In this chapter, an example of plan verification is used to demonstrate how to navigate within the myQA Patients applications. The general steps for a typical workflow is:
- Set up the equipment and create detector output calibration,
- Create a patient and a project,
- Import the data to be verified, e.g., DICOM data,
- Perform measurements,
- Verification comparison - data analysis.
- Save the project and print a report
IMPORTANT NOTICE: FREE UP USED SPACE IN MYQA DATABASE
If using SQL Express, deleting patients will not reduce the used space in the database. When the database is full, creating a new database is the only option.
Therefore, we recommend that myQA Patients users deploy a fully unrestricted version of SQL. In this case, deleting patients will free up space in the database accordingly.
The order of sections in this chapter follows the above workflow.
Densities
To perform patient QA plan verification, the plan must be created on the phantom and detector dataset
(such as CT images with RT structures, virtual CT datasets, or extended CT) within the respective treatment
planning system. The user is responsible for controlling and verifying density information entered in the
planning software for the QA plan creation.
Table 2.1. Mass and relative electron density values for detectors that can be used in myQA Patients
| Structure | Material | REDa | Mass density | ||
| Phantoms | miniPhantom, miniPhantom R, and myQA SRS phantom (all variants) | RW3 | 1.012 | 1.045 g/cm3 | |
| myQA SRS phantom^b (with ABS) | ABS | 1.025 | 1.040 g/cm3 | ||
| myQA SRS | Detector area^c | High Z Material | N/A | N/A | |
| Build up and backscatter | ABS | 1.025 | 1.040 g/cm3 | ||
| MatriXX | Detector area^c (Ionization chambers) | Air and High Z Material | N/A | N/A | |
| Build up and backscatter^d | MatriXX Resolution and MatriXX AiR |
ABS | 1.025 | 1.040 g/cm3 | |
| MatriXXEvolution and MatriXXFFF |
TECARAN™ ABS | 1.030 | 1.050 g/cm3 | ||
^a Relative Electron Density is the electron density of the material in e/cm3 divided by the electron density of water (H2 O) at 25°C, i.e., 3.334e1023 e/cm3.
^b Please note, most myQA SRS Phantoms are made with RW3, but a small number of the first phantom
variant were made with ABS.
^c The detector area can be substituted with a homogeneous material such as water / ABS / RW3.
^d The ABS used in MatriXX Resolution and MatriXX AiR are from different manufacturers than the MatriXXEvolution / MatriXXFFF (i.e., TECARAN™ ABS).
Set up Equipment
Note: Please skip this section if the equipment has been set up. Detailed instructions are in Chapter 4, myQA Platform Instructions for Use.
Create a Patient and a Project
Create a Patient and Project Manually
- In the Workspace Navigation, click Workspace Selection button and select myQA Patients (1).
- Click the Patient/Project (2) button and then the Patient browser (3).
- Click Clinics (4) in the ribbon and select the desired machine.
- Click New (5) in the ribbon and then enter the patient properties (name, ID, date of birth, and sex) in the New Patient dialog.
- Click the Create project from select patient icon in the ribbon (6)
Alternatively, a patient and project can be created during DICOM import (see the next section).
Create a Patient and a Project from DICOM Import
- Click Import DICOM in the ribbon of the Patient browser.
- Select an import method in the Select a study to import window. In this example, Query / Retrieve
mode is selected. (For other import modes, see Section 2.6.) - Setup the connection settings (1) and the search criteria (2) in the Select a study to import window, and then click the Query button (3). The resulting patients are listed in (4).
- Check the box of the desired Study listed in (4) and then click Ok.
- In the Import window, tick the Patient box. A patient will be created with the DICOM patient.
- Tick the RTDOSE and RTPLAN boxes, a project will be created with the imported RTDOSE and the DICOM isocenter position from the RTPLAN (if available) will enable the automatic isocenter plane selection function if the DICOM Isocenter Position option is selected (see Section 2.6.5).
- Click to highlight RTDOSE,
- the data can be aligned to the center of the dose cube with the Center Dose Cube button; or shift to a desired position by entering the offsets into the Correct Position field. Click the Reset button to undo the correction.
- the slice orientation needs to be selected under the Select Slice group.
