<prompt> Cranial irradiation is useful in treatment of?MedulloblastomaAstrocytomaGerminomaAll of the above  <response>: Ans. D. All of the above. Ref. Walter and Millers Textbook of Radiotherapy 7thCh. 33Craniospinal irradiation is used for patients who have, or are at risk for, disseminated disease throughout the CNS that is not sufficiently responsive to chemotherapy typically methotrexate. This includes: Embryonal CNS malignancies medulloblastoma, PNET, atypical teratoidrhabdoid tumour Intracranial germ cell tumour with evidence of distant CNS metastases. Epenedymoma with evidence of distant CNS metastases or CSF involvement- Craniospinal radiation is central to the management of medulloblastoma. Depending upon the age and the use of chemotherapy, cranio-spinal irradiation CSI of 25 to 35 Gy and boost radiation to the posterior fossa to a total dose of 50-55Gy over 6-7 weeks is the standard of care.- Post operative radiotherapy localised fields to a dose of 54 Gy30 is required in selected cases with residual cerebellar astrocytoma particularly in the brain stem. Chemotherapy is generally not indicated in these tumours.- In germinomas, Radiotherapy directed toward the craniospinal axis or tumor site alone at decreased dose levels is effective.Tumours with high propensity for neuraxis dissemination include : medulloblastoma, intracranial germ cell tumour, primary CNS lymphoma and undifferentiated round cell tumours such as ependymoblastoma and PNET. 