The purpose of this study was to evaluate setup uncertainties for brain sites with ExacTrac X‐Ray 6D system and to provide optimal margin guidelines. Fifteen patients with brain tumor were included in this study. Two X‐ray images with ExacTrac X‐Ray 6D system were used to verify patient position and tumor target localization before each treatment. The 6D fusion software first generates various sets of DRRs with position variations in both three translational and three rotational directions (six degrees of freedom) for the CT images. Setup variations (translation and rotation) after correction were recorded and corrected before treatment. The 3D deviations are expressed as . The random error , systematic error , and group systematic error for the different X‐ray were calculated using the definitions of van Herk.⁽¹⁾ Mean setup errors were calculated from X‐ray images acquired after all fractions. There is moderate patient‐to‐patient variation in the vertical direction and small variations in systematic errors and magnitudes of random errors are smaller. The global systematic errors were measured to be less than 2.0 mm in each direction. Random component of all patients are smaller ranging from 0.1–0.3 mm small. The safety margin (SM) to the lateral, is 0.5 mm and 2.6 mm for van Herk⁽¹⁾ and Stroom et al.,⁽²⁾ respectively, craniocaudal axis is 1.5 mm and 3.4 mm, respectively, and with respect to the antero–posterior axis, 2.3 mm and 3.9 mm. Daily X‐ray imaging is essential to compare and assess the accuracy of treatment delivery to different anatomical locations.PACS number: 87.55.D

Background: To report the efficacy of induction treatment (IT) protocol with concurrent radiochemotherapy in locally advanced non-small-cell lung cancer (NSCLC), and to analyze downstaging as a surrogate end point. Patients and methods: Patients with histo- or cytologically confirmed stage IIIA or IIIB NSCLC were treated according to an IT protocol followed by surgery. Downstaging was assessed for all resected patients. Results: In the period between February 1992 and July 2000, 92 patients were enrolled in the study (57 IIIA, 35 IIIB). Response was observed in 63 patients; 56 patients underwent radical resection. Patients downstaged to stage 0–I (DS 0–I) showed a statistically significant improved disease-free survival (26.2 months pStage 0–I versus 11.2 months pStage II–III; P = 0.0116) and overall survival (median 32.5 months pStage 0–I versus 18.3 months pStage II–III; P = 0.025). Patients with DS 0–I had a significantly lower probability (P = 0.0353) of developing distant metastases estimated in 0.2963 odds ratio. Conclusion: Neoadjuvant radiochemotherapy is feasible with good pathological DS results. Pathological downstaging was confirmed to have high predictive value. Its use is suggested in the short-term evaluation of induction protocols efficacy in locally advanced NSCLC.