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Title: SU-F-T-522: Dosimetric Study of Junction Dose in Double Isocenter Flatten and Flatten Filter Free IMRT and VMAT Plan Delivery

Abstract

Purpose: To quantify the dosimetric accuracy of junction dose in double isocenter flattened and flatten filter free(FFF) intensity modulated radiation therapy(IMRT) and volumetric modulated arc therapy(VMAT) plan delivery using pelvis phantom. Methods: Five large field pelvis patients were selected for this study. Double isocenter IMRT and VMAT treatment plans were generated in Eclipse Treatment planning System (V.11.0) using 6MV FB and FFF beams. For all the plans same distance 17.0cm was kept between one isocenter to another isocenter. IMRT Plans were made with 7 coplanar fields and VMAT plans were made with full double arcs. Dose calculation was performed using AAA algorithms with dose grid size of 0.25 cm. Verification plans were calculated on Scanditronix Wellhofer pelvis slab phantom. Measurement point was selected and calculated, where two isocenter plan fields are overlapping, this measurement point was kept at distance 8.5cm from both isocenter. The plans were delivered using Varian TrueBeamTM machine on pelvis slab phantom. Point dose measurements was carried out using CC13 ion chamber volume of 0.13cm3. Results: The measured junction point dose are compared with TPS calculated dose. The mean difference observed was 4.5%, 6.0%, 4.0% and 7.0% for IMRT-FB,IMRT-FFF, VMAT-FB and VMAT-FFF respectively. The measured dose resultsmore » shows closer agreement with calculated dose in Flatten beam planning in both IMRT and VMAT, whereas in FFF beam plan dose difference are more compared with flatten beam plan. Conclusion: Dosimetry accuracy of Large Field junction dose difference was found less in Flatten beam compared with FFF beam plan delivery. Even though more dosimetric studies are required to analyse junction dose for FFF beam planning using multiple point dose measurements and fluence map verification in field junction area.« less

Authors:
; ; ; ; ;  [1]
  1. Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, Delhi (India)
Publication Date:
OSTI Identifier:
22649108
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BEAMS; IONIZATION CHAMBERS; PELVIS; PHANTOMS; PLANNING; RADIATION DOSES; RADIOTHERAPY

Citation Formats

Samuvel, K, Yadav, G, Bhushan, M, Tamilarasu, S, Kumar, L, and Suhail, M. SU-F-T-522: Dosimetric Study of Junction Dose in Double Isocenter Flatten and Flatten Filter Free IMRT and VMAT Plan Delivery. United States: N. p., 2016. Web. doi:10.1118/1.4956707.
Samuvel, K, Yadav, G, Bhushan, M, Tamilarasu, S, Kumar, L, & Suhail, M. SU-F-T-522: Dosimetric Study of Junction Dose in Double Isocenter Flatten and Flatten Filter Free IMRT and VMAT Plan Delivery. United States. doi:10.1118/1.4956707.
Samuvel, K, Yadav, G, Bhushan, M, Tamilarasu, S, Kumar, L, and Suhail, M. Wed . "SU-F-T-522: Dosimetric Study of Junction Dose in Double Isocenter Flatten and Flatten Filter Free IMRT and VMAT Plan Delivery". United States. doi:10.1118/1.4956707.
@article{osti_22649108,
title = {SU-F-T-522: Dosimetric Study of Junction Dose in Double Isocenter Flatten and Flatten Filter Free IMRT and VMAT Plan Delivery},
author = {Samuvel, K and Yadav, G and Bhushan, M and Tamilarasu, S and Kumar, L and Suhail, M},
abstractNote = {Purpose: To quantify the dosimetric accuracy of junction dose in double isocenter flattened and flatten filter free(FFF) intensity modulated radiation therapy(IMRT) and volumetric modulated arc therapy(VMAT) plan delivery using pelvis phantom. Methods: Five large field pelvis patients were selected for this study. Double isocenter IMRT and VMAT treatment plans were generated in Eclipse Treatment planning System (V.11.0) using 6MV FB and FFF beams. For all the plans same distance 17.0cm was kept between one isocenter to another isocenter. IMRT Plans were made with 7 coplanar fields and VMAT plans were made with full double arcs. Dose calculation was performed using AAA algorithms with dose grid size of 0.25 cm. Verification plans were calculated on Scanditronix Wellhofer pelvis slab phantom. Measurement point was selected and calculated, where two isocenter plan fields are overlapping, this measurement point was kept at distance 8.5cm from both isocenter. The plans were delivered using Varian TrueBeamTM machine on pelvis slab phantom. Point dose measurements was carried out using CC13 ion chamber volume of 0.13cm3. Results: The measured junction point dose are compared with TPS calculated dose. The mean difference observed was 4.5%, 6.0%, 4.0% and 7.0% for IMRT-FB,IMRT-FFF, VMAT-FB and VMAT-FFF respectively. The measured dose results shows closer agreement with calculated dose in Flatten beam planning in both IMRT and VMAT, whereas in FFF beam plan dose difference are more compared with flatten beam plan. Conclusion: Dosimetry accuracy of Large Field junction dose difference was found less in Flatten beam compared with FFF beam plan delivery. Even though more dosimetric studies are required to analyse junction dose for FFF beam planning using multiple point dose measurements and fluence map verification in field junction area.},
doi = {10.1118/1.4956707},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}