A retrospective study on improving the accuracy of radiotherapy for patients with breast cancer with lymph node metastasis using Styrofoam

FIGURE 1.

FIGURE 2.

FIGURE 3.

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FIGURE 5.

Target volume expansion boundary in the three-dimensional direction in 65 patients in the breast bracket and Styrofoam groups (mm)

		Styrofoam			Bracket
		X	Y	Z	X	Y	Z
Σ Systematic error	CROI	1.59	1.99	1.78	2.05	2.10	2.00
	SROI	1.23	1.23	1.36	1.32	1.16	1.75
σ Random error	CROI	1.47	1.46	1.46	1.39	1.57	1.57
	SROI	0.88	1.12	1.26	0.98	1.17	1.54
MPTV	CROI	5.01	5.99	5.47	6.10	6.34	6.10
	SROI	3.69	3.86	4.28	3.99	3.72	5.45

Comparison of clinical data between the two groups

Group	Styrofoam n = 36	Bracket n = 29	P-value
Age (x ± s, years)	48.34 ± 9.58	48.90 ± 10.92	0.837
Affected Side (n, %)			0.565
Left	20 (55.6)	11 (37.9)
Right	16 (44.4)	18 (62.1)
Type of operation (n, %)			0.053
Bcs	7 (16.7)	9 (31)
Rm	29 (83.3)	20 (69)
Stage (n, %)			0.146
II	7 (19.4)	4 (13.8)
III	26 (72.2)	20 (68.9)
IV	3 (8.4)	5 (17.3)

Comparison of setup errors of the two fixation methods in the chest wall target area and supraclavicular target area (mm,`x ± s)

Group	Styrofoam	Bracket	t	P-value
CROI (X)	1.59± 1.47	2.05 ± 1.64	2.516	0.012
(Y)	1.99 ± 1.46	2.10 ± 1.59	0.611	0.541
(Z)	1.78 ± 1.47	2.00 ± 1.58	1.235	0.218
SROI (X)	1.23 ± 0.88	1.32 ± 1.16	0.620	0.536
(Y)	1.23 ± 1.21	1.16 ± 1.17	−0.445	0.657
(Z)	1.36 ± 1.27	1.75 ± 1.55	2.003	0.046
CRTN (°)	0.48 ± 0.46	0.53 ± 0.43	1.033	0.302
SRTN (°)	0.47 ± 0.47	0.66 ± 0.59	2.760	0.006