RESUMO
PURPOSE: It is very important to remove or to reduce the effect of organ motion due to respiration in stereotatic radiosurgery of lung. This study reports the effectiveness of the breath hold technique with a ABC for reducing the breathing effect. MATERIALS AND METHODS: Whole body stereotactic frame (Elekta, Sweden) was used for lung SRS. Patients who have tumor motion range larger than 10 mm from fluoroscopic observation were selected to apply a ABC. Seventeen patients were enrolled in this study. Passive breath hold is possible with our ABC. Automatic breath hold was set at 80% of deep inspiration. Breath hold time was 25~30 seconds depending on the patients. Three consecutive CT scans were performed as indicated in Asan Medical Center SRS procedure for each patients. Lung volume and PTV differences between with breath hold and free breath were examined for 5 patients. RESULTS: The breath hold technique with ABC could be applied for 15 patients. Inter-, intra-treatment organ motion with ABC showed 1.5 mm, while it was 2.3 mm with abdomen compress. When with breath hold technique, PTV and CTV was reduced 33.7% and 45.4%, respectively, and lung volume was increased 32.3 % compared to conventional SRS method. CONCLUSION: Better target localization could be achieved with breath hold technique in lung SRS. Tumor motion could be minimized and relative lung volume irradiation could be reduced