Table 2.

Results displaying absolute percent differences in IWS volumes after performing a shifting or scaling operation on one of the marker boxes compared to IWS volumes using the original marker placing rule. Each individual result is the average percent difference from the CE-CT tumor set. In each case one marker was modified while the other marker was held constant.

	Level 0 (average % change)	Level 1_1 (average % change)	Level 2_2 (average % change)	Maximum variation (%)
Scaling one marker box (vol<1000 mm3)
Outer marker expanded by ±6 pixels	1.44	2.16	1.83	6.92
Outer marker expanded by ±9 pixels	2.18	2.43	2.55	7.14
Inner marker expanded from 20% to 30%	0.72	0.61	1.56	7.37
Scaling one marker box (vol>1000 mm3)
Outer marker expanded by ±6 pixels	2.39	3.99	6.33	21.76
Outer Marker expanded by ±9 pixels	4.23	7.10	5.92	38.40
Inner marker expanded from 20% to 30%	1.66	0.63	1.11	5.25
Shifting marker box from centroid (vol<1000 mm3)
Inner marker shifted (x±2 pixel,y±2 pixel)	8.12	5.97	7.28	23.26
Outer Marker shifted (x±2 pixel,y±2 pixel)	3.60	5.47	4.96	16.46
Shifting marker box from centroid (vol>1000 mm3)
Inner marker shifted (x±2 pixel,y±2 pixel)	1.34	0.76	0.97	7.25
Outer Marker shifted (x±2 pixel,y±2 pixel)	0.95	1.76	2.36	32.64