100+ Positioning
Tricks of the Trade
WCEC 2011
Dennis Bowman RT(R)
Clinical Instructor
Community Hospital of the Monterey Peninsula (CHOMP)
Cabrillo College
Getting the part perfectly centered




Here is what I mean by 1 finger
collimation.
The coconut experiment.


Bucky vertical and tube level with floor.
The proper centering criteria is the perfect
place to start.
Just make sure you don’t end there, ever!!
You need to always double check that you
have all four sides on with the perfect
amount of collimation or anatomy.
Most of the positioning I do does not have
a particular centering – I just look at the
top, bottom and both sides of the light.
The following slides will prove how
important it is to have a horizontal beam
when looking for air/fluid levels.
All mention of bucky also means the
coconut (which really means the patient).
Bucky vertical and tube 15 degrees caudad.
1
Bucky leaning back 15 degrees and tube 15
degrees caudad. They are parallel.
Bucky is vertical and tube is 15 degrees
cephalad.
Bucky is angled back 15 degrees and tube is
level with the floor.
This PA erect abdomen is the perfect example of free
air that could be missed if taken with an angle beam.
As is this Waters view with a subtle
air/fluid level in the right maxillary sinus.
Right Lobes
2
Right Upper Lobe
Right Lower Lobe
Left Upper Lobe
Right
Middle Lobe
Left Lung
Left Lower Lobe
3
Chest Diaphragm Full Inspiration
Chest Diaphragm In Middle
Chest Diaphragm Full Expiration
Lateral spines and why
we do left versus right





Almost all x-ray rooms are set up so when the
tech walks up to the table, the patient is lying
down with their head towards your left side.
This is so the Anode Heel Effect will take affect
Left laterals are best because the patient is facing
away from you and you can easily see their
posterior side.
At the upright bucky, it does not make any
difference whether you do a right or left lateral.
Best so that their back side is still easiest to see
Vertebral Column Landmarks
How to get a standing patient
to only move 1 inch to the side

The following photos have colored lines
which are exactly 1 inch apart.
4
This is our starting place. The patient is centered side
to side with the vertical light over the green line.
Here the patient has moved just the right foot to the
right 1 inch, causing his body to shift to the right 1”.
Here the patient has moved both feet 1” to the right,
causing his body to move 2” laterally to the right.
When shooting trauma views, often
your patient cannot be moved into
the oblique position. When this
occurs, how do you know which
way to angle the tube?
This example will be for a mortise oblique ankle.
You patient would be unable to do this rotation.
What you need to do is imagine it and see that the
CR will enter through the lateral malleolus first.
5
Then you need to imagine that as the ankle moves
back to the AP position that they are in, which way
would the tube need to angle to make sure the CR
is still entering the lateral malleolus first.
Now you end up with the tube angled the same
amount (15-20 degrees) as you would have rotated
the ankle. As you can see the ankle has not been
moved and the CR is entering the lateral malleolus.
A quick little experiment to
show the differences in SID’s…..



Classic distances are (were) 40” or 44” and
72.”
Patients are much larger now.
Typical large patient for abdomen…



51” using fluoro table bucky
63” using movable table bucky
72” using upright bucky
6
Here’s a reminder that your lead aprons are
made to protect you from scatter radiation only,
not the primary beam.
40”
85 kV @ 16 mAs
Two .5 mm lead aprons covering the R marker.
40” 85 kV @ 16 mAs (Average hip technique)
One .5 mm lead apron covering the R marker
40”
85 kV @ 16 mAs
Three .5 mm lead aprons covering the R marker.
7
40”
85 kV @ 16 mAs
Four .5 mm lead aprons covering the R marker.
40”
85 kV @ 16 mAs
Five .5 mm lead aprons covering the R marker.
72” 85 kV @ 3.2 mAs (Average non grid chest)
One .5 mm lead apron covering the R marker.
72”
85 kV @ 3.2 mAs
Two .5 mm lead aprons covering the R marker.
72”
85 kV @ 3.2 mAs
Three .5 mm lead aprons covering the R marker.
72”
113 kV @ 4 mAs (Average gridded chest)
One .5 mm lead apron covering the R marker.
8
72”
113 kV @ 4 mAs
Two .5 mm lead aprons covering the R marker.
40”
113 kV @ 4 mAs
Three .5 mm lead aprons covering the R marker.
40”
113 kV @ 4 mAs
Four .5 mm lead aprons covering the R marker.
40”
113 kV @ 4 mAs
Five .5 mm lead aprons covering the R marker.
This experiment was to show the difference in
dose getting through a .25, .375 and .5 equivalent
lead shield (using the .5 as the standard). The
tube is set at 40” and is collimated to a 12”x12.”
The .25 and .375 aprons are letting through anywhere
between 1.3 to over 22.3 times more radiation!!
Lead Apron Study, Using Abdomen Phantom w/ meter perpendicular,
meter 2" away from left side. Doses are an average of three different
types of lead aprons.
