Physics Flashcards

(119 cards)

1
Q

EM radiation velocity?

A

3 * 10^8 m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the K shell binding energy of tungsten?

A

-69.5 keV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Relationship between Z and K shell binding energy

A

K shell binding energy is proportional to Z^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Relationship between xray production and mA

A

linear increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Relationship between xray production and kVp

A

Increasing kVp by 15% will double intensity of spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do you give to detect extrahepatic biliary atresia and how much

A

phenobarbitol
5 mg/kg/day
2 divided doses
3-5 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Half life of gallium

A

78hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Iso-osmolality iodinated contrast media

A

300 mOsm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

low-osmolality iodinated contrast media

A

600 mOsm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

high-osmolality iodinated contrast media

A

1200 mOsm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

human plasma

A

295 mOsm/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

CTDIw

A

1/3 CTDI central + 2/3 CTDI peripheral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

CTDIvol

A

CTDIw/Pitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Window levels for Brain

A

W 80, L +40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Window levels for Lung

A

W 1500, L -400

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Window levels for Abdomen

A

W 440, L +50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Window levels for Bone

A

W 1600, L +500

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Adult Head Avg Dose CTDI

A

58 mGy, effective dose (1-2 mSv)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Adult Abd CTDI

A

18 mGy, effective dose (8-11 mSv)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Peds Abd CTDI

A

15 mGy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

ACR “reference” dose, for which if they are above should be investigated:
CTDIvol for Head

A

75 mGy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

ACR “reference” dose, for which if they are above should be investigated
CTDIvol for Adult Abd

A

25 mGy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

ACR “reference” dose, for which if they are above should be investigated
CTDIvol for Peds

