FIELD: medicine.SUBSTANCE: group of the inventions relates to medicine and can be used when it is necessary to deliver the agent from the source to the target tissue of the mammal body； the invention comprises the catheter containing the first elongated tubular element having the near aperture and far end sidewall, the second elongated tubular element made to be connected to the source and having the part passing through the first tubular element and the far end standing proud of the end sidewall； the tubular elements form the circular cavity in the first tubular element and the stiffening element with at least part of it located in the circular cavity providing the stiffness and ease in accurate installation of the far end relatively the target tissue, this part of the stiffening element can be removed from the circular cavity after such an installation without removing the second elongated tubular element from the organism of the mammal animal； the first elongated tubular element and the second elongated tubular element are connected at the far end of the first elongated tubular element to the effect that their cavities are not connected； the description of the catheter variants different in the execution of the stiffening element is given herein； the variants of the agent delivery methods to the target tissue which differ in techniques of the catheter stiffness reduction are also described herein.EFFECT: invention allows to secure the accurate delivery of the agent to the target tissue due to provision of stiffness and reduction of the run-back of the fluid along the external surface of the catheter thanks to the development of the catheter structural components.13 cl, 15 dwgГруппа изобретений относится к медицине и может быть использована при необходимости доставки агента от источника к ткани-мишени организма млекопитающего. Предложен катетер, который содержит первый удлиненный трубчатый элемент, имеющий ближнее отверстие и дальнюю концевую стенку； второй удли
