10 quality control

Chapter 10 – Quality Control (QC)

This chapter provides detailed instructions for performing the Ventri quality control procedures, and specifies their regular performance schedule.

The information in this chapter is given in the following order:

QC Reports and Images on page 10-2

Printing QC Test Results on page 10-2

Reviewing QC & System Setup Reports on page 10-3

Accessing the Quality Control Utilities on page 10-6.

Daily Quality Control on page 10-9

Periodical NM Calibration & QC on page 10-35

C.O.R. Test on page 10-41

Bar Phantom Test on page 10-49

The default parameters that appear for the QC tests are dependent upon the QC default values selected during system configuration (see QC Default Parameters on page 13-46). Parameters can be changed as desired.

Once a QC procedure is opened, a list of test procedures automatically appears on the left side of the screen.

WARNING

Failing to perform the QC procedures as specified in this chapter may cause serious deterioration in image quality, resulting in misinterpretation of the acquired images.

Direction 2414308-100, Rev. 3, Copyright© 2006 by GE Healthcare 10–1Ventri User’s Guide

QC Reports and Images Quality Control (QC)

QC Reports and Images

The QC report is automatically saved on the Ventri and can be accessed via the Technologist and Admin Reports sub-category in the Logs panel. Refer to Reviewing QC & System Setup Reports on page 10-3.

Trends for values tested during QC can be viewed via the History Browser where they are categorized by the Isotope used and the front end mode. Refer to QC Trend Analysis on page 10-26.

QC reports can be printed to a Windows printer attached to the Ventri. Alternately, a JPEG image file can be saved into an Ventri directory which is accessible from Xeleris for printing. See Printing QC Test Results on page 10-2.

QC reports can be archived using the QC Archive utility. See Archiving QC Reports on page 10-30.

QC images are saved to the Ventri database and can be transferred to the Xeleris for further processing, printing and archiving. See Archiving QC Reports on page 10-30.

It is possible to review QC studies from the Data Management screen. To view the study, select QC images as the Current source and press [View Study].

Daily QC reports are automatically saved in the Daily QC study as a secondary screen capture and can be reviewed on Xeleris.

Printing QC Test Results

If the Ventri computer is connected to a network printer, press [Print] located at the bottom of the QC report.

If a printer is not available, pressing [Print] creates a JPEG image that is saved in the directory d:UtilDb\JPGExport\qc. This directory is accessible from the Xeleris workstation. This file can then be printed from the Xeleris workstation. For additional printer setup information see Modifying Report Printer Settings on page 13-47.

10–2 Direction 2414308-100, Rev. 3, Copyright© 2006 by GE HealthcareVentri User’s Guide

Quality Control (QC) Reviewing QC & System Setup Reports

Reviewing QC & System Setup Reports

Usage

The Logs panel allows the user to view, print, and export reports to HTML for diagnostic purposes.

To access the Logs, perform the following:

Global Navigation Screen

System Setup

Opens System Set-up (see Figure A-1)

Logs Tab Opens Logs panel (see Figure 10-1)

Technologist and Admin Reports

Click Technologist and Admin Reports

NM Daily QCList of NM Daily QC reports appears

Double click on the desired QC report to view.


Reviewing QC & System Setup Reports Quality Control (QC)

Figure 10-1 Logs Panel


Quality Control (QC) QC Data Management

QC Data Management

Table 10-1 Accessing QC Procedure Results

QC Procedure Data Management Transfer to Xeleris

Archive on Ventri

NM Daily QCQC Imagespatient name:NM Daily QC

Manual yes

Periodical NM Calibration & QC QC Imagespatient name:NM Periodic QC

Manual yes

C.O.R. TestLocal Databasepatient name:C.O.R. test

Manual no

Bar Phantom TestQC Imagespatient name:Bar Phantom Test

Manual yes


Accessing the Quality Control Utilities Quality Control (QC)Preparing the Radionuclide Source

Accessing the Quality Control Utilities

The following QC options are available at the basic logon level:

NM Daily QC

Periodical NM Calibration & QC

C.O.R. Test

Preparation for QC Procedures

Preparing the Radionuclide Source

Table 10-2 shows the radionuclide sources, source activity, and collimator that should be used, depending on the QC procedure to be performed.

