RecruitingPhase 4Drug trialOndansetron Orodispersible Film for Vomiting Prevention in Pediatric RadiotherapyThe goal of this study is to evaluate the antiemetic efficacy and drug safety of ondansetron orodispersible film in pediatric patients with malignant tumors who received moderate emetic risk radiation induced vomiting, and to formulate reasonable and effective clinical medication regimen for preventing vomiting caused by moderate emetic risk radiation in children with malignant tumor.