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Biomedical subjects

W R Hendee

Publications and source records attributed to W R Hendee.

At least 109 records · Page 6Linked to original sources
PubMed1983

The impact of future technology on oncologic diagnosis: oncologic imaging and diagnosis.

Over the past few years, the discipline of medical imaging has entered an evolutionary period that reflects primarily the introduction of computers and digital technology into the imaging process. Clinical applications of this evolution realized to date (e.g., transmission computed tomography, ultrasound and quantitative nuclear medicine) are only indicative of future developments that promise to increase the contributions of medical imaging in a very substantial manner. This increase in the area of oncologic diagnosis is one of the more exciting possibilities existing in medicine today.

Antibodies, Monoclonal↗
PubMed1983

In vivo diagnostic nuclear medicine. Pediatric experience.

The use of radiopharmaceuticals for diagnostic tests in children is increasing and interest in these is evidenced by the addition of scientific sessions devoted to pediatric medicine at annual meetings of The Society of Nuclear Medicine and by the increase in the literature on pediatric dosimetry. Data presented in this paper describe the actual pediatric nuclear medicine experience from 26 nationally representative U.S. hospitals and provide an overview of the pediatric procedures being performed the types of radiopharmaceuticals being used, and the activity levels being administered.

Adolescent↗
PubMed1983

Noise reduction in nuclear medicine images.

Common methods of reducing random noise in nuclear medicine use lowpass filtering, which has the disadvantage that it affects high-frequency components of the image. We developed a noise-reduction approach that estimates signal and noise levels in each of several frequency bands and removes the appropriate amount of noise with little effect on the signal in each band.

Radiographic Image Enhancement↗
PubMed1983

Real and perceived risks of medical radiation exposure.

There is almost no subject that elicits greater concern and less objective understanding than that of exposure of patients to radiation accompanying diagnostic radiologic procedures. One or more of the health effects (cancer, developmental abnormalties and genetic changes) attributed to low-level exposure to radiation are frequently misinterpreted as likely consequences rather than statistical risks following radiation exposure. Even less well understood is the small magnitude of the risks accompanying radiation exposure compared with those related to activities encountered during the daily routine. For this reason, the perception of risk associated with exposure to low-level radiation is inconsistent with the reality of the risk as estimated by even the most conservative models of radiation injury.

Abnormalities, Radiation-Induced↗
PubMed1982

Reduction of radiation exposure in radiography of the chest.

Reduction of patient exposure in chest radiography by means of copper filtration was investigated for a range of filter thicknesses at kilovoltages commonly employed for the postero-anterior and lateral projections. The influence of copper filtration on tube output, beam quality, entrance and midplane exposures, tube load, and image contrast was determined from physical measurements and evaluation of phantom images. The results indicate that entrance exposure may be reduced by 30-40% and midplane exposure by approximately 24% through the use of a 0.32-mm copper filter, with an acceptable increase in tube load and only minor changes in the appearance of the images.

Copper↗
PubMed1982

Problems with contrast-detail curves for CT performance evaluation.

Contrast-detail curves have been used frequently to describe the low contrast performance characteristics of computed tomography (CT) scanners. However, such curves can produce misleading conclusions if the effects of all variables influencing CT images are not considered. As shown in this experimental study, improperly designed contrast-detail curves disguise differences in CT performance when the same object is imaged with different x-ray spectra. These problems arise because contrast is defined as the difference in system-dependent CT numbers rather than the actual difference in the object. An alternate approach to CT performance evaluation using "difference-detail" curves is offered.

Humans↗
PubMed1981

Carbon-fiber materials in radiology.

While cassettes, table tops, and film changers made of carbon fiber have been recommended by many authors, there is controversy as to whether the advantages of the new materials outweigh the marked increase in cost. Carbon-fiber materials transmit more lower-energy radiations; thus a lower mAs can be used, which in turn permits a reduction of 15-30% in exposure time. However, x-ray transmission under actual clinical conditions has not been as good as originally hoped.

Carbon↗
PubMed1981

X-ray equipment performance: a 3.5 year case history.

The continuing performance of radiographic imaging systems has become increasingly important as the complexity and cost of these systems continue to escalate, as replacement funding becomes more difficult to obtain, and as advisory and regulatory agencies place increasing emphasis on equipment-oriented quality control procedures. As a guide to the continuing performance of these imaging systems, selected performance indicators for two general-purpose radiographic-fluoroscopic units have been monitored for a 3.5 year period. The observations suggest that with inspection and adjustment at 6 month intervals for generator, x-ray tube, and beam restriction systems, and at 2 month intervals for the intensified fluoroscopic imaging system, the overall performance of the imaging systems can be maintained at a high level of consistency equivalent to the performance achieved when the equipment was initially installed.

Fluoroscopy↗
PubMed1981

Quality control of scintillation cameras using a minicomputer.

A minicomputer-based technique compiles objective indicators of scintigraphic system performance. The evaluation begins with the acquisition of a single image of an orthogonal hole pattern from which quantitative and regional measurements of point-source sensitivity, spatial resolution, and spatial linearity are derived. Two computer programs offer the user different but complementary features. The first program is the basis of an evaluation performed by a technologist for purposes of quality control. Operator intervention is minimal, and the entire protocol, including data acquisition and processing, can be completed in 20 min. The results are automatically compiled and displayed as graphs showing 100 consecutive sets of daily performance measurements. A second computer program is designed as an interactive diagnostic and research tool to display measurements as histograms and functional images. The operator can use the program to determine the quantitative and spatial characteristics of the system's intrinsic performance measurements made during the quality-control evaluations.

Computers↗