THANK YOU
… for looking at this web
site for the VALIDictorianÒ system for IMRT
validation.
___________________________
Contents of this site:
Introductory
Comments
(and contact information)
VALIDictorianÒ Screen samples
(35 pages, but we want to
"show-off" our superiority)
Advantages
of Film over Diode Array
(Look for it - You may find it very
interesting
especially if you are considering a
diode array)
Comments on the Validation Procedure
(A
useful general discussion)
IMRT
planning checklist
(Our gift to you
Feel free to use this for your own IMRT
program)
___________________________
Introductory
Comments
If you are contemplating starting an IMRT program or
would like a more simple method of validating your existing IMRT program, you
have found VALIDictorianÒ, the right product to do
the job most efficiently and accurately.
Are you aware of the complexities of other film
scanner systems?
The VALIDictorianÒ programs are easy to use
and intuitive, unlike some other notoriously difficult to use TLA film scanner
systems. Some of the various screens
that are used by VALIDictorianÒ to accomplish the
validation procedure are presented here.
Those images should demonstrate the more easy to use procedures and the
simple, intuitive side-by-side presentation of the data input and
comparison. There is also some sample
output included in the following presentation.
Are you considering a diode array?
Following the presentation of the VALIDictorianÒ screen images, there is a brief discussion
of the superiority of this system over the limitations of a typical diode array
system. You may already be aware of the
deficiencies of other major providers of validation systems and should
therefore be able to understand the superiority of the VALIDictorianÒ system for accuracy, ease of use,
versatility and readily available, reliable functionality.
Are you ready for an IMRT validation system to get
you going quickly and easily?
We can help you set up an IMRT validation procedure
to give you the confidence to initiate a new IMRT treatment delivery
program. The VALIDictorianÒ can also replace your current cumbersome,
imprecise validation system to provide a greater confidence in delivering very
complex IMRT treatment plans.
For more information about the VALIDictorianÒ system, its various configurations and their
costs and to determine when you might be able to be placed on the delivery
schedule, you may contact us at:
Medicalibration
(209) 524-6789
or at
CNMC: (800) 635-2662
or Sales@VALIDictorian.com
Now--- See the following
information:
MAIN
MENU
This
is the main menu that appears when you start the programs. It checks validity of the users license and
presents across the top of the screen the various options that are available
for the validation procedure.
This
starting "Main Menu" is available from any of the other screens and
this is the screen where you can access all of the VALIDictorianÒ capabilities. This is also the screen where you can exit all of the programs
when you are done.
If
you have installed the FREE demonstration version, that status will be
indicated when you start the programs. When
you have purchased a full license that will be indicated on this screen.
For a FREE demonstration version of theses programs,
contact us at either: Medicalibration (800) 782-7360
or at CNMC
(800) 635-2662
Enter/Edit
Patient Information
When
you start a new patient or edit the information on the current patient, the
following screen is presented where it is easy to enter all the necessary
patient data. If you are entering
patient data from a DICOM file, much of this information will able to be
imported from those files. This
capability to enter the patient information is intended to make the
VALIDictorianÒ as versatile as possible.
Phone if you would like further information (209) 524-6789
CHECK
STATUS
As
the validation procedure progresses, this 'Check Status' screen is available to
show you what data has already been entered for the validation procedure, its
status and what additional information may yet be needed This screen is intended to make the
VALIDictorianÒ process of validating the
IMRT treatment as easy as possible. It
provides assistance in accumulating and preparing the information for a proper
validation. A More complete explanation
of this process is included in this site at the end under the HELP section and
the section that describes the entire validation procedure. This is just another example of how the
VALIDictorianÒ makes IMRT validation a
reasonable and accurate procedure.
Phone for information on how you can order your own VALIDictorianÒ system (209) 524-6789
Get
Film
The
film needs to be entered into the computer system. This is very easily accomplished using the provided film scanner
and the VALIDictorianÒ software. This module has many preparation capabilities
available to make it easy to prepare the input scan for the validation
procedure. Not only does VALIDictorianÒ make this procedure quite easy, the
VALIDictorianÒ system also utilizes a more
reasonably priced Microtec flat bed scanner.
