PT  - JOURNAL ARTICLE
AU  - Paul Martin Putora
AU  - Marciana Nona Duma
AU  - Florent Baty
AU  - Michal Devecka
AU  - Martin Brutsche
AU  - Ludwig Plasswilm
TI  - Assessment of tumor size and movement trajectories using CT scans with different pitch settings
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P658
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P658.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P658.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Introduction: Pitch Settings of CT scanners have an influence on the way moving lesions are reconstructed. These images have an impact on target definition in radiotherapy planning, therefore the Planning-CT settings are of central importance for correct tumor irradiation and normal tissue sparing.Method: A water filled 40mm table tennis ball serving as a tumor phantom was moved along an elipsoid trajectory by a custom-assembled Lego(c) based device with a cycle duration of 4.2 seconds. The pitch/slice settings tested were termed "fast" (2.5mm, standard pitch), "intermediate" (2.5mm, half pitch), and "slow" (0.625mm, half pitch).Results: The volume of the ball was overestimated with the volume of the tumor-phantom growing from 82% for the fast CT, 171% for the intermediate CT and 300% for the slow CT. The phantom trajectory could best be reconstructed in the slow CT. The different sizes can be seen here:Conclusion: The custom lung phantom proved to work well for the specified task. The effect of CT settings during planning-CT acquisition on the resulting volumes was significant. Acquisition of slow-CT images for radiotherapy planning enables a better targeting of the moving tumor and sparing of normal lung tissue specifically when respiratory gating is not available.