Radiation prostheses 2/ oral surgery courses

THE RADIATION THERAPY PATIENT ;THE RADIATION THERAPY PATIENT ;
TREATMENT PLANNING & POSTTREATMENT PLANNING & POST
TREATMENT CARETREATMENT CARE
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTSCONTENTS
☻ INTRODUCTION
DEFINITION OF RADIATION THERAPY
INDICATIONS OF RADIATION THERAPY
TYPES OF RADIATION SOURCES IN R.T
MODALITIES OF RADIATION THERAPY
DOSIMETRY
 TYPES OF RADIATION PROSTHESES
 SOME TECHNIQUES OF FABRICATION
 REFERENCES
 CONCLUSION

INTRODUCTIONINTRODUCTION
 Radiation therapy has been used with increasing
frequency in the recent years for the management of
neoplams of head and neck region.
 A majority of patients with such tumors will receive
radiotherapy at some time during the course of their
treatment...In some tumours it is preferred treatment,
where as in others it is employed in combination with
surgery or sometimes with chemotherapy.

WHAT IS RADIATIONWHAT IS RADIATION
THERAPYTHERAPY ??
According to JOHN BEUMER AND THOMAS A.CURTIS,
Radiation therapy is defined as” the therapeutic use of
ionizing radiation in the management of neoplasms of the body
without surgery or as an adjunctive palliative treatment after
surgery, either in combination with or with out chemotherapy”.

Treatment (NEED) for Head andTreatment (NEED) for Head and
Neck CancerNeck Cancer
• Surgery, radiation therapy and chemotherapy are the
mainstays of treating head and neck cancer.
• For many head and neck cancers, combining two or
three types of treatments may be most effective

 An important concept in treating head and neck
cancer is organ preservationorgan preservation. Rather than relying on
major surgery, an organ preservation approach first
uses radiation and chemotherapy to shrink the
tumor.
 This allows for a less extensive surgery and may
even allow some patients to avoid surgery
altogether.

INDICATIONS OF RADIOTHERAPYINDICATIONS OF RADIOTHERAPY
IN HEAD AND NECK LESIONSIN HEAD AND NECK LESIONS
1. Squamous cell carcinomas of soft
palate, floor of mouth, tongue, lips
and buccal mucosa
2. Adenocarcinomas of salivary and
mucous glands
3. Primary lymphomas of
nasopharynx, tonsils
4. Carcinomas of maxilla and
mandible
5. Carcinomas of piriform
sinus,subglottic area etc..

WHAT ARE DIFFERENT TYPES OFWHAT ARE DIFFERENT TYPES OF
RADIATIONS USED FORRADIATIONS USED FOR
RADIOTHERAPYRADIOTHERAPY ??
1. ELECTROMAGNETIC WAVES of
wavelengths less than one Armstrong (A0
)
called PHOTONS.
 No mass and no charge
 Ex: x-rays, gamma rays
2. PARTICULATE RADIATIONS
 Have mass and charge
 Ex: electrons, protons, neutrons, alpha
particles , pi-mesons etc..

WHAT ARE THE DIFFERENT TYPES OFWHAT ARE THE DIFFERENT TYPES OF
RADIATION THERAPY MODALITIESRADIATION THERAPY MODALITIES ??
 EXTERNAL
RADIATION THERAPY
 INTERSTITIAL / INTRACAVITARY
RADIATION THERAPY

EXTERNAL RADIATIONEXTERNAL RADIATION
THERAPYTHERAPY
 Most common modality of radiation therapy.
 Also called TELETHERAPY
 Used to deliver high doses of radiation to tumors that
are located with in 6cms of skin surface.
 When external radiotherapy is used the doses are of
order of 6500rads to 7500 rads for 6-7 weeks.

The following energy sources are used for external
radiation therapy
low energy x-rays (50 kev to 100 kev) which are
appropriate for treatment of small and superficial tumors
Orthovoltage (200 kev to 250 Kev), which is convenient
for the treatment of superficial, but thick tumors.
High energy photons (cobalt 60 and high accelerator),
which are used for all deeply located tumors.

