F-19MRS による抗生剤の生体内挙動の測定 : 技術的基礎事項の検討

Abstract

Fluorine-19 (F-19) has a spin of 1/2 and has a 100% natural abundance. Thus, F-19 NMR allows direct observation of fluorinated drugs in the human body without background signal. A fluorinated antibiotic, Flomoxef Sodium (FMOX) can be observed noninvasively in the patient. Spectra were taken on a 1.5-T SIGNA MR imaging system. Shimming was performed on the tissue water resonance with the surface coil in the transmit/receive (t/r) mode. Spectra were taken with a surface coil in the t/r mode. A reference sample of 5-FU was mounted in the center of the coil. Nonselective 90°pulses were used. Preliminary sensitivity feasibility studies were carried out with 3-L plastic bottle as phantom with millimolar concentrations of FMOX. The relation between the transmitter power and signal level observed was measured using phantom experiments. And the sensitivity profile of the surface coil was also measured using phantom experiments. In clinical use, a bolus of 50mL of FMOX solution in a concentration of 2g/100mL FMOX was injected through an antecubital vein of the patient, followed by a infusion of 50mL of FMOX solution over approximately 8min. Aquisition of the spectra began as soon as the drug administration started and continued at 10min intervals for up to 1-hour thereafter. Serial spectra revealed the time course of the relative concentrations of FMOX in the target volume of each patient. This study demonstrates that it is possible to observe fluorine containing drugs in humans by F-19 NMR, as well as to directly estimate the time course of the drug's in vivo movement