TITLE:
A Technical Note: Inter-Observer and Inter-Modality Variability of Cone-Beam Computed Tomography (CBCT) and Ultrasound (US) in Stereotactic Body Radiotherapy for Kidney Cancer
AUTHORS:
Ronnie W. K. Leung, Matthew Y. P. Wong, Venus W. Y. Lee, Steven K. T. Cheung, Aray K. L. Wong, Hollis S. L. Luk, Francesca K. L. Ng, Gilbert M. L. Law, Frankle K. H. Lee, W. H. Mui, Dennis Y. K. Ngar
KEYWORDS:
Inter-Observer, Inter-Modality, Variability, CBCT, US, Kidney SBRT
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.6 No.4,
November
3,
2017
ABSTRACT: Introduction: To
investigate the inter-observer and inter-modality variabilities of two imaging
guided equipments—cone-beam
computed tomography (CBCT) and ultrasound (US) in kidney stereotactic body
radiotherapy. Methods: A renal metastasis case implanted with three gold anchor fiducial
markers was firstly scanned by US to acquire a 3-dimension US image and
followed by 4-dimension CBCT in every fraction. Seven observers retrospectively
registered the pre-treatment images with the
corresponding reference images based on
the gold markers. Registration uncertainty of the observers between two imaging modalities was evaluated. Results: The
uncertainties over whole treatment course in CBCT were 0.88 mm, 1.94 mm and
0.86 mm in lateral, longitudinal and vertical directions respectively; while
0.8 mm, 0.97 mm and 1.36 mm were found in US. Conclusion: The
greatest uncertainty was found in longitudinal direction in CBCT due to the
fact that the respiration motion is the most rigorous in cranial-caudal
direction. In US, since the probe was hold almost in upright position, the
strong echo in vertical direction was attributed to the greatest uncertainty
for such direction.