Source activity units are mCi:


System Setup

Opens System Set-up (see Figure A-1 on page A-2)

Procedure Selection Screen

QC Tab Select QC tab if it is not selected

Click the relevant QC procedure

1 mCi=37 MBq

or

27µCi=1 MBq


Quality Control (QC) Preparation for QC Procedures Preparing the Radionuclide Source

Table 10-2 Required Sources, Source Activity, and Collimators

Source

SourceActivity

Rec.Count Rate Req.

Collim.

Usage

mCi MBq cc/sec NM Daily QC

Period. QC

COR Test

Bar Phantom

Tc99m

Point Source~0.5 18.5 <45 Decoy

Co57

Flood Source~ 10 to

20 370-740 <45 LEHR or LEGP

Tc99m

Flood Source(re-fillable)

~ 10 to 20 370-740 <45 LEHR or

LEGP

Tc99m

Point Source~1 mCi 37 <15 LEHR or

LEGP

Table 10-3 Source Positioning Requirements

Source Tc99m or Co57 Point with an activity of 0.5mCi

Collimator Decoy

Start Position

• L QC D1 for Detector 1• L QC D2 for Detector 2

Note: Daily QC is activated separately for each detector, creating a separate study and report for each detector.

Source Placement

At least 2.0 ma from the active detector.

Rotate gantry so that active detector faces the point source.

a. If distance of 2.0 m is not possible, the point source can be placed closer, but not less than 1.5 m away from the active detector. Positioning the source so close to the active detector may affect the QC result.


Preparation for QC Procedures Quality Control (QC)Preparing the Radionuclide Source

When required in the procedure, the point source should be placed at a distance of at least 3.0 m from the detector, such that the radiation uniformly covers the entire field of view.

Note The minimal size of the flood source should be 240 mm x 420mm in order to provide adequate exposure of the entire FOV and to simplify the positioning of the flood source between the detectors.


Quality Control (QC) Daily Quality Control Preparing the Radionuclide Source

Daily Quality Control

The Daily Quality Control procedures relevant to the scheduled clinical scans must be performed before performing the clinical scans.

The time required to perform these procedures is about fifteen minutes.

WARNING

Failing to perform the relevant daily quality control procedure before starting the corresponding scans may cause non-identification of serious deterioration in image quality, resulting in misinterpretation of the acquired images.


NM Daily QC Procedure Quality Control (QC)Overview

NM Daily QC Procedure

Usage:

The NM Daily Quality Control (QC) procedure should be performed on a daily basis, preferably each morning prior to performing patient scans. The NM Daily QC procedure helps check system parameter stability and verifies that the system is calibrated.

Overview

The QC Report is automatically saved in the Ventri Database, categorized by the Isotope used.

The Ventri system is supplied with Default QC parameters, which should not be modified in most cases. In some cases, it may be necessary to modify parameters based on the type of isotope or the source used and therefore, the QC Mode. In this case, the modes can be modified. These modes are referred to as “Home Positions”.

Special Modes have been defined to support performing QC on each detector separately (LQC D1, LQC D2). The user can define new QC modes that fit specific conditions using System Configuration (see Modifying Gantry Modes on page 13-79).


Quality Control (QC) NM Daily QC Procedure Overview

The table below shows details of a few of the user home positions supplied by the factory.

QC reports can be reviewed any time from the Logs. For more information on the Logs, refer to page 10-3.

The NM Daily QC procedure includes three distinct steps:

Selecting the execution parameters

Running the scans

Computing and displaying the measured results

The NM Daily QC procedure includes the following tests:

Table 10-4 Predefined QC User Home Positions/ModesSt

art P

ositi

ons

Gan

try

Mod

eMotion

Usa

ge

LQC D1

Detectors - L mode

Detector 1 at 180°, Detector 2 at 270° - detectors meet at 225°.Table - fully out of gantry

Daily QC for Detector 1, using a point source directly above the camera; if source is located elsewhere, this home position must be updated.

