Reference 43
Final Decision Analytic Protocol
(DAP) to guide the assessment of
Cone Beam CT for dental imaging
September 2012
Table of Contents
MSAC and PASC .................................................................................................................................3
Purpose of this document ..............................................................................................................3
Purpose of co-application ..................................................................................................................3
Background ........................................................................................................................................4
Current arrangements for public reimbursement .........................................................................4
Intervention .......................................................................................................................................6
Description of technology ..............................................................................................................6
Administration, dose, frequency of administration, duration of treatment .................................6
Co-administered interventions ......................................................................................................7
Description of patient population......................................................................................................8
Listing proposed and options for MSAC consideration .....................................................................9
Proposed MBS listing......................................................................................................................9
Clinical place for proposed intervention ......................................................................................10
Comparator......................................................................................................................................15
Clinical claim ....................................................................................................................................15
Outcomes and health care resources affected by introduction of proposed intervention .............18
Outcomes .....................................................................................................................................18
Health care resources ......................................................................................................................19
Proposed structure of economic evaluation ...................................................................................20
Reference List ..................................................................................................................................24
Page 2 of 29
MSAC and PASC
The Medical Services Advisory Committee (MSAC) is an independent expert committee appointed by
the Minister for Health and Ageing (the Minister) to strengthen the role of evidence in health
financing decisions in Australia. MSAC advises the Minister on the evidence relating to the safety,
effectiveness, and cost-effectiveness of new and existing medical technologies and procedures and
under what circumstances public funding should be supported.
The Protocol Advisory Sub-Committee (PASC) is a standing sub-committee of MSAC. Its primary
objective is the determination of protocols to guide clinical and economic assessments of medical
interventions proposed for public funding.
Purpose of this document
This document is intended to provide a draft decision analytic protocol that will be used to guide the
assessment of an intervention for a particular population of patients. The draft protocol will be
finalised after inviting relevant stakeholders to provide input to the protocol. The final protocol will
provide the basis for the assessment of the intervention.
The protocol guiding the assessment of the health intervention has been developed using the widely
accepted “PICO” approach (Richardson et al 1995). The PICO approach involves a clear articulation of
the following aspects of the research question that the assessment is intended to answer:
Patients – specification of the characteristics of the patients in whom the intervention is to be
considered for use;
Intervention – specification of the proposed intervention
Comparator – specification of the current intervention most likely to be replaced by the
proposed intervention
Outcomes – specification of the health outcomes and the healthcare resources likely to be
affected by the introduction of the proposed intervention
Purpose of co-application
A reference requesting consideration of Medicare Benefits Schedule (MBS) listing of Cone Beam
Computerised Tomography (CBCT) for dental and craniofacial imaging was received by the
Department of Health and Ageing (DOHA) in July 2010. A co-application requesting MBS listing of
CBCT for 21 indications reimbursable through four separate MBS descriptors (sinus and facial bones;
temporal bones, temporomandibular joint (TMJ) and internal acoustic meatus; dental and sleep
apnoea) was submitted by Dental and Medical Diagnostic Imaging (DMDI) to the Department of
Health and Ageing in March 2011.
This Consultation Decision Analytic Protocol (DAP) is restricted to three indications (detailed below)
