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Physics & Image Production Flashcards

1
Q
  1. PACS stands for:
  2. PACS Functions:
  3. DICOM stands for:
  4. DICOM Functions:
A
  1. Picture Archiving & Communication System
  2. Maintain Image, Storage & Viewing between systems
  3. Digital Imaging & Communication in Medicine
  4. Computer language alloqs all PACs to communicate
    • “Standard Language”
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2
Q
  1. EMR Stands for:
  2. EMR Functions:
  3. EHR Stands for:
  4. EHR Functions:
A
  1. Electronic Medical Record
  2. Track all medical & clinical data gathered in office SINGLE OFFICE
  3. Electronic Health Record
  4. Allows charing info between offices MULTIPLE OFFICE
    • Ex: EPIC
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3
Q

3 Ways PACs servers can network with imaging & reading stations:
1. Name: _____, Pros: ______ & Cons:______
2. Name: _____, Pros: ______ & Cons:______
3. Name: _____, Pros: ______ & Cons:______

A
  1. Server-Based: Sent direct ti PACs system * interpreted
    • Pros: All images can be accessed from any PACs server
    • Cons: Runs on 1 network & easily slowed down, PACs fails = entire system fails
  2. Web-Based: Same as server but images can be accessed anywhere, No dedicated PACS
    • Pros: Exams accessed from anywhere
    • Cons: Still need PACS & entire system speed depend on internet speed
  3. Distribution-System: Images sent to PACS & Duplicated to specific reading station
    • Pros: If main down, can see duplicated images
    • Cons: Need to ensure correct exams sentt
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4
Q
  1. Types of Circuits: _________ & _________
  2. Components of Circuits: _________, ________, _________ & _______
  3. What is Ohm’s law used to find? (5)
A
  1. Series & Parellel
  2. Resistor, Ohms, Voltage & Amperage
  3. Total Voltage Gain, Total Resistance, Total Current, Voltage Drops & Current Through Resistor
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5
Q
  1. ________ - Electrical component that inhibits flow of current through a circuit.
  2. Measured In: ________
  3. _______ - Provides electrical potential/power to circuit
  4. _________ - Decrease of electrical potential along current flow path in circuit
A
  1. Resistor (R) (Designed to reduce flow of current)
  2. Ohms
  3. Voltage (V)
  4. Voltage Drop
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6
Q
  1. ______ - Unit of measure represents degree of resistance between 2 points of conductor within circuit
  2. ______ - Measurement of Electrical current
  3. Above also referred to as:
  4. Voltage Total = ________
A
  1. Ohms
  2. Amperage (A)
  3. Intensity
  4. Voltage Total = Sum of all voltages in circuit
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7
Q
  1. What is a resistor measured in?
  2. Amperage also referred to as:
  3. What are the images showing:
  4. What does a resistor do to current in circuit?
A
  1. Ohm
  2. Intensity
  3. Image A: Series Circuit
    Image B: Parallel Circuit
  4. Decreases voltage / reduce flow
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8
Q

1.Difference between series circuit & parallel circuit?
2. What does a break in circuit cause in each?

  1. Ohms Law is used to calculate: ____, ____ & _____
  2. Ohms Triangle Law States:
A
  1. Series: All parts connected in continuous line
    Parallel: Current able to flow beyond continuous line (has multiple paths)
  2. Break in series = circuit fails
    Break in parallel = circuit still able to function
  3. Voltage, Ampere or Resistance (Ohm)
  4. V = I x R
    R = V / I
    I - V / R
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9
Q
  1. _______ - Flow of electrons in electrical current
  2. _______ - Difference in charge (positive & negative)
  3. Two Types of Currents: _________ & _______
  4. X-Ray Tube Current is:
A
  1. Current
  2. Voltage
  3. Direct Current (DC) & Alternating Current (AC)
  4. Direct Current used in xray (cathode to anode)
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10
Q
  1. In Direct Currents Electrons Flow:
  2. In Alternating Current Electrons Flow:
  3. Why does x-ray tube use direct current?
  4. How is alternating current created?
A
  1. One direction (like a battery)
  2. Rapid back & forth / changing directions
  3. So electrons flow in one direction, cathode - anode
  4. Through specialized generators (change charges - making electrons flow in different directions)
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11
Q
  1. X-Ray Circuit Current Used Is:
  2. Transformers function in electrical current is:
  3. Three parts of transformer: _____, ________ & ________
  4. Transformer functions by:
A
  1. Alternating Current
  2. Change voltage (polarity)
  3. Iron Core, Primary Coil & Secondary Coil
  4. Electromagnetic Induction (no moving parts)
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12
Q
  1. Do Transformers increase or decrease voltage?
  2. Electricity in Primary coil vs Secondary coil:
  3. Explain how transformer is functioned by electromagnetic induction:
A
  1. Both
  2. Primary = electricity in
    Secondary = electricity out
  3. Magnetic field induces current flow between primary & secondary side
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13
Q
  1. In a transformer, current increases or decreased based on:
  2. This determines:
  3. What is Turns Ratio?
  4. Formula for Turns Ratio
A
  1. # of turns/windings on each side
  2. If it is step-up transformer or step-down transformer
  3. # of turns on secondary side, divided by # turns on primary side
  4. (image)
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14
Q
  1. Which side of a transformer has higher voltage?
  2. If a primary coil has 10 turns, and a secondary coil has 5 turns
    - What type of transformer is this?
    - Does voltage decrease or increase?
  3. What part of x-ray system uses step-up transformer? step down?
A
  1. The side with more turns has more voltage
    • Step Down
      - Voltage decreases by half
  3. High-Voltage Section requires step-up (v->kV)
    • Filament circuit to get mA cathode side of tube (creating electrons)
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15
Q

Step-Up Transformer:
1. _____ Voltage While _____ Amperage
2. Changes ______ to _______
3. More primary or secondary turns?
4. Part of x-ray system used?

A
  1. increase voltage while decrease amperage
  2. volts to kilovolts
  3. More secondary turns (ratio greater 1)
  4. Tube potential (kV)
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16
Q

Step-Down Transformer
1. _____ Voltage While _____ Amperage
2. Changes ______ to _______
3. More primary or secondary turns?
4. Part of x-ray system used?

A
  1. decrease voltage while increasing amperage
  2. changes amps to milliamps (A -> mA)
  3. More primary turns
  4. Filament circuit (creation of electrons)
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17
Q
  1. What is the Turns Ratio for a transformer with 40 primary turns and 4000 secondary turns?
  2. Is it step-up or step-down?
  3. What is the voltage produced by a transformer receiving 220V, if primary side has 100 turns and secondary has 10,000 turns?
  4. Is it step-up or step-down?
A
  1. Ns / Np (Secondary divided by primary)
    - 4000 / 40 (plug in numbers)
    - 100 / 1 (divide above to get 100:1)
    - Turns Ratio is 1
  2. Step-Up because Turns Ratio is 1
    —————————————————-
  3. Vs / Vp = Ns / Np
    (secondary voltage divide by primary voltage = secondary turns divided by primary turns)
    - x / 220 = 10,000 / 100 (plug in numbers known)
    - x(100) = 220 (10000) - cross multiply
    - 100x = 2,200,000 - (result of step above, now divide 100 from each side)
    - x = 22,000V (result from step above)
    - 22,000V on Secondary Side
  4. 22,000V on Secondary Side = Step Up Transformer
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18
Q
  1. How does an autotransformer work?
  2. Does it do step-up or step-down?
  3. What does it change in?
  4. How many coils?
A
  1. Self-Induction
  2. Both step-up & step-down
  3. Small changes to voltage only
  4. 1 Coil around a single core
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19
Q
  1. How does an autotransformer determine step-up or step down?
  2. How is turns ratio changed in autotransformer?
  3. How does step-up, step down & autotransformers work compared to each other?
  4. How does step-up, step down & autotransformers make changes compared to each other?
A
  1. Determined by turns ratio
  2. Changed by using kVp selector
  3. Step-Up: Works by MUTUAL Induction
    - Step Down: Works by MUTUAL Induction
    - Autotransformer: Works by SELF Induction
  4. Step-Up: Makes large changes to voltage
    (V -> kV)
    - Step Down: Makes large changes to voltage
    (A -> mA)
    - Autotransformer: Makes small changes to voltage (can do both step-up & step-down)
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20
Q
  1. How does step-up, step down & autotransformers change voltage & amperage compared to each other?
  2. Transformers in X-Ray Circuit Order:
    A. _________ (Name & What Does or Changes)
    B. _________ (Name & What Does or Changes)
    C. _________ (Name & What Does or Changes)
    D. _________ (Name & What Does or Changes)
    E. _________ (Name & What Does or Changes)
A

1.Step-Up: Increase Voltage & Decrease Amperage
- Step Down: Decrease Voltage & Increase Amperage
- Autotransformer: Can do both step-up & step-down
2. A. Wall Power Supply (220V)
B. Autotransformer (V ->V)
(220V -> 85V)
C. Step-Up Transformer (V->kV)
(85V -> 85,000V [85kVp])
D. Rectifier Bridge (AC->DC)
(AC->DC)
E. X-Ray Tube
(85 kVp)

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21
Q
  1. Transformers in Filament Circuit Order:
    A. _________ (Name & What Does or Changes)
    B. _________ (Name & What Does or Changes)
    C. _________ (Name & What Does or Changes)
    D. _________ (Name & What Does or Changes)
  2. _______ - Converts Alternating Current to Direct Current.
