Four-Dimensional Computed Tomography Based Respiratory-Gated Radiotherapy with Respiratory Guidance System: Analysis of Respiratory Signals and Dosimetric Comparison

Table 3

Comparison of dose volume histogram (DVH) between plans with free breathing CT and 4D MIP CT.

(a) Liver

	Free breathing CT plan (cc)	MIP based plan (cc)	P value
	78.75 ± 3.51	68.06 ± 6.68	0.024
	65.16 ± 7.83	54.24 ± 10.45	0.030
	43.84 ± 12.80	35.22 ± 14.11	0.048
	32.81 ± 12.68	27.34 ± 14.68	0.117
	25.79 ± 11.47	21.53 ± 13.61	0.069
	19.39 ± 9.71	16.06 ± 11.21	0.067

(b) Ipsilateral lung

	Free breathing CT plan	MIP based plan	P value
	48.97 ± 15.37	40.74 ± 11.07	0.051
	37.71 ± 17.89	29.31 ± 15.22	0.035
	23.02 ± 11.20	16.03 ± 8.75	0.018
	15.19 ± 9.24	8.94 ± 5.46	0.034
	9.18 ± 5.88	4.90 ± 3.18	0.035
	1.64 ± 1.93	1.19 ± 1.35	0.287

(c) Contralateral lung

	Free breathing CT plan	MIP based plan	P value
	13.65 ± 12.29	8.91 ± 20.58	0.140
	2.63 ± 4.90	1.01 ± 2.08	0.160
	0	0	—
	0	0	—
	0	0	—
	0	0	—

Volume receiving 5 Gy.
^†Volume receiving 10 Gy.
^‡Volume receiving 20 Gy.
Volume receiving 30 Gy.
Volume receiving 40 Gy.
Volume receiving 50 Gy.