The present application relates to a catheter apparatus including a tubular member, and four or more fluid-flow pipe members, each having a proximal end and a distal end, and each being disposed around a periphery of the tubular member along an axial direction thereof. Each of the four or more fluid-flow pipe members is provided with an independent positioning member at the distal end thereof, and the number of positioning members is four or more. A brachytherapy system and a method of reducing area of radiation exposure of normal tissue in a brachytherapy treatment using the catheter apparatus are also disclosed.