- Click Ok. The selected datasets are imported into the project.
Click the Edit button if the properties, i.e., project name, should be modified: - To open the project, click the Open Project button, , or in the Project tab, double-click
anywhere in row of the project. The project will be opened in the Verification compare page. - To display the imported image, select the image in the Project Explorer panel, and drag it to the B pane.
Example: a plan is dragged to the B pane and the corresponding measurement with a MatriXX detector will be dragged to the A pane.
Perform a Measurement
The measurement data can be obtained by carrying out a measurement or importing the measured data.
After the SW database contains the measurement data, load it to the A pane if it was measured with
a MatriXX (7.6 mm resolution) , or the B pane if it is measured with a myQA SRS (0.4 mm resolution) by
dragging it from the Project Explorer panel.
Note: In general, the lower resolution data should be loaded into the A pane and higher higher
resolution data into the B pane.
General procedure:
- In the Verification compare workspace, click Measurement above the ribbon.
The general steps to carry out a measurement follow the item order of the Measurement ribbon from left to right: - Connect the detector (e.g., MXX RES in this example), turn on the power so it is online.
In the Equipment group, select the correct machine and detector, and then click Connect.
Note: Please ensure an adequate warm-up period before taking measurements. See the respective
device manuals for more information. - Perform background measurement (see Section 5.2, myQA Platform Reference Guide for detailed
information):- Click the dropdown triangle at the lower part of the Background icon, to open the dropdown list, and then enter the sampling time. Default is 20 sec.
- Click the icon at the upper part of the Background icon, the background measurement starts.
When it finishes, the Background icon changes from red to green color. Section 5.2, myQA Platform
Referece Guide.
- Note: For the MatriXX Resolution, when the device is turned on, it automatically performs
background measurements every 20 seconds. However, unlike the manually measured
background, the automatically measured background is only used for compensation; the
defect pixels will not be checked. Therefore, manually perform a background measurement
at least once before any measurements.
CAUTION: AT LEAST MANUALLY MEASURE A BACKGROUND ONCE BEFORE ANY MEASUREMENTS WHEN USING MATRIXX RESOLUTION
Even if the background icon shows that the background has been measured ( ), at
least manually measure the background once at the beginning of the measurement
session so that the defect pixels are identified and removed in the analysis.
- Click the Angle Sensor icon, and then follow instructions in Section 6.2, myQA Platform Instructions for Use, to set up the gantry angle sensor for calibration.
- Click the Settings icon to open the Measurement configuration dialog, and define the settings in the Machine, Detector, and Calibration tabs. For the configuration instructions, see Section 6.1, myQA Platform Instructions for Use
CAUTION: KEEP THE BEAM DETECTION DEFAULT SETTING
It is strongly recommended to keep the Beam detection default settings (factory
settings) which are initially displayed in the Beam Detection tab, depending on the
selected device.
- Modification of these parameters may lead to erroneous QA results.
Pre-irradiate the detector. See descriptions for the corresponding detector in their respective manuals, for the required field size and number of monitor units. - Click the Measurement Mode icon in the middle of the Measurement group and select and setup a
measurement mode. For more information, see Section 6.3, myQA Platform Instructions for Use
CAUTION: DO NOT USE THE SINGLE SHOT MODE FOR MEASURING A ROTATIONAL PLAN
The Single shot measurement mode is not suitable for the measurement of rotational
plans. Do not use the Single shot measurement mode for measuring a rotational plan.
- Click the Start icon and turn on the beam.
- Depending on the measurement mode, the measurement stops automatically or manually. For Manual stop, click the Stop icon (Once the measurement starts, the Start icon becomes Stop icon.).
Measurements with myQA SRS In-Phantom Rotation
CAUTION: MYQA SRS MEASUREMENTS WITH IN-PHANTOM ROTATION
When measurements are performed with in-phantom rotation of the myQA SRS
Detector, ensure that the patient couch is not rotated (couch rotation angle = 0).
Currently, in-phantom rotation is only supported for couch angle zero.
Non-zero in both phantom rotation and couch rotation angles will lead to wrong
angular correction values being applied, and thus to erroneous measurement results.
However, the couch kick can be used when the in-phantom rotation angle is zero.