which were identified as priority areas based on consultation with DOHA, the Royal Australian and
New Zealand College of Radiologists (RANZCR) and the Australian and New Zealand Association of
Oral and Maxillofacial Surgeons (ANZAOMS). These three indications also cover many of the 21
indications submitted by DMDI.
Page 3 of 29
Background
Current arrangements for public reimbursement
As part of the 2011-12 Budget, the Government announced that it would introduce an MBS interim
item from July 2011 for CBCT. Prior to this, CBCT had been indirectly reimbursed through the MBS
using a variety of combinations of item numbers for example: Diagnostic Imaging Services, Category
5, Group I3 - 60100 (tomography) in combination with x-ray items for the head and face (MBS items
57901 to 57945) and OPG MBS items (57960 to 57969) (Department of Health and Ageing & Megan
Keaney 2011).
Looking at the utilisation figures for the CBCT MBS Items 56025 and 56026, there were 12,871
attendances from 1 July 2011 to 30 September 2011, suggesting that CBCT is already widely used in
clinical practice.
Table 1 MBS Item for Cone Beam Computed Tomography (interim item)
* From 1 July 2011 all services listed in the Diagnostic Imaging Services Table of the MBS, excluding Positron Emission
Tomography services, preparation items 60918 and 60927 and MRI modifier items in subgroup 22, will have a mirror NK item
(50% of the Schedule Fee) for diagnostic imaging services provided on aged equipment. This rule, known as ‘capital
sensitivity’, is currently in place for CT and angiography and will be extended to improve the quality of diagnostic imaging
services by encouraging providers to upgrade and replace aged equipment as appropriate.
Page 4 of 29
Table 2 below details MBS utilisation for CBCT and associated procedures for the period April 2011September 2011. As can be seen, CT utilisation did not vary, however, the number of claims for
tomography dropped substantially with the introduction of the CBCT item numbers in July 2011.
Table 2 MBS Utilisation for CBCT and associated procedures
Regulatory status
CBCT devices vary in terms of capabilities and image quality
, and as such are listed accordingly on the Australian Register of Therapeutic Goods (ARTG). In the
first group are those machines that are designated as 3D CBCT and these are registered as either
for dental and medical imaging or for dental diagnostic imaging only (Hardman 2011).
In a second group are those machines that are 3D or 2D reconstructed hybrid cone beam volumetric
tomography with panoramic and cephalometric capabilities. These devices are included on the ARTG
as panoramic tomography devices with a cephalometic capability for dental use. Similarly a third
group includes hybrid machines that are included on the ARTG as panoramic tomography devices for
dental use only (Hardman 2011). At the April PASC meeting it was noted that given this range of
devices, it is important that the MBS descriptor specify the type of device that is eligible for
reimbursement of CBCT items.
It was agreed at the August PASC meeting that the MBS descriptor would cover CBCT or hybrid
machines provided they meet accredited performance characteristics consistent with dedicated CBCT
Appendix B outlines the minimum equipment requirements recommended by RANZAR for CBCT
machines.
Prior to July 2011, providers had been advised to register CBCT equipment as x-ray or
orthopantomography equipment and claim corresponding items on the Diagnostic Imaging Services
Table. Providers are now required to amend their location specific practice number to register (or reregister) CBCT equipment as CT (equipment code “GAN”). According to the applicant (DMDI), OPG
devices are not included on the ARTG as CBCT machines, as the manufacturer has intended the
device to be an orthopantomography (OPG) machine. For a manufacturer and sponsor to change
their intended use of a device the CE certifications for the device and application to the Therapeutic
Goods Administration (TGA) needs to be amended accordingly.
Page 5 of 29
Intervention
Description of technology
CBCT is a method to acquire 3D images through the use of a rotating gantry to which an x-ray source
and detector are fixed. In contrast to the fan shaped beams and multiple detectors used in multi-slice
CT, CBCT uses a cone-shaped x-ray beam with a flat panel detector to acquire images. Software
programs are applied to these image data to generate a 3D volumetric data set, which can be used to
provide primary reconstruction images in multiple planes (axial, coronal, sagittal, oblique, curved)
(White 2008). Hard structures such as teeth, jaws and skull are visualised well by CBCT due to
isotropic and high spatial resolution. However, imaging of soft tissues is poor due to low contrast
resolution, with the exception of the visualisation of soft tissue outlines such as the upper airway
(Lapp et al 2008; White 2008). CBCT acquires all images in a single rotation with a scan time
between 4.9 and 40 seconds. Some CBCT machines also allow the size of the irradiated area to be
reduced through collimation of the primary x-ray beam thereby minimising the radiation dose to the
patient.
While CBCT is a radiological imaging technique with a range of potential indications, it is particularly
suited to head, neck and dental applications and has primarily been used in this field.
This DAP relates to the use of CBCT for the following indications:

