Final Review Questions Flashcards
Maximum Permissible Dose
Measures the maximum dose of radiation that a person may be exposed to in a given amount of time.
Badge worn by the radiographer
Dosimeter Badge
6 safety precautions when radiographing a Pt.
Collimation, Lead protective wear, Look away, Avoid retakes, Restraint devices, Decrease time
When using a grid, you must INCREASE the mAs ___ x more
3-4
Absorbed Dose
Gray
Dose Equivalent
Sievert
How do you INCREASE short scale contrast
Change the kVp
Most desirable technique change if the film is doubly dark
Decrease kVp 15%
The films goes ___ the embossing card
Over
To decrease motion on a film
Decrease Time
3 Factors affecting x-ray absorption
Atomic #, Object density, and X-ray energy
2 Factors determining whether x-rays interact with the film or not
Tissue thickness and x-ray energy
Radiopaque
Positive Contrast
3 Negative contrast medias
Air, Co2, and O2
The HIGHER the atomic #
the LESS object penetration
4 Causes of “Fog”
Poor Screen/Film contrast
Focal spot size
Focal Film Distance (FFD)
Motion
Flouroscopy
Live Radiograph, uses x-ray beams
Beam Filters eliminate ___ wavelength rays
Long
Long Scale Contrast
Shades of grey, higher kVp, and body cavity films
Short Scale Contrast
Black/White, lower kVp, and bone films
2 types of film Noise
Mottle and Artifacts
The distance between the x-ray tube and the film
Focal Film Distance
Doubly Dark/Light
Decrease/Increase kVp 15%
Decrease/Increase mAs 50%
1/2 Doubly Dark/Light
Decrease/Increase kVp 10%
Decrease/Increase mAs 30%
1/4 Doubly Dark/Light
Decrease/Increase kVp by 2-3
The final appearance of a radiography based upon it’s density, contrast and detail
Radiographic Quality
Device commonly used when radiographing LA hoofs
Wooden Blocks
Common label used in LA radiographs
Density filter and lead impregnated tape
What % of energy from fast moving electrons is concerted to x-ray energy and heat
1% energy
99% heat
X-rays are generated in the
X-ray tube
The location where electrons collide with the target
Focal Spot
Cathode failure =
filament failure
Driving force behind x-rays
kVp
The number of x-rays produced during exposure
mA
For the best contrast on a film, first change the
kVp
5 tissues that are most susceptible to scatter radiation
Skin and intestinal epithelium, Gonads, Thyroid, Lens of the eye, and blood producing organs
FFD for a Small Portable Machine
26 inches
Developer pH
Alkaline
Fixer pH
Acidic
The action of the developer is to convert ____ silver halide crystal into black metallic silver crystal, while doing nothing to ____ silver halide crystals.
Exposed
Unexposed
Play doh is used in LA to
Pack the sulcus of the hoof and increase detail
One action of the fixer is to stop ___
developing process by removing unexposed crystals.
The minimum amount of time a film needs to be in the fixer in order to adequately remove unexposed crystals
Clearing Time!!!
To make a latent image visible, you have to ___ the film
Develop
Rays that pass through the object and interact with the film
Penetration
Rays enter the object, but don’t exit
Absorption
The rays on either side of the central ray that make up the primary beam
Primary Rays
Lead shutter beam limiting device
Collimator
5 body cavities
Abdomen, Thorax, Pelvis, Spine, and Skull
Dyspnic Pts should not be radiographed in
V/D
How many days into gestation may a fetal skeleton first be viewed
45-50 days
Point of measurement for a lat skull radiograph
Zygomatic Arch
Site of measurement for a cervical spine radiograph
C5-C6
A substance used to increase radiographic contrast within an organ system
Contrast Medium
Any object/agent that is radiopaque shows up what color on a radiograph
Black
2 types of Iodine-Based compounds
Water Soluble
and
Oily Viscous Agent
2 types of Excretory Urography contrast studies
Nephrogram and Pyelogram
An U/S of the Heart
Echocardiogram
what scatters sound in an U/S
Air
2 Types of Positive Contrast
Barium Sulfate (GI tract only) and Iodine Based (outlines hollow organs)
When is a Barium study counterindicated
Suspected perferation
Water soluble Iodine-based contrast study
Conunterindicatied for Mylography
Can use if perferation is suspected
When would you use an Oily Viscous Agent
Lymphography
Radiolucent
Negative contrast
Rostrocaudal positioning is used for what type of skull radiographs
Cranium
An open mouth view is ideal for what type of skull radiographs
Tympanic Bullae
How many views can a complete set of oral films be taken in/what are they
6 views:
Upper/lower- incisors, K-9’s/PM, and Molars.
What is the only things you can adjust on a Dental Unit machine
Time
What are the fixed ranges for kVp and mA on a Dental Unit
kVp- 60-80
mA- 5-10
3 safety rules for dental radiographs
- 6 foot rule (behind machine)
- Dosimeter badge
- Never stand in the direction the cone is pointed
Bisecting Angle Technique
Best view
Determine the plane of the tooth root, the plane of the film, estimate half the distance between these two planes, then position the beam of the x-ray 90 degrees to that point.
Dental Dz shows up as ___ on a radiograph
Radiolucent
5 Cervical spine views
Lat, V/D, Flexed, Extended, and Hyperextended
A non-sequential study includes which radiographs
Survey Film and Zero-Minute Film
A sequential study includes which radiographs
Survey Film, 0 min, 30 min, 60 min, 90 min, etc…(common in GI studies)
Which contrast studies require anesthesia
LGI, Myelography, Vaginography, and Sialography
Positive only contrast studies
Myelography
Negative only contrast studies
Pneumoperitoneography
Barium only contrast studies
Esophagography and UGI
Iodine only contrast studies
Excretory Urography
Sequential studies include
UGI and Excretory Urography
Special procedures that use x-rays
CT scan and Fluoroscopy
Standard view of the Navicular bone
Lat 45 degree DP, Horizontal DP, 65 degree DP cone down, and Skyline
2 methods of 65 degree DP cone down
Upright Pedal- decrease distortion, harder to do.
High Coronary- increased distortion, easy to do.
P3 views
Lat 45 degree DP and Horizontal DP
Indirect digital radiology
most common- uses a Photostimuable Phosphor Plate
Direct digital radiology
Directly converts images to an electrical signal
Higher Frequency U/S probe
Better resolution and detail
Decreased depth
Lower Frequency U/S probe
Less detail
Deeper penetration depth
What color does Fluid show up as on an U/S
Black