Several studies have been performed that include dosimetry of CBCT equipment. The literature review conducted by the SEDENTEXCT project and published in the Provisional Guidelines document 11 studies in which dosimetry for CBCT was performed and in which effective dose was calculated using tissue weighting factors taken from ICRP (2007). included

Table 1 shows the reported effective doses for a range of dental CBCT units along with comparative data for conventional imaging techniques. Table 2 presents the effective dose for conventional imaging and conventional multi-slice CT (MSCT) imaging. The majority of studies were based on thermoluminescent (TLD) dosimetry techniques using anthropomorphic phantoms. They showed significant variation in methodology, especially with respect to the type of phantom used and TLD number and positioning. The effect of the number and position of the TLD dosimeters on the accuracy of the assessment has not been assessed

Life is a risky business. Among the many risks to which we are prone, we are all constantly exposed to normal background radiation, which averages about 2400 µSv (European Commission, 2001) each year (average world figures). Medical exposures (of which dental radiology contributes a small fraction) add substantially to this figure, with wide variation from country to country. With this in mind, a panoramic radiograph may be associated with an effective dose the same as 1-5 days’ additional background radiation, while the dental CBCT risk could result in an effective dose equivalent to a few days up to a couple of months of background radiation, depending on the type of the machine and clinical protocol used.

Exposure to ionising radiation is associated with risks of various types. In diagnostic radiology, in particular with the low doses seen in dental and maxillofacial radiology, the radiation risk is of a very small increase in risk of cancer. Table 1: The range of effective dose from dental CBCT in mSv. Studies are divided into those in which “dento-alveolar” CBCT (fields of view smaller than the facial region) and “craniofacial” CBCT, in which the field of view routinely includes at least the maxilla and mandible.

Dental CBCT unit Effective References
  Dento-alveolar Craniofacial Dento-alveolar Craniofacial
NewTom 41-75 30-78 Ludlow et al 2003 Ludlow et al 2006 Okano et al 2009
Silva et al 2008
Ludlow et al 2003
Ludlow et al 2008
Mah et al 2003
Tsiklakis et al 2005
Accuitomo/ Veraviewepocs 11-102   Okano et al 2009
Loftag-Hansen et al 2008
Hirsch et al 2008
Loubele et al 2008
 
Galileos   70-128   Ludlow et al 2008
Promax 488-652   Ludlow et al 2008  
Prexion 189-388   Ludlow et al 2008  
i-CAT 34-89 48-206 Roberts et al 2009
Loubele et al 2008
Ludlow et al 2006
Roberts et al 2009
Loubele et al 2008
Ludlow et al 2008
Mah et al 2003
CB MercuRay 407 283-1073 Ludlow et al 2008 Ludlow et al 2006
Okano et al 2009
Ludlow et al 2008
Illuma   98-498   Ludlow et al 2008

Table 2: Effective dose from conventional dental imaging techniques in mSv

  Effective dose (μSv) References
Intra-oral radiograph <8.3* European Commission 2004*
Panoramic radiograph 2.7 - 23 Ludlow et al 2006
Okano et al 2009
Silva et al 2008
Palomo et al 2008
Garcia-Silva et al 2008
CT maxillo-mandibular 180 - 2100 Ludlow et al 2006
Okano et al 2009
Silva et al 2008
Loubele et al 2005
CT maxilla 1400 Ludlow et al 2006

*no data available calculated subsequent to ICRP2007

 

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