Study design: Retrospective.
Objective: To explore the shift in modalities when diagnosing the spine in the years 1979-2003. To see how this shift, together with a radiation protective policy, have influenced on the ionizing radiation doses.
Summary of background data: The shift from CT/myelography to MR when diagnosing the spine is well known. To what extent this has changed the radiation doses has to our knowledge not yet been published.
Methods: Activity reports from a department of radiology have been reviewed. Relevant radiation doses estimates have been obtained from the Norwegian Radiation Protection Authority.
Results: MRI was introduced in 1992 and has been used increasingly since then. Conventional X-ray to the spine has been practically unchanged. Myelography and CT decreased markedly after the introduction of MRI. The total number of examinations of the spine has increased, but the radiation doses given have decreased since 1993.
Conclusions: The introduction of MRI together with a radiation protective policy have reduced the ionizing radiation doses given to this population, in spite of an increase in the total number of examinations of the spine.