Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TECHNETIUM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources
PubMed1990

Correlations between uptake of technetium, calcium, phosphate, and mineralization in rat tibial bone repair.

Technetium-99m-(99mTc) phosphates are extensively used for detection of bone formation and resorption. The present is a study of 99mTc incorporation during bone remodeling. Uptake of 99mTc-labeled phosphate was studied in an animal model of primary osteogenesis following tibial marrow injury and incorporation was correlated to that of calcium-47 (47Ca), phosphorus-32 (32P), and with matrix vesicle calcification. Isotope uptake on Day 6 in the whole bone was increased compared to controls. On this day, an increase in vesicular diameter and distance from the calcified front was previously observed. Technetium-99m-labeled phosphates were detected only in the organic phase. Phosphorus-32 and 47Ca were detected in both organic and inorganic phases. It is suggested that 99mTc serves as a specific marker to the anabolic phase of remodeling. Increased incorporation of 99mTc during bone healing indicates enhanced organic matrix formation and not calcification.

Animals↗
PubMed1990

Technetium-99m-human polyclonal IgG radiolabeled via the hydrazino nicotinamide derivative for imaging focal sites of infection in rats.

The biologic behavior of human polyclonal immunoglobulin (IgG) radiolabeled with technetium-99m (99mTc) by a novel method, via a nicotinyl hydrazine derivative, was evaluated in rats. Technetium-99m- and indium-111-IgG were co-administered to normal rats and biodistribution was determined at 2, 6, and 16 hr. The inflammation imaging properties of the two reagents were compared in rats with deep-thigh infection due to Escherichia coli. Blood clearance of both antibody preparations was well described by a bi-exponential function: (99mTc-IgG: t1/2 = 3.82 +/- 0.89 and 57.52 +/- 1.70 hr. 111In-IgG: 3.93 +/- 0.117 and 40.71 +/- 1.26 hr). Biodistributions in the solid organs were similar, however, small but statistically significant differences were detected: 99mTc-IgG greater than 111In-IgG in lung, liver, and spleen; 99mTc-IgG less than 111In-IgG in kidney and skeletal muscle (p less than 0.01). At all three imaging times, target-to-background ratio and percent residual activity for the two compounds were remarkably similar. These studies establish that human polyclonal IgG labeled with 99mTc via a nicotinyl hydrazine modified intermediate is equivalent to 111In-IgG for imaging focal sites of infection in experimental animals.

Animals↗
PubMed1979

Evaluation of bone-marrow scanning with technetium-99m sulfur colloid in pediatric oncology.

Eighty-six technetium-99m sulfur colloid (Tc-SC) bone-marrow scans in 56 pediatric oncology patients were reviewed. The distribution of the sulfur colloid was similar to that in adult bone marrow in normal children older than 10 yr, and involved progressively more marrow of the extremities in normal children under 10 years of age. After irradiation or chemotherapy there was an extension of the Tc-SC to peripheral marrow sites. There was also diminished uptake of the tracer in sites corresponding to irradiated areas. In most patients there was recovery of these defects by 6 mo after completion of therapy. Tumor replacement of the marrow was reflected in the scans, and the extent of the scan defect paralleled the course of the disease. In four patients, despite normal bone scans and radiographs, marrow-scan abnormalities due to tumor replacement were present and confirmed by needle aspiration and/or biopsy. In two other patients, the marrow-scan abnormality preceded radiographic and histologic evidence of tumor metastasis. Two patients who responded clinically showed persistent defects; biopsy in one revealed fibrosis. Technetium-99m sulfur colloid bone-marrow scanning appears to be a sensitive monitor of marrow alteration caused by metastases, irradiation damage, or tissue fibrosis in children receiving treatment for cancer.

Adolescent↗
PubMed1989

Technetium-99m hexakis 2-methoxyisobutyl isonitrile: human biodistribution, dosimetry, safety, and preliminary comparison to thallium-201 for myocardial perfusion imaging.