to assess bone quantity and quality as part of dental implant planning and in management of
suspected implant complications;

to assess structures identified clinically or on 2D radiographs as being in close approximation
to sites of planned dento-alveolar surgery that may be at risk of damage during surgery; and

further assessment of the dentition and associated dento-alveolar and TMJ pathology which
may not have been adequately assessed using two-dimensional radiographic techniques.
Administration, dose, frequency of administration, duration of treatment
CBCT units vary widely in size, cost, radiation dose and parameters such as the “field of view”
(imaging volume). “Field of view” (FOV) refers to the scan volume of the CBCT device and depends
on the size and shape of the unit, beam geometry and whether the beam is collimated (American
Association of Endodontists & American Academy of Oral and Maxillofacial Radiology 2010). There is a
close relationship between the FOV size and the radiation dose received by the patients; therefore it
is important that the smallest FOV is selected for each patient to capture all the required clinical
information. Large field of view CBCT units are currently used in radiology practices and public
hospital based dental units whereas smaller field of view CBCT units can be integrated into OPG units
for use in private dental surgeries and radiology practices which typically are referred to as ‘hybrid’
units.
CBCT services are subject to the current professional supervision rules for CT, which state that the
service must be performed under the professional supervision of a specialist in the specialty of
Page 6 of 29
diagnostic radiology who is available to monitor and influence the conduct of the examination, and to
attend to the patient personally if necessary.
Co-administered interventions
Patients considered for CBCT would normally have had the following interventions

a private dental consultation(s);

