Comparative evaluation of 99mTc GH, 99mTcO4, and 99mTc DTPA as brain imaging agents

The brain imaging properties of 99mTc glucoheptonate, 99mTc pertechnetate, and 99mTc DPTA are compared. Results demonstrate that optimum images are obtained at 90, 180, and 180 min., for 99mTc GH, 99mTc DTPA, and 99mTc perterchnetate, respectively. The former two images are not affected by prior bone imaging with 99mTc pyrophosphate, while 99mTc pertechnetate images are adversely affected. 99mTc glucoheptonate appears to be the superior agent for brain imaging, followed by 99mTc DTPA and 99mTc pertechnetate.     

Small peptides radiolabeled with 99mTc

The primary aim of this experimental investigation was to examine the effects of short-term dietary restriction on caloric consumption in eating disordered subjects. Subjects with bulimia nervosa, binge eating disorder, and overweight non-eating disordered subjects, attended a laboratory experiment during which they were randomly assigned to either a 1 h or a 6 h food deprivation condition prior to being served a multi-item buffet. The primary measure of interest was calories consumed during the laboratory experiment. Subjects deprived of food for 6 h consumed significantly more calories at the buffet compared to subjects in the 1 h food deprivation condition. However, caloric intake during the entire laboratory day was not affected by the experimental manipulation. Subjects in the longer deprivation condition apparently compensated at the buffet for the caloric restriction, but did not overcompensate.     

99mTc(V)-DMSA accumulation in gynecomastia

The accumulation of 99mTc(V)-DMSA in bilateral breasts was recognized in a 60-year-old male with drug-induced gynecomastia. There are some reports describing 99mTc(V)-DMSA accumulation in normal female breast, fibrous dysplasia of the breast and metastatic lesions of breast carcinoma, but to my knowledge, there have been no reports describing 99mTc(V)-DMSA accumulation in gynecomastia.     

Gated blood pool imaging following 99mTc stannous pyrophosphate imaging

Cardiac patients who have undergone 99mTc-stannous pyrophosphate (99mTc-PYP) myocardial imaging can be injected 24 hours later with 99mTc-pertechnetate (99mTc04) to assess left ventricular function. Reduction of 99mTc04 by tin remaining in the blood following the stannous pyrophosphate injection causes labeling of the red cells by 99mTc04 and the creation of a vascular tracer suitable for electrocardiographically gated imaging.     

The interpretation of phlebograms using fibrinogen labeled with 99 mTc

A new method for the detection of deep-vein thrombosis is presented, consisting of a single antecubital injection of fibrinogen labeled with 99mTc. This atraumatic procedure allows one to visualize the large veins of the lower limbs, the venae iliacae and the distal part of the vena cava inferior. This paper discusses how to interpret these phlebograms.     

Recombinant metallothionein-conjugated streptavidin labeled with 188Re and 99mTc

Consideration is now being given to the use of avidin (or streptavidin) and biotin for radiotherapy of tumor. Accordingly, the goal of this study was to radiolabel a mouse metallothionein-streptavidin fusion protein with 188Re and to compare its properties to those of the same fusion protein radiolabeled with 99mTc. A recombinant metallothionein-streptavidin fusion protein was radiolabeled by transchelation with 99mTc- and 188Re-glucoheptonate. Labeling efficiency, which was not optimized for either radionuclide, was approximately 60% for 99mTc and 20% for 188Re. Radiochemical purity was demonstrated by size exclusion HPLC both by nearly quantitative shifts of the 188Re label to higher molecular weight upon the addition of biotinylated antibody and by the absence of a shift with biotinsaturated 188Re-metallothionein-streptavidin. Stability of the labels in 37 degrees C serum was evaluated by comparing the HPLC radiochromatograms of serum samples both before and after the addition of biotinylated antibody. The 188Re label behaved like 99mTc in that the same peaks were evident, including one prominent peak due to labeled cysteine. Recoveries during HPLC analysis of serum samples showed that oxidation rates to perrhenate and pertechnetate were identical. However, instability to cysteine challenge was greater for 188Re; for example, the loss of label to cysteine after 24 h under one set of conditions was 41% for 188Re and 22% with 99mTc. Analysis by HPLC of liver and kidney homogenates from mice administered the labeled antibodies were qualitatively and, in large measure, quantitatively independent of label. Biodistributions at 5 h in normal mice were statistically identical between the two labels in blood and in most tissues. In conclusion, streptavidin may be radiolabeled with radiorhenium using recombinant mouse metallothionein as a bifunctional chelator, and under one set of labeling conditions at least, 188Re showed similar in vitro and in vivo behavior to that of 99mTc labeled to the same fusion protein.     

