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radiography – local rules

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introduction

Every dental practice with radiographic (x-ray) equipment is required to provide a set of “local rules”.  These record all the working practices we must follow to ensure that we are safe when working with radiation and that we comply with the various regulations governing radiation in dentistry; in particular the Ionising Radiations Regulations 2017 (IRR17).  This document contains the “local rules” that apply to Hygeia Dental Care’s premises at Malt Mill Lane, Totnes.

management and supervision

Joanne Giddy is ultimately responsible for ensuring compliance with IRR17 and has put together the radiation protection programme (documented in the Radiation Protection file) to achieve this.

In order to ensure that the arrangements in these local rules are followed, a Radiation Protection Supervisor (RPS) has been appointed.

The RPS is Joanne Giddy. The RPS should ensure that all dental radiography is carried out in accordance with these local rules.

It is the responsibility of the RPS to periodically review and (in consultation with the RPA/MPE – see below) update these local rules.

radiation protection adviser and medical physics expert

Public Health England Dental X-ray Protection Services (formerly known as the Health Protection Agency Radiation Protection Division; formerly known as the NRPB) has been appointed as Radiation Protection Adviser (RPA) and Medical Physics Expert (MPE) to Hygeia Dental Care in respect of its premises at Malt Mill Lane, Totnes in accordance with Regulation 14 of IRR17 and Regulation 14 of the Ionising Radiation (Medical Exposure) Regulations 2017 as amended by the Ionising Radiation (Medical Exposure) Regulations 2018 (“IRMER”), respectively.  Our primary contact is Sharon Ely.  She can be contacted on 0113 212 7430.

training

The RPS (Joanne Giddy) is responsible for ensuring that any staff that operate the x-ray equipment are appropriately trained. Section 1 of the Radiation Protection file details the training requirements, staff training records and the personnel register (which indicates who is able to operate the x-ray equipment).

All new members of the team receive essential training in relation to the local rules as part of their induction process; the RPS (Joanne Giddy) must also ensure that existing members of the team maintain their knowledge of the local rules.

duties of employees

All clinical personnel must:

a) Ensure that exposures to staff and all other people are kept as low as reasonably practicable;
b) Take reasonable care when working with any aspect of dental radiography – in particular, radiography must be conducted with due regard to minimising accidental or unintended doses to patients;
c) Immediately report to the RPS (Joanne Giddy) any incident that may result in the overexposure of themselves or anyone else.

All clinical personnel have a duty to exercise reasonable care and act responsibly in relation to radiography.  They are required to know and observe these rules at all times.

x-ray equipment at Malt Mill Lane

There are two x-ray units at Malt Mill Lane:

unit 1

location treatment room 1
manufacturer Trophy Trex
model IRIX 70 – Trophy CCX
serial no. 875097
manufactured 23/6/98
installed 15/10/98
operating potential 67kV
total beam filtration >2.0mm Al
beam profile 33mm x 42mm (with collimator)
focal spot to skin distance 200mm
optimum dose for imaging 0.97mGy (digital sensor – adult mandibular molar)
patient skin dose 0.41mGy (digital sensor – film type 5 – adult mandibular molar)

unit 2

location treatment room 2
manufacturer Trophy Trex
model IRIX 70 – Trophy CCX
serial no. 921048
manufactured 20/7/99
installed 8/99
operating potential 71kV
total beam filtration >2.3mm Al
beam profile 32mm x 42mm (with collimator)
focal spot to skin distance 200mm
optimum dose for imaging 0.89mGy (digital sensor – adult mandibular molar)
patient skin dose 1.10mGy (digital sensor – film type 6 – adult mandibular molar)

 

important note:   The garden area outside must be unoccupied whilst x-rays are being taken.

