A microwave or other radio frequency (RF) hyperthermia system and method with improved uniformity and selection of heating. The novel apparatus has a single applicator or an array of applicators excited by the RF/microwave sources and connecting with some kind of controlling and monitoring subsystems. It is used for ether hyperthermia or acupuncture to provide invasive and noninvasive medical treatment to the target inside a human body. The individual applicator consists of a central signal coaxial needle surrounded by a plurality of secondary needles to enclose the heated target. The applicator guides the wave to move forwardly further resulting in a penetration improvement, and also to reduce the backward reflection from the radiator end, thus to make the boundary of heating pattern clear-defined. Such a guided-wave acupuncture needles or like-needles array producing a quasi-TEM electromagnetic (EM) radiation makes even one individual radiation applicator have a capability of EM energy focus. The central part of the applicator forms a coaxial cable type antenna. It also has a tunable feature to vary the position of each needle and the resonance length of the coaxial needle radiator to make individual applicator create a variable thermal pattern. In addition, the frequency, amplitude, and relative phase from each applicator of the formed array system can be varied by the RF/microwave generator, amplifier, and phase shifter to create optimized heating patterns via the feedback of a real time temperature profile and image display through a computer control. Through the hollow needles it can provide three-dimensional infusion of therapeutic materials and three-dimensional temperature measurement.