A correction-based dose calculation algorithm for kilovoltage x rays
- Vanderbilt-Ingram Cancer Center, Department of Radiation Oncology, Vanderbilt University School of Medicine and Department of Physics and Astronomy, Vanderbilt University College of Art and Sciences B-902, TVC, 1301 Medical Center Drive, Nashville, Tennessee 37232-5671 (United States)
Frequent and repeated imaging procedures such as those performed in image-guided radiotherapy (IGRT) programs may add significant dose to radiosensitive organs of radiotherapy patients. It has been shown that kV-CBCT results in doses to bone that are up to a factor of 3-4 higher than those in surrounding soft tissue. Imaging guidance procedures are necessary due to their potential benefits, but the additional incremental dose per treatment fraction may exceed an individual organ tolerance. Hence it is important to manage and account for this additional dose from imaging for radiotherapy patients. Currently available model-based dose calculation methods in radiation treatment planning (RTP) systems are not suitable for low-energy x rays, and new and fast calculation algorithms are needed for a RTP system for kilovoltage dose computations. This study presents a new dose calculation algorithm, referred to as the medium-dependent-correction (MDC) algorithm, for accurate patient dose calculation resulting from kilovoltage x rays. The accuracy of the new algorithm is validated against Monte Carlo calculations. The new algorithm overcomes the deficiency of existing density correction based algorithms in dose calculations for inhomogeneous media, especially for CT-based human volumetric images used in radiotherapy treatment planning.
- OSTI ID:
- 22095272
- Journal Information:
- Medical Physics, Vol. 35, Issue 12; Other Information: (c) 2008 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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