Assessment of the modulation degrees of intensity-modulated radiation therapy plans

Radiation Oncology

Table 4 Correlations between global gamma passing rates with various gamma criteria and the modulation indices for intensity modulated radiation therapy plans of Trilogy (p ≤ 0.05)

	3%/3 mm		2%/2 mm		2%/1 mm		1%/2 mm
	r _s	p	r _s	p	r _s	p	r _s	p
MI	MapCHECK2
MI_s	−0.398	< 0.001	−0.386	< 0.001	− 0.347	< 0.001	− 0.323	0.001
MI_a	−0.302	0.002	−0.305	0.002	−0.397	< 0.001	− 0.210	0.034
MI_{c, IMRT}	−0.315	< 0.001	−0.320	< 0.001	− 0.400	< 0.001	− 0.230	0.006
MCS	0.391	< 0.001	0.347	< 0.001	0.377	< 0.001	0.272	0.004
PA	−0.482	< 0.001	− 0.428	< 0.001	−0.655	< 0.001	− 0.286	< 0.001
PI	−0.452	< 0.001	− 0.427	< 0.001	− 0.475	< 0.001	− 0.348	< 0.001
PM	−0.431	0.001	−0.420	0.001	−0.455	< 0.001	− 0.357	0.020
ArcCHECK
MI_s	−0.271	0.006	−0.346	< 0.001	−0.355	< 0.001	–	–
MI_a	−0.364	< 0.001	−0.455	< 0.001	− 0.456	< 0.001	−0.273	0.006
MI_{c, IMRT}	−0.375	< 0.001	−0.471	< 0.001	− 0.472	< 0.001	−0.281	0.004
MCS	0.426	< 0.001	0.589	< 0.001	0.660	< 0.001	–	–
PA	−0.505	< 0.001	− 0.667	< 0.001	−0.739	< 0.001	− 0.370	< 0.001
PI	−0.395	< 0.001	− 0.581	< 0.001	−0.663	< 0.001	–	–
PM	−0.410	< 0.001	−0.607	< 0.001	− 0.671	< 0.001	−0.198	0.046

Note: r_s Spearman’s rho, MI_s Modulation index considering multi-leaf collimator speed, MI_a Modulation index considering multi-leaf collimator acceleration, MI_{c, IMRT} Modulation index considering multi-leaf collimator acceleration and field aperture irregularity for intensity modulated radiation therapy, MCS Modulation complexity score, PA Plan-averaged beam area, PI Plan-averaged beam irregularity, PM Plan-averaged beam modulation

ISSN: 1748-717X