(See the section where we describe the virtues of this scanner). As always, VALIDictorianÒ is designed to make the validation system
economically reasonable as well as completely accurate and capable. If you want more information on the film
scanner we use, you can contact us by eMail or at (209) 524-6789
ALIGN
After the film scan and the dose map are entered,
the VALIDictorianÒ provides some simple
alignment tools to make it very easy to align the dosemap with the film
scan. The configuration of these
VALIDictorianÒ screens is particularly
designed to overcome the limitation of many other film scanner based
systems. Where other systems may go
awkwardly from operating to operation, the VALIDictorianÒ keeps everything clearly side-by-side for a
clear understanding of the status of the comparison at all times. This is a major advantage of other TLA
systems that have been proven to so difficult to comprehend and use. If you want to upgrade an existing TLA
system, contact us and you may find that most of your existing hardware is
still applicable and that we will be happy to be able to replace that
cumbersome system with the VALIDictorianÒ Phone for details from us
at (209) 524-6789 or from CNMC at (800) 635-2662
CHECK PRESCRIPTION
In order to do a proper validation, the
VALIDictorianÒ allows the user to enter
the exact prescription as it is intended to be delivered to the patient. Options for normalization method and
normalization point are provided as well as the ability to specify the cGy dose
and Dose delivery point. Again the
VALIDictorianÒ excels in its versatility
and in its ability to provide for the requirement of radiation therapy. The developers of the VALIDictorianÒ are based in the radiation therapy community
and not just in imaging and consequently the VALIDictorianÒ has been designed to the special needs of
the radiation therapy community. You
may get purchase information from us at (209) 524-6789 or from CNMC at (800) 635-2662
CALIBRATE THE FILM AND DOSE MAP
The
same align screen includes the ability to define the dose vs. Gray-scale
correlation of the two images. This use
of the same side-by-side presentation makes it easy to see exactly what is
being accomplished. The VALIDictorianÒ uses our own proprietary algorithms and
method for correlating the dosemap to the film scan and those methods and
algorithms have been designed with the need for accuracy at it applies to
patient applications in the radiation therapy community. For information on the details of this
methodology you may contact us at (209) 524-6789
HISTOGRAM
PRESENTATION
Histograms
of the density frequency are available for both the film and the dosemap. This is an easy way to see if the two images
are going to be compatible for the validation procedures. Again, you can see the logical side-by-side
VALIDictorianÒ comparison of the procedure
in terms of alignment and in terms of the histograms of the dose frequencies.
CORROLATE
There
is a very easy (patent pending) method provided to enable the correlation of
the gray-scale presentation to the true dose cGy values. This makes it very easy to enable the exact
correlation of the doses to the film and dosemap images. This allows you to enter exact ion chamber
measurement for the ultimate in accuracy and valid comparison of the film scan
with the dosemap. So easy, drag the
indicator to the chosen position and enter the measured dose at that
point. This is done for a zero value
and a calibration or prescription dose on each image. The appropriate calibration curves are then adjusted through
these known points to enable accurate values to be obtained from the
images. You can phone us at (209)
524-6789 for additional details or to order your own VALIDictorianÒ system so you can have the confidence that
this accuracy can supply.
COMPARE
This is the major VALIDictorianÒ verification module and it is where the two
images are actually compared. Each image may be displayed independently. There are several comparison methods able to
be used. They will be demonstrated on
the following pages. To fully
appreciate the versatility of the VALIDictorianÒ you can purchase your own
system and have it fully operational within hours of its deliver on your
site. To initiate the order for your
own VALIDictorianÒ IMRT validation system,
phone (209) 524-6789 or CNMC at (800) 635-2662
COLOR
TINTS
Just
one way to display the image densities is as a color tint
OVERLAY
ISODOSE LINES
The
isodose lines may be overlaid on either the dosemap or the film scan.
DIFFERENCE
MAPS
The VALIDictorianÒ verification module
presents an enhanced difference of the two images for careful visualization of
those differences more clearly. This
enhanced difference is enabled by a special procedure where the differences are
presented as percentage of the prescription.
The extra fine resolution of the differences is accomplished by a
proprietary algorithm that expands the resolution by limiting the full-scale
gray-scale display to represent only +/- 25 percent of the prescription
level. This is to accentuate very small
differences between the two images. To
take advantage of this very special and very accurate ability of the
VALIDictorianÒ to discriminate very small
differences, call (209) 524-6789 or
CNMC at (800) 635-2662
to purchase your own system.
