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1/03/2016
2
Target volume includes normal tissue
•
Microscopic tumor
infiltration in surrounding
normal tissue
•
Normal tissues within
tumor (soft tissue, blood
vessels)
•
Normal structures in
entrance and exit dose of
the radiation beam
3
Side-effects cannot, a priori, be
considered a consequence of
incorrect treatment
Why assess adverse effects?
•
To assess the therapeutic ratio
•
eg change in treatment strategy
Probability of
Tumor Control
A
Dose (Gy)
1
0
Therapeutic
Effect (A)
Probability of
Normal Tissue
Damage
Response probability
4
Max. Tolerance