Does the patient need a scan? This is determined from our assessment of the
referral reason from the dentist and from our clinical/medical history for the
patient. Typically, if the patient has one of the indications for a scan
that are listed on this page, a scan would be justified.
Is the patient pregnant?The horizontal trajectory of the CBCT beam
through the patient's jaw suggests that
the patient's foetus would not be subjected to any direct radiation, and that
the only exposure the foetus would receive would be from scattered radiation trough
the patient's torso (which would be minimal). Dosimetry studies with the Kodak 9000
CBCT have suggested that the effetive dose to a patient's reproductive organs is
negligible. Therefore, pregnancy is not considered a
contraindication
to a CBCT scan. However, in the rare instances where scanning of a pregnant patient
comes up, we should offer the patient the opportunity to postpone the procedure.
Is the patient a child?Children are more radiosensitive, so
Canaray has instituted the following rules regarding CBCT scans for anyone younger than 17:
Use lower scanning parameters for kV and mA in proportion to the patient's
size. The smaller the patient, the lower the kV and mA settings should be
Do not take medium or large scans of children unless a significnant surgery
is planned (e.g. Cleft lip/palate, orthognathic, tumor removal)
Attempt to fit impacted maxillary canines into the smallest scan field possible
Accept lower quality scans as they pertain to clarity and patient movement. Do not
repeat scans due to poor quality unless the image is non-diagnostic.
If it is apparent that the patient will not be able to remain motionless
for the duration of the scan, consider declining imaging. One criterion for
a CBCT scan is a motionless patient
Order of Operations
In order to ensure that we're doing the right thing, we need to follow the following order of operations for every patient. Do not skip any step or
do any step in the incorrect order:
Patient Check-in Every patient should walk in with a referral form. The front desk checks in every patient.
If any information on the referral form is missing, contact the referring dental office to fill in the blanks. If the patient
walks in without a referral form, get the refering dental office to fax us a form or make an online referral.
Medical History During the medical history, confirm the patient's referral information and the correctness
of their personal information. Ask the medical history questions that are pertinent to the type of case it is (e.g.
TMJ, implants, impacted teeth, etc). Determine whether a scan is warranted or not. Always choose the smallest scan that will
adequately capture the region of interest. Get confirmation from the Oral Radiologist
Get consent Print out the consent form and go over the following specific items:
Correct patient name and telephone number
Reason for referral (use layperson terms like "lower left" and "all your top teeth" to make sure the patient agrees with the
referral reason that is written down by the referring dentist)
List the recipients of the data/report. The patient must know who will have access to their data.
Our suggested imaging and the cost
The type and amount of radiation we expect to be imparted, and a comparison to radiation levels from familiar
items, such as Pans, intraorals, days of background radiation, medical CT, etc.)
Our privacy policy
Give the patient an opportunity for questions and clarification or to decline imaging at Canaray
Receive signed informed consent. Never perform any imaging at Canaray without a signed consent form. If anyone refuses to
provide written consent, we must refuse imaging.
Photos If any soft tissue lumps or bumps or discolorations are present, take a photo or two. It helps with
the diagnosis.
Perform imaging Support staff may set up the patient in the scanner. The actual position confirmation and
acquisition must be done by the Medical Radiation Technologist, or the Oral Radiologist if the MRT is not available.
Image quality assessment Prior to dismissing any patient, the scan quality must be assessed. If
the region of interest is incompletely captured, or unacceptable movement artifacts are present, get the Oral Radiologist's
opinion on whether or not the scan should be repeated or whether additional plain films are necessary.
Payment Collect payment from the patient and provide prefilled insurance claim forms. Do not commence
reporting or processing on any case that is not fully paid for.
Dismissal After the image quality has been satisfactorily assessed, the patient may be dismissed.
Radiation shielding for patients
All patients must wear a panoramic cape in the Kodak 9000
All patents must wear a scanning poncho in the Kodak 9500.
Please ensure that the poncho does not ride up the patient's neck. If
the superior border of the poncho is positioned at a higher level than the inferior border
of the mandibular symphysis, image quality will be reduced.
Thyroid collar A thyroid collar should be worn whenever possible.
A problem with thyroid collars is that they tend to be seated higher on the posterior
neck, which results in an artifact in the mandibular region during imaging. Therefore,
a thyroid collar should be used for every scan of the maxillary arch.
