320 列CT 装置のX 線スペクトル測定時に使用する円柱カーボン散乱体の適切な長さに関する検討 Investigation of the Columnar Carbon-scatterer Length for X-ray Spectral Measurement on 320-slice Computed Tomography

A short length scatterer is adopted to measure the X-ray spectrum of computed tomography (CT) equipment with a wide irradiation field in the body axis direction. The purpose of this study is to compare X-ray spectra measured using different length scatterers and determine the most appropriate length for the scatterer. 320-slice CT equipment (Aquilion ONE) was used in this study. Circular carbon rods (3 cm diameter) with five different lengths (1‒16 cm) were used as scatterers. The effect of the beam hardening phenomenon from different length carbon rods was evaluated according to the effective energy. The measurement accuracy for photon information was also evaluated based on the photon count corresponding to the characteristic X-ray. As a result, the beam hardening effect was scarcely observed when the 1 cm long scatterer was used, and the number of the photons measured for the characteristic X-ray was the most. Therefore, it was concluded that the 1 cm long circular carbon rod scatterer was the most suitable.

A short length scatterer is adopted to measure the X-ray spectrum of computed tomography (CT) equipment with a wide irradiation field in the body axis direction. The purpose of this study is to compare X-ray spectra measured using different length scatterers and determine the most appropriate length for the scatterer. 320-slice CT equipment (Aquilion ONE) was used in this study. Circular carbonrods (3 cm diameter) with five different lengths (1–16 cm) were used as scatterers. The effect of the beam hardening phenomenon from different length carbon rods was evaluated according to the effective energy. The measurement accuracy for photon information was also evaluated based on the photon count corresponding to the characteristic X-ray. As a result, the beam hardening effect was scarcely observed when the 1 cm long scatterer was used, and the number of the photons measured for the characteristic X-ray was the most. Therefore, it was concluded that the 1 cm long circular carbon rod scatterer was the most suitable.