Actual incidence angle
When the in phantom rotation angle is not equal to 0° in the In phantom rotation box, the actual incident
angle on the myQA SRS detector plane will be calculated automatically by the SW:
Actual incidence angle = Measured gantry angle – In phantom rotation angle
Automatic adjustment of LUTs
The LUTs in the SW are defined with the myQA SRS at 0° in its phantom (i.e., In phantom rotation = 0°). If the detector is rotated, the LUTs will be rearranged according to the actual incidence angle by the SW.
Verification comparison of a TPS with an in phantom rotation measurement
Two dose distributions are comparable only when they are on the same plane. If the myQA SRS is rotated in the phantom, the TPS dose plane must be extracted from the RTDose grid at the same rotation angle. This can be done during the DICOM import. See Section 2.6.4 for detailed description and procedure.
Cyberknife Measurements with myQA SRS
Prerequisites
- The device assembly including the myQA SRS detector, fiducial plate and myQA SRS phantom is ready (see myQA SRS Instructions for Use for more information). A CT image has been taken for the assembly.
- The Cyberknife and myQA SRS device have been defined in the myQA Platform > Equipment setup
workspace (see Chapter 4, myQA Platform Instructions for Use)
To use the lookup table for the 6 MV FFF energy provided in the SW, define the BQI = 0.68 for the
machine. - A patient and a project have been created for measurements in the myQA Patients > Patients/Projects workspace (see Section 2.3).
- Make sure that x-ray imaging is deactivated during beam delivery.
Procedure
- In the myQA Patients > Patients/Projects workspace, use the Open project button in the Project
information section or the Home ribbon, or double-click the project in the list to open the project (see the sreenshot above). - Open the Measurement ribbon. In the Equipment group, select the myQA SRS and the machine, and then click Connect (1)
- Click Background to perform a background measurement (2)
- Click Settings to open the Measurement Configuration dialog (3).
- In the Machine and Detector tabs, check/select/enter the parameters:
- Click the Calibration tab.
Note: See Section 4.3.2. in myQA Platform Instructions for Use for more information on detector
calibrations
CAUTION: USE INFORMATIVE NAMES WITH ADDITIONAL INFORMATION
When performing output calibrations always use informative names for the
calibrations. For the myQA SRS Detector using the myQA SRS Phantom, the type of the
SRS Phantom should be written in the calibration name to prevent mix-up between
different types.
Example: SRS_PhanV2_calibration_05052024 - Check the Apply output calibration box (i) if desired.
- Check the Apply angular and source position correction box (ii).
- Select the lookup table (iii) and energy / BQI (vi) for angular correction. It is recommend to use BQI = 0.68 for 6 MV (FFF).
- Click the Import button (v), then browse and select the plan path xml file that provides the values of
incident beam angles and SADs for the measurements.
CAUTION: IMPORT CORRECTION FILE FROM CORRECT FOLDER
Ensure you are selecting the path.xml file from the correct folder. The plan ID is visible when opening the file. - If the SAD correction parameters should be replaced, click the Edit detector values button (vi) and then enter the new values in the corresponding boxes (vii). See Section 6.1.5, myQA Platform Instructions for Use, for the instructions on determining these parameters.
- Click OK. The color of the status round buttons will change accordingly.
- In the Beam detection tab, keep the default (factory setting) parameter values:
- Select Movie mode (4), sampling time of 0.25 s, and make sure that the Frames box is not checked.
- Click Start (5) and then start to deliver the beams. After all beams have been delivered, press the Stop button, and the integral will be stored in the Measurement folder (6).
A green tick (7) indicates the angular and source position corrections have been applied.
To view the measurement settings or the incident angles, right-click the image in the list (8), then click Properties (9) in the context menu to open the Field of porperties.
Beam Number Verification
When applying a source position correction to a measurement, the number of beams of the measurement will be compared to the number of beams in the plan path xml file. If there is a mismatch, no correction will be applied. An error message will appear.
The uncorrected measured integral will be provided with a red cross in the upper-left corner in the integral image.
