GetVolumeatDose returns NaN

Jan 19, 2016 at 2:37 PM
I have written a script which uses the GetVolumeatDose method, the script has run without problems for > 20 patients however last week I came across a patient in which the GetVolumeatDose Method returned "NaN".

I have checked that all the inputs are correct for this patient but cannot determine why the Method returns NaN.

The exact call is:
dose50vol = plan.GetVolumeAtDose(body, new DoseValue(plan.TotalPrescribedDose.Dose * 0.5, DoseValue.DoseUnit.cGy), VolumePresentation.AbsoluteCm3);

"body" is the body contour and I have checked that it returns the correct volume.
The second parameter return 2500 (as expected - the plan is 5000cGy in 5Fx)

I am using version 11. Any help would be appreciated.
Jan 29, 2016 at 12:40 PM
There might not be enough dose coverage, I believe ESAPI returns NaN in that case. Since GetVolumeAtDose is just a convenience method, you can get the actual DVH data and see what it looks like.