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S Walker

Publications and source records attributed to S Walker.

At least 451 records · Page 25Linked to original sources
PubMedDate not supplied

Electron dose calculation using multiple-scattering theory: evaluation of a new model for inhomogeneities.

In this article, the fifth in a series on the calculation of electron dose using multiple-scattering theory, the predictions of a new model for dealing with localized inhomogeneities will be examined (Med. Phys. 18, 123-132, 1991). That model is in the form of a perturbation series, and for a thick half-slab configuration explicit formulas are worked out for the dose directly deposited by the primary electrons, for three reasonable cutoffs of the series. The predictions of this model with EGS4 Monte Carlo calculations for the half-slab configuration are compared, and they are found to be quite accurate in the region under the edge of the half-slab. On the other hand, the "Hogstrom algorithm," which is currently the most advanced method in routine clinical use, is found to give poor accuracy for this configuration.

Algorithms↗
PubMedDate not supplied

Installation of EGS4 Monte Carlo code on an 80386-based microcomputer.

This article presents the considerations and efforts involved to install and fully support the EGS4 radiation-transport Monte Carlo simulation code on an 80386-based microcomputer. It also presents some EGS4 benchmark timing comparisons between this and other computer architectures.

Electrons↗
PubMedDate not supplied

Use of Queensland Hospital services by interstate and overseas visitors.

In response to concerns about the number of interstate and overseas visitors using Queensland hospital services, the present study examined a sample of 1,295 hospital records to determine the proportion of patients who were incorrectly identified as Queensland residents. Across six hospitals the overall detection rate was 4.6%. Rates varied between hospitals, with the highest detection recorded for Goondiwindi near the Queensland/New South Wales border; and the lowest for Prince Charles in Brisbane. There were also important variations across hospitals based on specific holiday periods. In particular, Goondiwindi and the Gold Coast had substantially higher detection rates for the Christmas holiday period (December-January) than for the mid-year period (June-August). These findings are discussed in terms of their implications for hospital services, especially lost revenue and increased patient load. Health information managers are identified as a key group for addressing some of the current problems in this area.

Catchment Area, Health↗
PubMedDate not supplied

Comparing ICD-9-CM and ICD-10 classification systems in a primary health care setting: some initial observations.

The ICD-10 is due to be introduced into Australia during the late 1990s, superseding the current and widely used ICD-9-CM. Improvements in areas such as number of codes, an expanded external cause framework, and more context to injuries are expected to make the ICD-10 a more streamlined system for practitioners. The present study examined both classification formats using data from 1183 presentations to primary health clinics at island tourist resorts. Some initial observations are made about differences in the two systems, highlighting the greater coding detail provided by the ICD-10, particularly in the area of injuries. It is recommended that further empirical testing be undertaken using the ICD-10 in a variety of settings so as to identify benefits in the coding of both medical conditions and injuries.

Abstracting and Indexing↗
PubMedDate not supplied

The hemodynamic effects of intravenous labetalol for postoperative hypertension.

Hemodynamic data were analyzed from 25 courses of intravenous pulse labetalol therapy for postoperative hypertension in 12 patients after major vascular surgeries. The hemodynamic determinations were obtained an average of 15 minutes after a therapeutic total dose of 10-120 mg of labetalol (mean, 37.5 mg). The mean arterial pressure (MAP) decreased an average of 27 mmHg or 20% after intravenous labetalol. This normalization of the postoperative hypertension was associated with a 19% increase in cardiac output (CO) and cardiac index (CI) (CO mean increase of 0.58 L/min and CI increase of 0.31 L/min/m2). Commensurate with this decrease in MAP and increase in CO was an average decrease in systemic vascular resistance (SVR) of 625 dyne/sec/cm-5 or 25%. The pulmonary vascular resistance decreased 15 dyne/sec/cm-5 or 4%. The heart rate decreased 9 beats per minute or 10% and the left ventricular stroke work improved by 9% or 1.6 g/m2/beat while the right ventricular stroke work increased by 33% or 2.8 g/m2/beat. The hemodynamic responses to intravenous labetalol in these patients were all beneficial, and there were no adverse effects secondary to the pulse doses of labetalol. Labetalol appears to be safe and efficacious for the treatment of postoperative hypertension in patients undergoing major vascular surgery.

Aged↗
PubMedDate not supplied

Orthopaedic patients' reporting of pain management.

Advances in pain management have occurred in recent years through the development of patient-controlled and epidural analgesia, while the conventional regime of intramuscular analgesia has also continued to be used. This article describes a study comparing orthopaedic patients' experiences of postoperative pain using the three methods of analgesia.

Analgesia, Epidural↗
PubMedDate not supplied

A positive approach.

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

Family therapy: concepts, models and applications.

Family therapy is a relatively new form of treatment in child and adolescent psychiatry. It developed from a clinical tradition of treating individuals into a model which actively addressed the family and wider context of symptom presentation. This article sets out some of the concepts underpinning this treatment. It reviews the three major models practised in the UK. It includes contemporary developments and critiques based on anti-oppressive and antidiscriminatory theory.

Adolescent↗