6.4.2
Reject analysis
A simple and valuable
tool in clinical image QC is reject analysis. Over a specified time period, a
record is kept of radiological examinations that are rejected and that require repeats
to be performed, with the date and the reason for the rejection (e.g. area of
interest not imaged, image blurred etc.) and the cause if known (e.g. incorrect
positioning, patient movement etc.). This allows the calculation of the
proportion of examinations which are rejected over a specified period and the
identification of the most frequent causes of rejection. Reject analysis can be
carried out prospectively (as images are performed) and/or retrospectively.
When performed retrospectively, this procedure is a form of Clinical Audit,
which requires assessment against a clearly defined set of Quality Standards.
Table 6.1 provides a means of comparing CBCT examinations against a standard.
Table 6.1:
Clinical Quality Standards for CBCT images
A.
Adequate patient preparation, positioning and instruction
·
No removable metallic foreign bodies which might
produce scan artefacts (e.g. earrings, spectacles, dentures)
·
No motion artefacts
·
No evidence of incorrect positioning of imaging
guides/stents (e.g. air gap due to incorrect seating of the stent)
·
Where fixed, metallic, restorations are in the
teeth, no artefacts overlying the area of primary interest1.
|
B.
Correct anatomical coverage
·
Evidence that the smallest Field of View available
on the equipment has been used, consistent with the clinical application.
·
The primary area of interest2 at or near the
centre of the Field of View.
·
All of the area of interest included in the scan
volume.
|
C.
Adequate exposure factors used
·
Absence of significant image noise, low density
and contrast
|
1It is
recognised that it may not always be possible to exclude restoration-related
artefacts, but there should be evidence that every effort has been made to
limit their impact (e.g. by careful orientation of the occlusal plane during
positioning).
2e.g. single
tooth or single implant site. It is recognised that where multiple implant
sites or larger structures are being imaged, not all can be central in the
scan volume.
|
The European Guidelines
on Radiation Protection in Dental Radiology (2004) recommended that, as part of
a Clinical Audit of film rejects, conventional radiographs be assessed into one
of three categories: “Excellent” (no faults), “Acceptable” (some faults but not
affecting image interpretation) and “Unacceptable” (faults leading to the
radiograph being unacceptable for interpretation). Furthermore, a minimum
target was set that no more than 10% of radiographs should be of unacceptable
quality. As stated above, the higher radiation doses often seen with CBCT
compared with conventional dental radiography imply that a more rigorous
quality standard may be appropriate. No published studies on reject rates for
dental CBCT examinations were identified by literature review. The only
available recommendation identified in this area was that published in the UK
(Health Protection Agency, 2010), which recommended a performance standard
(minimum target) of not greater than 5% of CBCT examinations classified as
“Unacceptable”. The SEDENTEXCT Guideline Development Panel concluded that this
was a pragmatic recommendation in the absence of published evidence of reject
rates with CBCT. The achievement of this target of 5% should not be seen as an
excuse to relax efforts to improve quality or cease image quality assessments.
Clinical Audit should be a cycle of quality improvement, relying on repeated
assessments against quality standards and implementation of change. Table 6.2
considers corrective actions that might be taken as part of a Clinical Audit
cycle.
|
Establishments
carrying out CBCT examinations should perform reject analysis, either
prospectively or as part of retrospective clinical audit, at intervals no
greater than once every six months
GP
|
As a minimum
target, no greater than 5% of CBCT examinations should be classified as “unacceptable”.
The aim should be to reduce the proportion of unacceptable examinations by
50% in each successive audit cycle
GP
|
The European Guidelines
on Radiation Protection in Dental Radiology (2004) recommended that, as part of
a Clinical Audit of film rejects, conventional radiographs be assessed into one
of three categories: “Excellent” (no faults), “Acceptable” (some faults but not
affecting image interpretation) and “Unacceptable” (faults leading to the
radiograph being unacceptable for interpretation). Furthermore, a minimum
target was set that no more than 10% of radiographs should be of unacceptable
quality. As stated above, the higher radiation doses often seen with CBCT
compared with conventional dental radiography imply that a more rigorous
quality standard may be appropriate. No published studies on reject rates for
dental CBCT examinations were identified by literature review. The only
available recommendation identified in this area was that published in the UK
(Health Protection Agency, 2010), which recommended a performance standard
(minimum target) of not greater than 5% of CBCT examinations classified as
“Unacceptable”. The SEDENTEXCT Guideline Development Panel concluded that this
was a pragmatic recommendation in the absence of published evidence of reject
rates with CBCT. The achievement of this target of 5% should not be seen as an
excuse to relax efforts to improve quality or cease image quality assessments.
