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Tissue radiation dosages using the RVG-S with and without niobium filtration
W C Scarfe1, A G Farman, J W Brand
1Department of Diagnosis and General Dentistry, University of Louisville, School of Dentistry, Kentucky 40292, USA.
Australian Dental Journal
|December 31, 1997
Summary
New dental imaging technology, the RVG-S, significantly reduces patient radiation dose compared to E-speed film. Adding niobium filtration further lowers skin entrance dose, but may increase thyroid radiation exposure.
Area of Science:
- Radiology
- Dental Imaging
- Radiation Dosimetry
Background:
- Dental radiography is a common diagnostic tool.
- Minimizing patient radiation exposure is crucial in dental imaging.
- Evaluating new imaging technologies for dose reduction is essential.
Purpose of the Study:
- To measure and compare tissue doses in a head-and-neck phantom using E-speed film and the RVG-S system.
- To assess the impact of aluminum and niobium filtration on radiation dose reduction.
- To evaluate dose variations at specific anatomical sites, including salivary glands and thyroid.
Main Methods:
- Tissue doses were measured using an ionization chamber in a modified Rando phantom.
- Imaging was performed with E-speed film and the RVG-S, with and without niobium filtration.
- Standardized aluminum filtration was used with both imaging modalities.
- Reproducible exposure settings were established using a dental mannequin.
Main Results:
- The RVG-S system reduced average skin entrance dose by 31-39% with aluminum filtration and 51-60% with added niobium filtration.
- Dose reductions at deeper tissue sites were observed but were specific to location and projection.
- Cumulative dose reduction with RVG-S (without niobium) was 32%, and 42% with added niobium filtration.
- Niobium filtration led to increased radiation dosage in deeper soft tissues, such as the thyroid gland.
Conclusions:
- The RVG-S system offers significant radiation dose reduction for dental imaging compared to E-speed film.
- Niobium filtration enhances dose reduction at the skin entrance but requires careful consideration due to potential increases in deep tissue dose.
- Further research may be needed to optimize filtration for comprehensive dose reduction across all tissues.