  3. Which transformer is used in x-ray circuit?
  4. Which transformer is used in the filament?
A
  1. A. Wall Power Supply (220V)
    B. Autotransformer (V ->V)
    C. Step-Down Transformer (A -> mA)
    D. Cathode Filament
    (Heat for Thermionic Emission)
  2. Rectifier
  3. Step-Up
  4. Step-Down
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22
Q
  1. Rectifiers convert _____ to ______
  2. Most common rectifier in xray?
  3. With rectifiers, electrons flow _________
  4. Where are rectifiers located? why?
A
  1. Alternating Current to Direct Current (AC-DC)
  2. Solid-State Diode
  3. Only 1 Direction
  4. Between Step-Up Transformer & X-Ray Tube
    - Because transformers need AC, but x-ray tube needs DC
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23
Q
  1. Do transformers need Alternating current or direct current?
  2. _________ - Polarity of voltage rapidly changes back & forth (electrons flow in multiple directions)
  3. _________ - Electrons flowing in reverse direction are blocked (electrons only flow one direction)
  4. Compare Half-Wave & Full-Wave Rectifiers in regards to their gaps & flow direction.
A
  1. Alternating
  2. Unrectified
  3. Rectified
  4. Half-Wave: Other wave is blocked & gap has no electron flow
    • Full-Wave: Back-flow is NOT blocked, & there are no gaps between pulses
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24
Q
  1. In a Half-Wave Rectifier, Gaps have _______-, where in a Full-Wave Rectifier, Gaps are _______.
  2. Which rectifier changes electron polarity? What does this do?
  3. _______ - Number of Distinct Wave Cycles in Circuit
  4. ________ - Number of voltage pulses per cycle
A
  1. Half = no electron flow / xray creation
    - Full = nonexistent (no gaps between pulses)
  2. Full-Wave changes electron polarity so that it flows in same direction
  3. Phase
  4. Pulse
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25
1. In a circuit, Pulse is dependent on: 2. ______ - Describes number of pulses 3. Voltage Ripple for Generator Type: - Single Phase = - 3 Phase, 6 Pulse = - 3 Phase, 12 Pulse = - High Frequency (HF) = 4. What is desired for xray? why?
1. Phase & Rectifier 2. Frequency 3. Single = 100% - 14% - 4% - HF = 1% 4. High Voltage, because you want constant output for x-rays & least ripple
26
1. What is voltage waveform? 2. What is desired in x-ray? why? 3. What is Voltage Waveform Ripple? 4. How is it calculated?
1. VW plots voltage over time 2. For constant production of x-rays, constant high-voltage is desired 3. Fluctuations in voltage output of generator 4. Maximum Voltage - Minimum Voltage = % Ripple
27
1. What Phase(s) are show in the images? 2. Are they rectified? 3. What is the Voltage Ripple? 4. How many waveforms present?
1. IMAGE 1: Single Phase - IMAGE 2: Single Phase, One Pulse (Half-Wave Rect.) 2. IMAGE 1: Unrectified - IMAGE 2: Half Rectified (Can tell by wave going below line in image 1 vs wave going flat in image 2) 3. IMAGE 1: 100% VR - IMAGE 2: 100% VR (Can tell because peaks of wave go all way to 0 before next wave in both images) 4. IMAGE 1: 1 Distinct Waveform - IMAGE 2: 1 Distinct Waveform (Can tell by only one line shown in image)
28
1. What Phase(s) are show in the images? 2. Are they rectified? 3. What is the Voltage Ripple? 4. How many waveforms present? 5. How many pulses demonstrated?
1. IMAGE 1: Three Phase Single Pulse - IMAGE 2: 3-Phase 6-Pulse Full Wave Rect. 2. IMAGE 1: Unrectified - IMAGE 2: Full Rectified (Can tell by wave going below line in image 1 vs wave bouncing / not going flat in image 2) 3. IMAGE 1: Reduced VR - IMAGE 2: 14% VR (Can tell because where one wave drops off, next picks up in image 1 & Image 2, small 14% gap between top of one wave & crossing of next) 4. IMAGE 1: 3 Distinct Waveform - IMAGE 2: 3 Seperate Waveform (Can tell by how many lines shown in image) 5. IMAGE 1: Single Pulse - IMAGE 2: 6 Pulses (Can tell by how many waves go from 0, peak & backdown - aka how many bumps)
29
1. What Phase(s) are show in the images? 2. Are they rectified? 3. What is the Voltage Ripple? 4. How many waveforms present? 5. How many pulses demonstrated?
1. IMAGE 1: Three Phase Twelve Pulse Full-Wave Rect. - IMAGE 2: High Frequency (HF) 2. IMAGE 1: Full Rectified - IMAGE 2: N/A (Can tell by wave not going flat in image 1, just bounce to next & image 2 has no significant drop) 3. IMAGE 1: 4% VR - IMAGE 2: 1% VR (Can tell because small 4% gap between top of one wave & crossing of next in image 1 & image 2 is basically straight line 4. IMAGE 1: 3 Separate Waveform - IMAGE 2: Single Distinct Waveform (Can tell by how many lines shown in image) 5. IMAGE 1: 12 Pulses - IMAGE 2: Thousands of Pulses (Can tell by how many waves go from 0, peak & backdown - aka how many bumps)
30
LABEL THE X-RAY CIRCUIT & WHAT IT DOES BEIGE = DARKER BLUE = LIGHTER BLUE =
1. MAIN BREAKER / POWER - BRINGS POWER TO CIRCUIT 2. EXPOSURE SWITCH - STARTS EXPOSURE 3. AUTOTRANSFORMER - ALLOWS KVP / SELECTS KVP 4. TIMER CIRCUIT - ENDS EXPOSURE 5. HIGH VOLT. STEP-UP TRANSFORMER - INCREASES VOLTAGE 6. RECTIFICATION CIRCUIT - CONVERTS AC TO DC 7. VARIABLE RESTISTANCE - CONTROLS AMPERAGE /MA 8. FILAMENT STEP-DOWN TRANSFORMER - WARMS FILAMENT & INCREASES THERMIONIC EMISSION 9. X-RAY TUBE - PRODUCES X-RAY 10. ROTOR / STATOR - USES AC TO INDUCE ELECTRICITY
31
1. LABEL THE X-RAY CIRCUIT COLORS: BEIGE = DARKER BLUE = LIGHTER BLUE = 2. BOTH BLUES TOGETHER = MAIN CIRCUIT 3. WHAT IS INCLUDED IN LIGHT BLUE SIDE? 4. WHAT IS INCLUDED IN DARK BLUE SIDE? 5. WHAT IS INCLUDED IN BEIGE?
1. BEIGE = FILAMENT CIRCUIT - D.BLUE = SECONDARY SIDE (HIGH VOLTAGE) - L. BLUE = PRIMARY SIDE (LOW VOLTAGE) 2. MAIN XRAY CIRCUIT 3. PRIMARY CIRCUIT INCLUDES MAIN BREAKER, EXPOSURE SWITCH, AUTOTRANSFORMER, TIMER CIRCUIT, HIGH-VOLTAGE STEP UP TRANSFORMER 4. SECONDARY CIRCUIT INCLUDES RECTIFIER, XRAY TUBE & ROTOR/STATOR 5. VARIABLE RESISTOR & FILAMENT STEP- DOWN TRANSFORMER
32
1. What voltage or amperage is primary circuit? - Secondary circuit? - Filament circuit? 2. What components are in the primary circuit? 3. What components are in secondary circuit? 4. What components are in filament circuit?
1. Primary = low Voltage (V) - Secondary = High Voltage (kV) - Filament = High Amperage (mA) 2. P= Power Supply, Circuit Breaker, Autotransformer, kVp Selector, Exposure Meter, Primary Side of Step-Up Transformer 3. S= Secondary side of step-up transformer, Rectifier bridge (AC-DC), X-Ray Tube 4. F = Rheostat & mA Selector, Step-Down Transformer & Cathode Filament
33
1. What is function of circuit breaker? 2. What is kVp Meter measured in? Why? 3. What controls Exposure Timer? 4. What does Rectifier Diode change?
