Inherent limitations in ectomography

Ectomography, a general tomographic method currently being implemented in nuclear medicine, is described. The object is viewed from different directions from the same projection angle, and the reconstruction process can be described as a two-dimensional filtered back-projection technique. One limitation of this limited-angle approach is that a three-dimensional Fourier representation of the acquired projections has a cone where data are missing. This empty cone can cause distortions in the tomogram by insufficient elimination of details outside the reconstructed tomographic section and by distortion of details in the section. The degree of distortion is dependent on the extension of the object in all directions and on the projection angle. Despite these limitations ectomography can be superior to single-photon-emission computed tomography for imaging sections that are close and parallel to the surface of the object, as in imaging of the hip joint or the heart.     

Standing up to the big squeeze

Consumer confidence is at its lowest ebb since 1980. Economic growth is at a standstill & unemployment & inflation are both rising. Here's a front-line report from more than three dozen operators who are fending off the recession's dual pressures of slow sales & rising costs. They are using discount pricing, partnering with vendors, setting pay for performance standards & a variety of other recession-beating practices.     

A multistep iterative proportional fitting procedure to estimate cohortwise interregional migration tables where only inconsistent marginals are known

Some problems concerning the application of the interregional cohort survival model developed by Andrei Rogers to the analysis of regional population dynamics are first discussed. The author then develops an iterative proportional fitting procedure in order to estimate a complete migration table where only inconsistent marginals are available. The procedure is applied to 1988 data for Kanagawa prefecture in Japan.     

The effect of appraisers in estimating metabolic rate with the Edholm scale

A study was made of the appraisers' effect on the estimation of metabolic rate with the Edholm scale and a table of the ISO 7243 heat stress standard. The appraisers, five experienced and five inexperienced persons, estimated the metabolic rate of three different work tasks from videotapes. Analysis of variance indicated significant ( [Formula: see text] ) differences in the appraisers' recordings of the activities. The appraisers were grouped according to the similarity of the estimated values they gave. The groups thus contained both experienced and inexperienced appraisers, and it was not possible to classify the appraisers into experienced and inexperienced groups according to their earlier experience. The metabolic rates according to the Edholm scale were higher than according to the ISO 7243 table. The differences in metabolic rates given by the individual observers varied from 38 to 118 W/m(2). The variations in the estimation of metabolic rates were greater when the Edholm scale was used. This variation caused considerable variation also in the predicted mean vote, PMV index. It is recommended that the appraisers be selected carefully, because it is not possible to know whether a randomly selected appraiser is an 'average' or an 'extreme' appraiser without a test. Before conducting extensive field surveys where several appraisers estimate the metabolic rates, it would be useful to arrange training in order to calibrate the levels of the Edholm scale as well as ISO method among the appraisers because training clearly unified the estimation.     

A strident public impatience drives true change. Interview by Carolyn Dunbar

Sunquest's president and chief executive officer, Sidney Goldblatt, M.D., says the inefficient way information is shared in healthcare is "stupid" and wouldn't be tolerated in other industries. Until the public becomes impatient and strident about flagrant waste and begins to demand most cost-effective methods in healthcare, true change will take a lot longer.     

A new era dawns for the University Hospital Consortium. Interview by Carolyn Dunbar

A group of 60 university hospitals and medical centers has evolved from its original goal of gaining greater purchasing clout to a new goal: The University Hospital Consortium is becoming an information corporation, with the enormous information potential to affect treatment outcomes, practice patterns and clinical research. Sam Schultz, UHC's vice president of Information Services, tells Computers in Healthcare his organization is on the verge of a new age of discovery.     

Apple founder targets healthcare as NeXT market. Interview by Carolyn Dunbar and Michael L. Laughlin

Cofounder and former chairman of the board of Apple Computer Steven Jobs looks beyond the 1980s image of a petulant, embittered young man, fighting with all who failed to share his vision, and many who did. Today, as a founder, president and chairman of NeXT, Inc., he looks to more high-minded applications of his computer genius.