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ESTRO IMRT course 2015
IMRT optimization: algorithms&cost functions
Brussels October 5th, 2015
-36-
4 mm x 2 mm beamlet, 15 MV, 3D-PB
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
the final, more precise dose calculation
reveals such initial simplifications!
→
plan degradation of segmented
plan!
5 cm!
• computation time issue
• computer memory issue (10.000
beamlets can be ~Gigabyte memory)
Precise dose computation DURING fluence profile
optimization is immensely expensive!