Image-guided radiation therapy using computed tomography in radiotherapy

Winky Wing Ki Fung, Wing Cheung Vincent Wu

Research output: Journal article publicationReview articleAcademic researchpeer-review

5 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)121-136
Number of pages16
JournalJournal of Radiotherapy in Practice
Issue number2
Publication statusPublished - 1 Jun 2011


  • computed tomography
  • Image-guided RT
  • inter-fractional uncertainties
  • treatment verification

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging


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