If the PA is doing the independent visualization of the x-ray and your provider is looking at that report and signing that he/she agrees with the report...the provider may not bill for reading of the x-ray. He/she did not actually visualize/read the x-ray. In other words did not perform the service of visualizing the xray.
I'm sure your provider does not want to bill for a service he or she did not provide....doing so could be considered fraud.
If your provider wants to bill for the reading of the x-ray, he or she needs to actually perform the full service/full reading.