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PubMed1988

[Quantitative renal scintigraphy with technetium-labelled dimercaptosuccinic acid in children].

Separate measurement of renal function is essential in children with urinary tract disease. This can be done satisfactorily by means of kidney scintigraphy with technetium 99m-labelled dimercaptosuccinic acid. A retrospective study of the records of 415 children, which comprised renal function tests, radiology and scintigraphy, confirmed the value of the radioisotope technique. Graphs of height, kidney uptake and kidney uptake density in relation to age were established, showing highly significant correlations with renal function tests and intravenous urography results, but many dissociations were encountered. Separate renal function evaluation by radioisotope scintigraphy seems to be more reliable than evaluation extrapolated from measurement of the cortical areas at intravenous urography. In vesico-ureteral reflux scintigraphy makes it possible to detect reflux nephropathy at an earlier stage than with other methods.

Age Factors↗
PubMed1979

Technetium 99m bone imaging in the evaluation of cancer of the maxillofacial region.

Technetium 99m bone images were obtained from five patients with mandibular gingival carcinoma and six patients with maxillary sinus carcinoma. Ten to 15 mCi of 99mTc-polyphosphate was administered intravenously, and imaging was performed three hours after injection. The anterior and lateral views of the maxillofacial skeleton were obtained with a gamma camera. Resultant gamma camera images were compared with the radiographic skeletal survey. 99mTc bone survey is a safe and simple diagnostic technique that can demonstrate abnormality of the bone with greater sensitivity than routine radiographs.

Adult↗
PubMed1988

Differential effect of aluminum on the blood-brain barrier transport of peptides, technetium and albumin.

Aluminum is a neurotoxin capable of altering membrane structure and function. We investigated whether aluminum also can affect saturable transport across membranes using the blood-brain barrier as our model. Mice were given i.p. or i.v. aluminum (up to 100 mg/kg) as the chloride salt and the disappearance from the brain of several centrally administered substances was measured. We found that aluminum rapidly and profoundly inhibited the saturable system that transports the small, N-tyrosinated peptides Tyr-MIF-1 and the enkephalins from the brain to the blood by acting as a noncompetitive inhibitor. In contrast, the disappearance from the brain of technetium pertechnetate (a substance also transported out of the brain by a different saturable system), albumin or D-Tyr-MIF-1 (a stereoisomer of Tyr-MIF-1 that was confirmed not to be transported by the carrier system) was not affected by aluminum. Aluminum also did not alter either the saturable or nonsaturable component of the uptake of Tyr-MIF-1 by erythrocytes. These findings suggest that one mechanism by which aluminum may induce neurotoxicity is by selective alteration of the transport systems of the blood-brain barrier.

Albumins↗
PubMed1989

Forearm blood flow measurements using technetium-99m human serum albumin following brachial arteriotomy.

A simple, low cost method for measuring forearm blood flow during reactive hyperemia has been developed. Subjects are seated with hands and forearms over a large field-of-view gamma camera. Blood pressure cuffs inflated above the elbows isolate the blood in the forearms and hands and induce a hyperemic response. The remaining blood pool is labeled with technetium. The rate of increase of activity following release of the cuffs is measured from the gradient of time-activity curves and is calibrated for flow by counting a venous blood sample. The technique has been applied to a group of normal controls and to symptomatic and asymptomatic patients following right brachial arteriotomy. Forearm blood flow in normal subjects was 32.9 +/- 6.4 ml/100 ml/min and for subjects with occlusion of the brachial artery was 6.4 +/- 2.1 ml/100 ml/min. The method is simple, widely available, and reproducible. The good signal to noise ratio allows it to be used in cases of very low flow either as an aid to diagnosis or to measure treatment response.

Adult↗
PubMed1987

Suppression by perchlorate of technetium-99m and iodine-123 secretion in milk of lactating goats.

