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Biomedical subjects

B A Goddard

Publications and source records attributed to B A Goddard.

7 recordsLinked to original sources

Dynamic spatial resolution.

The study of the dynamic behaviour of radiopharmaceuticals within a patient using a scintillation camera with data acquisition and processing facilities often presents analytical problems because of the limited data available. In the effort to maintain good spatial resolution sensitivity is often needlessly reduced producing further limitation in the statistical accuracy within regions of interest. It is shown that for a particular dynamic study and scintillation camera combination an optimum design of collimator exists, often of much greater sensitivity and poorer resolution than those used hitherto. A simple method is given for producing data for any system which will provide the basic information necessary to read off optimal collimator design parameters.

Mathematics

A simple method for correcting left ventricular equilibrium radionuclide angiography for the effects of arrhythmias.

A simple method of correcting equilibrium radionuclide angiographic data for the effects of arrhythmias is proposed. This involves no further acquisition time or inconvenience to the patient. This correction is necessary in patients with marked arrhythmias as the left ventricular time-activity curve (LVTAC) becomes distorted with greater sampling time in the first few frames of the LVTAC than in later frames. This will show on the LVTAC as greater counts in the first few frames and will lead to an overestimation of left ventricular ejection fraction (LVEF) and wall motion. The method proposed normalises each frame to make the contribution from a non-cardiac region constant over the cardiac cycle. Results of the correction are presented and discussed.

Arrhythmias, Cardiac

Deconvolution analysis of the scintillation camera renogram.

A scintillation camera with digital data store has been used to assess renal function. Analysis of the renogram by deconvolution, using an on-line digital computer, shows promise as a means of expressing renal function in terms of tubular transit times for 123I-Hippuran.

Computers

Xenon-133, 127Xe, and 125Xe for lung function investigations: a dosimetric comparison.

Of the possible radionuclides of xenon, 127Xe and 125 Xe have better physical properties for lung function measurement than 133Xe. A comparison of the radiation doses for these three radionuclides has been made for a typical scintillation camera investigation. Using an exponential model for washin and washout of gas, it is shown that the specific activity-time relationship is always equal to the product of the spirometer concentration and the rebreathing period. It is concluded that of the three radionuclides 127Xe gives the lowest radiation dose during a typical lung function study.

Adipose Tissue