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

Radiation Oncology

Table 3 Correlations between global gamma passing rates with various gamma criteria and the modulation indices for intensity modulated radiation therapy plans of TrueBeam STx (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
MapCHECK2
MI_s	− 0.241	0.016	− 0.200	0.046	–	–	–	–
MI_a	–	–	–	–	–	–	–	–
MI_{c, IMRT}	–	–	–	–	–	–	− 0.201	0.045
MCS	0.453	< 0.001	0.548	< 0.001	0.509	< 0.001	0.460	< 0.001
PA	−0.223	0.026	− 0.236	0.018	–	–	− 0.196	0.050
PI	−0.465	< 0.001	−0.591	< 0.001	− 0.550	< 0.001	− 0.474	< 0.001
PM	− 0.476	< 0.001	− 0.566	< 0.001	− 0.516	< 0.001	− 0.438	< 0.001
ArcCHECK
MI_s	− 0.375	< 0.001	− 0.341	0.001	−0.518	< 0.001	− 0.292	0.003
MI_a	−0.234	0.019	–	–	− 0.234	0.019	–	–
MI_{c, IMRT}	−0.225	0.025	–	–	−0.228	0.022	–	–
MCS	0.431	< 0.001	0.593	< 0.001	0.451	< 0.001	0.699	< 0.001
PA	−0.235	0.019	–	–	− 0.225	0.024	–	–
PI	−0.340	0.001	−0.545	< 0.001	−0.328	0.001	−0.677	< 0.001
PM	−0.369	< 0.001	−0.545	< 0.001	− 0.389	< 0.001	− 0.667	< 0.001

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