REDUCING LENS IRRADIATION IN ROUTINE NON-CONTRAST CT BRAIN SCANS: A QUALITY IMPROVEMENT PROJECT

Published 2023 - 27th ESCRS Winter Meeting

Reference: P039 | Type: Presented Poster & Poster Submission | DOI: 10.82333/gvp3-q724

Authors: Matthew O'Riordan* ¹ , Zaid Tabba ² , Yusuf Fauzi ² , Nuala Lynch ² , David Reidy ² , Miriam Nash ² , Philip Hodnett ² , Michael O'Reilly ²

¹Ophthalmology,University Hospital Limerick,Limerick,Ireland, ²Radiology,University Hospital Limerick,Limerick,Ireland

Purpose

To reduce the proportion of routine non-contrast CT brain scans that include the lens of the eye. The lens is more sensitive to ionising radiation than previously assumed. Radiation-induced cataract formation is potentially stochastic without a threshold dose. European guidelines call for a 10–12° gantry tilt above the orbitomeatal line to reduce exposure.

Setting

Department of Radiology, University Hospital Limerick, Ireland.

Methods

Fifty routine non-contrast CT brain scans performed in University Hospital Limerick, Ireland were retrospectively audited to identify the proportion that include the lens of the eye in the imaging field. Patients between 16 and 80 years of age were included and trauma or ophthalmic/orbital indications were excluded. A 2 week radiographer refresher intervention period followed, emphasising incorporation of gantry tilt and encouraging patients to adopt a chin-tuck position. A repeat audit of 50 scans was then performed.

Results

The proportion of patients undergoing a routine non-contrast CT brain scan with no lenses irradiated improved from 10% (5/50) to 48% (24/50) upon re-auditing. The proportion of patients with both lenses irradiated decreased from 86% (43/50) to 44% (22/50).

Conclusion

We reduced the proportion of routine non-contrast CT brain scans that irradiate the lens of the eye, although we did not achieve our target of 80% lens exclusion. Gantry tilting is preferable but not possible/difficult with sliding-gantry CT systems. A chin tuck position can mimic gantry tilt, however can be limited due to patient specific factors. Either method, rigorously applied, should reduce radiation exposure to the lens and limit the risk of radiation-induced cataract formation.