1. Radiotracers are used in medical imaging to diagnose and monitor various conditions.
（放射性示踪剂被用于医学影像学中诊断和监测各种疾病。）

2. The radiotracer injected into the patient's bloodstream helps the doctors detect any abnormalities in the organs.
（注入患者体内血液的示追剂能够帮助医生检测出器官中的任何异常情况。）