X ray (XRT)/external beam irradiation including protons: >= 14 days after local XRT; >= 150 days after TBI, craniospinal XRT or if radiation to >= 50% of the pelvis; >= 42 days if other substantial bone marrow (BM) radiation At least 14 days after local palliative radiation therapy (XRT) (small port); at least 150 days must have elapsed if prior traumatic brain injury (TBI), craniospinal XRT or if >= 50% radiation of pelvis; at least 42 days must have elapsed if other substantial bone marrow radiation, including therapeutic doses of Iobenguane (MIBG) >= 2 weeks must have elapsed since local palliative radiation therapy (XRT) (small port); >= 6 weeks must have elapsed since treatment with therapeutic doses of M-Iodobenzylguanidine (MIBG); >= 3 months must have elapsed if prior craniospinal XRT was received, if >= 50% of the pelvis was irradiated, or if total-body irradiation (TBI) was received; >= 6 weeks must have elapsed if other substantial bone marrow irradiation was given\r\n* Subjects should not have any clinically relevant ongoing complications from prior radiation therapy (i.e., radiation esophagitis or other inflammation of the viscera) >= 2 weeks must have elapsed for local palliative radiation therapy (XRT) (small port) and enrollment on study; at least 24 weeks must have elapsed since prior total body irradiation (TBI), radiation to >= 50% of pelvis, or craniospinal radiation; >= 6 weeks must have elapsed if the patient has received other substantial bone marrow radiation Prior to registration, patients must be ? 14 days for local palliative radiation therapy (XRT) (small port); ? 90 days must have elapsed if prior total body irradiation (TBI), craniospinal XRT or if ? 50% radiation of pelvis; ? 45 days must have elapsed if other substantial bone marrow radiation Radiation therapy (XRT): at least 14 days after local palliative XRT (small port); 6 weeks must have elapsed since treatment with therapeutic doses of 131-meta-iodobenzylguanidine sulfate (I^131-MIBG); at least 150 days must have elapsed if prior traumatic brain injury (TBI), craniospinal XRT, or if >= 50% radiation of pelvis; at least 42 days must have elapsed if other substantial brain metastases (BM) radiation Patients enrolled in the study will meet standard criteria for whole breast XRT or chest wall XRT for patients who have had mastectomies >= 6 months must have elapsed if the patient has received involved field XRT or gamma knife that includes all target lesions (i.e., there is no restriction if a new lesion arises outside the radiation field or a non-irradiated lesion progresses); >= 6 months must have elapsed if the patient has received craniospinal XRT; >= 6 weeks must have elapsed if patient has received radiation to areas outside optic glioma Radiotherapy: >=2 weeks must have elapsed since local palliative radiotherapy (XRT) (small port); >=3 months must have elapsed if prior Traumatic Brain Injury (TBI), craniospinal XRT or if >=50% radiation of pelvis; >=6 weeks must have elapsed if other substantial bone marrow irradiation was given. Patients must have had their last fraction of:\r\n* Craniospinal irradiation >= 3 months prior to enrollment\r\n* Other substantial bone marrow irradiation >= 6 weeks prior to enrollment\r\n* Local palliative radiation therapy (XRT) (small port) >= 2 weeks INCLUSION CRITERIA FOR STRATUM C: Patients must have had their last fraction of:\r\n* Craniospinal irradiation >= 3 months prior to enrollment\r\n* Other substantial bone marrow irradiation >= 6 weeks prior to enrollment\r\n* Local palliative radiation therapy (XRT) (small port) >= 2 weeks At least 2 weeks must have elapsed since local radiation therapy (XRT) (small port); ? 3 months must have elapsed if prior cranial or craniospinal XRT was received, if ? 50% of the pelvis was irradiated, or if total body irradiation (TBI) was received; ? 6 weeks must have elapsed if other substantial bone marrow irradiation was given Local palliative radiation therapy (XRT) (small port) ?2 weeks before first dose of study drug Prior total body irradiation, total craniospinal XRT, or ?50% radiation of pelvis within 6 months of receiving first dose of study drug Must not have received radiotherapy (XRT) within 14 days prior to study drug administration (small field) or 42 days for craniospinal XRT, or if ?50% radiation of pelvis. Radiation therapy (XRT) >= 2 weeks for local palliative XRT; >= 6 months must have elapsed after XRT involving > 50% of the craniospinal axis or > 50% of the pelvis Has recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy\r\n* Myelosuppressive chemotherapy: At least 3 weeks since completion (6 weeks for nitrosourea)\r\n* Biologic (anti-neoplastic agent): At least 7 days since completion of therapy with a biologic agent\r\n* Radiation (XRT): ? 