diff --git a/reg23Topograms/itkDTRrecon/itkImageProcessor.cpp b/reg23Topograms/itkDTRrecon/itkImageProcessor.cpp
index 31740ec..d99b272 100644
--- a/reg23Topograms/itkDTRrecon/itkImageProcessor.cpp
+++ b/reg23Topograms/itkDTRrecon/itkImageProcessor.cpp
@@ -388,6 +388,8 @@ int itkImageProcessor::unload3DVolumeAndMeta(){
     m_TransformMetaInfo = TransformMetaInformation::New();
 
 
+    this->ResetROIRegions();
+
     return 1;
 }
 
@@ -2500,11 +2502,13 @@ void itkImageProcessor::SetRegionFixed2(
 
 void itkImageProcessor::ResetROIRegions(){
 
-    auto region1temp = m_PASourceDupli->GetOutput()->GetBufferedRegion();
-    auto region2temp = m_LATSourceDupli->GetOutput()->GetBufferedRegion();
+//    auto region1temp = m_PASourceDupli->GetOutput()->GetBufferedRegion();
+//    auto region2temp = m_LATSourceDupli->GetOutput()->GetBufferedRegion();
 
-    this->m_R23->SetroiAutoReg1(region1temp);
-    this->m_R23->SetroiAutoReg2(region2temp);
+//    this->m_R23->SetroiAutoReg1(region1temp);
+//    this->m_R23->SetroiAutoReg2(region2temp);
+
+    this->m_R23->setROISizeToZero();
 
 }
 
diff --git a/reg23Topograms/itkDTRrecon/itkReg23.cpp b/reg23Topograms/itkDTRrecon/itkReg23.cpp
index e599807..85c81c1 100644
--- a/reg23Topograms/itkDTRrecon/itkReg23.cpp
+++ b/reg23Topograms/itkDTRrecon/itkReg23.cpp
@@ -46,6 +46,8 @@ itkReg23::itkReg23()
     //    m_UseFullROI = true; // if the full image ROI shall be used
     m_UseDumptoFile = false; //If each (!) optimzer result shall be dumpped into a file.
 
+
+    this->setROISizeToZero();
 }
 
 
@@ -54,6 +56,16 @@ itkReg23::~itkReg23()
 
 }
 
+void itkReg23::setROISizeToZero(){
+
+    ImageType3D::SizeType zeroSize;
+    zeroSize.Fill(0);
+
+    m_roiAutoReg1.SetSize(zeroSize);
+    m_roiAutoReg2.SetSize(zeroSize);
+
+}
+
 void itkReg23::PrintSelf(std::ostream& os, Indent indent) const
 {
     Superclass::PrintSelf(os, indent);
@@ -208,6 +220,18 @@ void itkReg23::InitializeRegistration(
     registration->SetFixedImage2(m_LAT);
     registration->SetMovingImage(m_Volume);
 
+
+    if( this->GetroiAutoReg1().GetNumberOfPixels() == 0 ){
+        auto defaultRegion = m_PA->GetBufferedRegion();
+        this->SetroiAutoReg1(defaultRegion);
+        std::cout<< "Image1 region not defined. Using the whole image buffered region" <<std::endl;
+    }
+    if( this->GetroiAutoReg2().GetNumberOfPixels() == 0 ){
+        auto defaultRegion = m_LAT->GetBufferedRegion();
+        this->SetroiAutoReg2(defaultRegion);
+        std::cout<< "Image2 region not defined. Using the whole image buffered region" <<std::endl;
+    }
+
     registration->SetFixedImageRegion1(m_roiAutoReg1);
     registration->SetFixedImageRegion2(m_roiAutoReg2);
 
diff --git a/reg23Topograms/itkDTRrecon/itkReg23.h b/reg23Topograms/itkDTRrecon/itkReg23.h
index 0154672..f885cc0 100644
--- a/reg23Topograms/itkDTRrecon/itkReg23.h
+++ b/reg23Topograms/itkDTRrecon/itkReg23.h
@@ -108,6 +108,8 @@ public:
 
     /** Auto Reg23 methods END */
 
+    void setROISizeToZero();
+
 protected:
     itkReg23();
     virtual ~itkReg23();