LQC D2

Detectors - L mode

Detector 1 at 90°, Detector 2 at 180° - detectors meet at 135°.Table - fully out of gantry

Daily QC for Detector 2, using a point source directly above the camera; if source is located elsewhere, this home position must be updated.

QC Procedure Description

Background Rate Measurement test

Performed without a radioisotope in the area. Checks whether there is any radiation in the area that could interfere with image acquisition.

Energy Peak Position and Resolution test

Checks whether peaks are in the correct position and that energy resolution is acceptable.

Uniformity Test This test checks Flood Field Uniformity Stability (not NEMA).


NM Daily QC Procedure Quality Control (QC)Self-healing Procedure

Self-healing Procedure

The NM Daily QC procedure includes a self-healing procedure which attempts to automatically resolve image quality problems that are detected when running this procedure. When image quality deterioration is detected, a pop-up appears (see Figure 10-2).

When this pop-up appears, the user has the option of stopping Daily QC and starting NM Periodic QC in order to diagnose (and possibly fix) the problem. The pop-up also shows the estimated time for NM Periodic QC to finish. If ignored, the pop-up remains and NM Daily QC continues in the background. The popup does not close until either [OK] or [Cancel] are pressed. Any time [OK] is pressed, the self-healing action begins (even after NM Daily QC is completed).

To perform NM Periodic QC, press [OK].

NM Periodic QC begins automatically. The Iterative PM Calibration screen appears after a few seconds.

To continue with the NM Daily QC procedure, press [Cancel].

NM Daily QC continues.

Figure 10-2 Self-healing QC Pop-up


Quality Control (QC) NM Daily QC Procedure Self-healing Procedure

NM Periodic QC Performed

If NM Periodic QC is performed, at the end of the procedure there are two possible scenarios:

The procedure does not solve the problem and a pop-up recommends calling a Service Engineer (see Figure 10-3).

The image quality problem is resolved.

The NM Daily QC continues. In the event that problems are detected during the Uniformity Test (part of NM Daily QC), the following pop-up appears.

Figure 10-3 NM Periodic Test Not Acceptable Pop-up

Figure 10-4 NM Daily QC Uniformity Test Failure Pop-up


NM Daily QC Procedure Quality Control (QC)Self-healing Procedure

To rebuild the uniformity map (for Tc99m only), perform the following:

1. Press [OK].

The Key Parameters screen for Uniformity Maps appears. Verify that 120,000 kcts is set for Stop on counts.

2. Press [Apply].

3. Press [Start].

Uniformity map creation begins. Wait until Uniformity Map Creation is completed.

4. Press [Next] and review the report.

5. Press Uniformity Map Creation (left side of screen).

6. Press [Apply]. A new uniformity map is built.

7. To close this screen, press [Close Uniformity Map Creation].

8. Return to NM Daily QC and run the test again.

Note The Self-healing procedure only builds a Uniformity Map for Tc99m.


Quality Control (QC) NM Daily QC Procedure Performing NM Daily QC

Performing NM Daily QC

Usage

Used to verify image uniformity stability.

During execution of the procedure, look for instructions in the prompt area (at the top) of the NM Daily QC screen.

The NM Daily QC Test consists of four tests which are part of the NM Daily QC flow:

*Relevant only when Daily QC is performed with Tc99m

Although it is possible to skip the Background Test, it is not recommended to do so. The Image Quality Test should be performed only after verifying the background level.

Note The Uniformity test done during NM Daily QC uses a ROI of 1.55 x 1.55 cm2

for the uniformity calculation. The uniformity value received after this procedure should be used to monitor the uniformity stability of the system.

To run the Uniformity Test according to the NEMA standard NU-2001, refer to the Acceptance Test Section of the Ventri Service Manual.

QC Procedure Description

Place Decoy* The operator should replace the collimator with the decoy collimator.