1. Protects circuit from power surges or shorting 2. Measured in Volts because easy to read & convert to kV 3. Controlled by Time Setting or AEC 4. Changes AC to DC, Polarity Change, & Wave Rectifier
34
1. Cathode Filament creates _____ via ________ 2. X-Ray Tube needs _____ current & _____ Voltage 3. What is function of Rheostat? AKA?
1. Cathode creates free electrons via Thermionic Emission 2. Direct Current & High Voltage 3. Sets mA to be sent to filament & controls filament heat/current for Thermionic Emission * mA SELECTOR*
35
1. Tube Housing Main Functions: - Made Of: 2. Glass Envelope Functions: - Location:
1. Prevents xrays from being emitted throughout room - Absorb xrays not aimed at patient (prevent leakage & off-focus radiation) *MADE OF METAL OR LEAD* 2. Air-Free Vacuum - Protects tube from oxidation/corrosion (extends tube life) - Around cathode & anode
36
ANODE: Charge: Function: Made Of / Why:
Charge: POSITIVE Function: ATTRACTS NEG. CHARGED ELECTRONS, ABSORBS ELECTRONS & CREATES X-RAYS Made Of: TUNGSTEN & RHENIUM (HIGHER HEAT CAP.)
37
CATHODE: Charge: Function: Made Of / Why:
Charge: NEGATIVE Function: CREATES FREE ELECTRONS Made Of: TUNGSTEN FILAMENT
38
1. What interactions occur at Tungsten target? 2. What type of anode is used in x-ray & why> 3. What is function of induction motor? - How does it work? 4. Where is induction motor located? - What does it consist of?
1. Bremsstrahlung & Characteristic 2. Rotating b/c allows higher heat capacity & larger focal track 3. Turns rotating anode without making contact - Works like magnet, pushing opposing charges against each other 4. Located in x-ray tube, by anode - STATOR, ROTOR & BEARINGS
39
1. Where does rotor function? - Where does it attach? 2. What is Stator & its function? - Where located? 3. What are Bearings & Function? - Where located 4. What is filament consist of? - What is its function?
1. Inside glass envelope - To Anode Disk / apart of induction motor 2. Electromagnet surrounding rotors - induces turning of rotor - OUTSIDE of glass envelopes - apart of induction motor 3. Low friction spheres allow free rotation of rotor - Around rotor / apart of inductor motor 4. Small tungsten wire coil - Source of free electrons
40
1. Where is filament located? 2. What is function of focusing cup? - How does it work? 3. What does focusing cup effect? 4. What is Thermionic Emission? - Where does it occur?
1. Cathode 2. Holds cathode filament to focus electron beam - Electrons & Focus cup is negatively charged, propelling & focusing electron stream to Anode 3. Spatial Resolution (Tight Electron Beam = Tight X-Ray Beam) 4. Process of heating filaments to create free electrons (from heated metal = releases electrons) - In Cathode Filament
41
1. What is Space Charge? 2. What is Space Charge Effect? 3. How many size filaments are in cathode? 4. What do filament sizes effect?
1. Current goes through filament it gets hot creating cloud of free electrons / charged particles are in space 2. There is limit to electrons produced at cathode - number of electrons increase with mA 3. 2 - small (1cm) & large (2cm) 4. Spatial Resolution
42
1. COMPARE FILAMENTS SMALL: - AKA: - HEAT CAPACITY: - SPATIAL RESOLUTION: - STUDIES USED FOR: LARGE: - AKA: - HEAT CAPACITY: - SPATIAL RESOLUTION: - STUDIES USED FOR:
1. SMALL: - AKA: SMALL FOCAL SPOT - HEAT CAPACITY: SMALL mA (HEAT CAPACITY) - SPATIAL RESOLUTION: HIGHER - STUDIES USED FOR: SMALL EXPOSURES / BODY PARTS LARGE: - AKA: LARGE FOCAL SPOT - HEAT CAPACITY: LARGER mA (HEAT CAPACITY) - SPATIAL RESOLUTION: LOWER, LESS ALIGNED BEAM - STUDIES USED FOR: LARGER mA / BODY PARTS
43
1. Is beam quantity lower on Anode or Cathode side? 2. Common angles of Anode: 3. Relationship between Anode Heel Effect & Anode Angle: 4. Which angle is preferred to reduce anode heel effect?
1. ANODE (FAT CAT) 2. 6-20* 3. INVERSE (Greater the angle, less heel effect, Lesser the angle, greater heel effect) 4. LARGER ANGLE
44
1. Relationship between Anode Heel Effect & SID: 2. Relationship between Anode Heel Effect & Field Size: 3. ________ - Describes relationship between actual focal spot on target anode & effective focal spot size 4. Smaller anode angle is used to reduce ________
1. INVERSE (Larger SID = less anode heel, Smaller SID = greater anode heel) 2. DIRECT (Large IR size = greater anode heel, smaller IR = lesser anode heel) 3. Line-Focus Principle 4. Effective area of focal spot
45
1. Which size focal spot is better for fluro? mammo? why? 2. What is different between Actual Focal Spot vs Effective Focal Spot?
1. Fluro = Large Focal Spot b/c requires large exposure output and large field sizes - Mammo = Small Focal Spot b/c high spatial resolution 2. Actual - on Anode / target where heat is produced when electrons beam hits it from cathode filament - Effective - Origin of effective xray beam. Where photons that were created at actual focal spot are projected at 90*
46
1. Changing anode angle changes _______ 2. Where is actual focal spot? 3. Where is effective focal spot? 4. What is Line-Focus Principle describe? - Describe:
1. size of effective spot 2. actual on anode where electron beam hits from cathode 3. 90* from actual, origin of effective beam 4. Relationship between anode angle & effective focal spot ( - Smaller Anode Angle = Smaller Effective Focal Spot = Increased Spatial Resolution )
47
1. Line Focus Principle States: _____ Anode Angle = ____ Effective Spot = ____ S.R. 2. Most photons are created at: 3. _______ - Created by electron interactions in tube away from anode focal spot 4. What is leakage radiation?
1. Smaller / Smaller / Greater 2. At actual focal spot on tungsten target 3. Off-Focus 4. it is form of scatter / no diagnostic purpose. It is when an off-focus photons leave tube,
48
1. What limits leakage radiation? 2. How much of prime beam consists of off-focus radiation? 3. With Increased Leakage Radiation: _____ Patient Dose = ____ Spatial Resolution = ____ Contrast 4. How do you reduce patient exposure to leakage radiation?? - How do you reduce it to IR exposure?
1. Protective Housing 2. Less than 1% 3. Increased Leakage = Increased patient dose, decreased spatial resolution & decreased contrast 4. Shielding protects patient - Shuttering / Collimating protects exposure to IR
49
1. What is tube loading? 2. X-Ray creation is made of: ____ & _____ 3. What happens if anode overheats? 4. What is Heat Units calculate? - Formula?
1. Heat created within x-ray tube especially at anode 2. 99% heat & 1% x-ray 3. Anode can melt or rupture x-ray assembly 4. Calculated to avoid damage to tube assembly - HU = kVp x mAs x W (W = Wave form factor: see image)
50
1. What does wave form factor account for? 2. What is Wave Form Factor for: -Single Phase: - 3 Phase-6 Pulse: - 3 Phase -12 Pulse: - High Frequency:
1. Accounts for type of generator & rectification of system being used 2. -Single Phase: 1 - 3 Phase-6 Pulse: 1.35 - 3 Phase -12 Pulse: 1.41 - High Frequency: 1.45
51
1. What is HU = kVp x mAs x W calculate? 2. What 4 variable affect Heat Capacity? 3. What is Anode Cooling Chart used for? 4. What are the axis' of Anode Cooling Chart?
1. Heat Unit (HU) to avoid damage to the tube assembly 2. A. Exposure Time & mA (mAs) B. Filament Size & Focal Spot Size C. Anode Angle D. Anode Rotation Speed 3. Used to calculate how much time is needed between exposure for anode to cool enough for additional exposures be made safely 4. Vertical (Y) Axis: Heat Units (In thousands) Horizontal (x) Axis: Time (mins)
52
1. Exposure Time & Heat Capacity: _____ Time = ____mA = _____ Heat Capacity - Desired: 2. Filament Size & Heat Capacity: _____ Filament Size = _____ Focal Spot Size = _____ Heat Capacity - Desired: 3. Anode Angle & Heat Capacity: _____ Anode Angle = ____ Focal Spot Size = _____ Heat Capacity - Desired: 4. Anode Rotation & Heat Capacity: _____ Rotation = _____ Heat Concentration = _____ Heat Capacity - Desired:
1. Inc. Exposure Time = Decr. mA = Inc. Heat Cap. - Increased time & lower mA = Better Heat Cap 2. Larger Filament = Larger Focal Spot = Greater Heat Cap - Large Filament/Focal Spot for larger exposure & more heat spread 3. Larger Anode Angle = Larger Focal Spot = Heat Capacity - Larger anode angle spreads out heat / allows more absorption 4. Greater Rotation Speed = Less Heat Concentration = Greater Heat Cap. - Faster rotation means heat is less concentrated & anode has greater capacity
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1. X-Ray beam is made up of how many photons? 2. X-Ray Photon -Energy: -Charge: -Speed Travel: 3. Are x-rays & light similar? why or why not?