Clinical Audit should be a cycle of quality improvement, relying on repeated
assessments against quality standards and implementation of change. Table 6.2
considers corrective actions that might be taken as part of a Clinical Audit
cycle.
Establishments
carrying out CBCT examinations should perform reject analysis, either
prospectively or as part of retrospective clinical audit, at intervals no
greater than once every six months
GP
|
As a minimum
target, no greater than 5% of CBCT examinations should be classified as “unacceptable”.
The aim should be to reduce the proportion of unacceptable examinations by
50% in each successive audit cycle
GP
|
6.4.3 Audit against established clinical
image quality criteria
Visual grading of anatomical features on medical images
is a standard method of assessing image quality. Criteria have been established
for several types of medical imaging, including adult and paediatric
radiography and CT (Report EUR 16260, 1996; Report EUR 16261, 1996; Report EUR
16262, 1999). The aim of such criteria is to characterize a level of
acceptability of medical images which can address any clinical indication.
The image quality
criteria established for CT (Report EUR 16262, 1999) have little relevance to
dental CBCT and there are no comparable established criteria for image quality
assessment for the wide range of uses of dental CBCT. Loftag-Hansen et al
(2010) described sets of statements used by observers in their study to assess
the adequacy of clinical image quality for two uses in upper and lower jaws: implant
planning and periapical diagnosis. In their study, these statements proved to
be a useful tool in optimisation of radiation doses and can be seen as a good
example of how image quality criteria for CBCT might be used. There is,
however, a need for further research to develop a comprehensive set of image
quality criteria for CBCT that reflect the range of equipment types and their
varying clinical capabilities. Ideally, this should be done at a European level
rather than various national criteria, as this would assist equipment
manufacturers in their work. Until such time as this has been accomplished,
clinical image quality assessment must rely either upon the simpler methods
described in 6.4.1 and 6.4.2, or by the local development of image quality criteria.
Image quality
criteria should be developed for dental CBCT, ideally at the European level
GP
|
Fault category
|
Observed fault
|
Cause
|
Corrective action
|
Patient preparation
|
Streak artefacts over area of interest.
|
Failure to take out removable metallic objects before
scanning (e.g. dentures, earrings and other piercings).
|
·
Careful
pre-scanning procedures to observe and ask patients about removable objects.
|
Imaging stent not in the correct
anatomical position.
May be recognised by an air gap under the stent on
scans.
|
Inadequate care in placing the stent or an ill-fitting
stent.
|
·
Greater
care in positioning the stent and checking position prior to imaging.
|
|
Blurring of
image.
|
·
Patient
movement.
·
Failure
to instruct patient, or to judge suitability of patient for scanning.
|
·
Procedures
to instruct the patient to stay still.
·
Consider
past experience with patient’s cooperation and ensure careful observation of
patient during positioning.
·
Use
all available immobilisation aids (head restraints, chin rest, etc).
|
|
Patient positioning
|
All, or part of, the area of interest excluded from the
scan volume.
|
·
Failure
to position the scan volume over the area of interest during preparation.
·
Patient
movement between initial positioning and exposure.
·
Field
of View too small for the diagnostic task.
|
·
Use
all available positioning aids (e.g. light beams). Omission of scout views
should only be considered under highly selected situations and where
alternative positioning aids are fully employed.
·
Protocol
to instruct the patient to stay still.
