title: Establishment of local diagnostic reference levels for quality control in intraoral radiography.
abstract: OBJECTIVE
  To investigate the dosage and imaging conditions for patients undergoing intraoral radiography at Meikai University Hospital and establish assurance and quality control data.
  
  
  METHODS
  Tube voltage, exposure time, and air kinetic energy released per unit mass (air kerma) of three intraoral radiography units were measured. To calculate the patient entrance dose (PED) for each radiograph using Insight film, we extracted data for 1063 patients from their exposure records. The PED was compared with the diagnostic reference level (DRL) from the European Commission and the UK.
  
  
  RESULTS
  The tube voltage of the three units was maintained at 60 ± 2 kV. Differences in exposure time were less than 1.7 % for all units. The air kerma rates were well maintained within a 4.2 % error. Based on the patient data, there were no significant differences in the mean exposure times for males and females for all anatomical sites. The mean PED ranged from 1.09 ± 0.31 mGy for the mandibular incisors to 2.42 ± 0.33 mGy for the maxillary molars. The mean PED at the mandibular molars using InSight film was 1.59 ± 0.20 mGy, being less than the recommended value based on the DRL for intraoral radiography in the UK.
  
  
  CONCLUSIONS
  We concluded that radiographic conditions at the hospital have been properly maintained. This basic quality control data may assist other dental radiation facilities to reduce patient dosage.
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Izawa
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Harata
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Shiba
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Koizumi
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ozawa
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Nobutoshi
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Division of Dental Radiology, Department of Diagnostic and Therapeutic Science, Meikai University School of Dentistry, 1-1 Keyakidai, Sakadoshi, Saitama 350-0283 Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Okumura
keywords: Diagnostic reference level (DRL); Intraoral radiography; Patient entrance dose (PED); Radiation dosage