Nuclear Associates 07-645
Fluoro-Test™ Tool
March 2005
Manual No. 07-645-1 Rev. 2
©2003, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies
Users Manual
Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
www.flukebiomedical.com/rms
Table of Contents
Section 1: Instructions ................................................................................................ 1-1
1.1 Description................................................................................................... 1-1
1.2 Instructions for Use...................................................................................... 1-1
1.2.1 Example One ............................................................................................... 1-2
1.2.2 Example Two ............................................................................................... 1-2
1.2.3 Example Three ............................................................................................ 1-2
1.3 Discussion ................................................................................................... 1-2
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Instructions
Description
1
Section 1
Instructions
1.1 Description
The Fluoro-Test Tool™ is a fluoroscopic contrast resolution test tool that is based on the work of Wagner,
Barnes and Wu [1]. The test tool consists of two 6" x 6", 6.1 mm (¼") thick aluminum plates with each
plate containing an array of 1.1 cm targets of varying contrast. Also included in the Fluoro-Test kit are
three 6" x 6", 1 mm thick copper sheets. The test tool is designed to be used with the copper attenuator
sheets positioned close to the source (i.e., at table top) and the aluminum test plate located close to the
image intensifier input as illustrated in Figure 1-1. With 2 mm of copper attenuator in the beam and a
fluoroscopic x-ray tube potential of 80 kVp, the contrast of the targets in Plates A and B are given in
Figure 1-2A and 1-2B, respectively. Each plate has three rows of three targets with a moderately large
(≅3%) contrast increment between adjacent targets in the same row. The outer two rows have increasing
target contrast increments while the middle row is offset and has decreasing increments. At 80 kVp with 2
mm of Cu attenuator the targets range in contrast from ≅1% to ≅9% in Plate A (integer phantom) and from
≅0.5% to ≅8.5% in Plate B (half-integer phantom).
1.2 Instructions for Use
1. For conventional geometry fluoroscopic units (under-table x-ray tube/over-table imaging chain)
place two copper sheets (i.e., a total copper thickness of 2.0 mm) on the tabletop and aluminum
Test Plate A directly beneath the image intensifier input phosphor or spot film device cover as
shown in Figure 1-1. The spot film device/imaging chain should be positioned 12" to 16" above the
tabletop. If the fluoroscopic unit has an over table x-ray tube/under table imaging chain, place the
copper sheets directly beneath the collimator and Test Plate A on the table top or on the image
intensifier. In either geometry the copper sheets and Test Plate should be centered in the
fluoroscopic field-of-view (FOV).
2. If the image intensifier has different FOVs, select the 22 cm (9") FOV or the FOV that is closest to
22 cm.
3. Note the fluoroscopic kVp. Scan the image and note the number of targets that can be seen in each
row.
4. Replace Test Plate A with Test Plate B and repeat step 3. In general the fluoroscopic kVp will
remain the same.
5. The target contrast visibility threshold or low contrast resolution can be ascertained by determining
the lowest contrast target that is seen in the two plates. The contrast of targets on Plate B are
slightly less (≅0.5%) than the targets in Plate A and, if the same number of targets are seen on
each plate, the contrast resolution is the lowest contrast target seen in the image of Plate B. If more
targets are seen in the image of Plate A, the contrast resolution is the lowest contrast target seen in
Plate A. The contrast of the targets for a beam hardened by 2.0 mm of copper are given in Table 1
as a function of fluoroscopic x-ray tube potential.
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Operators Manual
1.2.1 Example One
Image Readings
The copper sheets (a total of 2.0 mm of Cu) and Test Plate A are positioned as depicted in Figure 1-1.
The fluoroscopic tube potential stabilizes at 80 kVp. In the fluoroscopic image of Test Plate A two targets
are seen in Row 1, two targets are seen in Row 2 and three targets are seen in Row 3, Test Plate A is
removed and replaced with Test Plate B. In the fluoroscopic image of Test Plate B two targets are seen in
Row 1, two targets are seen in Row 2 and two targets are seen in Row 3.
