Biomedical subjects

John G West

Publications and source records attributed to John G West.

3 recordsLinked to original sources

PubMed2006

Wool Base determination using dual energy X-ray absorptiometry (DEXA).

An industry grade dual energy X-ray absorptiometry (DEXA) scanner was calibrated for Wool Base determination. The calibration used 201 Crossbred and Merino wool samples, and a further 72 samples to validate the calibration. The prediction correlation had the smallest residual standard deviation (RSD) when the independently measured mean fibre diameter (MFD) was included in the multiple regression analysis. Best results were achieved when separate calibrations were used for individual wool breeds. The RSD for the Merino calibration set of 44 samples was 1.88, when the MFD was included in the regression, and 2.1 without. The RSD for 144 Crossbred samples was 1.73 including the MFD, and 2.59 without. The validation trial with 46 Crossbred and 24 Merino wool samples resulted in RSD of 2.35 and 2.23, respectively. An excellent DEXA repeatability was achieved at a standard deviation of approximately 0.2%. Improvement of the calibration is expected from concurrent laboratory testing and scanning. The research shows the promising potential for DEXA as a tool to determine Wool Base.

Absorptiometry, Photon↗

PubMed2005

Comparing neutron and X-ray-based dual beam gauges for characterising industrial organic-based materials.

Comparisons are made of the neutron gamma transmission (NEUGAT) and dual energy X-ray absorption (DEXA) methods of measuring the composition of organic-based industrial products. A simple model is developed to allow comparisons to be made particularly of the measurement precision and the industrial performance. These gauges have similar applications but the latter gauge is shown to be more suitable for high and variable product throughputs. X-ray tube source and detector combinations provide higher beam fluxes, superior imaging and require less bulky shielding.

Journal Article↗

PubMedDate not supplied

Risk of angiosarcoma following breast conservation: a clinical alert.

Approximately 100 cases of angiosarcoma following breast-conserving therapy have been reported. The prevalence of angiosarcoma following breast conservation has not been accurately established and optimal treatment has not been defined. The goal of this article is to clarify both issues. The Fisher's exact test was used to compare the prevalence of postirradiation angiosarcoma seen in our private practice to the prevalence reported from the two largest national database studies. A literature review was performed to determine optimal treatment guidelines. The results of the comparison indicated that the prevalence of postirradiation angiosarcoma seen in our practice was significantly higher than that reported in the two national database studies at p-values of 0.0124 and 0.0080. Also, results from the literature review suggest that early detection and aggressive treatment lead to improved outcomes. The data are insufficient to draw firm conclusions, but suggest that the current literature underestimates the prevalence of angiosarcoma following breast-conserving therapy. Since elderly women derive less benefit from radiation and may be more prone to develop postirradiation angiosarcoma, confirmation of our findings could lead to a reappraisal of the management of elderly patients with early stage breast cancer.

Age Factors↗