DIFFERENCE
AS COLOR TINT OF LIMITS
The difference in the gray scale image can be visualized
more clearly in terms of areas that are above or below some user definable
difference limits. These user specified
and adjustable limits are used to convert the gray-scale image to a color tint
where red is in regions where the film show the delivered dose is greater than
expected and yellow shows regions where the film shows the delivered dose to be
less than expected. Green is within the
user specified limits. This makes it
very easy to check the acceptability of the correlation. If you want a very easy way to check the
acceptability of the correlation for your own IMRT treatment delivery program,
you may order your own VALIDictorianÒ IMRT validation system by
calling (209) 524-6789 or CNMC at (800) 635-2662
DIFFERENCE
ARE ADJUSTABLE
Single key-presses are able to adjust the allowable
difference limits in 1% steps from +/- 1 percent to +/- 20%. It is assumed that you shouldn't ever have
to accept more than 20% differences and less than 1% differences are also not
allowed. If you have n IMRT program and
are interested in confidence and accuracy in the validation procedure, you know
how to order your own VALIDictorianÒ by calling (209) 524-6789
or CNMC at (800) 635-2662
HISTOGRAMS
The
compare screen also has the ability to present a comparison of the two, in
terms of histograms of the frequency of pixels within the dose ranges presented
in the two images.
Just
more of the special capabilities of the VALIDictorianÒ (209) 524-6789
PROFILES
Any
line may be drawn through either of the images and the profile along that line
in both images can be presented. A
difference profile is also presented to evaluate the /actual difference as
expressed in terms of a percent of the prescription dose.
OVERLAY
DOSE ON FILM or (FILM ON DOSE)
The isodose lines from either image can be overlaid
on the other image or on its own image.
Simplified 3 level dose comparisons are available for either the high
gradient regions or the prescription dose levels. These type of displays make
it readily apparent just how the dose distribution that is in fact measures as
delivered to the film (representing the actual patient) compare to what is
expected and intended to be given as defined by algorithms and mathematics the
primary planning computer. This
confidence that can be provided by the accuracy and clear presentation of the
VALIDictorianÒ can make the institution of
a new IMRT program easy for the new physicist or it can improve the easy and
confidence in an existing IMRT delivery program. Phone (209) 524-6789 or CNMC at (800) 635-2662 and we can help you establish a new program
or upgrade and existing program.
HIGH
GRADIEENT REGION AND PRESCRIPTION LEVELS
The isodose lines from either image can be overlaid on
the other image or on its own image.
Simplified 3 level dose comparisons are available for either the high
gradient regions or the prescription dose levels. High gradient dose levels are generally in the 50% decrement line
region and so isodose comparison are made at 40, 50 and 60 percent levels to
evaluate the differences in the high dose gradient level (as shown on the
previous image) Differences are also able to be shown near the prescription
level so levels at the prescription level and 5% above and below that Rx level
are able to be presented. These
difference displays are often used to represent the agreement of the measured
dose as delivered to the film (representing the patient) relative to the
planned dose as calculated by the primary computer planning system. To institute this program capability, order
your own VALIDictorianÒ system by calling (209)
524-6789 or CNMC at (800) 635-2662 You can have this capability within hours of taking delivery
of your own
VALIDictorianÒ
OUTPUT
MODULE
Clear
and meaningful displays on the screen are one thing, but the output
capabilities of the VALIDictorianÒ are specifically designed
to provide the necessary paperwork to document the validation. Several output sheets are able to be viewed
before they are printed and the printing is accomplished by a single
command-button click.
ONE:TO:ONE
PLOT OF THE FILM SCAN ISODOSE LINES
The isodose lines from the film scan can be
presented on an exact one to one scale to enable them to be overlaid on a paper
print from the primary planning computer.
This is to enable some sort of overlay comparison even for those primary
planning system that are unable to provide dosemap data. There are utility routines to adjust this
plot to EXACT 1:1 scale. This special
capability of the VALIDictorianÒ allows the comparison of
plans even from treatment planning computers that are older and perhaps limited
in that they may be not able to produce the required DICOM file output or other
compatible output. Again VALIDictorianÒ proves to be most versatile and you too can
have this versatility by purchasing your own VALIDictorianÒ by calling (209) 524-6789 or CNMC at (800) 635-2662
COMPARISON
OF THE IMAGES ON ONE PAGE
The
images of the dosemap, the film scan and the differences between the two as
well as the differences presented as the limits tints can be presented on a
single page.
