^(99m)Tc标记抗心肌肌凝蛋白轻链单克隆抗体在体亲梗死心肌放射免疫显像研究

IN VIVO IMAGING OF TECHNETIUM-99m-LABELLED ANTIMYOSIN LIGHT CHAIN MONOCLONAL ANTIBODY (AMLCA) IN EXPERIMENTAL MYOCARDIAL INFARCTION IN DOGS

为探讨99mTc标记抗心肌肌凝蛋白轻链单克隆抗体 (AMLCA)在体亲梗死心肌放射免疫显像的可行性 ,5只狗静脉注射99mTc AMLCA后 2、4、8、2 4h ,对血液标本和各脏器进行放射性测量和γ像机显像。对 2例心肌梗死狗进行在体99mTc AMLCA心血池显像和99mTc MIBI心肌灌注显像 ,并对其离体心脏进行γ显像和双感兴趣区双核素放射性测量。结果表明 ,注射后 2、4、8、2 4h ,血液99mTc AMLCA放射活性分别是 (5 1 5± 5 2 ) %、(2 7 3± 3 1) %、(12 3± 1 8) %和 (5 6± 0 6 ) % ,心脏放射性分别是 (11 2± 1 2 ) %、(6 7±1 5 ) %、(5 5± 0 9) %和 (2 8± 0 3) % ,注射 2h在体心脏γ显像最清晰 ,以后逐渐衰减 ,注射 2 4h心脏不再显像。心梗狗在体99mTc AML CA心血池显像与99mTc MIBI心肌灌注显像比较 ,前者放射浓聚区与后者放射缺损区吻合 ,其离体心脏γ显像放射性浓聚区TTC染色证实是梗死心肌 ,双感兴趣区双核素放射性测量表明 ,梗死心肌摄取99mTc AMLCA具有特异性。本研究提示 ,99mTc AMLCA在血中清除迅速且能被梗死心肌特异性摄取 ,在体99mTc AMLCA心血池显像能显示梗死心肌 ,99mTc

The biodistribution and the radio activity in blood clearance of 99m Tc AMLCA were determined in 5 normal dogs by whole body imaging and measuring the radio activity in blood samples at 2,4,8 and 24h after 99m Tc AMLCA injection. The feasibility of imaging of the site of myocardial infarct was determined in 2 of the experimental MI dogs by demonstration of the left ventricle blood pool imaging (LVBPI) with 99m Tc AMLCA and by subsequent imaging of the excised heart. The results showed that the plasma concentration of 99m Tc AMLCA decreased rapidly from 51 5%±5 2% at 2nd hr to 27 3%±3 1% at 4th, 12 3%±1 8% at 8 hr and 5 6%±0 6% at 24th after the injection. The LVBPI in one MI dog showed that the region of the radionuclide concentration of 99m Tc AMLCA corresponded to region of absence of 99m Tc MIBI. The scintigraphy in another MI dog heart slices showed that the region of the radionuclide concentrate of 99m Tc AMLCA corresponded to the region of triphenyltetrazolium chloride (TTC) staining. The measurement of double radionuclides in the double interesting region in the MI dog heart slices indicated that the infarct myocardium uptook 99m Tc AMLCA specifically. These findings suggested that 99m Tc AMLCA scintigraphy might be a new approach for detecting and localizing MI