Three-dimensional accuracy and interfractional reproducibility of patient fixation and positioning using a stereotactic head mask system

Karger, Christian P.; Jäkel, Oliver; Debus, Jürgen; Kühn, Sabine; Hartmann, Günther H.

doi:10.1016/s0360-3016(00)01562-5

Cited by 101 publications

(71 citation statements)

References 19 publications

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“…To achieve the required levels of setup accuracy, image guidance and a thermoplastic mask attached to the treatment couch are used in place of an invasive head frame. Previous works have shown that intra‐fractional positioning accuracy of mask‐based immobilization systems range from 1.59 ± 0.84 mm to 4.7 ± 1.7 mm using a thermoplastic mask and image guidance from Cone‐beam CT (CBCT), CT simulation, portal images, and biplanar diagnostic x ray 2, 3, 4, 5. These positioning errors are still too large for SRS treatments, due to irradiating critical organs during the treatment.…”

Section: Introductionmentioning

confidence: 99%

Monitoring frequency of intra‐fraction patient motion using the ExacTrac system for LINAC‐based SRS treatments

Lewis

Snyder

Kim

et al. 2018

J Applied Clin Med Phys

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PurposeThe aim of this study was to investigate the intra‐fractional patient motion using the ExacTrac system in LINAC‐based stereotactic radiosurgery (SRS).MethodA retrospective analysis of 104 SRS patients with kilovoltage image‐guided setup (Brainlab ExacTrac) data was performed. Each patient was imaged pre‐treatment, and at two time points during treatment (1st and 2nd mid‐treatment), and bony anatomy of the skull was used to establish setup error at each time point. The datasets included the translational and rotational setup error, as well as the time period between image acquisitions. After each image acquisition, the patient was repositioned using the calculated shift to correct the setup error. Only translational errors were corrected due to the absence of a 6D treatment table. Setup time and directional shift values were analyzed to determine correlation between shift magnitudes as well as time between acquisitions.ResultsThe average magnitude translation was 0.64 ± 0.59 mm, 0.79 ± 0.45 mm, and 0.65 ± 0.35 mm for the pre‐treatment, 1st mid‐treatment, and 2nd mid‐treatment imaging time points. The average time from pre‐treatment image acquisition to 1st mid‐treatment image acquisition was 7.98 ± 0.45 min, from 1st to 2nd mid‐treatment image was 4.87 ± 1.96 min. The greatest translation was 3.64 mm, occurring in the pre‐treatment image. No patient had a 1st or 2nd mid‐treatment image with greater than 2 mm magnitude shifts.ConclusionThere was no correlation between patient motion over time, in direction or magnitude, and duration of treatment. The imaging frequency could be reduced to decrease imaging dose and treatment time without significant changes in patient position.

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Section: Introductionmentioning

confidence: 99%

Monitoring frequency of intra‐fraction patient motion using the ExacTrac system for LINAC‐based SRS treatments

Lewis

Snyder

Kim

et al. 2018

J Applied Clin Med Phys

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“…According to repositioning accuracy of head mask systems (< 2 mm) [13,20], PTV consisted of the CTV plus a 2-mm safety margin. Corresponding to Zabel et al [35] reporting median total dose of 57.6 Gy, we prescribed median daily doses of 2.0 Gy up to median cumulative doses of 57.0 Gy at the reference point.…”

Section: Local Controlmentioning

confidence: 99%

Fractionated Stereotactic Radiotherapy of Glomus Jugulare Tumors

et al. 2007

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“…Repositioning accuracy was < 2 mm according to published data [16,21]. Patients underwent CT and MRI scans with 1-3 mm slice thickness for treatment planning.…”

Section: -D Treatment Planningmentioning

confidence: 99%