Interpretation of Readings
If the fluoroscopic x-ray tube potential stabilizes at 80 kVp, the contrast of the targets are given by their
target or hole number (see Figure 1-2 and Table 1-1). The lowest contrast target that is visualized is
target 3 in Row 3 of Test Plate A and the low contrast resolution of the fluoroscopic unit is 3.0%.
1.2.2 Example Two
Image Readings
The copper sheets (a total of 2.0 mm of Cu) and Test Plate A are positioned as depicted in Figure 1-1.
The fluoroscopic tube potential stabilizes at 90 kVp. In the fluoroscopic image of Test Plate A two targets
are seen in Row 1, two targets are seen in Row 2 and two targets are seen in Row 3. Test Plate A is
removed and replaced with Test Plate B. In the fluoroscopic image of Test Plate B two targets are seen in
Row 1, two targets are seen in Row 2 and two targets are seen in Row 3.
Interpretation of Readings
When the number of targets seen on both plates are the same, the lowest contrast target seen is on Plate
B. In this example it is Target 3.5 in Row 1. The contrast of Target 3.5 at 90 kVp and 2.0 mm of copper
beam attenuator is given in Table 1 and is 3.2%.
1.2.3 Example Three
Image Readings
The copper sheets (a total of 2.0 mm of Cu) and Test Plate A are positioned as depicted in Figure 1-1.
The fluoroscopic tube potential stabilizes at 65 kVp. In the fluoroscopic image of Test Plate A two targets
are seen in Row 1, two targets are seen in Row 2 and three targets are seen in Row 3. Test Plate A is
removed and replaced with Test Plate B. In the fluoroscopic image of Test Plate B two targets are seen in
Row 1, two targets are seen in Row 2 and three targets are seen in Row 3.
Interpretation of Readings
The lowest contrast target seen is Target 2.5 in Row 3 of Plate B. The contrast of this target at 65 kVp
can be determined by interpolating between the 60 and 70 kVp target contrast values in Table 1. The
contrast of Target 2.5 at 60 kVp is 3.28%. At 70 kVp the target contrast is 2.79%. Interpolating between
the two values one obtains a contrast resolution of 3.0%.
1-2
Instructions
Discussion
1
1.3 Discussion
The test object is compact and the dimensions of the target plates are consistent with the commonly used
Center of Devices and Radiological Health test stand. The target arrangement is designed to reduce the
ambiguity and difficulty associated with employing a sequential array of targets with small differences in
contrast between adjacent targets. With the Fluoro-Test target plates the observer focuses on a subset of
three targets at a given time. In each subset or row, large differences (≅3%) are present between
adjacent targets and it is easy to decide if a target is visualized or not. As noted above the threshold
contrast for a plate is the lowest of the values observed for the three rows of targets, and a threshold
contrast resolution precision of 0.5% is obtained by the sequential use of the two plates. Of practical
importance is that the effect of fluoroscopic tube potential can be taken into account employing Table 1
which lists the percent contrast for the Fluoro-Test targets with 2 mm of Cu attenuator as a function of
tube potential from 50 to 130 kVp in 10 kV increments. If in the event that a 1 mm or 3 mm Cu attenuator
is employed rather than a 2 mm attenuator, the percent contrast of the test plate targets for these
thicknesses of Cu attenuators are listed in Tables 2 and 3. If one needs the contrast values of the targets
for a 1.2 or 2.4 mm Cu attenuator, the two decimal place accuracy of the Tables 1-3 permit one to
develop an interpolated table for the desired in-between copper thickness.
The Fluoro-Test is designed to yield a quantitative assessment of fluoroscopic threshold contrast
resolution. This index along with limiting high contrast resolution and image intensifier input phosphor
exposure rate should be measured during acceptance testing and routine quality control audits. High
contrast spatial resolution and image intensifier input phosphor exposure rate should be measured for
each image intensifier mode i.e., 9", 6" and 4.5". However, it is only necessary to determine threshold
contrast resolution in the 9" image intensifier mode. If one has a 12", 9", and 6" image intensifier,
threshold contrast should also be assessed in the 9" mode.
