99Tcm sestamibi--a new agent for parathyroid imaging

Parathyroid imaging using 99Tcm sestamibi has been carried out prior to surgery in five patients with hyperparathyroidism and the results compared with a standard preoperative localization technique using 201Tl (thallous chloride). The 99Tcm sestamibi correctly localized all abnormal glands and showed higher parathyroid to thyroid uptake in three of four parathyroid adenomas. Both agents showed localization in a thyroid adenoma. The higher uptake of sestambi and better imaging properties of its 99Tcm radiolabel means that the agent may replace thallium for routine preoperative parathyroid localization.     

99Tcm hydroxyethyl starch: a potential radiopharmaceutical for lymphoscintigraphy

The usefulness of 99Tcm hydroxyethyl starch (99Tcm HES) has been evaluated for visualization of lymphatic channels and lymph nodes. 99Tcm HES was prepared with a labelling efficiency higher than 95%. Its usefulness for imaging lymphatic channels and lymph nodes were compared to 99Tcm human serum albumin (99Tcm HSA), 99Tcm dextran (99Tcm DXT) and 99Tcm sulphur micro colloid (99Tcm SMC) in rabbits. 99Tcm HES showed a good visualization of lymphatic channels and lymph nodes and it had the highest clearance rate from the injection site (P less than 0.01). 99Tcm HES showed higher uptake by the nodes than 99Tcm DXT (P less than 0.001) at 90 min post injection. The concentration of 99Tcm HES in the lymphatic channels was higher than that of 99Tcm SMC at 90 min post injection (P less than 0.001). Preliminary studies of 99Tcm HES in humans provided high-quality lymphoscintigrams of the leg, and the pelvic and para aortic lymph nodes in less than 10 min post injection. In addition, partially and completely obstructed lymphatics could be differentiated from the normal one. Hence 99Tcm HES is a potential radiopharmaceutical for visualization of lymphatic channels and nodes.     

Pre-surgical localization of ectopic parathyroid glands using three-dimensional CT imaging, 99Tcm sestamibi, and 99Tcm tetrofosmin imaging.

We describe two patients with ectopic parathyroid glands evaluated with 99Tcm sestamibi, 99Tcm tetrofosmin, and three-dimensional computed tomography (3D-CT). Radionuclide images of the neck were acquired at 10 min, and at 2-3 h after radiopharmaceutical injection, and showed intense uptake in the ectopic parathyroid tissue. These patients also underwent contrast enhanced CT imaging with 3D reconstructions which were evaluated for ability to visualize critical anatomical structures, e.g. blood vessels and parathyroid glands. Based on 3D-CT images, surgical planning was altered in one of the two patients studied. In conclusion, reconstructed 3D-CT images provided useful anatomical localization of ectopic parathyroid glands identified on 99Tcm sestamibi and 99Tcm tetrofosmin imaging. This anatomical information aided surgical planning of gland resection.     

99锝m N-2-巯基吡啶-N-氧化物与99锝m-甲氧基异丁基异腈对犬急性心肌梗死模型的对照研究

目的 在正常和心肌梗死犬模型上,研究99TcmN-2-巯基吡啶-N-氧化物(99TcmN-MPO)的药物代谢动力学特征、生物学分布特征和对急性心肌梗死的诊断能力,并与传统示踪剂99锝m-甲氧基异丁基异腈(99Tcm-MIBI)进行对比研究.方法 正常杂种犬12只.静脉注射99TcmN-MPO,于不同时间点(30 s及1、2、3、4、5、10、20、30、40、60和90 min)静脉分别采血1 ml,经γ探测器测量其放射活性;注药后10、20、30、60、90及120 min行全身SPECT显像,并于不同器官上各取同样大小的ROI,测量其放射性计数进行定量研究.每只犬均注射相同剂量的99TcmMIBI,进行相同的实验作为对照.介入学方法构建犬急性心肌梗死模型,24 h后,静脉注入99TcmN-MPO(5只)和99Tcm-MIBI(5只),并于注药后30、60min进行心肌SPECT显像.结果 在静脉注射90 min内,99TcmN-MPO和99Tcm-MIBI均表现为快速的血液清除.两种示踪剂的初始注射剂量均为370 MBq.注射后1 min,每毫克血浆的放射活性小于初始注射剂量的50%[99TcmN-MPO为(35.77±6.31)%ID/mg;99Tcm-MIBI为(34.46±6.83)%ID/mg],30 min时＜5%[99TcmN-MPO:(3.11±1.44)%ID/mg;99Tcm-MIBI:(2.93±0.39)%ID/mg].99TcmN-MPO在心脏的浓聚明显,且存留时间很长,由于其在肝脏清除的速度较快,因此可获得良好的心/肝摄取比值,注射后10 min为0.54±0.06,30 min为1.02±0.06,60 min上升到1.38±0.06.相比之下,99Tcm-MIBI的心/肝摄取比值上升较为缓慢(注射后10 min为0.46±0.03,30 min为0.63±0.03,60 min为0.62±0.12).犬心肌梗死后SPECT心肌断层扫描显示,在注射99TcmN-MPO 30 min后,心脏与肝脏分界清楚,可清楚显示心肌缺血、梗死灌注缺损区域、范围和程度;而99Tcm-MIBI注射后60 min,心脏和肝脏的分界依然不清,尤其是肝脏的高放射性对心脏下壁和左心室壁的影响很大,对心脏左心室壁的心肌梗死灌注缺损区域的显示不佳.结论 99TcmN-MPO具有心肌摄取量较高,肝脏代谢快的特点,是一种具有广阔临床应用前景的SPECT心肌灌注成像显像剂.

