New in V5.2 - IMRT analysis plot called Proportion Passing Plot– plots the proportion passing for a range of subtraction tolerances.

New in V5.2 - Case files can be saved from IMRT analysis toolbars - It is not necessary to use RunQueueA to make a Case file. Layouts now remember image divider positions

This routine combines the dose difference measurement with the distance to agreement (DTA) to provide one metric for each pixel. Gamma values greater than one indicate failure of both criteria. The calculation of gamma throughout the measured dose distribution provides a presentation that quantitatively indicates the delivery accuracy relative to the acceptance tolerances. The Gamma Function can be calculated for one or two dimensional dose distributions. You can also look at Gamma Pass/Fail plots and Gamma Histograms. This routine is based on a technique by Lowe, Harms, Mutic and Purdy of Mallinckrodt Institute.

Low, Harms, Mutic, Purcy, "A Technique for the quantitative evaluation of dose distributions," Medical Physics, Vol 25, May 1998, 656-661.Low, Dempsey, Mutic, “Evaluation of the gamma dose distribution comparison method”, Medical Physics, Vol. 30, #9, September 2003, 2455-2464.

DTA is the distance between a measured dose value and the nearest point in the calculated dose distribution that contains the same dose. In this routine you set the tolerance (+/- %) and the maximum search area (in cm) and the calculations are performed. This important tool is critical to analyzing IMRT deliveries in the high gradient regions. You can also view DTA Pass/Fail, Histogram and 3D Surface Images.

After you bring in any two images and register them, this routine will plot a profile through both images at the same spatial location. Both profiles may be plotted with a Difference and/or 1D Gamma plot. Histograms are also provided to illustrate the difference between profiles. Use arrow keys to move Profiles to give you greater control over fine line positions than you have with a mouse.

Bring in a plan from a TPS and a film irradiated to that plan, and compare them using Van Dyk's criteria, the most critical of the tests for an IMRT system because it verifies the patient exposure on a pixel by pixel basis. You can view histograms or pixel images for any of the gradiant/dose combinations.

Van Dyk, J., Barnett, R., Cygler, J, and Shragge, P., "Commissioning and Quality Assurance of Treatment Planning Computers," Int. Journal Radiation Oncology, Biol. Phys., 26, pp 261-273, 1003.

Use this routine to see the exact dose differences, on a pixel-by-pixel basis, between two images. The output of this routine provides a difference image and a difference histogram. You can set an acceptable threshold (e.g. + -3%) and the software will tabulate the number and percent of pixels exceeding your tolerance in red, and cold pixels exceeding your tolerance in blue. Then change your threshold and watch as the analysis is recalculated in an instant. You can also view a Subtraction Histogram and/or Subtraction 3D Surface Plots. This routine gives you the ability to compare step and shoot to sliding window techniques; compare treatment with different numbers of beams; compare plans delivered at different dose rates; or compare plans from two different types of treatment planning systems.

The composite analysis plot combines the subtraction and DTA Pass/Fail plots into one display. The plot shows the areas that pass and/or fail the DTA and Dose Difference Tolerances.

The plot is color coded as follows:

• Green: Pixels that pass both the current DTA and current Dose Difference tolerances.
• Blue: Pixels that pass the current DTA tolerance and fail the current Dose Difference tolerance.
• Yellow: Pixels that fail the current DTA tolerance and pass the current Dose Diff. tolerance.
• Red: Pixels that fail both the current DTA and current Dose Difference tolerances.

The composite analysis is a more stringent test than the gamma analysis as the pixels have to pass each tolerance independently. Pixels that fail the gamma analysis will also fail the composite analysis. Pixels that fail the composite analysis may not fail the gamma analysis.

This routine brings in any two dose images and then performs isodose contouring on either image or the overlay. It is often used to determine if the execution of the plan matches the plan in the TPS. All IMRT routines include a feature to control dose thresholding to exclude pixels below your specified level as well as an improved isodose editor with store and recall for multiple configurations.

This routine helps you analyze multiple complex treatments which much be administered separately (in order to avoid a critical organ, boost the dose to a portion of the tumor, etc.). It allows you to add the dose of two images and view an image that is the sum or an Isodose image of the sum of those images.

The IGRT Alignment routine is used to measure the spatial misalignment between the IGRT imaging system and the treatment beam.

“Output, Energy and Imaging-to-Treatment Alignment for a Helical Tomotherapy System". S.L. Mahan, D.J. Chase, and C.R. Ramsey, AAPM 44th Annual Meeting; Med Phys 31 (6), 2005.

This routine interfaces with your TPS template or a phantom to be used as a template. When you generate a template file using the Register Template routines, the registration points for the dose map will be automatically moved to the specified point locations in your plan. This means that you will only have to specify the location of the fiducial markers (pin pricks for the template) in the film image. This technique can dramatically increase accuracy and save quite a bit of time. For your convenience, RIT has included several sample template files that correspond to commercially available phantoms.

This routine is an automated correction for small errors in the image registration that result from situations such as large TPS pixels, positions of QA equipment, selection of registration points or other causes. You pick an initial set of points that are "close" to the optimal registration points and the Automatic Fine Tune routine will optimize the point locations for a best fit between the images.

This new function is designed specifically for Tomotherapy users. It allows you to rotate an image without auto cropping it.

RIT113 offers 4 powerful options for registration:

1. Manual
2. Template
3. Image Center
4. Fully Automatic