18F-FDG-PET检查中注射误差的SUV校正

SUV correction for injection errors in FDG-PET examination.

作者信息

Miyashita Kouichi, Takahashi Nobukazu, Oka Takashi, Asakawa Shinobu, Lee Jin, Shizukuishi Kazuya, Inoue Tomio

机构信息

Department of Radiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.

出版信息

Ann Nucl Med. 2007 Dec;21(10):607-13. doi: 10.1007/s12149-007-0068-1. Epub 2007 Dec 25.

DOI:10.1007/s12149-007-0068-1

PMID:18092139

Abstract

OBJECTIVE

Many studies have documented the clinical usefulness of standardized uptake values (SUV) for diagnosis. However, in the event of injection error, accurate measurements cannot be obtained if the radioactivity of fluorodeoxyglucose (FDG) leakage is not subtracted from the administered dosage. Here, a correction formula for radioactivity estimation that takes into account the radioactivity of FDG leakage was derived on the basis of a phantom experiment. Furthermore, to determine whether SUV could be accurately calculated by the correction formula, we performed a volunteer study.

METHODS

Images were displayed by altering the conversion constant from 1.0, 0.1 to 0.01, and the range of correctable counts was verified on the basis of image inversion. To estimate the radioactivity of FDG leakage by imaging, the count of the leakage was measured, converted into a radioactivity concentration using a cross-calibration factor (CCF), and multiplied by volume, as measured by imaging. Three factors that markedly affect count, i.e., count rate performance, partial volume effect and crosstalk, were assessed in phantom studies in order to derive a correction formula. In addition, to clarify the accuracy of the correction formula, we attached to the right elbow.

RESULTS

With a conversion constant of 0.1, there was no image inversion at <or=1.565 MBq/ml. At concentrations below this, the average detection rate was 90%. This suggests that count rate performance can be corrected at <or=1.0 MBq/ml. Crosstalk investigations clarified that the effects of adjacent radioactivity concentrations on FDG leakage were not marked. On the basis of investigations on partial volume effect and count rate performance, the following formulas were derived: For leakages of >or=28 mm Leakage radioactivity (MBq)=positron emission tomography (PET) radioactivity (MBq)x0.9. For leakages of >or=15 mm but <28 mm Leakage radioactivity (MBq)=PET radioactivity (MBq)x0.9x(0.0517xleakage size (mm)-0.4029). In a volunteer study with 10 MBq leakage, SUV recalculated using the formula achieved 99.97% correction, whereas with 100 MBq leakage, SUV achieved 67.5% resulting in poor correction.

CONCLUSIONS

The present correction technique can accurately calculate SUV and could be useful for the clinical diagnosis of malignant tumors.

摘要

目的

许多研究已证明标准化摄取值（SUV）在诊断中的临床实用性。然而，在发生注射错误的情况下，如果不从给药剂量中减去氟脱氧葡萄糖（FDG）渗漏的放射性，则无法获得准确的测量值。在此，基于体模实验推导了一种考虑FDG渗漏放射性的放射性估计校正公式。此外，为了确定校正公式是否能准确计算SUV，我们进行了一项志愿者研究。

方法

通过将转换常数从1.0、0.1改变为0.01来显示图像，并基于图像反转验证可校正计数的范围。为了通过成像估计FDG渗漏的放射性，测量渗漏的计数，使用交叉校准因子（CCF）将其转换为放射性浓度，并乘以通过成像测量的体积。在体模研究中评估了显著影响计数的三个因素，即计数率性能、部分容积效应和串扰，以便推导校正公式。此外，为了阐明校正公式的准确性，我们将其附着于右肘部。

结果

当转换常数为0.1时，在<或=1.565MBq/ml时没有图像反转。在此浓度以下，平均检测率为90%。这表明计数率性能可在<或=1.0MBq/ml时进行校正。串扰研究表明相邻放射性浓度对FDG渗漏的影响不显著。基于对部分容积效应和计数率性能的研究，得出以下公式：对于>或=28mm的渗漏渗漏放射性（MBq）=正电子发射断层扫描（PET）放射性（MBq）×0.9。对于>或=15mm但<28mm的渗漏渗漏放射性（MBq）=PET放射性（MBq）×0.9×（0.0517×渗漏大小（mm）-0.4029）。在一项渗漏10MBq的志愿者研究中，使用该公式重新计算的SUV实现了99.97%的校正，而在渗漏10MBq时，SUV实现了67.5%的校正，校正效果较差。