With the advancement of medical technology body composition analysis BCA as a non-invasive and user-friendly assessment tool has played an increasingly significant role in the field of radiation therapy. BCA provides a new dimension for evaluating the nutritional status of radiation therapy patients by precisely quantifying key indicators such as muscle mass fat mass and body water content. These indicators not only reflect the metabolic status of patients but also predict treatment outcomes and potential risks of adverse reactions providing a scientific basis for the formulation of personalized radiation therapy plans. Currently the application of BCA in the management of radiation therapy patients has demonstrated remarkable potential optimizing treatment regimens improving therapeutic efficacy and reducing toxic side effects thereby enhancing patients' quality of life. This review summarizes recent research progress on the application of BCA in radiation therapy patients explores the effects of radiation therapy on patients' body composition and the relationship between these changes and treatment outcomes and patient prognosis. Meanwhile it evaluates currently used BCA methods including their advantages and limitations. We aim to promote the routine clinical application of BCA in radiation therapy providing patients with more personalized and effective treatment plans through precise body composition analysis. Furthermore this article looks into the future development directions of BCA technology and how technological innovations can meet clinical needs further enhancing the scientificity and effectiveness of radiation therapy