Table 3.

Maximum doses received on the photon SBRT, PSPT, and IMPT plans

Critical normal structures	Cases	Mean maximum dose received on photon SBRT plan, Gy (SE)	Mean maximum dose received on PSPT plan, Gy (SE)	p*	Mean maximum dose received on IMPT plan, Gy (SE)	p†	p‡
Aorta	11	34.3 (3.8)	27.9 (5.3)	0.02	25.5 (5.7)	0.014	0.292
Brachial plexus	6	24.1 (5.3)	11.1 (2.8)	0.01	7.0 (2.8)	0.006	0.007
Bronchial tree	8	22.9 (4.3)	18.2 (4.4)	0.221	13.9 (4.1)	0.014	0.093
Esophagus	7	27.2 (5.7)	25.8 (3.6)	0.698	15.6 (4.1)	0.005	0.019
Heart	4	45.1 (8.8)	25.5 (6.5)	0.036	23.6 (7.3)	0.032	0.202
Pulmonary vessels	7	36.2 (3.4)	24.3 (2.7)	0.002	18.0 (4.7)	0.003	0.115
Spinal cord	9	20.7 (1.0)	17.4 (1.1)	0.02	12.6 (1.3)	<0.001	0.006
Trachea	3	18.4 (5.3)	19.6 (5.0)	0.909	13.5 (4.6)	0.598	0.215

Abbreviations: IMPT = intensity-modulated proton therapy; PSPT = passive-scattering proton therapy; SBRT = stereotactic body radiation therapy; SE = standard error.

^*Photon SBRT vs PSPT

^†Photon SBRT vs IMPT

^‡PSPT vs IMPT