Depth dose dependence of the mouse bone using kilovoltage photon beams: A Monte Carlo study for small-animal irradiation |
| |
| Authors: | James CL Chow |
| |
| Institution: | 1. Department of Radiation Oncology, University of Toronto and Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, ON, Canada M5G 2M9;2. Department of Physics, Ryerson University, Toronto, ON, Canada M5B 2K3;1. Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia;2. Clinical Oncology Unit, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia;3. Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia;4. Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom;1. Department of Radiation Oncology, University of Toronto, Toronto, Canada;2. Department of Radiation Physics, Princess Margaret Cancer Center, Toronto, Canada;3. Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI 48109, USA;1. Universitätsklinikum Hamburg-Eppendorf, Ambulanzzentrum des UKE GmbH, Bereich Strahlentherapie, Martinistraße 52, 20246 Hamburg, Germany;2. Universitätsklinikum Hamburg-Eppendorf, Zentrum für Experimentelle Medizin, Institut für Anatomie und Experimentelle Morphologie, Martinistraße 52, 20246 Hamburg, Germany;1. Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, China;2. China CDC Key Laboratory of Radiological Protection and Nuclear Emergency, National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention, Beijing 100088, China;3. Affiliated Hospital of China Institute for Radiation Protection, Taiyuan, Shanxi Province 030006, China;1. Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina;2. Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, North Carolina;3. Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina |
| |
| Abstract: | This study investigated the dose enhancement due to the presence of mouse bone irradiated by the kilovoltage (kV) photon beams. Dosimetry of the bone associated with soft and lung tissue was determined by Monte Carlo simulations using the EGSnrc-based code in millimeter scale. Two inhomogeneous phantoms with 2 mm of bone layer sandwiched by: (1) water and lung (bone–lung phantom); and (2) water (bone–water phantom), were used. Relative depth doses along the central beam axes in the phantoms and dose enhancement ratios (bone dose in the above inhomogeneous phantoms to the dose at the same point in the water phantom) were determined using the 100 and 225 kVp photon beams. For the 100 kVp photon beams, the depth dose gradient in the bone was significantly larger compared to that in a water phantom without the bone. This is due to the beam hardening effect that some low-energy photons were filtered out in the deeper depth, resulting in less photoelectric interactions and hence energy depositions in the bone. Moreover, dose differences between the top and downstream (bottom) bone edges at depths of 1–5 mm were 168–192% and 149–166% for the bone–lung and bone–water phantom, respectively. These differences were larger than 21–27% (bone–lung) and 12–23% (bone–water) for the 225 kVp photon beams. The maximum dose enhancement ratio in the bone for the bone–lung and bone–water phantoms in various depths was about 5.7 using the 100 kVp photon beams. This ratio was larger than two times of that (2.4) for the 225 kVp photon beams. It is concluded that, apart from the basic beam characteristics such as attenuation and penumbra, which are related to the photon beam energy in the mouse irradiation, the bone dose is another important factor to consider when selecting the beam energy in the small-animal treatment planning, provided that the bone dose enhancement is a concern in the preclinical model. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
