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.

Key words: ^99mTc, myocardial perfusion imaging, boric acid derivatives

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。

关键词: ^99mTc, 心肌灌注显像, 硼酸化合物