·
Use
all available immobilisation aids (head restraints, chin rest, etc.).
|
Streak artefacts over area of
interest.
|
The source of streak artefacts is in the same plane as
the area of interest.
|
·
Consider
tipping the head to reduce the impact of artefacts from non-removable objects
(dental restorations).
|
|
Exposure
|
Increased “graininess” and reduced sharpness of the
image.
|
Exposure factors too low (kV, mA, reduced number of
basis images).
|
·
Establish
exposure protocols to match patient size and the clinical purpose of
examination.
|
Post acquisition manipulation error
|
Poor contrast and brightness.
|
Using the image data as acquired, with failure to
optimise the contrast and brightness.
|
·
Operator
training Appropriate use of density and contrast controls.
|
“Pseudoforamina” in volume-
rendered images.
|
Incorrect thresholding.
|
·
Operator
training Appropriate use of windowing controls.
|
|
Incomplete diagnostic
information or exclusion of area
of interest on reconstructed
images.
|
Inappropriate positioning or thickness of reformatted
image slices.
|
·
Operator
training in multiplanar reformatting
|
6.5:
References
Advies van de Hoge
Gezondheidsraad nr. 8705. Dentale Cone Beam Computed Tomography. Brussel: Hoge
Gezondheidsraad, 2011. www.hgr-css.be
Council Directive 97/43/Euratom of 30 June
1997 on health protection of individuals against the dangers of ionizing
radiation in relation to medical exposure Official Journal of the European
Communities No L 180/11 1997
European Commission 2004. Radiation Protection 136.
European Guidelines on Radiation Protection in Dental Radiology. Luxembourg:
Office for Official Publications of the European Communities,. Available from: http://ec.europa.eu/energy/nuclear/radioprotection/publication/doc/136_en.pdf
IPEM 2005 Recommended standards for the
routine performance testing of diagnostic X-ray imaging systems IPEM report 91
Haute Autorité de Santé. Tomographie
Volumique a Faisceau Conique de la Face (Cone Beam Computerized Tomography).
Rapport d‟évaluation Technologique. Service évaluation des actes
professionnels. Saint-Denis La Plaine: Haute Autorité de Santé, 2009. http://www.has-sante.fr
Health Protection Agency Recommendations for
the design of X-ray facilities and quality assurance of dental Cone Beam CT
(Computed tomography) systems HPA-RPD-065 JR Holroyd and A Walker. Chilton:
Health Protection Agency, 2010a.
Health Protection Agency. Guidance on the
Safe Use of Dental Cone Beam CT (Computed Tomography) Equipment. HPA-CRCE-010.
Chilton: Health Protection Agency, 2010b.
Lofthag-Hansen S, Thilander-Klang A, Gröndahl
K. Evaluation of subjective image quality in relation to diagnostic task for
cone beam computed tomography with different fields of view. Eur J Radiol. 2010
Oct 19. [Epub ahead of print]
Qualitätssicherungs-Richtlinie – QS-RL.
Richtlinie zur Durchführung der Qualitätssicherung bei Röntgeneinrichtungen zur
Untersuchung oder Behandlung von Menschen nach den §§ 16 und 17 der
Röntgenverordnung. Gemeinsames Ministerialblatt 37-38, 2004, S. 731-777.
Report EUR 16260. Carmichael JHE, Maccia C, Moores BM,
Oestmann JW, Schibilla H, Teunen D, van Tiggelen R, Wall B. (Eds.). Quality
Criteria for Diagnostic Radiographic Images. Luxembourg: Office for Official
Publications of the European Communities, 1996.
Report EUR 16261. Kohn MM, Moores BM,
Schibilla H, Schneider K, St. Stender H, Stieve FE, Teunen D, Wall B. (Eds).
European Guidelines on Quality Criteria for Diagnostic Radiographic Images in
Paediatrics. Luxembourg: Office for Official Publications of the European
Communities,1996.
Report EUR 16262. Menzel H-G, Schibilla H,
Teunen D, (Eds.). European Guidelines on Quality Criteria for Computed
Tomography. Luxembourg: Office for Official Publications of the European
Communities, 1999.
Statens strålevern. Stråleverninfo 8:2010.
Krav for bruk av Cone Beam CT ved odontologiske virksomheter. Østerås: Statens
strålevern, 2010.
