<p>Medical isotopes are the foundation material for nuclear medicine and are primarily produced through in-reactor irradiation. Neutron spectrum regulation is the main technical approach for enhancing the production of medical isotopes, and it requires determining the optimal neutron spectrum and quantifying the values of neutrons in different energy regions. We calculated the neutron energy region values for 20 medical isotopes (¹⁴C, ³²P, ⁴⁷Sc, ⁶⁰Co, ⁶⁴Cu, ⁶⁷Cu, ⁸⁹Sr, ⁹⁰Y, ⁹⁹Mo, ¹²⁵I, ¹³¹I, ¹⁵³Sm, ¹⁶¹Tb, ¹⁶⁶Ho, ¹⁷⁷Lu, ¹⁸⁶Re, ¹⁸⁸Re, ⁹²Ir, ²²⁵Ac, and ²⁵²Cf). The entire energy range was divided into 238 energy regions to improve the energy spectrum resolution, and both fast and thermal reactors were simulated to enhance universal applicability. A dataset of neutron energy region values across the entire energy range was built, which identifies the&#xa0;positive and negative-energy regions and guides the neutron spectrum regulation process during in-reactor medical isotope production. We conducted neutron spectrum regulation based on this dataset, which effectively improved the production efficiency of medical isotopes and demonstrated the correctness and feasibility of the dataset.</p>