The present invention provides a radiotherapy system that can monitor a target location in real time. The radiotherapy system includes a remote control system operable to actuate a real-time image capturing device to acquire images in real time for monitoring the target location. The system also includes an image registration system that can register the acquired image with an image previously captured for the treatment plan, whereby it can be determined whether the patient's tumor is in the beam's eye view of the treatment plan. By confirming that the tumor is in the range of the beam's eye view, the accuracy of the treatment can be improved, and the irradiated area can be reduced, which makes the radiation treatment safer.