A solid dynamic phantom has been constructed, which allows quantitative measurements of the signal-to-noise ratios in processed images from digital subtraction angiography (DSA) units. Profiles of silicone rubber placed in concentric circles on a plate which is rotated in the image plane generates bolus curves with five different transit times in each examination. The phantom is suited for measurement on DSA units working with matched or recursive filtering.

Angiography, Digital Subtraction↗

PubMedDate not supplied

Quantitative single photon emission computed tomography applied to a comparison of propanetetraphosphonate and albumin colloid for liver and spleen scintigraphy.

A clinical application of a previously developed technique for absolute quantitation of organ uptake of radioactivity is presented. The method, which is based on single photon emission computed tomography involving correction for scattering and attenuation of photons, enables an accurate in vivo determination of the amount of administered activity taken up in a specific organ. The technique was applied to a comparative clinical trial between propanetetraphosphonate and albumin colloid for liver and spleen scintigraphy. The mean uptake of the liver was 73 +/- 9 per cent using propanetetraphosphonate and 63 +/- 10 per cent using albumin colloid. The corresponding figures for the spleen were 6 +/- 3 and 9 +/- 4 per cent, respectively. The activity concentration of the different lobes of the liver, bone marrow and soft tissue was also estimated. Phantom studies showed that the total uptake in the liver could be determined with an accuracy of about 6 per cent. The accuracy of the clinical examinations was estimated to about 10 per cent.

Adult↗

PubMedDate not supplied

Immune functions in melanoma patients during treatment with interferon [HuIFN-alpha (Le)] alone or in combination with cimetidine.

While leukocyte interferon was found therapeutically ineffective in a series of 20 patients with metastatic malignant melanoma, subsequent combination treatment with interferon and cimetidine induced 5 complete and 1 partial tumour remissions. Prior to interferon therapy initiation, regressor patients demonstrated a significantly greater ability to mediate antibody-dependent cellular cytotoxicity than progressor patients and also tended to have higher natural killer-cell activity. These differences were more pronounced following in vitro exposure of effector cells to interferon alone or in combination with cimetidine. During therapy the differences decreased to statistically nonsignificant levels. The number of immunoglobulin producing cells and lymphocyte proliferative responses to Con A were found to increase in both patient groups after interferon therapy initiation; but this augmentation vanished gradually upon combined treatment with cimetidine. A gradual decrease of the number of T lymphocytes and granulocytes was also recorded. None of the demonstrated alterations in the activities of circulating lymphocytes appears to be a relevant correlate to the efficacy of combined therapy compared to interferon alone.

Antibody-Dependent Cell Cytotoxicity↗