الفهرس 
TITLEOnly 14 pages are availabe for public view
 |  | from | 109 |  |  |
| | | from | 109 | | |
Abstract
In light of the current progress in radiotherapy methods and since high radiation doses are given to cancer patients, it has become necessary to establish the necessary powers and quality guarantees for radiotherapy devices and calibration devices in order to ensure the radiation dose calculations, the quality and accuracy of the calculation and movement of MLCs
The use of advanced radiotherapy techniques IMRT and VMAT, the transferred treatment plan, as well as the delivery of treatment in order to ensure the correct access to the patient by the machine for the prescribed dose, because it is a great opportunity for all cancer patients to benefit from these devices equipped with all modern technologies for radiotherapy.
Therefore, the purpose of this study was to do dosimetry, analyze and evaluate the properties of two specific regimens (120 HD-MLC and 120 MLC-MS) for IMRT and VMAT by using an imaging device and Titration and calculation of EPID doses.
In this study we have two parts; The first part is to perform the necessary calibration and quality assurance of the EPID for it to be used as a dosimetric instrument, then it was used to perform various quality assurance tests such as accuracy in positioning MLCs and velocity, stability of dynamic MLC output, transition between and within leaflets, separation dosimetry and verification of Multiple transport field. Standard field patterns such as crests, wedge, chair, garden fence test, picket fence test and sweepping gap for output were also evaluated. The second part was about making a comparison of MLC and dose accuracy of HD MLC and conventional MLC in IMRT and VMAT using treatment planning tools and portal dosimetry.
The patient dose quality assurance procedure consisted of absolute dose measurement of all fields at a depth of 5 cm on a hard water phantom using a PTW 30013 Waterproof Farmer® chamber and verification of the relative dose using EPID for all treatment areas along the transverse and coronal direction using IMRT and VMAT phantom.
Relative dose validation was performed using Varian’s validation software. The results of the conducted tests showed the good acceptance of the operation of the HD MLC-120 and conventional MLC-120 MS technology in the IMRT and VMAT process technology of the two Varian machines (UNIQUETM and VitalBeam®). The results of EPID were in complete agreement with the practical method.
So although there is no time to experiment in the morning device, this study shows that analyzing picket fence tests obtained from the Electronic Gateway Image Device (EPID) to detect MLC positioning errors is a fast and accurate method, such as MLC multi-parallel quality assurance. QA, which can be used in a quality assurance procedure to reduce the time a patient spends on quality assurance during IMRT/VMAT delivery.
MLC alignment errors can be quickly and accurately detected by analyzing wooden fence checks collected by EPID using a suitable home or business software application containing MLC QA. This strategy is immediately applicable to the morning regime. It allows to reduce the time spent by the affected person through the application of quality assurance methods. Quality Assurance of IMRT/VMAT Delivery When Patient Recruitment is Delayed - Target Quality Assurance.
Also, quality control of MLC leaf position was performed using EPID. In conclusion, EPID was found to be a suitable device for daily quality control of HD-MLC and MS-MLC of the linear accelerator. Linear accelerator quality control by EPID is generally faster with lower screen unit consumption and less chance of linear accelerator consumption. The results of this study therefore support the adoption of HD-MLC and MS-MLC in IMRT and VMAT treatment techniques using EPID as a dosimetric tool.