Article Figures & Data
Figures
- FIGURE 1.
This figure shows dose curves that correspond to dose models described in text. Data are measured at high dose levels and then, using curve-fitting techniques, extrapolated to estimate low-dose portion of curve. Low-dose data points shown on these curves are thus estimated, not measured.
Tables
H2O (molecule) + ionizing radiation → H+ + OH− = (hydroxyl, free radical) Recombination of: H+ + H+ → H2 = hydrogen gas (not a problem) H+ + OH− → H2O = water (not a problem) Antioxidants can recombine with the OH− free radical and block hydrogen peroxide formation. If not, then the 2 hydroxyl ions could do the following: OH− + OH− → H2O2 = hydrogen peroxide formation H2O2 → H+ + HO2− = unstable peroxide HO2− + organic molecule → stable organic peroxide Stable organic peroxide → lack of essential enzyme → eventual cell death is possible Syndrome Summary Hematologic Dose: Approximately 1–10 Gy (100–1,000 rad) Clinical symptoms: General injury of blood-forming cells in bone marrow, which increases with increasing dose, leading to pancytopenia. This results in bleeding, anemia, hemorrhage, malaise, and severe, often fatal, infection. Treatment: 0–1 Gy (0–100 rad)—Reassurance 1–2 Gy (100–200 rad)—Reassurance and hematologic surveillance 2–6 Gy (200–600 rad)—Blood transfusion and antibiotics 6–10 Gy (600–1,000 rad)—Consider bone marrow transplant Without treatment, no one has survived a single abrupt dose of 5 Gy (500 rad) or higher. It is possible to survive the hematologic syndrome with a bone marrow transplant, but at higher doses all subjects will die from the gastrointestinal syndrome. Gastrointestinal Dose: Approximately 2–50 Gy (200–5,000 rad) Clinical symptoms: Nausea, vomiting, and diarrhea; prolonged diarrhea; dehydration; electrolyte imbalance; lethargy; anorexia; death above 10 Gy (1,000 rad) with no treatment. Treatment: 2–6 Gy (200–600 rad)—Blood transfusion and antibiotics 6–10 Gy (600–1,000 rad)—Consider bone marrow transplant 10–50 Gy (1,000–5,000 rad)—Maintenance of electrolyte balance At about 2 Gy (200 rad), classic radiation sickness (nausea, vomiting, and diarrhea) may begin because of radiation injury to the gastric and intestinal mucosa. Central nervous system Dose: >50 Gy (>5,000 rad) Clinical symptoms: Ataxia, convulsions, lethargy, coma, death Treatment: Sedatives Species LD50/30 Cockroach 50 Gy (5,000 rad) Rabbit 8 Gy (800 rad) Goldfish 7.5 Gy (750 rad) Rat 6 Gy (600 rad) Mouse 4.5 Gy (450 rad) Monkey 4.5 Gy (450 rad) Human ∼2.5–4.5 Gy (250–450 rad) Radiation exposure range Therapeutic Lethal Parameter Subclinical (0–1 Sv [0–100 rem]) 1–2 Sv (100–200 rem) 2–6 Sv (200–600 rem) 6–10 Sv (600–1,000 rem) 10–50 Sv (1,000–5,000 rem) >50 Sv (>5,000 rem) Treatment required Reassurance Reassurance and hematologic surveillance Blood transfusion and antibiotics Consider bone marrow transplant Maintenance of electrolyte balance Sedatives Overall treatment plan None needed Observation Effective Therapy promising Palliative Palliative Incidence of vomiting None 5% at 1 Sv (100 rem); 50% at 2 Sv (200 rem) 100% at 3 Sv (300 rem) 100% 100% 100% Delay time prior to vomiting N/A 3 h 2 h 1 h 30 min 30 min Leading organ affected None Blood-forming tissue Blood-forming tissue Blood-forming tissue Gastrointestinal tract Central nervous system Characteristic signs None Mild leukopenia Severe leukopenia; hemorrhage; hair loss above 3 Sv (300 rem) Severe leukopenia; infections; erythema Diarrhea; fever; electrolyte imbalance Convulsions; tremor; ataxia; lethargy Critical period after exposure N/A N/A 4–6 wk 4–6 wk 5–14 d 1–48 h Prognosis Excellent Excellent Good Guarded Hopeless Hopeless Incidence of death None None 0%–80% 80%–100% 90%–100% 90%–100% Cause of death N/A N/A Hemorrhage and infection Hemorrhage and infection Circulatory collapse Respiratory failure and brain edema Phase Description Prodromal (“running before”) Signs and symptoms include nausea, vomiting, and diarrhea; hair loss above 3 Gy (300 rad); skin erythema above 6 Gy (600 rad) Latent Period of no signs or symptoms Manifest Nausea, vomiting, and diarrhea return; hematologic syndrome; gastrointestinal syndrome; central nervous system syndrome; signs and symptoms return to prodromal levels or worse Recovery If good treatment is provided and the affected individual received less than a 10-Gy (1,000-rad) dose, recovery is possible after the manifest phase - TABLE 6
Average Annual Effective Dose Equivalent to a Member of the U.S. Population (14,16)
Source Effective/whole-body dose Average annual dose to U.S. population from all sources 6.2 mSv (0.62 rem) Radon & thoron 2.28 mSv (0.228 rem) Conventional radiography & fluoroscopy 0.33 mSv (0.033 rem) Computed tomography 1.47 mSv (0.147 rem) Nuclear medicine 0.77 mSv (0.077 rem) Consumer products 0.13 mSv (0.013 rem) Cosmic radiation 0.33 mSv (0.033 rem) Terrestrial radiation 0.21 mSv (0.021 rem) Radiopharmaceutical cGy/mCi (rad/mCi) 67Ga-citrate 0.26 201Tl-chloride 0.21 18F-FDG 0.04 123I-iodide 0.03 99mTc-sulfur colloid 0.019 99mTc-MIBI 0.017 99mTc-DTPA 0.016 99mTc-DISIDA 0.016 99mTc-MAA 0.015 99mTc-HMPAO 0.013 99mTc-pertechnetate 0.011 99mTc-MDP 0.007 99mTc-MAG3 0.007 Region of body Annual limit in cSv (rem) Whole body 5 Extremities (hand, forearm) 50 Skin 50 Any internal organ 50 Lens of the eye 15 Cumulative lifetime dose = 1 cSv (rem) × age. Fetal dose = 0.5 cSv (rem)/9 mo, not to exceed 0.05 cSv (rem)/mo. General public in nonrestricted areas = 0.002 cSv (rem)/h or 0.1 cSv (rem)/y.
