Application of niobium in dental radiography

In the 1990s, digital radiography technology has not been widely popularized for dental diagnosis, treatment of X-ray imaging system is still in the application of film development, how to ensure image quality under the premise of reducing the patient's radiation dose has been the direction of researchers. Many scholars have tried to apply niobium-based filters to reduce the radiation dose to patients, and Price et al. found that niobium-based filters increase the film sensitivity, reduce the X-ray beam, and the film contrast is not affected by the quality of the beam current, and White et al. demonstrated that niobium-based filters can reduce the radiation dose by 20% to 30%, and also proved that the image quality of D-speed photographic film is slightly affected, and the image quality of E-speed photographic film is slightly affected. McDonnell et al. showed that niobium-based filters reduce radiation in the shallow zone (2 cm), but increase radiation in the deeper zone (6 cm).

Byrne et al.'s study of skin radiation exposure and thyroid radiation dose distribution after application of niobium-based filters showed that niobium-based filters significantly reduced skin surface radiation exposure, but failed to reduce exposure to the deeper thyroid gland, and even increased exposure to one part of the thyroid gland. Scarfe et al. also showed that niobium-based filters lead to elevated radiation doses in deep soft tissues, such as the thyroid gland. Therefore, there are different opinions on the rationality and necessity of applying niobium-based filters.

Tetradis et al. argued that the application of niobium-based filters not only leads to a stiff radiation beam, but also increases the radiation time, causes dynamic blurring, and reduces the contrast of the image, and Bianchi et al. analyzed the experimental results using a square-wave response function and argued that, although the niobium-based filters can reduce the surface dose of radiation to a certain degree compared with the traditional aluminum-based filters, the risk of increasing the radiation dose to the deeper soft tissues, the cost, wear and tear, and the increase in radiation dose to the deeper soft tissues, have all been considered as important factors. The risk of increased radiation to deeper soft tissues, as well as the increased cost and wear and tear, make the application of niobium-based filters more costly than it is worthwhile.

In terms of the effect of niobium-based filters on imaging quality, some scholars have also done research. wakoh et al. used the modulation transfer function to analyze the imaging contrast before and after the application of niobium-based filters and found that there was only a small degree of reduction in the imaging contrast; niobium-based filters do not significantly reduce the quality of the image when compared with aluminum-based filters. borden et al. found that whether or not to apply niobium-based filters has a significant impact on the diagnosis of orthodontic stainless steel. Borden et al. found that the application of niobium-based filters had no significant effect on the diagnosis of density differences in aluminum specimens under the archwire. With the development of digital radiography technology, high definition, low radiation dose oral X-ray imaging technology has gradually become possible, niobium-based filters in the field of oral radiology application of research has gradually faded out of people's field of vision.