Sundhedsstyrelsen. Statens Institut for
Strålebeskyttelse. Krav til 3D dental. Herlev: Statens Institut for
Strålebeskyttelse, 2009.
7: STAFF PROTECTION
The general comments on
protection of staff made in the European Guidelines No 136 (European Commission
2004) are equally applicable to dental CBCT. However, as dose levels and beam
energies are generally higher compared to conventional dental radiology, extra
practical protection measures are required for dental CBCT. It is essential
that an appropriate qualified expert is consulted both prior to installation
and on an on-going basis.
|
It is essential
that a Qualified Expert is consulted over the installation and use of CBCT to
ensure that staff dose is as low as reasonably achievable and that all
relevant national requirements are met
ED D
|
7.1
Classification of areas
The European Guidelines
No 136 (European Commission 2004) recommended that the use of distance to
reduce dose was normally the only measure required for conventional dental
radiography. Data on dose rates around CBCT units are not available in the
literature, but doses measured in the field and information available from
manufacturers indicate that the maximum dose at 1 metre due to scattered
radiation varies between 2 to 47 Sv per scan, compared with intraoral and
panoramic radiography scatter doses of less than 1 Sv per exposure.
In addition, tube
voltage can be as high as 120kVp, leading to scattered radiation being
significantly more penetrating. This is much higher than conventional dental
radiography and the increased penetration through protective shielding must
also be borne in mind.
Consequently, it is
recommended that CBCT equipment be installed in a purpose-built enclosure
providing adequate protection to adjacent areas and the operator and that the
whole of this enclosure be designated a controlled area.
CBCT equipment
should be installed in a protected enclosure and the whole of the enclosure
designated a Controlled Area
D
|
7.2
Design of the CBCT room
7.2.1 Protection for adjacent areas
It is essential that shielding be provided to control
dose in areas adjacent to the CBCT room. This is recognised in national
guidance (HPA 2010a; HPA 2010b; Advies van de Hoge Gezondheidsraad, 2011;
Statens strålevern 2010). Advice on the design of CBCT facilities has been
published by the UK Health Protection Agency (HPA 2010a, HPA 2010b) and
provides guidance for the qualified expert on aspects that must be considered when
designing a dental CBCT facility.
The amount of scattered
radiation per scan depends on a number of factors, and neither kV nor maximum
FOV are good predictors of this. Furthermore, the dose distribution may not be
uniform in all directions around the CBCT equipment. The HPA (HPA 2010a) report
that the maximum scatter dose at a distance of 1m can range from 2 to 40 Gy per
scan. Measurements carried out by SEDENTEXCT partners confirmed this range,
although the majority of units gave readings between 6 to 12 Gy per scan.
Detailed information, e.g. in the form of secondary radiation plots, should be
sought from the supplier or manufacturer to allow the calculation of
appropriate levels of shielding.
In calculating
shielding, the workload of the unit also needs to be taken into consideration.
For dental practice, the HPA (HPA 2010a) suggest that a workload of 20 scans
per week be assumed, while for a hospital department the figure would be 50
scans per week. A review of workload within the SEDENTEXCT partners again
confirms these assumptions as reasonable for current practice, although it must
be born in mind that the clinical use of dental CBCT is still developing and
workload assumptions should be kept under review.
Working to a dose
constraint of 0.3 mSv per year to staff in adjacent areas, shielding up to
1.5mm lead equivalence will be required in the walls provided that the unit is
positioned so that the distance to staff in the adjacent area is 1m or greater.
However, due to the significant differences in maximum operating potential and
levels of scattered radiation, many installations may be satisfactorily
shielded with lower requirements. It is likely that doors, which will normally
be further away from the unit, could contain less protection. In addition,
floor and ceiling protection needs to be considered and it is likely that
ground floor windows will need blocking up. A dose constraint of 0.3 mSv per
year is in accord with Danish and UK requirements (Sundhedsstyrelsen 2009; HPA
2010b). Alternative national guidance exists but is in broad agreement with
this. In Norway, a dose constraint of 0.25mSv per year is established, with
shielding equivalent to 1mm lead considered satisfactory where equipment
operates below 100kV. Where equipment operates at higher kiloVoltage, the
Norwegian guidance recommends that it may be necessary to increase the
protection to 3mm lead equivalent, depending on workload, room size and design
and the frequency of use of neighbouring rooms. The input of the qualified
expert in determining protection needs is advised (Statens strålevern, 2010).
