Certain embodiments of the present invention provide methods and systems for determining a location of an object of interest for use in image calibration. Certain embodiments of a method include loading an image of at least a portion of a patient. The image includes an object of interest. The method further includes retrieving patient data related to the patient, and automatically generating a proposed height value of the object of interest in relation to a reference location. The proposed height value is generated by selecting a height value from a set of height values based on the patient data. In certain embodiments, the reference location is a positioning tabletop. In certain embodiments, the patient data includes patient height and/or patient weight, and the set of height values is indexed based on height and/or weight by gender.