This is a overview of the devices used in the radiotherapy planning. These are specifically designed for patient proper positioning, reproducibility and immobilization of patient during radiotherapy treatment.
2. Patient positioning, fixation and
reproducibility of setup
• Whether you are doing conventional radiotherapy, 3D
conformal or IMRT treatments – accurate,
reproducible positioning and rigid fixation are
important factors for precise dose delivery to the
treatment portals.
• Thermoplastic shells offers a reliable method for
accurate positioning and immobilization.
• There are three essential components required for
making these shells. (i) Base plate: made up of
acrylic material or carbon fibre. Available for head
and neck cases, chest, pelvic regions. (ii) Neck
supports: foam type poly urethane material or silver
man standard supports. (iii) Thermoplastic masks.
3. What is
patient immobilization?
a reproducible localization of the patient with a device
into which the patient is locked, to aid in the restriction
of anatomical movement
4. Why use positioning and
immobilization devices?
increase target accuracy
easy to use
quick to set up
comfortable for the patient
durable enough to withstand an entire course of treatment
5. What is patient
positioning?
a reproducible localization of the patient with the use of
a device onto which a patient lays a specific part of
their anatomy
designed to guide the patient into the original
simulation position for radiation beam administration
6. History of patient positioning
sand bags
tape
bite block
plaster casts
“home-made devices”
9. Consistency
Consistency in patient positioning and immobilization
from treatment planning to simulation, and from
simulation to treatment must be maintained.
Differences in table/couch geometry, “tennis-racket”
sag and mechanical wear of simulator/accelerator,
must be kept to an absolute minimum.
10.
11. verbal statements to
immobilize patients
1. ONLY INVOLUNTARY MOVEMENTS, PLEASE.
2. HOLD VERY, VERY STILL.
3. LIE QUIET
4. BE MOTIONLESS.
5. LET A CALM FALL UPON YOU.
6. NO MOVEMENTS, PLEASE.
7. PLEASE DO NOT MOVE.
8. DON’T WIGGLE, NOW.
9. LAY HEAVY, BECOME AS ONE WITH THE TABLE.
13. Challenges of
the head and neck region
neck extension must be controlled
claustrophobic patients
inserting bite blocks or shunts in a
thermoplastic mask
reproducibility of daily setup
14. Current methods for
positioning and immobilization
thermoplastic mask of the head
thermoplastic mask of the head and
shoulders
treatment chair
positioning aids
16. Thermoplastic masks
thin sheets (usually 1.6mm to 3.2mm) of solid or
perforated plastic sheets bonded to a rigid frame
water temperatures for perforated thermoplastic must
be 165oF
17.
18.
19.
20.
21. Top 10 Uni-frame® tips
Set up your warming pan with 2”-3” of water and heat
to 165° F. Use a digital thermometer to check the water
temperature. Do not overheat.
Place the baseplate on the treatment table with the
appropriate head and neck support.
Apply a light coating of baby oil or other lubricant to the
side of the mask that will contact the patient’s face to
keep thermoplastic from sticking to skin, hair and head
rest; apply to entire surface.
22. Top 10 Uni-frame® tips
Place the Uni-frame into heated water , until
thermoplastic turns clear (1-3 minutes).
Remove Uni-frame from water and shake excess
water from holes; this should be done quickly, before
mask begins to harden.
Center the Uni-frame over the patient’s face; starting
under the chin, gently pull the mask toward you over
the face and head and down to the baseplate. Align
holes in the frame to pins in the baseplate; lock clamps
to frame.
23. Top 10 Uni-frame® tips
Gently mold soft thermoplastic material to patient’s
facial contours (eyes, nose, cheeks, etc.) to form a
mask. Total working time is 2-5 minutes.
As the thermoplastic cools, it returns to its original
white color and becomes rigid. Allow to cool
completely! Removing the mask too soon will cause
additional shrinkage, and a too-tight refit.