intra-oral radiographs; and/or

panoramic radiographs (OPG MBS item numbers 57959 - 57969) conducted by a suitably
qualified health professional such as a radiologist.
Page 7 of 29
Description of patient population
Dental implant planning (including management of suspected complications)
Dental implants are used to support dental restorations, such as prostheses, bridges and crowns, and
are a treatment option for patients with missing teeth (Hobkirk et al 2003). Teeth loss can occur
congenitally; due to dento-alveolar disease such as caries; teeth extraction for orthodontic treatment;
or dental trauma (Hobkirk et al 2003; Roberts-Thomson & Do 2007).
Dental implant treatment commonly involves two stages:
(i) dental implant surgery - inserting a titanium or titanium alloy into the jawbone to replace the
missing root of the teeth, and which then fuses (osseo-integrates) with the bone; and
(ii) restorative procedures - after the implant has healed, prostheses or teeth replacements such
as crowns and bridges may be inserted (Hobkirk et al 2003; Mitchell et al 2009).
These procedures however may also be performed in a single stage depending on the clinical
indication, with the provision of a temporary crown initially, and a permanent prosthesis upon
satisfactory bone healing and osseo-integration of the implant.
For patients with missing teeth for whom dental implants are the selected treatment option, CT or
CBCT may be used to assist in pre-operative implant planning to assess the suitability of an implant
site (sufficient height, density and width of bone), locate anatomy to avoid when placing the implant
and determine the number, size and orientation of implants for optimal restorative results (White et al
2001).
To assess structures at risk of damage during planned surgery
Planned surgery includes removal of impacted teeth or wisdom teeth as well as other indications such
as treatment of cleft palate. Dental impaction however, is one of the most common applications of
CBCT. While most permanent teeth erupt into occlusion unassisted, some permanent teeth fail to
erupt in the appropriate site in the dental arch. Third molars are the most frequently impacted teeth,
followed by the permanent maxillary canines. In patients where the anatomy of the third molar is not
extremely abnormal and the tooth not correlated with the mandibular canal, surgery is not considered
hazardous and further assessment is not needed. In patients with concerns in the lower third molar in
which there is a relationship between the roots and the mandibular canal, a careful preoperative
evaluation is needed. In such cases, CT or CBCT provides valuable information in addition to
conventional radiographic techniques, potentially changing treatment to less invasive surgical
intervention leading to fewer complications. Scope of surgical planning may also include apical
surgery due to recurrent endodontic infection, root resection, periodontal surgery, bone grafts,
surgery to remove bony or dental pathology.
Assessment of the dentition and associated dento-alveolar, sinus and TMJ
For some patients, clinical assessment indicates there is an underlying pathology, but radiographs do
not provide information of relevance to patient management. This may be the case with indications
such as periodontal disease, dental inflammatory pathology associated with a non-vital tooth,
Page 8 of 29
anomalies of root anatomy and morphology, root resorption (internal and external), fractures,
dislocations, ankylosis, disc displacement; inflammatory diseases leading to synovitis and capsulitis;
arthritides; advanced degenerative disease; joint remodelling after diskectomy; and suspected disk
displacement (Miracle & Mukherji 2009; White et al 2001). Due to cost and radiation dose, CT and
CBCT may only be indicated for the diagnosis of conditions with complex bony abnormalities such as
ankylosis, complex fractures and bony pathoses; if hard and soft tissue evaluation is required, as in
the case of suspected disc displacement, Magnetic Resonance Imaging (MRI) is often the current
method of choice (Brooks et al 1997).
Listing proposed and options for MSAC consideration
Proposed MBS listing
Initially DMDI had requested that CBCT be listed on the MBS under four categories (see Appendix 1).
PASC agreed at its April 2012 meeting that one item descriptor should be developed for CBCT and
this would cover the clinical questions intended for assessment as part of this review. This is
consistent with the TGA listing that notes that CBCT is approved for dental and medical diagnostic
imaging (as opposed to specific indications within this category).
As part of consultation PASC invited comment on whether the proposed MBS descriptor should
included reference to the type of CBCT machine that would be eligible for reimbursement of CBCT
items. It has assumed that the designated 3D CBCT machines would be eligible; however PASC notes
that there are other machines, often referred to as hybrid machines, which can be used to
undertaken CBCT. Following consultation PASC determined at its August 2012 meeting that the
proposed item should cover CBCT or hybrid machines provided they meet accredited performance
characteristics consistent with a dedicated CBCT (see Appendix B).
PASC also agreed that the item descriptor be a radiologist referred item and to leave the current
ability for dentists (as well as specialist dentists) to refer for CBCT.
Table 3 outlines the revised wording for the proposed MBS CBCT item.
Table 3 PASC determined MBS item descriptor for CBCT
Page 9 of 29
Clinical place for proposed intervention
CBCT is being proposed in addition to clinical assessment with or without two dimensional imaging
(e.g. panoramic imaging) and as a replacement to CT.
CBCT offers more accurate and detailed imaging over that of 2D imaging. Patients however would be
exposed to higher radiation doses than under clinical assessment or 2D imaging alone.
As a replacement for CT, CBCT would function as a direct substitute for currently subsidised CT and
be used when lower dose conventional dental radiology cannot resolve the clinical questions. The key
clinical claim associated with CBCT relative to CT is that it has superior safety and (at least)
comparable effectiveness. As such, the expected impact of the introduction of CBCT on downstream
and upstream parts of the management algorithm would be minimal.
The above scenarios and below flowcharts are consistent with the principles outlined by SEDENTEXT
for the use of CBCT in dental practice http://www.sedentexct.eu/content/basic-principles-use-dentalcone-beam-ct.
Page 10 of 29
Figure 1 Management algorithm for planning of dental implants
Figure 2 Management algorithm for the assessment of patients with suspected dental implant complications
Page 12 of 29
Figure 3
Management algorithm for the assessment of patients undergoing planned dento-alveolar surgery
with a risk of injury (as diagnosed on prior imaging)
Page 13 of 29
Figure 4 Management algorithm for the assessment of patients with suspected dento-alveolar, temporomandibular
joint pathology which may not have been adequately assessed using two-dimensional radiographic
techniques.
Page 14 of 29
Comparator
CT has been used for dental and craniofacial imaging since its inception (White 2008). Multi detector
CT uses a x-ray source that rotates around the patient while 16 to 64 detector rows acquire
numerous thin ‘slices’, based on x-ray attenuation data, which are then stacked to construct images
in numerous formats and planes, including 3D images (Boeddinghaus & Whyte 2008; Sukovic 2003).
CT involves collimated fan shaped beams which take multiple thin slices in contrast to the single 3D
cone shaped beam used in CBCT (Scarfe et al 2006). CT provides excellent bony detail but can also
be used to assess craniofacial soft tissues (Boeddinghaus & Whyte 2008). CT equipment is large,
expensive, and involves exposure to ionising radiation.
CBCT is proposed to be used in addition to clinical assessment with 2D imaging. This may be two
dimensional imaging such as intra-oral radiographs or panoramic radiographs (OPG). Intra-oral
radiographs are one of the most common forms of radiographic techniques used in dental practice to
provide a 2D image of the teeth and jaws. Panoramic radiographs (OPG) are also used frequently.
OPGs involve low radiation exposure where an x-ray tube or film rotates about the patient’s head and
produces a flat image of the curved jaw surfaces (Boeddinghaus & Whyte 2006). The quality of
images however is variable as it may be influenced by patient positioning or movement of the patient,
which can lead to magnification, distortion, superimposition of shadows and image artefacts
(Boeddinghaus & Whyte 2006; Monsour & Dudhia 2008)..
Clinical claim
The clinical claims for CBCT relative to its comparator(s) (2D imaging and CT) are listed below.
Relative to 2D imaging, CBCT has the following potential benefits:


