99mTc标记新型硼酸结构快速心肌灌注显像药物的制备及初步显像评价

Preparation and Preliminary Imaging Evaluation of a Group of Novel Rapid 99mTc-Labeled Boric Acid Derivatives Tracers for Myocardial Perfusion Imaging

  • 摘要: 99mTc-TEBO为临床批准的快速心肌灌注显像药物,该药物初始摄取高,但心肌滞留不稳定,为此,本研究通过优化其硼酸结构,分别制备标记物99mTc-2SP、99mTc-4LPA及99mTc-2MDM,制备时间均为30 min,均为无色澄明液体,放化纯度均>95%,分别在健康小型猪体内进行SPECT动态显像,并与99mTcTEBO进行对比。结果表明:99mTc-TEBO注射后0~5 min,左室心肌快速摄取,但随后心肌放射性迅速洗脱,在10 min时心肌约洗脱至峰值的75%,与心血池放射性浓度比值为1.63。99mTc-2SP引入2-甲磺酰基吡啶-5-硼酸基后心肌初始摄取高,心肌滞留时间明显延长,心肌洗脱较缓慢,左室心肌均清晰显影,在第10 min时心肌摄取仍可保持峰值的95%,与心血池放射性浓度比值为3.75,明显高于99mTc-TEBO。而另外两种显像剂99mTc-4LPA和99mTc-2MDM在注射后15 min内显像不理想。因此,99mTc-2SP是有潜力的心肌灌注显像药物。

     

    Abstract: Nuclear cardiology plays an important role in management of cardiac patients with known or suspected coronary artery disease (CAD). CAD is the leading cause of premature death and permanent disability. Myocardial perfusion imaging (MPI) with radiotracers is a non-invasive technique that shows the heart function and the areas of perfusion defects. In order to evaluate perfusion defects accurately, the radiotracer used in MPI studies must be taken up into myocardium in proportion to the regional myocardial blood flow. At present, 99mTc-TEBO is commonly used in clinic for rapid myocardial perfusion imaging, which has high initial uptake but poor myocardial retention, so it is necessary to optimize its structure. In this study, a group of novel 99mTc-labeled rapid boric acid derivatives tracers for myocardial perfusion imaging, including 99mTc-2SP, 99mTc-4LPA and 99mTc-2MDM were prepared in this study. The preparation time of these tracers was 30 min, and all of them were colorless clear liquid. The radiochemical purity of the three tracers was > 95%, respectively. The above tracer agents were used to perform SPECT dynamic imaging in healthy miniature pigs and compared with 99mTc-TEBO. After 99mTc-TEBO injection, rapid uptake was shown in left ventricular myocardium within 0.5 min, but the myocardial radioactivity decreased rapidly to about 75% of the peak value and the ratio of the radioactivity between myocardium/blood pool was 1.63 at 10 min. Compared with 99mTc-TEBO, 99mTc-2SP had prolonged retention and slower elution in myocardium within 15 min after the injection when the 2-methylsulfonyl pyridine-5-boric acid group was introduced into the 99mTc-2SP structure. The myocardial radioactivity still maintained 95% of the peak value, and the ratio of radioactivity between myocardium/blood pool was 3.75, which was significantly higher than that of 99mTc-TEBO. However, the other two imaging agents 99mTc-4LPA and 99mTc-2MDM showed poor uptake in myocardium within 15 min after injection. In conclusion, 99mTc-2SP was an ideal boric acid derivatives tracers for myocardial perfusion imaging and has prospect for clinical application in future.

     

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