Lactating goats were infused with either technetium-99m (99mTc) or iodine-123 (123I) together with chlorine-36 (36Cl) through an indwelling catheter previously placed in an external pudic mammary artery. The radioisotope infusions were repeated together with 100 mg of sodium perchlorate. There was a rapid transfer of 99mTc and 123I into milk, reaching a peak concentration 30 min after a 15-min infusion. The fractional secretion of 99mTc and 123I in milk was reduced by 70%-80% and 60%-66%, respectively, by perchlorate. The fractional secretion of 36Cl was not affected by perchlorate, and the shape of the 36Cl secretion curve differed from those of 99mTc and 123I, which were similar. It is probable, therefore, that the latter nuclides were secreted by a transport route different from that of chloride. Available data describing the secretion of 99mTc in human milk after pertechnetate administration was reviewed, and it was concluded that perchlorate pretreatment significantly reduced the secretion of 99mTc in human breast milk.

Animals↗
PubMed1987

Technetium-99m bis (aminoethanethiol) complexes with amine sidechains--potential brain perfusion imaging agents for SPECT.

In an effort to develop new clinically useful technetium-99m bis(aminoethanethiol) ([99mTc]BAT) complexes for the evaluation of regional cerebral perfusion, two new BAT ligands containing amines in the sidechain were synthesized and subsequently complexed with 99mTc to yield the target complexes: [99mTc]DEA and [99mTc]TMPDA. Each complex was obtained as mixtures of two isomers, syn and anti, which were separated chromatographically. In biodistribution studies, both isomers of [99mTc]TMPDA showed little uptake in the brain. In contrast, the brain uptake values at 2 and 15 min for [99mTc]DEA-anti were 0.99 and 0.26, whereas, the corresponding values for DEA-syn were 2.27, 0.64% dose/organ, respectively. Autoradiographic studies (in rats) using both isomers of [99mTc]DEA show a fixed regional distribution and a higher concentration of radioactivity in the gray matter relative to the white matter. Planar imaging using [99mTc]DEA-syn clearly demonstrates localization of the complex in the brain with a T 1/2 of 41 min, suggesting some potential for use with single photon emission computed tomography.

Animals↗
PubMed1979

[Scintiscanning with technetium-99m pertechnetate in the diagnosis of Meckel's diverticulum].

Personal experience with technetium99m pertecnetate scanning in the diagnosis of Meckel's diverticulum is reported. The data reported indicate that the scan can be considered positive when the lower right quadrant of the abdomen shows a definite accumulation of radioactivity. Of 12 children examined, 4 responses were positive. These 4 patients were submitted to surgery and this confirmed the presence of Meckel's diverticulum containing gastric mucosa, and of an ulcer in the adjacent ileal mucosa. After discussing the clinical value of the investigation and having examined the problem of false positives and false negatives, in relation to reported data, it is concluded that scanning with technetium has a vital role to play in the diagnosis of haemorrhage due to Meckel's diverticulum.

Adolescent↗
PubMed1987

The 99m technetium labeling effect on bacterial surface properties.

The present study was undertaken to determine whether labeling Pseudomonas aeruginosa with 99m Technetium would modify some of the bacterial physicochemical surface properties which play an important role in the interaction between bacteria and eukaryotic cells. No significant difference in electrophoretic mobility or distribution of cationized ferritin on the cell surface was observed between labeled and unlabeled bacteria. Also, the 99m Tc labeling process did not modify bacterial hydrophobicity or adhesiveness to human buccal epithelial cells. It is concluded that bacterial labeling with 99m Tc can be accepted as a useful method for biological research.

Bacterial Adhesion↗
PubMed1979

Acute gastrointestinal bleeding detected with abdominal scintigraphy using technetium-99m-labeled albumin.

