Lung ventilation studies with technetium-99m Pseudogas.
(57/98)
Technetium-99m Pseudogas is an ultrafine near monodisperse aerosol of 0.12-microgram diam particle size. This report describes initial clinical experiences with 27 patients referred for investigation of suspected pulmonary embolism, and in whom Pseudogas ventilation images were compared with a high quality commercial aerosol. An additional group of ten patients with severe COPD was examined in a comparative trial of Pseudogas with 81mKr. Pseudogas was better than a conventional aerosol in reaching a diagnosis of pulmonary embolism using a simple blinded comparison with coded images. In addition, bronchial deposition was minimal unless COPD was severe. Moderately well patients had no difficulty inhaling the necessary activity in one or two breaths, and even severely ill and frail aged persons could accomplish the passive breathing maneuver in less than a minute. Clearance of Pseudogas was directly to the systemic circulation with a half-time of 10 min in normal subjects extending up to 100 min in patients with airways disease. (+info)
Prognostic value of axillary lymphoscintigraphy in breast carcinoma patients.
(58/98)
Axillary lymphoscintigraphy (AxLS) with bilateral interdigital injection of [99mTc]antimony sulfide colloid carried out concurrently with internal mammary lymphoscintigraphy in 488 patients with breast carcinoma was evaluated. Patterns of radiocolloid distribution within the ipsilateral axilla and supraclavicular fossa were compared with similar features on the contralateral side to determine whether image characteristics are significantly disrupted by prior surgery, reflect the presence of metastases, and can predict treatment failure. Interpretive criteria for AxLS were refined after correlation of the identified image components with clinical parameters including axillary surgery, lymph node histology and relapse within a follow-up period of 2 years from the study. Results indicate that AxLS is at least as accurate as clinical assessment and provides data predictive of relapse to complement axillary lymph node status although the technique cannot presently replace lymph node sampling for patient staging. (+info)
Lymphoscintigraphy in lymphedema: an aid to microsurgery.
(59/98)
The role of lymphoscintigraphy, performed with 99mTc-labeled antimony sulfur colloid, in the diagnosis of lymphedema and as a test for selection of patients for microvascular operation was evaluated in 32 patients with primary and secondary lymphedema and four patients with other causes of leg edema. Lymphoscintigraphy clearly demonstrated if edema was of lymphatic origin. Five different image patterns were identified; abnormal image patterns could not be predicted from clinical history or physical findings. Quantitative evaluation of removal of the radioactive colloid from the injection site and appearance in lymph node sites and liver was of limited usefulness. Nine patients underwent various surgical procedures before or after lymphoscintigraphy. Lympho-venous anastomoses were possible only in patients who had patent lymph channels visible on lymphoscintigrams. Based on initial experience, lymphoscintigraphy seems to be useful to select patients for microvascular operation. (+info)
Pharmacokinetics of 99mTc(Sn)- and 131I-labeled anti-carcinoembryonic antigen monoclonal antibody fragments in nude mice.
(60/98)
The biodistribution, radioimmunoimaging, and high pressure liquid chromatography activity profiles of 99mTc(Sn) and 131I-labeled anti-carcinoembryonic antigen monoclonal antibody fragments were compared. Nude mice, bearing specific (colon carcinoma, LS174T) and nonspecific (pancreatic carcinoma, MIA) xenografts were given injections of the respective radiolabeled antibody fragments and also of irrelevant 125I-labeled antibody fragments (MOPC-21). The animals were imaged at 24 h after being given injections, they were sacrificed, and biodistribution studies were performed. Results of the study showed high kidney uptake [48.6% injected dose (ID)/g +/- 8.1% (SD)] and low tumor uptake (1.5% ID/g +/- 0.6%) for 99mTc(Sn)-labeled fragments and higher uptake (4.4% ID/g +/- 0.6%) for 131I-labeled fragments, resulting in a higher localization index for the radioiodinated monoclonal antibody fragments. Imaging results showed good tumor visualization at 24 h after injection for the 131I-labeled fragments and poor tumor visualization with predominant kidney uptake for 99mTc(Sn)-labeled fragments. After radiolabeling, high pressure liquid chromatography analysis indicated that 131I was primarily associated with F(ab')2 fragments, whereas 99mTc was mostly associated with Fab' fragments. (+info)
Detection of reticulo-endothelial blockade with low-dose test agent.
(61/98)
Blood clearance and organ extraction of a low-dose reticulo-endothelial test agent, technetium labelled tin colloid (TTC), was measured in groups of rabbits pretreated with reticulo-endothelial blocking agents. Electron microscopy and ultrastructure analysis confirmed that Kupffer cells extracted TTC. Pretreatment with silica caused reduced Kupffer cell uptake and spillover of TTC into the spleen. Pretreatment with sheep red cells caused reduced Kupffer cell uptake and reduced splenic uptake but anti-fibronectin caused only reduced splenic uptake of TTC. TTC is a suitable agent to detect alteration of reticulo-endothelial function. (+info)
Clinical comparison of two radiocolloids for internal mammary lymphoscintigraphy.
(62/98)
Recent studies suggest that 99mTc-labeled radiocolloid (SC) compounded with hydrogen sulfide can be used to visualize lymph channels and nodes. Our study prospectively compared SC with 99mTc antimony sulfide (SbS) colloid, in 28 patients undergoing internal mammary lymphoscintigraphy. Images were recorded on a scintillation camera and computer at 0.5, 1.0, and 3.0 hr. Quantitative analysis included assessment of percent (%) injected dose in nodes, the percent remaining at the injection site, and the relative intensity of the most cephalad node compared to a 57Co standard. The mean (means) % injected dose of both radiocolloids within visualized nodes was less than 1% at each time interval, with no significant differences between means's. The means % injected dose remaining at the injection site at 3.0 hr was 83 for SbS and 76 for SC not statistically significant (N.S.). The means of the ratio of counts within the most cephalad node at 3.0 hr to counts within a 57Co standard was 0.98 for SbS and 1.03 for SC (N.S.). Clinical assessment of number of nodes visualized and extent of radiocolloid migration showed no difference between the two agents. The biological and clinical parameters for the two colloids appear similar when used for internal mammary lymphoscintigraphy. (+info)
A comparison of two technetium-99m-labeled radiopharmaceuticals for lymphoscintigraphy: concise communication.
(63/98)
A comparison of stannous phytate and antimony sulfide colloid, both labeled with Tc-99m, was conducted during the performance of internal mammary lymphoscintigraphy in 46 patients. Thirteen of these patients were randomized to receive both radiotracers in two consecutive studies. The results indicated a statistical difference between agents; Tc-99m antimony sulfide allowed visualization of a greater number of more intense nodes, better delineation of the total length of the internal mammary lymph-node chain, and a more consistent visualization of supraclavicular nodes. Although previously published animal data suggest utility of Tc-99m stannous phytate for lymph-node imaging, Tc-99m antimony sulfide was shown in this clinical comparison to provide a more reliable representation of lymph-node anatomy. (+info)
The use of radionuclides in the investigation of conjoined twins.
(64/98)
Three sets of thoraco-omphalopagous conjoined twins were investigated. The clinical findings indicated a complex shared heart in two sets, and separate cardiovascular systems in the other. These assessments were confirmed by dynamic imaging after bolus injection of Tc-99m(Sn)colloid or Tc-99m millimicrospheres. Static images were then used to establish the configurations of the shared livers. The results of these studies were in keeping with the angiographic and autopsy findings in the two sets with complex cardiac anomalies and with the surgical findings during successful separation of the third set. (+info)