Dosimetric comparison using different multileaf collimeters in intensity-modulated radiotherapy for upper thoracic esophageal cancer

Table 4 Comparisons of the DVH-based parameters of OARs in the present study (n = 10).

DVH-based parameters	MLC leaf width (mm)	mean ± SD	p value
*Spinal cord*
Dmax (cGy)	10	4288.5 ± 333.9	0.20
	4	4159.1 ± 422.5
D₅ (cGy)	10	3404.5 ± 374.4	0.021
	4	3260.3 ± 374.0
gEUD (cGy)	10	1849.2 ± 297.6	0.049
	4	1815.1 ± 281.7
*Total lungs*
V₅ (%)	10	43.2 ± 6.9	0.48
	4	42.9 ± 6.6
V₁₀ (%)	10	34.0 ± 6.7	0.004
	4	33.2 ± 6.5
V₂₀ (%)	10	16.6 ± 4.7	0.004
	4	16.0 ± 4.6
V₃₀ (%)	10	5.8 ± 2.3	0.09
	4	5.4 ± 2.0
MLD (cGy)	10	887.9 ± 172.1	0.005
	4	866.2 ± 174.1
gEUD (cGy)	10	956.8 ± 171.0	0.017
	938.6 ± 175.2

DVH: dose volume histogram; OARs: organs at risk; MLC: multileaf collimator; Dmean and Dmax: average and maximum irradiation dose; D₅: irradiation dose received by the 5% of volume of OAR; gEUD: generalized equivalent uniform dose; V₅,₁₀,₂₀,₃₀: the volume of total lungs receiving the dose of 5, 10, 20 and 30 Gy respectively; MLD: mean lung dose.

ISSN: 1748-717X