It is the responsibility of Joanne Giddy (the RPS – see below) to notify the Health and Safety Executive of the use of, and any changes to, the radiography equipment in use at the premises.

controlled and supervised areas

The IRR specify “controlled” and “supervised” areas in relation to dental intra-oral x-ray equipment.

controlled areas

When either x-ray unit is operating, a “controlled area” exists.  A controlled are is somewhere that you MUST NOT GO while the x-ray unit is in operation.  When an x-ray is being taken in surgery 1, the whole of that room is a controlled area.  When an x-ray is being taken in surgery 2, the whole of that room is a controlled area.

supervised areas

There are no supervised areas outside the controlled areas defined above.  All that clinical personnel need to know about supervised areas is that there are none.  Just be sure to stay out of the controlled areas when the x-ray unit is in operation.

classified persons and written system of work

There are no “classified persons” on our team and the provisions on written systems of work do not apply.

x-ray equipment – testing, servicing, maintenance & repair

NOTE: Service, maintenance and repair work should only be undertaken by adequately qualified service engineers (see below for details).

All x-ray units at Malt Mill Lane must be subjected to a radiation safety assessment at least once every 3 years.  It is the responsibility of the RPS (Joanne Giddy) to ensure that this is done.  Radiation safety assessments are carried out using standard HPA test packs.  It is the responsibility of the RPS (Joanne Giddy) to ensure that any recommendations made as a result of the assessments are acted upon within 3 months.

All x-ray units at Malt Mill Lane must undergo routine servicing at least once every year.  It is the responsibility of the RPS (Joanne Giddy) to ensure that this is done.  Servicing is undertaken by Edwards Dental who can be contacted on 01803 555739 or 07921 101111.

All x-ray units at Malt Mill Lane must undergo routine surveillance at least once every 6 months.  Routine surveillance checks the correct functioning of the audible and visual warning systems, exposure controls, x-ray arm counterbalance mechanism and condition of the x-ray tube head.  It is the responsibility of the RPS (Joanne Giddy) to ensure that this is done and to arrange for any necessary repairs to be carried out.  Repairs are undertaken by Edwards Dental who can be contacted on 01803 555739 or 07921 101111.

Computer monitors used to view x-ray images at the practice (which means all of them) undergo testing every 3 months to ensure that they are correctly calibrated and reproduce images with good detail, contrast and without distortion.  The results are recorded in section 7 of the Radiation Protection File.  Monitors that do not perform acceptably must be replaced.

Digital x-ray sensors and imaging software used to capture x-ray images undergo testing every 3 months to check sensor condition, image uniformity, low contrast sensitivity and sensor dose response.  The results are recorded in section 7 of the Radiation Protection File.  Sensors (or software) that do not perform adequately must be replaced.

No-one is permitted to interfere with or modify any part of the x-ray equipment unless they have first referred the matter to the RPS (Joanne Giddy).

Following any testing, servicing, maintenance or repair work, no x-ray unit or ancillary equipment may be accepted back into service until the RPS (Joanne Giddy) has reviewed the service report.  This should confirm that the equipment has been left in a state fit for use and that no alterations have been made which may significantly affect patient doses.  If such alterations have been made, the RPS (Joanne Giddy) should seek advice from the RPA/MPE before bringing the equipment back into use, since a critical examination may be required first.

use of x-ray equipment/working procedures

The x-ray equipment must only be operated by a suitably qualified person, or by a person under their supervision who has received adequate training and instruction in the use of the x-ray equipment.  At Malt Mill Lane only Joanne Giddy is qualified to operate the equipment.

The exposures used for radiography must be no greater than those required to yield correct radiographic densities with complete development of the film.  The exposure timings for both x-ray units are pre-set.  The correct film speed settings are selected using the “f” button on the control box.  The practice uses digital sensors.  The correct setting for these is film type 3 in surgery 1 and film type 6 in surgery 2.  The controls must also be set for the appropriate anatomical view.  For other film types and guidance on adjustments to exposure times to compensate for patient size, refer to the IRIX 70 user’s manual.

The operator of the x-ray equipment must take up a position outside the main x-ray beam and where the instantaneous dose rate does not exceed 7.5 microsieverts per hour.  For both x-ray sets the appropriate operator position during exposures is outside the door of the room.  The operator must ensure that they are able to view both the warning light on the control hand-switch and the patient during radiography.  Electronic viewers installed on the doors permit the operator to view the patient from outside the room.  The hand-switch controlling the exposure is on an extendable curly-cable and is brought outside the room by the operator so that the warning light remains visible. The audible warning tone is also easily audible from outside the controlled area and the operator must listen to ensure that the tone sounds and terminates as appropriate.

