There's a shortage of certain barium medical products, but is seems nothing more than economics or supply chain issues, seemingly mostly because of the near monopoly of Bracco Diagnostics.
Content from external source:
September 26, 2012
Re: Barium Products Backorders
As you may know, we have experienced numerous backorders with our barium portfolio in recent months. These backorders are due to delays from one of our primary barium suppliers, which they are working to address. To date, we have been able to provide other products to meet the needs of most clinicians performing procedures associated with backordered products. However, the demand for these other products has been overwhelming, and we are now also backordered with respect to these products.
With the continued efforts of our barium supplier, we are attempting to make all of the key backordered products available as soon as possible. However, at this time, there are procedures for which we are unable to provide products. Below is a list of the products that are currently backordered or low in supply and the available products, if any.
The conspiracy minded part of me would suspect this is Bracco trying to raise prices.