Rad Positioning - Test 1 Flashcards
High contrast– long or short scale?
short scale
mostly black & white
Low contrast - long or short scale?
long scale
many shades of gray
OID
object to image receptor distance
SID
source to image receptor distance
Caudad angle
towards the feet
Cephalad angle
towards the head
Osteology
study of bones
Arthrology
study of joints
Tangential projection
CR skims a body part
Image is free of superimposition of
other body parts
Anatomic position
standing upright position facing forward w/palms facing forward
Projection
path/direction of X-ray beam
Cause of most repeat X-rays
poor communication
Coronal / Mid-coronal
longitudinal plane dividing body into anterior and posterior parts
Sagital / Mid-sagital
longitudinal plane dividing body into right and left parts
CR
central ray
IR
image receptor
Lateral decubitus position
recumbent lateral position w/ AP or PA
projection
CR is horizontal
Patient is laying laterally on left side decubitus position… view air/fluid in right/left lung?
view fluid in left lung – gravity
view air in right lung
Patient is laying laterally on right side decubitus position… view air/fluid in right/left lung?
view fluid in right lung – gravity
view air in left lung
Anterior surface of hand
palmar surface
Posterior surface of hand
dorsal surface
Proximal
parts nearer to center of body
Distal
parts farther away from center of body
Lateral
parts away from midline of body
Medial
parts toward midline of body
Supine
lying on back
Prone
lying on front
Superior
towards the top of body
Inferior
towards the bottom of body
Anterior (ventral)
forward/front of body
Posterior (dorsal)
back of body
Type of synovial joint of knee
bicondylar
Type of synovial joint of hips
spheroidal (ball and socket)
Type of synovial joint of wrist
ellipsoid (condyloid)
Type of synovial joint of elbow
ginglymus (hinge)
Axial skeleton
bones of central axis of body
80 bones
skull, vertebral column, ribs, sternum
Appendicular skeleton
bones of upper/lower limbs, shoulder, pelvic girdle
126 bones
3 rules for radiation protection
time
distance
shielding
Erect position
standing up
Recumbent position
lying down
Anterior surface of feet
dorsum surface
not “dorsal”
Posterior surface of feet
plantar surface
Patient getting AP supine chest X-ray
What can be done to reduce magnification?
increase SID
decrease OID
Patient’s right hand is bleeding.
X-ray order is for left hand.
What should you do?
Verify patient’s name and birthday
Double check with technologist/doctor to confirm correct X-ray was ordered
Synarthrodial joint
immovable
Amphiarthrodial joint
limited movement
Diarthrodial joint
freely movable
Dorsal recumbent
lying on back
Ventral recumbent
lying face down
(Right or left) Lateral recumbent
lying on side
Trendelenburg position
recumbent tilted body position with head lower than the feet
Fowler position
recumbent tilted body position with head higher than the feet
Sims position
recumbent oblique position lying on left side with right knee & thigh flexed
Lithotomy position
recumbent supine position with knees/hips flexed and abducted
Dorsal decubitus position
recumbent supine position w/ horizontal CR projection
Ventral decubitus position
recumbent prone position w/ horizontal CR projection
When joint is flexed, the angle between parts is _________
decreased
When joint is extended, the angle between parts is _________
increased
Supination
rotational movement of hand into anatomical position (palm facing up)
Pronation
rotational movement of hand into opposite of anatomic position (palm facing down)
Minimum of ___ projections that are ___ degrees apart for most radiographic procedures
2 projections
90 degrees apart
Minimum of ___ projections when joints are in prime interest area
3 projections:
-AP or PA
-lateral
-oblique
kVp
kilovoltage peak
controls the energy (penetrating power) of X-ray beam
mA
milliamperage
controls the number of X-rays produced
ms
milliseconds
controls the exposure time
mAs
milliampere-seconds
mA x time
exposure time
controls the number of X-rays
Voluntary/involuntary motion can be minimized by
high mA
shorter exposure time
faster IR imaging system
4 factors causing distortion
SID
OID
Object - IR alignment
CR alignment or centering
mAs is controlling factor of _____
density
Contrast
differences in density between adjacent
areas of image
controlling factor: kVp
kVp is controlling factor of _____
contrast
Higher kVp results in higher or lower contrast?
lower contrast
Lower kVp result in higher or lower contrast?
higher contrast
Density
Amount of blackness on image
Primary controlling factor: mAs
Secondary controlling factor: kVp
Influencing factors: SID, screen & IR speed
ALARA
As Low As Reasonably Achievable
What is magnification effect on image if OID is increased/decreased?
increase OID - more magnification
decrease OID - less magnification
How would you explain LPO position?
left posterior against image receptor
Collimation
restriction of X-ray beam
Axial projection
CR is greater than 10 degree angle along long axis of body or part
Effect of small focal spot
results in sharper image
less penumbra
What is resolution effect on image if SID is increased/decreased?
increase SID - better resolution
decrease SID - worse resolution
What is resolution effect on image if OID is increased/decreased?
increase OID - worse resolution
decrease OID - better resolution
Spatial resolution
Sharpness of structures on image
Controlling factors: pixel size, display matrix
Noise
Random disturbance that reduces image clarity
High SNR is desirable
Low SNR is undesirable
3 geometric factors that control image resolution
focal spot size
SID
OID
