Radiography Flashcards
1
Q
What are the 5 basic radiograph densities from decreasing order
A
- Gas
- Fat
- Fluid/Soft Tissue
- Bone
- Metal
2
Q
List some Abnormal Border Effacement examples
A
3
Q
- What must all radiographs legally have on them?
- What does this include?
- When does it have to be put on the radiograph?
- What types are there?
- What else is required on x-rays?
- If putting in for a scheme what else is required?
A
- ID label
- Clinics Name, Date, Patients Name and Number, Owners Name
- At time of exposure or before processing
- Lead Number types, Radiopaque Tape, Light Flasher systems, Digital
- Must also have Left/Right Markers
- Microchip / Tattoo
- Pedigree Name
4
Q
- What happens to Developer Solution as time passes?
- How often should the Developer Solution be changed?
A
- Time (oxidation) plus usage (Liberation H+) –> Decreased activity –> Decreased speed of film and decreased contrast of the image.
- Solution should be changed every 4 to 6 weeks Dependant on usage.
5
Q
A
6
Q
What happens if the temperature of the Developer Solution is:-
- Below 16 Degrees
- Above 25 Degrees?
A
- Too low <16C - Activity too low, underdevelopment regardless of time
- Too Hot >25C - Developer Fog, Emulsion damage
7
Q
Pre Exposure Button
Explain Step One of Xray Production
A
Press the Pre-Exposure, activates the current through the filimant, heating the atoms in the wire, giving energy to the atoms which shoot out to make an electron cloud. Cloud size depends on the mA. The focusing cup charges giving it a negative charege so the cloud doesnt disperse.
Misuse will cause Cathode Damage getting thinner and breaks.
8
Q
How do we get depth perception with Radiographs?
A
Always take a minimum of 2 radiographs (Orthogonal Views) 90 degrees to each other.
9
Q
What are some factors which affect radiographic detail
A
- Tissue composition
- Contrast
- Radiographic Density
- Scatter radiation
- Screen Film Combinations
- Motion
- Processing
- Radiographic Technique
10
Q
Scatter radiation in the x-ray room would be most significant for which of the following procedures. (1.5 marks)
Select one:
a. a ventrodorsal view of the pelvis of a dog.
b. a thorax radiograph of a cat.
c. a lateral radiograph of the shoulder region of a horse.
d. a lateral radiograph of the fetlock region of a horse.
e. radiograph using a high mAs and low kV technique of any anatomy
A
c. a lateral radiograph of the shoulder region of a horse.
11
Q
Explain the difference between Digital Radiography (DR)
Indirect Detection Vs Direct Detection
A
Indirect Detection - Flat panel detectors
Utilizes a screen
○ Interacts with x-rays to produce light
○ Rows and columns of detector elements
(replace analog film)
Flat panel detects light produced (indirect
detection) for image formation
○ Light creates a charge build up in each element
○ Each element is individually read out
○ Read out is in the form of an electronic signal
Direct Detection - Flat panel detectors
One less step in image formation
○ Light is not produced
○ Electrons released after x-ray strikes a
photoconductor (Selenium)
○ Electrons collected by detector elements
Image formation
○ Charge collected by each element
Read out similar to an indirect panel
12
Q
What is a Latent Image and how is it created?
A
13
Q
What are the different types of Detectors?
Where and how are these Detectors worn?
A
- Film Badges
- Plastic with filters and xray sensitive film
- Thermoluminescent Dosimetry
- Absorbs energy of exposure and stores
- released as light on heating
- more sensitive than film badges 0.1mSv
- Luxel Badges / Optically Stimulated Luminescence (OSL)
- Aliminum Oxide Film
- Stores Dose - Emssions released by laser beam
- Records 0.01 mSv
- Worn at waist or Chest hight, Correct side to be facing forwards, worn below lead aprons, changed regularly, reports kept and available.
14
Q
What is Beam Filtration?
How much does it Filter?
What is the legal requirement?
A
- It is a piece of aliminium that is placed in the beam to absorb low energy xrays, this increases the average beam energy to the patient.
- 3mm Aliminium Reduces patient dose bu up to 80%
- 2.5mm Aliminium for >70kV
15
Q
Which of the following is the most accurate method of monitoring personal radiation dose?
Select one:
a. Wearing a film badge.
b. Using sonar pulsation dosimetry devices.
c. Using a thermoluminescence dosimeter.
d. Using a Laser Luminescence dosimeter.
e. Using an optically stimulated luminescence dosimeter.
