MIRS (Module Integrated Radiotherapy System) is a powerful modular high technology system that allows three-dimensional planning for several radiation treatment modalities such as Conformal Radiation Therapy (3D-CRT), Electron Beam Radiation Therapy (EBRT), Radiosurgery with Linear Accelerators and Intensity Modulated Radiation Therapy (IMRT).

As all products developed by Nuclemed S.A., MIRS runs on a PC under Windows Operating System, ensuring an economic, scalable and easy to maintain hardware platform.

MIRS adapts virtually to any stereotactic frame and fiducial system.

MIRS has an exceptionally versatile and user friendly interface. The user can customize screens (WorkSpaces) and save preferences for future use.

MIRS includes a Patients Database, which allows to administrate the Patients being Planned and all Cases linked to them.

MIRS allows importing and registering sets of images in any primary orientation, axial, sagital or coronal.

MIRS allows automatic intermodality medical image registration. Besides MRI and CT studies, Functional MRI, PET and Angiographic images can be imported and registered.

MIRS allows registering sets of images without fiducials with manual and automatic tools.

MIRS supports five different modes of fusions between image studies.

MIRS allows region definition and contouring in windows containing image reconstructions in arbitrary orientations, axial, sagital, coronal and even oblique planes.

MIRS has a security system protected with passwords with several hierarchy access levels.

MIRS runs with two different environments so it is possible to plan simultaneously two treatments. In this way the user can take profit of calculation time in one environment to edit or enter data in the other environment for other patient.

MIRS Works with Background Dosimetrical Calculations, which allows to progress with treatment planning while system performs dosimetrical calculations administrating and updating dosimetry as raditaion beams ar added or modified, thus optimizing case planning times.

MIRS has an advanced print manager that allows the user to customize treatment reports.

Multiple image studies of either MRI or CT scans can be loaded. MIRS supports importing images in DICOM 3.0 format. If images from the scanner are in other format, they can be imported anyway with the RAW format option. If you have to scan images right from the film you can import them using the BMP/JPG format option, so you will never be frustrated.

Imported sets of images can have any primary orientation axial, sagital or coronal.

Functional MRI and PET images are accepted for image registration. MIRS supports importing images in Analyze format.

MIRS accepts importing and registering multiframe image studies of angiography changing injection time between consecutive frames. The forward registering method adopted allows minimizing registering error even in cases when the reference box and fiducials is rotated or the alignment is poor.

MIRS has incorporated a Co-Registration option which allows registering sets of images taken without a stereotactic frame and fiducials. Co-Registration can be performed manually or automatically launching an algorithm that minimizes mutual information. This algorithm works to co-register intramodality and even intermodality sets of images. You will find this feature really useful to follow up patients or when you can not perform all the studies on the same day with the stereotactic frame in place or when you have to perform different image modalities in different facilities. In addition the stereotactic frame may produce artefacts in some image modalities.

MIRS supports a variety of fusion modes between studies:

• Mixing: The user can adjust the level of mixing between studies.
• Maximum value: The pixel with the maximum value is chosen for displaying.
• Minimum value: The pixel with the minimum value is chosen for displaying.
• Subtraction: Subtraction of pixels values is displayed.
• Superimpose: A segmented study can be superimpose on other study.

Image engineering of great agility and versatility with improved WorkSpace management and Visualization Options.

The user can define number, size, type and position of images to be displayed. Preferences can be stored for future use. A different image study or fusion can be assigned to each window on the WorkSpace.

Image types in MIRS are:

• Sagital, coronal or axial according to the stereotactic frame orientation.
• Reconstructions along and orthogonal to a beam and an arbitrary vector (ViewVectors).
• DRR.
• Bev.
• 3D Views.
• Dose-Volume Histograms.
• Dose Profiles along a Line.
• Projection view according to an associated X-Ray Projection Study.

A navigation point can be kept in common for all image windows to allow automatic correlation and navigation throughout the anatomy.

Exhibits a Room View and a Patient Scheme in every image for better comprehension.

Interactive real time Pan, Zoom, Brightness and Contrast functions.

A WorkSpace can contain one or more active 3D views simultaneously.

Besides regions and beams, a 3D view incorporates a segmented representation of the image study or fusion.

Segmentation level can be adjusted by the user to visualize only the regions of interest. Observer's distance can also be adjusted by the user. Reconstruction can be limited by planes parallel to coordinate planes which are also user defined.

A variety of display options is available for 3D objects.

Any image or the complete WorkSpace can be printed or stored in BMP/JPG format.

Regions of interest can be defined and drawn manually or using segmentation tools.

Segmentation tools allow definition of highly irregular regions as tumours or even blood vessels.

Unlike other technologies, MIRS allows editing and drawing of regions simultaneously on images of different orientations not restricted to axial images.

