# Change of tumor location during registration with different templates

**URL:** <https://discourse.itk.org/t/change-of-tumor-location-during-registration-with-different-templates/6726>\
**Category:** Algorithms\
**Tags:** simpleitk, registration\
**Created:** [June 27, 2024, 12:12pm UTC](https://discourse.itk.org/t/change-of-tumor-location-during-registration-with-different-templates/6726 "2024-06-27T12:12:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sunita\_Patel](https://discourse.itk.org/user_avatar/discourse.itk.org/sunita_patel/32/3347_2.png) [@Sunita\_Patel](https://discourse.itk.org/u/Sunita_Patel)\
**Post date:** [June 27, 2024, 12:12pm UTC](https://discourse.itk.org/t/change-of-tumor-location-during-registration-with-different-templates/6726/1 "2024-06-27T12:12:42Z")

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Dear ITK forum Members,

All our registrations are performed using Simple ITK.  
T1 weighted image is registered with SRI24 atlas (240,240,155) as a template (1st image) and with MNI152 (197,233,189) atlas (2nd image). 2nd image is re-registered with SRI24 again (3rd image).

After registration, we observed that the tumor location is changing in SRI (1st image) and MNI (2nd image) registration for the same patient T1-weighted image. Could you please guide us why the tumor location is changing in SRI and MNI registered images?

In all these examples voxel volume is fixed that is 1 mm^3. However, non-zero voxel volumes are different for different template references for the same patient T1-weighted image as shown below.

 ![T1W_SRI_MNI_SRI_registered](https://discourse.itk.org/uploads/default/original/2X/2/23b0b6ac4aa35c467b02c1bdd024bacceea0d874.jpeg)

Non-zero brain volume of SRI registered T1 image (1st Image): 1512233  
Non-zero brain volume of MNI registered T1 image (2nd Image): 793562  
Non-zero brain volume of MNI to SRI registered T1 image (3rd Image): 1710923

The main concern is that why the tumor location is changing with different reference template? Why there is a change in volume between 1st and 3rd image?

Your help will be highly appreciated.

Thank you so much.

Best regards,  
Sunita

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**Author:** ![Sunita\_Patel](https://discourse.itk.org/user_avatar/discourse.itk.org/sunita_patel/32/3347_2.png) [@Sunita\_Patel](https://discourse.itk.org/u/Sunita_Patel)\
**Post date:** [June 28, 2024, 6:40am UTC](https://discourse.itk.org/t/change-of-tumor-location-during-registration-with-different-templates/6726/2 "2024-06-28T06:40:52Z")

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Dear Ziv,

You have expertise in this area. I am sure you have a solution for this.  
Could you please guide.

Thank you so much.  
Sunita