Phantom Laboratory Catphan 503 Manual

Comprehensive ct performance measurements

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T h e

P h a

C a t p h a n ® 503 M a n u a l

WARRANTY

THE PHANTOM LABORATORY INCORPORATED ("Seller") warrants that this product

shall remain in good working order and free of all material defects for a period of one

(1) year following the date of purchase. If, prior to the expiration of the one (1) year

warranty period, the product becomes defective, Buyer shall return the product to the

Seller at:

y Truck

The Phantom Laboratory, Incorporated

2727 State Route 29

Greenwich, NY12834

Seller shall, at Seller's sole option, repair or replace the defective product. The Warranty

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CTP503

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Summary of Contents for Phantom Laboratory Catphan 503

Page 1: Warranty
Copyright © 2017 WARRANTY THE PHANTOM LABORATORY INCORPORATED (“Seller”) warrants that this product shall remain in good working order and free of all material defects for a period of one (1) year following the date of purchase. If, prior to the expiration of the one (1) year...
Page 2: Table Of Contents
T h e P h a n t o m L a b o r a t o r y Catphan® Manual Contents Warranty Introduction Initial phantom positioning Illustration of Catphan® 503 model Phantom position verification 7 Incremental phantom module positioning 8 Drawings in the manual 8 CTP404 module Patient alignment system check...
Page 4: Introduction
The Catphan® 503 phantom configuration has been selected by Elekta. This manual is intended to supplement the Elekta Procedures and Manuals by offering additional details regarding the use of the Catphan® phantom. The Phantom Laboratory and physicist, David J. Goodenough, Ph.D., are continually developing and researching new tests and modifications for the Catphan®...
Page 5: Initial Phantom Positioning
Initial phantom positioning The Catphan® phantom is positioned in the CT scanner by mounting it on the case. Place the phantom case on the gantry end of the patient table with the box hinges away from the gantry. It is best to place the box directly on the table and not on the table pads. Open the box, rotating the lid back 180°.
Page 6: Illustration Of Catphan® 503 Model
Because of beam divergence a physicist may develop specific alignment protocols. Single slice axial CT: the phantom can be centered on the CTP404 module and then after verifying the alignment, the table can be indexed to the center of the other modules. Spiral CT: the scanner can be aligned with the first module and then the phantom can be scanned in one sequence.
Page 7: Phantom Position Verification
Phantom position verification By evaluating a scan image of the CTP404 module the phantom’s position and alignment can be verified. The section contains 4 wire ramps which rise at 23° angles from the base to the top of the module. The schematic sketches below indicate how the ramp images change if the scan center is above or below the z axis center of the test module.
Page 8: Incremental Phantom Module Positioning
Incremental phantom module positioning The Catphan® 503 phantom is designed so all test sections can be located by precisely indexing the table from the center of module CTP404 to the center of the other test modules. The indexing distances from the center of the CTP404 module are listed below. Catphan®...
Page 9: Ctp404 Module
CTP404 Module with slice width, sensitometry and pixel size...
Page 10: Patient Alignment System Check
Patient alignment system check The laser, optical, and mechanical patient alignment system can be checked for accuracy. Align the white dots on the phantom housing with the alignment lights as discussed in Initial phantom positioning. The scanned image should show good alignment as discussed in Phantom position verification.
Page 11: Scan Slice Geometry (Slice Width)
Scan slice geometry (slice width) Section 1 has two pair of 23° wire ramps: one pair is oriented parallel to the x axis; the other pair to the y axis. These wire ramps are used to estimate slice width measurements and misalignment errors as previously discussed. The 23°...
Page 12: Scan Incrementation
Now that you have determined the half maximum CT number, you can measure the full width at half maximum of the ramp. Set the CT scanner level at the half maximum CT value and set your window width at 1. Measure the length of the wire image to determine the FWHM.
Page 13: Circular Symmetry
Circular symmetry of display system The circular phantom sections are used to test for circular symmetry of the CT image, including calibration of the CT display system. If an elliptical image is produced, the x-y balance of the image display system should be adjusted. Measuring spatial linearity in x and y axes.
Page 14: Ct Or Hounsfield Numbers By David Goodenough, Ph
CT or Hounsfield Numbers by David Goodenough, Ph.D. Users of CT systems are often surprised when the CT number of a given tissue or substance is different from what they expect from previous experience. These differences do not usually indicate problems of a given CT scanner, but more likely arise from the fact that CT numbers are not universal.
Page 15: Sensitometry (Ct Number Linearity)
