Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Technetium Compounds”

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 487 records · Page 27Linked to original sources
PubMed1997

[Scintillation probe guided sentinel lymphadenectomy in malignant melanoma].

In cutaneous melanoma, biopsy of the first tumor-draining lymph node (Sentinel node, SLN) may replace routine elective lymph node dissection (ELND). The SLN has been shown to contain the first micrometastasis in early lymphatic tumor dissemination. As micrometastases were identified in 10-30% of stage I (AJCC/UICC) patients, sentinel lymphonodectomy (SLND) should enable us to select patients clinically in stages I and II, but histopathologically in stage III. This optimization of patient selection is mandatory as only this subgroup profits from ELND. Since the beginning of 1995 we was scintillation detector (gamma probe)-guided sentinel biopsy in patients with a melanoma > 1.0 mm and clinically negative lymph nodes. After injecting colloidal 99m-Tc-labelled tin(II)-sulfide solution around the tumor (or the biopsy scar), the SLN can be localized exactly. The technique is minimally invasive and easy to handle. If the SLN contains tumor, a standard en bloc lymphonodectomy is performed. Long-term follow-up, however, is needed to delineate the role of this procedure in melanoma treatment.

Adult↗
PubMed1996

["Sentinel" lymphonodectomy with scintillation detector. A new strategy in treatment of malignant melanoma].

For decades the results of elective lymph node dissection (ELND) are differently discussed, so that it is not definitely recommended at present the less so since the morbidity of this operation can't be neglected. Since the beginning of 1995 we practice a gamma-probe guided sentinel lymphonodectomy (SLNE) on patients with melanoma from a Breslow tumor thickness of 1 mm upward, after injecting a colloidal 99m-Tc labelled tin (II) - sulfide solution around the tumor or the scar, if the tumor has been excided before. By this method, that allows a selection of patients who according clinically to a stage I or II (UICC) but even histopathologically to a stage III and who are profiting of a removal of the regional lymph nodes, the sentinel node can be exactly localised, tissue-sparing removed at minimal complication rates and the completeness of the removal can be verified by measurements of the radioactivity. When finding metastases in the histopathological examination of the node a dissection of the whole region follows.

Adult↗
PubMed2002

Comparative microvascular exchange kinetics of [(77)Br]bromide and (99m)Tc-DTPA in humans.

The plasma clearance curves of small hydrophilic solutes comprise three exponentials, consistent with a three-compartmental distribution model. A previous comparison between inulin and diethylene triamine penta-acetic acid (DTPA) suggested that these three compartments are in series, the first being plasma and the second and third representing compartments within the extravascular space. Moreover, whilst the total distribution volumes of these two indicators were similar, the volume of the second compartment was higher for DTPA. The purpose of the current study was to investigate whether a solute smaller than DTPA, namely bromide, fits the hypothesis that the second space volume is an inverse function of the size of the solute. Two groups of subjects were studied: group A comprised eight patients undergoing routine diagnostic arteriography and group B, eight patients referred for routine measurement of glomerular filtration rate plus two normal volunteers. (99m)Tc-DTPA and sodium [(77)Br]bromide were intravenously administered simultaneously. In group A, frequent arterial samples were obtained up to 40 min after injection, and antecubital venous samples 30 s after each arterial sample. In group B, frequent venous samples were obtained up to 280 min after injection. Volume measurements based on bromide were corrected for erythrocyte bromide accumulation. In both subject groups, the normalised venous concentration ratio of bromide to DTPA, corrected for red cell bromide uptake, was significantly less than unity in the earliest blood samples, being 0.56 (SD 0.08) at 1 min, consistent with faster diffusion of bromide from plasma to interstitial fluid. Furthermore, the extraction fraction of bromide from plasma to interstitial fluid in the forearm was about 0.6, higher than that of DTPA (about 0.5) in spite of red cell bromide accumulation which equilibrated with plasma bromide within 20 s and resulted in a red cell to plasma concentration ratio of 0.51 (0.09). Nevertheless, the net extraction fractions of the two solutes approached asymptotic values with identical time courses over 20-25 min. The total volume of distribution of bromide in group B was 22.5 (3.8) litres, which was higher than that of DTPA, 18.0 (2.8) litres ( P<0.001). It was assumed that this difference was the result of intracellular bromide accumulation. After correction for this, the combined volume of the first and second spaces was significantly higher for bromide, at 13.9 (2.9) litres, than for DTPA, 12.3 (2.0) litres ( P<0.05), but the volume of the third space, 4.1 (2.8) litres, was less compared with DTPA, for which it was 5.8 (2.2) litres ( P<0.05). The proportion of the total space occupied by the first and second spaces was also higher for bromide, 0.78 (0.14), than for DTPA, for which it was 0.69 (0.09; P<0.05). These data are consistent with a three-in series-compartmental model of solute distribution in which the volume of the second space is an inverse function of solute molecular size while the volume of the third is a positive function of solute size.

