You can suscribe a professional insurance from Escapade (http://www.worldescapade.com/en/reporterinsurance.aspx and http://en.rsf.org/insurance-for-freelance-17-04-2007,21746.html), the insurance service of Reporters without borders.
I used it twice for two trips in Afghanistan April 2010 and May 2011.
I was not injured so I can’t tell anything about efficiency.
It has a fixed amount which cover every emergency/health situation and a pay-as-you-wish(can) extra for you and/or your family in case of death or mutilation.
is a nice guy, you can contact him here : firstname.lastname@example.org