In which decade did ultrasound first become capable of producing a two-dimensional image composed of grayscale dots?

• A. 1970s
• B. 1960s
• C. 1980s
• D. 1990s

Answer: (B)

The ability to produce a two-dimensional grayscale image in ultrasound came from the development of B-mode imaging, where echo strength is mapped into grayscale across multiple scan lines to form a cross-sectional picture. This shift from the one-dimensional A-mode display to a true 2D representation happened in the 1960s, as engineers and clinicians created scanners that could render a cross-section by compiling echoes from successive lines into a field of dots with varying brightness. The grayscale dots represent tissue echoes, so brighter dots indicate stronger reflections. Later decades brought real-time display enhancements and Doppler, but the first practical 2D grayscale imaging emerged in the 1960s.