Zeinali-Rafsanjani, Banafsheh, Mosleh-Shirazi, Mohammad Amin, Faghihi, Reza, Saeedi-Moghadam, Mahdi, Jalli, Reza. (1397). Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study. , 15(Special Issue-12th. Iranian Congress of Medical Physics), 333-333. doi: 10.22038/ijmp.2019.12987
Banafsheh Zeinali-Rafsanjani; Mohammad Amin Mosleh-Shirazi; Reza Faghihi; Mahdi Saeedi-Moghadam; Reza Jalli. "Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study". , 15, Special Issue-12th. Iranian Congress of Medical Physics, 1397, 333-333. doi: 10.22038/ijmp.2019.12987
Zeinali-Rafsanjani, Banafsheh, Mosleh-Shirazi, Mohammad Amin, Faghihi, Reza, Saeedi-Moghadam, Mahdi, Jalli, Reza. (1397). 'Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study', , 15(Special Issue-12th. Iranian Congress of Medical Physics), pp. 333-333. doi: 10.22038/ijmp.2019.12987
Zeinali-Rafsanjani, Banafsheh, Mosleh-Shirazi, Mohammad Amin, Faghihi, Reza, Saeedi-Moghadam, Mahdi, Jalli, Reza. Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study. , 1397; 15(Special Issue-12th. Iranian Congress of Medical Physics): 333-333. doi: 10.22038/ijmp.2019.12987

Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study

Iranian Journal of Medical Physics
مقاله 327، دوره 15، Special Issue-12th. Iranian Congress of Medical Physics، بهمن و اسفند 2018، صفحه 333-333
نوع مقاله: Conference Proceedings
شناسه دیجیتال (DOI): 10.22038/ijmp.2019.12987
نویسندگان
Banafsheh Zeinali-Rafsanjani1؛ Mohammad Amin Mosleh-Shirazi2؛ Reza Faghihi3؛ Mahdi Saeedi-Moghadam1؛ Reza Jalli1
1Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
2Ionizing and Non-Ionizing Radiation Protection Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Radiotherapy and Oncology Department, Shiraz University of Medical Sciences, Shiraz, Iran
3Department of Medical Radiation Engineering, School of Mechanical Engineering, Shiraz University, Shiraz, Iran Radiation Research Center, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
چکیده
Introduction: MRI-only treatment planning (TP) can be advantageous in paediatric radiotherapy. However, electron density extraction is necessary for dose calculation. Normally, after bone segmentation, a bulk density is assigned. However, the variation of bone bulk density in patients makes the creation of pseudo CTs challenging. This study aims to assess the effects of bone density variations in children on radiation attenuation and dose calculation for MRI-only TP.
 
Materials and Methods: Bone contents of<15-year-old children were calculated, and substituted in the Oak Ridge National Laboratory paediatric phantoms. The percentage depth dose and beam profile of 150 kVp and 6 MV photon and 6 MeV electron beams were then calculated using Xcom, MCNPX (Monte Carlo N-particle version X) and ORLN phantoms.
Results: Using 150 kVp X-rays, the difference in attenuation coefficient was almost 5% between an 11-year-old child and a newborn, and ~8% between an adult and a newborn. With megavoltage radiation, the differences were smaller but still important. For an 18 MV photon beam, the difference of radiation attenuation between an 11-year-old child and a newborn was 4% and~7.4% between an adult and a newborn. For 6 MeV electrons, dose differences were observed up to the 2 cm depth. The percentage depth dose difference between 1 and 10-year-olds was 18.5%, and between 10 and 15-year-olds was 24%.
Conclusion: The results suggest that for MRI-only TP of photon- or electron-beam radiotherapy, the bone densities of each age group should be defined separately for accurate dose calculation.
کلیدواژه‌ها
MR only treatment planning؛ Electron density؛ Pediatric radiotherapy؛ Monte Carlo؛ ORNL phantom
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