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What date did Roentgen discover x-ray?
November 8, 1895
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Where did Roentgen discover x-ray?
the University of Wurzburg in Barvaria
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What was Roentgen working on when he discovered x-ray?
Crookes tube
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What year does the first reports of injury date back to(in Europe)?
1896
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Who was the first fatality of radiation? What year did this occur?
- Clarence Madison Daily(glassblower, tube maker, assistant, and long-time friend of fluoroscope inventor-Thomas Edison)
- October 1904
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Deaths of physicians who worked with radiation were reported as early as what year?
1910
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What did the first occupational exposure injuries lead to?
- Radiodermatitis(which often developed into cancer)
- Aplastic anemea(results from bone marrow failure)
- Leukemia(overproduction of white blood cells)
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The British X-Ray and Radium Protection Committe was formed in what year?
1921
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This committee was formed to investigate methods to reduce radiation exposure.
The British X-Ray and Radium Protection Committee (1921)
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What was the outcome of the British X-Ray and Radium Protection Committe?
They were unable to determine a workable unit of measuring radiation, therefore, they were unsuccessful at reducing exposure to radiation.
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When was skin erythema dose the unit of measurement for radiation exposure?
1900-1930
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What determined the dose recieved for skin erythema dose?
The degree of reddening (remember different skin types will react differently to radiation exposure)(to have the same erythema dose someone naturally dark would need more radiation exposure than someone with very light skin)
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What year did the First International Congress of Radiology meet?
1925
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Why was the First International Congress of Radiology so significant?
It allowed, for the first time, for all radiologist around the world to collaborate
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The International Commission on Radiation Units and Measurements (ICRU) was formed in what year?
1925
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What year was the Second International Congress of Radiology formed?
1928
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The ICRU was delegated to define the unit of radiation measurement at the time which was the "roentgen" AND the Congress also established the International X-Ray and International Commission on Radiological Protection (ICRP) during what?
The Second International Congress on Radiological Protection (ICRP)
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What are the short-tern somatic effects of radiation exposure? What is it also known as?
- AKA-early of acute
- Appear within minutes, hours, days, or weeks after exposure.
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Short-term somatic effects were thought to be preventable if doses were____________________.
Kept below tolerance levels at which no adverse biological effects were demonstrated. (if kept below this threshold dose, there would be no adverse effects from exposure demonstrated)
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In 1934, what was the tolerance dose per day?
0.2 Roentgen
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In 1936, what was the tolerence dose per day?
0.1 Roentgen
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As scientist realized the ______________, they began to search for a reliable unit to replace the roentgen.
long term (or late) somatic effects and heritable effects
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Who developed the International System of Units(SI units)?
- the U.S. Advisory Committe on X-Ray and Radium Protection
- National Council on Radiation Protection and Measurements (NCRP)
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What did SI units allow?
Allowed various branches of science around the world to interchange information
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When was the tolerance dose replaced? What was it replaced by?
- early 1950's
- the Maximum Permissible Dose (MPD)
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As long as the dose stayed below the _________, there shold not be any significant injury to the body or reproductive cells.
MPD
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The rem was the unit of measurement for what?
MPD
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When did the tolerance level become extinct?
When it was determined that no amount of radiation was safe.
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What was the new approach to determine safe levels after the tolerance level became extenct?
They used the insurance companies approach to work being hazardous or nonhazardous.
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In the new approach after the tolence level became extinct, the new dose limits became based on what?
Probability of harm-based on film badge readings or other dosimeters.
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When were dosimeters able do differentiate between various radiation types? (alpha, beta, gamma, x-ray, neutrons, etc.)
1970's
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In the 1970's there was a base knowledge about what?
The effects of different types of radiation on different tissue types. Some tissues are more sensative than others, while some energies can be more damaging than others.(ex. same dose to skin and bone marrow could have a different efffect. Gamma can cause more damage than alpha to body tissues.
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What year and whom used the epidemiologic damage to atomic bomb survivors to develop the effective dose (EfD)?
- 1991
- ICRP (International Commission on Radiological Protection)
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What is the effective dose based on?
The energy deposited in biologic tissue by ionizing radiation.
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What does EfD take into account?
The type of radiation and the sensitivity of tissues. (this quanity is actually a measure of the overall risk arising from the irradiation of biologic tissue and organs)(it takes into consideration the exposure to the entire body)
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What is the SI unit for the EfD?
Sievert (Sv). (rem is the traditional unit)
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The ICRU encourages the implementatin of the _________in all developed countries.
SI units (The U.S. has been slow at adopting the SI unit system)
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What two units of measurement are widely employed?
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What is the internationally accepted unit for measurement of exposure to x-radiation and gamma radiation?
Roentgen
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One roentgen is the photon exposure that under standard conditions of pressure and temperature produces a total positive or negative ion charge of___________.