INTERSTITIAL RADIATIONINTERSTITIAL RADIATION
THERAPYTHERAPY
Also called BRACHYTHERAPBRACHYTHERAP
Used to deliver high doses of radiation over a short
distance
for a short time period.
Internal radiation therapy involves surgically implanting
radioactive material into a tumor or surrounding tissue

 Used to deliver high doses (up to 20000rads) in a
relatively short time(10-15hrs)
 Uses radioisotopes(Co60,Cs137,Ir 197 ) positioned
in or close to the tumor
 If radiation source is placed in a cavity it is called
Intracavitary source or if it is inserted or implanted
directly into tissue its called interstitial source.

Most commonly used interstitial sources are needles,
narrow tubes, wires or seeds containing radioactive
cesium, cobalt, gold or iridium
Tubes are loaded with
tiny radioactive seeds that
remain in place for one or
several days to kill the cancer.

Branchy therapy disadvantagesBranchy therapy disadvantages
Inhomogeniety of dose throughout the implanted volume
- Hot spot (radioactive source placed too closely together)
- cold spot (radioactive source placed close to each other )
Requires adequate skill & technique
Need of general anesthesia
Potential exposure of the medical personnel

HOW IS RADIATION THERAPYHOW IS RADIATION THERAPY
GIVEN?GIVEN?
• Given in a series of treatments or fractions
called fractionationfractionation..
• Most radiation therapists deliver external
curative radiation therapy for oral tumours in
about 30 fractions, spread over a 6-7 weeks
period.

TISSUE DAMAGE CAN OCCUR EITHERTISSUE DAMAGE CAN OCCUR EITHER
DIRECT INDIRECT
--When sec particles react
with the target molecules
-Target molecules is the DNA
--Interaction with water
to produce free radicals
(HYDROXYL GROUPS)
Nucleus is more sensitive than cytoplasm
Most of the damages are confined to the
intranuclear structures such as DNA & mitotic
apparatus

DOSIMETRYDOSIMETRY
Dosimeter is a device used to calculate the amount
of dosage required for a lesion
RADRAD (RADIATION ABSORBED DOSE)RADIATION ABSORBED DOSE)
It is a unit to measure the amount of energy absorbed by tissues
that are subjected to radiation exposure.
1 RAD means 100 gms of energy is absorbed by I gm of tissue.
ROENTGENROENTGEN
It is the unit to measure the amount of exposure to radiation.
it is based on absorption in air and not by tissues.

MILLICURIEMILLICURIE
• It is the unit of activity of radioactivity material.
• 1 mCi = 3.7 x 107
disintegrations/sec
NSDNSD ( NOMINAL SINGLE DOSE)
The normal tissue tolerance in head and neck has been
in range of 1800 rets (radiation therapeutic equivalents)

RADIATION THERAPY TREATMENTRADIATION THERAPY TREATMENT
PLANNINGPLANNING
1.Complete physical examination, lab studies
& Taking detailed images of patient body
and
2.Marking the precise areas that will receive
the beams of radiation.
3.Positioning the body
whether it should lie on back, stomach or
side.
--A cushion-like device called a Vac-Lok
bag — similar to a beanbag with the air
removed — holds its shape, cradling you in
the optimal position

4.Immobilizing your head
immobilization device used
during radiation therapy is a
thermoplastic mask.
5.Imaging
Once correctly positioned, radiation
therapy team takes images of treatment area.
helps radiation therapist determine the
exact spots where treatment will be focused.

6.Planning
Plan might involve a single beam of
radiation, or it could include multiple
beams.
One may wait several days after
simulation before you begin treatment
7.Treatment begins
During treatment, pt placed on a table in the same position
that as placed in during the radiation simulation.
The positioning or immobilization
devices used in simulation will
now be used during radiation therapy.

