{"id":14358,"date":"2026-03-12T07:50:48","date_gmt":"2026-03-12T10:50:48","guid":{"rendered":"https:\/\/rtmedical.com.br\/tmp-en-1773312646289\/"},"modified":"2026-04-04T18:08:29","modified_gmt":"2026-04-04T21:08:29","slug":"lymphoma-target-delineation","status":"publish","type":"post","link":"https:\/\/rtmedical.com.br\/en\/lymphoma-target-delineation\/","title":{"rendered":"Hodgkin & Non-Hodgkin Lymphoma: RT Delineation"},"content":{"rendered":"

Radiation Therapy for Lymphoma: From EFRT to Modern ISRT<\/h2>\n

Target delineation and field setup for lymphoma radiation therapy have undergone a remarkable evolution. Extended-field radiation therapy (EFRT), once the mainstay of definitive treatment without chemotherapy, gave way to involved-field radiation therapy (IFRT) as combined modality therapy became standard. Today, involved-site radiation therapy (ISRT) \u2014 which further reduces volumes based on 3D anatomy and the original disease extent \u2014 is the recommended approach per ILROG guidelines.<\/p>\n

\"Axial
Figure 31.1 \u2014 Stage IIA HL: pre-chemo GTV (red) and ISRT CTV (green) on simulation CT. Source: Target Volume Delineation and Field Setup, 2nd Edition<\/figcaption><\/figure>\n

ISRT emerged over the past decade from ongoing efforts to minimize late treatment effects and improve quality of life for survivors. When patients are seen by the radiation oncologist prior to diagnostic imaging, involved-node radiation therapy (INRT) can be employed. INRT and ISRT share similar delineation principles, but ISRT margins must be larger to account for uncertainties in contouring the CTV when optimal pre-treatment imaging is unavailable.<\/p>\n

INRT is the common approach in Europe where a pre-chemotherapy PET-CT in treatment position is routine. In North America, where such imaging often is not available in the radiation therapy position, ISRT remains standard practice. For a comprehensive overview of delineation approaches across all disease sites, see our complete guide to target volume delineation<\/a>.<\/p>\n

Delineation Principles: GTV, CTV, ITV, and PTV<\/h2>\n

ISRT simulation requires 3D planning \u2014 CT simulator, PET\/CT simulator, or MRI simulator. IV contrast should be used whenever the patient’s condition allows to accurately identify vessels. When RT serves as consolidation after chemotherapy, both pre- and post-chemotherapy FDG-PET and CT should ideally be fused with the simulation CT in the planning system.<\/p>\n

Delineation follows the ICRU Report 83 nomenclature:<\/p>\n