Most large practices perform the blood work, the x-rays, have partnerships with the labs that do the CAT scans. Don't tell me they make no money off the tests.
A negotiated price to save their patients some money is not making any money for the Doctor. If you believe the practice is getting a kickback then I suggest you call CMS. You can probably get a cash payment for exposing the backend payments under the medicare whistleblower program.
Are there doctors and hospitals that are trying to work a scam. There probably are, but medicare has computer programs that run through all the payments out to these doctors because they are practicing beyond the average of the rest of the doctors in the program. So in our computer age the kinds of cheating you are talking about is difficult to do for long.
But many are just responding to perceived litigation risks. What's a $1200 CT scan if it may save a doctor a lawsuit? I don't think the malpractice lawyer's retainer is that low. Not to mention that a doctor has to list every malpractice case ever brought when he goes looking for a job which may mean if you have too many litigations you are going to be limited in what jobs you can obtain. Hospitals would rather take an unproven fresh out newbie with no litigation to an experienced Doctor with 4-5 settled cases with no admission of malpractice.
CMS also publishes a list of the groups that receive the most claims from medicare. You can certainly see if your Doctors group is one of the high rollers in the medicare program.
If you have private insurance many times you will be denied access to further labs and imaging. A nurse or doctor working for the insurance company will review the medical chart and deny the extra labs or imaging. The great thing there is if you don't fight them and you had an undiscovered cancer, you have no legal recourse against your insurance company or the administrative doctor/nurse that denied your tests.