You can see precise dose amounts per volume by hovering over the DVH with the mouse.
Click on the end of the volume axis and drag to change the Volume scale.
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 ①.
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 is shown (only for PTVs in the reference plan).
The triangle or diamond (depending on the treatment planning software) represents the prescription point. If there is a circle around the prescription point, then the goal was not met.
The diamond represents the desired/maximum dose constraint. If there is a circle around the diamond, then the desired/maximum dose constraint was met.
|Dose algorithm used to calculate the treatment plan. This can be either Pencil Beam or Monte Carlo.|
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 patient geometry (tissue model and objects) and prescriptions are based on the reference plan, even if other dose plans are loaded for summation or comparison. Therefore, the DVH shows the prescription points for the reference plan only. Conformity indices can only be computed for the PTVs in the reference plan.
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.