Bromides↗
PubMed2004

Diagnosis and staging of children's lymphoma using the technetium-labelled somatostatin analogue, 99mTc-depreotide.

Somatostatin receptor scintigraphy (SRS) is useful in diagnosing tumours with increased expression of somatostatin receptors. Lymphoma cells are known to express somatostatin receptors; however, the application of indium-labelled analogues in children is limited. The aim of this study was to investigate whether the technetium-labelled somatostatin analogue, depreotide, may be useful in diagnosing and staging malignant lymphoma in children. Fifteen children (mean age 13.8 years) with malignant lymphoma were studied (eight with Hodgkin's lymphoma and seven with non-Hodgkin's lymphoma). All children were investigated for verification of staging established by other modalities. Imaging was performed 3-5 h after administration of 300-550 MBq (99m)Tc-depreotide. All patients underwent whole-body scan and single-photon emission tomography of the chest and/or abdomen. Images were assessed visually. In all patients, foci of increased tracer uptake were found. The neck and thorax were the most frequent lesion localisations. Abdominal lesions were found in four patients, and bone lesions in three. In two patients, diffusely increased uptake was observed throughout the skeleton (verified as representing bone marrow involvement). In 11 patients, the number of abnormal sites detected by SRS was greater than that detected by CT. Based on radionuclide examination, three children were upstaged and none were downstaged. It is concluded that (99m)Tc-depreotide shows increased accumulation in pathological sites in malignant lymphoma in children. SRS with (99m)Tc-depreotide provides a single-day imaging method with high sensitivity in lymphoma and with all the advantages of a technetium-labelled compound. Further studies are required on the specificity and the possible value of (99m)Tc-depreotide in the follow-up of these patients.

Adolescent↗
PubMed2004

CT-guided lymphoscintigraphy in patients with squamous cell carcinoma of the head and neck: a feasibility study.

Accurate knowledge of lymphatic drainage facilitates planning of surgery for patients with squamous cell carcinoma of the head and neck. The aim of this study was to evaluate the feasibility of a new injection technique for lymph node detection in patients with squamous cell carcinoma of the hypopharynx and larynx, in whom simple peritumoural injection is hampered by the tumour localisation. Computed tomography (CT)-guided lymphoscintigraphy was performed in a total of 13 patients with squamous cell carcinoma of the hypopharynx and larynx who could not be injected by simple visual inspection. In a first step, contrast medium-enhanced axial 5-mm-thick CT slices of the neck were obtained. After tumour localisation on these CT images, 1-2 ml contrast medium and, in the event of appropriate distribution, subsequently 50 MBq technetium-99m colloid were injected at one to three peritumoural sites under CT guidance. Peritumoural tracer distribution was controlled by thin-slice CT. Subsequently, planar scintigrams from anterior, right and left lateral views were obtained. In all patients, peritumoural colloid application was feasible, as shown on control CT scans. Post injection, neither severe nor minor complications were noted. The patients complained of only low pain sensations with an average score of 1.8 on a pain scale from 0 to 10. Lymphatic drainage was identified in nine of the 13 patients, with a total of 14 detected lymph nodes. In six patients, ipsilateral sentinel lymph nodes were visualised; bilateral sentinel lymph nodes were identified in one patient and contralateral lymphatic drainage was observed in two patients. CT-guided lymphoscintigraphy is a feasible and minimally invasive diagnostic tool for sentinel lymph node detection in patients with squamous cell carcinoma of the hypopharynx and the larynx. In contrast to endoscopic colloid injection under general anaesthesia, this technique seems to be a well-tolerated method for lymphatic mapping prior to surgical procedures.

