TY - JOUR
T1 - Correlation between internal fiducial tumor motion and external marker motion for liver tumors imaged with 4D-CT
AU - Beddar, A. Sam
AU - Kainz, Kristofer
AU - Briere, Tina Marie
AU - Tsunashima, Yoshikazu
AU - Pan, Tinsu
AU - Prado, Karl
AU - Mohan, Radhe
AU - Gillin, Michael
AU - Krishnan, Sunil
PY - 2007/2/1
Y1 - 2007/2/1
N2 - Purpose: We investigated the correlation between the motions of an external marker and internal fiducials implanted in the liver for 8 patients undergoing respiratory-based computed tomography (four-dimensional CT [4D-CT]) procedures. Methods and Materials: The internal fiducials were gold seeds, 3 mm in length and 1.2 mm in diameter. Four patients each had one implanted fiducial, and the other four had three implanted fiducials. The external marker was a plastic box, which is part of the Real-Time Position Management System (RPM) used to track the patient's respiration. Each patient received a standard helical CT scan followed by a time-correlated CT-image acquisition (4D-CT). The 4D-CT images were reconstructed in 10 separate phases covering the entire respiratory cycle. Results: The internal fiducial motion is predominant in the superior-inferior direction, with a range of 7.5-17.5 mm. The correlation between external respiration and internal fiducial motion is best during expiration. For 2 patients with their three fiducials separated by a maximum of 3.2 cm, the motions of the fiducials were well correlated, whereas for 2 patients with more widely spaced fiducials, there was less correlation. Conclusions: In general, there is a good correlation between internal fiducial motion imaged by 4D-CT and external marker motion. We have demonstrated that gating may be best performed at the end of the respiratory cycle. Special attention should be paid to gating for patients whose fiducials do not move in synchrony, because targeting on the correct respiratory amplitude alone would not guarantee that the entire tumor volume is within the treatment field.
AB - Purpose: We investigated the correlation between the motions of an external marker and internal fiducials implanted in the liver for 8 patients undergoing respiratory-based computed tomography (four-dimensional CT [4D-CT]) procedures. Methods and Materials: The internal fiducials were gold seeds, 3 mm in length and 1.2 mm in diameter. Four patients each had one implanted fiducial, and the other four had three implanted fiducials. The external marker was a plastic box, which is part of the Real-Time Position Management System (RPM) used to track the patient's respiration. Each patient received a standard helical CT scan followed by a time-correlated CT-image acquisition (4D-CT). The 4D-CT images were reconstructed in 10 separate phases covering the entire respiratory cycle. Results: The internal fiducial motion is predominant in the superior-inferior direction, with a range of 7.5-17.5 mm. The correlation between external respiration and internal fiducial motion is best during expiration. For 2 patients with their three fiducials separated by a maximum of 3.2 cm, the motions of the fiducials were well correlated, whereas for 2 patients with more widely spaced fiducials, there was less correlation. Conclusions: In general, there is a good correlation between internal fiducial motion imaged by 4D-CT and external marker motion. We have demonstrated that gating may be best performed at the end of the respiratory cycle. Special attention should be paid to gating for patients whose fiducials do not move in synchrony, because targeting on the correct respiratory amplitude alone would not guarantee that the entire tumor volume is within the treatment field.
KW - 4D-CT imaging
KW - Hepatobiliary Cancer
KW - Internal fiducials
KW - Respiratory gating
KW - Tumor motion
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U2 - 10.1016/j.ijrobp.2006.10.007
DO - 10.1016/j.ijrobp.2006.10.007
M3 - Article
C2 - 17236980
AN - SCOPUS:33846245486
SN - 0360-3016
VL - 67
SP - 630
EP - 638
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -