牙科電腦斷層攝影之臨床劑量量測與分析

In-vivo dose measurement and analysis of dental computed tomography

彭炳儒(Bing-Ru Pen)

指導教授 ： 鄭凱元

中臺科技大學/健康科學院/放射科學研究所/碩士(2010年)

摘要

植牙手術前，病患必須先進行牙科攝影的檢查，其主要目的是透過影像的導引進行植牙計畫之模擬，然而，眾多攝影檢查中又以近期快速成長的3D- CBCT(3-dimentional cone beam computed tomography)最受矚目，而3D- CBCT之有效劑量以及輻射風險已有許多文獻利用擬人之藍道假體進行數據之量測與探討，本實驗將針對3D- CBCT 進行臨床劑量的量測。
本研究所使用之儀器為i-CAT 3D- CBCT，量測之組別依據牙醫師開設之攝影條件而定，分別為全顱攝影、上顎攝影以及下顎攝影，此三種檢查之病患量各為10人，共30人。另較特殊之攝影法為下顎高解析度攝影及全顱分段攝影等兩組，該兩組之病患量各為3人，共6人。
研究結果顯示，全顱攝影所造成之入射表面劑量為1820 μGy，上顎攝影為480 μGy，下顎攝影為369 μGy，下顎高解析攝影為1025 μGy，全顱分段攝影為588 μGy。結果顯示，於全顱攝影時病患所受之劑量明顯偏高，若非必要，應盡可能避免。此外，於量測中亦發現，全顱攝影與下顎攝影對甲狀腺區域造成之入射劑量較高(220~407 μGy)，故建議為病患增加甲狀腺屏蔽以避免該甲狀腺接受不必要的劑量。

關鍵字

輻射度量 ； 入射表面劑量 ； 熱發光劑量計 ； 牙科電腦斷層

並列摘要

All patients must go through dental x-ray or 3-dimentional cone beam computed tomography (3D- CBCT) in any dental pretreatment in most hospitals. The purpose is to simulate the implantation of the teeth with image-guiding, therefore many 3D-CBCT examination have been rapidly growing. The effective dose and the radiation risk have been discussed in previous literature by using Rando phantom to measure and analyze the results. This experiment was probing into clinical dose measurement with the 3D-CBT.
Thirty six patients were divided into five groups which took different examinations which respectively were maxilary, mandible, high-resolution mandible examination, full head, and full head section photography. All examinations were performed by i-CAT CBCT and were measured by TLD-100 (LiF:Mg,Ti) dosimeters. They were placed over the lateral orbit, infraorbital foramen, parotid gland, mandibular angle, thyroid gland, and neck vertebrae of each patient to measure the surface dose.
In this study, the results showed that the entrance surface dose was 1820 μGy in the full head examination, 480 μGy in the maxillary examination, 369 μGy in the mandible examination, 1025 μGy in the high-resolution mandible examination, 588 μGy in the full head section photography. The surface dose was also measured in the thyroid area, and it was relatively high ( 220μGy~407μGy).

並列關鍵字

TLD ； Radiation dosimetry ； Entrance surefacr dose (ESD) ； Cone beam computed tomography (CBCT)

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