Adult↗
PubMed2000

Simplified quantification of dopamine transporters in humans using [99mTc]TRODAT-1 and single-photon emission tomography.

Quantification of dopamine transporters (DAT) using [99mTc]TRODAT-1 and single-photon emission tomography (SPET) requires full kinetic modeling of the data, using complex and invasive arterial blood sampling to provide an input function to the model. We have shown previously that a simpler reference tissue model provides accurate quantitative results, using a reference region devoid of DAT as the input to the model and thereby obviating the need for blood sampling. We now extend this work into humans, and develop further simplifications to make the imaging protocol much more practical as a routine procedure. Fourteen healthy subjects (age 29.8 +/- 8.4 years, range 18.7-45.5 years) underwent dynamic SPET for 6 h following injection of 752 +/- 28 MBq [99mTc]TRODAT-1. The kinetic data were analyzed using nonlinear regression analysis (NLRA) and Logan-Patlak graphical analysis. In addition, simple average ratios of striatal-to-background counts were obtained for three 1-h periods (3-4 h, 4-5 h, 5-6 h), and compared against the kinetic models. All methods gave an index of specific binding, proportional to the binding potential, known as the distribution volume ratio (DVR). The reference tissue NLRA gave mean values of k3=0.013 +/- 0.003 min(-1), k4=0.011 +/- 0.002 min(-1), and DVR=2.29 +/- 0.17. Graphical analysis gave a value of DVR=2.28 +/- 0. 16, and the three ratio values of DVR were: 3-4 h, 2.18 +/- 0.15; 4-5 h, 2.34 +/- 0.13; and 5-6 h, 2.46 +/- 0.19. Graphical analysis was highly correlated with NLRA (R2=0.91, slope=0.90 +/- 0.08). The ratio methods correlated well with NLRA (3-4 h, R2=0.71, slope= 0.73 +/- 0.13; 4-5 h, R2=0.86, slope=0.73 +/- 0.09; 5-6 h, R2=0.80, slope=1.00 +/- 0.15), and also with graphical analysis (3-4 h, R2=0.65, slope=0.74 +/- 0.16; 4-5 h, R2=0.85, slope=0.78 +/- 0.09; 5-6 h, R2=0.88, slope=1.11 +/- 0.12). The optimum equilibrium time point for obtaining a simple ratio was approximately 4.5-5.5 h. In conclusion, the simple ratio techniques for obtaining a quantitative measure of specific binding correlated well with the reference tissue kinetic models, using both NLRA and graphical analysis. The optimum time for obtaining a ratio appeared to be in the range 4.5-5.5 h. Earlier time points, while still relatively accurate, had a lower sensitivity and may not be optimized for measuring small changes in DAT concentrations.

Adolescent↗
PubMed1998

Application of transmission scan-based attenuation compensation to scatter-corrected thallium-201 myocardial single-photon emission tomographic images.

A practical method for scatter and attenuation compensation was employed in thallium-201 myocardial single-photon emission tomography (SPET or ECT) with the triple-energy-window (TEW) technique and an iterative attenuation correction method by using a measured attenuation map. The map was reconstructed from technetium-99m transmission CT (TCT) data. A dual-headed SPET gamma camera system equipped with parallel-hole collimators was used for ECT/TCT data acquisition and a new type of external source named "sheet line source" was designed for TCT data acquisition. This sheet line source was composed of a narrow long fluoroplastic tube embedded in a rectangular acrylic board. After injection of 99mTc solution into the tube by an automatic injector, the board was attached in front of the collimator surface of one of the two detectors. After acquiring emission and transmission data separately or simultaneously, we eliminated scattered photons in the transmission and emission data with the TEW method, and reconstructed both images. Then, the effect of attenuation in the scatter-corrected ECT images was compensated with Chang's iterative method by using measured attenuation maps. Our method was validated by several phantom studies and clinical cardiac studies. The method offered improved homogeneity in distribution of myocardial activity and accurate measurements of myocardial tracer uptake. We conclude that the above correction method is feasible because a new type of 99mTc external source may not produce truncation in TCT images and is cost-effective and easy to prepare in clinical situations.

