The original paper is in English. Non-English content has been machine-translated and may contain typographical errors or mistranslations. ex. Some numerals are expressed as "XNUMX".
Copyrights notice
The original paper is in English. Non-English content has been machine-translated and may contain typographical errors or mistranslations. Copyrights notice
X선 컴퓨터 단층촬영에서는 산란된 X선을 일반적으로 검출기 전면에 위치한 환자후 조준기를 이용해 제거한다. 본 논문에서는 산란된 X선이 컴퓨터 단층 촬영에서 감쇠 계수의 추정 정확도를 향상시킬 수 있는 가능성을 보여줍니다. 문제를 명확하게 하기 위해 우리는 하나의 감쇠 계수만 추정하면 되도록 컴퓨터 단층 촬영의 기하학적 구조를 균질한 재료로 구성된 얇은 원통으로 단순화했습니다. 그런 다음 XNUMX차 X선 외에 원통 주변의 여러 전용 토로이달 검출기로 산란된 X선을 측정하여 감쇠 계수의 추정 정확도를 향상시키는 몬테카를로 수치 실험을 수행했습니다. 우리는 실험 결과를 설명하기 위해 이론적 분석을 추가로 제시합니다. 우리는 T-접합(즉, T-접합 모델)을 사용하여 광자 전송을 XNUMX차 구성 요소와 산란 구성 요소로 나누는 모델을 사용했습니다. 이 분할은 감쇠 계수와 관련하여 처리됩니다. 직렬로 연결된 여러 T 접합 모델을 사용하여 여러 산란 검출기의 경우를 모델링했습니다. 추정 정확도는 효율적인 추정량, 즉 Cramer-Rao 하한의 분산에 따라 평가되었습니다. 산란검출기 개수가 증가할수록 분산이 감소하는 것을 확인했는데, 이는 산란형 X선을 활용하면 환자의 방사선량을 줄일 수 있음을 의미한다.
Naohiro TODA
Aichi Prefectural University
Tetsuya NAKAGAMI
DENSO CREATE INC.
Yoichi YAMAZAKI
Kwansei Gakuin University
Hiroki YOSHIOKA
Aichi Prefectural University
Shuji KOYAMA
Nagoya University
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Naohiro TODA, Tetsuya NAKAGAMI, Yoichi YAMAZAKI, Hiroki YOSHIOKA, Shuji KOYAMA, "Using Scattered X-Rays to Improve the Estimation Accuracy of Attenuation Coefficients: A Fundamental Analysis" in IEICE TRANSACTIONS on Fundamentals,
vol. E101-A, no. 7, pp. 1101-1114, July 2018, doi: 10.1587/transfun.E101.A.1101.
Abstract: In X-ray computed tomography, scattered X-rays are generally removed by using a post-patient collimator located in front of the detector. In this paper, we show that the scattered X-rays have the potential to improve the estimation accuracy of the attenuation coefficient in computed tomography. In order to clarify the problem, we simplified the geometry of the computed tomography into a thin cylinder composed of a homogeneous material so that only one attenuation coefficient needs to be estimated. We then conducted a Monte Carlo numerical experiment on improving the estimation accuracy of attenuation coefficient by measuring the scattered X-rays with several dedicated toroidal detectors around the cylinder in addition to the primary X-rays. We further present a theoretical analysis to explain the experimental results. We employed a model that uses a T-junction (i.e., T-junction model) to divide the photon transport into primary and scattered components. This division is processed with respect to the attenuation coefficient. Using several T-junction models connected in series, we modeled the case of several scatter detectors. The estimation accuracy was evaluated according to the variance of the efficient estimator, i.e., the Cramer-Rao lower bound. We confirmed that the variance decreases as the number of scatter detectors increases, which implies that using scattered X-rays can reduce the irradiation dose for patients.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/transfun.E101.A.1101/_p
부
@ARTICLE{e101-a_7_1101,
author={Naohiro TODA, Tetsuya NAKAGAMI, Yoichi YAMAZAKI, Hiroki YOSHIOKA, Shuji KOYAMA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Using Scattered X-Rays to Improve the Estimation Accuracy of Attenuation Coefficients: A Fundamental Analysis},
year={2018},
volume={E101-A},
number={7},
pages={1101-1114},
abstract={In X-ray computed tomography, scattered X-rays are generally removed by using a post-patient collimator located in front of the detector. In this paper, we show that the scattered X-rays have the potential to improve the estimation accuracy of the attenuation coefficient in computed tomography. In order to clarify the problem, we simplified the geometry of the computed tomography into a thin cylinder composed of a homogeneous material so that only one attenuation coefficient needs to be estimated. We then conducted a Monte Carlo numerical experiment on improving the estimation accuracy of attenuation coefficient by measuring the scattered X-rays with several dedicated toroidal detectors around the cylinder in addition to the primary X-rays. We further present a theoretical analysis to explain the experimental results. We employed a model that uses a T-junction (i.e., T-junction model) to divide the photon transport into primary and scattered components. This division is processed with respect to the attenuation coefficient. Using several T-junction models connected in series, we modeled the case of several scatter detectors. The estimation accuracy was evaluated according to the variance of the efficient estimator, i.e., the Cramer-Rao lower bound. We confirmed that the variance decreases as the number of scatter detectors increases, which implies that using scattered X-rays can reduce the irradiation dose for patients.},
keywords={},
doi={10.1587/transfun.E101.A.1101},
ISSN={1745-1337},
month={July},}
부
TY - JOUR
TI - Using Scattered X-Rays to Improve the Estimation Accuracy of Attenuation Coefficients: A Fundamental Analysis
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1101
EP - 1114
AU - Naohiro TODA
AU - Tetsuya NAKAGAMI
AU - Yoichi YAMAZAKI
AU - Hiroki YOSHIOKA
AU - Shuji KOYAMA
PY - 2018
DO - 10.1587/transfun.E101.A.1101
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E101-A
IS - 7
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - July 2018
AB - In X-ray computed tomography, scattered X-rays are generally removed by using a post-patient collimator located in front of the detector. In this paper, we show that the scattered X-rays have the potential to improve the estimation accuracy of the attenuation coefficient in computed tomography. In order to clarify the problem, we simplified the geometry of the computed tomography into a thin cylinder composed of a homogeneous material so that only one attenuation coefficient needs to be estimated. We then conducted a Monte Carlo numerical experiment on improving the estimation accuracy of attenuation coefficient by measuring the scattered X-rays with several dedicated toroidal detectors around the cylinder in addition to the primary X-rays. We further present a theoretical analysis to explain the experimental results. We employed a model that uses a T-junction (i.e., T-junction model) to divide the photon transport into primary and scattered components. This division is processed with respect to the attenuation coefficient. Using several T-junction models connected in series, we modeled the case of several scatter detectors. The estimation accuracy was evaluated according to the variance of the efficient estimator, i.e., the Cramer-Rao lower bound. We confirmed that the variance decreases as the number of scatter detectors increases, which implies that using scattered X-rays can reduce the irradiation dose for patients.
ER -