RTI Slit Camera User Manual
4707.001199#1.0B RTI Slit Cameara User’s Manual
2015-02-11
RTI
Slit Camera
User’s Manual – English – Version 1.0B
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1. Introduction
About this Manual
RTI Slit Camera User’s Manual 1.0B
Table of Contents
1. Introduction ........................................................................................3
1.1. About this Manual .................................................................................. 3
1.2. Introduction to the Slit Camera ............................................................... 3
2. Description of the RTI Slit Camera ....................................................4
2.1. Setting Up the Slit Camera for the First Time .......................................... 5
2.2. Hardware and Specifications .................................................................. 5
2.2.1. Slit Camera ................................................................................... 5
2.2.2. Dimensions ................................................................................... 5
2.3. Standards and Compliances .................................................................. 6
2.3.1. Waste Electrical and Electronic Equipment (WEEE) ....................... 6
3. Theory of Focal Spot Reproduction ..................................................7
3.1. Theory................................................................................................... 7
3.2. Why measure the focal spot? ................................................................. 8
4. X-Ray Tube Focal Spot Measurements ........................................... 11
4.1. Purpose .............................................................................................. 11
4.1.1. Equipment Recommended for Focal Spot Measurements ............. 11
4.2. Focal Spot Test Stand Alignment ......................................................... 11
4.3. Slit Measurement Using Film and Magnifier Lens .................................. 12
4.4. Slit Measurement Using Digital Image .................................................. 13
4.4.1. Evaluation using ImageJ .............................................................. 13
5. Word List .......................................................................................... 16
6. Appendix A ....................................................................................... 19
6.1. A.1. Nominal Focal Spot Size - IEC 60336 ............................................ 19
7. Index ................................................................................................. 21
1. Introduction
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About this Manual
1.0B RTI Slit Camera User’s Manual
1. Introduction
1.1. About this Manual
This manual is divided into a few main parts.
1. A general description of the Slit Camera.
2. Descriptions and hints on performing measurements.
3. Troubleshooting tip, and FAQ.
Typographical Rules
Terms in bold face are references to texts on screenshots, like buttons and texts, and
menu items. Other terms are italicized.
1.2. Introduction to the Slit Camera
Congratulations to your purchase of the Slit Camera from RTI. You have now in your
hand a quality tool for focal spot size evaluation. It has been carefully designed to meet
the needs of modern X-ray systems.
If you have questions, comments, or feel that some functionality is missing, you are
welcome to contact us at RTI Electronics at sales@rti.se. You can of course also call
(see notice section for details).
The Slit Camera does not come with any evaluation tool.
RTI recommends digitalizing the slit image and using an image
evaluation tool to measure in the image. An example of such software is
ImageJ, http://imagej.nih.gov/ij/
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2. Description of the RTI Slit Camera
Introduction to the Slit Camera
RTI Slit Camera User’s Manual 1.0B
2. Description of the RTI Slit Camera
The RTI Slit Camera for x-ray focal spot measurement comes with a stand with an
adjustable rod. Optionally also a tilting device is available.
Figure 2-1 Slit Camera with (left) and without (right) the optional tilting device.
The Slit Camera can be rotated 90 degrees in the Slit Camera holder. See figure 2-2
below. The 90 degree rotation simplifies the measurement of length and width
measurements of the focal spot since the slit only have to be aligned once.
Figure 2-2 The Slit Camera can be rotated by means of 90 degrees.
The optional tilting device enables measurements where the reference position is not
orthogonal to the image plane, which is normal in mammography. See figure 2-3 below.
2. Description of the RTI Slit Camera
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Setting Up the Slit Camera for the First Time
1.0B RTI Slit Camera User’s Manual
Figure 2-3 The optional Tilting Device is ideal for use in mammography where the
reference position normally is not orthogonal to the breast support.
2.1. Setting Up the Slit Camera for the First Time
Before you use your Slit Camera for the first time, mount the Slit Camera and the stand
to make sure that all mechanical parts fits together, and that no parts have been
damaged during transportation.
2.2. Hardware and Specifications
All specifications can be changed without prior notice. RTI assumes no responsibility
for any errors or consequential damages that may result from the misuse or
misinterpretation of any information contained in these specifications.
2.2.1. Slit Camera
Supporting standards IEC 60336
Tube focal spot types Radiographic, CT, Mammographic, Dental
kV range 18 - 150 kV
Enlargement factor E 0.8 - 5
E = n/m, where:
n = slit to detector distance
m = slit to focal spot distance
Measurement range 0.1 - 5 mm
2.2.2. Dimensions
Slit holder size 97 x 34 x 6 mm
Slit dimensions 10 µm (as defined by IEC 60336)
Slit material Tungsten (W, 99.9 %)
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2. Description of the RTI Slit Camera
Standards and Compliances
RTI Slit Camera User’s Manual 1.0B
2.3. Standards and Compliances
Hereafter you can find declarations of conformity, as well as documents describing the
intended use of the Slit Camera.
2.3.1. Waste Electrical and Electronic Equipment (WEEE)
The European Union Directive 2002/96/EC on Waste from Electrical and Electronic
Equipment (WEEE) places an obligation on manufacturers, distributors, and retailers to
take back electronics products at the end of their useful life.
The WEEE directive covers all RTI products being sold into the European Union (EU)
as of August 13, 2005. Manufacturers, distributors, and retailers are obliged to finance
the cost of recovery from municipal collection points, reuse, and recycling of specified
percentages per the WEEE requirements.
Instructions for disposal of WEEE by Users in the European Union
The symbol, shown left, is marked on the product, which indicates that this
product must not be disposed of with other waste. Instead, it is the user's
responsibility to dispose of the user's waste equipmen
t by handing it over to
a designated collection point for the recycling of waste electrical and
electronic equipment. The separate collection and recycling of waste
equipment at the time of disposal will help to conserve natural resources
and ensure that it is recycled in a manner that protects human health and
the environment. For more information about where you can drop off your
waste equipment for recycling, please contact your local distributor from
whom you purchased the product.
3. Theory of Focal Spot Reproduction
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Theory
1.0B RTI Slit Camera User’s Manual
3. Theory of Focal Spot Reproduction
3.1. Theory
The focal spot is being reproduced (depicted) according to the IEC 60336 [Reference
1], standard through a 10 µm wide slit, and then registered with an image receptor (not
included in the RTI Slit Camera). This is described in figure 1 below. The reproduction
is a one-dimensional “picture” of the focal spot in one direction and a perpendicular
measurement has to be done to get the characteristics of the focal spot in both length
and width directions.
Figure 3–1 Focal spot reproduction. The grey part to the right shows an image taken
with a film in the picture plane. Note the lighter part in the middle indicating the dip
between the two peaks.
As shown in Figure 3–1, you get a measured width of the focal spot, fm. This measured
focal spot is an enlargement of the true focal spot on the anode, fw, magnified by the
factor E, which is n divided by m.
The distance from the true focal spot to the slit is m, and n is the distance from the slit
to the image receptor. The slit width is denoted by s. The true focal spot width can thus
be calculated as:
fw =
m
n
fm (Eq. 3.1)
where
represents the penumbra from the slit.
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