Improved quantification in 123I cardiac SPECT imaging with deconvolution of septal penetration
Improved quantification in 123I cardiac SPECT imaging with deconvolution of septal penetration
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DOI：
10.1097/00006231-200607000-00002
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发表时间：
2006-07-01
影响因子：
1.5
通讯作者：
Carrio, Ignasi
中科院分区：
文献类型：
--
作者：
Chen, Ji;Garcia, Ernest V.;Carrio, Ignasi
目的I-123正逐渐成为心脏显像的重要核素。与I-123成像相关的多个低丰度高能光子可导致准直器中的间隔穿透，并降低I-123心脏摄取的定量。本研究提出了一种方法，用于去卷积的间隔穿透（DSP），以提高定量I-123心脏单光子发射计算机断层扫描（SPECT）。方法距离依赖的点扩散函数测量低能量高分辨率准直器上的双头SPECT系统。测量的点扩散函数分别用于准直器响应的二维（2-D）和三维（3-D）模型。2-D DSP和3-D DSP，然后开发和实现使用迭代重建。设计了具有内部校准源的心脏躯干体模，其具有各种心脏校准比（HCR），模拟患者摄取的不同水平。使用I-123心脏SPECT的优化采集和处理参数进行体模的SPECT采集。使用平面投影和断层重建计算HCR。结果SPECT显像的HCR比平面显像的HCR准确。使用滤波反投影的SPECT回归线斜率在统计学上显著高于平面成像（0.2118 +/- 0.0297 vs. 0.0819 +/- 0.0070，P=0.0001）。2-D DSP和3-D DSP产生接近真实HCR的相似HCR。2-D DSP和3-D DSP的回归线斜率分别为0.9203 +/- 0.0523和0.9101 +/- 0.0304。结论DSP能显著提高I-123心肌SPECT显像的定量准确性。2-D DSP以其较少的计算负担显示出在临床实践中实施的希望，以便允许使用广泛可用的低能量、高分辨率准直器进行定量I-123心脏SPECT成像。
Objectives I-123 is becoming an important radionuclide for cardiac imaging. Multiple, low-abundance, high-energy photons associated with I-123 imaging can cause septal penetration in the collimators and degrade quantification of the I-123 cardiac uptake. This study presents a method for the deconvolution of septal penetration (DSP) for improving quantification in I-123 cardiac single photon emission computed tomography (SPECT).Methods Distance-dependent point spread functions were measured for low-energy high-resolution collimators on a dual-head SPECT system. The measured point spread functions were used in two-dimensional (2-D) and three-dimensional (3-D) models of the collimator response, respectively. 2-D DSP and 3-D DSP were then developed and implemented using iterative reconstruction. A cardiac torso phantom with an internal calibration source was designed with various heart-to-calibration ratios (HCRs) simulating different levels of a patient's uptake. SPECT acquisitions of the phantom were performed using optimized acquisition and processing parameters for I-123 cardiac SPECT. HCRs were calculated using planar projection and tomographic reconstructions. The paired Mest and regression analysis were used to compare the HCRs given by different calculation methods.Results SPECT produced more accurate HCRs than planar imaging. The slopes of the regression lines for SPECT using filtered back-projection were statistically significantly higher than those for planar imaging (0.2118 +/- 0.0297 vs. 0.0819 +/- 0.0070, P=0.0001). 2-D DSP and 3-D DSP yielded similar HCRs that were close to the true HCR. The slopes of the regression lines for 2-D DSP and 3-D DSP were 0.9203 +/- 0.0523 and 0.9101 +/- 0.0304, respectively. The DSP HCRs were significantly more accurate than those calculated without DSP (P < 0.0001).Conclusion DSP significantly improves quantification in I-123 cardiac SPECT imaging. 2-D DSP with its less computational burden shows promise for implementation in clinical practice so as to allow the use of the widely available low-energy, high-resolution collimators for quantitative I-123 cardiac SPECT imaging.