99mTc标记depreotide的实验研究

目的:采用直接标记法将99mTc标记dep-reotide,筛选depreotide的最佳标记条件,建立一种简便可靠的99mTc-depreotide制备方法.方法:采用直接标记99mTc的方法,在不同的pH值(5.0、6.0和7.0)缓冲溶液和不同的环境温度(15℃、37℃和50℃)条件下,对depreotide进行标记,以纸层析法测定计算标记率并通过比较分析筛选出最佳标记条件.结果:1)同一温度条件下,pH6.0实验组标记率高于pH5.0和pH7.0两实验组.在15℃条件下,PH5.0组和pH6.0纽的标记率统计分析结果为t=9.232,P<0.001;pH6.0组与pH7.0组的t=9.533,P<0.001;在37℃条件下,pH5.0组与PH6.0组的t=4.121,P<0.01;pH7.0组与pH6.0组的t=6.207,P<0.001.2)随着反应温度由15℃逐渐升高到50℃,各pH实验组的标记率不同程度地下降.结论:99mTc直接标记depreotide,在低温(<15℃)和弱酸性环境下,肿瘤标志的标记率高,稳定性好.     

Breast Cancer 99mTc Sm3 Radioimmunoscintigraphy

^99mTc SM3 radioimmunoscintigraphy is combined with kinetic analysis and probability mapping using a change detection algorithm to investigate axillary node involvement before primary surgery in patients with breast cancer. Whereas planar imaging was unsuccessful, axillary node involvement was correctly determined in 11 out of 13 patients 6 out of 7 true negatives and 5 out of 6 true positives down to 0.35 grams. A prospective study is underway     

Contamination Incidents Resulting from the Use of a 99Mo-99mTc Generator

A contamination incident involving the spread of “”Mo from a ^89mTc generator supplied by the Australian Atomic Energy Commission is reported. The circumstances of the ‘spill’ and the activity involved are described. Suggestions are made, both to users and to the A.A.E.C., as to the steps that could be taken to diminish the risk of such an incident.     

Variations in 99mTc Brain Scans Reported as Normal

The average number of brain scans performed in this unit per month is 50. Of these 7H% are reported as normal. A survey has been made of a series of adult Technetium-99m brain scans reported as normal. An attempt lias been made to assess the variations in the normal pattern. The effect of potassium perchlorate in blocking the uptake of 99^mTc by the thyroid gland and choroid plexus is evaluated.     

Somatostatin with 99mTc and biodistribution studies in rats

Somatostatin (SST) is a short-lived peptide hormone that regulates the endocrine system. The main use of the derivatives of SST is to diagnose diseases related to growth hormone and to use against some forms of cancer that involve growth hormone. Also, SST suppresses gastric acid secretion, gallbladder contractions, and pancreatic enzyme secretion. In this study, two different bifunctional chelating agents were used to examine the changes in the biologic half-life of SST. For this purpose, first D-penicillamine (D-PA) and diethylene triaminepentaacetic acid (DTPA) were used to label SST with (99m)Tc and then radiopharmaceutical potential of three (99m)Tc-labeled complexes, (99m)Tc-D-PA, (99m)Tc-D-PA-SST, and (99m)Tc-DTPA-SST, were compared with each other. Quality control for each labeled complex was established by using radiochromatographic methods. The radiolabeled complexes maintained their stabilities for 5 hours. Then, biodistribution studies were performed on Albino Wistar rats independently for three complexes. The results demonstrated that (99m)Tc-D-PA-SST exhibited long-term uptake in organs, and its clearance took longer than the (99m)Tc-DTPA-SST complex.     

The insensitivity of 99mTc pertechnetate imaging for Kaposi's sarcoma

A total of 13 technetium 99m (99mTc) pertechnetate image studies were performed on 7 patients with a histologic diagnosis of Kaposi's sarcoma. Five patients with peripheral edema had diffusely increased radionuclide activity in the same areas. The two patients without edema had normal radionuclide images. The primary cutaneous lesions were only identified in one of the patients. These findings suggest that previously reported "occult metastasis" are probably due to peripheral edema in most patients; therefore, the radionuclide study has a much lower sensitivity than has been previously reported.     

