# (no subject)

**URL:** <https://castor-project.discourse.group/t/no-subject/164>\
**Category:** General Discussions\
**Created:** [August 7, 2020, 3:41pm UTC](https://castor-project.discourse.group/t/no-subject/164 "2020-08-07T15:41:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Pedro\_Henrique\_Durao](https://avatars.discourse-cdn.com/v4/letter/p/50afbb/32.png) [@Pedro\_Henrique\_Durao](https://castor-project.discourse.group/u/Pedro_Henrique_Durao)\
**Post date:** [August 7, 2020, 3:41pm UTC](https://castor-project.discourse.group/t/no-subject/164/1 "2020-08-07T15:41:14Z")

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Dear CASToR user´s,  
I am working on a simulated PET scanner in GATE. I set up a point source in a FOV center, and set a static PET with 10 monolithic detectors. When I perform the reconstruction, the image result appears with a star artifact. How can I solve this problem? The images are attached.

Thank you for your help in advance.

Regards,  
Pedro.

 ![pointsourcewithartifact.png](https://global.discourse-cdn.com/free1/uploads/castor_project/original/1X/cd09c1bd9df234d0c94427f1dfccc34a2155eb4e.png)

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**Author:** ![Pedro\_Henrique\_Durao](https://avatars.discourse-cdn.com/v4/letter/p/50afbb/32.png) [@Pedro\_Henrique\_Durao](https://castor-project.discourse.group/u/Pedro_Henrique_Durao)\
**Post date:** [August 7, 2020, 7:12pm UTC](https://castor-project.discourse.group/t/no-subject/164/2 "2020-08-07T19:12:32Z")

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Dear CASToR user´s,  
I am working on a simulated PET scanner in GATE. I set up a point source in a FOV center, and set a static PET with 10 monolithic detectors. When I perform the reconstruction, the image result appears with a star artifact. How can I solve this problem? The images are attached.

Thank you for your help in advance.

Regards,  
Pedro.

 ![pointsourcewithartifact.png](https://global.discourse-cdn.com/free1/uploads/castor_project/original/1X/cd09c1bd9df234d0c94427f1dfccc34a2155eb4e.png)

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**Author:** ![Virtuall](https://avatars.discourse-cdn.com/v4/letter/v/ecd19e/32.png) [@Virtuall](https://castor-project.discourse.group/u/Virtuall)\
**Post date:** [August 11, 2020, 3:11pm UTC](https://castor-project.discourse.group/t/no-subject/164/3 "2020-08-11T15:11:35Z")

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Hi Pedro,

Could you share some related part of your GATE macro of this simulation? I don’t think the issue is with castor, so more details will make us easier to help you.

Best,

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**Author:** ![FILIPOVIC\_PIERUCCI\_M](https://avatars.discourse-cdn.com/v4/letter/f/8491ac/32.png) [@FILIPOVIC\_PIERUCCI\_M](https://castor-project.discourse.group/u/FILIPOVIC_PIERUCCI_M)\
**Post date:** [August 17, 2020, 8:24am UTC](https://castor-project.discourse.group/t/no-subject/164/4 "2020-08-17T08:24:56Z")

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Hi,

Have you thought about the spatial resolution capacities of a PET scanner with only 10 detectors? It might be too coarse to resolve a point source, depending on the size of the detectors etc.

Best

Marina Filipovic