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