1. Millions 2. -Energy: Lots of Energy -Charge: No mass/charge -Speed Travel: Speed of Light (velocity never changes) 3. Both apart of electromagnetic spectrum
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1. What is included in Electromagnetic Spectrum? 2. What is wavelength? - Relationship with energy? 3. What is frequency? - Relationship with energy? 4. Desired wavelength, frequency & energy for x-ray:
1. Radiowaves, microwaves, infrared, visible light & gamma rays 2. Distance from peak to peak in photon wave - As distance decreases, energy increases 3. Number of wave cycles per second - Frequency increases, Energy increases 4. Short wavelength, high frequency, high energy
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1. Energy of X-Ray Beam is: 2. Majority of x-ray beam formed by ________ interaction, and small portion of ______ interactions 3. _______ - Number of xrays - AKA: 4. _______ - Average energy of xray photons
1. Polyenergetic (millions of photons with different energies) 2. Bremsstahlung Mostly & Charachteristic slightly 3. Quantity / Intensity 4. Quality
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1. What does it mean that X-Ray is created Isotropically? 2. How do X-Ray beam travel? 3. Beam Quantity is also known as: 4. What is Beam Quantity?
1. X-Rays diverge equally in all directions 2. Diverges in straight lines and keep going until something stops them 3 Intensity of Beam 4. Number of photons in beam
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1. Quantity / Intensity of beam is controlled by: - Other factors include: 2. Measurements of Beam Quantity/Intensity: 3. Quality is also known as: 4. What is Beam Quality?
1. mA controlling - kVp, Exposure time, distance & filtration influence 2. Exposure (C/kg) & Air Kerma (Gy) 3. Penetrability 4. Average energy of all xray photons in beam
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1. What is mA is? - _____ mA = _____ Quantity 2. kVp affects: - _____ kVp = ______ Quantity = _______ Quality 3. What is the exposure time? - ____ time = _____ quantity 4. Where is intensity higher? - does it effect the energy? - _____ distance = ____ quantity
1. Tube Current ( Higher current = higher quantity ) - higher mA = higher quantity 2. increased kVp = increased quality & increased quantity 3. Time electrons flowing in tube & xrays being created - increased time = increased quantity 4. Closer to source - doest effect energy - increased distance = decreased quantity
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1. What does filtration do? - _____ filtration = _____ quality = _____ quantity 2. Exposure measured in: 3. Air Kerma measured in: 4. What does keV measures:
1. Removes low energy photons from beam / increases average energy of beam - incr. filtration =. incr. quality = decr. quantity 2. Coulombs Per Kilogram (C/kg) 3. Gray (Gy) 4. kiloelectron volts measure Beam quality
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1. Controlling factor of beam quality: - Also effected by: 2. Three things required for x-ray production: - & Where does it occur? 3. Interactions occur with tungesen atoms in anode are: 4. Beam Penetrability is measured in:
1. kVp - Filtration 2. A. Source of electrons (thermionic emission at cathode filament) B. Means of rapid acceleration of electrons (kVp - tube potential) C. Means of rapid deceleration of electrons (Anode Target - source of xray photons) 3. Bremstrauglung & Charachteristic 4. keV - kiloelectron volts
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1. Bremsstrahlung Radiation is also known as: 2. Where does it occur? 3. Three steps of interaction: 4. Calculating Brem's Xray Photon Formula= 5. Maximum Energy of Brem's X-Ray is:
1. Braking Radiation 2. Occurs with Tungsten atom at anode 3. A. Incoming electron interact with field of atoms NUCLEUS (negative e- attract to positive nucleus) - B. Incoming e- slows (brakes) & changes direction, some energy is lost and creates Brem's x-ray photon (energy of photon depends on how close to nucleus, closer = more energy lost) - C. Incoming electron leaves with remaining energy in different direction 4. Incoming Electron Energy - Outgoing Electron Energy = X-Ray Energy 5. Maximum energy same as tube potential
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1. Energy of Brem's photon depends on: - Relationship: 2. Five Steps of Characteristic Radiation: 3. Calculating characteristic x-ray photon energies formula:
1. how close to nucleus the electron gets - Closer to nucleus the electron gets, more energy lost by electron 2. A. Incoming electron collides with inner shell electron B. Inner shell electron knocked out orbit, leaving vacancy C. Outer shell electron drops down to fill void & stabalize inner shell D. Every time electron drops down, characteristic photon created E. Incoming electron then leaves 3. Difference between shell binding energies = characteristic xray energies - (Inner Shell Binding Energy - Outer Shell Binding Energy)
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1. Inner Most Shell of an atom is: 2. Tungsten inner shell binding energy: 3. To knock out an electron, energy of incoming electron must be: 4. Characteristic Radiation makes up __ % of primary beam
1. k-shell (then goes L, M, N, etc.. outward) 2. 69.5 keV 3. incoming electrons must be higher then binding energy of electron 4. Small Amount / Small %
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1. What interaction is demonstrated? 2. Which interaction involves nucleus? 3. Which interaction involves inner shell electron? 4. Which interaction has a maximum energy?
1. Brem. Interaction (incoming electron interacts with field of nucleus, produces photon in one direction & electron continues in another) 2. Brems 3. Charact. 4. Charact has max energy of binding energy - Brem's has no min or max
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1. What is attenuation? 2. What are 4 things attenuation depends on? 3. ______ - X-Ray beam coming from tube before interacts w patient 4. What interaction is demonstrated in image?
1. Reduction in x-ray beam intensity as result of absorption & scatter in matter 2. A. Part Thickness - B. Tissue Density - C. Atomic # - D. Beam Energy (kVp) 3. Primary Beam 4. Characteristic (Incoming electron interacts with inner shell electron / knocking it out. Outer shell moves down to replace & creates photon while original electron is projected out)
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1. _______ - Attenuated beam / what is remaining in beam after passes through matter (patient) 2. What are the 3 things occur when x-ray beam passes though matter that contribute to attenuation? 3. Is Attenuation greater or lesser with: - The thicker the patient's part: - The More Dense the part: - Higher atomic #: - Higher Beam energy:
1. Remnant Beam 2. Transmission, Absorption & Scatter 3. Thicker - More Scatter & More Attenuation - More Dense = More Mass = More Attenuation - Higher Atomic # = More Attenuation (Bone v Tissue) - Higher Beam Energy = Penetrate more = attenuate less
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1. Difference between Primary Beam vs Remnant Beam: 2. X-Ray Beam Interacts w. matter, what occurs in: - Transmission - Absorption - Scatter 3. 3 Interactions between X-Ray Photon & Matter:
1. Primary = before interacting with patient, Remnant = After interacting with patient 2. Transmission: Photons pass through patient / no interaction occurs - Absorption = Photons absorbed by patient completely - Scatter = Photons interact w matter & scatter out of beam in diff. directions 3. Coherent/Classical, Compton/Incoherent & Photoelectric Absorption
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Coherent/Classical Scatter 1. How often does it occur? 2. Occurs at what level energy? 3. Does ionization occur? 4. Is there any effect on patient, bystander & Image quality? 5. In vs Out:
1. Least likely of all interactions 2. Low photon energy (Less than 100keV) 3. No ionization 4. no effect on patient (no energy absorbed / no biological harm) - no effect on bystander (scatter forward / not backward) - Slight effect on image quality (Scatter decreases contrast & adds noise) 5. Photon In --> Photon Out
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Compton/Incoherent Scatter: 1. How often does it occur? 2. Occurs at what level energy? 3. Does ionization occur? 4. Is there any effect on patient, bystander & Image quality? 5. In vs Out:
1. Most Common Interaction 2. All energy levels (main interaction at high levels) 3. Ionization occurs 4. Increases patient dose (damages surrounding tissue) - Bystander: increased dose (scatter in different directions) - Image Quality: Decreases ( scatter adds noise to image & decreases contrast) 5. Photon In -> Electron & Photon Out
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1. Which interactions result in ionization? 2. Two Steps of Coherent Scatter: 3. Three steps of Compton Scatter: 4. Three Steps Photoelectric Absorption:
1. Compton Scatter & Photoelectric Absorption 2. A. Photon initially absorbed by atom B. Energy of photon ejected as photon with same energy, in diff directions 3. A. Photon partially absorbed in atom by outer shell - B. Ionization occurs, compton electron ejected - C. Remaining photon energy carried away as scatter photon with less energy 4. A. Photon completely absorbed by inner shell - B. Ionization occurs, electron ejected (photoelectron) - C. Atom unstable / creates characteristic photon
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1. What interaction is demonstrated? 2. Where does it occur? 3. Which interaction results in an ejected electron? 4. Which interactions occur at high energy? - Low energy?