Background TestPerformed without a radioisotope in the area. Checks whether there is any radiation in the area that could interfere with image acquisition.

Image Quality TestChecks whether peaks are in the correct position and that energy resolution is acceptable. This test also checks Flood Field Uniformity Stability.

Replace Collimator* The operator should replace the decoy with the standard collimator.


NM Daily QC Procedure Quality Control (QC)Performing NM Daily QC

Setup

For Co57 Flood Source

Go to GantryMount the collimators to be used (either LEHR or LEGP, see Table 10-2).

For Tc99m Source

Go to GantryMount the Decoy collimators on the detectors (see Table 10-2).



Image QCDouble-click

[NM Daily QC]

The system displays the Daily QC Parameters Dialog for the Background Test (see Figure 10-5).

Background Test

Verify that the correct detector(s) is selected (Both Detectors, Detector 1 or Detector 2). Verify that correct Start position is selected.

Note: The duration of the Background Daily QC Test is directly related to the Termination Criteria selected.

[Apply]



Go to Gantry

<SET> on the RCU

The detectors move to the relevant position. Wait for motion to stop.

[Start] or <GO>

The Background Test starts. It is possible to view the X, Y, or Energy Spectrum.

When the test is completed, confirmation appears in the prompt area.

[Next] at bottom of screen

The Background Test Report appears. Review the report (see Reviewing QC Test Results on page 10-23).

Background Test Report

Image Quality Teston left side of screen

The NM Daily QC input dialog opens (see Figure 10-6).

Image Quality Test

Verify that the correct Energy Session is used (either Tc99m or Co57).

Verify that the correct Start Position is selected (see Table 10-5). It is recommended to use the same Start Position that was used for the Background test.

Verify that the correct Detector parameter (Both Detectors, Detector 1 or Detector 2) is selected. The detector that is selected must be the detector that is radiated by the source.

Verify that the Stop Condition is 4000 kc.

To modify the default Stop Condition value (4000 kc), type in the new value and press <Enter>.

[Apply]



Go to Gantry

• Press <SET> on the RCU.

The Detectors move to the relevant position (the position was probably reached when performing the Background Test). Wait for motion to stop.

• Position the radiation source.

[Start] or <GO>

The system starts to acquire data for the QC Test.

A progress indicator is displayed below the images.The test functions are implemented automatically in the following sequence:• PHA and Flood STATIC acquisition

begins.• Peak position, energy resolution and

CFOV integral uniformity calculation for each Detector.

Notes:

The time required for the Daily QC Test is directly related to the parameters selected for Acquisition Total Counts and to the intensity of the radioactive source.

Acquisition manual stop is provided by pressing [Stop] or <PAUSE>. The Daily QC procedure continues to the next step.

QC Report



The QC results appear on the screen. The input parameters and Detector results are displayed.

Review the QC report (see Reviewing QC Test Results on page 10-23).

If NM Daily QC is done for each detector separately, click on Background Test (Detector 2).

[Close NM Daily QC] or [Close Session]

To be pressed when NM Daily QC is completed.



Figure 10-5 Daily QC Background Test Parameters Dialog



Figure 10-6 Daily QC Parameters



Table 10-5 NM QC Start Positions

Usage Start PositionDefault

Detector Configuration

Used for point source for Detector 1 L QC D1

Used for point source for Detector 2 L QC D2

D1

D2


Quality Control (QC) NM Daily QC Procedure Reviewing QC Test Results

Reviewing QC Test Results

The NM Daily QC Report screen displays the following:

Input Parameters: Displays parameters selected by user.

Detector Results: Displays all of the test results for each detector.

Comments: The user can add comments relevant to the test.

Log: Displays system information on start and stop time of tests and system errors.

Figure 10-7 Daily QC Test Results


NM Daily QC Procedure Quality Control (QC)Reviewing QC Test Results

Acceptable Results

1. Review all the test results. Results that appear in black are those that passed the acceptance criteria, i.e. are within the limits indicated in the right column of the results table. Results that appear in red are those that failed. The NM Daily QC procedure is successful only if none of the tests failed.

