Diagnostic Imaging Flashcards
X Ray
The energy that is produces a radiograph
Radiograph
What we are looking at
Conventional radiograph - what we call an X-ray
Radiologist
Physician
Why does it work
Ionizing radiation delivered to the objects within the path and parameter of the beam
Very harmful - so we have guidelines for how much radiation someone can be exposed to with certain ages
Plain Film
Hard copy
Not as common, but areas that can’t afford digital will still use these hard copies
Film is a piece of acetate held btw two sheets of silver emulsion
Photochemical reaction takes place in the area the radiation beam hits the film
Causes silver to precipitate out and turn the film darker
Computed Radiography
Soft copy
Replaces the need for the photochemical processing that plain film requires
Radiation is absorbed on a phosphor screen which is scanned by a laser
The image is converted into an analog signal which is then processed into a digital image
Digital Radiography
Semiconductor material is used to convert the radiation into an electrical charge
Electrical charge goes through a series of other conversions ending up as a digitized signal
Computed Radiography vs. Digital Radiography
Computed = like hard copy, but you can store the response directly and you can manipulate it to some degree Digital = you can manipulate the input to change your image, has allowed for 3D imaging and CAT scans
Harmful?
Yes… to cells that have high levels of mitosis (bone marrow, testes, ova, intestinal epithelium, epidermis)
Radiodensity
The more dense and object is, the more radiation energy it will absorb
The thicker an object, the more energy will be absorbed
Objects that absorb a lot of energy are said to be radiodense
Objects that absorb less energy are radiolucent
Process of Attenuation
Object will absorb some of the energy, it will reflect that energy, and it will refract that energy
Basically, the idea of how much energy actually gets to the receptor
Air
Radiolucent - Black
Fat
Black/Gray (low radio density - radiolucent)
Water
Gray (low radio density - radiolucent)
Bone
White
Contrast
More radiopaque than bone (white)
Metal
Most radiopaque (white)
CAT scan
computerized image with different slices of the body put together by a computer and it reads the densities and gives you different shades of grey
Contrast
Contrast medium is something that is injected in to the body to allow for a better image to occur
Contrast Media is used to provide an artificial density to tissues
Radiopaque materials = positive contrast
Radiolucent, Air = negative contrast - used in joint imaging
Distortion
How we position - can produce distortions
Imaging Techniques and Analysis
Position = Body part of the patient, what position is it in Projection = From entry to exit of the beam
Viewing Convention
As if patient was facing you
Always view as if the patient is facing you in anatomic position
Radiograph Viewing
Film Markers and Labels
- help with determining the view
Identification Markers
Patient ID
Anatomic Side
Special Markers
Initials of the tech taking the radiograph
Positions
Anatomic position is used as reference point
Ex: Supine, Standing, Weight Bearing
What part of the body is closest to the film
Projection
Name based on the direction the x-ray beam travels
Body part examined is the closest to the film
AP Projection
Anteroposterior
Beam travels in anterior to posterior direction
Film is position on the posterior of the body part
PA Projection
Posteroanterior
Beam travels in a posterior to anterior direction
Film is positioned on the anterior aspect of the body part
Lat
Lateral
Beam moves from the lateral aspect of the body part in a medial direction
At right angles to the AP/PA projection
Can be further named as right or left - named for the side positioned next to the film
Ex: Left lateral - go in from right to left, will image the left better than the right
Oblique
Beam moves through the body at an angle
On a radiograph of the trunk or head, the side is named according to which is positioned closest to the film
Ex: Right oblique - we are imaging out the right side
ABCs
Alignment
Bone Density
Cartilage Space
Soft Tissues
Alignment
Architecture
Contour
Alignment with other bones, normal spacing and spatial relationship
Absent bones, additional bones
Looking at relationship of bones or tissue structures in relation to one another
Always count the bones
Bone Density
General density/quality of the bone Shades of gray Is it what you expect it to be? Textural abnormalities Local density
Cartilage Space
Joint space width
Subchondral bone
Epiphyseal plate
Is it what we expect?
Soft Tissues
Muscles Fat pads and lines Joint capsule Periosteum Other soft tissues
Standard Projections
The routine images that are typically done
Series of guidelines for diagnostic imaging choices
need 2 projections 90 degrees from each other before can diagnose
Standard is an AP and a lateral
Skeletal Pathology
There are characteristic features in many pathological conditions of the musculoskeletal system
Clinical Knowledge - onset, presentation, is needed to increase the accuracy of the interpretation
PTs and Radiographs
We can’t order diagnostic imaging
We can refer to radiologist in most states
If we think someone needs diagnostic imaging, we need to refer them to their physician who can then oder the imaging but we have to be able to back up why we think diagnostic imaging is needed
We look at images ourselves, read the report, should be able to pick up on the larger scale things
Image quality depends on…
Density
Contrast
Detail
Distortion