1. Coherent / Classical Scatter 2. Photon interacts in patient ( atom in pt) 3. Compton & Photoelectric = ejected electron 4. Compton is main at high level - Classical, Compton & Photoelectric occur a low energy
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Photoelectric Absorption: 1. How often does it occur? 2. Occurs at what level energy? 3. Does ionization occur? 4. Is there any effect on patient, bystander & Image quality? 5. In vs Out:
1. Main interaction 2. Low energy levels 3. Ionization occurs 4. Patient = Increases Patient Dose (absorbed ionized e- causing damage to tissue) - Bystander: No effect (absorbed by patient) - Image = Benefits image quality (different attenuations/absorptions create contrast)
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1. mA is measure of _______ 2. When are x-rays produced? 3. Exposure time is measured in: 4. Intensity of beam formula:
1. Tube Current 2. When electrons at cathode filament travel & collide with target anode 3. Seconds 4. Tube Current x Exposure Time (mA x s = mAs)
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1. What is Tube Current? 2. _______ Current = ______ Amperage, - Meaning: 3. Primary factor of Tube Current: 4. Increased Amperage = - ______ Tube Current - ______ Electron Flow - _______X-Rays - _______ Intensity (# photons in beam) -________Receptor Exposure (# photon reach IR) -_________ Patient Dose
1. Movement of electrons from cathode to anode 2. Higher Current = Higher Amperage (# electrons flowing through tube) 3. mA (NOT mAs **) 4. Inc amperage = - inc. tube current - inc electron flow - inc. x-rays - incr. intensity - incr. IR exposure - incr. patient dose
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1. What is reciprocity law? 2. When would you used short exposure time? - long exposure time? 3. What accelerates electrons & pushes them across tube & to anode? 4. What is Tube Potential? - Measured in?
1. Describes relationship between mA & time & total mAs - mA & time have reciprocal relationship, MEANING no matter what combination of mA & time - total will be same 2. Short = Reduce Motion - Long- Blur anatomy (use w.orthostatic breathing) 3. kVp 4. Difference in charge between cathode & anode - Measured in kVp
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1. What is kiloelectrons volts? 2. What happens when you increase kVp? 3. Increasing kVp = - ______Energy (Quality) - ______Intensity (Quantity) - ______Patient Dose - ______Receptor Exposure - ______Image Contrast
1. Unit of measure that quantifies energy of photons 2. Setting MAX energy of photon in beam, it causes electrons to move more quickly which creates higher energy x-ray beam. 3. Increasing kVp = - Inc. Energy (Quality) - Inc. Intensity (Quantity) - Inc. Patient Dose - Inc. Receptor Exposure - Decr. Image Contrast
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1. What does it mean that the x-ray beam is divergent? 2. Relationship between distance & intensity? 3. What does the Inverse Square Law State? - Formula: 4. Increasing Distance = - ______ Intensity (Quantity) - ______ Patient Dose - ______ Receptor Exposure
1. More intense concentrated photons closer to source, and they spread apart & become less intense as they travel 2. INVERSE ( Inc. SID, Decr. Intensity) 3. Intensity of x-ray beam is inversely proportional to square of the distance of object from source * Initial Intensity divided by new intensity = New distance divided by initial distance * 4. Increasing Distance = - Decr. Intensity (Quantity) - Decr. Patient Dose - Decr. Receptor Exposure
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1. What can AEC help with? 2. What factors does AEC select? - What factors does tech select? 3. When does AEC stop exposure? 4. With AEC, how can you adjust amount of exposure allowed?
1. Get right exposure for quality image 2. AEC selects length of exposure (therefore mAs) - Tech selects kVp & mA 3. When sufficient receptor exposure is recieved 4. ONLY by density settings
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1. What is purpose of ionization chamber? 2. Other name(s) for ionization chamber? 3. What is Minimum Response Time? 4. What is Maximum Response Time?
1. Measure amount of exposure IR receiving 2. AEC Cell, Photo-Timer or Radiation Detector 3. Shortest exposure time (.001 s) 4. Back-Up Timer (150% or 600mAs) stops exposure no matter what to help prevent overexposure to patient
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1. What is most important with AEC? - What results if not correct? 2. What is only factor affects both quality & quantity of x-ray beam? 3. What interactions contribute most to photon interaction within matter? 4. What interaction is shown?
1. Positioning & Correct Cell Selection - Incorrect will cause AEC to shut off too soon or too late, resulting in over or under exposure image 2. kVp 3. Compton Scatter & Photoelectric absorption 4. Bremsstraahlung
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1. CR Stands for: DR Stands for: 2. Does CR use cassette? Does DR use cassette? 3. What is a latent image? 4. What is Phosphor layer made of?
1. CR = Computed Radiography - DR = Digital Radiography 2. CR uses cassette - DR does not use cassette 3. Recorded image stored in a plate 4. Mostly Barium Fluorohalides
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1. What is type / name of CR cassette? 2. Outer cassette is made of ________ - Function: 3. Layers of CR Cassette: A. __________ - Protect phosphor layer B. __________ - Contains Bromides which store & release energy C. __________ - Grounds imaging plate, absorbs light D. __________ - Protects Plate E. __________ - Prevents unwanted light/radiation from affecting latent image F. __________ - Protection & prevent unwanted light to image
1. Photo-Stimulable Phosphor (PSP) Plate 2. Carbon Fibers - Protect inner layers 3. A. Protective B. Phosphor C. Conductive D. Support E. Reflective Layer F. Protective Backing
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1. What is function of Imaging Plate Reader? - AKA: 2. What Radiography uses this? (CR OR DR) 3. What is Raster Pattern? 4. What type of laser is used in the reader?
1. Device used to release stored latent image & convert it to digital image for display - DIGITIZER 2. CR 3. Read Left to Right, Line by Line ( like we read a text) 4. Helium Neon Laser
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Steps to Digitizer in CR: 1. 2. 3. 4. 5. 6.
1. Rollers extract image 2. Helium Neon laser reads in Raster Pattern 3. Phosphors in plate release stored energy in form of light when hit by laser 4. Photo-Multiplier (PMT) collects & amplifies light photons to make brighter *** Charged Couple Device is alternative to PMT&ADC*** 5. Amplified light photons sent to Analog to Digital Converter (ADC) where converted to digital signal 6. Imaging plate exposed to bright flourescent light that releases any remaining latent image
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1. What is CCD? - When used? 2. What is used to release latent images left on plate after scanned in reader? 3. When should you process an imaging plate after an exposure? Why? 4. How does a laser work in a digitizer?
1. Charged Coupling Device - replaces PMTs / amplifies light in imaging plate 2. Fluorescent light 3. AS SOON AS POSSIBLE - Prevent latent image loss 4. Laser is split, passes through focusing lens then reflects off a mirror to read plate
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1. DR Stands for: 2. Does DR use a cassette? 3. Types of DR:
1. Digital Radiography 2. No cassette or reader used in DR 3. Direct & Indirect
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Indirect Conversion in DR 1. Types: 2. Converts ____ to _____, then to ___________ Direct Conversion in DR 3. Types: 4. Converts _____ to ______
1. TFT or CCD 2. Xray to light to electrical charge 3. non-scintillator 4. xrays to electrical charge
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1. TFT Stands for - Used in? 2. TFT Scintillation layer made of _________ - Function: 3. TFT Photodiode made of ______ - Function: 4. TFT made of _______ 5. DEL active element ________ - Function:
1. Thin Flat Panel Transistor - DR Indirect Conversion 2. Cesium Iodide (CSI) or Gadolinium (Gd) - Photons interact w. scintillator & create light 3. Amorphous Silicon - Semiconductor converts light into electrical charge 4. Array of Detector Elements (DEL) 5. DEL active element is Pixel - storage capacitor stores electrical charge from capture element & switch to release
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1. CCD stands for: - Used in: 2. CCD Scinitilator Layer function: 3. What is a sensor chip? - used in?
1. Charges coupling device - Used in DR Indirect conversion (also can be used in CR to replace PMT) 2. CCD scint. optically coupled to each sensor chip by lens or fiber optics 3. Converts light photon to electrical charge AND sends to computer as digital signal for processing -CCD in Indirect DR
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1. Semiconductor layer in direct conversion: - How it Works: 2. TFT function in Direct Conversion DR: 3. What is Cesium Iodide and Gadolinium? - What uses them? 4. What is difference between Amorphus Silicon & Amorphus Selenium? - What is similar?
