A method is for determining a patient weight and/or a body mass index of a patient. The method includes acquiring image data containing depth information of the patient； generating a surface model of the patient based upon the image data acquired； determining density information or X-ray attenuation information of at least part of the patient； and determining at least one of the total patient weight and the body mass index of the patient using the surface model generated and the density information or X-ray attenuation information determined.