1 week must have elapsed from prior palliative XRT to non-target lesions Prior Therapy\r\n* Patients must have fully recovered from the acute toxic effects of all prior anti-cancer chemotherapy\r\n** Cytotoxic chemotherapy (including investigational agents) or biologic agents (eg. cytokines or antibodies): At least 3 weeks after the last dose\r\n** Nitrosoureas/mitomycin C: At least 6 weeks from the last dose\r\n** Radiotherapy (XRT): At least 14 days after local palliative XRT (small port); at least 150 days must have elapsed if prior traumatic brain injury (TBI), craniospinal XRT or if >= 50% radiation of pelvis; at least 42 days must have elapsed if other substantial bone marrow (BM) radiation; e.g. stem cell Infusion without TBI: no evidence of active graft versus (vs.) host disease and at least 56 days must have elapsed after transplant or stem cell infusion Prior definitive radiation therapy (XRT) is allowed if it has been 2 weeks since the end of definitive XRT; for palliative XRT, protocol-specified treatment can begin at minimum 48 hours after completion of radiation; lesions within the XRT field can only be used as target lesions if definite progression has been demonstrated since the completion of radiation At least 2 weeks must have elapsed since local palliative radiation therapy (XRT) (small port); at least 6 weeks must have elapsed since treatment with therapeutic doses of metaiodobenzylguanidine (MIBG); at least 3 months must have elapsed if prior craniospinal XRT was received, if more than 50% of the pelvis was irradiated, or if total body irradiation (TBI) was received; at least 6 weeks must have elapsed if other substantial bone marrow irradiation was given The subject must have recovered from the acute toxic effects of all prior therapy with the exception of alopecia. The following time must have elapsed from the last dose of the following medications to study enrollment:\r\n* Myelosuppressive chemotherapy: 14 days\r\n* Hematopoietic growth factors: 7 days (14 days for Neulasta)\r\n* Biologic agent: 7 days\r\n* Monoclonal antibody: 3 half-lives \r\n* Immunotherapy (ie tumor vaccines): 42 days\r\n* Palliative small port radiation therapy (XRT): 14 days\r\n* Substantial bone marrow XRT: 6 weeks\r\n* Stem cell transplant or infusion without total body irradiation (TBI): 12 weeks\r\n* Total body irradiation (TBI): 24 weeks Radiation therapy - At least 14 days must have elapsed for local XRT. At least 90 days must have elapsed if prior radiation to ?50% of the pelvis, the spine, or other substantial bone marrow radiation including TBI. >= 2 weeks must have elapsed for local radiation therapy (XRT) (small port); >= 6 months must have elapsed if prior radiation to >= 50% of the pelvis or if other substantial bone marrow irradiation, including total body irradiation Radiotherapy (XRT): at least 4 weeks for focal XRT or 8 weeks for craniospinal XRT must have elapsed prior to study entry At least 14 days after local palliative XRT (small port); At least 150 days must have elapsed if prior TBI, craniospinal XRT or if ? 50% radiation of pelvis; At least 42 days must have elapsed if other substantial bone marrow radiation. Patients must have had prior radiation therapy for treatment of their ependymoma; external beam radiation therapy (XRT) must be >= 3 months prior to registration for craniospinal irradiation (>= 18 Gray [Gy]); >= 4 weeks for local radiation to primary tumor; and >= 2 weeks prior to registration for focal irradiation to symptomatic metastatic sites No radiation therapy >= 14 days for local palliative radiation therapy (XRT) (small port): >= 6 months must have elapsed if prior craniospinal XRT or if >= 50% radiation of pelvis; >= 42 days must have elapsed if other substantial bone marrow radiation Radiation therapy (XRT)/External Beam Irradiation including Protons: ?14 days after local XRT, ?150 days after TBI, craniospinal XRT or if radiation to ?50% of the pelvis, ?42 days if other substantial BM radiation Patients who require local palliative measures such as XRT or surgery Radiation therapy (RT): >= 2 weeks for local palliative RT (small port); >= 6 months must have elapsed if prior craniospinal RT or if >= 50% radiation of pelvis; >= 6 weeks must have elapsed if other substantial bone marrow (BM) radiation; Note: patients must have received =< than 13.6 Gray (Gy) prior radiation to the mediastinum External beam radiation therapy (XRT): at least 14 days after local palliative XRT (small