A
e. Using an optically stimulated luminescence dosimeter.
16
Q
Explain FFD and OFD
A
17
Q
- If I have radiographic film that has opaque and milky areas after post processingwhat may have happened?
- What would happen to this film over time?
A
- Poor Fixing
- It will discolour to brown
18
Q
What are the 3 Digital Imaging Networking and Display systems required in a practice?
A
- Picture Archiving and Communications System (PACS) - Storage and transfer.
- Medical Information Systems
- Hospital Information System (HIS) - Patient Info, Billing
- Radiology Information Systems (RIS) - Ordering rediographs (or Ultrasound, MRI, CT etc), Imaging Reports
19
Q
X-Ray production Step 2b
A
20
Q
What is Screen Speed?
If I wanted a High Definition xray would screen speed would I use?
A
21
Q
What are teh four phases of Film Processing?
A
- Developing
- Fixing
- Washing
- Drying
22
Q
What computer manipulations can you do with post processing? And what does it mean?
A
- Window
- How many shades of grey
- Level
- The central value for the shades of grey
- Pan
- Moving the image
- Magnify
- **Reversible alterations to the image.
23
Q
What is Film Latitude?
What is the relation between wide latitude and High Contrast?
A
24
Q
If I want a good detail radiograph what film speed do I use and why?
What is the rule for thin body parts regarding film speed?
A
Slow Film speed as it has smaller crystels so detail is better however it needs higher exposure to get good radiographic density.
Slow film speed for thin body parts, however when tissue thickness becomes too great and it is necessary to use a grid a faster screen is used to reduce exposure to personal
25
How do you tell if a dribble mark is from poor washing or poor Drying on your Developed Radiograph?
Drying marks are colourless where washing marks are yellow
26
What is the Code of Practice relevant for Veterinary medicine regarding Radiation Safety?
* Radiation Protection Series Publication no. 17
* Code of Practice and Safety guide for radiation Protection in Veterinary Medicine 2009
27
What is the purpose of wearing gloves while taking a radiograph?
To protect the wearer from scatter radiation, ands with gloves on should still not be in the primary beam. Gloves must be worn within 1m of the primary beam.
No Hands gloved or otherwise should be in the primary beam.
28
Select the following result on magnification, if the object-film distance is
decreased.
• Select one:
a. Increase
b. Stay the same
c. Change only if the focal spot has been changed
d. Decrease
Decrease
29
1. Poor Radiographic Density has 2 differentials what are they?
2. How do you differentiate between the two
1. Underexposed and UnderDeveloped
2. If anatomy is not seen that is underexposed
30
31
What is Border Effacement?
Give some normal examples of this
* Silhouette Sign (Masking)
* Dont confuse with (Summation)
* Structures of the same opacity are in physical contact
* Loss of individual margins
* structures merge and appear as one
* Normal Examples
* Liver and Diaphragm
* Bladder and urine
* Coronary vessels, myocardum and chamber lumen
32
What are some signs of poor radiographic density?
The Background should be Black if its grey its poor.
If you can see your fingers through the black its Poor
If the image area is too pale this is also poor density
33
If I have anatomy clipping what has happened and what system have I used?
Over Exposed with Digital Imaging
34
If the radiograph looks very grainy (white spots all over what could this be?
Old Intensifying Screen, needs replacing
35
* What does the Fixer do?
36
What is the structure of Film?
How do Film types vary?
Silver Halide crystals within emulsion (AgBr)
Single vs Double
Speed
Detail
Contrast and Latitude
37
The Protective CLothing needs to have lead inside it. What thickness does the lead need to be?
0. 25 mm \<100kV
0. 5 mm \>100kV
38
1. What temperature do we have the developer solution at?
2. A rapid density and contrast change can be seen up to how long after film is in the solution?
3. What happens if we go over this time?
1. at 20 Degrees C
2. Up to 3 mins
3. Decrease contrast \> 3mins = Developer Fog (When unexposed AgBr --\> Silver)
39
When doing an exposure chart what is the order that we do the calculations?
5steps
a) tissue type
b) tissue thickness
c) desired contrast
d) grid use and the exposure calculation for its use
e) mA and time calculations and the explanation for the choice of the actual mA and times chosen.
40
An increase in the mA setting will alter the primary x-ray beam, patient
interactions and the final image appearance.
b) What effect will an increase in mA have on the final image appearance.
(1 mark). There is more than one correct answer and marks will be removed for incorrect answers.
