Radiology Cafe Appendix (Erin) Flashcards
1
Q
What is the equation for maximum number of electrons in a shell?
A
2n2 (n = shell number)
2
Q
What is the equation for Intensity (E) of a photon
A
E= hf (h = planks constant)
3
Q
As frequency increases what happens to the energy of a photon
A
Increases
4
Q
What is the equation for intensity relative to distance
A
1 / d2 (d = distance)
5
Q
What is the equation for photoelectric LAC
A
Photoelectric LAC = ρZ3 / E3 (ρ = density, Z = atomic number, E = energy)
6
Q
What is the equation for Compton LAC
A
Compton LAC = ρ / E
7
Q
What is the equation for Mass attenuation coefficient
A
LAC/p
8
Q
What is the equation for the linear attenuation coefficient
A
Linear attenuation coefficient (LAC, cm-1) = 0.693 / HVL
9
Q
What is the equation for factor of reduction relating to HVL
A
Factor of reduction = 2HVL (HVL = half value layer)
10
Q
What colour of light is used to read out CR plates
A
Red light
11
Q
What colour of light is released when CR plates are read out
A
Blue light
12
Q
What material is the scintillation layer in indirect DR plates made from
A
caesium iodide with thallium (CsI:Tl)
13
Q
What is the maximum compression used in mammography
A
200N
14
Q
What is the typical compression used in mammo
A
100-150N
15
Q
What is the image plate in computed radiography made from
A
barium fluorohalide activated with divalent europium ions.
16
Q
In indirect DR what colour of photons are released from the scintillation layer
A
Green
17
Q
In indirect DR how many light photons are produced per xray photon
A
3000 light photons in the green spectrum
18
Q
In indirect DR what is the matrix made from
A
amorphous silicon layer doped with hydrogen (a-Si:H)
19
Q
What is the focus to film distance used in mammo
A
65-66cm
20
Q
What size is the broad focal spot in mammo
A
0.3mm
21
Q
What size is the fine focal spot in mammo
A
0.1mm
22
Q
What material of target/filter is commonly used in mammo
A
Mo/Mo
23
Q
What material of target/filter is commonly used in mammo for larger breasts
A
Mo/Rh
Rh/Rh
24
Q
In fluoroscopy what is the input window made from
A
aluminium of titanium foil
25
What material is used as the input phosphor in fluoro
Sodium activated caesium iodide (CsI:Na)
26
How thick is the Sodium activated caesium iodide (CsI:Na) used in fluoro?
400-500 μm thick
27
What colour photons does the input phosphor create in fluoro
Blue
28
What material is the photocathode made from in fluoro
Antimony caesium (SbCs3)
29
What material is the output screen made from in fluoro
Silver-activated zinc cadmium sulphide (ZnCdS:Ag)
30
What is the equation for G brightness in fluoro
Gbrightness = Gminification x Gflux (Gminification = minification gain; Gflux = flux gain)
31
What is the equation for G minification in fluoro
Gminification = (Dinput / Doutput)2 (Dinput = diameter of input screen; Doutput = diameter of output screen)
32
What is the atomic number of tungsten
74
33
What is the mass number of tungsten
184
34
What is the K alpha characteristic radiation of Tungsten
59.3 keV
35
What is the K beta characteristic radiation of tungsten
67.6 keV
36
What is the K alpha characteristic radiation of Molybdenum
17.5 keV
37
What is the K beta characteristic radiation of Molybdenum
19.6keV
38
What is the K edge of Mo
20keV
39
What is the K alpha and K beta characteristic radiation of Rhodium
Kα = 20.2 keV
Kβ = 22.7 keV
40
What is the K edge of Rh
23.3 keV
41
What 3 factors improve geometrical unsharpness
Small focal spot size
Increasing focus to detector distance
Decreasing object to detector size
42
What is the equation for multislice pitch in CT
Multislice pitch = beam pitch = couch travel per rotation / total width of simultaneously acquired slices
43
What is the equation for single slice pitch in CT
