TY - JOUR
T1 - On-Line Target Position Localization in the Presence of Respiration
T2 - A Comparison of two Methods
AU - Hugo, Geoffrey D.
AU - Liang, Jian
AU - Campbell, Jonathan
AU - Yan, Di
N1 - Funding Information:
Supported in part by National Cancer Institute Grant R01 CA091020.
PY - 2007/12/1
Y1 - 2007/12/1
N2 - Purpose: To compare two "four-dimensional" methods for image-guided target localization in the presence of respiration. Methods and Materials: Four-dimensional image guidance was performed with two methods. A respiration-correlated computed tomography (RCCT) was acquired on a CT simulator, and an average CT (AVG-CT) image was generated from the RCCT. A respiration-correlated cone-beam CT (RC-CBCT) and a free-breathing cone-beam CT (FB-CBCT) were acquired. The "RCCT method" consisted of calculating the mean target position on both the RCCT and RC-CBCT, registering the RCCT to the RC-CBCT, and determining the shift in the mean target position from the planned mean position. The "AVG-CT method" consisted of registering the AVG-CT to the FB-CBCT. The ability of each to measure the shift in the mean target position was compared, both in a respiratory phantom and in 8 patients. Results: In phantom, the RCCT and AVG-CT methods were able to measure the true mean target position to within 0.15 cm and 0.10 cm, respectively. In the patient study, the mean error between the methods was 0.13 cm (left-right), 0.14 cm (anterior-posterior), and 0.10 cm (cranio-caudal). The error was not observed to vary with tumor position or magnitude of tumor motion. Conclusions: Respiration may impact the on-line image guidance process. The RCCT method enables localization of the mean tumor position and measurement of changes in the motion pattern, whereas the AVG-CT method is simple, fast, and easily implemented. We found the methods to be nearly equivalent in detecting shifts in the mean tumor position.
AB - Purpose: To compare two "four-dimensional" methods for image-guided target localization in the presence of respiration. Methods and Materials: Four-dimensional image guidance was performed with two methods. A respiration-correlated computed tomography (RCCT) was acquired on a CT simulator, and an average CT (AVG-CT) image was generated from the RCCT. A respiration-correlated cone-beam CT (RC-CBCT) and a free-breathing cone-beam CT (FB-CBCT) were acquired. The "RCCT method" consisted of calculating the mean target position on both the RCCT and RC-CBCT, registering the RCCT to the RC-CBCT, and determining the shift in the mean target position from the planned mean position. The "AVG-CT method" consisted of registering the AVG-CT to the FB-CBCT. The ability of each to measure the shift in the mean target position was compared, both in a respiratory phantom and in 8 patients. Results: In phantom, the RCCT and AVG-CT methods were able to measure the true mean target position to within 0.15 cm and 0.10 cm, respectively. In the patient study, the mean error between the methods was 0.13 cm (left-right), 0.14 cm (anterior-posterior), and 0.10 cm (cranio-caudal). The error was not observed to vary with tumor position or magnitude of tumor motion. Conclusions: Respiration may impact the on-line image guidance process. The RCCT method enables localization of the mean tumor position and measurement of changes in the motion pattern, whereas the AVG-CT method is simple, fast, and easily implemented. We found the methods to be nearly equivalent in detecting shifts in the mean tumor position.
KW - Cone-beam CT
KW - Image guidance
KW - Lung cancer
KW - Respiratory motion
UR - http://www.scopus.com/inward/record.url?scp=36148932560&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2007.08.023
DO - 10.1016/j.ijrobp.2007.08.023
M3 - Article
C2 - 18029112
AN - SCOPUS:36148932560
SN - 0360-3016
VL - 69
SP - 1634
EP - 1641
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 5
ER -