1622-1623 / 2953
This is why some planning system calculate
simplified beamlet doses:
too steep and/or truncated penumbra,
esp. in presence of inhomogenieties
thus, OARs may wrongly appear
sufficiently spared
• computation time issue
• computer memory issue (10.000
beamlets can be ~Gigabyte memory)
Precise dose computation DURING fluence profile
optimization is immensely expensive!
ESTRO IMRT course 2016
IMRT optimization: algorithms&cost functions
London April 4th, 2016
-37-
4 mm x 2 mm beamlet, 15 MV, 3D-PB
the final, more precise dose calculation
reveals such initial simplifications!
→
plan degradation of segmented
plan!
5 cm!