A method comprises: acquiring imaging data using a tomographic radiological imaging apparatus (10) updating a calibration (42, 52) based on current information about the imaging apparatus calibrating the imaging data using the up-to-date calibration and reconstructing the calibrated imaging data to generate an image. The updating may be based on a current state of an idle or parked imaging modality that is not used in acquiring the imaging data, or on a measurement acquired together with the imaging data, or on the imaging data itself. For cone-beam computed tomography (CBCT) imaging data, the updating may comprise determining an intensity scale based upon intensity of at least one air pixel measured during the acquiring of the CBCT imaging data and updating an air scan template (60) by the intensity scale.