For intra-oral radiography, the primary x-ray beam (IE the tube head) must never be directed toward the operator. The operator must also ensure that the primary x-ray beam is never directed toward a window, an unshielded door or an unshielded partition wall.  If this appears to be the case, the patient must be repositioned before the exposure is taken so that the tube head is pointing toward an external wall or shielded internal wall.

The operator must ensure that no-one except the patient is present in the controlled area when x-rays are being produced.

The operator is supplied with and is required to use x-ray film holders with integral beam alignment devices.  These have been proven to reduce the number of radiographs that are judged unacceptable by reason of positioning errors, thereby reducing the overall number of x-rays taken and x-ray exposure for clinical personnel and patients alike.

During every radiographic examination the operator must observe the radiographic warning light to check that the exposure terminates correctly.

X-ray sets must be turned off at the mains (using the switch on the control panel) after each set of radiographs.
When the surgery is not in use the x-ray set must also be turned off at the local consumer unit in the room (circuit breaker number 3 – labelled “X-ray unit”): this must be done as part of the closing-down process at the end of each working day.

damage to x-ray equipment

If an x-ray unit is damaged, immediately isolate the unit from the mains electricity supply.  To do this, simply switch the power off using the switch on the front panel of the x-ray control unit.  The x-ray control unit is the box on the wall near the surgery entrance door (to which the remote switch is attached).  Next, switch off the supply circuit labelled “X-ray unit” (circuit breaker number 3) at the consumer unit in the relevant surgery.  Notify the RPS (Joanne Giddy) of the damage immediately.  Do not use the x-ray unit again until the malfunction has been investigated by the RPS (Joanne Giddy) and any necessary remedial action has been taken by service agents.  Servicing is undertaken by Edwards Dental Equipment Services who can be contacted on 01803 555739 or 07921 101111. The RPS must also inform and consult the RPA/MPE.

contingency plans

If the exposure warning light remains on after the set time has elapsed, or any other fault is indicated or suspected, immediately isolate the x-ray unit from the mains electricity supply.  To do this, simply switch the power off using the switch on the front panel of the x-ray control unit.  The x-ray control unit is the box on the wall near the surgery entrance door (to which the remote switch is attached).  Next, switch off the supply circuit labeled “X-ray unit” (circuit breaker number 3) at the consumer unit in the relevant surgery.  Notify the RPS (Joanne Giddy) of the malfunction immediately.  Do not use the x-ray unit again until the malfunction has been investigated by the RPS (Joanne Giddy) in consultation with the RPA/MPE, a satisfactory explanation has been found and remedial action has been taken by service agents.  Servicing is undertaken by Edwards Dental who can be contacted on 01803 555739 or 07921 101111.

If any of the above contingency plans are used, the RPS (Joanne Giddy), in consultation with the RPA/MPE, should analyse the cause of the event to determine if any action is required to prevent a recurrence of the incident.  A record of the analysis should be made and kept for at least two years.  If any person receives a radiation exposure as a result of the incident this should be noted on any relevant dose record.

significant unintended or accidental exposure

If it is suspected that a patient undergoing a medical exposure (or any other person) may have been exposed to ionising radiation to an extent much greater than intended, the incident must be reported immediately to the RPS (Joanne Giddy).  She must immediately consult with the RPA/MPE (ie the HPA) to determine an estimate of the patient dose. If the estimate of the patient dose indicates that the patient has been exposed to levels of ionising radiation significantly greater than those considered to be generally proportionate in the circumstances, the RPS (Joanne Giddy) will:

a) notify the Care Quality Commission (CQC)
b) arrange for a detailed investigation of the circumstances of the event and if necessary a more detailed assessment of the dose received
c) notify the Care Quality Commission within the specified time period of the outcome of the investigation and any corrective measures adopted.

If it is decided that the exposure is clinically significant, the RPS (Joanne Giddy) should discuss the exposure with the patient or the patient’s representative.

