Radiation Injuries Tintinalli Chap. 11

1. Radiation InjuriesTintinalli Chap. 11

2. Radiation Injuries • Sources of a radiation event • Accidental • Any facility utilizing a radioactive source • During transport of radioactive materials • Erroneous dosing of radiotherapy • Exposure during theft of radioactive sources • Unknown exposure • Dumpster divers • Intentional • “Dirty bomb” • Attack on a nuclear installation • Nuclear weapons

3. Incidence of Radiaton Events • Radiation Emergency Assistance Center/ Training Site (REACTS) registry • Data beginning in 1944 • 426 radiation accidents worldwide • Most are high-dose local exposure in the industrial setting • 133,811 victims (most from Chernobyl) • 3,063 with significant exposure • 134 fatalities

4. Chernobyl • Occurred in 1986 • 116,500 victims • 28 acute fatalities

5. Types of Radiation Nonionizing Ionizing Alpha Particles Beta Particles Neutrons X-rays Gamma waves • Ultraviolet rays • Visible light rays • Infrared rays • Microwaves • Radio waves • Lasers • Ultrasound • Nuclear MR

6. Ionizing Radiation • Refers to the ability of high-energy radiation to displace electrons from atoms and cause matter through which it passes to become electrically charged • Types • Particles • Alpha Particles • Heavy and highly charged • Deposit large amount of radiation into small amount of tissue • Significant biological hazard only when internalized • Easily shielded and unable to penetrate paper or keratin layer of skin • Sources include uranium and plutonium

7. Ionizing Radiation • Beta Particles • Smaller mass and charge • Can travel several meters in air • Penetrates ~ 8mm into exposed skin • Hazard only if internalized • Neutrons • Electrically neutral • Wide range of energy, velocity, and penetration power • Exposure can induce stable atoms in the absorbing material to become radioactive • NA-24 in human tissue • Sources include nuclear power plants, particle accelerators, and weapon assembly sites

8. Ionizing Radiation • Waves • Electromagnetic waves travelling at the speed of light • No mass or charge • Exposure presents a whole-body radiation hazard and may result in acute radiation syndrome • Shield with lead or concrete • X-rays • Gamma rays • Most penetrating type of ionizing radiation • Can travel several meters in air and several centimeters into tissue

9. Units of Measure • Activity • Describe the amount of radioactivity present • Rate of decay or disintegrations per second • Curie (Ci), Becquerel (Bq) • Exposure • Amount of x-ray or gamma radiation that produces a given number of ionizations in air • Roentgen (R), Coulombs per kg • Absorbed Dose • Amount of energy the radiation imparts to matter through which it passes • Rad (r), Gray (Gy) • Dose Equivalent • Common scale of measurement for different types of radiation • Rem; Sievert (Sv) • 1 rad alpha radiation = 20 rem • 1 rad beta, gamma, or x-ray radiation = 1 rem • Body Burden • Amount of radiation delivered to the body from internally deposited radioactive material • Maximum Permissable Body Burden (MPBB) • Amount of radioactivity that may be present in the body for a working lifetime and pose no reasonable expectation of health risk

10. Biologic Effect of Ionizing Radiation • DNA • Directly ionized or indirectly damaged • Cell death • Damage of cell’s mitotic capability • Rapidly proliferating cells are most radiosensitive • Hematopoietic • Gastrointestinal • Reproductive systems

11. Monitoring Equipment • Dosimeters (Film badge) • Small devices worn on the upper torso • Record cumulative amount of radiation an individual receives while wearing the device • Survey Meters • Record the amount of radiation detected in an area per unit of time • Geiger-Müeller (GM) instruments

12. Radiation Event Management • Advance Planning • HazMat • JCAHO requires every hospital to have written protocol for receiving and treating victims • Prehospital Emergency Medical Management • Secure the Scene • Identify the hazard • Personal Protective Equipment • Dosimeter/Survey meters • Communicate with hospital

13. Radiation Event Management • ED Notification • Circumstances of the event • # of victims • Medical condition and physical injuries of the victims • Type and extent of radiologic insult • Externally or internally contaminated • Identification of the radioactive material • Were the victims surveyed • Exposure to other hazardous material

