This part of IEC 61391 defines terms and specifies methods for measuring the maximum depth of penetration and the local dynamic range of real-time ultrasound B-MODE scanners. The types of transducers used with these scanners include: – mechanical probes; – electronic phased arrays; – linear arrays; – curved arrays; – two-dimensional arrays; – three-dimensional scanning probes based on a combination of the above types. All scanners considered are based on pulse-echo techniques. The test methodology is applicable for transducers operating in the 1 MHz to 15 MHz frequency range operating both in fundamental mode and in harmonic modes that extend to 15 MHz. However, testing of harmonic modes above 15 MHz is not covered by this standard. NOTE Phantom manufacturers are encouraged to extend the frequency range to which phantoms are specified to enable tests of systems operating at fundamental and harmonic frequencies above 15 MHz.