Faculty Bibliography

We have investigated the use of a simple expert system to generate a PACS configuration from a simple set of specifications. This paper will describe the initial expert system and its rules and the simulation display tool. While there have been several other projects which have simulated PACS systems, none have tried to automatically generate system configurations

We describe a software system developed to handle images obtained from different sources, namely, computer-assisted tomography, positron emission tomography, single photon emission tomography and magnetic resonance imaging. In developing the system, it was necessary to address the following points. (1) The types of values that were encountered in both the header information and the pixel elements, namely, integers, floating point numbers, complex numbers and strings. (2) The use of domain-dependent sets of keys, that is, how to choose keys and how to stabilize the use of keys among the user population. This is, for example, how information such as the patient name, or the activity in becquerel is kept. It is necessary to keep both the key values and the units. (3) The development of a method for providing a database using flat files, i.e. linear text. (4) The maintenance of a history of values and operations. This is necessary in order to address the problem of determining from an image how that image was produced. The connection between an image and how it was derived is analogous to describing how a secondary standard is derived from a primary one

The intent of this paper is to understand the characteristics of those frame buffers currently used to display images, versus more ideal frame buffers for medical image display purposes. This study is based on current needs and what characteristics might be desirable. Two case examples are presented: (1) a system developed for high quality computer graphics and (2) a system developed for nuclear medicine and radiation therapy treatment planning. Our study considers: (1) defining a pixel depth sufficient to hold data, (2) the desirability of multiple color look-up tables, (3) how cine loops are managed, and (4) display memory size

Anatomic localization in functional (such as PET) imaging often requires a structural (such as CT or NMRI) study of the brain in the same plane. Some neuropsychiatric conditions make it difficult for a patient to hold his/her head immobile even when a rigid head holder is used. We studied the effect of tilt of the anatomic reference image, in this instance CT, relative to the functional image, here PET, on the quantification of receptor ligand concentration in anatomically defined regions of the brain

Two major difficulties associated with medical image processing are the diverse image formats that must be dealt with because of the differences in image sources and the number of incompatible display systems available for viewing images both before and after processing. We describe a very small set of primitives that need to be defined to utilize any raster display. When these primitives have been implemented for a particular device, then a standard set of image display programs can be compiled and images and the results of image processing can be displayed. The main purpose of this paper is to describe what a raster display looks like from the point of view of the programmer and to define the specific hardware and software data about the raster display that must be known in order to implement the small set of primitives

There is great interest at present in incorporating image-management systems popularly referred to as picture archiving and communication systems (PACS) into imaging departments. This paper will describe various aspects of local area networks (LANs) for medical images and will give a definition of terms and classification of devices by describing a possible system which links various digital image sources through a high-speed data link and a common image format, allows for viewing and processing of all images produced within the complex, and eliminates the transport of films. The status of standards governing LAN and particularly PACS systems along with a proposed image exchange format will be given. Prototype systems, particularly a system for nuclear medicine images, will be presented, as well as the prospects for the immediate future in terms of installations started and commercial products available. A survey of the many questions that arise in the development of a PACS for medical images and also a survey of the presently suggested/adopted answers will be given