This study investigates the effects of an investigational antibody treatment for children with a type of cancer called neuroblastoma that has spread to the brain or the lining of the brain and spinal cord. Neuroblastoma is a cancer that starts in young nerve cells and can spread to other parts of the body. The study aims to understand how well the treatment works and how safe it is for these patients.

Participants in this study will receive a treatment called intracerebroventricular 131I-burtomab. This involves delivering the treatment directly into the fluid-filled spaces of the brain, which is known as the ventricular system. The study will monitor the effects of this treatment and compare them with previous research to determine its effectiveness.

• Who can participate: Children diagnosed with neuroblastoma that has returned in the central nervous system or the meninges can participate. They must not have a primary tumor in the central nervous system or any severe organ toxicity.
• Study details: Participants will receive the investigational treatment directly into the brain's ventricular system. This study does not involve a placebo, which is an inactive substance that looks like the investigational medicine but does not contain any medicine.