Dental Radiography QA. Equipment Performance
The X-ray Set
X-ray sets must be checked and certified as working correctly when they are installed, and at regular intervals thereafter.
A specific person should be put in charge of arranging the equipment survey, and this should be done according to a regular timetable. They must also maintain a regular log of the performance checks, and list the actions taken to remedy any shortcomings.
There are three main phases of testing.
1. Critical examination of installation plans,
2. The Acceptance Test. When new equipment has been installed, and is about to be used for the first time.
3. Routine Tests. These are undertaken at timetabled intervals.
Is there any other time a “Routine Test” needs to be done?

After any significant maintenance procedure.
Critical examination of installation plans
This is done to check the plans meet radiation safety standards for staff, patients, and members of the public.
Who does this?

A qualified expert in radiation physics or medical physics.
What needs to be considered?

The main points are:
• Location, including checking that radiation can not escape for example through floor and walls in the x-ray room.
• The position of the operator when taking an x-ray.
• Warning signs and alarms.
• Access to the Exposure Control.
• Safety cut-outs, and the ability to electrically isolate the equipment in an emergency.
The Detailed Acceptance Test
This test covers the same ground as the critical examination. It also tests that the equipment works properly, and the precise dose from each machine is recorded.
Why is the actual dose recorded? Why not just record that it is within correct levels?

The precise measurements provide a baseline for the future, to check the dose does not increase with time.
Routine Tests
The frequency of routine tests varies in different countries. In the UK, the timetable should be at least every 3 years. If there have been any problems with dose, image quality, or running the QA programme effectively, this should be increased.
What is the aim of the routine test?

To establish that the equipment continues to operate optimally with respect to staff and patient safety by comparing it to the results of the acceptance test.
Are automatic processors included in tests?

Yes. Poor developing is a commonly compensated by increasing the dose to get a correct density image.
The results of all tests must be recorded (logged) in the Radiation Protection File. Actions needed to correct problems must be listed, and a record made of when they are completed.
The Radiation Protection File is an essential part of the Practice Clinical Governance Record (i.e. being able to prove, through documentation, that things are done well).
Next: Dental Radiography: QA. Diagnostic Reference Levels (DRL)