Basic Treatment Planning

Dose in ICRU83

Level 1. Why is it not adequate today?

-The absorbed dose distribution for IMRT can be less homogeneous then in CRT

-Each beam can produce absorbed dose with large dose gradients

- Large dose gradients (10%/mm) in the PTV boundary i.e. small shifts in delivery can affect the reliability of using a single point to report the dose

- Because modern TPS have evaluation tools that makes it possible.

- Monte Carlo calculations have statistical fluctuation in the results for small volumes which makes it difficult and uncertain to determine an absorbed dose to a point.