Development of multimodal neuroimaging markers for neurological disorders - Part 2.

The second part of the special issue includes 5 articles. Among them, two evaluate the treatment effect using imaging techniques including fMRI and optical positioning system (OPS), and three address the issues related to development and application of new methods for improving the accuracy and efficiency of neuroimaging data analysis. Tumour tracking and radiotherapy are the most implemented technique in the treatment of brain cancer. However, patient-positioning accuracy continues to be an inevitable question in radiotherapy. In order to improve treatment efficacy, Zhou et al., reported a study that focused on the comparison of Cone Beam CT and OPS positioning in radiotherapy of phantom experiment [1]. To illustrate the positioning accuracy of OPS, a clinical trial using EPID was designed, and the comparative results of patient-positioning accuracy between using conventional positioning method and OPS was reported. In the end, the authors gave a report about the influence to the radiotherapy caused by the deviation of positioning in the radiotherapy and the OPS as a novel image guidance technology. The study concluded that, OPS had higher precise than conventional positioning methods, compartively fast, and efficient positioning method with respect to the CBCT guidance system. On the other hand, Li et al., investigated the dose parameter comparison for hippocampus protection between dual arc VMAT and 7F-IMRT for patients with brain metastases from lung cancer under the whole brain radiotherapy [2]. In this study, a region with a margin of 4 mm around hippocampus was proposed to be regarded as a virtual organ at risk (OAR) to reduce the dose received by hippocampus, which ensures that, the patients do not lose learning and memory functions and enhance their life qualities [3]. Two types of radiotherapy plans (i.e., dual arc VMAT and 7F-IMRT) were designed. An analysis and comparison of DVH curves was made for two plans and the statistical analyses were performed to compare dose parameters. The dose parameters include CI and HI of the target, the maximum dose of OARs (i.e., hippocampus, eyes, lens and optic nerve), MU, and treatment time [4].