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This work focuses on the development of a specific metrology and dosimetry methodology for systems utilizing low-energy X-ray beams. The study is motivated by the increasing use of portable X-ray equipment and the lack of established dosimetry protocols for these systems, which are currently calibrated only by their manufacturers. The study's methodology involved the use of parallel-plate ionization chambers and Fricke gel, alongside X-ray emission systems. Quality control tests were performed for the parallel-plate ionization chambers, including repeatability, stability, leakage current, and polarity effect. The Fricke Xylenol Gel (FXG) dosimeter was prepared and calibrated at the low-energy X-ray radiation qualities recommended by the BIPM for radiotherapy and subsequently used in the dosimetry of a portable X-ray device. Measurement uncertainties were analyzed, highlighting the 2% calibration uncertainty of the reference ionization chamber as the primary source. The results demonstrate that the parallel-plate ionization chambers presented reliability within the limits specified by the IEC 60731 standard. The use of the FXG dosimeter, combined with optical computed tomography, proved effective for characterizing low-energy radiation beams, providing a detailed map of the dose distribution. In conclusion, this work established a robust methodology for the dosimetry of portable X-ray systems. The research validates the use of the Fricke gel dosimeter and optical tomography to map dose distribution, which is essential for quality control and treatment planning in electronic brachytherapy equipment. Future studies should include comparisons with treatment planning data for a more rigorous and complete validation.