Superior visualisation by providing images that are 3D and which have:
‐
high spatial resolution;
‐
1:1 ratio requiring no magnification; and
‐
reduced image artifacts.
Improved accuracy of diagnosis and assessment:
Page 15 of 29
‐
improve understanding of the anatomical site, nature and mechanism of pathology
which may improve the ability to predict treatment success and select treatment, and
thereby improve patient health outcomes; and
‐
improve planning for therapeutic procedures for dental implants (due to improved
knowledge of the anatomical site and mechanism of pathology), which may lower
complication rates for procedures and devices and re-intervention rates due to failed
surgery or therapeutic devices.
Relative to 2D imaging, CBCT has the following potential harms:

substantially higher radiation dose.

limited ability to accurately diagnose dental caries, especially around or adjacent to preexisting restorations, especially metallic restorations
On the basis of the potential benefits and harms listed above, the key clinical claim associated with
CBCT relative to 2D imaging is that it has superior effectiveness (benefit of 3D imaging) but is done
at the cost of reduced safety.
Relative to CT, CBCT has the following potential benefits:

Exposes patients to lower radiation dependent on the type of machine used per use while
providing at least equal (or nearly equal) image quality.

Similar accuracy of diagnosis and assessment

Equal or superior images of the bony pathology of the oral and facial structures:
‐ high spatial resolution;
‐ 1:1 ration requiring no magnification; and
‐ reduced image artifacts.

Offer improved patient comfort:
‐
less claustrophobic;
‐
patient can be seated; and
‐
operator friendly.

Be conducted through a less expensive and smaller machine.
Relative to CT, CBCT has the following potential harms:



poor contrast resolution of soft tissue;
risk of repeat use due to use of multiple low field of view images for different regions;
collimation of beam is too narrow, and hence pathology is missed.
On the basis of the potential benefits and harms listed above, the key clinical claim associated with
CBCT relative to CT is that it has superior safety and (at least) comparable effectiveness to CT (i.e
minimal/no change in management).
Given the above a cost-effective analysis (CEA) or a cost-utility analysis (CUA) is the preferred model.
This however is dependent on the evidence; other approaches may be considered once the evidence
has been reviewed however these would need to be justified in the assessment report.
Page 16 of 29
Comparative safety
versus comparator
Table 4 Classification of an intervention for determination of economic evaluation to be presented
Comparative effectiveness versus comparator
Superior
Non-inferior
Inferior
Net clinical benefit CEA/CUA
Neutral benefit
CEA/CUA*
Superior
CEA/CUA
CEA/CUA
Net harms
None^
Non-inferior
CEA/CUA
CEA/CUA*
None^
CEA/CUA
Net clinical benefit
None^
None^
CEA/CUA*
Neutral benefit
Net harms
None^
Abbreviations: CEA = cost-effectiveness analysis; CUA = cost-utility analysis
* May be reduced to cost-minimisation analysis. Cost-minimisation analysis should only be presented when the proposed
service has been indisputably demonstrated to be no worse than its main comparator(s) in terms of both effectiveness
and safety, so the difference between the service and the appropriate comparator can be reduced to a comparison of
costs. In most cases, there will be some uncertainty around such a conclusion (i.e., the conclusion is often not
indisputable). Therefore, when an assessment concludes that an intervention was no worse than a comparator, an
assessment of the uncertainty around this conclusion should be provided by presentation of cost-effectiveness and/or
cost-utility analyses.
^ No economic evaluation needs to be presented; MSAC is unlikely to recommend government subsidy of this intervention
Inferior
The key uncertainties surrounding the selection and implementation of the economic analysis include
the following:

Obtaining comparative effectiveness data to populate a CEA/CUA model. As CBCT is a
relatively recent technology, there is likely to be limited evidence relating to its comparative
effectiveness and much of the data may be in the form of case series or more technical papers
rather in the context of a clinical study. To date, much of what has been published compares
CBCT to OPG (replacement and incremental) rather than CBCT as a replacement to CT.

Obtaining accurate safety data for the CEA/CUA. The lower radiation dose of CBCT relative
to CT, and hence its superior safety, is one of the key clinical claims of CBCT. The safety
assessment should (i) justify the use of the chosen indicator of radiation dosimetry, (ii) account
for variations in radiation exposure that will occur based on the model of CBCT used and the field
of view and (iii) account for utilisation factors which may influence lifetime radiation exposure and
cost (see below).

