Stereotactic radiotherapy using tomotherapy for early-stage non-small cell lung carcinoma: analysis of intrafraction tumour motion.

Academic Article

Abstract

  • INTRODUCTION: Intrafraction tumour motion in helical tomotherapy was investigated by comparing pre- and mid-fraction CT scans in patients with early non-small cell lung carcinoma (NSCLC) to assess the efficacy of a 7-mm margin around gross tumour volumes (GTVs) in stereotactic body radiation therapy (SBRT). METHODS: Thirty patients with early-stage NSCLC received SBRT in four or five fractions for a total of 141 treatments. A slow positron emission tomography/CT scan was fused with the simulation CT to determine the GTV. A planning target volume was created by placing an isotropic margin of 7 mm around the GTV. Data were retrospectively analyzed to assess translational tumour positional changes along the x, y and z axes and vector changes in millimeters from the pretreatment megavoltage (MV)-CT to the mid-fraction MV-CT. RESULTS: Average movements for all 141 treatment days along the x, y and z axes were 0.5 ± 2.3, -0.3 ± 3.0 and 0.9 ± 3.0 mm, respectively. Average movements for each patient along the x, y and z axes were 0.5 ± 1.5, -0.2 ± 2.0 and 0.9 ± 1.9 mm, respectively. Average vector displacement was 4.3 ± 2.4 mm for all treatment days and 4.2 ± 1.7 mm for each patient. Of 141 treatments, 137 (97.2%) fell within 7.0 mm in all axes. CONCLUSION: The addition of a 7-mm margin to the GTV for patients receiving SBRT for NSCLC using tomotherapy is adequate to account for tumour movement. Mid-fraction CT scans proved to be valuable in assessing intrafraction tumour motion.
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    Keywords

  • SBRT, early-stage lung cancer, intrafraction, tomotherapy, tumour motion, Aged, Aged, 80 and over, Carcinoma, Non-Small-Cell Lung, Dose Fractionation, Radiation, Female, Humans, Imaging, Three-Dimensional, Lung Neoplasms, Male, Middle Aged, Motion, Neoplasm Staging, Patient Positioning, Radiosurgery, Radiotherapy Setup Errors, Radiotherapy, Image-Guided, Radiotherapy, Intensity-Modulated, Reproducibility of Results, Sensitivity and Specificity, Tomography, X-Ray Computed, Treatment Outcome
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    Author List

  • Boggs DH; Feigenberg S; Walter R; Wissing D; Patel B; Wu T; Rosen L
  • Start Page

  • 706
  • End Page

  • 713
  • Volume

  • 58
  • Issue

  • 6