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98 terms

Physics II Chapter 35&36

STUDY
PLAY
1920 and 1930's
radiologic techs have weekley blood work to check thier levels of radiation;no film badges back then
death
the most devastating of all the responses to radiation;there have been no documeneted cases other than early pioneers(they all died of late effects)
acute radiation
induced human lethality is only of ACADEMIC INTEREST in diagnostic radiation;diagnostic beams are not intense enough or large enough to cause death
Chernobyl
an incident that happened in 1986 where 30 people died from acute radiation syndrome;also alot of late effects
acute radiation syndrome
the sequence of events following a high-level radiation exposure leading to death within days or weeks
prodromal period
doses above 100cGy to the whole body with symptoms in mins or hours; symptoms are Nausea,Vomitting;Diarrhea;Decrease in white blood cells
latent period
the period of well being after the radiation sickness;can last for hours or less;thought to be a recovery period but can be misleading as more may follow
hematologic syndrome (least worst)
doses between 200-1000 cGy; appear within a few HOURS and last for a few DAYS
hematologic syndrome symptoms
symptoms are vomiiting,diarrhea,malaise,lethargy and fever; reduced wbcs,rbcs and platelets
hematologic syndrome lasting time
the latent period usually last a few weeks;2-4 week recovery and up to 6 months for full recovery
gastrointestinal syndrome
doses from 1000-5000cGy;occur within hours
gastrointestinal syndrome symptoms
symptoms are same as hematologic plus electrolyte imbalance,shock and fatique
gastrointestinal syndrome lasting time
latent period is 3-5 days;manifest begins with a second wave of symptoms,death ultimately occurs within 4-10 days ;the lower dose you recieve the longer you live
central nervous system (worst one)
dose exceeds 5000cGy;symptoms occur and lead to death within hours/days
the 3 syndromes
hematolgic syndrome, central nervous system syndrome,gastrointestinal syndrome
central nervous system symptoms
symptoms are same as GI plus ataxia,edema,vasculitis,meningitis
central nervous system lastime time
signs start in 15 minutes,death wihin 48 hours,death is always the result
LD 50/60
dose of radiation to the whole body that causes 50% of subjects to die within 60 days;if death is to occur it happens within 60 days
the acute radiation lethality is
350 cGy for humans
mean survival time
as the whole body dose increases the average time between exposure and death decreases
LD 50/60 for humans is
350 rad
a whole body dose equivalent of 3000 rem (30 sv) would cause death in 4 to 10 days in which mechanism
gastrointestinal death
Ld 50/30
lethal dose to the total body radiation for 50% of the people exposed in 30 days
cytogenetic damage
considered an early response to radiation exposure
Ld 50/60 represents the dose
that will kill half the people in 60 days
non-linear threshold
applied to both ovaries and will induce permanent sterility
the acute syndrome consist of all the following except
latent injury syndrome
the acute radiation syndrome
by gastrointestinal death indicates a mean survival time of about 4 to 10 days
death caused by a single dose of total body irridation primarily involves damage
bone marrow
early effects of radiation
have very high exposures
late effects of radiation
have lower exposures over a long period of time
the exposures in diagnostic radilogy
are low and of low (LET)
late effects of radiation
induced malignancy and genetic effect
lost late effects are known as
stochastic
alpha particle
high LET
photon and electron
low LET
epidemiologic studies
studies of large numbers of people exposed to toxic substances
studies are diffuicult because
dose is usually unknown and frequency response is low
which of the follwing dose-response relationships best describes radiation induced lung cancer
linear, non threshold
which of the following numbers approximates the total cases of leukemia observed in the 100,000 atomic bomb survivors
150
the latent period of radiation induced leukemia is considered to be
4 to 7 years
analysis of the survivors of the atomic bomb shows that the induction of leukemia
supports a linear, nontreshold dose-response relationship
which of the following populations has shown an increased incidence of leukemia after radiation exposure
atomic bomb surviors
which of the follwing types of cancer has not been demonstrated in humans after irradiation
colon
which type of radiation-induced cancer exhibits a threshold dose-response relationship
skin
the radiation dose-response relationship for genectic mutations is
linear
the relative risk of leukemia after irradiation in utero
would equal 1.0 if thier were no risk
radiation induced leaukemia
has been demonstarted both in animals and humans
the general accepted absolute risk factor for radiaton induced breast cancer is