OVERLAY
DOSE ON FILM or (FILM ON DOSE)
A printer output of the overlay of isodose lines on scan
tints makes it very easy to compare the two images. This type of display makes it very easy and intuitive to
demonstrate the correlation of the two images for various protocols. If you are involved in a protocol requiring
this type of display, the VALIDictorianÒ can provide it as one of
its standard output formats. (209)
524-6789 or CNMC at (800) 635-2662
PROFILE
COMPARISON
Whatever
cross line profile was defined in the VALIDictorianÒ 'COMARE' module, can be presented as hard copy
paper output. This crossplot shows the
profiles that are presented by both the dosemap and the film scan. The same exact coordinates are used by the
VALIDictorianÒ in both images to determine
an equivalent profile in each image.
Further information is provided in the differences plot as also
presented on this page (which is truncated at +and - 25% of the prescription
dose). You may request hard copy
samples of these VALIDictorianÒ output pages from us at
(209) 524-6789 or from CNMC at (800) 635-2662
and we will be happy to send you samples as well as other information
and brochures.
HISTOGRAM
HARD COPY
VALIDictorianÒ presents histograms of the two images and
the differences. These difference
histograms form some of the basis for the artificial intelligence evaluation to
check if the comparison meets user specified criteria.
SUMMMARY
SHEET
A
single page summary evaluation is determined based on user provided limits
criteria. These criteria are used by
the VALIDictorianÒ artificial intelligence
algorithms to make a recommended evaluation and that result is presented as a
report of the validation results.
Again, the VALIDictorianÒ excels in proving to be the
most useful and understanding of the needs of an IMRT validation program by providing
a very useful summary of the results of the validation. If you would like the clarity and
convenience that the VALIDictorianÒ can provide to your IMRT
validation programs, just order your own from us at (209) 524-6789 or from CNMC
at (800) 635-2662. We can help you set
up the entire program as well.
SUMMARY
OF POSSIBLE EVALUATION RESULTS
A
one-page summary of the possible results of the validation is available. This is not intended to be part of a patient
chart, only for your personal information.
UTILITIES
The
VALIDictorianÒ has not forgotten the needs
for the entry of specific data from your own institution and again the
VALIDictorianÒ has been specifically
designed to make this procedure as easy and painless as possible. There are simple to use utilities provided
to enable the entry of the various parameters necessary as defaults in the
validation procedure. Each item is
accessed as a separate option and each option walks you through the entry of your
own parameters and desire acceptability limits. We can help you set up these parameters on your initial
installation and you can be fully functional and knowledgeable in the
procedures in just a few hours. We can
also help you set up your entire IMRT program and recommend the necessary other
details necessary for a competent IMRT program
(209) 524-6789 or (800) 635-2662
PLOTTER
SCALE CALIBRATION
To
make the output also most accurate, a very simple method is provided to enable
you to adjust the printer/plotter output to make it match a 1:1 scale. A plot is made and the measured horizontal
and vertical distances are entered. The
computer calculates the appropriate factors to adjust the output to make it
perfect. Again the VALIDictorianÒ proves to be most understanding of the needs
of an accurate IMRT program in even the most simple things that may be
overlooked in other systems.
+
DEFAULT
ISODOSES TO BE PRESENTED
The
user can specify the default isodose lines and the default colors that are to
be associated with those isodose lines.
In this the VALIDictorianÒ proves to be understanding
of the desires of the users to control the parameters that are used in the
validation procedure. This allows the
user to specify the default isodose lines and the colors by which that those
isodose line will be presented.
HELP SCREEN
When you press the "Help"
menu item from the main startup screen, the following screen will be presented
as a reminder of the procedure that is expected to be used to validate an IMRT
treatment plan delivery. Each of the
items on the screen can be "clicked-on" to activate a more specific
detailed explanation of what is expected and some suggestions as to what might
be a reasonable way to accomplish it.
Superiority
of the VALIDictorian Ò
We
want to be responsive to the needs of the end user and we are available to help
in using these programs and are always responsive to the desires and request of
our users for increased capabilities or new detailed capabilities. The value of the VALIDictorianÒ is improved by the positive feedback and
recommendation of our many loyal users and we want these programs to be
constantly improving to be the best available.
(209) 524-6789 for questions or recommendation of you can order directly
from CNMC at (800) 635-2662
Comments on the Validation
Procedure
The validation is accomplished by
making a comparison of the dose distribution that the compute has determined
should be produced, with a measured distribution that has been determined by using
films exposed to an application of radiation that is identical to that which
the computer determined for the patient application.
