3519 - ICD Coding an 3D Target Volume Definitions for Benign Diseases: An International Delphi Consensus Process
Presenter(s)
H. M. Seegenschmiedt1, D. R. Steike2, T. Weissmann3, R. E. Shaffer4, J. Kriz5, F. Cellini6, N. S. Koneru7, M. G. Trombetta8, A. Montero9, B. Álvarez10, and R. Hernanz11; 1Ruhrradiologie RUE191 - Strahlentherapie, Essen, Hamburg, Germany, 2Department of Radiotherapy – Radiooncology , University Hospital Münster, Germany, Münster, Germany, 3Department of Radiation Oncology, University Hospital of Erlangen, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen, Germany, 4Xstrahl, Suwanee, United Kingdom, 5Radiation Oncology Clemens Hospital Muenster, Muenster, Germany, 6Polo Scienze Oncologiche ed Ematologiche, Istituto di Radiologia, Università Cattolica del Sacro Cuore-Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy, 7Radiation Oncology and Radiation Medicine FHN Memorial Hospital, Chicago, IL, 8Division of Radiation Oncology, Allegheny General Hospital, Drexel University College of Medicine, Pittsburgh, Pittsburgh, PA, 9Department of Radiation Oncology, HM Hospitales, Madrid, Spain, 10Department of Radiation Oncology , HM Hospitales, Madrid, Spain, Madrid, Spain, 11Department of Radiation Oncology, Hospital Ramón y Cajal and Genesis Care Madrid, Madrid, Spain
Purpose/Objective(s): Radiotherapy of benign diseases using low-dose irradiation (LDRT) is a well-established therapeutic procedure , but is controversially discussed internationally due to heterogeneous definitions and diverging clinical studies. A systematic recording of the ICD definitions , exact definition of 3D irradiation volumes and optimal imaging per region as part of a Delphi project with international expert consensus should create new foundations for optimized clinical studies.
Materials/Methods: A comprehensive systematic recording of all ICD10 definitions, the implementation of the Cartesian space and a clear definition for isocenter, GTV ( Gross Target Volume ), CTV and PTV as well as the provision of a whole-body CT data set "Homunculus" allowed the recording and comparative assessment of at least 12 different target volumes, initially for odteoarthroses and tendino- and bursopathies.
Results: From the data sets, the institutes' mean values with the deviations in the three axes x, y , z were determined for the individual regions and diseases. As an example, the anatomical isocenter of gonarthrosis is in the middle of the tibial tuberosity. In addition to the representation of pathological regions (GTV), the CTV is defined based on relevant clinical structures (joint capsule, bursa and tendon with surrounding inflammatory reaction ( inMRI ). Depending on the region, the PTV is formed with a safety margin of 0.3 - 0.5 cm from the CTV minus the skin boundaries. The data adapted to the anatomy of the homunculus (see figure) change depending on the anatomy of the affected patient. They provide orientation for the systematics for expanded application to individual CT-based radiation target volumes.
Conclusion: Isocenter - oriented, anatomically variable 3D planning provides a better understanding of the underlying pathologies of osteoarthritis. This is an important prerequisite for further evidence of LDRT with a focus on individual joint osteoarthritis taking into account imaging and clinical examination.