A processing device for a radiation device is configured to carry out the steps of retrieving, from a data storage, volume data of a subject that was generated by imaging an internal structure of the subject, determining a position of an object in the subject based on the retrieved volume data of the subject, obtaining geometry information including a position of a radiation source and a position of a radiation detector, and obtaining a direction of the radiation detector, and determining a condition for imaging with the radiation source, so that the object can be captured through the imaging, based on the volume data, the position of the object, the position of the radiation source, the position of the radiation detector, and the direction of the radiation detector.