1. Amorphus Selenium - High volt charge applied across surface before exposure, selenium atoms release electrons 2. Collects electrical charge and send to computer 3. Scintilators that create light from photons - Used in TFTs in Indirect DR 4. ASi. is photdiode used in indiret TFT DR - ASe is used in Direct DR - BOTH are semiconductors in DR
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1. Compare Indirect DR (TFT/CCD) to Direct DR 2. What uses scintillators? 3. Does DR or CR use TFT?
1. Indirect: Extra step converting photon to light to electrical charge - uses scintilators (Cesium Iodide & Gadolinium) - Photodiode is Amorphus Silicon Direct: Converts photon to electrical charge - no scinitilators - Photodiode is Amorphus Selenium 3. BOTH USE TFT (Thin Flat Panel Transistor)
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1. What is Field of View? 2. What is Digital Matrix? 3. What are Pixels? 4. What is Matrix Size? 5. What is Pixel Size?
1. Diameter of area being imaged that is being represented by display image 2. Square arrangement of rows and columns made up of collections of pixels 3. Picture elements, each tiny squares make up an image represents a single shade of grey 4. Number of pixels within a matrix 5. Size of individual pixel (FOV / MATRIX SIZE = PIXEL SIZE)
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1. Common Matrix Size in Imaging: - _____x______ or __________ pixels 2. Larger Matrix = ______ Pixels. & _____ Spatial Res. 3. How to determine size of pixel? 4. Smaller FOV = _____ pixel size = _______ Spatial Res.
1. 1024x1024 or 1,048,576 pixels 2. Large Matrix = More Pixels = Better S.R 3. FOV divided by Matrix size = pixel size 4. Smaller FOV = decreased pixel size = better spatial res.
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1. ______ Matrix = ______ Pixels = _____ Pixel Size = Increased Spatial Resolution 2. _____ FOV = _______ Pixel Size = Increased Spatial Resolution 3. What is Spatial Resolution? (3 definitions)
1. Large Matrix, More Pixels, Smaller Pixels 2. Small FOV, Small Pixels 3. Structural Sharpness RECORDED in image - Ability of imaging system to differentiate between adjacent structures - A measure of smallest detail that can be recorded by system
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1. What is Low Visibility? 2. High Resolution = _____ Lines, ____ Detail, ______ Blur & ____ (#) Pixels 3. Low Resolution Results: 4. What is spatial resolution measured in?
1. Structural sharpness that is recorded but difficult to see due to motion or scatter 2. Sharp structural lines, high detail, no blur & more # pixels 3. increased blur & unclear anatomical edges 4. Line Pairs per millimeter (lp/mm)
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1. What is line pair per millimeter? 2. Larger lp/mm represent _______ 3. Based on images, from LEFT to RIGHT, scale: matrix size, pixel size & spatial resolution 4. Which side is better / desired?
1. Measure of spatial frequency / resolution 2. smaller detail between adjacent objects * Inc. lp/mm = In Spatial Resolution 3. LEFT SIDE has larger matrix, smaller pixels & higher spatial res. RIGHT SIDE has smaller matrix, larger pixels & lower spatial res. 4. LEFT SIDE DESIRED
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1. Equipment Factors & Spatial Resolution Relationships: A. Matrix Size: B. Pixel Size: C. Pixel Pitch: D. DEL Size: E. DEL Pitch:
A. Large Matrix: Matrix Size Increases, Pixel Size Decreases, Spatial Res Increases B. Smaller Pixels = More Pixels =Spatial Res. Increases C. Smaller Pixel Pitch = More Pixels = Spatial Res. Increases D. Smaller DEL Size = More DELs/Pixels = Spatial Res. Increases E. Smaller DEL Pitch = More DELs/Pixels = Spatial Res. Increases
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1. What is pixel pitch? 2. What is relation between pixel pitch & size? 3. What is DEL? 4. What is DEL Pitch? 5. What is relation between DEL pitch & size?
1. Distance between center of one pixel to center of the next 2. Smaller distance between means smaller pixel 3. DEL is detector element in DR receptor, where pixels are the active element within 4. DEL Pitch is center of one DEL to center of next DEL 5. Smaller DEL Pitch (smaller distance between) means smaller DELs
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1. With Spatial Resolution, what Equipment Factors affect it & what is desired for increased spatial resolution? 2. What is most common cause of low spatial resolution/low visibility? 3. What are procedural factors that effect spatial resolution?
1. A. Matrix Size (LARGE) B. Pixel Size (SMALL) C. Pixel Pitch (SMALL) D. DEL Size (SMALL) E. Del Pitch (SMALL) 2. Motion 3. Motion & Beam Alignment (OID, SID & FSS)
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1. If photons are not aligned, the object is: 2. How does OID affect spatial resolution? - Longer OID vs Shorter OID: 3. How does SID affect spatial resolution? - Longer SID vs Shorter SID 4. How does Focal Spot Size affect spatial resolution? - What FSS is preferred / Why?
1. Not projected to same place on IR 2. Divergence of beam as it passes anatomy before IR - Longer OID gives more space for diverge before IR - Shorter OID gives less divergence of beam before IR 3. SID affect alignment of photons near center of beam - Longer SID photons more aligned to center - Short SID allows wide divergence of beam 4. Focal Spot Size affect alignment of beam from anode to anatomical structure - Smaller focal spot produce more aligned beam
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1. What is Focal Spot Blur? - Formula for: 2. With Spatial Resolution, what procedural factors affect it and what are desired for increased spatial resolution? 3. What procedural factors do NOT affect spatial resolution? - what do they affect?
1. Blur caused by FSS - Focal Spot Blur = FFS x (OID divided by SOD) 2. A. OID (SHORTER) *Less Divergence of Beam* B. SID (LONGER) *Less Divergence of Beam* C. FSS (SMALLER) *Beam aligned from anode to structure* D. Motion (SMALL/NONE) *Less/No Motion = No Blur/Noise* 3. kVp, mAs, Grids, Filtration & Collimation - Don't affect recorded detail but CAN decrease visibility of recorded detail by increasing quantum mottle or scatter
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1. What is bit depth? 2. What is another term for brightness level? 3. How do you calculate bit depth? 4. What does a large bit depth mean?
1. Total number of possible brightness levels (shade of gray) that can be assigned to any pixel in image 2. Grayscale 3. 2^Bit (2 to the power of bit) = shades of gray 4. More shades gray, long grayscale, better detail
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1. What bit depth is desired? Why? 2. What is quantization? 3. Process of Quantization 4. What determines contrast resolution? -What is desired / why?
1. Large bc more shades of gray can be displayed = better detail 2. Conversion from electrical to digital in which brightness levels (bit depth) are assigned * BRIGHTNESS LEVELS ASSIGNED 3. Electrical signal from IR converted to digital bits (0 & 1s) in ADC (analog digital converter) 4. Bit depth determines level of brightness and contrast resolution - Large Bit Depth = Higher Brightness Levels = Better Contrast Resolution
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1. What is contrast resolution? - What is its controlling factor? 2. What is dynamic range? 3. If range is low: - if range is high:
1. Smallest exposure differences that can be detected and displayed by imaging system - Bit Depth 2. Range of exposures that can be captured by detector 3. Low Exposure = no image captured or QUANTUM MOTTLE High Exposure = SATURATION (a lot of black on image b/c more radiation than can be processed)
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1. When does Quantum Mottle Occur? 2. What is saturation? - When does it occur? 3. What is exposure latitude? 4. What is it compared to Dynamic range?
1. Noise due to Low / insufficient exposure 2. More radiation exposure than can be processed, looks very black on image - Over exposure 3. Range of exposures that produce quality image at appropriate patient dose 4. Smaller area of techniques within dynamic range that produce quality image
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1. Do higher exposures within exposure latitude provide a more optimal image? 2. What is Dose Creep? 3. Low contrast demonstrates _________ difference in brightness & ______ shades of gray 4. High Contrast demonstrates ______ difference in brightness & ______ shades of gray
1. Not always / only provides more pt dose 2. gradual increase in exposure factors by radiographers in attempt to produce better x-rays at negative consequence to patient 3. LOW = small differences, many shades (little black & white) 4. HIGH = obvious differences, few shades (very black &white)
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1. What is contrast? - Desired: 2. What is Gray Scale? - Is it similar or different to contrast? 3. What affects image contrast:
1. Visible difference between light & dark areas (brightness levels) - Low contrast / long scale 2. Total brightness levels visible in image (synonym to contrast) 3. kVp, OID, Grids, Collimation, Filtration, Patient Size, Processing & Post-Processing
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1. What are procedural factors? 2. Low Contrast = _____ Grayscale 3. High Contrast = ______ Grayscale 4. Most important procedural factor that affects image contrast:
1. Any variable that affects amounts of scatter striking IR 2. Long Greyscale (many shades gray) 3. Short Greyscale (few shades gray) 4. kVP
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1. What affects subject contrast? 2. How does kVp effect contrast? 3. What is 15% rule adjust? - How is it increased? - How is exposure maintained?
