Indeed a lot of ICT professionals tend to have a background in Computing, Science, Technology, Maths and Engineering, so to have a qualification in one of those fields would be very useful.
However ICT is a lot broader than that, encompassing information management and knowledge sharing, communication transmission (i.e.TV, Radio, Internet, Print, mobile and telephone) and technology ( e.g. computers, softwares, mobile technologies, robotics etc).
As far as i am aware there is no ICT professional body ( or at least one that is vocal) that governs and regulates those in ICT. So, becoming an ICT professional is not complicated as long as you gain the technical expertise in any of the areas mentioned above.
The term ICT only became popular a few years ago as professionals realised that IT (Infomation Technology) involved much more than just computer systems and infact needed a broader perspective when handling and supporting people and corporate information needs.
I hope this contribution helps