Prefetch Worklist

Prefetching downloads selected studies from the eRAD PACS server to the local workstation. As a result, opening a study loads the data from the local workstation rather than from across the network, greatly improving the load time.   

The data staged to the workstation is based on two user-defined worklists:

• Prefetch - Download the entire study
• Prefetch thumbnails - Download the study’s meta-data only   

When logging into a server from a workstation, eRAD PACS looks up the prefetch worklist and begins downloading the matching studies in the background. eRAD PACS continues to prefetch data using your prefetch list after you sign off. The applied prefetch list changes when a new user logs in from the same workstation.  

 To activate prefetching:

1. Set up the filter criteria listing with the studies to automatically download
2. Save the filter
3. From the Other Lists page, select the Configure Prefetch   icon
4. Set desired parameters and select the Configure icon

When a user logs into a server from a workstation, the prefetch worklist is looked up and matching studies are downloaded in the background until the user signs off. The applied prefetch list changes when a new user logs in from the same workstation.

After defining the prefetch filters, prefetching must be enabled from the Viewer. Open the eRAD PACS viewer and check the Enable box in the Settings panel. Refer to the eRAD PACS Viewer Manual for details.

Prefetching performance and effectiveness start with a well-defined search.

Some suggestions for an efficient prefetch filter are as follows:

• The number of prefetch downloads of a studies per cycle is very limited, so keeping the N (number) within the 10-20 range is preferred.  A filter on the Date field equal to three or four times the prefetch cycle time should be sufficient.  

• Prioritize the studies by the sort order.  The prefetch list should place the newest studies at the top of the list which will download only the relevant studies.

• Inefficient filters can impact system performance if the query criteria is using object level fields, non-indexed fields or returns excessive number of matches. The user should apply prefetch filters from the Worklist page to confirm the results are returned quickly, modify the filter criteria and remove unnecessary fields/columns.

For more information on configuring a prefetch action, see: Configure Prefetch