UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2022-07-01 16:04

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Conference: Bucharest University Faculty of Physics 2019 Meeting


Section: Biophysics; Medical Physics


Title:
Verification of dosimetric accuracy of two Elekta Infinity matched linacs


Authors:
Lucia E. ENCIU (1,2), Mihai D. SUDITU (1), Dmitri V. SCORTESCU (1), Adriana ALEXE (1), Loredana BUTU (1), Gabriela MANOLESCU (1)


*
Affiliation:
1) Medeuropa Radiation Therapy Center, Constanta, Romania


2) University of Bucharest, Faculty of Physics, Magurele, Romania


E-mail
enciu_lucia@yahoo.com


Keywords:
Radiation therapy, LINAC, dosimetry


Abstract:
The purpose of this study was to check the differences related to delivered radiation dose by two Elekta Infinity matched medical linear accelerators. Both Elekta Infinity LINACs can deliver 6 MV and 10 MV photon beams and are equipped with 160 leaves Agility collimator. In modern radiation therapy departments, the use of matched medical linear accelerators has important benefits for avoiding patient treatment breaks and optimizing clinical workflow. Dosimetric accuracy is critical when switching patients among mechanical and beam-matched LINACs. Correspondence of the mechanical parameters, like gantry, collimator, couch rotation accuracy, field size were analyzed after machine installation. Beam data measurements such as PDD (percentage depth dose) and beam profiles curves, output factors, and multileaf collimator parameters were compared for both beam-matched linacs. For VMAT plans, the dose verification was made with Octavius 4D dosimetry system and the calculated and measured dose distributions were compared by gamma analysis method with Verisoft software for different clinical cases. The agreement between reference dose for both LINACs was checked, in accordance with AIEA TRS 398 Code of Practice for 6 MV and 10 MV photons energy, by using ionization chambers and radiophotoluminescent dosimeters. All the investigated parameters have shown a good agreement between LINACs, within 1 % expected tolerance.


References:

1-Vi Nhan Nguyen, Brian Wang, Chengyu Shi - A Sensitivity Dosimetry Study of the Setup Uncertainties during Machine Commissioning and Annual QA,International Journal of Medical Physics, Clinical Engineering and Radiation Oncology

Vol.05 No.04(2016)

2 -P. Fenoglietto, M. Khodri, D. Nguyen, F. Josserand-Pietri and N. Aillères -Twin machines validation for VMAT treatments using electronic portal-imaging device: a multicenter study,Radiation Oncology (2016)