Other imaging modalities Flashcards
(152 cards)
Name 5 advantages of CR/DR
- Greater tolerance
- See wider range of tissues
- Ability to computer-manipulate images
- Space saver
- Cannot lose radiographs
What is the other name for Computed radiography?
Digital radiography
Identify the 2 different types of DR
- Computed Radiography
- Digital Radiography
Is film required in DR + CR?
No
Is this DR or CR?
CR
Name the 4 pieces of equipment used in CR
- Imaging plate
- Cassette
- CR System
- Reader
True or False.
CR be used with + without a Grid
True
What are imaging plates made up of?
Photostimulable phosphor
(A luminescent material that stores X-ray energy and emits light when stimulated by visible light)
What replaced conventional film in CR?
An imaging plate
(IP)
What is an IP stored within?
A Cassette
Where can you place an IP?
Below or Above the table?
Both!
Depends on the practice’s set-up
Within what amount of time must you process an IP in CR?
Within an hour
(ASAP)
How long is the CR process?
1 - 2
minutes
What is an advantage of CR?
It can be viewed + analysed quickly
What should you do to IP daily?
Cleared, as they are very sensitive to scatter radiation!
What is an disadvantage of CR?
Expensive to set-up, intitally for VP
What should you use to clean an IP?
Imaging Plate Cleaner
Explain in 3 steps in basic terms, how CR works?
- During the expossure - the photostimulable phosphor within IP plate stores energy from x-ray photons in a semi-stable (electron trap) creating a latent image
- The cassette is labelled electrionically w/patient details before insserted into reader/digitizer
- IP is rremoved from the cassette automatically by the reader + passes through the rollers
Explain how a CR reader processes the latent x-ray image
- IP plate has photostimulable phosphor which is read by helium-neon laser within the digitizer
- This provides small amount of energy to the electrons in the electron trap
- This allows them to move back to their resting state + therefore release energy in the form of light
- The light produced is collected by a light guide + converted into an AES (Analogue Electrical Signal)
- The AES is amplified by a photomultiplier + digitized by an Analouge converter
- Once the image has recieved the bright light erases the IP + returned to the cassette for re-use
List as many different advantages of CR as possible!
- More sensitive to radiation
- CR plate lowers radiation dose
- Short exposure times
- Reduced saftey area
- Fewer repeat exposuures
- Objects with different thickness on 1 single image
- Faster processing times
- No chemicals are used
- Anaesthetic/sedation time is reduced
- Radiographic study is increased
- Dark rooms are surplus to requirement
- Image quality is greater as no overdevelopment issues
- Images can immediately be reviewed + sent to specialists
- Can be editied or manipulated
- Electronically stored
Give 3 advantages of CR images
- They can be emailed, burnt onto discs + USB sticks
- Can be viewed, edited + manipulated instantly
- Ease of retrieval + storage
Summarise how CR works in 4 basic steps
- Image is stored on radiation sensitive Phosphorous imaging plate
- This is converted into light, through a laser excitation in the CR reader
- This produceds a digital image on a Picture Archiving + Communication System (PACs)
- Can be reviewed + analysed immediately
Is DR expensive to set up?
Yes
Apart from an expensive DR x-ray machine, what else is required for the DR system to work?
An x-ray table