Lead (mm)
kV
mAs
Dose (mR)
Dose increase
compared to
0.5mm lead (%)
Dose increase
compared to 0.5mm
lead (x)
None
0.25
0.375
0.5
81
81
81
81
4
4
4
4
0.89
0.04
0.007
0.003
29567%
1233%
133%
296.7
13.3
2.3
None
0.25
0.375
0.5
81
81
81
81
8
8
8
8
1.84
0.08
0.02
0.008
22900%
900%
150%
230.0
10.0
2.5
None
0.25
0.375
0.5
81
81
81
81
16
16
16
16
3.76
0.173
0.043
0.023
16248%
652%
87%
163.5
7.5
1.9
None
0.25
0.375
0.5
102
102
102
102
2
2
2
2
0.91
0.063
0.017
0.01
9000%
530%
70%
91.0
6.3
1.7
None
0.25
0.375
0.5
102
102
102
102
4
4
4
4
1.88
0.137
0.037
0.025
7420%
448%
48%
75.2
5.5
1.5
None
0.25
0.375
0.5
102
102
102
102
8
8
8
8
3.81
0.283
0.093
0.048
7838%
490%
94%
79.4
5.9
1.9
None
0.25
0.375
0.5
125
125
125
125
1
1
1
1
0.79
0.67
0.13
0.03
2533%
2133%
333%
26.3
22.3
4.3
None
0.25
0.375
0.5
125
125
125
125
2
2
2
2
1.61
0.157
0.053
0.04
3925%
293%
33%
40.3
3.9
1.3
None
0.25
0.375
0.5
125
125
125
125
4
4
4
4
3.29
0.34
0.14
0.067
4810%
407%
109%
49.1
5.1
2.1
9
Here’s an experiment to see the difference
between .25mm and .5mm lead aprons at a
distance of 2’-6’.
The abdomen phantom is on top of 6 inches
of polyethylene to simulate a 250 lb patient.
The roller shield has a .5mm lead.
Comparison of Lead Apron Protection
This yellow apron is .25mm.
Distance Thickness
(ft)
(mm)
0.5
2
0.25
0.5
3
0.25
0.5
4
0.25
0.5
5
0.25
0.5
6
0.25
0.5
2
0.25
0.5
3
0.25
0.5
4
0.25
0.5
5
0.25
Angle
(deg)
90
90
90
90
90
90
90
90
90
90
60
60
60
60
60
60
60
60
Dose
(mR)
0.012
1.595
0
0.834
0
0.546
0
0.338
0
0
0
1.057
0
0.62
0
0.389
0
0
The cumulative dose through a lead apron during
1 minute of fluoroscopy at various distances. A
phantom is supine with 6 in of polyethylene blocks
under it. In room flouro II is 4in above midline of
phantom. The ion chamber records measurements
perpendicular (90 deg) to the migsagittal plane of
the phantom and 60 degrees off of perpendicular.
How much Dose are you getting from
scatter radiation coming out of your patient?
We did this experiment many times with and without
grids, at 115 and 85 kVp, and at 3 different angles.
This one is taken at 90 degrees to the patient.
10
This one is taken at 45 degrees to the patient.
And this one we are calling 0 degrees.
Here are all the doses for 0, 45 and 90 degrees (arrows at 6’)
This experiment used the arm/hand phantom and a 10x12
CR cassette. We set it up where many techs stand when
making a PCXR exposure. This photo and the following
two images have the cassette at: 9’ from the patient at 15
degrees and 4’ from tube at 30 degrees.
85@3.2
and
Dose exposure due to scatter
from Portable Chest Xrays
Angle of
Chamber
(Deg)
90
90
90
90
90
90
45
45
45
45
45
45
45
45
0
0
0
0
0
0
0
0
0
0
0
Distance
(ft)
1
2
3
4
5
6
1
2
3
4
5
6
7
8
6
7
8
9
10
11
12
13
14
15
16
Dose #1
(microR)
96.0
42.7
21.1
13.3
10.6
6.9
195.5
79.3
38.3
24.3
16.2
11.6
9.4
7.1
34.0
24.5
17.4
14.0
10.5
8.4
6.3
5.3
0.0
0.0
0.0
Dose #2
(microR)
94.6
42.0
22.0
12.7
9.0
6.1
196.2
80.7
39.2
23.8
17.9
12.0
9.1
6.4
33.1
23.0
16.0
14.2
11.6
8.9
7.5
6.4
0.0
0.0
0.0
Chest technique of
85@3.2 wasused for all
exposures. Ionization Chamber angle is
measured from mid sagittal plane.
