a fission bomb is either plutonium or highly enriched uranium. These are the only materials that can achieve a self- sustaining chain reaction.
Example Chain reaction Fission Yield of U-233, U-235, P-239 Fission Yield % Atomic Mass
Types of Fission Materials Uranium – 235 (comes out of the ground) • 5% used in reactors • 20% used in weapons Plutonium (comes out of a lab) Units Curie (Ci) basic unit of radioactivity in US Dose refers to the absorption of radiation energy per unit mass of absorber. The conventional (USA) dose unit is the rad. The SI dose is the Gray. • 1 Gy = 100 rad Annual Regulatory Limits (US NRC) Non-Occupational rem ~Gray Members of the Public 0.1 0.001 Occupational Whole Body (internal + external) 5 0.05 Any individual organ 50 0.5 Lens of the Eye 15 0.15 Skin 50 0.5 Extremities 50 0.5 Fetal Dose (declared pregnancy) 0.5 0.005
How this works practically Source is determined to be α , β , or γ using the Geiger Counter Geiger Counter takes initial measurement (in counts per minute). This gets converted to Rad/Rem and compared to the Annual Regulatory Limits to determine if it is a medical/regulatory problem Medical Testing Andrews Lymphocyte Example Nomogram Nasal Swab CBC w/diff Dicentromere cytogenetics Bioassays (urine/feces). Andrews, G.A., Lushbaugh, C.C., & Auxier, J.A. (1965). The Importance of Dosimetry to the Medical Management of Persons Accidentally Exposed to High Levels of Radiation. International Atomic Energy Agency (IAEA): IAEA. Strange and Schafermeyer's Pediatric Emergency Medicine, Fourth Edition (Strange, Pediatric Emergency Medicine) 4th Ed. CHAPTER 142 Radiation Emergencies Radiation exposure is toxic exposure Radiation is toxicity by energy Mechanism of action: breaks chemical bonds in DNA, produces ions and free radicals Dose estimation: depends on type of agent, activity of agent, and exposure Exposure is dependent on duration of exposure ( time ) proximity of exposure ( distance ) and protection ( shielding )
Radiation injury appears depending on dose Higher doses cause injury sooner (days) than lower doses (weeks). – Immediate: Redness, swelling, blisters, ulceration, tissue necrosis – Delayed: Fibrosis, atrophy (sclerosis), and telangiectasia formation, cancer Acute Radiation Syndromes Dose (Gray) Syndrome Effects 1-2 Hematopoietic ~100% Survival without treatment 3-5 Gastrointestinal LD 50/60 without treatment 6-8 LD 50/60 with supportive care 9-10 Consider Stem Cell transplant 10+ Neurovascular Multiple Organ failure, probable death LD 50/60 - 50% death of exposed in 60 days Cutaneous Radiation Injury Dose (Gray) Injury Onset 3 Epilation (hairloss) 14 – 21 days 6 Erythema Waxes/Wains, early as few hours to 14 – 21 days 10 – 15 Dry desquamation 20 days 15 – 25 Wet desquamation 14 – 21 days
Exposure scenarios Electron Accelerator Accident INTERNATIONAL ATOMIC ENERGY AGENCY, An Electron Accelerator Accident in Hanoi, Viet Nam, , IAEA, Vienna (1996). Diagram of accelerator facilities and offices Footer 33
Diagram of the microtron accelerator Diagram of exposure position Local Injury Day 14 Day 28 Footer 35 Ongoing Day 113 Estimated dose to right hand Footer 36
Uncontrolled medical therapy source, Cs 137 INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Goiania, IAEA, Vienna (1988). Footer 37 Abandoned Radiotherapy Clinic Radiation Therapy Schematic Footer 39
Cesium Chloride Luminescent CsCl Source Capsule http://fukushima-is-still-news.over-blog.com/article-new-test- makes-cesium-glow-113739873.html The Human Toll • 249 people were contaminated. • 20 people were admitted to the hospital. • 4 of the casualties died within four weeks of their admission to hospital. • The post-mortem examinations showed hemorrhagic and septic complications associated with the acute radiation syndrome. • The best independent estimates of the total body radiation doses of these four people, by cytogenetic analysis, ranged from 4.5 Gy to over 6 Gy. Uncontrolled Industrial radiography source, Ir 192 INTERNATIONAL ATOMIC ENERGY AGENCY, The Radiological Accident in Yanango, , IAEA, Vienna (2000).
Industrial Radiography Industrial radiography is used throughout the world to examine the structural integrity of materials in a non- destructive manner. https://www.ansndt.com/standard-ndt-services/radiography/ http://sitasndt.com/radiographic-testing/#1474863856061-3beab139-e78e https://www.magnumndt.com/an-introduction-to-industrial- radiography-2019-blog Ir 192 ‘Pigtail’ Housing Container ‘Camera’ The incident Day 2 • The source became detached from the ‘camera’. • At 4pm, a welder picked up the unshielded source with his right hand and placed it in the back right pocket of his trousers • At 9pm he felt a pain in the back of his right thigh. • At 10:30pm he complained to his wife about the pain and she looked at his posterior right thigh and noted a red area of skin.
The incident continued He took off his jeans and, with the source still in the pocket, placed them on the floor. He visited a local doctor who told him he had an "insect bite" and that he should put a hot compress on the area. The welder's wife meanwhile spent about five to ten minutes squatting/sitting on his jeans while she breastfed their 18 month old child. T Two other children who were at home, a girl of ten and a boy of seven, were about two to three meters from the source for approximately two hours. Footer 46 Imaging Day 6: Scout CT Day 6 MR Footer 47 Day 23 Day 297 Footer 48
Family Day 240: Ulcerative lesion on the lower back of the patient's wife. Day • The patient's wife showed moist desquamation, ulcerative and fibrotic lesions in the lower back after her brief exposure to the source while sitting on her husband’s jeans • No hematological changes were observed in her or her children. Footer 49 Could this happen here? Resources IAEA website – accidents and exposures • https://www.iaea.org/publications/8117/the-radiological- accident-in-nueva-aldea • Report No. 161 II - Management of Persons Contaminated With Radionuclides: Scientific and Technical Bases (2008) • NRC Event notification: https://www.nrc.gov/reading- rm/doc-collections/event-status/
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