Select one or more: (50% for each correct answer, 50% reduced for each
incorrect answer)
a. a decrease in motion artefact
b. there will be no change in the image density
c. a decrease in the image contrast
d. an increase in the image density
e. No effect on the image contrast
f. an increase in motion artefact
g. the image density will be more even across the film with large field sizes
h. an increase in the image contrast
d. an increase in the image density
e. No effect on the image contrast
41
1. What do imaging receptors include?
2. What are the 2 types of processing?
* Xray film and intensifying screens
* Computer Radiography
* Digital Radiography
1. Digital Processing
* Preprocessing
* Post Processing
* Film Processing
42
How do we tell an underdeveloped film from an underexposed one?
If the background denmsity is uneven AND we can see Atomic Structure the film is underdeveloped.
43
What is a MACH line?
What does it get confused with alot?
MACH EFFECT
• Optical illusion
• Lateral inhibition
• Regions of differing contrast result in suppression of function within adjacent regions of the retina
• Perceived but do not exist
• Positive (white) or negative (black) bands
• 2 structures are superimposed create an imaginary line at the division between the 2
structures.
• Proximal metacarpals - overlapping bone margins.
• Rectum filled with faeces overlapping the pubis.
• Often mistaken for fractures.
• A radiolucent halo surrounding the heart when marked opacity within the lungs
44
What is the major difference between Computed Radiography (CR) and Digital Radiography (DR)
45
Why is Central Ray positioning important and in what instances is it very important?
46
What are some storage and handling film artefacts?
## Footnote
**Storage**
Cool, dry, low humidity conditions.
Upright not flat.
Light tight box or hopper
Expiry dates check.
**Handling**
Gentle, do not bend or apply too much finger pressure, hold edge.
**Correct safelights**
Type, time exposed, cracks in filters.
**Other**
Darkroom light leakage cassettes not sealing.
47
What are Stochastic and Deterministic effects of Radiation?
* Deterministic Effects: Effects that occourt due to dose of Radiation
* Once a threshold has been reached the effect is likey to occur
* Severity is dose related
* Stochastic Effects: Probability effects
* Increased dose will cause increased chance of disease
* Severity is not dose related
48
With this Film Charateristic Curve what does a step increase between C and D mean?
Slope = Contrast
A steep slope = High Contrast
49
Which of the following technologies has
the highest (best) spatial resolution?
Select one:
a. Analog radiography
b. Direct digital radiography
c. Indirect digital radiography
d. Computed radiography
Analog radiography
50
51
* When do you need to use a grid, what is the general rule?
* What ratio grid do I use for a \<90kV
* What Ratio do I use for a \>90kV
* Dense material eg Bone \>9cm, to 15cm with a thorax.
* General rule is add a grid at 10cm
* 8:1 \<90kV
* 12:1 \>90kV
52
What 3 things can cause High peripheral film density?
* Over Development
* Over Exposure with high amount of Peripheral scatter
* Light Fogging
53
What is Image defination and detail (Edge Sharpness) affected by?
What can these lead to?
Screens
Film
Motion
Focal Spot Size
Also depentent on geometric factors.
* Lead to Errors or misinterpretations
54
What are the 2 basic ways a Screen Artifact is produced? How do we fix these?
1. Objects between the intensifying screen and film - (Block the light leaving a white shadow), From Dust, hair between the film and screen
* Resolution - Clean Screens
2. Damaged of old phosphors - no longer flouresce or produce light. Multiple small white dots spread throughout the image and film background.
* Resolution - Replace screens
55
What does a developer Solution Contain?
Reducing Agent
Soultion is always Alkaline
56
57
1. Absorbtion and conversion of the xray energy by the screen is affected by?
2. Explain these
1. Screen Phosphor type and Screen Properties (Construction)
2.
58
What is Radiation Absorption and how is it measured (what Units)
What was the old unit of measurement and what does that = to the new units of measurement
* Absorbed dose is the amount of energy that has been absorbed by the tissue
* The unit for absorbed dose = The Gray (Gy)
* 1Gy = 1Joule/kg of tissue
* The old and obsolete unit was Rad
* 1 Gy = 100Rads
59
Label these regarding Contrast
1. Film density too high so cannot accurately assess contrast, Poor contrast
2. High Contrast
3. Medium Low contrast
60
With digital what are the principal differences relating to image control?
