This chapter outlines the increasingly important role of advanced imaging methods in the radiotherapy for Hodgkin lymphoma (HL). CT has become the cornerstone in modern conformal lymphoma radiotherapy. The use of PET/CT before, during and after chemotherapy has an important impact on the selection of early- and advanced-stage patients who receive radiotherapy. PET/CT is more sensitive for HL staging than CT alone, and the method results in upstaging of a significant proportion of patients. Some studies suggest that this may also result in larger radiotherapy volumes. On the other hand, the more precise determination of disease extent can also be used to allow more patient-tailored and less-toxic radiotherapy to the patients.