[Diagnosis and quantiation of left to right shunts using radioisotopes]

After intravenous injection of 99mTcO-4 into the femoral vein the count-rate vs. time curve of a lung field is recorded and analysed (Ohio Nuclear Camera ON 110, pdp 11 computer GAMMA 11, hp 5407 computer). Using a modified gamma function area-ratio technique, the size of the left to right shunts is calculated and compared with cardiac catheter results (128 patients). The localisation of the left to right shunt (ASD or VSD) is possible, if the shunt size rises over 30%. The method may be an alternative to oximetry and conventional dilution techniques.