Safety and Health Office
phone: 6488 3938, fax: 6488 1179
WORKING RULES FOR OHCWA INTRA-ORAL DENTAL X-RAY UNITS
Working rules are essential to ensure that all intra-oral dental x-ray units are used in accordance with
legal requirements and with a high standard of safety for patients, staff, students and others.
1. Intra-oral dental x-ray units may only be operated by a qualified dentist, by dental ancillary
personnel (Refer 2) under the direction and supervision of a dentist, or by a qualified
radiographer on the instructions of a dentist or medical practitioner, and only for the
purposes of intra-oral radiography and lateral oblique radiography of the mandible. No other
person is authorised to operate these units and they must not be used for any other purpose
than the above.
2. Dental ancillary personnel means a person who has satisfactorily completed a Radiological
Council approved radiation safety training course.
3. These units are not to be operated or used for human diagnostic radiography unless
covered by a current Certificate of Compliance.
4. Note that the default exposure value when turning on the unit is the adult bitewing mode.
5. Select and fit the collimator (cone) to be used. It is recommended that the long collimator
(cone) be used whenever possible in order to keep the absorbed dose to the patient as low
6. The exposure values must be selected according to the collimator (cone) used the image
mode, adult/child, exposure region, time and kV (these are usually pre-programmed).
7. Ask the patient to sit down (if not already seated) and position the dental chair appropriately.
Place a protective lead apron over the patient’s torso.
8. Position the film/sensor and collimator (cone) as required; it is recommended that a beam
guidance instrument should be used whenever possible for all diagnostic films (e.g. the Rinn
9. When taking a radiograph, ensure the patient remains as still as possible. Move as far away
from the x-ray tube as the length of cable permits. No one except the patient may remain in
the radiation area whilst the exposure is taken. Operators and observers should be standing
at least two metres from the patient’s head during exposures and conscientiously using any
protective shielding provided. In instances where there is no protective shielding, stand at
least 2 metres from the patient, at an angle of 90° to 135° to the central x-ray beam.
10. Maintain visual contact with the patient and x-ray unit during the exposure.
11. Check that the ready light is on. Press and hold the exposure key on the control panel for
the duration of the exposure. The exposure warning light will come on and an audible
warning sound should accompany the exposure. Do not release the exposure key until the
light goes off and the warning sound stops to indicate that the exposure has been
12. Immediate measures must be taken to remove potentially hazardous situations arising from
x-ray beams that may be emitted due to an equipment defect, misalignment or any other
reason. It is recommended that each x-ray unit is switched off after use.
13. The OHCWA School Radiation Safety Officer (SRSO) is: Winthrop Professor Paul Abbott
14. Servicing of x-ray machines may only be carried out by a technician with a suitable license
from the Radiological Council.
15. All incidents and injuries must be reported to the SRSO and UWA Safety and Health Office.
If the machine is faulty, do not use it, tag it out and report it for repair.
16. These working rules are to be prominently displayed beside the x-ray unit control panel at all
17. For further information please refer to the OHCWA Radiography Policy