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Radiation Protection > Week 4 > Flashcards

Week 4 Flashcards

1
Q

What were some of the early radiation-induced injuries and fatalities encountered by experimenters?

A

Early injuries included radiodermatitis, skin cancer, aplastic anemia, and leukemia, affecting both experimenters and patients.

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2
Q

Describe the first known American radiation fatality and the circumstances around it.

A

Clarence Dally, Thomas Edisons assistant, died in 1904 from radiation-induced cancer after years of X-ray experimentation.

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3
Q

What role did the Crookes tube play in the discovery of X-rays?

A

The Crookes tube was used by Roentgen in his experiments that led to the discovery of X-rays.

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4
Q

How is radiation exposure precisely measured in radiography using a standard ionization chamber?

A

Exposure is measured using a free-air ionization chamber that quantifies ionizations in a known air volume.

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5
Q

What is the relationship between Linear Energy Transfer (LET) and biologic damage?

A

Higher LET radiation causes more dense ionization, leading to increased biologic damage compared to lower LET radiation.

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6
Q

What was the role of the International Commission of Radiation Units and Measurements (ICRU)?

A

The ICRU was formed to define radiation quantities and units, including the roentgen (R) as a unit of exposure.

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7
Q

Discuss the significance of the adoption of SI units for ionizing radiation by the ICRU and NCRP.

A

The adoption of SI units standardized radiation measurements globally, improving accuracy and consistency in radiation protection.

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8
Q

Describe the quantity exposure in terms of how it is measured and its units.

A

Exposure measures the ionization produced in air by X-ray/gamma radiation, recorded in C/kg or roentgen (R).

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9
Q

What was the skin erythema dose and why was it considered problematic as a unit of measurement?

A

The skin erythema dose was used to measure radiation exposure based on skin reddening, but it was unreliable for measuring radiation accurately.

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10
Q

Explain the significance of Coulombs per kilogram (C/kg) in measuring radiation exposure.

A

C/kg is the SI unit for exposure, indicating electrical charge produced by ionizing radiation per mass of air.

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11
Q

Describe how the absorbed dose is converted to dose equivalent for different types of radiation.

A

Dose equivalent is calculated by multiplying the absorbed dose by the Quality Factor specific to the type of radiation.

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12
Q

When and where was the first International Congress of Radiology held?

A

The first International Congress of Radiology was held in London, England, in 1925.

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13
Q

What is a free-air ionization chamber, and how does it function?

A

Its a device with air volume and charged plates that measures ionization to determine X-ray exposure.

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14
Q

What is the significance of the unit tolerance dose in radiation protection history?

A

Tolerance dose was an early method to limit occupational radiation exposure by setting a threshold dose considered safe.

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15
Q

How did the perception of radiation effects change the need for updated measurement units?

A

Recognition of late deterministic and stochastic effects necessitated updated units to better assess and limit exposure and risks.

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16
Q

Who discovered X-rays and where was this discovery made?

A

X-rays were discovered by Wilhelm Conrad Roentgen at the University of Wurzburg in Bavaria.

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17
Q

What led to the establishment of the International X-Ray and Radium Protection Committee?

A

Need for global coordination in radiation standards led to the committees creation as a precursor to ICRP.

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18
Q

When was the roentgen (R) accepted as a unit of exposure, and what organization was responsible for this decision?

A

The roentgen (R) was accepted as a unit of exposure in 1928 by the Second International Congress of Radiology.

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19
Q

Explain the difference between absorbed dose, equivalent dose, and effective dose.

A

Absorbed dose measures energy deposited, equivalent dose accounts for radiation type, and effective dose considers tissue sensitivity.

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20
Q

What is the historical significance of November 8, 1895, in the context of radiation measurement?

A

November 8, 1895, marks the discovery of X-rays by Wilhelm Conrad Roentgen.

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21
Q

What prompted the replacement of the tolerance dose with the maximum permissible dose (MPD) in the early 1950s?

A

Increasing awareness of the risks of radiation prompted the shift to MPD to better protect against both deterministic and stochastic effects.

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22
Q

Define the traditional units of exposure, absorbed dose, and dose equivalent.

A

Traditional units include roentgen (R) for exposure, rad for absorbed dose, and rem for dose equivalent.

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23
Q

What is the Quality Factor (QF) and how does it differ for x-ray/gamma, beta, and alpha radiation?

A

QF accounts for radiation type differences in biological effect: 1 for x-ray/gamma, 1 for beta, and 20 for alpha radiation.

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24
Q

How has the understanding of somatic and genetic effects of radiation evolved over time?

A

Over time, awareness of deterministic and stochastic effects, including potential genetic impact, prompted stricter standards.

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25
Q

What are the comprehensive modern units and quantities for measuring ionizing radiation?

A

Modern units include coulombs per kilogram (C/kg) for exposure, gray (Gy) for absorbed dose, and sievert (Sv) for dose equivalent.

