Respiratory gating and radiotherapy

In recent years, radiotherapy techniques had been improved significantly, but it is still not so satisfied in the conformal treatment of the lesions that affected by respiratory movement. Respiratory gating is one of the several methods that can compensate the movement of tumors that caused by respiratory. Although both internal and external markers can be used in the gating radiotherapy, it is obvious that internal markers and tumors have good consistency, while external markers and tumors have different consistency:more consistent in abdomen than in thorax. After applying these gating methods, we can compensate the influence of respiratory, delineate the target volume more accurately, and reduce the potential adverse reactions of radiotherapy.