BS EN 61391-2:2010 pdf download

BS EN 61391-2:2010 pdf download.Ultrasonics — Pulse-echo scanners Part 2: Measurement of maximum depth of penetration and local dynamic range.
NOTE This parameter usually differs from the image display rate on the scanner monitor,
3.17
gain
ratio of the output to the input of a system, generally an amplifying system, usually expressed in decibels.
(IEC 61391-1:2006, definition 3.15J
NOTE The ratio applies for a constant and known acoustical system output
3.18
global dynamic range
ratio of the maximum to the minimum echo-signal amplitude, even with changes of settings, that a scanner can process without distortion of the output signal
3.19
harmonic Imaging
method of imaging in which ultrasound Is transmitted at a fundamental frequency and is detected at harmonic frequencies
NOTE Harnion.ca are generated by the propagation medium or by nonlinear reflectors, The resulting harmonic signal is displayed as an image or part of the image
3.20
local dynamic range
20 log10 of the ratio, of the minimum echo amplitude that yields the maximum grey level in the
digitized image to that of the echo that yields the lowest grey level at the same location in the
image and the same settings
Unit: dB
NOTE I For an 8.bit image memory, the maumum gray level in the digitized image will be 255.
NOTE 2 Scm. documents refer to local dynamic rang. as the range of echo signals required to vary th, display brightness from barely discernible to maximum hnghtness at a given location However, this international standard applies the nam, local dynamic range to th. diqrliz,d imag, data rather than data viewed on ti• image monitor. The name displayed acoustic dynamic range is the equivalent to local dynamic rang., but applied to data viewed on the image monitor
NOTE 3 This quantity is influenced by the grey ,cale (dynamic) transfer function associated with th, echo display
3.21
maximum depth of penetration
maximum distance In a tissue-mimicking phantom of specified properties for which the ratio of the digitized B-mode image data from background scatterers to the digitized B-mode image data displaying only electronic noise equals 1.4
Unit: m
NOTE The phantom and noise-only images are obtained using Identical system settings.
3.22
op.ratlng condition
any one of the possible particular control settings for a discrete or a combined operating mode
3.23
operating mode (discrete)
mode of operation of medical diagnostic ultrasonic equipment in which the purpose of the excitation of the ultrasonic transducer or ultrasonic transducer element group is to utilize only one diagnostic methodology
3.35
statistically independent images
images acquired from planes or directions such that the normalized cross-correlation of the underlying speckle pattern over a fixed region of interest, prior to any speckle reduction smoothing, is less than 0.2
NOTE Statistically independent image. are obtained from a phantom containing randomly distributed scatlerers by translating th. scanning plan., st..ring h. b.arn, .tc sich that th. und.rlying sp.ckI. pattern changes sut?icientiy to reduce the coirelation. Images whose speckle target cross-correlation is —0,2 or lower are sufficiently dc-correlated to Implement measurements in this standard
3.36
test object
device containing one or more groups of object configurations embedded in a tissue. mimicking material or another medium (see also phantom, tissue-mimicking phantom)
LIEC 61391-1:2006, definition 3.331
3.37
tissue-mImicking material
material In which the propagation velocity (speed of sound). reflection, scattering, and
attenuation propertIes are similar 10 those of soft tissue for ultrasound In the frequency range
1 MHz to 15MHz
IIEC 61391-1:2006, definition 3,36, modified]
3.38
tissue-mimicking phantom
Object comprising tissue-mimicking material
4 General requirement
The manufacturer’s specification shall allow comparison with the results obtained from the tests described in this standard.
5 Environmental conditions
All measurements shall be performed within the following ambient conditions:
– temperature. 23C ± 3C:
– relative humidity, 45 % to 75 %;
— atmospheric pressure. 86 kPa to 106 kPa.
Properties of ultrasound phantoms, such as speed of sound and attenuation coefficient, are known to vary with temperature. Consult the specifications published by the phantom manufacturer to determine whether the expected acoustic properties are maintained under the above environmental conditions.