Dynamic MR Based Analysis of Tumor Movement in Upper and Mid Lobe Localized Lung Cancer

Background and purpose: Tumor motion is a very important factor in the radiotherapy of lung cancer. Uncertainty resulting from tumor movement must be considered in 3D therapy planning especially in case of IMRT or stereotactic therapy. The aim of our dynamic MR based study was to detect tumor movements in upper and mid lobe lung tumors. Patient and methods: Twenty-four patients with newly diagnosed stage II-IV lung cancer were enrolled into the study. According to tumor localization in the right S1–S3 segments 9, in the right S4–S6 segments 2, in the left S1–S3 segments 9 and in the left S4–S6 segments 4 lesions were detected. In normal treatment position individual dynamic MR examinations were performed in axial, sagittal and coronal planes (100 slices/30 sec). For tumor motion analysis E-RAD PAC's software was used. Results: Movements of the tumor under normal breathing conditions were registered in the three main directions. The mean antero-posterior deviation was 0,109 cm (range: 0,063 cm–0,204 cm), the mean medio-lateral deviation was 0,114 cm (range: 0,06 cm– 0,244 cm). The greatest deviation was measured in cranio–caudal direction (mean: 0,27 cm, range: 0,079 cm– 0,815 cm). The mean direction independent deviation was 0,18 cm (range: 0,09 cm– 0,48 cm). Conclusion: Dynamic MR is a sensitive and well tolerated method for tumor motion monitoring in high precision 3D therapy planning of lung cancer patients. Our results demonstrate that tumors located in the upper and mid lobes have moderate breath synchronous movements. The greatest deviation occur in cranio–caudal direction.