Detailed
information on the dose due to scattered radiation should be obtained to
inform decisions about shielding requirements
D
|
Table 7.1: Summary of
shielding requirements at 1 m for dose constraint of 0.3 mSv per annum
7.2.2 Room layout
The operator position should be outside the room or, if
inside, be provided with additional shielding in the form of a protective
cubicle to stand behind. The position of the operator must always be such that
they can clearly see the patient and the room entrance(s) and be able to
interrupt the scan using the emergency stop, if required. This might be via a
protected viewing window, a strategically positioned mirror or with the use of
a CCTV camera. The emergency stop should be located adjacent to the operator,
positioned so that the operator does not need to enter the room unprotected in
order to activate it (HPA 2010 a, HPA 2010b).
For units requiring authorisation of the
exposure from the computer software prior to exposure, it is essential that the
computer should be located close to the X-ray unit rather than over a network
to reduce the likelihood of the exposure being authorised without the operator
at the CBCT control.
CBCT units usually require that the mains power supply be
left on, to obviate the need for a lengthy warm up procedure before each
exposure. If another unit is located in the same room, the layout should be
arranged to reduce the likelihood of the wrong unit being initiated; for
example, by providing exposure switches in separate locations or by placing the
exposure switches in lockable boxes. Safeguards should also be incorporated
into the exposure initiation systems to ensure that the equipment cannot be
operated by people not authorised to do so. This can be achieved by the use of
password or key control (HPA 2010a).
A system of warning
lights is recommended for dental CBCT units, in line with local regulatory
requirements for X-ray rooms; ideally providing a two stage indication: stage 1
to indicate readiness to expose (i.e. when the power is switched on to the
unit) and stage 2 when X-rays are about to be or are being generated (HPA
2101b).
7.3
Personal Monitoring
Routine personal
dosimetry for dental radiographic staff is generally considered desirable but
not universally necessary across all European countries. (European Commission
2004). Given the higher dose levels when using dental CBCT units, the need for
personal monitoring should be carefully considered, seeking the advice of a
qualified expert if available.
The provision of
Personal Monitoring should be considered
D
|
7.4
References
Advies van de Hoge Gezondheidsraad nr. 8705.
Dentale Cone Beam Computed Tomography. Brussel: Hoge Gezondheidsraad, 2011.
www.hgr-css.be
European Commission 2004. Radiation
Protection 136. European Guidelines on Radiation Protection in Dental
Radiology. Luxembourg: Office for Official Publications of the European
Communities,. Available from: http://ec.europa.eu/energy/nuclear/radioprotection/publication/doc/136_en.pdf
European Commission 1996 Council Directive
96/29/Euratom of 13 May 1996 laying down basic safety standards for the
protection of the health of workers and the general public against the dangers
arising from ionizing radiation Official Journal of the European Communities L
159/1
HPA 2010a Recommendations for the design of X-ray
facilities and quality assurance of dental Cone Beam CT (Computed tomography)
systems HPA-RPD-065 JR Holroyd and A Walker Health Protection Agency
HPA 2010b Guidance on the Safe Use of Dental
Cone Beam CT (computed tomography) Equipment HPA-CRCE-010
Statens strålevern. Stråleverninfo 8:2010.
Krav for bruk av Cone Beam CT ved odontologiske virksomheter. Østerås: Statens
strålevern, 2010.
8: ECONIMIC EVALUATION
Economic evaluation
attempts to weigh costs and effects of alternative interventions with the goal
that available resources are used to achieve maximum benefits for patients in
terms of health and quality of life. In emerging technologies, this is
particularly important to avoid inappropriate and excessive use. As part of the
systematic review process described in this document, no literature was
identified that fell under the heading “cost effectiveness” or “economic
evaluation”. A few studies mentioned the costs of CBCT, usually quoting the
hospital fee for a CBCT examination. Such figures do not usually reflect real
costs and reflect idiosyncrasies of particular hospitals and healthcare
systems.