port); at least 150 days must have elapsed if prior total body irradiation (TBI), craniospinal XRT or if >= 50% radiation of pelvis; at least 42 days must have elapsed if other substantial bone marrow (BM) radiation Patients with prior TBI, craniospinal XRT and/or those with >= 50% radiation of the pelvis are not eligible Patients may have received palliative external beam radiation therapy (XRT) for local disease control with no curative intent; XRT must be completed at least 7 days prior to registration >= 2 weeks (wks) for local palliative radiation therapy (XRT) (small port); >= 6 weeks must have elapsed since treatment with therapeutic doses of MIBG; >= 6 months must have elapsed if prior total body irradiation (TBI), craniospinal XRT or >= 50% radiation of pelvis; >= 6 wks must have elapsed if other substantial bone marrow (BM) radiation 2 weeks for local palliative radiation therapy (XRT). Radiotherapy (XRT)/External Beam Irradiation including Protons: ?14 days after local XRT; ?150 days after total body irradiation, craniospinal XRT or if radiation to ?50% of the pelvis; ?42 days if other substantial bone marrow radiation. The following amounts of time must have elapsed prior to entry on study:\r\n* 2 weeks from local radiation therapy (XRT)\r\n* 8 weeks from prior craniospinal or if > 50% of the pelvis has been irradiated\r\n* 6 weeks must have elapsed if other bone marrow radiation has occurred For all patients, >= 4 weeks must have elapsed for local external beam radiation therapy (XRT); >= 6 months must have elapsed if prior radiation to >= 50% of the pelvis or if substantial bone marrow irradiation; patients with a history of prior radiation with field including the heart (i.e. mantle) will be excluded Craniospinal radiation therapy (XRT) is prohibited during protocol therapy; no washout period is necessary for radiation given to non-CNS chloromas; >= 90 days must have elapsed if prior traumatic brain injury (TBI) or craniospinal XRT Patients must have had their last fraction of:\r\n* Craniospinal irradiation (> 24 Gray [Gy]) or total body irradiation > 3 months prior to registration\r\n* Local palliative external beam radiation therapy (XRT) (small port) >= 2 weeks \r\n* Other substantial bone marrow (BM) radiation >= 6 weeks must have elapsed Radiotherapy: 3 weeks must have elapsed since radiation therapy (XRT) >= 2 weeks must have elapsed for local palliative radiation therapy (XRT) (small port) and enrollment on study; at least 24 weeks must have elapsed since prior total body irradiation (TBI), radiation to >= 50% of pelvis, or craniospinal radiation; >= 6 weeks must have elapsed if the patient has received other substantial bone marrow (BM radiation); >= 6 weeks for prior metaiodobenzylguanidine (MIBG) therapy; for patients with only one site of measurable or evaluable disease, radiation must not have been given to that site unless that site has demonstrated clear progression after radiation or at least 2 months have elapsed since radiation and their remains evidence of viable tumor on biopsy, fludeoxyglucose (FDG) pet scan or MIBG scan Has recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy\r\n* Myelosuppressive chemotherapy: At least 3 weeks since completion (6 weeks for nitrosourea)\r\n* Biologic (anti-neoplastic agent): At least 14 days since completion of therapy with a biologic agent\r\n* Radiation (XRT): >= 1 week must have elapsed from prior palliative XRT to non-target lesions Prior radiotherapy (RT): At least four weeks since completion of whole-brain irradiation, at least two weeks since completion of prophylactic cranial irradiation, and to any other site. Patients must have had their last fraction of: \r\n* Craniospinal irradiation (> 24 GRAY [Gy]) or total body irradiation > 12 weeks prior to enrollment\r\n* Focal irradiation > 2 weeks prior to enrollment\r\n* >= 3 months since autologous bone marrow/stem cell transplant prior to enrollment Patient has received radiation therapy prior to study registration; patients must have had their last fraction of local irradiation to the primary tumor >= 3 months prior to registration, their last fraction of craniospinal irradiation (>= 24 Gy) or total body irradiation >= 3 months prior to registration or >= 6 weeks (wks) for the therapeutic doses of MIBG; patient has not received focal irradiation for symptomatic metastatic sites within 14 days prior to registration Prior total body or hemi-body irradiation Subject who has received prior pelvic irradiation or is scheduled for pelvic nodal irradiation Radiation therapy within 2 weeks prior to randomization, including stereotactic or partial