In 24 patients admitted with gastrointestinal bleeding 36 scintigraphic studies of the abdomen were performed after intravenous injection of technetium-99m-labeled albumin. In 12 patients bleeding from the esophagus, stomach, duodenum, biliary tract, or colon was visualized. In the other 12 patients, in whom the bleeding seemed to have subsided, the investigation showed no scintigraphic signs of hemorrhage. Scintigraphy was also negative in five controls who had no bleeding. The method is non-invasive and easy to perform. Our study suggests that it is reliable, but a controlled trial is necessary to evaluate the diagnostic value of the method.

Acute Disease↗
PubMed1988

[Thallium-technetium scintigraphy for presurgical localization of parathyroid adenomas and hyperplasia].

The purpose of this study was to assess the value of parathyroid Thallium 201-Technetium 99m scintigraphy in 45 patients with hyperplasia or parathyroid adenomas with or without associated thyroid abnormalities. The prevalence of parathyroid abnormalities found during examination was 42/45: 36 adenomas (35 patients) and 16 hyperplasias (7 patients). Seventeen patients (38%) had thyroid abnormalities. The sensitivity and specificity of the three image analysing methods (visual analysis, simple subtraction, sophisticated subtraction) were determined by assessing answers given by 3 observers. The population was divided into 6 groups: adenomas and hyperplasias with (group I, n = 42) or without (group II, n = 25) thyroid abnormalities, adenomas alone with (group III, n = 35) or without thyroid abnormalities (group IV, n = 22), hyperplasias alone with (group V, n = 7) or without thyroid abnormalities (group VI, n = 5). The highest overall sensitivity was obtained, whichever the group, by applying the sophisticated image subtraction technique; for any given method, the best results were observed in the group comprising adenomas alone, especially without associated thyroid abnormalities. On the other hand, in the groups comprising hyperplasias alone, sensitivity was low. This leads us to conclude that, together with ultrasonography, parathyroid scintigraphy is currently the best preoperative technique for localizing parathyroid adenomas, even in the presence of associated thyroid abnormalities. However this must be carried out in conjunction with a sophisticated image subtraction technique.

Adenoma↗
PubMed1988

Hexakis(carbomethoxyisopropylisonitrile) technetium(I), a new myocardial perfusion imaging agent: binding characteristics in cultured chick heart cells.

Cellular kinetics and binding characteristics of hexakis(carbomethoxyisopropylisonitrile) technetium(I) (Tc-CPI), a new cationic, highly lipophilic myocardial perfusion imaging agent, were evaluated in chick embryo heart cells grown in monolayer culture. Myocytes showed uptake of Tc-CPI to a plateau level with a half-time (t1/2) of 4.1 +/- 0.7 min (mean +/- s.e.m.; n = 6); t1/2 appeared independent of extracellular Tc-CPI concentration. Plateau level Tc-CPI uptakes (10(-16) to 10(-11) mole Tc-CPI/mg cell protein) were a linear function of extracellular Tc-CPI concentration (range: 10(-13)M to 10(-8)M, respectively). Tracer 99mTc-CPI uptake (binding) was not competitively displaced by carrier 99Tc-CPI. Uptake was temperature-sensitive; however, several inhibitors of cationic membrane transport (ouabain, amiloride, bumetanide, and verapamil) showed no significant effect. Extreme alkalinization of external load solution (pHo approximately 8.5) partially inhibited Tc-CPI uptake; however, intracellular pH changes showed no effect. Washout from contractile preparations could be described by a two component system: a fast component (myocytes) with a t1/2 approximately 4.5 min and a slow component (fibroblasts) with a t1/2 approximately 40 min. Cell fractionation experiments showed most of the activity to be associated with the cell membrane fraction. The data do not demonstrate a specific mechanism for uptake of Tc-CPI; however, results suggest binding to myocytes in a manner proportional to the delivery of the complex to the extracellular spaces. Such properties would be desirable for a myocardial perfusion imaging agent.

Animals↗
PubMed1988

Microautoradiographic study of technetium-99m colloid uptake by the rat liver.

