Low-dose dental computed tomography: significant dose reduction without loss of image quality

Purpose: To measure and reduce the patient dose during computed tomography (CT) for dental applications. Material and Methods: Lithium fluoride thermoluminescent dosimeters were implanted in a tissue-equivalent humanoid phantom (Alderson-Rando-Phantom) to determine doses to the thyroid gland, the active bone marrow, the salivary glands, and the eye lens. Dental CT was performed with spiral CT and a dental software package. The usual dental CT technique was compared with a new dose-reduced protocol, which delivered best image quality at lowest possible radiation dose, as tested in a preceding study. Image quality was analysed using a human anatomic head preparation. In addition, the radiation dose was compared with panoramic radiography and digital volume tomography (DVT). Eight radiologists evaluated all images in a blinded fashion. A Wilcoxon rank pair test was used for statistical evaluation. Results: Radiation dose could be reduced by a factor of 9 (max.) with the new dose-reduced protocol (e.g. bone marrow dose from 23.6 mSv to 2.9 mSv; eye lens from 0.5 mSv to 0.3 mSv; thyroid gland from 2.5 mSv to 0.5 mSv; parotid glands from 2.3 mSv to 0.4 mSv). Dose reduction did not reduce image quality or diagnostic information. Conclusion: A considerable dose reduction without loss of diagnostic information is achievable in dental CT. As radiation exposure of the presented low-dose protocol is expected to be in the same range as DVT, low-dose dental CT might be superior to DVT, because CT can be used to evaluate soft tissues as well.

[1]  R. Campani,et al.  Use of spiral computed tomography for multiplanar dental reconstruction. , 1997, Dento maxillo facial radiology.

[2]  S. Ekholm,et al.  Low-dose tomographic techniques for dental implant planning. , 1996, The International journal of oral & maxillofacial implants.

[3]  B. Mealey,et al.  The role of computerized tomography in dental implantology. , 1992, The International Journal of Oral and Maxillofacial Implants.

[4]  S. Ericson,et al.  The dental follicle in normally and ectopically erupting maxillary canines: a computed tomography study. , 2009, The Angle orthodontist.

[5]  R. Campani,et al.  The use of spiral computed tomography in the localization of impacted maxillary canines. , 1997, Dento maxillo facial radiology.

[6]  W. Heindel,et al.  Screening for early lung cancer with low-dose spiral computed tomography: results of annual follow-up examinations in asymptomatic smokers , 2004, European Radiology.

[7]  C. Lindh,et al.  Radiologic examination for location of the mandibular canal: a comparison between panoramic radiography and conventional tomography. , 1989, The International journal of oral & maxillofacial implants.

[8]  D. E. Clark,et al.  Radiation absorbed from dental implant radiography: a comparison of linear tomography, CT scan, and panoramic and intra-oral techniques. , 1990, The Journal of oral implantology.

[9]  D. Hatcher,et al.  Radiation absorbed in maxillofacial imaging with a new dental computed tomography device. , 2003, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[10]  H. Gröndahl,et al.  Quality of preimplant low-dose tomography. , 1999, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[11]  M. Cohnen,et al.  Radiation dose in dental radiology , 2002, European Radiology.

[12]  Roger T Staff,et al.  Advanced imaging: Magnetic resonance imaging in implant dentistry. , 2003, Clinical oral implants research.

[13]  H. Hohn,et al.  Niedrigdosis dental-CT , 1999 .

[14]  G. Santler,et al.  Indications and limitations of three-dimensional models in cranio-maxillofacial surgery. , 1998, Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery.

[15]  M W Vannier,et al.  Validation of spiral computed tomography for dental implants. , 1998, Dento maxillo facial radiology.

[16]  O Bahat,et al.  Treatment planning and placement of implants in the posterior maxillae: report of 732 consecutive Nobelpharma implants. , 1994, The International journal of oral & maxillofacial implants.

[17]  J G Hunt,et al.  The validation of organ dose calculations using voxel phantoms and Monte Carlo methods applied to point and water immersion sources. , 2004, Radiation protection dosimetry.

[18]  K. Mosier,et al.  Dosimetry and cost of imaging osseointegrated implants with film-based and computed tomography. , 1997, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.

[19]  J. Abrahams,et al.  Anatomy of the jaw revisited with a dental CT software program. , 1993, AJNR. American journal of neuroradiology.

[20]  E. Lam,et al.  Comparison of two-dimensional orthoradially reformatted computed tomography and panoramic radiography for dental implant treatment planning. , 1995, The Journal of prosthetic dentistry.

[21]  W. McDavid,et al.  Absorbed dose determination for tomographic implant site assessment techniques. , 1992, Oral surgery, oral medicine, and oral pathology.

[22]  F. Shafiei,et al.  Artifacts from Dental Casting Alloys in Magnetic Resonance Imaging , 2003, Journal of dental research.

[23]  P. Mozzo,et al.  A new volumetric CT machine for dental imaging based on the cone-beam technique: preliminary results , 1998, European Radiology.

[24]  W. Kalender,et al.  Evaluation of section sensitivity profiles and image noise in spiral CT. , 1992, Radiology.

[25]  D. E. Clark,et al.  Effective dose from radiation absorbed during a panoramic examination with a new generation machine. , 2000, Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics.