Kyoto Kagaku MRI QA Phantom PH-31 User manual

MRIQAPhantom
PH-31
●Resources・・・・・・・・・・・・・
P.1
P.4
P.6
● Beforebeginning
Productcontentsandwarning・・・・・・・
Howtousethephantom・・・・・・・・ P.
●Preparation
How to fill with MRI solution・・・・・・・・・
How to fill with MRI solution - Warning
2-P.3
P.8-P.9
Instruction
Manual
Contents
Uniformity section ・・・・・・・・・・・・・
●How to use
Contrast section ・・・・・・・・・・・・・・
Quadrature setting section ・・・・・・・・・
Slice thickness section ・・・・・・・・・・
Spatial resolution section ・・・・・・・・・
Image distortion and static magnetic
uniformity section ・・・・・・・・・・・・・
P.12.-P.15
P.5
P.11
P.10
P.7

1
1
1
1
1
1
1
5
１
a
b
c
d
e
f
g
h
Beforebeginning Productcontentsandwarning
Productcontents
Beforeyourfirstuse,ensurethatyourproductincludesallcomponentslistedbelow.
Please handle with care.The phantom is made
of hard resinous material; the phantom can be
damaged if dropped or hit by a hard object.
Phantom unit A
Phantom unit B
Liquid paraffin (suitable for 3T)
MRI contrast solution (nickel
dichloride)
*5 levels of concentration, 50mL per bottle (5,
10, 15, 20, 25 millimole)
Petroleum jelly
Screwdriver
Dropper
Funnel
Extra screws
Instruction manual
●Please clean the phantom with water or
pH neutral detergent. Please do not use organic
detergent such as thinner.
●
Please do not store in high temperatures,
high humidity or in direct sunlight. It may lead
to deformation or damages.
●Please do not write with a pen. Writing directly
on the phantom with felt-tip pen or permanent
marker will not wash off.
●
Warning
ab
c
d
e
ｆ
ｇ
h
i
i4

２
Beforebeginning Howtousethephantom
Howtousethephantom
Acrylicmaterials,Outerdiameter220mm
140
φ220
Contrastsection
Samplebottle(12.8mL)-7unitstotal
Uniformsection Quadra-settingsection
PhantomunitA Liquidcapacity3180mL
Structuraldesign
φ30
φ5

３
140
φ220
Distortedimagesection
Uniformstaticmagneticfield
-10to69units
Slicesection
Spaceresolutionsection
φ0.5
φ0.75
φ1.0
φ2.0
Beforebeginning Howtousethephantom
Howtousethephantom
Acrylicmaterials,Outerdiameter220mm
PhantomunitB Liquidcapacity3300mL
Structuraldesign

4
1. In order to avoid liquid leaks due to temperature changes, the phantom is not totally filled up with the
solution at the time of delivery. First, remove one of the two plastic caps for the main unit of the phantom. Then
insert the funnel into the hole to fill up the phantom pouring the paraffin solution (c) into the unit.
2.Fill up the rest of the unit using the dropper
slowly without leaving air bubbles inside. Then
close the unit again placing back the plastic cap.
T1 and T2 values are heavily dependent on temperature change; please take
extreme care in maintaining a consistent temperature when the phantom is in use.
Leave the phantom with the contrast solution in room temperature for over 24
hours to retain a consistent temperature for the product. Raw materials used to
manufacuture the provided nickel dichloride solution is manufactured in 23 degrees
Celcius with relative humidity of 40%.
2Warning
1
Preparation HowtofillwithMRIsolution
Warning
HowtofillwithMRIsolution
※In order to avoid liquid leaks due to temperature
changes, take out the paraffin solution and return
it to its original liquid container (c) after using the
phantom.

5
１
How to Use
Setting
２Contrast Section
Setting Contrast
Section
Solution holers
- First fill up the main body of the phantom with the liquid paraffin and close the
cap tightly.
- The phantom shall be centered in the RF receiver coil, with its flat sides parallel
to the designated scanning section.
- Use the lines on the wall of the phantom as landmarks for positioning.
The section has seven holders to set the sample bottles. Fill the bottles with
NiCl₂ solution with different concentration (5 variations of solution are
included in the set) to evaluate the contrast.
Further study is possible by adding optional samples.
Select the most appropriate setting by adjusting the Pulse Parameter and the
Image sequence.
7 Solution holders

