This study evaluates the image quality of the new Varian HyperSight CBCT imager compared to fan-beam CT and two existing CBCT systems. The HyperSight CBCT uses advanced hardware, including a large flat panel detector and improved reconstruction algorithms, to enhance image quality. The study assesses metal artifact reduction (MAR), extended field-of-view (eFoV), and CT number accuracy across various phantoms. The MAR reconstruction significantly reduced metal artifacts, improving structural similarity index measure (SSIM) and decreasing root-mean-squared error (RMSE) compared to iterative reconstruction without MAR. The HyperSight CBCT showed better geometrical accuracy in the eFoV than CT, but lower CT number accuracy outside the standard field-of-view (sFoV). The CT number variation between different phantom sizes was lower for the HyperSight CBCT compared to other CBCT systems, though not fully comparable to CT. The study also evaluated image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) using an abdominal phantom. The HyperSight CBCT demonstrated comparable image quality to CT, with slightly better SNR and CNR. The results indicate that the HyperSight CBCT offers improved image quality and reduced noise, making it suitable for advanced radiotherapy applications. The study highlights the potential of the HyperSight CBCT in enhancing adaptive radiotherapy workflows by providing accurate imaging and reducing the need for correction of anatomical structures. The findings suggest that the HyperSight CBCT could be integrated into clinical practice for improved dose calculation and treatment planning.This study evaluates the image quality of the new Varian HyperSight CBCT imager compared to fan-beam CT and two existing CBCT systems. The HyperSight CBCT uses advanced hardware, including a large flat panel detector and improved reconstruction algorithms, to enhance image quality. The study assesses metal artifact reduction (MAR), extended field-of-view (eFoV), and CT number accuracy across various phantoms. The MAR reconstruction significantly reduced metal artifacts, improving structural similarity index measure (SSIM) and decreasing root-mean-squared error (RMSE) compared to iterative reconstruction without MAR. The HyperSight CBCT showed better geometrical accuracy in the eFoV than CT, but lower CT number accuracy outside the standard field-of-view (sFoV). The CT number variation between different phantom sizes was lower for the HyperSight CBCT compared to other CBCT systems, though not fully comparable to CT. The study also evaluated image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) using an abdominal phantom. The HyperSight CBCT demonstrated comparable image quality to CT, with slightly better SNR and CNR. The results indicate that the HyperSight CBCT offers improved image quality and reduced noise, making it suitable for advanced radiotherapy applications. The study highlights the potential of the HyperSight CBCT in enhancing adaptive radiotherapy workflows by providing accurate imaging and reducing the need for correction of anatomical structures. The findings suggest that the HyperSight CBCT could be integrated into clinical practice for improved dose calculation and treatment planning.