A study of X-ray volume imaging system in image guided radiotherapy with variable gantry rotations

Purpose: The main purpose of this work is to investigate the optimal usage of X-ray volume imaging (XVI) system in image-guided radiotherapy with different gantry rotations in order to reduce scanning volume. Methods: A total of 60 scans of 16 individual patients with breast and head and neck cancer were used in this study. Full and partial gantry rotations were performed at the same time with same setup on the couch using XVI system by changing the preset information. The reference and localization images were matched with this system. The set up errors were evaluated with XVI software. Results: Variation in translational errors with full and half gantry rotations in breast cases were u003c2 mm in 86.6% of measurements. Similarly, variations between full and partial gantry rotations in head and neck cases were u003c1 mm in 95.5% of measurements. Results showed almost similar translational and rotational shifts in both full and partial gantry rotations in the majority of the cases. Conclusion: Based on selected cases in this study, partial rotation of the gantry for acquiring 3D cone beam computerized tomography (CBCT) is very useful option in reducing scanning volume and total treatment time in IGRT. However, the use of partial rotation of the gantry depends on patient thickness and area to be reconstructed to track anatomical changes near to the target.