WHAT IS RADIATIONWHAT IS RADIATION
PROSTHESIS?PROSTHESIS?
►ANY DEVICE ARTIFICIALLY FABRICATED THAT
AIDS IN THE EFFICIENT ADMINISTRATION OF
RADIOTHERAPY TO THE AFFECTED AREAS AND
THEREBY HELPS IN LIMITING THE POST
THERAPY MORBIDITY.

WHAT ARE VARIOUS TYPES OFWHAT ARE VARIOUS TYPES OF
RADIATION PROSTHESES?RADIATION PROSTHESES?
Radiation carriers
Radiation shielding stents
Radiation cone positioners
Bolus compensators
Position maintaining device
Displacing stents
Dosimeter positioning stent

I.I. RADIATION CARRIERSRADIATION CARRIERS
GPT 8:
Radiation carrier is an ancillary prosthesis used to
administer radiation to confined areas by means of
capsules, beads or needles of radiation emitting
materials such as radium or cesium.
-- Its function is to hold the radiation source securely in
the same location during the entire period of
treatment.
synsyn - CARRIER PROSTHESIS,
INTRACAVITY APPLICATOR,
INTRACAVITY CARRIER,
RADIATION APPLICATOR,
RADIUM CARRIER,

Used in brachytherapy
Used to carry the radiation sources close to
the site of treatment (intracavitary) or
directly into the tumor (interstitial)
TYPES:
Preloaded carriers
After loaded carriers
RADIATION CARRIERS

Both the types of radiation carriers are used in
treatment of accessible superficial oral lesions like
palatal and buccal mucosal lesions
After loaded carriers are usually advantageous
compared to preloaded carriers as the radioactive
sources are placed after the carrier is in position,
hence minimizing the radiation exposure to personnel
handling, positioning and securing such devices.
RADIATION CARRIERS

PRELOADED RADIATION CARRIERS
PRELOADED RADIATION CARRIERS –
METAL RODS

AFTER LOADED RADIATION CARRIERS
PRELOADED RADIATION CARRIERS –
TUBES

NEEDLES
CATHETERS

II.II. RADIATION SHIELD/STENTRADIATION SHIELD/STENT
GPT 8:
 Radiation shield is an intraoral ancillary prosthesis
designed to shield adjacent tissues from radiation
during orthovoltage treatment of malignant lesions of
the head and neck region—
Synonyms- LEAD SHIELD,
TONGUE PROTECTOR

Used to shield the vital structures adjacent to radiation
therapy sites from excess dosage of radiation.
Mostly used to protect tongue, salivary glands and
opposite side of mandible, when buccal mucosa, skin
and alveolar ridge of one side are being treated.
Low melting alloys like CERROBENDCERROBEND,, Pb(26.7%)-
Bi-(50% )Sn(13.3%)Cadmium(10%) , LIPOWITZ are
used as shielding materials.
RADIATION SHIELD/STENT

♥ Lead alone is not suitable for shielding because its
melting temperature is in excess of 6000
F,and hence it
cannot be poured into prosthesis in molten state.
♥ Cerrobend alloy is mostly preferred than lead as it
melting temperature is 1400
F and hence it can be melted
and poured into the cavity prepared in prosthesis with
out adversly affecting methyl methacrylate.

METHOD OFMETHOD OF SHIELD/STENTSHIELD/STENT
FABRICATIONFABRICATION
FOR DENTULOUS PATIENTS:FOR DENTULOUS PATIENTS:
Impressions made for maxilla and mandible with
alginate
When obtaining the mandibular impression, dental
modeling compound is used to displace the tongue
away from the tray on the side for which the stent is to
be fitted.

Casts obtained
If the tongue was not displaced properly while making
the impression, the mandibular cast must be trimmed
so that a 1cm space is created between the tongue
and alveolar ridge.

►3 or 4 strips of baseplate wax are softened and
placed between the teeth, and a bite recorded to form
occlusal index.
►Casts with occlusal index mounted on suitable
articulator, with incisal pin opened to 2-3 mms.

