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Reduction of patient dose at medical x-ray diagnosis using scattered x rays.

Research Project

Project/Area Number 08680524
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field エネルギー学一般・原子力学
Research InstitutionFukui University of Technology

Principal Investigator

KANAMORI Hitoshi  Fukui University of Technology, Electrical Engineering, professor, 工学部, 教授 (70027770)

Co-Investigator(Kenkyū-buntansha) MATSUMOTO Masao  Osaka University, Faculty of Medicine, associate professor, 医学部, 助教授 (50149944)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywordsmedical x-ray image / image quality / patient dose / granularity / scattered x rays
Research Abstract

(1)Measurement of x-ray spectra
We have attempted to perform the direct measurement of x-ray spectra using low-cost CdTe and CdZnTe detectors, which have been developed recently. The results obtained with CdTe detector were less exact than those with a Ge detector, but those with CdZnTe detector agreed with it.
(2)Effects of anti-scatter grids on x-ray spectra and radiographic image quality
By using a conical collimator and a lead beam stopper, primary and scattered x-ray photon spectra through an object and an anti-scatter grid (addreviated as grid, hereafter) were measured separately, varying the irradiation field area. From these results, we obtained the grid ratio, scatter ratio and Bucky factors. The scatter ratio varied with tube voltage but Bucky factors did not. At any spatial frequency, the effects of grids for removing scattered x-rays were almost constant for the tube voltage.
(3)Optimum tube voltage of radiographs obtained by psychophysical analysis
We proposed a new method for … More determining the optimum tube voltage of a chest radiograph using psychophysical analysis. The optimum density range of screen-film system was obtained from gradient curve and minimum perceptible contrasts. An optimum tube voltage, by which the highest density in the lung-field and the lowest density in the mediastinum just covered the optimum density range, was obtained using x-ray photon spectrum and sensitivity spectrum of the screen.
(4)Modulation transfer function and Wiener spectra for a screen-film system
We have obtained the tube voltage dependence of the modulation transfer function (MTF) of a rare-earth screen-film system. The values of the MTFs for the front and back sides at spatial frequencies of less than 3mm^<-1> decreased with the tube voltage. We showed that to explain this phenomenon, not only K-x rays but coherent and incoherent scattered x-ray photons yielded in the screens had to be taken into consideration.
The influence of the crossover effect on the tube voltage dependence of the Wiener spectrum of the quantum mottle for the front and back emulsion has been investigated. It was found that if the crossover effect was appropriately included in the radiographs, the patient exposure and the Wiener spectrum of the quantum mottle could be reduced. Less

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] H.Arimura: "X-ray tube voltage dependence of Wiener spectra of quantum mottle obtained by detective quantum eddiciencies of a screen" Optical Engineering. 35・4. 926-937 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] A.Asai: "Evaluation of radiographic mottle using a single drequency value of the psychophysical Wiener spectrum" Journal of Photographic Science. 44・3. 89-92 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] A.Takigawa: "Effects of anti-scatter grid on X-ray spectrum and radiographic contrast" Journal of Photographic Science. 44・3. 93-98 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 松本 政雄: "CdTe,CdZnTe検出器を用いて測定した診断用X線スペクトルの補正" 放射線. 22・3. 63-72 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] H.Arimura: "Influence of crossover effect on X-ray tube voltage dependence of quantum mottle" Journal of Photographic Science. 44・6. 249-256 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 浅井 義行: "心理物理的解析から求めた胸部X線写真の最適撮影条件" 日本写真学会雑誌. 60・3. 189-195 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] H.Arimura, T.Ikari, M.Okamoto, N.Nakamori, H.Kanamori, H.Kubota, M.Matsumoto and A.Takigawa: "X-ray tube voltage dependence of Wiener spectra of quantum mottle obtained by determining detective quantum efficiencies of a screen" Optical Engineering. 35[4]. 926-937 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Asai, Y.Ozaki, H.Kubota, M.Matsumoto and H.Kanamori: "Evaluation of radiographic mottle using a single frequency value of the psychophysical Wiener spectrum" Journal of Photographic Science. 44[3]. 89-92 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] A.Takigawa, Y.Nishikawa, H.Kubota, Y.Ogata, M.Matsumoto and H.Kanamori: "Effects of antiscatter grid on x-ray spectrum and radiographic contrast" Journal of Photographic Science. 44[3]. 93-98 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Matsumoto, H.Kanamori, T.Toragaito and A.Taniguchi: "Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors" Ionization Radiation. 22[3]. 63-72 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] H.Arimura, T.Okawa, T.Ikari, M.Okamoto, H.Kubota, M.Matsumoto, A.Takigawa, N.Nakamori and H.Kanamori: "Influence of the crossover effect on x-ray tube voltage dependence of quantum mottle" Journal of Photographic Science. 44[6]. 178-186 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Y.Asai, Y.Tanabe, Y.Ozaki, H.Kubota, M.Matsumoto and H.Kanamori: "Optimum tube voltage of chest radiographs obtained by psychophysical analysis" J.Soc.Photogr.Sci.Thechnol.Japan. 60[3]. 182-188 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 浅井義行: "心理物理的解析を用いたX線写真粒状の評価" 医用画像情報学会雑誌. 14・2. 83-94 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 浅井義行: "心理物理的解析から求めた胸部X線写真の最適撮影条件" 日本写真学会雑誌. 60・3. 189-195 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Matsumoto: "Direct measurement of mammographic X-ray spectra using CdZnTe detector" Medical & Biological Engineering & Computing. 35・S2. 691 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] H.Kanamori: "Evaluation of radiographic mottle using psychophysical RMS granularity" Medical & Biological Engineering & Computing. 35・S2. 1131 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] H.Kubota: "Measurement of angular distribution for scatlered X-rag spectra" Medical & Biological Engineering & Computing. 35・S2. 1143 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] T.Tsunoo: "Influence of in correct placement of the defocused grid on au X-ray image formation" SPIE Proceedings. 3336(印刷中). 9 (1998)

    • Related Report
      1997 Annual Research Report
  • [Publications] H.Arimura: "X-ray tube voltage dependence of Wiener spectra of quantum mottle obtained by detective quantum efficiencies of a screen" Optical Engineering. 35.4. 926-937 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] A.Asai: "Evaluation of radiographic mottle usiung a single frequency value of the psychophysical Wiener spectrum" Journal of Photographic Science. 44.3. 89-92 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] A.Takigawa: "Effects of antiscatter grid on X-ray spectrum and radiographic contrast" Journal of Photographic Science. 44.3. 93-98 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 松本 政雄: "CdTe.CdZnTe検出器を用いて測定した診断用X線スペクトルの補正" 放射線. 22.3. 63-72 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] H.Arimura: "Influence of crossover effect on X-ray tube voltage dependence of quantum mottle" Journal of Photographic Science. 44.6. 249-256 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 浅井 義行: "心理物理的解析から求めた胸部X線写真の最適撮影管電圧" 日本写真学会雑誌. 60・3(印刷中). (1997)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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