Diffusion and Utilisation of MRI in Thailand. MRI is one of the big ticket technology that is expensive in both its procurement cost and its maintenance. This study assesses the efficiency and equity of MRI services by looking at the patterns of diffusion and utilisation in Thailand. The study shows that, since the first introduction of MRI machine in the private facility in 1988, the number of MRI has been gradually increasing both in public and private health sectors. In 1998, Thai people have the choice of getting MRI services from 25 MRI machines in operation; 9 of them are in public hospitals and the rest are in private facilities (10 in private hospitals and 6 in private freestanding diagnostic centers). Most of the machines are located in Bangkok area (17 places). All MRI in the public hospitals have the magnetic power of 1.5 Teslas. The private machines however possess various level of magnetic strength ranging between 0.2 to 2 Teslas. Average operating time per week in the public hospitals is much lower than that in private facilities. Average number of cases operated per machine per year in 1997 is 1,233. There are 6 MRI units with less than 500 patients being examined that year. From the interview with 23 facilities' owners or hospital or center administrators we find out that the nature of technology, planning and logistics are two main stimulating factors for the MRI machine procurement while the budget for investment is the most impeding factor. From the costing studies in 8 sampled MRI units, the results show that capital depreciation cost is the major portion, over half, of total cost of MRI operation. Number of cases operated is the key factor determining their financial results. Majorities of MRI units are operating on lost while only 2 out of 8 sites have nearly 100% cost recovery. The rest are striving with the cost recovery figures between only 12 to 41 percent. The break-even points for MRI operation are calculated to be at around 1,300 cases per year for private facilities and more than 2,500 cases per year for public facilities. The utilization study reveals that there is inequitable MRI access as shown in different rate of its usage among patients from different payment scheme. We furthermore detect that many MRI units under private settings offer financial incentives to the physicians who refer cases to their sites by routing back a certain proportion of service charge acquired from the patients. This controversial way of promotion, "Kick back”, may lead to inappropriate utilisation and should be seriously addressed by regulators, professional organization, and consumer protection agencies. The research team has proposed several recommendations to counteract the problems of inefficiency, inequity and questionable quality of MRI services. We support the upcoming draft of the new Medical Device Act that will embody the regulation on number and distribution of certain medical devices using evidence based on pidemiology, demographic pattern and the distribution of existing facilities. Monitoring and assessing bodies must be empowered with skill and knowledge. Better use of the existing MRI machines will definitely be highly appreciated by all. Strengthening of the service network and referral system is one possible way. Continuing medical education for doctors, radiologists and other staffs together with more public education on the indication of use, benefit and cost of MRI technology will help. Likewise, the fundamental problems resulting from inefficient and unfair health financing and delivery system should not be overlooked.