@article{oai:kanazawa-u.repo.nii.ac.jp:00013875,
 author = {Fukuda, Atsushi and Matsubara, Kosuke and Miyati, Toshiaki},
 issue = {1},
 journal = {Radiological Physics and Technology},
 month = {Jan},
 note = {Conventional diagnostic X-ray units are used for radiographic imaging in many countries. For obtaining entrance surface doses, a numerical dose determination method has been applied in Japan. Although this technique is effective, it has to account for errors, particularly fluctuations, due to the beam quality and output of X-ray tubes. As a part of our quality control procedures, we recorded the entrance surface air kerma, tube voltage, and half-value layer measurements made for four diagnostic X-ray tubes over a 103-week period. The entrance surface air kerma for one of the four X-ray tubes had increased significantly by 11.4 % over 1 year from its initial setting, whereas the tube voltages and half-value layers did not deviate significantly from their initial values. Medical physicists and radiological technologists should be aware of this fluctuation for diagnostic X-ray tubes and take it into consideration when calculating the entrance surface air kerma. © 2014 Japanese Society of Radiological Technology and Japan Society of Medical Physics., 発行後1年より全文公開},
 pages = {26--29},
 title = {Long-term stability of beam quality and output of conventional X-ray units},
 volume = {8},
 year = {2015}
}