Planar Dosimetry Window

The Planar Dosimetry window displays isodose maps, plaque(s), points of interest, dose profile lines and anatomy on planar cross sections of the eye. The default display is a single pane illustrating a meridian plane bisecting the eye through the center of the active plaque. The meridian planne can be rotated about the AP axis of the eye. A coronal plane that, by default, bisects the eye at the equator may be also be displayed instead of, or in addition to the meridian plane. Controls to rotate the meridian and translate the coronal plane are provided. The planar cross sections may optionally be superimposed over calibrated CT or MR images.

The status line just below the window title bar lists the currently active dose matrix set, surface, matrix size and surface orientation or offset from the equator.

Points of interest (POI) and a user defined prescription (Rx) point may be digitized by enabling the appropriate cursor mode and clicking on the diagram. A ruler tool allows measurement between points. In the example on the right, a chord distance of 4.18 mm between the limbus and the projection onto the outer scleral surface of a suture eyelet is illustrated.

Additional control over 2D isodose plotting is provided in the Plot menu.

Toolbar controls

The toolbar buttons near the top of the window select the dose matrix set, cursor function, and window layout.

Plaque 1..4 - Selects the plaque (and its associated dose matrices) that is currently "active".

Crosshair

Sets the mouse cursor function to display information about the point clicked.

Point of Interest

Sets the mouse cursor function for digitizing points of interest (POI).

Rx Point

Sets the mouse cursor function for digitizing a Rx point.

Profile

Sets the mouse cursor function for manipulating dose profile lines.

Lock

Locks all 2D planes for all plaques at their current locations and disables all controls that vary plane location across all windows and menus.

Auto

Enabling the automatic (live) Rx updating control in the toolbar (or holding down the option key while dragging the Rx point) will automatically rescale isodose lines and seed strengths in order to maintain the current Rx conditions while the Rx point (or a Rx POI) marker is dragged on the plane. The dose histogram is also automatically updated. The current 2D plane must intersect the Rx point (or POI) in order for the point markers to be visible. If the current Rx mode is a plaque or tumor axis distance, the dragged Rx point will be constrained to the appropriate axis during the drag and might disappear from the window because it no longer intersects the current plane. For all other Rx modes, the Rx will be automatically changed to absolute coordinates mode at the beginning of the drag.

Profiles

Displays the dose profiles toolbar.

Single pane

Displays only the currently active dosimetry set. To facilitate rapid dosimetric comparison of prospective plaque designs, Plaque Simulator supports 4 plaques and 4 dosimetry sets per patient. By default, each dosimetry set is associated with a corresponding plaque. Set 1 is associated with plaque 1, set 2 with plaque 2, and so on. Only one plaque (and its dosimetry set) at a time are normally considered to be "active". Changing either the active plaque or the active dosimetry set autmatically changes both the plaque and its associated dosimetry set. (This behavior can be disabled in case you wish to apply all four sets to the same plaque).

Dual pane

Displays side-by-side meridian and coronal dosimetry for the active dosimetry set.

Dual pane

Displays stacked meridian and coronal dosimetry for the active dosimetry set.

Four pane

Displays meridian or coronal all four dosimetry sets.

Calculate Matrix - When in single pane mode, recalculates the 2D dose matrix for the current plane. When in dual or quad pane mode, calculates all 2D matrices and dose histograms. Same as clicking Calculate 2D Matrices in either the Dosimetry menu or Retinal Diagram window toolbar.

Click the Profiles button to display the dose profiles toolbar. The buttons in the profiles toolbar activate the display of dose profile lines. Dose profile lines and their endpoints can be dragged in a manner analogous to points of interest using the profile (PROF) mouse cursor function. Note: Profiles 15 and 16 are reserved for autoradiographs.

Planar group

Meridian - Makes the meridian plane the active context when in single pane layout mode, the popup menu selects dose matrix size and some standard plane locations.
- 90 X 90 - Low resolution (fastest).
- 120 X 120 - Medium resolution.
- 180 X 180 - Standard resolution.
- 270 X 270 - Better resolution.
- 360 X 360 - High resolution.
- 540 X 540 - Higher resolution.
- 720 X 720 - Maximum resolution (slowest).

