Jane Renehan on x-ray units

Jane Renehan answers another question from a reader – this time, she’s busting some myths about hand-held portable X-ray devices.

The question – Dear Jane…

Are hand-held portable X-ray devices a like-for-like substitute for a wall-mounted intraoral X-ray machines?

The answer

Hand-held X-ray equipment should not be considered as a replacement for fixed or semi-mobile intraoral units. This is a direct quote from EPA’s (Environmental Protection Agency) code of practice on the application of ionising radiation regulations in dentistry (2019). 

EPA’s guidance is in line with the international expert body HERCA (Heads of the European Radiological Protection Competent Authorities).

In 2014, HERCA issued a position statement stating that the use of hand-held devices should be discouraged except in special circumstances. Situations such as nursing homes, residential care facilities, forensic dentistry, and military operations were considered as settings where the units are most suited.

Authorisation 

All radiological facilities must receive an authorisation from EPA prior to being put into use. There are two types of authorisation:

  1. Registration for low risk units – lasts indefinitely (unless surrendered or revoked) and self-declaration confirming compliance with requirements must be submitted with applications
  2. Licensing for potentially higher risk equipment – lasts 10 years and risk assessment, additional safety procedures and other EPA-specified information must be submitted with applications.

EPA’s code of practice is very clear that hand-held devices have the potential to result in higher doses to both the operator and members of the public than conventional intra-oral units. 

Patient exposure may also be a concern, and image quality could be compromised mostly because of the necessity for longer exposure times due to lower tube current, difficulties in using rectangular collimation with beam aiming devices, weight of the unit and use in uncontrolled environments.

For this reason, hand-held devices, uniquely amongst dental X-ray equipment, are subject to licensing. This imposes additional legal obligations on the practice owner with respect to authorisation cost, operator training, secure storage, documentation, and communications with EPA. 

It is noted that the higher the risk, the more likely the equipment is to attract practice inspection. 

Authorisation fees

Most dental practices pay a registration fee of €300 which is a once off charge. By contrast, the fee for a licence is €1000 when hand-held X-ray equipment is on the premises. There is also a licence renewal fee payable every 10 years. For full details on fees, practice owners should contact the EPA directly.

Operator training

Manufacturers of hand-held devices routinely include instructional videos with a new unit. Such training videos usually award a certification to verify that the viewer has undertaken the instruction. A record of user training must be maintained. Documentation providing evidence of this training may be requested by an inspector. Training videos from the major manufacturers are freely available online.

Training will demonstrate that hand-held units must always be held level, and parallel to the ground. The operator will learn that the circular backscatter shield on the tube head provides maximum protection when held in a horizontal plane. The operator needs to become proficient at angling the patient’s head to ensure that the device is held level with the floor. 

X-ray safety procedures

A separate section on the hand-held unit is required in the practice radiation safety procedures and local rules. The RPA’s advice will be critical in preparing or updating the safety procedures. 

The practice owner should implement the new procedures, ensuring that day-to-day operation of the hand-held unit is in accordance with the licence conditions and the advice of the RPA.

The terms of the licence will designate the dental surgeries in which the unit may be used. It should not be used outside these locations without prior approval of the EPA and RPA.

Security

When not in use, the hand-held unit should be locked and switched off. At the end of the treatment session the battery should be removed and stored in its case in a locked cupboard. The cupboard key should be held at a secure location.

Conclusion

In summary, a hand-held portable device is not a substitute for a conventional intraoral X-ray unit. My advice to any dentist considering the purchase of a hand-held unit is to take time in advance doing the research, and always speak with your RPA. 

What may seem initially attractive, could in the longer-term result in financial, training, procedural and regulatory challenges. 

It is the responsibility of the buyer to perform due diligence before making the purchase. Caveat emptor – let the buyer beware. This is especially important when it comes to hand-held X-ray units. 


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