Dataset Information

Automatic measurement of beam-positioning accuracy at off-isocenter positions.

ABSTRACT:

Purpose

This study performed an automatic measurement of the off-axis beam-positioning accuracy at a single isocenter via the TrueBeam Developer mode and evaluated the beam-positioning accuracy considering the effect of couch rotational errors.

Methods

TrueBeam STx and the Winston-Lutz test-dedicated phantom, with a 3 mm diameter steel ball, were used in this study. The phantom was placed on the treatment couch, and the Winston-Lutz test was performed at the isocenter for four gantry angles (0°, 90°, 180°, and 270°) using an electronic portal imaging device. The phantom offset positions were at distances of 0, 25, 50, 75, and 100 mm from the isocenter along the superior-inferior, anterior-posterior, and left-right directions. Seventeen patterns of multileaf collimator-shaped square fields of 10 × 10 mm² were created at the isocenter and off-axis positions for each gantry angle. The beam-positioning accuracy was evaluated with couch rotation along the yaw-axis (0°, ± 0.5°, and ± 1.0°).

Results

The mean beam-positioning errors at the isocenter and off-isocenter distances (from the isocenter to ±100 mm) were 0.46-0.60, 0.44-0.91, and 0.42-1.11 mm for the couch angles of 0°, ±0.5°, and ±1°, respectively. The beam-positioning errors increased as the distance from the isocenter and couch rotation increased.

Conclusion

These findings suggest that the beam-positioning accuracy at the isocenter and off-isocenter positions can be evaluated quickly and automatically using the TrueBeam Developer mode. The proposed procedure is expected to contribute to an efficient evaluation of the beam-positioning accuracy at off-isocenter positions.

SUBMITTER: Ono T

PROVIDER: S-EPMC10018661 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature

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Publications

Automatic measurement of beam-positioning accuracy at off-isocenter positions.

Ono Tomohiro T Kido Takahisa T Nakamura Mitsuhiro M Iramina Hiraku H Kakino Ryo R Mizowaki Takashi T

Journal of applied clinical medical physics 20221124 3

<h4>Purpose</h4>This study performed an automatic measurement of the off-axis beam-positioning accuracy at a single isocenter via the TrueBeam Developer mode and evaluated the beam-positioning accuracy considering the effect of couch rotational errors.<h4>Methods</h4>TrueBeam STx and the Winston-Lutz test-dedicated phantom, with a 3 mm diameter steel ball, were used in this study. The phantom was placed on the treatment couch, and the Winston-Lutz test was performed at the isocenter for four gan ...[more]

PMID: 36420973

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Dataset Information

Automatic measurement of beam-positioning accuracy at off-isocenter positions.

Purpose

Methods

Results

Conclusion

Publications

Automatic measurement of beam-positioning accuracy at off-isocenter positions.

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