 A wax rim of 1-2 cms thick is prepared to fit into the
lingual space created by reduction of cast or obtained
in the impression.
 Softened wax is placed inside the cast and articulator
closed so that a ring outline form can be moulded.

Wax pattern is invested and processed into methyl
methacrylate to obtain a stent that is finished ,polished
and further refined if necessary.
Cerrobend alloy is melted at 1400
F and poured into
cavity prepared in the prosthesis

When pouring the stent around a corner it is
advisable to utilize clay to block out curved section
and pour one straight section at a time.
A layer of wax or auto polymerizing methyl
methacrylate should be added to the exposed
surface of alloy to prevent back scatter.

The stent can be made by duplicating the patient’s
existing dentures or by making maxillary and
mandibular impressions and mounting on the cast.
The shield is then attached on the lingual side of the
maxilla and mandible as previously described.
FOR EDENTULOUS PATIENTS:

TECHNIQUE OF FABRICATION OF TONGUE
SHIELDING STENT
BY
STEVEN .C.RAMBACH, D.D.S,J .FEMING, D.D.S
(J PROSTHET DENT 1983;49(3);389-392)

III.III. RADIATATION CONERADIATATION CONE
LOCATOR/POSITIONERLOCATOR/POSITIONER
GPT 8:
 Radiation cone locator is an ancillary prosthesis used
to direct and reduplicate the path of radiation to an
oral tumor during a split course of irradiation.
Synonyms-
CONE LOCATOR,
DOCKING DEVICE

 Used to position the peroral cones in a constant
position , thereby directing the radiation beam
consistently over the lesion to be treated and also
protecting the adjacent healthy structures from
irradiation.
 Used in the treatment of superficial
lesions involving anterior floor of mouth,
hard and soft palate.
RADIATATION CONE LOCATOR/POSITIONER

RADIATATION CONE LOCATOR/POSITIONER

BY
GORDON .J. MAHANNA,.D.DJOHN .R. EVANHOE,.D.D.S
RONALD .A,D.D.S
(J PROSTHET DENT 1994;71,600-2)
TECHNIQUE OF FABRICATION OF RADIATION CONE
POSITIONER

CONE
STOP
TONGUE SHIELD

IV.IV. TISSUE BOLUSTISSUE BOLUS
COMPENSATORSCOMPENSATORS
These prostheses helps in treatment of superficial
lesions of face with irregular contours.
Due to irregularities in lesion, some areas with in field
may be untreated, while others may develop isolated
hotspots.

BOLUSBOLUS is a tissue equivalent material placed directly
onto or into irregularities, that help in converting
irregular tissue contours into flat surfaces
perpendicular to the central axis of ionizing beam,
thereby more accurately aid in homogenous
distribution of radiation.
Most commonly used materials for bolus are tissue
conditioners, water, saline, waxes and acrylic resin.

TISSUE BOLUS COMPENSATORS

• BY
RICHARD.MIYAMOTO,D.D.STERENCE.J.FLEMING,D.D.S,
(J PROSTHET DENT 1992;68:115-7)
TECHNIQUE FOR FABRICATION OF A BALLOON RETAINING
STENT TO RETAIN A BALLOON TISSUE BOLUS IN AN ORO-
CUTANEOUS DEFECT

V.V. POSITION MAINTAININGPOSITION MAINTAINING
DEVICEDEVICE
Used to precisely position structures to be
treated in a fixed and repeatable positions for
multiple treatment sessions.
Used to position movable structures mostly
like tongue, soft palate etc..

POSITION MAINTAINING DEVICE
HOLECREATEDINACRLIC
&TONGUEISPOSTIONED

TONGUE POSITION MAINTAINING DEVICE

Patient head positioning stentPatient head positioning stent

VI.VI. DISPLACING STENTSDISPLACING STENTS
Used to move/displace and thereby protect
the vital structures from the field of radiation.
Mostly used in the treatment of lesions
involving the mandibular alveolus, buccal
mucosa and posterolateral borders of tongue
Separates the mandible from the maxilla,
thus sparing the maxilla from the effects of
irradiation.