Single slice pitch = detector pitch = couch travel per rotation / detector width
44
What is the fine focal spot size used in CT
0.7mm
45
What is the broad focal spot size used in CT
1.0mm
46
What is the CT number of water
0
47
What is the CT number of fat
-50 to -100
48
What 2 factors increase maginification
increased object to detector distance
decreased focus to detector distance
49
What is the CT number if air
-1000
50
What is the CT number of bone
+1000
51
What is the CT number of CSF
15
52
What is the CT number of white matter
20 to 30
53
What is the CT number of grey matter
37 to 45
54
What is the CT number od liver
40-60
55
How is dose measured in CT
mAs/pitch
56
What is meant by CTDI
Dose to the detector from single gantry rotation
57
What unit is CTDI measured in
mGy
58
What is meant by Weighted CTDI
(CTDIw) in CT
Adjusted for spatial variation of dose
⅓ CTDIcentre + ⅔ CTDIperiphery
59
What is the definition of CTDI vol in CT
Accounts for pitch
CTDIw / pitch
60
What unit if CTDIw and CTDIvol measured in
mGy
61
What does DLP stand for in CT
Dose Length Product
62
How is DLP calculated
Total dose along distance scanned
CTDIvol x distance scanned
63
What is the range of audible soundwaves
Audible range of soundwaves = 20 to 20,000 Hz
64
What is the range of waves used in medial ultrasound
Medical ultrasound = 2 to 18 MHz
65
Equation for velocity in USS
Velocity (c) = √ ƙ / ρ (ƙ = rigidity; ρ = density)
66
What is the speed of ultrasound in soft tissue
Speed of sound through tissue = 1540 ms
67
What is the resolution of film screen radiograph
6lp/mm
68
What is the resolution of digital radiograph
3lp/mm
69
What is the resolution of digital mammography
5-10 lp/mm
70
What is the resolution of fluoroscopy
5lp/mm
71
What is the resolution of fluoroscopy flat panel detector
3lp/mm
72
What is the effective dose of a CTAP
10mSv
73
What is the effective dose of a barium enema
7mSv
74
What is the effective dose of CT colonography
6mSv
75
What is the effective dose of CT head
2 mSv
76
What is the effective dose of a CT spine
6mSv
77
What is the effective dose of CT neck
3mSv
78
What is the effective dose of CT chest
7 mSv
79
What is the effective dose of a CXR
0.1 mSv
80
What is the effective dose of an XR pelvis
0.5mSv
81
What is the effective dose of mammography
0.4 mSv
82
What is absorbed dose
Energy deposited per unit mass of tissue
83
What unit is absorbed dose measured in
Gray
84
What is the effective dose
sum of (equivalent dose x tissue weighting factor)
85
What is the equivalent dose
sum of (Absorbed dose x radiation weighting factor)
86
What is the average background radiation/year
2.7mSv/year
87
What is the average background radiation from natural sources
2.3 mSv/year
88
What is the average background radiation from medical exposure
0.4 mSv/year
89
What is the radiation weighting factors of xrays, gamma rays, beta particles and positrons
1
90
What is the radiation weighting factors of alpha particles
20
91
What is the radiation weighting factor of neutrons 100keV-2MeV
20
92
What is the radiation weighting factor of Neutrons <10keV
5
93
What does ALARP stand for
As low as reasonable practicable
94
Is ALARP under IRR or IRMER
Both
95
What is the role of IRMER
Governs all medical and non-medical exposures to patients
96
What is the effective dose limit per year to a radiation worker >18yrs
20mSv per year
97
What is the effective dose limit per year to members of the public
1mSv per year
98
What is the effective dose limits to radiation workers <18yrs
6mSv per year
99
What is the effective dose limit to carers/comforters
5mSv per year
100
What is the effective dose limit for pregnant employees
1mSv for remainder of pregnancy
101
What is the dose limit to abdomen of person of reproductive capacity
