# how to get the mouse coordinate on dicom

**URL:** https://discourse.vtk.org/t/how-to-get-the-mouse-coordinate-on-dicom/8187
**Category:** Support
**Created:** [March 31, 2022, 2:30pm UTC](https://discourse.vtk.org/t/how-to-get-the-mouse-coordinate-on-dicom/8187 "2022-03-31T14:30:03Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![longjiang321](https://discourse.vtk.org/user_avatar/discourse.vtk.org/longjiang321/32/8727_2.png) [@longjiang321](https://discourse.vtk.org/u/longjiang321)
#### Post date: [March 31, 2022, 2:30pm UTC](https://discourse.vtk.org/t/how-to-get-the-mouse-coordinate-on-dicom/8187/1 "2022-03-31T14:30:03Z")

</div>

hi friends:  
I am trying to run the offically provide demo [https://kitware.github.io/vtk-examples/site/Cxx/Images/PickPixel2/](https://kitware.github.io/vtk-examples/site/Cxx/Images/PickPixel2/), for JPEG image(use vtkJPEGReader to load it), the mouse coordinate and pixel value get successfully, it as below:

 ![image](https://discourse.vtk.org/uploads/default/original/2X/5/563164758b2e6a8a63d3ed8521801d0c198b8839.jpeg)

but for dicom (use vtkDICOMReader to load it), the mouse coordinate and ct number get failed.

 ![image](https://discourse.vtk.org/uploads/default/original/2X/1/1e4d8f173a3ce55c5567401065c8860db5aa2da3.png)

as my debug, vtkAssemblyPath\* path = this-\>Picker-\>GetPath(); the path is always null

anybody had encounter this issue ? or other better solution to get the mouse coordinate ?

many thanks in advance!!!