DISPLACING STENTS

VII.VII. DOSIMETER POSITIONING STENTDOSIMETER POSITIONING STENT
Dosimeter is a device used to calculate the
amount of dosage required for a lesion.
Lithium fluoride capsule are mostly used as
a dosimeter for accurate and efficient means
of determining the dosage locally.
These stents are useful in positioning the
dosimeter appropriately

DOSIMETER POSITIONING STENTDOSIMETER POSITIONING STENT

( J prosthet dent 2003;89:15-18)
•Use of computer tomography for fabrication of a custom
brachytherapy carrier-A clinical report

RADIATION & THE IMPLANTSRADIATION & THE IMPLANTS
Shows advanced bone loss at early stage
Decreases Osseo integration
Increased risk of backscatter radiation
Implants already present & radiation is given implants
receive higher dose of radiation than does the
adjacent tissues (HOT SPOTS)

POST RADIATION CAREPOST RADIATION CARE
good oral hygiene by
Mechanical ,Chemical or other
means
Salt and soda mouth washes
(½ teaspoon of each 3 to 4
hours.)
Radio protectors may also be
employed to reduce the
negative biological effects of
radiation therapy,
1.Mild Mucositis in the localized tumor area

• Abstain from smoking
• Avoid alcohol and caffeine
• Avoid hot, acidic, spiced, coarse, and dry foods- They
• – increase the irritation

2.Mouth ,tender and sore –
--Patient can be expected to lose 5 to 10 pounds of
weight
--Swallowing becomes painful, 0.5 % Dyclone solution—
--- Used 20 to 30 minutes
before each meal.
-- lips should be routinely
moistened, and if necessary,
lubricated with petroleum jelly
to prevent cracking.

Permanent loss of taste and permanent
dryness of the mouth can result from
heavy doses or irradiation
--Occasionally relieved by potassium –
iodine drops or by parotid or other salivary
gland activity.
--Moistened by the use of various
vegetable oils prior to meals.
3.Dryness of the mouth –

(1) Exclusion of 10 to 20% of the gland from the
radiation field can minimize severe symptomatic
xerostomia.
(2) Parasympathomimetic drugs such as Salagen
should be considered (5mg PO TID or QID during
radiotherapy and 3 to 6 months after treatment
completed).
(3) Artificial saliva (such as Moi-ster, Salivart, or
Xerolube) may be used.
(4) Bioten dry mouth products (such as alcohol-free
mouthwash, toothpaste, chewing gum, moisturizing
gel) may be used.
Management

4.Loss of taste4.Loss of taste
 Problem is caused by a temporary degeneration of the
taste buds of the tongue.
 Loss of taste usually persists for approximately four to
six months after the treatment; could be partial or
complete.
Management:Management:
(1) Altered food preparation
(2) Improved salivation may facilitate recovery
(3) Zinc sulfate (200 mg BID) may increase taste
perception and salivation
Salty, bitter,
sour ?

5.Bone necrosis -- serious complications
---Frequent visits to the dentist for
prophylactic maintenance of the teeth.
---caused by impairment of the blood
supply consequent to post irradiation
endarteritis.
TREATMENT
--Hyperbaric oxygen
--Sequestrectomy –Tetracycline
& Saline wash ,Antibiotics & Analgesics
- Bone grafting of mandible

Treatment for ORN may include HYPERBARIC
OXYGEN treatments in which the bone is
subjected to saturation with oxygen in a pressure
chamber

6.Care of teeth
Use of antibiotics,
Long range oral hygiene instruction,
--it reduces sensitvity of teeth to clod,hot & sweet
foods
-- And eventual extraction of teeth as atraumatically as
possible and only when all else fails, would prevent
much of the necrosis now seen.

