Dosimetric comparison of deformable image registration and synthetic CT generation based on CBCT images for organs at risk in cervical cancer radiotherapy

Table 4 Dose metric errors for different contours using dpCT-based dose distribution (%)

Category	Contours for comparison	Small Intestine		Rectum		Bladder		Spinal Cord		Femoral Head L		Femoral Head R		Bone Marrow
Category	Contours for comparison	Dmean	D2	Dmean	D2	Dmean	D2	Dmean	D2	Dmean	D2	Dmean	D2	Dmean	D2
Smaller Diff(V_CBCT,V_pCT) (20 cases)	pCT contours vs. CBCT contours	1.443	8.166	0.687	3.907	0.314	3.400	4.972	2.659	1.957	3.446	2.064	3.559	0.744	1.540
	dpCT contours vs. CBCT contours	1.379	9.440	0.417	2.102	0.290	2.809	3.527	2.607	1.579	2.986	1.452	3.253	0.568	1.234
	sCT contours vs. CBCT contours	0.609	7.334	0.354	4.263	0.228	1.860	3.053	1.226	1.942	2.125	1.617	2.573	0.584	0.961
	P* value	0.018	0.455	0.754	0.116	0.638	0.123	0.647	0.013	0.296	0.191	0.694	0.430	0.908	0.419
Larger Diff(V_CBCT,V_pCT) (20 cases)	pCT contours vs. CBCT contours	2.991	13.634	1.004	9.730	0.389	6.517	6.834	2.891	2.122	3.548	1.983	4.110	0.985	2.426
	dpCT contours vs. CBCT contours	3.058	13.336	0.866	9.089	0.503	7.253	6.163	2.622	1.827	4.013	1.752	4.300	0.683	2.310
	sCT contours vs. CBCT contours	0.714	6.629	0.404	4.766	0.862	3.039	5.130	1.280	1.933	2.067	1.809	3.226	0.566	2.209
	P* value	0.001	< 0.001	0.166	0.051	0.536	0.011	0.242	0.014	0.640	0.128	0.902	0.381	0.510	0.714

*P was calculated by comparing the dose metric errors of the dpCT contours vs. CBCT contours and of the sCT contours vs. CBCT contours according to paired sample t tests
\(Diff(V_{CBCT} ,V_{pCT} ) = \frac{{|V_{CBCT} - V_{pCT} |}}{{MIN(V_{CBCT} ,V_{pCT} )}} \times 100\%\)

ISSN: 1748-717X