2. If any of the of the tests failed, refer to NM Daily QC Test Failure on page 10-25.

3. The name that appears in the name field at the top of the screen is the user login name. To change the name (e.g. if a default logon was used), type a new name in this field. Click [Save] when done.

4. To add comments to the Comments area, place the cursor in the comments area and type in comments. Click [Save] when done.

The test results can be accessed at any time from the Logs panel. Refer to Reviewing QC & System Setup Reports on page 10-3.

Table 10-6 Background Test Acceptable Results

L-mode without collimator < 2.5 kc/s

Table 10-7 Image Quality Test Acceptable Results

Isotope Tc99m Co57

Peak Position (keV): 140 ± 3 122 ± 3

Energy resolution (%) < 11.0 < 12.0

CFOV Integral Uniformity (%) < 5 < 5

Note In case of high background level use a source with a rate 10 times higher than the background level but not higher than 45 kc/s.

Note If Daily NM QC was performed for each detector separately, then a separate report is created for each detector.


Quality Control (QC) NM Daily QC Procedure NM Daily QC Test Failure

NM Daily QC Test Failure

If the NM Daily QC test fails, check which test failed and use the recovery suggested below and repeat the QC procedure.

If the procedure still fails, review the Logs (located in bottom right area of QC Report Results). If significant error messages appear, contact qualified GE Service Personnel for assistance.

If the reason for test failure is not found, perform Periodical NM Calibration & QC on page 10-35.

QC Test Recovery

Background

Verify that the Source is not leaking or that there is no other source of radiation in the immediate area (such as an injected patient waiting behind the wall or an open radioactive source).

Peak PositionIf the Peak Position (Energy Peak) test fails, verify that the correct isotope parameter was selected. If the test fails, perform the Periodical QC test.

FWHM If the test fails, perform the Periodical QC test.

Uniformity TestIf the Uniformity Stability Test fails, examine the images for Detector 1 and Detector 2 and verify that the radiation source is positioned properly.


NM Daily QC Procedure Quality Control (QC)QC Trend Analysis

QC Trend Analysis

Usage

The History Browser allows the user to compare system QC reports for diagnostic purposes.

To access the History Browser, perform the following:


System Setup

Opens System Set-up (see Figure A-1)

Logs Tab

Select Logs tab

History Browser

Double-click

Image Quality Test

Opens a list of QC isotopes.

Click on the appropriate isotope. A list of QC reports for this isotope appears in the panel on the right.

Select QC reports to be compared in the panel on the right.

Filter

Select the desired filter (see Figure 10-8)

The Browser dialog includes a filter which allows the user to select reports from different periods of time (All Dates, Last Month, Last 2 Weeks, Last Week, Last Day, Last Hour).


Quality Control (QC) NM Daily QC Procedure QC Trend Analysis

[Compare Reports]

Select parameters to compare (see Figure 10-9)

[Next]

Select the tab for the parameter to view the trend curve and statistics for the related parameter (one curve for each detector).

Whenever a range of acceptable results exists, it is indicated on the graph by two lines, one red and one green. The graph of tracked values is represented by a yellow line and is expected to stay between the two (red and green) acceptance limits. The vertical locator can be dragged on the graph to identify the date of a specific measurement.

Optional:

[Export Raw Data]

Saves the comparison results in an Excel format (.csv) file.

[Close]

Returns to the list of QC reports for the selected isotope.


NM Daily QC Procedure Quality Control (QC)QC Trend Analysis

Figure 10-8 History Browser and Filter


Quality Control (QC) NM Daily QC Procedure QC Trend Analysis

Figure 10-9 History Browser: Select Parameters to Compare


NM Daily QC Procedure Quality Control (QC)Archiving QC Reports

Archiving QC Reports

Usage:

To save QC reports for later reference.

Clear space for QC reports.


System Setup

Opens the System Set-up Non-clinical Utilities (see Figure A-1)

Logs Tab

Opens Logs panel (see Figure 10-1)

Archive QC Data

Double click. Opens Archive QC Data screen.

