Chapter 8 Flashcards
Biologic effects of radiation that occur relatively soon after humans receive high doses of ionizing radiation
Early Effects
Not common in diagnostic imaging
Produced by a substantial dose of ionizing radiation
Early Effects
Substantial evidence of the consequences of such effects comes from numerous laboratory animal studies and data from observation of some irradiated human populations
early effects
are effects upon the body that was irradiated
somatic effects
are effects upon future generations because of irradiation of germ cells in previous generations
genetic effects
Biologic damage sustained by living organisms (such as humans) as a consequence of exposure to ionizing radiation
somatic effects
Depending upon the length of time from the moment of irradiation to the first appearance of symptoms of radiation damage, the effects are classified as either
Early somatic effects
Late somatic effects
-minutes
-hours
-days
-couple weeks
early effects
-high dose of ionizing radiation
-not common
-substantial dose
early effects
when the radiation dose is increased what happens to the biologic damage
increased biologic damage
a point at which they begin to appear and below which they are absent
threshold
Vary depending on the duration of time after exposure to ionizing radiation
Early Tissue Reactions
what does the amount of biologic damage depend on ?
The amount of biologic damage depends on the actual absorbed dose of ionizing radiatio
no tolerance
nonthreshold
tolerate up to a certain point
threshold
Appear within minutes, hours, days, or weeks of the time of radiation exposure
early tissue reactions
Requires a substantial dose of ionizing radiation to produce these biologic changes soon after irradiation
early tissue reactions
true or false
With the exception of certain lengthy high-dose-rate procedures, diagnostic imaging examinations do not usually impose radiation doses sufficient to cause early tissue reactions
true
list some high dose effects of early tissue reactions
High-dose effects include nausea, fatigue, erythema, epilation, blood disorders, intestinal disorders, fever, dry and moist desquamation, depressed sperm count in the male, temporary or permanent sterility in the male and female, and injury to the central nervous system (at extremely high radiation doses)
can result in many of these manifestations or organic damage occurring in succession (acute radiation syndrome)
Whole-body dose of 6 Gyt
Radiation sickness
ARS
Occurs in humans after whole-body reception of large doses of ionizing radiation delivered over a short period of time
ars
what does ars stand for
acute radiation syndrome
Data from epidemiologic studies of human populations exposed to doses of ionizing radiation sufficient to cause ARS have been obtained from
Atomic bomb survivors of Hiroshima and Nagasaki
Marshall Islanders who were inadvertently subjected to high levels of fallout during an atomic bomb test in 1954
Nuclear radiation accident victims such as those injured in the 1986 Chernobyl disaster
Patients who have undergone radiation therap
is a collection of symptoms associated with high-level radiation exposure
ARS
how many separate dose related syndromes occur as part of the total body syndrome
three separate dose-related syndromes occur as part of the total-body syndrome
Symptoms of ARS
-Hematopoietic syndrome (bone marrow syndrome)
-gastrointestinal syndrome
-cerebrovascular syndrome
most radiation sensitive out of the three symptoms of ARS
Hematopoietic syndrome (bone marrow syndrome
-from 1 to 10 Gy
-damage to the body
(1-2 gry recover in a couple weeks or months)
(5-6 gry w/o med = death)
Hematopoietic syndrome (bone marrow syndrome
*Appears at a threshold dose of approximately 6 Gyt and peaks after a dose of 10 Gyt
*Damage to the body
Gastrointestinal syndrome
*Results from doses of 50 Gyt or more *Damage to the body
Cerebrovascular syndrome
signs of gastrointestinal syndrome:
Severe nausea, vomiting, diarrhea, fever, fatigue, loss of appetite, lethargy, anemia, leukopenia, hemorrhage, infection, electrolytic imbalance, and emaciation
symptoms of cerebrovascular syndrome
Same as hematopoietic and gastrointestinal, plus excessive nervousness, confusion, lack of coordination, loss of vision, burning sensation of the skin, loss of consciousness, disorientation, shock, periods of agitation alternating with stupor, edema, loss of equilibrium, meningitis, prostration, respiratory distress, vasculitis, coma
symptoms of prodomal
Nausea, vomiting, diarrhea, fatigue, leukopenia