Table 4.

The previous studies on grade 4 or 5 pneumonitis after radiation therapy in patients with interstitial pneumonitis

	Number of patients	Treatment	Median total dose	Pneumonitis
Yamaguchi et al. [7]	16	SBRT	48	3 (19 %)
Yamashita et al. [8]	13	SBRT	48	7 (53.8 %)
Lee et al. [9]	15	Conformal RT	56.9	5 (33.3 %)
Present study	16	PBT	80 Gy (RBE)	1 (6.3 %)

Abbreviations: SBRT stereotactic body radiotherapy, RT radiotherapy, RBE relative biological dose effectiveness, PBT proton beam therapy