Coronal - Makes the coronal plane the active context when in single pane layout mode, the popup menu selects dose matrix size and some standard plane locations.
- 90 X 90 - Low resolution (fastest).
- 120 X 120 - Medium resolution.
- 180 X 180 - Standard resolution.
- 270 X 270 - Better resolution.
- 360 X 360 - High resolution.
- 540 X 540 - Higher resolution.
- 720 X 720 - Maximum resolution (slowest).

Nerve - Makes the nerve-coronal plane the active context when in single pane layout mode, the popup menu selects dose matrix size and plane x-offset from the posterior pole.
- 90 X 90 - Low resolution (fastest).
- 120 X 120 - Medium resolution.
- 180 X 180 - Standard resolution.
- 270 X 270 - Better resolution.
- 360 X 360 - High resolution.
- 540 X 540 - Higher resolution.
- 720 X 720 - Maximum resolution (slowest).
The nerve-coronal plane location is expressed as an x-offset in mm from the geometric posterior pole. The geometric posterior pole is modeled as being at the inner scleral surface near the fovea. The default scleral thickness is 1.0 mm and the default x-axis offset of the nerve coronal plane is -0.5 mm, centering the nerve-coronal plane in the sclera just posterior to the pole and intersecting the posterior sclera and about 2/3 of the optic nerve.

This is an example of a multiplanar CT reconstruction of the nerve-coronal plane from a 3D axial series with slice thickness of about 0.6 mm. The crosshairs are centered on Plaque simulator's x-axis which passes through the poles. Visible are the rectus muscles and the nerve where it connects to the sclera.

Misc. - Makes the miscellaneous plane the active context when in single pane layout mode, the popup menu selects dose matrix size .
- 90 X 90 - Low resolution (fastest).
- 120 X 120 - Medium resolution.
- 180 X 180 - Standard resolution.
- 270 X 270 - Better resolution.
- 360 X 360 - High resolution.
- 540 X 540 - Higher resolution.
- 720 X 720 - Maximum resolution (slowest).

Autoradiograph - Makes the autoradiograph plane the active context when in single pane layout mode, the popup menu selects dose matrix size.
- 90 X 90 - Low resolution (fastest).
- 120 X 120 - Medium resolution.
- 180 X 180 - Standard resolution.
- 270 X 270 - Better resolution.
- 360 X 360 - High resolution.
- 540 X 540 - Higher resolution.
- 720 X 720 - Maximum resolution (slowest).

Rotate & Translate group

Meridian CCW - Rotates the meridian plane CCW.
Axial Bisector - Rotates the meridian plane to become the axial bisector. The axial bisecting plane is also known as the 9 o'clock meridian and/or the 180° toric angle meridian in some contexts.
Meridian CW - Rotates the meridian plane CW.

Coronal Posterior - Translates the coronal plane towards the fovea.
Equator - Translates the coronal plane to the equator of the eye.
Coronal Anterior - Translates the coronal plane towards the cornea.

Tools group

Ruler - Enables display of the distance measuring ruler tool. Use the contextual menu to customize ruler properties.
- Ruler Properties... - Opens the ruler properties sheet where you can customize ruler properties and enable multiple rulers. All rulers share a common calibration.
- Rx Point Distance - A special ruler that plots and labels a vector between a location of interest and the Rx point when that vector lies entirely in the plane.
- Rx Point Properties - Opens a sheet in which you can customize the Rx Point Distance tool.

Eyelet - Cycles the meridian plane to pass through the next suture eyelet, or move directly to a selected eyelet via the contextual menu of this button.
- A1 etc... - Rotate the meridian plane to pass through the selected eyelet. This menu's appearance varies with the number of eyelets attached to the current plaque.

Flip 180 - Flips the meridian plane 180° to match MPR images.

