Heart operations are already a major factor in extending life in many rich countries. Sophisticated X-ray diagnostic techniques such as CT scans make it possible to detect many cancers at a treatable stage.
但是如今，天平正在移动。在许多富有国家，心脏手术已经是延长生命的一个主要因素。像CT扫描那样先进的X光诊断技术可以在可治疗阶段检查出许多癌症。