Average
Dose
(microR)
95.3
42.4
21.6
13.0
9.8
6.5
195.9
80.0
38.8
24.1
17.1
11.8
9.3
6.8
33.6
23.8
16.7
14.1
11.1
8.7
6.9
5.9
0.0
0.0
0.0
115@4
Dose exposure due to scatter
from Portable Chest Xrays
Angle of
Chamber
(Deg)
90
90
90
90
90
90
45
45
45
45
45
45
45
45
0
0
0
0
0
0
0
0
0
0
0
Distance
(ft)
1
2
3
4
5
6
1
2
3
4
5
6
7
8
6
7
8
9
10
11
12
13
14
15
16
Dose #1
(microR)
316.0
125.8
68.3
42.2
27.1
19.7
744.0
295.0
150.7
98.3
66.2
48.6
33.6
27.6
76.0
50.5
39.3
32.3
25.4
22.4
17.0
14.3
12.6
10.2
8.3
Dose #2
(microR)
320.0
127.2
67.6
41.0
28.3
19.7
778.0
295.0
151.2
97.6
65.2
47.4
32.7
27.5
75.1
51.8
39.8
31.9
27.0
21.8
16.9
14.4
12.5
9.9
8.2
Average
Dose
(microR)
318.0
126.5
68.0
41.6
27.7
19.7
761.0
295.0
151.0
98.0
65.7
48.0
33.2
27.6
75.6
51.2
39.6
32.1
26.2
22.1
17.0
14.4
12.6
10.1
8.3
Chest technique of
115@4 wasused for all
exposures. Ionization Chamber angle ismeasured
from mid sagittal plane.
Yep, read it and weep. Even though the scatter dose
is way down in the micro R’s, there is enough
radiation to make this image – with 1 exposure!!
These are the images after 5 exposures.
11
This photo and the following 2 images were taken with
the phantom/cassette 12’ from the patient directly
behind the tube (which is 6” from the patient).
Here is the 5 exposure version.
Getting the ESE on the abdomen phantom.
The 85 kV image had 6.0 microR’s
and the 115kv image had 17 microR’s.
If you’re thinking like we were, then you are
wondering how much (if any) of that dose scattered
from the tube, not the patient. It turns out that at 12”
from the tube the dose from the tube was so small
that the dosimeter could not read it.
Set-up for exit dose with the thorax phantom.
12
“Fake” body Phantom using
polyethylene blocks and 500cc saline bags.
Anterior Quarter
1.05 R
Posterior Quarter
0.195 R
-50.7%
-90.8%
85 kVp @ 14 mAs
45’’
Entrance Dose 2.13 R
Middle
Exit
0.469 R
0.051 R
14x17
0%
-78.0%
-97.6%
13
Under Grid (in bucky)
0 Degrees
90 Degrees
0.0075 R
45 mR
11.1 mR
-99.6%
0% change
25% less
One more experiment to show how much of the
exposure scatters and in what direction. All
exposures were taken at 6’, 85kV @ 3.2 mAs.
The Ion chamber was put at 4’ from the
phantom.
45 Degrees
135 Degrees
32.2 mR
28% less
8.9 mR
80% less
14
180 Degrees
21.6 mR
52% less
Scatter around the body after a PCXR
Dose exposure Due to Scatter From Portable Chest X-Rays
Angle of
Chamber
(Deg)
Dose #1
(microR)
Dose #2
(microR)
Dose #3
(microR)
Average Dose
(microR)
0
45.3
45.4
44.4
45.0
1
45
31.7
32.8
32.2
32.2
28%
Radiation
Reduction (% )
90
10.7
11.2
11.4
11.1
75%
135
8.8
8.2
9.7
8.9
80%
180
22.3
21.2
21.4
21.6
52%
Chest technique of 85kV, 3.2mAs @ 4ft was used for all exposures. Ionization
Chamber angle is measured from mid sagittal plane with 0 deg being 4ft in front
of phantom and 180 deg directly behind the phantom. Exposures where made
with AMX portable shooting at chest phantom on a table by itself.
To properly rotate the skull/facial bones/mandible
into a lateral position: Begin by having patient PA
and turn head as far as they can without straining.
Keeping head, neck and torso in that position,
start rotating the patient’s entire body
towards the lateral position.
Keep the rotation going…
…Until the skull is lateral. There will be
some OID that is unavoidable, but the
patient will easily be able to hold this position.
15
Here’s a reminder that your lead aprons are
made to protect you from scatter radiation only,
not the primary beam.
40” 85 kV @ 16 mAs (Average hip technique)
One .5 mm lead apron covering the R marker
40”
85 kV @ 16 mAs
40”
85 kV @ 16 mAs
Two .5 mm lead aprons covering the R marker.
Three .5 mm lead aprons covering the R marker.
40”
85 kV @ 16 mAs
Four .5 mm lead aprons covering the R marker.
40”
85 kV @ 16 mAs
Five .5 mm lead aprons covering the R marker.
16
72” 85 kV @ 3.2 mAs (Average non grid chest)
One .5 mm lead apron covering the R marker.
72”
85 kV @ 3.2 mAs
Two .5 mm lead aprons covering the R marker.
72”
85 kV @ 3.2 mAs
Three .5 mm lead aprons covering the R marker.
72”
113 kV @ 4 mAs (Average gridded chest)
One .5 mm lead apron covering the R marker.
72”
113 kV @ 4 mAs
Two .5 mm lead aprons covering the R marker.
40”
113 kV @ 4 mAs
Three .5 mm lead aprons covering the R marker.
17
40”
113 kV @ 4 mAs
Four .5 mm lead aprons covering the R marker.
This experiment was to show the difference in
dose getting through a .25, .375 and .5 equivalent
lead shield (using the .5 as the standard). The
tube is set at 40” and is collimated to a 12”x12.”
Here’s an experiment to see the difference
between .25mm and .5mm lead aprons at a
distance of 2’-6’.
