The IP.com Journal (v8n9B)
Juergen Carstens - Contact
firstname.lastname@example.org; phone +49-89-636-82995
SIEMENS AG 2008
English (United States)
5 pages / 67.8 KB
Better Approach for Presenting Dose Volume Histogram (DVH)
Idea: Manivannan Sundarapandian, IN-Bangalore
In the field of radiation oncology, DVHs (Dose Volume Histograms) are frequently utilized as a component of treatment plan evaluation. The purpose of the DVH is to assist the physician in determining the ideal plan for a given patient by summarizing the 3-D dose distribution data for the organs in the treatment volume and displaying it in a graphical format. DVHs can be visualized in either of two ways: differential DVHs or cumulative DVHs. A differential DVH is a graph f(V, D) wherein a point (V,D) denotes the percentage volume of an organ V receiving a dose of D%. A cumulative DVH gives the plot F(V, D) of percentage volume of an organ V receiving a dose of D% or higher. For the DVH to be calculated, the volumes of interest are outlined on each contiguous and parallel slice of a given patient's CT (Computer Tomography) scan. The anatomy is then divided into a volume grid. By defining the grid's matrix size, the resolution is defined. This, in turn, establishes the volume elements (voxels) of the identified anatomy.
In TPS (Treatment Planning Software) systems, the dose and volume percentages are usually calculated with respect to the prescribed dose and the contoured organ volume respectively. However, the DVHs do not provide information on the location of the dose levels within the structure. This inherent loss of spatial data with the formation of a DVH can be misleading when evaluating a dose distribution.
It is proposed to provide a synchronized view of both the DVH and the dose visualization in the image volume. This view, referred as DVH-Synch view in the following, displays the information about the DVH, the dose, structure sets and images. The structure sets are representations of organs such as tumors, organs at risk, etc. The images may be CT slices, for example. The DVH-Synch view contains two sub views:
1) DVH Sub-view, which displays the DVH either in differential or cumulative form. For synchronizing the DVH and the 2D image an interactive element is used.
2) Image Sub-view, which displays 2D images including contours of selected structures (organs) and the dose footprint. The images can be displayed along three orientations: axial, coronal and sagittal. Multiple images can be navigated using sequential image navigator. The voxels of the organ where the dose has been received may also be highlighted in a selected DVH mode.
The visualizations are synchronized by means of three controls:
1) Point Control: The user can move the Point Control along the DVH and place it on an arbitrary point (Vp,Dp). Upon this action, the Image Sub-view displays the image slices of the organ (or its portion) that receive Dp dose or higher. The voxels receiving Dp dose or higher are highlighted on the images. The s...