The biodistribution, dosimetry, and safety of a new myocardial imaging agent, 99mTc-hexakis-2-methoxyisobutyl isonitrile (HEXAMIBI), was evaluated in 17 normal volunteers at rest and exercise (Phase I studies). Technetium-99m HEXAMIBI clears rapidly from the blood with good myocardial uptake and favorable myocardial-to-background ratios for myocardial imaging. Dosimetry allows for administration of up to 30 mCi (1, 110 Bq) of [99mTc]HEXAMIBI. The myocardial images were of good quality and appeared less granular with sharper myocardial walls compared to 201T1 images. The clinical efficacy of [99mTc]HEXAMIBI planar stress and rest imaging was evaluated in a multicenter Phase II clinical trial involving 38 patients. Of 36 patients with significant coronary artery disease, 35 patients (97%) had abnormal 201T1 stress images, and 32 (89%) had abnormal [99mTc]HEXAMIBI stress images (P = N.S.). Technetium-99m HEXAMIBI images correlated in 31/35 patients (86%) who had either scar or ischemia on 201T1 images. By segmental myocardial analysis, exact concordance was obtained in 463/570 myocardial segments (81%). This multicenter Phase I and II study indicates that planar [99mTc]HEXAMIBI stress imaging is safe and compares well with 201T1 stress imaging for detection of coronary artery disease.

Adult↗
PubMed1989

Technetium-99m (V) DMSA uptake in amyloidosis.

Technetium-99m(V) DMSA scintigraphy was performed in two patients with pathologically confirmed amyloidosis associated with plasmacytoma. Significant uptake of the tracer was found in the deposition of amyloid. Technetium-99m(V) DMSA scintigraphy could be useful in determining the appropriate region of biopsy and in forecasting the prognosis of patient with plasmacytoma.

Aged↗
PubMed1989

Predictive value of the three-phase technetium bone scan in diagnosis of reflex sympathetic dystrophy syndrome.

Reflex sympathetic dystrophy syndrome (RSDS) is a painful and disabling problem, the diagnosis of which can be difficult to confirm by objective measures. The three-phase technetium bone scan (TPBS), with a combined sensitivity and specificity of greater than 90%, has been recommended for use in the diagnosis of RSDS. The purpose of this study was to determine the predictive value and usefulness of the TPBS in the diagnosis of RSDS and to discover how the predictive value might be influenced by demographic and medical factors (eg, duration of symptoms). A retrospective chart review was conducted of 119 patients who underwent a TPBS as part of a workup for unexplained limb pain. Twenty-five patients met the Kozin criteria for definite or probable RSDS. All patients were injected with technetium-99m methylene diphosphonate and scanned using established criteria. The three-hour delayed image demonstrated a sensitivity of 44%, a specificity of 92%, a positive predictive value of 61%, and a negative predictive value of 86%. The blood-flow and pool-imaging phases added no further sensitivity or specificity to that achieved by the uptake scan in patients with upper-extremity involvement. Blood-flow and pool-imaging did improve the predictive value of the TPBS in patients with involvement of the lower extremities. We conclude that a more cost-effective approach to diagnosis of upper-extremity RSDS is to use the uptake scan alone.

Adult↗
PubMed1989

Gastrointestinal transit of technetium-99m-labeled cellulose fiber and indium-111-labeled plastic particles.

We introduce two new nondigestible solid markers for gastrointestinal transit measurements. One is technetium-99m-labeled cellulose fiber [99mTc]CF, the other is indium-111-labeled plastic particles [111In]PP of 2- to 3-mm diameter. In six healthy male volunteers gastric emptying and small intestinal transit of the two markers were obtained simultaneously. Large intestinal transit of [111In]PP was also obtained. Technetium-99m CF had acceptable stability properties in the proximal gastrointestinal segments. Indium-111 PP was almost completely stable in all segments. Mean gastric emptying time was 1.13 +/- 0.24 hr (mean +/- s.d.) for [99mTc]CF and 1.94 +/- 0.78 hr for [111In]PP. The difference was significant (p less than 0.05). Mean small intestinal transit time was 3.85 +/- 0.61 hr (mean +/- s.d.) for [99mTc]CF and 4.03 +/- 0.34 hr for [111In]PP. The difference was not significant (p less than 0.5). Mean large intestinal transit time of [111In]PP was 23 +/- 11 hr (mean +/- s.d.). We also suggest a simple deconvolution principle for the interpretation of the small intestinal and the large intestinal transit data.

Adult↗
PubMed1989

Cerebral perfusion imaging with technetium-99m HM-PAO in brain death and severe central nervous system injury.

