Stereotactic body radiation therapy for non-small cell lung cancer using the non-coplanar radiation of Cyberknife and Varian linac

PURPOSE: This study aims to evaluate the planned dose of stereotactic body radiation therapy (SBRT) for treating early peripheral non-small cell lung cancer (NSCLC) using the non-coplanar radiation from Cyberknife andVarian linac. Moreover, this study investigates whether Cyberknife and Varian linac are qualified for non-coplanar radiation SBRT for treating early peripheral NSCLC, and which one is better for protecting organs at risk (OARs). METHODS: Retrospective analysis was performed based on the Cyberknife radiation treatment plans (RTPs) and Varian Eclipse RTPs of 10 patients diagnosed with early peripheral NSCLC. The dose distributions in the target and OARs were compared between the RTPs of Cyberknife and Varian Eclipse using Mim medical imaging software. RESULTS: For PTV, no significant difference in D-98 and D-95 between the Cyberknife and Eclipse was observed (t = -0.35, -1.67, P > 0.05). The homogeneity indexes (HIs) of Cyberknife plans are higher (t = 71.86, P < 0.05) than those of Eclipse plans. The V-10, V-15, V-20, V-25, V-30 and D-mean of the lung with NSCLC and the V-20 of the whole lung for Cyberknife were less than those for Eclipse (t = -4.73, -5.62, -7.75, -6.38, -6.89, -3.14, -7.09, respectively, P < 0.05). Cyberknife plans have smaller spinal cord D-max, trachea D-max, heart D-max, chest wall D-max (t = -2.49, -2.57, -3.71, -3.56, respectively, P < 0.05) and esophagus D-max (t = -1.95, P > 0.05) than Varian Eclipse plans. CONCLUSION: To fulfill SBRT by non-coplanar radiation, Cyberknife is recommended for the institutions equipped with Cyberknife, whileVarian linac can be applied for the institutions that have not adopted Cyberknife in clinical radiotherapy yet.