# How to calculate dose with parallel world(geometries)

hi, everyone
I recently want to calculate the dose use alternative geometries.（concentric spheres overlaped）
I get deposited energy with following code:

Edep = step->GetTotalEnergyDeposit();
G4String PhysicalVolumename = step->GetPreStepPoint()->GetPhysicalVolume()->GetName();
if (PhysicalVolumename == “wholePhantom”)
{
G4String MetarialName = step->GetPreStepPoint()->GetMaterial()->GetName();

``````	int MetarialID= splitnum(MetarialName);

fEventAction->AddOrganDose(MetarialID, Edep*Weight);

}
``````

but I compared the calculation results using the same geometries but not constructed with alternative geometries, I find these different with each other.

could you give me some advice？Thank you！