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.     

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.     

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.     

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.     

Comparison among several 99mTc antibody-labeling methods

The effects of angiotensin-converting enzyme (ACE) inhibition with perindopril on renal vascular structure were studied in control and streptozotocin diabetic male Sprague-Dawley rats after 3 weeks. After kidneys were perfusion-fixed at systolic blood pressure, morphometric analysis of vascular structural changes in the media of the renal vasculature at the cortico-medullary junction was performed. Vascular hypertrophy was present in the diabetic vessels, as assessed by an increase in medial cross-sectional area for a given lumen size. This relative increase in medial area was prevented by perindopril treatment, consistent with an antitrophic effect on diabetic kidney vessels by ACE inhibition. The diabetic kidney had an increased proportion of small vessels less than 50 microns diameter at the cortico-medullary junction, perhaps representing diabetes induced angiogenesis. This subpopulation of vessels was reduced in number after perindopril treatment. Our data support a role for increased activity of angiotensin converting enzyme as a mechanism for vascular hypertrophy, which may be involved in the pathogenesis of diabetic vasculopathy and nephropathy.     

Pharmacokinetics of 99Tcm-pertechnetate and 188Re-perrhenate after oral administration of perchlorate: option for subsequent care after the use of liquid 188Re in a balloon catheter

The relationship between the biosynthesis of long-chain fatty acids and their distribution in the key organs of hypertension is of considerable interest because of their role in the production of vasoactive eicosanoids and their effects on membrane properties. The present study analyzed the fatty acid compositions of the total lipids in the kidney, aorta, heart, and hepatocytes of 1-, 3-, and 6-mon-old spontaneously hypertensive rats (SHR) and their normotensive controls, Wistar Kyoto rats (WKY) by capillary gas chromatography . The major changes concerned the polyunsaturated fatty acids (PUFA). The percentage of arachidonic acid (AA) was significantly greater in the 1-mon-old SHR kidney than in the WKY kidney, but it was lower at 3 and 6 mon. The percentage of eicosapentaenoic acid was very low in the SHR kidney. The results for the aorta were similar, with marked decreases in 18:2n-6 and 18:3n-3 in SHR aged 1 and 6 mon. Despite a higher proportion of 18:2n-6 and AA at 6 mon, there was no major change in the SHR heart lipids. The fatty acid spectrum in the liver provides additional evidence for the previously reported inhibition of desaturase activities in SHR. Thus, this study shows that the PUFA composition is modified differently in different tissues in SHR, and this may be related to the pathogenesis of hypertension in these animals.     

Organ distribution of canine leukocytes labeled with 99mTc-sulfur colloid

Previous reports have shown that scintigraphic localization of acute inflammation can be achieved using autologous leukocytes labeled in vitro with 99mTc-sulfur colloid (TcSC). The technique is limited, however, by a marked accumulation of radioactivity in the lungs and liver of normal animals. A modified procedure was developed using preparations of TcSC of small particle size to label blood leukocytes in vitro. Markedly decreased levels of lung and liver radioactivity and elevated levels of blood radioactivity were found after intravenous infusion of autologous canine leukocytes labeled by this method. These leukocytes could be used to image areas of acute inflammation resulting from induction of septic or sterile venous thrombi.     

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.     

99mTc-HMPAO labeled leukocyte SPECT in intracranial lesions

BACKGROUND: Scintigraphy with 111In (indium-111)-oxine or 99mTechnetium-hexamethylpropyleneamine oxime (99mTc-HMPAO) labeled leukocytes has been used to differentiate brain abscess from brain tumor. However, there are false positive or false negative results from planar scintigraphic images. So a more specific and sensitive scintigraphic technique needs to be developed. METHODS: Planar and single photon emission computed tomography (SPECT) images were obtained and reviewed in 14 patients with intracerebral ring-enhancing lesions on computed tomography (CT) or magnetic resonance imaging (MRI). In all patients, diagnosis was confirmed by histopathologic examination. The effect of steroids or antibiotics on scintigraphic finding was examined. RESULTS: Abscess was confirmed in six patients, tumor in six, tuberculoma and cysticercosis in one each, respectively. In all the patients with abscess, SPECT showed increased focal activity irrespective of steroid or antibiotic therapy. Increased radioactivity, which could not be detected on planar images, could be identified in two patients with abscess. In three of the six patients with tumor, radiolabeled leukocytes did not accumulate in the tumor. In the other three patients with tumor, SPECT showed focally increased activity that was less intense than the activity shown in the patients with abscess. CONCLUSIONS: 99mTc-HMPAO labeled leukocyte SPECT is useful for the differential diagnosis of intracerebral ring-enhancing lesions, and the use of steroids or antibiotics does not influence the sensitivity of SPECT. Diagnostic sensitivity of scintigraphy with labeled leukocytes could be improved by SPECT in addition to planar image.     

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.     

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.     

Contamination from 131I, 103Ru, and 239Np in the eluate of 99Mo-99mTc generators loaded with (n, gamma)-produced 99Mo

Iodine-131, ruthenium-103, and neptunium-239 are present as contaminants in the eluate of 99Mo-99mTc generators loaded with 99Mo prepared by thermal-neutron irradiation of enriched 98Mo. The elution pattern of each of these contaminants is determined, together with the amounts found in the eluate of all generators tested over a 7-month period.     

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.     

Pitfall in 201Tl-99mTc subtraction scintigraphy: a case of 99mTc-pertechnetate uptake in a parathyroid hyperplasia]

201Tl-99mTc subtraction scintigraphy has been recognized as a useful procedure in the preoperative localization of hyperfunctioning parathyroid glands. We experienced a case which showed 99mTc-pertechnetate uptake in a parathyroid hyperplasia. This case warned us to focus a lot of attention on the detection for preoperative localization. There has been no such case reported in the previous Japanese literatures. Hypervascularity and thick fibrous capsule presumed explanation for a rare case of marked pertechnetate uptake into a parathyroid hyperplasia.     

188Re- and 99mTc-MAG3 as prosthetic groups for labeling amines and peptides: approaches with pre- and postconjugate labeling

Either radiolabeled Tc-99m- or Re-188-labeled MAG3-4-nitrophenylester or unlabeled Bz-MAG3-4-nitrophenylester was reacted with amines and peptides to follow a pre- or a postconjugate radiolabeling route, respectively. The model compounds were N'-t-butyloxycarbonyl-1,6-diaminohexane (DH-Boc) and a Lys-protected derivative of the somatostatin analog RC-160 (cyclic D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2). In the case of labeling DH-Boc, both the preconjugate labeling and the postconjugate labeling were found by using analytical HPLC to provide identical radiolabeled compounds regardless whether Re-188 or Tc-99m was used. The results are supported by infrared and mass-spectral data obtained from compounds synthesized using stable rhenium. The 188Re- or 99mTc-MAG3-RC-160 somatostatin analog were synthesized following the preconjugate labeling route and subsequent removal of the protecting group. Biodistributions of 188Re-and 99mTc-MAG3-RC-160 were evaluated in normal and tumor-bearing mice, and were similar to those of radioiodinated 131-RC-160. All radiolabeled analogs of RC-160 were rapidly cleared from the blood and were excreted through the hepatobiliary system with very little normal organ uptake. The tumor uptake (PC-3, human prostate adenocarcinoma) of systemically administered Re-188-MAG3-RC160 was very low, and it reached only 0.28% injected dose/g (%IDg) at 24 h postinjection, similar to what was obtained with I-131-RC-160. Intratumor injections resulted in significant tumor retentions (9.3% ID/g at 24 h).     

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.     

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.