Apparatus for improving image guidance in radiation therapy applications are described. In one aspect, a patient support with integrated radiopaque markers is described. In another aspect, a bite block with integrated sensors, radiopaque markers, or both, is described. The integrated sensors may include a radiation detector, a pH sensor, or both. Radiation detectors that may be used include a dosimeter. As an example, the dosimeter may include a film dosimeter, an ion chamber dosimeter, a diode dosimeter, or other suitable dosimeters and combinations thereof.