Figure 3From: Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markersIsocenter placement errors (in cm) on during-treatment EPIs (gray circles; n = 530 fractions), relative to the expected pre-treatment isocenter position, along a): S-I and A-P axes, and b): S-I and L-R axes. Ellipse shows 95% confidence intervals for CTV coverage in each direction.Back to article page