Developments in digital radiography: an equipment update

Digital X-ray imaging technology has advanced rapidly over the past few years. This review, particularly aimed at those involved in using and purchasing such technology, is an attempt to unravel some of the complexities of this potentially confusing subject. The main groups of X-ray imaging devices that are considered are digitisers of conventional radiographs, image-intensifier-based fluorography systems, photostimulable phosphor computed radiography, amorphous selenium-based technology for thorax imaging and flat-panel systems. As well as describing these different systems, we look at ways of objectively assessing their image quality. Concepts that are used and explained include spatial resolution, grey-scale bit resolution, signal-to-noise ratio and detective quantum efficiency. An understanding of these basic parameters is vital in making a scientific assessment of a system's performance. Image processing and techniques are also briefly discussed, particularly with reference to their potential effects on image quality. This review aims to provide a basic understanding of digital X-ray imaging technology and enables the reader to make an independent and educated assessment of the relative merits of each system.

Neurologic recovery and neurologic decline after spinal cord injury

Physicians caring for patients with spinal cord injury facilitate neurologic recovery by optimizing nutrition and general health, by coordinating active exercise and functional training to enhance the underlying synapse growth, reversal of muscle atrophy, and motor learning, and by controlling interfering spasticity. SCI physicians also must monitor for neurologic decline during initial rehabilitation and later in life, diagnose promptly and accurately such decline, and orchestrate the appropriate intervention.

Substance abuse and sexual activity in an overseas population of adolescent military dependents

To determine the incidence of high-risk behaviors, such as substance abuse and sexual activity, in an overseas population of adolescents, and how these rates compared to the general population in the United States, a survey of high school-aged military dependents residing overseas was undertaken. A questionnaire was designed and distributed to all 8th through 12th graders at the Department of Defense Dependent's School in Seoul, Korea. Use of tobacco products and a history of illicit drug use was similar to that of referant groups in the United States. Present use of illicit drugs was decreased. Use of alcohol was increased over that of similar age groups in America. The authors discuss these findings in light of the environmental differences in the overseas military community.

Oral administration of active vitamin D metabolites to low birthweight infants

The active vitamin D metabolites 1 alpha, 25-dihydroxycholecalciferol (Rocaltrol) and the analogue 1 alpha-hydroxycholecalciferol (One-Alpha) are adequately absorbed after oral administration in the preterm infant. The absorption pattern is similar to that seen in adults.

A model for dental workload measurement

The primary purpose of the study was to develop a model that would provide an efficient and standardized approach to workload reporting in a non-fee (HMO-like) dental care system. The model was also designed to predict the dental personnel resource requirements in the system as the overall dental needs of the population were already known. To accomplish this, a set of 246 task/procedures representing the broad scope of dental practice was developed. For each task/procedure, a Best Time-weighted Estimate (BTE) in terms of average expected man-minutes of work required for accomplishment was developed from over 35,000 actual time measurements on patient visits to 29 US Army dental clinics located throughout the United States. Because of the nature of the specific task/procedure data, it was necessary to use four different mathematical models to produce statistically optimal BTEs. It was concluded that, cumulatively the BTEs developed for each task/procedure evaluated could be used as a basis for both the development of a Dental Care Composite Unit workload measure and the determination of overall dental personnel resource requirements in a non-free dental care system.

Etiology of viral hepatitis in American soldiers

To define better which types of hepatitis are prevalent among American soldiers, the authors studied 413 separate episodes of acute viral hepatitis among 412 soldiers admitted to US Army hospitals during 1978-1979. Most soldiers (68.8%) had acute hepatitis B (estimated annual hospitalization rate: 5.41/1000 soldiers in West Germany, 2.51/1000 in South Korea, less than 1/1000 in the United States). Subtype ayw was predominant in Germany, whereas adr was predominant in South Korea. Hepatitis B was more often associated with contact history or parenteral use of drugs in West Germany than in South Korea (p less than 0.001). Non-A, non-B hepatitis accounted for 27% of cases in West Germany (2.16/1000), but only 3% in South Korea (0.11/1000); hepatitis A only 15% in South Korea (0.48/1000) and 1% in West Germany (0.08/1000). These findings indicate that hepatitis B is the most prevalent form of viral hepatitis among US soldiers worldwide but also suggest substantial differences in the epidemiology of this infection in South Korea and West Germany. Such data will be useful in developing hepatitis B immunization policy within the military.

The transmission and interpretation of emergency department radiographs

Twenty-five radiographic studies representative of the spectrum of trauma cases that might present to an emergency department were selected from actual cases presenting at Brooke Army Medical Center (BAMC) in San Antonio, Texas. The studies were then transmitted from a local television studio via satellite back to BAMC and three other Army hospitals. A panel of 29 physicians (11 radiologists, 7 emergency physicians, and 11 others from various specialty areas) viewed the images on commercial grade television sets and attempted to make a diagnosis. The diagnostic accuracy of the radiologists (86%) was significantly better than that of the other two groups (77% each). However, given the overall expense of a teleradiology network, this difference in accuracy - especially when translated into clinically significant errors - might not justify the establishment of such a network in terms of cost-effectiveness.

Serological markers for hepatitis types A and B among U.S. Arym soldiers, Germany

Viral hepatitis rates among U.S. Army soldiers in Europe have been found to be two to three times higher than corresponding rates for soldiers stationed in the U.S. Sera from 89 per cent of a representative Army unit with 865 members and a known hepatitis problem were tested for HBsAg, anti-HBs, anti-HBc, and anti-HA. The prevalence of HB markers was 20 per cent, and hepatitis A antibody was present in 25 per cent. A six-month follow-up, conducted on 260 individuals initially negative for all four tests, revealed that 11 of these were now HB seropositive, whereas none had seroconverted to anti-HA positive. The HB virus was the principal agent responsible for hepatitis in the unit surveyed.