Archive QC Data Screen

Select type of QC data

Select either data created by technologist or all logins.

Type in archive location

Type in name of Archive Location or select using [Browse]. It is recommended to archive to a CD.

Clean QC data created prior to:

Options are three months, two months, or one month, or now (clean all data).


Quality Control (QC) NM Daily QC Procedure Archiving QC Reports

Keep reference report every:

Leave reference reports for each utility (don’t clean) on the computer.

Options are every one week, two weeks, one month, or not leave any report.

[Start]

Starts QC Archive. When completed, the Reports Archive appears, showing a list of the QC data that has been archived.

By default, data is saved in D:\Backup. The archive name contains the string Backup, the name of the computer and the date of the backup.



Figure 10-10 Archive QC Data


Quality Control (QC) NM Daily QC Procedure Archiving QC Reports

Restoring QC Data

Usage:

Review QC data no longer saved on the disk.

Analyze trends including QC data no longer saved on disk.


Insert the backup CD-ROM into the drive.

System Setup

Opens the System Set-up Non-clinical Utilities (see Figure A-1)

Logs Tab Select Logs tab (see Figure 10-1)

Double click. Opens Restore QC Data screen.

Restore QC Data Screen

Type in archive name to be restored or select using [Browse]

Select data to be restored.

[Start]

Starts QC Restore. When completed, a list of the QC data that has been restored appears.



Figure 10-11 Restore QC Data Screen With Browse Selected


Quality Control (QC) Periodical NM Calibration & QC Description


Usage:

Periodically used to re-calibrate the photomultiplier gain and to verify the image uniformity.

Should be performed only if NM Daily QC is close to the failure limit.

Description

Periodical NM Calibration & QC is a crucial procedure which permits the user to obtain full performance from the Ventri system. This procedure should be performed periodically with an adequate source.

The Periodical NM Calibration & QC performs all of the tests in the NM Daily QC procedure plus Iterative Gain Calibration. During Iterative Gain Calibration (Iter) the photo-multipliers gain is re-calibrated. This calibration is automatically performed when Calibration and Image Quality test is started. The test time is approximately ten minutes.

The Periodical NM Calibration and QC utility includes five distinct stages:

Place Decoy–Relevant only when Daily QC is performed with Tc99m. The operator should replace the collimator with the decoy collimator.

Background Test

Source Positioning Acquisition

Calibration and Image Quality Test

Replace collimator– Relevant only when Daily QC is performed with Tc99m. The operator should replace the decoy with the standard collimator.

The Calibration and Image Quality Test runs automatic functions in the following sequence:

Iterative Radioactive Calibration.

PHA and Flood STATIC acquisition

Peak position, energy resolution and CFOV integral uniformity calculation


Periodical NM Calibration & QC Quality Control (QC)Periodical NM Calibration & QC Execution

This procedure is performed for each detector independently or for both detectors simultaneously.

Periodical NM Calibration & QC Execution

To access the Periodical NM Calibration and QC procedure, click on System Setup. Select the QC tab and then double-click Periodical NM Calibration & QC. For additional information refer to Accessing the Quality Control Utilities on page 10-6.

Important The isotope selected during system installation will be selected by default.

Changing this selection can cause calibration problems.

Do not change this selection without consulting your service representative.

Important This procedure can be run with a Tc99m source or with a Co57 source. However, it is strongly recommended to always use the same isotopes (Tc99m or Co57) and not to switch between the isotopes.

Tc99m is the only isotope to use with the Decoy Collimators.

The recommended count rate should be less then 45 kc/s

Note The Source Positioning Acquisition stage can be skipped if the operator is experienced with the appropriate positioning of the source for achieving a favorable calibration.


Quality Control (QC) Periodical NM Calibration & QC Periodical NM Calibration & QC Execution

Setup

For Co57 Source

Go to GantryMount the collimators to be used (either LEHR or LEGP, see Table 10-2).

For Tc99m Source

Go to GantryMount the Decoy collimators on the detectors (see Table 10-2).





