Fig. 3From: Combined effect of dose gradient and rotational error on prescribed dose coverage for single isocenter multiple brain metastases in frameless stereotactic radiotherapyNormal brain volume irradiated with 12 Gy versus GI. a Results with iso-radius of 2.5 cm and b 5 cm with a linear fit. Arrowed GI values are underestimated as explained before, and expected to be similar to those obtained with an iso-radius of 5 cm. The steeper gradient (smaller GI) leads to a smaller volume irradiated with 12 Gy, and the linear relationship can be seen in (b)Back to article page