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Table 4 Comparison of delivery efficiency in all four radiotherapy plan groups

From: Single arc volumetric-modulated arc therapy is sufficient for nasopharyngeal carcinoma: a dosimetric comparison with dual arc VMAT and dynamic MLC and step-and-shoot intensity-modulated radiotherapy

  VMAT1 VMAT2 dIMRT ssIMRT p GLM-u p VMAT1 -VMAT2 p VMAT1 -dIMRT p VMAT1 -ssIMRT p VMAT2 -dIMRT p VMAT2 -ssIMRT p dIMRT -ssIMRT
MUs 1232.1 ± 146.2 1349.9 ± 133.8 1292.2 ± 120.7 1090.2 ± 91.1 <0.001 0.001 0.067 <0.001 0.079 <0.001 <0.001
Time (min) 2.7 ± 0.2 3.9 ± 0.3 5.7 ± 0.2 14.1 ± 1.0 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Mean dose rate (MU/min) 494.0 ± 38.6 379.6 ± 30.1 249.8 ± 17.9 86.6 ± 5.1 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Control points 161.4 ± 13.1 187.0 ± 30.9 126.6 ± 10.2 138.0 ± 10.4 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.223
plan calculation time (hour) 5.6 ± 1.4 4.8 ± 1.2 0.8 ± 0.3 0.8 ± 0.4 <0.001 0.092 <0.001 <0.001 <0.001 <0.001 0.945
  1. GLM-u: general linear model-univariate; VMAT1: single arc VMAT, VMAT2: dual arc VMAT; dIMRT: dynamic MLC IMRT; ssIMRT: step-and-shoot IMRT. “Bold numbers” means that p value has a statistically significance.