A high-purity germanium spectrometer system was used to determine primary x-ray spectra over the 45--90-kVp region. Methods were devised for producing and examining spectra stimulating diagnostic conditions without operating the x-ray generator at high current levels. The techniques used to correct the experimental data and produce a photon fluence spectrum are discussed. The results, presented graphically and in tables, have been normalized to yield the relative number of photons per 2-keV interval. Methods for converting a normalized spectrum into a photon fluence spectrum that will produce an exposure of 1 R are presented. The analytical model and procedures used to calculate the K-escape fraction are discussed.