Ch. 1 Flashcards
What are Ethics
Moral responsibility and the science of appropriate conduct toward others
Image Receptors
The device that receives the energy of the x-ray beam and forms the image of the body part
What are the 4 types of IR’s
- Cassette w/ film
- Photostimulable storage phosphor image plate (PSP IP)
- Solid-state digital radiography
- Fluoroscopic image receptor
Digital Radiography
- Brightness of displayed image
- primarily controlled by rescaling
Screen-film Radiography
- Optical density (overall blackening of film)
- Controlled by mA, Exposure time (sec), and milliampere-seconds (mAs)
What is Contrast?
Differences in adjacent densities (low/high)
- Controlled by bit depth in digital radiography
- Controlled by kVp in screen-film radiography
Spatial Resolution
Ability to visualize small strucutres (recorded detail)
- Controlled by IP phosphor, geometry, distance, film, focal spot size, etc.
Distortion
Misrepresentation of the size or shape of a structure
- Shape distortion controlled by: alignment, central ray, anatomic part, IR, and angulation
Magnification is what?
A size distortion
- present in all images
- controlled by OID and SID
Which positions are radiographs usually viewed?
In anatomic position
**Exception: Hands, wrists, feet, and toes
Radiographer is responsible for what?
- Patient care during an image procedure
- Obtaining patient’s clinical history
(verify correct procedure ordered, observe conditions) - Keeping room clean
What tasks are involved in Infection Control?
- Handwashing
- using appropriate and required protection when there are infectious organisms in close contact
- Protecting IR from body fluids
- Clean IRs and equip regularly
What are the 3 types of motion?
Involuntary, Voluntary, and Equipment
Involuntary Motion
Caused by: heartbeat, chills, peristalsis, tremor, spasm, and pain
Primary control: Use short exposure time
Voluntary Motion
Lack of control of voluntary motion caused by: nervousness, discomfort, excitability, mental illness, fear, age, and breathing
How do you control Voluntary Motion?
- Giving clear instructions
- Providing patient comfort
- Adjusting support devices
- Applying immobilization
- Decreasing exposure time
Image ID Contains what?
Date, Patient’s name and ID #, Right or left side marker, Institution identity
When are side markers usually put on an image ?
During the procedure by the technologist
What are the 3 general IR positions?
Longitudinal, horizontal, corner-to-corner
-Position name based on IR relation to long axis of body
Central Ray Direction
CR always centered to IR (unless IR placement is being used)
Source-Image Receptor Distance
The distance from the anode inside the x-ray tube (source) to the IR
-Abbreviation SID
What does SID affect?
- Magnification
- Spatial resolution
- patient dose
What needs to be on every radiographic image?
Side markers (right or left)
Longer SID reduces What?
magnification
Longer SID increases what?
spatial resolution
What is Collimation?
Restriction of the x-ray beam to only the anatomy of interest
What are the shielding guidelines for gonads?
Shield if
- gonads lie within or close to x-ray field
- clinical objective is not comprised
- patient has reasonable reproductive potential
What pathologic conidtions/diseases require a decrease in technique?
- Old age
- Pneumothorax
- Emphysema
- Emaciation
- Degenerative arthritis
- Atrophy
What pathologic conditions/diseases require an increase in technique?
- Pneumonia
- Pleural effusion
- Hydrocephalus
- Enlarged Heart
- Edema
- Ascites
What needs to be cleaned after every patient?
The IR; must keep IR clear of any body fluids
What are IP phosphors sensitive to?
Hypersensitive when split cassette technique is used
- more sensitive to scatter radiation
What should be in every x-ray room as well as on mobile machines?
Technique charts
What is on a technique chart?
Specific projections performed in the room and also includes exposure factors for each projection
What is key in all imaging procedures
Communication!
-Empathetic communication is essential
What is most effective when imaging patients that are obese?
Locating the jugular notch
What are a few primary factors when incorporting exposure techniques during a procedure?
-mAs, kVp, Grid, IR or collimated field dimensions, SID, etc.
What is sterilization
Destruction or killing of all microorganisms
What are two main purposes collimation serves for?
- Minimizes patient exposure
- Reduces scatter radiation
What is the IR in Computed Radiography (Digital Imaging)?
In Computed Radiography, the IR is an imaging plate (IP) composed of a phosphor plate
-Image is displayed on a monitor
What type of Imaging uses solid-state Image Receptors?
Digital Radiography (DR)
Attention to detail is key to quality of what?
Digital Imaging (DR)
What is not essential to image quality in Digital Radiography?
Optimum kVp
*slightly higher kVp yields better image than slightly lower kVp
What are exposure numbers used to determine in Digital Radiography?
Whether an image is within quality range
What is effective when trearing obsese patients?
- Locating jugular notch
- Making sure the table can support their weight
- providing support and assistance to maximize patient comfort and security
What is Contrast Resolution?
Contrast Resolution applies to digital imaging systems, a wide range of contrast levels is produced among various radiographic exams performed.
-controlled by bit dedpth
What does Long scale mean regarding Contrast?
It means that the Image has low contrast
What does Short scale mean regarding Contrast?
It means that the Image has high contrast
What are the 6 factors that control Spatial Resolution?
- IP phosphor (digital)
- Flat panel detector
- Motion
- Distance
- Geometry
- Focal spot size
What 5 factors control Shape Distortion of a body part?
- Alignment
- Angulation
- Central Ray
- IR
- Anatomic part
List 3 ways a patient’s colon may be cleansed for an abdominal examination.
-Limited diet, laxatives, and enemas
The rhythmic motion of smooth muscle structures is called what?
Peristalsis
What is OID?
Object-to-Image Receptor Distance
-how far the body part is from the IR
What is SID?
Source-to-Image Receptor Distance
-how far the x-ray tube is from the IR
What exam will give the highest dose to a female?
Lumbar Spine Exam : Exposure of 4 mGy
What exam will give the highest dose to male?
Pelvis Exam: Exposure of 3 mGy
How are extremity images viewed?
With digits facing upwarad
Low contrast images usually display many or few density levels?
Many density levels
High Contrast images usually display many or few density levels?
Few density levels
Optical Density (OD)
The degree of blackening when associated w. radiographic film and as brightness when appearance on a digital display monitor is described