1. Patient variables that effect absorption - patient size 2. Differential absorption & amount of scatter 3. Adjust contrast using 15% rule - decreasing kvp 15% increases contrast - double or half mAs to compensate
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1. Differential Absorption: FILL BLANKS WITH HIGH OR LOW: A. ______ kvp results in increased attenuation - This creates _______ contrast B. ______ kvp results in decreased attenuation - This creates _______ contrast 2. Scatter Reaching IR: FILL BLANKS WITH MORE OR LESS C. ______ kVp = ______ Scatter Reaching IR = ______ Contrast D. ______ kVp = ______ Scatter Reaching IR = ______ Contrast
1. A. Lower kVp = Higher Contrast (more attenuation & contrast differences) B. Higher kVp = Lower Contrast (less attenuation & less contrast differences) 2. C. Low kVp = Less Scatter = High Image Contrast D. High kVp = More Scatter = Low Image Contrast
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1. How do you increase contrast while maintaining IR exposure? 2. What is OID? 3. What is source of scatter? 4. What is Air-Gap Technique?
1. Decrease kVp 15% & Double mAs 2. Distance between patient & IR 3. Patient 4. Used to improve contrast by reducing amount of scatter reaching IR - used instead of grid to reduce noise/scatter
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1. Relation Between OID & Contrast: 2. How do Grids affect IR exposure? - What is disadvantage of grid? 3. Relation Between Grid & Contrast:
1. Decr. OID = Incr. Scatter (Reaching IR) = Decr. Contrast - Incr. OID = Decr. Scatter = Inc. Contrast 2. Amount of scatter reaching IR - Increased patient dose bc increased technical factors required 3. Higher Ratio Grid = Reduced Scatter (Reaching IR) = Incr. Contrast
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1. Less Collimation = ______ Exposure Field = ______ Contrast 2. Increasing Collimation Results in: 3. _________ - Magnitude of signal difference in remnant beam as result from different absorption characteristic of tissue & structure of anatomy
1. Less = Bigger Field = More Scatter = Decr. Contrast 2. Incr. Collimation = Decr. Exposure Field = Less Scatter = Incr. Contrast * MORE MATTER = MORE SCATTER* 3. Subject Contrast
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1. Filters Function: - Advantage: - Disadvantage: 2. Relation Between Filter & Image Contrast: 3. How do bowel obstructions affect an image? - Type of Disease: - Technique Changes: 4. How does Ascities affect an image? - Type of Disease: - Technique Changes:
1. Absorb low energy photons & allow more penetration of patient anatomy -A: Decr. Pt Dose -D: Decr. Contrast 2. Incr Filter = Decr. Differential Absorption = Decr. Contrast 3. Normal Abdomen = Low Contrast - Bowel Obstr. = Higher Contrast (bc increased gas/air in bowels) - Destructive / Decrease Technique 4. Normal Abdomen = Low Contrast - Ascities = Lower Contrast (bc excessive fluid in abdomen causes more uniform absorption) - Additive / Increase Technique
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1. How does Pnuemonia affect an image? - Type of Disease: - Technique Changes: 2. How does COPD affect an image? - Type of Disease: - Technique Changes: 3. Procedure Factors Effect __________, Which Results in an Effect to __________ 4. Image Contrast Factors Include:
1. Normal Lungs = High Contrast (Full of Air/Low Absorption) - Pnuemo. = Low Image & Subject Contrast (More Attenuated Matter In Place of Air) - Additive / Increase Technq. 2. Normal Lungs = High Contrast (Full of Air/Low Absorption) - COPD = Higher Contrast (More Air in lungs) - Destructive / decrease 3. Affect Scatter Reaching IR = Effect to Contrast 4. kVp OID Grids Collimation Filtration
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1. Subject Variables Effects _______ Which Results in Effects to _________ 2. What Digital Factors Affect Image Contrast? 3. Processing Functions = 4. Post Processing Functions =
1. Differential Absorption = Effect SUBJECT contrast 2. Lookup-Table, Histogram & Windowing 3. LUT & Histogram 4. Windowing (Level & Width)
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1. What is LUT? - How does it work? - What is most important about it? 2. What is Histogram Repersent? - What is most important about it? 3. What is Windowing? 4. Window Level vs Window Width
1. Lookup Table Mathematical process - adjusts pixel values to display contrast & brightness - Ensure correct body part selected for good image quality 2. Exposure/Pixel Values & Frequency - Ensure correct body part for computer to make adjustments 3. Adjust contrast & brightness of digital image 4. Level = Brightness/Luminance - Width = Contrast
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1. Large Widow Width = - Small Window Width = 2. Do Grids Reduce Scatter? 3. Where are Grids located? 4. What are Grids made of?
1. Large = many shades gray (long grayscale) = Low Contrast - Small = Few Shades Gray (Short Grayscale) = High Contrast 2. NO !! They only limit scatter reaching IR 3. Between Patient and IR 4. Lead Strips & aluminum Interspaces between
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1. What is Grid Frequency? 2. What is Grid Ratio? 3. Relation Between Grid Ratio Grid Efficiency: 4. What is a disadvantage of grids?
1. Measure of number of lead strips (grid lines) per unit 2. Efficiency of grid removing scatter - Height of led strips compared to distance between them 3. DIRECT -As Grid Ratio Incr. so does efficiency of grid absorbing scatter 4. Requires increase mAs therefor increased patient dose
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1. What is Grid Conversion Factor? 2. Formula? 3. Ratio/Factors: No Grid = 5:1 = 6:1 = 8:1 = 10:1 = 12:1 = 16:1 =
1. Mathematical way for radiographer to know how much increase or decrease mA depending on grid ratio 2. Original mAs over New mAs = Original Grid Factor over New Grid Factor 3. No Grid = 1 5:1 = 2 6:1 = 3 8:1 = 4 10:1 = 5 12:1 = 5 16:1 = 6
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1.
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1. Types of Grid: (4) 2. What is Grid Cuttoff? 3. Grid Errors
1. Parallel/Non-Focused - Angled/Focused - Moving - Stationary 2. Occurs when useful part of beam is absorbed by the grid due to misuse of grid by radiographer 3. Upside-Down Focus - Off-Focus Grid - Off Level/Angulation - Off Center/Lateral Decentering
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1. Parallel/Non-Focused Grids: - Lead Strips: - Used In: 2. Angled/Focused Grids: - Lead Strips: - Benefit: 3. Moving Grids: - Strips: - Used In: 4. Stationary Grid: - Used In:
1. Parallel - Fluoro or mobile radiography 2. angled to match divergence of beam - more photons to pass through 3. Vibrating during exposure to blur lines - table or wall mounted buckys (needs source electricity) 4. Tabletop or mobile where no connection needed
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1. Upside-Down Grid Error: - Occurs in: - How does it happen? - Results in? 2. Off-Focus Grid Error: - Occurs in: - How does it happen? - Results in? 3. Off-Level Grid Error: - Occurs in: - How does it happen? - Results in? 4. Off-Center Grid Error: - Occurs in: - How does it happen? - Results in?
