A method for increasing radiosensitivity of a tumor in a subject via administration of a VEGF-R2 inhibitor to a tumor in a subject. Depth map images from a depth camera may be processed to calculate a probability that each pixel of the depth map is associated with one or more segments or body parts of a body. When the sensed contamination is higher than that of the performance map the operator is warned of a malfunction. An image of a virtual space after laying out the list image, which is seen in accordance with the position and orientation of the viewpoint, generated.