Estimating the utilisation of CBCT. Factors pertaining to the setting in which CBCT is used
and its mode of operation which may influence its utilisation and hence its cost. For example:
o
whether the use of limited field of view CBCT encourages repeat usages, despite having
a lower radiation exposure per dose.
Page 17 of 29
Outcomes and health care resources
introduction of proposed intervention
affected
by
Outcomes
The outcomes to be considered in the proposed assessment of CBCT versus its comparators (are
listed below:
Planning of dental implants
Management of dental implants
Safety
Safety
Radiation dose
Radiation dose
Adverse events
Adverse events
Diagnostic accuracy
Diagnostic accuracy
Sensitivity
Sensitivity
Specificity
Specificity
Additional TP & FP
Additional TP & FP
Change of Management
Change of Management
Re-implantation/revision surgery
Re-implantation
Heath Outcomes
Heath Outcomes
Osseointegration
Osseointegration
tooth survival/restoration
tooth survival/restoration
quality of life
Surgical morbidity
Dental function
Quality of life
Assessment of patients undergoing planned dento-alveolar surgery
with an increased risk of injury
Safety
Radiation dose
Adverse evens
Diagnostic accuracy
Sensitivity
Specificity
Additional TP & FP
Change of management:
% of treatment plans changed
Surgical procedures avoided
Health outcomes Surgical
morbidity Avoidance of
nerve injury
Avoidance of sinus perforation
Alleviation of pain
Periodontal healing
Dental function
Quality of life
Assessment of patients with suspected TMJ or dento-alveolar pathology
Safety
Radiation dose
Adverse events associated with subsequent surgery or treatment
Diagnostic accuracy
Sensitivity
Specificity
Additional TP & FP
ROC
Change of management:
% of treatment plans changed
Surgical procedures avoided
Health outcomes Restored
jaw function Alleviation of
oro-facial pain Quality of life
Health care resources
Expected impact of the introduction of CBCT on the use of associated interventions
The use of CBCT in patients who previously would have undergone 2D imaging alone will result in an
increase in costs in the diagnostic phase of the indications, however, if CBCT enables more effective
diagnosis and assessment then this may be offset by a reduction of costs associated with the
treatment and management of adverse effects and re-intervention following failed treatment.
As a replacement to CT; prior diagnostic imaging and consultations leading up to the use of CBCT and
dental procedures performed after CBCT are likely to remain the same after the introduction of CBCT,
but may be done more safely (with less radiation exposure). However, as above, if CBCT enables
more effective diagnosis and assessment relative to its comparators, then this may lead to a
reduction of adverse effects and re-intervention following failed treatment and a change in the
utilisation of the health care resources used to treat or manage these complications.
Page 19 of29
Table 5: List of resources to potentially be considered in the economic analysis (not exhaustive list)
Page 19 of29
Proposed structure of economic evaluation
The following questions are being proposed:

to assess bone quantity and quality as part of dental implant planning and in management of
suspected implant complications;

to assess structures identified clinically or on 2D radiographs as being in close approximation
to sites of planned dento-alveolar surgery that may be at risk of damage during surgery; and

