PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Technetium Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 829 records · Page 46Linked to original sources
PubMed1989

A comparison of liver-spleen ratios and uptakes obtained using planar and tomographic techniques.

Liver-spleen ratio, volume and uptake were measured in 20 patients undergoing routine 99Tcm-colloid examinations. Methods using planar views only were compared with results obtained using SPECT techniques and automated slice processing. The results suggest that a reasonable estimate of liver-spleen ratio may be obtained using anterior and posterior planar views only. Estimates of organ volume and absolute uptake were not reliably obtained using planar views only, and SPECT studies are required. The choice of attenuation correction technique for SPECT studies did not affect the results obtained for liver-spleen ratios and volumes, although systematic underestimation of absolute uptake occurred with simpler techniques.

Adult↗
PubMed1989

99Tcm-diastereomeric dimercaptosuccinic acid complexes: comparison of their biodistribution.

The biodistribution of two stereoisomeric 99Tcm complexes derived from diastereomeric dimercaptosuccinic acids (DMSA), 99Tcm-dl-DMSA and 99Tcm-meso-DMSA, was examined in sarcoma 180 tumour-bearing mice. The biodistribution pattern of meso-complex was not significantly different from 99Tc(V)m-DMSA, a new tumour imaging agent, while the dl-complex did not show the osteotropic property observed in meso- and 99Tc(V)m-DMSA complexes. The ratio of tumour to blood was superior for the 99Tcm-dl-DMSA (2.68) over the 99Tcm-meso-DMSA (1.25) at 3 h, and the ratio was reversed at 6 h, 3.13 to 4.28. The results indicate that dl-complex is of importance for the possible use in tumour imaging.

Animals↗
PubMed1989

Early isonitrile SPECT in acute myocardial infarction: feasibility and results before and after fibrinolysis.

Early 99Tcm-labelled methoxy-isobutyl-isonitrile (MIBI) SPECT was performed in 14 patients with suspected acute myocardial infarction (AMI). The radiopharmaceutical was administered immediately upon admission to the intensive care unit and before any diagnostic confirmation. Then, if decided, thrombolytic therapy was started. Cardiac imaging was performed 1 h later, and as there is no significant re-distribution, the pictures still showed the pre-treatment MIBI uptake. In three cases acute myocardial infarction was not confirmed. For one of them, the result was normal and this patient was ultimately considered to have had a transient ischaemic event. The two other cases had acute chest pain with a previous history of myocardial infarction (MI) and a pathological MIBI SPECT. In the 11 cases with confirmed first AMI significant perfusion defect was seen. For every patient a new MIBI injection with a control SPECT was repeated 72 h after admission. Eight patients were seen 1 h 15 min to 3 h 15 min after the onset of chest pain and had thrombolytic therapy. Defects were always in agreement with coronary angiography and 2D echocardiography performed in the same period. After thrombolysis, control SPECT showed no recovery in three cases, partial recovery in four, and nearly complete recovery in one. Using this technique, it was then possible to get high quality myocardial perfusion imaging without delaying treatment of AMI. This preliminary series suggests that MIBI SPECT may be useful in accurately showing the size and location of the immediate perfusion defect, and in assessing the response to emergency therapy of AMI, especially thrombolysis.

Adult↗
PubMed1989

Myocardial gated tomoscintigraphy with 99Tcm-methoxy-isobutyl-isonitrile (MIBI): regional and temporal activity curve analysis.

Myocardial gated tomoscintigraphy with hexakis-(2 methoxy-isobutyl-isonitrile) labelled with 99Tcm, is more suitable to resolve precisely the size of myocardial infarct than nongated 201Tl tomoscintigraphy. Gated tomography gives short axis slices at eight points in the cardiac cycle. A quantitative method to analyse heart wall activity and its motion is proposed. In two groups of patients, one with inferior infarct and the other with anterior infarct, the time-activity curves show a maximum in systole for healthy regions and a flattened curve in akinetic regions. Gated tomoscintigraphy assesses more accurately the size of the injured regions because there is no averaging between systolic and diastolic activity as in 201Tl tomoscintigraphy. This method should permit a better follow-up of patients with myocardial infarct.

