Re-irradiating spinal column metastases using IMRT and VMAT with and without flattening filter - a treatment planning study

Table 3 Comparison of plan delivery and evaluation of dosimetry

	IMRT			VMAT
Parameter	FF	FFF	p	FF	FFF	p
Delivery time (s)	557 ± 41	438 ± 23	<0.01	216 ± 15	163 ± 5	<0.01
Monitor units per Gy	381 ± 25	448 ± 43	<0.01	391 ± 29	429 ± 37	0.02
Measured peripheral dose (mGy)	8.6 ± 1.4	5.8 ± 1.2	<0.01	7.0 ± 1.0	4.8 ± 1.0	<0.01
Calculated peripheral dose (mGy)	4.7 ± 1.3	4.6 ± 1.5	0.51	5.7 ± 1.4	5.6 ± 1.4	0.24
Passing rate of γ (%)	97.6 ± 1.1	97.4 ± 1.2	0.51	98.1 ± 1.1	97.9 ± 1.0	0.37

Mean values and standard deviation of delivery time, monitor units, measured and calculated peripheral doses and result of the gamma evaluation for the four different planning techniques averaged over all ten patients. P-values for comparison of FF and FFF are calculated separately for IMRT and VMAT. Bold values indicate significantly superior values

ISSN: 1748-717X