DR and CR: Recent advances in technology.

After some initial reluctance, nowadays transition from conventional analogue-to-digital radiographic technique is realized in the vast majority of institutions. The eventual triumph of digital over conventional technique is related to its undoubted advantages with respect to image quality and improved image handling in the context of a picture archiving and communication system. CR represents the older system, which matured over decades and experienced some important recent improvements with respect to dose efficiency and work-flow efficiency that strengthened its position. It represents a very versatile, economically attractive system that is equally suited for integrated systems as well as for cassette-based imaging at the bedside. DR systems offer superb image quality and realistic options for dose reduction based on their high dose efficiency. While for a long time only integrated systems were on the market suited for a large patient throughput, also mobile DR systems became recently available. While for the next years, it is likely that DR and CR systems will coexist, the long term perspective of CR will depend on further innovations with respect to dose efficiency and signal-to-noise characteristics while for DR economical aspects and broader availability of mobile systems will play a role.

Flat detectors and their clinical applications.

Diagnostic and interventional flat detector X-ray systems are penetrating the market in all application segments. First introduced in radiography and mammography, they have conquered cardiac and general angiography and are getting increasing attention in fluoroscopy. Two flat detector technologies prevail. The dominating method is based on an indirect X-ray conversion process, using cesium iodide scintillators. It offers considerable advantages in radiography, angiography and fluoroscopy. The other method employs a direct converter such as selenium which is particularly suitable for mammography. Both flat detector technologies are based on amorphous silicon active pixel matrices. Flat detectors facilitate the clinical workflow in radiographic rooms, foster improved image quality and provide the potential to reduce dose. This added value is based on their large dynamic range, their high sensitivity to X-rays and the instant availability of the image. Advanced image processing is instrumental in these improvements and expand the range of conventional diagnostic methods. In angiography and fluoroscopy the transition from image intensifiers to flat detectors is facilitated by ample advantages they offer, such as distortion-free images, excellent coarse contrast, large dynamic range and high X-ray sensitivity. These characteristics and their compatibility with strong magnetic fields are the basis for improved diagnostic methods and innovative interventional applications.

Financing a large-scale picture archival and communication system.

RATIONALE AND OBJECTIVES: An attempt to finance a large-scale multi-hospital picture archival and communication system (PACS) solely based on cost savings from current film operations is reported. MATERIALS AND METHODS: A modified Request for Proposal described the technical requirements, PACS architecture, and performance targets. The Request for Proposal was complemented by a set of desired financial goals-the main one being the ability to use film savings to pay for the implementation and operation of the PACS. RESULTS: Financing of the enterprise-wide PACS was completed through an operating lease agreement including all PACS equipment, implementation, service, and support for an 8-year term, much like a complete outsourcing. Equipment refreshes, both hardware and software, are included. Our agreement also linked the management of the digital imaging operation (PACS) and the traditional film printing, shifting the operational risks of continued printing and costs related to implementation delays to the PACS vendor. An additional optimization step provided the elimination of the negative film budget variances in the beginning of the project when PACS costs tend to be higher than film and film-related expenses. CONCLUSION: An enterprise-wide PACS has been adopted to achieve clinical workflow improvements and cost savings. PACS financing was solely based on film savings, which included the entire digital solution (PACS) and any residual film printing. These goals were achieved with simultaneous elimination of any over-budget scenarios providing a non-negative cash flow in each year of an 8-year term.

[Digital radiography: from storage phosphor plates to direct detector systems]. / Digitale Radiographie: Von der Speicherfolie zum Direktdetektor.

All three currently commercially available systems for digital radiography of the chest such as the selenium drum, storage phosphor plates and the flat panel direct detector systems provide an excellent image quality that is at least equivalent or superior to that of conventional film. Reasons for that are the continuously improved detective or dose efficiency of the detector systems and an improved image processing. The new direct detector systems have the largest potential for dose reduction while storage phosphor and selenium radiographs are usually obtained with a dose comparable to that of a 400 speed system. Improved image processing algorithms allow for the production of digital images that are adapted to the conventional image characteristics within the lung regions combined with an increased transparency of the high absorption areas such as the retrocardial and retrodiaphragmatic regions.

[Development and current status of invasive coronary angiography]. / Entwicklung und aktueller Stand der invasiven Koronarangiographie.

Invasive selective coronary angiography as a clinical method is about 40 years old. This article surveying this period, written by an R&D engineer, deals with four parts: first the situation before 1965 is touched upon. For the time after 1965 the second and third parts describe the development of the procedure and of the technique with special reference to the work of Prof. Dr. K. Bachmann and to the facility, which in 1967 was designed together with him and further developed. K. Bachmann had already taken up the method of invasive coronary angiography around 1965, which makes him one of the group of pioneering users who developed the fundamentals of the procedure and led coronary angiography to its self-evident use today. The first clinical application of high resolution image intensifier with the input screen produced from evaporated cesium iodide in 1971 appears as one of the highlights of the continuous improvements of the facility. The fourth part of the article sketches the status of today and, considering the new methods using MRI, EBCT as well as CT, it predicts that the invasive coronary angiography will remain an indispensable method at least for the medium-term future.

Actualización en el uso del sistemas pantalla-película en radiología convencional / Update in screen-film systems use in conventional radiology

En la mayoría de los Servicios y Centros Radiológicos de nuestro país se utilizan los sistemas detectores de pantalla-película de fósforos de tierras raras con emisión de luz verde y película sencible a la misma; sin embargo, en algunos Centros del Sistema Público de Salud aún se utilizan pantalla película convencionales de tungstato de calcio, que emite luz azul, con película sencible a este color (por ej: en el Hospital San Juan de Dios, Peumo, Quillota, Puerto Natales, San José de Maipo). El objetivo del presente artículo es proporcionar a los profesionales herramientas que les permitan optimizar el empleo de los sistemas detectores, que son elementos accesorios de gran importancia de la abtención de imágenes radiográficas de alta calidad diagnóstica, logrando además disminuir la dosis de irradiación al paciente y una mayor duración del tubo de rayos X, entre otras características

[Medical x-ray equipment on the threshold of the 21st century]. / Meditsinskaia rentgenotekhnika na poroge XXI veka.

The authors, specialists in medical X-ray engineering, have been engaged in it for about 40 years, forecast that this medical engineering field will be under development and regard its development as transition to a qualitative new level prepared by latest technologies in X-ray apparatus making, digital television, and computed technology rather than an ultimate landmark of evolution.

New and future developments in screen-film mammography equipment and techniques.

Two improvements in mammography equipment during the last 4 years will greatly affect the practice of mammography during the next decade: dose reduction and improved testing equipment for monitoring the quality of mammography. The increased use of digital radiography has stimulated studies comparing digital mammography with screen-film mammography. Some digital algorithms for detecting clusters of calcifications may have application in screening mammography within the next decade.