6 cases/10^6/rad/yr
the relative risk of leaukemia after low dose radition in utero is approximately
1.5
when engaged in a busy fluoroscopy schedule who should wear protective lens shields
neither radiologist or technologist
which of the follwing is the greatest loss of life expectancy
being male
the average latent period for radiation induced cataracts is
15 years
epidemilogy is the study
populations
radiation induced cataracts
follow a non-linear threshold type of dose response relationship
which of the follwing groups has suffered a harmful radiation effect
radium watch dial painters
supporting evidence for radiation carcinogenesis comes from
fluoroscopic monitoring of patients with tuberculosis
diagnostic x-rays have been shown to produce which of the following
chromosome aberrations
which of the follwing statements about radiation-induced cataracts after CT examinantion of the head is most appropriate
the dose is probably in the neighborhood of the treshold for such an effect of
which of the following is an example of a linear, nonthreshold, dose-response relationship
leukemia
linear dose response relationship
must be assumed to be non-threshold than only one dose level is required
radiohormesis
a little bit of radiation is good
relative risk of 1
represents no risk at all
absolute risk estimates
units are a number of 10cases/10^6 persons/rad/year
excess risk estimates
leukemia incidence in an irradiated population exceeds that which is expected then it is the differece between the observed number and the expected number
relative risk estimates
estimating late radiation effects in large populations without having any precise knowledge of thier radiation dose
atomic bomb survivors
no life span shortage observed
radilogic technology
considered a safe occupation
radiation workers reduced life span
12 days
occupational accident life span
74 days
humans reduced life span
10 days for every rad
radiation induced cataracts occur on the
posterior pole of the lens of the eye
5 radiation induced cataracts conclusions
age dependent;the older the person the greater the radiation effect;latent periods have been observed as 5 to 30 years but are an average of 15 years;high LET such as neutrons and protons have a high rbe for cataracts
cyclotron
developed in 1932 by EO Lawrence at the University of California ;produced radionuclides like F-18 for PET imaging
cataracts
appeared in 1949 and by 1960 over 100 cases were reported
local tissue effects (CATARACTS)
physicist looking directly into a cyclotron high energy beam
late effects (CHROSOMES)
leukemia,chromosome damage in the lymphocytes,ovarian cancer and neuroblastoma
late effects (SKIN)
skin cancer and radiodermatitis seen years ago
early efects (CHROSOMES)
hematological depression,chromosome damage with reduced WBC's
early effects (SKIN)
erythema,desquamation
induced malignancys
leukemia,thyroid cancer,skin,breast and lung cancer
elevated incidence of leukemias
a bomb survivors,american radilogist,radiotherapy patients and children in utero
thyroid cancer (first two groups)
Ann Arbor and Rochester treated for enlarged thymus glands due to infection during 1940-1950
skin cancer
begins with radiodermatitis,latent period of 5-10 years;as dose increases so does absolute risk factors
thyroid cancer (third group)
Rongelap Atoll in 1954; Abomb testing with wind-shifts
bone cancer (first group)
radium watch dial painters that touched the brush to thier tounges and ingested radium
breast cancer
TB patients developing this after flouro,10:1 risk created;patients faced the radilogist so the beam entered posterior recived low doses ,fluoro from front higher breats cancer
bone cancer (second group)
group treated with radium salts for various diseases from TB to Arthritis,common in the 1950's
lung cancer
50% of all bohemian pitch blade miners in Germany died due to Radon in the mines;same for the miners in Colorado plateau in teh 1950's filled with Uranium Ore
radon in lung
decays to lead once in the lung
total risk malignncy
400 deaths from radiation induced malignancy after an exposure of 1 RAD to 1,000,000 persons when all such cases occuring with 25 years of exposure are counted
three mile island
1970, 2 million inhabitants of the island over a 50 mile radius, 330,000 cancer cases reported
natural cancer deaths
400,000 should occur anway
radiation and pregnancy
high level radiation effects do exist and it is dose related,more dose to fetus more problems
radiologist offspring
suggest an increase in congenital abnormalites and depressed fertility but the study has problems
first trimester
most radiosensitive,first 10 days
doubling dose
50 to 250 rads;dose of radiation that will produce twice the frequency of genectic mutations as would have been observed with radiation
radiation induced chromosome abbreations are which of the following
early and late effects