The system displays the Periodical NM Calibration & QC Parameters Dialog for the Background Test

Background Test

Verify that the correct detector(s) is selected. (Both Detectors, Detector 1 or Detector 2).

Note: The duration of the Background Daily QC Test is directly related to the Termination Criteria selected.

[Apply]

Go to Gantry


Periodical NM Calibration & QC Quality Control (QC)Periodical NM Calibration & QC Execution

<SET> on the RCU

The detectors move to the relevant position (in H or L mode). Wait for motion to stop.

[Start] or <GO>

The Background Test starts. It is possible to view the X, Y, or Energy Spectrum.

When the test is completed, confirmation appears in the prompt area.


The Background Test Report appears. Review the report (see Reviewing QC Test Results on page 10-23).

Source Positioning Acq. on left side of screen

The system displays the Source position Acq. Parameters Dialog.

Verify that the correct Start Position is selected (see Table 10-5).


[Apply]

Go to Gantry

• Press <SET> on the RCU.

The Detectors move to the relevant position. Wait for motion to stop.

• Position the radiation source.

[Start] or <GO>

The system starts to acquire data for PHA and Flood STATIC acquisition.

The purpose of this image is to ensure adequate exposure of the entire FOV. If necessary, modify the position of the source and press [Clear].

When FOV exposure is considered satisfactory, press [Stop].

The procedure continues to the next step.


Quality Control (QC) Periodical NM Calibration & QC Periodical NM Calibration & QC Execution


Ignore the results of this report.

Calibration & Image Quality Teston left side of screen

The system displays the Calibration & Image Quality Test Parameters Dialog

Verify that the correct Start Position is selected (see Table 10-5).



The [Start] button is enabled.

[Start] or <GO>

The utility performs an automatic sequence:• Iterative Radioactive Calibration.• PHA and Flood STATIC acquisition• Peak position, energy resolution and

CFOV integral uniformity calculation

If the calibration is done for each detector separately, repeat the procedure for Detector 2.

When completed, the Calibration and Image Quality Test Results appear. Review test results.

[Close NM Daily QC] or [Close Session]

To be pressed when Periodical NM Calibration is completed.


Periodical NM Calibration & QC Quality Control (QC)Periodical NM Calibration Test Results

Periodical NM Calibration Test Results

Review the QC report that appears at the end of the test. The test report that appears has the same format as the NM Daily QC Test.

For additional information refer to Reviewing QC Test Results on page 10-23 and QC Reports and Images on page 10-2

Table 10-8 Periodical NM Calibration Acceptable Results

Isotope Tc99m Co57

Peak Position [keV] 140 ± 2 keV 122 ± 2 keV

Energy Resolution [%] < 11.0 < 12.0

CFOV Integral Uniformity [%] < 5 < 5

Note The tolerance for the Peak Position is different from NM Daily QC tolerance.


Quality Control (QC) C.O.R. Test

C.O.R. Test

Usage:

In order to reconstruct tomographic images, it is essential that the multiple views be accurately back projected to the location of origin. Rather than require perfection of mechanical motion, a method is provided to calibrate the projection location based on observed image location. This calibration is referred to as COR correction calibration.

This test is used to check the Center of Rotation correction of the Gantry and the detectors.

The following source and collimator should be used:

The test should be performed once a week or according to local regulations.

Radioactive Source Activity Collimator

Tc99m or Co57 Point Source 0.8 – ~1 mCi LEHR or LEGP


C.O.R. Test Quality Control (QC)Source Positioning for C.O.R. Test

Source Positioning for C.O.R. Test


QC TabSelect QC tab if it is not selected

C.O.R. QCOpens the folder.

C.O.R. TestThe Source Positioning Key Parameters screen appears. The Start position should be L QC D1.

Source Positioning Acq. under COR Test L-mode (left side of screen)

Verify that the correct parameters are selected.

Source Positioning Key Parameters Screen

Corrections Tab

Verify that the correct parameters (energy session & collimators) are selected.