brain irradiation. Whole brain irradiation within 4 weeks prior to randomization Radiation: patients must have:\r\n* Had their last fraction of local irradiation to primary tumor >= 12 weeks prior to registration; investigators are reminded to review potentially eligible cases to avoid confusion with pseudo-progression\r\n* Had their last fraction of craniospinal irradiation or total body irradiation >= 12 weeks prior to registration Participants may have received prior cranial irradiation Disease has progressed through at least one systemic therapy or through local irradiation within the preceding 6 months. Radiotherapy: patients must have had their last fraction of: \r\n* Focal irradiation > 2 weeks prior to enrollment Prior prophylactic cranial irradiation (PCI) is allowed Lesion that is technically feasible to irradiation and accessible for direct intratumoral injection Radiation: patients must have:\r\n* Had their last fraction of local irradiation to primary tumor >= 12 months prior to registration; investigators are reminded to review potentially eligible cases to avoid confusion with pseudo-progression\r\n* Had their last fraction of craniospinal irradiation (> 24 Gy) > 3 months prior to registration Prior irradiation to > 30% of BM reserves (including total body irradiation), regardless of the washout period; Prior radiation: Cranial irradiation, total body irradiation (TBI), or ? 50% radiation of pelvis ? 3 months prior to screening. Focal irradiation: ? 3 weeks prior to screening if radiation field involved a nontarget lesion; ? 6 weeks prior to screening if radiation field involved a target lesion. Note: True disease progression following prior irradiation therapy must be confirmed by Investigator prior to screening. • Bone marrow transplant: < 6 months since allogeneic bone marrow transplant prior to screening. < 3 months since autologous bone marrow/stem cell transplant prior to screening. < 3 months since stem cell transplant (SCT) or Rescue without TBI with no evidence of GVHD prior to screening. • Radioisotopes: fluorothymidine (18FLT) ? 72 hours prior to first dose of study drug Plans to administer irradiation to the breast only Prior thoracic irradiation Prior whole brain irradiation Previous pelvic irradiation therapy history of mediastinal or pulmonary irradiation History of prior irradiation to the area to be treated Previous irradiation that precludes the safe administration of an additional dose of 200 cGy of total body irradiation (TBI) Previous total body irradiation, or irradiation of >25% of the patient's bone marrow. Prior whole brain irradiation Prior mediastinal irradiation (for any reason) Prior whole brain irradiation Prior whole brain irradiation Prior total body irradiation (TBI) Prior whole/partial brain irradiation or stereotactic radiosurgery Prior total body irradiation, prior total abdominal or whole liver radiation Patients must not have received previous irradiation to the brain Progressive intracranial ependymoma after prior focal irradiation Prior craniospinal irradiation Prior intracavitary irradiation or Gliadel wafers Prior whole brain irradiation Prior therapeutic radiation exposure to tissues for which protocol irradiation is anticipated is an exclusion criterion Patients must have had their last fraction of: \r\n* Craniospinal irradiation (> 24 Gy) > 3 months prior to enrollment\r\n* Focal irradiation > 42 days prior to enrollment\r\n* Local palliative irradiation (small port) > 14 days Prior whole brain irradiation Prior cranial irradiation Patients who have received cranial or spinal irradiation less than 3 weeks prior to the start of this protocol Stem cell infusions (with or without total body irradiation [TBI]): ?84 days ?12 weeks for total skin electron beam irradiation, Patients are excluded if they have received total body irradiation (TBI) Prior whole brain irradiation Patients with tumors that are not curable by salvage approaches including resection and/or re-irradiation. Prior whole brain irradiation. Patients must have:\r\n* Had their last fraction of local irradiation to primary tumor >= 12 weeks prior to registration\r\n* Had their last fraction of craniospinal irradiation or total body irradiation >= 12 weeks prior to registration Prior neck radiotherapy that would preclude re-irradiation Prior irradiation is allowed if > 28 days prior to registration have elapsed since\n the date of last treatment. Patients with a history of pelvic irradiation for any reason Prior cranial irradiation Patients who have received prior pelvic irradiation are not eligible At least 12 weeks for craniospinal, ?50% radiation of