The humungously large NHS IT project known as Connecting for Health is set to be late and delivered over budget. We are set for bad news as more details of this secretive set of projects leak out. But it is nor all bad news. In fact one aspect of it is set to be a rousing success - and as details come out it is hard not to agree that this will be the case.

The project is called PACS - Picture Archiving and Communications Systems - and it is to do with the capture, storage and delivery of digitised medical images, In the typical situation a medical image is printed on film. The classic situation is an X-ray. The X-ray is stored as film in the hospital facility where it was taken and when a patient sees a doctor that X-ray must be present. There is only one copy. Obviously this limits what can be done with X-rays.

There are other kinds of medical image:-

- photographs
- Ultra-sound scans
- CT scans
- MRI scans
- Microfiche records(DICOM)

These images are captured at different places within a hospital. They are stored in different ways - modalities in the NHS jargon - and they suffer from an obvious limitation. Generally patients and doctor and image have to come together for a consultation. Stored images can't travel and there is generally only one copy.

The PACS idea, based on existing practice in the USA is:-

- Move to digitised images, meaning one modality,
- Store them on disk, meaning multiple copies can easily be made,
- Send then across a network to viewing systems, meaning a PC attached to a server.

PACS is very simple from a storage point of view. Files are stored on a central online drive array. The thirst for capacity is steadily increasing but not radically so. For us in the storage world, and for us as private consumers of digital photos, this is so obviously a good idea that it needs no discussion at all. There is no need for film processing. There is no need for multiple viewing systems, such as microfiche readers, X-ray lightboxes, and so forth.

Images can travel to patient and doctor wherever they are. Multiple copies can be seen at once if needed. Lost images should become extremely rare events. Image retrieval and display can be relatively quick with no more waiting for a porter, for example, to fetch X-rays from the hospital X-ray library. It all means that a patient's condition should be diagnosed faster and at less expense.

The then Health minister John Hutton said in May, 2004: "The digital image will follow the patient wherever they go and will be able to be recalled whenever and wherever they need to be accessed by a patient's healthcare professional."

In the UK the NHS IT programme, now known as Connecting for Health, has five contracts with local (regional) service providers (LSPs). Each group of hospitals in a region is known as a cluster. Images will be communicable between all hospitals in a cluster. Patients in rural areas will especially benefit as PACS viewing systems will be put into minor injuries units and other diagnostic locations, saving them on lengthy trips to hospitals.

The five LSPs are:-

- Southern cluster - Fujitsu and GE
- London Cluster - Phillips with BT
- East and East Midlands - Accenture with GE
- North East Cluster - Accenture with Agfa
- North West and West Midlands Cluster - CSC with GE.

Connect for Health supremo Richard Grainger said: "We have negotiated a substantial reduction in the average price of a PACS system." It's understood that there has been a 57 percent reduction on diagnostic workstations, a saving of 60 percent on image acquisition equipment, a massive 71 percent reduction on the disk storage side and an 80 percent lowering of server costs.

Typically a supplier, such as Phillips, supplies the PACS hardware and software. A systems and communications consultancy implements this into the regional hospitals' IT and network system. The PACS software includes an image management system and an image database. Data protection functionality is also included.

In the Phillips PACS system images are stored on a RAID 5 disk vault. They are communicated across a WAN to viewing systems with so-called wavelet technology being used to reduce the bandwidth needed. The communicated images are sent in a lossless way so that no detail is left out.

Hospital and inter-hospital network links are a bit of a patchwork and there is limited network bandwidth to take into account.

The image vault is a form of network-attached storage and were basically talking about a filer/NAS silo holding the multifarious images. For example, the AGFA PACS product uses NetApp filers. SANs have been used also. ONstor has supplied NAS-based PACS storage to US hospitals, also a NAS head with anIBM SAN behind it.

All UK hospitals should be PACS-upgraded by the end of 2008, implementations taking place at a rate of one a week. The Southern Cluster, covering Cornwall to Kent, is where the deployment of PACS is most mature. There are 17 trusts in the cluster now live with PACS and the cluster data store is also live, enabling images to be shared. So far over 26 million images have been stored in it and more than 1.6 million patient examinations using PACS have takem place in the southern cluster.

From the storage point of view this is all trivial. A RAID 5 disk array is a piece of commodity technology. A NAS filer is also a commodity. It is gratifying that such obviously beneficial technology is being put in place in the NHS.