Abstracts

RATIONALE: In a comparison of manual injection time with local automated injection time in patients undergoing ictal SPECT, we demonstrated a shorter injection time with the automated system (Epilepsia 39(12) 1350-1356, 1998). We also described a system designed to remotely initiating the automated injection in order to enhance convenience and reduce staffing needs. In this study we report the implementation of this system in hardware and software, for remotely controlling the automated injection from a video/EEG control room in an epilepsy monitoring unit.
METHODS: The injection system is the same as reported by us before. We developed software for controlling the pump through a serial port on a laptop. Four serial port lines from a socket in each of the patients[ssquote] rooms (running through the ceiling) may be connected to the laptop computer. Each serial port line may be connected to an automated IV pump at the patient[ssquote]s bedside. The software interface allows for entering the patient[ssquote]s data, the time (used for calibrating the radioligand dose), the dose to inject, and the volume to flush. Once the data is entered, the pump is ready for injection. When a seizure is recognized (by patient or staff) the inject button on the computer is pushed by a physician or epilepsy nurse. A safety message asks the operator if she/he is sure about injection, and if the response is yes, the ligand is automatically injected and followed by a flush. While waiting for a seizure to occur, the program calculates the dose to inject based on the exponential decay of radioactivity. So far four patients with unclear EEG localization and no focal lesion on MRI have been injected for both ictal and interictal SPECTs.
RESULTS: There were no safety problems with the injections so far: no radioactive spillage, no medical or other complications of the patients. The first injection was uninterpretable due to very low radioactivity caused by a mal functioning I.V. line. The next three patients had Left frontal, Right frontal and right anterior frontal epileptic foci respectively and the results helped planning the next presurgical step. The radioactivity counts at the time of submission of this abstract are suboptimal but interpretable. The problem was diagnosed as dead volume in the three way valve and we are currently fixing the problem.
CONCLUSIONS: The remote automated SPECT injection system has been implemented and safe so far. There are still minor technical problems which are being fixed, but the limitations of convenience, staffing needs and injection timing are addressed with the new system. Further investigation is needed to compare the efficacy of the new system with the manual injection.