Spine SRS

Table of Contents

DVH Display

DVH Display Components


Click on the end of the volume axis and drag to change the Volume scale.

Normal Tissue (NT) graph (see below).

Click on the end of the dose axis and drag to change the Dose scale.

Min. / Mean / Max. doses, CI, GI and relative max. dose are displayed above the DVH.

Hover the mouse over a point to see more data. The constraint is marked on each line. If you hover over the constraint point, a data display including the constraint for this object and the conformity index (for the PTV only) is shown.

The triangle represents the prescription point. If there is a circle around the prescription point, then the goal was not met.

The diamond represents the constraint and objective point. If there is a circle around the diamond, then the constraint and objective were not met.

Interpreting the DVH

The DVH curve Tissue corresponds to the structure of type Outer Contour in the Objects listed under Data.

The DVH curve Normal Tissue corresponds to a virtual structure which is composed of the Tissue minus the PTV.

If no structure is selected from the Objects list under Data, the DVHs for all structures set to visible are displayed. Additionally, the DVH curves Tissue and Normal Tissue are shown even if the structure Outer Contour is not set to visible.

The PTV graph is accompanied by an additional blue line, the Normal Tissue (NT) graph. This curve corresponds to a virtual ring structure around the PTV and is used for the CI calculation. Its percentage volume is normalized to the PTV volume and shown together with the PTV (tumor) volume as NT .

Additional DVH Features

  • The Grid Size: Resolution used for structure discretization during DVH generation
  • The dose algorithm type is displayed below the DVH display
  • Double-click on Volume (above the y-axis) to switch between absolute (cm3) and relative (%) volume.

Art-No. 60919-40EN

Date of publication: 2019-05-22