Organ doses from a proton gantry-mounted cone-beam computed tomography system characterized with MCNP6 and GATE
| Autor: | Oscar Ardenfors, Alexandru Dasu, Gavin Poludniowski, Thomas Henry, Irena Gudowska |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Adult Cone beam computed tomography medicine.diagnostic_test Proton Phantoms Imaging Monte Carlo method Biophysics General Physics and Astronomy Computed tomography General Medicine Cone-Beam Computed Tomography Radiation Dosage 030218 nuclear medicine & medical imaging Computational physics 03 medical and health sciences 0302 clinical medicine Monte carlo code 030220 oncology & carcinogenesis medicine Humans Radiology Nuclear Medicine and imaging Protons Monte Carlo Method AND gate |
| Zdroj: | Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB). 53 |
| ISSN: | 1724-191X |
| Popis: | To determine organ doses from a proton gantry-mounted cone-beam computed tomography (CBCT) system using two Monte Carlo codes and to study the influence on organ doses from different acquisition modes and repeated imaging.The CBCT system was characterized with MCNP6 and GATE using measurements of depth doses in water and spatial profiles in air. The beam models were validated against absolute dose measurements and used to simulate organ doses from CBCT imaging with head, thorax and pelvis protocols. Anterior and posterior 190° scans were simulated and the resulting organ doses per mAs were compared to those from 360° scans. The influence on organ doses from repeated imaging with different imaging schedules was also investigated.The agreement between MCNP6, GATE and measurements with regard to depth doses and beam profiles was within 4% for all protocols and the corresponding average agreement in absolute dose validation was 4%. Absorbed doses for in-field organs from 360° scans ranged between 6 and 8 mGy, 15-17 mGy and 24-54 mGy for the head, thorax and pelvis protocols, respectively. Cumulative organ doses from repeated CBCT imaging ranged between 0.04 and 0.32 Gy for weekly imaging and 0.2-1.6 Gy for daily imaging. The anterior scans resulted in an average increase in dose per mAs of 24% to the organs of interest relative to the 360° scan, while the posterior scan showed a 37% decrease.A proton gantry-mounted CBCT system was accurately characterized with MCNP6 and GATE. Organ doses varied greatly depending on acquisition mode, favoring posterior scans. |
| Databáze: | OpenAIRE |
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