Comparison of therapeutic dosimetric data from passively scattered proton and photon craniospinal irradiations for medulloblastoma

Table 4 Dose volume histogram (DVH) analysis for photon and proton craniospinal irradiation (n = 18)

Structure, DVH dose level (Gy)	Photons		Protons		P value, Wilcoxian Signed Rank test	Significance level	Sequential Bonferroni
Structure, DVH dose level (Gy)	Mean	SD	Mean	SD	P value, Wilcoxian Signed Rank test	Significance level	Sequential Bonferroni
Esophagus
20	65.87	23.54	3.89	7.68	9.82E-05	<0.01	†
15	96.68	5.12	8.73	12.53	9.80E-05	<0.01	†
10	98.09	3.26	14.76	16.59	9.75E-05	<0.01	†
5	99.61	0.98	24.67	21.28	9.80E-05	<0.01	†
Heart
20	2.80	4.58	0.03	0.08	2.51E-04	<0.01	†
15	42.49	16.98	0.15	0.23	9.82E-05	<0.01	†
10	56.77	11.12	0.53	0.62	9.82E-05	<0.01	†
5	60.68	11.30	1.31	1.28	9.82E-05	<0.01	†
Kidneys
20	2.03	1.91	0.60	0.82	3.15E-03	<0.01	†
15	4.11	2.81	2.49	2.34	1.07E-03	<0.01	†
10	5.92	3.68	5.53	4.70	2.50E-01	NS	—
5	8.89	4.95	10.58	7.95	6.24E-01	NS	—
Liver
20	3.09	3.17	0.08	0.15	9.82E-05	<0.01	†
15	14.69	4.22	0.27	0.30	9.82E-05	<0.01	†
10	22.55	1.99	0.61	1.05	9.82E-05	<0.01	†
5	24.78	3.95	1.10	0.75	9.82E-05	<0.01	†
Lungs
20	3.07	2.14	2.27	1.92	3.54E-02	< 0.05	*
15	6.03	2.92	4.87	3.24	6.14E-03	< 0.01	†
10	8.35	3.52	7.66	4.32	7.23E-02	NS	—
5	11.69	4.51	11.31	5.52	1.53E-01	NS	—
Thyroid
20	11.91	21.19	0.00	0.00	6.10E-05	<0.01	†
15	66.16	30.19	0.00	0.00	9.80E-05	<0.01	†
10	80.97	21.53	0.00	0.00	9.48E-05	<0.01	†
5	92.50	10.68	0.51	0.76	9.65E-05	<0.01	†

Note: The table lists mean V₂₀, V₁₅, V₁₀, and V₅ and standard deviation (SD) values for the esophagus, heart, kidneys, liver, lungs, and thyroid. Statistical results from the Wilcoxon signed rank test (i.e., p-value for 1-tailed Wilcoxon signed rank test) are listed. Results from the sequential Bonferroni procedure are also included; † and * indicate differences were significant at the 0.01 and 0.05 levels, respectively.
For this study 5, 10, 15, and 20 Gy are equivalent to 21.4%, 42.7%, 64.1%, and 85.5% of the prescribed dose, respectively.