STUDIES OF ~(99m)Tc LABELLED MONOCLONAL ANTIBODY 3H11

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Breast cancer takes up 99mTc bombesin. A preliminary report

BACKGROUND: Several tumors including lung, prostate, ovarian, colon, and exocrine pancreatic cancer show receptors for the amphibian neurotransmitter and growth factor bombesin (BN) and its mammalian counterparts gastrin-releasing peptide and neuromedin B. Also breast cancer has been reported to show such receptors: the presence of BN receptors in primary breast cancer has been demonstrated on cultured cells and by autoradiography on breast tissue samples. Authors who have studied BN receptors in breast cancer do not agree on their frequency in primary cancer, but indicate that 100% of metastatic breast cancers show such receptors. METHODS: We examined three primary breast cancer patients with 99mTc BN and 99mTc sestamibi one week before surgery. One of them showed axillary node invasion. The same acquisition technique was used for breast and chest imaging with both radiopharmaceuticals, whereas total body images were acquired only with 99mTc BN. Also the administered radioactivity was different: 20 mCi of 99mTc sestamibi and 5-8 mCi of 99mTc BN. Dynamic images were acquired for 20 mins after iv injection with the patient in ventral decubitus and the gamma camera positioned in a lateral view, as is generally done in Khakhali's prone scintimammography. Anterior chest images were acquired for 30 mins. Prone scintimammography was performed one hour after administration of both tracers. ROIs were drawn on tumors and surrounding breast with the same technique in order to calculate the tumor to breast ratio (T/B). In addition, total body scan was performed one hour and three hours after 99mTc BN administration. All three patients underwent breast conserving surgery with lymphadenectomy. Postoperative pathologic assessment showed the following T and N stages in the three patients: T1bN0, T1c-N0, and T1cN1. RESULTS: All three cancers were imaged with both tracers. The T/B of 99mTc BN was always higher than that of 99mTc sestamibi. Chest uptake was always much higher with 99mTc sestamibi than with 99mTc BN. Comparison between 99mTc BN and 99mTc sestamibi images gave other intriguing results: in the N1 patient both tracers clearly imaged the invaded node, but on the 99mTc BM image the primary tumor was larger than on the 99mTc sestamibi image and the node was smaller. It is known that 99mTc BN is not taken up by vessels and inflammatory tissue. The time activity curves of the two tracers were significantly different in all patients, with an increase in 99mTc BN uptake in the first three to five minutes, followed by a less sharp uprise of the curve, quite similar to a plateau. CONCLUSIONS: Our first impression is that 99mTc BN is a useful breast cancer seeking agent and very promising for lymph node staging.     

Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with 99mTc

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM.     

Accumulation of 99mTc methylene diphosphonate in malignant pleural and ascitic effusion

Increased accumulation of radioactivity was observed in malignant pleural and ascitic effusion as to a patient with stomach cancer and in malignant pleural effusions as to 2 patients (1 with breast cancer and another with lung cancer) during the performance of routine whole-body bone scans with 99mTc methylene diphosphonate. This finding should strongly suggest malignancy.     

Dual-isotope lymphoscintigraphy using albumin nanocolloid differentially labeled with 111In and 99mTc

The aim of this study was to develop and evaluate ¹¹¹In- and ^99mTc-labeled derivatives of albumin nanocolloid (NC) for dual-label lymphoscintigraphy to allow simultaneous comparison of lymphatic flow from different tissue planes draining a tumour bed for accurate identification of sentinel lymph nodes (SLN). Using the chelator, p-isothiocyanatobenzyl-1,4,7,10-tetraazacyclododecane-1,4,7,10- tetraacetic acid (DOTA), ¹¹¹In-DOTA-NC and ^99mTc-DOTA-NC were compared in vitro with respect to stability of labeling, colloidal status and particle size, then in vivo by measuring their clearance rates from a subcutaneous injection depot. ¹¹¹In-DOTA-NC and ^99mTc-DOTA-NC were indistinguishable on the basis of in vitro criteria. Their in vivo clearance rates, however, were disparate (0.0015 to 0.075 min^-1 for ¹¹¹In and 0.0072 to 0.067 min^-1 for ^99mTc), ¹¹¹In being faster in three studies and markedly slower in three. This demonstrates that even when dual-labeled radiotracers behave identically in vitro, they will not necessarily do so in vivo. Further work is needed to develop dual-labeled NC.     

99m Tc-tetrofosmin SPECT显像在鉴别乳腺包块良恶性病变中的价值

目的 :探讨99mTc tetrofosmin乳腺扫描在鉴别可扪及的乳腺包块良恶性病变中的价值。方法 :采用前瞻性同步盲法。 2 0 0 0年 6月～ 2 0 0 1年 1 2月在我院临床发现乳腺包块的 1 0 1例患者接受SPECT乳腺扫描 ,并与针吸细胞学检察 ,乳腺X片和乳房彩色多谱勒检查进行了对比。全部病例进行了手术 ,以术后病理结果为标准。以四格表进行评价分析。结果 :99mTc tetrofosmin在对可扪及的乳腺包块性质进行鉴别诊断时 ,特异性 84.0 % ,敏感性 86 .3 % ,准确性 85 .1 % ,阳性预测值 84.6 % ,阴性预测值 85 .7%。结论 :99mTc tetrofosmin在对可扪及的乳腺包块进行良恶性质的鉴别时 ,不失为一种方便且较为准确的方法     

Quantitative Analysis of Tight Junctions and the Uptake of 99mTc in Human Gliomas

The structural dimensions of capillary tight junctions and the uptake of ^99mTc pertechnetate in human gliomas were studied. Quantitative analysis revealed a correlation between the uptake of radionuclides and the length of endothelial tight junctions. It is suggested that brain scintigraphy might be used for the selection of malignant brain tumors with altered tight junctions which might be accessible to chemotherapy with water-soluble agents.     

