QUANTITATION IN POSITRON EMISSION COMPUTED-TOMOGRAPHY .4. EFFECT OF ACCIDENTAL COINCIDENCES
QUANTITATION IN POSITRON EMISSION COMPUTED-TOMOGRAPHY .4. EFFECT OF ACCIDENTAL COINCIDENCES
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DOI：
10.1097/00004728-198106000-00015
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发表时间：
1981-01-01
影响因子：
1.3
通讯作者：
KUHL, DE
中科院分区：
文献类型：
--
作者：
HOFFMAN, EJ;HUANG, SC;KUHL, DE
研究了正电子发射计算机断层扫描（ECT）中偶然符合（AC）及其补偿方法对定量的影响。给出了描述真符合或AC的物理因素的基本表达式，为对比这两种现象提供了一个框架。为了湮灭辐射的衰减或检测器效率的不均匀性而校正图像数据放大了由数据中AC的存在引起的误差。未能补偿AC造成高估的同位素浓度的测量从图像数据，在许多情况下，高估是显着的相对温和的百分比AC的数据。三种方法的补偿AC进行了评估，其准确性和对图像中的统计噪声的影响。如果在从图像数据中确定和减去AC时采用不适当的方法，则不均匀的检测器效率可能导致突出的图像伪影。通过从总符合数据中减去AC而在图像中产生的额外统计噪声证明了最小化AC率的可行性，尽管能够充分测量和补偿它们在数据中的存在。
Accidental coincidences (AC) and methods of compensation for AC were investigated in terms of their effect on quantitation in positron emission computed tomography (ECT). Formulations of basic expressions describing the physical factors, which cause true coincidences or AC, are presented to provide a framwork for contrasting the 2 phenomena. Correction of image data for attenuation of the annihilation radiation or nonuniformities in detector efficiency amplifies errors caused by the presence of AC in the data. Failure to compensate for AC caused overestimates in measurements of isotope concentrations from image data and that in many cases the overestimate was significant for relatively modest percentages of AC in the data. Three methods of compensation for AC were evaluated as to their accuracy and effect on statistical noise in images. Nonuniform detector efficiencies could cause prominent image artifacts if an inadequate method was employed in the determination and subtraction of AC from image data. The additional statistical noise produced in images by subtraction of AC from total coincidence data demonstrates the advisability of minimizing AC rates in spite of an ability to adequately measure and compensate for their presence in the data.