Abstract
Background and purpose
Patient immobilization during brain tumor radiotherapy is achieved by employing different mask systems. Two innovative mask systems were developed to minimize the problems of claustrophobic patients. Our aim was to evaluate whether the quality of patient immobilization using the new mask systems was equivalent to the standard mask system currently in use.
Material and methods
Thirty-three patients with cerebral target volumes were irradiated using the Hi-Art II tomotherapy system between 2010 and 2012. Each group of 11 patients was fitted with one of the two new mask systems (Crystal® or Open Face® mask, Orfit) or the standard three-point mask (Raycast®-HP, Orfit) and a total of 557 radiotherapy fractions were evaluated. After positioning was checked by MV-CT, the necessary table adjustments were noted. Data were analyzed by comparing the groups, and safety margins were calculated for nonimage-guided irradiation.
Results
The mean values of the table adjustments were: (a) lateral (mm): − 0.22 (mask 1, standard deviation (σ): 2.15); 1.1 (mask 2, σ: 2.4); − 0.64 (mask 3, σ: 2.9); (b) longitudinal (mm): − 1 (mask 1, σ: 2.57); − 0.5 (mask 2, σ: 4.7); − 1.22 (mask 3, σ: 2.52); (c) vertical (mm): 0.62 (mask 1, σ: 0.63); 1.2 (mask 2, σ: 1.0); 0.57 (mask 3, σ: 0.28); (d) roll: 0.35° (mask 1, σ: 0.75); 0° (mask 2, σ: 0.8); 0.02° (mask 3, σ: 1.12). The outcomes suggest necessary safety margins of 5.49–7.38 mm (lateral), 5.4–6.56 mm (longitudinal), 0.82–3.9 mm (vertical), and 1.93–4.5° (roll). There were no significant differences between the groups.
Conclusions
The new mask systems improve patient comfort while providing consistent patient positioning.
Zusammenfassung
Hintergrund und Ziel
Die Patientenpositionierung bei der Bestrahlung von zerebralen Zielvolumina erfolgt durch verschiedene Maskenarten. Um Patienten mit Klaustrophobie die Durchführung der täglichen Bestrahlung zu erleichtern, wurden zwei innovative Maskensysteme entwickelt. Unser Ziel war es, zu überprüfen, ob die Qualität der Lagerung der des bislang genutzten Standardmaterials entspricht.
Methodik
Von 2010 bis 2012 wurden 33 Patienten mit zerebralen Zielvolumina am Tomotherapie-Hi-Art-II-System bestrahlt. Die Fixation erfolgte für jeweils 11 Patienten mit zwei verschiedenen neuen Maskensystemen (Crystal®- oder Open-Face®-Maske, Orfit) oder einer Standard-3-Punkt-Maske (Raycast©-HP, Orfit). Ausgewertet wurden 557 Fraktionen. Die täglichen, sich aus dem MV-CT ergebenden Verschiebungen wurden im Vergleich der Gruppen analysiert und die sich ergebenden Sicherheitssäume für Bestrahlungen ohne vorherige Bildgebung berechnet.
Ergebnisse
Im Mittel waren folgende Tischverschiebungen notwendig: (a) Lateral [mm]: − 0,22 (Maske 1, Standardabweichung [σ]: 2,15), 1,1 (Maske 2, σ: 2,4), − 0,64 (Maske 3, σ: 2,9); (b) Longitudinal [mm]: − 1 (Maske 1, σ:2,57), − 0,5 (Maske 2, σ: 4,7); − 1,22 (Maske 3, σ: 2,52); (c) Vertikal [mm]: 0,62 (Maske 1, σ: 0,63), 1,2 (Maske 2, σ: 1,0), 0,57 (Maske 3, σ: 0,28); (d) Roll: 0,35° (Maske 1, σ: 0,75), 0° (Maske 2, σ: 0,8), 0,02° (Maske 3, σ: 1,12). Daraus resultieren notwendige Sicherheitssäume von 5,49–7,38 mm (lateral), 5,4–6,56 mm (longitudinal), 0,82–3,9 mm (vertikal) und 1,93–4,5° (roll). Ein signifikanter Unterschied zwischen den Gruppen existiert nicht.
Schlussfolgerung
Die neuen Maskenmaterialien verbessern den Patientenkomfort bei gleicher Qualität in Bezug auf die Patientenlagerung.
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Acknowledgments
The authors want to thank Mrs. Emilie Cuypers and Mr. Manfred Peinemann for expert application support with the mask materials.
Compliance with ethical guidelines
Conflict of interest. C. Leitzen, T. Wilhelm-Buchstab, S. Garbe, C. Lütter, T. Müdder, B. Simon, H.H. Schild, and H. Schüller state the following: This work was supported by Orfit Industries, Belgium, with free mask materials. All studies on humans described in the present manuscript were carried out with the approval of the responsible ethics committee and in accordance with national law and the Helsinki Declaration of 1975 (in its current, revised form). Informed consent was obtained from all patients included in studies.
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Leitzen, C., Wilhelm-Buchstab, T., Garbe, S. et al. Quality of patient positioning during cerebral tomotherapy irradiation using different mask systems. Strahlenther Onkol 190, 382–385 (2014). https://doi.org/10.1007/s00066-013-0496-x
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DOI: https://doi.org/10.1007/s00066-013-0496-x