, For standard material sensitometry inserts The Phantom Laboratory purchases a multiple year supply of material from a single batch. Samples of the purchased material are then measured to determine the actual specific gravity.
Page 16 An excel file with the linear attenuation coefficient µ [units cm -1 ] for the sensitometry materials can be downloaded from our web site. Contrast Scale (CS) is formally defined as CS = µ m (E) - µ w (E) CT m (E) –...
Page 17: Ctp528 High Resolution Module With 21 Line Pair Per Cm Gauge And Point Source
CTP528 High resolution module with 21 line pair per cm gauge and point source This section has a 1 through 21 line pair per centimeter high resolution test gauge and two impulse sources (beads) which are cast into a uniform material. The beads are positioned along the y axis 20mm above or below the phantom’s center and 2.5 and 10mm past the center of the gauge in the z direction.
Page 18: Use Of Automated Scanner Mtf Programs
The above illustration shows how by summing the columns (y axis) of numbers in the point spread function (PSF) the line spread function (LSF) for the x axis is obtained. The MTF curve results from the Fourier transform of the LSF data. Generally it is easiest to use automated software for this operation.
Page 19: Bead Point Source (Slice Sensitivity Profile)
Bead point source for slice sensitivity profile The bead in this module can be used to calculate the slice sensitivity profile (SSP). The above image illustrates how the bead will produce an ovoid object in a 3 dimensional reconstruction. The length of the object at the Full Width at Half Maximum signal indicates the SSP.
Page 20: 21 Line Pair Per Centimeter High Resolution Gauge
21 Line pair per centimeter high resolution gauge The 21 line pair/cm gauge has resolution tests for visual evaluation of high resolution ranging from 1 through 21 line pair/cm. The gauge accuracy is ± 0.5 line pair at the 21 line pair test and even better at lower line pair tests.
Page 21: Ctp486 Image Uniformity Module
CTP486 Image uniformity module The image uniformity module is cast from a uniform material. The material’s CT number is designed to be within 2% (20H) of water’s density at standard scanning protocols. The typically recorded CT numbers range from 5H to 18H. This module is used for measurements of spatial uniformity, mean CT number and noise value.
Page 22 Measure spatial uniformity by scanning the uniformity section. Observe the trends above and below the central mean value of a CT number profile for one or several rows or columns of pixels as shown above. Select a profile which runs from one side of the uniformity module to the opposite side. Due to scanner boundary effects, typical profiles start 2cm from the edge of the test module.
Page 23: Installation And Removal Of Test Modules
Installation and removal of test modules For most applications there is no need to remove modules from the Catphan®. However, modules can be removed by carefully following these steps. Note the positon of the mounting plate in relationship to the housing before removing it. Remove the four brass nuts that secure the mounting plate to the phantom housing.
Page 24: Optional Phantom Annuli
Optional phantom annuli Warning Before mounting a Catphan® phantom with an annulus onto the Catphan® case, the case must be secured to the table by use of the patient restraint straps or additional weight. If the case is not secured to the table when the phantom is mounted, the case, phantom and annulus could fall off the edge of the table.
Page 25: Dose Phantoms
Dose Phantoms The CTP553 and CTP554 dose phantoms are designed to the Food and Drug Administration’s Center for Devices and Radiological Health specification, listed in 1020.33. The dose phantoms may be mounted on the Catphan® case following the same procedures and precautions used in Initial phantom positioning. The holes will accept a 1/2”...
Page 26: Sample Quality Assurance Program
Sample quality assurance program The following shows a sample QA program. Review the local governing requirements, and the needs of your physicians and physicists when developing a QA program for your institution. This program should only be utilized as a sample. All tests should be conducted at initial acceptance and after major repair such as tube replacement.
Page 27: Automated Computer Analysis Program
Automated computer analysis program To assist our customers The Phantom Laboratory has worked with Image Owl, Inc. to develop a web-based automated service. The Image Owl Catphan® QA service offers detailed CT performance testing and reports with the versatility of Internet access. This service can be used with Catphan®...
Page 28: Bibliography
Bibliography 1. AAPM Report No. 39 Specification and Acceptance Testing of Computed Tomography Scanners Report of Task Group 2 Diagnostic X-Ray Imaging Committee. Published for the American Association of Physicists in Medicine by the American Institute of Physics. May 1993 2.
Page 29 12. Goodenough, Weaver, and Davis Physical Measurement of the EMI Imaging System In: Ter-Pogossian, Phelps, Brownell, Cos Jr., Davis and Evens (eds). Reconstruction tomography in diagnostic radiology and nuclear medicine. Baltimore: University Park Press, 1977: 225-243 13. John M. Boone and J. Anthony Seibert, 1997, An accurate method for computer- generating tungsten anode x-ray spectra from 30 to 140 kV, Medical Physics, v.

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