Maaike G A Schippers1, Gijsbert H Bol1, Astrid A C de Leeuw1, Uulke A van der Heide1, Bas W Raaymakers1, Helena M Verkooijen2, Ina M Jürgenliemk-Schulz3. 1. Department of Radiation Oncology, University Medical Centre Utrecht, The Netherlands. 2. Department of Radiology, University Medical Centre Utrecht, The Netherlands; Julius Center for Health Sciences and Primary Care, University Medical Centre Utrecht, The Netherlands. 3. Department of Radiation Oncology, University Medical Centre Utrecht, The Netherlands. Electronic address: i.m.schulz@umcutrecht.nl.
Abstract
BACKGROUND AND PURPOSE: To evaluate volume changes and position shifts and their contribution to treatment margins of pelvic and para-aortic lymph nodes during Intensity Modulated Radiation Therapy (IMRT) for advanced cervical cancer. MATERIALS AND METHODS: Seventeen patients with visible nodes on MR images underwent T2-weighted MR scans before and weekly during the course of IMRT. Thirty-nine pelvic and para-aortic nodes were delineated on all scans. Margins accommodating for volume and position changes were taken from the boundaries of the nodal volumes in the six main directions. RESULTS: Nodal volume regression from the pre-treatment situation to week 4 was 58% on average (range: 11.7% increase to 100% decrease). Nodal volumes partly increased between the pre-treatment scans and the scans in weeks 1-3, but in week 4 all nodes except one had regressed. Around the nodal volumes manually derived ITV margins accounting for volume changes and position shifts of 7.0, 4.0, 7.0, 8.0, 7.0 and 9.0mm to the medial, lateral, anterior, posterior, superior and inferior directions were needed to cover 95% of all nodes. CONCLUSIONS: We used weekly MR scans to derive inhomogeneous margins that accommodate for nodal volume and position changes during treatment. These margins should be taken into consideration when planning external beam radiotherapy (EBRT) boosts, especially for highly conformal boosting techniques.
BACKGROUND AND PURPOSE: To evaluate volume changes and position shifts and their contribution to treatment margins of pelvic and para-aortic lymph nodes during Intensity Modulated Radiation Therapy (IMRT) for advanced cervical cancer. MATERIALS AND METHODS: Seventeen patients with visible nodes on MR images underwent T2-weighted MR scans before and weekly during the course of IMRT. Thirty-nine pelvic and para-aortic nodes were delineated on all scans. Margins accommodating for volume and position changes were taken from the boundaries of the nodal volumes in the six main directions. RESULTS: Nodal volume regression from the pre-treatment situation to week 4 was 58% on average (range: 11.7% increase to 100% decrease). Nodal volumes partly increased between the pre-treatment scans and the scans in weeks 1-3, but in week 4 all nodes except one had regressed. Around the nodal volumes manually derived ITV margins accounting for volume changes and position shifts of 7.0, 4.0, 7.0, 8.0, 7.0 and 9.0mm to the medial, lateral, anterior, posterior, superior and inferior directions were needed to cover 95% of all nodes. CONCLUSIONS: We used weekly MR scans to derive inhomogeneous margins that accommodate for nodal volume and position changes during treatment. These margins should be taken into consideration when planning external beam radiotherapy (EBRT) boosts, especially for highly conformal boosting techniques.
Authors: Dennis Winkel; Anita M Werensteijn-Honingh; Petra S Kroon; Wietse S C Eppinga; Gijsbert H Bol; Martijn P W Intven; Hans C J de Boer; Louk M W Snoeren; Jochem Hes; Bas W Raaymakers; Ina M Jürgenliemk-Schulz Journal: Clin Transl Radiat Oncol Date: 2019-03-30
Authors: Dennis Winkel; Gijsbert H Bol; Anita M Werensteijn-Honingh; Ilse H Kiekebosch; Bram van Asselen; Martijn P W Intven; Wietse S C Eppinga; Bas W Raaymakers; Ina M Jürgenliemk-Schulz; Petra S Kroon Journal: Phys Imaging Radiat Oncol Date: 2019-03-01
Authors: Lisa Durrant; Maxwell Robinson; Maria A Hawkins; Frank Van den Heuvel; Rebecca Muirhead Journal: Radiother Oncol Date: 2016-08-28 Impact factor: 6.280