How Can I Get Into Radiology As A Career In South Africa?

You would have to study radiology at a university. Since I don't know which city you are in, it may be better to call up the website of the university nearest you, or the one you are keen on attending. Wits in Johannesburg,Pretoria University, UCT in Cape Town, or the University of the Western Cape, Stellenbosch, and Durban University. These are the main ones.
You could go to the site, and look at the degree offered, and then go to the admission requirements page, and apply for the prospectus and forms to be sent to you, from the two you like the most.
You need to do this by the middle of the year, before the following year, that you plan to start studying in
You need to know, if you are still at school, that you will need
good marks in maths and science at Matric higher grade.
The sooner that you make the decision, and send your completed forms and certificates off the better, as they are often more applicants than places.
Good Luck.