Energy subtraction method with filtered X-rays for the detection of contrast media

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.

Section: Comparison Of Current and Energy Measurement Methodsmentioning

confidence: 99%

Section: Experimental Studymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Energy Measurement of X-rays in Computed Tomography for Detecting Contrast Media

Kanno¹,

Uesaka

Nomiya³

et al. 2008

“…[1][2][3][4] When the ES method was applied to computed tomography (CT), beam-hardening artifacts were eliminated. With the conventional current X-ray measurement method, CT values for contrast media became lower with higher X-ray tube voltages and with thicker subjects.…”

Section: Introductionmentioning

confidence: 99%

Simulation Study on Unfolding Methods for Diagnostic X-rays and Mixed Gamma Rays

Hashimoto

Ohtaka

Ara

et al. 2009

A photon detector operating in current mode that can sense X-ray energy distribution has been reported. This detector consists of a row of several segment detectors. The energy distribution is derived using an unfolding technique. In this paper, comparisons of the unfolding techniques among error reduction, spectrum surveillance, and neural network methods are discussed through simulation studies on the detection of diagnostic X-rays and gamma rays emitted by a mixture of 137 Cs and 60 Co. For diagnostic X-ray measurement, the spectrum surveillance and neural network methods appeared promising, while the error reduction method yielded poor results. However, in the case of measuring mixtures of gamma rays, the error reduction method was both sufficient and effective.

“…Previously, we proposed a filtered x-ray energy subtraction (FIX-ES) method in which the energy of an individual x-ray was measured for the detection of iodine contrast media; 1,2) in conventional x-ray diagnosis, x-rays are measured as electrical current. The x-ray events in two energy ranges, which were lower and upper energies of the K-edge of the iodine contrast media, were employed as energy subtraction (ES) data.…”

Section: Introductionmentioning

confidence: 99%

A Current-Mode Detector for Unfolding X-ray Energy Distribution

Kanno

Imamura

Mikami

et al. 2008

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.