The investigation into the exposure should be documented together with the outcomes of the analysis, including estimated patient dose. The report should be retained in the Radiation Protection file and copies provided to the patient or the patient’s representative.

dose investigation level

The formal dose investigation level set by this practice is 1mSv (refer to Radiography Risk Assessment – see section on IRR, regulation 22: Dose Assessment).  If it is suspected that any member of staff’s effective dose has exceeded 1mSv within a calendar year, the RPS (Joanne Giddy) must conduct a formal investigation in liaison with the RPA/MPE in order to establish why.  The purpose of the investigation is to determine whether radiation doses are being kept as low as reasonably practicable. The results of any such investigation must be kept for at least 2 years.

pregnancy – clinical personnel

All clinical personnel must inform the RPS (Joanne Giddy) as soon as they become aware that they are pregnant.  This is because working with ionising radiation carries certain risks for a developing foetus.  Compliance with these local rules should normally mean that no special precautions are necessary.  However, the RPS (Joanne Giddy) will consult the RPA/MPE and, if required, implement changes to working practices for the pregnant team member to ensure that the dose to the foetus of any member of staff is unlikely to exceed 1mSv during the declared term of pregnancy.

pregnancy – patients

Pregnant patients only present safety issues in connection with dental radiography when a radiographic examination would result in irradiation of the pelvic area by the primary x-ray beam (eg where a vertex occlusal projection is required).  We do not use such projections on adult patients and therefore this can never be an issue.

Nonetheless, we always identify pregnant patients as part of our clinical risk management procedures by means of medical history taking (treatment code EMED1) and medical history updates (treatment code EMED2).

Where a patient knows or suspects that they are pregnant, then they are – unless there is an urgent need for treatment and radiographic examination is essential – advised that they may defer radiographic examination if they prefer. This should be documented in the patient’s record.

patient identification

Joanne Giddy is the RPS and is the only referrer/operator/practitioner for the purposes of IRMER at this practice. The only patients treated at the practice are her patients and she knows them all personally. Accordingly, there is no realistic possibility of a failure to correctly identify any patient and so we do not operate formal procedures for patient identification.

assistance with radiography

Practice personnel must never support the x-ray tube head, or the patient, or hold a sensor in position for the patient.

film processing

The practice no longer uses wet film systems, so all sections in older editions of these local rules relating to film processing, preparation of solutions, storage of solutions, replacement of solutions, processing times and temperatures and mounting of radiographs no longer apply.

radiographic quality control

When reviewing x-rays, the dentists must note any deterioration in image quality.  If there is any deterioration in quality, they must consider whether this is a result of errors in positioning or exposure.

Errors of positioning should be virtually eliminated by the beam alignment devices provided.  If not, the operator must adjust his or her technique to improve results.

Exposure times are pre-set on the x-ray units at the practice.  This minimises the possibility of error.

Processing errors are no longer possible (because we use a digital system), so a loss of image quality may indicate a malfunction in the x-ray unit or the digital x-ray sensor and the RPS (Joanne Giddy) must be informed.  It is her responsibility to investigate the matter and, if necessary, arrange for the x-ray unit, sensors and software to be checked if she suspects there may be a fault.  In her absence, the operator should consult the RPA.  If it is necessary to arrange for the unit to be checked, contact Edwards Dental on 01803 555739 or 07921 101111.

The practice aims to achieve the following x-ray quality targets:

a) Not less than 70% of x-rays should be of “excellent quality” – with no errors of exposure or positioning

b) Not more than 20% of x-rays should be of only “acceptable quality” – with some errors of exposure or positioning but which do not detract from the diagnostic utility of the radiograph

c) Not more than 10% of x-rays should be of “unacceptable quality” – with errors of exposure or positioning which render the radiograph diagnostically unacceptable

If an operator becomes aware that the quality of films has fallen significantly below these targets, they must inform the RPS (Joanne Giddy) immediately.  She must then take action to ensure that overall quality is improved.

The RPS (Joanne Giddy) is responsible for carrying out audits of radiographic image quality at six monthly intervals.  The results of these audits are recorded in our Radiation Protection File.  If the quality targets set out above are not met, she is responsible for taking action to ensure that overall quality is improved.

The practice also carries out biannual audits of reject x-ray images to determine the causes of clinically unacceptable images and to determine whether any patterns arise that may allow corrective action to be taken.