We performed 38 cerebral perfusion studies in 33 patients with brain death or with severe central nervous system injury using technetium-99m hexamethyl-propyleneamine oxime [( 99mTc]HM-PAO). Uptake by the cerebrum and/or cerebellium was present in all patients who were not clinically brain dead (ten studies) although the study was often abnormal. In those patients who were brain dead, 16/17 studies demonstrated no uptake in either the cerebrum or cerebellum. In patients suspected of brain death, but who had conditions interfering with the diagnosis the test demonstrated no uptake in 9/11 studies, confirming brain death. A radionuclide angiogram (RNA) of the head was also performed in 33/38 studies and showed complete agreement with the [99mTc]HM-PAO uptake, except in one case. We conclude that cerebral perfusion imaging with [99mTc]HM-PAO is a simple, noninvasive and reliable test to confirm brain death. By comparison with conventional technetium agents, [99mTc]HM-PAO is not dependent on the quality of the bolus injection, is easier to interpret and allows evaluation of posterior fossa blood flow.

Adolescent↗
PubMed1985

Technetium-99m NGA functional hepatic imaging: preliminary clinical experience.

Technetium-99m galactosyl-neoglycoalbumin ( [Tc]NGA) is a radiolabeled ligand to hepatic binding protein, a receptor which resides at the plasma membrane of hepatocytes. This receptor-binding radiopharmaceutical and its kinetic model provide a noninvasive method for the assessment of liver function. Eighteen patients were studied: seven with hepatoma, eight with liver metastases, four with cirrhosis (two had concurrent hepatoma and one chronic active hepatitis), and one patient with acute fulminant non-A, non-B hepatitis. Technetium-99m NGA liver imaging provided anatomic information of diagnostic quality comparable to that obtained with other routine imaging modalities, including computed tomography, angiography, ultrasound, and [Tc]sulfur colloid scintigraphy. Kinetic modeling of dynamic [Tc]NGA data produced estimates of standardized hepatic blood flow, Q (hepatic blood flow divided by total blood volume), and hepatic binding protein concentration, [HBP]. Clinical correlation was by classical Child-Turcotte criteria (CTC). Significant rank correlation was obtained between [HBP] estimates and CTC scores (rs = -0.72, p = 0.001). This correlation supports the hypothesis that [HBP] is a measure of functional hepatocyte mass. The combination of decreased Q and markedly reduced [HBP] may have prognostic significance; all three patients with this combination died of hepatic failure within 6 wk of imaging.

Adult↗
PubMed1979

Meckel's diverticulum. Vagaries of technetium scanning.

A case of a Meckel's diverticulum is described in a young man presenting with abdominal pain and gastrointestinal bleeding. Methods of arriving at the diagnosis preoperatively are reviewed. A false-negative as well as a true-positive small bowel series and technetium scan were obtained in this case. The factors influencing technetium uptake by a Meckel's diverticulum are reviewed.

Abdomen↗
PubMed1987

In vivo inorganic chemistry of technetium cations.

Technetium-99m cations are of interest because of their potential use as myocardial perfusion imaging agents. These species can undergo in vivo reactions which markedly affect their biodistribution patterns. Four such cases of reactions are presented and discussed: (1) simple ligand substitution; (2) metal centered redox processes; (3) reactions of coordinated ligands; (4) outer sphere association reactions. New experimental techniques appropriate for investigating these reactions at the 10(-10) M concentration level of technetium encountered in vivo are also presented and discussed. The latter three classes of reactions are illustrated by examples taken from the recent literature and from unpublished data.

Animals↗
PubMed1987

Technetium-99m-labeled monoclonal antibody with preserved immunoreactivity and high in vivo stability.

Recent availability of monoclonal antibodies (MoAb) and their radiolabeling through the use of the bifunctional chelating agents (BCA) have become an alternative procedure for in vivo radioimmunodetection. Using a newly synthesized BCA, a p-carboxyethylphenylglyoxal-di(N-methylthiosemicarbazone) (CE-DTS), the coupling and technetium-99m (99mTc) labeling of monoclonal IgG against hCG were carried out. In the system presented, factors affecting stability and immunoreactivity were examined. Immunoreactivity of the original IgG (56C) was preserved by conjugating one CE-DTS molecule per molecule of IgG (56C) using the phosphorylazide method, however, 99mTc labeling pH affected the immunoreactivity and limited the 99mTc labeling reaction between pH 4.5 and 6.2. A screening of labeling conditions, such as pH, reaction time, and reducing agent system were then carried out. Technetium-99m-labeled IgG (56C), [99mTc]CE-DTS-IgG (56C), showed good stability upon incubation with mice sera and comparable mice biodistribution to that of indium-111 (111In) DTPA-IgG (56C). Thus, these results indicate the excellent potential of CE-DTS as a BCA for labeling MoAb with 99mTc.

