CDRPan®

FOR PANORAMIC SYSTEMS

Calibration

Creating Calibration Filesfor CDRPan Systems

Schick Technologies, Inc.30-00 47th AvenueLong Island City, New York11101

(718) 937-5765(718) 937-5962 (FAX)

Part Number B1051029 Rev. B

Copyright 2001 by Schick Technologies, Inc.All Rights Reserved

Part NumberB1051029 Rev. B

January 10, 2002

&

Printed in the United States of America

This document was originally prepared in English

Many of the designations used by manufacturers and sellers todistinguish their products are claimed as trademarks. Where thosedesignations appear in this document, and Schick Technologies,Inc. was aware of a trademark claim, the designations have beenprinted in caps or initial caps.

CDRPan Calibration B1051029 Rev. B i

Contents

1. Calibration Procedure....................................................................11.1. Tools and Materials ..........................................................................................................11.2. Special Note for Bi-Directional Machines..........................................................................11.3. Step-by-Step Instructions ..................................................................................................2

1.3.1. Create a New Exam................................................................................................21.3.2. Turn Calibration Setup On......................................................................................31.3.3. Take a Flat-Field X-ray ..........................................................................................41.3.4. Measure Pixel Values .............................................................................................51.3.5. Take a Dark Image X-ray........................................................................................61.3.6. Crop Excess Rows ..................................................................................................81.3.7. Exclude Dark Area ...............................................................................................101.3.8. Make Calibration File ..........................................................................................111.3.9. Test Calibration File ............................................................................................13

2. X-ray Filter Placement ................................................................ 15

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Safety Issues

Electrical Concerns

CDRPan conforms to national (U.S.) and international standards for electromagneticcompatibility and electrical safety. A complete list of specifications can be found in theCDRPan User’s Guide.

Mechanical Considerations

The sensor package, the remote module, and the cables of the CDRPan system aremounted outside of the patient area to ensure patient safety and reliable equipmentoperation.

Radiation Concerns

No adjustments or alterations are made to the X-ray source of the panoramic equipment.

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1. Calibration Procedure

1.1. Tools and Materials

To perform the calibration procedure you will need to place the provided X-ray filter overthe X-ray source collimator. This will enable you to take a flat-field image, which is anecessary part of this procedure. After performing the calibration procedure, you will testthe calibration file by taking either a flat-field or non-flat-field image. Remember toremove the X-ray filter from the collimator before taking any non-flat-field images.

1.2. Special Note for Bi-Directional Machines

If your panoramic machine scans in both left-to-right and right-to-left directions, you willneed to create two calibration files, one file for each direction. You should create thecalibration files one at a time. Perform the calibration procedure for either direction, andthen repeat the procedure (starting from the first step) for the other direction.

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1.3. Step-by-Step Instructions

1.3.1. Create a New Exam

Create a new CDR exam. Type in “CAL 1” next to the last name and fill in the first namefield. Select the “Pano 2*2” series, and click OK.

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1.3.2. Turn Calibration Setup On

A. Press and hold down the <SHIFT> key.

B. Click on the System menu, Sensor, and then on Turn Calibration Setup ON. CDRdisplays a message box confirming that calibration mode is on.

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1.3.3. Take a Flat-Field X-ray

A. If you haven’t done so already, tape the X-ray filter supplied with your CDRPansystem over the X-ray source collimator (as shown below). (For additional samples offilter mounting, refer to Section 2.) Reset the panoramic machine to its home position.

B. Click on the upper left target frame in the exam, which tells CDR to acquire an imagein that frame. When the amber LED indicator on the remote module turns on, CDR isready to acquire and transmit an image.

C. Operate the panoramic machine to take a flat-field exposure.

NOTE: If your panoramic machine can acquire bidrectionally – left-to-right and right-to-left– you will need to create two calibration files, one for each direction. Since you can onlycreate one calibration file at a time, CDR will ask which direction you wish to calibrate first.You will only receive this message if the Scan Direction= entry in CDR Options is set toBOTH.

FILTER ON X-RAY SOURCE

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1.3.4. Measure Pixel Values

A. After the image is acquired, CDR displays it in a zoom window. You will see a verticaldark band in the center of the image, created by the reduction in the speed of the X-raysource as it travels behind the spine.

B. Click on the Measure menu, and then on Pixel Value . To measure a pixel’s value,click on it and read the percentage value from the status bar at the bottom of the screen.Pixel values should fall between 30% and 60% (with the exception of pixels in thesaturated band at the center of the image, which will be higher). If they are outside ofthis range, adjust the panoramic machine's technique factor (kV and mA) accordinglyand retake the X-ray.

PLEASE NOTE: For darker images (higher pixel values), increase kV and / ormA. For lighter images (lower pixel values), decrease kV and / or mA.

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1.3.5. Take a Dark Image X-ray

A. Turn off the X-ray source for the panoramic machine. (Because there is no X-rayemission, the dark image can be used to subtract any effect not related X-ray exposure.)

B. Click on the upper right target frame in the exam. When the amber LED indicator onthe remote module turns on, take a dark image (no X-ray) exposure.

C. After the exposure, you may receive a message that CDR read fewer lines thanexpected (the default is 3000 lines). Make a note of the number of lines actually readby CDR. If the number of lines is less than 2700, perform Step 1. If the number ishigher than 2700, perform Step 2.

