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Radiation Limitation Flashcards

(83 cards)

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1
Q

As growth and proliferation rate increase, radio –sensitivity____________(increase/Decrease)

A

Increase

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2
Q

When metabolic activity is high, radio- sensitivity is also low. (True or false)

A

False

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3
Q

Three cardinal principles of radiation protection?

A

Time, distance, and shielding

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4
Q

The product of Exposure rate and Exposure Time will give you the ____________.

A

Occupational exposure

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5
Q

If the distance from the source exceeds five times the source diameter, it can be treated as a _______________

A

Point source

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6
Q

The thickness of the absorber that will reduce the radiation intensity to one-half of its original intensity is known as______________

A

Half value layer (HVL)

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7
Q

The thickness of the absorber that will reduces the radiation intensity to one-tenth of its original intensity is known as ____________

A

Tenth value layer (TVL)

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8
Q

How many half value layers equal a tenth value layer?

A

1 TVL = 3.3HVL

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9
Q

What is the formula to calculate equivalent dose?

A

Equivalent dose= Absorbed dose x Tissue weighting factor

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10
Q

What is the formula to calculate effective dose?

A

Effective dose= Absorbed dose x Radiation weighting factor X Tissue weighting factor

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11
Q

What is the radiation weighting factor for alpha particle?

A

20

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12
Q

What is the radiation weighting factor for gamma rays?

A

1

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13
Q

What is the tissue weighting factor for gonads?

A

0.20

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14
Q

What is the tissue weighting factor for thyroid?

A

0.05

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15
Q

What is the tissue weighting factor for bone marrow?

A

0.12

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16
Q

Occupational effective dose is ________% of the monitor dose.

A

10

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17
Q

Leakage radiation must be less than _____mR/Hour at a distance of 1 meter from the protective housing.

A

100

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18
Q

Leakage radiation must be less than _____mGy/Hour at a distance of 1 meter from the protective housing.

A

1

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19
Q

The SID indicator must be accurate to within_______________

A

2% of the indicated SID

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20
Q

The x-ray beam and light beam must coincide to__________.

A

2% of the SID

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21
Q

PBL must have an accuracy of ___________

2% of the SID

A

2% of the SID

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22
Q

The inherent filtration is _______________equivalent

A

0.5 mm of aluminum

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23
Q

The inherent and added filtration should combine to equal the required _________ equivalent.

A

2.5mm of aluminum

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24
Q

The variation in the x-ray intensity should not exceed___________________

A

5%

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25
The maximum acceptable variation in linearity is _________% from one mA station to an adjacent mA station.
10%
26
Radiation intensity is expressed in units of_____________
mR/mAs or mGy/mAs
27
The exposure switch must allow the operator to remain at least __________from the x-ray tube.
2 meters (6 feet)
28
The SSD must not be less than __________ cm on stationary fluoroscopes.
38
29
The SSD must not be less than___________ on mobile fluoroscopic equipment.
30 cm
30
The _____________________________ serves as a primary protective barrier and it must be ____________mm of lead equivalent.
Image intensifier, 2
31
The exposure switch should be of __________ type.
Dead man
32
The Bucky slot must be covered with at least __________mm of lead equivalent.
0.25
33
The protective curtain must be of at least __________mm of lead equivalent.
0.25
34
A cumulative timer must produce and audible signal when the fluoroscopic time has exceeded __________minutes.
5
35
How can you calculate DAP?
The absorbed dose multiplied by the tissue irradiated.
36
The intensity of the x-ray beam at the table top should not exceed ______ for each mA of operation at 80kVp (21mGy/min)
2.1 R/min
37
The intensity of the x-ray beam at the table top should not exceed ____ for regular fluoroscopy.
10 R/min
38
The intensity of the x-ray beam at the table top should not exceed ____ for High level fluoroscopy.
20 R/min
39
The Primary protective barrier thickness must be _________
1/16 inch of lead
40
Secondary protective barrier thickness must be ________
1/32 inch of lead
41
The intensity of scatter radiation at 1 meter from the patient is approximately _______% of the intensity of the useful beam at the patient.
0.1
42
An area that is occupied primarily by radiology personnel and patient is known as_________
A controlled area
43
Exposure to a radiation worker in the controlled area must be less that _____________/week
1mSv (100 mrem)
44
What is the annual recommended occupational dose limit?
50mSv
45
Exposure to personnel in the uncontrolled area must be less than _____________/week
2mrem
46
What is the unit for work load?
mA-minutes/wk
47
The percentage time during which the x-ray beam is on and directed toward a particular protective barrier is known as __________________
Use factor
48
__________ is the determination by scientific methods of the amount, rate and distribution of radiation emitted from a source of ionizing radiation.
Dosimetry
49
Name three field survey instruments.
Ionization chamber type survey meter Geiger-Mueller counters Scintillation detectors
50
Geiger-Mueller counter is a good measuring device.( True or False)
False
51
Which counter is generally used in Nuclear medicine?
Geiger-Mueller counter
52
What crystals are used in scintillation counter?
Sodium iodide or cesium iodide crystals
53
Most sensitive detector of alpha and gamma and x- radiation is_________________.
Scintillation
54
Which field survey equipment is useful in the detection of lost radiation sources?
Scintillation detectors
55
What is Dynode gain?
The ratio of secondary electrons to incident electrons.
56
What is hygroscopic means?
They absorb moisture and will swell and crack with the absorption of moisture.
57
A _____________________is a device that emits electrons when illuminated by __________.
Photocathode, light
58
_______________________is the process of emitting ___________by a photocathode when stimulated by ______________.
Photoemission, electrons, light
59
ESD can be calculated using a _______________.
Nomogram
60
Average ESD of fluoroscopy is ____________/min.
40mGy
61
The average radiation dose to the entire bone marrow is known as ___________________ dose.
Mean marrow
62
The US mean marrow dose is_____________________/year.
1mGy (100mrad)
63
Increased CT pitch increases patient dose.(True or False)
False
64
A pregnant patient is more sensitive during the __________semester
First
65
The natural background radiation in the US is _______mSv/yr.
3
66
More than 50% of the natural background radiation is from _______________
Radon
67
What is ALARA stands for?
As Low As Reasonably Achievable
68
Legal Dose Limits in the United States lens of the eye is__________
150 mSv/yr (15 rem/yr)
69
Legal Dose Limits in the United States during the entire pregnancy is __________________
5 mSv (500 mrem)
70
Legal Dose Limits in the United States for monthly pregnancy is
0.5 mSv (50 mrem)
71
What is TLD stands for?
Thermoluminescent Dosimeters
72
What crystal is used in a TLD?
Lithium Fluoride Crystals
73
Extremity dosimeter (Ring Dosimeter) used in Nuclear medicine is of ____________type.
Thermoluminescent Dosimeter
74
What is the minimum dose that can be measured using a TLD?
5 mrem
75
What is the minimum dose that can be measured using an OSL?
1 mrem
76
What is the minimum dose that can be measured using a Film badge?
10mrem
77
How long a TLD can be worn?
3 months
78
What is a disadvantage of a TLD?
Provide no permanent record
79
Which dosimeter is the most sensitive to low level radiation?
Pocket ionization chamber (Self Reading Dosimeter)
80
Which dosimeter should be charged to a predetermined voltage by a special charging unit?
Pocket ionization chamber (Self Reading Dosimeter)
81
Which radiation monitor can give immediate reading?
Pocket ionization chamber (Self Reading Dosimeter)
82
OSL contains a thin layer of __________detector.
Aluminum Oxide
83
What is the lowest level of radiation that can be measured using an OSL?
1 mrem

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