Acute Radiation SyndromeGastrointestinal NeoplasmsRadiation InjuriesRadiation Injuries, ExperimentalRadioactive Hazard ReleaseRadiodermatitisRadiation DosageDose-Response Relationship, RadiationTogoSemustineSyndromeWhole-Body IrradiationRadiation-Protective AgentsRadiation PneumonitisProctitisCarcinoid TumorRadiation ToleranceGastrointestinal Stromal TumorsNeuroendocrine TumorsStomach NeoplasmsLethal Dose 50Duodenal NeoplasmsPancreatic NeoplasmsRadiometryRadiotherapyAdenocarcinomaGamma RaysRadiation, IonizingColonic NeoplasmsRectal NeoplasmsCell Line, TumorFluorouracilCarcinoembryonic AntigenColorectal NeoplasmsEsophageal NeoplasmsNeoplasmsRadiationAntineoplastic Combined Chemotherapy ProtocolsLiver NeoplasmsRadiation ProtectionMice, Inbred C57BLRadiation MonitoringTumor Cells, CulturedTumor Markers, BiologicalTumor BurdenTumor Necrosis Factor-alphaDown SyndromeMetabolic Syndrome XRadiation OncologyTreatment OutcomeWilms TumorTime FactorsBrain NeoplasmsNeoplasms, ExperimentalTumor Suppressor Protein p53Neoplasms, Radiation-InducedCombined Modality TherapyGenes, Tumor Suppressor