Table 1.

Localization errors and planning target volume (PTV) margin calculated by the van Herk formula and Yoda's variant using 14 prostate patient data, with x-axis going from left to right, y-axis going from anterior to posterior, and z-axis going from cranial to caudal directions. Mean shows patient average of mean localization errors among fractions for each patient. Σ shows the standard deviation of mean localization errors among fractions for each patient. σ shows the root mean square of the standard deviation of the localization errors among fractions for each patient.

	x (mm)	y (mm)	z (mm)
Mean	0.28	0.49	0.79
Σ	0.67	1.22	1.38
σ	0.66	1.85	1.35
Van Herk [12, 13]	2.1	4.3	4.4
Yoda and Nakagawa [14]	1.9	3.9	3.9