Significant reductions in heart and lung doses using semi lateral decubitus techniques for left sided breast cancer patients: A comparative dosimetric study with supine techniques

Peer review under responsibility of Alexandria University Faculty of Medicine.

Available online 9 January 2017

Figures & data

Figure 1 Standard breast board (A) & special breast board (B).

Figure 2 Room eye view shows PTV in yellow, ipsilateral lung in red, heart in green, contra lateral lung in brown and contra lateral breast in blue.

Figure 3 DVH for PTV in yellow, heart in green and Ipsilateral lung in red comparing the target coverage and sparing of ipsilateral lung & heart in supine (A), semi-lateral (B) and semi-lateral decubitus + breath hold techniques (C).

Table 1 Comparison of the average of PTV DVPs in cGy for left sided breast cancer patients irradiated by three different decubitus techniques. P values for the differences between the plans are also shown.

PTV DVPs	Plan 1	Plan 2	Plan 3	Differences	Differences	Differences
				Plan 1/2	Plan 1/3	Plan 2/3
				P values	P values	P values
PTV D95%	4826.22	4843.58	4829.44	14.50	1.70	16.22
				0.304	0.769	0.354
PTV Dmax	5466.98	5479.60	5481.12	13.20	14.40	1.20
				0.561	0.108	0.939
HI	1.07	1.06	1.06	0.004	0.01	0.006
				0.444	0.109	0.290

Table 2 Comparison of the average of heart and lung DVPs in cGy and in% for left sided breast cancer patients irradiated by three different decubitus techniques. P values for the differences between the plans are also shown.

OAR DVPs	Plan 1	Plan 2	Plan 3	Reduction%	Reduction%	Reduction%
				Plan 1/2	Plan 1/3	Plan 2/3
				P values	P values	P values
Heart V5Gy	8.9	5.13	1.81	−52	−76	−62
				<0.001	<0.001	<0.001
Heart V10Gy	5.73	2.47	0.66	−64	−72	−70
				<0.001	<0.001	<0.001
Heart V25Gy	3.05	1.02	0.19	−73	−96	−87
				<0.001	<0.001	<0.001
Heart V30Gy	2.27	0.78	0.13	−75	−97	−87
				<0.001	<0.001	<0.001
Heart mean dose	304.45	183.34	119.8	−35	−54	−27
				<0.001	<0.001	<0.001
Heart max dose	4552	3536	2006	−25	−57	−38
				<0.001	<0.001	<0.001
Ipsilateral lung V20Gy	18.10	11.29	10.08	−16	−25	−13
				0.001	<0.001	0.003
Ipsilateral lung mean dose	718.50	628.83	569.16	−15	−14	−5
				0.007	<0.001	0.006
Contralateral lungV20Gy	0.16	0.16	0.15	−12	−20	−11
				0.972	0.659	0.700
Contralateral lung mean dose	30.5	27.39	26.23	−37	−17	−32
				0.449	0.572	0.950

Percent of reduction is calculated as new number – original number/original number × 100.