Dose-volume histogram

In modern radiation therapy, 3D dose distributions are typically created in a computerized treatment planning system (TPS) based on a 3D reconstruction of a CT scan.

[4] The size is often a matter of tradeoff between accuracy and computational or memory cost (if we store the DVH in a database).

[5] This volume is determined by the total number of voxels characterized by a specified range of dosage for the organ considered.

[5] The column height of the second bin (e.g., (1, 2] Gy) represents the volume of structure receiving greater than or equal to that dose, etc.

With very fine (small) bin sizes, the cumulative DVH takes on the appearance of a smooth line graph.

[9] Also, DVHs from initial radiotherapy plans represent the doses to structures at the start of radiation treatment.