If the computer has been correct in
calculation the expected dose distribution, then the scanned films will confirm
that dose distribution.
If the scanned film cannot confirm
the dose distribution that the computer determined should have been delivered,
then there is some error. There are
many sources of possible error and the magnitudes and types of the differences
that are found will determine whether the plan should be applied to the patient
or if there is further concern to be resolved before patient treatment should
commence.
If the validation procedure confirms
the acceptability of the dose distribution in conforming to what is planned and
expected, then the delivery of the radiation treatment may be reasonably
initiated. The complexity of such
treatments will require continuing attention to the accuracy of the patient setup
and careful monitoring of the patient's responses as the treatment
progresses.
Routine treatment field portal
images of some credible form should be acquired, evaluated, accepted by M.D.
signature and saved for documentation.
These portal images may be accomplished by using films or by using
portal imaging devices, but the accurate delivery of the prescribed dose
requires the accurate positioning of the patient.
Besides confirming the dose
distribution, the validati0on procedure also should confirm the actual dose
that is delivered. If the films are
correctly and adequately calibrated, this can be accomplished within a few
percent by using the films acquired for the validation procedures.
As a confirming back-up measurement, it is recommended that
a simple ion chamber measurement be made at the same time that the films are
produced. This is to make it possible
to make an absolute dose comparison.
The absolute dose should be made at a position where the dose gradient
might be expected to be quite flat.
This should be chosen to attempt to minimize the sensitivity of the
measurement to the positioning of the ion chamber. Even so, the ion chamber will integrate the dose over some finite
volume while the computer generally presents the dose at a specific point. For these types of validation procedures the
films may be more appropriate as they are not so sensitive to position and can
be adjusted after the measurement to assure that they are correct.
VALIDATION
PROCEDURE:
preparation
of the phantom:
1) CT
scan the calibration phantom.
2) Transfer the CT scan to the planning
computer.
on
the planning computer:
3) Design the patient treatment plan.
4) Calculate the phantom validation plan.
5) Transfer the validation plan to
VALIDictorianÒ.
6) Prepare the film in the phantom for the
validation procedure.
in
the therapy room
7) Position the phantom on the treatment
delivery machine.
8) Deliver the treatment plan to the
phantom.
9) Measure a calibration point with the ion
chamber (optional)
at
the VALIDictorianÒ computer console:
10) Input the
necessary data files.
11) Align and
adjust the data to validate the results using VALIDictorianÒ.
12) Print the
results and include in the patient records with documentation.
Preparation
of the phantom:
1. CT SCAN THE PHANTOM: Prepare a phantom for use in the validation
procedure. This is accomplished by
using the CT scanner that will be used for the regular patient planning
procedures to scan the calibration phantom that will be used for the validation
procedure.
The phantom
should be carefully placed in the CT scanner for scanning with the alignment
being centered and square to the plane of the CT scans.
2. TRANSFER CT OF PHANTOM TO COMPUTER:
This CT of the validation phantom will then need to be transferred into the
planning computer. It may be saved for
use with many patients and several phantoms may be prepared and archived in a
library of validation phantoms in the treatment planning computer.
Re: Phantom Design:
The phantom
provided with the VALIDictorian system is specifically designed to the needs of
the validation procedures, but other phantoms should be able to be used as well
because if the VALIDictorianÒ system's versatility.
For use with the VALIDictorianÒ, it is not necessary that the phantom be anthropomorphic or
that it match the patient's geometry.
No matter how carefully an anthropomorphic phantom is constructed it
will still not be exactly the same as the patient being treated. Recognizing this, we have designed the
VALIDictorianÔ
to be able to accurately be used a standard phantom as long as the exact same
standard phantom is used for the preparation of the validation dose map by the
computer planning system.
The VALIDictorianÔ phantom is specifically designed to enable the easy
positioning of the films and includes an appropriately placed hole for
inserting the ion-chamber that will be used for absolute dose
determination. Even when an ion chamber
is used, it may be necessary to perform a re-calibration of the ion chamber
that will be used in the validation procedures by intercomparison with an ion
chamber that is used in the actual calibration of the dose delivery machine.
Preparation of the computer generated dose map:
1. PRODUCE THE TREATMENT PLAN: Prepare the
treatment plan that is intended for patient application.
