Axial resolution and the value of interpolating scan in multislice positron computed tomography.

We have calculated the aperture function of a positron computed tomograph (PCT) with computer simulation, and evaluated the axial resolution of a multislice PCT, Positologica III, both theoretically and experimentally. The axial point spread function (PSF) was approximately a triangle at or near the center of the field, and the sensitivity for the slice decreased significantly as the source moved away off the image plane. Accordingly, there were low sensitivity areas between an in-plane and the adjacent cross-plane.

In vivo kinetics and thrombus accumulation of 67Ga-labeled urokinase.

Highly purified high and low molecular weight urokinase (H-UK and L-UK) were labeled with 67Ga using deferoxamine (DF) as a bifunctional chelating agent. The labeling efficiency was 91.7% for the H-UK, and 90.

[125I] radioiodinated metaraminol: a new platelet-specific labeling agent.

In our search for a platelet-specific labeling agent, metaraminol (MA), a low-toxic pharmaceutical for the treatment of hypotension and cardiogenic shock, attracted our attention. Its active incorporation and accumulation by platelets have been recognized. At first, the preparation of 125I radioiodinated metaraminol (125I-MA) was carried out using the chloramine-T method.

Clinical application of the 10-MHz electronic linear array scanner.

A 10-MHz electronic linear array real-time scanner was developed. The axial resolution was 0.26 mm at the -20dB ring down point.

Iron(III)-nitrilotriacetate: an agent for reducing the time interval of tumor imaging with gallium citrate.

Increasing interest in the short-lived radionuclide 68Ga (t1/2: 68.2 min) has revived basic studies of gallium radiopharmaceuticals. Ga-citrate (Ga-cit), described as a polynuclear complex, possesses great affinity for tumor cells but is also bound by blood transferrin (Tf).

Accumulation of Tc-99m methylene diphosphonate in calcified metastatic lesions of the liver from colonic carcinoma. Comparison with calcification on X-ray computed tomogram.

Abnormal accumulation of Tc-99m MDP in two metastatic lesions of the liver was observed in a patient with resected colon carcinoma. Single-photon emission computed tomography (SPECT) revealed characteristic marginal accumulation of Tc-99m MDP in both of those metastatic lesions. X-ray CT showed the corresponding marginal calcification in one of the metastases, but no apparent calcification was observed in the other lesion.

The design of a pentavalent 99mTc-dimercaptosuccinate complex as a tumor imaging agent.

In our search for a technetium-tumor seeking agent, the chemical characteristic of polynuclear Ga-citrate attracted our attention. On this basis, we selected the ligand dimercaptosuccinic acid (DMS) and appropriate labeling conditions in the design of 99mTc(V)-DMS. Chemical characterization was performed by thin layer chromatography, electrophoresis, Sephadex column chromatography and spectrophotometric studies at the chemical concentration (99Tc).

Is ECT imaging with Tc(V)-99m dimercaptosuccinic acid useful to detect lung metastases of osteosarcoma?

ECT imaging, using Tc(V)-99m dimercaptosuccinic acid [Tc(V)-DMS] was performed in two patients with lung metastasis of osteosarcoma, and the results were compared with those of CT scan. Clear accumulation of Tc(V)-DMS was recognized in all cases in the same area that CT scans demonstrated. Tc(V)-DMS was labeled under optimal pH 8, had very low SnCl2 concentrations, an equilibrium between a stable form and a dissociated form of anion TcO4(3-) structurally similar to PO4(3-), and was postulated for tumor uptake.

Improved detection of myocardial infarction by emission computed tomography with thallium-201. Relation to infarct size.

Emission computed tomography with thallium-201 was compared with planar imaging in its ability to detect myocardial infarctions of various sizes four weeks after the onset. Tomography was performed after planar imaging at rest in 160 patients with a first myocardial infarction, in whom infarct size was prospectively estimated by the peak value of creatine kinase activity at the time of the acute episode and in 39 patients without infarction. The planar images and the transaxial, short axial, and long axial tomograms were interpreted qualitatively.

Stress thallium-201 transaxial emission computed tomography: quantitative versus qualitative analysis for evaluation of coronary artery disease.

Stress thallium-201 myocardial distribution was quantitatively evaluated by emission transaxial tomography in 104 patients who underwent coronary arteriography. The initial uptake and percent washout of thallium were assessed by the circumferential profile curves of the three short-axis sections and one middle right anterior oblique long-axis section. This quantitative tomographic analysis showed abnormal distribution in all but two patients (98%) with coronary artery disease, whereas qualitative analysis showed abnormality in 76 of the patients (93%).

Procurement and biological significance of pure 11C-glucose.

Biological significance of 11C-glucose purity has been a controversial matter. In order to understand the contribution of impurities contained in the photosynthetic 11C-glucose, its analysis and biodistribution in mice was studied. Studies indicated the interference of impurities, particularly 11C-fructose in the injectate, with the quantitative evaluation of glucose metabolic rate in brain.

Imaging of soft tissue tumors with Tc(V)-99m dimercaptosuccinic acid. A new tumor-seeking agent.

Tumor scintigraphy, using Tc(V)-99m dimercaptosuccinic acid (Tc(V)-DMS) was performed in 58 patients with soft tissue tumors, and the results were compared with that of Ga-67 citrate. Tc(V)-DMS was found to have a sensitivity of 90% for malignant tumors including aggressive fibromatosis compared to that of Ga-67 citrate, which was 56%. However, the specificity of Tc(V)-DMS for these tumors was 71% but with Ga-67 citrate the specificity was 80%.

Computed tomography of calcified gastric carcinoma.

The CT findings in a case of calcified gastric carcinoma of the mucin-producing type are described. These findings include localized thickening of the gastric wall and multiple tiny calcific nodules within it.