Impact of Patient Head Posture on Lens Radiation Exposure During Cerebral Angiography

Cerebral angiography remains crucial for detailed characterization and preoperative assessments for intracranial aneurysm. Despite its diagnostic importance, cerebral angiography poses challenges due to its invasiveness, the risk of neurologic complications, and radiation exposure. To investigate the impact of head posture on lens radiation exposure during cerebral angiography, this study focused on the correlation between radiation doses to the eye lens, head flexion angles, and head size.

A retrospective analysis was performed on 20 patients who underwent cerebral angiography for unruptured intracranial aneurysms between October and November 2022. Radiation doses to the lens, which were measured in a prior prospective study by using photoluminescent glass dosimeters, were analyzed alongside head flexion angles, anterior-posterior (AP) head diameters, and kerma-area product (KAP) to evaluate their correlation with lens radiation exposure. The lateral radiation source is located on the left side of the patients.

The cohort consisted of 20 patients (60% women, mean age: 62.3 ± 9.9 years). The radiation dose to the left eye (the eye closer to the x-ray source) was 2.8 times higher than that to the right eye (9.18 ± 3.31 mGy versus 3.3 ± 0.60 mGy, P < .001). A strong positive correlation was observed between the left eye lens dose and head flexion angle (R = 0.815, P < .001). While the AP head diameter correlated significantly with the flexion angle, it showed no significant correlation with lens dose. The KAP was inversely correlated with both the left lens dose (R = -0.597, P = .005) and the flexion angle (R = -0.689, P < .001).

Our findings underscore the meaningful impact of head posture on lens radiation exposure during cerebral angiography. Adjusting head positioning may provide a practical approach to reduce radiation exposure to the lens. Furthermore, it is worth noting that the left lens received more radiation than the right, likely due to the x-ray source being on the left side of the patient.