Adult and pediatric cone-beam computed tomography dosimetries

We read the article of Dr Najjar et al comparing adult and pediatric cone-beam computed tomography (CBCT) dosimetries (Najjar A, Colosi D, Dauer L, Prins R, Patchell G, Branets I, et al. Comparison of adult and child radiation equivalent doses from 2 dental cone-beam computed tomography units. Am J Orthod Dentofacial Orthop 2013;143:784-92) with great interest but were disappointed to discover that the parameters used didn’t reflect reality. For example, the pediatric phantom used was for a 5-year-old boy, even though the American Association of Orthodontists doesn’t recommend an initial examination until age 7. A more realistic and relevant phantom would have been either the male or female 10-year-old phantom currently offered by Computerized Reference Imaging Systems (Norfolk, Va). The choice of the younger, and more radiosensitive, phantom unfortunately diluted the power of the study, since it’s rare to see a 5-year-old patient for an orthodontic examination and even more rare to capture any orthodontic diagnostic radiographic records, either 2-dimensional or 3-dimensional, of a 5-year-old.

We’re also concerned that the 4.8-second scan, which was also available on the i-CAT model tested, wasn’t evaluated in addition to the scans of 8.9 and 26.9 seconds. The 26.9-second scan is rarely, if ever, used clinically for orthodontic diagnostic purposes, since it greatly increases the odds that motion artifacts will be introduced into the scan. For that reason, the scans of 4.8 and 8.9 seconds are used most often as diagnostic scans. Although the i-CAT might not have a labeled pediatric setting, the 4.8-second scan is clinically used for that purpose, and its omission unfortunately undermines the clinical relevancy of the research.

Finally, we found it worrisome that the authors began to editorialize in the conclusions. The conclusion reaches beyond the findings of the study to share the opinion that CBCT “should not be used for routine diagnosis.” It is not our goal to offer any commentary on the validity of the statement regarding the routine use of CBCT except to point out that the research was not designed to answer that question; therefore, its inclusion in the conclusions is inappropriate. Although we applaud the authors for their efforts to add to the knowledge base regarding CBCT dosimetry, we unfortunately feel that the flaws inherent in this article undermine its credibility and clinical relevance.

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Apr 6, 2017 | Posted by in Orthodontics | Comments Off on Adult and pediatric cone-beam computed tomography dosimetries
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