Radiology past q Surgery 1 Flashcards
What is the role of intensifying screen?
Convert x-ray into visible light, phospour crystals produce the light
What types of intensifying screens are known?
CaWo4 and rare-earth screens (blue or green)
What are the steps of film processing?
Exposure, developing, stopping the development (rinse or bath), fixation, washing and drying
How does the automatic processor work?
Consists of the following parts:
- Transport System
- Temperature control system
- Recirculation system
- Replenishment system
- Dryer system
- Electrical system
What are the main parts of a conventional x-ray machine?
Control panel, generator, x-ray tube, collimator and cassette
What is the role of the generator?
Generate x-rays. You will find the x-ray tube, which consists of a cathode ray tube of tungsten
producing electrons and an anode, which collects the electrons
What types of generators are used today?
- Single phase with low capacity
- 3-phase which needs 3 phase electric current
- High frequency, largest and most stable capacity
What is the control panel used for?
Adjust the mA (amount of electric current) and kV (electrical difference between the cathode and
anode). Can be analogue or digital
What are the main components of the x-ray tube?
Cathode and anode.
Cathode consists of wire of tungsten producing electrons that travel towards the positive anode.
Anode needs a cooling system (water or oil recirculating)
What is the difference between electron and photon?
Both are elementary particles.
Photon (visible light, packages of energy, quantum of the electromagnetic interaction)
Electron (subatomic particle with negative charge)
What does kV and mAs mean?
Kilovolt = electrical potential unit Milliampere = unit for amount of electrical current (flow of electrical charge through a medium)
Why do we need to use the shortest exposure time possible in radiology?
Minimize the biological tissue damage that it can cause.
Also when taking x-ray pictures of moving parts like thorax, or un-anesthetized animal to minimize
chances of blurry pictures due to movement
How is x-ray beam generated?
By producing electrons at the cathode “ hit positive anode and produce 99% heat and light and 1%
x-ray
How is x-ray beam transformed to x-ray image?
- By sending rays through the object and getting a shadow of this on the film
- Due to different absorbencies of tissues different parts will be more or less dense
- X-ray beam, which is let out from the window of the tube will hit the cassette or image receptors
- Intensifying screen found in the casette convert x-ray beams into visible light
What is the principle of digital radiography?
Principle: beams onto a cassette and then:
Indirect: cassette is placed into a reader, which is connected to the monitor. There is no
conventional film used but a phosphor plate, which stores the energy of the photons, computer reads
the information on the phosphor plate and we can see the picture on the computer.
Direct: monitor is directly connected to a flat panel sensor/cassette in the x-ray table. We can
see the image directly within seconds
What is the principle of conventional film processing?
Need to process the film to visualize. In conventional radiography the photochemical change is used
How does fluoroscopy work?
Same x-ray tube is used but a different image receptor. Fluoroscopy: instead of a normal film you
use a fluorescent screen or intensifying image. Not used in veterinary medicine since the animals
move too much
What does the visible light and the x-ray beam cause on x-ray film?
Exposure to visible light or incorrect safe light in dark room produced fog on the developed film. The
film gets black. Used properly, x-rays will produce a pattern of varying depths of blackness on the
film
What does an x-ray cassette consist of?
Grid, x-ray film, sponge and intensifying screen (plastic base glued to the cassette, reflective layer,
fluorescent layer and protective layer)
What is the role of intensifying screen?
Since the film is more sensitive to light than to x-ray, the intensifying screen is used to convert x-ray
into visible light. Screen consists of phosphor crystals that produce the light. Also the intensifying
screen allows a reduction of the exposure values
What is grid and when do we use it?
Used to increase the quality of the picture when an object is over 10
cm and reduce the exposure
How does the x-ray film automatic processor work?
Device designed to move medical x-ray films from one solution to the next, in the film developing
process, without the need for human intervention except to insert a film or cassette
How many people are needed for radiography of a horse?
3 (one holding the horse, one the cassette and one managing the machine)
Where do bone tumors usually occur?
Near stifle or elbow far
Which one is not a lung pattern?
Fibrous, (alveolar, interstitial, nodular, bronchial, mixed, bullous)
What does the vertebral heart scale inform about?
Size of heart
When do we sedate horses for X-ray?
Always
How to prepare a horse for radiographic interpretation?
Preparations of the patient, sedation, remove shoes, remove mud and loosen horny tissue and trim
the frog
Which radiologic signs are not characteristic for hypertrophic Osteodystrophy?
The characteristic signs are: early phase -> “second physical line”, sclerosis at metaphysis;
advanced phase -> “cuff formation” at the metaphysis of long bones; late complication ->
antebrachial malformation
What contrast media is used for double contrast of bladder?
Air and Iodine
What is not a part of the digital radiography?
Intensifying screen (Form part of it: x-ray tube, collimator, grid)
Which statement is not true?
In a healthy dog you can see the cartilage, (only subchondral bone)
When can HD be seen on the x-ray?
After 6 months
6. month: 16% 12. month: 69% 18. month: 83% 24. month: 96%
If you see decreased radiopacity of the femoral head and neck on an x-ray of a
Spitz dog, what do you expect?
Perthes’ disease
When can you see the fetal skeleton on the x-ray?
After 45th day
When do you earliest x-ray a dog with ileus fed with contrast medium?
12 hours?
Who is often affected by tracheal collapse?
English bulldog
What is the principle of ALARA?
To keep the radiation As Low As Reasonably Achievable
When can an osteophyte be detected?
After 3 weeks
Which part of the carpus is the most affected in OCD?
The cartilage
Hansen I, can also be described as?
An extrusion
Hansen II, can also be described as?
A protrusion