Advanced nasopharyngeal carcinoma radiotherapy with volumetric modulated arcs and the potential role of flattening filter-free beams

Table 3 Comparison of OAR doses among the three techniques

OARs	RA-FFF(Gy)	RA(Gy)	IMRT(Gy)	p value	p ¹	p ²	p ³
Spinal cord D_1%	41.22 ± 2.51	39.58 ± 2.21	40.00 ± 1.46	0.061	—	—	—
Brain stem D_1%	55.58 ± 3.25	53.22 ± 3.35	52.82 ± 2.52	0.014	0.013	0.017	0.359
Optic nerve (right) D_1%	16.91 ± 22.14	17.93 ± 21.52	16.45 ± 19.50	0.007	0.059	0.959	0.059
Optic nerve (left) D_1%	15.26 ± 18.32	16.55 ± 17.28	14.15 ± 15.75	0.061	—	—	—
Len (right) D_1%	5.36 ± 2.65	5.74 ± 2.36	5.35 ± 2.54	0.236	—	—	—
Len (left) D_1%	5.11 ± 2.08	5.32 ± 1.83	4.90 ± 1.95	0.232	—	—	—
Larynx Dmean	32.55 ± 2.97	31.83 ± 2.69	35.40 ± 1.90	0.001	0.025	0.007	0.005
Oral cavity Dmean	34.12 ± 2.23	33.31 ± 1.90	33.52 ± 1.38	0.025	0.017	0.169	0.646
Parotid (right) Dmean	35.95 ± 4.32	34.00 ± 3.87	36.57 ± 4.15	0.001	0.005	0.445	0.005
Parotid (left) Dmean	34.67 ± 3.62	33.47 ± 3.16	35.36 ± 2.97	< 0.001	0.005	0.059	0.005
Normal tissue Dmean	16.24 ± 2.10	16.41 ±2.09	16.20 ± 2.04	0.150	—	—	—
Skin Dmean	17.24 ± 2.31	16.82 ± 2.27	16.75 ± 2.32	0.008	0.017	0.007	0.646

ISSN: 1748-717X