Normal lung sparing Tomotherapy technique in stage III lung cancer

Radiation Oncology

Table 4 Comparison of correlation coefficient between parameters related with planning target volume (PTV) and lung

Parameters	Lung	L-IMRT	p ^c	TH-IMRT	p ^c	TD-IMRT	p ^c
PTV	NTCP	−0.309	0.385	−0.261	0.467	−0.442	0.200
	D_mean	−0.309	0.385	−0.261	0.467	−0.442	0.200
	V₅	−0.273	0.446	−0.321	0.366	−0.406	0.244
	V₁₀	−0.236	0.511	−0.224	0.533	−0.345	0.328
	V₁₅	−0.273	0.446	−0.358	0.310	−0.539	0.108
	V₂₀	−0.272	0.446	−0.321	0.366	−0.406	0.244
	V₃₀	−0.236	0.511	−0.224	0.533	−0.345	0.328
	V₄₀	−0.297	0.405	−0.152	0.676	−0.4303	0.215
PTV length^a	NTCP	0.663	0.037	0.802	0.005	0.632	0.049
	D_mean	0.663	0.039	0.802	0.005	0.632	0.049
	V₅	0.657	0.039	0.687	0.028	0.523	0.121
	V₁₀	0.839	0.002	0.729	0.017	0.498	0.143
	V₁₅	0.851	0.002	0.802	0.005	0.644	0.044
	V₂₀	0.821	0.004	0.815	0.004	0.729	0.017
	V₃₀	0.547	0.102	0.711	0.021	0.553	0.097
	V₄₀	0.322	0.364	0.778	0.008	0.505	0.137
PTV ∩ Lung^b	NTCP	0.067	0.855	0.103	0.777	−0.079	0.829
	D_mean	0.067	0.855	0.103	0.777	−0.079	0.829
	V₅	0.103	0.777	0.152	0.676	0.115	0.751
	V₁₀	0.055	0.881	−0.018	0.960	−0.139	0.701
	V₁₅	0.03	0.934	−0.018	0.960	−0.127	0.726
	V₂₀	−0.055	0.881	−0.042	0.907	−0.103	0.777
	V₃₀	−0.018	0.960	0.115	0.751	−0.152	0.676
	V₄₀	−0.03	0.934	0.273	0.446	0.018	0.960

PTV planning target volume, NTCP normal tissue complication probability, V _D the percentage of organ volume receiving D Gy or higher, Dmean mean dose
^aPTV length means the superior-inferior length of the PTV
^bPTV ∩ Lung means the PTV volume overlapping with the normal lung
^cAll p values were calculated by the Spearman correlation test

ISSN: 1748-717X