Dose Comparisons

Exposure from diagnostic imaging is often compared to environmental exposure from naturally occurring radiation and other artificial sources such as consumer products. Collectively these natural and artificial sources are described as background radiation. A typical four-film bitewing survey using PSP receptors or F speed film and rectangular collimation is equivalent to approximately a half day of background radiation.9 More commonly, D speed film and round collimation are used for bitewing imaging with a background radiation equivalent of 2 days. By comparison, a panoramic survey is equivalent to approximately a half to full day of background radiation depending on the machine and background radiation standards.9 Unlike intraoral digital imaging, the use of digital receptors for panoramic imaging does not result in significant dose reduction compared to film-based panoramic systems using rare earth intensifying screens.10,11