Chapter 33: Deterministic Effects Of Radiation

Question 1

To produce a radiation response in humans within a few days to months, the dose must be substantial.
Such a response is called an ______

Answer 1

early effect of radiation exposure

Question 2

To produce a radiation response in humans within a few days to months, the dose must be _____

Answer 2

substantial

Question 3

A dose of this magnitude is rare in diagnostic radiology

Answer 3

Deterministic effects of radiation

Question 4

Radiation response that exhibit increasing severity with increasing radiation dose

Answer 4

Deterministic Radiation Response

Question 5

the most devastating human response to radiation exposure

Answer 5

Death

Question 6

In deterministic effect, there is a dose threshold, and the dose- response relationship is _____.

Answer 6

nonlinear

Question 7

is of only academic interest in diagnostic radiology.

Answer 7

Acute radiation-induced human lethality

Question 8

are neither intense enough nor large enough to cause death.

Answer 8

Diagnostic x-ray beams

Question 9

– April 1986
– 30 people experienced the acute radiation syndrome and died.
– A number of minor late effects have been observed

Answer 9

Chernobyl Nuclear Accident (Ukraine)

Question 10

– March 1979
–No one died or was even seriously exposed

Answer 10

Nuclear power reactor incident at Three Mile Island, Pennsylvania

Question 11

– March 2011
– No acute lethality was observed

Answer 11

Tsunami-induced nuclear reactor meltdown at Fukushima, Japan

Question 12

– The sequence of events that follow high-level radiation exposure
leading to death within days or weeks.

Answer 12

Acute Radiation Syndrome

Question 13

There are, in fact, three separate syndromes that are dose related and that follow a rather distinct course of clinical responses. These are:

Answer 13

Hematologic death
Gastrointestinal death
CNS death

Question 14

• In addition to the three lethal syndromes, two periods are associated with acute radiation lethality:

Answer 14

Prodromal period
Latent period

Question 15

Death that requires radiation doses in excess of 50 Gyt (5000 rad) and results in death within hours

Answer 15

CNS Death

Question 16

Deaths that follow lower exposures and require a longer time for death to occur

Answer 16

Hematologic death
GI Death

Question 17

–Consists of acute clinical symptoms that occur within hours of
exposure and continue for up to a day or two.

Answer 17

Prodromal period

Question 18

– Subject is free of visible effects.

Answer 18

Latent period

Question 19

The immediate response of radiation sickness is the ____

Answer 19

prodromal period

Question 20

The _____ period may last from a few hours to a couple of days.

Answer 20

prodromal

Question 21

• After the period of initial radiation sickness, a period of apparent well-being occurs, which is called the _____ period.

Answer 21

latent

Question 22

Very high radiation doses, the latent period _____ altogether.

Answer 22

disappears

Question 23

Very low radiation doses, there may be ______ at all.

Answer 23

no prodromal period

Question 24

• It is characterized by a reduction in white cells, red cells & platelets.
• Approximate Dose: – 200-1000 rad

Answer 24

HEMATOLOGIC SYNDROME

Question 25

Latent Period:
– General feeling of wellness
• Period of Manifest illness:
–Vomiting, mild diarrhea, malaise, lethargy &
fever
• Recovery:
– 2-4 weeks or 6 months (full)
• Cause of Death:
– Generalized infection, electrolyte imbalance & dehydration

Answer 25

Hematologic syndrome

Question 26

occurs principally because of severe damage to the cells lining the intestines.

Answer 26

GI death

Question 27

Approximate Dose: – 1000-5000 rad
• Mean Survival Time: – 4-10 days
• Clinical S&S:
– Same as hematologic plus electrolyte imbalance, lethargy, fatigue & shock

Answer 27

GI Syndrome

Question 28

Prodromal Period:
– Vomiting & diarrhea
• Latent Period:
– No symptoms present
• Period of Manifest Illness:
– Second wave of nausea &
vomiting,
– Unprevented rapid progression of symptoms

Answer 28

GI Syndrome

Question 29

Its ultimate cause is elevated fluid content of the brain.

Answer 29

CNS Syndrome

Question 30

Characterized By:
– Increased intracranial pressure, vasculitis & meningitis
• Approximate Dose:
– > 5000 rad
• Mean Survival Time:
– 0-3 days
• Clinical S&S:
– same as GI plus ataxia, edema, system vasculitis & meningitis

Answer 30

CNS Syndrome

Question 31

Prodromal Period:
– Severe nausea & vomiting
• Latent Period:
– Earlier symptoms disappear
• Period of Manifest Illness:
– More severe prodomal
disoriented, loss muscle
dyspnea, convulsive seizures, loss of equilibrium, ataxia & lethargy.

Answer 31

CNS Symptom

Question 32

The whole body radiation dose that causes 50% of irradiated subjects to die within 60 days

Answer 32

LD 50/60

Question 33

Acute radiation lethality follows a what dose response relationship

Answer 33

Nonlinear, threshold dose-response relationship

Question 34

is dose dependent with the hematologic syndrome.

Answer 34

Mean survival time

Question 35

The tissue with which we have had the most experience is the.

Answer 35

skin

Question 36

are the stem cells that mature as they migrate to the surface of the epidermis.

Answer 36

Basal cells

Question 37

is known as clinical tolerance for radiation therapy.

Answer 37

Moist desquamation

Question 38

was perhaps the first observed biologic response to radiation exposure.

Answer 38

Erythema

Question 39

For many years, soft x-rays (10–20 kVp), called _____, were used as the treatment of choice for persons with skin diseases, such as tinea capitis (ringworm).

Answer 39

grenz rays

Question 40

Germ cell development

Answer 40

Gametogenesis