Immobilization Flashcards
➤ Incapable of movement
> is used to make sure the patient stays in the treatment position during the course of treatment.
IMMOBILIZATION
Patient ___ and ____ are said to be the most crucial part of Radiation therapy treatment.
positioning
immobilization
Immobilization such as __,___,___ and other devices are constructed to reduce set up errors and patient movement during treatment.
moulds, casts, head rest
most common immobilization device used to treat cancers is
Available in different sizes and shapes
> It is rigid in room temperature. When it heated in water for temperature _ to _
degree) the material softens and become malleable. > When it is wet, it is placed over the patient body an conforms to the contour of the treatment area.
Thermoplastic
60-65 deg celcius
Types of immobilization
Head & neck immobilization.
Immobilization in Brain tumors.
Thorax and Breast immobilization
Pelvic and abdominal immobilization. Immobilization for the Body extremities.
Initial construction and selection of proper immobilization for H&N cancer is one of the most important parts of confirming proper treatment of the patient.
> Current methods for the H&N tumors include a variety of masks molds, and frame systems. In some instances,
HEAD AND NECK IMMOBILIZATION
are used to pull tie Shoulders out of the treatment field for the neck.
shoulder Retractors
> plate onto which the head immobilization system is securol
is referred to as a Base plate. It is usually made of __or __.
It should be low z material and should attenuate the radiation minimal when the beam passes trough it.
FIXATION BASE PLATE FOR HEAD AND NECK
Perspex carbon fiber
For the General brain tumor and whole brain cases the mostly common immobilization device is the 3 clamp
BRAIN TUMOR IMMOBILIZATION
-
Patient Head positioned with the chin Hyper extended to include the superior extent of maxillary antrum in the anterior field without including the eye.
Maxillary antrum Tumors
- Head positioned with neck in extreme flexion
Anterior beam can avoid the dose-limiting structures such as the optic chasm, the retina and much of the brain tissue
Pituitary or small brain Tumors
There are 3 common immobilization
Devices used when treating the tumors in the chest cavity,
Voclock
Breastboard
2 clamp or 4 clamp thoracic mould
3 THORAX AND BREAST IMMOBILIZATION
VACLOK.
BREAST BOARD.
2CALMP OR 4CLAMP THORACIC MOULD
Consists of light weight plastic mattress filled with radiolucent polystyrene (Styrofoam) heads
The air is then vacuumed out of the bag for a custom fit and scaled in order to retain the shape
VACLOK
Advantage- of voclok
■_____after treatment the bag is recycle and used for other
Radio translucent,
- It is used specifically for the treatment of breast cancer It has several ad unstable features to allow for the manipulation of patient arms, wrists, head and shoulders.
Allows the patient to be positioned with the chest wall horizontal avoiding angulation of the collimator
.
BREAST BOARD
Breast boards are generally constructed of ____allowing the device to be light weight and durable
carbon fiber, thermocol
d Carbon fiber breast boards have ___attenuation levels, which permit maximum beam penetration.
- Takes advantages of gravity to pull the large breast down into better treatment position
Lower
➤ are used when the patient is treated in prone position, it is allow the small bowl to drop below the lateral field to avoid severe side effect
minimizes the average volume of Small bowel that would otherwise be within the lateral field during the standard box field technique treatment.
BELLYBOARD IMMOBILIZATION
There are two important aspects to be followed in the case of Pelvic Immobilization.
➤ Properly maintain patients outer contour during treatment with respect to the isocenter. ➤ Other is related to the variation of internal structures During the daily treatment,
PELVIC AND CHEST IMMOBILIZATION
IMMOBILIZATION FOR EXTREMITIES
> Immobilization for the body Extremities is a quite challenge for Us But with this special _____solution we can perform it easily.
> The system consists of a low density carbon fiber base plate with a leg support, two comfort cushions and dedicate masks. The base plate can be indexed to any couch top on
2-pin bars and has multiple holes to offer a maximum of possibilities for positioning and immobilizing both upper and lower extremities.
thermoplastic
6 immobilization for extremities
Head rests &wedges
Indexing bar
Knee rest & foot rest
Oral prosthesis or mouth bite
Alpha cradle
Alignment marks
➤ The two pin ____ is designed for reproducible positioning and stable fixation of the base plate. > can be placed at the desired indexing
indents the couch and can be locked.
INDEXING BAR
> Used to maintain the patient position during pelvis irradiation.
It avoids patient tilt (Rotational error)
KNEE REST AND FOOT REST
➤ Helps in reproducing the opening of the mouth during the treatment.
➤ used to minimize the volume of oral mucosa within the treatment field. The patients mouth kept open by inserting a mouth bite made from dental impression material.
ORAL PROSTHESIS OR MOUTH BITE
which helps to maintain the position without strain > The curvature of the patient cervical spine can be altered by
changing the support under the head. ➤
HEAD RESTS & WEDGES
Materials Used:
Acrylic/Rubber Polyurethane.
> Two-part chemical foaming agents are mixed together, initiating the chemical reaction that causes Polyurethane foam to expand.
> The mixed foaming agent is distributed evenly throughout the body form and sealed inside the polyvinyl bag. Patient is positioned in the treatment position on top of a polyvinyl bag as the foaming agent expands _to _min
ALPHA CRADLE 10 -15
➤ External marks placed on either the patient’s skin or the immobilization devices ➤ For initial laser alignment as a surrogate for internal target anatomy. > In-room laser system in the simulator suite or Should givecoordinates in 3 dimensions
> Preferably made on the immobilization device as it i morereliable as opposed ti the patient’s skin (soft tissue &mobile). ➤ If on skin, preferably marked on bony landmark for arelatively fixed geometry ➤ Issues - Motion of soft tissue with relation to immobilization device,
Marks washing off, Wearing off or migration.
ALIGNMENT MARKS
, > Immobilization becomes more complex for radiosurgery.
CYberknife and Gamma Knife procedure because the requirements for positional and numerical accuracy for
The dose delivery are- +1mm.
Thermoplastic orfit
Immobilization system such as ____, and ____are
commonly used during treatment of pelvic
region
Voclok belly board
thermoplastic masks
