BIPH6106 radiation therapy oncology UWI STA

rad oncology

1. Radiation Oncology
BIPH6106
Lecture 1.
2017

2. CELL cycle.

4. Radiation
therapy

5. Radiation therapy
Radiotherapy
Radiation oncology

6. Radiationtherapy(alsoradiotherapyor
radiationoncology,sometimesabbreviatedtoXRT)is
themedicaluseofionizingradiationaspartofcancer
treatmenttocontrolmalignantcells(nottobe
confusedwithradiology,theuseofradiationin
medicalimaginganddiagnosis).Radiotherapymaybe
usedforcurativeoradjuvantcancertreatment.Itis
usedaspalliativetreatment(wherecureisnot
possibleandtheaimisforlocaldiseasecontrolor
symptomaticrelief)orastherapeutictreatment(where
thetherapyhassurvivalbenefitanditcanbe
curative).

7. Totalbodyirradiation(TBI)isaradiotherapy
techniqueusedtopreparethebodytoreceivea
bonemarrowtransplant.Radiotherapyhasseveral
applicationsinnon-malignantconditions,suchas
thetreatmentoftrigeminalneuralgia,severe
thyroideyedisease,pterygium,pigmented
villonodularsynovitis,preventionofkeloidscar
growth,andpreventionofheterotopicossification.
Theuseofradiotherapyinnon-malignant
conditionsislimitedpartlybyworriesaboutthe
riskofradiation-inducedcancers.

8. Radiotherapyisusedforthetreatmentof
malignanttumors(cancer),andmaybeusedasthe
primarytherapy.Itisalsocommontocombine
radiotherapywithsurgery,chemotherapy,hormone
therapyorsomemixtureofthethree.Mostcommon
cancertypescanbetreatedwithradiotherapyinsome
way.Theprecisetreatmentintent(curative,adjuvant,
neoadjuvant,therapeutic,orpalliative)willdependon
thetumourtype,location,andstage,aswellasthe
generalhealthofthepatient.

9. Clinical-Biological Bases of RT of Tumors
The therapeutic use of IR is based on it’s
biological action, that is, it’s ability to cause
changes in cells, tissues, organs, the body as
a whole. It depends on the
ABSORBED
DOSE
(AD) –e n e r g y transmitted to
irradiated tissues (Gy).

10. Tosparenormaltissues(suchasskinor
organswhichradiationmustpassthroughin
ordertotreatthetumour),shapedradiation
beamsareaimedfromseveralanglesofexposure
tointersectatthetumour,providingamuch
largerabsorbeddosetherethaninthe
surrounding,healthytissue.

11. Dose
Theamountofradiationusedin
radiationtherapyismeasuredingray(Gy),
andvariesdependingonthetypeandstage
ofcancerbeingtreated. Forcurativecases,
thetypicaldoseforasolidepithelialtumor
rangesfrom60to80Gy,whilelymphoma
tumorsaretreatedwith20to40Gy.

12. Fractionation
Thetotaldoseisfractionated(spreadoutovertime)forseveral
importantreasons.Fractionationallowsnormalcellstimetorecover,
whiletumorcellsaregenerallylessefficientinrepairbetween
fractions.Fractionationalsoallowstumorcellsthatwereina
relativelyradio-resistantphaseofthecellcycleduringonetreatment
tocycleintoasensitivephaseofthecyclebeforethenextfractionis
given. Similarly,tumorcellsthatwerechronicallyoracutely
hypoxic(andthereforemoreradioresistant)mayreoxygenate
betweenfractions,improvingthetumorcellkill.

13. Typesofradiationtherapy
Historically,thethreemaindivisionsofradiotherapyare
externalbeamradiotherapy(EBRTorXBRT)orteletherapy,
brachytherapyorsealedsourceradiotherapy,andsystemic
radioisotopetherapyorunsealedsourceradiotherapy.The
differencesrelatetothepositionoftheradiationsource;external
isoutsidethebody,brachytherapyusessealedradioactivesources
placedpreciselyintheareaundertreatment,andsystemic
radioisotopesaregivenbyinfusionororalingestion.
Brachytherapycanusetemporaryorpermanentplacementof
radioactivesources.

14. Thetemporarysourcesareusuallyplacedbyatechnique
calledafterloading.Inafterloadingahollowtubeorapplicator
isplacedsurgicallyintheorgantobetreated,andthesources
areloadedintotheapplicatoraftertheapplicatorisimplanted.
Thisminimizesradiationexposuretohealthcarepersonnel.
Particletherapyisaspecialcaseofexternalbeamradiotherapy
wheretheparticlesareprotonsorheavierions.Introperative
radiotherapyisaspecialtypeofradiotherapythatisdelivered
immediatelyaftersurgicalremovalofthecancer.Thismethod
hasbeenemployedinbreastcancer(TARGetedIntroperative
radioTherapy),braintumoursandrectalcancers.

18. ParticleTherapy
Inparticletherapy(Protontherapy),energetic
ionizingparticles(protonsorcarbonions)aredirected
atthetargettumor.Thedoseincreaseswhilethe
particlepenetratesthetissue,uptoamaximum(the
Braggpeak)thatoccursneartheendoftheparticle's
range,anditthendropsto(almost)zero.The
advantageofthisenergydepositionprofileisthatless
energyisdepositedintothehealthytissuesurrounding
thetargettissue.

