Table 1. Variations in TV, BP, and T in 4-dimensional computed tomography scans 1 and 2.

	TV (mL)		BP		T (s)*		Relative variation [(X2 – X1)/X1] (%)
Patient number	CT1	CT2	CT1	CT2	CT1	CT2	TV	BP	T
1	587	436	0.06	0.26	8.7	3.3	−26	333	−62
2	297	286	0.49	0.34	3.0	2.9	−4	−31	−3
3	144	170	0.36	0.32	2.1	2.4	18	−11	14
4	328	338	0.24	0.22	2.8	3.0	3	−8	7
5	310	467	0.12	0.19	4.4	4.4	51	58	0
6	328	352	0.14	0.04	2.7	2.5	7	−71	−7
7	369	526	0.03	0.03	4.2	4.4	43	0	5
8	442	618	0.28	0.15	4.4	5.0	40	−46	14
9	215	346	0.18	0.21	2.1	4.0	61	17	90
10	839	1087	0.39	0.26	6.9	6.9	30	−33	0
Range of variation							−26 to 61	−71 to 333	−62 to 90

Abbreviations: BP = breathing pattern; CT1 = first 4-dimensional computed tomography scan; CT2 = second 4-dimensional computed tomography scan; T = period; TV = tidal volume.

^*The averaged period was obtained from a Fourier analysis of patients' breathing waveforms.