1. A radiotherapy apparatus control apparatus comprising: a matching degree calculating section configured to calculate a plurality of matching degrees based on each of a template set and a plurality of transmission images imaged by using radiation transmitting through a specimen; a selecting section configured to select a template transmission image from the plurality of transmission images based on the matching degrees; and a template generating section configured to add a new template, which is generated based on said template transmission image, to said template set, wherein each of the plurality of matching degrees indicates a similarity between a portion of a corresponding one of said plurality of transmission images and one of said template set.