Humans↗
PubMed1989

What is the optimal imaging time for 99Tcm-(V)-DMSA planar scintigraphy in the detection of squamous carcinoma? A comparative study in humans and in an animal tumour model.

99Tcm-(V)-DMSA is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. There have been, however, no studies to date evaluating its optimal imaging time for SCC. Seven patients were studied (six SCC; one nontumour) and seven rabbits (six with SCC, (17 tumours); one nontumour). For the human qualitative studies there was a 67% sensitivity at 2, 4 and 6 h with image quality being optimum at 4 h. Maximum quantitative uptake occurred between 2 and 4 h. For the rabbit qualitative studies the optimum imaging time was 4 h (92% sensitivity, 100% specificity) and maximum quantitative uptake occurred at between 1.5 and 5 h. Taking into account the human and rabbit qualitative and quantitative studies combined with the pharmacokinetics and biodistribution of 99Tcm-(V)-DMSA, the optimum imaging time of 99Tcm-(V)-DMSA in humans with SCC was between 2 and 4 h.

Aged↗
PubMed1990

Hepatic perfusion index in the diagnosis of overt metastatic colorectal cancer.

The hepatic perfusion index (HPI) was measured in 180 patients with colorectal cancer: 109 with primary colorectal cancer, 38 with suspected recurrent colorectal cancer and 33 following curative resection of colorectal cancer. In 21 patients with proven metastatic disease serial imaging studies were performed. HPI was determined using the peak of the left kidney time-activity curve to define the division of arterial and portal blood flow. HPI was elevated (greater than 0.37) in 54 of 115 patients (47%) with no evidence of hepatic metastases, 17 of 27 patients (63%) with hepatic metastases at initial presentation and 21 of 25 (84%) with metastatic disease detected during follow-up. Only 4 of 13 patients (31%) with local recurrence but no evidence of liver metastases had an elevated HPI. Serial imaging of patients with metastatic liver disease demonstrated a rising HPI with clinical disease progression in 18 of 21 patients (86%). This study confirms the association of an elevated HPI with hepatic metastases and suggests that a rising HPI in serial studies is associated with progression of disease but highlights the deficiency of one single HPI estimation in the identification of patients with overt hepatic metastases.

Colorectal Neoplasms↗
PubMed1990

Technetium-99m antimony sulphide colloid lymphoscintigraphy of the prostate by direct transrectal injection.

Laterality of prostatic lymphatic drainage was successfully assessed in nine patients with prostatic carcinoma after direct unilateral transrectal injections of 99Tcm-antimony sulphide colloid by Franzen needle. Pelvic lymphatic drainage was equally divided between ipsilateral, contralateral and bilateral patterns. The frequent observation of radiocolloid migration to contralateral lymph node groups in patients with prostate carcinoma, including those with primary disease localized clinically to a single lobe of the prostate, indicates the potential for contralateral pelvic lymph node metastases in this population. This finding may be important in determining the appropriate surgical staging and treatment of patients with prostate carcinoma. The clinical applicability of lymphoscintigraphy in the evaluation of metastatic spread and in lymph node biopsy planning requires further study.

Administration, Rectal↗
PubMed1991

Comparison of the myocardial distributions of 201Tl and 99Tcm-MIBI on SPECT images.

