This tutorial will guide you through a complete image-based treatment simulation.
The case involves a rather small, posterior, choroidal melanoma located adjacent to the macula in a left eye. This case was selected for the tutorial because it utilizes and benefits from many of Plaque Simulator's technologies. You will gain experience:
Please familiarize yourself with the basics of image based planning for eye plaques by following the links below before proceeding with this tutorial.
Plaque Simulator fuses images and measurements derived from CT (or MR), fundus camera photographs and ultrasound studies to build a three dimensional model of each patient's eye and tumor. A simulation session begins by preparing these images for import into Plaque Simulator.
After the images have been prepared, they will be imported into Plaque Simulator, typically as .jpg files, and calibrated. A 3D model of the eye will be created and the tumor location and altitude entered. Please review these links before proceeding with this tutorial.
Full size versions of the screen captures in this tutorial can be viewed by simply clicking on the pictures. Use the 'back' button of your browser to return to the tutorial after downloading the full size picture.
Creating new patients is simplified by adding a New Folder button to the OSX Finder's toolbar. You only need to do this once, for example, the very first time you create a patient folder. All OSX Finder windows will thereafter follow this configuration.
To customize the Finder toolbar, open the toolbar favorites sheet by selecting Customize Toolbar... from either the Finder's View menu:
or from the contextual menu which is accessed by Control-clicking within the toolbar.
Drag a New Folder button to the Finder's toolbar. This example illustrates the toolbar favorites sheet using the Current Patients folder, which is located in your Plaque Simulator Patients folder, as the backdrop. Click the Done button to exit the sheet.
In the toolbar of the Current Patients folder click the New Folder button and a new untitled folder will be created.
Change the name of the untitled folder to the patient's name or whatever is appropriate to the circumstance, such as My Tutorial if you are recreating this tutorial.
Drag all of the images you have prepared (and named using the PS6 naming conventions) into the newly created patient folder.
The sample images used in this tutorial can be found in Plaque Simulator Folder/Plaque Simulator Data/(Hidden Support Files)/(Tutorial Images)/PS6/Posterior Tutorial. To follow this tutorial, duplicate the Posterior Tutorial images and drag the duplicate files to the newly created patient folder My Tutorial.
Depending upon how you duplicate the files, the word 'copy' might be added to the duplicate file names. For example, using the OSX Finder File menu's Duplicate item, or its keyboard shortcut command-D, to duplicate the files, 'US1.jpg' will be duplicated as 'US1 copy.jpg'.
Once the duplicates are relocated to the new My Tutorial folder you can remove the word 'copy' from the file names.
Alternatively, if you drag all the image files to a different disk drive or a USB memory stick, they will be copied retaining the original file names, and you can then drag the copies back from the other drive into the new My Tutorial folder.
From the File menu:
From the Plan menu:
If the Image window is not visible or frontmost, make it the frontmost window by clicking the cursor in its window or by selecting Images from the Window menu (in the menu bar at the top of the screen).
In the Image window
In the Retinal Diagram window
The objective of this step is to verify that the tumor shape, size and location as digitized from the fundus collage in the Retinal Diagram window is consistant with the tumor as it appears in the MPR images. Cross-sections of the tumor in the meridian and coronal dosimetry planes are tinted brown. The brown tinted regions should closely overlay the tumor in the MPR images. If the model and MPR do not overlay, further refinement of the model using the Image window fundus and eye modeling tools, and/or redigitization of the tumor base may be necessary.
In the Planar Dosimetry window
Meridian pane active
Coronal pane active
In the Plaque Loading window
From the Plaque menu select Plaque Files.
From the Plaque Files menu select the EP917P file.
The 'P' at the end of the file name EP917P indicates that this file includes an embedded picture of the face of the plaque.
The EP917 plaque was selected because:
In the Retinal Diagram window:
1. Auto-centered, eyelets balanced
2. Rotating the plaque CW (the red arrow points to the CW rotation control) results in a collision of the wings of the notch with the myelin sheath surrounding the optic nerve. The region of collision is highlighted with a red tint. This orientation of the plaque would destabilize the posterior edge and put pressure on the nerve.
