Chapter 4: Radiation Quantities and Units Flashcards

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1
Q

who discovered xrays

A

wilhelm conrad roentgen

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2
Q

when was xrays discovered

A

November 8, 1895

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3
Q

how was xrays discovered

A

with crookes tube

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4
Q

First xray image

A

roentgens wifes hand

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5
Q

who was the first fatality

A

Clarence Dally

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6
Q

what was the crookes tube then updated to

A

Coolidge tube

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7
Q

who discontinued his xray research because of clarence dallys injuries and death

A

Thomas edison

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8
Q

when did clarence dally die

A

October 1904

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9
Q

Result of excessive occupational radiation exposure for early pioneers and excessive exposure of patients
Radiodermatitis
Cancer
Blood disorders

A

Radiodermatitis
Cancer
Blood disorders

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10
Q

somatic

A

to yourself

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11
Q

genetic

A

future generations

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12
Q

when were committees being started

A

1910
first death was 1904

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13
Q

best overall dose

A

effective dose

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14
Q

Early tissue reactions

A

nausea
fatigue
diffuse redness of the skin
loss of hair
intestinal disorders
fever
blood disorders
shedding of the outer layer of skin

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15
Q

Late Tissue Reactions

A

Cataract formation
Fibrosis
Organ Atrophy
Loss of parenchymal cells
Reduced Fertility
Sterility

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16
Q

Stochastic Effects

A

Cancer
Genetic (hereditary) effects

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17
Q

stochastic

A

random

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18
Q

meaning nothing is safe

A

nonthreshold

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19
Q

meaning up to a certain point, your fine after that you start seeing reactions

A

Threshold

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20
Q

Unit used from 1900 to 1930 to measure radiation exposure Problems encountered in using the skin erythema dose as a way to measure radiation exposureNeed to find a more reliable unitNew 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

A

Skin Erythema Dose

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21
Q

Concept of tolerance dose

A

Threshold dose

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22
Q

is recommended as a tolerance daily dose limit in 1934

A

0.2 R

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23
Q

is recommended as a tolerance daily dose limit in 1936

A

0.1 R

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24
Q

is a radiation dose to which occupationally exposed persons could be subjected without any apparent harmful acute effects, such as erythema of the skin.

A

Tolerance dose

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25
Q

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.

A

occupational exposure

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26
Q

From 1900 to 1930, the unit in use for measuring radiation exposure was called

A

skin erythema dose

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27
Q

defined as the received quantity of radiation that causes diffuse redness over an area of skin after irradiation.

A

skin erythema dose

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28
Q

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.

A

early tissue reaction

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29
Q

that is, a dose of radiation lower than which an individual has a negligible chance of sustaining specific biologic damage.

A

threshold dose

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30
Q

A radiation dosimetry quantity that was defined by the NRC to monitor and control human exposure to ionizing radiation

A

Total Effective Dose Equivalent (TEDE)

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31
Q

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.

A

36Total Effective Dose Equivalent (TEDE)

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32
Q

If 200 people receive an average effective dose of 0.25 Sv, the collective effective dose is

A

(200)(0.25)= 50 person - sieverts

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33
Q

Used in radiation protection to describe internal and external dose measurement

A

collective EfD

34
Q

Quantity used to describe radiation exposure of a population or group from low doses of different sources of ionizing radiation

A

collective EfD

35
Q

Determined as the product of the average EfD for an individual belonging to the exposed population or group and the number of persons exposed

A

Collective EfD

36
Q

Person-sievert is the radiation unit for this quantity.

A

Collective EfD

37
Q

Units for exposure

A

Coulombs per kilogram

38
Q

units for air kerma

A

Gray

39
Q

Units for absorbed dose

A

Gray

40
Q

Units for equivalent dose and effective dose

A

Sievert

41
Q

In the early 1950s, what replaces tolerance dose

A

Early 1950s: maximum permissible dose (MPD) replaces tolerance dose for radiation protection purposes

42
Q

is the total electric charge of one sign, either all plus or all minus, per unit mass that x-ray and gamma ray photons with energies up to 3 million electron volts (MeV) generated in dry (i.e., nonhumid) air at standard temperature (22° C) and pressure (760 mm Hg or 1 atmosphere at sea level).

A

exposure

43
Q
A
44
Q

It is a radiation quantity “that expresses the concentration of radiation delivered to a specific area, such as the surface of the human body.

A

exposure

45
Q

The basic unit of electric chargeIt is equal to the “amount” of electrical charge moving past a point in a conductor in 1 second when an electric current amounting to 1 ampere is used

A

Coulomb

46
Q

The SI unit of electric current

A

Ampere

47
Q

SI unit of measure for the radiation quantity, exposure, is equal to an electric charge of 1 C produced in a kilogram of dry air by ionizing radiation.

