a), b), c), d) and e) show 3%/3mm gamma index variation and passing rates for the 4 lesion SRS plan with MLC offsets of 0mm,1mm,2mm,3mm and 4mm, respectively. The original SRS plan and the corresponding gamma pass rate is also shown in Figure 9, last column. f), g), h), i) and j) show gamma index for the same criteria but for gantry angle errors. f), g), h), i) and j) correspond to gantry angle errors of 0, 1, 3 and 4 degrees, respectively. TPS data were used as the reference dataset.