PD IEC TS 62791:2022 - Page 3

Ultrasonics. Pulse-echo scanners. Low-echo sphere phantoms and method for performance testing of grey-scale medical ultrasound scanners applicable to a broad range of transducer types. | Status: Current

1 Scope This document, which is a Technical Specification, defines terms and specifies methods for quantifying detailed imaging performance of real-time, ultrasound B-mode scanners. Detail is assessed by imaging phantoms containing small, low-echo spherical targets in a tissue-mimicking background and analysing sphere detectability[3]. Specifications are given for phantom properties. In addition, procedures are described for acquiring images, conducting qualitative analysis of sphere detectability, and carrying out quantitative analysis by detecting sphere locations and computing their contrast-to-noise ratios. With appropriate choices in design, results can be applied, for example:

• • to assess the relative ability of scanner configurations (scanner make and model, scan head and console settings) to delineate the boundary of a tumour or identify specific features of tumours;
• • to choose scanner control settings, such as frequency or the number and location of transmit foci, which maximize spatial resolution;
• • to detect defects in probes causing enhanced sidelobes and spurious echoes.

The types of transducers used (see sections 7.6 and 10.7 of [1]) with these scanners include:

1. a) phased arrays,
2. b) linear arrays,
3. c) convex arrays,
4. d) mechanical sector scanners,
5. e) 3-D probes operating in 2-D imaging mode, and
6. f) 3-D probes operating in 3-D imaging mode for a limited number of sets of reconstructed 2-D images.

The test methodology is applicable for transducers operating in the 1 MHz to 23 MHz frequency range.