The study involves children aged 12‑17 years who have Acute lymphoblastic leukemia and lymphoma, cancers that affect the blood or lymph system. These patients receive intrathecal chemotherapy, which means the chemotherapy drugs are given directly into the fluid that surrounds the spinal cord. The usual medicines used for this purpose are methotrexate and, when needed, cytarabine. In addition, a small amount of the contrast agent gadobutrol will be injected into the same fluid to measure how quickly the brain’s fluid is cleared, a process referred to as brain fluid clearance. The purpose of the study is to investigate individual brain fluid clearance in children receiving intrathecal chemotherapy.
After the gadobutrol injection, blood samples will be taken at several time points to see how the substance moves through the body, and the children will continue their regular chemotherapy schedule. Participants will be observed for any immediate reactions for about half an hour after the injection and will be asked about common symptoms such as headache, nausea, or dizziness during the first week. Additional follow‑up visits will include simple questionnaires that measure mental fatigue and more detailed tests of thinking and memory at three months, and again at two years, to check for any changes in brain function. All procedures are designed to be as safe and comfortable as possible while gathering information that could help tailor future treatments.
Norway 
