TABLE VII.

Template variables for volume estimation. Initial estimates are determined prior to matching: centroid from manual estimation, background and lesion density from regions on the edge and center (respectively) of the volume of interest. The half-pixel offsets in x, y are created by repositioning the object prior to CT simulation, and the quarter-pixel offsets in z are created by decimating a high-resolution template.

Variable	Values	Step size
Centroid pixel offset	Initial estimate ± 3 pixels	0.5 pixels in x, y; 0.25 in z
Background density	Initial estimate ± 30 HU	1 HU
Lesion density	Initial estimate ± 20 HU	1 HU
Lesion size	80%–120% of ground truth diameter mm	1% of ground truth diameter mm