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Methods have been developed for on-line computer enhancement of a scintillation camera's myocardial images and for a graphical presentation showing relative thallium-201 activity in the myocardium. Enhancement uses fast Fourier transform techniques. The methods have been applied to multiple images obtained after stress and 4--5 hr rest. Patients with(More)
  • E L Yeh
  • 1977
Different types of reverberations which may cause confusing artifacts in echocardiograms are described. Reverations between the targets may result in identifiable complex echo patterns. An echocardiogram with reverberating echoes is presented. Several experimental studies were done to explain the reverbating echoes. The reverberating echoes may be more(More)
This paper investigates the spectral properties of a one-dimensional photonic crystal (PC) containing an inhomogeneous polymer- dispersed liquid crystal (PDLC) as a defect layer. Experimental results indicate that the voltage-induced reorientation of LC molecules between the light-scattering and transparent states in the PDLC enables the electrical tuning(More)
  • E L Yeh
  • 1984
Although 67Ga imaging has been widely used in the diagnosis of malignant and inflammatory diseases, its uptake in the stomach has been reported in the literature mainly in gastric lymphoma and carcinoma. As shown by this report, intense gastric uptake of the radionuclide may be seen not only in malignancy, but also in gastritis, and even in the stomach(More)
Proper orientation of the B-mode ultrasonic aspiration transducer is important for accurate imaging during aspiration biopsy. The transducer extension axis must be perpendicular to the plane of the scanning arm for accurate representation of reflector locations. Single pass scans without compound angulation of the transducer are recommended when(More)
  • E L Yeh
  • 1979
Distortion of the bar-phantom scintiphoto using the medium-energy collimator may lead to the misconception that the resolution of the medium-energy collimator is better than that of the low-energy collimator. The distortion is illustrated by superposition of the transparent films of the bar-phantoms and collimator.