Abstract：

Objective The purpose of the present study is to compare the pharmacokinetic and biodistribution properties of 99Tcm N-mercaptopyridine-N-oxide (99 Tcm N-MPO) with 99 Tcm-sestamibi (99 Tcm-MIBI) in normal dogs, and to investigate the potential of 99TcmN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Methods Twelve healthy mongrel dogs were injected intravenously with 99TcmN-MPO (n = 6) or 99Tcm-MIBI (n = 6). Tracer kinetics in body fluids were determined by collecting blood of 1 ml via a femoral vein catheter at 30 s, 1,2,3,4,5, 10, 20, 30, 40, 60and 90 min post-injection (p. i.). The collected blood samples were weighed and counted for radioactivity in a γ-counter. Anterior and posterior planar γ-camera images were collected at 10, 20, 30, 60, 90, and 120 min after injection, with organ uptake quantified by region-of-interest (ROIs) analysis. For comparison, 99Tcm-MIBI was also evaluated in the same twelve dogs. Canine infarct models were set up by micro-invasive interventional embolization. SPECT images in the canine infarct model were collected 24 hours after myocardial infarction at 30 min and 60 min after the administration of 99Tcm N-MPO (n = 5) or 99Tcm-MIBI (n = 5). Results Both of 99Tcm N-MPO and 99Tcm-M1BI had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min [99TcmN-MPO: (35. 77 ± 6. 31)% ID/mg ,99Tcm-MIBI (34. 46 ± 6. 83) % ID/mg] and less than 5% at 30 min p. i. [99Tcm N-MPO(3. 11 ± 1.44) % ID/mg,99Tcm-MIBI (2.93 ±0. 39)% ID/mg] . After injection, 99TcmN-MPO showed significant accumulation in the myocardium and prolonged retention. This rapid liver clearance of 99TcmN-MPO led to favorable heart-to-liver ratios, reaching values of 0. 54 ±0. 06 at 10 min, 1.02 ±0. 06 at 30 min, and 1.38 ±0. 06 at 60 min p. i.In contrast, the heart/liver ratio of 99Tcm-MIBI remained low at all time points (0. 46 ± 0. 03 at 10 min,0. 63 ±0. 03 at 30 min, and 0. 62 ± 0. 12 at 60 min p. i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of 99TcmN-MPO, but not 99Tcm-MIBI. Conclusion The combination of high heart uptake and rapid liver clearance makes 99TcmN-MPO a promising new radiotracer for myocardial perfusion imaging.     

99Tcm标记异腈类配合物的研究进展

99Tcm标记的异腈类配合物是目前国内外应用最广泛的心肌灌注显像剂,在肿瘤的诊断方面也有重要应用.本文简要介绍了异腈配体合成及标记化合物的制备方法,并对99Tcm标记异腈类配合物的发展、分类及应用进展作了归纳总结.     

99Tcm (v) DMSA: the pituitary sign

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate head and neck tumours. It has a normal head and neck biodistribution to include the lacrimal glands, nasal mucosa and the blood-pool. Seventy-seven patients were studied of whom 63 had a head and neck malignancy. Of these patients, 19 (25%) exhibited positive accumulation of radioactivity in the region of the pituitary gland and this was a constant finding in those followed-up after treatment. Biodistribution studies in forty New Zealand white rabbits confirmed pituitary accumulation of 99Tcm (v) DMSA. The pituitary gland region should be included in the normal biodistribution of 99Tcm (v) DMSA.     

