For which lymphoma patients is radiotherapy indicated? Radiotherapy is the primary treatment for stage I and II Hodgkin’s lymphoma and for low-grade malignant stage I and II non-Hodgkin’s lymphoma. There are four types of radiotherapy: irradiation of the involved site, expanded site and secondary whole lymph nodes or whole body lymph nodes. In addition to the involved lymph nodes and tumor tissues, the expanded irradiation must also include the nearby lymph node areas that may be invaded. If the lesion is above the diaphragm, the cloak is used, and below the diaphragm, the inverted “Y” or combined hoe is used. Whole-body lymph node irradiation includes cloak, hoe and inverted “Y”. What are the limitations of radiotherapy for lymphoma? First, for Hodgkin’s lymphoma, because the pathway of spread is not through the lymphatic area, the large irregular irradiated fields of cloak, hoe and inverted “Y” are less effective and have a higher recurrence rate. Secondly, radiotherapy does not only target lymphoma cells, but also kills normal cells in the irradiated area, so it often causes great damage to the patient.