Calibrations Linear 2 0 SW

8/12/2019 Calibrations Linear 2 0 SW

1/24

By Nick Bublitz

Performing a Linear Scan Sensitivity/

Velocity/Wedge Delay Calibration-Longitudinal Wave PA Using SDHs at

Known Depths 2.0 SW


2/24

2

Calibrations-Required itemsCalibration block with 2 same size reflectors

at known depths- (Navships block with

SDHs)

Couplant-water works best

Guide to keep from skewing- use a ruler, set

the block on its side, or on IHC wedges can

screw down one sides carbide pins.


3/24

3

Velocity Calibration The velocity calibration will fine tune the velocity to

that of the calibration block. It will require two

reflectors of the same size at two different knowndepths.

In many cases the default material velocity and

wave type set by the operator in the group wizardis sufficient and this calibration can be skippedbecause wedge delay will adjust accordingly to

allow accurate measurements. If performed the velocity calibration should be

done before the wedge delay calibration.


4/24

4

Select Velocity CalibrationGo to the Wizard-

Calibration menu

Select Ultrasound and

Velocity

Start the wizard


5/24

5

Select A-Scan Put the probe on your

block over the first

reflector. Choose a VPA near the

middle of your probe.

Adjust range as needed toensure you will see the 2

reflectors you have

chosen.


6/24

6

Set Depth 1 and 2 Select depth from echo

type

Set depth 1 and depth

2 to your reflector

depths.


7/24

7

Set Gate A on Depth 1 Peak the reflector at

the chosen VPA.

Adjust the gate to

encompass the

reflector.Get position.


8/24


9/24

9

Accept or Restart View the velocity

determination

If it is sensible accept

the calibration, if not

restart.


10/24

10

Wedge Delay-Depth ReflectorWedge Delay will enter compensation for

the travel of the beams through the wedge

medium and account for the various exit

points or wedge wear.

Wedge delay needs only 1 distinct reflector-a known depth reflector will be used here.

After wedge calibrations, accuratemeasurements can be taken.


11/24

11

Wedge Delay Calibration-Depth Enter the calibration

menu

Select Ultrasound and

Wedge Delay-Start

Select depth and input

depth to the reflector

and a tolerance


12/24

12

Set Section

Decide if you want to

calibrate the whole

angular sweep orbreak it up into

separate calibrations-

for most setups with a

good calibration block

you can calibrate the

whole sweep. Hit Next


13/24

13

Set Gate A on Depth A

Put the probe on the block so

you can see the chosen

depth reflector.Adjust the gate

start/width/threshold to

encompass the reflector.Move the probe forward

and backwards to ensure

gate is encompassing

reflector through all angles

and there are no other

reflectors that will affect

calibration.


14/24

14

Calibrate and Accept

Move the probe forwardand backward applyingeven pressure andavoiding skewing right orleft.

Move in both directions

until the green line is builtacross the whole angularrange. Adjust gain asneeded.

Hit calibrate.


15/24

15

Accept or Restart

After hitting calibrate-

rerun the probe

through the angularrange verifying you are

within the set

tolerance.

Accept or Restart.


16/24

16

Sensitivity Calibrations

Sensitivity calibrations equalize the

sensitivity (amplitude response) from a

given reflector through all the VPAs

(beams).

This will insure no matter what VPA thereflector is seen with the % FSH is the same

for rejection or detection purposes as wellas for the amplitude based color coded

imaging selections.


17/24

17

Getting Started

Choose a SDH and

couple your probe

above it Use a guide system to

keep the probe from

skewing side to side.


18/24

18

Sensitivity Calibration

Enter Calibration menu

and select Sensitivity

Choose a referencescreen height to

equalize sensitivity to

(80% FSH) and atolerance


19/24

19

Set Section

Choose whether to

calibrate the whole

angular sweep in onestep or break it up into

separate calibrations-

if your calibration blockhas adequate spacing

between SDHs you

can usually do the

whole range.


20/24

20

Set Gate A on Echo ASet the gate to encompass the

SDH reflection. Adjust the

start/width/threshold of the gate.

Move the probe forward and

backward to ensure the gate

covers the reflector through allthe angles and is not on any

other reflectors that may inhibit

the calibration


21/24

21

Set Compensation Gain

Allows you to adjustthe gain as needed to

ensure the reflector isseen properlythroughout all the

angles In most cases no

adjustment or an

adjustment of theoverall gain (if overreference level FSH%)

is needed.


22/24

22


Applying even pressure

and not skewing right or

left, move the probeforward and backwards to

build the green line as the

reflector is seen by the

angles.

Ensure the green line is

on-screen across the

whole screen-not to low orover the tolerance lines.


23/24

23


Press Calibrate

Verify the calibration

by repeating theforward and backwardmovement of the probe

The green line shouldfall within the definedtolerance lines across

all the angles.Accept or Recalibrate

as needed.


24/24

Documents

Calibrations Linear 2 0 SW