Lens Exclusion in Computed Tomography Scans of the Brain—The Local Practice

KF Lai, YK Cheung, CB Tan, E Tsui, SK Yu

Hong Kong J Radiol 2001;4:181-4

Objectives: To review protocols used in Hong Kong public hospitals for computed tomography brain scans, with a view to highlighting potential radiation damage to the lens with particular scanning planes.

Methods: Following a survey of radiological practice in 8 local hospitals, a retrospective study of routine computed tomography brain scanning, with special interest in avoidance of lens exposure, was completed in 2 major regional hospitals. Six hundred patient records were reviewed, along with the scanning protocols used.

Results: The orbitomeatal plane was the predominant reference plane utilised by the majority of public hospitals in this locality, including the 2 hospitals investigated in depth. More than 90% of patients in the study population were found to have either one or both lenses irradiated, despite differences in machines and staff.

Conclusion: A protocol for computed tomography brain scanning, specifying a baseline orientation which excludes the lens, should be established in hospitals to prevent routine lens irradiation.