Intensity-modulated proton and carbon-ion radiotherapy using a fixed-beam system for locally advanced lung cancer: dosimetric comparison with x-ray radiotherapy and normal tissue complication probability (NTCP) evaluation

. To assess the dosimetric consequences and the normal tissue complication probability (NTCP) for the organs at risk (OARs) in intensity-modulated particle radiotherapy of proton (IMPT) and carbon-ion (IMCT) using a fixed-beam delivery system when compared with intensity-modulated photon radiotherapy (IMRT) for locally advanced small-cell lung cancer.