Plan Path File Verification
It is possible that a wrong plan path xml file might be imported in Settings even if the beam number is correct. Since Cyberknife operates at a fixed dose rate, the SW calculates the Pearson Correlation Coefficient between the irradiation times of the beams and the number of MUs. If the correlation coefficient γ > 0.8, the correct plan path file is used. If γ < 0.8, the warning message pops up:
In this case, the uncorrected integral is provided, indicated by a red cross in the upper-left corner in the
integral image.
Automatic Postprocessing
For plans with multiple targets, it may happen that some beams might not cross the sensor plane and
only stray radiation can be detected. The signals of these beams are significantly smaller than others and
cannot be detected with the normal process. In this case the SW automatically starts a post processing where a threshold is searched which covers all beams. During the process, a processing bar appears.
Depending on the measurement time, this step can take several minutes.
After the process completed successfully, the angular and SAD corrected integral will be provided. If no
adequate threshold can be found, the uncorrected integral will be stored.
Import Measurement Data
- Right-click the Measurement folder in the Project Explorer panel, and then select Import new field > Import Generic ASCII (*.opg).
- Browse and select the file to be imported.
- Click Open. The data will be loaded into the Measurement folder.
Import Patient Data in DICOM Format
General Description
There are two options for the DICOM import in myQA Patients:
- In the Patient browser (1) in the Patients/Projects workspace (2)
In the Project browser, by using the Import DICOM icon in the ribbon (3) , a patient with the imported DICOM patient header information from the RTPLAN and a project that is attached to this patient and contains the imported DICOM objects (RTDOSE, RTIMAGE, RTPLAN-Fluence …) can be created.
If only RTPLAN is imported, only a new patient will be created.
If only RTDOSE is imported, the project will have the study description as the name if it is available otherwise the study ID.
If an RTPLAN and the assigned RTDOSE are imported together, the project will have the name of the RTPLAN.
If the RTPLAN name is not available in the DICOM file, the RTPLAN Label will be used as project name.
- In the Project Explorer (4) in the Verification compare workspace (5)
By selecting a folder in the Project Explorer in an opened project, and then clicking the Import DICOM icon in the ribbon (6), or right-clicking a folder and then select Import data > DICOM... (7), a folder containing the RTDOSE data will be created under the selected folder.
The Field by field measurement workflow after import option is available if the imported data fulfills the
requirement (Section 2.6.3).
In both cases, the Select a study to import dialog opens:
Select a Study to import dialog (by default, the File based tab is selected)
1: Four modes for browsing DICOM objects.
2: For defining the search criteria or settings of selected method.
3: Displays the search results.
Note: When importing DICOM data, three tags may be imported that can be used in myQA Patients
for pixel spacing:
- Pixel Spacing: used if it is available
- Image Plane Pixel spacing: used if Pixel Spacing is not available
- Pixel Aspect Ratio: used if the above two tags are not available
1 mm × 1 mm is used if all three tags are not available
Browse and Select DICOM Instances - the Select a Study to Import Dialog
In the Select a study to import dialog, select the tab of the desired browsing mode.
For File based and Listening modes:
- If an RTPLAN and the assigned RTDOSE are imported simultaneously, they will be grouped under the Plan Label of the DICOM file.
- If there are more than one RTPLAN and RTDOSE, they will be in different groups according to their
respective Plan Labels (1). - If Plan Label is not available in the DICOM file, the RTDOSE and RTPLAN will be grouped under the name: “Referenced plan not found” (2).
DICOM Import - File based Mode
With the File based mode, the DICOM data are imported offline, e.g., from a local or network storage.
- Click the File based tab (1).
- Type in the location of the folder in the Folder text box (2a) or click the Folder browser button (2b) and then select the folder containing the DICOM data.
- Select a study (3) and then click Ok. The dialog will change to the Import dialog showing the available DICOM instances of the study
- In the Import dialog, select the Orthogonal tab for importing orthogonal planes (Section 2.6.3) or the myQA SRS Arbitrary Plane tab for importing a non-orthogonal plane (Section 2.6.4) as desired.
- Follow the instruction in the opened tab page to finish the data import .
Notes:- By checking the Look in subdirectories box, the studies in the subdirectories are also searched.
- By clicking Add additional files …, a standard Open file dialog will open. More RTPLAN or RTDOSE can be added into the list (3). However, if Update is now clicked, the list will be reloaded from the folder currently selected in the Folder box. The items added with Add additional files ... are removed.
