| Ali Wagdy,El Shahat, Khaled M.,Huda Ashry,Amaal El Shershaby,Hussein M. Metwally. A comparative study between flattening filter-free beams and flattening filter beams in radiotherapy treatment. Oncol Transl Med, 2017, 3: 260-266. |
| A comparative study between flattening filter-free beams and flattening filter beams in radiotherapy treatment |
| Received:August 08, 2016 Revised:January 20, 2018 |
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| KeyWord:flattening filter-free beam; flattening filter beam; breast cancer; treatment planning; beam characteristics; multileaf collimator |
| Author Name | Affiliation | Department | | Ali Wagdy | Al Galaa Oncology Center, Egypt | radiation oncology | | El Shahat, Khaled M. | Clinical Oncology Department-Faculty of Medicine-Al Azhar University, Cairo, Egypt | Clinical Oncology Department-Faculty | | Huda Ashry | National Center for Radiation Research and Technology-AEA, Egypt | National Center for Radiation Research and Technology-AEA, Egypt | | Amaal El Shershaby | Physics Department Women College for Arts Science and Education-Ain Sham University, Cairo,Egypt | Physics Department Women College for Arts Science and Education-Ain Sham University, Cairo,Egypt | | Hussein M. Metwally | Oncology Department, Faculty of Medicine, Fayoum University, Cairo, Egypt +Dar Al Fouad Hospital-Radiation Unit, Cairo, Egypt | Clinical Oncology Department-Faculty |
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| Abstract: |
| Objective The aim of current study was to evaluation the physical parameters of FFF (Flattening Filter Free) energies in comparison with the standard energies used (flattening filter) in addition for clinical application like breast cancer treatment and palliative case for 6MV FFF and 10MV FFF respectively. Methods The main characteristics of the photon beams have been analyzed using specific data generated by a Varian True Beam linear accelerator( linac), ( Varian Medical Systems, Inc., Palo Alto, CA) linac having both FFF and FF beams of 6 and 10 MV energy, respectively, Eclipse treatment system for comparison, dosimetric system for relative and absolute dosimetry. We Compared all physical parameter for FFF versus FF and some clinical application for both energies 6 and 10 were included in current study for two sites cancer patients as example for planning to evaluation some parameter in each plan with different energy for example coverage of target volume, skin dose and organs at risk sparing (OAR).
Results The magnitude of contaminating electrons of FFF beam is relatively small in compared with standard for both energies and as a consequence the depth of dose maximum shows weak dependence on field size variation. Lateral dose profiles of FFF beam differ significantly from the FF beam for both energies 6 and 10 MV (P < 0.05). The central peak in the lateral profiles of FFF beam is pronounced only for medium to large field sizes. The higher the energy the more pronounced is the central peak. The shape of the lateral beam profile of an FFF beam changes slightly with depth due to a significantly reduced off-axis softening effect and hence the depth--dose characteristic remains almost constant across the field even for large field sizes. In clinical application we shown a significant difference between dose distribution for 6MV (FFF) in target coverage and doses for organs at risk versus 6 MV (FF) due to difference in depth of maximum dose and applicability for good distribution with FFF beam in case for breast cancer patient and good coverage for palliative treatment for bone Metastasis Using 10 MV(FFF) in compared with standard energy 10MV (FF).
Conclusion There are significant difference between dose distribution for 6MV (FFF) and 10MV(FFF) in target coverage and doses for organs at risk versus flattening energy due to difference in depth of maximum dose and applicability for good distribution with FFF beam, sparing for OARs and reduction in the time of treatment due to highest dose rate for FFF more than standard energies. |
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