The distributions of 201Tl and 99Tcm-MIBI on stress images were quantitatively measured in a series of 15 patients presenting with documented coronary artery disease. Following two sequential, one-week apart, peak-exercise injections of either 74 MBq of 201Tl or 370 MBq of 99Tcm-MIBI, tomographic views of the myocardium were reconstructed and two thick, central short-axis sections were divided into nine sectors. A sector was considered as showing a defect if its relative activity was lower than 30, 40, 50 or 60% of the highest level of activity in the 18 sectors. Results demonstrate that there were more defects with 201Tl than with 99Tcm-MIBI. However, the difference disappeared if the inferior wall was not included. These results suggest that depth attenuation could be, at least partly, responsible for the higher rate of positive results observed in single photon emission computed tomography with 201Tl than with 99Tcm-MIBI.

Adult↗
PubMed1992

Lacrimal scintigraphy in the diagnosis of epiphora.

The value of lacrimal scintigraphy in the assessment of nasolacrimal duct obstruction was determined by comparing the results with syringing in 67 patients (83 eyes). As expected, of 28 lacrimal drainage systems which were obstructed on syringing, 23 (82%) had abnormalities of tear drainage on scintigraphy. However, in 55 lacrimal drainage systems that were patent on syringing, 19 (35%) were normal, but in 36 (65%) abnormalities not apparent on syringing were detected on scintigraphy. Thus scintigraphy is a very useful technique in the assessment of nasolacrimal duct obstruction particularly in systems patent on syringing. Since the site of obstruction can be determined, lacrimal scintigraphy can facilitate the planning of the appropriate surgery.

Humans↗
PubMed1992

99Tcm-MIBI single photon emission tomography (SPET) for detecting myocardial ischaemia and necrosis in patients with significant coronary artery disease.

The ability of 99Tcm-methoxyisobutylisonitrile (MIBI) single photon emission tomography (SPET) to detect myocardial ischaemia and necrosis was assessed in 56 patients (45 male, 11 female, aged 55 +/- 5 years), with clinically recognized ischaemic heart disease (IHD). All underwent coronary angiography (CA) and left ventriculography (LV). SPET images were obtained at rest and at peak exercise (Modified Bruce) 90 min after injection of 99Tcm-MIBI (650-850 MBq). Data were acquired in 30 min over 180 degrees (from 45 degrees RAO to 45 degrees LPO) with no correction for attenuation, using a 64 x 64 matrix. The presence of persistent (P) or reversible (R) perfusion defects (PD) was then correlated to the resting and exercise ECG and to the results of CA and LV. Of the 56 patients, 34 had reversible underperfusion (RPD), 46 persistent underperfusion (PPD) and 31 had both. The occurrence of RPD correlated well with the occurrence of exercise-induced ST segment depression and/or angina (27 patients of 34 patients, 79%) and with the presence of significant coronary artery disease (CAD) (33 of 44, 73%). In 45 of 46 patients (98%) PPD corresponded to akinetic or severely hypokinetic segments (LV) usually explored by ECG leads exhibiting diagnostic Q waves (42 of 46 patients, 91%). The scan was normal both at rest and after stress in four of 11 patients with no CAD, and in two of 45 patients with CAD. Finally, an abnormal resting scan was seen in seven of 11 patients with normal coronary arteries, of whom six had regional wall motion abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Variable portal circulation from inferior mesenteric vein assessed by per-rectal radionuclide administration.

The intrahepatic distribution of radioactivity after the per-rectal administration of 201T-chloride and/or 99Tcm-pertechnetate was investigated in 177 studies in 149 patients with no liver disease or diffuse liver disease and compared with that of 99Tcm-stannous (99Tcm-Sn) colloid scintigrams. The patients were classified into two groups: distribution of intrahepatic radioactivity of 201Tl and/or 99Tcm-pertechnetate scintigrams similar to (homogeneous) or different from (heterogeneous) that of 99Tcm-Sn-colloid scintigrams. The heterogeneous group was divided into three subgroups: increased radioactivity of the right lobe (right dominant pattern), increased radioactivity of the left lobe (left dominant pattern) and uneven distribution of radioactivity in both lobes (uneven pattern). Of the 80 patients in whom the studies were performed in the supine position at rest, 14 (17.5%) showed a heterogeneous pattern (8 right dominant, 4 left dominant, 2 uneven) and 66 (82.5%) a homogeneous pattern. In the 97 patients allowed free body movement, 6 (6.2%) showed a heterogeneous (1 right dominant, 5 left dominant) and 91 (93.8%) a homogeneous pattern. A significant difference in the incidence of heterogeneous distribution between the resting and free body movement groups was found (P < 0.05). One patient with a left dominant pattern after free body movement with 201Tl showed a right dominant pattern at rest in the 99Tcm-pertechnetate study. It is concluded that a heterogeneous intrahepatic distribution of inferior mesenteric vein blood is sometimes observed and that the distribution of portal vein blood flow seems to be affected by the patient's positioning and free body movement.