Animals↗
PubMed1987

Development of nonreducible technetium-99m(III) cations as myocardial perfusion imaging agents: initial experience in humans.

A series of 15 nonreducible technetium-99m(III) complexes of formula tr-[99mTcL(Y)2]+ has been prepared by a general synthetic route based on reductive addition of Y to the technetium-99m (99mTc) intermediate [99mTcL(O)]+. In these complexes, selected for potential use as myocardial imaging agents, L represents one of the two tetradentate Schiff base ligands N,N'-ethylenebis(acetylacetone iminato), (en), or N,N'-propylene-1,2-bis(acetylacetone iminato), (pn), while Y represents a monodentate phosphine, phosphite or isonitrile ligand as exemplified by P(CH3)3, P(OCH3)3 and CN-C(CH3)3. Of these 15 complexes, several with octanol/saline partition coefficients in the range 0.04-20 exhibit significant myocardial uptake in rats and dogs. Of these, none exhibit detectable myocardial washout, providing strong support for the hypothesis that myocardial washout occurs only for those 99mTc(III) cations that undergo in vivo reduction to the neutral 99mTc(II) form. Evaluation of the prototypical complex tr-[99mTc(en)(P(CH3)3)2]+ in seven normal volunteers and patients establishes that it is only a mediocre myocardial imaging agent in man.

Animals↗
PubMed1986

Effect of reperfusion and hyperemia on the myocardial distribution of technetium-99m t-butylisonitrile.

Technetium-99m t-butylisonitrile ([99mTc]TBI) is a promising new radiotracer for myocardial imaging. Its myocardial uptake is sufficiently high in humans to permit planar, tomographic, and gated images of excellent technical quality. We studied the behavior of [99mTc]TBI in the dog at rest and under conditions of hyperemia and reperfusion in order to determine the relationship between [99mTc]TBI myocardial concentration and blood flow. After permanent occlusion of the left anterior descending artery, the correlation between the relative myocardial concentration of [99mTc]TBI and regional myocardial blood flow (RMBF) measured with radiolabeled microspheres was excellent. In a dog model of transient hyperemia, the concentration of [99mTc]TBI was directly related to blood flow but underestimated the degree of hyperemia. Technetium-99m TBI redistributed into transiently ischemic myocardium. The myocardial concentrations of [99mTc]TBI and thallium-201(201TI) in transiently ischemic myocardium were similar at 10 and 30 min following reperfusion and were significantly higher than blood flow prior to reperfusion. When [99mTc]TBI was injected into the left anterior descending artery, the washout was slow, falling to 78% of initial activity at 120 min after injection. In conclusion, [99mTc]TBI reflects regional myocardial blood flow accurately in ischemic and normal resting myocardium and underestimates blood flow at high flows. The rate of myocardial redistribution after reperfusion is similar for [99mTc]TBI and 201TI.

Animals↗
PubMed1987

Myocardial imaging with technetium-99m CPI: initial experience in the human.

The hexakis(isonitrile)technetium(I) analog [99mTc]carbomethoxyisopropyl isonitrile (CPI) has high myocardial uptake and rapid lung and liver clearance in most animal species. To evaluate [99mTc]CPI as a myocardial imaging agent in the human, we evaluated this tracer in three normals and in six patients with coronary artery disease (CAD). In normals, [99mTc]CPI cleared quickly from the lungs and accumulated in the liver and heart. The liver activity peaked at 10-15 min and cleared through the hepatobiliary system. Planar images were of excellent technical quality with high myocardial to background ratios as early as 10 min after injection. Myocardial activity fell gradually to 76.1 +/- 2.9 (s.d.)% of initial activity by 60 min after injection. In six patients with CAD, myocardial defects were present on planar images up to 2 hr after exercise and injection. In one out of six patients, the defect was not seen 3 hr after injection. In five of the six patients, normal perfusion patterns were observed 1 hr after reinjection of CPI at rest (4 hr after the initial injection). In one patient who developed spontaneous angina prior to reinjection, the perfusion defects persisted. The repeat study 3 days later with injection of [99mTc]CPI at rest was normal. Technetium-99m CPI appears to have excellent physical and biologic properties for use in association with myocardial imaging with exercise.

