Tsuji A, Kojima A, Matsumoto M, Oyama Y, Tomiguchi S, Kira T, Takagi Y, Shimomura O, Takahashi M
Departinent of Radiology, Kumamoto University School of Medicine, Japan.
Ann Nucl Med. 1999 Oct;13(5):317-23. doi: 10.1007/BF03164870.
We have developed a new method of crosstalk correction in simultaneous dual-isotope imaging with Tl-201 and I-123 by using crosstalk ratios and a blurring filter. Single isotope myocardial studies (10 for Tl-201 and 7 for I-123) were performed with a dual energy window acquisition mode and two low energy general-purpose collimators. Then two planar images acquired with dual energy windows for a Tl-201 line source and an I-123 line source were obtained to measure line spread functions (LSFs) and crosstalk ratios for each image. The line source experiments showed that the LSFs for the Tl-201 imaging window from the single Tl-201 source were very similar to those for the I-123 imaging window from the single Tl-201 source, but the LSFs for the Tl-201 imaging window from the single I-123 source had broad shapes which differed from those for the I-123 imaging window from the single I-123. To obtain accurate I-123 crosstalk images in the Tl-201 imaging window from the I-123 images in the I-123 imaging window, we designed a low-pass blurring filter. In 7 clinical I-123 MIBG studies, I-123 window images processed with this filter became very similar to the Tl-201 window image from the single I-123 source. The method proposed in this study can accurately correct the crosstalk in dual isotope studies with Tl-201 and I-123 and is easily applicable to conventional gamma camera systems with any dual energy window acquisition mode.
我们通过使用串扰比和模糊滤波器，开发了一种在同时进行铊-201（Tl-201）和碘-123（I-123）双同位素成像时进行串扰校正的新方法。采用双能窗采集模式和两个低能通用准直器进行单同位素心肌研究（Tl-201的10例和I-123的7例）。然后获取用双能窗采集的Tl-201线源和I-123线源的两幅平面图像，以测量每幅图像的线扩展函数（LSF）和串扰比。线源实验表明，来自单个Tl-201源的Tl-201成像窗的LSF与来自单个Tl-201源的I-123成像窗的LSF非常相似，但来自单个I-123源的Tl-201成像窗的LSF具有较宽的形状，与来自单个I-123的I-123成像窗的LSF不同。为了从I-123成像窗中的I-123图像获得Tl-201成像窗中准确的I-123串扰图像，我们设计了一个低通模糊滤波器。在7例临床I-123间碘苄胍（MIBG）研究中，用该滤波器处理的I-123窗图像变得与来自单个I-123源的Tl-201窗图像非常相似。本研究提出的方法可以准确校正Tl-201和I-123双同位素研究中的串扰，并且很容易应用于具有任何双能窗采集模式的传统伽马相机系统。