[Apply]The C.O.R. Calibration Source Position screen appears.

<SET>on RCU

Wait until automatic motion is completed.


Quality Control (QC) C.O.R. Test Source Positioning for C.O.R. Test

Adjust the source position so that its image is inside the red circle (ROI) on both detectors.

Use the following tips in order to position the source within the circles:• Verify that <SET> was pressed on the

RCU.• Verify that detector radius was not

changed.• In order to shift the y axis position, use

the table IN/OUT motion.• In order to shift the x axis position, use

the table UP/DOWN motion.• If only one detector is corrected, verify

that the source is positioned in the center of the table.

[Start]

Source Position Acquisition begins.

The purpose of this acquisition is to confirm adequate source position. In addition you may need to determine the time per projection in the following Tomo Acquisition.If the source is very strong, you can use a lower time per projection value.

[Cancel]When done, press [Cancel] to stop and discard the acquisition.


C.O.R. Test Quality Control (QC)C.O.R. Test Procedure

C.O.R. Test Procedure

Source Positioning Key Parameters Screen

COR Test Acquisition under COR Test L-mode (left side of screen)

The Acquisition Key Parameters screen appears (see Figure 10-12).

Verify that the correct parameters are selected. Modify parameters, if necessary (e.g. set Stop on Time per projection according to: for about 5 kc/s rate per detector set 5 sec per projection)Select the correct energy session (Co57 or Tc99m)Note: The radius will be automatically set later.

[Apply]

<GO> on the RCU

Acquisition begins. Wait until acquisition ends (Progress Bar shows 100%).

COR Test Processing (left side of screen)

The C.O.R. Test Processing screen appears. Select the appropriate image. The default is the latest acquired image.

[Next]

The C.O.R. Test Results are displayed (see Figure 10-13 and Figure 10-14). See Reviewing C.O.R. Test Results on page 10-47

[Next]The next C.O.R. Test Results Report appears. Results that are outside the allowed values are marked in red.


Quality Control (QC) C.O.R. Test C.O.R. Test Procedure

Note The Source Positioning Acquisition stage can be skipped if the operator is experienced with the appropriate positioning of the source for achieving a favorable calibration.

Figure 10-12 C.O.R. Test Acquisition Key Parameters


C.O.R. Test Quality Control (QC)C.O.R. Test Procedure

Figure 10-13 C.O.R. Test Processing—Graphs


Quality Control (QC) C.O.R. Test Reviewing C.O.R. Test Results

Reviewing C.O.R. Test Results

The graphs of x and y deviations are displayed on the first page. The yellow lines represent a visual reference range. The graphs of detector 1 appear in blue while detector 2 is red.

The second page contains the table with measured COR Residual values, derived by computation from the above graphs.

Check in the test report whether X and Y residuals for both detectors are acceptable as shown below.

Figure 10-14 C.O.R. Test Processing—Tables


Quality Control (QC) Bar Phantom Test Reviewing C.O.R. Test Results

Bar Phantom Test

Usage:

Periodically used to test the system resolution and to verify the image quality.




[Bar Phantom Test]

Bar Phantom Test

User is instructed to replace the Imaging Collimator with the Bar Phantom.

Bar Phantom Acq (Det 1)(left side of screen)

Verify that the correct detector(s) is selected (Detector 1 or Detector 2). Verify that correct Start position is selected.

[Apply]

Go to Gantry

<SET> on the RCU

The detectors move to the relevant position. Wait for motion to stop.


Bar Phantom Test Quality Control (QC)Reviewing C.O.R. Test Results

[Start] or <GO>

The Bar Phantom Acquisition starts.

When the acquisition is completed, confirmation appears in the prompt area.


The Bar Phantom Test Report appears. Review the Bar Phantom acquired image. Verify that the lines appear clearly in all four quarters of the image (see Figure 10-14).

Replace Collimator (left side of screen)

Replace the Bar Phantom with the Imaging Collimator

Perform test for second detector

Figure 10-15 Bar Phantom Test Report


10 quality control

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