Table 1. Averaged positional error of simulation experiment up to a 15-mm depth.

	horizontal error	depth error	total error
total area	1.0 ± 0.9 mm	2.7 ± 3.0 mm	3.1 ± 2.9 mm
source area	1.0 ± 0.7 mm	1.9 ± 1.3 mm	2.2 ± 1.3 mm
detector area	1.0 ± 0.8 mm	1.8 ± 1.3 mm	2.2 ± 1.3 mm
midpoint area	0.1 ± 0.5 mm	1.2 ± 1.1 mm	1.2 ± 1.2 mm
distant area	1.1 ± 0.7 mm	5.5 ± 4.0 mm	5.7 ± 3.9 mm