心肌显像剂99TcmN(NOEt)2动物药理实验和再分布特性

目的对心肌显像剂99Tcm-氮-二(N-乙基-N-乙氧基二硫代氨基甲酸盐)[N(NOEt)2]进行临床前药理实验和再分布特性研究.方法制备的99TcmN(NOEt)2放化纯度>95%,对5只实验犬进行了血药动力学、体内生物分布和显像、99TcmN(NOEt)2和201Tl缺血心肌再分布显像对比和毒性的研究.结果 99TcmN(NOEt)2的放化纯度平均为(98.41±0.46)%,血清除T(α)1/2=(2.8±0.1) min,T(β)1/2=(142.7±32.7) min,总清除速率Cl=(292.3±117.1) mL/h.显像示99TcmN(NOEt)2能被心肌较快地摄取,肺中摄取清除快速,肝摄取较高.在10、30、60、90、120 min时,心肌摄取为(4.27±0.21)、(5.3±1.48)、(5.3±0.66)、(4.0±0.53)和(3.67±0.35)%ID;心/肺和心/肝比值分别是1.24±0.31、2.03±0.45、2.33±0.31、2.23±0.5、2.07±0.49和0.94±0.08、0.78±0.15、0.56±0.22、0.53±0.22、0.38±0.15.在30和60 min时心肌影像最为清晰.99TcmN(NOEt)2在犬缺血心肌中有再分布特征,并与201Tl的再分布显像自身对照结果一致.结论 99TcmN(NOEt)2是很有价值的心肌灌注显像剂,并有与201Tl一样的再分布特征.     

99 TcmN-NOEt门控心肌显像的临床应用

目的评价99Tcm-N-乙氧基,N-乙基氨荒酸钠(N-NOEt)门控心肌显像的临床应用价值,并与99Tcm-甲氧基异丁基异腈(MIBI)进行比较.方法 20例受检者分为2组,组1左室射血分数(LVEF)≥50%,共13例,平均年龄(49.9±14.7)岁;组2LVEF<50%,共7例,平均年龄(50.9±12.9)岁.受检者静脉注射99TcmN-NOEt 925 MBq后分别于30和120 min行静息门控心肌断层显像,并计算心/肺(H/L)比值.组2 6例、组1 1例在3 d内行99Tcm-MIBI门控心肌显像,将每例受检者的左室心肌分为9个节段,以常规4分法进行打分.结果组1 30及120 min H/L比值分别为1.47±0.47和1.59±0.53(t=0.31, P>0.05),2次显像的LVEF、舒张末期容积(EDV)和收缩末期容积(ESV)差异无显著性(P>0.05).组2 30和120 min H/L比值分别为0.72±0.11和0.89±0.11(t=2.93, P<0.05),2次显像的LVEF,EDV和ESV间差异无显著性(P>0.05).2组间的H/L比值和LVEF、EDV、ESV差异有显著性.NOEt与MIBI所得LVEF,EDV和ESV值基本一致(P>0.05),但NOEt的不正常节段数(21个)较MIBI(17个)为多,两者的一致性为93.65%, Kappa±s=0.87±0.12,得分分别为2.00±0.84(MIBI)和2.38±0.84(NOEt)(t=1.39, P>0.05).结论①左心功能受损时, 肺摄取99TcmN-NOEt增多.②99TcmN-NOEt与99Tcm-MIBI所测得的LVEF,EDV和ESV基本一致.③99TcmN-NOEt测得的心肌放射性缺损的范围及程度较MIBI广泛而严重.     

99Tcm-MIBI半定量显像对甲状腺癌的诊断价值

目的评价半定量99Tcm-甲氧基异丁基异腈(MIBI)显像法对甲状腺癌的诊断价值.方法对269例经病理检查或细胞学证实的甲状腺结节患者的99Tcm-MIBI显像结果进行分析,计算其5和60 min摄取比值(UR),并以甲状腺良性结节组UR值的+s为诊断阈值,分析假阳性和假阴性.结果甲状腺良性结节组5和60 min UR分别为0.806±0.192和0.847±0.189,而甲状腺癌组UR值分别为1.839±0.734和1.675±0.551,同组两时相比较P>0.05,而组间两时相比较P<0.001.以良性结节组+s为诊断阈值,99Tcm-MIBI对甲状腺癌诊断的灵敏度、特异性和准确性分别为89.24%、93.82%和87.36%,假阳性率和假阴性率分别为15.78%和12.09%,阳性预测值和阴性预测值分别为 77.57% 和93.83%.结论 99Tcm-MIBI半定量显像能较好地鉴别甲状腺结节的良恶性,但缺乏特异性,甲状腺腺瘤和结节性甲状腺肿易出现假阳性.     

