Frequent, low-dose, improved-contrast radiographic images with the use of narrow x-ray beams.
Conventional dental radiography uses 60 mm-wide x-ray beams that irradiate the cheeks. To reduce the dose of radiation, months or years can separate serial films and prevent short-term assessment of disease activity. A technique that uses a 13 mm narrow x-ray beam that avoids the cheeks was compared with a wide x-ray beam by using a contrast phantom, a cheek substitute, and a serially sectioned dry mandible. Phantom contrast was measured densitometrically at 50 kVp, 65 kVp, and 90 kVp with wide x-ray beam and narrow x-ray beam and with and without cheek scatter. The narrow x-ray beam without cheek scatter technique resulted in better contrast (0.06 to 0.04 OD) than the wide x-ray beam with cheek scatter (0.05 to 0.02 OD). A posterior interdental crest was irradiated and a trabecular rod was removed. The bone detail was best in the images produced with the narrow x-ray beam without cheek scatter. The area of the narrow x-ray beam was 4.35% of the area of the wide x-ray beam with approximately 5% of the dose. Short-interval (weekly), very-low-dose radiography should be possible with improved contrast to assess alveolar bone changes.
Benn
D K
DK
Department of Dental Radiology, Guy's Hospital, University of London, England.
D002610:Cheek / Q000000981:diagnostic imaging; D003287:Contrast Media; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging; D008961:Models, Structural; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D011861:Radiography, Dental / Q000295:instrumentation / Q000379:methods*; D012542:Scattering, Radiation; D013997:Time Factors; D014965:X-Rays
D003287:Contrast Media