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Inter-Observes and Inter-Modality Variation Comparison Between Two Image Guided System for Renal Metastasis - a Pilot Study

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W Leung

W Leung*, M Wong , S Cheung , W Lee , Ray Wong, Hollis Luk, Fransica, Tuen Mun Hospital, Hong Kong, Hong Kong M Chan, Maidstone Hospital , United Kingdom


SU-I-GPD-J-33 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: To compare the inter-observers and inter-modality variation of cone beam computer tomography (CBCT) and Clarity ultrasound (US) for renal metastasis with fiducial markers.

Methods: A renal metastasis case with three gold anchor fiducial markers implanted was seamed by US first followed by four-dimension (4D) CBCT in every fraction. Mid-ventilation phase in CBCT was used for final positioning and treatment. Seven observers retrospectively performed the image registration. Registration variations between observers of these two modalities were evaluated.

Results: The uncertainties in US were 0.8mm, 0.97mm and 1.36mm in X, Y and Z direction respectively while 0.91mm, 1.61mm and 0.88mm were found in CBCT.

Conclusion: Since the US probe scanned in vertical direction, the echo enhancement around the markers was attributed to larger uncertainty in Z direction compared to CBCT. In 4D CBCT, the cranial-caudal movement blurred and elongated the markers in Y direction and resulted in larger uncertainty than in US.

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