2.58 x (10)-4 coulombs per kilogram of dry air
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What is the short definition of the roentgen?
Ionization in air!
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Survey meters and calibration chambers use the unit of___ to measure the______________.
- R
- intensity of radiation in air!
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What is a traditional unit?
Special units associated with radiation protection and dosimetry (roentgen and rem)
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What kind of unit of measurement is rem?
traditional
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Rem is what kind of dose?
equivalent dose
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What is rem?
The dose that is equivalent to any type of ionizing radiation that produces the same biologic effect as 1 rad of x-radiation. 1 rad corresponds to an energy transfer of 100 ergs per gram of irradiated object.
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What is used on Landauer Reports to measure your clinical exposure?
Rem
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What is the SI unit for absorbed dose?
Gray (Gy)
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What is the traditional unit for absorbed dose?
rad (radiation absorbed dose)
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What theory relates the energy absorbed in a medium to the energy of radiation it was exposed. It takes into consideration Z#'s and density of mediums ability to absorb energy. Also, energy of the photon and its ability to be absorbed or penetrate the medium. (ISODOSE CURVES)
Bragg-Gray Theory(1936)
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What is the abriviation for exposure?
X
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What is the abreviation for absorbed dose?
D
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What is the abreviation for equivalent dose?
EqD
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What is the abreviation for effective dose?
EfD
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The amount of radiation responsible for the ionization of a well-defined volume of air may be determined by measuring the number of electron-ion pairs or charged particles in that volumme of air.
X
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Radiation ionization in air is simpler terms for what?
Exposure
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In the measurement of exposure, positive and negative plates collect oppositely charged ions produced by radiation ionization and give a measurement of___________________.
coulombs per kilogram OR roentgen(the equivalent traditional unit)
-
Defined as the total electrical charge of one sign, either all plusses or all minuses, per unit mass that x-ray and gamma ray photons with energies up to 3 MeV generate in dry air at standard temperature and pressure.
Exposure
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How do you find the precise measurement of radiation exposure? How is it accomplished?
- The total amount of ionization(charge) an x-ray beam produces in a known mass of air must be obtained.
- Accomplished in an accredited calibration lab using a standard or free-air ionization chamber. The chamber contains a known quantity of air with precisely measured temperature, pressure, and humidity. If in that specified volume of dry air the total charge of all the ions of one sign (either all pluses or all minuses) produced is collected and measured, the total amount of radiation exposure may be accurately determined.
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What is the basic unit of electrical charge?
coulomb (C)
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In the SI unit, the exposure unit is measured in?
coulombs per kilogram (C/kg)
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The amount of energy per unit mass absorbed by the irradiated object.
Absorbed dose (D)
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Responsible for damage to tissue exposed to radiation.
D
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What increases absorption?
- lowering radiation energy
- increasing atomic number or density of tissue
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What is the SI unit for absorption?
Gray (1Gy=1J/kg)
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Unit of energy, defined as the work done or energy expended when a force of 1 newton acts on an object along a distance 1 meter.
Joule
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What is the traditonal unit of measurement of absorbed dose?
rad (radiation absorbed dose)
-
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1 rad=______Gy
1 rad=1/100 j/kg=1/100 Gy (ex. 180 rads=1.8cGy or 18mGy)
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Equal absorbed dose of different types of radiation produce different amounts of biologic damage in body tissue. What factor takes this into account?
quality factor (Q)
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Linear energy transfer explains the need for what?
quality factor (Q)
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The amount of energy transfered on average by incident radiation to an object per unit length of tract through an object.
linear energy transfer
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____-LET transfers large amounts of energy into a small area and can do more damage than _____LET.
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____-LET has a greater Q than ____-LET
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EqD=
D x Wr (dose x radiation weighting factor)
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Wr=
radiation weighting factor
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The probability of biologic damage is dependent on the_______.
dose, type and energy of radiation
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The dose, type and energy of radiation is taken into account with what?
Wr (radiation weighting factor)
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What is the Wr of x-ray and gamma ray photons?
1
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What is the Wr of protons?
2
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What is the Wr of neutrons, energy less than 10 kev?
5
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What is the Wr of 10 KeV to 100 KeV,?
10
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What is the Wr greater than 20 MeV?
5
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What is the Wr greater than 2 MeV to 20 MeV?
10
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What is the Wr of greater than 100 KeV to 2 MeV?
20
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What is the Wr of alpha particles?
20
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Provides a measure of the overall risk of exposure to ionizing radiation.
Effective dose
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The ____ the atomic number of material, the greater the amount of absorbed dose.
higher
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When calculating absorbed dose, the number of gray=
rad/100
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When calculating absorbed dose, the number of rad=
Gy x 100
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