Gold Nanoparticle Imaging and Radiotherapy of Brain Tumors in Mice

TLDR

The study aimed to evaluate intravenously injected 11‑nm gold nanoparticles for enhancing x‑ray imaging and radiotherapy of lethal intracerebral malignant gliomas. Gold nanoparticles (4 g Au/kg) were injected IV, imaged by micro‑CT, and after 15 h the brains received 30 Gy 100 kVp x‑rays, achieving a 19:1 tumor‑to‑normal brain gold ratio and a ~300 % local dose increase. Gold‑nanoparticle‑enhanced radiotherapy produced 50 % long‑term (>1 yr) tumor‑free survival versus none with radiation alone, demonstrating high‑resolution tumor imaging and suggesting clinical promise for brain and other cancers.

Abstract

To test intravenously injected gold nanoparticles for x-ray imaging and radiotherapy enhancement of large, imminently lethal, intracerebral malignant gliomas.Gold nanoparticles approximately 11 nm in size were injected intravenously and brains imaged using microcomputed tomography. A total of 15 h after an intravenous dose of 4 g Au/kg was administered, brains were irradiated with 30 Gy 100 kVp x-rays.Gold uptake gave a 19:1 tumor to normal brain ratio with 1.5% w/w gold in tumor, calculated to increase local radiation dose by approximately 300%. Mice receiving gold and radiation (30 Gy) demonstrated 50% long term (>1 year) tumor-free survival, whereas all mice receiving radiation only died.Intravenously injected gold nanoparticles cross the blood-tumor barrier, but are largely blocked by the normal blood-brain barrier, enabling high-resolution computed tomography tumor imaging. Gold radiation enhancement significantly improved long-term survival compared with radiotherapy alone. This approach holds promise to improve therapy of human brain tumors and other cancers.