Adult↗
PubMed1998

Stability versus reactivity of "3+1" mixed-ligand technetium-99m complexes in vitro and in vivo.

"3+1" technetium-99m mixed-ligand complexes as relevant to the development of a third generation of 99mTc radiopharmaceuticals were investigated in vivo and in vitro in the blood of rats. Surprisingly, in whole blood the complexes, which proved to be stable in saline, PBS of pH 7.4 and in plasma, were converted into two radioactive, more hydrophilic metabolites. Small structural differences in the complex molecule have a profound influence on the rate of metabolism of the complexes. To obtain an understanding of this unexpected reactivity, transchelation reactions with glutathione (GSH) were hypothesized and this hypothesis substantiated by challenge experiments carried out with a series of 99mTc and analogous rhenium complexes and GSH. In vitro studies in human plasma, whole blood and erythrocytes also revealed conversion of the complexes, though, at a much slower rate. Structural parameters influencing the stability of the complexes and consequences for the radiopharmaceutical design are discussed.

Animals↗
PubMed1998

Simultaneous acquisition of iodine-123 emission and technetium-99m transmission data for quantitative brain single-photon emission tomographic imaging.

The aim of this study was to obtain quantitative iodine-123 brain single-photon emission tomographic (SPET) images with scatter and attenuation correction. We used a triple-headed SPET gamma camera system equipped with fan-beam collimators with a technetium-99m line transmission source placed at one of the focal lines of the fan-beam collimators. Four energy windows were employed for data acquisition: (a) 126-132 keV, (b) 132-143 keV, (c) 143-175 keV and (d) 175-186 keV. A simultaneous transmission-emission computed tomography scan (TCT-ECT) was carried out for a brain phantom containing 123I solution. The triple energy window scatter correction was applied to the 123I ECT data measured by means of the windows (b), (c) and (d) acquired by two detectors. Attenuation maps were reconstructed from 99mTc TCT data measured by means of the windows (a), (b) and (c) acquired by one detector. Chang's iterative attenuation correction method using the attenuation maps was applied to the 123I ECT images. In the phantom study cross-calibrated SPET values obtained with the simultaneous mode were almost equal to those obtained with the sequential mode, and they were close to the true value, within an error range of 5.5%. In the human study corrected images showed a higher grey-to-white matter count ratio and relatively higher uptake in the cerebellum, basal ganglia and thalamus than uncorrected images. We conclude that this correction method provides improved quantification and quality of SPET images and that the method is clinically practical because it requires only a single scan with a 99mTc external source.

Algorithms↗
PubMed1998

The impact of tumour volume and other characteristics on uptake of radiolabelled monoclonal antibodies in tumour tissue of head and neck cancer patients.

Radioimmunotherapy (RIT) seems to be a realistic option for eradication of minimal residual squamous cell carcinoma of the head and neck (HNSCC), although uptake levels of radiolabelled monoclonal antibodies (MAbs) in tumour tissue vary strongly. The aim of this study was to obtain greater insight into the factors influencing the accumulation of MAbs in HNSCC. Twenty-seven HNSCC patients were injected with radiolabelled MAb E48 or U36 and underwent surgery 2 days after injection. Radioactivity was measured in tumour biopsies taken from the surgical specimen. Uptake levels were correlated with various patient, tumour and MAb characteristics, including age, sex, site, TNM stage, volume as assesssed by computed tomography or magnetic resonance imaging, degree of differentiation, antigen expression of the tumour, the particular MAb that had been injected and the MAb dose. A stepwise regression multivariate analysis showed that tumour volume is the most significant prognostic factor (P=0. 01) for MAb uptake. In conclusion, a significantly higher MAb uptake is found in small tumours as compared to larger tumours. Therefore, RIT may be particularly effective in head and neck cancer patients when used in an adjuvant setting.

Aged↗
PubMed1999

A deconvolution technique for processing small intestinal transit data.

