Assessment of phantom dosimetry and image quality of i-CAT FLX cone-beam computed tomography.

INTRODUCTION The increasing use of cone-beam computed tomography in orthodontics has been coupled with heightened concern about the long-term risks of x-ray exposure in orthodontic populations. An industry response to this has been to offer low-exposure alternative scanning options in newer cone-beam computed tomography models. METHODS Effective doses resulting from various combinations of field of view size and field location comparing child and adult anthropomorphic phantoms with the recently introduced i-CAT FLX cone-beam computed tomography unit (Imaging Sciences, Hatfield, Pa) were measured with optical stimulated dosimetry using previously validated protocols. Scan protocols included high resolution (360° rotation, 600 image frames, 120 kV[p], 5 mA, 7.4 seconds), standard (360°, 300 frames, 120 kV[p], 5 mA, 3.7 seconds), QuickScan (180°, 160 frames, 120 kV[p], 5 mA, 2 seconds), and QuickScan+ (180°, 160 frames, 90 kV[p], 3 mA, 2 seconds). Contrast-to-noise ratio was calculated as a quantitative measure of image quality for the various exposure options using the QUART DVT phantom. RESULTS Child phantom doses were on average 36% greater than adult phantom doses. QuickScan+ protocols resulted in significantly lower doses than standard protocols for the child (P = 0.0167) and adult (P = 0.0055) phantoms. The 13 × 16-cm cephalometric fields of view ranged from 11 to 85 μSv in the adult phantom and 18 to 120 μSv in the child phantom for the QuickScan+ and standard protocols, respectively. The contrast-to-noise ratio was reduced by approximately two thirds when comparing QuickScan+ with standard exposure parameters. CONCLUSIONS QuickScan+ effective doses are comparable with conventional panoramic examinations. Significant dose reductions are accompanied by significant reductions in image quality. However, this trade-off might be acceptable for certain diagnostic tasks such as interim assessment of treatment results.

[1]  H. Bosmans,et al.  Comparison of spatial and contrast resolution for cone-beam computed tomography scanners. , 2012, Oral surgery, oral medicine, oral pathology and oral radiology.

[2]  W D McDavid,et al.  Radiobiologic risk estimation from dental radiology. Part I. Absorbed doses to critical organs. , 1988, Oral surgery, oral medicine, and oral pathology.

[3]  S. Brooks,et al.  Dosimetry of two extraoral direct digital imaging devices: NewTom cone beam CT and Orthophos Plus DS panoramic unit. , 2003, Dento maxillo facial radiology.

[4]  D. Brenner,et al.  Computed tomography--an increasing source of radiation exposure. , 2007, The New England journal of medicine.

[5]  M. Cristy,et al.  Active bone marrow distribution as a function of age in humans. , 1981, Physics in medicine and biology.

[6]  Thorsten Grünheid,et al.  Dosimetry of a cone-beam computed tomography machine compared with a digital x-ray machine in orthodontic imaging. , 2012, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[7]  M. Ivanovic,et al.  Comparative dosimetry of dental CBCT devices and 64-slice CT for oral and maxillofacial radiology. , 2008, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[8]  D. Miglioretti,et al.  Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. , 2009, Archives of internal medicine.

[9]  S. Kapila,et al.  The current status of cone beam computed tomography imaging in orthodontics. , 2011, Dento maxillo facial radiology.

[10]  N Shandala,et al.  Scope of radiological protection control measures. , 2007, Annals of the ICRP.

[11]  J. Ludlow,et al.  Patient risk related to common dental radiographic examinations: the impact of 2007 International Commission on Radiological Protection recommendations regarding dose calculation. , 2008, Journal of the American Dental Association.

[12]  Jack Valentin,et al.  The 2007 Recommendations of the International Commission on Radiological Protection. ICRP publication 103. , 2007, Annals of the ICRP.

[13]  D. Brenner,et al.  Estimated risks of radiation-induced fatal cancer from pediatric CT. , 2001, AJR. American journal of roentgenology.

[14]  W D McDavid,et al.  Radiobiologic risk estimation from dental radiology. Part II. Cancer incidence and fatality. , 1988, Oral surgery, oral medicine, and oral pathology.

[15]  S. Brooks,et al.  Dosimetry of 3 CBCT devices for oral and maxillofacial radiology: CB Mercuray, NewTom 3G and i-CAT. , 2006, Dento maxillo facial radiology.

[16]  Tohru Kurabayashi,et al.  A comparative study for spatial resolution and subjective image characteristics of a multi-slice CT and a cone-beam CT for dental use. , 2011, European journal of radiology.

[17]  Ehsan Samei,et al.  Quantification of radiographic image quality based on patient anatomical contrast-to-noise ratio: a preliminary study with chest images , 2010, Medical Imaging.

[18]  R. Sievert,et al.  Book Reviews : Recommendations of the International Commission on Radiological Protection (as amended 1959 and revised 1962). I.C.R.P. Publication 6. 70 pp. PERGAMON PRESS. Oxford, London and New York, 1964. £1 5s. 0d. [TB/54] , 1964 .

[19]  V. Cassola,et al.  Standing adult human phantoms based on 10th, 50th and 90th mass and height percentiles of male and female Caucasian populations , 2011, Physics in medicine and biology.