Determinants of Radiation Dose in Selective Ophthalmic Artery Chemosurgery for Retinoblastoma

BACKGROUND AND PURPOSE: Retinoblastoma is the most common pediatric ocular neoplasm. Multimodality treatment approaches are commonplace, and selective ophthalmic artery chemosurgery has emerged as a safe and effective treatment in selected patients. Minimizing radiation dose in this highly radiosensitive patient cohort is critical. We explore which procedural factors affect the radiation dose in a single-center cohort of children managed in the UK National Retinoblastoma Service.

MATERIALS AND METHODS: A retrospective review was performed of 177 selective ophthalmic artery chemosurgery procedures in 48 patients with retinoblastoma (2013–2017). Medical records, angiographic imaging, and radiation dosimetry data (including total fluoroscopic screening time, skin dose, and dose-area product) were reviewed.

RESULTS: The mean fluoroscopic time was 13.5 ± 13 minutes, the mean dose-area product was 11.7 ± 9.7 Gy.cm², and the mean total skin dose was 260.9 ± 211.6 mGy. One hundred sixty-three of 177 procedures (92.1%) were technically successful. In 14 (7.9%), the initial attempt was unsuccessful (successful in 13/14 re-attempts). Screening time and radiation dose were associated with drug-delivery microcatheter location and patient age; screening time was associated with treatment cycle.

CONCLUSIONS: In selective ophthalmic artery chemosurgery, a microcatheter tip position in the proximal or ostial ophthalmic artery and patient age 2 years or younger were associated with reduced fluoroscopic screening time and radiation dose; treatment beyond the first cycle was associated with reduced fluoroscopic screening time.