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Biomedical subjects

S Einstein

Publications and source records attributed to S Einstein.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of tumor measurements in oncology: use of film-based and electronic techniques.

PURPOSE: To evaluate the variability in bidimensional computed tomography (CT) measurements obtained of actual tumors and of tumor phantoms by use of three measurement techniques: hand-held calipers on film, electronic calipers on a workstation, and an autocontour technique on a workstation. MATERIALS AND METHODS: Three radiologists measured 45 actual tumors (in the lung, liver, and lymph nodes) on CT images, using each of the three techniques. Bidimensional measurements were recorded, and their cross-products calculated. The coefficient of variation was calculated to assess interobserver variability. CT images of 48 phantoms were measured by three radiologists with each of the techniques. In addition to the coefficient of variation, the differences between the cross-product measurements of tumor phantoms themselves and the measurements obtained with each of the techniques were calculated. RESULTS: The differences between the coefficients of variation were statistically significantly different for the autocontour technique, compared with the other techniques, both for actual tumors and for tumor phantoms. There was no statistically significant difference in the coefficient of variation between measurements obtained with hand-held calipers and electronic calipers. The cross-products for tumor phantoms were 12% less than the actual cross-product when calipers on film were used, 11% less using electronic calipers, and 1% greater using the autocontour technique. CONCLUSION: Tumor size is obtained more accurately and consistently between readers using an automated autocontour technique than between those using hand-held or electronic calipers. This finding has substantial implications for monitoring tumor therapy in an individual patient, as well as for evaluating the effectiveness of new therapies under development.

Humans↗
PubMed1994

Substance use intervention failure: a point of view or how the cure becomes the disease or an ode to experts on incurability or masking the disease, mitigating someone's pain but providing no basic cure/solution.

Substance use intervention, both in the private and public sectors, continues to be associated with failure. This paper makes the assumption that: 1) there is a need to systematically consider and explore FAILURE in its various parameters (definitions, characteristics, forms, shapes, potencies, densities, directions, tempos, levels, phases, meanings, and adhesiveness), sources, and "demands" in the broad area of substance use intervention; 2) we can learn from failure (categorizing its processes and outcomes, selecting foci for intervention, and failure's "veracity," status, transmittability and potential/actual usability over time); and 3) we should continue to repeat this process until there is little need to do so. As times and definitions change, there will never be an end to failure or the need to learn from failure. Failure is considered as a value, and having value, on a multidimensional, dynamic gradient (minimal to maximal), being describable, discernable, catagorizable, understandable, while being-culture-site-ideologically bound/influenced. Exploring FAILURE offers us-in our various substance use intervention roles-the opportunity to learn from what we have done and to more appropiately plan, implement, and assess what we may want and/or need to know and to do. Examples are given of ongoing sources of built-in substance use intervention failure.

Follow-Up Studies↗
PubMed1993

[Fast spin echo MRI techniques. Contrast characteristics and clinical potentials].

Based on partial RF echo planar principles, Fast Spin Echo techniques (FSE) were implemented on high field systems. These methods produce image quality and contrast which resemble to conventional spin echo (SE) techniques. By reducing acquisition times by factors between 1.4 and 16 over SE methods, FSE allows for several imaging options usually prohibitive with conventional spin echo (SE) sequences. These include fast scans (especially breath-hold acquisitions); improved T2 contrast with longer TR intervals; increased spatial resolution with the use of larger image matrices and/or smaller fields of view; and 3D volume imaging with a 3D multislab FSE technique. Contrast features of FSE techniques are directly comparable to those of multiple echo SE sequences using the same echo spacing than FSE methods. However, essential contrast differences existing between the FSE sequences and their routine asymmetric dual SE counterpart can be identified. Decreased magnetic susceptibility effects and increased fat signal present within T2 weighted images compared to conventional dual SE images are due to the use of shorter echo spacings employed in FSE sequences. Off-resonance irradiation inherent to the use of a large number of radio frequency pulses in shown to results in dramatic magnetization contrast transfer effects in FSE images acquired in a multislice mode.

Abdomen↗
PubMed1992

First principles of fast spin echo.

Fast spin echo (FSE), a variant of the rapid acquisition with refocused echoes pulse sequence, is now being widely considered as an alternative to conventional spin echo for proton density and T2-weighted imaging. Although the medical experience with this sequence is relatively limited, relevant aspects of the technique have been well understood in the context of spectroscopic applications for many years. This article attempts to portray the subject in an appropriate historical context. Such a viewpoint promotes a deeper understanding of the artifacts, determinants of contrast, and future evolution of FSE. Hopefully, this may not only be of benefit in the design of optimal clinical imaging protocols for current state of the art but may also be of use in fashioning the criteria by which new developments in this field may be judged.

Artifacts↗
PubMed1986

Treating the drug user: considering the "demands" of therapeutic technologies and their implications for treatment planning, implementation, and outcome.

Continued confusion regarding the actual and potential interface between technical issues (techniques/therapies) and ideological-theoretical considerations (treatment as a planned change process) results in built-in failure in the treatment of drug users. Only a limited number of currently available "therapies" are generally used for planned treatment intervention or for institutionalized reflexive reactions. Limited consideration has been given to the planning and implementation "demands" of a selected number of critical variables which affect the "therapies" currently in use and/or which can be chosen to be used. This note is designed as a catalytic cognitive resource to facilitate changing this situation by exploring some of the factors associated with this self-defeating, self-fulfilling prophecy.

Humans↗