Lymphatic mapping with 99mTc-Evans Blue dye in sheep

Objective   ^99mTc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully discriminate the sentinel lymph node. The aim of this study was to investigate the potential of ^99mTc-EB as an agent to map the lymphatic system in an ovine model. Methods  Doses of ^99mTc-EB (23 MBq) containing EB dye (4 mg) were administered intradermally to the limbs of four anesthetized sheep, and they were then imaged over 20–30 min using a gamma camera. The study protocol was repeated using ^99mTc-antimony trisulfide colloid (ATC) and Patent Blue V dye. The lymph nodes (popliteal, inguinal, and iliac for hind limbs or prescapular for fore limbs) were identified with a gamma probe during the operative exposure, then dissected and counted in a large volume counter. Results  Simple and complex (dual) drainage patterns were visible on the scans, and the sentinel node was more radioactive than higher tier nodes in a chain, for both radiotracers. For ^99mTc-EB, maximum radioactive uptake was achieved at 3–6 min for popliteal lymph nodes, 12–14 min for iliac nodes, and 13–14 min for prescapular nodes. ^99mTc-ATC resulted in maximum radioactive uptake at 4–6 min for popliteal lymph nodes, 13 min for an inguinal node, 13–20 min for iliac nodes, and 18 min for a prescapular node. Following ^99mTc-EB injection, 15/15 lymph nodes harvested were all radioactive and blue. For ^99mTc-radiocolloid/Patent Blue V injection, 8/14 nodes were radioactive and blue, and 6/14 nodes were radioactive only. Conclusions  The soluble radiotracer ^99mTc-EB appeared to be a useful lymphoscintigraphic agent in sheep, in which radioactive counts from superficial lymphatic channels and lymph nodes were sufficient for planar imaging. In comparison with ^99mTc-antimony trisulfide colloid, both tracers discriminated the sentinel lymph node up to 50 min after administration; however, ^99mTc-EB had the advantage of providing radioactive (gamma probe) and color signals simultaneously during the operative exposure.     

Comparison of 99Tcm complexes (NEP-DADT, ME-NEP-DADT and HMPAO) with 123IAMP for brain SPECT imaging in dogs

Several new lipophilic 99Tcm complexes have recently been described as alternatives to N-isopropyl (123I) iodoamphetamine (123IAMP) for measurement of regional cerebral blood flow (RCBF). In this study we have compared brain uptake and blood clearance of 99Tcm-N-ethylpiperidine-diamino dithiol (99Tcm-NEP DADT), its 4-methylated derivative (99Tcm-Me-NEP-DADT) and 99Tcm-hexamethyl-propylene-amine-oxime (99Tcm-HMPAO) with that of 123IAMP in two dogs. Single photon emission tomography (SPECT) was employed to measure brain accumulation and retention of the four radiopharmaceuticals. Cerebral uptake of the 99Tcm complexes (0.8-1.1%) was lower than that of 123IAMP (1.6% of the injected dose). There was considerable extracerebral activity in the dog's head, especially in the olfactory and snout regions. Because of slow blood clearance 99Tcm-HMPAO showed high uptake in these regions. Brain uptake of 99Tcm-HMPAO reached a plateau 5 to 10 min after intravenous injection and remained constant for the entire study period (1 h). 99Tcm-NEP-DADT, on the other hand, showed significant clearance from the brain after reaching maximal uptake at 10 to 15 min after injection. However, brain imaging with these agents was possible during the first 20 min. The mechanism of brain uptake, as well as the relationship between brain uptake and RCBF need to be evaluated for each of the four radiopharmaceuticals.     

