Lack of dose dependency for radiation pneumonitis after chemoradiotherapy with the use of tomotherapy for lung cancer.

A 71-year-old man with stage IIB (Union for International Cancer Control, 8 edition) non-small cell lung cancer underwent intensity-modulated radiation therapy with a dose of 66 Gy administered in 33 fractions concomitant with carboplatin and paclitaxel therapy. On computed tomography after completion of radiation therapy, ground-glass opacity, which was larger on the contralateral side, was observed, but it was not observed in the high-dose area on the ipsilateral side. Although the adverse event theoretically shows dose dependency, it was finally diagnosed as radiation pneumonitis.