Cheat sheet Flashcards
1
Q
I-123 Normal A? Mode of decay principle energu physical half life
A
53
Electron capture
159keV
13.2h
2
Q
Str-89 Normal A? Mode of decay principle energu physical half life
A
38
Beta - Yttrium 89
None
50d
3
Q
O-15 Z? Mode of decay principle energu physical half life
A
8
B+ (neutron poor) - N15
173keV
2 minutes
4
Q
F-18 Z? Mode of decay principle energu physical half life
A
9
B+ (neutron poor) - O18
635keV
110min
5
Q
Mo-99 Z? Mode of decay Principle energy Physical half life
A
42
B- (neutron excess) - Tc-99m
740keV
67h
6
Q
I-131 Z? Mode of decay Principle nergy physical half life
A
53
B- (neutron excess) –> Xe-131
364keV
8d
7
Q
Tc99 Z? Mode of decay Principle energy Physical half life
A
43
Isomeric transition
140keV
6 hours
8
Q
What are half lives: Tc99 F18 Io131 Co57
A
Tc - 6.0h
F18 - 110min
I131 - 8.0d
Co57 - 271.8d
9
Q
Wavelength of violet light
A
380-450nm
10
Q
Wavelength of blue light
A
450-500
11
Q
Wavelength of green light
A
500-570
12
Q
Yellow light wavelength
A
570-590
13
Q
Orange light wavelength
A
590-620
14
Q
Red light wavelength
A
620-750
15
Q
UV light wavelength
A
400-10nm
16
Q
X-ray wavelength
A
0.01-10nm
17
Q
Gamma ray wavelength
A
10^-12
18
Q
US frequency
A
2-20MHz
19
Q
Gamma ray frequency
A
10^19Hz
20
Q
Ca
Z?
K-edge?
A
20
4.5keV
21
Q
Iodine
Z?
K-edge?
A
53
34.5keV
22
Q
Barium
Z?
K-edge?
A
56
40.4keV
23
Q
Cesium
Z?
K-edge?
A
55
38.9keV
24
Q
Tungsten
Z?
K-edge?
A
74
69.5keV
25
Lead.
Z?
K-edge?
82
| 93.1keV
26
Bismuth
Z?
K-edge?
83
| 95.7keV
27
Yttrium
Z?
K-edge?
39
| 17keV
28
Gadolinium
Z?
K-edge?
64
| 50.2keV
29
Molybdenum
Z?
K-edge?
42
| 21keV
30
Law of transformers in regards to # of turns?
Np/Ns = Vp/Vs
31
Law of transformers in regards to voltage?
VpIp = VsIs
32
Conversion efficiency of CaWO4 vs rare earth screens?
CaWO4 - 5%
| Rare earth = 20%
33
Absorption efficiency of film, CaWO4 or rare earth screens?
Film - 1%
CaWO4 = 20%
Rare earth = 40-60%
34
Optical density equation
```
OD = log (1/T)
OD = log (Io/I) = without a film/with a film
```
35
Calculation of transmittance?
T = I/Io
| With a film/without a film
36
Deterministic effects?
- Practical threshold – below this dose – no effects occur
- Severity increases with dose – degree of change increase with dose
- Skin erythema, sterilization, cataracts
37
Stochastic effects?
- Severity is independent of dose
- No threshold
- Probability increases with dose
Examples: hereditary effects, cancer
38
Transient equilibrium?
Parent's T1/2 is 10x that of daughter
| Equilibrium reached in 3.8 daughter T 1/2
39
Secular equilibrium
Parent's T1/2 is 100x that of daughter
| Equilibrium reached in 5-6 daughter T1/2
40
How do you calculate magnification?
L image / L object
A+B/B
A = source to object
B = object to film
41
How do you calculate true magnification?
M = m + (m-1)/(f/d)
42
How do you calculate the penumbra?
```
Lg = Lf (b/a)
B = object to film distance
A = source to object
```
43
How do you calculate the penumbra?
```
Lg = Lf (b/a)
B = object to film distance
A = source to object
```
44
Typical pixel format and bits/pixel for:
Planar gamma camera
Matrix: 64 or 128
| Bits/pixel: 8 or 16
45
Typical pixel format and bits/pixel for:
Digital radiography
Matrix: >2000
| Bits/pixel: 12-16
46
Typical pixel format and bits/pixel for:
fluoroscoxpy
512 or 1024
| 12 bits/pixel
47
Typical pixel format and bits/pixel for:
CT
512
| 12 bits/pixel
48
Typical pixel format and bits/pixel for:
MRI
64 to 1024
| 12 bits/pixel
49
Typical pixel format and bits/pixel for:
US
512
| 8 bits/pixel
50
Limiting spatial resolution:
Screen film
0.08mm
51
Limiting spatial resolution:
Digital radiography
0.17mm
52
Limiting spatial resolution:
Fluoro
0.125mm
53
Limiting spatial resolution:
CT
0.3mm
54
Limiting spatial resolution:
Nuc med
2.5mm
55
Limiting spatial resolution:
SPECT
7mm
56
Limiting spatial resolution:
MRI
1mm
57
Limiting spatial resolution:
US
0.3mm
58
Thickness of PZT?
| High frequency vs low frequency?
1/2 wavelength
Low frequency = thicker crystals
High frequency = thinner crystals
59
What is the q-factor?
Q = center frequency / bandwidth
Describes bandwidth of sound emanating from a transducer and length of time it persists
60
Describe a low Q factor
Useful for pulse imaging (tissue)
Better receivers
Heavy damping - resulting in short SPL/short ring-down, and an impure sound (broad bandwidth)
Improved spatial resolution
61
Describe a high Q factor
```
Useful for pulsed Doppler imaging
Better transmitters
Light damping - long ring-down that results in a long SPL
Pure sound (narrow bandwidth)
Decreased spatial resolution
```
62
How thick is the matching layer?
1/4 the wavelength
63
What is the pulse repetition frequency?
```
# of pulses/s in kHz - 2-4kHz
Pulses = SPL (# of cycles x wavelength) - usually 3 total wavelengths
```
64
How is PRF related to frame rate?
PRF = frame rate x # of echo lines x FR
65
What is the maximal range of a pulse?
77,000/PRF
66
What is the pulse repetition period?
Time from the beginning of one pulse to the next
Inverse of the PRF
PRP = 1/PRF
Increase the PRF - will decrease the PRP
67
When do you need to use a lower PRF?
Low frequency transducers - have increased depth - need more time to listen for returning echoes (range ambiguity artifact may occur)
68
What is the pulse duration?
Time if takes for 1 pulse to occur
Ratio of # of cycles in the pulse to transducer frequency
# of cycles/pulse divided by transducer frequency
69
What happens to pulse duration if the frequency is increased?
Pulse duration will decrease
| Period will also decrease
70
What is the duty factor?
Fraction of 'on' time
Pulse duration / PRP
71
What does a higher PRF do to the duty factor?
Duty factor = pulse duration / PRP
Higher PRF = smaller PRP = higher duty factor
Using a higher frequency transducer = more on-time... has less penetration and does not need to wait for returning echoes
72
What is the spatial pulse length?
What does determine?
SPL = wavelength x # of cycles
Typically - 2-3 cycles per pulse
1/2 SPL = axial resolution
73
What is a typical duty factor for real time imaging?
0.2-0.4% the rest is in listening mode
