Radiation Quantities and Units Flashcards
1
Q
Discovery of Rays
- Need to develop standards for ___ and ___ radiation exposure
- ___ ___, 1___ Wilhelm Roentgen discovered x-rays.
- Within the following months many pioneers began their experiments using this new beam.
- As early as 1896 reports of ___ ___ to the body caused by exposure to ___ ___ were reported in Europe.
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Discovery of Rays
- Need to develop standards for measuring and limiting radiation exposure
- November 8, 1895 Wilhelm Roentgen discovered x-rays.
- Within the following months many pioneers began their experiments using this new beam.
- As early as 1896 reports of biologic damage to the body caused by exposure to ionizing radiations were reported in Europe.
2
Q
Clarence Madison Dally
- First American died from radiation-induced ___ in October 1904 at the age of 39.
- Other physicians reported ___ ___ ___ and ___ resulted in:
- occupational exposure from early radiation workers which reported:
- ___ – ___ of the skin
- ___ ___ – blood disorders
- ___ – abnormal overproduction of ___ ___ cells
A
Clarence Madison Dally
- First American died from radiation-induced cancer in October 1904 at the age of 39.
- Other physicians reported biological tissue damages and deaths resulted in:
- occupational exposure from early radiation workers which reported:
- Radiodermatitis – reddening of the skin
- Aplastic anemia – blood disorders
- Leukemia – abnormal overproduction of white blood cells
3
Q
Somatic Damage
- Result of excessive ___ radiation exposure for early ___ and excessive exposure of ___
- ___itis
- ___
- ___ disorders
A
Somatic Damage
- Result of excessive occupational radiation exposure for early pioneers and excessive exposure of patients
- Radiodermatitis
- Cancer
- Blood disorders
4
Q
Need to Develop Standards for Measuring and Limiting Radiation Exposure
- 1st standard was the ___ ___ ___
- Developed from 19__ to 19__
- Defined as the received ___ of radiation that causes diffuse ___ over an area of skin after ___
- Not ___ as depended on the ___ and ___ of radiation exposure
- The ___ ____ on ___ ___ and ___ (ICRU) was formed in 1925 to develop new units of measure.
A
Need to Develop Standards for Measuring and Limiting Radiation Exposure
- 1st standard was the Skin Erythema Dose
- Developed from 1900 to 1930
- Defined as the received quantity of radiation that causes diffuse redness over an area of skin after irradiation
- Not reliable as depended on the equipment and type of radiation exposure
- The International Commission on Radiation Units and Measurements (ICRU) was formed in 1925 to develop new units of measure.
5
Q
Early Deterministic Somatic Effects
- Deterministic – you know ___ ___ will occur
- Somatic – the effects will occur on the ___ ___
- Tolerance dose is a radiation dose to which ___ exposed person could be ___ subjected without any apparent ___ ___ effects.
- *today no radiation exposure is considered to be ___ (___ Principle)
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Early Deterministic Somatic Effects
- Deterministic – you know radiation effects will occur
- Somatic – the effects will occur on the exposed individual
- Tolerance dose is a radiation dose to which occupationally exposed person could be continuously subjected without any apparent harmful acute effects.
- *today no radiation exposure is considered to be safe (ALARA Principle)
6
Q
Effects of Radiation
A
Effects of Radiation
7
Q
Roentgen Unit was Developed
- In 1930 – first unit was ___ — Tolerance dose was ___ per day
- In 1936 – Tolerance dose was ___ per day
- In 1948 – The ___ ___ of ___ (___ units) were developed
- In 1950 – ___ ___ dose replaced the tolerance dose for ___ workers
A
Roentgen Unit was Developed
- In 1930 – first unit was Roentgen — Tolerance dose was 0.2 R per day
- In 1936 – Tolerance dose was 0.1R per day
- In 1948 – The international Systems of Units (SI units) were developed
- In 1950 – maximum permissible dose replaced the tolerance dose for occupational workers
8
Q
1970 – Dosimetry and Risk Analysis
- Become quite sophisticated by just the means to measure the amount of ___ and comparing to the ___ ___
- Radiation units were developed for the ___ of different types of radiation:
- ___
- ___
- ___
- ___
- ___
A
1970 – Dosimetry and Risk Analysis
- Become quite sophisticated by just the means to measure the amount of exposure and comparing to the risks factors
- Radiation units were developed for the bioeffects of different types of radiation:
- *- Alpha
- Beta
- Gamma
- X-radiation
- Neutrons**
9
Q
1991 the ICRP Revisions
- Findings based on data from ___ ___ survivors
- Adopted the term: ___ (___) on the ___ deposited in the tissue by ___ radiation which includes:
- Type of radiation
- Variable sensitivity of the ___ exposed to radiation (___ vs. ___ ___ vs. ___)
- Exposure to the ___ body vs ___ area of the body
- EfD is expressed in ___ (___) or ___ (___)
A
1991 the ICRP Revisions
- Findings based on data from atomic bomb survivors
- Adopted the term: Effected dose (EfD) on the energy deposited in the tissue by ionizing radiation which includes:
- Type of radiation
- Variable sensitivity of the tissues exposed to radiation (skin vs. blood cells vs. gonads)
- Exposure to the whole body vs smaller area of the body
- EfD is expressed in sieverts (Sv) or millisieverts (mSv)
10
Q
Units Today
- ___ units have replaced the traditional units in the US on the ARRT beginning in January 2017.
