Automatic Contrast Agent Extraction System with Dual Energy CT

• Project/Area Number: 16K19231
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Medical Physics and Radiological Technology
• Research Institution: Hiroshima University
• Principal Investigator: Kawahara Daisuke 広島大学, 病院(医), 診療放射線技師 (20630461)
• Research Collaborator: TANAKA Sodai
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000); Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 放射線治療 / 治療計画 / 造影剤 / 線量計算 / Dual energy CT / 電子密度 / 単色X線CT値 / モンテカルロ計算 / 実効原子番号 / 医療・福祉 / 放射線 / X線

Outline of Final Research Achievements

In dual-energy CT (DECT), various information such as electron density, effective atomic number, and monochromatic X-ray CT value can be obtained. Using this information, we created a contrast agent map. And we constructed a system that allows us to identify the region where the contrast agent is present from the image and to assign the concentration accurately. The dose difference at 2 mg / ml, which is 3% or more of the contrast agent identification method, was within 2% and was not a significant difference. Furthermore, it was suggested that a dose calculation system incorporating a contrast agent identification method should be used if the contrast agent is contained at particularly high concentrations. We will study the results of this research so that it can be generalized, and promote the spread as part of a treatment planning system for high precision radiation therapy.

Academic Significance and Societal Importance of the Research Achievements

本研究では、造影剤を使用して検査（CT）を行った場合に画像上における造影剤で病変が白く染まった領域を抽出可能になります。これによって腫瘍のみをしっかりと把握できます。放射線治療においては病変領域に対して放射線を照射する領域を設定しますが、本造影剤特定システムを使用することで半自動的に腫瘍のみを設定でき、さらに造影剤が含まれる領域は人体に存在する物質とは異なるため造影剤として割り当てて計算を行わなければ線量差が生じてしまいます。本システムを使用し造影剤領域をしっかりと判定できれば正確に物質を割り当てて計算が可能となり、より正確かつ適切な線量投与が可能となります。

