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Changing to digital radiography

by
01 September 2011, at 12:00am

JUDY SCRINE describes her transition from holding x-rays in developer, fixer and wash tanks to an automatic processor and now into the word of digital processing

IT is a sad thing that I am sufficiently of dinosaur vintage to have been approached to write an article about the evolution of xraying from chemical tank developing to full digital radiography. This evolution has been similar I feel to my grandmother living through from travel by pony and trap to man landing on the moon. As I began my career in 1991, many multiples of four minutes were spent holding x-rays in developer, fixer and finally wash tanks. Not fun when the horse was standing there impatiently with a fourinch needle somewhere near his navicular bursa, and however careful I was to avoid contact with the noxious fluids, somehow I always ended up smelling of them (the fixer was the worst). Not helpful on first dates, though better than “cleansing cow” smell I guess. As I moved into equine only practice, I also moved from chemical tanks to the automatic processor – which seemed a fabulous thing at the time. The plate could be fed in one end, and if you were lucky and the machine played ball, a nicely developed, nonscratched x-ray would come out reasonably quickly from the other. There were the times the plate got stuck and had to be retaken – annoying enough, or even more annoying when two plates got stuck together and both got ruined. The Law of Sod decreed that the more important the x-ray, and the more difficult it was to take, the more likely it was to get spoilt in the automatic processor. These machines drank chemicals with gay abandon, required draconian cleaning regimes and still smelt of chemicals. There was the issue of how to dispose of these chemicals, and whether it was worth trying to reclaim the silver in the developer or not. A significant environmental issue! Storing hard copy x-rays was very space-consuming and a fire-hazard, and if there had been anything less than ideal chemical processing, the images tended to decay in storage.

Sharing problems

Posh hospitals did have means to copy x-ray plates taken this way, otherwise xrays could only be shared by either taking extra plates (increasing x-ray exposure of personnel and subject) or by sending the precious originals elsewhere, probably never to be seen again. It was a great day, therefore, when we made the leap into computed radiography (CR). It was an expensive leap for a small first opinion practice such as ours, but one which we did not regret. Suddenly, exposure factors were less critical, images could be manipulated, zoomed into, text added. The system still required use of individual plates, limiting the number of images one could take in the field. The greatest advantage was that these images could be digitally stored, and copied onto CD or e-mailed. Expert opinions could be sought virtually instantly once the images were on computer. The clients could have copies for their own records, for insurance companies, for their farriers or for other veterinary surgeons should they wish to seek second opinions or move to another veterinary practice. This was somewhat of a doubleedged sword. X-ray images had previously belonged to the radiologist –
the client merely paying for the opinion rather than the images themselves. Once copies of images are handed over to the
client, unless they are prevailed upon to sign some (probably unenforceable) confidentiality agreement, they can do with them as they will. Not that we are trying to hide anything, of course, but much easier for supersession to occur. 

Plenty of thought 

We did think long and hard as to whether the cost of the move on from CR to digital radiography was worth the advantages: £55,000 was a fortune to a small practice like ours, but we went for it and purchased BCF’s “Tru DR” system (and a generator) via a lease scheme. Suddenly, even the time it took for processing CR plates seemed long, when compared to the three seconds or so it took for the DR image to appear. X-raying for needle placement was no big deal. Whole x-ray series could be done in less than half the time. There was no limit to the number of plates that could be taken – a huge advantage, for example, with prepurchase examination x-rays or survey radiography for fractures. Images taken in the field could be checked there and then and repeated if necessary, rather than the horrible shock of finding a non-diagnostic image on return to the clinic from a far-flung yard.

Same charge

We continued to charge the same price for x-raying. Occasionally clients claim that DR images should be cheaper
because no materials are used to produce them, but are usually easily silenced when told the cost of the kit. We take care to explain the advantages of DR imaging when presented with this situation. There are still problems if one is pedantic. The lovely American voiceover lady is enough to drive you to drink (but apparently can be turned off!). The machine certainly has its moments, especially if you try and rush it. The wire connections to the laptop seem unnecessarily fragile considering the use expected of the machine and inevitably the most expensive bit is the one you wave near the animal. Plate holders can be used but are cumbersome and put the expensive bit at risk, so usually the assistant holds the plate and is therefore near the main beam and the kicking bits of the subject. The wire between the unit and the plate has high “memory” and can be a nuisance, plus is not capable of standing up to 600kg of horse parked on it. The area of interest on the plate is actually quite small, particularly for areas such as horse skulls, or stifles. Being able to rapidly take another image should not be an excuse for lackadaisical positioning, and adequate restraint should still be used. Whilst the processing allows manipulation of exposure factors, it cannot correct for excessive movement or poor positioning. Avoiding over-exposure of the subject or the personnel is still important. Do we regret going digital? Absolutely not! The conversion from the CR was easy once a few teething problems were ironed out. We use two different generators with our DR, each with their own cable to interface with the DR unit. We can still use the generators for CR as well if necessary, merely by changing the cable. We finally took the brave step some time ago of throwing away our automatic processor and remaining chemicals. Clients are very appreciative of the more efficient x-raying and increased scope of the DR over more conventional techniques, especially in the field. They are thrilled to be able to see the images so quickly at “horseside”.  DR has significantly enhanced the radiography service we can offer. The ability to refer the images to specialists and sending e-mail copies to clients, insurance companies and farriers has literally revolutionised our practice. We carry out significantly more radiographic examinations now, particularly with prepurchase examinations and for assessment of cases which can’t travel to the clinic, for whatever reason. Whilst we are lucky enough to have a clinic base, many of the other equine practices in the area are purely ambulatory, so many clients are used to radiography being carried out in the yards and prefer this option. 

Increase in turnover

It is hard to say whether the machine has paid for itself: saved veterinary time, improved image quality, increased service to clients, increased numbers of radiographic examinations carried out and “keeping up with the Joneses” all need to be factored in. I haven’t done the figures precisely, but the percentage of the practice turnover that comes from imaging has definitely increased, as has the total turnover. Our lease arrangement will be paid off over a five-year period from initial purchase. Because the load is so well spread, paying the lease has not been too painful. Many ambulatory practices have a DR unit in each of the vet cars – an understandable requirement especially
for practices carrying out a lot of pre-purchase examinations. There is certainly wrangling amongst the five vets of our practice as to who gets to take the DR. I would strongly encourage any veterinary practitioner teetering on the edge of
going digital to take the plunge. Roll on more affordable DR units – we might be persuaded to approach the bank again.