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Biomedical subjects

J R Prince

Publications and source records attributed to J R Prince.

26 records · Page 2Linked to original sources
PubMed1979

An evaluation of the 24-hour RAIU test performed with an Anger camera and a pinhole collimator.

RAIU measurements obtained with a conventional thyroid uptake probe have been compared with those obtained with an Anger camera and a pinhole collimator. Although the field distribution for the pinhole collimator deviates markedly from the IAEA recommendations, the group data from the comparative measurements in this series were identical, with a confidence level of 99%. However, in several cases the data from differing measurement regimes for individuals varied markedly.

Humans↗
PubMedDate not supplied

Bootstrap sensitometry for nuclear medicine.

A full radioscintigraphic monitor/film system sensitometric curve has been obtained utilizing a bootstrap technique in which individual characteristic curve segments, obtained from stepwedge-graded exposures, are tied together at the point of overlap. Curve segments were first smoothed by employing the linearized form of the logistic distribution function. This function allows calculation of gradient-exposure and gradient-density relations for the full characteristic curve.

Humans↗
PubMedDate not supplied

Transfer function measurement and analysis for a magnetic resonance imager.

The transfer function characteristics of a 1.5T imager have been determined. An edge response function (ERF) was obtained from a water/Plexiglas interface at various pixel widths ranging from 0.312 to 1.0 mm. An SE pulse sequence was used with a 5-mm transaxial slice. The ERF was smoothed, differentiated, and Fourier transformed to obtain MTF curves. The LSF was analyzed for skewness and kurtosis. The area under the MTF amplitude curves and the equivalent bandpass were calculated. All ERFs, LSFs, and MTFs were well behaved. The resulting LSF was Gaussian. All calculated MTFs had cutoff frequencies slightly less than the theoretical Nyquist limit. The MTF calculated from the theoretical Gaussian LSF is slightly superior to that calculated from experimental data and provides an upper limit to the MTF. Spatial resolution in our MR imager is dominated by the pixel size via the Nyquist sampling theorem. System performance is slightly less than theoretically predicted, possibly due to image processing algorithms during the reconstruction process.

Humans↗