투시촬영에서 바륨 조영제와 팬텀 두께에 따른 DAP 변화

DAP Variation with Barium Contrast and Phantom Thickness in Fluoroscopy

투시 검사 시 바륨 조영제의 농도변화와 유무, 두께에 따른 피폭선량의 변화를 측정하고자 하였다. 선량평가를 위하여 중앙에 아크릴 큐브 (5 × 5 × 10 ㎝)를 넣을 수 있으며, 1 cm씩 두께를 변화할 수 있는 아크릴 팬텀 (25 × 30 × 30 cm)을 제작하였다. 아크릴 큐브에는 11 개 (100∼200% w/v) 농도의 바륨 현탁액 150 ml를 넣을 수 있도록 하였다. AEC, SID 115cm, FOV 30 x 30cm, 15 P/s, Filter Cu 0.2 mm의 촬영조건을 사용하여 아크릴판을 1 장씩 제거하면서 15cm까지 두께를 감소시켜 투시를 1 분간 시행하였으며, Spot 촬영하여 DAP를 측정하였다. 동일한 방법으로 조영제 유무와 농도에 따라 실험하였으며, 재현성을 위하여 각 실험은 5 회 반복 실험되었다. 연구결과 바륨 농도에 따른 DAP 변화는 보이지 않았으며, 바륨을 사용함에 따라 Fluoroscopy와 Spot촬영에서 각각 1.28 배와 1.15배 증가하였으며, 팬텀의 두께가 15 cm에서 25 cm로 증가했을 때 Fluoroscopy에서 4.76 배증가되었으며, Spot에서는 4.86 배로 증가되었으며 이는 통계적으로 유의하였다(p > 0.05). 비만환자의 경우 투시촬영 시 과도한 방사선 피폭이 예상되므로 UGI보다 민감도와 특이도가 높은 내시경을 하는 것이 좋을 것으로 사료된다.

In the fluoroscopic examination, the presence or absence of a change in the concentration of barium contrast agent and the change in exposure dose according to the thickness were measured. For dose assessment, an acrylic phantom (25 × 30 × 30 cm) was fabricated that could put an acrylic cube (5 × 5 × 10 cm) in the center and vary the thickness by 1 cm. The acrylic cube was made to contain 150 ml of a barium suspension of 11 (100-200% w/v) concentration. AEC, SID 115 cm, FOV 30 × 30 cm, 15 P/s, Filter Cu 0.2 mm shooting conditions were used. One minute trans-illumination was performed with one acrylic plate removed until the thickness was reduced to 15 cm. Spot shooting was performed to measure DAP. In the same way, the experiment was carried out depending on the presence or absence of the contrast agent. Each experiment was repeated five times for reproducibility. As a result, there was no change in DAP according to the concentration of the barium contrast agent. The results of fluoroscopy and spot imaging increased 1.28 times and 1.15 times, respectively, by using the barium contrast agent. As the thickness of the phantom increased from 15 cm to 25 cm, the results of fluoroscopy and spot imaging were increased by 4.76 and 4.86 times, respectively. This was statistically significant (p>0.05). In obese patients, fluoroscopy is expected to result in excessive radiation exposure. Therefore, endoscopy with higher sensitivity and specificity than UGI is recommended.