EXAM #1+2 (Ch. 1 + 2)* Flashcards
define: ethics
moral responsibility and the science of appropriate conduct towards others
ASRT
define: image receptors
device that receives the energy of the x-ray beam and forms the image of the body part
what are [4] types of image receptors?
- cassette with film
- PSPIP (photostimulable storage phosphor image plate)
- solid-state digital detectors (portable)
- fluoroscopic image receptor
screen-film radiography:
what [3] things control optical density
- mA
- exposure time (seconds)
- miliampere-seconds (mAs)
[*] define: contrast/contrast resolution
what controls it in digital radiology?
what controls it in screen-film radiography?
differences in adjacent densities (low/high)
digital: bit depth
screen-film: kVp
[*] define: spatial resolution / recorded detail
what [8] things control it?
ability to visualize small structures
- IP phosphor (digital)
- DEL size (digital)
- geometry
- distance
- motion
- focal spot size
- intensifying screen
- film
define: distortion
what [5] things control it?
misrepresentation of the size/shape of a structure
- alignment
- central ray
- anatomic part
- image receptor
- angulation
true or false?
magnification is size distortion
true, magnification is (size) distortion
true or false?
all images are affected by distortion
true, all images are affected by distortion
what controls size distortion magnifcation
OID (object-source receptor distance)
SID (source-image receptor distance)
true or false?
radiographs are usually viewed in anatomic position
true
[*] what are [4] exceptions when radiographs are NOT viewed in the anatomic position?
how are they viewed?
extremities
- hands
- wrists
- feet
- toes
viewed from perspective of the tube with distal ends toward ceiling
what is an RT responsible for during basic patient care
verify correct procedure is ordered
observe conditions or abnormalities to relay to radiologist
what is a radiography responsible for during care of examination room
what [3] things are to be stocked?
keeping room clean (IRs + equipment) to minimize transmission or infection and provide patient confidence
stock:
• linens
• contrast
• ancillary equipment
what is the most effective and efficient method to control spread of microorganisms?
handwashing
when should appropriate and required protection be used?
when there is a possibility of coming into contact with infectious organisms
what should IRs be protected from?
body fluids
imaging of motion ____ image quality
imaging of motion ruins image quality
what are [3] types of motion?
- voluntary
- involuntary
- equipment
[*] what are [6] things that cause involuntary motion?
what is the primary control of involuntary motion?
- heartbeat
- chills
- peristalsis
- tremor
- spasm
- pain
primary control: use short exposure times
[*] what are [7] things that cause voluntary motion?
what are [5] things that control imaging of voluntary motion?
causes: • nervousness • discomfort • excitability • mental illness • fear • age • breathing
controls: • clear instructions • patient comfort • adjusting supporting devices • apply immobilization • decreasing exposure time
what are [4] things that are required ID items to be printed on radiographs?
- date
- name/number
- right or left marker
- institution
when are side markers put on?
during the procedure
what are [3] general IR positions?
which is most often used?
- longitudinal
- horizontal
- corner-to-corner
most often used: longitudinal
CR is always centered to ____.
unless…?
CR is always centered to IR
unless: IR displacement is being used
the CR should be angled through the part of interest to [4] things
- avoid superimposition of structures
- straighten out a curved structure
- align the CR through an angled
- avoid distortion of an angled structure
define: source-image receptor distance
abbreviation?
affects [3] things
distance from the anode in x-ray tube (source) to the IR
SID
- magnification
- spatial resolution
- patient dose
[*] longer SID ____ magnification and ____ spatial resolution
A. increases, increases
B. reduces, reduces
C. increases, reduces
D. reduces, increases
D. reduces, increases
true or false?
SID is standardized for examinations and must be indicated on technique charts
true
when are the following SID used?
40 inches?
48 inches?
72 inches?
