| Autor: |
Anthony T.C. Chan, Kenny S K Chan, Louis K Y Lee, Darrell T H Li |
| Rok vydání: |
2015 |
| Předmět: |
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| Zdroj: |
Medical Physics. 42:3504-3504 |
| ISSN: |
0094-2405 |
| DOI: |
10.1118/1.4925091 |
| Popis: |
Purpose: To examine the feasibility of using radiochromic film with advanced calibration techniques for absolute and relative dose measurement in patient-specific SBRT QA. Methods: Ten SBRT cases were randomly selected. The treatment plans were mapped to a cylindrical Perspex phantom for QA measurement. A radiochromic film of 8”x10” was cut into a large piece of 20×21cm2 and 2 small pieces of 4×4cm2 each. The large piece was inserted in the mid-plane of the phantom which was irradiated with the treatment beam. One of the small pieces was irradiated with known dose. All irradiated films were allowed to stabilize for 24 hours before scanning. The protocol of single-scan with recalibration was followed and the 2 small films were used to adjust the calibration curve. The treatment film was calibrated with the dose gradient regularization method by an in-house developed MATLab program. The calculated dose planes were then exported to RIT113V4.4. Both treatment films and planned dose planes were normalized to the corresponding prescribed fractional dose for analysis. Results: The analysis was performed by normalizing both the treatment film and the planned dose planes to the prescribed fractional dose. Isodose line comparison was performed to visually check the alignment of the isodose level of steep dose gradient regions. Good agreements were observed in all 10 cases. Gamma index analysis with tolerance of 3% and 2mm was also carried out for quantitative analysis. All 10 cases were reported with a gamma index passing percentage of at least 98.9%, which were higher than the institute’s passing criteria of over 95%. Conclusion: By employing recalibration and regularization-based calibration techniques, radiochromic film can measure both the absolute and relative dose of SBRT treatment plans. This study suggested that radiochromic film, with proper application of advanced calibration methods, can be a promising tool for patient-specific SBRT QA. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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