The present disclosure provides a system and method for dose measurement in radiation therapy. The method may include obtaining a beam model and a detector model related to a radiation device, and a reference image and a treatment plan related to the subject, and determining a synthetic image based on the beam model, the detector model, and the reference image. The method may also include obtaining a treatment image by performing at least a portion of the treatment plan including delivering at least a radiation beam toward the subject using the radiation device, and determining one or more scaling factors. The method may further include determining a synthetic estimate of the treatment image based on the synthetic image and the one or more scaling factors. The method may further include estimating radiation dose deposition based on the treatment image and the synthetic estimate of the treatment image.