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Current Directions in Biomedical Engineering

Joint Journal of the German Society for Biomedical Engineering in VDE and the Austrian and Swiss Societies for Biomedical Engineering

Editor-in-Chief: Dössel, Olaf

Editorial Board: Augat, Peter / Buzug, Thorsten M. / Haueisen, Jens / Jockenhoevel, Stefan / Knaup-Gregori, Petra / Kraft, Marc / Lenarz, Thomas / Leonhardt, Steffen / Malberg, Hagen / Penzel, Thomas / Plank, Gernot / Radermacher, Klaus M. / Schkommodau, Erik / Stieglitz, Thomas / Urban, Gerald A.

CiteScore 2018: 0.47

Source Normalized Impact per Paper (SNIP) 2018: 0.377

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Impact of 4D CT for treatment planning of moving targets: a computer-based biological evaluation

Eike Helf / Oliver Waletzko / Christian Mehrens / Ralf Rohn / Andreas Block
Published Online: 2017-09-07 | DOI: https://doi.org/10.1515/cdbme-2017-0140


This study deals with comparison of conventional and 4D CT (GE Lightspeed) planning on the tumour control probability (TCP), using the TCP model of the AAPM-Report Task Group 166. In the first step a VMAT treatment plan was calculated (Varian Eclipse 13.7) on basis of conventional CT data. This treatment plan was transferred to the complete 4D CT, which represents the tumour volume in motion. Due to the increased volume and the resulting decrease of tumour coverage the TCP went down from 97,6% to 91,2%. After adding an internal target volume (ITV, ICRU 62) to the conventional CT according to our clinical protocols (1,0 cm cc and 0,3 cm axial plane) the TCP increased to 98,0% when applying the conventional plan to the 4D CT. This finding demonstrates the need of 4D CT for moving tumours in chest and abdomen region.

Average IPs with increasing width have been created to evaluate the impact on the TCP and the non-malignant tissue. Our observations had shown that heart, lung and spinal cord radiation exposure did not correlate to chosen respiration segment. This could be explained by the extremely slight ratio of the planning target volume and the irradiated normal tissue.

This procedure enables us to evaluate the efficacy of treatment plans. Furthermore, optimizing trials like the influence of respiration-gated RT, setting individual margins and fitting planning objectives and parameters are still under investigation.

Keywords: 4D CT; tumor control probability; normal tissue complication probability; VMAT; 3D-CRT; treatment planning

About the article

Published Online: 2017-09-07

Citation Information: Current Directions in Biomedical Engineering, Volume 3, Issue 2, Pages 665–668, ISSN (Online) 2364-5504, DOI: https://doi.org/10.1515/cdbme-2017-0140.

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©2017 Eike Helf et al., published by De Gruyter. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License. BY-NC-ND 4.0

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