Independent DVH calculation with OCTAVIUS® 4D

What are DVHs and why use them?


Dose-volume histograms (DVHs) are graphical plots which summarize dose distributions throughout a particular volume or structure of interest. They have become a useful and common tool for medical physicists and physicians to

  • assess if the tumor is adequately covered while the healthy surrounding tissue gets only a minimal dose.
  • evaluate the suitability of a particular treatment plan.
  • optimize treatment plans based on additional dose data.
  • compare different treatment plans to determine the best treatment plan for the patient.

 

What is DVH 4D for VeriSoft?


DVH 4D is an optional DVH analysis software tool for OCTAVIUS 4D and fully integrated with VeriSoft. It calculates DVHs based on the patient's anatomy using OCTAVIUS 4D measurement data and patient contours and densities derived from the patient's CT. The DVHs calculated by DVH 4D are then compared with the DVHs calculated by the TPS. Cumulative DVHs can be calculated and graphically displayed for all structures imported from RTStruct. DVH calculation with DVH 4D is very fast, taking less than five minutes. The DVH plot can be saved for documentation or printout.
As an independent tool, DVH 4D requires no TPS dose data for its calculation, but uses a unique algorithm based on PDD curves computed in the patient CT. To determine the PDD curves within the patient, the water-equivalent depth of each voxel is calculated for each gantry angle and an SSD correction factor is applied.


DVH 4D - truly independent DVH calculation  

Unlike other QA devices, DVH 4D performs its calculations truly independently from the TPS as it requires no TPS dose data for DVH calculation.   To calculate DVHs, DVH 4D converts PDD curves provided by the user to tissue phantom ratios (TPRs). Using the patient's CT, the water-equivalent depth of each voxel is calculated. Combining this depth information with the TPR and the known distance to the focus, the dose in each voxel can be calculated from the dose data measured in the array plane. Doing this for each detector of the array and for all gantry angles yields the dose in the patient's anatomy from which DVHs are extracted.


Why use DVH 4D?


DVH 4D for VeriSoft

  • gives you an additional plan evaluation tool to help you better assess target coverage.
  • provides a DVH analysis truly independent of the treatment planning system (TPS) as it requires no dose data from the TPS. Its DVH calculations are based on measured data obtained with OCTAVIUS 4D and patient CT data.
  • performs its calculations in less than a few minutes using a sophisticated calculation algorithm and advanced software technology.