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Biomedical subjects

K Boddy

Publications and source records attributed to K Boddy.

At least 19 recordsLinked to original sources
PubMed1991

Intercomparison of whole-body counters using a multinuclide calibration phantom.

Whole-body counters in the UK have been compared using a multinuclide anthropomorphic phantom. A standard Bush phantom was modified by inserting channels into the long axis of each section. Radionuclide sources sealed in a urea-formaldehyde polymer were then inserted into the channels to simulate distributions of radioactivity in a human. The phantom was taken to 10 whole-body counters in the UK and estimates of 134Cs, 137Cs and 40K were obtained both separately and as mixtures. Results showed close agreement between the median estimates and the known activities. The technique also allowed diagnosis of particular problems in calibration for several of the counters.

Calibration↗
PubMed1989

Autoregressive spectral estimation of fetal breathing movement.

Fetal breathing movement (FBM) in utero may be an indicator of fetal health. This paper provides a second-by-second estimate of FBM rate. In the absence of a statistical model for the fetal breathing movement, block data structured autoregressive spectral estimation is used. The optimum tapered Burg algorithm provides a minimum variance breathing rate estimate from a short block of data. The data were recorded using a PVDF (PolyVinyliDeneFluoride) transducer which picks up maternal abdominal wall movements. A peak tracking algorithm is used to extract the fetal breathing rate. Results from these signals are presented in graphical form. Further analysis of the fetal breathing rate has revealed periodicities, similar to that observed in the fetal heart rate.

Algorithms↗
PubMed1987

Fasting hyperinsulinemic hypoglycemia after ritodrine therapy for premature labor.

A 26-year-old woman with a triplet pregnancy was treated prophylactically with ritodrine beginning at 15 weeks' gestation. At 32 weeks, she was admitted in preterm labor, and over the next 12 days received high-dose oral or intravenous ritodrine. Three female infants were delivered by cesarean section after spontaneous rupture of the membranes. Postoperatively, she developed profound hypoglycemia with inappropriately high insulin levels. Maternal hypoglycemia after ritodrine therapy in pregnancy has not been reported previously. We discuss possible mechanisms.

Adult↗
PubMed1979

Fetal breathing: its physiologic and clinical implications.

The respiratory movements the human fetus makes in utero can be detected and used as a valuable aid in determining fetal well-being. Their presence or absence, amplitude, and duration can all provide important information. Their absence, however, does not carry a poor prognosis unless other indices of fetal status, such as the nonstress test and oxytocin-challenge contraction-stress test, are also abnormal at the same time.

Animals↗
PubMed1979

Whole body elemental composition during drug treatment of rheumatoid arthritis: a preliminary study.

Thirty-two female patients with rheumatoid arthritis were divided into 3 groups and treated for 6 months with prednisolone, depot tetracosactrin, or indomethacin. Their whole body content of calcium, phosphorus, and nitrogen was measured before and after 3 and 6 months' treatment by in-vivo neutron activation analysis. No significant changes in these body elements were observed as a result of the treatments. The average amounts of calcium, phosphorus, and nitrogen were lower than normal in these patients, a finding consistent with the frequent observation of osteoporosis and muscle wasting in rheumatoid arthritis.

Adult↗
PubMed1978

Concurrent estimation of total body and exchangeable body sodium in hypertension.

1. Total-body neutron-activation analysis in vivo was carried out in 11 hypertensive subjects to measure simultaneously the total body content of sodium, chlorine, calcium, phosphorus and nitrogen. 2. There was a highly significant correlation between total body sodium measured by activation analysis and total exchangeable sodium measured by a standard isotope-dilution technique (r = 0.92, P less than 0.001). Exchangeable sodium averaged 80.3% of total body sodium. 3. The measured values of chlorine, calcium, phosphorus and nitrogen were similar to those for healthy subjects reported by others. 4. Activation analysis in vivo appears promising as an additional tool for investigating sodium metabolism in hypertension, as it is the only method available for determining the total body content of this element. The radiation dose (1 rem) is sufficiently low to permit repeated measurements in the same subject.

Adult↗
PubMed1978

Neutron uniformity studies related to clinical total body in vivo neutron activation analysis.

Methods of assessing the uniformity of thermal and fast neutron fluence in relation to total body in vivo neutron activation analysis are described. Results are presented for 14 MeV neutrons emitted by sealed tube generators housed in a massive concrete shield, representing a substantial source of neutrons degraded in energy. Optimisation of conditions for patient irradiations is discussed and it is shown that acceptable uniformity of fluence can be achieved with little or no premoderation of the incident neutrons.

Activation Analysis↗
PubMed1978

Calibration and evaluation of a system of total body in vivo activation analysis using 14 MeV neutrons.

A system has been established for determining the total body contents of calcium, phosphorus, sodium, chlorine and nitrogen by neutron activation analysis using sealed-tube neutron generators and a shadow-shield whole-body counter. The system was calibrated using three anthropomorphic phantoms of different sizes, filled with various mixtures of the activatable elements in amounts similar to those in man. The reproducibility determined from replicate measurements, was on average +/- 2.9% (SD). The average uncertainty in absolute measurements was estimated to be +/- 4.2% (68% confidence interval).

Activation Analysis↗
PubMed1978

A two-way scanning method for total body in vivo neutron activation analysis.

When determining the total body content of many elements by neutron activation analysis, irradiation and whole body counting by scanning along the length of the body has significant advantages. A neutron source of lower output and a whole body counter using smaller detectors and shielding (than otherwise needed) can provide a high, uniform response for many elements throughout the body. This was previously achieved by making the speed and direction of scanning identical in irradiation and counting (one-way scanning). A simple theoretical model for scanned irradiation and counting is described. The model is used to show that a scanning regime in which both scanning directions are used (two-way scanning) can provide acceptably uniform response for elements having induced activities of a wide range of half-life. This is supported by measurements made using an existing scanning facility for total body in vivo neutron activation analysis. The two-way scanning regime offers the advantages of increased patient comfort, simpler operation and more efficient use of the time available for counting induced activity.

Activation Analysis↗
PubMed1978

Magnesium metabolism in patients with coronary heart disease.

1. The oral absorption of magnesium, its myocardial uptake and exchangeable magnesium have been studied in patients with coronary heart disease and controls using the radioactive isotope magnesium-28. 2. No significant difference in oral absorption or myocardial uptake was found between patients and controls. 3. The exchangeable magnesium per kg body weight was significantly lower in the patients than in the controls.

Adult↗