40”
113 kV @ 4 mAs
Five .5 mm lead aprons covering the R marker.
The .25 and .375 aprons are letting through anywhere
between 1.3 to over 22.3 times more radiation!!
Lead Apron Study, Using Abdomen Phantom w/ meter perpendicular,
meter 2" away from left side. Doses are an average of three different
types of lead aprons.
Lead (mm)
kV
mAs
Dose (mR)
Dose increase
compared to
0.5mm lead (%)
Dose increase
compared to 0.5mm
lead (x)
None
0.25
0.375
0.5
81
81
81
81
4
4
4
4
0.89
0.04
0.007
0.003
29567%
1233%
133%
296.7
13.3
2.3
None
0.25
0.375
0.5
81
81
81
81
8
8
8
8
1.84
0.08
0.02
0.008
22900%
900%
150%
230.0
10.0
2.5
None
0.25
0.375
0.5
81
81
81
81
16
16
16
16
3.76
0.173
0.043
0.023
16248%
652%
87%
163.5
7.5
1.9
None
0.25
0.375
0.5
102
102
102
102
2
2
2
2
0.91
0.063
0.017
0.01
9000%
530%
70%
91.0
6.3
1.7
None
0.25
0.375
0.5
102
102
102
102
4
4
4
4
1.88
0.137
0.037
0.025
7420%
448%
48%
75.2
5.5
1.5
None
0.25
0.375
0.5
102
102
102
102
8
8
8
8
3.81
0.283
0.093
0.048
7838%
490%
94%
79.4
5.9
1.9
None
0.25
0.375
0.5
125
125
125
125
1
1
1
1
0.79
0.67
0.13
0.03
2533%
2133%
333%
26.3
22.3
4.3
None
0.25
0.375
0.5
125
125
125
125
2
2
2
2
1.61
0.157
0.053
0.04
3925%
293%
33%
40.3
3.9
1.3
None
0.25
0.375
0.5
125
125
125
125
4
4
4
4
3.29
0.34
0.14
0.067
4810%
407%
109%
49.1
5.1
2.1
The abdomen phantom is on top of 6 inches
of polyethylene to simulate a 250 lb patient.
The roller shield has a .5mm lead.
18
Comparison of Lead Apron Protection
This yellow apron is .25mm.
Distance Thickness
(ft)
(mm)
0.5
2
0.25
0.5
3
0.25
0.5
4
0.25
0.5
5
0.25
0.5
6
0.25
0.5
2
0.25
0.5
3
0.25
0.5
4
0.25
0.5
5
0.25
Angle
(deg)
90
90
90
90
90
90
90
90
90
90
60
60
60
60
60
60
60
60
Dose
(mR)
0.012
1.595
0
0.834
0
0.546
0
0.338
0
0
0
1.057
0
0.62
0
0.389
0
0
The cumulative dose through a lead apron during
1 minute of fluoroscopy at various distances. A
phantom is supine with 6 in of polyethylene blocks
under it. In room flouro II is 4in above midline of
phantom. The ion chamber records measurements
perpendicular (90 deg) to the migsagittal plane of
the phantom and 60 degrees off of perpendicular.
Facial Bones – Caldwell - Depending on what
Headwork
you call the bottom of the face will change your
entrance or exit point (I like to see the mentum).
Although the literature says the nasion is the
proper exit point, mid nose down to acanthion
really is closer to the middle of the face.
If you want to get the entire mandible on,
this is what it will look like.
19
Many radiographers prefer to get from the top of
the orbits to the cut of the mouth.
X-Table Oblique Mandible – Patient on
rectangle sponge. Head tilted 15-20 degrees.
Cassette (generally non gridded) and tube are parallel
and approximately 30-35 degrees to table.
Perfectly positioned x-table oblique
mandible image.
Upright Oblique Mandible – Tube angled 15-
Coning from meatus to nose, top of ear to
just below bottom of mandible.
20 cephalad. Head tilted 15 degrees. You can
also use rotation for mentum or body.
20
Nicely done upright oblique image.
PA Mandible – OML, Exit at acanthion. Top of
light at top of ear, bottom just below mentum.
Just a classic shot cuz it looks like he has an
elongated head with 4 ears.
Perfect PA mandible image.
Townes View For Mandible – Do not mix this
Very nice Townes view for mandible. Note that
body of mandible is superimposed over spine.
This view is really just for the ramus.
up with a Townes view for a skull!! Top of light
to TEA.
21
Caldwell For Sinus Series – Always cone and
mark it first, regardless of what view you start
with.
Lateral Sinus – Top of light to mid forehead,
Well done Caldwell. Orbits are 1/3 full.
Should have been coned a bit more on top.
bottom of light to mid lips, back of light to
meatus and front of light to mid nose.
To properly rotate the skull/facial bones/mandible
into a lateral position: Begin by having patient PA
and turn head as far as they can without straining.
Keeping head, neck and torso in alignment,
start rotating the patient’s entire body
towards the lateral position.
Keep rotating the body until the skull is lateral.
Their will be some OID that is unavoidable, but
the patient will easily be able to hold this position.
22
Well coned and positioned lateral sinus
image.
