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Home > 학회활동 > 국제학술지 |
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작성일 : 11-10-10 18:37
| 저 자 |
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Jai-Woong Yoon et al |
| 제 목 |
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Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking |
| 학회지명 |
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Medical Physics |
| 권 호 |
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38 (7) |
| 페이지 |
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3924-3931 |
| 년,월 |
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2011-10-10 |
| 링 크 |
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| Abstract |
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Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensitymodulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to
balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a
dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion
perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average
algorithm compared with real-time tracking and no compensation beam delivery is described.
Methods: The properties of the moving average algorithm were measured and compared with those
of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and
perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was
investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each
motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy,
and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding
window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a c-test with a 3%=3 mm criterion.
Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%–100%
for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7–1.1 mm for real-time
tracking, and 3.7–7.2 mm for no compensation. The percentage of dosimetric points failing the
c-test ranged from 4 to 30% for moving average tracking, 0%–23% for real-time tracking, and
10%–47% for no compensation.
Conclusions: The delivery efficiency of moving average tracking was up to four times higher than that
of real-time tracking and approached the efficiency of no compensation for all cases. The geometric accuracy and dosimetric accuracy of the moving average algorithm was between real-time tracking and no
compensation, approximately half the percentage of dosimetric points failing the c-test compared with no
compensation. |
 2011_윤제웅_Med.Phys.PDF (1.6M) [595] DATE : 2011-10-10 18:37:45 |
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