A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators
Introduction: To study the effect of the International Atomic Energy Agency (IAEA) TRS-483 recommended beam quality correction factor in reference dosimetry and to examine the recommended field output correction factor for relative dosimetry of 6-MV flattening filter free (FFF) small fields, used in...
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| Format: | Article |
| Language: | English |
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Mashhad University of Medical Sciences
2021-05-01
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| Series: | Iranian Journal of Medical Physics |
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| Online Access: | https://ijmp.mums.ac.ir/article_16003_fca9f029e208ec3da2954df57f0ccb6e.pdf |
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| author | Gopinath Mamballikalam Senthil kumar Clinto C.O Jaon bos R.C. Ahamed Basith P.M. |
| author_facet | Gopinath Mamballikalam Senthil kumar Clinto C.O Jaon bos R.C. Ahamed Basith P.M. |
| author_sort | Gopinath Mamballikalam |
| collection | DOAJ |
| description | Introduction: To study the effect of the International Atomic Energy Agency (IAEA) TRS-483 recommended beam quality correction factor in reference dosimetry and to examine the recommended field output correction factor for relative dosimetry of 6-MV flattening filter free (FFF) small fields, used in a Varian TrueBeam linear accelerator (LINAC). Material and Methods: The beam quality and field output correction for 6-MV FFF beams were adopted from the TRS-483 protocol. Monte Carlo (MC) simulation of the output factor was performed using the PENELOPE-based PRIMO software and compared with the TRS-483 corrected output factors. Two analytical anisotropic algorithm (AAA) models in the EclipseTM treatment planning system (TPS) were created; one with an output factor taken as the ratio of meter readings and one with an output factor obtained by multiplying the TRS-483 correction factor by the ratio of meter readings. Besides, box field and dynamic conformal arc (DCA) plans were created for both AAA models for verification and validation. The patient-specific quality assurances (QA) for ten different targets were performed, and deviations between the measured and TPS-calculated point doses in both models were examined. Results: Separate beam quality correction factors for FFF beams in the TRS-483 protocol only resulted in an improvement of 0.1% in reference dosimetry. The TRS-483 corrected output factor was in a better agreement with the MC-calculated output factor. For a patient-specific QA of DCA plans, the output factor-corrected AAA dose calculation algorithm showed a better agreement between the measured and simulated doses. Also, there was a smaller deviation (1.2%) for the smallest target of 0.23 cc (8 mm equivalent sphere diameter) used in this study. Conclusion:The field output factors for the LINAC small beams can be improved by incorporating the TRS-483 correction factors. However, the extent of improvement that can be expected depends on the source model of the calculation algorithm and how these well-generalized corrections are suitable for user beams and detectors. |
| first_indexed | 2024-12-18T00:22:39Z |
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| id | doaj.art-01cd303cc9494813ae2216e75c4f1367 |
| institution | Directory Open Access Journal |
| issn | 2345-3672 2345-3672 |
| language | English |
| last_indexed | 2024-12-18T00:22:39Z |
| publishDate | 2021-05-01 |
| publisher | Mashhad University of Medical Sciences |
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| series | Iranian Journal of Medical Physics |
| spelling | doaj.art-01cd303cc9494813ae2216e75c4f13672022-12-21T21:27:18ZengMashhad University of Medical SciencesIranian Journal of Medical Physics2345-36722345-36722021-05-0118317818610.22038/ijmp.2020.46236.172216003A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear AcceleratorsGopinath Mamballikalam0Senthil kumar1Clinto C.O2Jaon bos R.C.3Ahamed Basith P.M.41. R&D, Bharathiar University, Coimbatore, Tamilnadu, India 3. Aster Medcity, Kochi, Kerala, IndiaRajaji Hospital & Madurai Medical College, Madurai, Tamilnadu, IndiaAster Medcity, Kochi, Kerala, IndiaAster Medcity, Kochi, Kerala, IndiaAster Medcity, Kochi, Kerala, IndiaIntroduction: To study the effect of the International Atomic Energy Agency (IAEA) TRS-483 recommended beam quality correction factor in reference dosimetry and to examine the recommended field output correction factor for relative dosimetry of 6-MV flattening filter free (FFF) small fields, used in a Varian TrueBeam linear accelerator (LINAC). Material and Methods: The beam quality and field output correction for 6-MV FFF beams were adopted from the TRS-483 protocol. Monte Carlo (MC) simulation of the output factor was performed using the PENELOPE-based PRIMO software and compared with the TRS-483 corrected output factors. Two analytical anisotropic algorithm (AAA) models in the EclipseTM treatment planning system (TPS) were created; one with an output factor taken as the ratio of meter readings and one with an output factor obtained by multiplying the TRS-483 correction factor by the ratio of meter readings. Besides, box field and dynamic conformal arc (DCA) plans were created for both AAA models for verification and validation. The patient-specific quality assurances (QA) for ten different targets were performed, and deviations between the measured and TPS-calculated point doses in both models were examined. Results: Separate beam quality correction factors for FFF beams in the TRS-483 protocol only resulted in an improvement of 0.1% in reference dosimetry. The TRS-483 corrected output factor was in a better agreement with the MC-calculated output factor. For a patient-specific QA of DCA plans, the output factor-corrected AAA dose calculation algorithm showed a better agreement between the measured and simulated doses. Also, there was a smaller deviation (1.2%) for the smallest target of 0.23 cc (8 mm equivalent sphere diameter) used in this study. Conclusion:The field output factors for the LINAC small beams can be improved by incorporating the TRS-483 correction factors. However, the extent of improvement that can be expected depends on the source model of the calculation algorithm and how these well-generalized corrections are suitable for user beams and detectors.https://ijmp.mums.ac.ir/article_16003_fca9f029e208ec3da2954df57f0ccb6e.pdffff beams trs483 linear accelerator small field dosimetry |
| spellingShingle | Gopinath Mamballikalam Senthil kumar Clinto C.O Jaon bos R.C. Ahamed Basith P.M. A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators Iranian Journal of Medical Physics fff beams trs 483 linear accelerator small field dosimetry |
| title | A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators |
| title_full | A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators |
| title_fullStr | A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators |
| title_full_unstemmed | A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators |
| title_short | A Study of the Impact of TRS-483 Recommended Correction Factors for Dosimetry of Small Fields in Flattening Filter Free Beams used in TrueBeam Linear Accelerators |
| title_sort | study of the impact of trs 483 recommended correction factors for dosimetry of small fields in flattening filter free beams used in truebeam linear accelerators |
| topic | fff beams trs 483 linear accelerator small field dosimetry |
| url | https://ijmp.mums.ac.ir/article_16003_fca9f029e208ec3da2954df57f0ccb6e.pdf |
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