2 PRODUCE THE PHANTOM PLAN: Prepare an
equivalent plan on the same computer using the same beam positions and
orientations and configurations that are intended to be used to treat the
patient. These beams should be applied to the validation phantom. This will produce a dose distribution that
can be compared with the dose distribution generated in the phantom on the film
scan.
ABSOLUTE DOSE: The computer should also
calculate specific dose values at the location where the ion chamber will be
placed. This position should be able to
be seen on the CT scan images imported from the CT scanner.
ALIGNMENT: For alignment purposes,
specific points should be selected for alignment with the film images
later. These points will not
necessarily need the dose calculated at those points, but that may be necessary
for the defining of these alignment points.
The
isocenter will need to be precisely determined and presented and the alignment
points that will be use also need to be specified. These alignment points are generally considered to be the
locations where the laser alignment points that indicate the isocenter will
enter the phantom.
3. TRANSFER PHANTOM PLAN TO VALIDictorianÒ:
The resulting dose map needs to be made available to the VALIDictorianÒ
for use in doing the validation. This
may be accomplished by saving the dose map to a known position of the
computer's network for network access by VALIDictorianÒ
or the dose map may be copied to some sort of a floppy disk, ZIP disk or CD to
accomplish the physical transfer to the VALIDictorianÒ computer.
Produce the validating film scans:
1: INSERT AND MARK THE FILMS: Prepare the
phantom with the films by carefully inserting the correct film type in the
phantom. This film should be marked with alignment points that will enable the
resulting film image to be related to the treatment delivery machine's
isocenter, size scale and orientation.
It is recommended that "pin-pricks" be used to
mark the positions where the alignment positioning lasers will intersect the
film in the phantom when properly set-up in treatment position. This can be done ahead of time to minimize
the time that the treatment delivery machine schedule needs to be
interrupted.
At most, no more time than would normally be required to
treat that same patient will be needed.
This can be scheduled the day before the patient starts and can be
scheduled in the patient's normal treatment time slot. This will be a chance for the treatment
delivery procedure to be practiced to assure that there will be minimal
problems when the patient is actually being set-up and treated.
2. POSITION PHANTOM AND FILM ON THE TREATMENT
TABLE: The phantom with the film is then very carefully positioned on the
therapy machine table. The phantom
should be precisely aligned with the laser system to ensure that the phantom is
accurately aligned to the laser alignment system. This is necessary to assure that the film will represent the dose
generated by the computer.
This careful positioning must be done with the same care and
accuracy that will later be used to position the patient for treatment
delivery. Consequently the validation
procedure also can be seen to be evaluating the set-up personnel's ability to
position something (patient or phantom) for treatment.
3. EXPOSE THE FILM: With the film carefully inserted in the
phantom and marked with the alignment points and with phantom correctly aligned
on the treatment table, then deliver the exact same dose to that phantom as
would be delivered to the patient if the patient were being treated instead of
the phantom being irradiated. This is
the film that will be compared to the computer generated dose map for the
validation procedure.
4. EXPOSE A CALIBRATION ASSURANCE FILM: This step may not always be necessary as you
become more confident in the film calibration procedure. Initially it would be desirable to expose a
film for calibration purposes with each validation film scan. This calibration film consists of a film
done as described in the "Utilities" section under Routine
Calibrations.
5. DEVELOP THE FILMS: Use the normal film development procedures
and do it promptly to avoid any damage to the films and any excessive light
leakage through the pin-prick holes (the holes may be covered with masking tape
to minimize light leakage).
Validating the results
You now have all the requires pieces of the puzzle that are
necessary to accomplish the validation and solve the question of whether or not
the dosimetry is correct and if the plan able to be delivered as expected by
the computer.
You may think that this is not necessary to be done on every
plan; however, the use of complex plans opens the door to complex problems. The requirement of many systems to function
correctly increases the possibility that just one small piece of the treatment
delivery chain may break and fail to deliver a correct treatment. The results could be devastating.
The VALIDictorianÒ procedure is intended to simplify the validating of the
dose delivery method from planning to delivery.
If the VALIDictorianÒ film scans indicate a satisfactory dose level and dose distribution,
the user can be at least a little more assured that nowhere in the complex
procedure from planning to delivery has anything gone drastically wrong. It's highly unlikely that a satisfactory
validation results can be produced if any of many possible occurrences have
failed to be correct as planned.