Waters View – MentoMeatal Line is same as
AP Waters – If patient is unable to extend
This way you just extend chin as high as they can
go, then lean the patient back until you have the
MML correct.
Perfect MML to get the petrous ridges just
below the maxillary sinuses.
Patient is a little rotated to the right (RPO), a
little tilted to the right, but the main problem is
the chin is not tilted enough (“under watered”).
their chin enough for a proper PA Waters
view, you can always do an AP projection.
putting the TEA just below the bottom of the
cheek bone (maxillary sinus).
23
Obviously off centered with a slight tilt.
Main problem is the chin is over tilted
(“over watered”).
Zygomatic Arch – Modified SMV view.
Tube is on patient’s chest at 28-30”. OML is
basically parallel with the tube and the cassette.
Place the cassette or detector against a small
10-12 degree sponge leaning on a 45 degree
sponge.
To “cheat” the shot, stay centered to the patient’s
mentum and tilt (not rotate) the top of the head 34 degrees away from the affected arch.
Slightly cheating the shot will open up this
patient’s left arch but will pretty much disappear
the right arch.
Here is a perfectly done “cheated” one
side only arch shot.
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Thorax
How much does a scapula move? In this
true AP the scapular body is parallel with the IR.
True AP scapula.
Patient PA and shoulder/scapula rolled
forward (like a PA chest). Scapula is
approxiamately 30 oblique from PA.
Scapula rolled forward approx. 30 degrees.
Patient still PA but with arm
completely brought across chest.
Scapula is approximately 60 degrees oblique.
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Scapula approximately 60 degree oblique.
Patient’s body only needs to be
rotated approximately 30 degrees.
Patient’s body rotated
approximately 30 degrees.
Lateral Scapula - Patient straight PA with
shoulders rolled forward. Scapulas are
approximately 30 degrees rotated.
With arm brought all the across chest, scapula is
now rotated approximately 60 degrees.
Patient should only need to be rotated
about 30 degrees.
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Perfect lateral scapula image.
Sternum – First get light field set-up by
finding manubrium and xiphoid.
RAO Sternum – Shallow oblique of 20 degrees
only. Center sternum to midline of bucky.
Never believe the light field. It will always
look incorrect.
Nicely seen RAO sternum.
This is Billy – he lives in this closet.
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The posterior ribs are thicker and less curved. Even
though on the PA view the anterior ribs are closest to
the bucky, the posterior ribs will always show up better.
AP Upper Ribs – Often done at 72” to get
AP ribs top to bottom. You never know how
good it’s going to be under the diaphram.
LPO Upper Ribs – The spine is rotating away,
This view splays out the posterior ribs and
foreshortens the anterior ribs.
entire unilateral rib cage top to bottom.
so you can’t just collimate to the sternum.
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LPO looking good
RPO Upper Ribs – The spine is now into the
ribs, so the sternum is the most lateral point.
The posterior ribs are foreshortened and the anterior
ribs are elongated. Note that the anterior ribs actually
go across the spine.
RPO, at CHOMP this is a tangential view for
the lateral border.
AP Lower Ribs - All you need is diaphram to
crest and midline to lateral border. Remember
that this is always taken on expiration.
This is what it should look like.
29
PA Upper Ribs – Again it’s always good to
The perfect PA. Sometimes air in the
stomach or the colon can really help you out.
RAO Upper Ribs – Get spine to lateral
border.
Anterior ribs foreshortened, posterior ribs
elongated.
RAO, posterior ribs perfectly splayed out (even
though they are further from the bucky).
LAO Upper Ribs – Remember that
sternum is now more anterior than spine.
get the lower ribs on if possible.
30
Posterior ribs now foreshortened, anterior ribs
elongated. Note anterior ribs have again come
across the spine.
LAO, you can’t get a better view of those
anterior ribs than this.
Using hands to simulate the rib cage and spine
The bent fingers are the ribs and the thumbs are
the spine. By turning the hand you can see if the
spine will be in the ribs on that view.
PCXR’S

Let’s start with what locks actually control
what movements.
This first section explains the locks on
an AMX portable. If you are not
using this brand, the locks will still be
comparable.
The Main Handle Clicker (Clicker) controls
the vertical (up and down) lock.
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It also controls the in and out.
The floor to ceiling rotation of the tube itself does
not use anything but friction to move and hold
itself in place.
All of the following tube height's and angles
start with the top of bed being 28-29” from
the floor.
Lastly, it controls the side to side sweep (known
as wag on a C-arm).
The side to side rotation of the tube also is just a
friction “lock”.
So now we get to the crux of the whole
thing: How much do you angle the
tube? This will of course depend on
how much the patient is sitting up.
The most important thing to note is
that the angle of the patient really is
the angle of their sternum, not the
cassette or the patient’s spine.
32
For any given patient’s (sternal) angle,
there is only one perfect height for the
tube. At this height you will now get
the perfect down angle for the tube.
The next set of slides will have to do
with how high you put the tube. The
numbers on the tower refer to how
high the top of the main arm is below
or above the top of the tower.
This patient is at 50 degrees. The bed is about
10 degrees from max up and there is no pillow
behind the cassette. This is the least erect a
patient can be and still shoot at 72.”
