Image-Guided Stereotactic Body Radiotherapy for Lung Tumors Using BodyLoc With Tomotherapy: Clinical Implementation and Set-Up Accuracy
- Center for Cancer Treatment, Sharp Grossmont Hospital, La Mesa, CA (United States)
We investigated the use of a BodyLoc immobilization and stereotactic localization device combined with TomoTherapy megavoltage CT (MVCT) in lung stereotactic body radiotherapy (SBRT) to reduce set-up uncertainty and treatment time. Eight patients treated with 3-5 fractions of SBRT were retrospectively analyzed. A BodyLoc localizer was used in both CT simulation for localization and the initial patient treatment set-up. Patients were immobilized with a vacuum cushion on the back and a thermoplastic body cast on the anterior body. Pretreatment MVCT from the TomoTherapy unit was fused with the planning kilovoltage CT (KVCT) before each fraction of treatment to determine interfractional set-up error. The comparison of two MVCTs during a fraction of treatment resulted in the intrafractional uncertainty of the treatment. A total of 224 target isocenter shifts were analyzed to assess these inter- and intrafractional tumor motions. We found that for interfractional shifts, the mean set-up errors and standard deviations were -1.1 {+-} 2.8 mm, -2.5 {+-} 8.7 mm, and 4.1 {+-} 2.6 mm, for lateral, longitudinal, and vertical variation, respectively; the mean setup rotational variation was -0.3 {+-} 0.7 deg.; and the maximum motion was 13.5 mm in the longitudinal direction. For intrafractional shifts, the mean set-up errors and standard deviations were -0.1 {+-} 0.7 mm, -0.3 {+-} 2.0 mm, and 0.5 {+-} 1.1 mm for the lateral, longitudinal, and vertical shifts, respectively; the mean rotational variation was 0.1 {+-} 0.2 deg.; and the maximum motion was 3.8 mm in the longitudinal direction. There was no correlation among patient characteristics, set-up uncertainties, and isocenter shifts, and the interfractional set-up uncertainties were larger than the intrafractional isocenter shift. The results of this study suggested that image-guided stereotactic body radiotherapy using the BodyLoc immobilization system with TomoTherapy can improve treatment accuracy.
- OSTI ID:
- 21333963
- Journal Information:
- Medical Dosimetry, Vol. 35, Issue 1; Other Information: DOI: 10.1016/j.meddos.2008.12.003; PII: S0958-3947(08)00204-5; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0958-3947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Clinical benefits of new immobilization system for hypofractionated radiotherapy of intrahepatic hepatocellular carcinoma by helical tomotherapy
Analysis of Daily Setup Variation With Tomotherapy Megavoltage Computed Tomography