If desired, the thermoplastic can be cut to create
treatment portals after the mask has hardened. Cut
with a cast cutter
24. The question mark
technique
Stand behind your patient’s head, position the
edge of the thermoplastic approximately 1.5
to 2” under the patient’s chin.
25. The question mark
technique
Begin by catching the patient’s chin
approximately 1.5” inches into the
thermoplastic mesh. Gently pull the Uni-
frame eight to ten inches in the superior
direction, just above the patient’s nose.
27. The question mark
technique
Pull the thermoplastic down and onto the
black indexing pins of the baseplate. Lock the
Uni-frame to the baseplate with the quick-
release locks.
28. The question mark
technique
Reach under the mesh at the patient’s throat
and “flair” the mesh out about 90o away from
the patient’s throat to create a smooth. Apply
the three finger pinch at the bridge of the
nose. Mold the mesh against the nose and
face to replicate the contours of the face for
30 to 45 seconds. Allow the mask to harden.
30. Head and shoulder
thermoplastic mask
designed to provide maximum head
and upper body fixation by capturing
the head, neck, and shoulders under a
continuous thermoplastic sheet
31.
32.
33. Benefits of thermoplastic masks
economical
disposable
can re-use PVC frame (with re-loadable systems)
markers can be placed on the mask rather than the
patient
reproducible positioning is achieved
35. Treatment chair
comfortable, reproducible positioning for patients who require
vertical positioning
accurate positioning for claustrophobic patients
reclining back that adjusts to six positive-locking positions
36.
37. Benefits of the treatment chair
can accurately re-position claustrophobic patients
can choose “arms-up” or “arms-down”
can use thermoplastic mask or thermoplastic bra support options
38. Limitations
of the treatment chair
large device may be difficult to store
there isn’t a large percentage of patients who will require this type
of positioning
51. Wingboard
polycarbonate material with head and
arm rests
designed to fit through CT scanner,
used for both treatment and diagnostic
imaging procedures of the thorax,
breast and lung
52.
53. Benefits of wingboards
patient can rest arms and elbows
comfortably
designed to fit through CT scanners
can be indexed to various breastboards
55. Breastboards
primarily used to elevate the patient’s
upper torso above the treatment couch
to bring the sternum parallel to the table
creates a uniform surface dose
distribution across the treatment area
62. Treatment brassiere
plastic material
attenuation factors similar to a Silverman
reshapes the ipsilateral breast
reproducible setups
reshapes the contralteral breast to
move it away from the beam
63.
64. Benefits of the
treatment brassiere
reduced dose to lungs, heart and ribs
shape and position are reproducible
All sizes of cup sizes are available
eliminates mammary folds
marks can be made on the device and/or
patient for re-alignment
66. Lungboards
Primarily used to for lung treatment,
however, it can be used for other
treatments where immobilization of the
upper torso and arms-up positioning is
required.
67.
68. Benefits of
breastboards and lungboards
brings the sternum parallel to the table.
simplifies treatment set-ups
eliminates skin folds
73. Benefits of vacuum cushions
cost-effective
re-usable
quick to set up
full range of sizes
treatment portals are available
safe to set up
longevity is dependent on care and use
74. Limitations of vacuum cushions
vacuum or wall suction is required
storage space is required
may puncture or develop leaks
can not “cut-away” into the cushion
77. Thermoplastic positioning
thin sheets (usually 1.6mm to 3.2mm) of
solid or perforated plastic sheets
cross linked linear polyester softens in
warm water
water temperature for solid
thermoplastic must be 150oF
water temperatures for perforated
thermoplastic can range from 160oF
to 170oF
85. Benefits of thermoplastic
positioning devices
can be used with prone or supine treatments
exact cast negative of patient anatomy provides
precise reproducibility
marks can be made on the thermoplastic rather than
the patient
portals can be cut out of the thermoplastic
can be integrated with vacuum cushions for
increased comfort and accuracy
86. Limitations of
thermoplastic immobilization
thermoplastic sheets are expensive
technique sensitive application requires
hands-on training by vendor
must have a large water bath