Myocardial scintigraphy and radionuclide ventriculography at equilibrium are considered the best methods for the diagnostic of coronary disease and the assessment of myocardial performance and therapy follow-up.
Until now, the heavy equipment of conventional gamma-camera requires to immobilise the cardiac patient in a nuclear medicine department, usually for the assessment of heavy pathologies. This situation is unfavourable to address two clinical issues which would require light portable equipments :
the detection of transient ischemia, at the very early and silent stage of the coronary disease, in the apparently healthy and ambulatory patient,
the exploration of cardiac function at the first stage of myocardial infarction, in the intensive care unit, to improve both the prognostic, the therapy follow-up and the comprehensive study of the tissue injury and reperfusion.
Cadmium Telluride semiconductors have been chosen to conceive a new pixellised nuclear probe, because of their high sensitivity and high energy resolution, providing excellent spatial and contrast resolution for imaging. Such detectors can constitute the sensitive area of a light probe associated to a computer for data processing and image reconstruction in real time. This ensemble can be easily moved to the patient, either for ambulatory dynamic studies or for cardiac function assessment in an intensive care unit.
The industrial partners have defined their work tasks to build a light weight high resolution g-camera. Small size Cd Te detectors, 3 mm * 3 mm * 2 mm, allow their disposition in a 48 * 48 array (2304 independent pieces) in a 15 cm * 15 cm sensitive area designed to overlap the cardiac chest area. The array is divided in 12 blocks of 12 parallel modules inserted on a mother card. Each module is a card holding a line of 16 detectors connected to an integrated circuit for preamplification and signal shaping. The mother card is linked to a PC through a driving card and an acquisition card. A folded hexagonal hole lead collimator (1.13 mm holes, 0.16 mm septa, 24 mm high) achieves a FWMH better than 7 mm.
The physical characteristics and performance of the system will be evaluated in the Biophysics lab, and preliminary clinical applications will be tested in the nuclear medicine department of the same lab. The system will then be transferred to the nuclear medicine department of a cardiology hospital to undertake an comparative physiopathological study in real clinical situations.
Funding SchemeCSC - Cost-sharing contracts
OX11 0QX Chilton Didcot