RADIOTHERAPY. PART 1.ppt THE PPT IS IN PARTS . IT IS FIRST PART

RADIOTHERAPY , ORAL CANCER

1. RADIOTHERAP
Y
Presented By:
SONIA GULIA
PG III Year

2. CONTENTS
INTRODUCTION
PRINCIPLE
RADIOBIOLOGY
PHYSICAL CONCEPT
METHODS
SIDE EFFECTS
ADVANTAGES
DISADVANTAGES
FRACTIONATION
INDICATION
POST RADIATION PROTOCOL
NEWER MODALITIES
REFERENCES

3. INTRODUCTION
•Thefirstknownreferencetocancerorcancerlikediseaseinman
wasdocumented4500to5300yearsback.
•MalignancyhasbeendefinedbySirRupertWillis
•“Asagroupofabnormalmassoftissues,thegrowthofwhichfar
exceeds,andisun-coordinatedwiththatofthenormaltissuesand
persistsinthesameexcessivemanneraftercessationofstimuli
whichevokedthechange.”
•Nohumantissueisimmunetomalignancy.
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4. The basic modalities of cancer treatment are
Surgery
Radiotherapy
Chemotherapy
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5. HISTORY
Dr.EmileGrubbeofChicago,U.S.A.claimedthathetreateda
womenwithbreastcancerusingRoentgenraysin1896andheis
creditedtobethefirstphysiciantoclinicallyutilizeradiationtherapy.
SubsequentlyMadameCuriein1898gaveanewdimensiontothis
specialtybythediscoveryofradium.
Surprisingly,AlexanderGrahamBell,theinventoroftelephonewas
themastermindbehindthediscoveryofinterstitialbrachytherapy
whenhesuggestedtoDr.Z.T.Sowersin1903,totryplacingradium
intotheveryheartofthetumor.
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6. Theconceptoftime,doseandfractionationoriginatedinsubsequent
yearsbetween1920-1940.
Earlypracticeofbrachytherapywaslargelyempiricalandextended
upto1930s.
ThetermbrachytherapywasproposedforthefirsttimebyDr.G
Forssellin1931.
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7. DEFINITION
Radiotherapyalsocalledradiationtherapy,isthe
treatmentofmalignant(andoccasionallynon-
malignant)diseasesusingionizingradiation.
Radiationoncologyisthesciencewhichdealswith
thestudyoftumorbiologyandapplicationofthe
ionizingradiationinthemanagementofcancer.

8. PRINCIPLES
Rapidlyproliferatingcellsaremoresensitivetoionizing
radiationcomparedtonormalcells.
Goal:Sterilizetumor,preserveadjacentnormaltissue.
Lethaldosesamefornormalandabnormaltissues.
Normaltissues:Repair

9. Baseline Investigations
Complete history and physical examination
Complete documentation of the extent of
primary and regional disease
ENT evaluation
Routine blood tests
Chest X ray, OPG
CT/MRI
Biopsy
Pregnancy test

10. Tumor Board
Oral medicine specialist
ENT Surgeon
General surgeon
Radiotherapist
Chemotherapist
Immunotherapist
Clinical psychologist
Dietician
Registered nurse with onco-training

11. Role of Radiotherapy
1.SCCisusuallyradioresponsive,inearlystages
highlyradiocurable
2.Moredifferentiatedtumor:lessrapidradiation
response,highdose
3.Exophyticandwelloxygenatedtumors:more
radioresponsive
4.SCCwhenlimitedtomucosahighlyradiocurable
5.Boneandmuscleinvolvement:decrease
radiocurability
6.Earlysmallmetastases:radiationtherapyalone

12. INDICATIONS
1.T1-T2lesions
2.T3-T4locallyadvancedlesions:postsurgical
treatment,RTwith/withoutChemotherapyespecially
fororganpreservation
3.Cervicallymphnode:Clinicallypositivelymphnodes

13. INDICATIONS FOR
POSTOPERATIVE
RADIOTHERAPY
Positiveresectedmargins
Multipleinvolvednodes
Extracapsularextension
Locallyadvancedprimaryregardlessofmargin
Perineuralspread
Vascularandlymphaticemboli

14. TIMING Of RADIATION
Whentissuesarewellhealed.
Morethan6weeksdelaycanadverselyaffectthe
outcome
CombinedChemotherapyandRadiotherapy
NeoadjuvantChemotherapy
ConcurrentorConcomitantChemotherapy
AdjuvantChemotherapy

15. DOSE
Tumor site
Size of the lesion
Volume
No. of fractions
Various techniques
Tolerance
Medical conditions
50-55 Gy in 25-30 fr over 5-6 weeks: microscopic or
occult disease
65-70 Gy over 7 wks : Gross tumor
Initial 50Gy to primary lesion and regional nodes then
boost dose.

