Table 2.

Textural features calculated from fluence maps of volumetric modulated arc therapy (VMAT) plans with various treatment sites

Textural feature	d	Trilogy
		H&N (N = 40)	Prostate (PP) (N = 40)	Prostate (BP) (N = 40)	Liver (N = 11)	Spine (N = 9)
ASM (✕10− 3)	1	1.06 ± 0.33	1.66 ± 0.31	2.12 ± 0.34	1.34 ± 0.39	1.58 ± 0.32
	5	0.82 ± 0.23	1.94 ± 0.38	2.55 ± 0.54	1.32 ± 0.63	1.61 ± 0.59
	10	0.97 ± 0.37	2.98 ± 0.86	6.37 ± 2.92	1.91 ± 1.46	2.34 ± 1.09
IDM	1	0.30 ± 0.04	0.25 ± 0.02	0.23 ± 0.02	0.28 ± 0.03	0.28 ± 0.04
	5	0.16 ± 0.02	0.11 ± 0.01	0.10 ± 0.01	0.13 ± 0.02	0.13 ± 0.02
	10	0.12 ± 0.01	0.08 ± 0.01	0.07 ± 0.01	0.10 ± 0.01	0.10 ± 0.01
Contrast (✕103)	1	0.11 ± 0.04	0.30 ± 0.08	0.51 ± 0.11	0.20 ± 0.11	0.20 ± 0.07
	5	0.41 ± 0.13	1.30 ± 0.35	1.44 ± 0.32	0.89 ± 0.33	0.78 ± 0.11
	10	0.62 ± 0.19	2.28 ± 0.63	3.03 ± 0.57	1.46 ± 0.54	1.25 ± 0.28
Variance (✕10)	1	3.84 ± 0.50	4.50 ± 0.55	5.04 ± 0.34	4.92 ± 0.37	4.42 ± 0.31
	5	3.98 ± 0.52	5.13 ± 0.59	5.17 ± 0.40	5.09 ± 0.42	4.51 ± 0.35
	10	4.01 ± 0.54	5.14 ± 0.63	5.60 ± 0.54	5.15 ± 0.41	4.64 ± 0.38
Correlation	1	0.93 ± 0.02	0.88 ± 0.03	0.80 ± 0.04	0.92 ± 0.05	0.90 ± 0.03
	5	0.76 ± 0.07	0.54 ± 0.09	0.48 ± 0.08	0.67 ± 0.12	0.62 ± 0.06
	10	0.64 ± 0.10	0.24 ± 0.15	0.11 ± 0.14	0.46 ± 0.21	0.45 ± 0.06
Entropy	1	3.21 ± 0.09	2.91 ± 0.06	2.76 ± 0.07	3.06 ± 0.15	3.00 ± 0.14
	5	3.33 ± 0.08	2.85 ± 0.07	2.68 ± 0.09	3.10 ± 0.23	3.02 ± 0.22
	10	3.31 ± 0.09	2.67 ± 0.11	2.36 ± 0.18	3.00 ± 0.33	2.88 ± 0.30
		TrueBeam STx
	d	Lung SABR (N = 20)	Spine SABR (N = 20)	Liver SABR (N = 20)	Brain (N = 20)	H&N (N = 20)
ASM (✕10− 3)	1	2.38 ± 0.99	1.46 ± 0.34	1.78 ± 0.62	1.51 ± 0.50	1.00 ± 0.29
	5	3.02 ± 2.00	1.60 ± 0.58	1.94 ± 0.89	1.33 ± 0.60	0.63 ± 0.14
	10	5.47 ± 4.24	2.05 ± 0.79	3.12 ± 2.11	1.72 ± 1.13	0.70 ± 0.18
IDM	1	0.22 ± 0.03	0.25 ± 0.02	0.26 ± 0.03	0.30 ± 0.04	0.31 ± 0.03
	5	0.09 ± 0.02	0.11 ± 0.01	0.11 ± 0.02	0.13 ± 0.03	0.17 ± 0.02
	10	0.10 ± 0.16	0.08 ± 0.01	0.08 ± 0.02	0.09 ± 0.02	0.13 ± 0.02
Contrast (✕103)	1	0.43 ± 0.20	0.19 ± 0.04	0.22 ± 0.08	0.18 ± 0.12	0.09 ± 0.02
	5	1.65 ± 0.39	1.04 ± 0.22	1.18 ± 0.39	1.05 ± 0.50	0.36 ± 0.13
	10	2.86 ± 1.14	1.52 ± 0.37	1.97 ± 0.91	1.71 ± 0.84	0.53 ± 0.19
Variance (✕10)	1	4.83 ± 0.32	4.43 ± 0.32	4.58 ± 0.39	4.94 ± 0.32	3.77 ± 0.37
	5	5.02 ± 0.32	4.60 ± 0.32	4.75 ± 0.40	5.15 ± 0.33	3.87 ± 0.39
	10	5.24 ± 1.02	4.62 ± 0.30	4.85 ± 0.42	5.24 ± 0.38	3.90 ± 0.40
Correlation	1	0.82 ± 0.08	0.90 ± 0.03	0.90 ± 0.03	0.92 ± 0.05	0.94 ± 0.02
	5	0.34 ± 0.15	0.52 ± 0.09	0.50 ± 0.12	0.61 ± 0.18	0.77 ± 0.08
	10	0.04 ± 0.19	0.30 ± 0.14	0.23 ± 0.22	0.39 ± 0.26	0.66 ± 0.12
Entropy	1	2.71 ± 0.19	3.01 ± 0.11	2.89 ± 0.19	3.03 ± 0.17	3.25 ± 0.07
	5	2.65 ± 0.25	3.01 ± 0.15	2.88 ± 0.24	3.10 ± 0.24	3.42 ± 0.06
	10	2.39 ± 0.52	2.92 ± 0.17	2.74 ± 0.32	3.04 ± 0.30	3.43 ± 0.06

d particular displacement distance, H&N head and neck, PP primary plan, BP boost plan, ASM angular second moment, IDM inverse difference moment, SABR stereotactic ablative radiotherapy