Once you have a technique chart that is reliable for your x-ray unit, and you have regular maintenance for your processor, chemistry and film cassettes, you should know right away if something goes wrong with your x-ray unit.
Many times, the technique chart you get with an x-ray unit, whether it is new or used, doesn't seem to work quite the way you would expect. I will not go into the reasons for this, but it is best to develop your own technique chart. To get the consistency and quality you want.
Let's review how to develop a technique chart. If you have a used x-ray unit or you wish to update your technique chart, I would recommend buying a radiologic technique kit. The sole purpose of the kit is to allow you to calculate technique and to develop a technique chart. If you purchase the complete kit, which includes both a calculator and a penetrometer, you can develop a technique chart. If you do not purchase a penetrometer, it is impossible to develop a technique chart unless you have kept the technical factors you've used for this machine on a good number of patients. You might be able to work backwards to find a correction factor, but I would not recommend this.
Borrow or buy a penetrometer. The express purpose of the penetrometer is to perform a series of x-ray exposures on your x-ray system (including the generator, tube, collimator, screens/film and processing) to determine the ability of you standardized set of exposure densities. From this comparison comes a total correction factor, which is used to determine optimal radiographic exposures for any body size or part. Once you've determined the total correction factor, anyone who understands how to use the calculator can determine what factors to use for any patient. It also allows you to predetermine which factors to use for any size patient. This way, you can determine ahead of time if a patient's density is too much for your unit, and you can refer the patient to a facility that can perform whatever series you need. Having a technique chart also allows you to determine if something is happening to your unit calibration before you frustrate yourself with poor quality x-rays.
An alternative you might wish to explore is to request assistance from the film manufacturer or the company from which you purchased the x-ray unit. Many of the reputable manufacturers and companies will send their personnel on site to expose anthropomorphic or water phantoms. This exposure information is then sent to the parent company. A computerized exposure chart is produced which is specific for that x-ray unit and the processing/film/screen combination. Many times, this service is free for the continued use of that manufacturer's film products. In my experience, if this type of chart does not produce consistently good results, it is more likely a problem related to the calibration of the x-ray generator or processing problems, such as improper temperature for development or inaccurate replenishment rates.
Some of the new high-frequency equipment offers preprogrammed exposure techniques as an option, with the added benefit of reduced patient exposure. Again, if you are not getting consistently good results from the program, it is most likely that something is wrong with the calibration of the x-ray generator or processing of the films.
If you still are having technical problems after you have performed some of these suggestions, you may wish to contact the American Chiropractic College of Radiology; your local diplomate of the American Chiropractic Board of Radiology; your local medical or health physicist, or even your state regulatory agency.
Once you have a reliable technique chart, you need to keep your film processing consistent. Here are some procedures you can follow to maintain your x-ray "department":
- Have the calibration checked on your x-ray unit periodically (every 2-3 years).
- Make sure you warm up the x-ray tube before taking exposures. This is not so important with the new high-frequency units, but if you have an old unit and would like to get as long a life out of the tube as possible, I would recommend you warm it up first before using a very high exposure time or kVp.
- Have a regular schedule for cleaning your cassettes (at least once a year).
- Change your chemistry in the processor at least once a month. (The less you use it, the more frequently you should change the chemistry. Just run it regularly. Even if you're not taking x-rays, run old film through to replenish the chemistry and keep the rollers from freezing from chemical buildup.)
- Clean the rollers daily, or at least every day you're in the office.
- Check the darkroom for light leaks at least once a year.
- Keep a log with patient measurements and techniques used. If this begins to change, it can indicate problems with the x-ray unit.
If you are able to keep a regular office procedure with the x-ray department, you'll avoid many of the aggravations caused by poor maintenance and neglect.
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