Evaluation of 99mTc-dextran as a lymphoscintigraphic agent in rabbits

Dextran (clinical grade, average mol. wt. 82,200) was labelled with 99mTc and the labelling efficiency was checked by paper and thin-layer chromatography and electrophoresis. The amount of free 99mTcO-4 was always less than 1%. The radiopharmaceutical was injected ID into the web space in hind legs of ten rabbits (200-600 microCi/0.05 ml). Scintigrams were taken at 10-min intervals up to 3 h in three rabbits. The injection site and the hind legs were massaged after injection in the other seven rabbits and scintigrams were taken at 10-min intervals up to 2 h. Blood samples were obtained at 5, 15, 30, 90 and 120 min in both groups. In addition a 180-min sample was also taken in the first group. At the end of the study the rabbits were killed and the popliteal lymph nodes and the organs were removed to be weighed and counted. Our results indicated a high concentration of radioactivity in the popliteal lymph nodes and massage at the injection site increased the average uptake of the popliteal lymph node from 1.12% +/- 0.77% to 4.28% +/- 1.57% at 3 and 2 h, respectively (P less than 0.001). In scintigrams the lymph channels and the nodes were very well visualised. The blood radioactivity levels were too low to present a background problem. With massage 30% of the injected dose was removed from the injection site in 2 h. We have shown that 99mTc-dextran is a good radiopharmaceutical for the visualisation of the lymph system and deserves further experimental and clinical studies.     

99Tcm—NGR—IFN-α2a在荷瘤小鼠体内分布及SPECT／CT显像

目的制备99Tcm标记天冬酰胺-甘氨酸-精氨酸（NGR）-干扰素-α2α（NGR—IFN—α2a）,并研究其在荷瘤小鼠体内的动态分布及显像。方法（1）双半胱氨酸（EC）作为双功能螯合剂合成EC—NGR—IFN-α2a,用MDP作为转移螯合剂,采用二步法对EC—NGR—IFN-α2a进行99Tcm标记,制备99Tcm-NGR-IFN-α2a,同时进行生物学活性测定,采用最小显著差异法t检验比较99Tcm-NGR-IFN-α2a与EC—NGR—IFN—α2a,NGR—IFN—α2a的生物活性;（2）建立肝癌MHCC97-H细胞严重联合免疫缺陷病（SCID）小鼠皮下移植瘤模型,采用随机数字表法分组,尾静脉注射99Tcm-NGR-IFN-α2a7．4MBq,分别于注射后0．5,1,2,4,6,8,12和24h处死小鼠。取血、肝、肾、心、脾、肺、胃、肠、骨骼、肌肉及肿瘤组织,测质量及测放射性计数,经物理衰变校正后计算％ID／g,以肿瘤组织为靶组织,以肌肉组织为非靶组织,计算不同时间点T／NT放射性比值;（3）荷瘤小鼠经尾静脉注射7．4MBq99Tcm-NGR-IFN-α2a,分别于注射后0．5,1,2,4,6,8,12和24h行静态平面及SPECT／CT显像,采用ROI技术,同上计算不同时间点的T／NT比值。结果99Tcm-NGR-IFN-α2a的标记率及放化纯均〉90％99Tcm-NGR-IFN-α2a在生理盐水中放置24h后放化纯为71％;标记后生物学活性未发生改变（t=0．416,0．120和1．300,P均〉0．05）;99Tcm-NGR-IFN-α2a经小鼠尾静脉注射后24h内,由泌尿和消化系统排泄,肾、肝、脾、肠道肿瘤的％ID／g值达到高峰的时间分别为8h,6h,6h,4h,高峰值分别为41．5±8．0,31．3±5．0,36．0±7．8,43．0±4．8;其在血液内清除迅速,其他组织器官的放射性随时间延长逐渐降低,rr／NT比值最高可达16．5,最佳显像时间为注射后4～8h。结论99Tcm-NGR-IFN-α2a易于制备,具有良好的靶向性和显像效果。放射性核素标记的NGR—IFN—α2a有望成为-种新的肿瘤血管靶向性诊断与治疗药物。     

Subcellular biodistribution of 99Tcm(V) DMSA in squamous carcinoma: a comparative study in humans and in an animal tumour model

Technetium-99m(99Tcm) (V) dimercaptosuccinic acid is a new imaging agent which has been used to evaluate head and neck squamous cell carcinoma (SCC). This study compared the subcellular biodistribution of 99Tcm(V)DMSA in an established rabbit tumour SCC model and in humans with head and neck SCC. In rabbits, approximately 17-37% of radioactivity was located on tumour cell membrane. Approximately 57-80% of radioactivity was located nonspecifically in tumour cytosol, only 2-6% was bound specifically to tumour mitochondria, and 1-4% bound specifically to microsomes. In humans, 25-45% of radioactivity was localized on tumour cell membrane and 28-60% localized nonspecifically in tumour cytosol. There was 11-20% of radioactivity specifically bound inside the cell to the mitochondria and 1-6% specifically bound to microsomes. These results show that although 99Tcm(V)DMSA is accumulated at sites of SCC, the localization process is nonspecific.     