Administration, Rectal↗
PubMed1997

Index for predicting post-operative residual liver function by pre-operative dynamic liver SPET.

To predict residual liver function before hepatic resection, we devised a predictive index by combining clearance values with functional liver volume measured by liver dynamic single photon emission tomography (SPET). Forty-seven patients with liver disease underwent liver dynamic SPET with 99Tcm-Sn colloid before hepatic resection. There were no operation-related deaths. Three patients died from hepatic failure more than 1 month following the operation. Their predictive indices were 0.24, 0.33 and 0.34. When the predictive index was above 0.35, no patient had symptoms of hepatic failure or died. Our data suggest that when the predictive index is above 0.35, there is a low probability of hepatic failure after hepatectomy.

Adult↗
PubMed1998

The use of dual-isotope imaging to compare the gastrointestinal transit of food and pancreatic enzyme pellets in cystic fibrosis patients.

Cystic fibrosis patients require pancreatic enzyme supplements to aid food digestion. It is suspected that incorrect delivery of this enzyme may result in both significant malabsorption and the development of strictures in the proximal colon caused by the high-dose supplement reaching this region before the food. Investigations into the drug's delivery were performed using dual-isotope imaging; a method was developed to directly label the enteric-coated enzyme pellets with 111In, re-applying the enteric coating afterwards, and this was then ingested with a pancake meal labelled with 99Tcm-tin colloid. Consecutive image data, acquired over a period of > or = 4 h using a dual-headed gamma camera, were analysed to assess intestinal transit. In-vitro stability checks on these labelling techniques were encouraging, showing < 2% 99Tcm and < 7% 111In elution over 90 min in hydrochloric acid. In 5 of the 12 patients studied to date, the pellets were seen to pass through significantly faster than the food, with a mean difference in 50% gastric emptying time of greater than 93 min. The mean absolute difference in emptying time for all 12 patients was > 67 min. Thus, a technique has been developed to effectively radiolabel pancreatic enzyme pellets, and analysis of dual-isotope images using this preparation, together with radiolabelled solid food, has demonstrated significant differences in the transit of these two substances through the gastrointestinal tract of some cystic fibrosis patients.

Adolescent↗
PubMed1999

In vivo stability and metabolism of 99Tcm-labelled anti-CD4 monoclonal antibodies and Fab' fragments.