The bed is all the way up. With no pillow behind
the cassette, the patient is at 60 degrees. The
tube arm is 1” below the top.
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With the bed all the way up and a pillow behind
the cassette (and the patient not pushing back
against it), this patient is at 70 degrees. The
tube arm is 8” below the top.
9 out of 10 AP chests can be done at 70 degrees.
Another way to gauge this height is to keep the
collimator pointing towards the floor and measure
yourself to it. Here my eyes comes to the space
between the swinging arm and the tube head.
This patient has two pillows behind the cassette
and is sitting almost straight up. The patient is
at 80 degrees. The tube arm is 15” below the
top.
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This patient is kyphotic. The cassette is straight
vertical and the patient’s sternum is at vertical.
The tube arm is down and parallel with the floor.
Almost all patients are down in the
bed. This means that probably 95 out
of 100 patients will need to be pulled
up to the top of the bed before you sit
them up. Your goal is to pull them up
until the top of their head is even with
the top of the bed.
When you come into the room, leave the patient
where they are until you are ready to put the
cassette behind them. The following things
should be done first.
Bring the portable in as parallel with the bed as
possible, putting the edge about 5-6” away.
Park the portable so that the front edge of the tower
is even with the bottom of the bed. This works
perfectly if the pt. is up about 20-30 degrees.
Swing the arm out 90 degrees, pull it out until it
is basically even with the center of the patient
and put about a 70-80 degree angle on the tube.
35
With the marked cassette in a pillowcase you are
now ready to sit the patient all the way up. Lean
the patient forward placing the cassette with a
pillow behind it. Next check cassette placement.
After checking that you have ½”-1” of cassette
above the top of the shoulders and the shoulders are
the same distance from the edges, check that the
lateral borders of the rib cage are also the same
distance from the edge of the cassette.
The best way to do this lower check is to put
your palm against their ribcage and slide your
fingertips laterally. They should fall off the
cassette at the same time.
Once you have determined what angle your patient
is up at, make sure the tube is at the approximate
angle and then use the clicker to put it at the exact
height. She is 5’3” so the lower knob is even with
her nose.
Next step is to check the distance. If you can’t reach
the 72”, keep holding the end of the tape measure (but
bring it away from the cassette) and with the other hand
push the clicker and move the tube to the correct place.
This way you only have to move 6” or so to touch the
cassette and double check the distance.
If your arms are long enough, hold the tape
measure against the cassette and just push the
clicker and move the tube until you have your 72”.
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Now it is time to get the tube head parallel with
the bottom of the bed (which is parallel with the
cassette). I use the trapeze bar since it is easy
to see than the cassette.
Remember that this tube head move does not
use the clicker.
I like to move the tube head by gripping the
metal U with my fingers and putting my thumbs
below the collimator knobs. This way you can
make tiny, precise movements.
Now it is time to get the exact angle of the tube
(ceiling to floor). Since the tube head is already at
the perfect height, angle it with one hand on the U
and the other holding the tube. No clicker needed.
Since you won’t be perfectly lined up side to side,
click the clicker and…
move the tube to center on the sternum.
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Make sure that you can see where the bottom of
your light is at, otherwise it is very easy to have
light below the bottom of the cassette.
If you don't have the portable in the correct place
then the tube arm will not be parallel with the
cassette.
This means as you move the tube in and out you
will be changing the distance away from your
patient.
How to keep from ever having a
double exposure
The goal is to have the top of the third rib just
showing over the top of the clavicle.
You have to put your
paper on the exposed side
of the cassette and tape it.
If you put it on this side of
the cassette you might
never see it
Spines
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AP C-Spine – “Mustache-Meatal” line
perpendicular. 15 degree cephalad beam. 8x10
field. Top of light to midline point between lips.
Trauma Oblique C-Spine - Move patient until
edge of cassette is even with edge of neck. Do
not use a grid.
Keeping the tube at this height, put a 45 degree
angle on it. Move the tube side to side and head
to feet with the collimation light on to center the
tube properly.
Perfect AP C-Spine. Note that the base of the
skull and the mandible need to be superimposed.
Make sure tube is at 40” detente height.
You will probably end up at around 50”.
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The light should go from top of ear to just
above the xiphoid and skimming both anterior
and posterior neck (which is difficult to see
because of the collar).
This is basically what it will look like. This is our
c-spine/skull phantom so that’s why it looks
strange at C-7.
This is the towel trick to have a patient pull their
own shoulders down for a x-table lateral c-spine.
Make sure towel is tight at this point.
Shoulders will be pulled down once the
patient extends their legs.
How to properly check a patient for scoliosis
before you lie them down for a T-Spine.
AP T-Spine – Always pre-collimate to 6”.
It will look small, especially on large patients.
40
Use the numbers, not the looks of the light.
Even with a little scoliosis you
can easily fit the patient in 6 inches.
When you only collimate to 9” you will always
have too much scatter coming through the lungs,
causing an underexposure if using an AEC.
3 fingers in from the ASIS and 2 fingers above
the crest works perfectly with 45 degrees.
Here is what 9 inches looks like. Note light
is noticeably wider than width of neck.
– Perfectly rotated to 45
degrees.