DICOM Import - Query/Retrieve Mode
With the Query/Retrieve mode, the DICOM data are retrieved from a DICOM Server.
- Click the Query/Retrieve tab.
- Enter the parameters to find the correct patient. You can search for a single attribute or for a
combination of several attributes by:- Patient Name
- Patient ID
- Patient Sex (F: femaile; M: male; O: other; *: all)
- Birth Date start, define the starting date for the birthdate range
- Birth Date end, define the ending date for the birthdate range
All parameters can be entered only in part using any part of the text string.
- Click the Query button.
The studies matching the search criteria are listed.
To view the datasets, click a patient and then check the Show Preview box. - In the Import dialog, select the Orthogonal tab for importing orthogonal planes (Section 2.6.3) or the myQA SRS Arbitrary Plane tab for importing a non-orthogonal plane (Section 2.6.4) as desired.
- Follow the instruction in the opened tab page to finish the data import .
DICOM Import - Listening Mode
In the Listening mode, the DICOM browser listens to the network to receive data. The default setting is for
the local DICOM listener, port: 998 and AET (Application Entity Title): IBA_Listening. This port is always open.
Please note, the Port number and AET cannot be changed in this dialog. See Section 5.1.2 for more
information on Dicom Server Configuration Settings.
CAUTION: VERIFY THE SETTING OF THE DICOM LISTENER PORT
Verify the setting of the DICOM listener port. Ensure that the port is available for the
DICOM import. To improve the network security, it is advisable to close unused ports
when not needed.
Pre-condition: The DICOM listener service is running on the desired local or remote computer (see Section 8.2, myQA Platform Instructions for Use)
- Click the Listening tab.
Select a Study to Import > Listening tab. 1: Name the machine sending the DICOM data, 2: Port number and AET of the DICOM listener. On left side of the bottom bar, the DICOM listener settings are displayed if it is ready to receive data.
- Enter the name of the machine sending the DICOM data in the Machine Name box. If it is a local
machine, the box can be left blank. - Click Set; When data has been received from a DICOM Server, the dialog will change to the Import dialog showing the available DICOM instances of the study.
- In the Import dialog, select the Orthogonal tab for importing orthogonal planes (Section 2.6.3) or the myQA SRS Arbitrary Plane tab for importing a non-orthogonal plane (Section 2.6.4) as desired.
- Follow the instruction in the opened tab page to finish the data import.
DICOM Import - DICOMDIR Mode
With the DICOMDIR mode, the DICOMDIR files can be imported.
- Click the DICOMDIR tab.
- Select the root DICOM directory using the Path button to browse for the directory.
- Click Ok. The available studies are displayed.
- In the Import dialog, select the Orthogonal tab for importing orthogonal planes (Section 2.6.3) or the myQA SRS Arbitrary Plane tab for importing a non-orthogonal plane (Section 2.6.4) as desired.
- Follow the instruction in the opened tab page to finish the data import.
Orthogonal Tab Page
Workflow for Importing Orthogonal Plane
The procedure to import orthogonal planes is shown in the Orthogonal tab of the Import dialog:
Orthogonal tab page. The callout numbers on the right are corresponding to the step numbers on the left
If the RTDose file is imported to an opened project and it fulfills the requirements to start the field by field
workflow, if desired, select the Initiate field by field workflow after import button before clicking OK.
Description of the Orthogonal Tab Page
DICOM Import window - the Orthogonal tab
1: Information and instructions
2: Select DICOM instances for import
3: Information and controls (if applicable) of the instance selected in box (2)
4: Options of calculation of isocenter position (see Section 2.6.5)
5: Requirements for starting a field by field measurement workflow
Import status icon and information (2):
: Can be imported. Check the box of an instance (
) for import.
,
and
: cannot be imported. If an instance with one of these icons is highlighted, the information
is displayed in the lower-left corner, e.g., 2a.
By placing the cursor on a status icon, the information will be displayed, e.g.,
RTPLAN
- Patient: When a new RTPLAN instance is selected in the Select a study to Import dialog, a new patient with the patient information in the Patient file will be created.
