This study scanned the Catphan 503 phantoms to evaluate the uniformity, noise, low contrast resolution and spatial resolution of Linac-integrated kV-cone beam CT image with choosing different scanning preset parame-ters, and analyzed the image variations changed with the tube voltage, tube current, collimator type, gantry scan-ning range and reconstruction precision. The results showed that improving X-ray tube voltage and current, expen-ding the scanning gantry rotation range and reducing collimator size, increasing reconstruction precision and other imaging parameters were conducive to high quality cone beam CT images. As a result, patients suffered more addi-tional X-ray radiation and X-ray tube and detector components loss increased, simultaneously. Imaging scanning preset parameters should be reasonably chosen according to the patient's anatomy,which can guarantee the image quality and minimize patient radiation dose.%采用Catphan 503模体，选用不同的扫描预设条件成像，对加速器机载千伏级锥形束CT( kV-CBCT)图像的均匀性、噪声、低对比度分辨率和空间分辨率进行评估。结果表明提高X线球管管电压管电流、增大机架旋转扫描范围、减小准直器尺寸、提高重建精度等参数有利于获得高质量锥形束CT( CBCT)图像，但同时患者将多受额外的X射线辐射，也加大X线球管和探测器等元器件的损耗。因此，临床使用中应根据患者解剖条件合理选择成像参数，这样既能保证图像质量，又尽可能降低患者的辐射剂量。
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