PowerPoint Two Flashcards
Medial rotation
A rotation or turning of a body part with movement of the anterior aspect of the part toward the inside, or median plane
Lateral rotation
A rotation or turning of a body part with movement of the anterior aspect of the part toward the outside, or away from the median plane
Abduct or abduction
Movement of a part away from the central axis of the body or body part
Adduct or adduction
Movement of a part toward the central axis of the body or body part
Pronate/pronation
rotation of the forearm so that the palm is down.
Supinate/supination
rotation of the forearm so that the palm is up (in the anatomic position)
Protraction
movement forward from a normal position. For example: the mandible.
Retraction
movement backward or the condition of being drawn back. For example: the mandible.
Elevation
Lifting, raising, or moving of a part superiorly
Depression
letting down or lowering or moving of a part inferiorly
Circumduction
Circular movement of a limb.
Radiographic Criteria
The definable standard that radiographs are evaluated by.
Radiographic criteria format
Structures shown, positioning, collimation and CR, exposure criteria and image markers.
“Stuctures shown” from Radiographic Criteria
The anatomic parts and structures visualized on a radiograph
“Postitioning” from Radiographic Criteria
Placement of body part in relationship to IR
and positioning factors important for projection.
“Collimation and CR” from Radiographic Criteria
Decribes how collimation borders should be seen
Location of CR
Center of collimation
“Exposure criteria” from Radiographic Criteria
Describes how technique can be evaluated for optimum exposure of body part
Motion
“Image Markers,” from Radiographic Criteria
Patient side markers (R or L) Time markers (as needed)
Essential IR markers
Anatomic side markers (R or L) and patient ID marker.
Basic (routine) projections
Commonly performed projections taken in US and Canada on all average patients who can cooperate fully
Actual routines vary depending on radiologist’s preference and imaging department
Special (Alternative) projections
Sometimes taken in addition to basic projections
Are those projections most commonly taken to better demonstrate specific anatomic parts or certain pathologic conditions
Two positioning rules or principles
Minimum of two projections
Anatomic structures superimposed
Localization of lesions or foreign bodies
Determination of alignment of fractures
Second postioning rule
Minimum of three projections when joints are in prime interest area
AP or PA
Lateral
Oblique
Examples of exams needing three projections as basic:
Fingers Toes Hand Wrist Elbow Ankle Foot Knee
Long bones require two projections as basic. Examples are:
Forearm Humerus Femur Hips Tibia-fibula Chest
Exceptions to positioning rules are:
Post reduction upper and lower limbs
Pelvis study projection unless a hip injury is suspected.
Abdomen (KUB)
Define palpation:
Refers to process of applying light pressure with fingertips directly on patient to locate landmarks.
How is palpation done?
Gently, patient must be informed of the purpose of it, and permission must be acquired.
How are radiographic imaged viewed?
Whichever way the radiologist chooses, however they are usually viewed with the patient in the anatomic position.
How is an AP chest projection viewed?
With the patient in the anatomic position.
How is a PA chest projection viewed?
With the patient in the anatomic position.
How’s re lateral projections viewed?
By the side closest to the IR.
How are AP and PA oblique projections viewed?
With the patient in the anatomical position.
How are decubitus chest and abdomen projections viewed?
From the “viewpoint” of the X-ray tube.
How are projections of upper and lower limbs viewed?
From the “viewpoint” of the X-ray tube; if there are digits, they are placed up. If no digits are shown, then it’s viewed in the anatomical position.
How are MRI and CT’s viewed?
Axial projections are generally viewed with the patient’s right on the viewer’s left.
Describe exposure factors (technique).
Radiographer sets three exposure variables or factors on the control panel of the x-ray machine each time a radiographic image is produced. These factors are sometimes referred to as “exposure” or “technique factors.”
The three technique factors are:
- Kilovoltage (kV)
- Milliamperage (mA)
- Exposure time (seconds)
Describe milliamperage seconds (mAs)
Milliamperage (mA) and time (s) are usually combined into milliamperage seconds (mAs), which determine the quantity or amount of x-rays emitted from the x-ray tube each time n exposure is made. Milliamperage determines the amount of blackness or density.
What are the rules for changing the density?
When film images are underexposed or over exposed, a genera rule states that a minimum change in mAs of 25% to 30% is required to make a visible difference. A greater change may be required, frequently 50% to 100%.
Automatic exposure control (AEC):
A system that provides automatic termination of exposure time when sufficient exposure is received by the selected ionization chamber cell.
Contrast:
the difference in density on adjacent areas of a radiographic image. The greater the difference, the higher the contrast.
What is the primary controlling factor for contrast?
Kilovolts. Kv controls the energy or penetrating power of the primary x-ray beam.
Example technique showing short scale, high contrast (for chest).
50kV(800 mAs). Very black and white.
Example technique showing long scale, low contrast (for chest).
110 kV(20mAs). Many shades of grey.