If the VALIDictorianÒ procedure indicates there is a problem, there are many
sources for the discrepancy. The
physicist and dosimetrist will have to be involved in determining the source of
the discrepancy and rectifying it before repeating the validation
procedure. Possible sources of error
include the following:
The film calibration
Wrong film used.
Dose
delivered is outside of dose range of film.
The phantom setup
Wrong
phantom.
Wrong positioning.
The computer
Wrong plan,
wrong phantom calculated
Bad computer calculation algorithms (It's possible)
The delivery system
Wrong plan
in delivery system
MLC drives not functioning correctly
Calibration
cGy/MU in error
Isocenter
accuracy not as in planning system
Validatation system
Wrong files
imported.
Wrong
calibration curves used
Not
correctly realigned
Other sources of validation failure
There are always other
possibilities, use your brains.
Calibrate the
films:
At this point,
we will assume that the H-D curves for the film that will be used has already
been accomplished and the films are thus "calibrated". These H-D calibration curves should be
available in the VALIDictorianÒ data files for use by the system.
A complete
discussion and explanation of this procedure is included in a special section
in the discussion of the "Utilities".
VALIDictorianÒ
Advantages of Film over
Diode Array
1) Film has higher spatial
resolution near critical structures:
The VALIDictorianÒ
film system has a higher spatial resolution than a diode array. One of the disadvantages of a diode array is
the spatial resolution of the diode array.
For a typical 22x22 cm. measurement plane there may be approximately 445
measurement points. For film there are
essentially an unlimited number of measurement points, but, for practical
purposes, measurement could be easily derived on a millimeter spacing resulting
in 48,800 measuring points in an equivalent 22x22 area (over 100 times as many
as for a diode array) and the film area is not limited to only 22x22 cm. This high resolution allows the film to more
accurately measure regions of high dose gradient, which occur in IMRT fields
and are of special critical interest in IMRT treatments. A diode array may be accurate in areas of
low dose gradient, but critical structures are never in such areas and are
generally exactly at those critical high dose gradient areas. The VALIDictorianÒ
film resolution is unrivaled for determining the dose in such critical areas of
high dose gradient near sensitive structures.
These areas of high dose gradient are the exact areas where IMRT
validation is most critical and where diodes are least able to do the job adequately.
Does the diode array have pretty pictures? Maybe. Does it have accurate results
in critical areas? Questionable.
2) Film uses the exact treatment
showing the true results of the IMRT plan:
Diode array measurements may
be barely adequate to show the correlation of the individual fields, but what
is of even greater significance is the composite result of adding all the IMRT
fields. Each IMRT field may consist of
seemingly obscure, strange IMRT dose distributions, which are somehow expected
to combine in the patient to produce a uniform dose distribution in the desired
regions. Analyzing each individual
field will not show the validity of the combination and is not able to evaluate
the composite as being correct. This is
perhaps the most important aspect where the VALIDictorianÒ
IMRT validation excels and where the diode array cannot validate the composite
result as being as correct or as expected.
3 Film is not limited, as is a
diode array, to a straight down orientation:
A major deficiency of a
diode array it its limitation to measurements of a single beam in a single,
straight down orientation. The diode array does not have the ability to measure
true composite dose distributions with the beams in their intended treatment
angles. The diode array requires beam
irradiation normal to the surface of the diode array detector. Furthermore, each of the beams will have to
be individually measured so a 7 field technique will require 7 separate set ups
and exposures, perhaps none of which are in the patient treatment angle
orientation. This requires extra time
to accomplish.
4 Film requires a single
measurement for faster more efficient measurement.
VALIDictorianÒ
evaluation technique for composite IMRT dose distributions has the added
advantage of requiring only a single film in the plane of the dose distribution
being validated. The diode array will
require a measurement and irradiation for each beam that will be used. Thus the use of film generally reduces the
overall time required for the validation procedure. This will tend to decrease the workload on the physicist in
accomplishing the otherwise complex, and generally time consuming, task of IMRT
validation.
5 Film can provide hard copy
for archiving:
Furthermore, the films used
by VALIDictorianÒ can provide hard copy evidence of the
appropriateness and accuracy and quality of the treatment. This information can be saved for later
evaluation or for archiving for record keeping purposes. Diode array reading disappear when the next
reading is taken (Perhaps a desirable thing if you are unsure of what you are
doing).