1. A. Focused grids only B. Grid lines opposite beam divergence C. Loss Exposure along edges 2. A. Using SID outside of range B. Alignment of beam divergence with angled strips C. Loss of Exposure on outside / or one side of image 3. A. Focused or Non-Focused Grids B. Tube / IR Not Aligned - Beam angled against grid C. Loss of exposure across entire image 4. A. Focused Grid B. Beam not aligned to center of focused grid = beam divergence doesnt match angle of lead strips C. Overall loss exposure
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1. What is receptor exposure? 2. What measures this? - What results in a higher measurement? 3. Numbers outside range of above results in:
1. Amount of radiation passing patient and striking IR 2. Exposure Indicator (EI) - More photons passing patient/hitting IR = Higher receptor exposure 3. Over (Saturation) or Under (Quant. Mottle) exposure
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1. What affects receptor exposure? 2. Main controlling factor for receptor exposure: 3. What is distortion? - Types: 4. Causes to distortion:
1. Anything change number of photons reaching IR - mAs, kVp, SID, Collimation, Anode Angle, Filtration, Grid Ratio, Patient Size, Pathology 2. mAs 3. Unwanted misrepresentation of size or shape of anatomy in image - Size (Magnification) & Shape (Elongation/Foreshortening) 4. SID, OID & SOD = Magnification Distortion (Size) - Misalignment or bodypart/CR, tube to IR misalignment and Angling CR = Foreshort/Elongated (Shape)
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1.How does mAs affect IR exposure? - Relation: 2. How does kVp affect IR exposure? - Relation 3. How does SID affect IR exposure? - Relation:
1. mAs controls number of photons in beam and amount reaching IR - Incr mAs = Incr. Beam Intensity (Quantity) = Incr. Receptor Exposure 2. kVp affects Quantity (Exposure) & Quality (penetrating) which affects amount photons reaching IR - Inc. kVp = Incr. Quantity (Exposure) = Incr. Quality (Penetrating) = Incr. IR Exposure 3. Effects because inverse square law, beam divergence affects intensity of photons reaching IR - Short Beam = More intense at IR bc beam less space diverge & Large SID photons are further apart bc more space to diverge - Incr. SID = Decr. Beam Energy = Decr. IR Exposure
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1.How does Collimation affect IR exposure? - Relation: 2. How does Anode Angle affect IR exposure? - Relation 3. How does Filtration affect IR exposure? - Relation:
1. Collimation controls size of FOV / Area being exposed & therefor area for scatter to form - Incr Collimation = Decr. FOV = Decr. IR Exposure 2. Anode Heel Effect (Greater over cathode) - Larger angles decrease exposure b/c more radiation is absorbed by anode & larger angles absorb less of beam - Incr. Anode Angle = Decr. Heel Effect = Incr. IR Exposure 3. Filters reduce low energy photons in primary beam but also remove some high energy photons. More filter means more ability to absorb photons - Incr. Filtration = Decr. Beam Quantity = Decr. IR Exposure
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1.How does Grid Ratio affect IR exposure? - Relation: 2. How does Patient Size affect IR exposure? - Relation 3. How does Pathology affect IR exposure? - Relation:
1. Changes number of photons reaching IR because they absorb photons/scatter - Grids are good for image quality b/c absorb scatter before hitting IR but bad for IR exposure & pt dose - Incr. Grid Ratio = Incr. Scatter Absorption = Decr. IR Exposure 2. Patient size/thickness absorbs or attenuates more or less radiation, which affects amount reaching IR - Incr. Patient Size/Thick = Incr. Absorption = Decr. IR Exposure 3. Pathology affects attenuation, some are additive and some are destructive. Different pathologys change technical factors - Additive Disease = Incr. Attenuation = Decr. IR Exposure
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1. What is Osteoprosis Affect Image? - Type Disease: - Technique Changes: 2. As distortion increases, image quality _______ 3. Size Distortion describes: 4. Three factors contribute to size distortion:
1. Decreases bone density - Destructive - Decr. Technique 2. Decreases 3. Difference between actual size compared to representation in image 4. SID, SOD & OID
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1. What is SID? - How does it affect magnification? - Relation w. Image Quality: 2. What is OID? - How does it affect magnification? - Relation w. Image Quality: 3. What is SOD? - How does it affect magnification? - Relation w. Image Quality: 4. With SID, SOD & OID - what results in best image (desired)
1. Distance from tube to IR - Tube closer to IR increases magnification & further decreases - Incr. SID = Decr. Mag = Incr. Quality of Image 2. Distance between anatomy and IR - Direct relationship - Decr. OID = Decr. Mag = Incr. Quality of Image 3. Distance from tube to object (SID - OID = SOD) - Inverse relationship - Incr. SOD = Decr. Mag = Incr. Image quality 4. Incr. SID - Decr. OID - Incr. SOD = Highest Image Quality
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1. What does magnification factor determine? - Large MF means: 2. Formula? 3. What is shape distortion? 4. What affects shape distortion?
1. Degree of magnification within image from actual anatomical size - Larger image magnification 2. MF = SID divided by SOD * SOD is found by SID - OID * 3. Elongation or shortening of anatomy compared to actual anatomical size 4. Misalignment of X-Ray Tube, Body Part &/or IR
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1. Misalignment of Bodypart & CR - Occurs When: - Results In: - Relation to Image Quality: 2. Misalignment of Tube & IR - Occurs When: - Results In: - Relation to Image Quality: 3. Angling IR to CR - Occurs When: - Results In: - Relation to Image Quality:
1. When long axis of anatomy is angled toward or away from CR - Foreshortening of anatomy - Incr. Angulation = Incr. Foreshortening = Decr. Image Quality 2. Off-centering of CR to IR (between beam divergence & how CR passes edges) - Distorted Anatomy / Elongation - Incr. Angulation = Incr. Elongation = Decr. Image Quality 3. Angulation of tube or IR to CR - Elongation - Incr. Angulation = Incr. Elongation = Decr. Image Quality
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1. If foreshortening is noted on an image, what is most likely cause? 2. If elongation is noted on an image, what is most likely cause? 3. Can elongation be beneficial? why/why not? - Examples:
1. Misalignment of body part & CR 2. Angling CR/IR or Misalignment of tube to IR 3. Yes, with some structures it allows visualization of other structures w/o superimp. - Ex: Pelvis inlet/outlet or Skull Townes
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1. What are Exposure Errors? 2. What are Receptor Errors? 3. What are Processing Errors? 4. What are Positioning Errors? 5. What are Identification Errors?
1. Receptor Exposure & Exposure Index 2. Receptor Damage, Pixel Malfunction & Ghost Images 3. Histograms & Collimation 4. Tube Position, Part Position, Receptor Position & Collimation 5. Incorrect identification on image or Lack of information on image
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1. Receptor Exposure is _______________ - Influenced By: - Underexposure: - Overexposure 2. What is Exposure Indicator? 3. What imaging system does receptor damage occur in?
1. Amount of radiation striking IR - mAs, kVp, Grids, Filtration & Patient Size - Quantum Mottle (pixelated/blotchy image) - Saturation (blacked out / loss of detail) 2. Numeric representation of receptor exposure (indicates under or overexposure) 3. DR or CR receptors
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1. What is Pixel Malfunction? - What does it result in? 2. What is Ghost Image Caused By? - What is result? 3. What is double exposure caused by? - Result In: 4. These are all _________ Errors
1. Dead or damaged pixels (Receptor Error) - Hyper-dense Artifacts (small white spots on IR) 2. Incomplete erasure of CR receptor - Previous latent image still seen on new image 3. Lack of erasure on CR receptor - Previous latent image still seen on new image 4. Exposure Errors
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1. __________ is a graph that tracks exposure values recorded by receptor 2. What is Rescaling? 3. __________ - Mathematical formula adjust original brightness / contrast to desired 4. Why is collimation important when using histograms? 5. These are all _________ Errors
1. Histogram 2. Takes Histogram and modifies (rescales) to what computer thinks should be based on body part 3. Lookup Table 4. Incorrect collimation confuses computer and will try and use un-need areas on histogram instead of ROI only 5. Processing Errors
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1. Incorrect Tube Position Results In: 2. Incorrect Patient Position Results In: 3. Incorrect Receptor Position Results In: 4. These are all _________ errors
1. Shape Distortion (Elongation) & Anatomy projected in wrong area (think of clavicles & apicies) 2. Shape Distortion (Foreshortening) & Cause Superimp. of unwanted places (think clavicles superimp. over spine with rotation) 3. Clipped anatomy or shape distortion 4. Positioning Errors
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1. By Law, Each Image MUST include: (5) 2. Actual Centering of x-ray beam must align within ____ of _______ 3. Actual SID must be within ________ of _______ 4. Light field must align with collimation within _____ of _______
1. Patient Name, DOB, Date of Exam, Location of Exam & Marker 2. 1% of SID 3. +/- 2% of indicated SID 4. +/- 2% of SID
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1. Actual Exposure Time must within _____ of _______ 2. Actual kVp must be within _______ of _______ 3. QA refers/deals with ________ 4. QC refers/deals with ________
1. +/- 5% of indicated exposure time 2. +/- 5% of selected kVp 3. People 4. Equipment
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1. Formula for 15% Rule: 2. Formula for Inverse Square Law: 3. Formula for Direct Square Law: 4. Formula for Magnification Factor:
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1. Formula for Grid Ratio: 2. Grid Ratio Conversion Factors: 3. Formula for Grid Conversion 4. Formula for Grid Frequency:
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1. Formula for Reciprocity Law 2. Absorbed Dose Unit: 3. Formula for Equivalent Dose: 4. Formula for Effective dose:
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1. Formula for Turns Ratio: 2. Formula for Ohms Law: 3. Formula for Voltage: 4. Formula for Current / Amperage:
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1. Formula for Minification Gain: 2. Formula for Total Brightness Gain: 3. Formula for Magnification Gain: 4. Formula for Pixel Size: 5. Formula for Bit Depth:

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