The use and QA of biologically related models for treatment planning: short report of the TG-166 of the therapy physics committee of the AAPM

AAPM task group report on biologically based treatment planning. It describes the common models — the Poisson TCP model, empirical sigmoid TCP models defined by D50 and a normalized dose-response gradient, and the Lyman-Kutcher-Burman NTCP model with parameters TD50, m and n — defines serial and parallel organs and the volume effect, and advises using the LQ-equivalent dose in 2 Gy fractions rather than physical dose in TCP and NTCP calculations. Its recommendations: plan evaluation should at present be based on established dose-volume criteria; relative TCP/NTCP estimates may help choose between rival plans if users understand the models and parameters in their planning system; absolute TCP/NTCP estimates are not warranted as the main indicators of plan quality; and review of the 3D dose distribution should always remain part of plan evaluation. Read in the AAPM report PDF (Report No. 166, March 2012).

The AAPM guide to biological models (EUD, TCP, NTCP) in planning systems — what the common models are, and how far their numbers can be trusted in plan evaluation.