title: Long-term stability of beam quality and output of conventional X-ray units.
abstract: 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.
authors: Department of Radiology, Shiga Medical Center for Children, 5-7-30 Moriyama, Moriyama City, Shiga, 524-0022, Japan, ntoki@blue.plala.or.jp.
authors: Atsushi
authors: A
authors: Fukuda
authors: Kosuke
authors: K
authors: Matsubara
authors: Tosiaki
authors: T
authors: Miyati
mesh_terms: D006801:Humans; D007564:Japan; D011786:Quality Control; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000295:instrumentation*; D012189:Retrospective Studies; D013679:Technology, Radiologic / Q000295:instrumentation* / Q000379:methods*; D014965:X-Rays