电压纹波和电流模式对诊断X射线光谱及曝光量的影响。

Effects of voltage ripple and current mode on diagnostic x-ray spectra and exposures.

作者信息

Matsumoto M, Kubota H, Hayashi H, Kanamori H

机构信息

Department of Electrical Engineering, Osaka Prefectural College of Technology, Japan.

出版信息

Med Phys. 1991 Sep-Oct;18(5):921-7. doi: 10.1118/1.596736.

DOI:10.1118/1.596736

PMID:1961155

Abstract

The voltage-ripple dependence relationship on x-ray energy-spectral values (energy fluence per unit interval of photon energy) and exposures at 70-kV peak were obtained theoretically by using the semiempirical formula of emission spectra given by Birch and Marshall [Phys. Med. Biol. 24, 505 (1979)]. The calculations were performed with and without various thicknesses of aluminum. As the ripple increases, the energy-spectral values decrease as expected. When the ripple is large, however, energy-spectral values (per mAs) take the minimum values; therefore, the exposure (per mAs) also reaches the minimum value for the unsaturating current modes, contrary to expectation. The reasons for this phenomenon were clarified. Exposures clearly take the minimum value in 2-pulse units. This phenomenon was experimentally verified.

摘要

通过使用Birch和Marshall给出的发射光谱半经验公式[《物理医学与生物学》24, 505 (1979)]，从理论上获得了在70 kV峰值下电压纹波与X射线能谱值（每单位光子能量间隔的能量注量）和曝光量之间的依赖关系。计算在有和没有各种厚度铝的情况下进行。随着纹波增加，能谱值如预期那样降低。然而，当纹波较大时，能谱值（每毫安秒）取最小值；因此，对于不饱和电流模式，曝光量（每毫安秒）也达到最小值，这与预期相反。阐明了这种现象的原因。曝光量在2脉冲单元中明显取最小值。这一现象通过实验得到了验证。