A

Coulomb per kg

48
Q

Acronym forKinetic energy released in airKinetic energy released in materialKinetic energy released per unit mass

A

Air Kerma

49
Q

Gradually replacing the traditional quantity, exposure
Denotes a calculation of radiation intensity in air
Quantity that can be used to express x-ray tube output and inputs to image receptors

A

Air Kerma

50
Q

SI quantity used to express how energy is transferred from a beam of radiation to a material such as the patient’s skin

A

Air Kerma

51
Q

Total amount of ionization (charge) an x-ray beam produces in a known mass of air must be obtained.
This type of direct measurement is accomplished in an accredited dosimetry calibration laboratory by using a standard, or free-air, ionization chamber.
Away from the laboratory much smaller and less complicated instruments are used.
Units used away from the laboratory must be periodically recalibrated in a standardization laboratory against a free-air chamber.

A

19Precise Measurement of Radiation Exposure in Radiography

52
Q

Expressed in metric units of joule per kilogram (J/kg)
May be stated in Gy
When the Gy is used to indicate kinetic radiation energy deposited or absorbed in a mass of air, it is written as Gya.
When the Gy is used to indicate kinetic radiation energy deposited or absorbed in a mass of tissue, it is written as Gyt.

A

air kerma

53
Q

Is the sum total of air kerma over the exposed area of the patient’s surface, or a measure of the amount of radiant energy that has been thrust into a portion of the patients body surfaceIs usually specified in units of mGy-cm2

A

Dose area product

54
Q

A collected electrical charge of 2.58 × 10–4 C/kg of irradiated air constitutes an exposure of 1 roentgen (R

A
55
Q

This quantity is the amount of energy per unit mass absorbed by an irradiated object

A

Absorbed Dose

56
Q

It is responsible for any biologic damage resulting from exposure of the tissues to radiation.
Some structures in the body can absorb more radiant energy than others

A

Absorbed Dose

57
Q

The amount of energy absorbed by a structure depends on the

A

Atomic number (Z) of the tissue comprising the structure
Mass density of the tissue
Energy of the incident photon

58
Q

The Si unit of absorbed dose is :

A

Gy

59
Q

Units for the following :
- in the air
- hit tissue
- scatter

A
  • in the air - coulombs
  • hit tissue - mGy
  • scatter - sieverts
60
Q

-field of view
- how much tissue are you radiating

A

Dose area product

61
Q

Quality Factor of xray

A

1

62
Q

quality factor of beta

A

1

63
Q

quality factor of gamma

A

1

64
Q

quality factor of alpha

A

20

65
Q

Is the product of the average absorbed dose in a tissue or organ in the human body and its associated WR chosen for the type and energy of the radiation in question.

A

EqD

66
Q

Used for radiation protection purposes when a person received exposure from various types of ionizing radiation
For measuring biologic effects may be determined and expressed in Sv or in a subunit of the Sv

A

EqD

67
Q

D x WR and Sv = Gy x WR

A

EqD

68
Q

tissue is only used with which dose

A

effective

69
Q

Must be used when determining EqD Is a dimensionless factor (a multiplier) used for radiation protection purposes to account for differences in biologic impact among various types of ionizing radiationPlaces risks associated with biologic effects on a common scale

A

Radiation Weighting Factor (WR)

70
Q

Provides a measure of the overall risk of exposure to humans from ionizing radiation

A

EfD

71
Q

“The sum of the weighted equivalent doses for all irradiated tissues or organs” (NCRP Report No. 116)Incorporates both the effect of the type of radiation used and the variability in radiosensitivity of the organ or body part irradiated through the use of appropriate weighting factorsThese factors quantify the overall potential harm to those biologic components and the risk of developing a radiation-induced cancer or, for the reproductive organs, the risk of genetic damage.

A

EfD

72
Q

D × WR × WT

A

EfD

73
Q

Takes into account the relative detriment to each specific organ and tissueUsed in the calculation of EfDA value that denotes the percentage of the summed stochastic (cancer plus genetic) risk stemming from irradiation of tissue (T) to the all-inclusive risk, when the entire body is irradiated in a uniform fashionAccounts for the risk to the entire organism brought on by irradiation of individual tissues and organs

A

Tissue Weighting Factor (WT)

74
Q

Used in radiation protection to describe internal and external dose measurements

A

Collective EfD

75
Q

Person-sievert is the radiation unit for this quantity

A

Collective EfD

76
Q

Quantity used to describe radiation exposure of a population or group from low doses of different sources of ionizing radiation

A

Collective EfD

77
Q

Determined as the product of the average EfD for an individual belonging to the exposed population or group and the number of persons exposed

A

Collective EfD

78
Q

is another SI quantity that is used to express how energy is transferred from a beam of radiation to air. It is mostly replacing the traditional quantity, exposure.

A

Air Kerma

79
Q

is defined as the amount of energy per unit mass absorbed by an irradiated object

A

Absorbed Dose

80
Q
A