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Flashcards in chapter 4 EXAM 2 Deck (87):
1

somatic damage

biologic damage to the body of the exposed individual

2

who was the first recognized american xray fatality

clarence daily
died oct. 1904

3

occupational exposure

radiation exposure received by radiation workers in the course of exercising their professional responsibilities

4

what diseases are more common among radiologist than non radiologists

aplastic anemia and leukemia

5

british xray and radium protection committee

formed in 1921 to investigate methods for reducing radiation exposure
unfortunately they could not agree on things and did not fulfill their responsibility

6

skin erythema dose

the first unit for measuring radiation exposure (1900-1930)

7

skin erythema dose definition

received quantity of radiation that causes diffused redness over an area of skin after irradiation

8

first international congress of radiology

in london england in 1925
allowed collaboration of rads from around the world
no decisions for measuring ionizing radiation

9

the international commission on radiation units and measurements ICRU

formed in 1925
finished the job from the second international congress of radiology
roentgen became the internationally accepted unit of measurement for x radiation and gamma radiation

10

second international congress of radiology

stockholm sweeden 1928
made the roentgen accepted as a unit of exposure but could not define it so the ICRU did in 1937

11

short term somatic effects (early or acute effects)
definition

somatic effects that appear within minutes hours days or weeks of the time of radiation exposure

12

list of short term somatic effects (early or acute effects)

nausea
fatigue
redness of skin
loss of hair
fever
blood disorders
shedding of skin

13

tolerance dose

a radiation dose to which occupationally exposed persons could be continuously subjected without any apparent harmful acute effects
believed nothing would happen as long as it was kept below dose

14

in 1934 internation xray and radium protection committee recommended a tolerance dose of

0.2 roentgen a day
was reduced to 0.1 roentgen a day in 1936

15

threshold dose

a dose of radiation below which an individual has a negligible chance of sustaining specific biologic damage

16

long term or late somatic effects definition

effects of ionizing radiation that appeared months or years following exposure to ionizing radiation

17

long term or late somatic effects list

cancer
embryonic effects (birth defects)
formation of cataracts

18

the general conference of weights and measurements created

the international system of units to be able to interchange units throughout the world

19

when was tolerance dose replaced and what was it replaced by

early 1950s and it was replaced by the maximum permissible dose MPD

20

maximum permissible dose MPD

a term used in the past to indicate the maximum dose equivalent of ionizing radiation that an occupationally exposed person could absorb in a specified time without sustaining bodily injury

21

MPD meant that

no amount of radiation was considered completely safe

22

1 sievert is equal to how many rem

100 rem

23

what are the 5 radiation quantities

1. exposure
2. air kerma
3. absorbed dose
4. equivalent dose
5. effective dose

24

exposure is measured in

reontgen (traditional)
columb per kilogram (SI)

25

air kerma is measured in

gray with subscripts "a" or "t"

26

absorbed dose is measured in

Rad (traditional)
gray (SI)

27

equivalent does is measured in

Rem (traditional)
sievert (SI)

28

effective dose is measured in

Rem (traditional)
sievert (SI)

29

exposure (x)

the total electrical charge of one sign, either all pluses or minuses, per unit mass
basically measures the amount of ion pairs in the air.

30

exposure is measured by an

ionization chamber

31

coulomb (C)

a basic unit of electrical charge

32

how do you convert from roentgens to coulombs per kilogram

multiply the number of roentgens by 2.58 x 10^-4

33

how do you convert coulombs per kilogram to roentgens

divide the coulombs per kilogram by 2.58x10^-4

34

air kerma

SI quantity that can be used to express radiation concentration transferred to a point
kinetic energy released in a unit mass of air
basically indicates a calculation of radiation intensity in air

