原文題目(出處)：

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口腔病理科 On-Line KMU Student Bulletin

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原文題目(出處)： Clinical evaluation of dose reduction on image quality of panoramic radiographs. J Contemp Dent Pract 2008;9:34-41.

原文作者姓名： Alkurt MT, Peker I, Usalan G, Altunkaynak B

通訊作者學校： Ethics Committee of Gazi University, Faculty of Dentistry, Ankara, Turkey

報告者姓名(組別)： 林修篁 (Intern F 組)

報告日期： 2008/08/18

內文：

Purpose：The purpose of this study was to evaluate the effect of tube current

reduction on image quality using medium and regular intensifying screens as well as a digital system for panoramic radiography.

Methods and materials：A total of 150 panoramic images of 75 patients (41 female

and 34 male) were obtained in the study. Exclusion criteria were pregnancy, age 17 years or less, occupational X-ray exposure, and patients with previous extensive radiographic examinations. The patients were divided into five groups with each having 15 subjects. The initial images were taken at standard exposure settings, and

secondary images were exposed with the tube current reduced at different rates.

Table 1. Screen-digital system combinations and mA settings in the study.

All radiographs were assessed by three oral radiologists with at least ten years of experience each. The observers evaluated the images using a three-point scale1 (1=well visible, 0=partly visible, and -1=not or hardly visible) for anatomical structures and pathological findings (Table 2) which are commonly found on panoramic radiographs.

Table 2. Evaluated anatomical structures and pathological findings.

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Results：There was no statistically significant difference (p>0.05) between the two

exposures for Group 3 (the rate of dose reduction 25%) while a statistically significant difference (p<0.05) was found in Group 4 (the rate of dose reduction 50%) using medium intensifying screens for all observers. No statistically significant difference was found between the two exposures on digital panoramic images.

Conclusion:

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1. According to the results of this study, dose reduction caused loss of image quality using regular intensifying screens when the tube current was reduced by 33.3% and 46.6%. In further studies, the reduction of tube current could be limited to only 16.6%.

2. A 25% dose reduction was achieved with a medium intensifying screen and digital panoramic radiography without any loss of image quality of either anatomical structures or pathological findings.

3. In further studies the reduction of tube current may be reduced by 37.5% using medium intensifying screens and by 50% for digital panoramic images.

題號題目

1

關於TMJ的病變，何者為全關節置換術的適應症？

(A) 可復原的關節盤前移

(B) Mental foramen (C) Coronoid process (D) Frontal sinus

答案(D) 出處：Oral Radiology P.201~209 題號題目

2

何種影像在需要包含大範圍顎骨時最常使用？

(A) Panoramic images

(B) Lateral cephalometric projection (C) Waters projection

(D) Computed tomography 答案(A) 出處：Oral Radiology P.191