T3: Imaging Modalities Flashcards
What is Digital Radiography and what does it involve?
- Uses no films, chemistry or processor
- A single unit which incorporates both camera and processor into one machine
- Consists of a monitor attached to a computer with a special DR plate in same room
- Coversion to DCIM on computer
How do you use DR?
- Warm machine up
- Wait for signal it is ready (green light)
- Patient details are entered into the computer
What are the selections to be entered into the computer when using DR?
- Anatomy
- Projection
- Choose either full or high res field
- Measurements (use callipers first)
What are some benefits of DR?
- Less takes are needed because you can manipulate the image
- Can manipulate contrast and view
What is Computed Radiography and what does it involve?
CR Imaging is done using the original Xray head/generator but using a CR reader and a CR casette and bucky.
The screen stores the energy in proportion to the intensity and when placed in the CR reader, the energy is converted to visible light when scanned by a laser. This is then converted from a raw image into a digital image file.
How do you use CR?
- Place the casette under the buck tray
- Once image is acquired, remove the casette and place into CR reader
What must you NOT do in CR?
DONT DROP THE PLATES
What is fluroscopy and what does it involve?
Fluroscopes perform dynamic studies, helping visualise the motion of fluids and the bodies internal structures in a real time image.
It takes a continuing stream of xray images at a rate of approx 25-30 images per sec. They are then viewed on a monitor with the images being played together.
What can Fluroscopy be used for?
Diagnosing:
- swallowing disorders eg strictures
- collapsing trachea
- motility problems of the stomach and intestines
- flow of blood through abnormal vessells
Orthopedic procedures such as fracture repairs
Contrast studies such as the path of the oesophogous and GIT, contractions of the stomach and intestines and urinary contrast studies.
What is Computed Tomography and what does it involve?
A thin Xray beam rotates around an area of the body, generating a 3D image of the internal structures.
Images are taken in slices.
What is the standard slice scanner used in practices?
16 slices
What are the benefits of an increased slice count?
Offers higher resolution which is useful in cancer diagnosis. Makes it easier to assess the progression of the disease.
What are CTs used for?
Detecting
- tumours
- haemorrhage
- complex fractures
- abdominal disease
- coronary arteries
- spinal lesions
Bone scans
Brain scans
Imaging of the lungs - can detect lung parenchyma
What is Scintigraphy and what does it involve?
A radioactive tracer is injected into animal which distributes around the body and is taken up by areas with increased blood supply and metabolic ativity.
These areas emit Gamma rays detected by a gamma camera, which produces an image of the funcation, shape, size and position ofthe target organ.
Areas of increased bone turn over are shown as hot spots on the images.
What is Scintigraphy used for?
Bone, thyroid and kidney scans
Comonly used in horses to detect injuries such as mulitple limb or shifting limb lameness