35

air kerma is replacing what

the traditional quantity, exposure

36

Kerma is an acronym for

kinetic energy released in matter
kinetic energy released per unit mass

37

air kerma is expressed in metric units of

joule per kilogram

38

joule is the metric unit of

energy

39

tissue kerma

energy released in a unit mass of tissue

40

tissue kerma is measured in

Gray

41

air kerma is expressed as

Gya

42

tissue kerma is expressed as

Gyt

43

if the air kerma is measured at a point where soft tissue is located,

the absorbed dose in the tissue will be about the equal to the air kerma

44

dose area product

the sum total or air kerma over the exposed area of the patients surface

45

DAP is expressed in units of

mGy/cm^2

46

DAP is the most practical quantity for

monitoring the radiation delivered to patients

47

absorbed dose (D)

the amount of energy per unit mass absorbed by the irradiated object

48

absorbed dose is used to indicate

the amount of ionizing radiation a patient receives during a procedure

49

amount of energy absorbed by a patient depends on

atomic number (Z)
mass density
energy of incoming photon

50

absorption increases as

atomic number and mass density increases and photon energy decreases

51

effective atomic number (Zeff)

weighted average of atomic numbers

52

T or F
bone has a higher effective atomic number than soft tissue

true

53

Zeff of bone =

13.8

54

Zeff of soft tissue =

7.4

55

what is the only measure of ionization in air and not other tissues

exposure

56

1 gray = how many joules/kilogram

1 joule/kilogram

57

what is the traditional unit for joule

erg

58

1 gray = how many rads

100 rad

59

how do you convert rad to gray

divide the rad by 100 to get gray

60

how to convert gray to rad

multiply the gray by 100

61

how to convert from gray to milligray

multiply by 1000

62

how to convert from milligray to gray

divide by 1000

63

in therapeutic radiology what is replacing the rad for recording absorbed dose

the centigray

64

to convert gray to centigray

multiply by 100

65

surface integral dose SID

the total amount of radiant energy transferred by ionizing radiation to the body during an exposure

66

quality factor AKA radiation weighting factor

an adjustment multiplier used in the calculation of dose equivalent

67

linear energy transfer LET

the amount of energy deposited on average by ionizing radiation in an object per unit length of track as it passes through the object

68

Linear energy transfer is measured in

KeV/micrometer

69

high LET

departs energy quickly and causes more biologic damage
alpha particles have a high LET

70

low LET

more sparsely ionizing.
less chance of producing biologic damage because it disperses its energy

71

LET helps explain

the quality factor or modifying factors for different types of ionizing radiation

72

equivalent dose enables the calculation of

effective dose

73

stochastic effects

non threshold, randomly occurring biologic effects of ionizing radiation

74

the probability of stochastic effects depends on

radiation dose and type of energy of the ionizing radiation

75

the higher the radiation weighting factor of a type of ionizing radiation, the more

effective it is at producing biologic damage

76

equivalent dose is obtained by multiplying

the absorbed dose (D) by the radiation weighting factor (Wr)
or Sv = Gy x Wr

77

how to convert the sievert to the microsievert

multiply the sievert by 1,000,000

78

effective dose

the sum of the weighted equivalent doses for all irradiated tissues and organs

79

effective dose includes

the type of radiation and the radiosensitivity of the specific organ or body part

80

tissue weighting factor

a value that denotes the percentage of the stochastic risk stemming from the irradiation of tissue

81

how to determine effective dose

an absorbed dose (D) is multiplied by a radiation weighting factor to obtain the equivalent dose. then the equivalent dose is multiplied by a tissue weighting factor to obtain the effective dose.

82

collective effective dose ColEfD

the product of the average effective dose for an individual belonging to the exposed population or group and the number of persons exposed

83

what is the unit for ColEfD

person-sievert

84

what does the total effective dose equivalent do TEDE

to monitor and control human exposure to ionizing radiation

85

what is the TEDE

the sum of effective dose equivalent from external radiation sources and a quantity called committed effective dose equivalent (CEDE) from internal exposures

86

TEDE is a useful dose monitor for

occupationally exposed personnel

87

for occupationally exposed personnel, the whole body TEDE regulatory limit is

0.05 sieverts or 50 milisieverts