Noninvasive cardiac radioablation for ventricular tachycardia: dosimetric comparison between linear accelerator- and robotic CyberKnife-based radiosurgery systems

Table 1 Comparison of plan quality parameters between the LA- and CK-based systems for 13 clinical cases

No	PTV (cm³)	Coverage (%)	HI (Ratio)		CI (Ratio)		GI (Ratio)		GM (cm)		D_2cm (%)
No	PTV (cm³)	Coverage (%)	LA	CK	LA	CK	LA	CK	LA	CK	LA	CK
1	52.1	95.6	1.19	1.30	0.81	0.69	4.27	3.72	1.44	1.24	59.7	51.2
2	80.5	97.2	1.24	1.32	0.77	0.76	4.12	4.38	1.54	1.39	58.1	60.9
3	23.9	95.0	1.25	1.28	0.90	0.89	3.56	2.43	1.03	0.69	61.7	41.3
4	14.4	95.4	1.21	1.28	0.90	0.95	4.18	2.67	0.99	0.70	48.8	34.5
5	34.4	95.0	1.21	1.23	0.91	0.89	3.45	2.77	1.18	0.97	56.6	45.2
6	83.4	95.5	1.26	1.30	0.86	0.78	3.74	3.91	1.50	1.34	56.5	59.1
7	92.6	95.0	1.29	1.33	0.90	0.84	3.17	2.76	1.44	1.21	56.0	60.1
8	19.6	95.0	1.22	1.43	0.92	0.85	3.06	2.95	0.77	0.67	47.4	44.1
9	26.1	95.0	1.26	1.40	0.92	0.89	3.01	2.83	0.83	0.72	48.6	45.6
10	24.2	95.0	1.28	1.37	0.94	0.93	2.82	2.36	0.76	0.63	45.9	46.3
11	24.6	95.1	1.24	1.39	0.87	0.88	3.55	3.44	0.93	0.90	48.3	43.1
12	93.7	69.5	1.23	1.43	0.69	0.75	2.50	2.24	1.32	1.12	48.9	68.0
13	77.6	95.3	1.21	1.37	0.88	0.76	3.77	4.08	1.43	1.34	53.5	60.2
Mean ± SD	49.8 ± 31.0	93.0 ± 7.2	1.24 ± 0.03	1.34 ± 0.06	0.87 ± 0.07	0.84 ± 0.08	3.48 ± 0.55	3.12 ± 0.71	1.17 ± 0.29	1.00 ± 0.29	53.1 ± 5.3	50.8 ± 9.9
p-value*			< 0.001		0.093		0.031		< 0.001		0.423

CI conformity index, CK CyberKnife, D_2cm maximum dose 2 cm from the PTV in any direction, GI gradient index, GM gradient measure, HI homogeneity index, LA linear accelerator, PTV planning target volume
*Significance is tested using the paired-sample t-test, with p < 0.05 indicating statistical significance

ISSN: 1748-717X