exposure of a few minutes and many hundreds or thousands of rads
total body exposure
what is LD 50/30?
half of the population exposed will die in 30 days
what are the two stages of acute radiation syndrome (ars)?
prodromal
latent
what is the prodromal stage of ARS?
initial stage
50 rads
matter of minutes
NVD
what is the latent stage of ARS?
individual appears symptom free
recovery or lethal effect is based on dose
what are the two final stages of ARS?
manifest- illnesses begin to show
recovery or death
What are some stages of manifest illness?
hematologic/hematopoietic syndrome
gastrointestinal syndrome
central nervous syndrome
LD 50/30
Describe the hematologic/hematopoietic syndrome
occurs at lower dose levels
100-1000 rads
sensitive individuals die within 6-8 weeks following a dose of 200 rads
no one has ever lived after a dose of 1000 rads
the first stage will be NVD
a latent period can extend from a few hours to 4 weeks
what happens during the latent period of hematologic/hematopoietic syndrome?
RBC's, WBC's and platelet counts begin to decline
the mitotic cells have been sterilized
the lowered cell counts is known as pancytopenia
symptoms include fever, general malaise, anemia, hemorrhage, and infection
death may result from dehydration, electrolyte imbalance, or infection
at what range does the hematologic/hematopoietic syndrome occur?
100-1000 rads
at what range does gastrointestinal syndrome occur?
600-1000 rads
what are the prodromal and latent periods for GI syndrome?
prodromal: app. 1 day (1st wave of NVD)
latent: 3-5 days
what is the manifest illness of GI syndrome?
2nd wave of NVD
What happens to the GI tract during the manifest illness of GI syndrome and what causes this??
lining of GI tract is being removed (lined w/ epithelial cels which are very sensitive to rad because they divide alot
-results in dehydration
-medical intervention cannot stop the progression of this syndrome
-death usually results within 3-4 days
At what range does central nervous syndrome occur?
around 5000 rads
What happens in a central nervous syndrome?
death occurs within hours
hematopoietic and GI syndrome occur simultaneously
what are the symptoms of central nervous syndrome?
loss of muscle control - ataxia
convulsions
difficulty breathing
coma
why do oxygenated cells recover better than hypoxic cells?
because there's more oxygen that can repair the damage but also cells that have more oxygen are more sensitive to radiation
*i.e- a cut on the face will recover quicker than a cut on the foot because there's more blood circulation in the face
when is it possible for repair and recovery to occur and how does it do this?
possible at sublethal doses
cells carry an inherent repair mechanism
surviving cells will begin to repopulate
this permits damaged organs to regain some functional ability
what is local tissue damage?
results from high doses just to parts of the body and not the whole body
full, partial or no recovery of local tissue damage from radiation depends on what?
the dose and organ cell type that is irradiated
necrosis occurs in nonrecovery
what is another term for skin damage caused by radiation?
radiodermatitis
why is the skin extremely sensitive to radiation?
cells are constantly renewing
about 2% of the skin is replaced each day
which cells of the skin get the most damage from radiation?
germ (basal) cells
true or false, skin effects are non-linear, non threshhold
false
it is non-linear but there is a threshold because skin erythema (radiodermatitis) has a threshold which is 150 rads
what is epilation?
hair loss
true or false: gonads are extremely sensitive to radiation
true
true or false: stem cells of the ovaries multiply in fetus then number then begins to decline
true
true or false testes stem cells are not constantly renewing
false
they constantly renew
which cells of the testes, mature or immature, divide rapidly and which do not?
mature- are specialized and do not divide rapidly
immature- are unspecialized and divide rapidly
how many rads does it take to cause a reduction in spermatozoa?
10
how many rads for temporary sterility in men and women?
200
can least up to one year
how many rads for permanent sterility for men. What about for women?
500-600 rads for men
500 rads for women
true or false; the ova are comprised of mature cells and they divide rapidly
true
how many rads does it take to cause a hematologic depression?
25 rads
which cells are the most sensitive to radiation lymphocytes or erythrocytes? what is its life span?
lymphocytes
few days to 4 months
which cells are the least sensitive to radiation lymphocytes or erythrocytes? what is its life span?
erythrocytes
4 months
list all of the radiation guidlines given by Dr. M.K. Kassabian dealing with patient protection
only small interrupted doses should be given
high gas tubes produce less radiodermatitis than low gas tubes
the more distance from the tube, the less danger of burning the pt
screen surrounding parts of the body with thin sheets of lead
the soft and unnecessary x-rays should be filtered by leather or aluminum
list all of the radiation guidlines given by Dr. M.K. Kassabian dealing with operator protection
never use the hands to test the intensity of x-rays
the operator should be ina communicating room while the pt is undergoing treatment or examination; he or she should be behind lead and be able to observe the fluorescence of the tube
the best place for lead protection is behind the anode
wherever x-rays may be detected (by electroscope or photographic plate) is unsafe for the operator
opaque lead rubber gloves, aprons to prevent injury to the gonads, and lead glass spectacles should be worn for added protection
