Elekta
iViewGT Electronic Portal Imaging Device
Select the iViewGT Image System
Program
ConvertEPIDImages and ConvertIMATImages
Elekta iViewGT Electronic Portal Imaging Device
Version 3.1 of Elekta’s (Elekta,
When the iViewGT system is put into integration mode, one must select the option of having each segment written out as a single file. As of this writing, an available composite mode does not correctly add up the individual segments, although a final image is available. We have also noted that one might have to interrupt the accelerator between segments to give the iViewGT system time to write out the segment files.
We are providing a utility program here: IviewToDicom to be used in the general case. This utility will read the iViewGT data base and assemble all the segment files for each beam.
IMRT
This utility will then write each IMRT beam out in a single Dicom file coded so that program ConvertEPIDImages can read the files. The manual for ConvertEPIDImages is then to be referred to. Each segment is also written out in a subdirectory for reference only.
VMAT
For VMAT each segment is written out as a separate Dicom file. Program ConvertIMATImages is then to be referred to import the images. The composte image is written out for reference only.
Program IviewToDicom
This utility program will read the iViewGT data base and assemble the segment files for each beam, adding up the segments while applying the scaling factors and putting out both the composite image and images for each segment. The Dicom files are then written out in Dicom format to the new EPID images directory, in sub-directories by the patient name then by the plan name, then by the beam name for the individual segments. The files are coded so that utility program ConvertEPIDImages and ConvertIMATImages can read them. IviewToDicom is licensed separately.
IViewGTDirectory.loc
A text file is read in the program resources directory that contains necessary information of where to find the iViewGT data base. A sample file is shown below:
/* file
format version */ 1
/* number
of systems to follow */ 2
/* for each
system: */
// description of system.
<*Elekta IViewGT on 1*>
//
path to the iViewGT directory where
PATIENT.DBF is:
g:\iview\db
//
translation of L, M, H, energy designations:
L
6
M
10
H
15
// description of system.
<*Elekta IViewGT on 2*>
//
path to the iViewGT directory where
PATIENT.DBF is:
v:\iview\db
//
translation of L, M, H, energy designations:
L 6
M
10
H
18
For each iViewGT system there must be an entry consisting of a
description text field, the path to the system from the computer IviewToDicom is running on, and translations for the letter
L, M, and H to energy in mV. /* to */
are comments not read as well as // to the end of a line. Text fields are set off with <* to
*> if there are spaces in the text field.
One would do an NFS mount which need only be for reading, between the
host computer and the iViewGT system computer. Keep the description of the system fairly
short as the description will appear on the below option menu on the main
toolbar of IviewToDicom shown next below.
Select
the iViewGT
Image System
The main
toolbar is shown below:
Use the first
option from the left menu to select the IViewGT system
if you have more than one from the list in the above file.
Select
the Delivery Type
Next there
is also an option menu to select IMRT cases (more than one segment per beam),
Conventional cases (only one segment per beam), VMAT, and CFS mode. The iViewGT system
marks those image files differently (IMRT and CFS is of type ‘T’, conventional and
VMAT is type ‘P’). However, a file for a
beam name with the letters “cal” in the name that is of type P will be read
with the IMRT and VMAT choice so that the conventional calibration file can
also be included in the list of found beams, except for the case of CFS. Do not make a calibration file of type T
(IMRT) and give it the same plan name as the plan delivered if CFS mode is to
be used. Read in the calibration file
separately under conventional.
CFS
Mode
For CFS
mode, you will be prompted to select the patient from the Dosimetry
Check patient list when you select CFS mode.
To pick a different patient, select CFS again.
You must have first read
in the plan with program ReadDicomCheck.
This progam will need the list of beams in the plan, the gantry
angle for each beam, and the number of segments for each beam, in order to sort
out the integrated images as iViewGT stores the
delivery of all beams and segments under the name of the first beam
delivered. If a plan with the same name
from iViewGT cannot be found, you will be prompted to
select the plan from the list of plans under the selected patient’s name. If the first beam treated cannot be
determined, you will be prompted to select the first beam. However, in this last case, there may very
well be an error as the gantry angle of the first beam treated is known and
should be found from the beam list in the downloaded plan.
Select
IViewGT
Patient
After
selecting the type of plan, select the patient from the iViewGT
data base by hitting the button “Select IViewGT
Patient”. The program will list the
patients found on the iViewGT system and prompt you
to select one.
This is not to be
confused with selecting the patient entry in Dosimetry
Check above for CFS mode.
The program
will then find all files that were integrated for the patient. If more than one plan is found, you will be
prompted to select the plan. The program
will then list all the segment files found, sorted by beam. A very simple example appears below:
One can
remove from the list selected items. The
list is constrained to consider only then latest segments measured.
Hitting the
“Write Dicom Files” button will write out a composite
Dicom file for each beam in the new images directory,
and each segment will be written to a sub-directory. Run program ConvertEPIDImges
to read in these files along with a calibration file and proceed, using a deconvolution kernel for the iViewGT
system. Run program ConvertIMATImages
for VMAT.
The “Write
out the input files” button is for testing purposes and will copy the iViewGT data base files read on the iViewGT
system into the new images directory.
For IMRT cases you will select the composite images. For VMAT, you will select all the segment
images.
Calibration
File
To include a
calibration file, include the text “cal” in the port name. Otherwise the file may be excluded as files
of only type 84 (‘T’) are picked up for the IMRT mode. A non-IMRT field is marked type 80 (‘P’). For CFS mode just select Conventional to read
in the calibration file separately.
Create
Image Report
Select this
toggle button before selecting the iViewGT patient to
get a report on every image found on the system when you do select the iViewGT patient.
This function is useful for diagnosing problems in reading iViewGT data base.
Program ConvertEPIDImages and ConvertIMATImages
Run these programs to read in the Dicom images written here to convert them to in air x-ray intensity fluence for import to Dosimetry Check. The programs are described elsewhere.