This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Craniospinal irradiation is employed in the treatment of: 
Select and explain. 
A. Oligodendroglioma, B. Pilocytic astrocytoma, C. Mixed oligoastrocytoma, D. Medulloblastoma
D: Medulloblastoma
Answer: D: Medulloblastoma 
Explanation: Medulloblastoma