[Investigation of field width and pitch in tomotherapy treatment plans for brain metastases from lung cancer].

Tomotherapy plans were produced using a combination of field widths (1 cm, 2.5 cm and 5 cm) and pitches (0.15, 0.30, and 0.45) for seven patients with brain metastases from lung cancer, the plans were compared with dosimetric parameters, protection of organs at risk (OAR) dose and treatment times. All plans were defined that CTV with 30Gy and GTV 50 Gy by ten fraction synchronously. The results showed that the mean dose and CI for GTV was statistical difference (P = 0.002 1, P = 0.012 8), OARs were within the normal range, the treatment time increased inversely proportional to the jaw width, but had lesser impact on the pitch. This study showed plans produced with 5 cm jaw was an effective method for patients with brain metastases from lung cancer.