Oblique L-Spine
You can always double check by feeling the
spinous process.
41
It’s all about the Scotty dogs. Here is
another exam where you should pre cone to
about 8” x 14”.
If oblique is too steep you will know it because 2
fingers in from ASIS will be centered.
When oblique is too steep the ear of the “Scotty
Dog” will be past the halfway point.
If oblique is too shallow you will need 4
fingers to center over the spine.
This oblique is too shallow. Note that the “Scotty
Dog” ear is not even at the ½ way point.
Lateral T-Spine – T1-T3 is not that important.
You have to get on T11-T12. You can feel the
crest (which is L4), the fade down to the spine
and count up to T12-L1.
42
Perfect lateral T-spine showing T3 – T12.
T/L Junction –1/2-1” above point in-between
xiphoid (T10) and crest (L4).
T3
T 12
Well centered (and badly coned side to side)
T/L Junction image.
Beautifully centered T/L Junction image. Quite
often it will turn into a technique problem.
Lateral T/L Junction – You can count up from
crest and/or use the distance above crest that
you used for the AP. It’s pretty tough to use the
xiphoid when the patient is in this position.
Portable, Double Shot
& Decub Abdomen
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With patient still in comfortable position,
measure out your 40”.
Next, get the tube parallel side to side.
Then get it parallel front to back (it always
helps to squint).
If you need another person to assist you, push
the machine to the end of the bed to give both of
you plenty of room to move.
Take the grided cassette in the pillowcase and
mark the crest. Roll the patient up and get the
cassette under the patient as much as possible.
After centering the patient onto the grid side to
side, mark both the top and bottom of the
cassette with your hands. This is the easiest way
to see where the light should be centered.
44
Nice shot. Obviously with this technique he
wasn’t shooting for that contrast.
This is what the images look like. You’ll
usually get Pubic Symphysis to diaphragm
but will miss quite a bit laterally
This is what it will look like
This is the way most techs shoot an abdomen
using two 14x17’s. Crosswise, one on top of
the other with overlap in the middle
On patients that aren’t too tall but are pretty wide,
quite often you will be better off taking 2 lengthwise
side by side views over top and bottom shots
Decub Abdomen - Always do this view with the
patient AP. That way you can easily move them
all the way back against the bucky.
45
AP decub abdomen, very nicely done. If you
mark the right side, you need to annotate the
left lateral decub on the left side.
Here is why you should never do an abdomen
decub PA. It is always more difficult to get their
abdomen close to the bucky, and their arms and
knees get in the way.
Left
Lateral
decub
PA decub abd. Remember you always need to
get the right diaphragm on.
AP Thumb – This is perfect body and hand
positioning.
Upper Extremities
Many times a patient cannot get the matacarpals
from being superimposed.
46
Pretty good AP thumb positioning. Note
proximal metacarpal is partially covered.
Perfect externally rotated AP thumb.
See that thumb will not be touching the
cassette.
Proper body and hand positioning for
externally rotated AP thumb.
PA Thumb – note that cassette is on top of a
sponge and that the thumb needs to be brought
over ¾” from the edge.
Perfect PA thumb image.
47
Oblique Thumb – perfect positioning.
Perfect oblique thumb image.
Too Steep Oblique Thumb - You can’t just put
their hand down for the oblique and expect it to
be perfectly positioned.
This is an oblique thumb that is too steep.
You will see this happen a lot if you just
take what you get.
Long PA Wrist – Centering just proximal to
Perfect long PA wrist.
styloid process. Show one-third to one-half
of forearm.
48
Short PA Wrist – Centered on styloid
process.
Although I almost never do it, this one time I
shot a short wrist on a 15 year old because he
could easily move the wrist around.
Lateral Elbow – Not exactly centered over
condyles has least amount of scatter.
Classic 4 on 1 short wrist images.
Because of the little density he saw on the
lateral, he had me shoot a forearm.
Concentric condyle circles still look good.
49
Lateral Elbow – Centered exactly over the
condyles will have more scatter.
Concentric condyle circles are perfect.
Possible way to block off excess scatter.
Correctly Rotated Internal Elbow – 45
degrees, entire arm rotated from the shoulder.
Here is a perfect internally obliqued
elbow.
Arm was rotated from the wrist. This way
elbow may be too flat or steep.
Incorrectly Rotated Internal Elbow –
50
This elbow ended up getting over
rotated.
Lateral Humerus – Humerus horizontal, elbow
bent 90 degrees, wrist lateral with thumb down.
The shoulder girdle is always going to be
lighter and the condyles of the elbow will
never be superimposed, but this is an easy
way to do a lateral humerus that is more
comfortable for the patient.
PA Scapular Y – Humerus vertical, body rotated
You can either gauge the 45 degree angle
across the chest or back.
AP Scapular Y – Humerus vertical, body rotated 45
45 degrees. Exit at mid humerus side to side.
degrees, centered side to side at middle of humerus.
51
Perfect Mercedes image. Note that humerus is
directly superimposed over body of the scapula.
Rotate head away and bring cassette against
neck. Tube angle is 25-30 degrees. If arm
abducted less than 90 degrees, tube angle 15-20.
