Chapter 18 Foot Radiography
• Fractures are characterized by
involvement of the subtalar joint (75%) and
not involving the subtalar joint.
• Stress fractures are common in runners
but typically not seen on radiographs.
• Stress fractures , plantar fascitis or heel
spurs are common repetitive use
conditions.
Foot or Heel Radiography
• Views of the foot and calcaneus are totally
different.
• If a heel injury is suspected, take heel
views and not foot views.
• A 30 degree medial oblique view can be
useful. The oblique and lateral will
demonstrate the subtalar joint.
Foot Radiography
• Foot view must include the tarsal bones,
metatarsals and phalanges.
• A tube angle is used to open the tarsal
bone articulations on the A-P view.
• If the patient is flat footed, no tube angle
would be needed.
Foot Radiography
• The medial oblique view is particularly
useful. It provides:
• A clear view of the tarsal bone including
the calcaneus.
• The 4th & 5th metatarsals
• Intertarsal joints
• Detail of the 5th metatarsal
Foot Radiography
• The “basketball foot” is a traumatic medial
subtalar dislocation resulting from landing
on an inverted foot.
• The “Jones fracture is an avulsion fracture
off the base of the 5th metatarsal.
• Stress fractures of the metatarsals are
generally transverse resulting from
marching or jumping.
Toe Radiography
• Toe radiography can be particularly
challenging.
• The natural curve of the toes toward the
plantar surface of the foot results in
foreshortening and closure of the
interphalangeal joint spaces.
• Besides the A-P, an angled axial view is
used to open the joint spaces.
18.4 Foot A-P
• Measure: A-P at
base of third
metatarsal
• Protection: Apron
• SID: 40” Table Top
• Tube Angle: 10°
cephalad
• Film: 1/2 of 10” x 12
Extremity Cassette
I.D. up
Foot A-P
• Patient seated or lying on
table with the long axis
of the affected foot
centered to table.
• Place cassette on table.
• Have patient place foot
flat on cassette.
• Horizontal CR: base of
third metatarsal
Foot A-P
• Vertical CR: long axis of
foot.
• Collimation Top to
Bottom: distal tibia to
tips of toes.
• Collimation Side to
Side: soft tissue of foot
• Instructions: Remain still
• Make exposure and let
patient relax
Foot A-P Film
• Should demonstrate
toes , metatarsals and
most of the tarsal
bones. The talus and
calcaneus will not be
seen.
• The tube angle will help
open the tarsal joint
spaces.
18.5Foot Oblique
• Measure: A-P at
base of third
metatarsal
• Protection: Apron
• SID: 40” Table Top
• No Tube Angle
• Film: 1/2 of 10” x 12
Extremity Cassette
I.D. up
Foot Oblique
• Patient seated or lying
on table with the long
axis of the affected foot
centered to table.
• Place cassette on table.
• Have patient place foot
flat on cassette.
• The foot is medially
rotated 30 to 40°
• A sponge may be used
under the plantar
surface of the foot.
• Horizontal CR: base of
third metatarsal
• Vertical CR: long axis
of foot.
• Collimation Top to
Bottom: distal tibia to
tips of toes.
• Collimation Side to
Side: soft tissue of foot
• Instructions: Remain
still
• Make exposure and let
patient relax
Foot Oblique
Foot Oblique Film
• Should demonstrate
toes , metatarsals and
most of the tarsal
bones. The talus and
calcaneus will not be
seen.
• The calcaneus will be
well visualized
• Tarsal joint spaces
should be open.
18.6 Foot Lateral
• Measure: Lateral at base
of first metatarsal
• Protection: Lead Apron
• SID: 40” Table Top
• No Tube Angle
• Film: 8” x 10” or 10” x 12”
Extremity depending on
foot size.
Foot Lateral
• Patient lies on the
affected side with lower
leg in lateral position.
• The foot should be
dorsiflexed until the
plantar surface is
perpendicular to ankle.
• The plantar surface of
foot is perpendicular to
film.
Foot Lateral
• The film may be turned
diagonally or the foot
placed diagonally on film
to fit the entire foot on the
film.
• Horizontal CR: base of
1st metatarsal
• Vertical CR: base of first
metatarsal
Foot Lateral
• Collimation Top to
Bottom: to include ankle
to plantar surface soft
tissue
• Collimation Side to
Side: to include from heel
to tips of toes.
• Instructions: Remain still
• Make exposure and let
patient relax.
