Radiation dose reconstruction
The volume Computed Tomography Dose Index (CTDICT head scans from the original study were retrieved from the PACS at the Karolinska University Hospital in Huddinge, Stockholm. From these CT images, the effective diameters of the participants’ heads were measured and compared to the diameter of the CTDI head phantom. Patients who underwent multiple examinations, such as two separate examinations of the head, two separate scans of head and face, or two overlapping series, were summed up into one within 24 hours total dose. For participants with CT scans overlapping the temporal lobe, the CTDIThe CT images contained metadata in accordance with the version of the Digital Imaging and Communications in Medicine (DICOM) standard, when the examinations were made. For this reason, all the information needed to reconstruct the CTDIFor the examinations with erroneous or lacking metadata (e.g. pitch, collimation, kV or mAs used), the CTDI