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Image-guided radiation therapy using computed tomography in radiotherapy

Published online by Cambridge University Press:  12 November 2010

Winky Wing Ki Fung  and
Vincent Wing Cheung Wu
Winky Wing Ki Fung*
Affiliation:
Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Hong Kong
Vincent Wing Cheung Wu
Affiliation:
Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
*
Correspondence to: Winky Wing Ki Fung, Department of Radiotherapy, G/F, Li Shu Pui Block, 2 Village Road, Happy Valley, Hong Kong. E-mail: [email protected]
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Abstract

The sharp dose gradients in intensity-modulated radiation therapy increase the treatment sensitivity to various inter- and intra-fractional uncertainties, in which a slight anatomical change may greatly alter the actual dose delivered. Image-guided radiotherapy refers to the use of advanced imaging techniques to precisely track and correct these patient-specific variations in routine treatment. It can also monitor organ changes during a radiotherapy course. Currently, image-guided radiotherapy using computed tomography has gained much popularity in radiotherapy verification as it provides volumetric images with soft-tissue contrast for on-line tracking of tumour. This article reviews four types of computed tomography-based image guidance systems and their working principles. The system characteristics and clinical applications of the helical, megavoltage, computed tomography, and kilovoltage, cone-beam, computed tomography systems are discussed, given that they are currently the most commonly used systems for radiotherapy verification. This article also focuses on the recent techniques of soft-tissue contrast enhancement, digital tomosynthesis, four-dimensional fluoroscopic image guidance, and kilovoltage/megavoltage, in-line cone-beam imaging. These evolving systems are expected to take over the conventional two-dimensional verification system in the near future and provide the basis for implementing adaptive radiotherapy.

Keywords

Image-guided RTtreatment verificationinter-fractional uncertaintiescomputed tomography
Type
Literature Review
Information
Journal of Radiotherapy in Practice , Volume 10 , Issue 2 , June 2011 , pp. 121 - 136
Copyright
Copyright © Cambridge University Press 2010

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