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Updated: Apr 20, 2026
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
Intra thoracic anatomical changes in lung cancer patients during the course of radiotherapy
Margriet Kwint1, Sanne Conijn1, Eva Schaake1
1Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Background And Purpose:
Conebeam-CT (CBCT) guidance is often used for setup verification of lung cancer patients treated with radiotherapy. The purpose of this study was to quantify intra-thoracic anatomical changes (ITACs) during the radiotherapy treatment and to hand over a decision support system to guide the radiation therapy technologist and radiation oncologist in prioritizing these changes.
Materials And Methods:
1793 CBCT-scans of 177 lung cancer patients treated in 2010 in our institute with radical radiotherapy were evaluated. Our decision support system: "the Traffic Light Protocol", was retrospectively applied to these CBCT-scans. The protocol has four levels: red (immediate action before treatment), orange (action before next fraction), yellow (no action required) and green (no change).
Results:
In 128 patients (72%), 210 ITACs were observed with a maximum level of red, orange and yellow in 12%, 36% and 24% respectively. Types of observed ITACs were, tumor regression (35%), tumor baseline shift (27%), changes in atelectasis (19%), tumor progression (10%), pleural effusion (6%) and infiltrative changes (3%).
Conclusions:
ITACs have been observed in 72% of all lung cancer patients during the course of radical radiotherapy. The clinical relevance of the proposed ITAC classification in lung radiotherapy needs to be validated in a prospective analysis.
