Human solid-phase gastric-emptying measurement by AMS using 14C tracer

Determining solid-phase gastric emptying (GE) in a human being is an important application in clinical practice as it can provide valuable information for the diagnosis of related digestive diseases. Currently, ^99mTc gastric scintigraphy is considered as the gold standard for measuring GE. However, this method suffers from clinical drawback, such as radiation exposure. This study focuses on identifying alternative methods for GE measurement. Carbon-14 accelerator mass spectrometry (AMS) is a useful tool for biomedical projects due to its inherently high sensitivity and dynamic range, low dose and sample size requirements, and relatively short measurement time. However, it has not yet been implemented in GE tests. In this work, ¹⁴C AMS methodology was developed for breath samples. Measurements were conducted on a compact, single-stage AMS device at China Institute of Atomic Energy (CIAE). To investigate GE, micro-doses of ¹⁴C-octanoic acid, ¹³C-octanoic acid, and ^99mTc were marked along with tracers in the same test meal and subsequently ingested by volunteers. The ¹⁴C-octanoic acid breath test (¹⁴C-OBT) in combination with AMS showed better counting statistics than those obtained for the ¹³C-OBT measured using infrared spectroscopy. The results also demonstrate a considerably lower radiation dose than that in ^99mTc gastric scintigraphy. This work establishes an alternative method of ¹⁴C-AMS tracing to determine solid-phase GE in a human being, which could provide clinical technical support for a GE test and further expand the range of ¹⁴C-AMS applications in biomedicine.