* Objective Assessment
* Exposure Indices within correct range
* Subjective
* Double the image size
* No pixilation
* Multiple dots = underexposure
* Evaluate for anatomic clipping = overexposure (too hight technique)
61
What are the 2 parts of the Fixing Times?
How long do we keep the film in the Fixer?
Fixing Times
Clearing Time –
time to visibly clear (approx 1 min).
Transforms from a milky opaque appearance to clear transparent appearance.
Undeveloped silver halide (AgBr) is dissolved within the emulsion.
Fixing Time –
time to completely dissolve all AgBr
and for all dissolved complexes to diffuse out of the emulsion
AND to harden the emulsion.
Fixing time is normally twice the clearing time.
Time in Fixer often 2 x development time or 5-10 mins
62
What is an intensifying Screen and how do they work?
They are the white foam pads inside the cassette
63
* What is the Annual Dose Limit (ADL) for for ionizing radiation?
* What is the Dose Limit for Pregnant workers?
* What is the General Public Limit?
* Occupationaly Whole Body Dose Limits
* The effective dose limit is 20mSv/year, averaged over 5 consecutive calendar years.
* No more than 50mSv in any one year
* Pregnant radiation workers - the monthly exposure limit to the foetus should not exceed 0.5 mSv
* The effective dose limit for the general public is 1mSv/year
64
* Having a CT how much more radiation absorbtion would I get compared to a normal xray?
* How much radiation Absorbtion would a male require to become :-
* Temporarly sterile
* Permanently Sterile
Abdominal CT = 10mGy (40 times more than xRay)
Stomach abdomical radiograph = 0.25mGy
* 150mGy in a single dose (7 x ADL)
* 400mGy over a year (20 x ADL)
In females its from 350-600mGy (15-30 x ADL) in a single dose or 200mGy (10 x ADL) per year from a prolonged dose
65
Select the one correct answer. The most effective method of controlling scatter production in radiography is to
Select one: (1.5 marks)
a. Decrease the tissue thickness via compression techniques.
b. not straddle the beam
c. Prevent backscatter by using lead backed cassettes
d. Reduce the kV
e. Reduce the energy of the scatter radiation
f. Collimate the beam to the smallest possible area of interest
g. Use an increased object film distance
h. Use a focused grid correctly
f. Collimate the beam to the smallest possible area of interest
66
Edge Sharpness is affected by
* Geometric Unsharpness
* FFD, OFD, Foacl Spot Size, Film Screen contact
* Motion Unsharpness
* Inherent Unsharpness (Film Speed related)
* Quantum Mottle
* Distortion (Angled Femur Poorly Positioned)
67
Explain the Cathode and Anode of the X-Ray Tube
* **Cathode**
* Coiled filament wire and focusing cup
* Low voltage circuit and Negative electrode
* Small and Large focus (wires)
* **Anode**
* Target and focal spot
* High Voltage circuit and Positive electrode
* Stationary and Rotating types
68
* What does A.L.A.R.A principle stand for?
* Xrays are Ionizing radiation what does this mean?
* As Low As Reasonable Achievable
* Atomic interations cause excitation of electrons and energy deposition into tissue
69
Looking at a film speed curve how do we know which one is faster?
70
Name the Componants of an X-Ray Machine
71
Regarding X-Ray Production what does mA control?
mA controls cloud size
72
What are the Biological effects of radiation?
* Cell Damage
* that stops a cell reproducing
* that mutates a cell
* Somatic or Genetic Effects Seen
* Somatic = Exposed Person
* Genetic = Hereditary (Descendants)
73
Describe what the washing phase does.
How is the best way to do it?
What results does poor washing have?
**Poor Fixing or Underfixed**
Unexposed AgBr complexes remain in the emulsion
and react with light and over time
a discolouration superimposes over the film and darkens the image obscuring the anatomy, periphery and background.
Severe underfixing - not cleared - milky or opaqu after processing.
Moderate to mild underfixing
Initially normal in appearance
After Time - films discolour [pink to brown] on storage and pale areas darken.
Uniform pink brown (or yellow) artefact superimposes over the entire film and darkens the image.
Not Hardened – film surface damaged scratches and emulsion marks when wet.
74
When looking at a Film Contrast slope graph is a steep slope related to a High or Low Contrast?
75
1. What makes up 75-90% of the Primary x-ray beam?
2. What makes uo 10-25% of the Primary x-ray beam?
Heat Production (99%) – outer shell
electrons
○ Limiting the capacity to produce high
exposures.
