A Return on Investment (ROI) or referred to as a "Gain" is the big picture of how well a hospital organization is performing. In order to measure this performance. If you want to have a successful department (business) then you need to measure the amount of your own time invested or the amount of actual money your organization spent on the new equipment purchase. A ROI is represented by a percentage of return and any positive number represents organizational growth or a good purchase expected to make money over x number of years.
The BMETWiki hospital decided with the help of staff (clinical engineers, nurses, facility managers, medical supply, etc) to invest $100, 000 in the purchase of a new MRI Scanner. The new scanner will be used to assess cancer cell research for the surrounding community. From that new scanner, they are projecting to see 50 new patients per year. Since the purchase was successful and the device now installed, they were definitely able to see 50 patients in year one. This resulted into a net profit of a whopping $500,000 (a return on your new purchase investment). Lastly, lets pretend that the cost to send those 50 patients outside our network or to some other specialty for MRI scanning costs the hospital organization $700,000 over one year. 
$ ROI percent or Gain = (Return On Investment - Initial Investment) / Investment * (100) $
To calculate using these steps...
Step 1: $ 4 = (500,000 - 100,000) / 100,000 $
Step 2: $ 400 percent = 4 * 100 $
Answer 400 percent return on investment for your new purchase (the first year).
So, any hospital administrator can see that without this new investment the hospital loses $300,000 ($700,000 - 500,000) per year. The bottom line is that we want more patients each year seen at our hospital because patients make the hospital money. As Biomeds how can we improve technology, provide a safe environment that patients want for their money by preventing mishaps (no-one wants to go to the hospital to get hurt!), and save nurses and providers time so they can provide higher quality of patient care so patients know they get what they paid for which is the best medical care at the best price.
- ↑ Heesen,Mike., "How to Calculate ROI - Calculating Return On Investment - Measuring Your Business Performance". Retrieved 2011. http://ezinearticles.com/?How-to-Calculate-ROI---Calculating-Return-On-Investment---Measuring-Your-Business-Performance&id=5345563