User's Manual

Appendix

7-16

Vscan Air

–

User Manual

Direction GP092020-1EN

Rev 08

Measurement accuracy

The following information is intended to provide guidance to the

user in determining the amount of variation or measurement

error that should be considered when performing clinical

measurements with this equipment. Error can be contributed by

equipment limitations and improper user technique. Be sure to

follow all measurement instructions and develop uniform

measurement techniques among all users to minimize the

potential operator error. Also, in order to detect possible

equipment malfunctions that could affect measurement

accuracy, a quality assurance (QA) plan should be established

for the equipment that includes routine accuracy checks with

tissue mimicking phantoms.

Please be advised that all distance related measurements

through tissue are dependent upon the propagation velocity of

sound within the tissue. The propagation velocity usually varies

with the type of tissue, but an average velocity for soft tissue is

assumed. This equipment is designed for, and the accuracy

statements listed on are based on, an assumed average velocity

of 1540 m/s..

Table 7-1: Measurement accuracy - Curved array (deep scanning) transducer

Measurement Unit Useful range Accuracy

Distance

Axial cm or mm 2mm-200mm ±1mm or ±3% whichever is

greater

Lateral cm or mm 4mm-100mm ±2mm or ±5% whichever is

greater

Circumference (ellipse) cm or mm 10mm-300mm ±5% or ±2mm whichever is

greater