Specific
situations for mandibular scans in which a thyroid collar do not need to be worn are:
Patient with a short neck (e.g. heavy-set patients)
Patients with a hunched back
Situations where the presence of the collar prevents correct patient positioning for
image capture.
Radiation shielding for staff
Stand outside the room with the door closed Every scan must be performed from outside
the lead-walled scanning room with the thick glass sliding door closed. There are no exceptions to this rule.
Scan acquisition by authorized personnel
Oral radiologist or Medical Radiation Technologist only Only the oral radiologist
or the medical radiation technologist on duty is permitted to perform the actual acquisition of the
CBCT scan. The remainder of the tasks may be delegated to other staff members.
When in doubt, ask the oral radiologist
The ultimate responsibility for the patient's care lies with the oral radiologist on duty.
If you're not sure about something, ask the radiologist. It's much better to ask before we do the imaging
and before the patient leaves.
Report and document all errors
Errors are insiduous and may become systematic if we don't document them and take precautions to prevent
them in the future
Use the problem tracker If you recognize an area of our operation that
is error-prone or requires improvement, document it on the problem tracker. If you have a potential
solution to the problem, suggest it on the problem tracker.
DO NOT HIDE YOUR ERRORS If you have done something wrong, it's best to
let the rest of us know so that we can remedy the problem proactively and then think about
how to prevent the same sort of error in the future.
Recognize that most of our errors can be traced to the critical first 15 minutes of the patient's appointment
This is the time where we are gathering information about patients and their needs, and sets the stage for all the work that
is to follow. If the quality of this data collection is poor, our execution will be poor because we are basing our work on
potentially inaccurate information. We must strive to ensure that the patient information is as accurate as possible. Double and triple
check your work at this stage, because once a patient's name is entered incorrectly, for example, it shows up that way in every DICOM slice
and every document that we produce from then onwards.
1. Endodontics & Root Resorption
Indications
Troublesome teeth (endodontic pathology)
Endodontic retreatments
Root perforations
Internal and external root resorption
Detecting secondary signs of root fracture
Periapical pathology
Contraindications
Root fractures: CBCT cannot reliably detect non-displaced root fractures. Only
secondary signs of fracture (such as a widened periodontal ligament space adjacent
to the fracture plane) can be visualized.
Metallic posts: Highly radiopaque objects such as metallic posts and dense
endodontic fillings cause severe beam hardening artifacts in the roots of the
affected tooth. These artifacts can be misdiagnosed as fractures.
Scanning notes
The tooth should be centered in the scan. The crown and root tip should be fully imaged
Patient movement is particularly critical in these scans. The scan should be repeated if
the patient moves and blurs the image
If pathology is associated with this tooth, make sure it is completely captured in the scan. If
the pathology is not fully captured, repeat the scan at the same size in a different position, or take a larger scan
For multiple endodontic scans in multiple quadrants, take multiple small field scans. Never
take a large field low-resolution scan. High resolution is of utmost importance for this type
of scan
Scanner settings
Scanner
Kodak 9000
Field size
4x5cm
Voxel size
100um (0.1mm)
Adult Anterior
70kV/10mA
Adult Posterior
90kV/10mA
Child Anterior
65kV/8mA
Child Posterior
80kV/8mA
Scanner
Scanora
Field size
60x60mm HIGH RESOLUTION
L/R Alignment
Align with region of interest
A/P Alignment
Left edge of scout cuts of 1/2 of ROI
Adult
90kV/12mA
Child
90kV/8mA
2. Impacted teeth
Indications
Supernumerary teeth
Impacted maxillary canines
Wisdom teeth
Any other unusually positioned tooth
Contraindications
No contraindications for imaging of impacted teeth.
Scanning notes
The majority of patients presenting with impacted teeth are children. Use
scanner settings that are appropriate for pediatric patients.
