• Title/Summary/Keyword: imaging physics

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The Principle of the NMR Image (NMR CT의 원리)

  • 조장희;김홍석
    • Journal of Biomedical Engineering Research
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    • v.3 no.2
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    • pp.119-122
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    • 1982

  • This paper presents the principles of image formation in NMR(Nuclear Magnetic Resonance) tomography. NMR tomographic imaging is a newly emerging, noninvasive, three-dimensional imaging technique. This new technique is an interdisciplinary science which encompasses the latest technologies in electrical, electronics, computers, physics, chemistry, mathematics, and medical sciences.

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Feasibility of Proton Chemical Shift Imaging with a Stereotactic Headframe

  • 백현만;최보영;손병철;정성택;이형구;서태석
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2003.09a
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    • pp.72-72
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    • 2003

  • Purpose: To prove feasibility of proton chemical shift imaging (lH CSI) during stereotactic procedure, authors performed IH CSI in combination with a stereotactic headframe and selected targets according to local metabolic information, evaluated the pathologic results. Methods: The 1H CSI directed stereotactic biopsy was performed in five patients. 1H CSI was performed before conventional stereotactic MRI with gadolinium enhancement for stereotactic coordinates. The metabolite images expressed as integral ratios, Cho/Cr and Lac/Cr, were displayed in different colors. The stereotactic target coordinates were correlated with the coordinates from the 1H CSI images. Results: The final pathologic results obtained were concordant with the local metabolic information from 1H CSI. We believe that 1H CSI-directed stereotatic biopsy has the potential to significantly improve the accuracy of stereotactic biopsy targeting. Conclusions : Metabolic signals derived from 1H CSI could give us more direct clues for stereotactic target selection during the subsequent conventional stereotactic MR imaging. 1H CSI was feasible with the stereotatic headframe in place. The final pathologic results obtained were concordant with the local metabolic information from 1H CSI. Acknowledgement: This study was supported by a grant of the Center for Functional and Metabolic Imaging Technology, Ministry of Health & Welfare, Republic of Korea (02-PJ3-PG6-EV07-0002).

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Automatic Multileaf Collimation Quality Assurance for IMRT using Electronic Portal Imaging

  • Jin, Ho-Sang;Jason W. Sohn;Suh, Tae-Suk
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.305-308
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    • 2002

  • More complex radiotherapy techniques using multi leaf collimation(MLC) such as intensity-modulated radiation therapy(IMRT) has been increasing the significance of verification of leaf position and motion. Due to the reliability and robustness, quality assurance(QA) of MLC is usually performed with portal films. However, the advantage of ease of use and capability of providing digital data of electronic portal imaging devices(EPIDs) have attracted many attentions as alternatives of films for routine quality assurance in spite of the concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In our work, the method of routine QA of MLC using electronic portal imaging(EPI) was developed. The verification of availability of EPI images for routine QA was performed by comparison with those of the portal films which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed test patterns of dynamic MLC were applied to image acquisition. Quantitative off-line analysis using edge detection algorithm enhanced the verification procedure in addition to on-line qualitative visual assessment. In conclusion, the EPI is available enough for routine QA with the accuracy of portal films.

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