Radiation Doses in Patient Eye Lenses during Interventional Neuroradiology Procedures.

Abstract

Eye lenses are among the most sensitive organs to x-ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients' eyes during interventional neuroradiology procedures at a university hospital. Small optically stimulated luminescence dosimeters were located over patients' eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane x-ray system. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. The left eye (located toward the lateral C-arm x-ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maximum of 2000 mGy in a single procedure. The patient who received this maximum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. Sixteen percent of the embolizations resulted in eye doses of >500 mGy. A relevant fraction of patients received eye doses exceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.