As part of the
SEDENTEXCT project, the Malmö University partner has led the research on health
economic evaluation and has commenced a broader systematic review to analyse
evidence on economic evaluation in oral health care, particularly as relates to
diagnostic methods. Studies identified by literature search were interpreted by
two reviewers using a check-list for assessing economic evaluations (Drummond
et al. 2005). Of four publications presenting diagnostic interventions in oral
health care, only one publication remained after the reviewers‟ interpretation.
This publication (Norlund et al. 2009) presented a model analysis of the cost
of true-positive occlusal dentine caries detection in permanent molars assessed
by different diagnostic strategies using bitewing radiography. Thus, no
publication that presented an economic evaluation of CBCT was identified with
the aid of the systematic review.
At the time of
writing, cost analysis carried out within the project is unpublished. There are
data on cost-analysis collected from examinations of maxillary canines with
eruption disturbances that shows that CBCT is more costly than conventional
examinations with intraoral and panoramic radiography. A comparison of costs of
CBCT-examinations within different health care systems of patients with
different clinical conditions showed that estimates for costs varied for
examination of one and the same condition between the health care systems.
Thus, valuation of costs in monetary terms of CBCT should not be generalized
from one health care system to another but a model for cost analysis similar to
that designed within the project provides an important tool for economic
evaluations in comparing costs and consequences of diagnostic methods and can
guide planning of service delivery in both public and private sectors.
Considering the results obtained, the use of CBCT needs to involve a
comprehensive assessment of economic factors in conjunction with radiation
dosage, diagnostic accuracy efficacy and the benefits for the patients in terms
of health and life quality in different health care contexts.
Economic
evaluation of CBCT should be a part of assessment of its clinical utility
GP
|
8.1 References
Drummond MF, Sculpher MJ, Torrance GW,
O´Brian BJ, Stoddart GL. Methods for the economic evaluation of health care
programmes. Oxford: Oxford Medical Publications, 3rd ed, 2005.
Norlund A, Axelsson S, Dahlén G, Espelid I,
Mejàre I, Tranaeus S, Twetman S. Economic aspects of the detection of occlusal
dentine caries. Acta Odontol Scand 2009;67:38-43.
9: TRAINING
9.1 Roles and responsibilities
As defined in the European Directive (Council
Directive 97/43/Euratom, 1997), the roles involved in delivering a diagnostic
radiological service to patients are:
The Holder: any natural or legal person who has the legal
responsibility under national law for a given radiological installation.
The Prescriber: a medical doctor, dentist or other health professional,
who is entitled to refer individuals for medical exposure to a practitioner, in
accordance with national requirements. The prescriber is involved in the
justification process at the appropriate level.
The Practitioner: a medical doctor, dentist or other health professional,
who is entitled to take clinical responsibility for an individual medical exposure
in accordance with national requirements.
The medical physics expert (MPE): an expert in radiation physics or radiation
technology applied to exposure, within the scope of the Directive, whose
training and competence to act is recognized by the competent authorities; and
who, as appropriate, acts or gives advice on patient dosimetry, on the
development and use of complex techniques and equipment, on optimization, on
quality assurance,
including QC, and on other matters relating to radiation
protection, concerning exposure within the scope of the Directive.
In hospital practice, these roles are usually
straightforward to link to particular individuals; the Holder is the Hospital
or Health Service Authority, the Prescriber is the health professional carrying
out the patient‟s clinical care, the Practitioner is usually a radiologist and
a MPE is appointed to provide specialist support. In primary dental care,
however, the first three of these roles are frequently held by one individual.
“Self referral”, where the dentist is both Prescriber and Practitioner, is
normal. An MPE may, or may not, be normally appointed to a dental practice
depending on national regulations.
In addition to these roles, the practical aspects for the
procedure, or part of it, may be delegated by the holder of the radiological
installation or the practitioner, as appropriate, to one or more individuals
entitled to act in this respect in a recognized field of specialization. In
hospital practice, this may include a radiographer/ imaging technician, but in
primary dental care it may involve the dentist or a dental assistant/ nurse. In
the current document, any role involved in practical aspects for the procedure
will be referred to by the term “Operator”.