6
３
Uniformity Section
Uniformity Section
Section
for
Uniformity
How to Use
-Signal to Noise Ratio (S/N)
Set the slide thickness at 10mm or below, and scan the section with the spin echo
method at 3T≦ TR≦ 5T1 conditions.
Execute the first scan. Position the ROI on the center of the volume………(R1)
Immediately after the first scan, repeat the scan with the same settings to acquire the
second data…………………………(R2)
Subtract (R2) from (R1) to obtain the difference of the images, and set the ROI in the
same place as (R1)……(R3)
（R3)＝（R1)−(R2)
Measure the signal intensity S of the ROI (R1), the standard deviation SD of
(R3), and calculate the S/N＝ 2 x S / SD
NEMA defines Measurement Regions of Interest (MROI) as a centered regular
geometric area enclosing at least 75% of the image of the signal producing
volume of the phantom, while AAPM standards mention a minimum
dimension in the image plane of at least 10cm or 80% of the image field of
view, whichever is larger.
-Image Uniformity
Adjust the S/N at 80 or more by increasing the slide thickness, increasing the
number of image additions, or using an appropriate filter.
Examine the signal from each pixel in the 75% to 80% of the central area of
the image of the phantom.
Determine the maximum value as S MAX, and the minimum value as S MIN.
The image uniformity is calculated as follows:
After turning off all the coils for the magnetic
field gradient, place the phantom in the
center of the main magnet, and adjust the
radio-frequency (RF) to acquire the
maximum signal. (For more details contact
the system manufacturer)
-RF Uniformity
This section is for measurement of the signal to noise ratio (S/N), the image
uniformity, and the RF uniformity.

7
４
Quadrature Setting Section
Quadrature Setting Section
φ30mm
φ５ｍｍ
45degrees
How to Use
This section is used to detect irregularities in the quadrature setting.
The section consists of a disc with a hole of 30mm diameter and 4 small
marker holes which line across the center of the disc perpendicularly to the
line from the 30mm hole.
When scanning the X-Y side, the phantom shall be placed so that the line
that connects the maker holes makes 45 degrees to the X axis. (Y axis)
Then, using the matrix method, scan the section two times or more with a
slice thickness of 10mm and the maximum matrix number. Use the image
sequence and the pulse parameter on the same conditions as used in the
common clinical settings.
Visually interpret the obtained images. In case that any irregularities of the
quadrature setting arise, the Ø 30mm hole will appear as a ghost artifact in a
symmetric position from the line formed by the marker holes.

8
５
Slice Thickness Section
Slice Thickness Section
L1=T/tan(15°＋α) ……………（１）
L2=T/tan(15°−α) ……………（２）
L1−L2
L1＋L2= =
=
tan(15°＋α)−tan(15°−α)
tan(15°＋α)＋tan(15°−α)
sin{(15°＋α)−(15°−α)}
sin{(15°＋α)＋(15°−α)}
sin2α
sin30°
……………（3）
How to Use
The two wedge shaped planks in this section are to measure a slice thicknesses of
10mm or less. Both planks are of 15 degrees inclination angle and 20mm thickness.
Scan the section with the maximum matrix number, in the conditions so that the TR
represents more than three times T1.
Using the multi-slice method, make the measurements on an image taken from the
center.
In the image, planks appear as black squares. Number them as first and second.
Place the ROI at the center, along the central line of the first plank, and calculate
the signal intensity of each pixel In.
n: pixel number
Obtain the slice profile by plotting the values of Dn obtained through the above
formula along the pixel distribution.
Calculate the FWHM (full width at half maximum) of the earned slice profile (L1). In
this case FWHM indicates the length of the line connecting the two points in which
Dn is the half of the maximum value of change.
Repeat the same procedure with the second plank to calculate L2.
When L1 is equal to L2, the calculation for the slice thickness T is: T=L1・tan15゜
However, L1 and L2 usually vary because of measurement errors due to the
rotation of the X, Y or Z axis during the setting of the phantom, or during the
setting of the slice section.
Therefore, the below correction is necessary:
Assuming that L1〈 L2 due to a rotation of the angle α around the Y axis, the angle
made up by the first plank and the slice side is:
15゜+ α
The angle made up by the second plank and the slice side is:
15゜－ α
The slice thickness T is calculated by using the values of L1,L2 and the above
mentioned rotation error α.
By substituting the α calculated by (3) in the formula (1) or (2) it is possible
to calculate the right slice thickness T.
In: signal pixel intensity of n pixel