Clinic for Radiation Therapy, Pius Hospital, Oldenburg, Germany.
Strahlenther Onkol. 2012 Feb;188(2):185-90. doi: 10.1007/s00066-011-0030-y. Epub 2012 Jan 12.
The quality of megavoltage clinical portal images is impaired by physical and geometrical effects. This image blurring can be corrected by a fast numerical two-dimensional (2D) deconvolution algorithm implemented in the electronic portal image device. We present some clinical examples of deconvolved portal images and evaluate the clinical advantages achieved by the improved sharpness and contrast.
The principle of numerical 2D image deconvolution and the enhancement of sharpness and contrast thereby achieved are shortly explained. The key concept is the convolution kernel K(x,y), the mathematical equivalent of the smearing or blurring of a picture, and the computer-based elimination of this influence.
Enhancements of sharpness and contrast were observed in all clinical portal images investigated. The images of fine bone structures were restored. The identification of organ boundaries and anatomical landmarks was improved, thereby permitting a more accurate comparison with the x-ray simulator radiographs. The visibility of prostate gold markers is also shown to be enhanced by deconvolution.
The blurring effects of clinical portal images were eliminated by a numerical deconvolution algorithm that leads to better image sharpness and contrast. The fast algorithm permits the image blurring correction to be performed in real time, so that patient positioning verification with increased accuracy can be achieved in clinical practice.
兆伏级临床射野影像的质量因物理和几何效应而受损。这种图像模糊可以通过电子射野影像装置中实现的快速二维（2D）数值反卷积算法来纠正。我们呈现了一些经反卷积后的射野影像的临床实例，并评估了通过提高清晰度和对比度所获得的临床优势。
简要解释了数值二维图像反卷积的原理以及由此实现的清晰度和对比度的增强。关键概念是卷积核 K(x,y)，它是图像模糊或失真的数学等价物，通过计算机消除这种影响。
所有研究的临床射野影像的清晰度和对比度都得到了增强。精细骨结构的图像得到了恢复。器官边界和解剖标志的识别得到了改善，从而可以更准确地与射线模拟器射线照片进行比较。反卷积还显示出前列腺金标记的可见度得到了增强。
通过数值反卷积算法消除了临床射野影像的模糊效应，从而提高了图像的清晰度和对比度。快速算法允许实时进行图像模糊校正，从而可以在临床实践中实现更精确的患者定位验证。