The deconvolution technique can be used to compute small intestinal impulse response curves from scintigraphic data. Previously suggested approaches, however, are sensitive to noise from the data. We investigated whether deconvolution based on a new simple iterative convolving technique can be recommended. Eight healthy volunteers ingested a meal that contained indium-111 diethylene triamine penta-acetic acid labelled water and technetium-99m stannous colloid labelled omelette. Imaging was performed at 30-min intervals until all radioactivity was located in the colon. A Fermi function=(1+e-alphabeta)/(1+e(t-alpha)beta) was chosen to characterize the small intestinal impulse response function. By changing only two parameters, alpha and beta, it is possible to obtain configurations from nearly a square function to nearly a monoexponential function. Small intestinal input function was obtained from the gastric emptying curve and convolved with the Fermi function. The sum of least squares was used to find alpha and beta yielding the best fit of the convolved curve to the observed small intestinal time-activity curve. Finally, a small intestinal mean transit time was calculated from the Fermi function referred to. In all cases, we found an excellent fit of the convolved curve to the observed small intestinal time-activity curve, that is the Fermi function reflected the small intestinal impulse response curve. Small intestinal mean transit time of liquid marker (median 2.02 h) was significantly shorter than that of solid marker (median 2.99 h; P<0.02). The iterative convolving technique seems to be an attractive alternative to ordinary approaches for the processing of small intestinal transit data.

Adult↗
PubMed2003

Intraoperative location of small gastrointestinal cancers with a handheld gamma probe.

The location of a small lesion must be precisely identified during laparoscopic surgery. A gamma probe that is usually used for navigating sentinel lymph nodes was evaluated for its usefulness in locating small gastrointestinal lesions (14 gastric and 10 colonic). A total of 2 mCi of a Tc(99m)-labeled rhenium colloid was injected endoscopically around a tumor 16 h prior to surgery. During operation, the abdominal cavity was scanned using a handheld gamma probe (Navigator GPS, Tyco HealthCare, Norwalk, CT, USA). In all cases, the injection site was identified as the highest spot in the abdominal cavity, with 2585 counts per second on average (range, 910-8800 counts per second). The highest count in a lymph node was 637 per second on average. The gamma probe is a useful tool for identifying small gastrointestinal lesions during open and laparoscopic operations.

Colectomy↗
PubMed2002

Small colonic J-pouch improves colonic retention of liquids--randomized, controlled trial with scintigraphy.

PURPOSE: A small 6-cm colonic J-pouch improves stool frequency and continence, without stool evacuation problems. However, the reservoir function is not improved on physiologic studies. Hence, a scintigraphy technique was devised to study the transit of solid and liquid colonic contents in these patients. METHODS: Patients were randomly assigned to straight or colonic J-pouch anal anastomoses after ultralow anterior resection. At 1 year after surgery, they were studied by bowel questionnaire, anorectal manometry, and technetium TC 99m tin-colloid liquid test meal/I-131 microcapsule scintigraphy. In the latter, technetium TC 99m tin-colloid was ingested orally to image the colonic liquids. I-131 microcapsules taken simultaneously imaged the solid stools. After ingestion of the radioisotopes, imaging was performed at intervals of 7 to 8, 24, and 56 hours later. Two independent observers noted the presence of technetium TC 99m tin-colloid liquid and I-131 microcapsules in various areas of interest drawn over the colon. RESULTS: There were six patients (5 males, mean age, 61.5 (SE mean, 1.9) years) in the straight, and six patients (5 males, mean age, 63.2 (4.5) years) in the colonic J-pouch group. Stool frequency was more in the straight group (4.8 (0.4) vs. 3 (0.2) stools/day; P <.001). Continence, evacuation problems, and anorectal physiologic findings were not different. Technetium TC 99m tin-colloid (imaging liquids) transited significantly faster than I-131 microcapsules (imaging solids), at various areas of interest in the colon. In the colonic J-pouch patients, technetium TC 99m tin-colloid liquid was retained significantly longer in the descending colon at 24 hours (P <.05). Stool frequency was higher when technetium TC 99m tin-colloid was not retained in the descending colon at 56 hours (3.3 (0.5) vs. 4.3 (0.4) stools/day) but this did not reach statistical significance. There were no significant differences in the distribution of the ingested I-131 microcapsules between colonic J-pouch and straight groups. CONCLUSIONS: Reduced stool frequency after colonic J-pouch may be related to factors causing better retention of liquid stools in the distal colon. No difference in solid stool transit could possibly account for minimal evacuation problems in small pouches.

Aged↗