99Tcm标记双半胱氨酸-脱氧葡萄糖的小鼠实验研究

目的研究^99Tc^m标记双半胱氨酸一脱氧葡萄糖(EGDG)在正常小鼠及荷S180肉瘤小鼠体内的分布规律。方法正常小鼠及荷S180肉瘤小鼠各铝只，分8组，实验前禁食。尾静脉注射^99Tc^m-EC-DG后计算不同时间在小鼠体内的分布及肿瘤与血液、肌肉、肺、肝的放射性比值。同时，取荷瘤小鼠5只，在注射后不同时间进行显像，计算T／NT比值。结果肿瘤组织与血液、肌肉、肺的放射性比值随时间延长逐渐上升，在4h都超过1．0。显像示随时间延长瘤体周围组织放射性逐渐下降，瘤体在4h时显影清晰。结论^99Tc^m-EC-DG可用于肿瘤的葡萄糖代谢显像。     

Pharmacokinetics, biodistribution and dosimetry of 99Tcm(V)DMSA in humans with squamous cell carcinoma

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.     

99Tcm-HL91 SPECT肺癌显像研究

目的研究99Tcm-HL91 SPECT肺癌显像与病理类型及病灶大小的关系.方法经病理证实的非小细胞肺癌患者共30例,利用SPECT仪采集注射740MBq99Tcm-HL91后2 h、4 h及6 h的前位、后位及侧位平面图像,利用感兴趣区(ROI)技术分别勾画各时相肿瘤(T)和对侧相应部位(N)ROI,计算T/N比值.患者于HL91 SPECT检查1周内行CT检查,测量CT图像上病灶大小.结果HL91选择性地浓集于肿瘤组织,浓集区域与CT显示肿瘤区域一致.显像清晰,以4 h效果为最佳,2 h、4 h和6 h T/N比值有统计学差异(P=0.041).鳞癌组及腺癌组4 h T/N差异无显著性(P=0.365),病灶大小与T/N无相关关系(P=0.702).结论99Tcm-HL91显像是一项有价值的肺癌检查手段,而与病理类型及病灶大小无相关性.     

新型心肌显像剂[99Tcm(N)(PNP5)(DBODC)]+猪心肌显像研究

目的 评价新型心肌显像剂[99Tcm(N)(PNP=5)(DBODC)]+在猪体内的药代动力学特征及生物分布特性.方法 利用药盒法制备[99Tcm(N)(PNP5)(DBODC)]+注射液.实验动物选7头实验用成年健康中华小型猪,由耳静脉注入[99Tcm(N)(PNP5)(DBODC)]+,分别于注射后2,5,10,15,30,45,60,75,90,120,150和180 min从猪后肢静脉进行血样采集以获得药代动力学参数,同时进行胸腹部平面系列显像,以观察该药物在猪体内的生物分布和靶/非靶比值,并与99Tcm-甲氧基异丁基异腈(MIBI)显像比较(采用配对t检验).结果 [99Tcm(N)(PNP5)(DBODC)]+标记率为(95.54±0.85)%,其符合一次静脉给药的药代动力学二室模型,分布半衰期T1/2á=(2.97±0.48)min,消除半衰期T1/2a=(52.49±19.49)min,血液总清除速率(CL)=(14 314.29.±8445.79)ml/h.心、肝、肺时间-放射性曲线显示[99Tcm(N)(PNP5)(DBODC)]+肝摄取在初始时明显高于心肌,但肝内放射性清除迅速,在注射30 min后,肝内放射性已低于心肌放射性,而99Tcm-MIBI肝摄取在180 min内均高于心肌.[99Tcm(N)(PNT5)(DBODC)]+的心/肝比值在注射后30～180 min均高于99Tcm-MIBI(t值为10.395～54.482,P均＜0.05).显像示在注射[99Tcm(N)(PNP5)(DBODC)]+后5～180 min均可获得清晰的心肌图像,肝内示踪剂迅速排入胆、肠系统,致使肝内放射性迅速减低,有利于减少对左室下壁的干扰.结论 [99Tcm(N)(PNP5)(DBODC)]+有望成为一种新的心肌灌注显像剂.     

Detection of inflammatory lymph nodes in rabbits by 99mTc-HIG lymphoscintigraphy

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and evaluation of inflammatory lymph nodes.     

