To turn the advantage of energy measurement in x-ray transmission diagnosis into practice, we propose a novel detector for the estimation of x-ray energy distribution. This detector consists of several segment detectors arrayed in the direction of x-ray incidence. Each segment detector measures x-rays as current. With unfolding measured currents, the x-ray energy distribution is obtained. The practical application of this detector was verified by estimating the iodine thickness in an acryl phantom.

To turn the advantage of energy measurement in x-ray transmission diagnosis into practice, we propose a novel detector for the estimation of x-ray energy distribution. This detector consists of several segment detectors arrayed in the direction of x-ray incidence. Each segment detector measures x-rays as current. With unfolding measured currents, the x-ray energy distribution is obtained. The practical application of this detector was verified by estimating the iodine thickness in an acryl phantom.

The advantages of energy measurement of x-rays over current measurement in transmission radiography and computed tomography (CT) for detecting iodine contrast media are discussed. Simulation studies on both methods of measurement are carried out, followed by experiments. As data for energy measurement of x-rays, the event ratio of two energy regions with a K-edge of iodine between them is employed. The energy measurement method is immune to beam hardening, while current measurement suffers greatly with changes in x-ray tube voltage and thickness of the body under measurement. This method is useful in interventional radiology and in CT. It will also be useful for detecting other types of contrast medium.

A feasibility study of X-ray transmission measurements for contrast media with less exposure using filtered Xrays and their energy information is described. Based on measurements of the energy spectra of La-filtered X-rays, sensitivity to the contrast media and the relative quantity of dose exposure of filtered X-rays as the ratio to white Xrays are shown. The dose exposure for the measurement of iodine contrast media is reduced by more than 50% with a 400 µm thick La filter. By using a filter with atomic number close to that of iodine such as Cs and Ba, a greater reduction in dose exposure with a smaller increase in the current of the X-ray tube is expected.

No abstract