An image quality comparison study between XVI and OBI CBCT systems
An image quality comparison study between XVI and OBI CBCT systems
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DOI：
10.1120/jacmp.v12i2.3435
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发表时间：
2011-01-01
影响因子：
2.1
通讯作者：
Palta, Jatinder R.
中科院分区：
文献类型：
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作者：
Kamath, Srijit;Song, William;Palta, Jatinder R.
这项研究的目的是评估和比较两种常用和商业可用的CBCT系统的图像质量特征：X射线体积成像仪和车载成像仪。使用常用的CATPHAN图像质量体模测量各种图像质量参数，即像素值稳定性和精度、噪声、对比度噪声比(CNR)、高对比度分辨率、低对比度分辨率和图像均匀度。对于XVI单元，我们评估了制造商提供的四种协议的图像质量作为mAs的函数。对于OBI单元，我们对全扇和半扇扫描模式进行了同样的处理，这两种模式分别与全蝴蝶结滤镜和半蝴蝶结滤镜一起使用。对于XVI，对于所有协议，感兴趣区域的平均像素值通常随着mAs的增加而减小，而对于OBI，它们相对稳定。噪声在XVI上略低，并且随着mAs的增加而降低，而CNR随着mAs的增加而增加。对于XVI和OBI，高对比度分辨率大致受限于重建图像的像素分辨率。在OBI图像上，在使用全风扇模式的高mAs设置下，对比度分别为1%和0.5%的磁盘分别可见多达6个和5个，而当使用中等分辨率重建时，在各种mAs设置的XVI图像上都看不到清晰的磁盘。总之，XVI和OBI的图像质量参数已被量化，并在不同mAs设置下与临床方案进行了比较。这些结果需要结合最近的一项研究来看待，该研究报告了两个系统的剂量-毫安关系，并发现OBI通常比XVI提供更高的成像剂量。((1))
The purpose of this study is to evaluate and compare image quality characteristics for two commonly used and commercially available CBCT systems: the X-ray Volumetric Imager and the On-Board Imager. A commonly used CATPHAN image quality phantom was used to measure various image quality parameters, namely, pixel value stability and accuracy, noise, contrast to noise ratio (CNR), high-contrast resolution, low contrast resolution and image uniformity. For the XVI unit, we evaluated the image quality for four manufacturer-supplied protocols as a function of mAs. For the OBI unit, we did the same for the full-fan and half-fan scanning modes, which were respectively used with the full bow-tie and half bow-tie filters. For XVI, the mean pixel values of regions of interest were found to generally decrease with increasing mAs for all protocols, while they were relatively stable with mAs for OBI. Noise was slightly lower on XVI and was seen to decrease with increasing mAs, while CNR increased with mAs for both systems. For XVI and OBI, the high-contrast resolution was approximately limited by the pixel resolution of the reconstructed image. On OBI images, up to 6 and 5 discs of 1% and 0.5% contrast, respectively, were visible for a high mAs setting using the full-fan mode, while none of the discs were clearly visible on the XVI images for various mAs settings when the medium resolution reconstruction was used. In conclusion, image quality parameters for XVI and OBI have been quantified and compared for clinical protocols under various mAs settings. These results need to be viewed in the context of a recent study that reported the dose-mAs relationship for the two systems and found that OBI generally delivered higher imaging doses than XVI.((1))