胸部 X-線 撮影에서 診斷領域이 넓고 被曝線量을 輕減시킬 수 있는 方法을 강구하기 위하여 各管電壓 80Kvp와 120Kvp의 半價層에서부터 第1/8價層까지 구하여 각기 11.6㎜A1과 17.4㎜A1 附加濾過板을 부착시키고 종전에 使用하던 非整色性增減紙 필름시스템과 稀土類
增減紙시스템을 쓰고 特性曲線을 作成, 照射線量의 輕減率을 求하였다. 이 結果에 따라 胸部 X-線 撮影을 하면 肋骨과 縱隔洞, 心臟陰影이 消去되어 그에 가려진 病巢와 血管陰影이 鮮明하게 描寫되는 동시에 照射線量은 濾過板을 使用함으로써 約 1/3까지 輕減시킬 수 있어 高管電壓 撮影에는 附加濾過板을 使用해야 할 것이다.
더욱이 稀土類系 增減紙시스템인 G^^4/R^^XOG를 利用하면 感度가 增加되고 散亂線 含油率이 輕減되는 동시에 좋은 畵質値를 維持할 수 있었다.
Author has studied for finding method of decreasing radiation dose and increasing diagnostic range in chest X-ray radiography.
The study, for the added filter thickness from half value layer to 1/8 value layer by decreasing curve and research for the exposure factors, decreasing ratio of radiation dose, ratio of scatter ray and image quality in chest X-ray radiography.
The results were as follows :
1. By using the rate earth intensifying screen system at 120 Kvp, the sensitivity is increased by 4.5 times and the exposure ratio is decreased 0.22 by comparison with the Ca재^^4 intensifying screen system at 80 Kvp.
2. By using AⅠ added filter of 1/8 value layer, the scatter ray is increased more than no filter. But the scatter ray is decreased more in G^^4/R×OG intensifying system than in LT-Ⅱ/Rx intensifying system.
3. At 120 Kvp, the image quality value of G^^4/R×OG system is increased more than LT=Ⅱ/Rx system compared with slight decreasing image quality value at 80 Kvp.
Inclusion by using the added filter could decrease the radiation dose by 1/3 and obtain effective image quality with the added filter at high voltage hard exposure.