dose mapping with series of png image containing ct and dose integreted

How to do dose mapping with a series of png images containing ct and dose integrated through customized slicer 3d?

What do you mean by dose mapping?

How did you end up with having png images that contain CT and dose? Normally you would save images in DICOM or standard 3D image formats (nrrd, mha, …).

I got screenshots of images having both CT and dose in png. Now can I convert into Dicom back?
Or can i convert it by exported nrrd file back to dicom?
One more question - how can i export dicom ct slices + corresponding dicom dose file into file integrated dicom so that i can export into nrrd file format?