SENSOR MEASUREMENT AND EXPERIMENTAL CONTROL IN NUCLEAR-MAGNETIC-RESONANCE IMAGING

A dual purpose sensor acquisition and experimental control system whic h functions in the demanding environment of a nuclear magnetic resonan ce imaging (NMRI) spectrometer is described. The system ensures accura te sensor readings during imaging and protects sensitive electronic eq uipment from the effects of the intense radio frequency pulses and mag netic field gradient switches in NMRI. A homebuilt isolation network w as constructed with isolation transformers and optoisolators. A variet y of hardware and software methods are implemented to ensure accurate sensor data. The system also allows for the ready incorporation of ext ernal events into the NMRI pulse sequence. LabVIEW(TM), a graphical pr ogramming environment, is the heart of our acquisition/control system. LabVIEW's graphical interface and modular design enables flexible pro grams to be constructed which are easily understood and modified by th e user. Applications of the system, monitoring photopolymerization and controlling ultrasonic cavitation in conjunction with NMRI, are outli ned. (C) 1996 American Institute of Physics.