Positioning 1- Chapter 1 Flashcards
What are the four types of image receptors?
- Cassette with film
- photostimulable storage phosphor image plate(PSP IP)
- solid-state digital detectors
- Portable digital radiography
- Fluoroscopic image receptor
What is DR or DDR?
Direct digital radiography
Digital radiography
What is CR?
Computed Radiography
What is special resolution and what is it controlled by?
•ability to visualize small structures Previously termed recorded detail Controlled by •IP phosphor (digital) •DEL size (digital) •Geometry •Distance •Focal spot size •Motion •Film •Intensifying screen
What is distortion and what is it controlled by?
Misrepresentation of the size or shape of a structure
Shape distortion, elongation or foreshortening, controlled by
•Alignment
•Central Ray
•Anatomic part
•Image receptor (IR)
•Angulation
Magnification is size distortion Present in all images Controlled by •Object-image receptor distance (OID) Generally as close as possible •Source-image receptor distance (SID) Generally 40" or 72"
What are the three types of motion?
- involuntary
- voluntary
- equipment
Which of the quality factors is defined as the overall blackness (or brightness, in digital) of an image?
A. Contrast
B. Density
C. Distortion
D. Spatial resolution
B. Density
Which image quality factor allows the distinction between adjacent structures and tissues?
A. Contrast resolution
B. Brightness
C. Distortion
D. Special resolution
A. Contrast resolution
For lateral projections of the head and trunk (head,spine,chest, abdomen, and pelvis) where do you place markers?
Always mark the side closest rival to IR. If the left side is closest, use the L marker. The marker is typically placed anterior to the anatomy.
For oblique projections that include R and L sides of the body (spine, chest, and abdomen), where is marker placed?
The ide down, or nearest IR, is typically marked. For a right posterior oblique (RPO) position, mark R side
For limb projections, what markers should be used?
Use appropriate R or L marker. The marker must be placed within the edge of the collimating x-Ray beam.
All of the following are examples of involuntary motion, except:
A. Peristalsis
B. Heartbeat
C. Breathing
D. Chills
C. Breathing
How do radiographer a help reduce the risk of imaging involuntary motion?
A. Use immobilization
B. Appropriate patient instructions
C. Clear Communications
D. Use the shortest possible exposure time
D. Use the shortest possible exposure time
All of the following are required ID on a radiographic image, except the:
A. Side marker
B. Patient name or ID number
C. Referring physician’s name
D. Name of the facility
C. Referring physician’s name
What are the common distances used in SID?
40 inches (102cm) traditionally used on most exams
72 inches(183cm) used on exams with increased OID to reduce magnification
48 inches (122cm) is recent increase in many facilities
How many cm is 40 inches?
102cm
How many cm is 48 inches?
122 cm
How many cm is 72 inches?
183 cm
How many inches is 102 cm
40 inches
How many inches is 122 cm
48 inches
How many inches is 183 cm?
72 inches
A technique chart must include all of the following, except
A. Pathology type
B. kVp
C. AEC
D. Grid
A. Pathology type
Which guideline is used to local the pubic symphysis on an obese patient who is approximately 5 feet, 5 inches?
A. 15 inches from jugular notch
B. 21 inches from the jugular notch
C. 22 inches from the jugular notch
D. 24 inches from the jugular notch
C. 22 inches from the jugular notch
How do you find the pubic symphysis on an obese patient?
• Locate the jugular notch
pubic symphysis can be located by using these measurements from the jugular notch.
• 6 feet: 24 inches
WHAT IS AN IMAGE RECEPTOR?
The device that receives the energy of the x-ray beam and forms the image of the body part
Define Optical Density (OD)
Optical density is defined as the degree of blackening when associated with radiographic film and as brightness when appearance on a digital display is described.
Define brightness
Balance of light and dark shades in a displayed image
Define contrast
Contrast is the relative difference of intensities in two adjacent regions of an image.
Define special resolution
The ability to visualize small structures
Define magnification
Enlargement of an area.
Increases with increased OID and decreased SID
Define optical density(OD)
Degree of blackening(film)
Brightness(digital)
Define brightness
Digital imaging term equivalent to OD
Define contrast
The difference in density of any two areas on an image
Define spatial resolution
The ability to visualize small structures
Define distortion
The misrepresentation of the size or shape of any anatomic structure
Define magnification
A type of distortion in which the image is larger than the actual object (magnification is present in every image)
Increases with increased OID
And decreased SID
Define contrast resolution
Contrast resolution applies to digital imaging systems and is primarily controlled by bit depth, the number of brightness values possible for each pixel
From the following list, what are the factors that mAs affect in digital imaging
A. OD B. Contrast C. Image noise D. Spatial resolution E. Patient dose
A. OD
C. Image noise
E. Patient dose