Research Products

• [Journal Article] Automatic contrast medium extraction system using electron density data with dual-energy CT (2018)
  • Author(s): Kawahara D, Ozawa S, Tanaka S, Yokomachi K, Higaki T, Saito A, Miki K, Fujioka C, Ohno Y, Ohno Y, Kimura T, Murakami Y, Nagata Y
  • Journal Title: The British Journal of Radiology Volume: 90 Issue: 1090 Pages: 1090-1090
  • DOI: 10.1259/bjr.20180396
  • Peer Reviewed
• [Journal Article] Energy spectrum and dose enhancement due to the depth of the Lipiodol position using flattened and unflattened beams (2018)
  • Author(s): Kawahara D, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Hioki K, Nakashima T, Ohno Y, Murakami Y and Nagata Y
  • Journal Title: Reports of Practical Oncology and Radiotherapy Volume: 23 Issue: 1 Pages: 50-56
  • DOI: 10.1016/j.rpor.2017.12.004
  • Peer Reviewed
• [Journal Article] Relative biological effectiveness study of Lipiodol based on microdosimetric-kinetic model (2018)
  • Author(s): Kawahara D, Nakano H, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Ohno Y, Murakami Y and Nagata Y
  • Journal Title: Physica Medica Volume: 46 Pages: 89-95
  • DOI: 10.1016/j.ejmp.2018.01.018
  • Peer Reviewed
• [Journal Article] Tolerance levels of CT number to electron density table for photon beam in radiotherapy treatment planning system (2018)
  • Author(s): Nakao M, Kawahara D, Ozawa S, Yamada K, Hosono F, et al.
  • Journal Title: Journal applied clinical medical physics Volume: 19 Issue: 1 Pages: 271-75
  • DOI: 10.1002/acm2.12226
  • Peer Reviewed
• [Journal Article] Effect of secondary electron generation on dose enhancement in Lipiodol with and without a flattening filter (2018)
  • Author(s): Kawahara D, Ozawa S, Saito A, Kimura T, et al.
  • Journal Title: Journal applied clinical medical physics Volume: 19 Issue: 2 Pages: 211-217
  • DOI: 10.1002/acm2.12282
  • Peer Reviewed
• [Journal Article] Accuracy of the raw-data-based effective atomic numbers and monochromatic CT numbers for contrast medium with a dual-energy CT technique (2017)
  • Author(s): Kawahara D, Ozawa S, Yokomachi K, Tanaka S, et al.
  • Journal Title: The British Journal of Radiology Volume: 91 Pages: 1082-1082
  • DOI: 10.1259/bjr.20170524
  • Peer Reviewed
• [Journal Article] Dosimetric Impact of Lipiodol in Stereotactic Body Radiation Therapy on Liver after Trans-arterial Chemoembolization (2017)
  • Author(s): Kawahara D, Ozawa S, Saito A, Nishio T, et al.
  • Journal Title: Medical Physics Volume: 44 Issue: 1 Pages: 342-348
  • DOI: 10.1002/mp.12028
  • Peer Reviewed
• [Presentation] Contrast medium extraction system using direct-electron density- CT number method and dual CT number method with Dual energy-CT (2018)
  • Author(s): Kawahara D, Ozawa S, Tanaka S, Yokomachi K, Higaki T, Saito A, Miki K, Fujioka C, Ohno Y, Ohno Y, Kimura T, Murakami Y, Nagata Y
  • Organizer: The 3rd International Conference on Radiological Science and Technology (ICRST)
  • Int'l Joint Research
• [Presentation] Contrast medium extraction method using raw-data based electron density with Dual energy-CT (2018)
  • Author(s): Kawahara D, Ozawa S, Tanaka S, Yokomachi K, Higaki T, Saito A, Miki K, Fujioka C, Ohno Y, Ohno Y, Kimura T, Murakami Y, Nagata Y
  • Organizer: ESTRO37
  • Int'l Joint Research
• [Presentation] Accuracy of the effective atomic numbers and theoretical monochromatic CT numbers for contrast medium with raw-data based dual-energy CT (2018)
  • Author(s): Kawahara D, Ozawa S, Tanaka S, Yokomachi K, Higaki T, Saito A, Miki K, Fujioka C, Ohno Y, Ohno Y, Kimura T, Murakami Y, Nagata Y
  • Organizer: 第74回日本放射線技術学会総会学術大会
• [Presentation] Relative biological effectiveness and relative dose-rate effect on Lipiodol based on the microdosimetric-kinetic model (2018)
  • Author(s): Kawahara D, Nakano H, Ozawa S, Saito A, Kimura T, Suzuki T, Tsuneda M, Tanaka S, Ohno Y, Murakami Y and Nagata Y
  • Organizer: ESTRO37
• [Presentation] Dual Energy CT を用いた造影剤物質特定及び線量計算システム構築に向けた最適な造影剤抽出方法の検討 (2017)
  • Author(s): 河原大輔
  • Organizer: 第73回日本放射線技術学会
  • Place of Presentation: パシフィコ横浜
  • Year and Date: 2017-04-12
• [Presentation] Dual Energy CT を用いた造影剤物質特定及び線量計算システム構築に向けた最適な造影剤抽出方法の検討 (2017)
  • Author(s): 河原大輔、小澤修一、斎藤明登、田中創大、他。
  • Organizer: 第73回日本放射線技術学会総会
• [Presentation] Iodine Extraction Method using Direct-Electron Density and CT value with Dual energy-CT (2017)
  • Author(s): D Kawahara, S Ozawa, T Nakashima, et al.
  • Organizer: AAPM 59th Annual Meeting & Exhibition
  • Int'l Joint Research
• [Presentation] Relative biological effectiveness study on Lipiodol based on the microdosimetric-kinetic model (2017)
  • Author(s): D Kawahara, S Ozawa, T Nakashima, et al.
  • Organizer: 8th Japan-Korea Joint Meeting on Medical Physics
  • Int'l Joint Research
• [Presentation] Contrast medium extraction system using direct-electron density- CT number method and dual CT number method with Dual energy-CT (2017)
  • Author(s): D Kawahara, S Ozawa, T Nakashima, et al.
  • Organizer: The 3rd International Conference on Radiological Science and Technology (ICRST)
  • Int'l Joint Research
• [Presentation] Dual Energy CT を用いた造影剤物質特定及び線量計算システムの開発に向けて (2016)
  • Author(s): 河原大輔
  • Organizer: 第16 回広島放射線治療研究会
  • Place of Presentation: アークホテル広島
• [Funded Workshop] AAPM 58th Annual Meeting & Exhibition (2016)
  • Place of Presentation: ワシントン(USA)
  • Year and Date: 2016-07-31