Imaging Fluoropyrimidine-Based Cancer Chemotherapy Using 13C Hyperpolarised MR Technology

Yann Jamin¹, Simon P. Robinson¹, Martin O. Leach¹, Thomas R. Eykyn¹

The yeast cytosine deaminase (CD) is used in cancer chemotherapy to activate selectively the nontoxic prodrug 5-Fluorocytosine (5-FC) into the toxic antimetabolite 5-Fluorouracil (5-FU) in tumours. Employing Dynamic Nuclear Polarization (DNP) and ¹³C MRS, we demonstrate that both 5-FC and 5-FU are readily hyperpolarizable, demonstrate long T₁ (> 20s, at 11.7T) and a appreciable ¹³C chemical shift difference of ~ 5ppm. This results encourage further investigation on the use of hyperpolarized ¹³C MRS to monitor CD-mediated activation of 5-FU in vivo as well as other Fluoropyrimidine-based chemotherapy strategies.