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Biomedical subjects

N J Brown

Publications and source records attributed to N J Brown.

14 recordsLinked to original sources
PubMed1979

Mobile gamma cameras and 99mTc-labelled phosphates in acute myocardial infarction.

99mTc-labelled phosphates (PyP, IDP and MDP) were compared for their usefulness for the diagnosis of myocardial infarction. The results indicated the superiority of 99mTc-labelled imidodiphosphonate over the other 99mTc-labelled phosphates. At the same time, two mobile gamma cameras were compared with respect to their instrumental characteristics and clinical versalitity and their advantages and disadvantages are reported.

Diphosphates↗
PubMed1979

A new transverse-section brain imager for single-gamma emitters.

Physical and clinical data on a new emission transverse-section scanner are given. Comparative data from an earlier tomoscanner and a rotating gamma-camera system yield the following information for the three imagers. Resolution at the center of the field is 9 mm for this tomoscanner, 18 mm for the earlier tomoscanner, and 11 mm for the rotating camera; sensitivity (cps/muCi-ml) 36K, 15.4K, 1.9K; crystal area (cm2) 3096, 619, 490, respectively. The quantification of images is discussed. Clinical emission section scans of the brain, liver, chest and skull are presented and discussed. Forty brain scans were analyzed in conjunction with x-ray transmission tomography. No false positives were found. From a total of 15 lesions seen by the CT x-ray scanner, 14 were detected by the emission tomographic scanner, 12 by standard gamma-camera imaging. One false negative case (cyst) was seen by the transmission x-ray scanner but not by the emission scanner.

Abdomen↗
PubMed1978

Validation of "transit renography" for the determination of the intrarenal distribution of plasma flow: comparison with the microsphere method in the anaesthetized rabbit and pig.

1. The spectrum of transit times of sodium o-iodohippurate (Hippuran) through the kidney can be derived from an 131I- (or 123I-) labelled Hippuran renogram by deconvolution. In the rabbit and pig, as has previously been shown in man, the frequency distribution curve for the transit times was bimodal. Since the transit time is likely to be proportional to the nephron length, the area of the first mode is likely to represent plasma flow to the shorter outer cortical nephrons whereas the delayed mode represents flow to the long juxtamedullary nephrons. 2. This interpretation was tested by simultaneously comparing renography with the microsphere method of measuring intrarenal plasma flow distribution in 12 rabbits and two pigs with a variety of anaesthetics. A close agreement was found between both methods for the percentage of plasma flow distributed to the outer cortical nephrons, thus supporting the use of "transit renography" to determine the intrarenal distribution of plasma flow.

Anesthetics↗
PubMed1978

99mTc-imidodiphosphonate: a superior radio-pharmaceutical for in vivo positive myocardial infarct imaging. II: Clinical data.

99mTc-Imidodiphosphonate was investigated as a new myocardial infarct imaging agent. In the acute phase, 50 patients admitted to the coronary care unit were serially scanned over a period of 7 days. A mobile gamma camera linked on line to a remote data processor was used. Because of higher uptake in infarcted myocardium and faster blood clearance, superior images than those recorded with 99mTc-pyrophosphate were obtained. Its ease of preparation, low cost, and favourable dosimetry (because of its label with conventional 99mTc) transforms this agent into the present radiopharmaceutical of choice for acute infarct imaging in particular if sizing and follow-up is intended versus time and type of treatment. In this series, no false positive cases were seen. The sensitivity of the method in the detection of full thickness myocardial infarction was 95%. It dropped to 70% in the detection of subendocardial infarction. However, some of these apparent false negative cases may reflect severe ischaemia without infarction. It is postulated that this discrimination may not always be realistic.

Diphosphonates↗
PubMed1977

A non-invasive test for receptor binding applied to nephrogenic diabetes insipidus.

Studies in animals have determined the importance of specific receptors to the action of many hormones and drugs. In man, a non-invasive external counting technique has been used and absence of receptor function has been demonstrated in a patient with nephrogenic diabetes insipidus using radioactively labelled arginine vasopressin. This is in contrast to the findings in a patient with pituitary diabetes insipidus and a normal control. These results suggest a model for the study of hormone and drug kinetics in man avoiding multiple samplings of biological fluids.

Adult↗
PubMed1977

High-quality, high-throughput, early whole-body bone scanning.

99mTc-IDP allows for high-quality, high-throughput and early whole-body bone scanning. Whole-body bone scans obtained at 30 min after intravenous administration of the tracer were compared with the standard and delayed 180 min p.i images. A subtraction technique allowed for the anlysis of the 30 min scans and it was found that in both types of investigation the same clinical information was present. This procedure will therefore increase considerably the throughput of whole-body bone scans in a busy department of nuclear medicine. It is however inadequate for detailed analysis of the skeleton (evaluation of benign bone disease).

Adult↗