pelvis, or total body irradiation prior to first dose of study drug No prior abdominopelvic radiotherapy is allowed except for total body irradiation administered >= 10 years prior; no prior systemic therapy for anal cancer Total body irradiation (TBI) or craniospinal radiation therapy <6months Prior irradiation to lung fields History of prior chemotherapy or pelvic irradiation No history of previous pelvic irradiation History of prior pelvic irradiation Any prior melanoma treatment other than surgery or regional irradiation The participant has undergone chest irradiation within 2 weeks prior to receiving study treatment. Patients must have had their last fraction of:\r\n* Craniospinal irradiation, total body irradiation (TBI), or >= 50% radiation of pelvis > 3 months prior to enrollment\r\n* Focal irradiation > 6 weeks prior to enrollment\r\n* Local palliative radiation therapy (XRT) (small port) >= 4 weeks Surgery or irradiation ? 4 weeks prior to randomization Recommended to undergo pelvic irradiation with concurrent chemotherapy Prior abdomino-pelvic irradiation Prior pelvic irradiation. No history of previous chemotherapy or pelvic irradiation History of prior chemotherapy or pelvic irradiation Patients must not have received any prior pelvic irradiation Patients will be allowed to participate following single prior CNS treatment with stereotactic radiotherapy whole brain irradiation and stable without steroid requirement for ?2 months or following ?2 prior CNS treatments with stereotactic radiotherapy whole brain irradiation and stable without steroid requirement for ?4 months. Patients must be at least 6 weeks out from pelvic irradiation, and must not have more than 10% of bone marrow irradiated. Patients who have received cranial or spinal irradiation less than 3 weeks prior to the start of this protocol RECURRENT/ PROGRESSIVE DIPG (STRATUM 1): Patients must have had their last fraction of: \r\n* Craniospinal irradiation or radiation to >= 50% of pelvis > 3 months prior to enrollment\r\n* Focal irradiation to the primary site > 42 days prior to enrollment\r\n* Local palliative irradiation other than previously irradiated primary site (small port) >= 14 days NON-PROGRESSED DIPG (STRATUM 2): Patients must have had their last fraction of focal irradiation to the primary site > 14 days prior to enrollment; patients must not have received local palliative irradiation or craniospinal irradiation Prior total body irradiation (TBI) making TMI not feasible Patients who have pelvic irradiation with doses ? 45 Grays (Gy). At least 60 days from prior total body irradiation (TBI) Patient had a resection and/or completed a course of cranial irradiation; and Patients with prior whole brain irradiation Prior history of pelvic irradiation Irradiation to more than 25% of bone marrow-bearing areas History of extensive prior pelvic irradiation. Has undergone chest irradiation within 12 weeks prior to randomization (except palliative irradiation of bone lesions) External radiation therapy (XRT): Must not have received XRT within 3 months prior to study entry for craniospinal irradiation (> 24 Gy) or total body irradiation or if >= 50% radiation of pelvis; >= 8 weeks for local irradiation to primary tumor; >= 2 weeks for focal irradiation for symptomatic metastatic sites Prior whole brain irradiation Evidence or suspected recurrent or metastatic disease; prior brain irradiation is not allowed Patient is felt not to be a candidate for total-body irradiation (TBI) by the Bone Marrow Transplant (BMT) service Skin disease in target irradiation area Disease-based radiation therapy (not total body irradiation) Patients’ proposed post-operative treatment plan must include standard focal brain irradiation and temozolomide Patients may have started consolidative chest irradiation by the time of study entry Patients receiving prior external beam irradiation to the head or neck, including any form of stereotactic irradiation Subjects who have previously received or have planned Total Body Irradiation (TBI) Patient has received or is scheduled to receive total body irradiation, total nodal irradiation, upper abdomen radiotherapy, half or upper body irradiation, radiotherapy of the cranium, craniospinal regions, head and neck, lower thorax region or the pelvis within 1 week prior to study entry (Day 1) or within 120 h after start of chemotherapy administration on Day 1. Prior pelvic irradiation Prior re-irradiation or stereotactic radiosurgery for recurrent disease at the same tumor location intended for HFRT in this study History of re-irradiation to a field which includes the carotid arteries