Dopamine D2 receptor SPECT with 123I-IBZM: evaluation of collimator and post-filtering when using model-based compensation-a Monte Carlo study
Dopamine D2 receptor SPECT with 123I-IBZM: evaluation of collimator and post-filtering when using model-based compensation-a Monte Carlo study
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DOI：
10.1088/0031-9155/55/7/012
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发表时间：
2010-04-07
影响因子：
3.5
通讯作者：
Riklund, Katrine
中科院分区：
文献类型：
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作者：
Larsson, Anne;Mo, Susanna Jakobson;Riklund, Katrine
在I-123-IBZM脑spect中，主要关注的是纹状体相对于背景的活动摄取，使用感兴趣区域的半定量技术通常用于此目的。然而，由于低对比度和高噪声水平，测量吸收的不确定性可能是一个问题。与一般的SPECT一样，IBZM SPECT应该受益于包括基于模型补偿的重建方法，但重要的是要针对该技术优化图像采集。一个重要的因素是准直器的选择。在这项研究中，我们比较了四种不同的IBZM SPECT平行孔准直器的总体定量精度和测量摄取比作为图像噪声和不确定度的函数。准直器包括低能量高分辨率准直器（LEHR）、低能量通用准直器（LEGP）、扩展准直器（ELEGP）和中能量通用准直器（MEGP）。研究了截止频率分别为0.3、0.45和0.6 cm(-1)（功率因数8）的三种巴特沃斯后滤波器的效果。所有原始数据预测都是使用蒙特卡罗模拟生成的。在所研究的准直器中，对主光子最敏感的elep被证明是最适合实际噪声水平的准直器。巴特沃斯后滤波是有利的，截止频率0.45 cm（-1）是本研究的最佳折衷。
In I-123-IBZM brainSPECT, the main interest is the activity uptake in the striatum relative to the background, and semi-quantitative techniques using regions of interest are typically used for this purpose. Uncertainties in the measured uptakes can however be a problem due to low contrasts and high noise levels. Like SPECT in general, IBZM SPECT should benefit from reconstruction methods that include model-based compensation, but it is important that image acquisition is optimized for this technique. An important factor is the choice of collimator. In this study we compare four different parallel-hole collimators for IBZM SPECT regarding overall quantitative accuracy and measured uptake ratio as a function of image noise and uncertainty. The collimators are low-energy high-resolution (LEHR), low-energy general-purpose (LEGP), extended LEGP (ELEGP) and medium-energy general-purpose (MEGP). The effect of three Butterworth post-filters with cut-off frequencies of 0.3, 0.45 and 0.6 cm(-1) ( power factor 8) is also studied. All raw-data projections are produced using Monte Carlo simulations. Of the investigated collimators, the one that is most sensitive to the primary photons, ELEGP, proved to be the most optimal for realistic noise levels. Butterworth post-filtering is advantageous, and the cut-off frequency 0.45 cm(-1) was the best compromise in this study.