The tooth should be centered in the scan. The crown and root tip should be fully imaged
Patient movement is particularly critical in these scans. The scan should be repeated if
the patient moves and blurs the image
If pathology is associated with this tooth, make sure it is completely captured in the scan. If
the pathology is not fully captured, repeat the scan at the same size in a different position, or take a larger scan
For impacted teeth in up to 2 quadrants, take multiple small field scans. For 3 or more
quadrants, use the large field scanner
Scanner settings
Scanner
Kodak 9000 (1-2 quadrants)
Field size
4x5cm
Voxel size
100um (0.1mm)
Adult Anterior
70kV/10mA
Adult Posterior
90kV/10mA
Child Anterior
65kV/8mA
Child Posterior
80kV/8mA
Scanner
Kodak 9500 (3-4 quadrants)
Field size
11x17cm
Voxel size
200um (0.2mm)
Adult
90kV/10mA
Child
80kV/8mA
Very young child
63kV/6.3mA
Scanner
Scanora (Teeth 13 and/or 23 + all patients younger than 10)
Field size
60x60mm High Resolution
L/R Alignment
Align with midline
A/P Alignment
Left edge of scout cuts of 1/2 of 13 and 23
Adult
90kV/12mA
Child
90kV/8mA
3. Pathology
Indications
Bone pathology
Any disease that has an effect on the bones of the jaws
Sinus pathology
Contraindications
Soft tissue pathology. CBCT scans are not useful for soft tissue structures such as tongues or lips or cheeks.
Scanning notes
Pathology encompasses a very broad spectrum of scanning protocols, because you could have
pathology anywhere. There are no specific rules for imaging pathologic entities, but some guidelines that
may be helpful are:
Capture the boundaries of the pathologic entity, if possible
Take a high resolution scan, if possible. Fine details are more important for assessing pathology than for certain other
imaging indications
If the pathology is at the anterior midline, and you are using the Kodak 9000 CBCT scanner, be sure to decrease the
beam intensity appropriately so that the thin cortices of the maxillary or mandibular alveolar process are
not overexposed.
During implant scanning, if the visible portion of the maxillary sinus is completely opacified in a small field scan, we should
make a larger field scan to fully visualize the sinus.
Scanner settings
Scanner
Kodak 9000 (small pathologic entities up to 2x3cm)
Field size
4x5cm
Voxel size
100um (0.1mm)
Adult Anterior
70kV/10mA
Adult Posterior
90kV/10mA
Child Anterior
65kV/8mA
Child Posterior
80kV/8mA
Scanner
Kodak 9500 (large or biliateral pathologic entities)
Field size
11x17cm
Voxel size
200um (0.2mm)
Adult
90kV/10mA
Child
80kV/8mA
Very young child
63kV/6.3mA
Scanner
Scanora (small pathologic entitities up to 3x3cm
Field size
60x60mm High Resolution
L/R Alignment
Align with region of interest
A/P Alignment
Left edge of scout cuts of 1/2 of ROI
Adult
90kV/12mA
Child
90kV/8mA
Scanner
Scanora (large or bilateral pathologic entities)
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of maxillary 1st molar
Adult
90kV/12mA
Child
90kV/8mA
4. Temporomandibular Joints
Indications
Suspected damage to osseous structures of TMJs
Contraindications
Evaluation of soft tissues of the TMJs, such as the articular discs. These are not visible
in CBCT.
Scanning notes
Some clinicians request many TMJ views at the same time (e.g. closed, open, protrusive, bite registration, etc). We must
remember that each view requires a complete scan, so we much do everything we can to minimize the overall dose
to the patient. Some techniques to provide the information requested while keeping doses low are:
Reduce the number of scans. Does the clinician really need protrusion and bite-registration positions?
Only take one high quality scanThe scan in the mandibular closed position should be a high-quality scan.
All remaining scans should be at low mA settings, because we are only interested in the position of the condylar heads
in these scans.
More scans = lower mA settingThe more scans you need to take, the lower the mA settings should be for the
scan. For example, if you need two scans, your second scan should be at 5.0mA. If you need 3 scans, your 2nd and 3rd scans
should be at 3.2mA
Limit scans in children and teens We should limit scans of children and teens to a single TMJ scan in
the mandibular closed position, if possible.
Prop mouth fully open in open position Do not rely on the patient to keep his/her mouth fully open
for the duration of the scan. Prop the mouth open at maximal opening with +/-20 tongue depressors between the anterior teeth. This will reduce
movement artifacts during the scan. Do not use a bite block. Bite blocks distort jaw positions.
Use the smallest scan that will fit the region of interest PLUS one tooth on either side.