Radionuclide imaging in primary hyperparathyroidism using 99mTc sestamibi--four case reports

Radionuclide imaging using the 99mTc sestamibi either singly or as a subtraction technique with pertechnetate is a recent and reliable method in localising parathyroid adenomas prior to surgery. This is of use in pre-operative planning, as well as in failed first neck exploration. Four local patients with primary hyperparathyroidism whose parathyroid adenomas were localised by this scintigraphy are presented. The value and limitations of this imaging modality are discussed.     

Analysis of developmental data: Comparison among alternative methods.

Examined statistical issues in the analysis of repeated measures data in developmental research. The danger of bias in conventional analysis of variance has been emphasized by R. B. McCall and M. I. Appelbaum (see record 1975-00106-001), but their simulated example was markedly deviant from actual developmental data. Further, a Monte Carlo study by R. O. Collier et al (see record 1967-16063-001) has shown that the potential bias in the F tests may be accurately compensated by use of the correction factor epsilon. For illustration, a conventional analysis of variance (adjusted by epsilon) and a multivariate analysis of variance were performed on a set of actual developmental scores recorded over 6 ages. Results are comparable from both analyses, leading to the same decision about the null hypothesis at essentially the same confidence level. It is concluded that the univariate analysis qualifies as a powerful and fully protected design when used with epsilon, and the choice of procedures can be guided by the E's preference plus certain properties of the data to be analyzed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of radiochemical purity control methods for 99Tcm radiopharmaceuticals used in hospital radiopharmacies

The free fraction of pertechnetate in 99Tcm radiopharmaceuticals has to be tested for quality control reasons in line with the European Pharmacopoeia. Such quality control is often performed by miniaturized chromatographic methods. There are several recommended methods in the literature for quality control of the same radiopharmaceuticals, though it is unlikely that all methods are equivalent. Some of these methods were compared, taking into account different parameters (spot size, time required, analytical artifacts, true separation and shape of the chromatographic peaks, ease of handling), to verify the best method for the control of each radiopharmaceutical. It would appear that instant thin layer chromatography silica gel is the best support for these miniaturized methods, using MEK as solvent to check DTPA, DMSA, gluconate, pyrophosphate, medronate and phytate; NaCl 20% solution is the best solvent for IDA derivatives, human albumin and albumin particles (microspheres, macroaggregates).     

Comparison of single sample methods for determination of plasma clearance using 99mTc-MAG3

We compared relationship among three single blood sampling methods which have been proposed for determination of plasma clearance with 99mTc-MAG3. Russell's and Bubeck's algorithms were employed for 48 adults (average age: 53 years) and Bubeck's and Piepsz's algorithms were used in 9 children (average age: 5.8 years). Three methods showed very high correlation among them. However, Russell's and Piepsz's methods were about 1.4 times higher than Bubeck's method in calculating plasma clearance of 99mTc-MAG3. The present study indicates that three methods discussed here are useful for the determination of plasma clearance with 99mTc-MAG3. In addition, Bubeck's method may be preferable as a reference for single plasma sampling method because of common application to adults and children.     

Gastric emptying of 99mTc tagged solid food in gastric and duodenal ulceration

This study is to analyze gastric emptying (GE) of 99mTc tagged solid meals in 43 gastric ulcer (GU), 16 duodenal ulcer (DU) patients, and 15 normal subjects. Diagnosis of active ulcers had been made through high gastrointestinal endoscopy. The patients with GU were divided into three groups according to Johnson's classification. Gastric contents were measured at 15 minute intervals over a period of 150 minutes, with the person standing in front of a gamma-counter. The GE curve was obtained from the mean percentile of radioactivity of all the groups measured at 15 minute intervals. Results were submitted to statistical analysis. Significant delay in GE in DU patients compared to normals, type II and Type III group. However, GE of type I GU was not statistically different from the DU group nor of types II and III GU, occupying an intermediate e position.     