In a comparative study, the in vivo metabolic profile of 99Tcm-anti-CD4 monoclonal antibodies (MAb) and Fab' fragments (direct thiol-reduction method) was investigated in rats with adjuvant arthritis. Plasma samples were obtained 1, 4 and 15 h following intravenous injection and urine was collected over 15 h. The composition of the radiolabelled molecules was analysed by gel filtration chromatography. The profile of the complete MAb was as follows. (1) Serum: a predominant peak of 150 kDa (complete MAb; approximately 80%); three minor peaks of 125, 100 and 50 kDa (presumably H2L1, H2 and H1 chains; 14%); and two small peaks of approximately 1500 and 300 Da (presumably 99Tcm-glutathione and Cys-99Tcm-Cys; 5%). (2) Urine: minor peaks of 125, 100 and 50 kDa (15%), major peaks of 1500 and 300 Da (50%), and an additional 25-kDa peak (30%). The profile of the Fab' was as follows. (1) Serum: three minor peaks of 150 kDa [conceivably F(ab')2 plus soluble-CD4], 110 kDa [F(ab')2] and 95 kDa (Fab' plus soluble-CD4; together 30%); a predominant peak of 55 kDa (Fab'; 61%); and two minor peaks of 1500 and 300 Da (8%). (2) Urine: predominantly a 55 kDa (16%) and 1500 and 300 Da peaks (74%). Also, the anti-CD4 Fab' showed higher urine excretion and lower plasma levels than the complete anti-CD4 MAb, but still more favourable tissue-to-blood ratios following scintigraphy of the arthritic joints. Thus, the complex metabolic profile of the anti-CD4 Fab' does not appear to interfere with specific targeting of the inflamed synovial membrane.

Animals↗
PubMed1999

Visualization of functional improvement by 123I-IMP lung SPET after thromboendarterectomy for chronic pulmonary embolism.

We report on six patients with chronic pulmonary embolism who underwent 123I-IMP and 99Tcm-MAA lung SPET before and after thromboendarterectomy. 123I-IMP lung SPET can assess the viability of lung parenchyma, because it is a non-particulate agent that accumulates in the endothelial membranes of pulmonary capillaries. Chronic pulmonary thromboembolism accompanied by pulmonary hypertension has a poor prognosis that may be improved only by thromboendarterectomy. We compared 123I-IMP and 99Tcm-MAA lung SPET in terms of functional improvement after such surgery. After thromboendarterectomy, all six patients were functionally improved, according to the criteria of the New York Heart Association. The pre- and post-surgery percentage of vascular obstruction did not differ significantly with 99Tcm-MAA lung SPET (44.8 +/- 11.2% and 32.5 +/- 15.6% pre- and post-surgery, respectively). In contrast, 123I-IMP lung SPET revealed a significant pre- versus post-surgery difference (15.5 +/- 9.5% and 3.3 +/- 5.9% pre- and post-surgery, respectively). 123I-IMP lung SPET could be useful for evaluating thromboendarterectomy because pulmonary parenchymal viability owing to arterial microvasculature can be estimated.

Adult↗
PubMed2001

Post-elution concentration of 99TcmO4- by a single anion exchanger column: II. Preparation and evaluation of jumbo alumina column chromatographic generator for 99Tcm.

We report on the preparation and evaluation of a large size (jumbo) alumina column (approximately 40 g, 90 x 20 mm) chromatographic generator and post-elution concentration of 99Tcm using a single column of a weak anion exchanger. The generator was eluted with approximately 40 ml of a modified single salt buffer solution of 1:1 v/v 0.025 M or 0.05 M NH4OAc:0.7 M AcOH. This eluate was then passed through a small column of DEAE cellulose, a common weak anion exchanger, to trap 99TcmO4-, which was recovered by elution in 6 ml of normal saline. This amounts to a 5- to 7-fold increase in radioactive concentration (RAC) of 99Tcm, when compared to the RAC on direct elution with normal saline from the same jumbo alumina column generator. The overall yield of 99Tcm was in the range of 70-90%. 99Mo breakthrough was 10(-3)-10(-4)%, radiochemical purity was > 98%, and chemical purity, in terms of Al and Mo content, < 10 ppm each. The compatibility of pertechnetate obtained by this method for preparing 99Tcm labelled formulations such as Tc-MDP and 99Tcm-ethyl cysteinate dimer was found to be satisfactory. These promising results open up the feasibility of using (n, gamma) 99Mo adsorbed on a large (40-60 g) alumina column as a relatively more user-friendly source of 99Tcm in comparison to methyl ethyl ketone extraction, and as a producer-friendly process in comparison to the zirconium molybdate gel method.

Aluminum Oxide↗