1. A number less than 2700 suggests the following. There may be a problem withthe positioning relationship between the encoder on the CDRPan sensor and thecodestrip on the drum or cassette transport mechanism. A number less than2700 lines may also appear on some panoramic machines with variable travelsettings where the cassette or drum transport mechanism is not set to maximum.Retake the dark image after checking and / or making adjustments in thesepotential problem areas.

2. Start CDR Options. Click on the Panoramic tab and locate the "Image Width(pixels)" entry. Change the number displayed there to 15 less than the numberreported by CDR. Click OK to save your changes and exit CDR Options.

D. A white image is displayed with a black horizontal line at the center. This line is aplaceholder for pixels located between the two subsensors in the sensor assembly.

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TO SEE THIS LINE, CLICK ONTHE ZOOM BUTTON. THEN,PLACE THE ZOOM CURSOROVER THE IMAGE, AND USETHE LEFT MOUSE BUTTON TOMAGNIFY.

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1.3.6. Crop Excess Rows

A. Return to the exam window and select the flat-field image (upper left frame). Double-click on the image to open it in a zoom window. Click on the Measure menu, and thenon Pixel Location.

B. Click on the left side of the image where the image area transitions from white to gray,and record the column number that appears in the status bar. (The right side of theimage should end at the edge of the zoom window.)

C. Click on the top edge of the image and record the row number that appears in the statusbar.

CropLeft=133

CropTop=147

RECORD YOUR NUMBER _____.

RECORD YOUR NUMBER _____.

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D. Click on the bottom edge of the image and record the row number that appears in thestatus bar. Subtract the row number from 1603.

Crop Bottom=112(1603-1491)

RECORD YOUR NUMBER _____.

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1.3.7. Exclude Dark Area

A. At the center of the image is a dark saturated section. Click on the area just to the leftof that section and record the column number that appears in the status bar.

B. Click on the area just to the right of the dark saturated section and record the columnnumber that appears in the status bar. The area set off between the columns is calledthe “exclusion area” and is not included in the calculations for creating a calibrationfile.

ExcludeLeft=1248

ExcludeRight=1828

RECORD YOUR NUMBER _____.

RECORD YOUR NUMBER _____.

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1.3.8. Make Calibration File

A. Switch to the CDR exam window where the flat-field image (in the upper left targetframe) and the dark image (in the upper right target frame) can be selected.

B. Click on the flat-field image first (a red outline appears around the frame to show it hasbeen selected). Then, press and hold down the <SHIFT> key and click on the darkimage. Both selected images should have red outlines around them.

C. Click on the System menu, Sensor, and then on Make Calibration File.

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D. When the Calibration File dialog box opens, verify the scan direction selected for yourpanoramic machine. In the appropriate text boxes, enter the numbers recordedpreviously and the number of flat field and dark frames selected for calibration.

E. Click Create file. Confirm that a short message appears, verifying that a calibrationhas been successfully created. Click OK to close the message.

F. Exit CDR.

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1.3.9. Test Calibration File

A. In CDR, open the exam you have been using in the previous steps of this procedure. Itis not required that you use the same exam, but you may find it easier to compare thecalibrated and non-calibrated images if they are in the same exam.

B. Take either a flat-field or phantom image and check the image for quality. (Examplesof good images are provided below and in Section 2.)

PLEASE NOTE – Remember to remove the X-ray filter from the X-ray sourcecollimator before taking any non-flat-field images. If you are taking a flat-fieldimage, leave the filter in place for this step.

C. After CDR acquires an image, right (R) and left (L) markers are superimposed on theimage as guides for proper image orientation.

PLEASE NOTE – Only images that have been calibrated will have the R and Lmarkers superimposed on them.

(NON-FLAT FIELDIMAGE OFCRANIAL MODEL –X-RAY FILTERREMOVED)

(FLAT FIELDIMAGE –X-RAY FILTER INPLACE)

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D. When comparing the calibrated and non-calibrated images, notice that the calibratedimage fills the frame window completely, without any white areas above, below, or onthe left side of the image. Also, the calibrated image has an even, consistent qualitywhile the non-calibrated image appears “noisier”, with sharper differences between therows. If you open a calibrated image and magnify it in a zoom window, the horizontalline that represented the gap between the sensors in the sensor assembly will also becorrected and is no longer visible.

NON-CALIBRATED

CALIBRATED

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2. X-ray Filter Placement

The figures and table that follow provides samples of flat-field images and examples of thecorrect position and orientation of X-ray filters. When the filter is positioned correctly, itshould line up with the faceplate aperture and then taped in place. Examples of both goodand poor flat-field images are shown below. If necessary, reposition the filter to obtaingood flat-field images.

Figure 1. Examples of Good Flat-Field Images

Figure 2. Examples of Poor Flat-Field Images

(UNDEREXPOSED IMAGE AND / ORMISALIGNED X-RAY FILTER)

(MISALIGNED X-RAY FILTER)

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Panoramic Machine Example

Belmont X-Caliber

Gendex GX-Pan

Instrumentarium OP-100

Panoramic PC-1000

Planmecca PM 2002 CC/EC

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Panoramic Machine Example

Siemens OP-5

Siemens OP-10

Siemens / Sirona Orthophos

Soredex Cranex

Villa Rotograph