S状結腸癌のX線診断―ジャイロスコープを用いたルーチン大腸X線検査法

Radiological Diagnosis of Cancer of Sigmoid Colon: Routine X-ray examination of colon with Gyroscope

　近年，大腸X線診断は胃X線診断の確立とともに著しい発展をみせている．しかし，今までわれわれが胃X線診断で得た検査法を駆使しても，従来のX線透視撮影装置を用いての検査では直腸，上行結腸および盲腸部と同様にS状結腸は盲点の多い部位とされていた．

　1969年黒川および西山により開発されたユニバーサルX線透視撮影装置，ジャイロスコープ（東芝Model UG）を大腸X線検査に用いることにより，造影剤を容易に大腸各部に移動させることができ，かつ多方向撮影が可能となった．この結果，今まで検査が不十分となりがちであったS状結腸部も他の大腸の部位と同様に，ほぼ十分にその粘膜の状態を描出できるようになった．ここでは，まず，われわれが行なっているジャイロスコープを用いたroutine大腸X線検査法と，この検査法におけるS状結腸癌のX線診断およびその問題点について述べる．

　The recently developed gyroscope is particularly useful for the examination of the colon. Even the Sigmoid colon which has been considered as a blind spot by the conventional method can be evaluated easily. However, special attention should be paid to decreasing the exposure dose since the gonads are directly irradiated in this examination. On the other hand, it is essential to delineate as fully as possible the fine mucosal detail.

　To achieve this, we have developed a method using a gyroscope in addition to the automation of the examination. By this method the fluoroscopy time has been shortened with the decreased exposure dose as a result. The measured gonadal dose was 190～205 mR in a female and 55 mR in a male.

　The diagnostic capability of this method for cancers and polyps of the sigmoid colon were as follows;

　1) All of the 13 cancers including early cancer were detected.

　2) Twenty-three of 24 polyps were discovered. One measuring only 5 mm in the greatest diameter could not be detected.

　Particular care is needed in the long Sigmoid colon since even an advanced cancer can be hidden from view. An overdiagnosis of small polyps increases the false positive rate. Meticulous attention should be paid to adequate preparation for the examination of the colon and the interpretation of the films.