The Radiation Exposure Associated with Cervical and Lumbar Spine Radiographs

Study Design: Cross-sectional study.

Objective: To calculate the effective radiation doses of routine anteroposterior (AP) and lateral radiographs of the cervical and lumbar spines.

Summary Of Background Data: Although plain radiographs are generally used as the initial imaging modality for the evaluation of patients with spinal complaints, the radiation that patients receive during these studies has not been well quantified. The effective radiation dose represents a functional measure of exposure that takes into account the amount of radiation delivered and the radiosensitivity of the exposed organs. Consequently, the effective dose is important to consider from a radiation safety perspective.

Methods: The imaging practices of our radiology department were reviewed and the effective radiation doses for AP and lateral radiographs of the cervical and lumbar spines were calculated using the following variables: emitted radiation dose, source-to-object distance [SOD], film area, and patient tissue dimensions. Values were obtained from both direct measurements and an examination of the established protocols employed at our institution.

Results: The effective doses for AP and lateral cervical radiographs were 0.12 and 0.02 mSv, respectively, whereas the corresponding values for AP and lateral lumbar films were much larger (2.20 and 1.50 mSv, respectively). For comparative purposes, a typical chest x-ray results in a radiation dose between 0.06 and 0.25 mSv.

Conclusions: In this investigation, cervical spine films gave rise to radiation doses that are similar to those of chest x-rays. However, lumbar spine radiographs generated effective radiation doses that were approximately an order of magnitude greater than these other studies. In both the cervical and lumbar regions, AP views resulted in significantly greater radiation exposure than corresponding lateral images. The effective radiation doses reported here may prove to be valuable for assessing the relative risks and benefits of spine radiographs to establish appropriate guidelines for their use.