Factors that affect fluoroscopic contrast resolution are the quality of the imaging chain, the image
intensifier input phosphor exposure rate and, on fluoroscopic units equipped with digital image processing
and averaging, the degree of digital averaging. For a given image intensifier input phosphor exposure
rate, the better the imaging chain, the lower the contrast resolution. If the input phosphor exposure rate is
increased, the fluoroscopic image contrast resolution will decrease and therefore improve. Likewise, if
digital averaging is activated, contrast resolution will decrease and therefore improve.
For a typical image intensifier input phosphor exposure rate (3.6 mR/min with the grid out and 2.0 mm of
copper in the beam), the low contrast resolution of a reasonable imaging chain will range from 3 to 4%. A
good imaging chain will achieve a low contrast resolution of less than 3.0% and the low contrast
resolution of a poor imaging chain will be as high as 5 or 6%. Often on a poor imaging chain, the input
phosphor exposure rate is increased to achieve acceptable low contrast resolution and image quality. For
additional information and further discussion, the user is referred to the paper by Wagner, Barnes and Wu
[1], It is anticipated that tracking the threshold contrast resolution of a fluoroscopic imaging chain following
acceptance testing will allow one to quantify its performance over time and determine when adjustments
and maintenance need to be performed or when imaging chain components need to be replaced.
1. A.J. Wagner, G.T. Barnes and X. Wu, "Assessing fluoroscopic contrast resolution: A practical and
quantitative test tool," Med. Phys. 18, 894-899 (1991).
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Operators Manual
Table 1-1. Percent contrast for Fluoro-Test Threshold Contrast Resolution Plates with 2
mm Cu Attenuator
kVp
Hole
Number
0.5 0.84 0.66 0.56 0.50 0.46 0.43 0.41 0.39 0.38
1 1.67 1.31 1.11 1.00 0.92 0.87 0.82 0.79 0.76
1.5 2.51 1.97 1.67 1.50 1.39 1.30 1.24 1.18 1.14
2 3.34 2.62 2.23 2.00 1.85 1.74 1.65 1.58 1.52
2.5 4.18 3.28 2.79 2.50 2.31 2.17 2.06 1.97 1.90
3 5.01 3.94 3.34 3.00 2.77 2.60 2.47 2.37 2.28
3.5 5.85 4.59 3.90 3.50 3.23 3.04 2.88 2.76 2.66
4 6.68 5.25 4.46 4.00 3.70 3.47 3.30 3.16 3.03
4.5 7.52 5.90 5.01 4.50 4.16 3.91 3.71 3.55 3.41
5 8.35 6.56 5.57 5.00 4.62 4.34 4.12 3.95 3.79
5.5 9.19 7.22 6.13 5.50 5.08 4.77 4.53 4.34 4.17
6 10.02 7.87 6.69 6.00 5.54 5.21 4.94 4.74 4.55
6.5 10.86 8.53 7.24 6.50 6.01 5.64 5.36 5.13 4.93
7 11.69 9.18 7.80 7.00 6.47 6.08 5.77 5.53 5.31
7.5 12.53 9.84 8.36 7.50 6.93 6.51 6.18 5.92 5.69
8 13.36 10.50 8.92 8.00 7.39 6.94 6.59 6.31 6.07
8.5 14.20 11.15 9.47 8.50 7.86 7.38 7.01 6.71 6.45
9 15.04 11.81 10.03 9.00 8.32 7.81 7.42 7.10 6.83
50 60 70 80 90 100 110 120 130
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Instructions
Discussion
Table 1-2. Percent Contrast for Fluoro-Test Threshold Contrast Resolution Plates with1
mm Cu Attenuator.