The
Directive requires that Member States shall ensure that practitioners and the
other individuals mentioned above have adequate theoretical and practical
training for the purpose of radiological practices, as well as relevant
competence in radiation protection. Where a relatively new technology such as
CBCT is concerned, the Panel recognized that existing training of users may be
less than ideal and that appropriate arrangements for training must be made. As
stated in Section 3 of this document, this is considered a “Basic Principle” of
the use of CBCT in dentistry.
All those
involved with CBCT must have received adequate theoretical and practical
training for the purpose of radiological practices and relevant competence in
radiation protection
ED BP
|
A key part of continuing education and training is identification of those most capable of delivering it. Specialists in Dental and Maxillofacial Radiology, with their unique combination of a dental and a radiological training, are likely to be the most appropriate individuals to deliver much of the training, in conjunction with medical physicist support.
Continuing
education and training after qualification are required, particularly when
new CBCT equipment or facilities are adopted
BP
|
|
Dentists and
dental specialists responsible for CBCT facilities who have not previously
received “adequate theoretical and practical training” should undergo a
period of additional theoretical and practical training that has been
validated by an academic institution (University or equivalent). Where
national specialist qualifications in Dental and Maxillofacial Radiology
exist, the design and delivery of CBCT training programmes should involve a
Dental and Maxillofacial Radiologist
BP
|
9.2 Curricula for training in CBCT
While the content of training programmes
aimed at delivering “adequate theoretical and practical training” are most
appropriately determined nationally within Member States, the Guideline
Development Panel involved in devising the “Basic Principles” of the use of
CBCT in dentistry (Horner et al, 2009) endorsed a draft core curriculum to
provide a basic structure and content for training (Table 9.1). The Guideline
Development Panel recognised the large national variation in Europe in the
clinical services provided by dentists in primary care.
Role
|
Training content
|
The Prescriber: a dentist referring a patient for CBCT
and receiving images for clinical use
|
Theoretical instruction
·
Radiation
physics in relation to CBCT equipment
·
Radiation
doses and risks with CBCT
·
Radiation
protection in relation to CBCT equipment, including justification (referral/
selection criteria) and relevant aspects of optimisation of exposures
·
CBCT
equipment and apparatus
Radiological interpretation
·
Principles
and practice of interpretation of dento-alveolar CBCT images of the teeth,
their supporting structures, the mandible and the maxilla up to the floor of
the nose (e.g. 8cm x 8cm or smaller fields of view)
·
Normal
radiological anatomy on CBCT images
·
Radiological
interpretation of disease affecting the teeth and jaws on CBCT images
·
Artefacts
on CBCT images
|
The Practitioner: a dentist responsible for performing
CBCT examinations
|
Theoretical instruction
·
Radiation
physics in relation to CBCT equipment
·
Radiation
doses and risks with CBCT
·
Radiation
protection in relation to CBCT equipment, including justification (referral/
selection criteria), optimisation of exposures and staff protection
·
CBCT
equipment and apparatus
·
CBCT image
acquisition and processing
Practical instruction
·
Principles
of CBCT imaging
·
CBCT
equipment
·
CBCT
imaging techniques
·
Quality
assurance for CBCT
·
Care of
patients undergoing CBCT
Radiological interpretation
·
Principles
and practice of interpretation of dento-alveolar CBCT images of the teeth,
their supporting structures, the mandible and the maxilla up to the floor of
the nose (e.g. 8cm x 8cm or smaller fields of view)
·
Normal
radiological anatomy on CBCT images
·
Radiological
interpretation of disease affecting the teeth and jaws on CBCT images
·
Artefacts
on CBCT images
|
In parallel, or
subsequently, guidelines on dental CBCT have been developed nationally in
Belgium (Advies van de Hoge Gezondheidsraad, 2011), Denmark (Sundhedsstyrelsen,
2009), France (Haute Autorité de Santé, 2009), Germany (Leitlinie der DGZMK,
2009; Schulze & Schulze, 2006), Norway (Statens strålevern, 2010) and the
United Kingdom (Health Protection Agency, 2010). These incorporate
recommendations for training in varying detail. Authorities in other European
countries are in the process of developing their own national guidelines.