A new microautoradiographic technique was developed to study the distribution of 99mTc-labeled radiopharmaceuticals. Using a thick emulsion, it is possible to get microscopically visible tracks of internal conversion and Auger electrons. The liver uptake of microscopic particles has been thought to occur in Kupffer cells but no direct evidence has been provided for technetium colloids. Using this method, 99mTc-labeled colloids were clearly identified in Kupffer cells in the sinusoidal areas of liver. "Track" microautoradiography using a thick emulsion layer may be used on any frozen tissue sections and may provide an important tool to assess the biodistribution of 99mTc radiopharmaceuticals.

Animals↗
PubMed1977

Acute myocardial infarction: clinical application of technetium 99m stannous pyrophosphate infarct scintigraphy.

Acute myocardial infarction is being recognized as a spectrum of clinical subsets. This appreciation has been brought about to a large degree by the development of several new tools that can be applied clinically to aid in evaluation of patients with acute infarction, and in some cases to provide short and long-term prognostic information. In the realm of noninvasive methods, several tests utilizing radiopharmaceuticals and scintillation cameras have emerged and are rapidly becoming reliable diagnostic parameters in patients with coronary disease and infarction. Technetium 99m (stannous) pyrophosphate (TcPYP) scintigraphy, one of the first of these techniques to find clinical use, has been shown to be an accurate indicator of acute transmural myocardial infarction and provides added sensitivity and specificity to the diagnosis. Increased diagnostic accuracy, the dimension of visible localization and the potential for infarct sizing promise physicians better understanding of a patient's clinical presentation and a more rational approach to management.

Acute Disease↗
PubMedDate not supplied

Long-term follow-up of technetium articular index in rheumatoid arthritis patients during oral chrysotherapy: evidence of paradoxical behaviour.

The Technetium Articular Index (TcAI) is regarded as a parameter of local inflammation in rheumatoid arthritis (RA). We studied TcAI behaviour during 1-year chrysotherapy in a group of fifteen RA patients. In non-responders TcAI showed a gradual decrease up to the 6th month and a return to baseline values within the second semester of the follow-up; conversely, in response patients TcAI remained unchanged during the entire period of the study, thus showing a paradoxical behaviour probably depending on the recovery of normal physical ability and articular activity.

Administration, Oral↗
PubMed1986

[Hemorrhagic Meckel's diverticulum. The place of abdominal scintigraphy with technetium 99m. Apropos of a case with gastric and pancreatic heterotopia].

A 12 year old child presented with a hemorrhagic Meckel's diverticulum, gastric heterotopia without identifiable ulceration and a totally aberrant pancreas. The diagnostic value of 99m-technetium abdominal scintigraphy in patients with Meckel's diverticula and gastric heterotopia, as well as the limits of this investigation, are discussed.

Child↗
PubMed1986

[Experimental arterial microsutures. Evaluation of the risks of thrombosis using technetium 99-labeled heparin].

Following demonstration of a method of assay of circulation heparin by measurement of radioactivity after labelling with 99 m technetium, the technique was used to study effects of arterial microsuture on metabolism of heparin injected postoperatively. Results of a study involving rat aorta showed that local binding was maximum during the first half-hour and that abnormal consumption of heparin continued during the 6 hours following operation. These finding suggest that a risk of thrombosis probably persists throughout this postoperative period.

Animals↗
PubMed1987

Technetium 99m labelled heparin: pharmacokinetics and tissue distribution in rats after vascular surgery.

Pharmacokinetics of technetium 99m (99mTc) labelled heparin was studied after I.V. infusion (70 IU/kg) in normal rats and in a group of animals just after aortic longitudinal incision and suture. Anticoagulant activity measurements and radioactivity were compared on the same plasma samples. The pharmacokinetic decay of 99mTc-heparin followed a bi-exponential pattern. Half-lives (T1, T2) were significantly shortened after surgery using both techniques. Liver accumulation of labelled heparin was decreased in "sutured" rats and a high uptake of 99mTc-heparin was found on the operated area of the aorta.

Animals↗

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