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26
Q

What is the process for converting R to C/kg and where can this information be found?

A

Conversion from R to C/kg can be accomplished by referring to Appendix A in the textbook.

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27
Q

How is Collective EfD measured using the person-sievert unit?

A

Collective EfD is determined by multiplying the average effective dose for a population by the number of exposed individuals, using person-sievert as the unit.

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28
Q

In what units is Air Kerma expressed, and what are the conversions to Gy?

A

Air Kerma is expressed in joules per kilogram (J/kg) and can be stated in Gray (Gy). When in air, it is written as Gy a and in tissue as Gy t.

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29
Q

What role does Tissue Weighting Factor (WT) play in determining EfD?

A

WT accounts for relative risk of each organ and tissue in EfD calculation, indicating risk of cancer or genetic damage.

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30
Q

Explain why subunits such as cGy are used and their relationship to rad.

A

Subunits like cGy are used due to small radiation doses in exams; 1 cGy is numerically identical to 1 rad.

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31
Q

What is Collective Effective Dose (Collective EfD) and how is it used?

A

Collective EfD describes radiation exposure for populations, calculated as average EfD multiplied by the number of exposed individuals, measured in person-sievert.

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32
Q

Why is the millisievert (mSv) often used for specifying radiation doses in diagnostic radiology?

A

mSv is used to specify doses because diagnostic radiology doses for workers are relatively small.

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33
Q

Explain the significance of the acronym for Air Kerma.

A

Air Kerma stands for Kinetic energy released in matter, material, or per unit mass.

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34
Q

How does the atomic number and mass density of tissue affect the absorbed dose?

A

The absorbed dose depends on the tissues atomic number, mass density, and the energy of incident photons.

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35
Q

What considerations does TEDE address for occupationally exposed personnel?

A

TEDE is a vital monitor for occupationally exposed personnel like technologists, capturing significant yearly radiation exposures.

36
Q

How is Equivalent Dose (EqD) expressed using Gy and Sv?

A

EqD is expressed in Sieverts (Sv) and calculated as EqD = D (in Gy) x WR.

37
Q

How does the concept of dose equivalence account for biologic impact?

A

Dose equivalence uses a quality factor to adjust absorbed dose values, considering different biologic impacts from various ionizing radiation types.

38
Q

Define absorbed dose and its importance in understanding biological damage.

A

Absorbed dose is the energy absorbed per unit mass by an object and is crucial for assessing biological damage from tissue exposure to radiation.

39
Q

What is the SI unit for absorbed dose and how is it defined?

A

The SI unit for absorbed dose is the Gray (Gy), defined as one Joule of energy absorbed per kilogram of tissue.

40
Q

Summarize the history of radiation measurement.

A

Radiation measurement evolved to protect from exposure, now using standardized units like Gy and Sv for accurate dose assessment.

41
Q

How does TEDE account for external and internal radiation exposure?

A

TEDE includes both external effective dose equivalent and committed effective dose equivalent from internal exposures.

42
Q

Define Linear Energy Transfer (LET) and its impact on biologic damage.

A

LET is energy transferred per unit length by radiation through matter, affecting biologic damage—higher LET causes more damage.

43
Q

What is Dose Area Product (DAP) and how is it measured?

A

DAP is the total of air kerma over the exposed area of a patients surface, measured in units of mGy-cm².

44
Q

What is Air Kerma and how does it differ from the traditional quantity of exposure?

A

Air Kerma is the SI quantity used to express how energy is transferred from radiation to a material, replacing the traditional quantity of exposure by measuring radiation intensity in air.

45
Q

How is C/kg used in the calibration of X-ray equipment and radiation survey instruments?

A

C/kg is used for X-ray equipment calibration and for calibrating radiation survey instruments.

46
Q

Describe Effective Dose (EfD) and its importance in measuring radiation risk.

A

EfD quantifies overall risk from radiation exposure, considering type of radiation and organ sensitivity, calculated as EfD = D x WR x WT.

47
Q

What is Total Effective Dose Equivalent (TEDE) and its purpose in radiation dosimetry?

A

TEDE measures total human ionizing radiation exposure, summing external and committed effective dose equivalents, vital for occupational exposure monitoring.

48
Q

Define Surface Integral Dose (SID) and the units used to express it.

A

SID is the total radiant energy transferred to the body during exposure, measured in Gy-m².

49
Q

What is the Radiation Weighting Factor (WR) and its purpose?

A

WR is a dimensionless factor for radiation protection, accounting for different biologic impacts among ionizing radiation types.

50
Q

Explain how Equivalent Dose (EqD) is calculated and its units.

A

EqD is the product of absorbed dose and the WR, expressed in Sieverts (Sv). EqD = D x WR.

51
Q

What distinguishes absorbed dose from equivalent dose?

A

Absorbed dose measures energy per unit mass, while equivalent dose accounts for biological effects.