心肌显像剂[99Tcm(CO)3(MIBI)3]+和99Tcm-MIBI药理实验对比研究

目的对心肌显像剂羰基99Tcm-甲氧基异丁基异腈(MIBI)([99Tcm(CO)3(MIBI)3]+)和99Tcm-MIBI进行动物药理对比研究.方法制备[99Tcm(CO)3(MIBI)3]+注射液,放化纯85%.实验犬3只,每次静脉注射剂量555 MBq,通过动态采集、全身显像和采集血样,获得药代动力学参数、体内生物分布、靶/非靶比值和药效学结果.结果 [99Tcm(CO)3(MIBI)3]+符合一次静脉给药的药代动力学二室模型,快相清除半衰期T(α)1/2=(1.33±0.12) min,慢相清除半衰期T(β)1/2=(102.33±25.58) min,总清除速率(CL)=(401.33±73.51) mL/h.心、肝、肺时间-放射性曲线显示[99Tcm(CO)3(MIBI)3]+肝摄取曲线幅度低于心肌曲线,而99Tcm-MIBI肝曲线明显高于心肌曲线.10、30、60、90和120 min[99Tcm-(CO)3(MIBI)3]+在心、肺、肝百分注射剂量(%ID)与99Tcm-MIBI比较,前者心肌摄取较高,肺本底较低,肝摄取低.[99Tcm(CO)3(MIBI)3]+心/肺和心/肝比值均高于99Tcm-MIBI,差异有显著性,P均<0.01.静脉注射[99Tcm(CO)3(MIBI)3]+后10～120 min均可获得清晰的心肌图像,肝胆排泄较快,肝内放射性较低,左室下壁不受肝影影响,无需脂餐促进肝胆排泄.结论 [99Tcm(CO)3(MIBI)3]+有望成为一种新的心肌灌注显像剂.     

肺良恶性病变99Tcm-MIBI显像与肺癌DNA含量分析

目的探讨99Tcm-甲氧基异丁基异腈(MIBI)诊断肺部良恶性病变的价值及肺癌摄取99Tcm-MIBI比值与癌细胞DNA含量的关系.方法 27例肺良性病变及46例肺恶性病变患者均行99Tcm-MIBI早期和延迟肺显像,并测定病变靶/非靶(T/NT)摄取比值(UR).对肺恶性病变组中的24例手术标本进行DNA含量测定,计算DNA含量指数(DI),并与术前99Tcm-MIBI UR进行相关分析.结果良性病变组延迟UR为1.13±0.19,肺癌组为1.45±0.21,两者比较P<0.01;延迟相目测观察及UR诊断肺癌的灵敏度、特异性、准确性分别为91.3%,55.6%,78.1%和80.4%,62.9%,73.9%;正常支气管黏膜上皮(二倍体)细胞DI=0.68±0.21,肺腺瘤DI=0.51±0.27,肺癌组DI=1.43±0.33(与前两者比较,P均<0.01).肺癌组异倍体细胞出现率为83.3%.肺癌组DI与延迟UR的r为0.32.结论 99Tcm-MIBI不是理想的鉴别诊断肺部良恶性病变的显像剂;延迟相UR有可能间接反映癌细胞DNA含量.     

