Relative calibration for dosimetric devices

A system for calibrating the dose response of a device image acquisition (110), comprising: means for generating a first self-calibration curve (114) relates dosages of a first dose map (106) to intensities in a first acquired image (112), the first dose map (106) generated according to a first treatment plan (104); means for generating a second self-calibration curve (114) relates dosages of a second dose map (106) to intensities in a second acquired image (112); means for generating an initial calibration that relates dosages provided according to the first treatment plan (104) to intensities in the first acquired image (112); and means for performing calculations that include: (1) determining at least one difference or fit between the first self-calibration curve (114) and the second self-calibration curve (114); (2) modifying the second acquired image (112) based on the at least one difference or fit; and (3) producing a relative calibration based on an application from the initial to the second acquired image (112) calibration.