Kennedy John A, Israel Ora, Frenkel Alex, Bar-Shalom Rachel, Azhari Haim
Faculty of Biomedical Engineering, Technion Israel Institute of Technology, 32000, Haifa, Israel.
Med Biol Eng Comput. 2007 Jun;45(6):553-62. doi: 10.1007/s11517-007-0188-8. Epub 2007 May 23.
CT beam hardening artifacts near metal hip implants may erroneously enhance or diminish radiotracer uptake following CT attenuation correction (AC) of PET images. An artifact reduction algorithm (ARA) was developed to reduce metal artifacts in CT-based AC-PET. The algorithm employed a Bayes classifier to identify beam-hardening artifacts, followed by a partial correction of the attenuation map. ARA was implemented on phantom and patient 18F-FDG studies using a clinical PET/CT scanner. In phantom studies ARA successfully removed two artifacts of erroneously elevated uptake near a stainless steel hip prosthesis which were depicted in the standard CT-AC PET. ARA has also identified two targets absent on the scanner PET images. Target-to-background ratios were 1.5-3 times higher for ARA-PET than scanner images. In a patient study, metal artifacts were of lower intensity in ARA-PET as compared to standard images. Potentially, ARA may improve detectability of small lesions located near metal hip implants.
金属髋关节植入物附近的CT束硬化伪影可能会在PET图像的CT衰减校正（AC）后错误地增强或减弱放射性示踪剂摄取。开发了一种伪影减少算法（ARA）以减少基于CT的AC-PET中的金属伪影。该算法采用贝叶斯分类器来识别束硬化伪影，随后对衰减图进行部分校正。使用临床PET/CT扫描仪在体模和患者18F-FDG研究中实施了ARA。在体模研究中，ARA成功消除了标准CT-AC PET中描绘的不锈钢髋关节假体附近摄取错误升高的两个伪影。ARA还识别出扫描仪PET图像上不存在的两个目标。ARA-PET的靶本底比是扫描仪图像的1.5至3倍。在一项患者研究中，与标准图像相比，ARA-PET中的金属伪影强度较低。ARA可能会提高位于金属髋关节植入物附近的小病变的可检测性。