For maxilla from 13 to 23, use the Koak 9000
For the mandible between the mental foramina in an edentulous patient, use the Kodak 9000. If the person's mandibular
midline is taller than 35mm from cusp tip to inferior border, do a medium field scan
In the mandibular molar region, make sure to capture enough height to see the entire mandibular nerve. It is not
necessary to see the inferior border of the mandible for mandibular molars
In the maxillary posterior region, if the portion of the sinus that is visible in the scan is completely opacified,
take a larger scan that adequately demonstrates the state of the sinus
Scanner settings
Scanner
Kodak 9000 (up to 3 contiguous teeth, or 13-23, or edentulous anterior mandible)
Field size
4x5cm
Voxel size
100um (0.1mm)
Adult Anterior
70kV/10mA
Adult Posterior
90kV/10mA
Child Anterior
65kV/8mA
Child Posterior
80kV/8mA
Scanner
Kodak 9500 (All other implant planning scansj)
Field size
11x17cm
Voxel size
200um (0.2mm)
Adult
90kV/10mA
Child
80kV/8mA
Very young child
63kV/6.3mA
Scanner
Scanora
Less than 1 Quadrant
3 continuous teeth or 13-23 or edentulous anterior mandible
Field size
60x60mm High Resolution
L/R Alignment
Align with region of interest
A/P Alignment
Left edge of scout cuts of 1/2 of ROI
Adult
90kV/12mA
Child
90kV/8mA
Scanner
Scanora
Maxilla
Quadrant 1 and/or Quadrant 2
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of maxillary 1st molar
S/I Alignment
Lower laser at CEJ of mandibular teeth
Adult
90kV/12mA
Child
90kV/8mA
Scanner
Scanora
Mandible
Quadrant 3 and/or Quadrant 4
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of mandibular 1st molar
S/I Alignment
Upper laser at CEJ of Maxillary teeth
Adult
90kV/12mA
Child
90kV/8mA
6. Simplant
Indications
Implant planning with the Simplant CAD/CAM guided surgery system
Contraindications
None
Scanning notes
The patient's teeth MUST be separated for these scans
In order to facilitate segmentation of the scan data, absence of
patient movement is of utmost importance. The quality criterion for a
Simplant scan is more rigorous when it comes to movement artifacts.
The entire arch of interest must be captured. Therefore, only medium field scans
should be made for this indication
Edentulous cases for mucosa-supported guides require scan markers to be affiaxed to the
plastic denture for the scan. Scan the denture alone as well. Note that the denture must
fit really well. If it does not fit well, it will need to be relined.
Scanner settings
Scanner
Kodak 9500 (Use 3D bite block to separate teeth)
Field size
11x17cm
Voxel size
300um (0.3mm)
Adult
90kV/10mA
Child
Not usually indicated
Scanner
Scanora
Maxilla
Quadrant 1 and/or Quadrant 2
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of maxillary 1st molar
S/I Alignment
Lower laser at CEJ of mandibular teeth
Adult
90kV/12mA
Child
90kV/8mA
Scanner
Scanora
Mandible
Quadrant 3 and/or Quadrant 4
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of mandibular 1st molar
S/I Alignment
Upper laser at CEJ of Maxillary teeth
Adult
90kV/12mA
Child
90kV/8mA
7. Nobelguide
Indications
Implant planning with the Nobelguide CAD/CAM guided surgery system
Contraindications
Any other brand of implants than Nobel
Scanning notes
The radiographic guide must be fabricated using a
specific lab protocol. The radiographic guide always has 6 to 8 pink
gutta percha dots on it in the gingival region.
All cases that will eventually be turned into actual surgical guides
require a radiographic guide. Some clinicians ask for "Nobelguide format"
even if a guide is not supplied, but make sure it says "No guide supplied"
on the referral form before doing a scan without a guide.
Patient movement must be minimized for this type of scan. The radiographic
guide markers must show up clearly.
If the patient has a silicone bite registration, make sure it is used to
stabilize the radiographic guide during the scan
All guides must also be scanned individually. Take a
separate scan of each pre- and post- surgical guide in the lab box. If you're
not sure, scan everything in the box that is made of acrylic.
Scanner settings
Scanner
Kodak 9500 (Use radiographic guide + bite registration to stabilize radiographic guide)
Field size
11x17cm
Voxel size
300um (0.3mm)
Adult
90kV/10mA
Child
Not usually indicated
Scanner
Scanora
Maxilla
Quadrant 1 and/or Quadrant 2
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of maxillary 1st molar
S/I Alignment
Lower laser at CEJ of mandibular teeth
Adult
90kV/12mA
Child
90kV/8mA
Scanner
Scanora
Mandible
Quadrant 3 and/or Quadrant 4
Field size
75x100mm High Resolution
L/R Alignment
Midline
A/P Alignment
Left edge of scout cuts of 1/2 of mandibular 1st molar