A

20 mGy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Embryo Dose in CT A/P

A

30 mGy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Individual dose monitoring mandated if occupational dose is greater than ___ of annual dose limit ____.
10%, 500 mrem
26
CT Head CTDIvol
CTDIvol of 60 mGy.
27
CT Head CTDIvol
CTDIvol of 60 mGy.
28
diagnostic workstation avg monitor brightnes
500 cd/m2
29
diagnostic workstation avg monitor brightnes
500 cd/m2
30
The instantaneous RF power (W) of a body coil in MR operated at 1.5 T is typically ____. However, remember that this RF is only switched on for the duration of a typical pulse (ms or so), so the energy consumption is not going to be large.
10000 W
31
The instantaneous RF power (W) of a body coil in MR operated at 1.5 T is typically ____. However, remember that this RF is only switched on for the duration of a typical pulse (ms or so), so the energy consumption is not going to be large.
10000 W
32
ultrasound mode A
echo intensity as a function of time or depth is A (Amplitude) display mode
33
ultrasound mode A
echo intensity as a function of time or depth is A (Amplitude) display mode
34
Which does not affect spatial resolution? Detector “size”, focal spot, and patient motion, radiation intensity?
radiation intensity ALWAYS affect spatial resolution performance, and nothing else dose (directly). Radiation intensity (number of photons), as such, is essentially irrelevant for resolution performance which means image blurriness, but will affect lesion visibility by impacting on mottle.
35
Which does not affect spatial resolution? Detector “size”, focal spot, and patient motion, radiation intensity?
radiation intensity ALWAYS affect spatial resolution performance, and nothing else dose (directly). Radiation intensity (number of photons), as such, is essentially irrelevant for resolution performance which means image blurriness, but will affect lesion visibility by impacting on mottle.
36
The maximum patient eye lens dose (mGy) after 5 minutes of fluoroscopy in interventional neuroradiology is likely___ Gy?
150 mGy
37
Which does not affect spatial resolution? Detector “size”, focal spot, and patient motion, radiation intensity?
ALWAYS affect spatial resolution performance, and nothing else dose (directly). Radiation intensity (number of photons), as such, is essentially irrelevant for resolution performance which means image blurriness, but will affect lesion visibility by impacting on mottle.
38
max patient eye dose after 5 min of fluro
150 mgy
39
max patient eye dose after 5 min of fluro
150 mgy
40
In cardiac ultrasound imaging, the pulse repetition period is most likely (ms):
0.25 ms, which corresponds to a Pulse Repetition Frequency of 4 kHz
41
listening period of cardiac ultrasound corresponds to penetration depth of
20 cm
42
listening period of cardiac ultrasound corresponds to penetration depth of
20 cm
43
frequency encoding gradient of single 128 x 196 Spin Echo MR image
128
44
frequency encoding gradient of single 128 x 196 Spin Echo MR image
128
45
sampling echo of single 128 x 196 Spin Echo MR image
196
46
sampling echo of single 128 x 196 Spin Echo MR image
196
47
The ideal fluoroscopic x-ray tube voltage in cardiac imaging is about ___ kV since this results in an average energy of ~35 keV that matches the k-edge energy of iodine contrast
he ideal fluoroscopic x-ray tube voltage in cardiac imaging is about 75 kV since this results in an average energy of ~35 keV that matches the k-edge energy of iodine contrast (Z = 53; k-edge 33 keV) that is ALWAYS administered to the patient to visualize the cardiac vasculature.
48
effective dose of chest CT
5 mSv
49
effective dose of CXR (1 ct = 100 CXR)
.05 mSv
50
effective dose of CXR (1 ct = 100 CXR)
.05 mSv
51
In chest CT, increasing the x-ray beam filtration would likely result in a lesion contrast that is
decreased
52
In chest CT, increasing the x-ray beam filtration would likely result in a lesion contrast that is
decreased
53
At the same techniques, increasing the patient size in chest CT from 70 kg to 100 kg will likely change the patient dose by (%):
decrease by 30%
54
At the same techniques, increasing the patient size in chest CT from 70 kg to 100 kg will likely change the patient dose by (%):
decrease by 30%
55
Which type of electronic (digital) correction is least likely to be applied to a gamma camera image? a. Energy Incorrect b. Sensitivity c. Linearity d. Septal penetration
septal penetration
56
Which type of electronic (digital) correction is least likely to be applied to a gamma camera image? a. Energy Incorrect b. Sensitivity c. Linearity d. Septal penetration
septal penetration
57
In chest MRI, doubling the duration of an RF pulse would likely cause the longitudinal Magnetization “flip angle” to be:
doubled
58
In chest MRI, doubling the duration of an RF pulse would likely cause the longitudinal Magnetization “flip angle” to be:
doubled
59
MP for clinical review station, MR/CT, general workstation, viewing mammogram
1 MP workstations are used in a clinician review station, 2 MP are used for MR/CT, 3 MP is a general purpose radiologists workstation (chest x-rays), and 5 MP is required for viewing mammogram
60
MP for clinical review station, MR/CT, general workstation, viewing mammogram
1 MP workstations are used in a clinician review station, 2 MP are used for MR/CT, 3 MP is a general purpose radiologists workstation (chest x-rays), and 5 MP is required for viewing mammogram
61
M mode imaging
echo intensities as a function of time has intensities about four times higher than in B mode imaging
62
M mode imaging
echo intensities as a function of time has intensities about four times higher than in B mode imaging
63
The average compressed breast thickness (mm) in the US is about ___ mm, which is much more that the ___ thick phantom that physicists currently use to measure mammography doses.
60 mm for avg breast | 42 mm for breast phantom
64
The average compressed breast thickness (mm) in the US is about ___ mm, which is much more that the ___ thick phantom that physicists currently use to measure mammography doses.
60 mm for avg breast | 42 mm for breast phantom
65
Energy deposited (joules) in the anode in an abdominal radiograph (100 kW; 0.1 s exposure) is most likely:
10,000 joules
66
Energy deposited (joules) in the anode in an abdominal radiograph (100 kW; 0.1 s exposure) is most likely:
10,000 joules
67
Increased bandwidth causes S:N to go up or down
makes S:N worse
68
Increased bandwidth causes S:N to go up or down
makes S:N worse
69
for every primary photon emerging from patient, there are _scatter photons
5
70
for every primary photon emerging from patient, there are _scatter photons
5
71
Coils: Gradient Shielding Shim
Gradient - spatial information Shielding - reduce magnitude of fringe magnetic field from main magnet Shim - improve homogeneity
72
halving FOV of collimation does what to spatial resolution
nothing
73
halving FOV of collimation does what to spatial resolution
Collimation generally does not change spatial resolution, or the Entrance Air Kerma
