Dosimetric analysis and comparison of reduced longitudinal cranial margins of VMAT-IMRT of rectal cancer

Radiation Oncology

Table 3 Relative dose parameters of selected organs at risk for different cranial PTVs of rectal cancer

Structure	Parameter	PTV0	PTV-1	p-value	PTV-2	p-value	PTV-3	p-value
Structure		Volume (%)
Bone	V10	87	84	0.007	78	0.005	70	0.005
	V20	69	66	0.005	62	0.005	55	0.005
	V30	44	41	0.007	39	0.005	33	0.005
	V40	29	27	0.017	24	0.007	20	0.005
Darm loops	V10	21	18	0.008	14	0.008	10	0.008
	V15	19	16	0.008	13	0.008	8	0.008
	V20	14	11	0.008	09	0.008	06	0.008
	V25	9	7	0.008	5	0.008	4	0.008
	V30	6	5	0.008	3	0.008	3	0.008
	V35	4	3	0.028	2	0.028	2	0.018
	V40	3	2	0.043	2	0.028	1	0.028
	V45	2	2	0.018	2	0.028	1	0.028
	V50	1	0	0.612	0	0.176	0	0.028
Peritoneal space	V10	71	58	0.005	47	0.005	37	0.008
	V15	61	51	0.005	42	0.005	33	0.005
	V20	48	42	0.005	34	0.005	28	0.005
	V25	36	32	0.005	27	0.005	22	0.005
	V30	27	24	0.005	21	0.005	18	0.005
	V35	22	20	0.005	17	0.005	15	0.005
	V40	18	17	0.005	15	0.005	13	0.005
	V45	16	15	0.005	13	0.005	12	0.005
	V50	08	07	0.114	06	0.005	06	0.005

Bold values: statistic significant versus PTV0. PTV-1 = PTV minus 1 cm on cranial site. p-value = PTV1,2,3 vs. PTV0

ISSN: 1748-717X