Optic Disc group

Elevation - The angle of elevation of the center of the optic disc from the geometric axial bisecting plane. Plaque Simulator models the geometric axial bisecting plane as being equivalent to the 9 o'clock (and/or the 180° toric angle) meridian plane. By default, Plaque Simulator models the disc elevation as 0.0°, ie the disc is centered on the axial bisecting plane. Disc elevation is usually close to zero but we have observed instances of up to ± 10°.
Azimuth - The azimuthal angle between Plaque Simulator's geometric x-axis which passes through the anterior and posterior poles and the geometric center of the optic disc. By default, Plaque Simulator models the disc azimuth as being 21.9° which is about 4.18 mm chord distance for a 24 mm equatorial diameter eye. Azimuth angles tend to range between 18° and 26°.
Sheath Diameter - The optic disc, as it appears in fundus photography of the retinal surface of the eye, is about 2 mm diameter. The optic nerve, as part of the central nervous system, is surrounded by a dural sheath. This slider control adjusts the optic nerve sheath diameter (ONSD) where it connects to the eye. The default ONSD is modeled in Plaque Simulator as being 5.0 mm, with diameters ranging from 4.5 to about 6 mm being commonly observed. ONSD greater than 5.8 mm is reportedly associated with raised intracranial pressure (ICP). The ONSD is of interest for treatment planning because it physically limits how closely a plaque (being located as it is on the outside of the eye) can position its radionuclide sources (aka seeds) to the perimeter of the optic disc when treating peripapillary tumors.

The pane on the left above illustrates the optic disc & nerve azimuth angle on the axial bisecting (aka 9 o'clock) meridian plane. The pane on the right illustrates the optic nerve & disc elevation with respect to the axial bisecting plane in the coronal "nerve plane" located 0.5 mm posterior to the posterior pole as illustrated in the meridian plane pane.

Isodose group

Matrix - Displays the dose matrix grid.
Lines - Enables isodose lines, popup menu changes labeling properties.
Tint - Enables isodose areal tinting, the popup menu adjusts tint opacity.
Tint Contextual Slider - Adjusts isodose tinting opacity.

Isodose labels spacing slider (S) - Interactively adjusts the initial default location of isodose labels before any shifting required to prevent overlap.
Isodose labels clustering slider (C) - Isodose labels on the plane gravitate towards the center of the eye but are not allowed to overlap. This slider interactively adjusts the allowed proximity between isodose labels.
Isodose labels font size slider (F) - Interactively adjusts the isodose label font size.

Overlay group

Calibrated image file overlays:

These controls are enabled if a corresponding image file has been loaded and calibrated or has been statically captured from the MPR window. The controls are disabled if no calibrated image exists.

Axial - Overlays the plot on a calibrated axial image.
Equator - Overlays the plot on a calibrated equatorial image.
Sagittal - Overlays the plot on a calibrated sagittal image.
T-Cor. - Overlays the plot on a calibrated tumor-coronal image.
T-Mer. - Overlays the plot on a calibrated tumor-meridian image.
Nerve - Overlays the plot on a calibrated nerve-coronal image.
US1 - Overlays the plot on calibrated ultrasound image #1.
US2 - Overlays the plot on calibrated ultrasound image #2.
Misc. 1 - Overlays the plot on calibrated miscellaneous image #1.
Misc. 2 - Overlays the plot on calibrated miscellaneous image #2.
Misc. 3 - Overlays the plot on calibrated miscellaneous image #3.
Misc. 4 - Overlays the plot on calibrated miscellaneous image #4.
Misc. 5 - Overlays the plot on calibrated miscellaneous image #5.
Misc. 6 - Overlays the plot on calibrated miscellaneous image #6.

Other overlay controls:

None - Draws the plot over a plain white background.
Flip - Vertically flips the selected image.
Clr All - Clears all image overlays.
Use MPR - Reconstruct overlays from the MPR series. Enabling MPR reconstructions disables overlays of image files and captures.