Standing Axillary shoulder - This is the
new view we are using at our off site
facilities that don’t have CR or movable DR
detectors.
Axillary View – Bring pt. to edge of table, arm
resting on hamper with pillow, cassette between
shoulder and pillow, arm externally rotated.
Well centered and collimated Axillary shoulder image.
Humerus needs to be level with floor to be perfect.
Patient is perfectly AP.
Bring the arm up on top
of the head.
It’s nice to get the
humerus as vertical as
possible but it’s not that
important.
Center to the soft spot
which is right about at
the acromion.
52
Here are comparison views of the new axillary
view (a Left) versus the x-table (of the Right) on
the same patient (her arm was really hurting).
So I ended up needing a shoulder series.
My arm is as high as possible, hand pointing
straight ahead with a 15-30 cephalad angle.
The angle depends on how much of the Glenoid
Cavity superimposes the humeral head. The
more the superimposition, the more you angle.
The image on the left is my shoulder with a 20
degree cephalad angle. The image on the right
is a normal x-table axillary lateral.
This is Lito’s AP shoulder. Again you can see that
there is a good amount of imposition, so we will
angle 25 degrees cephalad.
Here you can see that he cannot bring his arm
straight up. That doesn’t seem to matter very
much. You can still get a lateral Glenoid Fossa
shot with the right angle.
53
AP ankle - centered proximal of
malleolus.
Lower Extremities
AP ankle - foot needs to be flexed to
90 degrees.
This is what happens if you center on the joint
and still want to show a fair amount of tib-fib.
AP ankle
-
Centered above the malleolus. This
is a classic long ankle.
Big toe - use stretchy 1” tape. Tape all
four toes as one unit.
54
Tape big toe separately, then put foot
lateral. Have both tapes extra long. You
don’t need to have the big toe down.
First pull tape with four toes as tight as
possible, making sure that toes are bending.
Then pull big toe tape as much as patient
can handle it.
Big toe taped and viewed from above.
Perfect lateral great toe.
Middle toe - Using 1” stretchy tape, wrap
first and second toes and fourth and fifth
toes together.
Get foot in lateral position with middle toe
centered. Pull both sets of tape tight at the
same time.
55
Middle toe ready to go, viewed from above.
Bilateral Prone Sunrise (Hughston
View)- Tube is a minimum of 45 degrees.
Distance is around 35”. You need to rest
the toes on the collimator.
Bilateral Sunrise – Patient prone, DR
Second toe did not quite get out of the way, but
still a very nice lateral middle toe.
Have legs together with no rotation. Center
between legs and just anterior to apex of patella.
Tangential “Sunrise” View
done in a wheelchair
positioning
56
Patient sits in wheelchair with feet flat
on floor and patella touching the bucky.





Here are 2 different patients’ images
The bucky is angled back
15 degrees.
The tube is angled 15
degrees from vertical.
Femur will be flexed 15
deg. to match the bucky.
Center to top of patella.
Make sure grid is out of
bucky.
X-Table lateral knee - knee put on towel
which has been quartered and rolled.
Make sure knee is perfectly AP, center tube
¾” below patella with no cephalad or caudal
angle on tube.
You need to have the femur absolutely
parallel with the edge of the table.
X-Table lateral knee
57
Lateral Femur into bucky - Patient is perfectly
lateral with top leg bent and put on cushion or
pillow. Body needs to remain lateral.
Lateral Femur into bucky - Note that
malleolus cannot be superimposed top to bottom.
X-Table Lateral Distal Femur - Similar to
X-Table lateral femur - hard to have a good
X-table Lateral Hip – Affected leg straight
down table. Tube and grid at 45 degrees. Grid
all the way up to 9th-10th ribs.
Good knee bent and rolled out with foot on
tube (note towel under foot).
x-table lateral knee.
technique for both distal and proximal ends.
58
See that the unaffected leg is completely out of
the way. This will only occur when the
unaffected leg is rolled out.
Note that half of the light field is the unaffected
sides buttocks. Need to use the Ferlic Filter.
Using a DR detector and a mobile table – Only
able to bring patient out 25-30 degrees.
Having patient hold up their own leg.
Using the DR detector and the Ferlic Filter.
59
Here are 4 different Ferlic Filters.
Swimmers and x-table hip, Lateral C-spine,
X- table lateral L-spine and AP T-spines
Down while positioning the tube for the
Lateral C-spine (x-table or standing)
Then just slip it up to shoot.
It stays in place with a magnet.
60

“Sliders” bags. Comes in 2 sizes.
One for DR detector and grid,
the other for CR cassette and grid.
Anchor-leg stabilizer
Information On the Ferlic Filter
Radiographic Image Analysis
by Kathy McQuillen Martensen
Ferlic Filter Co. LLC
4770 White Bear Parkway
White Bear, MN 55110
Phone: 877-429-9329
Fax: (651)846-5745
Email: dan@ferlicfilter.com
Third
Edition
Dennis Bowman R.T.(R)
Radiographer/Clinical Instructor
Community Hospital of the Monterey Peninsula
Work (831) 625-4830, ext. 4335
Fax (831) 625-4784
dennis.bowman@chomp.org
61