If importing to an existing project in the Verification compare workspace, the DICOM patient must be the same as the patient in the project. Otherwise, it cannot be imported and the sign appears and this Patient file cannot be imported. - RTPLAN Machine: Displays the information about the machine. The measurements for plan verification should use the same machine with the same energy. It is also recommended to name the machine the same as the name in DICOM.
- RTPLAN Compensator: If its information is available in DICOM data, it can be imported.
Note that the information of RTPLAN Machine and RTPLAN Compensator are not used in myQA Patients - RTPlan: RTPlan must be imported if the isocenter plane should be identified by the SW and the field by
field measurement workflow should be initiated in the DICOM import dialog.
RTDOSE
Highlight the RTDOSE file (2b) to display the center, minimum, and maximum positions of the dose cube in the gantry coordinate system (3a).
Correct Position group (3b)
To correct the position of the dataset, enter the offsets in the X, Y, or Z boxes.
By clicking the Center Dose Cube, the center of the dataset will be aligned to the center of the dose cube
and the corresponding offsets will be automatically entered. The corrections remain for the next import.
By clicking the Reset button, the dataset is set back to the original position.
Select slice group (3c)
Select the desired slice orientation by selecting the corresponding round button (default: XY plane).
Same as for importing a Patient instance, importing RTDOSE to an existing project, the DICOM patient must be the same as the patient in the project.
Calculation of Isocenter Position (4)
DICOM Isocenter Position: Isocenter coordinates calculated from the RTPLAN file
Image position patient: Isocenter coordinates calculated from the image position in the RTDOSE file. It was used as isocenter in myQA Patients SW version 2019-002 and earlier.
See Section 2.6.5 for more information.
Initiate a Field by Field Measurement Workflow (5)
If the RTDose is imported in an opened project in the Verification compare workspace, it is possible to start a field by field measurement workflow (Section 4.2) if the imported data fulfills the requirements.
If yes, this option box is available for selection:
If not, the requirements are displayed:
myQA SRS Arbitrary Plane Tab Page
Workflow for Importing a myQA SRS Arbitrary Plane
Prerequisite: The RTDOSE and RTPLAN were selected, or in case of Cyberknife, the RTDOSE was selected for import in the Select a study to import dialog
If only the RTDOSE is selected, a caution message will appear:
If it is intentional, click the OK button; if not, click the Back button (1) and then select both files.
If you do not need this reminder, you can tick the Do note show this message again box.
- Enter in the in-phantom rotation angle used for the measurement in the Angle box (2).
- Optional: If desired to shift the detector center away from the isocenter, click the Edit button and
then the Allow Edit button in the popup dialog, finally enter the coordinates of the new position in the appropriate boxes (3). - Click the Preview plane extraction button (4).
- Click the OK button (5).
Import dialog - myQA SRS Arbitrary Plane tab page
Note: The IBA Plane Viewer Tool can be used to view a dose plane of a dose grid at any myQA SRS in
phantom rotation angle. It is available on the myQA SW CD and the IBA Dosimetry Help Center
(see the link in myQA Platform > Start page). The latest version can be downloaded from the
link in the About box of the IBA Plane Viewer Tool.
Description of the myQA SRS Arbitrary Plane Tab Page
As myQA SRS can be rotated around the inline axis (in phantom rotation, see Section 2.4.1), to be able to
compare the extracted dose plane with the measured dose plane, it is necessary to extract a dose plane
that is in the same orientation as the myQA SRS detector. The myQA SRS Arbitrary Plane tab is used for this purpose. The workflow is displayed in the tab and also described in the previous section.
The myQA SRS Arbitrary plane import tab is structured as follows:
Import dialog - myQA SRS Arbitrary Plane tab page
Import Information and instructions (1)
Displays the information and instructions for import, the illustration of dose plane (at any defined angle)
coordinate system (Xd, Yd), and gantry coordinate system (X, Y, Z), and the rotation direction (CW - clockwise).
Select file for import (2)
Select the DICOM instances for import. Extracting an arbitrary plane requires importing both RTPLAN and RTDOSE at the same time. If it is not done so, click the Back button and re-select the DICOM instances. The isocenter position is taken as the detector center by default.