Conservative dental treatment,FLOURIDE application through
flouride carrier
Fluoride carrier
RADIATION CARIES

7.Trismus
---Trismus occurs as a result of
fibrotic changes to the
muscles of mastication and
the temporomandibular joint
capsule, when they are
included in the radiation
field.
--Put on home exercises
--Mechanical appliances—to
stretch the muscles
E-Z Flex
E-Z Flex jaw exerciser
Tongue blades
corkscrewHydrodynamic exercisers

Mild painMild pain –low grade
analgesics
Severe pain—narcotic
analgesics OR radical
surgical OR nuerosurgical
procedures
8.PAIN

9.Nutritional problems9.Nutritional problems
It is a major cause of morbidity and mortality.
less enjoyment in eating and drinking, or embarrassment
or isolation in social situations
Nausea and vomiting that can follow treatment
Anorexia , Cachexia --progressive loss of body fat and muscle
tissues

Unable to chew and swallow food, tube feeding can safely and
significantly increase the quality of life, maintaining appropriate
weight levels and nutritional requirements.

To maintain patency, the patient should flush the tube with
clear water before and after feedings, or after medications have
been administered through the tube

10.Weight loss10.Weight loss
 Weight loss is common during radiotherapy for head and neck
cancer due to the disease process and treatment toxicity.
 Poor nutrition during radiotherapy may cause severe fatigue and
higher incidence of complications.
Management:
(1) Dietary counseling to help patients to maintain weight and
increase protein and calorie intake is essential.
(2) Aggressive pain control should be used.
(3) When dysphagia from mucositis begins, switch medications to
liquid if possible.

(4) Consider early placement of a nasogastric tube
and institution of supplementation if rapid weight loss
occurs or there is evidence of dehydration.
 (5) Hospitalization may be needed to maintain
hydration and nutritional support.
 (6) Consider PEG-tube if long-term problems are
anticipated.

11.Skin care11.Skin care
Avoid direct sun exposure to
irradiated skin
Use sunscreen (SUV higher than
15)
Use Vaseline for symptomatic dry
skin (such as Eucerin, Aquafor,
RadiCare)

12.Special care for tracheostoma12.Special care for tracheostoma
No metal tubesmetal tubes during treatment (radiation scattering
effect).
Silastic stoma stents, airlon, or plastic tracheotomy
cannula should be used.
If possible, no tubes are preferable as their use may
reduce some of the skin-sparing effects of high-
energy radiotherapy.

13.Speech and Swallowing13.Speech and Swallowing
 The effects of a cancer on speech and swallowing
depend on the location and size of the growthsize of the growth
 Unclear production of labial sounds, and the
patient's ability to hold food in their mouth while
eating may also be reduced.

Reconstructive surgery and the use of prosthetic
devices have become very sophisticated, and current
techniques have been shown to restore oral functioning
to near normal levels
Evaluation and treatment by a speech-languagespeech-language
pathologistpathologist is essential to restore speech intelligibility
and swallowing skills.

CONCLUSIONCONCLUSION
♥ Radiation therapy has been a boon to the medical
profession in the treatment of patients with malignant
conditions.
♥ we, the Prosthodontists can become a great helping
hand to the oncologists and radiation therapists in
improving the quality of the treatment with these
prostheses, there by preventing lot of post irradiation
morbidity.

 This way by having a thorough knowledge of these
appliances, we can improve the quality of life of
patients undergoing radiation therapy.
““When all is Lost…Future still remains.”When all is Lost…Future still remains.”

5. STEVEN .C.RAMBACH, D.D.S,J .FEMING, D.D.S TECHNIQUE OF
Fabrication of tongue shielding stent;
J PROSTHET DENT 1983;49(3);389-
392)
6. GORDON .J. MAHANNA,.D.DJOHN .R. EVANHOE,.D.D.S;RONALD .A,D.D.
Technique of fabrication of radiation cone positioner
J PROSTHET DENT1994;71,600-2
7. Mary Elizabeth Brosky.Chung Lee. tTimoty scott Barlett;
Fabrication of radition bolus prostheses for the maxillectomy
patient ;Jpd 2000;83:119-21
8 . Use of computer tomography for fabrication of a custom Brach
therapy carrier- A clinical report
Jpd 2003; 89:15-8

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