His initial design in 1971, which was described in his application for a Dutch patent, consisted of only 20 crystals (each 4mm x 10mm).
The probe face was 66 mm long and 10 mm wide and produced 20 scan lines.
At the same time, but quite independently of this, numerous studies on fetal breathing movements, fetal behavior and neonatal cardiology were published ....... Chef, Maternit Reine-Astrid, Charleroi (Belgium), in the foreword to the Proceedings of the International Symposium on Real-time Ultrasound in Perinatal Medicine held in 1978 at Charleroi.
James Griffith and Walter Henry produced a mechanical oscillating real-time scanning apparatus in 1973 which was capable of producing clear 30 degree sectoral real-time images of good resolution.
The first real-time scanner, better known as fast B-scanners at that time, was developed by Walter Krause and Richard Soldner (with J Paetzold and and Otto Kresse) and manufactured as the Vidoson® by Siemens Medical Systems of Germany in 1965.
It operated at a frequency of 3.0 MHz sweeping at a frame rate of 150 frames/sec.
The axial resolution was 1.25 mm while the beam width at 6 cm was 10 mm.
The transducers operated at either 2.25 or 4.5 MHz, again with 20 crystals producing 20 scan lines.
The lateral resolution of this improved version at a dynamic range of 10d B was 3.7 mm at 6 cm and 6 mm at 10 cm depth.
It did not sell very well though because of its relatively primitive resolution and its inability to image abdominal structures adequately.