Chapter 4 - Acute Radiation Syndrome Flashcards
3 things required for ARS
- organism must have been acutely exposed (over the course of seconds or minutes)
- must be exposure to total body area
- must have externally penetrating source(s) such as x-ray, gamma ray, and/or neutrons
What is LD50/30 and LD50/60?
the lethal dose of radiation that would kill 50% of a population of an organism in either 30 days (LD50/30) or 60 days (LD50/60)
If you increase the dose, what happens to life expectancy?
life expectancy decreases
At a dose of 2 Gy (200 rad) death occurs _____ of the time?
a small percentage
T/F: Survival time is not dose dependent between 1,000 R and 10,000 R.
true
Survival times are dose dependent at an exposure of _______ Gy or above, lasting hours or minutes.
100 Gy (10,000 rad)
Death as a result to damage to the hemopoietic system happens during what exposure range?
1 - 10 Gy
Death as a result to damage to the GI system happens during what exposure range?
6 - 100 Gy
Death as a result to damage to the CNS happens during what exposure range?
100 Gy or more
What are the 4 ARS response stages?
- Prodromal
- Latent
- Manifest illness
- Recovery or death
What are the symptoms of the first stage of ARS?
Prodromal: Nausea, vomiting and diarrhea
What are the symptoms of the second stage of ARS?
Latent: symptom free; however changes are taking place that will either lead to recovery or death
What are the symptoms of the third stage of ARS?
Manifest Illness: symptoms are dependent on which organ system is affected
What are the symptoms of the fourth stage of ARS?
There are no symptoms. Either the organism recovers or dies from radiation
What is the cause of death with the Bone Marrow Syndrome? What is the exposure range?
- reduction of RBCs, WBCs, and platelets
2. 1 - 10 Gy
What are the symptoms of the manifest stage of Bone Marrow Syndrome?
cytopenia (depression of all blood counts) leads to anemia and infection
What is the cause of death with the Gastrointestinal Syndrome? What is the exposure range?
- infection, dehydration, and electrolyte imbalance
2. 6 - 100 Gy
Irradiation of what radiosensitive GI cell causes villi to lose cells and flatten out?
Crypts of Lieberkuhn (precursor cells to villi)
What is the cause of death with the CNS Syndrome? What is the exposure range?
- cause of death is uncertain
2. 100 Gy + (50 Gy in humans)
Possible causes of death with CNS Syndrome are:
edema in the cranial vault, vasculitis, and meningitis. All can cause increased pressure in the cranial vault
What is the expected life expectancy of CNS Syndrome?
few hours to a few days
Early radiation effects on the skin include:
erythema, desquamation, and inflammation
Basal skin cells eventually replace sloughed off outer layers. At what rate are skin cells replaced?
2% per day
What is Skin Erythema Dose (SED)?
before radiation measurement units, SED was used to measure dose to skin
What does SED50 mean and what is its value?
the amount of dose to the skin that would have an effect on 50% of the population. ~6 Gy
Which is more radioresistant: fair follicles or sebaceous glands?
sebaceous glands. hair follicles are radiosensitive because they are actively dividing
What is radiation cataractogenesis?
the formation of cataracts caused by radiation
What is the threshold for cataractogensis? At what dose will all irradiated people get it?
- 2 Gy
2. 7+ Gy
Doses as low as _____ Gy to the gonads cause observable responses,
0.1 Gy
Define maturation depletion.
depletion of mature sperm due to exposure to radiation
In males, what dose range causes temporary, 1 year sterility? What causes permanent sterility?
- 2-2.5 Gy
2. 5-6 Gy
List the stages of ova from most radioresistant to most radiosensative.
small follicles, mature follicles, intermediate follicles
A dose of ____ Gy can restrain or retard menstration.
0.1 Gy
In females, what dose range causes temporary sterility? What causes permanent sterility?
- 2 Gy
2. 5-6 Gy
What is the most radiosensitive hematologic stem cell? The least radiosensitive?
- erythroblasts
2. megakaryocytes
What is a chromosomal aberration?
radiation-induced chromosomal damage that occurs BEFORE DNA synthesis; before the S phase
What is a chromatid aberration?
radiation-induced chromosomal damage that occurs AFTER DNA synthesis; during the S phase