6) Film evaluates the entire
treatment technique as it will be given to the patient:
The use of the film in the
VALIDictorianÒ also allows the complete evaluation of the
treatment delivery, including the setup of the patient and the alignment of the
isocenter. It enables an evaluation of
the entire treatment delivery as it uses the exact same monitor unit settings,
beam angles, MLC movements and delivery procedure that will be delivered to the
patient. The use of the diode array is
measuring something that is not really what is being delivered to the patient
at all. The use of film evaluates the
entire treatment as it will be delivered to the patient. If the treatment is delivered to the phantom
with the same care and attention to detail as the treatment is delivered to the
patient, then the film procedure even evaluates the ability of those who are
delivering the treatment to carefully setup the patient and the validation
phantom to the exacting parameters that are required for the IMRT
treatment. (This also decrease the
workload on the physicist)
7) Film has the ability to do
other routine quality assurance procedures:
The VALIDictorianÒ
is also able to use films for routine quality assurance for MLC and single open
fields. A single film exposure gives
in-plane and cross-plane flatness and symmetry and has the advantage of being
able to evaluate the flatness and symmetry across the entire face of the beam
and not just across the primary axes.
Film can also do percent depth dose measurements and profiles at depth
with and without wedges. The
VALIDictorianÒ also has the ability to double-check the
monitor unit calculation for simple fields and irregular fields as well as for
complex MLC and dynamic MLC fields.
The VALIDictorianÒ validation system is
superior to a simple diode array for speed, ease of use, resolution,
effectiveness and versatility!
The following suggested
"check list" may prove helpful in establishing your own IMRT delivery
preparation procedure:
There are many steps to
successfully planning and preparing a patient for an IMRT treatment. Many people may be involved with this
procedure and several items cannot be accomplished until the preceding
requirement has been completed. To
avoid delays and ambiguities of the status of a patient's IMRT plan, this
checklist details some of the basic steps and helps the procedure proceed in an
orderly fashion. Everyone will know
what has been accomplished and what is yet needed and will provide an
understanding of the interrelationship of all the parties and steps involved in
initiating a successful IMRT treatment.
From initial CT scan to actually starting the patient on the machine may
take as much as a full week.
_____(checklist follows)_____
IMRT Check
List
(to be initialed and dated by the person who does the item)
CT Scanner
[ ] Patient Scanned in CT Scanner, date : ____________________
[ ] Tumor and Critical Volumes Defined by M.D.
Planning Computer:
[ ] Treatment Plan Produced
[ ] Treatment Plan Accepted by M.D.
[ ] Validation Plan Produced
[ ] Treatment Plan Setup Control Sent to
Therapy Unit
[ ] Validation Plan Dosemap Sent to
VALIDictorianÒ
Validation Measurements:
[ ] Film Scan Produced on Therapy Unit by
Machine Radiotherapists
[ ] Ion Chamber Calibration Reading Made by
Physics
VALIDictorianÒ:
[ ] Dose Map Imported
[ ] Film Scan Imported
[ ] Alignment Points Defined and Images
Aligned
[ ] Known Dose Points Defined and Images
Correlated
[ ] Differences Images Created
[ ] Comparisons Made and Results Printed
Acceptance:
[ ] Plan and Validation Discussed in Chart
Rounds and Accepted by M.D.
[ ] Patient Started on Therapy Machine, date: __________________
_____(end of
"Checklist) ____
Superiority of the
VALIDictorianÒ
We recognize
our responsibility for the accuracy and quality of our programs and to the
needs and benefits of the patients whose treatments will be validated (or
rejected) by these programs. We further want to be responsive to the needs
of all our end users and we are available to help in using these programs and
are always responsive to the desires and request of our users for increased
capabilities or new detailed capabilities.
The value and superiority of the VALIDictorianÒ is improved by the positive feedback and by
the recommendations of our many loyal users and we want these programs to be
constantly improving to be the best available for the greatest benefit of all our
users and their patients.
Every day you wait, is yet another
day that you do not have the capabilities of the VALIDictorianÒ that you need to give you
the necessary accuracy and real confidence you need to take full advantage of
an IMRT program in your facility
You need to wait no longer
For hardware and software specifications and
available options as well as other information about the VALIDictorianÒ system, its various configurations and their
costs and to determine when you might be able to be placed on the delivery
schedule, you may contact us at:
Medicalibration
(209) 524-6789
or at
CNMC: (800) 635-2662
or Sales@VALIDictorian.com
Thank
you for viewing our site.