Prog Med Phys.  2022 Dec;33(4):37-52. 10.14316/pmp.2022.33.4.37.

Image Guided Radiation Therapy

• Hwang UJ
• Min BJ
• Kim M
• Kim KH

• KMID: 2537871
• DOI: http://doi.org/10.14316/pmp.2022.33.4.37

Abstract

Over the past decades, radiation therapy combined with imaging modalities that ensure optimal image guidance has revolutionized cancer treatment. The two major purposes of using imaging modalities in radiotherapy are to clearly delineate the target prior to treatment and set up the patient during radiation delivery. Image guidance secures target position prior to and during the treatment. High quality images provide an accurate definition of the treatment target and the possibility to reduce the treatment margin of the target volume, further lowering radiation toxicity and improving the quality of life of cancer patients. In this review, the various types of image guidance modalities used in radiation therapy are distinguished into ionized (kilovoltage and megavoltage image) and nonionized imaging (magnetic resonance image, ultrasound, surface imaging, and radiofrequency). The functional aspects, advantages, and limitation of imaging using these modalities are described as a subsection of each category. This review only focuses on the technological viewpoint of these modalities and any clinical aspects are omitted. Image guidance is essential, and its importance is rapidly increasing in modern radiotherapy. The most important aspect of using image guidance in clinical settings is to monitor the performance of image quality, which must be checked during the periodic quality assurance process.

Keyword

Radiation therapy; Image guided radiation therapy; Ionizing image; Nonionizing image

Figure

• 

  Fig. 1 IGRT techniques categorized based on their characteristics. MR-Linac, US, and surface imaging are categorized as 2D and tracking imaging methods because their tracking ability is limited in 2D coordinates to date. 2D, two-dimensional; CBCT, cone beam computed tomography; CT, computed tomography; EPID, electronic portal imaging device; IGRT, image guided radiation therapy; MR-Linac, magnetic resornance linear accelerator; OBI, onboard imager; PET/CT, positron emission tomography/computed tomography; RF, radio frequency; US, ultrasound.

Reference

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