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Evaluation Study of IMRT Plans in Octavius and Slaps Phantoms |
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PP: 115-121 |
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doi:10.18576/jrna/100204
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Author(s) |
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Shimaa. A. Fouad,
Khaled. M. El-Shahat,
Atef El-Taher,
Wafaa Rashed,
M. A. Ghoneim,
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Abstract |
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| Intensity-modulated radiation therapy (IMRT) is considered one of the important techniques for the treatment of cancer patients so, the object of this work is to evaluate (IMRT) plans. This process required a specific dosimetry system but in this work, we used an Octavius phantom 2D array of detectors 1500(T10044). Firstly, calibrated this system by measuring square field sizes 5, 10, 15, and 20 for three-photon energies 6MV, 10MV, and 15MV in coronal, sagittal, and axial phases for plan views. we used an Elekta (An Agility synergy platform) linear accelerator in the South Egypt Cancer Institute (Assiut University, Egypt) with steep and shoot technique in IMRT. We verified 20 patients with IMRT plans using the MONACO computer treatment planning system (TPS) which can be calculated by using the Monte Carlo algorithm which is used only in (IMRT). We fulfill Two verification plans for each patient, one applied on 4D PTW Octavius phantom with true gantry angles of IMRT plan and the other plan applied on solid waterproof slaps phantom with zero (0°) gantry angle in all beams of the plan. The comparing data between measured and calculated doses for the two concerned plans will analyzed by the PTW MEPHESTO VERISOFT PATIENT PLAN VERIFICATION software program. Two measuring processes will be run the first one applied with local dose (all doses of calculated volume) and global dose (maximum dose of calculated volume) each of them was calculated in 2D, 3D, and 4D. Only 4D will be performed calculation in Octavious Phantom with true angles planes. indicate that the Gamma (γ) average (the gamma passing rate (GPR)) identity during applying different types of gamma analyses in 2D and 3D for true angles Octavious planes firstly for a global maximum of calculating volume respectively are 98, 99, and 4D 98.3. in local dose 2D, 3D, and 4D respectively are 89, 94.6, 91.6. secondly, The results for 2D, and 3D in slaps phantom planes with zero gantry angle in global max and local dose are respectively 99.7, 99.8, 88.6, 74.5. The Gamma passing rate (GPR) in the verification of IMRT planes is dependent on the angles of plans, so the detectors in the 2D array depend on the gantry angle these are whether in global max dose or local dose otherwise, the Gamma passing rate (GPR) in global max are greater than in local dose. In conclusion, our study shows that the effectiveness of IMRT plans is dependent on the angles of the plan, and the detectors used in the 2D array are dependent on the gantry angle. |
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