further assessment of the dentition and associated dento-alveolar and TMJ pathology which
may not have been adequately assessed using two-dimensional radiographic techniques.
Assessment of bone quantity and quality as part of dental implant planning and
in management of potential implant complications.
In this scenario it is proposed that the main benefits of CBCT as an addition to clinical assessment
with or without 2D imaging will be a reduction in complications through the provision of more
accurate/detailed imaging in regards to bone quantity and quality leading to better osseointegration
and patient outcomes but with an increase exposure to radiation. As a replacement for CT, patient
outcomes should be similar but with a reduction in radiation exposure.
Table 6 PICO to define the research question for the assessment of bone quantity and quality as part of dental
implant planning.
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Table 7 PICO to define the research question for the assessment of bone quantity and quality as part of the
management of suspected implant complications.
Page 21 of29
Assessment of structures identified clinically or on 2D radiographs as being in
close approximation to sites of planned dento-alveolar surgery that may be at
risk of damage during surgery
In this scenario, it is proposed that the main benefit of CBCT as an addition to clinical assessment
with or without 2D imaging will be a reduction in surgical morbidity (e.g. avoidance of nerve injury)
through the provision of more accurate/detailed imaging but with an increase exposure to radiation.
As a replacement for CT patient outcomes should be similar but with a reduction in radiation
exposure.
Table 8 PICO to define the research question for the assessment of patients undergoing planned dento-alveolar
surgery with an increase risk of injury as diagnosed on prior imaging
Page 22 of29
Assessment
of
the
dentition
and
associated
dento-alveolar
and
temporomandibular joint pathology which may not have been adequately
assessed using 2D radiographic techniques.
In this scenario, it is proposed that the main benefit of CBCT as an addition to clinical assessment
with or without 2D imaging will be a more accurate diagnosis (e.g. avoidance of unnecessary
treatment) through the provision of more detailed imaging but with an increase exposure to radiation.
As a replacement to CT it is assumed that outcomes should be similar but with a benefit of reduced
radiation exposure for those undergoing CBCT.
Table 9 PICO to define the research question for the assessment of the dentition and associated dento-alveolar, or
temporomandibular joint pathology which may not have been adequately assessed using two-dimensional
radiographic techniques.
Page 23 of29
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17.
White, SC, Heslop, EW et al 2001. Parameters of radiologic care: An official report of the
American Academy of Oral and Maxillofacial Radiology, Oral Surgery Oral Medicine Oral
Pathology Oral Radiology & Endodontics, 91 (5), 498-511.
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Appendix A
Background information on item descriptor
DMDI had requested that CBCT be listed on the MBS under the proposed categories as shown in
Table 10. Two additional categories were proposed by DIMI; one for temporal and skull base/ENT
and another for sleep apnoea. These are not included here as it was agreed at the April PASC
meeting that these indications are not being reviewed as part of this assessment.
DMDI have proposed that CBCT items be classified under Category 5 – Diagnostic imaging services:
Group I2 – Computed Tomography under a new sub heading entitled ‘Cone Beam CT’. The fee
proposed for each item is based on the sum of a combination of multiple x-ray codes (the practice
undertaken prior to the introduction of the CBCT interim item) i.e. Dentomaxillofacial Imaging is
proposed at $288.15 which is a combination of 57912, 57915, 57933, 60100 and 57901; Head and
Neck is proposed at $336.80 (57903+57906+56022). Both proposed fees are more than the current
MBS rebate for CBCT and more than the rebate offered for CT of facial bones (MBS 56022 $225.00).
Further information will be needed to justify the higher fee.
Table 10:Proposed MBS item descriptor for CBCT – Option 1
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Appendix B
RANZCR advice on minimum equipment requirements for CBCT machines
(Submitted as part of consultation and presented at August PASC)
RANCR recommendations that hybrid machines should be eligible Medicare rebates on the condition
that their spatial resolution, tube focal spots and radiation exposure figures are at least equivalent to
a dedicated 3D Cone Beam machine based on the following specifications:
1. The acquisition should be obtained with the patient sitting and with an appropriate immobilisation
device for the chin.
2. The acquisition time should be variable depending on quality of scan required:
-
The acquisition time should be a maximum of 40 seconds for a high resolution scan;
-
This scan time should be able to be reduced to 10 seconds or less when a lower
resolution, but still diagnostic scan is required (e.g. for paediatric patients).
3. The FOV needs to be variable to minimize radiation exposure. The imaging field of view should
collimate down to at least 6cm and be adjustable with increments of 2cm or less, and the maximum
field of view should be 17cm in order to negate the need for another exposure for a Lateral
Cephalogram.
4. The detector needs to be a flat panel device.
5. As a base line, the maximum effective dose for both Jaws should be less than or equal to 100
microSv using the 2007 ICRP weighting factors.
6. A maximum tube current of 12mA.
7. Ability to achieve a nominal focal spot size of 0.6mm or less.
8. Ability to achieve a minimum voxel volume of no greater than 0.25mm x 0.25mm x
0.25mm at the isocentre.
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Appendix C
Decision trees relating to the clinical questions
Please note that the following decision trees given here are provided for the purposes of
supplementing the information given in the PICO tables and clinical algorithms and may not reflect
the cost-effectiveness models required in the final assessment
Figure 5 Simplified decision tree structure for the assessment of bone quantity and quality as part of dental implant
planning and in the management of suspected implant complications
Figure 6 Simplified decision tree structure for the assessment of patients undergoing planned surgery with an
increase risk of injury as diagnosed on prior imaging
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Figure 7 Simplified decision tree structure for the assessment of the dentition and associated dento-alveolar or
temporomandibular joint pathology which has not been adequately assessed using two-dimensional radiographic
techniques.
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