The investigation on the location effect of external markers in respiratory-gated radiotherapy.
Abstract
PURPOSE:To investigate the effect of the marker placement on the correlation relationship
between the motions of external markers and the internal target under different breathing
patterns for several lung cancer patients. METHOD AND MATERIAL:To monitor and record
simultaneous motions of internal target and associated surrogate markers during respiratory
gated radiotherapy, an infrared camera system synchronized with a medical simulator
was installed in our institute. Multiple external markers were placed on the patients'
chest wall with proper geometrical arrangement in closely monitoring the motion of
skin near tumor. The motion signals of three breathing sessions (free breathing, breath-holding,
and free breathing after breath-holding) were recorded and the quality of correlation
between them was analyzed. For a single marker motion, its correlation with the internal
target was analyzed using cross-covariance function. For the multiple markers, their
correlation with the internal target was analyzed based on additive model. RESULT:Seven
patients undergoing radiotherapy with right upper or middle lobe lesions were enrolled
in this study. Statistic analysis based on the internal-external motion signals shows
that the effect of marker location on the quality of its correlation with the internal
target is varied from patient to patient. There was no specific marker location where
consistently demonstrated superior quality of correlation with the internal target
motion over three breathing sessions for all patients. As the composite surrogate
signal which was generated from the motions of multiple external markers was used
to correlate the internal target motion, significant improvement of the quality of
correlation was achieved. CONCLUSION:The correlation of external marker to the internal
target could be influenced by several factors such as patient population, marker locations,
and breathing patterns, considerably. The quality of correlation and predictability
to the internal target furnished by a single external marker is inferior to that of
the composite signal generated from multiple external markers. The use of composite
signal shows great potential in improving the predictability of internal target motion
and presents an effective way to track tumor more accurately.
Type
Journal articleSubject
HumansAdenocarcinoma
Carcinoma, Squamous Cell
Breast Neoplasms
Lung Neoplasms
Radiotherapy Planning, Computer-Assisted
Respiration
Movement
Aged
Middle Aged
Female
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https://hdl.handle.net/10161/19394Published Version (Please cite this version)
10.1120/jacmp.v9i2.2758Publication Info
Yin, Fang-Fang; Yan, Hui; Zhu, Guopei; Yang, James; Lu, Mei; Ajlouni, Munther; & Kim,
Jae Ho (2008). The investigation on the location effect of external markers in respiratory-gated
radiotherapy. Journal of applied clinical medical physics, 9(2). pp. 2758. 10.1120/jacmp.v9i2.2758. Retrieved from https://hdl.handle.net/10161/19394.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Fang-Fang Yin
Professor in Radiation Oncology
Stereotactic radiosurgery, Stereotactic body radiation therapy, treatment planning
optimization, knowledge guided radiation therapy, intensity-modulated radiation therapy,
image-guided radiation therapy, oncological imaging and informatics

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