Intensity-modulated radiation therapy(IMRT) is currently the main treatment method for nasopharyngeal carcinoma. During radiotherapy for nasopharyngeal carcinoma, factors such as body mass reduction, tumor regression, and organ displacement at risk can affect the precise implementation of radiation therapy. Applying adaptive radiotherapy (ART) technology to optimize the treatment plan at the appropriate timing can reduce the adverse effects caused by the above factors and enhance the accuracy of radiotherapy. There are no uniform standards for the necessity, timing, and case selection of ART. In this review, the research progress of ART in the radiotherapy of nasopharyngeal carcinoma in recent years was reviewed to provide a reference for further clinical application of ART in nasopharyngeal carcinoma.

Objective To compare biomechanical characteristics of external fixator, Kirschner’s wire, elastic stable intramedullary nailing (ESIN) for fixing proximal humeral fractures in children by finite element method.Methods The CT scanning data from the healthy humerus of an 8-year-old patient with proximal humeralfractures were collected, and the image data were imported in Mimics 21. 0 to establish the rough humeralmodel, which was imported in Geomagic 2013 to construct the three-dimensional (3D) model of cancellous and cortical bones of the humerus. After the model was assembled with 3 fixators ( external fixator, Kirschner’swire, ESIN), it was imported in ANSYS 2019 to simulate the upper limb under quiet, abduction, adduction, flexion, extension, external rotation, internal rotation working conditions. The maximum displacement of the distal humerus, the maximum stress of the fixture, and the maximum displacement of the distal fracture surface were analyzed. Results The minimum values of the maximum displacement of the distal humerus in models fixed by external fixator, Kirschner’s wire, ESIN appeared under extension (2. 406 mm), external rotation (0. 203 mm), external rotation (0. 185 mm) working conditions, respectively. Conclusions External fixator is the most unstable fixation of proximal humeral fractures in children, and the biomechanical performance of ESIN is better than that of external fixator and Kirschner’s wire fixation