Name changes:
- ___ (___) = ___ - Radiation measured in ___
- ___ = ___ - Radiation ___ to ___
- ___ = ___ - Radiation ___ dose
A
Units Today
- SI units have replaced the traditional units in the US on the ARRT beginning in January 2017.
Name changes:
- Roentgen (R) = Coulomb - Radiation measured in air
- Rem = Sievert - Radiation equivalent to man
- Rad = Gray - Radiation absorbed dose
11
Q
Radiation Quantities and their units of measure
These are the 5 ways to describe the measurements of radiation exposure:
-
- 5.
A
Radiation Quantities and their units of measure
These are the 5 ways to describe the measurements of radiation exposure:
- Exposure (X)
- Air Kerma
- Absorbed dose (D)
- Equivalent dose (EqD)
- Effective dose (EfD)
12
Q
Exposure (X)
Described as the ___ of ___ charge of ___ radiation that may ___ an object when the vicinity of a radiation course.
A
Exposure (X)
Described as the amount of electrical charge of ionizing radiation that may strike an object when the vicinity of a radiation course.
13
Q
Air Kerma
- SI quantity that can be used to express radiation ___ transferred to a ___, which may be at the ___ of a patient’s or radiographer’s ___
- Gradually replacing the traditional quantity, ___
- Denotes a calculation of radiation ___ in ___
- Quantity that can be used to express x-ray tube ___ and ___ to ___ ___
Acronym for:
- Kinetic energy released in ___
- Kinetic energy released in ___
- Kinetic energy released per ___ ___
- Expressed in metric units of ___ per ___ (__/__)
- May be stated in ___
- When the Gy is used to indicate ___ radiation energy deposited or absorbed in a mass of ___, it is written as ___
- When the Gy is used to indicate ___ radiation energy deposited or absorbed in a mass of ___, it is written as ___
A
Air Kerma
- SI quantity that can be used to express radiation concentration transferred to a point, which may be at the surface of a patient’s or radiographer’s body
- 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
Acronym for:
- Kinetic energy released in matter
- Kinetic energy released in material
- Kinetic energy released per unit mass
- 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
14
Q
Dose Area Product (DAP)
- Is the sum total of ___ ___ over the ___ area of the patient’s surface or, a measure of the amount of radiant ___ that has been thrust into a portion of the patients body surface
- Is usually specified in units of ___-cm²
A
Dose Area Product (DAP)
- 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
15
Q
Absorbed Dose
- Is the deposition of ___ per unit ___ in the patient’s body to ___ radiation
- This quantity is the amount of ___ per unit mass absorbed by an ___ object
- It is responsible for any ___ ___ resulting from exposure of the ___ to radiation
- Some structures in the body can ___ more radiant energy than others.
A
Absorbed Dose
- Is the deposition of energy per unit mass in the patient’s body to ionizing radiation
- This quantity is the amount of energy per unit mass absorbed by an irradiated object
- 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.
20
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21
Q
Effective Dose EfD
- Takes into account the ___ of the tissue
- EfD = radiation dose x Wr x Wt
- Organ/Tissue and their Wt
- *is measured in ___ (___ or ___)
A
Effective Dose EfD
- Takes into account the radiosensitivity of the tissue
- EfD = radiation dose x Wr x Wt
- Organ/Tissue and their Wt
- *is measured in Sieverts (Sv or mSv)
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24
Q
Roentgens to Coulombs
- 1 R = 2.58 x 10-4 C/kg
- Know the value but an easier unit to work with is gray
- (Gya) measured in air:
- Gya states for ___ measured in ___ ___
- ___ R = 1 Gya (___ ___ ___)
A
Roentgens to Coulombs
- 1 R = 2.58 x 10-4 C/kg
- Know the value but an easier unit to work with is gray
- (Gya) measured in air:
- Gya states for gray measured in air kerma
- 100 R = 1 Gya (gray in air)
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28
Q
Subunit Conversions
Because many x-ray examinations require small radiation doses, ___ may frequently be used to indicate ___ dose values. These subunits are only a ___ of a specific unit.
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Subunit Conversions
Because many x-ray examinations require small radiation doses, subunits may frequently be used to indicate absorbed dose values. These subunits are only a fraction of a specific unit.
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