Dose grid in the IEC coordinate system (3)
Displays the center, minimum, and maximum values of the dose grid in the IEC coordinate system.
Dose plane extraction angle (4)
The value in the Angle box corresponds to the in phantom rotation angle of the detector, which
corresponds to the value in the Measurement configuration dialog (see Chapter 6, myQA Platform
Instructions for Use). The in-phantom rotation angle can be assigned between 0° and 359°, both inclusive.
By clicking the Reset button , the extraction angle will be set to the default setting 0°.
Controls to assign a new detector center (5)
To shift the detector center, click the Edit button and then the Allow Edit button in the popup dialog. Enter the new values in the corresponding boxes.
By clicking the Reset button , the detector center will be set to the default setting (isocenter in the
RTPlan).
The detector center should be assigned avoiding that the detector edges exceed the boundaries of the
RTdose grid (indicated in 3). The following conditions apply to the detector center boundaries:
- X boundaries: xmin + 60 mm, xmax – 60 mm
- Y boundaries: ymin + 70 mm, ymax – 70 mm
- Z boundaries: zmin + 60 mm, zmax – 60 mm
Due to the precision in the algorithm, there is a tolerance of ±0.1 mm within these boundaries.
Preview of the extracted dose plane (6)
The Preview plane extraction button must be clicked to display the extracted dose plane with the given
settings [angle (4) and detector center (5)].
The mapping from the dose value to color is shown in the color bar. The minimum and maximum values of the dose indicated in the color bar are taken from the imported RTDose file and refer to the global dose values in the dose grid.
The unit is displayed according to the unit given in the RTDose file "cGy" or "Gy". A different coordinate
system (Xd, Yd) is used (see the illustration in 1), corresponding to the X and Y coordinates in the system of reference of the extracted plane. In Xd-Yd system of reference, the detector has fixed dimensions of 120 mm × 140 mm.
OK button (7)
Once the preview is displayed, the import can be finalized by clicking the OK button. Three planes will
be extracted into myQA Patients at the (selected angle), (selected angle - 1°), and (selected angle + 1°),
respectively. Once the extracted dose plane is imported into myQA Patients, the plane is displayed with the Xd and Yd coordinates.
Automatic Isocenter Plane Definition
Isocenter plane is defined as the dose plane at the position of the treatment beam isocenter or closest
to the isocenter and is used for Verification Compare. It can be identified by the SW if RTPLAN is also
imported.
Importing RTPLAN and RTDOSE files from a study
- Tick the RTDOSE and RTPLAN boxes of the selected study and then click OK. The Import dialog opens:
- In the Calculation of isocenter position group, choose the desired position for identifying the isoplane:
- DICOM Isocenter Position
- Image position patientBy default, Image position Patient will be used unless RTPLAN is available and the DICOM Isocenter Position round button is selected.
Isocenter plane is determined based on the selected beam isocenter coordinates as specified in the DICOM RT Plan tags (by selecting the corresponding round button).
- After clicking OK, double-click the project to open it in the Verification Compare workspace.
- In the Project explorer panel, every plane contains information of the plane position [the absolute
position of the plane (1) and distance from the plane to the isocenter (2)]. If this distance is less than or equal to 0.1 mm, it will be set to 0.0 mm by default.An example of imported planes. The Isocenter plane is the one with 0.0 mm distance from the isocenter.
Function to identify the Isocenter plane
Right-click the folder to open the context menu and select the Select Isocenter Plane command. The dose at the isocenter plane will be automatically displayed in the B pane and isocenter plane will be highlighted in the data view of the selected folder. It may be needed to scroll up and down to see it.
Verification Compare – Data Analysis
The Home ribbon in the Verification compare workspace contains the functionalities for comparison data
analysis.
IMPORTANT NOTICE: COMPARABLE IMAGES
Make sure that the data acquired from measurement and imported from the RTPLAN are for the same location (orientation and depth) to be comparable.
IMPORTANT NOTICE: LOCATIONS OF THE TWO DATASETS USED FOR COMPARISON
It is recommended that the higher resolution dataset is selected in the B pane where as the lower resolution dataset is selected in the A pane.
