Simultaneous integrated boost radiotherapy for bilateral breast: a treatment planning and dosimetric comparison for volumetric modulated arc and fixed field intensity modulated therapy

Table 3 Summary of delivery parameters and pre-treatment dosimetric tests

Delivery parameters
2 Gy/fraction	RapidArc		IMRT
Monitor Units (MU)	796 ± 121		1398 ± 301		p < 0.01
MeanDose Rate (MU/min)	378 ± 46		600 fixed		-
Mean MU/ ^°	1.1 ± 0.2		-		-
Beam on time (min)	2.30 ± 0.01		2.23 ± 0.40		p = 0.14
Treatment time (min)	3.00 ± 0.08		11.45 ± 2.05		p < 0.01
Pre-treatment Quality Assurance
	RapidArc		IMRT
	GLAaS	PTW729	GLAaS	PTW729
GAI (3% 3 mm) (%)	98.8 ± 1.3 ^a	98.8 ± 1.3 ^a	99.1 ± 1.5 ^a	99.5 ± 1.3 ^a
GAI (2% 3 mm) (%)	97.0 ± 2.8 ^a	97.0 ± 2.8 ^a	97.2 ± 4.3 ^a	98.4 ± 3.0 ^a
GAI (2% 2 mm) (%)	93.0 ± 5.0	93.0 ± 5.0	94.4 ± 4.3	96.3 ± 4.3

Data are reported as mean ± 1 standard deviation computed over the cohort of 10 patients.
GAI is the Gamma Agreement Index, percentage of field area of percentage of measured points fulfilling the criteria γ <1.
* p < 0.05; ** p < 0.01; ^a p < 0.05 w.r.t. GAI = 95%

ISSN: 1748-717X