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

Kanno, Ikuo; Uesaka, Akio; Nomiya, Seiichiro; Onabe, Hideaki

doi:10.1080/18811248.2008.9711410

Cited by 20 publications

(20 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference between the CT values of acrylic and iodine regions is the maximum in the energy range G 3 , k0g., energy range higher than the K-edge of iodine. The CT value profiles obtained by the X-ray events for G 3 …”

Section: (4) Spectrum Survey Methodsmentioning

confidence: 99%

“…The energy resolved CT measurements with using a CdZnTe detector demonstrated advantages over the conventional current measurement method in nearly twofold better iodine contrast, and insensitivity to the beam hardening effect 3) . The measurement time, however, was very long: nearly 10 minutes for one z/T position of the first generation CT measurement.…”

Section: K0 " Kpvtqfwevkqp"mentioning

confidence: 99%

“…The dimensions of each Si(Li) detector is 10 × 10 × 1 mm 3 . These Si(Li) segment detectors are operated at room temperature without applying bias voltage as the mean free paths of electrons and holes are sufficiently long enough to arrive at each electrodes.…”

Section: Kk0" Rtkpekrng"qh"vtcpuzgpf"fgvgevqt"mentioning

confidence: 99%

See 2 more Smart Citations

A transXend Detector - Principle and Applications

Kanno

2012

Progress in Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

A transXend detector was developed to use energy information of X-rays in computed tomography (CT). In this paper, the operation principle of the transXend detector is described first. The way of applying it to CT is following. Some possible fields to apply it are shown. MG[YQTFU<"eqorwvgf"vqoqitcrj{."gpgti{"kphqtocvkqp."wphqnfkpi."Z/tc{u."eqpvtcuv"cigpv" " " K0 " Kpvtqfwevkqp"In computed tomography (CT) measurements, contrast agent such as iodine is injected into blood vessel (contrast enhanced CT) to make a cancer tissue visible with the absorption of X-rays by iodine. The portion of blood vessel in the cancer tissue is higher than the one of normal tissue, and as a result, iodine concentration in the cancer tissue is higher than the one of normal tissue. The iodine-marked cancer tissue absorbs X-rays more than normal tissue and is observed easily.The contrast enhanced CT, however, has two major shortcomings: the side effect of contrast agent 1) , and a "beam hardening effect"2) . The beam hardening effect happens when a subject is thick, and an X-ray tube voltage is high: after passing a thick subject, the number of X-rays, which are sensitive to the absorption by iodine, becomes less. As a result, the X-ray absorption by iodine cannot be seen very clearly.For avoiding these two disadvantages, the author employed the energy information of X-rays in CT measurement. The energy resolved CT measurements with using a CdZnTe detector demonstrated advantages over the conventional current measurement method in nearly twofold better iodine contrast, and insensitivity to the beam hardening effect 3) . The measurement time, however, was very long: nearly 10 minutes for one z/T position of the first generation CT measurement.In the X-ray CT, transmission measurement should be done quickly, if the subject is a human being. With this condition, the X-rays have been measured as electric current, k0g., the energy information of X-rays is discarded.In the energy measurement of photons such as X-rays and gamma-rays, we have a limitation in counting rate in any type of radiation detectors. We have to wait for the charges, g0i., electrons and ions, electrons and holes, arrive at positive and negative electrodes, respectively.Most radiation detectors pursue the ability of measuring the energy of radiation as precise as possible. For high precision energy measurement of photons, photons should be collimated to limit the incident rate to the radiation detector. The energy measurement and high-flux photon measurement are not compatible.In applications, the precise energy information, however, is not always necessary. Besides, it is not possible to measure the energy of high flux photons by conventional radiation detectors. Nevertheless, in some cases, even rough energy distribution of photons could bring useful information.To make the energy resolved CT as a practical measurement method, the author developed a new detector, called a transXend detector. This transXend detector consists of several segment detectors, which are aligned ...

show abstract

Section: (4) Spectrum Survey Methodsmentioning

confidence: 99%

Section: K0 " Kpvtqfwevkqp"mentioning

confidence: 99%

See 1 more Smart Citation

A transXend Detector - Principle and Applications

Kanno

2012

Progress in Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…1) However, conventional measurement of X-ray energy is not suitable for practical CT because it is time-consuming. For a quick acquisition of the X-ray energy distribution, a new detector, which measures X-rays as current and gives the X-ray energy distribution, was invented by the present authors; 2) this detector was named the transXend detector.…”

Section: Introductionmentioning

confidence: 99%

Using X-ray Energy Information in CT Measurement of a Phantom with an Al Region

Minami

Imamura

Kanno

et al. 2011

J. Nucl. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

X-ray computed tomography (CT) using X-ray energy information has been studied by the present authors on acrylic phantoms containing an iodine contrast medium. To observe a human body, however, it is necessary to consider the bone. In this paper, CT measurements were made on a phantom with regions of both iodine and aluminum, which was used as a substitute for the bone. A filtered back-projection method and a maximum likelihood-expectation maximization method were employed for image reconstruction.

show abstract

“…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. 5) The X-ray energy measurement method, however, is hard to apply to CT. Conventional X-ray energy measurements are performed in pulse mode, which requires a relatively long time to obtain an X-ray energy spectrum with sufficient statistics.…”

Section: Introductionmentioning

confidence: 99%

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

Hashimoto

Ohtaka

Ara

et al. 2009

Journal of Nuclear Science and Technology

Self Cite

View full text Add to dashboard Cite

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.

show abstract

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

Cited by 20 publications

References 10 publications

A transXend Detector - Principle and Applications

A transXend Detector - Principle and Applications

Using X-ray Energy Information in CT Measurement of a Phantom with an Al Region

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

Contact Info

Product

Resources

About