13mSv in any consecutive 3 months
102
What is the equivalent dose limit to lens of the eye for employees >18yrs
20mSv
103
What is the equivalent dose limit to lens of the eye for employees<18yrs
15mSv
104
What is the equivalent dose limit to lens of the eye for any other person
15mSv
105
What is the equivalent dose limit to extremities for employees>18yrs
500mSv
106
What is the equivalent dose limit to extremities for employees<18yrs
150mSv
107
What is the equivalent dose limit to extremities for any other person
50mSv
108
What is the equivalent dose limit to skin for employees >18yrs
500mSv
109
What is the equivalent dose limit to skin for employees <18yrs
150mSv
110
What is the equivalent dose limit to skin for any other person
50mSv
111
At what effective dose does someone need to be a classified worker
>6mSv/year (i.e 3/10 of the dose limit which is 20mSv)
112
At what equivalent dose dose someone need to be a classified worker
Equivalent dose >3/10 of any dose limit
i.e >15mSv to lens of eye
>150mSv to skin or extremities
113
What classifies an areas as a controlled area
Area where staff likely to receive effective dose >6mSv
15mSv equivalent dose to eyes
Or >3/10 of any relevant dose limit
External dose rate exceeds 7.5uSv/hr over working day
Dose rate <7.5uSv/h over working day BUT instantaneous dose rate at ANY point exceeds 100uSv/h
114
What classifies an areas as a supervised area
Person working in area likely to receive dose of >1mSv/yr
Or equivalent dose of >1/10 any relevant dose limit
115
What does MARS78 govern
administration of radioactive substances
116
What does RSA govern
storage and safe disposal of radioactive materials
117
What does Radioactive Material (Road Transport) (Great Britain) Regulation 2001 govern
governs transport of radioactive substances by road
118
What is the MHRA guidelines for whole body exposures of patients in MRI (normal and pregnant) in Tesla
4 Tesla
119
What is the MHRA guidelines for whole body exposures of patients in MRI (controlled) in Tesla
8 Tesla
120
What is the MHRA guidelines for whole body exposures of patients in MRI (research purposes) in Tesla
No limit
121
What is the MHRA guidelines for exposure of staff for whole body (in Tesla)
<2 Tesla for whole body
122
What is the MHRA guidelines for exposure of staff for limbs (in Tesla)
<5T for limbs
123
124
At what gauss is an MRI area controlled
5 gauss
0.5mT boundary
125
What is the lead equivalence of lead aprons for 100kV and 150kV
0.25mm for 100kV
0.35mm for 150kV
126
What is the lead equivalence in mm of thyroid shield
0.5mm
127
What is the lead equivalence in mm for lead glasses
0.25 x 1.0mm
128
What is the lead equivalence for lead gloves in mm
0.5-1.0 mm (modern gloves)
Old gloves 0.25 mm
129
Can a person be the referrer, practitioner and operator
yes
130
What is the role of the referrer (IRMER)
Health care professional entitled in accordance with employer's and local procedures to request and refer individuals for medical exposure
Need to supply practitioner with sufficient medical information
131
What is the role of the practitioner (IRMER)
Required to justify all medical exposures and decide if exposure is in patient best interest (e.g person who vets requests)
Can be radiologists or radiographer
132
What is the role of the operator (IRMER)
Carried out and optimises the medical exposure
ALARP
133
What is the role of the employer (IRMER)
Implements IRMER and allocated individuals with roles
Provides written procedures and protocol
Ensures staff are trainer
Responds to incidents
134
What is the risk of cancer per 1mSv in adults
1 in 20,000
135
Does effective dose concern deterministic of stochastic effects
Stochastic effects
136
Does equivalent dose concern deterministic or stochastic effects
Deterministic
