Background: Intraoral radiographies are the most frequent X-ray examinations in humans.
According to International Commission on Radiation Protection (ICRP) recommendations, the
selection of a diagnostic reference level (DRL) should be specific to a country or region. Critical
organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures
should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral
radiography, a National Radiation Protection Department-sponsored pilot study was carried out.
Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be
the recommended method for measuring entrance surface doses (ESD). In this study, ESD was
measured using LiF thermoluminescent dosimeters (TLD-100) on the skin (either mandibular or
maxillary arcs) of 40 patients. Three TLD chips were placed on the skin of each patient. The
doses were averaged for each radiography and mean ESD of all patients calculated.
Results: The mean ± SD entrance surface dose at the center of the beam on the patients' skin in
intraoral radiography was 1.173 ± 0.606 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD
for male and female patients were 1.380 ± 0.823, and 1.004 ± 0.258 respectively. No statistically
significant difference was found between these means. Despite its necessity, in national
level, there is no published data on the diagnostic reference levels for intraoral radiography.
However, the results obtained in this study are lower than those reported by investigators in
other countries.
Conclusion: In IR Iran, due to lack of large scale studies, no diagnostic reference levels have
been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it
is not possible to clarify whether in intraoral radiographies any dose reduction techniques are
needed. We intend to perform similar nationwide studies to set the diagnostic reference level for
intraoal radio graphy
