title: Lung and liver SBRT using helical tomotherapy--a dosimetric comparison of fixed jaw and dynamic jaw delivery.
abstract: The purpose of the study was to evaluate the time effectiveness and dose distribution details of dynamic jaw delivery compared to the regular helical tomotherapy delivery mode in stereotactic body radiation therapy (SBRT) of liver and lung tumors. Ten patients with liver and ten patients with lung tumors were chosen to analyze the dose profiles and treatment times of regular helical tomotherapy delivery (2.5cm field width) and new helical tomotherapy mode using dynamic jaw delivery with 5 cm field width. A median dose between 24 and 30 Gy was delivered in a single fraction. Regular helical tomotherapy took an average of 31.9 ± 6.7 min (lung SBRT) and 41.7 ± 15.0 min (liver SBRT). A reduction in delivery duration of 38.8% to 19.5± 2.9 min could be accomplished for lung irradiation (p < 0.05) and by 50.8% to 20.5 ± 6.0 min for liver SBRT (p < 0.05). Target coverage, as well as conformity and uniformity indices, showed no significant differences. No significant increase in organs-at-risk exposure could be detected either for lung or liver tumors. Therefore, use of new delivery mode with dynamic jaws improves treatment efficiency by reducing beam-on time, while maintaining excellent planquality.
authors.affiliation: University of Heidelberg. lfetzner@hotmail.com.
authors.forename: Leonie
authors.initials: L
authors.lastname: Rudofsky
authors.forename: Eleanor
authors.initials: E
authors.lastname: Aynsley
authors.forename: Sebastian
authors.initials: S
authors.lastname: Beck
authors.forename: Kai
authors.initials: K
authors.lastname: Schubert
authors.forename: Gregor
authors.initials: G
authors.lastname: Habl
authors.forename: Sonja
authors.initials: S
authors.lastname: Krause
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
authors.forename: Florian
authors.initials: F
authors.lastname: Sterzing
mesh_terms: D019583:Dose Fractionation, Radiation; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011874:Radiometry / Q000379:methods; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061089:Radiotherapy, Image-Guided; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*