Chapter 4: Radiation Quantities and Units Flashcards
who discovered xrays
wilhelm conrad roentgen
when was xrays discovered
November 8, 1895
how was xrays discovered
with crookes tube
First xray image
roentgens wifes hand
who was the first fatality
Clarence Dally
what was the crookes tube then updated to
Coolidge tube
who discontinued his xray research because of clarence dallys injuries and death
Thomas edison
when did clarence dally die
October 1904
Result of excessive occupational radiation exposure for early pioneers and excessive exposure of patients
Radiodermatitis
Cancer
Blood disorders
Radiodermatitis
Cancer
Blood disorders
somatic
to yourself
genetic
future generations
when were committees being started
1910
first death was 1904
best overall dose
effective dose
Early tissue reactions
nausea
fatigue
diffuse redness of the skin
loss of hair
intestinal disorders
fever
blood disorders
shedding of the outer layer of skin
Late Tissue Reactions
Cataract formation
Fibrosis
Organ Atrophy
Loss of parenchymal cells
Reduced Fertility
Sterility
Stochastic Effects
Cancer
Genetic (hereditary) effects
stochastic
random
meaning nothing is safe
nonthreshold
meaning up to a certain point, your fine after that you start seeing reactions
Threshold
Unit used from 1900 to 1930 to measure radiation exposure Problems encountered in using the skin erythema dose as a way to measure radiation exposureNeed to find a more reliable unitNew unit selected to be based on some exactly measurable effect produced by radiation, such as ionization of atoms or energy absorbed in the irradiated objec
Skin Erythema Dose
Concept of tolerance dose
Threshold dose
is recommended as a tolerance daily dose limit in 1934
0.2 R
is recommended as a tolerance daily dose limit in 1936
0.1 R
is a radiation dose to which occupationally exposed persons could be subjected without any apparent harmful acute effects, such as erythema of the skin.
Tolerance dose
radiation exposure received in the course of exercising professional responsibilities, many radiologists and dentists using the new penetrating rays developed a reddening of the skin called radiodermatitis.
occupational exposure
From 1900 to 1930, the unit in use for measuring radiation exposure was called
skin erythema dose
defined as the received quantity of radiation that causes diffuse redness over an area of skin after irradiation.
skin erythema dose
which appeared within minutes, hours, days, or weeks of the time of radiation exposure, were believed to be preventable if doses to radiation workers were limited.
early tissue reaction
that is, a dose of radiation lower than which an individual has a negligible chance of sustaining specific biologic damage.
threshold dose
A radiation dosimetry quantity that was defined by the NRC to monitor and control human exposure to ionizing radiation
Total Effective Dose Equivalent (TEDE)
Described by NRC regulations as “the sum of effective dose equivalent from external radiation exposure and a quantity called committed effective dose equivalent (CEDE) from internal radiation exposures.
36Total Effective Dose Equivalent (TEDE)
If 200 people receive an average effective dose of 0.25 Sv, the collective effective dose is
(200)(0.25)= 50 person - sieverts