99Tcm-MIBI SPECT/CT同机融合断层显像对肺癌及其转移淋巴结的诊断价值

目的探讨99Tcm-MIBI SPECT/CT同机融合断层显像对肺癌及其转移淋巴结的诊断价值.方法以术后病理诊断为依据,对57例肺部占位性病变患者的99Tcm-MIBI SPECT/CT显像结果分良性和肺癌两组进行分析,计算其5min、60min平面以及60min SPECT/CT三维融合断层显像的摄取比值(UR);以肺部良性病灶组UR值的+1s为诊断阈值,对肺癌原发灶及其转移淋巴结的诊断效能进行评价.结果17例肺部良性病灶组其5min和60min平面以及60min SPECT/CT三维融合断层显像的摄取比值(UR)分别为1.05±0.16、0.97±0.22、1.51±0.39,而40例肺癌组其UR值分别为1.41±0.22、1.37±0.23、2.18±0.61同组两时相比较P>0.05,而组间两时相比较P<0.05.以良性结节+1s为诊断阈值,99Tcm-MIBI对肺癌诊断的灵敏度、特异度和准确度分别为90%(36/40)、82.35%(14/17)和87.72%(50/57);假阳性率和假阴性率分别为17.65%(3/17)和10%(4/40);阳性预测值和阴性预测值分别为 92.31%(36/39)和77.78%(14/18).40例恶性病变患者共检出转移淋巴结19个,其CT/SPECT断层融合图像的UR值为1.82±0.37.结论99Tcm-MIBI SPECT/CT同机融合断层显像对肺癌及其转移淋巴结具有较高的诊断价值.     

~(99m)Tc-N(NOEt)_2肿瘤显像的动物实验研究

目的:评价99mTc-N(NOEt)2在小鼠肝脏肿瘤模型显像中的应用价值。方法:昆明种小白鼠21只,随机选择12只行99mTc-N(NOEt)2体内分布试验,采用百分注射剂量率(%ID)评定。另外9只用作肿瘤实验鼠,每只种植H22肝癌模型小鼠腹水0.1ml制备动物模型,肿瘤直径大于2cm后开始实验,采用SPECT显像技术评定Tc-N(NOEt)2在肿瘤显像中的作用,记录T/N作为评定指标,并与99mTc-MIBI在相同条件下进行比较。结果:99mTc-N(NOEt)2在肝脏、肺、肾、心脏分布较多。在肺中代谢快,心/肺比值随时间延长而增大,120min时达最大值。肝脏、肾脏于90min时摄取率最高,然后开始下降。99mTc-N(NOEt)2组T/N120min时最高,此时肝脏的摄取已开始下降,显像的最佳时间为120min。在注射后30min和90min时99mTc-N(NOEt)2与99mTc-MIBI的T/N差异无显著性意义,在120min时99mTc-N(NOEt)2摄取明显高于99mTc-MIBI。结论:99mTc-N(NOEt)2在小鼠体内分布快;以心脏摄取较快,摄取率较高,排泄慢,因此此药物适合心肌显像,但其在肺中的摄取高,有可能干扰心肌显像。99mTc-N(NOEt)2在小鼠肝癌显像中有肯定意义,在120min时肿瘤显像最佳,99mTc-N(NOEt)2有可能成为一种新型的肝脏肿瘤显像剂。     

99 Tcm-MIBI门控心肌显像ECTS软件测量左室射血分数

目的评价99Tcm-甲氧基异丁基异腈(MIBI)门控心肌显像Emory Cardiac Toolbox softwere (ECTS)处理软件测量左室射血分数(LVEF)的临床价值.方法 31例受检者,采用静息-多巴酚丁胺负荷一日法,行99Tcm-MIBI门控心肌断层显像,用ECTS软件测量LVEF,并于1周内完成平衡法心室显像,比较2种方法测量LVEF的相关性及一致性.结果①ECTS软件分析左室功能参数的重复性很好,变异系数(CV)均小于2%.②99Tcm-MIBI门控心肌显像ECTS软件测定LVEF值与平衡法心室显像测定值相关性良好(r=0.893,P<0.001).③ECTS软件测定的LVEF值[(57.3±2.93)%]较心室显像测定值[(46.6±2.86)%]高(t=7.76,P<0.001).结论 99Tcm-MIBI门控心肌显像ECTS软件与平衡法心室显像测定LVEF值具有较好的相关性,但前者测量值较后者高.99Tcm-MIBI门控心肌显像ECTS软件测定LVEF值能否完全取代平衡法心室显像测定,尚需进一步研究.     

