24-Gy Low-Voltage X-Ray Irradiation With Ranibizumab Therapy for Neovascular AMD: 6-Month Safety and Functional Outcomes

BACKGROUND AND OBJECTIVE: To describe the 6-month safety and preliminary efficacy outcomes of the use of 24-Gy radiation with intravitreal ranibizumab for patients with neovascular age-related macular degeneration (AMD). PATIENTS AND METHODS: A single treatment of a non-invasive, externally delivered low-voltage x-ray irradiation at a dose of 24 Gy was administered in one session through three locations in the inferior pars plana in a consecutive series of patients with neovascular AMD (treatment naive and previously treated). Optical coherence tomography (OCT) and Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity examinations were performed at 1 week, 1 month, and monthly thereafter with quarterly fluorescein angiography. RESULTS: Nineteen patients completed 6 months of follow-up. There was no evidence of radiation retinopathy, optic neuropathy, or cataract. The mean baseline ETDRS score was 38.3 +/- 19.5 letters. At 6 months, the corresponding ETDRS score was 44.7 +/- 16.8 letters. At 6 months, the mean change in visual acuity was 6.4 +/- 9.8 ETDRS letters. Patients received an average of 0.4 additional ranibizumab injections following the initial two mandated injections. CONCLUSION: A single treatment of external 24-Gy low-voltage x-ray therapy in conjunction with ranibizumab demonstrated an overall improvement in visual acuity in patients with neovascular AMD at 6 months, with no radiation-related adverse effects.