Radiation therapy availability around the world

As a medical physicist, you often have to explain to people what it is exactly that you do. A couple of years ago I met a diplomat from Togo who asked me what I was studying (at the time). My attempt to explain medical physics to him was made all the more difficult, when it became clear that radiation therapy was not something that was available in his country and he had no familiarity with it.

That discussion stuck in my mind and I began to wonder, what exactly is the availability of radiation therapy around the world. Fortunately, the International Atomic Energy Agency is much more concerned about that question than I am and has been keeping stats on that very topic since 1959 via their DIRAC project. Besides providing statistics on the number of clinics and machines in each country, a project named after a prominent physicist also lists stats on the number of medical physicists in each country.

IAEA statistics on radiation therapy machines per capital in 2010.

The above map color codes each country as a function of radiation therapy machines (linacs, teletherapy, or HDR) per capita as of 2010. A more up-to-date, interactive version is found here. The DIRAC site also provides the raw data and even information on individual clinics in each country.

While there are certainly non-negligible error bars on their data, the numbers are revealing, though largely what you'd expect. The highest GDP per capita (or likely highest health spending per capita) countries show up in green on the above map (5 or more machines per million) and the poorest countries show up in dark orange or red ( < 1 machine per million). Togo is red because it has zero machines.

I think the main implications on the medical physics end is with regards to education and dissemination of current knowledge to countries with few physicists. The US, population approximately 3.1x10^8, is listed as having 1728 therapy physicists (probably a low estimate) versus India, population approximately 1.2x10^9, listed as having 144 therapy physicists. Clearly the man-years of experience are highly concentrated in the green countries. I'll claim that it's our duty in the green countries to help educate our colleagues in the countries with less local access to their professional and academic peers.