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Updated: Jan 12, 2026
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
Tomotherapy megavoltage computed tomography for lung tumor positioning and contouring
Ruth Rodríguez-Romero1, Patricia Sánchez-Rubio1, Luis Alejo Luque2
1Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Puerta de Hierro Majadahonda, Madrid, Spain.
Background:
The study aim was to evaluate the usefulness of tomotherapy megavoltage computed tomography (MVCT) as "slow" CT for both positioning and contouring lung tumors.
Materials And Methods:
Cranio-caudal motion of a pulmonary lesion was simulated by using a QUASAR phantom for different breathing periods (2-10 s) and cycles (sine and cosine-fourth-power). Coronal and sagittal MVCT reconstructions were analyzed, and Dice similarity coefficients were obtained to compare the expected motion-encompassing volumes with the segmented volumes.
Results:
Despite motion artifacts in axial slices, the coronal and sagittal midplanes allowed delineation of the internal treatment volume, except when the breathing period was equal to the acquisition time (5 s). In that case, an aliasing artifact prevented applying proper delimitation. The highest similarity coefficient (> 0.9) was obtained for the lowest CT spacing (2 mm) and the shortest breathing period.
Conclusions:
For periodic breath patterns, Tomotherapy MVCT can be used for positioning and cranio-caudal length contour delineation of lung tumors in motion.
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