40 inches: traditionally used on most examinations
48 inches: recent increase in many facilities
72 inches: used on examinations with increased OID to reduce magnification
define: collimation
[2] purposes of collimation?
restriction of x-ray beam to only the anatomy of interest
- ) minimizes patient exposure
- ) reduces scatter radiation
true or false?
the gonads may be irradiated for some examinations
true
shielding should be used when practical
what are the [3] shielding guidelines, when should gonads be shielded?
gonads lie within or close to x-ray field
clinical objective is not compromised
patient has reasonable reproductive potential
what does DR stand for?
digital radiography
attention to ____ is key to quality imaging
attention to quality is key to digital imaging
true or false?
optimum kVp is essential to image quality in digital imaging
false
slightly higher kVp yields better image than slightly lower kVp
postprocessing can be used to correct
true or false?
IP phosphors are hypersensitive, so when split cassette technique is used, the unexposed side must be protected
true
true or false?
overexposure or underexposure is determined by displayed image
false
exposure numbers are used when determining whether the image is properly exposed
true or false?
IP phosphors are more sensitive to scatter radiation
true
some examinations may require a grid to reduce scatter
____ should be in every room and on mobile machines
technique charts
what are [2] purposes for technique charts?
- specifies projections performed in room
* includes exposure factors for each projection
[*] what [6] pathologic conditions require a DECREASE in technique?
- old age
- atrophy
- degenerative arthritis
- emaciation
- emphysema
- pneumothorax
[*] what [6] pathologic conditions require an INCREASE in technique?
- pneumonia
- pleural effusion
- hydrocephalus
- enlarged heart
- edema
- ascites
research shows that obesity has ____ in the last ____ years
research shows that obesity has doubled in the last 15 years
define: obesity
increase in body weight by an excessive accumulation of fat
40+ BMI is morbidly obese
[2] empathic communication keys
- avoid mentioning weight
* explain what is required to safely move and/or transfer the patient
true or false?
prod patients if they’re obese to find palpable landmarks
false
never prod obese patients unnecessarily
define: compensating filters
assist in achieving even density on anatomic structures that vary in tissue thickness
what would happen without compensating filters?
images of anatomy with varying tissue thickness would require two exposures to see the same thing in an x-ray image
when is a wedge filter used?
where tissue density varies gradually from one end to the other
(AP of thoracic spine)
when is a trough filter with a double-wedge used?
for areas of the body where the density in the center is greater than the edges
(PA of chest)
when is a boomerang filter used?
conforms to shoulder to improve density
when is a ferlic filter used?
AP and PA oblique projections of shoulder
when is a ferlic collimator-mounted filter used?
lateral projections of the cervicothoracic region (swimmer’s) and axiolateral projections of hip
what are [3] physical properties of filters
- shape
- composition
- placement
what is the most commonly used filter?
wedge filter
what [2] materials are most commonly found in filters?
aluminum and high-density plastics
what is the benefit of using high-density plastic filters over aluminum filters?
aluminum filters block light field and positioning must be complete before mounting filter to collimator
what is the boomerang filter made out of?
silicone rubber
what are the [2] placements of filters?
- contact (on patient or between patient and IR)
* collimator-mounted
ferlic swimmer’s filter improves the quality of…?
lateral projection of cervicothoracic spine
use of scoliosis filters in AP and lateral projections
AP – wedge over cervical and thoracic regions
lateral –two double-wedge
what kind of filters are used for digital fluoroscopy
convex and concave cone-shaped filters
compensate for round image intensifier
what kind of filters are used for computed tomography?
bow-tie shaped filters compensate for rounded shape of head
why are two hands needed when attaching collimator-filters?
one below to catch the filter if it does not attach properly so it doesn’t land on the patient
[*] what are CR phosphors sensitive to?
scatter radiation
[*] define: IR
image receptor - receives energy of x-ray and forms image
[*] what needs to be on every image?
side markers
[*] what group tells us about blood and body fluid recommendations
CDC
[*] what needs to be cleaned after every patient
the tabletop
[*] define: OID
object-to-image receptor distance
how far body is to IR
[*] define: SID
source-to-image receptor distance
hor far x-ray tube is to IR
magnification increases with increased ____ and decreased ____
magnification increases with increased OID and decreased SID
[*] males/females – what exams give highest dose (one Q each)
males: pelvis (3mGy)
females: lumbar spine (4mGy)
[*] sanitation—the laws of ____ and ____ must be followed
the laws of asepsis and prophylaxis must be followed