Foot Lateral Film
• The foot and ankle
should be in a lateral
position.
• The metatarsals and
toes will be
superimposed.
• The distal fibula should
overlie the distal tibia.
• The talotibial joint
space should be open.
18.7 Toes A-P & Axial A-P
• Measure: A-P at 3rd
metatarsal phalangeal
joint or affected toe
• Protection: Lead Apron
• SID: 40” Table Top
• Tube Angle A-P: none
• Tube Angle Axial A-P:
15° cephalad
• Film: 1/4 of 10 x 12
Extremity
Toes A-P & Axial A-P
• A-P : patient places foot
flat on film.
• Horizontal & Vertical
CR: 3rd M-P joint for all
toes or M-P joint of the
affected toe for individual
toe series.
• A-P Axial tube
angle: same as above
but with 15° cephalad
angle.
Toes A-P & Axial A-P
• A-P Axial with
Sponge: a 15° sponge
is placed under toes
instead of angling the
tube. Or
• The Sponge is placed
under the cassette
• Horizontal & Vertical
CR: 3rd M-P joint for all
toes or M-P joint of
affected toe.
Toes A-P & Axial A-P
• Collimation top to
bottom: to include all
M-P joints to tips of toes
or M-P joint to tip of
affected toe.
• Collimation Side to
Side: soft tissue of foot
or individual toe.
• Instructions: Remain
Still
• Expose and let patient
relax
Toes A-P & Axial A-P Film
• A-P is upper right
image.
• A-P Axial is upper left
image. The phalangeal
joints will be open on
the axial view.
• Views must include all
of the affected toe or
toes.
• Note that collimation
was too tight top to
bottom.
18.8 Toes Medial Oblique
• Measure: A-P at
metatarsalphalangeal joints
• Protection: Apron
• SID: 40” Table Top
• No tube angle
• Film: 1/4 of 10” x 12”
or 8” x 10” Extremity
Cassette
Toes Medial Oblique
• Patient places distal foot
on unexposed portion of
cassette.
• Patient medially rotates
lower leg until the plantar
surface forms a 30 to 45°
angle.
• Horizontal CR: 3rd MTP
joint or the affected toe.
Toes Medial Oblique
• Vertical CR: centered to
long axis of foot or the
affected toe
• Collimation top to
bottom: Distal metatarsal
to tips of toes or affected
toe
• Collimation side to
side: soft tissue of foot or
affected toe.
Toes Medial Oblique
• Patient instructions:
Remain Still
• Make exposure and let
patient relax.
• Note that a sponge may
be placed under plantar
surface of foot to control
angle of view . It will also
make it more comfortable
for the patient.
Toes Medial Oblique
• The joint spaces should
be open.
• The distal metatarsal and
tips of the toes should be
visualized.
18.8 Toes Lateral
• Measure: Lateral across
the metatarsalphalangeal joints For
individual toe use A-P
measurement.
• Protection: Apron
• SID: 40” Table Top
• No tube angle
• Film: 1/4 of 10” x 12” or
8” x 10” Extremity
Cassette
• Patient places distal
foot on unexposed
portion of cassette.
• For 1st through 3rd
toes
• Patient medially rotates
lower leg until the
plantar surface forms a
90° angle.
• For 4th and 5th toes
• Patient laterally rotates
foot until the plantar
surface is perpendicular
to film.
1st Toe Lateral
2nd Toe Lateral
• For individual toes, tape
and tongue depressors
are used to clear the
other toes out of the view.
• Without the use of tape
and tongue depressors,
there will be too much
superimposition
• Horizontal CR: 3rd
MTP joint or the
affected toe.
• Vertical CR: centered
to long axis of foot or
the affected toe
• Collimation top to
bottom: Distal
metatarsal to tips of
toes or affected toe
• Collimation side to
side: soft tissue of foot
or affected toe.
3rd Toe Lateral
4th Toe Lateral
• Patient instructions:
Remain Still
• Make exposure and let
patient relax.
• Note that the lateral
surface of the foot is next
to the film.
5th Toe Lateral
• Note that the lateral
surface of the foot is next
to the film.
• The toe need to remain
parallel to the film.
• The 5th toe is the most
challenging lateral toe
view.
Toes Lateral Film
• The joint spaces should
be open.
• The distal metatarsal and
tips of the toes should be
visualized.
• The affected toe should
be free of
superimposition.