kVp
Hole
Number
0.5 0.91 0.72 0.61 0.55 0.50 0.47 0.46 0.44 0.43
1 1.83 1.44 1.22 1.09 1.01 0.95 0.93 0.89 0.86
1.5 2.74 2.16 1.84 1.64 1.51 1.43 1.39 1.33 1.28
2 3.65 2.88 2.45 2.19 2.02 1.90 1.85 1.78 1.71
2.5 4.57 3.61 3.06 2.73 2.52 2.38 2.32 2.22 2.14
3 5.48 4.33 3.67 3.28 3.03 2.85 2.78 2.67 2.57
3.5 6.39 5.05 4.29 3.83 3.54 3.33 3.25 3.11 3.00
4 7.31 5.77 4.90 4.38 4.04 3.80 3.71 3.56 3.43
4.5 8.22 6.49 5.51 4.92 4.55 4.28 4.17 4.00 3.86
5 9.13 7.21 6.12 5.47 5.05 4.75 4.64 4.45 4.28
5.5 10.05 7.94 6.74 6.02 5.56 5.23 5.10 4.90 4.71
6 10.96 8.66 7.35 6.57 6.06 5.70 5.57 5.34 5.14
6.5 11.88 9.38 7.96 7.11 6.57 6.18 6.03 5.79 5.57
7 12.79 10.10 8.58 7.66 7.07 6.66 6.50 6.23 6.00
7.5 13.71 10.82 9.19 8.21 7.58 7.13 6.96 6.68 6.43
8 14.62 11.55 9.80 8.76 8.09 7.61 7.42 7.12 6.86
8.5 15.54 12.27 10.42 9.30 8.59 8.08 7.89 7.57 7.29
9 16.45 12.99 11.03 9.85 9.10 8.56 8.35 8.02 7.72
50 60 70 80 90 100 110 120 130
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Nuclear Associates 07-645
Operators Manual
Table 1-3 Percent Contrast for Fluoro-Test Threshold Contrast Resolution Plates with3
mm Cu Attenuator.
kVp
Hole
Number
0.5 0.80 0.63 0.53 0.48 0.44 0.41 0.39 0.37 0.36
1 1.60 1.25 1.06 0.96 0.88 0.82 0.78 0.75 0.72
1.5 2.40 1.88 1.60 1.43 1.32 1.24 1.17 1.12 1.08
2 3.20 2.51 2.13 1.91 1.76 1.65 1.56 1.50 1.44
2.5 4.00 3.13 2.66 2.39 2.20 2.06 1.95 1.87 1.80
3 4.80 3.76 3.19 2.87 2.64 2.47 2.34 2.24 2.16
3.5 5.60 4.39 3.72 3.34 3.08 2.89 2.73 2.62 2.52
4 6.40 5.01 4.25 3.82 3.52 3.30 3.13 2.99 2.87
4.5 7.20 5.64 4.79 4.30 3.96 3.71 3.52 3.37 3.23
5 8.00 6.27 5.32 4.77 4.40 4.12 3.91 3.74 3.59
5.5 8.80 6.89 5.85 5.25 4.84 4.53 4.30 4.11 3.95
6 9.60 7.52 6.38 5.73 5.28 4.95 4.69 4.49 4.31
6.5 10.40 8.14 6.91 6.21 5.72 5.36 5.08 4.86 4.67
7 11.20 8.77 7.44 6.68 6.16 5.77 5.47 5.23 5.03
7.5 12.00 9.40 7.98 7.16 6.60 6.18 5.86 5.61 5.39
8 12.80 10.02 8.51 7.64 7.04 6.60 6.25 5.98 5.75
8.5 13.60 10.65 9.04 8.12 7.48 7.01 6.64 6.36 6.11
9 14.40 11.28 9.57 8.59 7.92 7.42 7.03 6.73 6.47
50 60 70 80 90 100 110 120 130
1-6
Instructions
y
Discussion
12 – 16”
Image Intensifier
A1 Test Plate
Cu Attenuator
Table Top
Collimator
X-Ra
Tube
1
Figure 1- 1. Fluoro-Test Threshold Contrast Resolution Imaging Geometry.
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Operators Manual
a
Figure 1- 2A. Test object numbered to indicate calibrated contrast at 80 kVp for the Integer
Phantom.
1, 3 Lead Orientation Markers
A. Identification Marker.
b
Figure 1-2B. Test object numbered to indicate calibrated contrast at 80 kVp for the Half-Integer
Phantom.
1-8
Instructions
Discussion
1, 3 Lead Orientation Markers
B. Lead Identification Marker.
1
1-9
Fluke Biomedical
Radiation Management Services
6045 Cochran Road
Cleveland, Ohio 44139
440.498.2564
www.flukebiomedical.com/rms
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