Radiation Production (1%)
○ Radiation makes up the primary x-ray beam
1. Bremsstrahlung Radiation (BR) (75 – 90%) – nucleus
2. Characteristic Radiation (CR) (10-25%) – Inner shell
electrons
76
What causes the error here?
Poor Film Screen Contact.
See the blurring on the one side along the vertibrae (right side)
77
How do we determine if its grid cut off through incorrect focal distance for the grid
You will have abnormal grid lines of varying thickness along the edge of the background. THey are not apparent in the centre of the image however.
78
Where are Radiation Safety Rules and Regs from?
* International Commission on Radiological Protection (ICRP)
* Australian Radiation Protection and Nuclear Safety Agency (ARPANSA)
* Radiation Health and Safety Advisory Council - Legislation
* Radiation Protection Standards, Codes of Practice and Recommendations
79
What are some Benefits of Digital Imaging?
Benefits of Digital Imaging
Image distribution
Film storage
Improved radiographic appearance
More flexible with over/under exposure
Image processing
Pre- versus post-processing
○ » Filters
○ » Contrast
More rapid image production
Dispense with wet processing
80
What are the 2 basic categories of Contrasts and give examples of these
* Positive Contrast
* Barium
* Iodine
* Negative Contrast
* Gases
81
When you press the Exposure button explain the X-Ray Production
82
What is the unit for Radiation Dose Equivalent?
What is the old unit of measure?
What is the conversion of New to old unit?
What is the Effective Radiation Dose measured in?
Sievert (Sv)
Old Unit = rem
1Sv = 100rem
Sievert Sv
83
Picture on the right what is the wrong with it if this is for a Digital image?
If its for a Analogue Image?
* Digital grainy appearance is underexposed
* Analogue grainy appearance is Old Screen you need to replace it
84
What does Poor Fixing or Underfixed look like?
**Poor Fixing or Underfixed**
Unexposed AgBr complexes remain in the emulsion
and react with light and over time
a discolouration superimposes over the film and darkens the image obscuring the anatomy, periphery and background.
Severe underfixing - not cleared - milky or opaque after processing.
Moderate to mild underfixing
Initially normal in appearance
After Time - films discolour [pink to brown] on storage and pale areas darken.
Uniform pink brown (or yellow) artefact superimposes over the entire film and darkens the image.
Not Hardened – film surface damaged scratches and emulsion marks when wet.
85
What is Bremsstrahlung Radiation (BR)
86
What is Summation
When parts of the patient in different planes (not in contact with each other) are superimposed
* Opacities are added
* Film Density = sum of all superimposed structures at that point
* Swiss Cheese analogy
* Sometimes Summation opacities can be mistaken for pathology
* Trace the margins to differentiate between an abnormal structure or a summation shadow
87
1. Why does the Developer Solution become inactivated with time and Use?
2. Your final developed image can be impacted by what 4 influences?
* Liberation of H+ -becomes acidic and inactive with use.
* Oxidation of solutions with time.
* Inactivation of reducing agents with use.
2. Development process is influenced by:
1. Time in developer
2. Temperature of developer
3. Age of the developer solution
4. Inactivation of the developer solution
88
How can we tell if our film has been over or under developed?
89
What does DICOM stand for?
What are they used for?
What Extension do they have.
What is the advantage and disadvantage of converting these images?
1. Digital Imaging and Communications in Medicine
2. Diagnostic Image file format, requires specialized software, Enables easy :- retrieval, Viewing, Transmission, Secure Patient Information
3. DCM
4. When converted to JPG these files are very small But no longer diagnostic
90
What are the Radiation Safety Principles?
* Time, Distance and Shielding.
* Time - Reduce time exposed to radiation
* Limit retakes
* Use a Technique chart
* Use Adequate Restraint
* Distance - Increase your distance from the Primary Beam
* Inverse Square Law, If you double your distance you reduce your exposure by 4
* Shielding - Protective Clothing
* Lead Gowns
* Thryoid Protectors
* Lead Gloves
* Lead Screens
* Screens
91
1. What 2 major problems in radiography does Scatter create?
2. What methods can be used to reduce the effects of Scatter Radiation
* Poor detail within the image
* Radiation Safety Hazard outside the image
1. Lead Gloves and Aprons to protect people in the room.
* Distancing yourself from the beam.
* Never Hold Casssette in your hands
* Coning the beam to always be inside the edge of the cassette
* Use of Grids - Improves detail by reducing scatter hitting the film