19. Principles of Radiotherapy
1. Delivering of an optimal doseto the
tumor
2. Minimal damage of surrounding
organs
&tissues.
3. Measures stimulating protective
forces of the body

22. RadioisotopeTherapy(RIT)
Systemicradioisotopetherapyisaformoftargetedtherapy.
Targetingcanbeduetothechemicalpropertiesoftheisotope
suchasradioiodinewhichisspecificallyabsorbedbythethyroid
glandathousandfoldbetterthanotherbodilyorgans.Targeting
canalsobeachievedbyattachingtheradioisotopetoanother
moleculeorantibodytoguideittothetargettissue.The
radioisotopesaredeliveredthroughinfusion(intothe
bloodstream)oringestion. Examplesaretheinfusionof
metaiodobenzylguanidine(MIBG)totreatneuroblastoma,oforal
iodine-131totreatthyroidcancerorthyrotoxicosis,andof
hormone-boundlutetium-177andyttrium-90totreat
neuroendocrinetumors(peptidereceptorradionuclidetherapy).
Anotherexampleistheinjectionofradioactiveglassorresin
microspheresintothehepaticarterytoradioembolizelivertumors
orlivermetastases.

23. Today more than 70 % of oncological
patients obtain radiation treatment
•as initial
•in connection with relapses of disease
•with the palliative purpose

24. Treatment of tumors may be:
RADICAL RT– complete cure of the patients –
Indications: an early stages (I-II).
PALLIATIVE RT-a temporary improvement of
patients life, life prolongation (stages III- IV).
SYMPTOMATIC RT -to alleviate the most
severe manifestations of the disease

25. Approximately 45 % are cured
22 –surgery (independently or in combination)
18 –radiation therapy (independentlyor as a
leading method)
5 –chemotherapy (independentlyor, more
often, it is combined with surgery and
radiation therapy)

26. The role of a radiotherapy grows
because of early diagnostics
of oncological diseases

27. Radiotherapeutic Interval
Selection of an irradiation regimen:
delivery of an optimal total tumor dose (TTD)
Radiosensitivityof healthy and tumor
cells is practically the same.
The radiotherapeutic interval is a
difference between radiosensitivity of the tumor
and surrounding healthy organs and tissues
It should be increased

28. Mechanisms of cells’ death
1.interphase death
(apoptosis)
2.loss of reproductive
ability

30. Factors of modification
•Natural radiosensitivity
•Oxygen
•Cellular restitution
•Restitution of potentially lethal damages
•Cellular cycle
•Cellular proliferation

31. Methods of radiomodification
Oxygenous effect:
Oxybaroradiotherapy
Hypoxiradiotherapy
-gaseous hypoxia- protection of
normal tissues
Chemical compounds:
Radiosensibilizers
Hyperthermia
Polyradiomodification

32. Normal tissues, which
radiosensitiveness can essentially
influence on planning of treatment
and/or the appointed dose
Organs of hazard

33. Effect of a radiotherapy
depends on a dose
in a tumour

34. Factors of therapeutic dose
limitation
•tolerance ofnormal
tissues around a tumour,
that is
•acute responses of tissues
•late radiation effects

35. Radiations for radiotherapy
•photons
•electrons
•beta particles
•heavy particles
(protons, neutrons)

36. Sources of
radiotherapeutic radiations
•X-Rays
•linacs
•cyclic accelerators
•nuclear reactors
•radionuclides

37. Methods of radiotherapy

38. On distance Source –Target
•Distant irradiation
•Contact irradiation
(Brachytherapy)

39. On localization of source
•outside irradiation
•intracavitary irradiation
•interstitial irradiation
•enteral or parenteral introducing of
radionuclides

40. On type of apparatus
•Roentgenotherapy (X-Rays)
(low voltage, orthovoltage)
•Telegammatherapy
•Therapy by photons of a linac
•Therapy by electrons of a linac
•Brachytherapy by the closed radionuclides
•Brachytherapyby "grains" of radionuclides

41. Methods of patient’s irradiation
S t a t i c irradiation can be performed
through:
Single field technique
Multiple field technique
M o b i l e irradiation:
Rotational

42. Contraindicationsfor RT
grave patient’s state, cachexia, anemia,
leukopenia, acute septic states
decompensated states of heart, liver, kidneys
Active tuberculosis
Extension of tumors to adjacent hollow
organs, growth into great blood vessels. An
inflammatory process

43. RT of NON-TUMOR DISEASES
It is carried out only according to strict
indicationswhen other methods failed
Single and total doses should be small in the range
of 0.1- 0.7 Gy every alternate day up to a TFD of 4- 7
Gy
The basic method is a direct local irradiation of the
focus using the remote technique
Radiation field is equal to the focal size
The X- ray unit or telegammatherapy is used at
deep foci (more often X-ray therapy )

44. Inflammatory processes
We cause local plethora, an increased
permeability of capillaries, formation of bioactive
substances, lymphocytolysis
The principle of treatment –the severe the process,
the lower the dose.
At the initial stage, it is possible to terminate the
process, alleviate pain, relieve inflammation.
At phase of necrosis and purulation -rapid infiltrate
melting and its delimitation.
At the phase of regeneration –rapid wound
epithelisation.

51. Clinical- dosimetric planning of RT
The main clinical-
dosimetric task is to
create the most
favorable spatial
distribution of absorbed
radiation doses
in patient’s body
EXTERNAL BEAM
THERAPY

54. Accuracy of dose application
On quantity
+7 ÷-5 %
In space
±3 mm

55. Protection of the
patient at a
radiotherapy

56. 1. Confidence that the radiotherapy
will bring benefit to the patient

57. 2. Optimization of protection –
adequate dose in a target
and decreasing of dose up to
reasonably achievable level in
other tissues

58. 1.2 millions of new oncological diseases
are registered in EU (2000)
Cured alive patients –11 millions

59. THANKSFOR YOUR ATTENTION!