Diagnostic imaging

Positioning anatomy
-What does each accessory view show you/why is it done?
-What anatomy is best seen on:
-Anterior oblique cervical view (obliques show IVFs, which one?)
-Posterior oblique cervical view
-Anterior oblique lumbar view (obliques show pars, which one?)
-Posterior oblique lumbar view

Positioning tube tilts
-Cervical views with tube tilts
-APLC: 15˚ cephalic
-Anterior oblique: 15˚ caudal (down a cute butt)
-Posterior oblique: 15˚ cephalic (up a cute face)
-Swimmer’s view: sometimes 5˚ caudal
-Pillar view: 35˚ cephalic
-Thoracic views: no tube tilts, but these views are unique b/c they use compensating filters
-Lumbar/pelvic/sacrum views with tube tilts
-Frontal angulated L5-S1 (AP L5-S1 spot): 30˚ cephalic
-AP sacrum (tilt up view): 15˚ cephalic
-Upper extremities:
-wrist: scaphoid view: 20˚ cephalic
-all extremity views that have tube tilts are cephalic tube tilts
-Lower extremities:
-knee (not patella)
-AP knee: 5˚ cephalic
-Lateral knee: 5˚ cephalic
-“nickel knee shots”
-patella: tangential/sunrise/skyline/prone Settegast view: 10˚ cephalic (sun rises at 10 am in radiology)
-foot
-AP (dorsal plantar view): 10˚ cephalic
-Medial oblique: 10˚ cephalic
-patient has 10 toes visible on these 2 views

Positioning FFD = TFD
-focus to film distance or tube to film distance
-all extremities start at 40″ TFD and are only modified if a tube tilt is present
-formula: for every 5˚ of tube tilt, subtract 1 inch of TFD
-starting TFD minus (tube tilt/5) = TFD
-Spine
-all spinal views have starting TFD of 40″ except these (starting at 72″): LCN, anterior and posterior oblique, cervical flexion, cervical extension (cervical air-gap rule), AP full spine (Gonstead)
-the same formula applies to all spinal views

Positioning grids
-all spinal views need a grid/bucky except cervical view with starting TFD of 72″ (air gap rule)
-even though these views don’t need a grid, you can still use one
-all extremities above the elbow need a grid (everything below elbow and elbow itself does not need grid)
-all extremities above the knee need a grid
-knees may need a grid of they measure larger than 11-13 cm

Positioning breathing instructions
-extremities/cervical: don’t move or don’t move, don’t breathe
-thoracic/lumbar/pelvis/ribs
-above the diaphragm (thoracic, ribs 1-9): breathe all the way in and hold
-below the diaphragm (lumbar, pelvis, ribs 10-12): breathe all the way out and hold

Positioning patient positioning
-look at the name for clues
-general rule: the name will tell you what side and what part of the patient is touching the cassette/grid
-exceptions: lateral views of an upper extremity (these are placed w/ the medial side touching the cassette/grid)

Positioning central ray
-look at the name: scaphoid view: CR goes through the scaphoid
-imagine the entire body part; CR usually goes through the center of that body part
-specific views
-thoracic, chest, ribs 1-9: set film height, then center CR to film
-film height = 1-2 inches above C7/vertebral prominens

Positioning random facts
-swimmer’s view is controversial in terms of TFD, tube tilt, film size, and collimation; it is taken to see the cervicothoracic junction
-lateral elbow view is performed w/ the patient elbow bent at 90˚ and thumb up
-all chest views are taken at 72″ TFD and are above diaphragm
-chest views are only views with 100 or more kVp
-gonad shields are not used if they obscure anatomy
-10 day rule for pregnancy