Cystic disease of the liver studied by 99Tcm DISIDA and 99Tcm sulphur colloid imaging

Two patients with cystic disease of the liver have been studied with 99Tcm sulphur colloid and 99Tcm DISIDA scintigraphy and CT. One patient's cystic lesions are substantially enlarged as seen in 99Tcm sulphur colloid scintigrams performed at 10 year intervals. Another patient's scintigraphic studies performed at 5 year intervals demonstrated no significant progression in the size of the cysts in the liver. The 99Tcm DISIDA scintigram of each patient demonstrated no radiotracer filled-in in the cystic lesions (photon deficient areas on 99Tcm sulphur colloid scan). This finding may be used to differentiate cystic disease of the liver from hepatoma, in which usually DISIDA filled-in the defects seen on the 99Tcm sulphur colloid scintigram.     

99Tcm-c-myc mRNA反义肽核酸荷结肠癌裸鼠显像

目的 制备99Tcm-c-myc mRNA反义肽核酸(PNA)显像探针,通过反义显像研究99Tcm-c-myc mRNA反义PNA早期诊断结肠癌的可行性.方法 利用化学合成法在c-myc mRNA反义PNA片段的5'端连上4个氨基酸[G-(D)-A-G-G]和1个氨基丁酸(Aba),再利用配体交换法对c-myc mRNA反义PNA行99Tcm标记.并用同样的方法制备99Tcm-c-myc mRNA无义PNA.进行人结肠癌LS174-T荷瘤裸小鼠显像.采用SAS 6.12软件进行统计学处理.结果 99Tcm-c-myc mRNA反义PNA 6h内标记率＞95%.血清孵育5h后标记率为91.1%.无义PNA的标记率与反义PNA基本一致.1h时反义组荷瘤裸鼠右后肢肿瘤部位可清晰显影,4h内未见明显变化.无义组肿瘤部位始终未见明显放射性摄取.注射99Tcm-c-myc mRN反义PNA 1h后,反义组与无义组肿瘤与对侧组织的放射性(T/N)比值分别为5.06±1.35和1.53±0.30,差异有统计学意义(t=4.47, P=0.04).结论 99Tcm-c-myc mRNA反义PNA可在荷瘤裸鼠活体内与高表达c-myc基因的人结肠癌LS174-T肿瘤组织特异结合,在肿瘤反义显像中有潜在的应用价值.     

Myocardial kinetics of 99Tcm hexakis-(2-methoxy-isobutyl-isonitrile) (HMIBI) in patients with coronary heart disease: a comparative study versus 201Tl with SPECT

In 15 patients with coronary heart disease, 74 MBq 201Tl (A) and 240 MBq 99Tcm HMIBI (B) were injected during exercise on separate days and SPECT imaging was applied. In (B) a consecutive second injection was given with an identical dose 3 h later (at rest) and net rest distribution was obtained from a subtraction technique. From polar, target-like ROIs, data were computed to compare regional vitality, wash-out and wash-out corrected redistribution. Myocardial wash-out, in contrast to 201Tl, was found to be 20% for 99Tcm independent of the regional myocardial state. Since no considerable redistribution occurred, myocardial distribution of 99Tcm HMIBI remained rather constant for 3 h, resulting in a maximum myocardium to lung ration of about 5. After the second injection, redistribution revealed the same results as in the 201Tl targets. From regional exercise to rest ratios a 'perfusion reserve' was determined which was 2.1 in normal and 1.3 in myocardial areas with defects. Myocardial defect uptake and defect size were nearly identical, yielding agreement in 97% of the myocardial segments. We conclude that 99Tcm HMIBI is a most powerful myocardial imaging agent. The final routine protocol, however, is as yet not established.     

99Tcm-MDP uptake by lymph nodes following tracer infiltration: clinical and laboratory evaluation

Uptake of bone scanning agents in non-osseous sites has been described in a variety of pathologic conditions including tumor metastases. We have seen several patients in which such uptake was proximal and ipsilateral to the injection site of 99Tcm-methylene diphosphonate, apparently in normal lymph nodes. To further investigate this phenomenon, it was studied in a rat model. Activity in popliteal nodes ipsilateral to the injection site was over 60-fold greater in the animals that received subcutaneous (s.q.) footpad injection compared to femoral IV injection. Ipsilateral popliteal node activity in the s.q. group was 159 times that of contralateral popliteal nodes, with an ipsilateral node to liver ratio of 184:1. In summary, dramatically increased uptake of 99Tcm-MDP in normal lymph nodes ipsilateral and proximal to an extravasated injection has been demonstrated. An awareness of this phenomenon in the clinical setting can avoid confusion with pathologic forms of soft tissue uptake.