Figure 2. The differences of 2-mm wall volumes outside GTV between the two systems.

The scatter plots show the correlations between the GTVs and the 2-mm wall volumes outside the GTVs in the sphere models (A) and clinical brain metastases (BMs) (B).

A: The spherical models are assumed to be GTVs. B: The 2-mm outer walls are the GTV + 2 mm structures by MIM Maestro and Monaco minus GTV. The solid lines indicate the calculated volumes for the sphere models.

BM: brain metastasis; GTV: gross tumor volume; GTV + 2 mm: GTV evenly expanded by 2 mm.