Coronary Disease↗
PubMed1979

Complexing of reduced technetium and tin(II) by chelating phosphate compounds. II. In vitro stability of pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes.

The in vitro stability of 99mTc- and 113Sn-pyrophosphate and ethane-1, hydroxy-1, diphosphonate (EHDP) complexes was studied by varying the mode of preparation. The 1-hr distribution in the rat was used as an indicator for complex formation or destruction. A maximum of bone uptake and urinary excretion and a minimum of soft tissue concentration was obtained if there was an excess of phosphate in relation to tin(II) in the equilibrium. Formation of tin(II) colloid was favoured in the presence of an excess of tin(II) in the equilibrium, 99mTc colloid occurred with some delay. After dilution in neutral normal saline the chelates were more or less destroyed, as shown by a 113Sn(II) colloid formation whereas the 99mTc-phosphate complexes were transformed into a 99mTc kidney agent. At pH 11 the 113Sn(II)-phosphate complexes proved to be stable, the 99mTc-phosphate complexes were also transformed into the 99mTc kidney agent. Oxidation of all tin(II) in the equilibrium by hydrogen peroxide did not change the distribution patterns of 113Sn, 99mTc was oxidized to pertechnetate. In general complexes between tin(II) and chelating phosphate compounds proved to be more stable than those with reduced technetium. EHDP was found to form stronger complexes with tin(II) and reduced technetium than pyrophosphate.

Animals↗
PubMed1985

Technetium-99m galactosyl-neoglycoalbumin: preparation and preclinical studies.

Technetium-99m galactosyl-neoglycoalbumin ([Tc] NGA), a labeled analog ligand to the hepatocyte-specific receptor, hepatic binding protein (HBP), was prepared and tested for labeling yield, stability, biodistribution, toxicity, and dosimetry. The ligand was synthesized by the covalent coupling of a carbohydrate bifunctional reagent, 2-imino-2-ethyloxymethyl-1-thiogalactose, to human serum albumin. Testing in mice and rabbits revealed the product to be nontoxic and apyrogenic. Technetium labeling yields in excess of 95%, by the electrolytic method, did not alter the molecular weight profile of the neoglycoalbumin. The NGA-bound activity remained stable for at least 4 hr. Biodistribution studies in rabbits demonstrated the liver as the single focus of tracer uptake. Dosimetry was based on kinetic studies in three baboons. Absorbed doses to liver, small intestine, urinary bladder wall, and uterus were 0.089, 0.28, 0.56, and 0.88 rad/mCi, respectively. Total body, lens of the eye, red marrow, ovaries, and testes were less than 0.06 rad/mCi. High liver specificity imparted by receptor binding combined with high labeling yield, stability, acceptable dosimetry, and safety provide [Tc]NGA with the attributes required for routine clinical assessment of hepatocyte function.

Albumins↗
PubMed1979

Complex formed from 3-hydroxy-4-formylpyridine, glutamic acid, and technetium--a possible cholescintigraphic agent.

In order to obtain a technetium-99m-labeled cholescintigraphic agent suitable for kit preparation, reactions of a variety of aromatic aldehydes, amino acids, and [99mTc] pertechnetate were examined under mild conditions. Aqueous solutions of the three reactants were heated in a boiling-water bath and the products analyzed by means of thin-layer chromatography for the formation of organic technetium complexes. 3-Hydroxy-4-formylpyridine (HFP) and 1-methyl-3-hydroxy-4-formylpyridinium chloride (N-Me-HFP) formed the complex with excellent yields, whereas 3-hydroxy-2-formylpyridine, 4-nitrosalicylaldehyde, salicylaldehyde, and isonicotinaldehyde did not. The complex is concluded to be the Tc-99m chelate of the Schiff base formed from the aldehyde and amino acbbits administered with the complex of HFP, glutamic acid and Tc-99m. The results indicate that it is promising as a cholescintigraphic agent.

Animals↗