3. Rotating the plaque a few degrees CCW (the red arrow points to the CCW rotation control) results in a more symmetric fit of the wings of the notch to the myelin sheath surrounding the optic nerve. Although the suture eyelets are no longer equidistant from the limbus, this is the best choice of plaque orientation because the notch and nerve will help stabilize the posterior edge of the plaque.
In the Prescription window we will set the prescription (Rx) dose, the Rx point, dose calculation modifiers, and the implant and removal dates and times.
Note: subsequent planning activities are simplified by establishing the Rx at this stage of the planning process, but the Rx can be revised at any time.
When the EP917P plaque file was opened, the dose calculation modifiers in the Prescription window's toolbar were automatically set to:
For this tutorial, we will begin with a Rx of 85 Gy to the tumor apex to be delivered in 168 hours (1 week) with the implant scheduled for 10 AM on March 10, 2014.
Organize your windows so the Plaque window and the Retinal Diagram window are both visible alongside one another.
In the Retinal Diagram, the source placeholders change from brown to the color of the inventory sources (e.g. cyan) to indicate that they are occupied.
In the Plaque window, with the Retinal Diagram window visible alongside.
Note: in the Plaque window, the cursor changes its appearance to indicate when you are directly over a slot's source placeholder and can load or unload it by clicking.
In the Retinal Diagram, the 2 source placeholders near the notch change from the color of the inventory sources (e.g. cyan) back to brown to indicate that they are now unoccupied.
1. In the Prescription (Rx) window
2. In the Implant Calculator window
The 'P1 Central AXis table' now lists the dose at the Rx point (tumor #1 apex at 2.2 mm) as 85 Gy and the background color has changed from red to green indicating the Rx has been fulfilled.
The sources in the plaque are now 0.79 mCi at the time of implant.
In the Isodose window
From the Dosimetry menu:
In the RDAH Document window
In the Prescription (Rx) window
The 'P1 Central AXis table' now lists the dose at the Rx point (Tumor 1 TAX inner+4.5 mm) as 85 Gy and the background color has changed from red to green indicating the Rx has been fulfilled.
The sources in the plaque are now 1.35 mCi at the time of implant.
In the Patient Setup window
The Treatment Plan is a 5 page document that summarizes the entire simulation. Page 1 provides a table of patient identifiers, date & time of treatment, some radionuclide, plaque and tumor properties, an optional photo ID of the patient, a facial view of the plaque and a miniature retinal diagram showing tumor location.
On page 2 there is a table of point dose calculations along the central axis of the plaque (or tumor), at the prescription point, lens, macula, etc..., and optional thumbnails of the fundus image and/or a surgical guidance picture illustrating the meridian planes in relationship to the iris.
Page 3 of the treatment plan contains thumbnails of the CT or MR images used to model the eye.
Page 4 of the treatment plan contains thumbnails of the ultrasound images used to measure or model the tumor dome.
Page 5 of the treatment plan lists institutional and treatment planning contact information with options for a radiation safety survey form and/or the user customizable picture.
The Loading Diagram document is a "road map" to the plaque. Everything needed to order or manufacture the seeds and assemble the plaque is in this document.
The Retinal Diagram document is a VERY useful "road map" to have in hand during surgery because it illustrates the tumor and plaque location, muscle insertion regions, lists the suture eyelet coordinates and the distance between the coordinates. Everything the surgeon needs to place the plaque at the planned position is in this document.
The optional 2nd page of the Retinal Diagram document is labeled in degrees CCW (instead of clock hours) in the manner of toric intraocular lens (IOL) axis marking tools such as the Duckworth & Kent Axis Marker model 9-841.
The Isodose document prints the current meridian and coronal dosimetry planes.
The Histogram document prints the Retina Dose Area Histogram (RDAH). The RDAH is a metric for comparing competetive treatment plan options.
The Setup document tabulates eye dimensions, plaque center coordinates and rotational angle, and the current 3D view of the model from the Patient Setup window.
The QA document prints a table containing all of the information needed to manually duplicate Plaque Simulator's simplified (isotropic point source in water) QA check point calculation located at 6 mm on the plaque central axis.
The Print Group button in the toolbar of the Document Preview window prints the group of documents selected by the Document group checkboxes to either paper or to a .pdf file.