Considerations On An Algorithm For Activation Of Images In A Multi-Layered Storage System Within A PACS

Abstract

One of the major bottlenecks in realizing a full size PACS is the image storage component. Further technological developments are necessary before sufficient capacity can be realized. It can be expected that a multi-layered storage structure will be necessary where large capacity with relatively long access times will be offered at the lowest level. The higher levels will show decreasing access times combined with decreasing capacity. Both in the judgement of images acquired in the diagnostic study and in the work of the clinician historical images of the patient concerned may be needed. If these images had to be retrieved from the lowest storage level at the moment they are needed, the service time would definitely be unacceptable. So a strategy is necessary for the anticipation of the need of access to images. In this paper a first attempt is made to identify relevant parameters to be used in such a look ahead algorithm for the activation of images to a next level. A simple algorithm is suggested; the need for further study is emphasized.