The SW allows two datasets to be compared in both directions. However, the gamma result may be different. In general, if a lower resolution dataset is set as the A data set, a higher pass rate will be calculated. This is because the algorithm searches for the minimum gamma for each point in the A dataset. Therefore, if the B dataset has a higher resolution, it is statistically more likely finding a minimum gamma that passes the criteria. If a detector has a higher resolution than the resolution of the TPS dose grid, the TPS data can be set as the A dataset and vise versa.
The resolution of the TPS data is typically 1 mm to 3 mm, the wired MatriXX is 7.6 mm, MatriXX Resolution is 6.5 mm, and myQA SRS is 0.4 mm. Therefore, it is recommended to place the TPS dataset in the B pane if it is verified with a MatriXX device, whereas, in the A pane if it is verified the myQA SRS device.
IMPORTANT NOTICE: REFERENCE DATA VS EVALUATION DATA
For a correct Gamma analysis, ensure that the measurement is used as the evaluation data, and the imported DICOM data is used as the reference data.
CAUTION: COMPARE GANTRY ANGLE VALUES FOR GAMMA ANALYSIS
When performing gamma analysis, always compare the delivered gantry angle value (displayed prominently when selecting the measured frames) with the value expected from the treatment plan. In case of a deviation, the gantry angle sensor may be defective, and the gamma analysis may lead to erroneous QA results.
- In Project Explorer, click the Measurement folder and then press and drag the measurement data, e.g., to the A pane (for the measurement with a MatriXX detector). In the Import folder, press and drag, e.g., the dose plan to the B pane.
- Alignment of the images in the A and B panes: Option 1 - use the automatic alignment function by
clicking the Align data icon on the right side of the B pane. The Align data… dialog will open showing the alignment information. If the alignment is satisfied, click OK. (see Section 3.4.6, myQA Patients Reference Guide) - Alignment Option 2 - If the automatic alignment is not satisfied, manual alignment can be performed. In the Align data… dialog, adjust the moving rings or/and rotation ring until the profiles on the right are best-overlapped.
Align data tool. 1: Move rings, 2: Rotation ring
- In the Results pane, perform, e.g., gamma Index calculation:
- For the first time an analysis calculation is performed: click the Gamma Index icon.
- After any analysis calculation: click Tools and then select Analysis. Click the gamma dropdown list
and select Calculate Gamma Index. The calculation starts. Wait until the graph display updates.
Please note, the Search distance of the Gamma algorithm shall be always equal or larger than the delta distance.
The maximum output value of the Gamma index algorithm is set to 2.0.
About resampling
During resampling, no explicit center adaption is performed. The resampling is not done with respect to
the position of the pixels at the image center. For the pixel position coordinates, the center of the pixel
with smallest coordinates of the source image is the origin, and the rest of the pixels is 'built' starting from there. The signal of a resampled pixel is the bilinear extrapolation of original neighbor 4 pixels.
Resampling may cause artifacts on Gamma calculation (see details in Section 8.3.2, myQA Platform
Reference Guide). It is recommended to avoid resampling the dose distributions in comparisons using
gamma analysis.
If resampling must be applied, choose the new spacing such that the Resample Factor is (Resample Factor
= Old Spacing / New Spacing) is an integer that is greater/equal to one.
Treatment Plan Verification Approval
To enter the plan verification conclusion, click the Approval icon in the Home ribbon of the Verification
compare workspace. The Approval dialog opens. Select one of the statuses and enter comments if
desired.
The Approval icon is enabled only if the user has the myQA Patients approval permissions. By default, user
rights of physicists has the permission.
Save a Project and Print a Report
Save the project
- Click Save in the Home ribbon of the Verification compare workspace.
Print a report
- Click the upper-half icon (1), the default template of the Plan Verification Report dialog or the last used report template will open, or,
- Click the lower-half icon (2) and select the preferred template in the report template dropdown list (3) to open the corresponding template of the Plan Verification Report dialog:
- In the opened Plan Verification Report dialog, select a template from the Templates combo box if the Default template is selected in the previous step.
- Click one of the buttons on the top right area to export (as Html, Rtf, or PDF format) or print the report.
Note: Only the Plan Verification Report - Default template contains the complete information.
Please use this template for the purpose of verification documentation.
A Report Example