Radioimmunoimaging assay of ovarian tumor with 99mTc labeled anti-carcinoembryonic antigen monoclonal antibody

Radioimmunoimaging (RI I) assay with 99mTc labeled anti-CEA monoclonal antibody was performed in 31 patients with suspected primary or recurrent malignant ovarian tumor. The radiation dose raging from 920MBq to 110MBq(1mgIgG) was administered i.v. for each patient. Anterior-posterior views of the pelvis and abdomen were obtained routinely with gamma-camera during 18-24 hour after the application of antibody. The results of RII were compared with the findings in operation or CT examination. Sensitivity in diagnosis was 100% (13/13), specificity was 94%(16/17) and metastatic foci sensitivity was 63%(10/16). The serum CA125 in this study appeared to be correlated with the results of RII. However, in 2 patients with normal serum CA125 titers RII revealed true positive. The preliminary clinical results of RII with 99mTc-MAb showed that RII is a promising method for the detection of malignant ovarian tumors.     

An in-vitro study of 99mTc sestamibi uptake by normal and neoplastic cell lines

The hexakis (2-methoxy isobutyl isonitrile) technetium (I) (99mTc MIBI) is a representative molecule for a class of monocationic lipophile 99mTc compounds, knowing to be initially used like myocardial scintigraphic agents, and now also in oncological scintigraphy. This present study aims to compare the in vitro 99mTc MIBI cellular uptake on some normal and neoplastic cells. Three tumoral cell lines were used: M4Beu (pigmented melanoma), M3Dau (pigmented melanoma), MCF7 (breast cancer), in comparison with newborn rat cardiac myocytes and fibroblasts. Monolayers cultures cell were incubated for 1 hour with 37 kBq of 99mTc MIBI. Our results: (a) confirm a preferentially 99mTc MIBI uptake on the myocytes in comparison of the fibroblasts; (b) show that this uptake is very different on the neoplastic studied cultures cells, depending on the cell type (higher on M3Dau in comparison of the other two malignant cell lines, and also higher than the myocytes. The neoplastic cellular mechanisms to accumulate 99mTc MIBI, are only hypothetically understand; there are thought to be also in relation with the Nernst equations, applied at the plasmatic and mitochondrial membranes level, like in normal cells. A correlation with some phenotypic neoplastic cells characteristics, in relation with the malignancy tumoral potential seems possible. If there is the case, this can be a possible explanation of some in vivo imaging results, obtained with 99mTc MIBI, in oncologic scintigraphy.     

99mTc human immunoglobulin scintigraphy--a reliable method to detect joint activity in rheumatoid arthritis

The ability of 99mtechnetium labelled nonspecific, polyclonal human immunoglobulin G (99mTc-IgG) scintigraphy to depict and quantify synovial inflammation was studied in 30 patients with rheumatoid arthritis (RA). All patients were injected with 350 MBq 99mTc-IgG and imaging was performed 4 h later. This resulted in excellent images of inflamed synovium. Scores for 99mTc-IgG joint scintigraphy correlated highly with scores for joint swelling and C-reactive protein levels, weakly with pain scores and not with radiographic scores of joint destruction. These results suggest that 99mTc-IgG joint scintigraphy may provide an objective test to detect synovitis and measure the activity of the disease.     

An approach to cardiac malposition and the heterotaxy syndrome using 99mTc sulfur colloid imaging

A diagnostic approach to cardiac malposition and the heterotaxy syndrome is outlined. The 99mTc sulfur colloid intravenous forward angiocardiogram and plain chest radiograph are used to determine the two key diagnostic points: position of the venous atrium and stomach. If located on the opposite sides of the body, four basic situs configurations are possible, and the presence of associated cardiac anomalies may be predicted. For the two configurations in which the cardiac apex is on the same side as the stomach, the incidence of associated cardiac anomalies is low; when on opposite sides, the indicence is high. If the venous atrium and stomach are on the same side, then abdominal heterotaxy with associated splenic abnormality is present. Dynamic 99mTc sulfur colloid imaging will usually show interruption of the inferior vena cava, if present, and multiple or absent spleens.     