~(99m)Tc-YIGSR与~(99m)Tc-MIBI肿瘤细胞摄取比较研究

目的利用肿瘤细胞表面含有大量层粘素受体,而且能与层粘素特异性结合机制,研究99mTc-YIGSR(层粘蛋白-小分子肽)作为一种新型的肿瘤显像剂,在埃氏腹水瘤细胞(EAC)中的摄取并与MIBI进行比较.方法①99mTc-MAG3-YIGSR 探针的制备利用S-已基-琥铂酰亚胺-巯已甘肽(S-Acetly-NH3-MAG3)作为螯合剂,在适当还原剂作用下,将99mTc标记到层粘素-YIGSR上,用Sphadex G10凝胶柱纯化,根据放射性计数及280nm紫外吸光值合并各峰管,利用纸层析进行放射性化学纯度分析.②细胞培养及细胞存活率测定EAC在含小牛血清的1640细胞培养液中悬浮培养,用台盼兰排除法计数活细胞.③细胞动力学研究用放射性核素示踪法研究EAC在37℃和22℃时对99mTc-YIGSR及99mTc-MIBI的摄取.结果①99mTc-YIGSR标记率为(62±3)%,放化纯为95%,99mTc-MIBI标记率为(96±2)%,放化纯为98%.②细胞存活率随孵育时间延长而下降,实验前细胞存活率为96%±1%,孵育2h细胞及3h存活率分别为(96±1)%及(90±2)%,均在85%以上符合实验要求.③37℃ 60min时,EAC对99mTc-YIGSR及99mTc-MIBI的摄取峰值分别为(43.16±2.4)%和(24.4±1.8)%;在22℃时EAC摄取峰值分别为(26.5±2.1)%和 (9.47±1.9)%.结论在相同条件下EAC对99mTc-YIGSR摄取峰值高于99mTc-MIBI,更适用于肿瘤显像,在临床上具有潜在的应用价值.     

门控99Tcm-MIBI/18F-FDG双核素同时采集显像评价左心室功能

目的探讨门控99Tcm-甲氧基异丁基异腈(MIBI)/18F-脱氧葡萄糖(FDG)双核素同时采集(DISA)显像评价左心室功能的临床价值.方法 77例冠心病患者行门控DISA,其中53例行X线左心室造影(LVG),分别比较LVG心室射血分数(EF)值和DISA法门控99Tcm-MIBI和18F-FDG 同时显像所得EF值.局部室壁运动行Kappa值比较.结果门控99Tcm-MIBI和门控18F-FDG显像所得EF值间相关性高(r=0.90,P<0.001).两者与LVG EF值相关性均高(r分别为0.86和0.85,P均<0.001).门控99Tcm-MIBI和18F-FDG显像与LVG比较Kappa值分别为0.765和0.742.结论门控99Tcm-MIBI/18F-FDG DISA可同时了解左室心肌灌注、代谢及功能,提供左心室功能的重要信息,有重要的临床价值.     

Clinical comparison of 99mTc-HMDP and 99mTc-MDP

^99mTc-Hydroxymethylene diphosphonate (HMDP) was compared to ^99mTc-methylene diphosphonate (MDP) with respect to image quality, lesion detectability, and the uptake ratios of normal bone to soft tissue (B/S), metastatic bone to soft tissue (M/S) and bone metastases to normal bone (M/B) at 2 and 3 h after injection in the same subjects. Thirty-three patients with bone metastases were examined in six nuclear-medicine departments, with each center using its usual bone-scanning protocol which was identical for both compounds in the same patient. The uptake of ^99mTc-HMDP in normal bone (B/S) was significantly higher than that of MDP at 2 and 3 h, but there were no significant differences between the two compounds with regard to the M/S or M/B or M/B ratios. The M/B of HMDP at 2 h was not significantly different from that of MDP at 3 h, the latter showing a significantly higher B/S and M/S ratio. All lesions were detected with both compounds, even at 2 h. The image quality was rated as follows (in decreasing order): HMDP (3 h), MDP (3 h), HMDP (2 h), and MDP (2 h). HMDP was shown to be a useful bone-imaging agent, especially when shorter intervals between injection and recording are required.     

