TY - JOUR
T1 - Monitoring frequency of intra-fraction patient motion using the ExacTrac system for LINAC-based SRS treatments
AU - Lewis, Benjamin C.
AU - Snyder, William J.
AU - Kim, Siyong
AU - Kim, Taeho
N1 - Publisher Copyright:
© 2018 Virginia Commonwealth University. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.
PY - 2018/5
Y1 - 2018/5
N2 - Purpose: The aim of this study was to investigate the intra-fractional patient motion using the ExacTrac system in LINAC-based stereotactic radiosurgery (SRS). Method: A retrospective analysis of 104 SRS patients with kilovoltage image-guided setup (Brainlab ExacTrac) data was performed. Each patient was imaged pre-treatment, and at two time points during treatment (1st and 2nd mid-treatment), and bony anatomy of the skull was used to establish setup error at each time point. The datasets included the translational and rotational setup error, as well as the time period between image acquisitions. After each image acquisition, the patient was repositioned using the calculated shift to correct the setup error. Only translational errors were corrected due to the absence of a 6D treatment table. Setup time and directional shift values were analyzed to determine correlation between shift magnitudes as well as time between acquisitions. Results: The average magnitude translation was 0.64 ± 0.59 mm, 0.79 ± 0.45 mm, and 0.65 ± 0.35 mm for the pre-treatment, 1st mid-treatment, and 2nd mid-treatment imaging time points. The average time from pre-treatment image acquisition to 1st mid-treatment image acquisition was 7.98 ± 0.45 min, from 1st to 2nd mid-treatment image was 4.87 ± 1.96 min. The greatest translation was 3.64 mm, occurring in the pre-treatment image. No patient had a 1st or 2nd mid-treatment image with greater than 2 mm magnitude shifts. Conclusion: There was no correlation between patient motion over time, in direction or magnitude, and duration of treatment. The imaging frequency could be reduced to decrease imaging dose and treatment time without significant changes in patient position.
AB - Purpose: The aim of this study was to investigate the intra-fractional patient motion using the ExacTrac system in LINAC-based stereotactic radiosurgery (SRS). Method: A retrospective analysis of 104 SRS patients with kilovoltage image-guided setup (Brainlab ExacTrac) data was performed. Each patient was imaged pre-treatment, and at two time points during treatment (1st and 2nd mid-treatment), and bony anatomy of the skull was used to establish setup error at each time point. The datasets included the translational and rotational setup error, as well as the time period between image acquisitions. After each image acquisition, the patient was repositioned using the calculated shift to correct the setup error. Only translational errors were corrected due to the absence of a 6D treatment table. Setup time and directional shift values were analyzed to determine correlation between shift magnitudes as well as time between acquisitions. Results: The average magnitude translation was 0.64 ± 0.59 mm, 0.79 ± 0.45 mm, and 0.65 ± 0.35 mm for the pre-treatment, 1st mid-treatment, and 2nd mid-treatment imaging time points. The average time from pre-treatment image acquisition to 1st mid-treatment image acquisition was 7.98 ± 0.45 min, from 1st to 2nd mid-treatment image was 4.87 ± 1.96 min. The greatest translation was 3.64 mm, occurring in the pre-treatment image. No patient had a 1st or 2nd mid-treatment image with greater than 2 mm magnitude shifts. Conclusion: There was no correlation between patient motion over time, in direction or magnitude, and duration of treatment. The imaging frequency could be reduced to decrease imaging dose and treatment time without significant changes in patient position.
KW - SRS
KW - brainlab ExacTrac
KW - intra-fraction imaging
KW - stereotactic radiosurgery
UR - http://www.scopus.com/inward/record.url?scp=85044435343&partnerID=8YFLogxK
U2 - 10.1002/acm2.12279
DO - 10.1002/acm2.12279
M3 - Article
C2 - 29577592
AN - SCOPUS:85044435343
SN - 1526-9914
VL - 19
SP - 58
EP - 63
JO - Journal of applied clinical medical physics
JF - Journal of applied clinical medical physics
IS - 3
ER -