Keywords: monitoring Substances: 5-Fluorouracil (GHASVSINZRGABV-UHFFFAOYSA-N) 5-Fluoro Cytosine (XRECTZIEBJDKEO-UHFFFAOYSA-N) 2-4-dimethylphenylformamide (JOFDPSBOUCXJCC-UHFFFAOYSA-N) 3-5-Diiodo-L-tyrosine (NYPYHUZRZVSYKL-ZETCQYMHSA-N)