Elena Villaggi1, Victor Hernandez2, Marco Fusella3, Eugenia Moretti4, Serenella Russo5, Elena Maria Luisa Vaccara6, Barbara Nardiello7, Marco Esposito5, Jordi Saez8, Savino Cilla9, Carmelo Marino10, Michele Stasi11, Pietro Mancosu12. 1. Medical Physics Unit, Azienda Unità Sanitaria Locale di Piacenza, Italy. Electronic address: e.villaggi@ausl.pc.it. 2. Hospital Universitari Sant Joan de Reus, Department of Medical Physics, Tarragona, Spain. 3. Medical Physics Department, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy. 4. Department of Medical Physics, Azienda Sanitaria Universitaria Integrata di Udine, Italy. 5. Medical Physics Unit, Azienda USL Toscana Centro, Firenze I-50012, Italy. 6. Policlinico San Martino Hospital, Health Physics Structure, Genova, Italy. 7. UPMC San Pietro FBF, Roma, Italy. 8. Hospital Clinic de Barcelona, Department of Radiation Oncology, Barcelona, Spain. 9. Medical Physics Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy. 10. Humanitas C.C.O., Catania, Italy. 11. Department of Medical Physics, Azienda Ospedaliera Ordine Mauriziano di Torino, Turin, Italy. 12. Medical Physics Unit of Radiation Oncology Dept., Humanitas Research Hospital, Milano, Italy.
Abstract
PURPOSE: To evaluate, in a multi-institutional context, the role of Dose Volume Histogram (DVH) sharing in order to achieve higher plan quality, to harmonize prostate Stereotactic Body Radiation Therapy (SBRT) plans and to assess if the planner's experience in SBRT could lead to lower dose at organs at risk (OARs). METHODS: During the first phase five patients enrolled for prostate SBRT were planned by multiple physicists according to common protocol. The prescription dose was 35 Gy in 5 fractions. Dosimetric parameters, modulation index (MIt), plan parameters, and planner experience level (EL) were statistically analyzed. During the second phase median DVHs from all centers were shared and physicists replanned one patient of the five, aiming at inter-planner harmonization and further OARs sparing. Data were summarized by Spearman-correlogram (p < 0.05) and boxplots. The Kruskal-Wallis test was used to compare the re-plans to the original plans. RESULTS: Seventy-eight SBRT plans from 13 centers were evaluated. EL correlated with modulation of plan parameters and reduction of OARs doses, such as volume receiving 28 Gy of rectum (rectum-V28Gy), rectum-V32Gy, and bladder-V30Gy. The re-plans showed significant reduced variability in rectum-V28Gy and increased PTV dose homogeneity. No significant difference in plan complexity metrics and plan parameters between plans and re-plans were obtained. CONCLUSIONS: Planner's experience in prostate SBRT was correlated with dosimetric parameters. Sharing median DVHs reduced variability among centers whilst keeping the same level of plan complexity. SBRT planning skills can benefit from a replanning phase after sharing DVHs from multiple centers, improving plan quality and concordance among centers.
PURPOSE: To evaluate, in a multi-institutional context, the role of Dose Volume Histogram (DVH) sharing in order to achieve higher plan quality, to harmonize prostate Stereotactic Body Radiation Therapy (SBRT) plans and to assess if the planner's experience in SBRT could lead to lower dose at organs at risk (OARs). METHODS: During the first phase five patients enrolled for prostate SBRT were planned by multiple physicists according to common protocol. The prescription dose was 35 Gy in 5 fractions. Dosimetric parameters, modulation index (MIt), plan parameters, and planner experience level (EL) were statistically analyzed. During the second phase median DVHs from all centers were shared and physicists replanned one patient of the five, aiming at inter-planner harmonization and further OARs sparing. Data were summarized by Spearman-correlogram (p < 0.05) and boxplots. The Kruskal-Wallis test was used to compare the re-plans to the original plans. RESULTS: Seventy-eight SBRT plans from 13 centers were evaluated. EL correlated with modulation of plan parameters and reduction of OARs doses, such as volume receiving 28 Gy of rectum (rectum-V28Gy), rectum-V32Gy, and bladder-V30Gy. The re-plans showed significant reduced variability in rectum-V28Gy and increased PTV dose homogeneity. No significant difference in plan complexity metrics and plan parameters between plans and re-plans were obtained. CONCLUSIONS: Planner's experience in prostate SBRT was correlated with dosimetric parameters. Sharing median DVHs reduced variability among centers whilst keeping the same level of plan complexity. SBRT planning skills can benefit from a replanning phase after sharing DVHs from multiple centers, improving plan quality and concordance among centers.
Authors: L Wilke; C Moustakis; O Blanck; D Albers; C Albrecht; Y Avcu; R Boucenna; K Buchauer; T Etzelstorfer; C Henkenberens; D Jeller; K Jurianz; C Kornhuber; M Kretschmer; S Lotze; K Meier; P Pemler; A Riegler; A Röser; D Schmidhalter; K H Spruijt; G Surber; V Vallet; R Wiehle; J Willner; P Winkler; A Wittig; M Guckenberger; S Tanadini-Lang Journal: Strahlenther Onkol Date: 2021-07-01 Impact factor: 3.621