Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam
Introduction: The design characteristics of ionization chambers are critical for the accurate measurement of Percentage Surface Dose (PSD) and Percentage Depth Dose (PDD) in the build-up region. This study assesses the over-response correction in PSD and PDD for different field sizes, using Markus a...
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Mashhad University of Medical Sciences
2024-07-01
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| Series: | Iranian Journal of Medical Physics |
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| Online Access: | https://ijmp.mums.ac.ir/article_22854_146b5af4eb242f46f7bc0b3ee66ca986.pdf |
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| author | Deepali Patil Mukesh Zope DINESH SAROJ Aslam P. A. Basil George |
| author_facet | Deepali Patil Mukesh Zope DINESH SAROJ Aslam P. A. Basil George |
| author_sort | Deepali Patil |
| collection | DOAJ |
| description | Introduction: The design characteristics of ionization chambers are critical for the accurate measurement of Percentage Surface Dose (PSD) and Percentage Depth Dose (PDD) in the build-up region. This study assesses the over-response correction in PSD and PDD for different field sizes, using Markus and ROOS fixed separation parallel-plate ionization chambers.
Material and Methods: The Sun Nuclear Corporation SNC 350P ROOS and PTW Markus parallel plate ionization chambers were used to measure 6 MV photon beam PDD along the central axis in the build-up region.The experiment was performed on a Solid Water® HE phantom with a density of 1.032 g/cm3.The Measurements were taken at a Source Surface distance (SSD) of 100 cm with Field sizes of 10x10cm2,20x20 cm2, and 30x30cm2 and at variable depths.
Results: For field sizes of 10x10 cm2, 20x20 cm2, and 30x30 cm2 at a source-to-axis distance (SAD) of 100 cm, the PSD values obtained with the Markus chamber, before and after applying Rawlinson's equation for over-response correction, were as follows: 35.11%, 42.92%, 50.72% (before correction) and 28.37%, 36.19%, 44.05% (after correction). Similarly, the PSD values measured using the ROOS chamber, before and after applying over-response correction, were as follows: 41.61%, 50.50%, 58.04% (before correction), and 33.96%, 42.87%, 50.38% (after correction).
Conclusion: The application of over-response correction using Rawlinson's equation improved the accuracy of measurements for both chambers, emphasizing the significance of employing appropriate correction techniques to ensure precise dose measurements in the build-up region using ionization chambers. |
| format | Article |
| id | doaj-art-a972d60c311149918070ef94102a287b |
| institution | Kabale University |
| issn | 2345-3672 |
| language | English |
| publishDate | 2024-07-01 |
| publisher | Mashhad University of Medical Sciences |
| record_format | Article |
| series | Iranian Journal of Medical Physics |
| spelling | doaj-art-a972d60c311149918070ef94102a287b2025-01-18T07:32:33ZengMashhad University of Medical SciencesIranian Journal of Medical Physics2345-36722024-07-0121427227910.22038/ijmp.2023.71464.226422854Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon BeamDeepali Patil0Mukesh Zope1DINESH SAROJ2Aslam P. A.3Basil George4Department of Medical Physics,State Cancer Institute, Indira Gandhi Institute of Medical Sciences,Patna, Bihar.Indira Gandhi Institute Of Medical Sciences ,Sheikhpura ,PatnaBALCO Medical Center, Vedanta Research Foundation, New Raipur, atal Nagar, Chhattisgarh 493661Department of Radiation Oncology, Kiran Multi Super Speciality Hospital, Surat-395004, Gujarat.Department of Radiation Oncology, STARLIT Cancer Center, Ahmadabad-382350, Gujarat.Introduction: The design characteristics of ionization chambers are critical for the accurate measurement of Percentage Surface Dose (PSD) and Percentage Depth Dose (PDD) in the build-up region. This study assesses the over-response correction in PSD and PDD for different field sizes, using Markus and ROOS fixed separation parallel-plate ionization chambers. Material and Methods: The Sun Nuclear Corporation SNC 350P ROOS and PTW Markus parallel plate ionization chambers were used to measure 6 MV photon beam PDD along the central axis in the build-up region.The experiment was performed on a Solid Water® HE phantom with a density of 1.032 g/cm3.The Measurements were taken at a Source Surface distance (SSD) of 100 cm with Field sizes of 10x10cm2,20x20 cm2, and 30x30cm2 and at variable depths. Results: For field sizes of 10x10 cm2, 20x20 cm2, and 30x30 cm2 at a source-to-axis distance (SAD) of 100 cm, the PSD values obtained with the Markus chamber, before and after applying Rawlinson's equation for over-response correction, were as follows: 35.11%, 42.92%, 50.72% (before correction) and 28.37%, 36.19%, 44.05% (after correction). Similarly, the PSD values measured using the ROOS chamber, before and after applying over-response correction, were as follows: 41.61%, 50.50%, 58.04% (before correction), and 33.96%, 42.87%, 50.38% (after correction). Conclusion: The application of over-response correction using Rawlinson's equation improved the accuracy of measurements for both chambers, emphasizing the significance of employing appropriate correction techniques to ensure precise dose measurements in the build-up region using ionization chambers.https://ijmp.mums.ac.ir/article_22854_146b5af4eb242f46f7bc0b3ee66ca986.pdfradiation dosage percentage surface dose buildup dose dosimeters radiotherapy |
| spellingShingle | Deepali Patil Mukesh Zope DINESH SAROJ Aslam P. A. Basil George Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam Iranian Journal of Medical Physics radiation dosage percentage surface dose build up dose dosimeters radiotherapy |
| title | Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam |
| title_full | Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam |
| title_fullStr | Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam |
| title_full_unstemmed | Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam |
| title_short | Over-Response Correction of SNC 350p ROOS and PTW Markus Chambers in the Surface Dose and Build-Up Region Dosimetry of 6MV Photon Beam |
| title_sort | over response correction of snc 350p roos and ptw markus chambers in the surface dose and build up region dosimetry of 6mv photon beam |
| topic | radiation dosage percentage surface dose build up dose dosimeters radiotherapy |
| url | https://ijmp.mums.ac.ir/article_22854_146b5af4eb242f46f7bc0b3ee66ca986.pdf |
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