LINUX: Our software products are now available on both PC-Linux systems and SGI-IRIX systems. Software and manuals can be downloaded from our website at www.mathresolutions.com. You need only submit a form for a trial
license. Porting to Micro-Soft Windows remains a possibility in the future.
RtDosePlan: FDA 510(k) clearance has just been obtained for this external beam program for x-rays only. For customers still running Render-Plan version 2.72b and who otherwise need multi-leaf support, RtDosePlan will be the answer for you. The program was developed initially to specifically add support for multi-leaf collimators, complementing your existing planning system.
We have developed forward-planning techniques similar to the work at Jefferson Medical College (Med. Phys. 27(9) Sept. 2000, pp. 2093-2099). For example, beams may be generated which conform to a prostate target at selected gantry angle intervals with a selected margin, then beams may be generated with the projection of other outlined regions of interest subtracted. Dose constraints may be stated for target and organ’s at risk. Four algorithms are provided to help solve for the weights of these beams to achieve the target dose and minimize the dose to other structures: (1) linear programming, (2) the Cimmino algorithm (see above cited reference), (3) a down hill search, and (4) simulated annealing. Linear programming has both linear constraints and a linear objective function. Plans can be achieved by iteratively moving constraint values, such as lowering the constaint for points outside of the target. Constraints are strictly enforced. The Cimmino algorithm has constraints but does not have an objective function. The down hill search and simulated annealing algorithms only have an objective function, constraints are folded in with penalty values for violated constraints.
The strategies for using each of the above algorithms differ. The end result is the assignment of weight (actually, monitor units) to beams. These tools simply facilitate the achievement of desirable plans, and may qualify for the IMRT treatment planning charge in some cases.
As a works in progress we have coded up an inverse planning algorithm, where by inverse planning we mean subdividing a field into pixels and solving for the intensity of each pixel separately. However, treatment delivery will require a leaf sequencer or compensators, and we will need to apply with the FDA for clearance to provide this as a clinical tool. We would be interested in pursuing this if we find a center interested in this approach. However, we believe that forward planning has the potential to avoid the large monitor unit inefficiencies often associated with inverse planning and an MLC.
For Render-Plan users, your existing beam data can be copied with a utility into our format. A report generator tests the central axis dose against your measured data. You only need to compare a few isodose plots to confirm the planning system. This program will support the multi-leaf collimator with wedges and compute dose volume histograms.
RtDosePlan uses the same pencil beam algorithm that Dosimetry Check below uses. In addition, there is a two part source model which improves the beam profile fit in the shoulder and penumbra regions and models the exchange factor. Additional beam scans are needed to fit this model; profiles at depth are needed for a small, medium, and large field size. A distinct advantage of the pencil beam algorithm is that the artificial division of dose into a primary component and scatter component does not occur as is required in scatter air ratio integration. Here the phantom scatter component is computed and divided into the output factor to obtain the in air collimator scatter factor.
We are currently installing this software at one clinical site. If you are interested please email us. We will soon make the software available for download from our website, so that you can demonstrate the software in your own facility.
Figure 1: Beam's eye view of treatment volume with multi-leaf and symbol indicating direction of the wedge.
Menus: The program uses a graphical interface but organizes the interface into toolbars and pulldown menus. The toolbar across the top of the main window is swapped out as you select different general functions. Specific functions are supported in popups. This makes the system easy to navigate, just as Render Plan was.
Our other products cleared for
distribution:
Dosimetry Check: An innovative approach for quality control for IMRT and conventional radiation therapy. This method eliminates the need to measure dose in a phantom. Instead the films you may already be taking are imported into the system and used to compute the dose to compare to the planning system. Any mistake in the setup of the accelerator accessories or monitor units will show up in the resultant dose distribution.
Figure 2: Isodose curves (green) compared to Dosimetry Check (magenta).
The measured beam films are used as input for each beam calculation, rather then model the field based on the accessories in the beam as done by a planning system.
Dosimetry Check should save you time in doing QA for IMRT. You have to make calibrated images of each treatment field, digitize these images if using film, and optionally download the plan in RTOG format to Dosimetry Check. Within minutes you will then have a confirming dose calculation that is based on the measured field intensities.
We are currently working with the University of Maryland Medical Center in evaluating and implementing this approach in their department. We have demonstrated that if using film, using 3 mm of copper to shield the film from contamination electrons produces superior results (as was suggested in Med. Phys. Vol. 29(8), Aug. 2002, page 1849).
MillComp: An advanced program that can make compensators on a milling machine. This can be used to accomplish IMRT without a multi-leaf. A milling machine can be purchased for a fraction of the cost of a new accelerator.
Radiological Image Display System: An all purpose system for general viewing and solid modeling of CT and MRI images with image fusion and generic support for stereotactic frames. Our above products are built on top of this platform.
C++ Library: We can make our library available for in house projects.
Email
us at support@mathresolutions.com.
Math Resolutions, LLC
5975 Gales Lane
Columbia, MD 21045
(410) 997-9578