【摘 要】 14C 尿素呼气试验存在放射性；14C同位素发出β射线，半衰期为5730年；核医学设施条件下开展；造成生殖损害，进而导致患者和医务人员体内可能的累积效应。

The carbon-14 (radioactive) UBT is available at some university health centres but must be performed in a nuclear medicine facility. With the carbon-13 (nonradioactive, stable) UBT, breath samples can be collected anywhere (e.g., physician's office)