than 50 percent of all health expenditures. The bottom 70 percent of users account for only 10 percent of health care costs. The aging population stimulates the demand for health care, and the elderly make up most of the top users. High technology is another reason health care costs have risen dramatically. For example, a CT scanner costs around $100,000, an MRI scanner can cost more than $2 million, and a PET scanner costs around $4 million. Fees for using These machines can cost between $300 and $2,000. Finally, Medicare, Medicaid, and private insurance companies are third parties. When they pay for medical costs, the demand for services increases. Medicare and Medicaid are the main providers of hospital and other benefits to 35 million Americans, most of whom are over the age of 65. Medicaid, a joint state and federal program, provides long-term health care (nursing homes). There is an inverse relationship between the price and quantity demanded of medical services.