Clinical comparison of bone scintigraphy with 99Tcm-DPD, 99Tcm-HDP and 99Tcm-MDP

The bone-imaging agents MDP, DPD and HDP were compared radiochemically (only minor differences were found) in 12 patients with prostatic and 12 patients with breast carcinoma. Each patient received both MDP and either DPD or HDP. The scintigraphic examinations were compared visually and quantitatively. The uptake ratio normal bone/soft tissue was higher for DPD and HDP than for MDP. The ratio pathologic bone/normal bone was highest for MDP, particularly for prostatic carcinoma. The differences in this ratio for breast carcinoma were in general non-significant. The observed differences were minor and of little practical importance.     

Effect of milking efficiency on 99Tc content of 99mTc derived from 99mTc generators

Calculation was made of the effect of milking efficiency on the 99Tc content of 99mTc derived from 99mTc-generators. Reduced milking efficiency was shown to lead to an increase in the 99Tc/99mTc ratio. Levels of 99Tc were determined in samples from both column and solvent extraction generators using a HPLC procedure. It is recommended that producers of 99mTc from solvent extraction generators should ensure that complete generator milking is performed daily.     

Pharmacokinetic characteristics of 99mTc-Ethylene-l-dicysteine (99mTc-EC)

BACKGROUND: Ethylenedicysteine-99mTc (99mTc-EC) has been more and more commonly applied in dynamic studies as well as for clearance determinations. However, it was necessary to investigate in detail the pharmacokinetic characteristics of the radiopharmaceutical which may be important for its applicability in assessment of renal function. RESULTS: Kidney images obtained from renoscintigraphy are characterised by excellent quality without visualisation of the organs adjacent to kidneys (liver, spleen). Renoscintigraphic curves demonstrate typical shapes with TMAX and T1/2 values not differing from the corresponding values obtained for other radiopharmaceuticals (99mTc-MAG3, 131I-OIH). In plasma, 99mTc-EC binds with proteins to a considerably lesser degree (c. 1/3) than 131I-OIH (c. 2/3), or 99mTc-MAG3 (> 9/10). No binding of 99mTc-EC with erythrocytes has been demonstrated, whereas 131I-OIH attaches to or penetrates the red blood cells (10-12%). 99mTc-EC is quickly excreted from the organism: 40 min after i.v. injection up to 70% of the administered radiopharmaceutical is found in urine, and at 1 and 1.5 h after the administration 80% and 95%, respectively. The distribution of 99mTc-EC in the organism can be described in a fully satisfactory way by means of an open two-compartment model, which allows this model to be used for clearance determinations. Comparison of the values of renal plasma clearance without collection of urine with the values determined by means of measurement of activity excreted with urine and mean blood concentration over a finite time interval leads to the conclusion that extrarenal plasma clearance of this compound (via the liver?) is negligible and amounts to c. 17 ml/min (5-6% of the total). The obtained correlation between clearance values for 99mTc-EC and 131I-OIH supports the contention that extrarenal excretion rate of 99mTc-EC (through the liver and bile ducts) is lower than the corresponding rates of either 131I-OIH or 99mTc-MAG3. A very close correlation between clearance values for 99mTc-EC and ERPF (131I-OIH clearance) and between their extraction constants (r = 0.91 and 0.92, respectively), allows for the introduction of 99mTc-EC to the assessment of renal function instead of 131I-OIH. Effective dose to the patient from unit activity of 99mTc-EC is comparable with that resulting from administration of other radiopharmaceuticals labelled with 99mTc.     

Results of regular study on radionuclidic purity of 99mTc obtained from 99Mo-99mTc generators

A total of 39 ^99mTc eluates obtained from 9 ⁹⁹Mo-^99mTc generators delivered by The Radiochemical Centre Amersham during one year was studied with regard to their radionuclide purity. Using a Ge(Li) spectrometer the contaminants ⁶⁰Co, ¹⁰³Ru, ¹³¹I, ¹³⁴Cs, ¹⁴⁰Ba, ¹⁴⁰La and ¹⁸⁸Re were found in ^99mTc-eluates with average levels ranging from 2.9x10^-3 to 2.8x10^-1 per cent of ^99mTc activity. The additional total body absorbed dose caused by these contaminants, as calculated from their average content in ^99mTc eluates, was less than 1% of the dose due to ^99mTc pertechnetate.