How many more scans are doctors ordering today?

Lots more. The explosion in the number of CT and MRI scans is a major driver of health care spending:

The number of MRI procedures per 1,000 Medicare beneficiaries increased from 0.3 in 1985 to 50 in 1995 and 173 in 2004. Each new MRI unit on the market led to 733 additional MRI procedures, adding $550,000 to Medicare spending annually.

CT scans more than doubled from 235 per 1,000 in 1995 to 547 per 1,000 in 2005. Each new CT unit on the market prompted 2,224 additional CT scans and added $685,000 to the yearly Medicare bill.

Insurers are fighting back by requiring pre-authorizations prior to ordering the scans, but patients need to be educated that not all symptoms need expensive tests.