DEOEC Institute of OncologyDepartment of Radiotherapy

Radiology: diagnosisRadiotherapy: part of active oncotherapy (oncoradiology, radiation oncology)Oncology:chemotherapy

The branch of clinical medicine which uses ionising radiation, either alone or in combinations with other modalities, for the treatment of patients with cancer (or benign diseases). It includes responsibility for the treatment, follow up and supportive care of the patient as an integral of the multidisciplinary management of patients.

external beam radiation is delivered from outside the body by using a machine to aim high-energy rays (x-rays, gamma rays or photons). TELETHERAPY

internal radiation is delivered from inside the body by placing radioactive material, sealed in catheters or seeds, directly into the tumor. BRACHYTERAPY

1. „Direct hit”2. „Activated water”

1. „Direct hit”2. Activated

water O2 is

necessary

H2O

H+ OH- e-

H2 H2O2 H2O

oxidation

reduction

1. Lethal damage2. Sublethal damage

a) loss of reproductibility apoptosis

b) Repairc) Reoxigenistaiond) Repopulatione) Redistribution

1. Lethal damage2. Sublethal damage

a) loss of reproductibility apoptosis

b) Repairc) Reoxigenistaiond) Repopulatione) Redistribution

1. Lethal damage2. Sublethal damage

a) loss of reproductibility apoptosis

b) Repairc) Reoxigenistaiond) Repopulatione) Redistribution

EXCISIONS REPAIR

EndonucleazExonucleaz

↓Polymeraz

Liaz

MISMATCH REPAIR

1. Lethal damage2. Sublethal

damagea) loss of reproductibility

apoptosisb) Repairc) Reoxigenistaiond) Repopulatione) Redistribution

G. Steel, Basic Clinical Radiobiology 1997, second edition

In vitro effect of hypoxic conditionson radiation-induced cellular lethality

Cells are much more sensitive to x-rays in the presence of molecular oxygen than in its absence. The ratio of doses under hypoxia to those under oxia necessary to produce the same level of cell killing is close to 3.

OER = 2.8

Hypoxicoxic

50 1510 2520 30

0.001

0.01

0.1

1

10

Survi

ving f

ractio

n

Radiation dose (Gy)

OER (Oxygen enhancement ratio) = Radiation dose in hypoxia/ Radiation dose in air

1. Lethal damage2. Sublethal damage

a) loss of reproductibility

apoptosisb) Repairc) Reoxigenistaiond) Repopulatione) Redistribution

Hypoxia in tumors can results from two quite different mechanisms: chronic and acute hypoxia

Horsman MR and Overgaard J. 1992; Eur J. Cancer 28: 717-8

ChronicallyHypoxic Cells

AerobicCells

FunctionalBlood Vessel

NecroticCells

Acutely HypoxicCells

1. Isotopes isotope halfing time energy

(MeV) Ra-226 1626 y 0,830 Co-60 5,26 y 1,250 Ir-192 74,2 d 0,380 J-125 60,2 d 0,028

2. Cobalt unit Gamma-ray (photons)

Co60→ gamma-photons

3. Linear acceleratorPhotons and electrons

Precisely locate the target Hold the target fixed Accurately aim the radiation beam Shape the radiation beam to the target Deliver a radiation dose that damages

abnormal cells yet spares normal cells

Topometric-CTNo contrast media

Image fusions

GTV: gross tumor volume macroscopic tumor or tumor bed

CTV: clinical target volume: GTV+1-2 cm safety margin –microscopic tumor spreading-

PTV: planning target volume: CTV+0,5-1 cm movements of organs or breathing

Postop.Cervical cancer

3D –Target Volumes

MLC (multileaf collimator system)

TELETHERAPY: Fixed beam irradiation : direct field opposed fields 4 or more fields

TELETHERAPY: Fixed beam irradiation : direct field opposed fields 4 or more fields

BRACHYTHERAPY: Intracavital Intersticial

BRACHYTHERAPY: Intracavital Intersticial

EX. 1

EX.2

EX. 3

EX. 4

EX.5

Positioning, immobilisation devices Thermoplastic masks

Breast-boards

Conventional dose: 1,8-2 Gy/day, 5 day/week 2-7

week

Tumor killing doses: 30-78 Gy - hystology, tumor

type

- TNM stage,

KPS, ECOG

- indications

(neoadjuvant, adjuvant,

definitive, palliative)

- combinations

(RKT)

Conventional dose: 1,8-2 Gy/day, 5 day/week 2-7

week

Tumor killing doses: 30-78 Gy - hystology, tumor

type

- TNM stage,

KPS, ECOG

- indications

(neoadjuvant, adjuvant,

definitive, palliative)

- combinations

(RKT)

Tolarance of normal tissues (risk organs)

DVH: Dose-volume histograms

1. Simulation, positioning2. Topometric CT3. Treatment plan4. Resimulation5. Verification6. Treatment

1. Simulation, positioning

2. Topometric CT3. Treatment plan4. Resimulation5. Verification6. Treatment

1. Simulation, positioning

2. Topometric CT/MR

3. Treatment plan4. Resimulation5. Verification6. Treatment

1. Simulation, positioning

2. Topometric CT/MR

3. Treatment plan4. Resimulation5. Verification6. Treatment

Pictor 3D laser system

IsocenterVirtual point

1. Simulation, positioning

2. Topometric CT/MR

3. Treatment plan4. Resimulation5. Verification6. Treatment

RESULTS: 1. LTC : CR (4 mts) PR (-25-50%)

NC PD

2.Survival: Overal, Disease free, TTP

SIDE EFFECTS : early late local inflammation fibrosis

general weakness disfunction