Wang Zhexin, Liu Hui, Cheng Li, Lyu Zhenlei, Gao Lilei, Jiang Nianming, He Zuoxiang, Liu Yaqiang
Department of Engineering Physics, Tsinghua University, Beijing, China.
Institute for Precision Medicine, Tsinghua University, Beijing, China.
J Med Phys. 2024 Jan-Mar;49(1):110-119. doi: 10.4103/jmp.jmp_127_23. Epub 2024 Mar 30.
We have developed a bone-dedicated collimator with higher sensitivity but slightly degraded resolution on single-photon emission computed tomography (SPECT) for planar bone scintigraphy, compared with conventional low-energy high-resolution collimator. In this work, we investigated the feasibility of using the blind deconvolution algorithm to improve the resolution of planar images on bone scintigraphy.
Monte Carlo simulation was performed with the NCAT phantom for modeling bone scintigraphy on the clinical dual-head SPECT scanner (Imagine NET 632, Beijing Novel Medical Equipment Ltd.) equipped with the bone-dedicated collimator. Maximum likelihood estimation method was used for the blind deconvolution algorithm. The initial estimation of point spread function (PSF) and iteration number for the method were determined by comparing the deblurred images obtained from different input parameters. We simulated different tumors in five different locations and with five different diameters to evaluate the robustness of the initial inputs. Furthermore, we performed chest phantom studies on the clinical SPECT scanner. The quantified increased contrast ratio (CR) between the tumor and the background was evaluated.
The 2 mm PSF kernel and 10 iterations provided a practical and robust deblurred image on our system. Those two inputs can generate robust deblurred images in terms of the tumor location and size with an average increased CR of 21.6%. The phantom studies also demonstrated the ability of blind deconvolution, using those two inputs, with increased CRs of 17%, 17%, 22%, 20%, and 13% for lesions with diameters of 1 cm, 2 cm, 3 cm, 4 cm, and 5 cm, respectively.
It is feasible to use the blind deconvolution algorithm to deblur the planar images for SPECT bone scintigraphy. The appropriate values of the PSF kernel and the iteration number for the blind deconvolution can be determined using simulation studies.
我们开发了一种用于平面骨闪烁显像的骨专用准直器，与传统的低能高分辨率准直器相比，其在单光子发射计算机断层扫描（SPECT）上具有更高的灵敏度，但分辨率略有下降。在这项工作中，我们研究了使用盲反卷积算法提高骨闪烁显像平面图像分辨率的可行性。
使用NCAT体模在配备骨专用准直器的临床双头SPECT扫描仪（北京新华医疗设备有限公司的Imagine NET 632）上进行骨闪烁显像建模的蒙特卡罗模拟。盲反卷积算法采用最大似然估计法。通过比较不同输入参数得到的去模糊图像，确定该方法的点扩散函数（PSF）初始估计值和迭代次数。我们在五个不同位置模拟了不同直径的五种不同肿瘤，以评估初始输入的稳健性。此外，我们在临床SPECT扫描仪上进行了胸部体模研究。评估了肿瘤与背景之间量化的对比度增加率（CR）。
2mm的PSF核和10次迭代在我们的系统上提供了实用且稳健的去模糊图像。这两个输入在肿瘤位置和大小方面能够生成稳健的去模糊图像，平均对比度增加率为21.6%。体模研究还证明了使用这两个输入的盲反卷积能力，对于直径为1cm、2cm、3cm、4cm和5cm的病变，对比度增加率分别为17%、17%、22%、20%和13%。
使用盲反卷积算法对SPECT骨闪烁显像的平面图像进行去模糊是可行的。可以通过模拟研究确定盲反卷积的PSF核和迭代次数的合适值。
