Facility reference level distribution variation over time

The curves below show the change in the median of the FRL distribution since the beginning of 2012 for different protocols. The graphs have been generated by examining the surveys submitted during a moving 12-month period, where the start and end points of the window have been shifted by daily intervals. The x-axis is the end date of the 12-month interval, the blue line is the median of the corresponding FRL distribution, the red line denotes the current DRL and the light blue region indicates the 25th – 75th percentile range.

Note that the cervical spine, KUB and soft-tissue neck data are not included because the protocols have only been introduced recently.


Variation head CTDI Variation head DLP

Soft-tissue neck

Variation soft tissue neck CTDI Variation soft tissue neck DLP

Cervical spine 

Variation cervical spine CTDI Variation cervical spine DLP


Variation chest CTDI Variation chest DLP


Variation chest abdomen pelvis CTDI Variation chest abdomen pelvis DLP


Variation abdomen pelvis CTDI Variation abdomen pelvis DLP

Kidney Ureter Bladder

Variation kidney ureter bladder CTDI Variation kidney ureter bladder DLP

Lumbar spine

Variation lumber spine CTDI Variation lumber spine DLP