99mTc-MIBI显像在原发性甲状旁腺功能亢进定位诊断中的应用价值

目的:评价99mTc-甲氧基异丁基异腈(99mTc-MIBI)显像在原发性甲状旁腺功能亢进症(PHPT) 定位诊断中的临床应用价值。方法:回顾性分析57例疑似PHPT患者99mTc-MIBI显像、血清PTH测定及B超检查结果,以术后病理为金标准,对99mTc-MIBI双时相显像、血清PTH测定及B超检查三种诊断方法的灵敏度、特异度、准确度进行比较和评价。结果:术后病理证实,57例患者99mTc-MIBI显像与血清PTH测定两种诊断方法比较,灵敏度、特异度、准确度分别为91.49%（80.85%）、50.00%（80.00%）、84.42%（80.70%）;99mTc-MIBI显像与B超检查两种诊断方法比较,灵敏度、特异度、准确度分别为91.49%（76.60%）、50.00%（70.00%）、84.21%（75.44%）。结论:99mTc-MIBI显像对PHPT定位诊断的灵敏度、准确度都高于血清PTH测定及B超检查结果,但特异性较低。99mTc-MIBI显像联合血清PTH测定及B超可以提高PHPT的诊断准确性,具有更高的临床应用价值。     

Soft tissue uptake on 99mTc methylene diphosphonate bone scan imaging: Pictorial review

^99mTechnetium methylene diphosphonate (MDP) bone isotope may accumulate in many extra‐osseous sites due to a variety of both benign and malignant conditions. This finding on a bone scan can be crucial to the diagnosis and may not be apparent in other imaging or the clinical evaluation of the patient. We present a pictorial review sampling some of the many causes of extra‐osseous ^99mTc MDP accumulation.     

Histomorphometric changes of osteosarcoma after chemotherapy. Correlation with 99mTc methylene diphosphonate functional imaging

An investigation to correlate histologic changes in 12 osteosarcoma specimens from patients undergoing chemotherapy was performed using functional images of regional 99mTc methylene diphosphonate (MDP) plasma clearance rates assessed from dynamic bone scintigraphies taken during chemotherapy. Residual tumor cell viability was determined by microscopic examination of multiple thin sections from surgical specimens and quantitated by histomorphometry. Regions that showed decreases in 99mTc MDP plasma clearance of more than 20% were associated with areas of necrotic tumor, and regions that showed absent decline or increasing clearance rates were associated with high residual cell viability and incomplete response to chemotherapy. Therefore, functional bone scintigraphy allows an objective presurgical assessment of tumor response to chemotherapy.     

Lanreotide labeled with 99mTc: preparation,preclinical testing and comparison with (111)In-DTPA-octreotide

Somatostatin receptors are known to be present at a high density in a large number of tumors while (111)In-DTPA-octreotide has been routinely used in oncology for imaging somatostatin receptor-positive tumors and metastases. Lanreotide is another somatostatin receptor-specific peptide, shown to be effective in controlling the growth of some human tumors. The aim of this study was to label lanreotide with 99mTc by a direct labeling method and to evaluate the distribution and elimination characteristics of the labeled agent in rats. (111)In-octreotide was used as the reference radiopharmaceutical. For both radiolabeled-peptides the activity in blood and most organs decreased relatively rapidly with time. On the other hand, 99mTc-lanreotide was excreted mainly by the gastrointestinal tract to feces while (111)In-DTPA-octreotide was eliminated mostly into urine. The rat liver perfusion experiments showed that bile clearance of 99mTc-lanreotide was about three-order times higher than for (111)In-DTPA-octreotide. Analysis of the elimination mechanisms of 99mTc-lanreotide and (111)In-DTPA-octreotide in the perfused rat kidney confirmed that both peptides were eliminated mostly by glomerular filtration. Different protein binding of the agents ((111)In-DTPA-octreotide was only weakly bound, whereas 99mTc-lanreotide was strongly bound to proteins) resulted in substantially lower renal clearance of 99mTc-lanreotide when compared with (111)In-DTPA-octreotide. The results indicated that 99mTc-lanreotide could be of value for the scintigraphic imaging of specific tumors.