파노라마 촬영시 두경부 주요기관에 대한 흡수선량 분포

DISTRIBUTION OF ABSORBED DOSES TO THE IMPORTANT ORGANS OF HEAD AND NECK REGION IN PANORAMIC RADIOGRAPHY

PanelipseⅡ 파노라마 방사선사진 촬영시 두 경부 주요기관의 방사선 흡수선량 분포를 평가하기 위하여 LiF(TLD-100/sup R/) 열발광선량계를 phantom (RT-210 Humanoid Head & Neck Section/sup R/)내부의 중요 해부구조물과 피부표면에 위치시켜 관전류 4㎃와 노출시간 20초의 조건하에서 관전압변화(65kVp. 75kVp, 85kVp)에 따른 방사선 흡수선량을 측정하여 아래와 같은 결론을 얻었다. 내부해부구조물의 방사선 흡수선량은 비인강부위에서 104mGy, 1.065mGy, 2.09mGy로써 가장 높게 나타났고 이하선의 내엽부위에서는 0.525mGy, 0.579mGy, 1.108mGy로, 악하선부위에서는 0.481mGy, 0.608mGy, 1.191mGy로 비교적 높게 나타났으며 85kVp에서만 흡수선량이 측정된 안구와 갑상선부위는 0.172mGy와 0.128mGy로써 비교적 낮게 나타났다. 피부표면의 방사선 흡수선량은 제1경추 후방부위에서 1.263mGy, 1.538mGy, 2.952mGy로써 가장 높게 나타났고 이하선부위에서는 0.267mGy, 0.401mGy, 0.481mGy로 비교적 높게 나타났으며 인중부위는 0.057mGy, 0.068mGy, 0.081mGy, 85kVp에서만 흡수선량이 측정된 턱의 중앙부위는 0.059mGy로써 비교적 낮게 나타났다. 관전압 증가에 따른 내부해부구조물의 방사선 흡수선량 증가는 65kVp에서 75kVp로 증가함에 따라 1.1배로 나타났으며, 76kVp에서 85kVp로 증가시에는 1.9배로 나타났다. 관전압 증가에 따른 피부표면의 방사선 흡수선량 증가는 65kVp에서 75kVp로 증가함에 따라 1.3배로 나타났으며, 75kVp에서 85kVp로 증가시에는 1.6배로 나타났다.

The purpose of this study was to estimate the distribution of absorbed doses of each important organs of head and neck region in panoramic radiography. Radiation dosimetry at internal anatomic sites and skin surfaces of phantom (RT-210 Humanoid Head & Neck Section/sup R/) was performed with lithium fluoride (TLD-100/sup R/) thermoluminescent dosimeters according to change of kilovoltage (65kVp, 75kVp and 85kVp) with 4 miliamperage and 20 second exposure time. The results obtained were as follows; Radiation absorbed doses of internal anatomic sites were presented the highest doses of 1.04 mGy, 1.065 mGy and 2.09 mGy in nasopharynx, relatively high doses of 0.525 mGy, 0.59 mGy and 1.108 mGy in deep lobe of parotid gland, 0.481 mGy, 0.68 mGy and 1.191 mGy in submandibular gland. But there were comparatively low doses of 0.172 mGy and 0.128 mGy in eyes and thyroid gland that absorbed dose was estimated at 85kVp. Radiation absorbed doses of skin surfaces were presented the highest doses of 1. 263 mGy, 1.538 mGy and 2.952 mGy in back side of first cervical vertebra and relatively high doses of 0.267 mGy, 0.401 mGy and 0.481 mGy in parotid gland. But there were comparatively low doses of 0.057 mGy, 0.068 mGy and 0.081 mGy in philtrum and 0.059 mGy in middle portion of chin that absorbed dose was estimated at 85kVp. According to increase of kilovoltage, the radiation absorbed doses were increased 1.1 times when kilovolt age changes from 65kVp to 75kVp and 1.9 times when kilovolt age changes from 75kVp to 85kVp at internal anatomic sites. According to increase of kilovoltage, the radiation absorbed doses were increased 1.3 times when kilovolt age changes from 65kVp to 75kVp and 1.6 times when kilovoltage changes from 75kVp to 85kVp at skin surfaces.