The physiological monitoring sub-system includes video monitoring of an animal with real-time movement detection, ECG and breathing detection, and temperature stabilization. A colour TV-camera (5 Mp in SKYSCAN 1278) is mounted above the animal bed and equipped with white LED illumination to produce a real-time image of the animal during the scan. The software analyses the video stream from a user selected area of the image, which the operator can position on a part of the animal body where breathing movement is visible. These movements are converted into a movement waveform to provide breathing timemarks for time-resolved micro-CT reconstruction.
The face mask on the animal bed is connected to an air/gas flow sensor for direct breathing detection. The ECG electrodes in the animal cassette are connected to a sensitive ECG amplifier. Both breathing and ECG signals are digitized, sent to computer and displayed as real-time profiles on-screen. An operator can select individual gain and threshold for each signal to optimize generation of timemarks.
The monitoring also includes temperature stabilization by heated airflow, which maintains the scanned animal at a selected temperature, to prevent cooling of the animal under anaesthesia.