机载CBCT扫描协议对图像质量的影响分析

目的:分析不同扫描协议对CBCT图像的质量影响，为临床扫描协议使用提供参考。方法:使用瓦里安VitalBeam加速器机载CBCT扫描Catphan 604模体，分析扫描协议中管电压、管电流、脉冲时间、机架速率、帧速率、滤线器对图像的影响。结果:头部扫描协议下图像HU值受管电压、帧速率影响明显，体部扫描协议图像HU值受管电压、管电流影响明显。管电压、管电流增加可改善图像均匀性同时降低图像噪声。高对比度分辨力受参数变化影响不明显，增加管电压、管电流或降低机架速度可明显提高图像低对比度分辨力。结论:管电压、管电流、帧速率等参数对CBCT图像影响不可忽略，应根据临床需要设置合理的扫描协议。

Analysis of the influence of airborne CBCT scanning protocol on image quality

Objective:To analyze the impact of different scanning protocols on the quality of CBCT images.Methods:The Catphan 604 phantom was scanned with the onboard CBCT of the varian VitalBeam accelerator to analyze the influence of the voltage,current,pulse length,gantry speed,frame rate,and fan type on the image in the scanning protocol.Results:The image HU value under the head scan protocol is significantly affected by the management voltage and frame rate,and the body scan protocol image HU value is significantly affected by the management voltage and current.The increase of voltage and current can improve image uniformity and reduce image noise.High-contrast resolution is not significantly affected by parameter changes.Increasing voltage,current or reducing gantry speed can significantly improve image low-contrast resolution.Conclusion:The influence of voltage,current,frame rate and other parameters on CBCT images cannot be ignored,and a reasonable scanning protocol should be set according to clinical needs.