Proton-radiography-based quality assurance of proton range compensator
| Autor: | Seungryong Cho, Jungwon Kwak, Seyjoon Park, Young Kyung Lim, Dong Ho Shin, Sungkoo Cho, Joo-Young Kim, Dong Yun Kang, Dae-Hyun Kim, Jeong-Hoon Park, Sung-Yong Park, Jiseoc Lee, Se Byeong Lee, Chiyoung Jeong, J. I. Shin, Byung Jun Min |
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| Rok vydání: | 2013 |
| Předmět: |
Quality Control
Film Dosimetry Materials science Proton Calibration curve Imaging phantom Standard deviation Optics Proton Therapy Calibration Humans Scattering Radiation Computer Simulation Radiology Nuclear Medicine and imaging Radiological and Ultrasound Technology Phantoms Imaging business.industry Radiotherapy Planning Computer-Assisted Reproducibility of Results Radiotherapy Dosage Radiography Mockup Industrial radiography business Quality assurance Algorithms |
| Zdroj: | Physics in Medicine and Biology. 58:6511-6523 |
| ISSN: | 1361-6560 0031-9155 |
| Popis: | The aim of this work was to study the feasibility of proton radiography (pRad) as a patient-specific range compensator (RC) quality assurance (QA) tool and to validate its clinical utility by performing QA on RCs having three kinds of possible defects. In order to achieve pRad for a single EBT film, proton beam currents were modulated with new weighting factors, maximizing the linearity of optical-density-to-thickness ratio. Two RCs, examined to be accurately manufactured as planned, were selected to estimate the feasibility of our pRad. The optical densities of the EBT film on which the RC was irradiated with the modulated proton beam were digitized to pixel values (pv) and then converted to thickness using a thickness-pv calibration curve. The thickness information on the pRad was compared with plan data that had been extracted from treatment planning system. The mean thickness difference (TD) over the flat RC regions was calculated as 0.39 mm, and the standard deviation as 0.22 mm, and the proton scattering effect was analyzed by step phantom measurement. Even proton scattering effected a TD of over 1 mm in the large gradient region, the percentage of pixels over the acceptance criterion was only within 1.11% and 3.49%, respectively, when a 1 mm distance to agreement tolerance limit was applied. The QA results for both precisely and imprecisely manufactured RCs demonstrated the high potential utility and clinical applicability of the pRad-based RC QA tool. |
| Databáze: | OpenAIRE |
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