Nuclear medicine communications
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The relationship between the concentration of tissue glutathione (GSH) content and uptake of 99Tcm HMPAO in Sprague Dawley rats was investigated. The GSH content of rat tissue was depleted with diethyl-maleate (DEM) and the ratio of GSH in control to GSH depleted rat was approximately twice that in the brain, liver, kidney, spleen and lung. ⋯ The apparent increase of radioactivity in the liver was due to longer retention of 99Tcm HMPAO. This longer retention was due to stasis of bile flow as confirmed by subsequent experiments in which cholecystokinin (CCK) was administered to GSH depleted rats and compared to the uptake of GSH depleted rats without injection of CCK.
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Comparative Study
Gastric emptying after partial gastrectomy without vagotomy with primary Roux-en-Y or Billroth II anastomosis.
Several clinical studies have indicated that gastric emptying is delayed in patients with Roux-en-Y biliary diversion with vagotomy. In order to determine whether Roux-en-Y diversion without vagotomy also induces delayed gastric emptying, we have compared the effect of gastrectomy without vagotomy with either Billroth II or Roux-en-Y anastomosis on gastric emptying of a liquid and solid meal in 22 peptic ulcer patients. The emptying half-times (t1/2) for solid food were not significantly different, 54; 24-122 min (median and range) in the 11 patients with Billroth II gastrectomy, 68; 44-189 min in the 11 patients with Roux-en-Y gastrectomy, and 83; 27-114 min in 11 normal control subjects. ⋯ The t1/2's for the fluid meal were similar, 7; 4-49 min after Billroth II gastrectomy, 8; 4-32 min after Roux-en-Y gastrectomy, and 9; 3-20 min in the control subjects. In all subjects the lag phase for the fluid meal was very short, ranging from 0 to 3 min. It is concluded that Roux-en-Y diversion per se does not delay gastric emptying in man.
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Comparative Study
99Tcm-HMPAO labelled leucocytes: comparison with 111In-tropolonate labelled granulocytes.
The lipophilic complex, 99Tcm-hexamethylpropyleneamine oxime (HMPAO) is an efficient leucocyte label, and labels granulocytes with more stability than mononuclear leucocytes. The recovery of 99Tcm-HMPAO granulocytes, expressed as the percentage of injected granulocyte-associated activity circulating as granulocyte-associated activity 40-45 min after injection, was 37% (S. E. 3%), similar to the recovery of 111In-labelled granulocytes isolated and labelled in plasma using tropolone. ⋯ Clinical information given by the two agents was similar in 27 of 30 patients who received both. Of the three who gave different information, one received 111In-labelled granulocytes which were considered to be functionally suboptimal and two, with inflammatory bowel disease, showed different distributions of abnormal bowel activity. We conclude that with respect to granulocyte kinetics and clinical data, 99Tcm-HMPAO labelled leucocytes are comparable with 111In-tropolonate labelled granulocytes.
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Comparative Study
Comparison of 99Tcm-HMPAO and 111In-oxine labelled granulocytes in man: first clinical results.
The in vitro and in vivo behaviour of 99Tcm-HMPAO (hexamethylpropyleneamineoxime) (n = 12) and 111In-oxine (n = 11) labelled granulocytes, isolated by density-gradient centrifugation (Metrizamide/plasma gradients), was compared in patients with suspected inflammatory diseases. The in vitro elution of both labels and the viability of the labelled cells (99Tcm, 98.5%; 111In, 96.5%) was comparable but the labelling efficiency was different (99Tcm, 44 +/- 13%; 111In, 72.5 +/- 5.5%). In vivo, the lung (t1/2 max: 7.7 min), liver and spleen perfusion patterns were nearly identical; the image quality for detail in 99Tcm scans was superior to 111In images. ⋯ The recommended best imaging times for abdominal and retroperitoneal inflammations are 30 min to 2 h after injection. Late scans in septic prosthetic joints have disproportionate long acquisition times. As a potential cell labelling compound, 99Tcm-HMPAO has a promising future in comparison to 111In scans because of the good availability of 99Tcm, the image quality and the lower radiation exposure to the patient when lower activities for the early diagnosis of abdominal inflammatory diseases are reinjected.
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Stationary and nonstationary finite-impulse-response (FIR) implementations of the count-dependent Metz filter were investigated in this study. Filter size was observed to be an important variable controlling image quality. For Metz filtering of 128 X 128 pixel images at least a 15 X 15 term FIR filter was deemed necessary. ⋯ In a limited comparison of 'tumor' detection with stationary and nonstationary FIR filtering all of the Metz filtering techniques showed a significant improvement in detection when compared to the unprocessed images. However, no significant difference was observed between the stationary and nonstationary Metz filtering techniques. Thus, for Metz filters optimized solely on the basis of count, nonstationary FIR filtering does not seem to offer an advantage when compared to stationary filtering.