Comparison of several model-based methods for analysing incomplete quality of life data in cancer clinical trials

This paper considers five methods of analysis of longitudinal assessment of health related quality of life (QOL) in two clinical trials of cancer therapy. The primary difference in the two trials is the proportion of participants who experience disease progression or death during the period of QOL assessments. The sensitivity of estimation of parameters and hypothesis tests to the potential bias as a consequence of the assumptions of missing completely at random (MCAR), missing at random (MAR) and non-ignorable mechanisms are examined. The methods include complete case analysis (MCAR), mixed-effects models (MAR), a joint mixed-effects and survival model and a pattern-mixture model. Complete case analysis overestimated QOL in both trials. In the adjuvant breast cancer trial, with 15 per cent disease progression, estimates were consistent across the remaining four methods. In the advanced non-small-cell lung cancer trial, with 35 per cent mortality, estimates were sensitive to the missing data assumptions and methods of analysis.     

99mTc pertechnetate scintigraphy and premedication for the search for ectopic gastric mucosa in Meckel's diverticulum

BACKGROUND: Meckel's diverticulum (MD) is the most common anomaly of the large intestinal tract (1-3%) and is more frequent in children (62% < 2 years) and in males (66%). It often involves ectopic gastric mucosa which manifests through gastrointestinal bleeding in 50% of cases. 99m-Technetium scintigraphy (99mTcO4) is one of the procedures available for the non-invasive diagnosis of ectopic gastric mucosa. METHODS: Twenty-eight patients (11 females, 17 males), including 16 children and 12 adults, aged 8 months-80 years old, were included in the study. The patients were admitted to hospital for hematochezia and melena (22) associated with abdominal pain (5): 3 patients repeatedly presented occult blood in their stools. Two patients only suffered from abdominal cramps and one only anemia. Patients were studied using plain abdominal radiographs and ultrasound; 10 underwent gastroscopy and colonoscopy; radiological contrast studies were performed in 5 patients. All tests were inconclusive. All the patients were premedicated with oral cimetidine (20 mg/kg in pediatric patients and 300 mg q.i.d. for adults, 48 hours before the test) or with ranitidine i.v. (1 mg/kg, max 50 mg, in 20 minutes, one hour before the test); barium meals and colonoscopy were deferred for 2-3 days after examination. An intravenous injection of 37-180 Mbq of 99mTcO4 was given followed by a dynamic study of the abdomen in anterior projection. Images were acquired for one hour or until the visualisation of abnormal foci of intake: in this case, lateral and oblique images were acquired for a better localisation of the suspicious area. Some patients were administered furosemide i.v. (0.75 mg/kg). All underwent a follow-up period of 12 months. RESULTS: Pertechnetate scintigraphy was positive in 10 cases and the presence of ectopic gastric mucosa was confirmed by surgery. The study was negative in 18 cases: 3 of them were discharged with a diagnosis of Salmonella infection, polyp of the small bowel or ulcer of the large bowel respectively; the other 15 patients did not show symptoms of onset during follow-up. CONCLUSIONS: These results confirm the high diagnostic accuracy of pertechnetate scintigraphy to detect ectopic gastric mucosa if associated with H2-receptor-blocking agent premedication.     

The accuracy of ultrasonography and 201Tl-99mTc subtraction scan in localization of parathyroid lesions

Pulsed xenon chloride excimer and holmium laser-tissue interaction is primarily based on tissue water vaporization. Consequently, each ablative laser pulse produces a rapidly expanding and imploding vapour bubble in blood or the target tissue. In experimental studies, explosive water vaporization is the major mechanical cause of observed tissue dissections. By reduction of the induced bubble volume, a reduction in experimentally and clinically observed dissections after coronary excimer laser angioplasty is to be expected. This reduction of mechanical damage, however, in combination with efficient and substantial plaque debulking is the major challenge in the development of laser angioplasty.