Table 1.

Comparison of the DIR accuracy in different grid resolution in RayStation. The DSC and JD for the ROIs and TRE for the multiple points were calculated using the analysis tools in the software. The average values for ten patients were tabulated. The significant difference was detected by two‐tailed paired t‐test (p < 0.05)

Grid resolution (mm)	Hybrid DIR			Intensity‐based DIR
	1 × 1 × 1	2.5 × 2.5 × 3	5 × 5 × 5	1 × 1 × 1	2.5 × 2.5 × 3	5 × 5 × 5
DSC
Bladder	0.98 ± 0.01	0.97 ± 0.01	0.96 ± 0.01a	0.77 ± 0.10	0.78 ± 0.10	0.77 ± 0.10
Prostate	0.96 ± 0.01	0.96 ± 0.01	0.95 ± 0.01	0.74 ± 0.14	0.75 ± 0.14	0.74 ± 0.14
Rectum	0.93 ± 0.02	0.93 ± 0.03	0.91 ± 0.02	0.70 ± 0.09	0.72 ± 0.09	0.70 ± 0.08
SV	0.87 ± 0.09	0.88 ± 0.08	085 ± 0.08	0.35 ± 0.21	0.38 ± 0.20	0.35 ± 0.21
JD
Bladder	0.90 ± 0.27	0.91 ± 0.26	0.91 ± 0.26	0.98 ± 0.02	1.00 ± 0.03	1.00 ± 0.01
Prostate	0.87 ± 0.27	0.87 ± 0.27	0.87 ± 0.26	0.96 ± 0.04	0.97 ± 0.05	1.00 ± 0.01
Rectum	0.93 ± 0.23	0.93 ± 0.23	0.91 ± 0.22	0.93 ± 0.06a	0.99 ± 0.05	0.99 ± 0.01
SV	0.49 ± 0.21	0.48 ± 0.22	0.48 ± 0.20	0.97 ± 0.04a	1.03 ± 0.07	1.00 ± 0.02
TRE (mm)
	2.2 ± 1.8	2.4 ± 1.8	1.7 ± 1.7a	1.8 ± 1.2a	2.2 ± 1.3	1.4 ± 1.1a

DIR, deformable image registration; JD, Jacobian determinants; SV, seminal vesicles; DSC, dice similarity coefficient.

^a p < 0.05.