CBCT uses a fraction of the dose of a hospital CT scan.

CBCT radiation basics

Cone beam computed tomography (CBCT) uses ionizing X-ray radiation to produce three-dimensional volumetric images of dental and craniofacial structures. Like all medical X-ray modalities, CBCT involves a defined radiation exposure that is weighed against the clinical benefit of obtaining the image.

CBCT is distinct from conventional medical computed tomography (MDCT or “hospital CT”). Medical CT scanners rotate fully around the patient and use significantly higher radiation doses. CBCT uses a cone-shaped X-ray beam and a flat-panel detector to capture the entire volume in a single rotation, which allows for substantially lower dose while maintaining clinically useful resolution for dental and maxillofacial applications.

CBCT dose is also generally higher than a single panoramic (OPG) radiograph, but provides three-dimensional data that a panoramic image cannot. The clinical value of the additional information is assessed by the prescribing dentist or physician.

The ALARA principle

All radiation use in MyNavi Scan operations is governed by the ALARA principle: As Low As Reasonably Achievable. This is the standard framework used in dental and medical radiography worldwide.

In practice, ALARA means our technologist selects the smallest field of view appropriate for the clinical request, uses the lowest dose protocol that will produce a diagnostically useful image, and does not repeat scans unless clinically necessary. Lead aprons and thyroid collars are available for patient use when appropriate.

Typical effective dose ranges

The table below provides approximate effective dose ranges for common dental and medical imaging modalities. All values are estimates from published literature and professional guidelines. Actual dose received during any specific scan depends on the equipment, protocol, FOV, and patient anatomy.

All values are approximate ranges from published literature. Actual dose may vary depending on scan mode, FOV, and clinical protocol. These figures are provided for general educational comparison and should not be used as precise clinical dose estimates.

How FOV and protocol affect dose

The two primary variables controlling CBCT dose are field of view (FOV) and the imaging protocol (resolution, rotation arc, and tube settings).

• Small FOV (e.g., 5 x 5 cm): Limits the irradiated volume to a localized area. Used for endodontic assessment. Produces the lowest effective dose among CBCT modes.
• Large FOV (e.g., 15 x 16 cm): Captures the full craniofacial volume for airway, sinus, or pathology assessment. Irradiates a larger area; dose is correspondingly higher.
• Low-dose protocols: The PreXion3D Explorer EX supports dose-reduction scanning modes. The technologist selects the appropriate protocol based on the clinical request and ALARA principles.

The prescribing clinician's clinical request determines the minimum FOV necessary. Our technologist does not select a larger FOV than the prescription requires.

Low-dose protocols

The PreXion3D Explorer EX includes dedicated dose-reduction imaging modes. These modes reduce tube current, rotation arc, or resolution settings to lower patient dose while maintaining sufficient image quality for the intended clinical use.

Protocol selection is made by the ARRT-certified technologist based on the clinical request provided by the referring dentist or physician. When a low-dose protocol is clinically appropriate, it is used by default.

Prescription requirement

CBCT scans performed by MyNavi Scan require a written prescription from a licensed dentist or physician. This requirement exists under the Illinois Dental Practice Act and standard radiographic imaging guidelines.

MyNavi Scan does not self-prescribe scans, does not independently initiate imaging without a valid prescription, and does not provide clinical interpretation or diagnosis of CBCT images. Interpretation of images for clinical purposes is the sole responsibility of the referring clinician.

Pregnancy policy

CBCT scans are not performedon patients who are pregnant or who may be pregnant. All patients of childbearing age are asked about pregnancy status prior to any scan. If there is any uncertainty, the scan is not performed without prior clearance from the patient's physician.

This policy applies without exception and aligns with standard radiographic safety guidelines for pregnant patients.

Reference guidelines

Our safety protocols are informed by published position statements from the American Dental Association (ADA) and the American Academy of Oral and Maxillofacial Radiology (AAOMR) on the use of cone beam CT in dental practice. We recommend that clinicians and patients consult those official guidelines directly for detailed clinical recommendations.

• ADA: ada.org — search “cone beam CT guidance”
• AAOMR: aaomr.org — position papers on CBCT use and dosimetry