조사야에 따른 CBCT의 흡수선량 비교

Abstract

Objectives: To compare the absorbed doses of cone beam computed tomography (CBCT) in different fields of view (FOV). Methods: To measure the absorbed doses of CBCT (CB MercuRay, Hitachi medical corporation, Tokyo, Japan), we placed TLD chips at the both submandibular and parotid gland, esophagus, tongue and thyroid gland regions in dental head phantom (CIRS, USA). We used three image acquisition modes with different sizes of field of view : Panoramic mode (P mode), Implant mode (I mode), Dental mode (D mode). And two different dental mode scannings were performed. One was scanning of the right upper molar region (D1), and the other was scanning of left lower molar region (D2). Results: The avarage of absorbed doses was least in D mode (average of D1 and D2, 4272.1 μGy) (p < 0.05). And although the avarages of absorbed doses between D1 and D2 showed no significant difference (p > 0.05), the absorbed doses of esophagus (D1 756.9 μGy, D2 2938.2 μGy) and thyroid gland (D1 344.6 μGy, D2 880.1 μGy) displayed difference between D1 and D2. Conclusions: Because the avarage of absorbed doses was least in smallest FOV, when taking CT, we must try to select the FOV as small as possible, followed by careful diagnosis.

Keywords: thermoluminescent dosimetry; Cone-Beam Computed Tomography; radiation dosage