全口牙電腦斷層已成為牙醫師在植牙與牙齒治療精準度的最佳工具。牙科輻射防護之觀念應做到合理抑低之 最終原則。本研究利用光激發光劑量計(Optically Stimulated Luminescence Dosimeter, OSLD)佈點在ICRP 60 及103 報告建議頭頸部假體之危急器官，進行全口牙電腦斷層攝影及全口牙放射攝影，測量頭頸部各器官對應位置之淺 部(皮下0.007 cm)、水晶體部(皮下0.3 cm)、深部等價劑量(皮下1 cm)，測得全口牙電腦斷層等價劑量最高為水晶 體部齒槽47.819 mSv；全口牙放射攝影等價劑量最高為水晶體部齒槽0.297 mSv。根據器官之組織加權因數推算 出全口牙電腦斷層有效劑量最高為水晶體部劑量3.138 mSv，全口牙放射攝影有效劑量最高為水晶體部劑量0.052 mSv。全口牙電腦斷層機率效應風險一般民眾最高為2.403×10-4，全口牙放射攝影機率效應風險一般民眾最高為 3.792×10-6。全口牙電腦斷層攝影每次所接受的有效劑量約3 mSv，全口牙放射攝影每次約0.05 mSv；可知民眾作 一次全口牙放射攝影約為2 次胸腔X 光攝影的劑量而一次全口牙電腦斷層大約等於150 次胸腔X 光攝影的劑量； 台灣民眾平均每天接受約0.0043 mSv 背景輻射，全口牙放射攝影約一天天然背景輻射的11 倍，全口牙電腦斷層 約一天天然背景輻射的697 倍。 本研究認為牙科放射攝影的輻射健康效應風險是比一般診斷X 光還低，但全口牙電腦斷層有效劑量高於台灣 民眾每年每人接受天然背景輻射線及一般人年劑量限制，故牙醫師開立全口牙電腦斷層檢查之時機及必要性建議 訂定規範，即使為了診斷與治療需要，仍需保有一定的輻射防護觀念，且在維持一定的影像品質前提下，降低攝 影條件來減低患者輻射劑量將是未來研究的方向。

In this study, we used an optically stimulated luminescence dosimeter (OSLD) to locate head and neck phantoms, which are the critical organs, and recommended ICRP 60 and 103. While executing dental CT and panoramic x-rays, measurements of the shallow dose (0.007 cm), lens dose (0.3 cm), and deep dose (1 cm) were equivalent to the head and neck position corresponding to each organ. The maximum doses equivalent to dental CT and panoramic x-rays were then calculated. The results showed that the highest equivalent dose was 47.819 mSv in the alveolar of the lens by dental CT and 0.297 mSv by panoramic x-ray. The highest effective dose was 3.138 mSv in the dental CT lens dose, whereas the highest effective dose was 0.052 mSv in the panoramic x-ray lens dose. The highest risk for the probability of effect of general public was 2.403×10-4 in Dental CT. The highest risk for the probability of effect of general public was 3.792×10-6 in Panoramic x-ray. The maximum equivalent dose was 3.766 mSv in the lens of dental CT and 0.115 mSv in the lens of panoramic x-rays. Both levels were lower than the individual annual dose limit, which is approximately a 3 mSv effective dose for dental CT and 0.05 mSv effective doses for panoramic x-rays. One panoramic x-ray dose is approximately twice that of a chest x-ray and one dental CT dose is approximately 150 times that of a chest x-ray. Taiwanese received the average background radiation about 0.0043 mSv one day. One panoramic x-ray is equal to approximately 11 times the background radiation in Taiwan. One dental CT is equal to approximately 697 times the background radiation in Taiwan. This study shows that the risk of radiation health effects from dental radiography is lower than General diagnostic X-rays. However, the effective dose of dental CT is higher than background radiation levels and the dose should be limited to one per person per year in Taiwan. Therefore, it is necessary for dentists to regulate and set the norms by time and necessity when ordering an examination by dental CT. Although the diagnosis and treatment are of paramount importance, dentists still need to consider the concept of radiation protection. In doing so, they can adopt a new way to maintain a certain image quality and adjust exposure conditions to minimize radiation exposure.