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. Met...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.展开更多
文摘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.
