1. A system for endoscopic nuclear imaging, which comprises: a movable endoscopic nuclear probe which includes a collimator, a crystal for detecting radioactive radiation, and a photomultiplier coupled to the crystal, wherein the endoscopic nuclear probe has an elongated body with a longitudinal axis (X), which is designed to be inserted into the body of a patient, wherein the crystal and the collimator are arranged on the elongated body of the endoscopic nuclear probe, wherein the collimator surrounds the crystal and the photomultiplier, wherein the collimator has a laterally directed opening which delimits a detection angle through a field of view of the collimator, and wherein the field of view has an axis (Y), wherein the axis (Y) of the field of view of the collimator is inclined with respect to the axis (X) of the elongated body of the endoscopic nuclear probe, and wherein the field of view of the collimator is limited anisotropically with respect to the longitudinal axis X of the elongated body; means for determining the position and orientation of the elongated body of the endoscopic nuclear probe; and an evaluation unit, which includes: i) an interface system for transmitting data with information about the detected radioactive radiation, and information about the position and orientation of the elongated body of the endoscopic nuclear probe to the evaluation unit; ii) a data storage section for storing the information; iii) means for synchronising the information about the position and orientation of the elongated body of the endoscopic nuclear probe with the information about the radiation detected by the endoscopic nuclear probe; iv) means for computationally determining an actual position and actual orientation of the elongated body of the endoscopic nuclear probe; v) a program storage section with a program for repeated determination of at least one quality value Q with regards to the imaging from the information mentioned; and vi) an output system for outputting a three-dimensional reproduction of the information about the actual position and actual orientation of the elongated body of the endoscopic nuclear probe and information about the detected radiation.