Accessory Testing
• Accessories include the cassettes, grids
outside the Bucky, Lead Aprons and
gonadal protection.
• The cassettes and screens are the primary
concern.
• Screens should be cleaned monthly with
screen cleaner. Keeping the darkroom
clean is also important for screen
cleanliness.
23.4 Screen Contact Testing
• Procedure:
• Clean screens and let
them dry. Use screen
cleaner design for the
screen used.
• With a felt tip pen, write
an identification number
on the screen next to the
I.D. and on the back of
the cassette.
• Load cassettes.
Screen Contact Testing
•
•
•
•
Procedure:
Set SID to 40” Table Top
Place cassette on table.
Place wire mesh tool on
cassette.
• Set collimation to film
size.
• Make exposure and
process film.
Screen Contact Testing
• Procedure:
• Hang film on view box.
• Step back 72” from view
box and view film.
• Areas of increased
density or loss of
resolution indicates
poor contact or stained
screens.
Screen Contact Testing
• Procedure:
• The I.D. # will help you
find a cassette that
needs to be cleaned or
taken from service.
• Frequency of tests:
semiannual
•
Poor Screen
Contact
There is a loss of
detail in the thoracic
and lumbar spine
due to poor screen
contact.
• This was a new
cassette.
•
Poor Screen
Contact
Note the blurry image
in the spine but sharp
image of the ribs.
• The screens were not
in proper contact in
the middle of the
cassette due to a bow
in the cassette back.
Screen Cleaning
• Materials needed:
• Screen Cleaner
designed for type of
screens used.
• 4 x 4 gauze or cotton
balls
• Tape & Pen
Screen Cleaning
• Procedure:
• Unload cassette if
contact is not being
tested.
• Apply cleaner with
gauze.
• Wipe excess off with
dry gauze.
Screen Cleaning
• Leave open to air dry.
• Make sure cassette #
is still legible.
• After dry, reload
cassette.
Screen Cleaning
• Record date on tape
and place on back of
cassette.
• By having each
cassette identified,
selected cassette can
be cleaned as
needed.
Screen Cleaning
• California Department of Radiologic Health
recommends cleaning screens monthly.
• Should definitely be done quarterly and
sooner as needed when artifacts are
identified on films.
• Never use alcohol or detergents not
designed for cleaning screens.
Cassette Care
• Methods to get the maximum life from cassettes:
– Avoid dropping the cassettes
– Open only far enough the change films
– Keep outside of cassette clean and dry.
– Keep screens clean
– Store on end.
Dirty or Damaged Screens
• Dirty or damaged
screen will cause
white spots on the
image.
Dirty & Damaged Screens
• The white spots on
this film are the result
of damaged or worn
out screens.
• Never use alcohol or
detergents to clean
screens.
Speed Matching
• After looking for screen contact problems:
• Measure speed of cassettes by reading density
with the Densitometer. The density of the
exposed area should not vary more than ± 0.05
OD.
• As screen age, they loose speed.
• Always make sure the light spectrum of the
screens and film are matched.
23.5 Apron and Gonad Shield
Testing
• Lead aprons and
shields should be
tested semiannually
for defects
• Aprons with defective
lead provide little
protection for the
patient.
Apron and Gonad Shield Testing
• Tools needed:
– 14” x 17” cassette
– View Box
• Coat Apron Procedure:
• Drape apron over Bucky
• Place cassette in Bucky
make exposures in upper
and lower Bucky slots.
Apron and Gonad Shield Testing
• Coat Apron Procedure:
• Note that this is the same
test as used for grid
alignment.
• Process films
• View films on view box:
Apron and Gonad Shield Testing
• Half Apron and Small
Shield Procedure:
• Place cassette on table
• Set SID at 40”
• Place apron or shields
on cassette.
• Make exposure and
process the film.
Apron and Gonad Shield Testing
• Viewing the test films:
– Note creases in the
lead.
– Full holes will produce
a black area on the
film.
– If cracks or defects are
in the area that should
cover the gonads,
replace apron.
Care of Aprons
• Never fold aprons
• Store flat or hung on apron rack
• Use only aprons with the lead equivalency
of 0.5mm for patient and staff protection.
• Do not use as lead blockers for extremity
films.
• Protect from heat and direct sun light.
Grid Uniformity Testing
• Procedure is the same as testing the
Bucky Grid.
• Place homogenous phantom or lead apron
over grid that is taped to the top of the
cassette.
• Make exposure and look for density
changes and grid damage.