A brachytherapy positioning and dosimetry system for brachytherapy plan verification and treatment procedures, comprising at least a radionuclide emitter applied from a brachytherapy afterloader, the system further comprises: • a base plate comprising a plurality of grooves, a mesh-work with a grid-shaped coordinate-scale linked to the mesh-work, and to a label marked on a brachytherapy phantom or patient's body; • a 3D-scanner comprising an arrangement of multiple scintillator-sensors operating as optical beacons installed within, at least, three needle-type catheters, those dedicated to being positioned either within a phantom for brachytherapy procedure plan verification, or within patient's body tissue under treatment, whereby said at least three needle-type catheters are installed into grooves of the base plate by their triangular allocation in the coordinate scale of the mesh-work; • fiberscopes connecting said scintillator-sensors, for transferring scintillators' signals for further processing; • the 3D-scanner further comprises semiconductor device-type radiation sensors as irradiation dosimeters, installed within said needle-type catheters together with the scintillator-sensors; • a control computer, configured at least to: o control operation of the 3D-scanner with the radionuclide emitter, o acquire the 3D-scanner data, o process the acquired 3D-scanner data, by applying triangulation technique on the signals of the radiation sensors and the scintillator sensors, to identify positioning of the radionuclide emitter within time-space-resolved coordinates, o measure the accumulated irradiation dose 3D-map within the time-space-resolved coordinates of the 3D-scanner, based on the signals from the dosimeters, • a base plate comprising a plurality of grooves, a mesh-work with a grid-shaped coordinate-scale linked to the mesh-work, and to a label marked on a brachytherapy phantom or patient's body; • a 3D-scanner comprising an arrangement of multiple scintillator-sensors operating as optical beacons installed within, at least, three needle-type catheters, those dedicated to being positioned either within a phantom for brachytherapy procedure plan verification, or within patient's body tissue under treatment, whereby said at least three needle-type catheters are installed into grooves of the base plate by their triangular allocation in the coordinate scale of the mesh-work; • fiberscopes connecting said scintillator-sensors, for transferring scintillators' signals for further processing; • the 3D-scanner further comprises semiconductor device-type radiation sensors as irradiation dosimeters, installed within said needle-type catheters together with the scintillator-sensors; • a control computer, configured at least to: o control operation of the 3D-scanner with the radionuclide emitter, o acquire the 3D-scanner data, o process the acquired 3D-scanner data, by applying triangulation technique on the signals of the radiation sensors and the scintillator sensors, to identify positioning of the radionuclide emitter within time-space-resolved coordinates, o measure the accumulated irradiation dose 3D-map within the time-space-resolved coordinates of the 3D-scanner, based on the signals from the dosimeters, o control operation of the 3D-scanner with the radionuclide emitter, o acquire the 3D-scanner data, o process the acquired 3D-scanner data, by applying triangulation technique on the signals of the radiation sensors and the scintillator sensors, to identify positioning of the radionuclide emitter within time-space-resolved coordinates, o measure the accumulated irradiation dose 3D-map within the time-space-resolved coordinates of the 3D-scanner, based on the signals from the dosimeters,