Chapter 4 - Acute Radiation Syndrome

Question 1

3 things required for ARS

Answer 1

1. organism must have been acutely exposed (over the course of seconds or minutes)
2. must be exposure to total body area
3. must have externally penetrating source(s) such as x-ray, gamma ray, and/or neutrons

Question 2

What is LD50/30 and LD50/60?

Answer 2

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)

Question 3

If you increase the dose, what happens to life expectancy?

Answer 3

life expectancy decreases

Question 4

At a dose of 2 Gy (200 rad) death occurs _____ of the time?

Answer 4

a small percentage

Question 5

T/F: Survival time is not dose dependent between 1,000 R and 10,000 R.

Answer 5

true

Question 6

Survival times are dose dependent at an exposure of _______ Gy or above, lasting hours or minutes.

Answer 6

100 Gy (10,000 rad)

Question 7

Death as a result to damage to the hemopoietic system happens during what exposure range?

Answer 7

1 - 10 Gy

Question 8

Death as a result to damage to the GI system happens during what exposure range?

Answer 8

6 - 100 Gy

Question 9

Death as a result to damage to the CNS happens during what exposure range?

Answer 9

100 Gy or more

Question 10

What are the 4 ARS response stages?

Answer 10

1. Prodromal
2. Latent
3. Manifest illness
4. Recovery or death

Question 11

What are the symptoms of the first stage of ARS?

Answer 11

Prodromal: Nausea, vomiting and diarrhea

Question 12

What are the symptoms of the second stage of ARS?

Answer 12

Latent: symptom free; however changes are taking place that will either lead to recovery or death

Question 13

What are the symptoms of the third stage of ARS?

Answer 13

Manifest Illness: symptoms are dependent on which organ system is affected

Question 14

What are the symptoms of the fourth stage of ARS?

Answer 14

There are no symptoms. Either the organism recovers or dies from radiation

Question 15

What is the cause of death with the Bone Marrow Syndrome? What is the exposure range?

Answer 15

1. reduction of RBCs, WBCs, and platelets

2. 1 - 10 Gy

Question 16

What are the symptoms of the manifest stage of Bone Marrow Syndrome?

Answer 16

cytopenia (depression of all blood counts) leads to anemia and infection

Question 17

What is the cause of death with the Gastrointestinal Syndrome? What is the exposure range?

Answer 17

1. infection, dehydration, and electrolyte imbalance

2. 6 - 100 Gy

Question 18

Irradiation of what radiosensitive GI cell causes villi to lose cells and flatten out?

Answer 18

Crypts of Lieberkuhn (precursor cells to villi)

Question 19

What is the cause of death with the CNS Syndrome? What is the exposure range?

Answer 19

1. cause of death is uncertain

2. 100 Gy + (50 Gy in humans)

Question 20

Possible causes of death with CNS Syndrome are:

Answer 20

edema in the cranial vault, vasculitis, and meningitis. All can cause increased pressure in the cranial vault

Question 21

What is the expected life expectancy of CNS Syndrome?

Answer 21

few hours to a few days

Question 22

Early radiation effects on the skin include:

Answer 22

erythema, desquamation, and inflammation

Question 23

Basal skin cells eventually replace sloughed off outer layers. At what rate are skin cells replaced?

Answer 23

2% per day

Question 24

What is Skin Erythema Dose (SED)?

Answer 24

before radiation measurement units, SED was used to measure dose to skin

Question 25

What does SED50 mean and what is its value?

Answer 25

the amount of dose to the skin that would have an effect on 50% of the population. ~6 Gy

Question 26

Which is more radioresistant: fair follicles or sebaceous glands?

Answer 26

sebaceous glands. hair follicles are radiosensitive because they are actively dividing

Question 27

What is radiation cataractogenesis?

Answer 27

the formation of cataracts caused by radiation

Question 28

What is the threshold for cataractogensis? At what dose will all irradiated people get it?

Answer 28

1. 2 Gy | 2. 7+ Gy

Question 29

Doses as low as _____ Gy to the gonads cause observable responses,

Answer 29

0.1 Gy

Question 30

Define maturation depletion.

Answer 30

depletion of mature sperm due to exposure to radiation

Question 31

In males, what dose range causes temporary, 1 year sterility? What causes permanent sterility?

Answer 31

1. 2-2.5 Gy | 2. 5-6 Gy

Question 32

List the stages of ova from most radioresistant to most radiosensative.

Answer 32

small follicles, mature follicles, intermediate follicles

Question 33

A dose of ____ Gy can restrain or retard menstration.

Answer 33

0.1 Gy

Question 34

In females, what dose range causes temporary sterility? What causes permanent sterility?

Answer 34

1. 2 Gy | 2. 5-6 Gy

Question 35

What is the most radiosensitive hematologic stem cell? The least radiosensitive?

Answer 35

1. erythroblasts | 2. megakaryocytes

Question 36

What is a chromosomal aberration?

Answer 36

radiation-induced chromosomal damage that occurs BEFORE DNA synthesis; before the S phase

Question 37

What is a chromatid aberration?

Answer 37

radiation-induced chromosomal damage that occurs AFTER DNA synthesis; during the S phase