2844-2845 / 3107
Linear – Quadratic Model
• Quantitative explanation of many aspects of radiotherapy
observed at the macroscopic (clinical) level, e.g.
fractionation and dose-rate effects, divergence of
response between tumours and normal tissues, etc.
• Model continues to be developed, e.g. to incorporate
effect of oxygen effects, tumour repopulation, etc.
• Limitations
•
Response at low doses per fraction (<2Gy) –
underestimates biological response
•
Response at high dose per fraction (>10Gy) – not
modelled well
•
Brachytherapy– steep dose gradients