Shielding effect of thyroid collar for digital panoramic radiography

Abstract

Objectives: To evaluate the shielding effect of thyroid collar for digital panoramic radiography. Methods: 4 machines [Orthopantomograph ® OP200 (Instrumentarium Dental, Tuusula, Finland), Orthophos CD (Sirona Dental Systems GmbH, Bensheim, Germany), Orthophos XG Plus (Sirona Dental Systems GmbH) and ProMax ® (Planmeca Oy, Helsinki, Finland)] were used in this study. Average tissue-absorbed doses were measured using thermoluminescent dosemeter chips in an anthropomorphic phantom. Effective organ and total effective doses were derived according to the International Commission of Radiological Protection 2007 recommendations. The shielding effect of one collar in front and two collars both in front and at the back of the neck was measured. Results: The effective organ doses of the thyroid gland obtained from the 4 panoramic machines were 1.12 mSv for OP200, 2.71 mSv for Orthophos CD, 2.18 mSv for Orthophos XG plus and 2.20 mSv for ProMax, when no thyroid collar was used. When 1 collar was used in front of the neck, the effective organ doses of the thyroid gland were 1.01 mSv (9.8% reduction), 2.45 mSv (9.6% reduction), 1.76 mSv (19.3% reduction) and 1.70 mSv (22.7% reduction), respectively. Significant differences in dose reduction were found for Orthophos XG Plus and ProMax. When two collars were used, the effective organ doses of the thyroid gland were also significantly reduced for the two machines Orthophos XG Plus and ProMax. The same trend was observed in the total effective doses for the four machines. Conclusions: Wearing a thyroid collar was helpful when the direct digital panoramic imaging systems were in use, whereas for the indirect digital panoramic imaging systems, the thyroid collar did not have an extra protective effect on the thyroid gland and whole body.

Korean dentists’ perceptions and attitudes regarding radiation safety and protection

“…The use of lead aprons or thyroid collar shielding in panoramic radiography is controversial; 32,33 however, a recent study showed that thyroid shielding is helpful in reducing radiation exposure when performing upper anterior tooth radiography. 34 The ADA recommends that protective thyroid collars be used whenever possible.…”

Are Bismuth Shields Useful in Dentomaxillofacial Radiology Practice for the Protection of Eyes and Thyroid Glands from Ionizing Radiation?

“…The increase in the thyroid dose in this study (602.94%) in OPTG scanning with the use of bismuth shielding may be explained by backscatter radiation as well. Han et al (22) reported a 9.6-22.7% reduction in thyroid dose with the use of leaded shielding in OPTG scanning. However, no studies have been conducted using bismuth shielding.…”

The analysis of the subjective image quality of a dental radiogram obtained with a digital and film detector

“…Iako su doze zra enja smanjene zbog razvoja digitalnih tehnika, radiografska dentalna dijagnostika i dalje je jedan od naj eš ih tipova radioloških snimanja koji se esto obavljaju pri stomatološkim pregledima (10)(11)(12)(13).…”