74
halving FOV of collimation does what to spatial resolution
Collimation generally does not change spatial resolution, or the Entrance Air Kerma
75
The minimum Focus to Skin Distance (cm) on a mobile fluoroscopy unit is ___ to make sure that the patient’s skin can’t get too close to the x-ray source.
30 cm | For fixed fluoroscopy units, this distance is 38 cm (FDA rules).
76
The minimum Focus to Skin Distance (cm) on a mobile fluoroscopy unit is ___ to make sure that the patient’s skin can’t get too close to the x-ray source.
30 cm | For fixed fluoroscopy units, this distance is 38 cm (FDA rules).
77
In extremity ultrasound, increasing the Pulse Repetition Frequency is unlikely to permit an increased:
imaging depth
78
In extremity ultrasound, increasing the Pulse Repetition Frequency is unlikely to permit an increased:
imaging depth
79
projection is all the ___ at a given rotational angle of the xray tube
rays
80
projection is all the ___ at a given rotational angle of the xray tube
rays
81
``` Which one does not reduce motion blur? increased: exposure time tube voltage tube current matrix size ```
``` exposure time everything else (voltage, current, matrix size) decreases blur ```
82
``` Which one does not reduce motion blur? increased: exposure time tube voltage tube current matrix size ```
``` exposure time everything else (voltage, current, matrix size) decreases blur ```
83
reducing image slice thickness has the biggest impact on what
thin slices will be NOISIER
84
reducing image slice thickness has the biggest impact on what
thin slices will be NOISIER | thin slices will not affect in plane resolution, only long axis resolution
85
reducing image slice thickness has the biggest impact on what
thin slices will be NOISIER | thin slices will not affect image contrast, in plane resolution, only long axis resolution
86
reducing image slice thickness has the biggest impact on what
thin slices will be NOISIER | thin slices will not affect image contrast, in plane resolution, only long axis resolution
87
replacing plastic apron (Z = 8) with lead equivalent apron (z=80) will increase abrosption of xrays by
1000 (bc mainly photoelectric interaction, Z^3)
88
replacing plastic apron (Z = 8) with lead equivalent apron (z=80) will increase abrosption of xrays by
1000 (bc mainly photoelectric interaction, Z^3)
89
CTDIvol is___ to scan length
indepdent CTDIvol is INDEPENDENT of scan length. CTDIvol tells you about the quality of an individual CT slice; the total amount of radiation that you use to perform the CT examination is the Dose Length Product (CTDIvol x Scan Length). The correct answer is: Independent of
90
CTDIvol is___ to scan length
indepdent CTDIvol is INDEPENDENT of scan length. CTDIvol tells you about the quality of an individual CT slice; the total amount of radiation that you use to perform the CT examination is the Dose Length Product (CTDIvol x Scan Length). The correct answer is: Independent of
91
fission products are most likely to emit
beta - emitters
92
fission products are most likely to emit
beta - emitters
93
antiscatter grid most likely seen at
bedside
94
antiscatter grid most likely seen at
bedside
95
S distortion in Image Intensifier fluoroscopic imaging is a result of extraneous:
mag field
96
S distortion in Image Intensifier fluoroscopic imaging is a result of extraneous:
mag field
97
The current US regulatory eye lens dose limit in interventional radiology (mSv/year) is
150 mSv
98
The current US regulatory eye lens dose limit in interventional radiology (mSv/year) is
150 mSv
99
Diagnostic workstation brightness is measured in
cd/m2, which is sometimes referred to as nits. A typical diagnostic workstation has a working brightness value of a few hundred cd/m2.
100
Diagnostic workstation brightness is measured in
cd/m2, which is sometimes referred to as nits. A typical diagnostic workstation has a working brightness value of a few hundred cd/m2.
101
In gamma cameras, the detected pulse height is ____ to the energy deposited in a gamma camera crystal (NaI).
In gamma cameras, the detected pulse height is directly proportional to the energy deposited in a gamma camera crystal (NaI). This is the basis of all Pulse Height Analysis.
102
In gamma cameras, the detected pulse height is ____ to the energy deposited in a gamma camera crystal (NaI).
In gamma cameras, the detected pulse height is directly proportional to the energy deposited in a gamma camera crystal (NaI). This is the basis of all Pulse Height Analysis.
103
SPECT and PET image reconstruction makes use of _____algorithm
SPECT and PET image reconstruction makes use of Iterative Reconstruction algorithm
104
SPECT and PET image reconstruction makes use of _____algorithm
SPECT and PET image reconstruction makes use of Iterative Reconstruction algorithm
105
Total Cardiac SPECT imaging time (minutes) is most likely:
15 min
106
Total Cardiac SPECT imaging time (minutes) is most likely:
15 min
107
Gamma cameras usually have ___PMTs
37
108
Gamma cameras usually have ___PMTs
37
109
nuclear isotopes have same number of__
protons
110
nuclear isotopes have same number of__
protons
111
If the parent is long lived, it is called +++; if the parent is short lived, it is called _____. The parent in the 99Mo/99mTc generator has a half-life of only 67 hours, so is called ____.
If the parent is long lived, it is called secular; if the parent is short lived, it is called transient. The parent in the 99Mo/99mTc generator has a half-life of only 67 hours, so is called transient. Note that equilibrium is established after 24 hours, which is four daughter half-lives.
112
If the parent is long lived, it is called +++; if the parent is short lived, it is called _____. The parent in the 99Mo/99mTc generator has a half-life of only 67 hours, so is called ____.
If the parent is long lived, it is called secular; if the parent is short lived, it is called transient. The parent in the 99Mo/99mTc generator has a half-life of only 67 hours, so is called transient. Note that equilibrium is established after 24 hours, which is four daughter half-lives.
113
Use of non-circular orbits in body SPECT imaging is most likely to result in images with improved:
resolution
114
Use of non-circular orbits in body SPECT imaging is most likely to result in images with improved:
resolution
115
Low energy collimators are made of __, whereas medium energy collimators are “_____” because these are much thicker. We do/do not collimators to image annihilation photons anywhere, but get positional information by detecting these photons in coincidence in PET cameras.
Low energy collimators are made of foil, whereas medium energy collimators are “cast” because these are much thicker. We don’t use collimators to image annihilation photons anywhere, but get positional information by detecting these photons in coincidence in PET cameras.
116
K shell binding energy of oxygen
0.5 keV
117
K shell binding energy of Lead
88 kev
118
K shell binding energy of Lead
88 kev
119
k shell beinding energy of iodine and barium
33 and 36 keV