术前确定下胃肠道出血病人的出血部位仍是临床上的难题。传统的钡剂检查,约30％的病人不能对其潜在的出血部位定位。即使病灶已判明,但不能肯定它是出血来源。结肠镜虽能用来诊断,可由于大量的出血致使视野模糊而不实用。选择性血管造影是创伤性的检查,而且只有当出血恰巧发生在对照剂注入和出血率大于0.5～1ml/分时,才可显示阳性结果。 1984年6月～1987年5月,作者对3年中直肠大出血的病人进行了研究,所有病人均采用体内锝一 Preoperative determination of gastrointestinal bleeding in patients with bleeding sites is still a clinical problem. The traditional barium examination, about 30% of patients can not locate its potential bleeding sites. Even if the lesion has been identified, but not sure it is the source of bleeding. Although the colonoscopy can be used to diagnose, due to a large number of bleeding resulting blurred vision is not practical. Selective angiography is a traumatic test and shows positive results only if bleeding happens to occur when the contrast medium is infused and the bleeding rate is greater than 0.5 to 1 ml / minute. June 1984 ~ May 1987, the author of 3 years of rectal bleeding in patients were studied, all patients were used in vivo technetium a