<abstract xmlns="http://www.w3.org/1999/xhtml"><italic>Purpose:</italic> To evaluate the breathing amplitude, tumor motion, patient positioning, and treatment volumes among consecutive four-dimensional computed tomography (4D-CT) scans, during the simulation for lung stereotactic body radiation therapy (SBRT).<italic>Material and methods:</italic> The variation and shape of the breathing amplitude, patient positioning, and treatment volumes were evaluated for 55 lung cancer patients after consecutive 4D-CT acquisitions, scanned at one-week intervals. The impact of variation in the breathing amplitude on lung tumor motion was determined for 20 patients. The gross tumor volume (GTV) was contoured from a free-breathing CT scan and at ten phases of the respiratory cycle, for both 4D-CTs (440 phases in total).<italic>Results:</italic> Breathing amplitude decreased by 3.6 (3.4-4.9) mm, tumor motion by 3.2 (0.4-5.0) mm while breathing period increased by 4 (2-6) s, inter-scan for 20 patients. Intra-scan variation was 4 times greater for the breathing amplitude, 5 times for the breathing period, and 8 times for the breathing cycle, comparing irregular versus regular breathing patterns for 55 patients. Using coaching, the breathing amplitude increases 3 to 8 mm, and the breathing period 2 to 6 s. Differences in the contoured treatment volumes were less than 10% between consecutive scans. Patient positioning remained stable, with a small inter-scan difference of 1.1 (0.6-1.4) mm.<italic>Conclusion:</italic> Decreasing the inter-scan breathing amplitude decreases the tumor motion reciprocally. When the breathing amplitude decreases, the breathing period increases at inter- and intra-scan, especially during irregular breathing. Coaching improves respiration, keeping the initial shape of the breathing amplitude. Contoured treatment volumes and patient positioning were reproducible through successive scans.</abstract>

Purpose: To evaluate the breathing amplitude, tumor motion, patient positioning, and treatment volumes among consecutive four-dimensional computed tomography (4D-CT) scans, during the simulation for lung stereotactic body radiation therapy (SBRT).Material and methods: The variation and shape of the breathing amplitude, patient positioning, and treatment volumes were evaluated for 55 lung cancer patients after consecutive 4D-CT acquisitions, scanned at one-week intervals. The impact of variation in the breathing amplitude on lung tumor motion was determined for 20 patients. The gross tumor volume (GTV) was contoured from a free-breathing CT scan and at ten phases of the respiratory cycle, for both 4D-CTs (440 phases in total).Results: Breathing amplitude decreased by 3.6 (3.4-4.9) mm, tumor motion by 3.2 (0.4-5.0) mm while breathing period increased by 4 (2-6) s, inter-scan for 20 patients. Intra-scan variation was 4 times greater for the breathing amplitude, 5 times for the breathing period, and 8 times for the breathing cycle, comparing irregular versus regular breathing patterns for 55 patients. Using coaching, the breathing amplitude increases 3 to 8 mm, and the breathing period 2 to 6 s. Differences in the contoured treatment volumes were less than 10% between consecutive scans. Patient positioning remained stable, with a small inter-scan difference of 1.1 (0.6-1.4) mm.Conclusion: Decreasing the inter-scan breathing amplitude decreases the tumor motion reciprocally. When the breathing amplitude decreases, the breathing period increases at inter- and intra-scan, especially during irregular breathing. Coaching improves respiration, keeping the initial shape of the breathing amplitude. Contoured treatment volumes and patient positioning were reproducible through successive scans.

The assessment of consecutive 4D-CT scans during simulation for lung stereotactic body radiation therapy patients

Polish Journal of Medical Physics and Engineering

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Purpose: To evaluate the breathing amplitude, tumor motion, patient positioning, and treatment volumes among consecutive four-dimensional computed tomography...

The assessment of consecutive 4D-CT scans during simulation for lung stereotactic body radiation therapy patients

Published Online: Dec 24, 2020

Page range: 193 - 199

DOI: https://doi.org/10.2478/pjmpe-2020-0023

Keywords
lung cancer, breathing amplitude, tumor motion, 4D-CT, SBRT

© 2020 Milovan Savanovic et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

The assessment of consecutive 4D-CT scans during simulation for lung stereotactic body radiation therapy patients

Published Online: Dec 24, 2020

Page range: 193 - 199

DOI: https://doi.org/10.2478/pjmpe-2020-0023

Keywordslung cancer, breathing amplitude, tumor motion, 4D-CT, SBRT

© 2020 Milovan Savanovic et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
lung cancer, breathing amplitude, tumor motion, 4D-CT, SBRT