16. Preradiotherapy evaluation
Avoidendodontics
Extractteethwithlesion2wksbeforeRT
Fluorideapplication
Avoidperiodontaltreatment
Removepartiallyeruptedthirdmolars

17. METHODS OF DELIVERY
Teletherapy
Superficial:30-125KV,skintumors
Orthovoltage(Kilovoltage):200-300kv,superficially
situatedtumors
TelecobaltTeletherapy(CO60):Gammarays-1.25
Mev,Easyandsafe,Maxdose5mmbelowskin:Skin
sparingeffect
LinearAccelerator:Above1Mv,deepseatedtumors,
skinsparing,mostcommonlyused

18. Brachytherapy
ItisderivedfromtheGreekword“brachy”whichmeans“short
range”.
Thenationalcouncilonradiationprotection(1972)definedtheterm
brachytherapyasamethodofradiationtherapyinwhichan
encapsulatedsourceoragroupofsuchsourcesisutilizedtodeliver
thegammaradiationatadistanceofuptoafewcentimeters,either
bysurface,intracavity,orinterstitialapplication.
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19. Generallyadoseof65Gyover6-7daysisgivenwhenitisusedas
thesoletreatment.
TheOptimumrangeofgammarayenergyis0.2to0.4Mev.
Thesourcecanbemadeindifferentshapesandsizes–tubes,
spheres,andflexiblewirestosuitvariousclinicalneeds.
Materialsshouldwithstandsterilizationprocess.
Radium-226
Caesium-137
Cobalt-60
Iridium-192
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20. Advantages
Ahighdoseofradiationcanbedelivereddirectlytothetumor
sparingsurroundingnormaltissues.
Treatmenttimeisshort.
DISAdvantages
Itcanbeusedonlyinselectedcasesespeciallyintheearlystageof
diseaseataccessiblesites.
Itrequiresanaesthesiaandexcellentexpertise.
Itisaninvasiveprocedure.
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21. Types of brachytherapy
Mould therapy brachytherapy
Intracavity brachytherapy
Intraluminal brachytherapy
Interstitial brachytherapy
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22. Mould therapy
Thismethodwasthemostattractiveonebecauseoftheeasiness
withwhichradiumcanbeappliedoverthebodyforthetreatment.
Thebaseontowhichradiumtubesorneedlesweremountedwas
eitherwax,plasterofParisoranysuitablematerial.
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23. INDICATIONS
Squamous and basal cell skin lesions of scalp, forehead,
dorsum of hand and foot
Tip of nose
Lip
Floor of mouth
Hard palate
Pinna of the ear
Vagina
Anus
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24. Limitations
Thetumorareashouldnotexceedadistanceof3cmfromthemould
surface.
Themouldshouldbedesignedsuchthatitiscomfortabletothe
patientandthedailyapplicationandremovaldoesnotresultin
breakageorslippageofsource.
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25. Intracavity therapy
Treatmentbyplacementofradioactivesourcesinsidenaturalbody
cavitiesiscalledanIntracavitytherapy.
Gynecologicalmalignancies-mostimportantapplication
Carcinomaofnasopharynx
Carcinomaofcervix
Carcinomaofoesophageal
Lungtumor
Veryhighdosescanbedeliveredtothetumorbythismethod
becauseofthepresenceofsourcesintheclosevicinityoftumorand
atthesametimeverylessdosewillbedeliveredtonormal
structures.
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26. INTRALUMINAL brachytherapy
Duringthelasttwodecadestheintraluminalbrachtherapy
techniquesaregainingwideappeal.
Sitesforwhichitisusedare:
Esophagus
Bronchus
Nasopharynx
Rectum
Biliarytree
Ano-rectum
Itgivespalliativetreatmentinoneortwosittingsinadvanced
casesofcancer.
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27. Intersitialbrachytherapy
Inthisradioactivesourcesareimplantedintothetumorand
surroundingtissuesandallowedtoremainthereforadefinitive
period(temporaryimplants)orindefinitely(permanent).
Thesourcescanbeinformofneedles,wiresandseeds.
Itcanbeusedin:
Carcinomaoftongueandbuccalmucosa
Squamouscellcarcinomaofheadandneckregion,skin,breast
tumor,softtissuesarcomaetc.
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