52
Q

How did the definition of the roentgen (R) change by 1937?

A

It was internationally accepted as the unit of measurement for x-radiation exposure.

53
Q

What does air kerma signify in radiation measurement?

A

It expresses how energy is transferred from radiation to matter, such as skin.

54
Q

How does air kerma replace traditional exposure units in modern practices?

A

Air kerma quantifies radiation intensity in air, enhancing accuracy over traditional exposure.

55
Q

What is the significance of the radiation weighting factor (Wr) in radiation measurement?

A

It adjusts absorbed dose values to account for biological impact variations.

56
Q

What unit of exposure was accepted at the Second International Congress of Radiology in 1928?

A

The roentgen (R) was accepted as a unit of exposure.

57
Q

Who discovered x-rays and how was the discovery made?

A

Wilhelm Conrad Roentgen discovered x-rays using a Crookes tube.

58
Q

What types of somatic injuries were reported by early pioneers of radiation?

A

Radiodermatitis, cancer, and blood disorders.

59
Q

What milestone occurred at the First International Congress of Radiology in 1925?

A

The International Commission of Radiation Units and Measurements (ICRU) was formed.

60
Q

What role does the International Commission on Radiation Protection (ICRP) play in the establishment of radiation safety standards?

A

The ICRP develops guidelines and recommendations for radiation protection worldwide.

61
Q

How is the effective dose (EfD) calculated?

A

EfD = D × WR × WT, incorporating both type of radiation and tissue radiosensitivity.

62
Q

How are SI units applied in measuring radiation today?

A

SI units like gray (Gy) and sievert (Sv) are standard for measuring radiation doses.

63
Q

What is the relationship between effective dose and the risk of developing radiation-induced conditions?

A

EfD quantifies overall risk of cancer and genetic damage from radiation exposure.

64
Q

How is the term person-sievert used in radiation exposure assessments?

A

It quantifies radiation exposure to individuals within a population.

65
Q

Why is it important for medical professionals to understand radiation quantities and units?

A

It helps ensure patient safety and compliance with radiation protection standards.

66
Q

What is the purpose of collective effective dose (EfD) in radiation protection?

A

It measures the radiation exposure of a population from low doses of ionizing radiation.

67
Q

What is the SI unit for absorbed dose and how is it defined?

A

Gray (Gy), defined as one joule of energy per kilogram of tissue.

68
Q

What is the historical significance of November 8, 1895, in radiation measurement?

A

It marks the discovery of x-rays by Wilhelm Conrad Roentgen.

69
Q

What impact do different types of radiation have on biological damage despite equivalent absorbed doses?

A

Different radiation types produce varying biological effects, even with similar absorbed doses.

70
Q

What is the concept of equivalent dose (EqD) in radiation protection?

A

It is the product of the average absorbed dose and the radiation weighting factor.

71
Q

What was the role of the Crookes tube in the discovery of x-rays?

A

It was used to generate x-rays during Roentgens experiments.

72
Q

What does the term Total Effective Dose Equivalent (TEDE) encompass?

A

It is the sum of effective dose equivalent from external and internal radiation exposures.

73
Q

Why was barium platinocyanide important in early x-ray experiments?

A

It fluoresced when exposed to x-rays, helping to visualize their presence.

74
Q

How is the absorbed dose (D) defined and measured?

A

It is the amount of energy per unit mass absorbed by an irradiated object.

75
Q

What are the traditional non-metric units associated with radiation quantities?

A

Roentgen (R), rad, and rem.

76
Q

Who was Clarence Dally and what happened to him related to radiation exposure?

A

Clarence Dally was Thomas Edisons assistant, who died from radiation-induced cancer.

77
Q

What are the subunits commonly used for measuring absorbed dose in radiology?

A

Centigray (cGy) and milligray (mGy).

78
Q

What organization was established to ensure radiation protection in the early 20th century?

A

The U.S. Advisory Committee on X-Ray and Radium Protection.

79
Q

What was the recommended tolerance daily dose limit in 1934?

A

0.2 roentgen (R).

80
Q

What were the limitations of using skin erythema dose as a radiation exposure measurement?

A

It was not a reliable measure of radiation exposure due to individual variations.

81
Q

What does the term skin erythema dose refer to in radiation measurement?

A

It refers to the dose of radiation that causes reddening of the skin.

82
Q

How did the concept of tolerance dose evolve from the 1930s onwards?

A

It was refined to minimize risks associated with radiation exposure.

83
Q

What factors affect the amount of energy absorbed in a structure by radiation?

A

Atomic number, mass density, and energy of the incident photon.

84
Q

How does linear energy transfer (LET) relate to biological damages from radiation?

A

LET describes energy transfer per unit length, impacting the extent of biological damage.

85
Q

What does MPD stand for and how was it implemented in radiation protection?

A

MPD stands for Maximum Permissible Dose, replacing tolerance dose in the 1950s.

Radiation Protection (17 decks)

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