In France, the relevant “Basic Principles”,
Nos.16-20 (Section 3) have been reiterated (Haute Autorité de Santé, 2009). In
Norway, the emphasis is placed upon “relevant and documented competence” in
radiological interpretation, in physics and in operating equipment. It is a requirement
in Norway that a radiologist is employed by a dental practice carrying out CBCT
examinations, but that limited volume CBCT (definition as given in Table 9.1
and in Basic Principle No.19 in Section 2) can be interpreted by a dentist with
relevant and documented competence if the radiologist allows it (Statens
strålevern, 2010). The need for training so that competence is achieved is
therefore implicit.
More detailed training curricula have been
devised in Denmark, Germany and the UK. In the Danish guidance, the dentist
responsible must have the supplementary training needed to interpret the CBCT
images, while all personnel who work the units must have instructions on how to
operate them. The requirements for training include a practical course with
training of the responsible dentist and personnel on how to operate the units
and also further education of the responsible dentist in the theoretical
background for CBCT imaging. The German course concept includes supervised
practical training in interpretation, theoretical training, personal study and
an examination. The UK guidance document includes a detailed curriculum for
theoretical training which differentiates between the training needs of those
in Prescriber, Practitioner and Operator roles, and which recommends
supplementary training in operating CBCT equipment ideally given by a trained
applications specialist from the equipment manufacturer. The recommended
duration of training in these national guideline documents varies considerably.
In the light of these differing national
developments in training curricula, and recognising the widely varying
traditions in different countries, the Panel concluded that it was
inappropriate to recommend a more detailed curriculum than that described in
Table 9.1. National authorities should build upon this “core” curriculum in a
manner which satisfies their specific needs.
There is no comparable curriculum or guidance
for medical physics experts on the specific training needs for CBCT. It is
clear that a MPE will have substantial existing knowledge, but that CBCT has
some unique characteristics that necessitate additional training. While this
training might be obtained by self-study, consideration should be given to
developing CBCT learning opportunities for MPEs so that they can familiarise
themselves with the specific requirements.
CBCT
applications specialists and agents of manufacturers and suppliers of CBCT
equipment who provide information and training to clinical staff should
obtain relevant training in radiation protection and optimization
GP
|
9.3
References
Advies van de Hoge Gezondheidsraad nr. 8705.
Dentale Cone Beam Computed Tomography. Brussel: Hoge Gezondheidsraad, 2011.
www.hgr-css.be
Council Directive 97/43/Euratom of 30 June
1997 (on health protection of individuals against the dangers of ionizing
radiation in relation to medical exposure).
Haute Autorité de Santé. Tomographie
Volumique a Faisceau Conique de la Face (Cone Beam Computerized Tomography).
Rapport d‟évaluation Technologique. Service évaluation des actes
professionnels. Saint-Denis La Plaine: Haute Autorité de Santé, 2009. http://www.has-sante.fr
Health Protection Agency. Guidance on the
Safe Use of Dental Cone Beam CT (Computed Tomography) Equipment. HPA-CRCE-010.
Chilton: Health Protection Agency, 2010.
Horner K, Islam M, Flygare L, Tsiklakis T,
Whaites E. Basic Principles for Use of Dental Cone Beam CT: Consensus
Guidelines of the European Academy of Dental and Maxillofacial Radiology.
Dentomaxillofac Radiol 2009; 38: 187-195.
Leitlinie der DGZMK. Dentale
Volumentomographie (DVT) - S1 Empfehlung. Deutsche Zahnärztliche Zeitschrift
64, 2009: 490 - 496.
Schulze D, Schulze R. Kurskonzept zur
Vermittlung der Fachkunde der dentalen digitalen Volumentomographie für
Neuanwender. 2006 [Personal Communcation].
Statens strålevern. Stråleverninfo 8:2010.
Krav for bruk av Cone Beam CT ved odontologiske virksomheter. Østerås: Statens
strålevern, 2010.
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