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Biomedical subjects

W Mauderli

Publications and source records attributed to W Mauderli.

6 recordsLinked to original sources
PubMed1979

A computerized rotating laminar radionuclide camera.

We have constructed a radionuclide camera that embodies a unique detector-collimator concept and provides a radically new approach to imaging. The heart of the instrument is a linear array of semiconductor detectors separated by thin tungsten plates that confine the field of view of each detector to one dimension. This collimator design has a higher collection efficiency than the standard parallel-hole collimator but cannot directly produce a two-dimensional image. When multiple measurements are taken as the array rotates through 180 degrees, a computerized image restoration algorithm can then produce two-dimensional images with resolution determined by the width of the detectors. A small prototype camera has produced images with resolution superior to conventional Anger cameras.

Computers↗
PubMed1975

Analysis of errors in three-dimensional reconstruction of radium implants from stereo radiographs.

The present method of steroe shift for three-dimensional (3-D) reconstruction of radium implants has been found to produce displacement errors. Analysis shows that the maximum displacement error decreases as the shift (S) increases with fixed focal spot-film distance (H), while conversely for a fixed shift distance the maximum displacement error with increased focal spot-film distance. The authors suggest that sufficiently accurate 3-D reconstruction may be achieved when H greater than or equal to 100 cm and H/S less than 2.

Computers↗
PubMedDate not supplied

Plastic scintillation filament detector system for 14CO2 breath-analysis tests.

A 14CO2-measuring system for breath-analysis tests is described which utilizes plastic-scintillator filaments as radiation-detector elements. The 14C radioactivity in expired breath is measured directly, thus eliminating the need for trapping and counting of liquid scintillation-counting solutions. Total CO2 concentration in expired breath is measured by an infrared detector, making no assumption of endogenous CO2 output and enabling results to be expressed as either a concentration (percentage of administered dose per unit of CO2) or total expired 14CO2. Advantages of this system over an ionization chamber are: significantly lower background variation and shorter breathing time to fill completely the detecting chamber with expired air. The system is easy to operate, transportable on a small cart to the patient's bed if necessary, and applicable for continuous monitoring of 14CO2 in experimental animal studies.

Breath Tests↗
PubMedDate not supplied

Rotating laminar emission camera with Ge-detector: further developments.

A germanium (Ge) camera with laminar collimator-detector geometry, ROLEC, simulating a 195 X 195 mm2 detection area, has been constructed and tested. The detector consists of five separate Ge blocks grooved into distinct electrical channels. Results show that ROLEC measuring times have to be about 3 X greater than Anger camera measuring times to achieve a 5% signal-to-noise ratio with each device. Both spatial and energy resolution of the ROLEC exceed that of the Anger camera but sensitivity variations along the detector strips pose a significant problem in development of a clinically useful device.

Animals↗