ASTER 1A/1B datasets have scale factors that can be applied to the dataset to convert them to radiance. When you open these files in ENVI using File->Open As->EOS ASTER (or MODIS), these scale factors are automatically applied to the dataset and when you bring up the Cursor location/value tool, the pixel values should already be in floating point radiance. So yes, it is possible to write a program in IDL that will extract the scale factors from the ASTER HDF tags and automatically apply them to the data. However, if you have ENVI, all you should need to do is open the dataset as ASTER and the scale factors are applied automatically.

HI! And is possible to write this program for working with an input of 50 ASTER 1B datasets?

You would just need to open the files in ENVI (5.x) using the ENVIRaster method and the eos_aster keyword. Then save the result to an ENVI file using the Export method. You could do this in a FOR loop.