diff --git a/src/thermophysicalModels/radiationModels/derivedFvPatchFields/greyDiffusiveRadiation/greyDiffusiveRadiationMixedFvPatchScalarField.C b/src/thermophysicalModels/radiationModels/derivedFvPatchFields/greyDiffusiveRadiation/greyDiffusiveRadiationMixedFvPatchScalarField.C
index b4d433d425e1036d70b109ed5ca70d4e9b71e787..7237f30307fc3baa38d0c9fba66521e9a4a084c1 100644
--- a/src/thermophysicalModels/radiationModels/derivedFvPatchFields/greyDiffusiveRadiation/greyDiffusiveRadiationMixedFvPatchScalarField.C
+++ b/src/thermophysicalModels/radiationModels/derivedFvPatchFields/greyDiffusiveRadiation/greyDiffusiveRadiationMixedFvPatchScalarField.C
@@ -197,7 +197,7 @@ updateCoeffs()
 
     const vector& myRayId = dom.IRay(rayId).d();
 
-    const scalarField& Ir = dom.Qin();
+    const scalarField& Ir = dom.Qin().boundaryField()[patchI];
 
     forAll(Iw, faceI)
     {