. Author manuscript; available in PMC: 2014 Aug 4.

Published in final edited form as: Int J Radiat Oncol Biol Phys. 2009 Jun 1;74(2):616–622. doi: 10.1016/j.ijrobp.2009.01.001

Table 1.

RRR of SMN developing, defined as ratio of ERR_proton to ERR_IMRT, in 3 patients treated for prostate cancer

	ERR _T
		Patient 1 (small)		Patient 2 (medium)		Patient 3 (large)
Organ	ERR/Sv	Proton therapy	IMRT	Proton therapy	IMRT	Proton therapy	IMRT
Colon	0.51	2.53	3.13	2.25	2.73	2.39	3.15
Lung	0.26	0.04	0.02	0.05	0.02	0.05	0.02
Stomach	0.17	0.03	0.02	0.04	0.02	0.05	0.02
Bladder	0.40	4.98	8.96	3.99	6.92	7.93	10.70
Liver	0.26	0.05	0.03	0.07	0.03	0.07	0.03
Thyroid	0.04	0.00	0.00	0.01	0.00	0.01	0.00
Bone marrow	1.33	0.50	1.04	0.63	1.00	0.71	1.11
Remainder	0.18	0.09	0.19	0.11	0.18	0.13	0.20
ERR _modality	—	8.2	13.4	7.1	10.9	11.3	15.2
RRR	—	0.61		0.66		0.74

Abbreviations: RRR = ratio of excess relative risk; SMN = secondary malignant neoplasm; ERR_proton = excess relative risk of a radiation-induced cancer developing after exposure to proton therapy; ERR_IMRT = excess relative risk of a radiation-induced cancer developing after exposure to intensity-modulated X-ray therapy; ERR_T = excess relative risk of a radiation-induced cancer developing in tissue T; IMRT = intensity-modulated X-ray therapy; ERR_modality = excess relative risk for each modality (proton therapy or IMRT).