Traditional and modern techniques for radiation treatment planning

Before the advent of effective chemotherapy for Hodgkin lymphoma (HL) extensive radiation fields (subtotal or total nodal irradiation) were used. The techniques for delivering these very large treatment fields were developed, and they are still used occasionally in special situations. With modern combined modality treatment of the majority of patients with HL radiation fields have become much smaller and focused on the initially involved lymphoma tissue. Involved-field radiotherapy (IFRT) has been widely used for the past 15-20 years. It implies treating involved lymph node regions or lymph node groups, and definitions of these targets have varied somewhat. With modern techniques such as CT- or even PET/CT-based treatment planning, co-registration between pre-chemotherapy and planning scans, conformal radiotherapy techniques such as 3D conformal radiotherapy or intensity-modulated radiotherapy (IMRT), and respiratory gating, even more conformal treatment, involved-node radiotherapy (INRT), is now being introduced worldwide. The goal is to maintain the high efficacy of radiotherapy in the treatment of HL while avoiding as much as possible irradiating normal tissues.