It should be noted, however, that exam (scanning) times are highly variable. There exist many factors that may influence scan time, including the type of scanner and software used, the organ under investigation, the type of examination (. T1 vs. T2-weighted imaging), etc. There seems to be no organized way to account for this variability, which often results in delays and/or idle time, as scans may take longer or shorter time than the assigned appointments. The average number of scans per day is 8 (with rather large SD of ) for both scanners.