Contouring aid tools in radiotherapy. Smoothing: the false friend

• Jordi Marruecos Querol ^[1] ; Aranzazu Eraso Urien ^[1] ; Diego Jurado Bruggeman ^[2] ; Anna Lopez Vidal ^[3] ; Jordi Rubió Casadevall ^[3] ; Ricard Mesía Nin ^[4] ; Maria Buxó ^[5]
  1. [1] Radiation Oncology Department, Catalan Institute of Oncology, Girona, Spain
  2. [2] Research Group in Radiation Oncology and Medical Physics of Girona, Girona Biomedical Research Institute (IDIBGI), Girona, Spain
  3. [3] Medical Oncology Department, Catalan Institute of Oncology, Girona, Spain
  4. [4] Medical Oncology Department, Catalan Institute of Oncology, B-ARGO Group, IGTP, Badalona, Spain
  5. [5] Girona Biomedical Research Institute (IDIBGI), Girona, Spain

  Mostrar afiliaciones +
• Localización: Clinical & translational oncology, ISSN 1699-048X, Vol. 26, Nº. 8, 2024, págs. 1956-1967
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Objective Contouring accuracy is critical in modern radiotherapy. Several tools are available to assist clinicians in this task. This study aims to evaluate the performance of the smoothing tool in the ARIA system to obtain more consistent volumes.

    Methods Eleven different geometric shapes were delineated in ARIA v15.6 (Sphere, Cube, Square Prism, Six-Pointed Star Prism, Arrow Prism, And Cylinder and the respective volumes at 45° of axis deviation (_45)) in 1, 3, 5, 7, and 10 cm side or diameter each. Post-processing drawing tools to smooth those first-generated volumes were applied in different options (2D-ALL vs 3D) and grades (1, 3, 5, 10, 15, and 20). These volumetric transformations were analyzed by comparing different parameters: volume changes, center of mass, and DICE similarity coefficient index. Then we studied how smoothing affected two different volumes in a head and neck cancer patient: a single rounded node and the volume delineating cervical nodal areas.

    Results No changes in data were found between 2D-ALL or 3D smoothing. Minimum deviations were found (range from 0 to 0.45 cm) in the center of mass. Volumes and the DICE index decreased as the degree of smoothing increased. Some discrepancies were found, especially in figures with cleft and spikes that behave differently. In the clinical case, smoothing should be applied only once throughout the target delineation process, preferably in the largest volume (PTV) to minimize errors.

    Conclusion Smoothing is a good tool to reduce artifacts due to the manual delineation of radiotherapy volumes. The resulting volumes must be always carefully reviewed.