100万画素CCDカメラを搭載したⅠ.Ⅰ.-DRシステムによる小照射野Ⅹ線骨盤計測法 ―Guthmann法への適用に関する検討―

100万画素CCDカメラを用いたI.I.-DR装置(CC･DRシステム)をX線骨盤計測に適用するため,被曝線量をはじめとするいくつかの点を検討した｡照射野内の被曝線量は従来の高感度Screen-Film システムであるG12/HRSと同等以下に抑えることが可能であった｡また,CC･DRシステムの9インチ円形照射野は一般的に用いられている大角フィルム面積の1/3であり,胎位の95%を占めるといわれている頭位の撮影においては胎児の生殖腺はもちろん, 赤色骨髄を多く含む脊椎への被曝を大幅に低減できた｡また,新たに開発された距離計測ソフトウェアーの正確度は良好で,通常lmm以下の誤差で測定が可能であることを確認した。その他,装置に標準装備されている自動露出機構の特性についても報告し,最後に撮影時の留意点についても検討した｡

To apply CC･DR system (image intensifier digital radiography system including one million pixel CCD camera)to X-ray pelvimetry, We examined exposure dose of X-ray, radiation field, and accuracy of X-ray pelvimetry by the system. The hazards of radiation by CC･DR system were less than those of radiation by G12/HRS which is high sensitive screen-film system. 9 inch round radiation field by CC・DR system was one third of the area of 14×14 inch film. In cephalic presentation which occurs in about 95% of pregnancies, the damages of radiation by CC･DR system to fetal gonads and spinal bones including bone marrow much were less than those by usual X-ray examination. The accuracy of a distance measuring software devised newly for pelvimetry was reliable, and we could measure diameters with less than 1 mm deviations. Also we report the characteristics of automatic exposure controller annexed to this TV system and enumerate points to which we pay attention on taking a radiograph. Furthermore, It is expected that CC･DR system was useful to apply to superio-interior pelviography (Martius).