474 / 1578
Motion compensation techniques
4D
è
The tumour is ~10% of the time at 50%
of the dose
è
This only accounts for about 5%
underdose
è
Even with large amplitudes, the margin
needs not to be large.
è
Mid-ventilation or Mid-position approach
•
The radiation beam does not necessarily need encompass the
complete breathing amplitude
Ø
Broad beam penumbra in the lung tissue
Ø
Time spend at edges of “ITV” is short
Ø
Dose loss at edges can be compensated for by higher doses at the centre
SBRT 2017 - D. Verellen