3541 - 3-Dimensional Treatment Planning and Target Volume Definition of Osteoarthritis - Recommendations of the International Benign Target Volume Peer Group
Presenter(s)
D. R. Steike1, H. M. Seegenschmiedt2, T. Weissmann3, R. E. Shaffer4,5, J. Kriz6, F. Pascher6, A. M. Thole7, F. Linke8, C. Wimmer9, A. Montero10, B. Alvarez10, R. Hernanz de Lucas11, A. Sotoca12, H. A. Gaona3, S. Gomez Ordonez13, F. Cellini14, G. Reinartz1, N. S. Koneru15, M. G. Trombetta16, and H. T. Eich1; 1Department of Radiation Therapy – Radiation Oncology, University Hospital of Muenster, Muenster, Germany, 2Strahlentherapie, MVZ Ruhrradiologie Rü191 Essen, Essen, Deutschland, Essen, Deutschland, Essen, Germany, 3Department of Radiation Oncology, University Hospital of Erlangen, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen, Germany, 4GenesisCare UK, London, United Kingdom, 5Department of Oncology, St Luke's Cancer Centre, Royal Surrey Hospital, Guildford, United Kingdom, 6Radiation Oncology Clemens Hospital Muenster, Muenster, Germany, 7RadioOnkologieNetzwerk, Radiation Therapy Osnabrueck, Osnabrueck, Germany, 8RadioOnkologieNetzwerk, Radiation Therapy Ostalb, Aalen, Germany, 9RadioOnkologieNetzwerk, Radiation Therapy Schwaebisch Gmuend, Schwaebisch Gmuend, Germany, 10Department of Radiation Oncology, HM Hospitales, Madrid, Spain, 11Clinic for Radiation Oncology, Hospital Universitario Ramón y Cajal, Madrid, Madrid, Spain, 12Radiation Therapy, Hospital Ruber Internacional Madrid, Madrid, Spain, 13Clinic for Radio-Oncology, Stadtspital Zurich, Zurich, Switzerland, 14Universita Cattolica del Sacro Cuore, Rome, Italy, 15Loyola University Chicago Stritch School of Medicine, National Cancer Institute, Bethesda, Bethesda, IL, 16Division of Radiation Oncology, Allegheny General Hospital, Drexel University College of Medicine, Pittsburgh, Pittsburgh, PA
Purpose/Objective(s):
Low-dose radiotherapy (LDRT) is an established cost-effective and minimal-invasive treatment of osteoarthritis based on a heterogeneous selection of radiobiological and clinical studies currently mainly from Europe. However, systematic recording of 3D radiation volumes requires precise planning definitions for each joint which has not been standardized in the radiotherapeutic treatment of benign conditions yet. In our Delphi project of an international consensus of experts from 15 institutes (Europe and the USA), we propose a systematic 3-D target volume planning to create target volumes that are adapted to the individual joint pathology.Materials/Methods:
Target volume planning for osteoarthritis should be based on the definition of the isocenter and a CT-graphic shift of planning volumes in three planes (x-, y- and z-axis) derived from this. The associated classifications are derived from the radiooncological therapy: GTV (Gross target volume, which includes joint arthrosis), CTV (Clinical target volume includes the extended pathology incl. joint sac/pain region), and PTV (Planning target volume). These volumes were prepared using a standardized homunculus on the individual joints. The homunculus means a uniform CT data set on which the individual target volumes were created by all participating institutes and compared with each other.Results:
From the data, mean values of the institutes with deviations in the three axes were determined for the individual joints. The information on isocenter definition, deviations in the 3 levels and creation of the target volume were compared, discussed and determined within the expert panel. As an example, the anatomical isocenter of coxarthrosis is located in the middle of the caput femoris. In addition to the visualization of pathological regions (GTV), the CTV is defined using the joint capsule caudal to the upper limit of the trochanter minor. The PTV is formed with a safety margin of 0.3 cm to the CTV minus the skin boundaries. From the isocenter, there is a medial displacement of 4.0 cm and a lateral displacement of 7.3 cm (x-axis). Cranially 6.0 cm and caudally 6.4 cm (y-axis). Ventrally 4.3 cm and dorsally 4.8 cm (z-axis). The data adapted to the anatomy of the homunculus changes depending on the anatomy of the patient concerned. They form an orientation of the system for extended application to individual CT-based radiation target volumes.Conclusion:
Radiation treatment of osteoarthritis is an important form of therapy and will also play an increasingly important role in America in the future. A well-thought-out definition of target volumes for radiotherapy of benign diseases is an important prerequisite for further evidence of LDRT with a focus on individual joint arthroses. Isocenter-oriented, anatomically variable 3D planning provides a better understanding of the underlying pathologies of osteoarthritis.