14. Radiation Event Management • Activation of the Plan • Identify members of the Radiation Response Team • Determine individual responsibilities • Location and type of radiation emergency supplies • Dosimeters/survey meters • Resuscitation equipment and trauma supplies • Specimen containers • Portable ultrasound • Procedures to ensure ED staff and patient safety • Establish Radiation Emergency Area (REA) • Isolate from common areas • Secure access • Surround with “buffer zone”

15. Radiation Event Management • Triage and Treatment Philosophies • Goal is to limit exposure and contain spread • Medical condition takes priority over decontamination • If medically stable prioritize by type of exposure • Externally contaminated • Radioactive material deposited on skin • Internally contaminated • Ingestion, absorption, or inhalation of radioactive materials • Externally irradiated • All or part of the body is exposed to a penetrating radiation source

16. Externally Contaminated • Dose is rarely significant • Main hazards are spreading the contamination and potential of internalization • Decontamination • Remove clothing and place in a plastic bag • May remove up to 90% • Decontaminate • Resurvey

17. Local Radiation Injury • Represents most radiation accidents in U.S. • Rarely causes systemic manifestations • Usually consist of cutaneous changes similar to thermal burn • First week • Asymptomatic or transient erythema, hyperesthesia, and itching • Second week • True erythema with progressive epilation • Third week • Skin becomes warm, painful, swollen, and pruritic • Fourth week • Dry or wet desquamation and/or ulceration • Treat with analgesics, routine burn care, and close follow-up

18. Whole-Body Irradiation/Acute Radiation Syndrome • Whole body gamma dose in excess of 2 Gy (200 rad) • Occurs in phases • Prodromal phase • Within minutes, hours, or days of exposure • GI symptoms including anorexia, N/V, and diarrhea • Neuromuscular symptoms including hypotension, pyrexia, diaphoresis, cephalgia, and fatigue • Latent phase • symptom-free interval lasting hours to weeks • Manifest illness phase • 3 dose-dependent subsyndromes • Hematopoietic Syndrome • Gastrointestinal Syndrome • Cardiovascular and Central Nervous Syndrome

19. Hematopoietic Syndrome • Radiation destroys circulating lymphocytes and damages stem cells in the bone marrow and lymphatic system • First system to manifest injury • Symptoms above 1.5-2 Gy (150-200 rad) • Hallmark is rapid decline in lymphocytes • Results in pancytopenia and immunosuppression placing patient at risk for hemorrhage and infection

20. Gastrointestinal Syndrome • Damage of the intestinal mucosa results in massive fluid losses and entry of enteric flora into the bloodstream • Occurs at doses above 6-7 Gy (600-700 rad) • Symptoms occur within hours of exposure • N/V • Diarrhea • Few documented cases, all fatal

21. Cardiovascular and Central Nervous System Syndrome • Occurs after doses above 20-30 Gy (2000-3000 rad) • Symptoms include prostration, N/V, explosive bloody diarrhea, persistent hypotension, lethargy, disorientation, ataxia, tremors, and convulsions • Universally fatal within 24-72 hours

22. Management of Whole-Body Irradiation • Alleviate symptoms • Antiemetics • Anxiolytics • Analgesics • Type and cross • Serial blood draws (lymphocyte decline) • Supportive therapy • IV fluids • Blood transfusion • TPN • Reverse isolation • Prophylactic antibiotics

23. Internally Contaminated • Inhalation, ingestion, or absorption • Sources • nuclear weapon detonation • Large-scale nuclear power plant accident • Volcanic eruption • Labs • All body excreta should be collected for several days to monitor elimination rates • Treatment • Irrigate all wounds • If inhaled, consider bronchopulmonarylavage • If ingested, consider gastric lavage, antacids containing aluminum, and cathartics

24. Specific Agents • Radioiodine (I-131) • Hazardous to thyroid • Potential risk of causing hypothyroidism and thyroid cancer • Detected in urine immediately after exposure • Treatment • Potassium iodine (KI) • Give within 12 hours of exposure • 90% effective if given within 1 hour • Antithyroid meds (PTU, methimazole) • After 12 hours post-exposure • Plutonium (Pu-239) (alpha contamination) • Treat with chelating agents • Ca-DTPA • Preferred agent for initial 1-2 days • Zn-DTPa • Prolonged use and pregnant females