title: Low-dose dental computed tomography: significant dose reduction without loss of image quality.
abstract: OBJECTIVE
  To measure and reduce the patient dose during computed tomography (CT) for dental applications.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Institute of Anatomy, University of Münster, Germany. peter.rustemeyer@uni-muenster.de
authors.forename: P
authors.initials: P
authors.lastname: Rustemeyer
authors.forename: U
authors.initials: U
authors.lastname: Streubühr
authors.forename: J
authors.initials: J
authors.lastname: Suttmoeller
mesh_terms: D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011861:Radiography, Dental / Q000379:methods / Q000592:standards*; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000592:standards*