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BioMed Research International
Volume 2014, Article ID 231090, 9 pages
Review Article

The Role of Imaging in Radiation Therapy Planning: Past, Present, and Future

1Department of Radiation Oncology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA
2Philips Healthcare, MR Therapy, Cleveland, OH, USA
3Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA
4Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA

Received 19 December 2013; Accepted 17 February 2014; Published 10 April 2014

Academic Editor: Tzu-Chen Yen

Copyright © 2014 Gisele C. Pereira et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning. Despite some disadvantages, CT remains the only three-dimensional imaging modality used for dose calculation. Newer image modalities, such as magnetic resonance (MR) imaging and positron emission tomography (PET), are also used secondarily in the treatment-planning process. MR, with its better tissue contrast and resolution than those of CT, improves tumor definition compared with CT planning alone. PET also provides metabolic information to supplement the CT and MR anatomical information. With emerging molecular imaging techniques, the ability to visualize and characterize tumors with regard to their metabolic profile, active pathways, and genetic markers, both across different tumors and within individual, heterogeneous tumors, will inform clinicians regarding the treatment options most likely to benefit a patient and to detect at the earliest time possible if and where a chosen therapy is working. In the post-human-genome era, multimodality scanners such as PET/CT and PET/MR will provide optimal tumor targeting information.