Complex regions can be created from other defined regions using operators (And, Or, XOR, etc…).

MIRS provides special tools such as contour interpolation and automargin or 2D and 3D expansion to simplify contouring of regions of interest and bolus definition.

A variety of options is available for region display in two and three dimensions.

MIRS ofers an “Alarm System” for dosimetrical controls, which allows user to configure, for each region individually, situations in which the system will warn that the actual dosimetry meet one or more of the restriction conditions

MIRS can use multiple matrices for high resolution calculation at regions of special interest. Matrix resolution can be change by the user editing matrix size.

MIRS can take density from CT numbers or density can be defined for each region. The density of a zone can be arbitrarily set, for example for organs with contrast media.

MIRS allows multiple treatment plans which can be competitive plans to be compared against each other or can be combined in a more complex treatment plan.

MIRS offers the possibility of combining different treatment modalities such as 3D-Conformal Radiation Therapy, Intensity Modulated Radiation Therapy, Electron Beams and Radiosurgery with pendular beams and conic collimators.

The beam set up window allows automatic isocenter location at the centre of any region defined.

Blocks and beam apertures can be automatically or manually defined to spare or treat a given region.

Beam parameters can be set graphically with the mouse or can be enter with the keyboard.

Beam isocenters can be modified individually or all together.

Axial, sagital and coronal Image reconstruction sets can be obtained to visualize patient anatomy and dose distributions. Reconstruction in planes orthogonal to beam axis and arbitrary vectors user defined (viewvectors) is also possible. A navigation point allows automatic correlation between different views making possible the navigation throughout patient's anatomy in image reconstruction sets of different orientation.

Dose distributions can be displayed as isodose lines or dosewash.

The user may compare different plans watching simultaneously the dose distributions for the same set of images in different windows for different plans, all of them correlated by the navigation point.

Comparisons can be made clearer displaying in dosewash the difference in dose distribution for two alternative treatment plans.

Points of interest can be defined to monitor the dose. Dose profiles can be plotted between any two points.

Cumulative and differential DVH can be calculated for regions of interest. Dose Volume Histogram window shows not only the DVH itself, but also the volume, maximum, mean and minimum dose for each region of interest. DVH from different plans can be displayed in the same window to allow direct comparison.

Three dimensional windows show regions, isodose surfaces, segmented regions and beams. The user can select the way the object is displayed from a variety of options: translucent, solid, wire, mesh, etc. Adequate coverage of the target sparing of normal tissue can be easily evaluated with these tools.

MIRS calculation algorithms differs according to the module, applications and options. The Module for Radiosurgery with conic collimators uses an algorithm based on a look up table. This algorithm has proved to be accurate enough in absence of heterogeneities and for the small circular fields involved in this application. On the other hand it is fast enough to be employed in multiple arc beam calculations.

Beam commissioning is made through a user friendly graphic interface combined with appropriate tools specially designed to compare experimental and calculated photon dose distributions. A relatively small set of experimental data is enough for commissioning and verification purposes. Experimental data can be imported from automatic phantoms and dose distribution in the phantom can be calculated using CVSP. By iteratively changing beam parameters, the user models the beam and fits the experimental data.

MIRS version 4.0 features IMRT module.
This new function introduces an innovating and fast inverse planning algorithm.

It includes 3 different objective functions/constraints for each region: max/min dose, DVH curve points and/or EUD (“Equivalent Uniform Dose”).

Combination of them with different weights is also possible. “Beamlet” size is user defined being square or rectangular.

Different beams may also have different beamlet size.

Beam modulation can be done by MLC segmentation (step and shoot) or by solid compensation filters. For this case several materials can be commissioned to obtain an optimized filter.

QA specific tools allow the visualization and export of the total beam fluence or the dose at a cubic phantom at a given depth.

Solid IMRT filters can be visualized in a 3D view or by a thickness map. Filters can be exported in formats compatible with CNC milling machines.

This example shows spine preservation employing only max/min objective function. This calculation is done in approximate 1 minute depending on computer speed and memory (a 3.2 Ghz Pentium IV processor with 2 Gb RAM was employed in this case).

A faster calculation algorithm and a patient data base were also implemented in this version.

MIRS V4.0 –Electron Beam Solution
This new function introduces the capability to plan Electron Beam radiotherapy treatments.

Easy electron beam commissioning.

Multiple electron cones free configuration.

Conformal electron therapy supported.

Manual or automatic conformation design.

Rotational electron therapy supported.

MIRS offers advanced tools to design treatment reports. The user can customize reports according to his preferences including treatment protocol, dosimetric information, graphics as Dose Volume Histograms, Dose profiles, Bev and DRR images and 2D or 3D image reconstructions.