Imaging the central nervous system effects of radiation and chemotherapy of pediatric tumors.

New developments in radiotherapy and chemotherapy have resulted in significant improvements in survival from childhood tumors. Stereotactic radiosurgery and other conformed field radiotherapy treatments allow precise localization of tumors. Through small beam sizes, these new radiation techniques deliver steep dose gradients at the field edges permitting the prescribed dose to be given to the tumor while avoiding vital structures only millimeters away. Newer chemotherapy regimens allow radiotherapy to be postponed until the child's brain can better tolerate radiation. The MR imaging and CT scans appearance of treated childhood brain tumors and the new developments in radiation and chemotherapy are discussed.