All x-ray images are graded as “excellent” (grade 1), “acceptable” (grade 2) or “unacceptable/reject” (grade 3) on the day they are taken and this is recorded in the patient notes.  This ensures that any changes in image quality are noted as soon as they occur.

clinical evaluation of x-rays

Every dental exposure undertaken must be clinically evaluated. Clinical evaluation of x-ray images is carried out by Joanne Giddy (who is also the RPS and is the only referrer/operator/practitioner for the purposes of IRMER at this practice) after the image is taken.  The image is captured using a digital CCD system and it is therefore available to view only a few seconds after the exposure.  Any caries revealed or other findings relevant to the patient’s management or prognosis are recorded in the patient’s electronic notes either during the course of or shortly after their appointment (IE at the end of the session). The clinical evaluation must bear the name of the dentist.

referral, justification and authorisation of x-rays

A clinical assessment of every patient’s teeth is performed prior to the taking of any x-rays.

Where the referrer also acts as the practitioner and operator for a dental exposure (as is currently always the case at Malt Mill), they must ensure that the request for the x-ray is documented within the patient’s dental record. The clinical indications for the x-ray should be clear and fit with the referral criteria mentioned below. The referrer must be identifiable in the notes.

This practice follows the procedures outlined in ss2.29 to 2.35 of “Guidance notes for dental practitioners on the safe use of x-ray equipment” published by the National Radiological Protection Board in 2001 and the more detailed good practice guidelines entitled “Selection Criteria for Dental Radiography” published by the Faculty of General Dental Practitioners (UK) of the Royal College of Surgeons of England, 3rd edition (2013). Copies of these documents are available in the office and also online.

This practice does not carry out x-ray exposures for purely medico-legal reasons nor at the request of third parties.

Each individual exposure must be justified, taking into account:

a) The specific objectives of the exposure and the characteristics of the individual involved
b) The total potential diagnostic or therapeutic benefits of the exposure, including the direct health benefits to the individual and the benefits to society
c) The individual detriment that the exposure may cause
d) The efficacy, benefits and risk of available alternative techniques having the same objective but involving less (or no) exposure to ionising radiation.

If the practitioner is aware, at the time of authorisation, that a recorded clinical evaluation shall not result from the exposure then the exposure must not be authorised and cannot take place.

When the referrer (who is also a registered dental practitioner and entitled IRMER practitioner) deems it in the patient’s best interests to have an x-ray then the referrer’s name in the clinical notes indicates that it is also deemed to be a justified exposure.

explanation of risks and benefits

The practitioner who undertakes the exposure is responsible for ensuring that the patient is informed about the benefits and risks associated with the radiograph prior to it taking place by describing the benefits to the patient in terms of the expected positive outcome from the radiograph and explaining that the risk is low.

The following words can be used: “The risks associated with dental radiography are negligible and the radiograph will help inform treatment decisions.”

To help put the risk into perspective, dental radiography can be compared to other exposure situations. For example: “The radiation from two bitewing radiographs is roughly equivalent to that received during a 1-hour plane flight.”

risk assessment

The practice is required to carry out, record and periodically review a risk assessment for work with x-rays.

It is the responsibility of the RPS (Joanne Giddy) to ensure that the risk assessment is reviewed, updated and any necessary action taken to maintain safe working practices and/or compliance with current regulations.  The risk assessment must be reviewed annually AND:

a) whenever new radiographic techniques or equipment are introduced for the first time (eg first use of panoramic radiography or cephalometry);

b) whenever there are changes to the process or methods of work;

c) whenever new legislation is introduced relating to radiography.

The latest risk assessment is published on this website.

disposal of radiographic waste

Since the practice now uses a digital x-ray system, we no longer produce the associated waste products: lead foil from x-ray wrappers, x-ray developer solution and x-ray fixer solution.

 

Web version 17: 16.7.2018
Previous local rules published: 27.7.2006; 10.4.2008; 9.8.2008; 2.4.2009; 26.1.2012; 23.2.2012; 27.4.2012; 17.12.2012; 13.3.2013; 19.6.2014; 11.4.2015; 3.7.2015; 4.8.2016; 20.10.2016 (reviewed 1.9.2017); 3.9.2017; 2.2.2018

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