A flexible, non-absorbent sweatband includes a seal band sized to wrap around a wearer’s head and a clip into which the free ends of the seal band are secured at the back of the wearer’s head. The method is useful for treating patients with colorectal cancer and gastric carcinomas. The size andor color of the graphical elements are controlled in real time based on distance of the target location from a current image plane. A wiring line is formed on the insulating film in such a manner as to be connected to the external connection electrode via the connection opening.