© PACS Configuration ©

• Configuring a radiology workstation must take into account the radiologist's preferences, functions and the type of image to be viewed. Any design configuration decision must provide a cost benefit solution. Designing a workstation is going to vary with each site and is dependent upon both individual preference and physician function. Not every diagnostic station has to be 2K, if a radiologist only interprets small matrix images there is no need of the more expensive 2K units. There is also no need of greater than eight monitors for any one unit yet four or six will usually do.

• Particular attention must be given to lighting and placement of the workstation.
• Lighting should be reflected (indirect), and controllable. There must be no chance of direct light applied to the monitor and the ambient room brightness is adjusted to the radiologist's preference. A good way to do this is by using wall sconces or ceiling to wall reflected light.
• Placement of workstations is critical. Workstations should be placed so that no two have a direct opposite placement. Proper placement reduces the reflection from one workstation onto another. Workstations should be placed, if possible, in a semi circular format with the room entrance facing the radiologist, preventing outside reflection and reducing intermittent shadows created by hallway traffic.

CLINICAL WORKSTATION

Clinical workstations fall into two categories, Clinical-Diagnostic and Clinical-Reference, each having the same basic configuration yet differing in patient care level application. The first category, Clinical-Diagnostic, is defined by the specific uses of the Critical Care and Emergency Departments. Both have a higher level viewing need than the nursing unit which is where a Clinical-Reference is indicated. Commonly the CCU and ED workstation directly relates to how the patient will be treated while the Clinical Reference is used more as a report to image correlation.

Restricting the placement of workstations relevant to clinical application will save a tremendous amount of money. Typically the Clinical-Diagnostic station should be purchased from a PACS vendor while the Clinical-Reference can be an integrated workstation provided by the HIS vendor. This is dependent upon the HIS vendor having a true HIS-RIS-PACS interface.

ARCHIVE

Archives are actually very simple to configure. It is much the same as a film library, yet there is one obvious difference; it is now electronic. The same decisions must be made regarding how much space is needed and how fast an access is needed. Physical space is not the limiting factor of an electronic archive. Physically a digital archive can hold approximately 10 years of images in a 12 X 12 room, dependant upon environmental conditions. The limiting factor for digital archives is retrieval needs. The archive configuration can be broken into two pieces - Size and Configuration and Design.

Size

To size the archive is very simple - convert the current exams into digital data size formats. All equipment vendors can provide you with the actual DICOM size of the images that are produced. Break your volumes down by modality IE. CT, MRI, US, NM, Angiography, Fluoroscopy, Diagnostic etc.. Follow this exercise to get annual and then total archive needs:

• Calculate the average number of Images per Exam (A),
• From your vendor get the DICOM image size, this will be in Bytes, (B),
• Multiply A x B to get average exam size, in Bytes (C),
• Multiply C times the Modality Volume which will give you your annual data needs (D),
• Add up all the Modalities to get a total annual archive need (E), most like will come out in Giga or Tera-Bytes,
• Multiply E times your retention statute which will give you total archive size needs, excluding growth factors and patient mix.

Every facility should take into account the average experienced/projected growth as well as patient mix. Facilities with high Pediatric usage are going to need a much larger archive because of the longer retention statute. You may want to separate Pediatrics out like any other modality and add that in as a permanent fixture to the archive needs - IE take the pediatric volumes and multiply that times 24 (Satisfies most pediatric statutes of Majority + 3 ) and use this as a base size for the archive and then add everything else to this.

Configuration and Design

I recommend setting up a two tiered archive: live and permanent. The live being configured utilizing a RAID structure and then going straight to TAPE; when I first published this web page I would not have recommended this structure, but with the changes in pricing and tape speed it is now more than feasible. The RAID archive should be located onsite but the TAPE archive could be anywhere, remember - Disaster Recovery.

NETWORKS

My advice is to use fiber as much as possible and to have a dedicated Imaging Network. Currently the limiting factor to image transmission speed is the workstation design not the network. Workstation speed will change with time and fiber has theoretically no limit relative to speed. A dedicated imaging network gives the assurance of no outside interference or data collisions. Additionally the chosen network must be redundant, never ever let someone talk you into running your image network over the same network as your IS, the amount of information you will be transmitting will choke it.

I was recently asked "Is there such a thing as too much redundancy?" I would unequivocally say yes. A PACS is inherently better than the current manual operations in most facilities. Looking at the way Radiology does business now, as far as handling and storing film, PACS does a far superior job. If a backup for the backup for the backup ETC. is created then allot of financial resources are wasted that could be utilized to increase the image network.

I also recommend the network management be turned over to the MIS department. A radiology director does need the additional headache of trying to keep the image network up, because as sure as the sun rises it will eventually go down. This does not imply that radiology must be divorced from monitoring the network. There must always be open lines of communication between Radiology and MIS. Each department must keep the other aware of any and all technology changes.