Guvenis A, Koc A
Institute of Biomedical Engineering, Bogazici University, Kandilli Kampus, Cengelkoy, Istanbul 34684, Turkey
Institute of Biomedical Engineering, Bogazici University, Kandilli Kampus, Cengelkoy, Istanbul 34684, Turkey University of Kirklareli, Vocational College of Health Services, Kirklareli, Turkey.
Radiat Prot Dosimetry. 2015 Jul;165(1-4):495-8. doi: 10.1093/rpd/ncv110. Epub 2015 Apr 1.
Positron emission tomography (PET) imaging has been proven to be useful in radiotherapy planning for the determination of the metabolically active regions of tumours. Delineation of tumours, however, is a difficult task in part due to high noise levels and the partial volume effects originating mainly from the low camera resolution. The goal of this work is to study the effect of blind deconvolution on tumour volume estimation accuracy for different computer-aided contouring methods. The blind deconvolution estimates the point spread function (PSF) of the imaging system in an iterative manner in a way that the likelihood of the given image being the convolution output is maximised. In this way, the PSF of the imaging system does not need to be known. Data were obtained from a NEMA NU-2 IQ-based phantom with a GE DSTE-16 PET/CT scanner. The artificial tumour diameters were 13, 17, 22, 28 and 37 mm with a target/background ratio of 4:1. The tumours were delineated before and after blind deconvolution. Student's two-tailed paired t-test showed a significant decrease in volume estimation error (p < 0.001) when blind deconvolution was used in conjunction with computer-aided delineation methods. A manual delineation confirmation demonstrated an improvement from 26 to 16 % for the artificial tumour of size 37 mm while an improvement from 57 to 15 % was noted for the small tumour of 13 mm. Therefore, it can be concluded that blind deconvolution of reconstructed PET images may be used to increase tumour delineation accuracy.
正电子发射断层扫描（PET）成像已被证明在放射治疗计划中有助于确定肿瘤的代谢活跃区域。然而，肿瘤的勾画是一项艰巨的任务，部分原因是噪声水平高以及主要源于相机分辨率低的部分容积效应。这项工作的目标是研究盲反卷积对不同计算机辅助轮廓勾画方法的肿瘤体积估计准确性的影响。盲反卷积以迭代方式估计成像系统的点扩散函数（PSF），使得给定图像作为卷积输出的可能性最大化。通过这种方式，无需知道成像系统的PSF。数据来自使用GE DSTE - 16 PET/CT扫描仪的基于NEMA NU - 2 IQ的体模。人工肿瘤直径为13、17、22、28和37毫米，靶/本底比为4:1。在盲反卷积前后对肿瘤进行勾画。当盲反卷积与计算机辅助勾画方法结合使用时，学生双尾配对t检验显示体积估计误差显著降低（p < 0.001）。手动勾画确认显示，对于37毫米大小的人工肿瘤，改进从26%提高到16%，而对于13毫米的小肿瘤，改进从57%提高到15%。因此，可以得出结论，重建PET图像的盲反卷积可用于提高肿瘤勾画的准确性。
